Merging upstream version 1.75.0+dfsg1.

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

4 files changed, 119 insertions, 50 deletions

diff --git a/compiler/rustc_const_eval/src/util/alignment.rs b/compiler/rustc_const_eval/src/util/alignment.rs
index 2e0643afb..8642dfccd 100644
--- a/compiler/rustc_const_eval/src/util/alignment.rs
+++ b/compiler/rustc_const_eval/src/util/alignment.rs
@@ -21,10 +21,18 @@ where
     };
 
     let ty = place.ty(local_decls, tcx).ty;
+    let unsized_tail = || tcx.struct_tail_with_normalize(ty, |ty| ty, || {});
     match tcx.layout_of(param_env.and(ty)) {
-        Ok(layout) if layout.align.abi <= pack => {
+        Ok(layout)
+            if layout.align.abi <= pack
+                && (layout.is_sized()
+                    || matches!(unsized_tail().kind(), ty::Slice(..) | ty::Str)) =>
+        {
             // If the packed alignment is greater or equal to the field alignment, the type won't be
             // further disaligned.
+            // However we need to ensure the field is sized; for unsized fields, `layout.align` is
+            // just an approximation -- except when the unsized tail is a slice, where the alignment
+            // is fully determined by the type.
             debug!(
                 "is_disaligned({:?}) - align = {}, packed = {}; not disaligned",
                 place,
diff --git a/compiler/rustc_const_eval/src/util/caller_location.rs b/compiler/rustc_const_eval/src/util/caller_location.rs
new file mode 100644
index 000000000..4a3cfd50b
--- /dev/null
+++ b/compiler/rustc_const_eval/src/util/caller_location.rs
@@ -0,0 +1,66 @@
+use rustc_hir::LangItem;
+use rustc_middle::mir;
+use rustc_middle::query::TyCtxtAt;
+use rustc_middle::ty;
+use rustc_middle::ty::layout::LayoutOf;
+use rustc_span::symbol::Symbol;
+use rustc_type_ir::Mutability;
+
+use crate::const_eval::{mk_eval_cx, CanAccessStatics, CompileTimeEvalContext};
+use crate::interpret::*;
+
+/// Allocate a `const core::panic::Location` with the provided filename and line/column numbers.
+fn alloc_caller_location<'mir, 'tcx>(
+    ecx: &mut CompileTimeEvalContext<'mir, 'tcx>,
+    filename: Symbol,
+    line: u32,
+    col: u32,
+) -> MPlaceTy<'tcx> {
+    let loc_details = ecx.tcx.sess.opts.unstable_opts.location_detail;
+    // This can fail if rustc runs out of memory right here. Trying to emit an error would be
+    // pointless, since that would require allocating more memory than these short strings.
+    let file = if loc_details.file {
+        ecx.allocate_str(filename.as_str(), MemoryKind::CallerLocation, Mutability::Not).unwrap()
+    } else {
+        // FIXME: This creates a new allocation each time. It might be preferable to
+        // perform this allocation only once, and re-use the `MPlaceTy`.
+        // See https://github.com/rust-lang/rust/pull/89920#discussion_r730012398
+        ecx.allocate_str("<redacted>", MemoryKind::CallerLocation, Mutability::Not).unwrap()
+    };
+    let line = if loc_details.line { Scalar::from_u32(line) } else { Scalar::from_u32(0) };
+    let col = if loc_details.column { Scalar::from_u32(col) } else { Scalar::from_u32(0) };
+
+    // Allocate memory for `CallerLocation` struct.
+    let loc_ty = ecx
+        .tcx
+        .type_of(ecx.tcx.require_lang_item(LangItem::PanicLocation, None))
+        .instantiate(*ecx.tcx, ecx.tcx.mk_args(&[ecx.tcx.lifetimes.re_erased.into()]));
+    let loc_layout = ecx.layout_of(loc_ty).unwrap();
+    let location = ecx.allocate(loc_layout, MemoryKind::CallerLocation).unwrap();
+
+    // Initialize fields.
+    ecx.write_immediate(file.to_ref(ecx), &ecx.project_field(&location, 0).unwrap())
+        .expect("writing to memory we just allocated cannot fail");
+    ecx.write_scalar(line, &ecx.project_field(&location, 1).unwrap())
+        .expect("writing to memory we just allocated cannot fail");
+    ecx.write_scalar(col, &ecx.project_field(&location, 2).unwrap())
+        .expect("writing to memory we just allocated cannot fail");
+
+    location
+}
+
+pub(crate) fn const_caller_location_provider(
+    tcx: TyCtxtAt<'_>,
+    file: Symbol,
+    line: u32,
+    col: u32,
+) -> mir::ConstValue<'_> {
+    trace!("const_caller_location: {}:{}:{}", file, line, col);
+    let mut ecx = mk_eval_cx(tcx.tcx, tcx.span, ty::ParamEnv::reveal_all(), CanAccessStatics::No);
+
+    let loc_place = alloc_caller_location(&mut ecx, file, line, col);
+    if intern_const_alloc_recursive(&mut ecx, InternKind::Constant, &loc_place).is_err() {
+        bug!("intern_const_alloc_recursive should not error in this case")
+    }
+    mir::ConstValue::Scalar(Scalar::from_maybe_pointer(loc_place.ptr(), &tcx))
+}
diff --git a/compiler/rustc_const_eval/src/util/mod.rs b/compiler/rustc_const_eval/src/util/mod.rs
index 040b3071e..1e58bd645 100644
--- a/compiler/rustc_const_eval/src/util/mod.rs
+++ b/compiler/rustc_const_eval/src/util/mod.rs
@@ -1,6 +1,7 @@
 use rustc_middle::mir;
 
 mod alignment;
+pub(crate) mod caller_location;
 mod check_validity_requirement;
 mod compare_types;
 mod type_name;
diff --git a/compiler/rustc_const_eval/src/util/type_name.rs b/compiler/rustc_const_eval/src/util/type_name.rs
index a924afda6..a82b65b19 100644
--- a/compiler/rustc_const_eval/src/util/type_name.rs
+++ b/compiler/rustc_const_eval/src/util/type_name.rs
@@ -3,7 +3,7 @@ use rustc_hir::def_id::CrateNum;
 use rustc_hir::definitions::DisambiguatedDefPathData;
 use rustc_middle::ty::{
     self,
-    print::{PrettyPrinter, Print, Printer},
+    print::{PrettyPrinter, Print, PrintError, Printer},
     GenericArg, GenericArgKind, Ty, TyCtxt,
 };
 use std::fmt::Write;
@@ -14,23 +14,15 @@ struct AbsolutePathPrinter<'tcx> {
 }
 
 impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
-    type Error = std::fmt::Error;
-
-    type Path = Self;
-    type Region = Self;
-    type Type = Self;
-    type DynExistential = Self;
-    type Const = Self;
-
     fn tcx(&self) -> TyCtxt<'tcx> {
         self.tcx
     }
 
-    fn print_region(self, _region: ty::Region<'_>) -> Result<Self::Region, Self::Error> {
-        Ok(self)
+    fn print_region(&mut self, _region: ty::Region<'_>) -> Result<(), PrintError> {
+        Ok(())
     }
 
-    fn print_type(mut self, ty: Ty<'tcx>) -> Result<Self::Type, Self::Error> {
+    fn print_type(&mut self, ty: Ty<'tcx>) -> Result<(), PrintError> {
         match *ty.kind() {
             // Types without identity.
             ty::Bool
@@ -51,7 +43,7 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
             // Placeholders (all printed as `_` to uniformize them).
             ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error(_) => {
                 write!(self, "_")?;
-                Ok(self)
+                Ok(())
             }
 
             // Types with identity (print the module path).
@@ -59,53 +51,53 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
             | ty::FnDef(def_id, args)
             | ty::Alias(ty::Projection | ty::Opaque, ty::AliasTy { def_id, args, .. })
             | ty::Closure(def_id, args)
-            | ty::Generator(def_id, args, _) => self.print_def_path(def_id, args),
+            | ty::Coroutine(def_id, args, _) => self.print_def_path(def_id, args),
             ty::Foreign(def_id) => self.print_def_path(def_id, &[]),
 
             ty::Alias(ty::Weak, _) => bug!("type_name: unexpected weak projection"),
             ty::Alias(ty::Inherent, _) => bug!("type_name: unexpected inherent projection"),
-            ty::GeneratorWitness(..) => bug!("type_name: unexpected `GeneratorWitness`"),
+            ty::CoroutineWitness(..) => bug!("type_name: unexpected `CoroutineWitness`"),
         }
     }
 
-    fn print_const(self, ct: ty::Const<'tcx>) -> Result<Self::Const, Self::Error> {
+    fn print_const(&mut self, ct: ty::Const<'tcx>) -> Result<(), PrintError> {
         self.pretty_print_const(ct, false)
     }
 
     fn print_dyn_existential(
-        self,
+        &mut self,
         predicates: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
-    ) -> Result<Self::DynExistential, Self::Error> {
+    ) -> Result<(), PrintError> {
         self.pretty_print_dyn_existential(predicates)
     }
 
-    fn path_crate(mut self, cnum: CrateNum) -> Result<Self::Path, Self::Error> {
+    fn path_crate(&mut self, cnum: CrateNum) -> Result<(), PrintError> {
         self.path.push_str(self.tcx.crate_name(cnum).as_str());
-        Ok(self)
+        Ok(())
     }
 
     fn path_qualified(
-        self,
+        &mut self,
         self_ty: Ty<'tcx>,
         trait_ref: Option<ty::TraitRef<'tcx>>,
-    ) -> Result<Self::Path, Self::Error> {
+    ) -> Result<(), PrintError> {
         self.pretty_path_qualified(self_ty, trait_ref)
     }
 
     fn path_append_impl(
-        self,
-        print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
+        &mut self,
+        print_prefix: impl FnOnce(&mut Self) -> Result<(), PrintError>,
         _disambiguated_data: &DisambiguatedDefPathData,
         self_ty: Ty<'tcx>,
         trait_ref: Option<ty::TraitRef<'tcx>>,
-    ) -> Result<Self::Path, Self::Error> {
+    ) -> Result<(), PrintError> {
         self.pretty_path_append_impl(
-            |mut cx| {
-                cx = print_prefix(cx)?;
+            |cx| {
+                print_prefix(cx)?;
 
                 cx.path.push_str("::");
 
-                Ok(cx)
+                Ok(())
             },
             self_ty,
             trait_ref,
@@ -113,29 +105,29 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
     }
 
     fn path_append(
-        mut self,
-        print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
+        &mut self,
+        print_prefix: impl FnOnce(&mut Self) -> Result<(), PrintError>,
         disambiguated_data: &DisambiguatedDefPathData,
-    ) -> Result<Self::Path, Self::Error> {
-        self = print_prefix(self)?;
+    ) -> Result<(), PrintError> {
+        print_prefix(self)?;
 
         write!(self.path, "::{}", disambiguated_data.data).unwrap();
 
-        Ok(self)
+        Ok(())
     }
 
     fn path_generic_args(
-        mut self,
-        print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
+        &mut self,
+        print_prefix: impl FnOnce(&mut Self) -> Result<(), PrintError>,
         args: &[GenericArg<'tcx>],
-    ) -> Result<Self::Path, Self::Error> {
-        self = print_prefix(self)?;
+    ) -> Result<(), PrintError> {
+        print_prefix(self)?;
         let args =
             args.iter().cloned().filter(|arg| !matches!(arg.unpack(), GenericArgKind::Lifetime(_)));
         if args.clone().next().is_some() {
             self.generic_delimiters(|cx| cx.comma_sep(args))
         } else {
-            Ok(self)
+            Ok(())
         }
     }
 }
@@ -144,31 +136,31 @@ impl<'tcx> PrettyPrinter<'tcx> for AbsolutePathPrinter<'tcx> {
     fn should_print_region(&self, _region: ty::Region<'_>) -> bool {
         false
     }
-    fn comma_sep<T>(mut self, mut elems: impl Iterator<Item = T>) -> Result<Self, Self::Error>
+    fn comma_sep<T>(&mut self, mut elems: impl Iterator<Item = T>) -> Result<(), PrintError>
     where
-        T: Print<'tcx, Self, Output = Self, Error = Self::Error>,
+        T: Print<'tcx, Self>,
     {
         if let Some(first) = elems.next() {
-            self = first.print(self)?;
+            first.print(self)?;
             for elem in elems {
                 self.path.push_str(", ");
-                self = elem.print(self)?;
+                elem.print(self)?;
             }
         }
-        Ok(self)
+        Ok(())
     }
 
     fn generic_delimiters(
-        mut self,
-        f: impl FnOnce(Self) -> Result<Self, Self::Error>,
-    ) -> Result<Self, Self::Error> {
+        &mut self,
+        f: impl FnOnce(&mut Self) -> Result<(), PrintError>,
+    ) -> Result<(), PrintError> {
         write!(self, "<")?;
 
-        self = f(self)?;
+        f(self)?;
 
         write!(self, ">")?;
 
-        Ok(self)
+        Ok(())
     }
 
     fn should_print_verbose(&self) -> bool {
@@ -185,5 +177,7 @@ impl Write for AbsolutePathPrinter<'_> {
 }
 
 pub fn type_name<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> String {
-    AbsolutePathPrinter { tcx, path: String::new() }.print_type(ty).unwrap().path
+    let mut printer = AbsolutePathPrinter { tcx, path: String::new() };
+    printer.print_type(ty).unwrap();
+    printer.path
 }