1 files changed, 27 insertions, 14 deletions

diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index 84b89cd71..4f396e970 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -22,7 +22,6 @@ use rustc_data_structures::sync::ParallelIterator;
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_hir::lang_items::LangItem;
-use rustc_hir::weak_lang_items::WEAK_ITEMS_SYMBOLS;
 use rustc_index::vec::Idx;
 use rustc_metadata::EncodedMetadata;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
@@ -639,7 +638,14 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
         let llmod_id =
             cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("allocator")).to_string();
         let module_llvm = tcx.sess.time("write_allocator_module", || {
-            backend.codegen_allocator(tcx, &llmod_id, kind, tcx.lang_items().oom().is_some())
+            backend.codegen_allocator(
+                tcx,
+                &llmod_id,
+                kind,
+                // If allocator_kind is Some then alloc_error_handler_kind must
+                // also be Some.
+                tcx.alloc_error_handler_kind(()).unwrap(),
+            )
         });
 
         Some(ModuleCodegen { name: llmod_id, module_llvm, kind: ModuleKind::Allocator })
@@ -827,20 +833,30 @@ impl CrateInfo {
         //
         // In order to get this left-to-right dependency ordering, we use the reverse
         // postorder of all crates putting the leaves at the right-most positions.
-        let used_crates = tcx
+        let mut compiler_builtins = None;
+        let mut used_crates: Vec<_> = tcx
             .postorder_cnums(())
             .iter()
             .rev()
             .copied()
-            .filter(|&cnum| !tcx.dep_kind(cnum).macros_only())
+            .filter(|&cnum| {
+                let link = !tcx.dep_kind(cnum).macros_only();
+                if link && tcx.is_compiler_builtins(cnum) {
+                    compiler_builtins = Some(cnum);
+                    return false;
+                }
+                link
+            })
             .collect();
+        // `compiler_builtins` are always placed last to ensure that they're linked correctly.
+        used_crates.extend(compiler_builtins);
 
         let mut info = CrateInfo {
             target_cpu,
             exported_symbols,
             linked_symbols,
             local_crate_name,
-            compiler_builtins: None,
+            compiler_builtins,
             profiler_runtime: None,
             is_no_builtins: Default::default(),
             native_libraries: Default::default(),
@@ -866,9 +882,6 @@ impl CrateInfo {
 
             let used_crate_source = tcx.used_crate_source(cnum);
             info.used_crate_source.insert(cnum, used_crate_source.clone());
-            if tcx.is_compiler_builtins(cnum) {
-                info.compiler_builtins = Some(cnum);
-            }
             if tcx.is_profiler_runtime(cnum) {
                 info.profiler_runtime = Some(cnum);
             }
@@ -887,14 +900,14 @@ impl CrateInfo {
         // by the compiler, but that's ok because all this stuff is unstable anyway.
         let target = &tcx.sess.target;
         if !are_upstream_rust_objects_already_included(tcx.sess) {
-            let missing_weak_lang_items: FxHashSet<&Symbol> = info
+            let missing_weak_lang_items: FxHashSet<Symbol> = info
                 .used_crates
                 .iter()
-                .flat_map(|cnum| {
-                    tcx.missing_lang_items(*cnum)
-                        .iter()
-                        .filter(|l| lang_items::required(tcx, **l))
-                        .filter_map(|item| WEAK_ITEMS_SYMBOLS.get(item))
+                .flat_map(|&cnum| tcx.missing_lang_items(cnum))
+                .filter(|l| l.is_weak())
+                .filter_map(|&l| {
+                    let name = l.link_name()?;
+                    lang_items::required(tcx, l).then_some(name)
                 })
                 .collect();
             let prefix = if target.is_like_windows && target.arch == "x86" { "_" } else { "" };