Merging debian version 1.65.0+dfsg1-2.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

12 files changed, 1675 insertions, 1055 deletions

diff --git a/compiler/rustc_metadata/src/creader.rs b/compiler/rustc_metadata/src/creader.rs
index 708d0b1fd..cfcceecbe 100644
--- a/compiler/rustc_metadata/src/creader.rs
+++ b/compiler/rustc_metadata/src/creader.rs
@@ -1,5 +1,9 @@
 //! Validates all used crates and extern libraries and loads their metadata
 
+use crate::errors::{
+    ConflictingGlobalAlloc, CrateNotPanicRuntime, GlobalAllocRequired, NoMultipleGlobalAlloc,
+    NoPanicStrategy, NoTransitiveNeedsDep, NotProfilerRuntime, ProfilerBuiltinsNeedsCore,
+};
 use crate::locator::{CrateError, CrateLocator, CratePaths};
 use crate::rmeta::{CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob};
 
@@ -29,7 +33,6 @@ use proc_macro::bridge::client::ProcMacro;
 use std::ops::Fn;
 use std::path::Path;
 use std::{cmp, env};
-use tracing::{debug, info};
 
 #[derive(Clone)]
 pub struct CStore {
@@ -263,7 +266,7 @@ impl<'a> CrateLoader<'a> {
     fn existing_match(&self, name: Symbol, hash: Option<Svh>, kind: PathKind) -> Option<CrateNum> {
         for (cnum, data) in self.cstore.iter_crate_data() {
             if data.name() != name {
-                tracing::trace!("{} did not match {}", data.name(), name);
+                trace!("{} did not match {}", data.name(), name);
                 continue;
             }
 
@@ -746,15 +749,10 @@ impl<'a> CrateLoader<'a> {
         // Sanity check the loaded crate to ensure it is indeed a panic runtime
         // and the panic strategy is indeed what we thought it was.
         if !data.is_panic_runtime() {
-            self.sess.err(&format!("the crate `{}` is not a panic runtime", name));
+            self.sess.emit_err(CrateNotPanicRuntime { crate_name: name });
         }
         if data.required_panic_strategy() != Some(desired_strategy) {
-            self.sess.err(&format!(
-                "the crate `{}` does not have the panic \
-                                    strategy `{}`",
-                name,
-                desired_strategy.desc()
-            ));
+            self.sess.emit_err(NoPanicStrategy { crate_name: name, strategy: desired_strategy });
         }
 
         self.cstore.injected_panic_runtime = Some(cnum);
@@ -774,10 +772,7 @@ impl<'a> CrateLoader<'a> {
 
         let name = Symbol::intern(&self.sess.opts.unstable_opts.profiler_runtime);
         if name == sym::profiler_builtins && self.sess.contains_name(&krate.attrs, sym::no_core) {
-            self.sess.err(
-                "`profiler_builtins` crate (required by compiler options) \
-                        is not compatible with crate attribute `#![no_core]`",
-            );
+            self.sess.emit_err(ProfilerBuiltinsNeedsCore);
         }
 
         let Some(cnum) = self.resolve_crate(name, DUMMY_SP, CrateDepKind::Implicit) else { return; };
@@ -785,18 +780,14 @@ impl<'a> CrateLoader<'a> {
 
         // Sanity check the loaded crate to ensure it is indeed a profiler runtime
         if !data.is_profiler_runtime() {
-            self.sess.err(&format!("the crate `{}` is not a profiler runtime", name));
+            self.sess.emit_err(NotProfilerRuntime { crate_name: name });
         }
     }
 
     fn inject_allocator_crate(&mut self, krate: &ast::Crate) {
         self.cstore.has_global_allocator = match &*global_allocator_spans(&self.sess, krate) {
             [span1, span2, ..] => {
-                self.sess
-                    .struct_span_err(*span2, "cannot define multiple global allocators")
-                    .span_label(*span2, "cannot define a new global allocator")
-                    .span_label(*span1, "previous global allocator defined here")
-                    .emit();
+                self.sess.emit_err(NoMultipleGlobalAlloc { span2: *span2, span1: *span1 });
                 true
             }
             spans => !spans.is_empty(),
@@ -832,11 +823,10 @@ impl<'a> CrateLoader<'a> {
             if data.has_global_allocator() {
                 match global_allocator {
                     Some(other_crate) => {
-                        self.sess.err(&format!(
-                        "the `#[global_allocator]` in {} conflicts with global allocator in: {}",
-                        other_crate,
-                        data.name()
-                    ));
+                        self.sess.emit_err(ConflictingGlobalAlloc {
+                            crate_name: data.name(),
+                            other_crate_name: other_crate,
+                        });
                     }
                     None => global_allocator = Some(data.name()),
                 }
@@ -855,10 +845,7 @@ impl<'a> CrateLoader<'a> {
         if !self.sess.contains_name(&krate.attrs, sym::default_lib_allocator)
             && !self.cstore.iter_crate_data().any(|(_, data)| data.has_default_lib_allocator())
         {
-            self.sess.err(
-                "no global memory allocator found but one is required; link to std or add \
-                 `#[global_allocator]` to a static item that implements the GlobalAlloc trait",
-            );
+            self.sess.emit_err(GlobalAllocRequired);
         }
         self.cstore.allocator_kind = Some(AllocatorKind::Default);
     }
@@ -882,14 +869,11 @@ impl<'a> CrateLoader<'a> {
         for dep in self.cstore.crate_dependencies_in_reverse_postorder(krate) {
             let data = self.cstore.get_crate_data(dep);
             if needs_dep(&data) {
-                self.sess.err(&format!(
-                    "the crate `{}` cannot depend \
-                                        on a crate that needs {}, but \
-                                        it depends on `{}`",
-                    self.cstore.get_crate_data(krate).name(),
-                    what,
-                    data.name()
-                ));
+                self.sess.emit_err(NoTransitiveNeedsDep {
+                    crate_name: self.cstore.get_crate_data(krate).name(),
+                    needs_crate_name: what,
+                    deps_crate_name: data.name(),
+                });
             }
         }
 
diff --git a/compiler/rustc_metadata/src/dependency_format.rs b/compiler/rustc_metadata/src/dependency_format.rs
index b765c34f8..6112ec9e4 100644
--- a/compiler/rustc_metadata/src/dependency_format.rs
+++ b/compiler/rustc_metadata/src/dependency_format.rs
@@ -52,6 +52,10 @@
 //! than finding a number of solutions (there are normally quite a few).
 
 use crate::creader::CStore;
+use crate::errors::{
+    BadPanicStrategy, CrateDepMultiple, IncompatiblePanicInDropStrategy, LibRequired,
+    RequiredPanicStrategy, RlibRequired, TwoPanicRuntimes,
+};
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def_id::CrateNum;
@@ -136,11 +140,7 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
                 if src.rlib.is_some() {
                     continue;
                 }
-                sess.err(&format!(
-                    "crate `{}` required to be available in rlib format, \
-                                   but was not found in this form",
-                    tcx.crate_name(cnum)
-                ));
+                sess.emit_err(RlibRequired { crate_name: tcx.crate_name(cnum) });
             }
             return Vec::new();
         }
@@ -158,11 +158,11 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
         let name = tcx.crate_name(cnum);
         let src = tcx.used_crate_source(cnum);
         if src.dylib.is_some() {
-            tracing::info!("adding dylib: {}", name);
+            info!("adding dylib: {}", name);
             add_library(tcx, cnum, RequireDynamic, &mut formats);
             let deps = tcx.dylib_dependency_formats(cnum);
             for &(depnum, style) in deps.iter() {
-                tracing::info!("adding {:?}: {}", style, tcx.crate_name(depnum));
+                info!("adding {:?}: {}", style, tcx.crate_name(depnum));
                 add_library(tcx, depnum, style, &mut formats);
             }
         }
@@ -190,7 +190,7 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
             && tcx.dep_kind(cnum) == CrateDepKind::Explicit
         {
             assert!(src.rlib.is_some() || src.rmeta.is_some());
-            tracing::info!("adding staticlib: {}", tcx.crate_name(cnum));
+            info!("adding staticlib: {}", tcx.crate_name(cnum));
             add_library(tcx, cnum, RequireStatic, &mut formats);
             ret[cnum.as_usize() - 1] = Linkage::Static;
         }
@@ -224,12 +224,7 @@ fn calculate_type(tcx: TyCtxt<'_>, ty: CrateType) -> DependencyList {
                     Linkage::Static => "rlib",
                     _ => "dylib",
                 };
-                sess.err(&format!(
-                    "crate `{}` required to be available in {} format, \
-                                   but was not found in this form",
-                    tcx.crate_name(cnum),
-                    kind
-                ));
+                sess.emit_err(LibRequired { crate_name: tcx.crate_name(cnum), kind: kind });
             }
         }
     }
@@ -253,17 +248,7 @@ fn add_library(
             // This error is probably a little obscure, but I imagine that it
             // can be refined over time.
             if link2 != link || link == RequireStatic {
-                tcx.sess
-                    .struct_err(&format!(
-                        "cannot satisfy dependencies so `{}` only \
-                                              shows up once",
-                        tcx.crate_name(cnum)
-                    ))
-                    .help(
-                        "having upstream crates all available in one format \
-                           will likely make this go away",
-                    )
-                    .emit();
+                tcx.sess.emit_err(CrateDepMultiple { crate_name: tcx.crate_name(cnum) });
             }
         }
         None => {
@@ -360,11 +345,7 @@ fn verify_ok(tcx: TyCtxt<'_>, list: &[Linkage]) {
             if let Some((prev, _)) = panic_runtime {
                 let prev_name = tcx.crate_name(prev);
                 let cur_name = tcx.crate_name(cnum);
-                sess.err(&format!(
-                    "cannot link together two \
-                                   panic runtimes: {} and {}",
-                    prev_name, cur_name
-                ));
+                sess.emit_err(TwoPanicRuntimes { prev_name, cur_name });
             }
             panic_runtime = Some((
                 cnum,
@@ -384,13 +365,10 @@ fn verify_ok(tcx: TyCtxt<'_>, list: &[Linkage]) {
         // First up, validate that our selected panic runtime is indeed exactly
         // our same strategy.
         if found_strategy != desired_strategy {
-            sess.err(&format!(
-                "the linked panic runtime `{}` is \
-                               not compiled with this crate's \
-                               panic strategy `{}`",
-                tcx.crate_name(runtime_cnum),
-                desired_strategy.desc()
-            ));
+            sess.emit_err(BadPanicStrategy {
+                runtime: tcx.crate_name(runtime_cnum),
+                strategy: desired_strategy,
+            });
         }
 
         // Next up, verify that all other crates are compatible with this panic
@@ -407,28 +385,19 @@ fn verify_ok(tcx: TyCtxt<'_>, list: &[Linkage]) {
             }
 
             if let Some(found_strategy) = tcx.required_panic_strategy(cnum) && desired_strategy != found_strategy {
-                sess.err(&format!(
-                    "the crate `{}` requires \
-                               panic strategy `{}` which is \
-                               incompatible with this crate's \
-                               strategy of `{}`",
-                    tcx.crate_name(cnum),
-                    found_strategy.desc(),
-                    desired_strategy.desc()
-                ));
+                sess.emit_err(RequiredPanicStrategy {
+                    crate_name: tcx.crate_name(cnum),
+                    found_strategy,
+                    desired_strategy});
             }
 
             let found_drop_strategy = tcx.panic_in_drop_strategy(cnum);
             if tcx.sess.opts.unstable_opts.panic_in_drop != found_drop_strategy {
-                sess.err(&format!(
-                    "the crate `{}` is compiled with the \
-                               panic-in-drop strategy `{}` which is \
-                               incompatible with this crate's \
-                               strategy of `{}`",
-                    tcx.crate_name(cnum),
-                    found_drop_strategy.desc(),
-                    tcx.sess.opts.unstable_opts.panic_in_drop.desc()
-                ));
+                sess.emit_err(IncompatiblePanicInDropStrategy {
+                    crate_name: tcx.crate_name(cnum),
+                    found_strategy: found_drop_strategy,
+                    desired_strategy: tcx.sess.opts.unstable_opts.panic_in_drop,
+                });
             }
         }
     }
diff --git a/compiler/rustc_metadata/src/errors.rs b/compiler/rustc_metadata/src/errors.rs
new file mode 100644
index 000000000..7d63fad32
--- /dev/null
+++ b/compiler/rustc_metadata/src/errors.rs
@@ -0,0 +1,679 @@
+use std::{
+    io::Error,
+    path::{Path, PathBuf},
+};
+
+use rustc_errors::{error_code, ErrorGuaranteed};
+use rustc_macros::SessionDiagnostic;
+use rustc_session::{config, SessionDiagnostic};
+use rustc_span::{sym, Span, Symbol};
+use rustc_target::spec::{PanicStrategy, TargetTriple};
+
+use crate::locator::CrateFlavor;
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::rlib_required)]
+pub struct RlibRequired {
+    pub crate_name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::lib_required)]
+pub struct LibRequired<'a> {
+    pub crate_name: Symbol,
+    pub kind: &'a str,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::crate_dep_multiple)]
+#[help]
+pub struct CrateDepMultiple {
+    pub crate_name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::two_panic_runtimes)]
+pub struct TwoPanicRuntimes {
+    pub prev_name: Symbol,
+    pub cur_name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::bad_panic_strategy)]
+pub struct BadPanicStrategy {
+    pub runtime: Symbol,
+    pub strategy: PanicStrategy,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::required_panic_strategy)]
+pub struct RequiredPanicStrategy {
+    pub crate_name: Symbol,
+    pub found_strategy: PanicStrategy,
+    pub desired_strategy: PanicStrategy,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::incompatible_panic_in_drop_strategy)]
+pub struct IncompatiblePanicInDropStrategy {
+    pub crate_name: Symbol,
+    pub found_strategy: PanicStrategy,
+    pub desired_strategy: PanicStrategy,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::multiple_names_in_link)]
+pub struct MultipleNamesInLink {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::multiple_kinds_in_link)]
+pub struct MultipleKindsInLink {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::link_name_form)]
+pub struct LinkNameForm {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::link_kind_form)]
+pub struct LinkKindForm {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::link_modifiers_form)]
+pub struct LinkModifiersForm {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::link_cfg_form)]
+pub struct LinkCfgForm {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::wasm_import_form)]
+pub struct WasmImportForm {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::empty_link_name, code = "E0454")]
+pub struct EmptyLinkName {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::link_framework_apple, code = "E0455")]
+pub struct LinkFrameworkApple {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::framework_only_windows, code = "E0455")]
+pub struct FrameworkOnlyWindows {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::unknown_link_kind, code = "E0458")]
+pub struct UnknownLinkKind<'a> {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub kind: &'a str,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::multiple_link_modifiers)]
+pub struct MultipleLinkModifiers {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::multiple_cfgs)]
+pub struct MultipleCfgs {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::link_cfg_single_predicate)]
+pub struct LinkCfgSinglePredicate {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::multiple_wasm_import)]
+pub struct MultipleWasmImport {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::unexpected_link_arg)]
+pub struct UnexpectedLinkArg {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::invalid_link_modifier)]
+pub struct InvalidLinkModifier {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::multiple_modifiers)]
+pub struct MultipleModifiers<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub modifier: &'a str,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::bundle_needs_static)]
+pub struct BundleNeedsStatic {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::whole_archive_needs_static)]
+pub struct WholeArchiveNeedsStatic {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::as_needed_compatibility)]
+pub struct AsNeededCompatibility {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::unknown_link_modifier)]
+pub struct UnknownLinkModifier<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub modifier: &'a str,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::incompatible_wasm_link)]
+pub struct IncompatibleWasmLink {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::link_requires_name, code = "E0459")]
+pub struct LinkRequiresName {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::raw_dylib_no_nul)]
+pub struct RawDylibNoNul {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::link_ordinal_raw_dylib)]
+pub struct LinkOrdinalRawDylib {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::lib_framework_apple)]
+pub struct LibFrameworkApple;
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::empty_renaming_target)]
+pub struct EmptyRenamingTarget<'a> {
+    pub lib_name: &'a str,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::renaming_no_link)]
+pub struct RenamingNoLink<'a> {
+    pub lib_name: &'a str,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::multiple_renamings)]
+pub struct MultipleRenamings<'a> {
+    pub lib_name: &'a str,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::no_link_mod_override)]
+pub struct NoLinkModOverride {
+    #[primary_span]
+    pub span: Option<Span>,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::unsupported_abi_i686)]
+pub struct UnsupportedAbiI686 {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::unsupported_abi)]
+pub struct UnsupportedAbi {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::fail_create_file_encoder)]
+pub struct FailCreateFileEncoder {
+    pub err: Error,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::fail_seek_file)]
+pub struct FailSeekFile {
+    pub err: Error,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::fail_write_file)]
+pub struct FailWriteFile {
+    pub err: Error,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::crate_not_panic_runtime)]
+pub struct CrateNotPanicRuntime {
+    pub crate_name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::no_panic_strategy)]
+pub struct NoPanicStrategy {
+    pub crate_name: Symbol,
+    pub strategy: PanicStrategy,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::profiler_builtins_needs_core)]
+pub struct ProfilerBuiltinsNeedsCore;
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::not_profiler_runtime)]
+pub struct NotProfilerRuntime {
+    pub crate_name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::no_multiple_global_alloc)]
+pub struct NoMultipleGlobalAlloc {
+    #[primary_span]
+    #[label]
+    pub span2: Span,
+    #[label(metadata::prev_global_alloc)]
+    pub span1: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::conflicting_global_alloc)]
+pub struct ConflictingGlobalAlloc {
+    pub crate_name: Symbol,
+    pub other_crate_name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::global_alloc_required)]
+pub struct GlobalAllocRequired;
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::no_transitive_needs_dep)]
+pub struct NoTransitiveNeedsDep<'a> {
+    pub crate_name: Symbol,
+    pub needs_crate_name: &'a str,
+    pub deps_crate_name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::failed_write_error)]
+pub struct FailedWriteError {
+    pub filename: PathBuf,
+    pub err: Error,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::missing_native_library)]
+pub struct MissingNativeLibrary<'a> {
+    pub libname: &'a str,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::failed_create_tempdir)]
+pub struct FailedCreateTempdir {
+    pub err: Error,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::failed_create_file)]
+pub struct FailedCreateFile<'a> {
+    pub filename: &'a Path,
+    pub err: Error,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::failed_create_encoded_metadata)]
+pub struct FailedCreateEncodedMetadata {
+    pub err: Error,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::non_ascii_name)]
+pub struct NonAsciiName {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::extern_location_not_exist)]
+pub struct ExternLocationNotExist<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub location: &'a Path,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::extern_location_not_file)]
+pub struct ExternLocationNotFile<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub location: &'a Path,
+}
+
+pub(crate) struct MultipleCandidates {
+    pub span: Span,
+    pub flavor: CrateFlavor,
+    pub crate_name: Symbol,
+    pub candidates: Vec<PathBuf>,
+}
+
+impl SessionDiagnostic<'_> for MultipleCandidates {
+    fn into_diagnostic(
+        self,
+        handler: &'_ rustc_errors::Handler,
+    ) -> rustc_errors::DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = handler.struct_err(rustc_errors::fluent::metadata::multiple_candidates);
+        diag.set_arg("crate_name", self.crate_name);
+        diag.set_arg("flavor", self.flavor);
+        diag.code(error_code!(E0465));
+        diag.set_span(self.span);
+        for (i, candidate) in self.candidates.iter().enumerate() {
+            diag.span_note(self.span, &format!("candidate #{}: {}", i + 1, candidate.display()));
+        }
+        diag
+    }
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::multiple_matching_crates, code = "E0464")]
+#[note]
+pub struct MultipleMatchingCrates {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub candidates: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::symbol_conflicts_current, code = "E0519")]
+pub struct SymbolConflictsCurrent {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::symbol_conflicts_others, code = "E0523")]
+pub struct SymbolConflictsOthers {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::stable_crate_id_collision)]
+pub struct StableCrateIdCollision {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name0: Symbol,
+    pub crate_name1: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::dl_error)]
+pub struct DlError {
+    #[primary_span]
+    pub span: Span,
+    pub err: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::newer_crate_version, code = "E0460")]
+#[note]
+#[note(metadata::found_crate_versions)]
+pub struct NewerCrateVersion {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub add_info: String,
+    pub found_crates: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::no_crate_with_triple, code = "E0461")]
+#[note(metadata::found_crate_versions)]
+pub struct NoCrateWithTriple<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub locator_triple: &'a str,
+    pub add_info: String,
+    pub found_crates: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::found_staticlib, code = "E0462")]
+#[note(metadata::found_crate_versions)]
+#[help]
+pub struct FoundStaticlib {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub add_info: String,
+    pub found_crates: String,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::incompatible_rustc, code = "E0514")]
+#[note(metadata::found_crate_versions)]
+#[help]
+pub struct IncompatibleRustc {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub add_info: String,
+    pub found_crates: String,
+    pub rustc_version: String,
+}
+
+pub struct InvalidMetadataFiles {
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub add_info: String,
+    pub crate_rejections: Vec<String>,
+}
+
+impl SessionDiagnostic<'_> for InvalidMetadataFiles {
+    fn into_diagnostic(
+        self,
+        handler: &'_ rustc_errors::Handler,
+    ) -> rustc_errors::DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = handler.struct_err(rustc_errors::fluent::metadata::invalid_meta_files);
+        diag.set_arg("crate_name", self.crate_name);
+        diag.set_arg("add_info", self.add_info);
+        diag.code(error_code!(E0786));
+        diag.set_span(self.span);
+        for crate_rejection in self.crate_rejections {
+            diag.note(crate_rejection);
+        }
+        diag
+    }
+}
+
+pub struct CannotFindCrate {
+    pub span: Span,
+    pub crate_name: Symbol,
+    pub add_info: String,
+    pub missing_core: bool,
+    pub current_crate: String,
+    pub is_nightly_build: bool,
+    pub profiler_runtime: Symbol,
+    pub locator_triple: TargetTriple,
+}
+
+impl SessionDiagnostic<'_> for CannotFindCrate {
+    fn into_diagnostic(
+        self,
+        handler: &'_ rustc_errors::Handler,
+    ) -> rustc_errors::DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = handler.struct_err(rustc_errors::fluent::metadata::cannot_find_crate);
+        diag.set_arg("crate_name", self.crate_name);
+        diag.set_arg("current_crate", self.current_crate);
+        diag.set_arg("add_info", self.add_info);
+        diag.set_arg("locator_triple", self.locator_triple.triple());
+        diag.code(error_code!(E0463));
+        diag.set_span(self.span);
+        if (self.crate_name == sym::std || self.crate_name == sym::core)
+            && self.locator_triple != TargetTriple::from_triple(config::host_triple())
+        {
+            if self.missing_core {
+                diag.note(rustc_errors::fluent::metadata::target_not_installed);
+            } else {
+                diag.note(rustc_errors::fluent::metadata::target_no_std_support);
+            }
+            // NOTE: this suggests using rustup, even though the user may not have it installed.
+            // That's because they could choose to install it; or this may give them a hint which
+            // target they need to install from their distro.
+            if self.missing_core {
+                diag.help(rustc_errors::fluent::metadata::consider_downloading_target);
+            }
+            // Suggest using #![no_std]. #[no_core] is unstable and not really supported anyway.
+            // NOTE: this is a dummy span if `extern crate std` was injected by the compiler.
+            // If it's not a dummy, that means someone added `extern crate std` explicitly and
+            // `#![no_std]` won't help.
+            if !self.missing_core && self.span.is_dummy() {
+                diag.note(rustc_errors::fluent::metadata::std_required);
+            }
+            if self.is_nightly_build {
+                diag.help(rustc_errors::fluent::metadata::consider_building_std);
+            }
+        } else if self.crate_name == self.profiler_runtime {
+            diag.note(rustc_errors::fluent::metadata::compiler_missing_profiler);
+        } else if self.crate_name.as_str().starts_with("rustc_") {
+            diag.help(rustc_errors::fluent::metadata::install_missing_components);
+        }
+        diag.span_label(self.span, rustc_errors::fluent::metadata::cant_find_crate);
+        diag
+    }
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::no_dylib_plugin, code = "E0457")]
+pub struct NoDylibPlugin {
+    #[primary_span]
+    pub span: Span,
+    pub crate_name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::crate_location_unknown_type)]
+pub struct CrateLocationUnknownType<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub path: &'a Path,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::lib_filename_form)]
+pub struct LibFilenameForm<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub dll_prefix: &'a str,
+    pub dll_suffix: &'a str,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::multiple_import_name_type)]
+pub struct MultipleImportNameType {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::import_name_type_form)]
+pub struct ImportNameTypeForm {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::import_name_type_x86)]
+pub struct ImportNameTypeX86 {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::unknown_import_name_type)]
+pub struct UnknownImportNameType<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub import_name_type: &'a str,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(metadata::import_name_type_raw)]
+pub struct ImportNameTypeRaw {
+    #[primary_span]
+    pub span: Span,
+}
diff --git a/compiler/rustc_metadata/src/fs.rs b/compiler/rustc_metadata/src/fs.rs
index e6072901a..f360a5864 100644
--- a/compiler/rustc_metadata/src/fs.rs
+++ b/compiler/rustc_metadata/src/fs.rs
@@ -1,3 +1,6 @@
+use crate::errors::{
+    FailedCreateEncodedMetadata, FailedCreateFile, FailedCreateTempdir, FailedWriteError,
+};
 use crate::{encode_metadata, EncodedMetadata};
 
 use rustc_data_structures::temp_dir::MaybeTempDir;
@@ -23,8 +26,8 @@ pub fn emit_metadata(sess: &Session, metadata: &[u8], tmpdir: &MaybeTempDir) ->
     let out_filename = tmpdir.as_ref().join(METADATA_FILENAME);
     let result = fs::write(&out_filename, metadata);
 
-    if let Err(e) = result {
-        sess.fatal(&format!("failed to write {}: {}", out_filename.display(), e));
+    if let Err(err) = result {
+        sess.emit_fatal(FailedWriteError { filename: out_filename, err });
     }
 
     out_filename
@@ -65,7 +68,7 @@ pub fn encode_and_write_metadata(
     let metadata_tmpdir = TempFileBuilder::new()
         .prefix("rmeta")
         .tempdir_in(out_filename.parent().unwrap_or_else(|| Path::new("")))
-        .unwrap_or_else(|err| tcx.sess.fatal(&format!("couldn't create a temp dir: {}", err)));
+        .unwrap_or_else(|err| tcx.sess.emit_fatal(FailedCreateTempdir { err }));
     let metadata_tmpdir = MaybeTempDir::new(metadata_tmpdir, tcx.sess.opts.cg.save_temps);
     let metadata_filename = metadata_tmpdir.as_ref().join(METADATA_FILENAME);
 
@@ -73,12 +76,8 @@ pub fn encode_and_write_metadata(
     // This simplifies the creation of the output `out_filename` when requested.
     match metadata_kind {
         MetadataKind::None => {
-            std::fs::File::create(&metadata_filename).unwrap_or_else(|e| {
-                tcx.sess.fatal(&format!(
-                    "failed to create the file {}: {}",
-                    metadata_filename.display(),
-                    e
-                ))
+            std::fs::File::create(&metadata_filename).unwrap_or_else(|err| {
+                tcx.sess.emit_fatal(FailedCreateFile { filename: &metadata_filename, err });
             });
         }
         MetadataKind::Uncompressed | MetadataKind::Compressed => {
@@ -93,8 +92,8 @@ pub fn encode_and_write_metadata(
     // this file always exists.
     let need_metadata_file = tcx.sess.opts.output_types.contains_key(&OutputType::Metadata);
     let (metadata_filename, metadata_tmpdir) = if need_metadata_file {
-        if let Err(e) = non_durable_rename(&metadata_filename, &out_filename) {
-            tcx.sess.fatal(&format!("failed to write {}: {}", out_filename.display(), e));
+        if let Err(err) = non_durable_rename(&metadata_filename, &out_filename) {
+            tcx.sess.emit_fatal(FailedWriteError { filename: out_filename, err });
         }
         if tcx.sess.opts.json_artifact_notifications {
             tcx.sess
@@ -109,8 +108,8 @@ pub fn encode_and_write_metadata(
 
     // Load metadata back to memory: codegen may need to include it in object files.
     let metadata =
-        EncodedMetadata::from_path(metadata_filename, metadata_tmpdir).unwrap_or_else(|e| {
-            tcx.sess.fatal(&format!("failed to create encoded metadata from file: {}", e))
+        EncodedMetadata::from_path(metadata_filename, metadata_tmpdir).unwrap_or_else(|err| {
+            tcx.sess.emit_fatal(FailedCreateEncodedMetadata { err });
         });
 
     let need_metadata_module = metadata_kind == MetadataKind::Compressed;
diff --git a/compiler/rustc_metadata/src/lib.rs b/compiler/rustc_metadata/src/lib.rs
index 6440f3e39..6f5604b7e 100644
--- a/compiler/rustc_metadata/src/lib.rs
+++ b/compiler/rustc_metadata/src/lib.rs
@@ -2,10 +2,10 @@
 #![feature(decl_macro)]
 #![feature(drain_filter)]
 #![feature(generators)]
-#![feature(generic_associated_types)]
+#![cfg_attr(bootstrap, feature(generic_associated_types))]
 #![feature(iter_from_generator)]
 #![feature(let_chains)]
-#![feature(let_else)]
+#![cfg_attr(bootstrap, feature(let_else))]
 #![feature(once_cell)]
 #![feature(proc_macro_internals)]
 #![feature(macro_metavar_expr)]
@@ -16,6 +16,8 @@
 #![feature(never_type)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
 
 extern crate proc_macro;
 
@@ -26,6 +28,9 @@ extern crate rustc_middle;
 #[macro_use]
 extern crate rustc_data_structures;
 
+#[macro_use]
+extern crate tracing;
+
 pub use rmeta::{provide, provide_extern};
 
 mod dependency_format;
@@ -34,8 +39,10 @@ mod native_libs;
 mod rmeta;
 
 pub mod creader;
+pub mod errors;
 pub mod fs;
 pub mod locator;
 
 pub use fs::{emit_metadata, METADATA_FILENAME};
+pub use native_libs::find_native_static_library;
 pub use rmeta::{encode_metadata, EncodedMetadata, METADATA_HEADER};
diff --git a/compiler/rustc_metadata/src/locator.rs b/compiler/rustc_metadata/src/locator.rs
index 2c1c84b0b..35f9ef92a 100644
--- a/compiler/rustc_metadata/src/locator.rs
+++ b/compiler/rustc_metadata/src/locator.rs
@@ -213,6 +213,13 @@
 //! metadata::locator or metadata::creader for all the juicy details!
 
 use crate::creader::Library;
+use crate::errors::{
+    CannotFindCrate, CrateLocationUnknownType, DlError, ExternLocationNotExist,
+    ExternLocationNotFile, FoundStaticlib, IncompatibleRustc, InvalidMetadataFiles,
+    LibFilenameForm, MultipleCandidates, MultipleMatchingCrates, NewerCrateVersion,
+    NoCrateWithTriple, NoDylibPlugin, NonAsciiName, StableCrateIdCollision, SymbolConflictsCurrent,
+    SymbolConflictsOthers,
+};
 use crate::rmeta::{rustc_version, MetadataBlob, METADATA_HEADER};
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
@@ -220,23 +227,23 @@ use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::owning_ref::OwningRef;
 use rustc_data_structures::svh::Svh;
 use rustc_data_structures::sync::MetadataRef;
-use rustc_errors::{struct_span_err, FatalError};
+use rustc_errors::{DiagnosticArgValue, FatalError, IntoDiagnosticArg};
 use rustc_session::config::{self, CrateType};
 use rustc_session::cstore::{CrateSource, MetadataLoader};
 use rustc_session::filesearch::FileSearch;
 use rustc_session::search_paths::PathKind;
 use rustc_session::utils::CanonicalizedPath;
 use rustc_session::Session;
-use rustc_span::symbol::{sym, Symbol};
+use rustc_span::symbol::Symbol;
 use rustc_span::Span;
 use rustc_target::spec::{Target, TargetTriple};
 
 use snap::read::FrameDecoder;
+use std::borrow::Cow;
 use std::fmt::Write as _;
 use std::io::{Read, Result as IoResult, Write};
 use std::path::{Path, PathBuf};
 use std::{cmp, fmt, fs};
-use tracing::{debug, info};
 
 #[derive(Clone)]
 pub(crate) struct CrateLocator<'a> {
@@ -288,6 +295,16 @@ impl fmt::Display for CrateFlavor {
     }
 }
 
+impl IntoDiagnosticArg for CrateFlavor {
+    fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
+        match self {
+            CrateFlavor::Rlib => DiagnosticArgValue::Str(Cow::Borrowed("rlib")),
+            CrateFlavor::Rmeta => DiagnosticArgValue::Str(Cow::Borrowed("rmeta")),
+            CrateFlavor::Dylib => DiagnosticArgValue::Str(Cow::Borrowed("dylib")),
+        }
+    }
+}
+
 impl<'a> CrateLocator<'a> {
     pub(crate) fn new(
         sess: &'a Session,
@@ -938,41 +955,20 @@ impl fmt::Display for MetadataError<'_> {
 
 impl CrateError {
     pub(crate) fn report(self, sess: &Session, span: Span, missing_core: bool) {
-        let mut diag = match self {
-            CrateError::NonAsciiName(crate_name) => sess.struct_span_err(
-                span,
-                &format!("cannot load a crate with a non-ascii name `{}`", crate_name),
-            ),
-            CrateError::ExternLocationNotExist(crate_name, loc) => sess.struct_span_err(
-                span,
-                &format!("extern location for {} does not exist: {}", crate_name, loc.display()),
-            ),
-            CrateError::ExternLocationNotFile(crate_name, loc) => sess.struct_span_err(
-                span,
-                &format!("extern location for {} is not a file: {}", crate_name, loc.display()),
-            ),
+        match self {
+            CrateError::NonAsciiName(crate_name) => {
+                sess.emit_err(NonAsciiName { span, crate_name });
+            }
+            CrateError::ExternLocationNotExist(crate_name, loc) => {
+                sess.emit_err(ExternLocationNotExist { span, crate_name, location: &loc });
+            }
+            CrateError::ExternLocationNotFile(crate_name, loc) => {
+                sess.emit_err(ExternLocationNotFile { span, crate_name, location: &loc });
+            }
             CrateError::MultipleCandidates(crate_name, flavor, candidates) => {
-                let mut err = struct_span_err!(
-                    sess,
-                    span,
-                    E0465,
-                    "multiple {} candidates for `{}` found",
-                    flavor,
-                    crate_name,
-                );
-                for (i, candidate) in candidates.iter().enumerate() {
-                    err.span_note(span, &format!("candidate #{}: {}", i + 1, candidate.display()));
-                }
-                err
+                sess.emit_err(MultipleCandidates { span, flavor: flavor, crate_name, candidates });
             }
             CrateError::MultipleMatchingCrates(crate_name, libraries) => {
-                let mut err = struct_span_err!(
-                    sess,
-                    span,
-                    E0464,
-                    "multiple matching crates for `{}`",
-                    crate_name
-                );
                 let mut libraries: Vec<_> = libraries.into_values().collect();
                 // Make ordering of candidates deterministic.
                 // This has to `clone()` to work around lifetime restrictions with `sort_by_key()`.
@@ -1000,223 +996,142 @@ impl CrateError {
                         s
                     })
                     .collect::<String>();
-                err.note(&format!("candidates:{}", candidates));
-                err
+                sess.emit_err(MultipleMatchingCrates { span, crate_name, candidates });
+            }
+            CrateError::SymbolConflictsCurrent(root_name) => {
+                sess.emit_err(SymbolConflictsCurrent { span, crate_name: root_name });
+            }
+            CrateError::SymbolConflictsOthers(root_name) => {
+                sess.emit_err(SymbolConflictsOthers { span, crate_name: root_name });
             }
-            CrateError::SymbolConflictsCurrent(root_name) => struct_span_err!(
-                sess,
-                span,
-                E0519,
-                "the current crate is indistinguishable from one of its dependencies: it has the \
-                 same crate-name `{}` and was compiled with the same `-C metadata` arguments. \
-                 This will result in symbol conflicts between the two.",
-                root_name,
-            ),
-            CrateError::SymbolConflictsOthers(root_name) => struct_span_err!(
-                sess,
-                span,
-                E0523,
-                "found two different crates with name `{}` that are not distinguished by differing \
-                 `-C metadata`. This will result in symbol conflicts between the two.",
-                root_name,
-            ),
             CrateError::StableCrateIdCollision(crate_name0, crate_name1) => {
-                let msg = format!(
-                    "found crates (`{}` and `{}`) with colliding StableCrateId values.",
-                    crate_name0, crate_name1
-                );
-                sess.struct_span_err(span, &msg)
+                sess.emit_err(StableCrateIdCollision {
+                    span,
+                    crate_name0: crate_name0,
+                    crate_name1: crate_name1,
+                });
+            }
+            CrateError::DlOpen(s) | CrateError::DlSym(s) => {
+                sess.emit_err(DlError { span, err: s });
             }
-            CrateError::DlOpen(s) | CrateError::DlSym(s) => sess.struct_span_err(span, &s),
             CrateError::LocatorCombined(locator) => {
                 let crate_name = locator.crate_name;
-                let add = match &locator.root {
+                let add_info = match &locator.root {
                     None => String::new(),
                     Some(r) => format!(" which `{}` depends on", r.name),
                 };
-                let mut msg = "the following crate versions were found:".to_string();
-                let mut err = if !locator.crate_rejections.via_hash.is_empty() {
-                    let mut err = struct_span_err!(
-                        sess,
-                        span,
-                        E0460,
-                        "found possibly newer version of crate `{}`{}",
-                        crate_name,
-                        add,
-                    );
-                    err.note("perhaps that crate needs to be recompiled?");
+                // FIXME: There are no tests for CrateLocationUnknownType or LibFilenameForm
+                if !locator.crate_rejections.via_filename.is_empty() {
+                    let mismatches = locator.crate_rejections.via_filename.iter();
+                    for CrateMismatch { path, .. } in mismatches {
+                        sess.emit_err(CrateLocationUnknownType { span, path: &path });
+                        sess.emit_err(LibFilenameForm {
+                            span,
+                            dll_prefix: &locator.dll_prefix,
+                            dll_suffix: &locator.dll_suffix,
+                        });
+                    }
+                }
+                let mut found_crates = String::new();
+                if !locator.crate_rejections.via_hash.is_empty() {
                     let mismatches = locator.crate_rejections.via_hash.iter();
                     for CrateMismatch { path, .. } in mismatches {
-                        msg.push_str(&format!("\ncrate `{}`: {}", crate_name, path.display()));
+                        found_crates.push_str(&format!(
+                            "\ncrate `{}`: {}",
+                            crate_name,
+                            path.display()
+                        ));
                     }
                     if let Some(r) = locator.root {
                         for path in r.source.paths() {
-                            msg.push_str(&format!("\ncrate `{}`: {}", r.name, path.display()));
+                            found_crates.push_str(&format!(
+                                "\ncrate `{}`: {}",
+                                r.name,
+                                path.display()
+                            ));
                         }
                     }
-                    err.note(&msg);
-                    err
-                } else if !locator.crate_rejections.via_triple.is_empty() {
-                    let mut err = struct_span_err!(
-                        sess,
+                    sess.emit_err(NewerCrateVersion {
                         span,
-                        E0461,
-                        "couldn't find crate `{}` with expected target triple {}{}",
-                        crate_name,
-                        locator.triple,
-                        add,
-                    );
+                        crate_name: crate_name,
+                        add_info,
+                        found_crates,
+                    });
+                } else if !locator.crate_rejections.via_triple.is_empty() {
                     let mismatches = locator.crate_rejections.via_triple.iter();
                     for CrateMismatch { path, got } in mismatches {
-                        msg.push_str(&format!(
+                        found_crates.push_str(&format!(
                             "\ncrate `{}`, target triple {}: {}",
                             crate_name,
                             got,
                             path.display(),
                         ));
                     }
-                    err.note(&msg);
-                    err
-                } else if !locator.crate_rejections.via_kind.is_empty() {
-                    let mut err = struct_span_err!(
-                        sess,
+                    sess.emit_err(NoCrateWithTriple {
                         span,
-                        E0462,
-                        "found staticlib `{}` instead of rlib or dylib{}",
-                        crate_name,
-                        add,
-                    );
-                    err.help("please recompile that crate using --crate-type lib");
+                        crate_name: crate_name,
+                        locator_triple: locator.triple.triple(),
+                        add_info,
+                        found_crates,
+                    });
+                } else if !locator.crate_rejections.via_kind.is_empty() {
                     let mismatches = locator.crate_rejections.via_kind.iter();
                     for CrateMismatch { path, .. } in mismatches {
-                        msg.push_str(&format!("\ncrate `{}`: {}", crate_name, path.display()));
+                        found_crates.push_str(&format!(
+                            "\ncrate `{}`: {}",
+                            crate_name,
+                            path.display()
+                        ));
                     }
-                    err.note(&msg);
-                    err
+                    sess.emit_err(FoundStaticlib { span, crate_name, add_info, found_crates });
                 } else if !locator.crate_rejections.via_version.is_empty() {
-                    let mut err = struct_span_err!(
-                        sess,
-                        span,
-                        E0514,
-                        "found crate `{}` compiled by an incompatible version of rustc{}",
-                        crate_name,
-                        add,
-                    );
-                    err.help(&format!(
-                        "please recompile that crate using this compiler ({}) \
-                         (consider running `cargo clean` first)",
-                        rustc_version(),
-                    ));
                     let mismatches = locator.crate_rejections.via_version.iter();
                     for CrateMismatch { path, got } in mismatches {
-                        msg.push_str(&format!(
+                        found_crates.push_str(&format!(
                             "\ncrate `{}` compiled by {}: {}",
                             crate_name,
                             got,
                             path.display(),
                         ));
                     }
-                    err.note(&msg);
-                    err
-                } else if !locator.crate_rejections.via_invalid.is_empty() {
-                    let mut err = struct_span_err!(
-                        sess,
+                    sess.emit_err(IncompatibleRustc {
                         span,
-                        E0786,
-                        "found invalid metadata files for crate `{}`{}",
                         crate_name,
-                        add,
-                    );
+                        add_info,
+                        found_crates,
+                        rustc_version: rustc_version(),
+                    });
+                } else if !locator.crate_rejections.via_invalid.is_empty() {
+                    let mut crate_rejections = Vec::new();
                     for CrateMismatch { path: _, got } in locator.crate_rejections.via_invalid {
-                        err.note(&got);
+                        crate_rejections.push(got);
                     }
-                    err
+                    sess.emit_err(InvalidMetadataFiles {
+                        span,
+                        crate_name,
+                        add_info,
+                        crate_rejections,
+                    });
                 } else {
-                    let mut err = struct_span_err!(
-                        sess,
+                    sess.emit_err(CannotFindCrate {
                         span,
-                        E0463,
-                        "can't find crate for `{}`{}",
                         crate_name,
-                        add,
-                    );
-
-                    if (crate_name == sym::std || crate_name == sym::core)
-                        && locator.triple != TargetTriple::from_triple(config::host_triple())
-                    {
-                        if missing_core {
-                            err.note(&format!(
-                                "the `{}` target may not be installed",
-                                locator.triple
-                            ));
-                        } else {
-                            err.note(&format!(
-                                "the `{}` target may not support the standard library",
-                                locator.triple
-                            ));
-                        }
-                        // NOTE: this suggests using rustup, even though the user may not have it installed.
-                        // That's because they could choose to install it; or this may give them a hint which
-                        // target they need to install from their distro.
-                        if missing_core {
-                            err.help(&format!(
-                                "consider downloading the target with `rustup target add {}`",
-                                locator.triple
-                            ));
-                        }
-                        // Suggest using #![no_std]. #[no_core] is unstable and not really supported anyway.
-                        // NOTE: this is a dummy span if `extern crate std` was injected by the compiler.
-                        // If it's not a dummy, that means someone added `extern crate std` explicitly and `#![no_std]` won't help.
-                        if !missing_core && span.is_dummy() {
-                            let current_crate =
-                                sess.opts.crate_name.as_deref().unwrap_or("<unknown>");
-                            err.note(&format!(
-                                "`std` is required by `{}` because it does not declare `#![no_std]`",
-                                current_crate
-                            ));
-                        }
-                        if sess.is_nightly_build() {
-                            err.help("consider building the standard library from source with `cargo build -Zbuild-std`");
-                        }
-                    } else if crate_name
-                        == Symbol::intern(&sess.opts.unstable_opts.profiler_runtime)
-                    {
-                        err.note("the compiler may have been built without the profiler runtime");
-                    } else if crate_name.as_str().starts_with("rustc_") {
-                        err.help(
-                            "maybe you need to install the missing components with: \
-                             `rustup component add rust-src rustc-dev llvm-tools-preview`",
-                        );
-                    }
-                    err.span_label(span, "can't find crate");
-                    err
-                };
-
-                if !locator.crate_rejections.via_filename.is_empty() {
-                    let mismatches = locator.crate_rejections.via_filename.iter();
-                    for CrateMismatch { path, .. } in mismatches {
-                        err.note(&format!(
-                            "extern location for {} is of an unknown type: {}",
-                            crate_name,
-                            path.display(),
-                        ))
-                        .help(&format!(
-                            "file name should be lib*.rlib or {}*.{}",
-                            locator.dll_prefix, locator.dll_suffix
-                        ));
-                    }
+                        add_info,
+                        missing_core,
+                        current_crate: sess
+                            .opts
+                            .crate_name
+                            .clone()
+                            .unwrap_or("<unknown>".to_string()),
+                        is_nightly_build: sess.is_nightly_build(),
+                        profiler_runtime: Symbol::intern(&sess.opts.unstable_opts.profiler_runtime),
+                        locator_triple: locator.triple,
+                    });
                 }
-                err
             }
-            CrateError::NonDylibPlugin(crate_name) => struct_span_err!(
-                sess,
-                span,
-                E0457,
-                "plugin `{}` only found in rlib format, but must be available in dylib format",
-                crate_name,
-            ),
-        };
-
-        diag.emit();
+            CrateError::NonDylibPlugin(crate_name) => {
+                sess.emit_err(NoDylibPlugin { span, crate_name });
+            }
+        }
     }
 }
diff --git a/compiler/rustc_metadata/src/native_libs.rs b/compiler/rustc_metadata/src/native_libs.rs
index 9f6079ecb..257741c13 100644
--- a/compiler/rustc_metadata/src/native_libs.rs
+++ b/compiler/rustc_metadata/src/native_libs.rs
@@ -1,17 +1,83 @@
 use rustc_ast::{NestedMetaItem, CRATE_NODE_ID};
 use rustc_attr as attr;
 use rustc_data_structures::fx::FxHashSet;
-use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_middle::ty::{List, ParamEnv, ParamEnvAnd, Ty, TyCtxt};
-use rustc_session::cstore::{DllCallingConvention, DllImport, NativeLib};
+use rustc_session::config::CrateType;
+use rustc_session::cstore::{DllCallingConvention, DllImport, NativeLib, PeImportNameType};
 use rustc_session::parse::feature_err;
+use rustc_session::search_paths::PathKind;
 use rustc_session::utils::NativeLibKind;
 use rustc_session::Session;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_target::spec::abi::Abi;
 
+use crate::errors::{
+    AsNeededCompatibility, BundleNeedsStatic, EmptyLinkName, EmptyRenamingTarget,
+    FrameworkOnlyWindows, ImportNameTypeForm, ImportNameTypeRaw, ImportNameTypeX86,
+    IncompatibleWasmLink, InvalidLinkModifier, LibFrameworkApple, LinkCfgForm,
+    LinkCfgSinglePredicate, LinkFrameworkApple, LinkKindForm, LinkModifiersForm, LinkNameForm,
+    LinkOrdinalRawDylib, LinkRequiresName, MissingNativeLibrary, MultipleCfgs,
+    MultipleImportNameType, MultipleKindsInLink, MultipleLinkModifiers, MultipleModifiers,
+    MultipleNamesInLink, MultipleRenamings, MultipleWasmImport, NoLinkModOverride, RawDylibNoNul,
+    RenamingNoLink, UnexpectedLinkArg, UnknownImportNameType, UnknownLinkKind, UnknownLinkModifier,
+    UnsupportedAbi, UnsupportedAbiI686, WasmImportForm, WholeArchiveNeedsStatic,
+};
+
+use std::path::PathBuf;
+
+pub fn find_native_static_library(
+    name: &str,
+    verbatim: Option<bool>,
+    search_paths: &[PathBuf],
+    sess: &Session,
+) -> PathBuf {
+    let verbatim = verbatim.unwrap_or(false);
+    // On Windows, static libraries sometimes show up as libfoo.a and other
+    // times show up as foo.lib
+    let oslibname = if verbatim {
+        name.to_string()
+    } else {
+        format!("{}{}{}", sess.target.staticlib_prefix, name, sess.target.staticlib_suffix)
+    };
+    let unixlibname = format!("lib{}.a", name);
+
+    for path in search_paths {
+        let test = path.join(&oslibname);
+        if test.exists() {
+            return test;
+        }
+        if oslibname != unixlibname {
+            let test = path.join(&unixlibname);
+            if test.exists() {
+                return test;
+            }
+        }
+    }
+    sess.emit_fatal(MissingNativeLibrary { libname: name });
+}
+
+fn find_bundled_library(
+    name: Option<Symbol>,
+    verbatim: Option<bool>,
+    kind: NativeLibKind,
+    sess: &Session,
+) -> Option<Symbol> {
+    if sess.opts.unstable_opts.packed_bundled_libs &&
+            sess.crate_types().iter().any(|ct| ct == &CrateType::Rlib || ct == &CrateType::Staticlib) &&
+            let NativeLibKind::Static { bundle: Some(true) | None, .. } = kind {
+        find_native_static_library(
+            name.unwrap().as_str(),
+            verbatim,
+            &sess.target_filesearch(PathKind::Native).search_path_dirs(),
+            sess,
+        ).file_name().and_then(|s| s.to_str()).map(Symbol::intern)
+    } else {
+        None
+    }
+}
+
 pub(crate) fn collect(tcx: TyCtxt<'_>) -> Vec<NativeLib> {
     let mut collector = Collector { tcx, libs: Vec::new() };
     for id in tcx.hir().items() {
@@ -61,36 +127,31 @@ impl<'tcx> Collector<'tcx> {
             let mut modifiers = None;
             let mut cfg = None;
             let mut wasm_import_module = None;
+            let mut import_name_type = None;
             for item in items.iter() {
                 match item.name_or_empty() {
                     sym::name => {
                         if name.is_some() {
-                            let msg = "multiple `name` arguments in a single `#[link]` attribute";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(MultipleNamesInLink { span: item.span() });
                             continue;
                         }
                         let Some(link_name) = item.value_str() else {
-                            let msg = "link name must be of the form `name = \"string\"`";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(LinkNameForm { span: item.span() });
                             continue;
                         };
                         let span = item.name_value_literal_span().unwrap();
                         if link_name.is_empty() {
-                            struct_span_err!(sess, span, E0454, "link name must not be empty")
-                                .span_label(span, "empty link name")
-                                .emit();
+                            sess.emit_err(EmptyLinkName { span });
                         }
                         name = Some((link_name, span));
                     }
                     sym::kind => {
                         if kind.is_some() {
-                            let msg = "multiple `kind` arguments in a single `#[link]` attribute";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(MultipleKindsInLink { span: item.span() });
                             continue;
                         }
                         let Some(link_kind) = item.value_str() else {
-                            let msg = "link kind must be of the form `kind = \"string\"`";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(LinkKindForm { span: item.span() });
                             continue;
                         };
 
@@ -100,44 +161,26 @@ impl<'tcx> Collector<'tcx> {
                             "dylib" => NativeLibKind::Dylib { as_needed: None },
                             "framework" => {
                                 if !sess.target.is_like_osx {
-                                    struct_span_err!(
-                                        sess,
-                                        span,
-                                        E0455,
-                                        "link kind `framework` is only supported on Apple targets"
-                                    )
-                                    .emit();
+                                    sess.emit_err(LinkFrameworkApple { span });
                                 }
                                 NativeLibKind::Framework { as_needed: None }
                             }
                             "raw-dylib" => {
                                 if !sess.target.is_like_windows {
-                                    struct_span_err!(
-                                        sess,
-                                        span,
-                                        E0455,
-                                        "link kind `raw-dylib` is only supported on Windows targets"
-                                    )
-                                    .emit();
-                                } else if !features.raw_dylib {
+                                    sess.emit_err(FrameworkOnlyWindows { span });
+                                } else if !features.raw_dylib && sess.target.arch == "x86" {
                                     feature_err(
                                         &sess.parse_sess,
                                         sym::raw_dylib,
                                         span,
-                                        "link kind `raw-dylib` is unstable",
+                                        "link kind `raw-dylib` is unstable on x86",
                                     )
                                     .emit();
                                 }
                                 NativeLibKind::RawDylib
                             }
                             kind => {
-                                let msg = format!(
-                                    "unknown link kind `{kind}`, expected one of: \
-                                     static, dylib, framework, raw-dylib"
-                                );
-                                struct_span_err!(sess, span, E0458, "{}", msg)
-                                    .span_label(span, "unknown link kind")
-                                    .emit();
+                                sess.emit_err(UnknownLinkKind { span, kind });
                                 continue;
                             }
                         };
@@ -145,32 +188,26 @@ impl<'tcx> Collector<'tcx> {
                     }
                     sym::modifiers => {
                         if modifiers.is_some() {
-                            let msg =
-                                "multiple `modifiers` arguments in a single `#[link]` attribute";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(MultipleLinkModifiers { span: item.span() });
                             continue;
                         }
                         let Some(link_modifiers) = item.value_str() else {
-                            let msg = "link modifiers must be of the form `modifiers = \"string\"`";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(LinkModifiersForm { span: item.span() });
                             continue;
                         };
                         modifiers = Some((link_modifiers, item.name_value_literal_span().unwrap()));
                     }
                     sym::cfg => {
                         if cfg.is_some() {
-                            let msg = "multiple `cfg` arguments in a single `#[link]` attribute";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(MultipleCfgs { span: item.span() });
                             continue;
                         }
                         let Some(link_cfg) = item.meta_item_list() else {
-                            let msg = "link cfg must be of the form `cfg(/* predicate */)`";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(LinkCfgForm { span: item.span() });
                             continue;
                         };
                         let [NestedMetaItem::MetaItem(link_cfg)] = link_cfg else {
-                            let msg = "link cfg must have a single predicate argument";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(LinkCfgSinglePredicate { span: item.span() });
                             continue;
                         };
                         if !features.link_cfg {
@@ -186,23 +223,55 @@ impl<'tcx> Collector<'tcx> {
                     }
                     sym::wasm_import_module => {
                         if wasm_import_module.is_some() {
-                            let msg = "multiple `wasm_import_module` arguments \
-                                       in a single `#[link]` attribute";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(MultipleWasmImport { span: item.span() });
                             continue;
                         }
                         let Some(link_wasm_import_module) = item.value_str() else {
-                            let msg = "wasm import module must be of the form \
-                                       `wasm_import_module = \"string\"`";
-                            sess.span_err(item.span(), msg);
+                            sess.emit_err(WasmImportForm { span: item.span() });
                             continue;
                         };
                         wasm_import_module = Some((link_wasm_import_module, item.span()));
                     }
+                    sym::import_name_type => {
+                        if import_name_type.is_some() {
+                            sess.emit_err(MultipleImportNameType { span: item.span() });
+                            continue;
+                        }
+                        let Some(link_import_name_type) = item.value_str() else {
+                            sess.emit_err(ImportNameTypeForm { span: item.span() });
+                            continue;
+                        };
+                        if self.tcx.sess.target.arch != "x86" {
+                            sess.emit_err(ImportNameTypeX86 { span: item.span() });
+                            continue;
+                        }
+
+                        let link_import_name_type = match link_import_name_type.as_str() {
+                            "decorated" => PeImportNameType::Decorated,
+                            "noprefix" => PeImportNameType::NoPrefix,
+                            "undecorated" => PeImportNameType::Undecorated,
+                            import_name_type => {
+                                sess.emit_err(UnknownImportNameType {
+                                    span: item.span(),
+                                    import_name_type,
+                                });
+                                continue;
+                            }
+                        };
+                        if !features.raw_dylib {
+                            let span = item.name_value_literal_span().unwrap();
+                            feature_err(
+                                &sess.parse_sess,
+                                sym::raw_dylib,
+                                span,
+                                "import name type is unstable",
+                            )
+                            .emit();
+                        }
+                        import_name_type = Some((link_import_name_type, item.span()));
+                    }
                     _ => {
-                        let msg = "unexpected `#[link]` argument, expected one of: \
-                                   name, kind, modifiers, cfg, wasm_import_module";
-                        sess.span_err(item.span(), msg);
+                        sess.emit_err(UnexpectedLinkArg { span: item.span() });
                     }
                 }
             }
@@ -214,11 +283,7 @@ impl<'tcx> Collector<'tcx> {
                     let (modifier, value) = match modifier.strip_prefix(&['+', '-']) {
                         Some(m) => (m, modifier.starts_with('+')),
                         None => {
-                            sess.span_err(
-                                span,
-                                "invalid linking modifier syntax, expected '+' or '-' prefix \
-                                before one of: bundle, verbatim, whole-archive, as-needed",
-                            );
+                            sess.emit_err(InvalidLinkModifier { span });
                             continue;
                         }
                     };
@@ -236,10 +301,7 @@ impl<'tcx> Collector<'tcx> {
                     }
                     let assign_modifier = |dst: &mut Option<bool>| {
                         if dst.is_some() {
-                            let msg = format!(
-                                "multiple `{modifier}` modifiers in a single `modifiers` argument"
-                            );
-                            sess.span_err(span, &msg);
+                            sess.emit_err(MultipleModifiers { span, modifier });
                         } else {
                             *dst = Some(value);
                         }
@@ -249,11 +311,7 @@ impl<'tcx> Collector<'tcx> {
                             assign_modifier(bundle)
                         }
                         ("bundle", _) => {
-                            sess.span_err(
-                                span,
-                                "linking modifier `bundle` is only compatible with \
-                                 `static` linking kind",
-                            );
+                            sess.emit_err(BundleNeedsStatic { span });
                         }
 
                         ("verbatim", _) => {
@@ -265,11 +323,7 @@ impl<'tcx> Collector<'tcx> {
                             assign_modifier(whole_archive)
                         }
                         ("whole-archive", _) => {
-                            sess.span_err(
-                                span,
-                                "linking modifier `whole-archive` is only compatible with \
-                                 `static` linking kind",
-                            );
+                            sess.emit_err(WholeArchiveNeedsStatic { span });
                         }
 
                         ("as-needed", Some(NativeLibKind::Dylib { as_needed }))
@@ -278,21 +332,11 @@ impl<'tcx> Collector<'tcx> {
                             assign_modifier(as_needed)
                         }
                         ("as-needed", _) => {
-                            sess.span_err(
-                                span,
-                                "linking modifier `as-needed` is only compatible with \
-                                 `dylib` and `framework` linking kinds",
-                            );
+                            sess.emit_err(AsNeededCompatibility { span });
                         }
 
                         _ => {
-                            sess.span_err(
-                                span,
-                                format!(
-                                    "unknown linking modifier `{modifier}`, expected one of: \
-                                     bundle, verbatim, whole-archive, as-needed"
-                                ),
-                            );
+                            sess.emit_err(UnknownLinkModifier { span, modifier });
                         }
                     }
                 }
@@ -300,39 +344,66 @@ impl<'tcx> Collector<'tcx> {
 
             if let Some((_, span)) = wasm_import_module {
                 if name.is_some() || kind.is_some() || modifiers.is_some() || cfg.is_some() {
-                    let msg = "`wasm_import_module` is incompatible with \
-                               other arguments in `#[link]` attributes";
-                    sess.span_err(span, msg);
+                    sess.emit_err(IncompatibleWasmLink { span });
                 }
             } else if name.is_none() {
-                struct_span_err!(
-                    sess,
-                    m.span,
-                    E0459,
-                    "`#[link]` attribute requires a `name = \"string\"` argument"
-                )
-                .span_label(m.span, "missing `name` argument")
-                .emit();
+                sess.emit_err(LinkRequiresName { span: m.span });
+            }
+
+            // Do this outside of the loop so that `import_name_type` can be specified before `kind`.
+            if let Some((_, span)) = import_name_type {
+                if kind != Some(NativeLibKind::RawDylib) {
+                    sess.emit_err(ImportNameTypeRaw { span });
+                }
             }
 
             let dll_imports = match kind {
                 Some(NativeLibKind::RawDylib) => {
                     if let Some((name, span)) = name && name.as_str().contains('\0') {
-                        sess.span_err(
-                            span,
-                            "link name must not contain NUL characters if link kind is `raw-dylib`",
-                        );
+                        sess.emit_err(RawDylibNoNul { span });
                     }
                     foreign_mod_items
                         .iter()
-                        .map(|child_item| self.build_dll_import(abi, child_item))
+                        .map(|child_item| {
+                            self.build_dll_import(
+                                abi,
+                                import_name_type.map(|(import_name_type, _)| import_name_type),
+                                child_item,
+                            )
+                        })
                         .collect()
                 }
-                _ => Vec::new(),
+                _ => {
+                    for child_item in foreign_mod_items {
+                        if self.tcx.def_kind(child_item.id.def_id).has_codegen_attrs()
+                            && self
+                                .tcx
+                                .codegen_fn_attrs(child_item.id.def_id)
+                                .link_ordinal
+                                .is_some()
+                        {
+                            let link_ordinal_attr = self
+                                .tcx
+                                .hir()
+                                .attrs(self.tcx.hir().local_def_id_to_hir_id(child_item.id.def_id))
+                                .iter()
+                                .find(|a| a.has_name(sym::link_ordinal))
+                                .unwrap();
+                            sess.emit_err(LinkOrdinalRawDylib { span: link_ordinal_attr.span });
+                        }
+                    }
+
+                    Vec::new()
+                }
             };
+
+            let name = name.map(|(name, _)| name);
+            let kind = kind.unwrap_or(NativeLibKind::Unspecified);
+            let filename = find_bundled_library(name, verbatim, kind, sess);
             self.libs.push(NativeLib {
-                name: name.map(|(name, _)| name),
-                kind: kind.unwrap_or(NativeLibKind::Unspecified),
+                name,
+                filename,
+                kind,
                 cfg,
                 foreign_module: Some(it.def_id.to_def_id()),
                 wasm_import_module: wasm_import_module.map(|(name, _)| name),
@@ -349,7 +420,7 @@ impl<'tcx> Collector<'tcx> {
         for lib in &self.tcx.sess.opts.libs {
             if let NativeLibKind::Framework { .. } = lib.kind && !self.tcx.sess.target.is_like_osx {
                 // Cannot check this when parsing options because the target is not yet available.
-                self.tcx.sess.err("library kind `framework` is only supported on Apple targets");
+                self.tcx.sess.emit_err(LibFrameworkApple);
             }
             if let Some(ref new_name) = lib.new_name {
                 let any_duplicate = self
@@ -358,23 +429,11 @@ impl<'tcx> Collector<'tcx> {
                     .filter_map(|lib| lib.name.as_ref())
                     .any(|n| n.as_str() == lib.name);
                 if new_name.is_empty() {
-                    self.tcx.sess.err(format!(
-                        "an empty renaming target was specified for library `{}`",
-                        lib.name
-                    ));
+                    self.tcx.sess.emit_err(EmptyRenamingTarget { lib_name: &lib.name });
                 } else if !any_duplicate {
-                    self.tcx.sess.err(format!(
-                        "renaming of the library `{}` was specified, \
-                                                however this crate contains no `#[link(...)]` \
-                                                attributes referencing this library",
-                        lib.name
-                    ));
+                    self.tcx.sess.emit_err(RenamingNoLink { lib_name: &lib.name });
                 } else if !renames.insert(&lib.name) {
-                    self.tcx.sess.err(format!(
-                        "multiple renamings were \
-                                                specified for library `{}`",
-                        lib.name
-                    ));
+                    self.tcx.sess.emit_err(MultipleRenamings { lib_name: &lib.name });
                 }
             }
         }
@@ -399,10 +458,13 @@ impl<'tcx> Collector<'tcx> {
                             // involved or not, library reordering and kind overriding without
                             // explicit `:rename` in particular.
                             if lib.has_modifiers() || passed_lib.has_modifiers() {
-                                let msg = "overriding linking modifiers from command line is not supported";
                                 match lib.foreign_module {
-                                    Some(def_id) => self.tcx.sess.span_err(self.tcx.def_span(def_id), msg),
-                                    None => self.tcx.sess.err(msg),
+                                    Some(def_id) => self.tcx.sess.emit_err(NoLinkModOverride {
+                                        span: Some(self.tcx.def_span(def_id)),
+                                    }),
+                                    None => {
+                                        self.tcx.sess.emit_err(NoLinkModOverride { span: None })
+                                    }
                                 };
                             }
                             if passed_lib.kind != NativeLibKind::Unspecified {
@@ -421,8 +483,13 @@ impl<'tcx> Collector<'tcx> {
             if existing.is_empty() {
                 // Add if not found
                 let new_name: Option<&str> = passed_lib.new_name.as_deref();
+                let name = Some(Symbol::intern(new_name.unwrap_or(&passed_lib.name)));
+                let sess = self.tcx.sess;
+                let filename =
+                    find_bundled_library(name, passed_lib.verbatim, passed_lib.kind, sess);
                 self.libs.push(NativeLib {
-                    name: Some(Symbol::intern(new_name.unwrap_or(&passed_lib.name))),
+                    name,
+                    filename,
                     kind: passed_lib.kind,
                     cfg: None,
                     foreign_module: None,
@@ -462,7 +529,12 @@ impl<'tcx> Collector<'tcx> {
             .sum()
     }
 
-    fn build_dll_import(&self, abi: Abi, item: &hir::ForeignItemRef) -> DllImport {
+    fn build_dll_import(
+        &self,
+        abi: Abi,
+        import_name_type: Option<PeImportNameType>,
+        item: &hir::ForeignItemRef,
+    ) -> DllImport {
         let calling_convention = if self.tcx.sess.target.arch == "x86" {
             match abi {
                 Abi::C { .. } | Abi::Cdecl { .. } => DllCallingConvention::C,
@@ -476,29 +548,29 @@ impl<'tcx> Collector<'tcx> {
                     DllCallingConvention::Vectorcall(self.i686_arg_list_size(item))
                 }
                 _ => {
-                    self.tcx.sess.span_fatal(
-                        item.span,
-                        r#"ABI not supported by `#[link(kind = "raw-dylib")]` on i686"#,
-                    );
+                    self.tcx.sess.emit_fatal(UnsupportedAbiI686 { span: item.span });
                 }
             }
         } else {
             match abi {
                 Abi::C { .. } | Abi::Win64 { .. } | Abi::System { .. } => DllCallingConvention::C,
                 _ => {
-                    self.tcx.sess.span_fatal(
-                        item.span,
-                        r#"ABI not supported by `#[link(kind = "raw-dylib")]` on this architecture"#,
-                    );
+                    self.tcx.sess.emit_fatal(UnsupportedAbi { span: item.span });
                 }
             }
         };
 
+        let codegen_fn_attrs = self.tcx.codegen_fn_attrs(item.id.def_id);
+        let import_name_type = codegen_fn_attrs
+            .link_ordinal
+            .map_or(import_name_type, |ord| Some(PeImportNameType::Ordinal(ord)));
+
         DllImport {
-            name: item.ident.name,
-            ordinal: self.tcx.codegen_fn_attrs(item.id.def_id).link_ordinal,
+            name: codegen_fn_attrs.link_name.unwrap_or(item.ident.name),
+            import_name_type,
             calling_convention,
             span: item.span,
+            is_fn: self.tcx.def_kind(item.id.def_id).is_fn_like(),
         }
     }
 }
diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index 40dc4fb05..830417eea 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -4,7 +4,6 @@ use crate::creader::{CStore, CrateMetadataRef};
 use crate::rmeta::*;
 
 use rustc_ast as ast;
-use rustc_ast::ptr::P;
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::svh::Svh;
@@ -33,7 +32,7 @@ use rustc_session::cstore::{
 use rustc_session::Session;
 use rustc_span::hygiene::{ExpnIndex, MacroKind};
 use rustc_span::source_map::{respan, Spanned};
-use rustc_span::symbol::{sym, Ident, Symbol};
+use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{self, BytePos, ExpnId, Pos, Span, SyntaxContext, DUMMY_SP};
 
 use proc_macro::bridge::client::ProcMacro;
@@ -42,7 +41,6 @@ use std::iter::TrustedLen;
 use std::mem;
 use std::num::NonZeroUsize;
 use std::path::Path;
-use tracing::debug;
 
 pub(super) use cstore_impl::provide;
 pub use cstore_impl::provide_extern;
@@ -99,7 +97,7 @@ pub(crate) struct CrateMetadata {
     /// Proc macro descriptions for this crate, if it's a proc macro crate.
     raw_proc_macros: Option<&'static [ProcMacro]>,
     /// Source maps for code from the crate.
-    source_map_import_info: OnceCell<Vec<ImportedSourceFile>>,
+    source_map_import_info: Lock<Vec<Option<ImportedSourceFile>>>,
     /// For every definition in this crate, maps its `DefPathHash` to its `DefIndex`.
     def_path_hash_map: DefPathHashMapRef<'static>,
     /// Likewise for ExpnHash.
@@ -143,7 +141,8 @@ pub(crate) struct CrateMetadata {
 }
 
 /// Holds information about a rustc_span::SourceFile imported from another crate.
-/// See `imported_source_files()` for more information.
+/// See `imported_source_file()` for more information.
+#[derive(Clone)]
 struct ImportedSourceFile {
     /// This SourceFile's byte-offset within the source_map of its original crate
     original_start_pos: rustc_span::BytePos,
@@ -160,9 +159,6 @@ pub(super) struct DecodeContext<'a, 'tcx> {
     sess: Option<&'tcx Session>,
     tcx: Option<TyCtxt<'tcx>>,
 
-    // Cache the last used source_file for translating spans as an optimization.
-    last_source_file_index: usize,
-
     lazy_state: LazyState,
 
     // Used for decoding interpret::AllocIds in a cached & thread-safe manner.
@@ -191,7 +187,6 @@ pub(super) trait Metadata<'a, 'tcx>: Copy {
             blob: self.blob(),
             sess: self.sess().or(tcx.map(|tcx| tcx.sess)),
             tcx,
-            last_source_file_index: 0,
             lazy_state: LazyState::NoNode,
             alloc_decoding_session: self
                 .cdata()
@@ -455,6 +450,13 @@ impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for ExpnIndex {
     }
 }
 
+impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for ast::AttrId {
+    fn decode(d: &mut DecodeContext<'a, 'tcx>) -> ast::AttrId {
+        let sess = d.sess.expect("can't decode AttrId without Session");
+        sess.parse_sess.attr_id_generator.mk_attr_id()
+    }
+}
+
 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for SyntaxContext {
     fn decode(decoder: &mut DecodeContext<'a, 'tcx>) -> SyntaxContext {
         let cdata = decoder.cdata();
@@ -527,6 +529,9 @@ impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for Span {
             bug!("Cannot decode Span without Session.")
         };
 
+        // Index of the file in the corresponding crate's list of encoded files.
+        let metadata_index = u32::decode(decoder);
+
         // There are two possibilities here:
         // 1. This is a 'local span', which is located inside a `SourceFile`
         // that came from this crate. In this case, we use the source map data
@@ -553,10 +558,10 @@ impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for Span {
         // to be based on the *foreign* crate (e.g. crate C), not the crate
         // we are writing metadata for (e.g. crate B). This allows us to
         // treat the 'local' and 'foreign' cases almost identically during deserialization:
-        // we can call `imported_source_files` for the proper crate, and binary search
+        // we can call `imported_source_file` for the proper crate, and binary search
         // through the returned slice using our span.
-        let imported_source_files = if tag == TAG_VALID_SPAN_LOCAL {
-            decoder.cdata().imported_source_files(sess)
+        let source_file = if tag == TAG_VALID_SPAN_LOCAL {
+            decoder.cdata().imported_source_file(metadata_index, sess)
         } else {
             // When we encode a proc-macro crate, all `Span`s should be encoded
             // with `TAG_VALID_SPAN_LOCAL`
@@ -577,66 +582,69 @@ impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for Span {
                 cnum
             );
 
-            // Decoding 'foreign' spans should be rare enough that it's
-            // not worth it to maintain a per-CrateNum cache for `last_source_file_index`.
-            // We just set it to 0, to ensure that we don't try to access something out
-            // of bounds for our initial 'guess'
-            decoder.last_source_file_index = 0;
-
             let foreign_data = decoder.cdata().cstore.get_crate_data(cnum);
-            foreign_data.imported_source_files(sess)
-        };
-
-        let source_file = {
-            // Optimize for the case that most spans within a translated item
-            // originate from the same source_file.
-            let last_source_file = &imported_source_files[decoder.last_source_file_index];
-
-            if lo >= last_source_file.original_start_pos && lo <= last_source_file.original_end_pos
-            {
-                last_source_file
-            } else {
-                let index = imported_source_files
-                    .binary_search_by_key(&lo, |source_file| source_file.original_start_pos)
-                    .unwrap_or_else(|index| index - 1);
-
-                // Don't try to cache the index for foreign spans,
-                // as this would require a map from CrateNums to indices
-                if tag == TAG_VALID_SPAN_LOCAL {
-                    decoder.last_source_file_index = index;
-                }
-                &imported_source_files[index]
-            }
+            foreign_data.imported_source_file(metadata_index, sess)
         };
 
-        // Make sure our binary search above is correct.
+        // Make sure our span is well-formed.
         debug_assert!(
-            lo >= source_file.original_start_pos && lo <= source_file.original_end_pos,
-            "Bad binary search: lo={:?} source_file.original_start_pos={:?} source_file.original_end_pos={:?}",
+            lo + source_file.original_start_pos <= source_file.original_end_pos,
+            "Malformed encoded span: lo={:?} source_file.original_start_pos={:?} source_file.original_end_pos={:?}",
             lo,
             source_file.original_start_pos,
             source_file.original_end_pos
         );
 
-        // Make sure we correctly filtered out invalid spans during encoding
+        // Make sure we correctly filtered out invalid spans during encoding.
         debug_assert!(
-            hi >= source_file.original_start_pos && hi <= source_file.original_end_pos,
-            "Bad binary search: hi={:?} source_file.original_start_pos={:?} source_file.original_end_pos={:?}",
+            hi + source_file.original_start_pos <= source_file.original_end_pos,
+            "Malformed encoded span: hi={:?} source_file.original_start_pos={:?} source_file.original_end_pos={:?}",
             hi,
             source_file.original_start_pos,
             source_file.original_end_pos
         );
 
-        let lo =
-            (lo + source_file.translated_source_file.start_pos) - source_file.original_start_pos;
-        let hi =
-            (hi + source_file.translated_source_file.start_pos) - source_file.original_start_pos;
+        let lo = lo + source_file.translated_source_file.start_pos;
+        let hi = hi + source_file.translated_source_file.start_pos;
 
         // Do not try to decode parent for foreign spans.
         Span::new(lo, hi, ctxt, None)
     }
 }
 
+impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for Symbol {
+    fn decode(d: &mut DecodeContext<'a, 'tcx>) -> Self {
+        let tag = d.read_u8();
+
+        match tag {
+            SYMBOL_STR => {
+                let s = d.read_str();
+                Symbol::intern(s)
+            }
+            SYMBOL_OFFSET => {
+                // read str offset
+                let pos = d.read_usize();
+                let old_pos = d.opaque.position();
+
+                // move to str ofset and read
+                d.opaque.set_position(pos);
+                let s = d.read_str();
+                let sym = Symbol::intern(s);
+
+                // restore position
+                d.opaque.set_position(old_pos);
+
+                sym
+            }
+            SYMBOL_PREINTERNED => {
+                let symbol_index = d.read_u32();
+                Symbol::new_from_decoded(symbol_index)
+            }
+            _ => unreachable!(),
+        }
+    }
+}
+
 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for &'tcx [ty::abstract_const::Node<'tcx>] {
     fn decode(d: &mut DecodeContext<'a, 'tcx>) -> Self {
         ty::codec::RefDecodable::decode(d)
@@ -783,26 +791,11 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         self.opt_item_ident(item_index, sess).expect("no encoded ident for item")
     }
 
-    fn maybe_kind(self, item_id: DefIndex) -> Option<EntryKind> {
-        self.root.tables.kind.get(self, item_id).map(|k| k.decode(self))
-    }
-
     #[inline]
     pub(super) fn map_encoded_cnum_to_current(self, cnum: CrateNum) -> CrateNum {
         if cnum == LOCAL_CRATE { self.cnum } else { self.cnum_map[cnum] }
     }
 
-    fn kind(self, item_id: DefIndex) -> EntryKind {
-        self.maybe_kind(item_id).unwrap_or_else(|| {
-            bug!(
-                "CrateMetadata::kind({:?}): id not found, in crate {:?} with number {}",
-                item_id,
-                self.root.name,
-                self.cnum,
-            )
-        })
-    }
-
     fn def_kind(self, item_id: DefIndex) -> DefKind {
         self.root.tables.opt_def_kind.get(self, item_id).unwrap_or_else(|| {
             bug!(
@@ -854,21 +847,16 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         )
     }
 
-    fn get_variant(self, kind: &EntryKind, index: DefIndex, parent_did: DefId) -> ty::VariantDef {
-        let data = match kind {
-            EntryKind::Variant(data) | EntryKind::Struct(data) | EntryKind::Union(data) => {
-                data.decode(self)
-            }
-            _ => bug!(),
-        };
-
+    fn get_variant(self, kind: &DefKind, index: DefIndex, parent_did: DefId) -> ty::VariantDef {
         let adt_kind = match kind {
-            EntryKind::Variant(_) => ty::AdtKind::Enum,
-            EntryKind::Struct(..) => ty::AdtKind::Struct,
-            EntryKind::Union(..) => ty::AdtKind::Union,
+            DefKind::Variant => ty::AdtKind::Enum,
+            DefKind::Struct => ty::AdtKind::Struct,
+            DefKind::Union => ty::AdtKind::Union,
             _ => bug!(),
         };
 
+        let data = self.root.tables.variant_data.get(self, index).unwrap().decode(self);
+
         let variant_did =
             if adt_kind == ty::AdtKind::Enum { Some(self.local_def_id(index)) } else { None };
         let ctor_did = data.ctor.map(|index| self.local_def_id(index));
@@ -899,13 +887,13 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     }
 
     fn get_adt_def(self, item_id: DefIndex, tcx: TyCtxt<'tcx>) -> ty::AdtDef<'tcx> {
-        let kind = self.kind(item_id);
+        let kind = self.def_kind(item_id);
         let did = self.local_def_id(item_id);
 
         let adt_kind = match kind {
-            EntryKind::Enum => ty::AdtKind::Enum,
-            EntryKind::Struct(_) => ty::AdtKind::Struct,
-            EntryKind::Union(_) => ty::AdtKind::Union,
+            DefKind::Enum => ty::AdtKind::Enum,
+            DefKind::Struct => ty::AdtKind::Struct,
+            DefKind::Union => ty::AdtKind::Union,
             _ => bug!("get_adt_def called on a non-ADT {:?}", did),
         };
         let repr = self.root.tables.repr_options.get(self, item_id).unwrap().decode(self);
@@ -917,7 +905,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
                 .get(self, item_id)
                 .unwrap_or_else(LazyArray::empty)
                 .decode(self)
-                .map(|index| self.get_variant(&self.kind(index), index, did))
+                .map(|index| self.get_variant(&self.def_kind(index), index, did))
                 .collect()
         } else {
             std::iter::once(self.get_variant(&kind, item_id, did)).collect()
@@ -930,8 +918,14 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         self.root.tables.generics_of.get(self, item_id).unwrap().decode((self, sess))
     }
 
-    fn get_visibility(self, id: DefIndex) -> ty::Visibility {
-        self.root.tables.visibility.get(self, id).unwrap().decode(self)
+    fn get_visibility(self, id: DefIndex) -> ty::Visibility<DefId> {
+        self.root
+            .tables
+            .visibility
+            .get(self, id)
+            .unwrap()
+            .decode(self)
+            .map_id(|index| self.local_def_id(index))
     }
 
     fn get_trait_item_def_id(self, id: DefIndex) -> Option<DefId> {
@@ -1027,10 +1021,9 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
                 let vis = self.get_visibility(child_index);
                 let span = self.get_span(child_index, sess);
                 let macro_rules = match kind {
-                    DefKind::Macro(..) => match self.kind(child_index) {
-                        EntryKind::MacroDef(_, macro_rules) => macro_rules,
-                        _ => unreachable!(),
-                    },
+                    DefKind::Macro(..) => {
+                        self.root.tables.macro_rules.get(self, child_index).is_some()
+                    }
                     _ => false,
                 };
 
@@ -1084,14 +1077,10 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             }
         }
 
-        match self.kind(id) {
-            EntryKind::Mod(exports) => {
-                for exp in exports.decode((self, sess)) {
-                    callback(exp);
-                }
+        if let Some(exports) = self.root.tables.module_reexports.get(self, id) {
+            for exp in exports.decode((self, sess)) {
+                callback(exp);
             }
-            EntryKind::Enum | EntryKind::Trait => {}
-            _ => bug!("`for_each_module_child` is called on a non-module: {:?}", self.def_kind(id)),
         }
     }
 
@@ -1104,19 +1093,21 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     }
 
     fn module_expansion(self, id: DefIndex, sess: &Session) -> ExpnId {
-        match self.kind(id) {
-            EntryKind::Mod(_) | EntryKind::Enum | EntryKind::Trait => {
-                self.get_expn_that_defined(id, sess)
-            }
+        match self.def_kind(id) {
+            DefKind::Mod | DefKind::Enum | DefKind::Trait => self.get_expn_that_defined(id, sess),
             _ => panic!("Expected module, found {:?}", self.local_def_id(id)),
         }
     }
 
-    fn get_fn_has_self_parameter(self, id: DefIndex) -> bool {
-        match self.kind(id) {
-            EntryKind::AssocFn { has_self, .. } => has_self,
-            _ => false,
-        }
+    fn get_fn_has_self_parameter(self, id: DefIndex, sess: &'a Session) -> bool {
+        self.root
+            .tables
+            .fn_arg_names
+            .get(self, id)
+            .unwrap_or_else(LazyArray::empty)
+            .decode((self, sess))
+            .nth(0)
+            .map_or(false, |ident| ident.name == kw::SelfLower)
     }
 
     fn get_associated_item_def_ids(
@@ -1133,15 +1124,17 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             .map(move |child_index| self.local_def_id(child_index))
     }
 
-    fn get_associated_item(self, id: DefIndex) -> ty::AssocItem {
+    fn get_associated_item(self, id: DefIndex, sess: &'a Session) -> ty::AssocItem {
         let name = self.item_name(id);
 
-        let (kind, container, has_self) = match self.kind(id) {
-            EntryKind::AssocConst(container) => (ty::AssocKind::Const, container, false),
-            EntryKind::AssocFn { container, has_self } => (ty::AssocKind::Fn, container, has_self),
-            EntryKind::AssocType(container) => (ty::AssocKind::Type, container, false),
-            _ => bug!("cannot get associated-item of `{:?}`", id),
+        let kind = match self.def_kind(id) {
+            DefKind::AssocConst => ty::AssocKind::Const,
+            DefKind::AssocFn => ty::AssocKind::Fn,
+            DefKind::AssocTy => ty::AssocKind::Type,
+            _ => bug!("cannot get associated-item of `{:?}`", self.def_key(id)),
         };
+        let has_self = self.get_fn_has_self_parameter(id, sess);
+        let container = self.root.tables.assoc_container.get(self, id).unwrap();
 
         ty::AssocItem {
             name,
@@ -1154,9 +1147,9 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     }
 
     fn get_ctor_def_id_and_kind(self, node_id: DefIndex) -> Option<(DefId, CtorKind)> {
-        match self.kind(node_id) {
-            EntryKind::Struct(data) | EntryKind::Variant(data) => {
-                let vdata = data.decode(self);
+        match self.def_kind(node_id) {
+            DefKind::Struct | DefKind::Variant => {
+                let vdata = self.root.tables.variant_data.get(self, node_id).unwrap().decode(self);
                 vdata.ctor.map(|index| (self.local_def_id(index), vdata.ctor_kind))
             }
             _ => None,
@@ -1202,7 +1195,10 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             .map(move |index| respan(self.get_span(index, sess), self.item_name(index)))
     }
 
-    fn get_struct_field_visibilities(self, id: DefIndex) -> impl Iterator<Item = Visibility> + 'a {
+    fn get_struct_field_visibilities(
+        self,
+        id: DefIndex,
+    ) -> impl Iterator<Item = Visibility<DefId>> + 'a {
         self.root
             .tables
             .children
@@ -1344,18 +1340,22 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     }
 
     fn get_macro(self, id: DefIndex, sess: &Session) -> ast::MacroDef {
-        match self.kind(id) {
-            EntryKind::MacroDef(mac_args, macro_rules) => {
-                ast::MacroDef { body: P(mac_args.decode((self, sess))), macro_rules }
+        match self.def_kind(id) {
+            DefKind::Macro(_) => {
+                let macro_rules = self.root.tables.macro_rules.get(self, id).is_some();
+                let body =
+                    self.root.tables.macro_definition.get(self, id).unwrap().decode((self, sess));
+                ast::MacroDef { macro_rules, body: ast::ptr::P(body) }
             }
             _ => bug!(),
         }
     }
 
     fn is_foreign_item(self, id: DefIndex) -> bool {
-        match self.kind(id) {
-            EntryKind::ForeignStatic | EntryKind::ForeignFn => true,
-            _ => false,
+        if let Some(parent) = self.def_key(id).parent {
+            matches!(self.def_kind(parent), DefKind::ForeignMod)
+        } else {
+            false
         }
     }
 
@@ -1453,7 +1453,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     ///
     /// Proc macro crates don't currently export spans, so this function does not have
     /// to work for them.
-    fn imported_source_files(self, sess: &Session) -> &'a [ImportedSourceFile] {
+    fn imported_source_file(self, source_file_index: u32, sess: &Session) -> ImportedSourceFile {
         fn filter<'a>(sess: &Session, path: Option<&'a Path>) -> Option<&'a Path> {
             path.filter(|_| {
                 // Only spend time on further checks if we have what to translate *to*.
@@ -1541,90 +1541,96 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             }
         };
 
-        self.cdata.source_map_import_info.get_or_init(|| {
-            let external_source_map = self.root.source_map.decode(self);
-
-            external_source_map
-                .map(|source_file_to_import| {
-                    // We can't reuse an existing SourceFile, so allocate a new one
-                    // containing the information we need.
-                    let rustc_span::SourceFile {
-                        mut name,
-                        src_hash,
-                        start_pos,
-                        end_pos,
-                        lines,
-                        multibyte_chars,
-                        non_narrow_chars,
-                        normalized_pos,
-                        name_hash,
-                        ..
-                    } = source_file_to_import;
-
-                    // If this file is under $sysroot/lib/rustlib/src/ but has not been remapped
-                    // during rust bootstrapping by `remap-debuginfo = true`, and the user
-                    // wish to simulate that behaviour by -Z simulate-remapped-rust-src-base,
-                    // then we change `name` to a similar state as if the rust was bootstrapped
-                    // with `remap-debuginfo = true`.
-                    // This is useful for testing so that tests about the effects of
-                    // `try_to_translate_virtual_to_real` don't have to worry about how the
-                    // compiler is bootstrapped.
-                    if let Some(virtual_dir) =
-                        &sess.opts.unstable_opts.simulate_remapped_rust_src_base
-                    {
-                        if let Some(real_dir) = &sess.opts.real_rust_source_base_dir {
-                            if let rustc_span::FileName::Real(ref mut old_name) = name {
-                                if let rustc_span::RealFileName::LocalPath(local) = old_name {
-                                    if let Ok(rest) = local.strip_prefix(real_dir) {
-                                        *old_name = rustc_span::RealFileName::Remapped {
-                                            local_path: None,
-                                            virtual_name: virtual_dir.join(rest),
-                                        };
-                                    }
+        let mut import_info = self.cdata.source_map_import_info.lock();
+        for _ in import_info.len()..=(source_file_index as usize) {
+            import_info.push(None);
+        }
+        import_info[source_file_index as usize]
+            .get_or_insert_with(|| {
+                let source_file_to_import = self
+                    .root
+                    .source_map
+                    .get(self, source_file_index)
+                    .expect("missing source file")
+                    .decode(self);
+
+                // We can't reuse an existing SourceFile, so allocate a new one
+                // containing the information we need.
+                let rustc_span::SourceFile {
+                    mut name,
+                    src_hash,
+                    start_pos,
+                    end_pos,
+                    lines,
+                    multibyte_chars,
+                    non_narrow_chars,
+                    normalized_pos,
+                    name_hash,
+                    ..
+                } = source_file_to_import;
+
+                // If this file is under $sysroot/lib/rustlib/src/ but has not been remapped
+                // during rust bootstrapping by `remap-debuginfo = true`, and the user
+                // wish to simulate that behaviour by -Z simulate-remapped-rust-src-base,
+                // then we change `name` to a similar state as if the rust was bootstrapped
+                // with `remap-debuginfo = true`.
+                // This is useful for testing so that tests about the effects of
+                // `try_to_translate_virtual_to_real` don't have to worry about how the
+                // compiler is bootstrapped.
+                if let Some(virtual_dir) = &sess.opts.unstable_opts.simulate_remapped_rust_src_base
+                {
+                    if let Some(real_dir) = &sess.opts.real_rust_source_base_dir {
+                        if let rustc_span::FileName::Real(ref mut old_name) = name {
+                            if let rustc_span::RealFileName::LocalPath(local) = old_name {
+                                if let Ok(rest) = local.strip_prefix(real_dir) {
+                                    *old_name = rustc_span::RealFileName::Remapped {
+                                        local_path: None,
+                                        virtual_name: virtual_dir.join(rest),
+                                    };
                                 }
                             }
                         }
                     }
+                }
 
-                    // If this file's path has been remapped to `/rustc/$hash`,
-                    // we might be able to reverse that (also see comments above,
-                    // on `try_to_translate_virtual_to_real`).
-                    try_to_translate_virtual_to_real(&mut name);
-
-                    let source_length = (end_pos - start_pos).to_usize();
-
-                    let local_version = sess.source_map().new_imported_source_file(
-                        name,
-                        src_hash,
-                        name_hash,
-                        source_length,
-                        self.cnum,
-                        lines,
-                        multibyte_chars,
-                        non_narrow_chars,
-                        normalized_pos,
-                        start_pos,
-                        end_pos,
-                    );
-                    debug!(
-                        "CrateMetaData::imported_source_files alloc \
+                // If this file's path has been remapped to `/rustc/$hash`,
+                // we might be able to reverse that (also see comments above,
+                // on `try_to_translate_virtual_to_real`).
+                try_to_translate_virtual_to_real(&mut name);
+
+                let source_length = (end_pos - start_pos).to_usize();
+
+                let local_version = sess.source_map().new_imported_source_file(
+                    name,
+                    src_hash,
+                    name_hash,
+                    source_length,
+                    self.cnum,
+                    lines,
+                    multibyte_chars,
+                    non_narrow_chars,
+                    normalized_pos,
+                    start_pos,
+                    source_file_index,
+                );
+                debug!(
+                    "CrateMetaData::imported_source_files alloc \
                          source_file {:?} original (start_pos {:?} end_pos {:?}) \
                          translated (start_pos {:?} end_pos {:?})",
-                        local_version.name,
-                        start_pos,
-                        end_pos,
-                        local_version.start_pos,
-                        local_version.end_pos
-                    );
+                    local_version.name,
+                    start_pos,
+                    end_pos,
+                    local_version.start_pos,
+                    local_version.end_pos
+                );
 
-                    ImportedSourceFile {
-                        original_start_pos: start_pos,
-                        original_end_pos: end_pos,
-                        translated_source_file: local_version,
-                    }
-                })
-                .collect()
-        })
+                ImportedSourceFile {
+                    original_start_pos: start_pos,
+                    original_end_pos: end_pos,
+                    translated_source_file: local_version,
+                }
+            })
+            .clone()
     }
 
     fn get_generator_diagnostic_data(
@@ -1687,7 +1693,7 @@ impl CrateMetadata {
             trait_impls,
             incoherent_impls: Default::default(),
             raw_proc_macros,
-            source_map_import_info: OnceCell::new(),
+            source_map_import_info: Lock::new(Vec::new()),
             def_path_hash_map,
             expn_hash_map: Default::default(),
             alloc_decoding_state,
diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
index 38ce50e83..dede1b212 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -76,9 +76,9 @@ impl ProcessQueryValue<'_, Option<DeprecationEntry>> for Option<Deprecation> {
 }
 
 macro_rules! provide_one {
-    (<$lt:tt> $tcx:ident, $def_id:ident, $other:ident, $cdata:ident, $name:ident => { table }) => {
+    ($tcx:ident, $def_id:ident, $other:ident, $cdata:ident, $name:ident => { table }) => {
         provide_one! {
-            <$lt> $tcx, $def_id, $other, $cdata, $name => {
+            $tcx, $def_id, $other, $cdata, $name => {
                 $cdata
                     .root
                     .tables
@@ -89,9 +89,9 @@ macro_rules! provide_one {
             }
         }
     };
-    (<$lt:tt> $tcx:ident, $def_id:ident, $other:ident, $cdata:ident, $name:ident => { table_direct }) => {
+    ($tcx:ident, $def_id:ident, $other:ident, $cdata:ident, $name:ident => { table_direct }) => {
         provide_one! {
-            <$lt> $tcx, $def_id, $other, $cdata, $name => {
+            $tcx, $def_id, $other, $cdata, $name => {
                 // We don't decode `table_direct`, since it's not a Lazy, but an actual value
                 $cdata
                     .root
@@ -102,11 +102,11 @@ macro_rules! provide_one {
             }
         }
     };
-    (<$lt:tt> $tcx:ident, $def_id:ident, $other:ident, $cdata:ident, $name:ident => $compute:block) => {
-        fn $name<$lt>(
-            $tcx: TyCtxt<$lt>,
-            def_id_arg: ty::query::query_keys::$name<$lt>,
-        ) -> ty::query::query_values::$name<$lt> {
+    ($tcx:ident, $def_id:ident, $other:ident, $cdata:ident, $name:ident => $compute:block) => {
+        fn $name<'tcx>(
+            $tcx: TyCtxt<'tcx>,
+            def_id_arg: ty::query::query_keys::$name<'tcx>,
+        ) -> ty::query::query_values::$name<'tcx> {
             let _prof_timer =
                 $tcx.prof.generic_activity(concat!("metadata_decode_entry_", stringify!($name)));
 
@@ -130,11 +130,11 @@ macro_rules! provide_one {
 }
 
 macro_rules! provide {
-    (<$lt:tt> $tcx:ident, $def_id:ident, $other:ident, $cdata:ident,
+    ($tcx:ident, $def_id:ident, $other:ident, $cdata:ident,
       $($name:ident => { $($compute:tt)* })*) => {
         pub fn provide_extern(providers: &mut ExternProviders) {
             $(provide_one! {
-                <$lt> $tcx, $def_id, $other, $cdata, $name => { $($compute)* }
+                $tcx, $def_id, $other, $cdata, $name => { $($compute)* }
             })*
 
             *providers = ExternProviders {
@@ -187,7 +187,7 @@ impl IntoArgs for (CrateNum, SimplifiedType) {
     }
 }
 
-provide! { <'tcx> tcx, def_id, other, cdata,
+provide! { tcx, def_id, other, cdata,
     explicit_item_bounds => { table }
     explicit_predicates_of => { table }
     generics_of => { table }
@@ -199,6 +199,7 @@ provide! { <'tcx> tcx, def_id, other, cdata,
     codegen_fn_attrs => { table }
     impl_trait_ref => { table }
     const_param_default => { table }
+    object_lifetime_default => { table }
     thir_abstract_const => { table }
     optimized_mir => { table }
     mir_for_ctfe => { table }
@@ -207,8 +208,8 @@ provide! { <'tcx> tcx, def_id, other, cdata,
     def_ident_span => { table }
     lookup_stability => { table }
     lookup_const_stability => { table }
+    lookup_default_body_stability => { table }
     lookup_deprecation_entry => { table }
-    visibility => { table }
     unused_generic_params => { table }
     opt_def_kind => { table_direct }
     impl_parent => { table }
@@ -223,6 +224,7 @@ provide! { <'tcx> tcx, def_id, other, cdata,
     generator_kind => { table }
     trait_def => { table }
 
+    visibility => { cdata.get_visibility(def_id.index) }
     adt_def => { cdata.get_adt_def(def_id.index, tcx) }
     adt_destructor => {
         let _ = cdata;
@@ -231,7 +233,7 @@ provide! { <'tcx> tcx, def_id, other, cdata,
     associated_item_def_ids => {
         tcx.arena.alloc_from_iter(cdata.get_associated_item_def_ids(def_id.index, tcx.sess))
     }
-    associated_item => { cdata.get_associated_item(def_id.index) }
+    associated_item => { cdata.get_associated_item(def_id.index, tcx.sess) }
     inherent_impls => { cdata.get_inherent_implementations_for_type(tcx, def_id.index) }
     is_foreign_item => { cdata.is_foreign_item(def_id.index) }
     item_attrs => { tcx.arena.alloc_from_iter(cdata.get_item_attrs(def_id.index, tcx.sess)) }
@@ -340,7 +342,8 @@ pub(in crate::rmeta) fn provide(providers: &mut Providers) {
             assert_eq!(cnum, LOCAL_CRATE);
             false
         },
-        native_library_kind: |tcx, id| {
+        native_library_kind: |tcx, id| tcx.native_library(id).map(|l| l.kind),
+        native_library: |tcx, id| {
             tcx.native_libraries(id.krate)
                 .iter()
                 .filter(|lib| native_libs::relevant_lib(&tcx.sess, lib))
@@ -354,7 +357,6 @@ pub(in crate::rmeta) fn provide(providers: &mut Providers) {
                         .foreign_items
                         .contains(&id)
                 })
-                .map(|l| l.kind)
         },
         native_libraries: |tcx, cnum| {
             assert_eq!(cnum, LOCAL_CRATE);
@@ -483,7 +485,7 @@ impl CStore {
     pub fn struct_field_visibilities_untracked(
         &self,
         def: DefId,
-    ) -> impl Iterator<Item = Visibility> + '_ {
+    ) -> impl Iterator<Item = Visibility<DefId>> + '_ {
         self.get_crate_data(def.krate).get_struct_field_visibilities(def.index)
     }
 
@@ -491,7 +493,7 @@ impl CStore {
         self.get_crate_data(def.krate).get_ctor_def_id_and_kind(def.index)
     }
 
-    pub fn visibility_untracked(&self, def: DefId) -> Visibility {
+    pub fn visibility_untracked(&self, def: DefId) -> Visibility<DefId> {
         self.get_crate_data(def.krate).get_visibility(def.index)
     }
 
@@ -533,8 +535,8 @@ impl CStore {
         )
     }
 
-    pub fn fn_has_self_parameter_untracked(&self, def: DefId) -> bool {
-        self.get_crate_data(def.krate).get_fn_has_self_parameter(def.index)
+    pub fn fn_has_self_parameter_untracked(&self, def: DefId, sess: &Session) -> bool {
+        self.get_crate_data(def.krate).get_fn_has_self_parameter(def.index, sess)
     }
 
     pub fn crate_source_untracked(&self, cnum: CrateNum) -> Lrc<CrateSource> {
@@ -675,6 +677,9 @@ impl CrateStore for CStore {
     }
 
     fn import_source_files(&self, sess: &Session, cnum: CrateNum) {
-        self.get_crate_data(cnum).imported_source_files(sess);
+        let cdata = self.get_crate_data(cnum);
+        for file_index in 0..cdata.root.source_map.size() {
+            cdata.imported_source_file(file_index as u32, sess);
+        }
     }
 }
diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index 33278367c..5a60ea794 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -1,3 +1,4 @@
+use crate::errors::{FailCreateFileEncoder, FailSeekFile, FailWriteFile};
 use crate::rmeta::def_path_hash_map::DefPathHashMapRef;
 use crate::rmeta::table::TableBuilder;
 use crate::rmeta::*;
@@ -16,8 +17,6 @@ use rustc_hir::def_id::{
 use rustc_hir::definitions::DefPathData;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::lang_items;
-use rustc_hir::{AnonConst, GenericParamKind};
-use rustc_index::bit_set::GrowableBitSet;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::dependency_format::Linkage;
 use rustc_middle::middle::exported_symbols::{
@@ -39,12 +38,12 @@ use rustc_span::{
 };
 use rustc_target::abi::VariantIdx;
 use std::borrow::Borrow;
+use std::collections::hash_map::Entry;
 use std::hash::Hash;
 use std::io::{Read, Seek, Write};
 use std::iter;
 use std::num::NonZeroUsize;
 use std::path::{Path, PathBuf};
-use tracing::{debug, trace};
 
 pub(super) struct EncodeContext<'a, 'tcx> {
     opaque: opaque::FileEncoder,
@@ -66,15 +65,13 @@ pub(super) struct EncodeContext<'a, 'tcx> {
     // The indices (into the `SourceMap`'s `MonotonicVec`)
     // of all of the `SourceFiles` that we need to serialize.
     // When we serialize a `Span`, we insert the index of its
-    // `SourceFile` into the `GrowableBitSet`.
-    //
-    // This needs to be a `GrowableBitSet` and not a
-    // regular `BitSet` because we may actually import new `SourceFiles`
-    // during metadata encoding, due to executing a query
-    // with a result containing a foreign `Span`.
-    required_source_files: Option<GrowableBitSet<usize>>,
+    // `SourceFile` into the `FxIndexSet`.
+    // The order inside the `FxIndexSet` is used as on-disk
+    // order of `SourceFiles`, and encoded inside `Span`s.
+    required_source_files: Option<FxIndexSet<usize>>,
     is_proc_macro: bool,
     hygiene_ctxt: &'a HygieneEncodeContext,
+    symbol_table: FxHashMap<Symbol, usize>,
 }
 
 /// If the current crate is a proc-macro, returns early with `Lazy:empty()`.
@@ -238,17 +235,15 @@ impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for Span {
             s.source_file_cache =
                 (source_map.files()[source_file_index].clone(), source_file_index);
         }
+        let (ref source_file, source_file_index) = s.source_file_cache;
+        debug_assert!(source_file.contains(span.lo));
 
-        if !s.source_file_cache.0.contains(span.hi) {
+        if !source_file.contains(span.hi) {
             // Unfortunately, macro expansion still sometimes generates Spans
             // that malformed in this way.
             return TAG_PARTIAL_SPAN.encode(s);
         }
 
-        let source_files = s.required_source_files.as_mut().expect("Already encoded SourceMap!");
-        // Record the fact that we need to encode the data for this `SourceFile`
-        source_files.insert(s.source_file_cache.1);
-
         // There are two possible cases here:
         // 1. This span comes from a 'foreign' crate - e.g. some crate upstream of the
         // crate we are writing metadata for. When the metadata for *this* crate gets
@@ -265,7 +260,7 @@ impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for Span {
         // if we're a proc-macro crate.
         // This allows us to avoid loading the dependencies of proc-macro crates: all of
         // the information we need to decode `Span`s is stored in the proc-macro crate.
-        let (tag, lo, hi) = if s.source_file_cache.0.is_imported() && !s.is_proc_macro {
+        let (tag, metadata_index) = if source_file.is_imported() && !s.is_proc_macro {
             // To simplify deserialization, we 'rebase' this span onto the crate it originally came from
             // (the crate that 'owns' the file it references. These rebased 'lo' and 'hi' values
             // are relative to the source map information for the 'foreign' crate whose CrateNum
@@ -275,29 +270,41 @@ impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for Span {
             //
             // All of this logic ensures that the final result of deserialization is a 'normal'
             // Span that can be used without any additional trouble.
-            let external_start_pos = {
+            let metadata_index = {
                 // Introduce a new scope so that we drop the 'lock()' temporary
-                match &*s.source_file_cache.0.external_src.lock() {
-                    ExternalSource::Foreign { original_start_pos, .. } => *original_start_pos,
+                match &*source_file.external_src.lock() {
+                    ExternalSource::Foreign { metadata_index, .. } => *metadata_index,
                     src => panic!("Unexpected external source {:?}", src),
                 }
             };
-            let lo = (span.lo - s.source_file_cache.0.start_pos) + external_start_pos;
-            let hi = (span.hi - s.source_file_cache.0.start_pos) + external_start_pos;
 
-            (TAG_VALID_SPAN_FOREIGN, lo, hi)
+            (TAG_VALID_SPAN_FOREIGN, metadata_index)
         } else {
-            (TAG_VALID_SPAN_LOCAL, span.lo, span.hi)
+            // Record the fact that we need to encode the data for this `SourceFile`
+            let source_files =
+                s.required_source_files.as_mut().expect("Already encoded SourceMap!");
+            let (metadata_index, _) = source_files.insert_full(source_file_index);
+            let metadata_index: u32 =
+                metadata_index.try_into().expect("cannot export more than U32_MAX files");
+
+            (TAG_VALID_SPAN_LOCAL, metadata_index)
         };
 
-        tag.encode(s);
-        lo.encode(s);
+        // Encode the start position relative to the file start, so we profit more from the
+        // variable-length integer encoding.
+        let lo = span.lo - source_file.start_pos;
 
         // Encode length which is usually less than span.hi and profits more
         // from the variable-length integer encoding that we use.
-        let len = hi - lo;
+        let len = span.hi - span.lo;
+
+        tag.encode(s);
+        lo.encode(s);
         len.encode(s);
 
+        // Encode the index of the `SourceFile` for the span, in order to make decoding faster.
+        metadata_index.encode(s);
+
         if tag == TAG_VALID_SPAN_FOREIGN {
             // This needs to be two lines to avoid holding the `s.source_file_cache`
             // while calling `cnum.encode(s)`
@@ -307,6 +314,31 @@ impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for Span {
     }
 }
 
+impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for Symbol {
+    fn encode(&self, s: &mut EncodeContext<'a, 'tcx>) {
+        // if symbol preinterned, emit tag and symbol index
+        if self.is_preinterned() {
+            s.opaque.emit_u8(SYMBOL_PREINTERNED);
+            s.opaque.emit_u32(self.as_u32());
+        } else {
+            // otherwise write it as string or as offset to it
+            match s.symbol_table.entry(*self) {
+                Entry::Vacant(o) => {
+                    s.opaque.emit_u8(SYMBOL_STR);
+                    let pos = s.opaque.position();
+                    o.insert(pos);
+                    s.emit_str(self.as_str());
+                }
+                Entry::Occupied(o) => {
+                    let x = o.get().clone();
+                    s.emit_u8(SYMBOL_OFFSET);
+                    s.emit_usize(x);
+                }
+            }
+        }
+    }
+}
+
 impl<'a, 'tcx> TyEncoder for EncodeContext<'a, 'tcx> {
     const CLEAR_CROSS_CRATE: bool = true;
 
@@ -449,7 +481,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         self.lazy(DefPathHashMapRef::BorrowedFromTcx(self.tcx.def_path_hash_to_def_index_map()))
     }
 
-    fn encode_source_map(&mut self) -> LazyArray<rustc_span::SourceFile> {
+    fn encode_source_map(&mut self) -> LazyTable<u32, LazyValue<rustc_span::SourceFile>> {
         let source_map = self.tcx.sess.source_map();
         let all_source_files = source_map.files();
 
@@ -460,66 +492,64 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
 
         let working_directory = &self.tcx.sess.opts.working_dir;
 
-        let adapted = all_source_files
-            .iter()
-            .enumerate()
-            .filter(|(idx, source_file)| {
-                // Only serialize `SourceFile`s that were used
-                // during the encoding of a `Span`
-                required_source_files.contains(*idx) &&
-                // Don't serialize imported `SourceFile`s, unless
-                // we're in a proc-macro crate.
-                (!source_file.is_imported() || self.is_proc_macro)
-            })
-            .map(|(_, source_file)| {
-                // At export time we expand all source file paths to absolute paths because
-                // downstream compilation sessions can have a different compiler working
-                // directory, so relative paths from this or any other upstream crate
-                // won't be valid anymore.
-                //
-                // At this point we also erase the actual on-disk path and only keep
-                // the remapped version -- as is necessary for reproducible builds.
-                match source_file.name {
-                    FileName::Real(ref original_file_name) => {
-                        let adapted_file_name =
-                            source_map.path_mapping().to_embeddable_absolute_path(
-                                original_file_name.clone(),
-                                working_directory,
-                            );
-
-                        if adapted_file_name != *original_file_name {
-                            let mut adapted: SourceFile = (**source_file).clone();
-                            adapted.name = FileName::Real(adapted_file_name);
-                            adapted.name_hash = {
-                                let mut hasher: StableHasher = StableHasher::new();
-                                adapted.name.hash(&mut hasher);
-                                hasher.finish::<u128>()
-                            };
-                            Lrc::new(adapted)
-                        } else {
-                            // Nothing to adapt
-                            source_file.clone()
-                        }
+        let mut adapted = TableBuilder::default();
+
+        // Only serialize `SourceFile`s that were used during the encoding of a `Span`.
+        //
+        // The order in which we encode source files is important here: the on-disk format for
+        // `Span` contains the index of the corresponding `SourceFile`.
+        for (on_disk_index, &source_file_index) in required_source_files.iter().enumerate() {
+            let source_file = &all_source_files[source_file_index];
+            // Don't serialize imported `SourceFile`s, unless we're in a proc-macro crate.
+            assert!(!source_file.is_imported() || self.is_proc_macro);
+
+            // At export time we expand all source file paths to absolute paths because
+            // downstream compilation sessions can have a different compiler working
+            // directory, so relative paths from this or any other upstream crate
+            // won't be valid anymore.
+            //
+            // At this point we also erase the actual on-disk path and only keep
+            // the remapped version -- as is necessary for reproducible builds.
+            let mut source_file = match source_file.name {
+                FileName::Real(ref original_file_name) => {
+                    let adapted_file_name = source_map
+                        .path_mapping()
+                        .to_embeddable_absolute_path(original_file_name.clone(), working_directory);
+
+                    if adapted_file_name != *original_file_name {
+                        let mut adapted: SourceFile = (**source_file).clone();
+                        adapted.name = FileName::Real(adapted_file_name);
+                        adapted.name_hash = {
+                            let mut hasher: StableHasher = StableHasher::new();
+                            adapted.name.hash(&mut hasher);
+                            hasher.finish::<u128>()
+                        };
+                        Lrc::new(adapted)
+                    } else {
+                        // Nothing to adapt
+                        source_file.clone()
                     }
-                    // expanded code, not from a file
-                    _ => source_file.clone(),
-                }
-            })
-            .map(|mut source_file| {
-                // We're serializing this `SourceFile` into our crate metadata,
-                // so mark it as coming from this crate.
-                // This also ensures that we don't try to deserialize the
-                // `CrateNum` for a proc-macro dependency - since proc macro
-                // dependencies aren't loaded when we deserialize a proc-macro,
-                // trying to remap the `CrateNum` would fail.
-                if self.is_proc_macro {
-                    Lrc::make_mut(&mut source_file).cnum = LOCAL_CRATE;
                 }
-                source_file
-            })
-            .collect::<Vec<_>>();
+                // expanded code, not from a file
+                _ => source_file.clone(),
+            };
+
+            // We're serializing this `SourceFile` into our crate metadata,
+            // so mark it as coming from this crate.
+            // This also ensures that we don't try to deserialize the
+            // `CrateNum` for a proc-macro dependency - since proc macro
+            // dependencies aren't loaded when we deserialize a proc-macro,
+            // trying to remap the `CrateNum` would fail.
+            if self.is_proc_macro {
+                Lrc::make_mut(&mut source_file).cnum = LOCAL_CRATE;
+            }
+
+            let on_disk_index: u32 =
+                on_disk_index.try_into().expect("cannot export more than U32_MAX files");
+            adapted.set(on_disk_index, self.lazy(source_file));
+        }
 
-        self.lazy_array(adapted.iter().map(|rc| &**rc))
+        adapted.encode(&mut self.opaque)
     }
 
     fn encode_crate_root(&mut self) -> LazyValue<CrateRoot> {
@@ -817,6 +847,7 @@ fn should_encode_visibility(def_kind: DefKind) -> bool {
         | DefKind::Use
         | DefKind::ForeignMod
         | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
         | DefKind::Impl
         | DefKind::Field => true,
         DefKind::TyParam
@@ -849,6 +880,7 @@ fn should_encode_stability(def_kind: DefKind) -> bool {
         | DefKind::ForeignMod
         | DefKind::TyAlias
         | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
         | DefKind::Enum
         | DefKind::Union
         | DefKind::Impl
@@ -937,6 +969,7 @@ fn should_encode_variances(def_kind: DefKind) -> bool {
         | DefKind::ForeignMod
         | DefKind::TyAlias
         | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
         | DefKind::Impl
         | DefKind::Trait
         | DefKind::TraitAlias
@@ -973,6 +1006,7 @@ fn should_encode_generics(def_kind: DefKind) -> bool {
         | DefKind::AnonConst
         | DefKind::InlineConst
         | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
         | DefKind::Impl
         | DefKind::Field
         | DefKind::TyParam
@@ -989,6 +1023,103 @@ fn should_encode_generics(def_kind: DefKind) -> bool {
     }
 }
 
+fn should_encode_type(tcx: TyCtxt<'_>, def_id: LocalDefId, def_kind: DefKind) -> bool {
+    match def_kind {
+        DefKind::Struct
+        | DefKind::Union
+        | DefKind::Enum
+        | DefKind::Variant
+        | DefKind::Ctor(..)
+        | DefKind::Field
+        | DefKind::Fn
+        | DefKind::Const
+        | DefKind::Static(..)
+        | DefKind::TyAlias
+        | DefKind::OpaqueTy
+        | DefKind::ForeignTy
+        | DefKind::Impl
+        | DefKind::AssocFn
+        | DefKind::AssocConst
+        | DefKind::Closure
+        | DefKind::Generator
+        | DefKind::ConstParam
+        | DefKind::AnonConst
+        | DefKind::InlineConst => true,
+
+        DefKind::ImplTraitPlaceholder => {
+            let parent_def_id = tcx.impl_trait_in_trait_parent(def_id.to_def_id());
+            let assoc_item = tcx.associated_item(parent_def_id);
+            match assoc_item.container {
+                // Always encode an RPIT in an impl fn, since it always has a body
+                ty::AssocItemContainer::ImplContainer => true,
+                ty::AssocItemContainer::TraitContainer => {
+                    // Encode an RPIT for a trait only if the trait has a default body
+                    assoc_item.defaultness(tcx).has_value()
+                }
+            }
+        }
+
+        DefKind::AssocTy => {
+            let assoc_item = tcx.associated_item(def_id);
+            match assoc_item.container {
+                ty::AssocItemContainer::ImplContainer => true,
+                ty::AssocItemContainer::TraitContainer => assoc_item.defaultness(tcx).has_value(),
+            }
+        }
+        DefKind::TyParam => {
+            let hir::Node::GenericParam(param) = tcx.hir().get_by_def_id(def_id) else { bug!() };
+            let hir::GenericParamKind::Type { default, .. } = param.kind else { bug!() };
+            default.is_some()
+        }
+
+        DefKind::Trait
+        | DefKind::TraitAlias
+        | DefKind::Mod
+        | DefKind::ForeignMod
+        | DefKind::Macro(..)
+        | DefKind::Use
+        | DefKind::LifetimeParam
+        | DefKind::GlobalAsm
+        | DefKind::ExternCrate => false,
+    }
+}
+
+fn should_encode_const(def_kind: DefKind) -> bool {
+    match def_kind {
+        DefKind::Const | DefKind::AssocConst | DefKind::AnonConst => true,
+
+        DefKind::Struct
+        | DefKind::Union
+        | DefKind::Enum
+        | DefKind::Variant
+        | DefKind::Ctor(..)
+        | DefKind::Field
+        | DefKind::Fn
+        | DefKind::Static(..)
+        | DefKind::TyAlias
+        | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
+        | DefKind::ForeignTy
+        | DefKind::Impl
+        | DefKind::AssocFn
+        | DefKind::Closure
+        | DefKind::Generator
+        | DefKind::ConstParam
+        | DefKind::InlineConst
+        | DefKind::AssocTy
+        | DefKind::TyParam
+        | DefKind::Trait
+        | DefKind::TraitAlias
+        | DefKind::Mod
+        | DefKind::ForeignMod
+        | DefKind::Macro(..)
+        | DefKind::Use
+        | DefKind::LifetimeParam
+        | DefKind::GlobalAsm
+        | DefKind::ExternCrate => false,
+    }
+}
+
 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
     fn encode_attrs(&mut self, def_id: LocalDefId) {
         let mut attrs = self
@@ -1014,7 +1145,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             let def_kind = tcx.opt_def_kind(local_id);
             let Some(def_kind) = def_kind else { continue };
             self.tables.opt_def_kind.set(def_id.index, def_kind);
-            record!(self.tables.def_span[def_id] <- tcx.def_span(def_id));
+            let def_span = tcx.def_span(local_id);
+            record!(self.tables.def_span[def_id] <- def_span);
             self.encode_attrs(local_id);
             record!(self.tables.expn_that_defined[def_id] <- self.tcx.expn_that_defined(def_id));
             if let Some(ident_span) = tcx.def_ident_span(def_id) {
@@ -1024,11 +1156,14 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 record!(self.tables.codegen_fn_attrs[def_id] <- self.tcx.codegen_fn_attrs(def_id));
             }
             if should_encode_visibility(def_kind) {
-                record!(self.tables.visibility[def_id] <- self.tcx.visibility(def_id));
+                let vis =
+                    self.tcx.local_visibility(local_id).map_id(|def_id| def_id.local_def_index);
+                record!(self.tables.visibility[def_id] <- vis);
             }
             if should_encode_stability(def_kind) {
                 self.encode_stability(def_id);
                 self.encode_const_stability(def_id);
+                self.encode_default_body_stability(def_id);
                 self.encode_deprecation(def_id);
             }
             if should_encode_variances(def_kind) {
@@ -1044,6 +1179,13 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                     record_array!(self.tables.inferred_outlives_of[def_id] <- inferred_outlives);
                 }
             }
+            if should_encode_type(tcx, local_id, def_kind) {
+                record!(self.tables.type_of[def_id] <- self.tcx.type_of(def_id));
+            }
+            if let DefKind::TyParam = def_kind {
+                let default = self.tcx.object_lifetime_default(def_id);
+                record!(self.tables.object_lifetime_default[def_id] <- default);
+            }
             if let DefKind::Trait | DefKind::TraitAlias = def_kind {
                 record!(self.tables.super_predicates_of[def_id] <- self.tcx.super_predicates_of(def_id));
             }
@@ -1060,11 +1202,6 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         }
     }
 
-    fn encode_item_type(&mut self, def_id: DefId) {
-        debug!("EncodeContext::encode_item_type({:?})", def_id);
-        record!(self.tables.type_of[def_id] <- self.tcx.type_of(def_id));
-    }
-
     fn encode_enum_variant_info(&mut self, def: ty::AdtDef<'tcx>, index: VariantIdx) {
         let tcx = self.tcx;
         let variant = &def.variant(index);
@@ -1078,13 +1215,12 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             is_non_exhaustive: variant.is_field_list_non_exhaustive(),
         };
 
-        record!(self.tables.kind[def_id] <- EntryKind::Variant(self.lazy(data)));
+        record!(self.tables.variant_data[def_id] <- data);
         self.tables.constness.set(def_id.index, hir::Constness::Const);
         record_array!(self.tables.children[def_id] <- variant.fields.iter().map(|f| {
             assert!(f.did.is_local());
             f.did.index
         }));
-        self.encode_item_type(def_id);
         if variant.ctor_kind == CtorKind::Fn {
             // FIXME(eddyb) encode signature only in `encode_enum_variant_ctor`.
             if let Some(ctor_def_id) = variant.ctor_def_id {
@@ -1107,9 +1243,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             is_non_exhaustive: variant.is_field_list_non_exhaustive(),
         };
 
-        record!(self.tables.kind[def_id] <- EntryKind::Variant(self.lazy(data)));
+        record!(self.tables.variant_data[def_id] <- data);
         self.tables.constness.set(def_id.index, hir::Constness::Const);
-        self.encode_item_type(def_id);
         if variant.ctor_kind == CtorKind::Fn {
             record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
         }
@@ -1126,15 +1261,12 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         // code uses it). However, we skip encoding anything relating to child
         // items - we encode information about proc-macros later on.
         let reexports = if !self.is_proc_macro {
-            match tcx.module_reexports(local_def_id) {
-                Some(exports) => self.lazy_array(exports),
-                _ => LazyArray::empty(),
-            }
+            tcx.module_reexports(local_def_id).unwrap_or(&[])
         } else {
-            LazyArray::empty()
+            &[]
         };
 
-        record!(self.tables.kind[def_id] <- EntryKind::Mod(reexports));
+        record_array!(self.tables.module_reexports[def_id] <- reexports);
         if self.is_proc_macro {
             // Encode this here because we don't do it in encode_def_ids.
             record!(self.tables.expn_that_defined[def_id] <- tcx.expn_that_defined(local_def_id));
@@ -1162,22 +1294,6 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         }
     }
 
-    fn encode_field(
-        &mut self,
-        adt_def: ty::AdtDef<'tcx>,
-        variant_index: VariantIdx,
-        field_index: usize,
-    ) {
-        let variant = &adt_def.variant(variant_index);
-        let field = &variant.fields[field_index];
-
-        let def_id = field.did;
-        debug!("EncodeContext::encode_field({:?})", def_id);
-
-        record!(self.tables.kind[def_id] <- EntryKind::Field);
-        self.encode_item_type(def_id);
-    }
-
     fn encode_struct_ctor(&mut self, adt_def: ty::AdtDef<'tcx>, def_id: DefId) {
         debug!("EncodeContext::encode_struct_ctor({:?})", def_id);
         let tcx = self.tcx;
@@ -1191,9 +1307,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         };
 
         record!(self.tables.repr_options[def_id] <- adt_def.repr());
+        record!(self.tables.variant_data[def_id] <- data);
         self.tables.constness.set(def_id.index, hir::Constness::Const);
-        record!(self.tables.kind[def_id] <- EntryKind::Struct(self.lazy(data)));
-        self.encode_item_type(def_id);
         if variant.ctor_kind == CtorKind::Fn {
             record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
         }
@@ -1214,18 +1329,10 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         let ast_item = tcx.hir().expect_trait_item(def_id.expect_local());
         self.tables.impl_defaultness.set(def_id.index, ast_item.defaultness);
         let trait_item = tcx.associated_item(def_id);
+        self.tables.assoc_container.set(def_id.index, trait_item.container);
 
         match trait_item.kind {
-            ty::AssocKind::Const => {
-                let rendered = rustc_hir_pretty::to_string(
-                    &(&self.tcx.hir() as &dyn intravisit::Map<'_>),
-                    |s| s.print_trait_item(ast_item),
-                );
-
-                record!(self.tables.kind[def_id] <- EntryKind::AssocConst(ty::AssocItemContainer::TraitContainer));
-                record!(self.tables.mir_const_qualif[def_id] <- mir::ConstQualifs::default());
-                record!(self.tables.rendered_const[def_id] <- rendered);
-            }
+            ty::AssocKind::Const => {}
             ty::AssocKind::Fn => {
                 let hir::TraitItemKind::Fn(m_sig, m) = &ast_item.kind else { bug!() };
                 match *m {
@@ -1238,24 +1345,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 };
                 self.tables.asyncness.set(def_id.index, m_sig.header.asyncness);
                 self.tables.constness.set(def_id.index, hir::Constness::NotConst);
-                record!(self.tables.kind[def_id] <- EntryKind::AssocFn {
-                    container: ty::AssocItemContainer::TraitContainer,
-                    has_self: trait_item.fn_has_self_parameter,
-                });
             }
             ty::AssocKind::Type => {
                 self.encode_explicit_item_bounds(def_id);
-                record!(self.tables.kind[def_id] <- EntryKind::AssocType(ty::AssocItemContainer::TraitContainer));
-            }
-        }
-        match trait_item.kind {
-            ty::AssocKind::Const | ty::AssocKind::Fn => {
-                self.encode_item_type(def_id);
-            }
-            ty::AssocKind::Type => {
-                if ast_item.defaultness.has_value() {
-                    self.encode_item_type(def_id);
-                }
             }
         }
         if trait_item.kind == ty::AssocKind::Fn {
@@ -1270,20 +1362,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         let ast_item = self.tcx.hir().expect_impl_item(def_id.expect_local());
         self.tables.impl_defaultness.set(def_id.index, ast_item.defaultness);
         let impl_item = self.tcx.associated_item(def_id);
+        self.tables.assoc_container.set(def_id.index, impl_item.container);
 
         match impl_item.kind {
-            ty::AssocKind::Const => {
-                if let hir::ImplItemKind::Const(_, body_id) = ast_item.kind {
-                    let qualifs = self.tcx.at(ast_item.span).mir_const_qualif(def_id);
-                    let const_data = self.encode_rendered_const_for_body(body_id);
-
-                    record!(self.tables.kind[def_id] <- EntryKind::AssocConst(ty::AssocItemContainer::ImplContainer));
-                    record!(self.tables.mir_const_qualif[def_id] <- qualifs);
-                    record!(self.tables.rendered_const[def_id] <- const_data);
-                } else {
-                    bug!()
-                }
-            }
             ty::AssocKind::Fn => {
                 let hir::ImplItemKind::Fn(ref sig, body) = ast_item.kind else { bug!() };
                 self.tables.asyncness.set(def_id.index, sig.header.asyncness);
@@ -1295,16 +1376,9 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                     hir::Constness::NotConst
                 };
                 self.tables.constness.set(def_id.index, constness);
-                record!(self.tables.kind[def_id] <- EntryKind::AssocFn {
-                    container: ty::AssocItemContainer::ImplContainer,
-                    has_self: impl_item.fn_has_self_parameter,
-                });
-            }
-            ty::AssocKind::Type => {
-                record!(self.tables.kind[def_id] <- EntryKind::AssocType(ty::AssocItemContainer::ImplContainer));
             }
+            ty::AssocKind::Const | ty::AssocKind::Type => {}
         }
-        self.encode_item_type(def_id);
         if let Some(trait_item_def_id) = impl_item.trait_item_def_id {
             self.tables.trait_item_def_id.set(def_id.index, trait_item_def_id.into());
         }
@@ -1321,40 +1395,43 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             return;
         }
 
-        let keys_and_jobs = self
-            .tcx
-            .mir_keys(())
-            .iter()
-            .filter_map(|&def_id| {
-                let (encode_const, encode_opt) = should_encode_mir(self.tcx, def_id);
-                if encode_const || encode_opt {
-                    Some((def_id, encode_const, encode_opt))
-                } else {
-                    None
-                }
-            })
-            .collect::<Vec<_>>();
-        for (def_id, encode_const, encode_opt) in keys_and_jobs.into_iter() {
+        let tcx = self.tcx;
+
+        let keys_and_jobs = tcx.mir_keys(()).iter().filter_map(|&def_id| {
+            let (encode_const, encode_opt) = should_encode_mir(tcx, def_id);
+            if encode_const || encode_opt { Some((def_id, encode_const, encode_opt)) } else { None }
+        });
+        for (def_id, encode_const, encode_opt) in keys_and_jobs {
             debug_assert!(encode_const || encode_opt);
 
             debug!("EntryBuilder::encode_mir({:?})", def_id);
             if encode_opt {
-                record!(self.tables.optimized_mir[def_id.to_def_id()] <- self.tcx.optimized_mir(def_id));
+                record!(self.tables.optimized_mir[def_id.to_def_id()] <- tcx.optimized_mir(def_id));
             }
             if encode_const {
-                record!(self.tables.mir_for_ctfe[def_id.to_def_id()] <- self.tcx.mir_for_ctfe(def_id));
+                record!(self.tables.mir_for_ctfe[def_id.to_def_id()] <- tcx.mir_for_ctfe(def_id));
 
                 // FIXME(generic_const_exprs): this feels wrong to have in `encode_mir`
-                let abstract_const = self.tcx.thir_abstract_const(def_id);
+                let abstract_const = tcx.thir_abstract_const(def_id);
                 if let Ok(Some(abstract_const)) = abstract_const {
                     record!(self.tables.thir_abstract_const[def_id.to_def_id()] <- abstract_const);
                 }
+
+                if should_encode_const(tcx.def_kind(def_id)) {
+                    let qualifs = tcx.mir_const_qualif(def_id);
+                    record!(self.tables.mir_const_qualif[def_id.to_def_id()] <- qualifs);
+                    let body_id = tcx.hir().maybe_body_owned_by(def_id);
+                    if let Some(body_id) = body_id {
+                        let const_data = self.encode_rendered_const_for_body(body_id);
+                        record!(self.tables.rendered_const[def_id.to_def_id()] <- const_data);
+                    }
+                }
             }
-            record!(self.tables.promoted_mir[def_id.to_def_id()] <- self.tcx.promoted_mir(def_id));
+            record!(self.tables.promoted_mir[def_id.to_def_id()] <- tcx.promoted_mir(def_id));
 
             let instance =
                 ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id.to_def_id()));
-            let unused = self.tcx.unused_generic_params(instance);
+            let unused = tcx.unused_generic_params(instance);
             if !unused.is_empty() {
                 record!(self.tables.unused_generic_params[def_id.to_def_id()] <- unused);
             }
@@ -1385,6 +1462,18 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         }
     }
 
+    fn encode_default_body_stability(&mut self, def_id: DefId) {
+        debug!("EncodeContext::encode_default_body_stability({:?})", def_id);
+
+        // The query lookup can take a measurable amount of time in crates with many items. Check if
+        // the stability attributes are even enabled before using their queries.
+        if self.feat.staged_api || self.tcx.sess.opts.unstable_opts.force_unstable_if_unmarked {
+            if let Some(stab) = self.tcx.lookup_default_body_stability(def_id) {
+                record!(self.tables.lookup_default_body_stability[def_id] <- stab)
+            }
+        }
+    }
+
     fn encode_deprecation(&mut self, def_id: DefId) {
         debug!("EncodeContext::encode_deprecation({:?})", def_id);
         if let Some(depr) = self.tcx.lookup_deprecation(def_id) {
@@ -1405,38 +1494,27 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
 
         debug!("EncodeContext::encode_info_for_item({:?})", def_id);
 
-        let entry_kind = match item.kind {
-            hir::ItemKind::Static(..) => EntryKind::Static,
-            hir::ItemKind::Const(_, body_id) => {
-                let qualifs = self.tcx.at(item.span).mir_const_qualif(def_id);
-                let const_data = self.encode_rendered_const_for_body(body_id);
-                record!(self.tables.mir_const_qualif[def_id] <- qualifs);
-                record!(self.tables.rendered_const[def_id] <- const_data);
-                EntryKind::Const
-            }
+        match item.kind {
             hir::ItemKind::Fn(ref sig, .., body) => {
                 self.tables.asyncness.set(def_id.index, sig.header.asyncness);
                 record_array!(self.tables.fn_arg_names[def_id] <- self.tcx.hir().body_param_names(body));
                 self.tables.constness.set(def_id.index, sig.header.constness);
-                EntryKind::Fn
             }
             hir::ItemKind::Macro(ref macro_def, _) => {
-                EntryKind::MacroDef(self.lazy(&*macro_def.body), macro_def.macro_rules)
+                if macro_def.macro_rules {
+                    self.tables.macro_rules.set(def_id.index, ());
+                }
+                record!(self.tables.macro_definition[def_id] <- &*macro_def.body);
             }
             hir::ItemKind::Mod(ref m) => {
                 return self.encode_info_for_mod(item.def_id, m);
             }
-            hir::ItemKind::ForeignMod { .. } => EntryKind::ForeignMod,
-            hir::ItemKind::GlobalAsm(..) => EntryKind::GlobalAsm,
-            hir::ItemKind::TyAlias(..) => EntryKind::Type,
             hir::ItemKind::OpaqueTy(..) => {
                 self.encode_explicit_item_bounds(def_id);
-                EntryKind::OpaqueTy
             }
             hir::ItemKind::Enum(..) => {
                 let adt_def = self.tcx.adt_def(def_id);
                 record!(self.tables.repr_options[def_id] <- adt_def.repr());
-                EntryKind::Enum
             }
             hir::ItemKind::Struct(ref struct_def, _) => {
                 let adt_def = self.tcx.adt_def(def_id);
@@ -1451,24 +1529,24 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                     .map(|ctor_hir_id| self.tcx.hir().local_def_id(ctor_hir_id).local_def_index);
 
                 let variant = adt_def.non_enum_variant();
-                EntryKind::Struct(self.lazy(VariantData {
+                record!(self.tables.variant_data[def_id] <- VariantData {
                     ctor_kind: variant.ctor_kind,
                     discr: variant.discr,
                     ctor,
                     is_non_exhaustive: variant.is_field_list_non_exhaustive(),
-                }))
+                });
             }
             hir::ItemKind::Union(..) => {
                 let adt_def = self.tcx.adt_def(def_id);
                 record!(self.tables.repr_options[def_id] <- adt_def.repr());
 
                 let variant = adt_def.non_enum_variant();
-                EntryKind::Union(self.lazy(VariantData {
+                record!(self.tables.variant_data[def_id] <- VariantData {
                     ctor_kind: variant.ctor_kind,
                     discr: variant.discr,
                     ctor: None,
                     is_non_exhaustive: variant.is_field_list_non_exhaustive(),
-                }))
+                });
             }
             hir::ItemKind::Impl(hir::Impl { defaultness, constness, .. }) => {
                 self.tables.impl_defaultness.set(def_id.index, *defaultness);
@@ -1494,26 +1572,24 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
 
                 let polarity = self.tcx.impl_polarity(def_id);
                 self.tables.impl_polarity.set(def_id.index, polarity);
-
-                EntryKind::Impl
             }
             hir::ItemKind::Trait(..) => {
                 let trait_def = self.tcx.trait_def(def_id);
                 record!(self.tables.trait_def[def_id] <- trait_def);
-
-                EntryKind::Trait
             }
             hir::ItemKind::TraitAlias(..) => {
                 let trait_def = self.tcx.trait_def(def_id);
                 record!(self.tables.trait_def[def_id] <- trait_def);
-
-                EntryKind::TraitAlias
             }
             hir::ItemKind::ExternCrate(_) | hir::ItemKind::Use(..) => {
                 bug!("cannot encode info for item {:?}", item)
             }
+            hir::ItemKind::Static(..)
+            | hir::ItemKind::Const(..)
+            | hir::ItemKind::ForeignMod { .. }
+            | hir::ItemKind::GlobalAsm(..)
+            | hir::ItemKind::TyAlias(..) => {}
         };
-        record!(self.tables.kind[def_id] <- entry_kind);
         // FIXME(eddyb) there should be a nicer way to do this.
         match item.kind {
             hir::ItemKind::Enum(..) => record_array!(self.tables.children[def_id] <-
@@ -1541,18 +1617,6 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             }
             _ => {}
         }
-        match item.kind {
-            hir::ItemKind::Static(..)
-            | hir::ItemKind::Const(..)
-            | hir::ItemKind::Fn(..)
-            | hir::ItemKind::TyAlias(..)
-            | hir::ItemKind::OpaqueTy(..)
-            | hir::ItemKind::Enum(..)
-            | hir::ItemKind::Struct(..)
-            | hir::ItemKind::Union(..)
-            | hir::ItemKind::Impl { .. } => self.encode_item_type(def_id),
-            _ => {}
-        }
         if let hir::ItemKind::Fn(..) = item.kind {
             record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
             if tcx.is_intrinsic(def_id) {
@@ -1564,12 +1628,43 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 record!(self.tables.impl_trait_ref[def_id] <- trait_ref);
             }
         }
-    }
+        // In some cases, along with the item itself, we also
+        // encode some sub-items. Usually we want some info from the item
+        // so it's easier to do that here then to wait until we would encounter
+        // normally in the visitor walk.
+        match item.kind {
+            hir::ItemKind::Enum(..) => {
+                let def = self.tcx.adt_def(item.def_id.to_def_id());
+                for (i, variant) in def.variants().iter_enumerated() {
+                    self.encode_enum_variant_info(def, i);
 
-    fn encode_info_for_generic_param(&mut self, def_id: DefId, kind: EntryKind, encode_type: bool) {
-        record!(self.tables.kind[def_id] <- kind);
-        if encode_type {
-            self.encode_item_type(def_id);
+                    if let Some(_ctor_def_id) = variant.ctor_def_id {
+                        self.encode_enum_variant_ctor(def, i);
+                    }
+                }
+            }
+            hir::ItemKind::Struct(ref struct_def, _) => {
+                let def = self.tcx.adt_def(item.def_id.to_def_id());
+                // If the struct has a constructor, encode it.
+                if let Some(ctor_hir_id) = struct_def.ctor_hir_id() {
+                    let ctor_def_id = self.tcx.hir().local_def_id(ctor_hir_id);
+                    self.encode_struct_ctor(def, ctor_def_id.to_def_id());
+                }
+            }
+            hir::ItemKind::Impl { .. } => {
+                for &trait_item_def_id in
+                    self.tcx.associated_item_def_ids(item.def_id.to_def_id()).iter()
+                {
+                    self.encode_info_for_impl_item(trait_item_def_id);
+                }
+            }
+            hir::ItemKind::Trait(..) => {
+                for &item_def_id in self.tcx.associated_item_def_ids(item.def_id.to_def_id()).iter()
+                {
+                    self.encode_info_for_trait_item(item_def_id);
+                }
+            }
+            _ => {}
         }
     }
 
@@ -1584,34 +1679,16 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             ty::Generator(..) => {
                 let data = self.tcx.generator_kind(def_id).unwrap();
                 let generator_diagnostic_data = typeck_result.get_generator_diagnostic_data();
-                record!(self.tables.kind[def_id.to_def_id()] <- EntryKind::Generator);
                 record!(self.tables.generator_kind[def_id.to_def_id()] <- data);
                 record!(self.tables.generator_diagnostic_data[def_id.to_def_id()]  <- generator_diagnostic_data);
             }
 
-            ty::Closure(..) => {
-                record!(self.tables.kind[def_id.to_def_id()] <- EntryKind::Closure);
+            ty::Closure(_, substs) => {
+                record!(self.tables.fn_sig[def_id.to_def_id()] <- substs.as_closure().sig());
             }
 
             _ => bug!("closure that is neither generator nor closure"),
         }
-        self.encode_item_type(def_id.to_def_id());
-        if let ty::Closure(def_id, substs) = *ty.kind() {
-            record!(self.tables.fn_sig[def_id] <- substs.as_closure().sig());
-        }
-    }
-
-    fn encode_info_for_anon_const(&mut self, id: hir::HirId) {
-        let def_id = self.tcx.hir().local_def_id(id);
-        debug!("EncodeContext::encode_info_for_anon_const({:?})", def_id);
-        let body_id = self.tcx.hir().body_owned_by(def_id);
-        let const_data = self.encode_rendered_const_for_body(body_id);
-        let qualifs = self.tcx.mir_const_qualif(def_id);
-
-        record!(self.tables.kind[def_id.to_def_id()] <- EntryKind::AnonConst);
-        record!(self.tables.mir_const_qualif[def_id.to_def_id()] <- qualifs);
-        record!(self.tables.rendered_const[def_id.to_def_id()] <- const_data);
-        self.encode_item_type(def_id.to_def_id());
     }
 
     fn encode_native_libraries(&mut self) -> LazyArray<NativeLib> {
@@ -1670,7 +1747,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             self.tables.opt_def_kind.set(LOCAL_CRATE.as_def_id().index, DefKind::Mod);
             record!(self.tables.def_span[LOCAL_CRATE.as_def_id()] <- tcx.def_span(LOCAL_CRATE.as_def_id()));
             self.encode_attrs(LOCAL_CRATE.as_def_id().expect_local());
-            record!(self.tables.visibility[LOCAL_CRATE.as_def_id()] <- tcx.visibility(LOCAL_CRATE.as_def_id()));
+            let vis = tcx.local_visibility(CRATE_DEF_ID).map_id(|def_id| def_id.local_def_index);
+            record!(self.tables.visibility[LOCAL_CRATE.as_def_id()] <- vis);
             if let Some(stability) = stability {
                 record!(self.tables.lookup_stability[LOCAL_CRATE.as_def_id()] <- stability);
             }
@@ -1709,7 +1787,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
 
                 let def_id = id.to_def_id();
                 self.tables.opt_def_kind.set(def_id.index, DefKind::Macro(macro_kind));
-                record!(self.tables.kind[def_id] <- EntryKind::ProcMacro(macro_kind));
+                self.tables.proc_macro.set(def_id.index, macro_kind);
                 self.encode_attrs(id);
                 record!(self.tables.def_keys[def_id] <- def_key);
                 record!(self.tables.def_ident_span[def_id] <- span);
@@ -1947,18 +2025,11 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                     hir::Constness::NotConst
                 };
                 self.tables.constness.set(def_id.index, constness);
-                record!(self.tables.kind[def_id] <- EntryKind::ForeignFn);
-            }
-            hir::ForeignItemKind::Static(..) => {
-                record!(self.tables.kind[def_id] <- EntryKind::ForeignStatic);
-            }
-            hir::ForeignItemKind::Type => {
-                record!(self.tables.kind[def_id] <- EntryKind::ForeignType);
+                record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
             }
+            hir::ForeignItemKind::Static(..) | hir::ForeignItemKind::Type => {}
         }
-        self.encode_item_type(def_id);
         if let hir::ForeignItemKind::Fn(..) = nitem.kind {
-            record!(self.tables.fn_sig[def_id] <- tcx.fn_sig(def_id));
             if tcx.is_intrinsic(def_id) {
                 self.tables.is_intrinsic.set(def_id.index, ());
             }
@@ -1977,17 +2048,12 @@ impl<'a, 'tcx> Visitor<'tcx> for EncodeContext<'a, 'tcx> {
         intravisit::walk_expr(self, ex);
         self.encode_info_for_expr(ex);
     }
-    fn visit_anon_const(&mut self, c: &'tcx AnonConst) {
-        intravisit::walk_anon_const(self, c);
-        self.encode_info_for_anon_const(c.hir_id);
-    }
     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
         intravisit::walk_item(self, item);
         match item.kind {
             hir::ItemKind::ExternCrate(_) | hir::ItemKind::Use(..) => {} // ignore these
             _ => self.encode_info_for_item(item.def_id.to_def_id(), item),
         }
-        self.encode_addl_info_for_item(item);
     }
     fn visit_foreign_item(&mut self, ni: &'tcx hir::ForeignItem<'tcx>) {
         intravisit::walk_foreign_item(self, ni);
@@ -2000,29 +2066,13 @@ impl<'a, 'tcx> Visitor<'tcx> for EncodeContext<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
-    fn encode_fields(&mut self, adt_def: ty::AdtDef<'tcx>) {
-        for (variant_index, variant) in adt_def.variants().iter_enumerated() {
-            for (field_index, _field) in variant.fields.iter().enumerate() {
-                self.encode_field(adt_def, variant_index, field_index);
-            }
-        }
-    }
-
     fn encode_info_for_generics(&mut self, generics: &hir::Generics<'tcx>) {
         for param in generics.params {
             let def_id = self.tcx.hir().local_def_id(param.hir_id);
             match param.kind {
-                GenericParamKind::Lifetime { .. } => continue,
-                GenericParamKind::Type { default, .. } => {
-                    self.encode_info_for_generic_param(
-                        def_id.to_def_id(),
-                        EntryKind::TypeParam,
-                        default.is_some(),
-                    );
-                }
-                GenericParamKind::Const { ref default, .. } => {
+                hir::GenericParamKind::Lifetime { .. } | hir::GenericParamKind::Type { .. } => {}
+                hir::GenericParamKind::Const { ref default, .. } => {
                     let def_id = def_id.to_def_id();
-                    self.encode_info_for_generic_param(def_id, EntryKind::ConstParam, true);
                     if default.is_some() {
                         record!(self.tables.const_param_default[def_id] <- self.tcx.const_param_default(def_id))
                     }
@@ -2036,68 +2086,6 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             self.encode_info_for_closure(expr.hir_id);
         }
     }
-
-    /// In some cases, along with the item itself, we also
-    /// encode some sub-items. Usually we want some info from the item
-    /// so it's easier to do that here then to wait until we would encounter
-    /// normally in the visitor walk.
-    fn encode_addl_info_for_item(&mut self, item: &hir::Item<'_>) {
-        match item.kind {
-            hir::ItemKind::Static(..)
-            | hir::ItemKind::Const(..)
-            | hir::ItemKind::Fn(..)
-            | hir::ItemKind::Macro(..)
-            | hir::ItemKind::Mod(..)
-            | hir::ItemKind::ForeignMod { .. }
-            | hir::ItemKind::GlobalAsm(..)
-            | hir::ItemKind::ExternCrate(..)
-            | hir::ItemKind::Use(..)
-            | hir::ItemKind::TyAlias(..)
-            | hir::ItemKind::OpaqueTy(..)
-            | hir::ItemKind::TraitAlias(..) => {
-                // no sub-item recording needed in these cases
-            }
-            hir::ItemKind::Enum(..) => {
-                let def = self.tcx.adt_def(item.def_id.to_def_id());
-                self.encode_fields(def);
-
-                for (i, variant) in def.variants().iter_enumerated() {
-                    self.encode_enum_variant_info(def, i);
-
-                    if let Some(_ctor_def_id) = variant.ctor_def_id {
-                        self.encode_enum_variant_ctor(def, i);
-                    }
-                }
-            }
-            hir::ItemKind::Struct(ref struct_def, _) => {
-                let def = self.tcx.adt_def(item.def_id.to_def_id());
-                self.encode_fields(def);
-
-                // If the struct has a constructor, encode it.
-                if let Some(ctor_hir_id) = struct_def.ctor_hir_id() {
-                    let ctor_def_id = self.tcx.hir().local_def_id(ctor_hir_id);
-                    self.encode_struct_ctor(def, ctor_def_id.to_def_id());
-                }
-            }
-            hir::ItemKind::Union(..) => {
-                let def = self.tcx.adt_def(item.def_id.to_def_id());
-                self.encode_fields(def);
-            }
-            hir::ItemKind::Impl { .. } => {
-                for &trait_item_def_id in
-                    self.tcx.associated_item_def_ids(item.def_id.to_def_id()).iter()
-                {
-                    self.encode_info_for_impl_item(trait_item_def_id);
-                }
-            }
-            hir::ItemKind::Trait(..) => {
-                for &item_def_id in self.tcx.associated_item_def_ids(item.def_id.to_def_id()).iter()
-                {
-                    self.encode_info_for_trait_item(item_def_id);
-                }
-            }
-        }
-    }
 }
 
 /// Used to prefetch queries which will be needed later by metadata encoding.
@@ -2220,7 +2208,7 @@ pub fn encode_metadata(tcx: TyCtxt<'_>, path: &Path) {
 
 fn encode_metadata_impl(tcx: TyCtxt<'_>, path: &Path) {
     let mut encoder = opaque::FileEncoder::new(path)
-        .unwrap_or_else(|err| tcx.sess.fatal(&format!("failed to create file encoder: {}", err)));
+        .unwrap_or_else(|err| tcx.sess.emit_fatal(FailCreateFileEncoder { err }));
     encoder.emit_raw_bytes(METADATA_HEADER);
 
     // Will be filled with the root position after encoding everything.
@@ -2228,7 +2216,7 @@ fn encode_metadata_impl(tcx: TyCtxt<'_>, path: &Path) {
 
     let source_map_files = tcx.sess.source_map().files();
     let source_file_cache = (source_map_files[0].clone(), 0);
-    let required_source_files = Some(GrowableBitSet::with_capacity(source_map_files.len()));
+    let required_source_files = Some(FxIndexSet::default());
     drop(source_map_files);
 
     let hygiene_ctxt = HygieneEncodeContext::default();
@@ -2246,6 +2234,7 @@ fn encode_metadata_impl(tcx: TyCtxt<'_>, path: &Path) {
         required_source_files,
         is_proc_macro: tcx.sess.crate_types().contains(&CrateType::ProcMacro),
         hygiene_ctxt: &hygiene_ctxt,
+        symbol_table: Default::default(),
     };
 
     // Encode the rustc version string in a predictable location.
@@ -2264,10 +2253,10 @@ fn encode_metadata_impl(tcx: TyCtxt<'_>, path: &Path) {
     // Encode the root position.
     let header = METADATA_HEADER.len();
     file.seek(std::io::SeekFrom::Start(header as u64))
-        .unwrap_or_else(|err| tcx.sess.fatal(&format!("failed to seek the file: {}", err)));
+        .unwrap_or_else(|err| tcx.sess.emit_fatal(FailSeekFile { err }));
     let pos = root.position.get();
     file.write_all(&[(pos >> 24) as u8, (pos >> 16) as u8, (pos >> 8) as u8, (pos >> 0) as u8])
-        .unwrap_or_else(|err| tcx.sess.fatal(&format!("failed to write to the file: {}", err)));
+        .unwrap_or_else(|err| tcx.sess.emit_fatal(FailWriteFile { err }));
 
     // Return to the position where we are before writing the root position.
     file.seek(std::io::SeekFrom::Start(pos_before_seek)).unwrap();
diff --git a/compiler/rustc_metadata/src/rmeta/mod.rs b/compiler/rustc_metadata/src/rmeta/mod.rs
index 66bdecc30..748b3afec 100644
--- a/compiler/rustc_metadata/src/rmeta/mod.rs
+++ b/compiler/rustc_metadata/src/rmeta/mod.rs
@@ -16,6 +16,7 @@ use rustc_index::{bit_set::FiniteBitSet, vec::IndexVec};
 use rustc_middle::metadata::ModChild;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
 use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportInfo};
+use rustc_middle::middle::resolve_lifetime::ObjectLifetimeDefault;
 use rustc_middle::mir;
 use rustc_middle::ty::fast_reject::SimplifiedType;
 use rustc_middle::ty::query::Providers;
@@ -249,7 +250,7 @@ pub(crate) struct CrateRoot {
 
     def_path_hash_map: LazyValue<DefPathHashMapRef<'static>>,
 
-    source_map: LazyArray<rustc_span::SourceFile>,
+    source_map: LazyTable<u32, LazyValue<rustc_span::SourceFile>>,
 
     compiler_builtins: bool,
     needs_allocator: bool,
@@ -333,16 +334,16 @@ macro_rules! define_tables {
 }
 
 define_tables! {
-    kind: Table<DefIndex, LazyValue<EntryKind>>,
     attributes: Table<DefIndex, LazyArray<ast::Attribute>>,
     children: Table<DefIndex, LazyArray<DefIndex>>,
 
     opt_def_kind: Table<DefIndex, DefKind>,
-    visibility: Table<DefIndex, LazyValue<ty::Visibility>>,
+    visibility: Table<DefIndex, LazyValue<ty::Visibility<DefIndex>>>,
     def_span: Table<DefIndex, LazyValue<Span>>,
     def_ident_span: Table<DefIndex, LazyValue<Span>>,
     lookup_stability: Table<DefIndex, LazyValue<attr::Stability>>,
     lookup_const_stability: Table<DefIndex, LazyValue<attr::ConstStability>>,
+    lookup_default_body_stability: Table<DefIndex, LazyValue<attr::DefaultBodyStability>>,
     lookup_deprecation_entry: Table<DefIndex, LazyValue<attr::Deprecation>>,
     // As an optimization, a missing entry indicates an empty `&[]`.
     explicit_item_bounds: Table<DefIndex, LazyArray<(ty::Predicate<'static>, Span)>>,
@@ -357,6 +358,7 @@ define_tables! {
     codegen_fn_attrs: Table<DefIndex, LazyValue<CodegenFnAttrs>>,
     impl_trait_ref: Table<DefIndex, LazyValue<ty::TraitRef<'static>>>,
     const_param_default: Table<DefIndex, LazyValue<rustc_middle::ty::Const<'static>>>,
+    object_lifetime_default: Table<DefIndex, LazyValue<ObjectLifetimeDefault>>,
     optimized_mir: Table<DefIndex, LazyValue<mir::Body<'static>>>,
     mir_for_ctfe: Table<DefIndex, LazyValue<mir::Body<'static>>>,
     promoted_mir: Table<DefIndex, LazyValue<IndexVec<mir::Promoted, mir::Body<'static>>>>,
@@ -390,39 +392,13 @@ define_tables! {
     proc_macro_quoted_spans: Table<usize, LazyValue<Span>>,
     generator_diagnostic_data: Table<DefIndex, LazyValue<GeneratorDiagnosticData<'static>>>,
     may_have_doc_links: Table<DefIndex, ()>,
-}
-
-#[derive(Copy, Clone, MetadataEncodable, MetadataDecodable)]
-enum EntryKind {
-    AnonConst,
-    Const,
-    Static,
-    ForeignStatic,
-    ForeignMod,
-    ForeignType,
-    GlobalAsm,
-    Type,
-    TypeParam,
-    ConstParam,
-    OpaqueTy,
-    Enum,
-    Field,
-    Variant(LazyValue<VariantData>),
-    Struct(LazyValue<VariantData>),
-    Union(LazyValue<VariantData>),
-    Fn,
-    ForeignFn,
-    Mod(LazyArray<ModChild>),
-    MacroDef(LazyValue<ast::MacArgs>, /*macro_rules*/ bool),
-    ProcMacro(MacroKind),
-    Closure,
-    Generator,
-    Trait,
-    Impl,
-    AssocFn { container: ty::AssocItemContainer, has_self: bool },
-    AssocType(ty::AssocItemContainer),
-    AssocConst(ty::AssocItemContainer),
-    TraitAlias,
+    variant_data: Table<DefIndex, LazyValue<VariantData>>,
+    assoc_container: Table<DefIndex, ty::AssocItemContainer>,
+    // Slot is full when macro is macro_rules.
+    macro_rules: Table<DefIndex, ()>,
+    macro_definition: Table<DefIndex, LazyValue<ast::MacArgs>>,
+    proc_macro: Table<DefIndex, MacroKind>,
+    module_reexports: Table<DefIndex, LazyArray<ModChild>>,
 }
 
 #[derive(TyEncodable, TyDecodable)]
@@ -444,6 +420,11 @@ const TAG_VALID_SPAN_LOCAL: u8 = 0;
 const TAG_VALID_SPAN_FOREIGN: u8 = 1;
 const TAG_PARTIAL_SPAN: u8 = 2;
 
+// Tags for encoding Symbol's
+const SYMBOL_STR: u8 = 0;
+const SYMBOL_OFFSET: u8 = 1;
+const SYMBOL_PREINTERNED: u8 = 2;
+
 pub fn provide(providers: &mut Providers) {
     encoder::provide(providers);
     decoder::provide(providers);
@@ -451,7 +432,6 @@ pub fn provide(providers: &mut Providers) {
 
 trivially_parameterized_over_tcx! {
     VariantData,
-    EntryKind,
     RawDefId,
     TraitImpls,
     IncoherentImpls,
diff --git a/compiler/rustc_metadata/src/rmeta/table.rs b/compiler/rustc_metadata/src/rmeta/table.rs
index 21841ae25..e7c1abd12 100644
--- a/compiler/rustc_metadata/src/rmeta/table.rs
+++ b/compiler/rustc_metadata/src/rmeta/table.rs
@@ -10,7 +10,6 @@ use rustc_span::hygiene::MacroKind;
 use std::convert::TryInto;
 use std::marker::PhantomData;
 use std::num::NonZeroUsize;
-use tracing::debug;
 
 /// Helper trait, for encoding to, and decoding from, a fixed number of bytes.
 /// Used mainly for Lazy positions and lengths.
@@ -51,7 +50,7 @@ macro_rules! fixed_size_enum {
                 }
                 match b[0] - 1 {
                     $(${index()} => Some($($pat)*),)*
-                    _ => panic!("Unexpected ImplPolarity code: {:?}", b[0]),
+                    _ => panic!("Unexpected {} code: {:?}", stringify!($ty), b[0]),
                 }
             }
 
@@ -91,6 +90,7 @@ fixed_size_enum! {
         ( AnonConst                                )
         ( InlineConst                              )
         ( OpaqueTy                                 )
+        ( ImplTraitPlaceholder                     )
         ( Field                                    )
         ( LifetimeParam                            )
         ( GlobalAsm                                )
@@ -141,6 +141,21 @@ fixed_size_enum! {
     }
 }
 
+fixed_size_enum! {
+    ty::AssocItemContainer {
+        ( TraitContainer )
+        ( ImplContainer  )
+    }
+}
+
+fixed_size_enum! {
+    MacroKind {
+        ( Attr   )
+        ( Bang   )
+        ( Derive )
+    }
+}
+
 // We directly encode `DefPathHash` because a `LazyValue` would incur a 25% cost.
 impl FixedSizeEncoding for Option<DefPathHash> {
     type ByteArray = [u8; 16];