diff --git a/Cargo.lock b/Cargo.lock
index a18219b56837e..87a68270e3efb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -195,9 +195,9 @@ dependencies = [
 
 [[package]]
 name = "ar_archive_writer"
-version = "0.4.0"
+version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "de11a9d32db3327f981143bdf699ade4d637c6887b13b97e6e91a9154666963c"
+checksum = "01667f6f40216b9a0b2945e05fed5f1ad0ab6470e69cb9378001e37b1c0668e4"
 dependencies = [
  "object 0.36.3",
 ]
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
index 30f90bada9adc..554a6d26ad901 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
@@ -629,6 +629,9 @@ pub fn file_metadata<'ll>(cx: &CodegenCx<'ll, '_>, source_file: &SourceFile) ->
         };
         let hash_value = hex_encode(source_file.src_hash.hash_bytes());
 
+        let source =
+            cx.sess().opts.unstable_opts.embed_source.then_some(()).and(source_file.src.as_ref());
+
         unsafe {
             llvm::LLVMRustDIBuilderCreateFile(
                 DIB(cx),
@@ -639,6 +642,8 @@ pub fn file_metadata<'ll>(cx: &CodegenCx<'ll, '_>, source_file: &SourceFile) ->
                 hash_kind,
                 hash_value.as_ptr().cast(),
                 hash_value.len(),
+                source.map_or(ptr::null(), |x| x.as_ptr().cast()),
+                source.map_or(0, |x| x.len()),
             )
         }
     }
@@ -659,6 +664,8 @@ pub fn unknown_file_metadata<'ll>(cx: &CodegenCx<'ll, '_>) -> &'ll DIFile {
             llvm::ChecksumKind::None,
             hash_value.as_ptr().cast(),
             hash_value.len(),
+            ptr::null(),
+            0,
         )
     })
 }
@@ -943,6 +950,8 @@ pub fn build_compile_unit_di_node<'ll, 'tcx>(
             llvm::ChecksumKind::None,
             ptr::null(),
             0,
+            ptr::null(),
+            0,
         );
 
         let unit_metadata = llvm::LLVMRustDIBuilderCreateCompileUnit(
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index faabbcb020d5f..7a495174ff1aa 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -1860,6 +1860,8 @@ extern "C" {
         CSKind: ChecksumKind,
         Checksum: *const c_char,
         ChecksumLen: size_t,
+        Source: *const c_char,
+        SourceLen: size_t,
     ) -> &'a DIFile;
 
     pub fn LLVMRustDIBuilderCreateSubroutineType<'a>(
diff --git a/compiler/rustc_codegen_ssa/Cargo.toml b/compiler/rustc_codegen_ssa/Cargo.toml
index e3033b332caee..56b75f9b3292d 100644
--- a/compiler/rustc_codegen_ssa/Cargo.toml
+++ b/compiler/rustc_codegen_ssa/Cargo.toml
@@ -5,7 +5,7 @@ edition = "2021"
 
 [dependencies]
 # tidy-alphabetical-start
-ar_archive_writer = "0.4.0"
+ar_archive_writer = "0.4.2"
 arrayvec = { version = "0.7", default-features = false }
 bitflags = "2.4.1"
 cc = "1.0.90"
diff --git a/compiler/rustc_codegen_ssa/src/back/archive.rs b/compiler/rustc_codegen_ssa/src/back/archive.rs
index 38a440a707a23..c8c1bd3e8f9c3 100644
--- a/compiler/rustc_codegen_ssa/src/back/archive.rs
+++ b/compiler/rustc_codegen_ssa/src/back/archive.rs
@@ -108,7 +108,11 @@ pub trait ArchiveBuilderBuilder {
                 &exports,
                 machine,
                 !sess.target.is_like_msvc,
-                /*comdat=*/ false,
+                // Enable compatibility with MSVC's `/WHOLEARCHIVE` flag.
+                // Without this flag a duplicate symbol error would be emitted
+                // when linking a rust staticlib using `/WHOLEARCHIVE`.
+                // See #129020
+                true,
             ) {
                 sess.dcx()
                     .emit_fatal(ErrorCreatingImportLibrary { lib_name, error: error.to_string() });
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
index 16eeb57b2b967..14c5f8d9f16da 100644
--- a/compiler/rustc_hir_analysis/src/check/check.rs
+++ b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -529,7 +529,7 @@ fn check_opaque_precise_captures<'tcx>(tcx: TyCtxt<'tcx>, opaque_def_id: LocalDe
 
         match tcx.named_bound_var(hir_id) {
             Some(ResolvedArg::EarlyBound(def_id)) => {
-                expected_captures.insert(def_id);
+                expected_captures.insert(def_id.to_def_id());
 
                 // Make sure we allow capturing these lifetimes through `Self` and
                 // `T::Assoc` projection syntax, too. These will occur when we only
@@ -538,7 +538,7 @@ fn check_opaque_precise_captures<'tcx>(tcx: TyCtxt<'tcx>, opaque_def_id: LocalDe
                 // feature -- see <https://github.com/rust-lang/rust/pull/115659>.
                 if let DefKind::LifetimeParam = tcx.def_kind(def_id)
                     && let Some(def_id) = tcx
-                        .map_opaque_lifetime_to_parent_lifetime(def_id.expect_local())
+                        .map_opaque_lifetime_to_parent_lifetime(def_id)
                         .opt_param_def_id(tcx, tcx.parent(opaque_def_id.to_def_id()))
                 {
                     shadowed_captures.insert(def_id);
diff --git a/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs b/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
index ae0c70d232685..0cf9e128bceef 100644
--- a/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
+++ b/compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
@@ -13,7 +13,6 @@ use rustc_ast::visit::walk_list;
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{GenericArg, GenericParam, GenericParamKind, HirId, HirIdMap, LifetimeName, Node};
 use rustc_macros::extension;
@@ -22,7 +21,7 @@ use rustc_middle::middle::resolve_bound_vars::*;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::{self, TyCtxt, TypeSuperVisitable, TypeVisitor};
 use rustc_middle::{bug, span_bug};
-use rustc_span::def_id::DefId;
+use rustc_span::def_id::{DefId, LocalDefId};
 use rustc_span::symbol::{sym, Ident};
 use rustc_span::Span;
 
@@ -32,7 +31,7 @@ use crate::errors;
 impl ResolvedArg {
     fn early(param: &GenericParam<'_>) -> (LocalDefId, ResolvedArg) {
         debug!("ResolvedArg::early: def_id={:?}", param.def_id);
-        (param.def_id, ResolvedArg::EarlyBound(param.def_id.to_def_id()))
+        (param.def_id, ResolvedArg::EarlyBound(param.def_id))
     }
 
     fn late(idx: u32, param: &GenericParam<'_>) -> (LocalDefId, ResolvedArg) {
@@ -41,10 +40,10 @@ impl ResolvedArg {
             "ResolvedArg::late: idx={:?}, param={:?} depth={:?} def_id={:?}",
             idx, param, depth, param.def_id,
         );
-        (param.def_id, ResolvedArg::LateBound(depth, idx, param.def_id.to_def_id()))
+        (param.def_id, ResolvedArg::LateBound(depth, idx, param.def_id))
     }
 
-    fn id(&self) -> Option<DefId> {
+    fn id(&self) -> Option<LocalDefId> {
         match *self {
             ResolvedArg::StaticLifetime | ResolvedArg::Error(_) => None,
 
@@ -288,13 +287,14 @@ fn late_arg_as_bound_arg<'tcx>(
 ) -> ty::BoundVariableKind {
     match arg {
         ResolvedArg::LateBound(_, _, def_id) => {
-            let name = tcx.hir().name(tcx.local_def_id_to_hir_id(def_id.expect_local()));
+            let def_id = def_id.to_def_id();
+            let name = tcx.item_name(def_id);
             match param.kind {
                 GenericParamKind::Lifetime { .. } => {
-                    ty::BoundVariableKind::Region(ty::BrNamed(*def_id, name))
+                    ty::BoundVariableKind::Region(ty::BrNamed(def_id, name))
                 }
                 GenericParamKind::Type { .. } => {
-                    ty::BoundVariableKind::Ty(ty::BoundTyKind::Param(*def_id, name))
+                    ty::BoundVariableKind::Ty(ty::BoundTyKind::Param(def_id, name))
                 }
                 GenericParamKind::Const { .. } => ty::BoundVariableKind::Const,
             }
@@ -717,7 +717,6 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
                     // In the future, this should be fixed and this error should be removed.
                     let def = self.map.defs.get(&lifetime.hir_id).copied();
                     let Some(ResolvedArg::LateBound(_, _, lifetime_def_id)) = def else { continue };
-                    let Some(lifetime_def_id) = lifetime_def_id.as_local() else { continue };
                     let lifetime_hir_id = self.tcx.local_def_id_to_hir_id(lifetime_def_id);
 
                     let bad_place = match self.tcx.hir_node(self.tcx.parent_hir_id(lifetime_hir_id))
@@ -1150,7 +1149,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
                             .param_def_id_to_index(self.tcx, region_def_id.to_def_id())
                             .is_some()
                     {
-                        break Some(ResolvedArg::EarlyBound(region_def_id.to_def_id()));
+                        break Some(ResolvedArg::EarlyBound(region_def_id));
                     }
                     break None;
                 }
@@ -1259,7 +1258,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
                     kind => span_bug!(
                         use_span,
                         "did not expect to resolve lifetime to {}",
-                        kind.descr(param_def_id)
+                        kind.descr(param_def_id.to_def_id())
                     ),
                 };
                 def = ResolvedArg::Error(guar);
@@ -1277,10 +1276,10 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
                         kind: hir::ImplItemKind::Fn(..),
                         ..
                     }) => {
-                        def = ResolvedArg::Free(owner_id.to_def_id(), def.id().unwrap());
+                        def = ResolvedArg::Free(owner_id.def_id, def.id().unwrap());
                     }
                     Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(closure), .. }) => {
-                        def = ResolvedArg::Free(closure.def_id.to_def_id(), def.id().unwrap());
+                        def = ResolvedArg::Free(closure.def_id, def.id().unwrap());
                     }
                     _ => {}
                 }
@@ -1351,7 +1350,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
                             .param_def_id_to_index(self.tcx, param_def_id.to_def_id())
                             .is_some()
                     {
-                        break Some(ResolvedArg::EarlyBound(param_def_id.to_def_id()));
+                        break Some(ResolvedArg::EarlyBound(param_def_id));
                     }
                     break None;
                 }
diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
index 2fb1bcf2dbfff..5c8ecf254a54e 100644
--- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
+++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
@@ -296,25 +296,29 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             Some(rbv::ResolvedArg::StaticLifetime) => tcx.lifetimes.re_static,
 
             Some(rbv::ResolvedArg::LateBound(debruijn, index, def_id)) => {
-                let name = lifetime_name(def_id.expect_local());
+                let name = lifetime_name(def_id);
                 let br = ty::BoundRegion {
                     var: ty::BoundVar::from_u32(index),
-                    kind: ty::BrNamed(def_id, name),
+                    kind: ty::BrNamed(def_id.to_def_id(), name),
                 };
                 ty::Region::new_bound(tcx, debruijn, br)
             }
 
             Some(rbv::ResolvedArg::EarlyBound(def_id)) => {
-                let name = tcx.hir().ty_param_name(def_id.expect_local());
-                let item_def_id = tcx.hir().ty_param_owner(def_id.expect_local());
+                let name = tcx.hir().ty_param_name(def_id);
+                let item_def_id = tcx.hir().ty_param_owner(def_id);
                 let generics = tcx.generics_of(item_def_id);
-                let index = generics.param_def_id_to_index[&def_id];
+                let index = generics.param_def_id_to_index[&def_id.to_def_id()];
                 ty::Region::new_early_param(tcx, ty::EarlyParamRegion { index, name })
             }
 
             Some(rbv::ResolvedArg::Free(scope, id)) => {
-                let name = lifetime_name(id.expect_local());
-                ty::Region::new_late_param(tcx, scope, ty::BrNamed(id, name))
+                let name = lifetime_name(id);
+                ty::Region::new_late_param(
+                    tcx,
+                    scope.to_def_id(),
+                    ty::BrNamed(id.to_def_id(), name),
+                )
 
                 // (*) -- not late-bound, won't change
             }
@@ -1953,15 +1957,14 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         let tcx = self.tcx();
         match tcx.named_bound_var(hir_id) {
             Some(rbv::ResolvedArg::LateBound(debruijn, index, def_id)) => {
-                let name = tcx.item_name(def_id);
+                let name = tcx.item_name(def_id.to_def_id());
                 let br = ty::BoundTy {
                     var: ty::BoundVar::from_u32(index),
-                    kind: ty::BoundTyKind::Param(def_id, name),
+                    kind: ty::BoundTyKind::Param(def_id.to_def_id(), name),
                 };
                 Ty::new_bound(tcx, debruijn, br)
             }
             Some(rbv::ResolvedArg::EarlyBound(def_id)) => {
-                let def_id = def_id.expect_local();
                 let item_def_id = tcx.hir().ty_param_owner(def_id);
                 let generics = tcx.generics_of(item_def_id);
                 let index = generics.param_def_id_to_index[&def_id.to_def_id()];
@@ -1982,10 +1985,10 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             Some(rbv::ResolvedArg::EarlyBound(def_id)) => {
                 // Find the name and index of the const parameter by indexing the generics of
                 // the parent item and construct a `ParamConst`.
-                let item_def_id = tcx.parent(def_id);
+                let item_def_id = tcx.local_parent(def_id);
                 let generics = tcx.generics_of(item_def_id);
-                let index = generics.param_def_id_to_index[&def_id];
-                let name = tcx.item_name(def_id);
+                let index = generics.param_def_id_to_index[&def_id.to_def_id()];
+                let name = tcx.item_name(def_id.to_def_id());
                 ty::Const::new_param(tcx, ty::ParamConst::new(index, name))
             }
             Some(rbv::ResolvedArg::LateBound(debruijn, index, _)) => {
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 34f2dca7c42ff..486136a2bcc10 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -774,6 +774,7 @@ fn test_unstable_options_tracking_hash() {
     tracked!(direct_access_external_data, Some(true));
     tracked!(dual_proc_macros, true);
     tracked!(dwarf_version, Some(5));
+    tracked!(embed_source, true);
     tracked!(emit_thin_lto, false);
     tracked!(export_executable_symbols, true);
     tracked!(fewer_names, Some(true));
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 85132dd4f98f0..d8482567bbe5b 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -1925,8 +1925,8 @@ impl ExplicitOutlivesRequirements {
     fn lifetimes_outliving_lifetime<'tcx>(
         tcx: TyCtxt<'tcx>,
         inferred_outlives: impl Iterator<Item = &'tcx (ty::Clause<'tcx>, Span)>,
-        item: DefId,
-        lifetime: DefId,
+        item: LocalDefId,
+        lifetime: LocalDefId,
     ) -> Vec<ty::Region<'tcx>> {
         let item_generics = tcx.generics_of(item);
 
@@ -1934,7 +1934,7 @@ impl ExplicitOutlivesRequirements {
             .filter_map(|(clause, _)| match clause.kind().skip_binder() {
                 ty::ClauseKind::RegionOutlives(ty::OutlivesPredicate(a, b)) => match *a {
                     ty::ReEarlyParam(ebr)
-                        if item_generics.region_param(ebr, tcx).def_id == lifetime =>
+                        if item_generics.region_param(ebr, tcx).def_id == lifetime.to_def_id() =>
                     {
                         Some(b)
                     }
@@ -1982,7 +1982,7 @@ impl ExplicitOutlivesRequirements {
                 let is_inferred = match tcx.named_bound_var(lifetime.hir_id) {
                     Some(ResolvedArg::EarlyBound(def_id)) => inferred_outlives
                         .iter()
-                        .any(|r| matches!(**r, ty::ReEarlyParam(ebr) if { item_generics.region_param(ebr, tcx).def_id == def_id })),
+                        .any(|r| matches!(**r, ty::ReEarlyParam(ebr) if { item_generics.region_param(ebr, tcx).def_id == def_id.to_def_id() })),
                     _ => false,
                 };
 
@@ -2097,7 +2097,7 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitOutlivesRequirements {
                                         inferred_outlives
                                             .iter()
                                             .filter(|(_, span)| !predicate.span.contains(*span)),
-                                        item.owner_id.to_def_id(),
+                                        item.owner_id.def_id,
                                         region_def_id,
                                     ),
                                     &predicate.bounds,
diff --git a/compiler/rustc_lint/src/impl_trait_overcaptures.rs b/compiler/rustc_lint/src/impl_trait_overcaptures.rs
index 990fb2d16f9dd..2e0da69e92070 100644
--- a/compiler/rustc_lint/src/impl_trait_overcaptures.rs
+++ b/compiler/rustc_lint/src/impl_trait_overcaptures.rs
@@ -300,16 +300,17 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for VisitOpaqueTypes<'tcx> {
                         Some(
                             ResolvedArg::EarlyBound(def_id) | ResolvedArg::LateBound(_, _, def_id),
                         ) => {
-                            if self.tcx.def_kind(self.tcx.parent(def_id)) == DefKind::OpaqueTy {
+                            if self.tcx.def_kind(self.tcx.local_parent(def_id)) == DefKind::OpaqueTy
+                            {
                                 let def_id = self
                                     .tcx
-                                    .map_opaque_lifetime_to_parent_lifetime(def_id.expect_local())
+                                    .map_opaque_lifetime_to_parent_lifetime(def_id)
                                     .opt_param_def_id(self.tcx, self.parent_def_id.to_def_id())
                                     .expect("variable should have been duplicated from parent");
 
                                 explicitly_captured.insert(def_id);
                             } else {
-                                explicitly_captured.insert(def_id);
+                                explicitly_captured.insert(def_id.to_def_id());
                             }
                         }
                         _ => {
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index 79a68b2ff0e67..ed12318c88dae 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -913,14 +913,19 @@ extern "C" LLVMMetadataRef
 LLVMRustDIBuilderCreateFile(LLVMRustDIBuilderRef Builder, const char *Filename,
                             size_t FilenameLen, const char *Directory,
                             size_t DirectoryLen, LLVMRustChecksumKind CSKind,
-                            const char *Checksum, size_t ChecksumLen) {
+                            const char *Checksum, size_t ChecksumLen,
+                            const char *Source, size_t SourceLen) {
 
   std::optional<DIFile::ChecksumKind> llvmCSKind = fromRust(CSKind);
   std::optional<DIFile::ChecksumInfo<StringRef>> CSInfo{};
   if (llvmCSKind)
     CSInfo.emplace(*llvmCSKind, StringRef{Checksum, ChecksumLen});
+  std::optional<StringRef> oSource{};
+  if (Source)
+    oSource = StringRef(Source, SourceLen);
   return wrap(Builder->createFile(StringRef(Filename, FilenameLen),
-                                  StringRef(Directory, DirectoryLen), CSInfo));
+                                  StringRef(Directory, DirectoryLen), CSInfo,
+                                  oSource));
 }
 
 extern "C" LLVMMetadataRef
diff --git a/compiler/rustc_middle/src/middle/resolve_bound_vars.rs b/compiler/rustc_middle/src/middle/resolve_bound_vars.rs
index a4f6d7afe4d11..32e2f3b4b1685 100644
--- a/compiler/rustc_middle/src/middle/resolve_bound_vars.rs
+++ b/compiler/rustc_middle/src/middle/resolve_bound_vars.rs
@@ -2,7 +2,7 @@
 
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_errors::ErrorGuaranteed;
-use rustc_hir::def_id::DefId;
+use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::{ItemLocalId, OwnerId};
 use rustc_macros::{Decodable, Encodable, HashStable, TyDecodable, TyEncodable};
 
@@ -11,9 +11,9 @@ use crate::ty;
 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, Debug, HashStable)]
 pub enum ResolvedArg {
     StaticLifetime,
-    EarlyBound(/* decl */ DefId),
-    LateBound(ty::DebruijnIndex, /* late-bound index */ u32, /* decl */ DefId),
-    Free(DefId, /* lifetime decl */ DefId),
+    EarlyBound(/* decl */ LocalDefId),
+    LateBound(ty::DebruijnIndex, /* late-bound index */ u32, /* decl */ LocalDefId),
+    Free(LocalDefId, /* lifetime decl */ LocalDefId),
     Error(ErrorGuaranteed),
 }
 
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 9b39b84970420..cad3515f06809 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -3035,13 +3035,13 @@ impl<'tcx> TyCtxt<'tcx> {
 
             match self.named_bound_var(lifetime.hir_id) {
                 Some(resolve_bound_vars::ResolvedArg::EarlyBound(ebv)) => {
-                    let new_parent = self.parent(ebv);
+                    let new_parent = self.local_parent(ebv);
 
                     // If we map to another opaque, then it should be a parent
                     // of the opaque we mapped from. Continue mapping.
                     if matches!(self.def_kind(new_parent), DefKind::OpaqueTy) {
-                        debug_assert_eq!(self.parent(parent.to_def_id()), new_parent);
-                        opaque_lifetime_param_def_id = ebv.expect_local();
+                        debug_assert_eq!(self.local_parent(parent), new_parent);
+                        opaque_lifetime_param_def_id = ebv;
                         continue;
                     }
 
@@ -3050,20 +3050,20 @@ impl<'tcx> TyCtxt<'tcx> {
                         self,
                         ty::EarlyParamRegion {
                             index: generics
-                                .param_def_id_to_index(self, ebv)
+                                .param_def_id_to_index(self, ebv.to_def_id())
                                 .expect("early-bound var should be present in fn generics"),
-                            name: self.hir().name(self.local_def_id_to_hir_id(ebv.expect_local())),
+                            name: self.item_name(ebv.to_def_id()),
                         },
                     );
                 }
                 Some(resolve_bound_vars::ResolvedArg::LateBound(_, _, lbv)) => {
-                    let new_parent = self.parent(lbv);
+                    let new_parent = self.local_parent(lbv);
                     return ty::Region::new_late_param(
                         self,
-                        new_parent,
+                        new_parent.to_def_id(),
                         ty::BoundRegionKind::BrNamed(
-                            lbv,
-                            self.hir().name(self.local_def_id_to_hir_id(lbv.expect_local())),
+                            lbv.to_def_id(),
+                            self.item_name(lbv.to_def_id()),
                         ),
                     );
                 }
diff --git a/compiler/rustc_session/messages.ftl b/compiler/rustc_session/messages.ftl
index b84280a3ccf3f..01c371ee49884 100644
--- a/compiler/rustc_session/messages.ftl
+++ b/compiler/rustc_session/messages.ftl
@@ -14,6 +14,10 @@ session_crate_name_empty = crate name must not be empty
 
 session_crate_name_invalid = crate names cannot start with a `-`, but `{$s}` has a leading hyphen
 
+session_embed_source_insufficient_dwarf_version = `-Zembed-source=y` requires at least `-Z dwarf-version=5` but DWARF version is {$dwarf_version}
+
+session_embed_source_requires_debug_info = `-Zembed-source=y` requires debug information to be enabled
+
 session_expr_parentheses_needed = parentheses are required to parse this as an expression
 
 session_failed_to_create_profiler = failed to create profiler: {$err}
diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index 5cc54a5855bbe..15bbd4ff7bf4b 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -165,6 +165,16 @@ pub(crate) struct UnsupportedDwarfVersion {
     pub(crate) dwarf_version: u32,
 }
 
+#[derive(Diagnostic)]
+#[diag(session_embed_source_insufficient_dwarf_version)]
+pub(crate) struct EmbedSourceInsufficientDwarfVersion {
+    pub(crate) dwarf_version: u32,
+}
+
+#[derive(Diagnostic)]
+#[diag(session_embed_source_requires_debug_info)]
+pub(crate) struct EmbedSourceRequiresDebugInfo;
+
 #[derive(Diagnostic)]
 #[diag(session_target_stack_protector_not_supported)]
 pub(crate) struct StackProtectorNotSupportedForTarget<'a> {
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index df72e2430fd50..23231fbffbfdb 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -1701,6 +1701,8 @@ options! {
         them only if an error has not been emitted"),
     ehcont_guard: bool = (false, parse_bool, [TRACKED],
         "generate Windows EHCont Guard tables"),
+    embed_source: bool = (false, parse_bool, [TRACKED],
+        "embed source text in DWARF debug sections (default: no)"),
     emit_stack_sizes: bool = (false, parse_bool, [UNTRACKED],
         "emit a section containing stack size metadata (default: no)"),
     emit_thin_lto: bool = (true, parse_bool, [TRACKED],
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 693867c3853da..68efd0faea5c1 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -37,8 +37,9 @@ use rustc_target::spec::{
 use crate::code_stats::CodeStats;
 pub use crate::code_stats::{DataTypeKind, FieldInfo, FieldKind, SizeKind, VariantInfo};
 use crate::config::{
-    self, CoverageLevel, CrateType, ErrorOutputType, FunctionReturn, Input, InstrumentCoverage,
-    OptLevel, OutFileName, OutputType, RemapPathScopeComponents, SwitchWithOptPath,
+    self, CoverageLevel, CrateType, DebugInfo, ErrorOutputType, FunctionReturn, Input,
+    InstrumentCoverage, OptLevel, OutFileName, OutputType, RemapPathScopeComponents,
+    SwitchWithOptPath,
 };
 use crate::parse::{add_feature_diagnostics, ParseSess};
 use crate::search_paths::{PathKind, SearchPath};
@@ -1306,6 +1307,19 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
             .emit_err(errors::SplitDebugInfoUnstablePlatform { debuginfo: sess.split_debuginfo() });
     }
 
+    if sess.opts.unstable_opts.embed_source {
+        let dwarf_version =
+            sess.opts.unstable_opts.dwarf_version.unwrap_or(sess.target.default_dwarf_version);
+
+        if dwarf_version < 5 {
+            sess.dcx().emit_warn(errors::EmbedSourceInsufficientDwarfVersion { dwarf_version });
+        }
+
+        if sess.opts.debuginfo == DebugInfo::None {
+            sess.dcx().emit_warn(errors::EmbedSourceRequiresDebugInfo);
+        }
+    }
+
     if sess.opts.unstable_opts.instrument_xray.is_some() && !sess.target.options.supports_xray {
         sess.dcx().emit_err(errors::InstrumentationNotSupported { us: "XRay".to_string() });
     }
diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/find_anon_type.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/find_anon_type.rs
index 3f35391be1355..cd61747917a88 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/find_anon_type.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/find_anon_type.rs
@@ -101,7 +101,7 @@ impl<'tcx> Visitor<'tcx> for FindNestedTypeVisitor<'tcx> {
                     // region at the right depth with the same index
                     (Some(rbv::ResolvedArg::EarlyBound(id)), ty::BrNamed(def_id, _)) => {
                         debug!("EarlyBound id={:?} def_id={:?}", id, def_id);
-                        if id == def_id {
+                        if id.to_def_id() == def_id {
                             return ControlFlow::Break(arg);
                         }
                     }
@@ -118,7 +118,7 @@ impl<'tcx> Visitor<'tcx> for FindNestedTypeVisitor<'tcx> {
                             debruijn_index
                         );
                         debug!("LateBound id={:?} def_id={:?}", id, def_id);
-                        if debruijn_index == self.current_index && id == def_id {
+                        if debruijn_index == self.current_index && id.to_def_id() == def_id {
                             return ControlFlow::Break(arg);
                         }
                     }
@@ -192,7 +192,7 @@ impl<'tcx> Visitor<'tcx> for TyPathVisitor<'tcx> {
             // the lifetime of the TyPath!
             (Some(rbv::ResolvedArg::EarlyBound(id)), ty::BrNamed(def_id, _)) => {
                 debug!("EarlyBound id={:?} def_id={:?}", id, def_id);
-                if id == def_id {
+                if id.to_def_id() == def_id {
                     return ControlFlow::Break(());
                 }
             }
@@ -201,7 +201,7 @@ impl<'tcx> Visitor<'tcx> for TyPathVisitor<'tcx> {
                 debug!("FindNestedTypeVisitor::visit_ty: LateBound depth = {:?}", debruijn_index,);
                 debug!("id={:?}", id);
                 debug!("def_id={:?}", def_id);
-                if debruijn_index == self.current_index && id == def_id {
+                if debruijn_index == self.current_index && id.to_def_id() == def_id {
                     return ControlFlow::Break(());
                 }
             }
diff --git a/library/Cargo.lock b/library/Cargo.lock
index 30f5076e1e223..f2f446b61085d 100644
--- a/library/Cargo.lock
+++ b/library/Cargo.lock
@@ -58,9 +58,9 @@ dependencies = [
 
 [[package]]
 name = "compiler_builtins"
-version = "0.1.118"
+version = "0.1.120"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "92afe7344b64cccf3662ca26d5d1c0828ab826f04206b97d856e3625e390e4b5"
+checksum = "38c44e9c76d996d8049dee591a997eab801069ad86ed892ed3039f68b73d301c"
 dependencies = [
  "cc",
  "rustc-std-workspace-core",
diff --git a/library/alloc/Cargo.toml b/library/alloc/Cargo.toml
index bdf16257c7cd0..43799acc02736 100644
--- a/library/alloc/Cargo.toml
+++ b/library/alloc/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2021"
 
 [dependencies]
 core = { path = "../core" }
-compiler_builtins = { version = "0.1.118", features = ['rustc-dep-of-std'] }
+compiler_builtins = { version = "0.1.120", features = ['rustc-dep-of-std'] }
 
 [dev-dependencies]
 rand = { version = "0.8.5", default-features = false, features = ["alloc"] }
diff --git a/library/core/src/num/f16.rs b/library/core/src/num/f16.rs
index 41bd34a270238..bb0cc1c60ba5a 100644
--- a/library/core/src/num/f16.rs
+++ b/library/core/src/num/f16.rs
@@ -261,7 +261,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// let nan = f16::NAN;
     /// let f = 7.0_f16;
@@ -293,7 +293,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// let f = 7.0f16;
     /// let inf = f16::INFINITY;
@@ -319,7 +319,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// let f = 7.0f16;
     /// let inf: f16 = f16::INFINITY;
@@ -347,7 +347,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// let min = f16::MIN_POSITIVE; // 6.1035e-5
     /// let max = f16::MAX;
@@ -377,7 +377,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// let min = f16::MIN_POSITIVE; // 6.1035e-5
     /// let max = f16::MAX;
@@ -409,7 +409,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// use std::num::FpCategory;
     ///
@@ -867,7 +867,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// let value = 4.6_f16;
     /// let rounded = unsafe { value.to_int_unchecked::<u16>() };
@@ -910,7 +910,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// # // FIXME(f16_f128): enable this once const casting works
     /// # // assert_ne!((1f16).to_bits(), 1f16 as u128); // to_bits() is not casting!
@@ -958,7 +958,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// let v = f16::from_bits(0x4a40);
     /// assert_eq!(v, 12.5);
@@ -1071,7 +1071,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// let value = f16::from_be_bytes([0x4a, 0x40]);
     /// assert_eq!(value, 12.5);
@@ -1094,7 +1094,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// let value = f16::from_le_bytes([0x40, 0x4a]);
     /// assert_eq!(value, 12.5);
@@ -1124,7 +1124,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// let value = f16::from_ne_bytes(if cfg!(target_endian = "big") {
     ///     [0x4a, 0x40]
@@ -1257,7 +1257,7 @@ impl f16 {
     ///
     /// ```
     /// #![feature(f16)]
-    /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885
+    /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
     ///
     /// assert!((-3.0f16).clamp(-2.0, 1.0) == -2.0);
     /// assert!((0.0f16).clamp(-2.0, 1.0) == 0.0);
diff --git a/library/std/Cargo.toml b/library/std/Cargo.toml
index 7f23681ee45fc..dca42a3e98ec1 100644
--- a/library/std/Cargo.toml
+++ b/library/std/Cargo.toml
@@ -17,7 +17,7 @@ cfg-if = { version = "1.0", features = ['rustc-dep-of-std'] }
 panic_unwind = { path = "../panic_unwind", optional = true }
 panic_abort = { path = "../panic_abort" }
 core = { path = "../core", public = true }
-compiler_builtins = { version = "0.1.118" }
+compiler_builtins = { version = "0.1.120" }
 profiler_builtins = { path = "../profiler_builtins", optional = true }
 unwind = { path = "../unwind" }
 hashbrown = { version = "0.14", default-features = false, features = [
diff --git a/library/std/build.rs b/library/std/build.rs
index 35a5977b6ebaf..3b77afcc3fc61 100644
--- a/library/std/build.rs
+++ b/library/std/build.rs
@@ -103,9 +103,6 @@ fn main() {
         ("arm64ec", _) => false,
         // MinGW ABI bugs <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115054>
         ("x86_64", "windows") => false,
-        // x86 has ABI bugs that show up with optimizations. This should be partially fixed with
-        // the compiler-builtins update. <https://github.com/rust-lang/rust/issues/123885>
-        ("x86" | "x86_64", _) => false,
         // Missing `__gnu_h2f_ieee` and `__gnu_f2h_ieee`
         ("powerpc" | "powerpc64", _) => false,
         // Missing `__gnu_h2f_ieee` and `__gnu_f2h_ieee`
diff --git a/src/bootstrap/src/core/build_steps/dist.rs b/src/bootstrap/src/core/build_steps/dist.rs
index 8d20b95621384..4957de2e1b791 100644
--- a/src/bootstrap/src/core/build_steps/dist.rs
+++ b/src/bootstrap/src/core/build_steps/dist.rs
@@ -269,34 +269,45 @@ fn make_win_dist(
     let target_libs = find_files(&target_libs, &lib_path);
 
     // Copy runtime dlls next to rustc.exe
-    let dist_bin_dir = rust_root.join("bin/");
-    fs::create_dir_all(&dist_bin_dir).expect("creating dist_bin_dir failed");
-    for src in rustc_dlls {
-        builder.copy_link_to_folder(&src, &dist_bin_dir);
+    let rust_bin_dir = rust_root.join("bin/");
+    fs::create_dir_all(&rust_bin_dir).expect("creating rust_bin_dir failed");
+    for src in &rustc_dlls {
+        builder.copy_link_to_folder(src, &rust_bin_dir);
+    }
+
+    if builder.config.lld_enabled {
+        // rust-lld.exe also needs runtime dlls
+        let rust_target_bin_dir = rust_root.join("lib/rustlib").join(target).join("bin");
+        fs::create_dir_all(&rust_target_bin_dir).expect("creating rust_target_bin_dir failed");
+        for src in &rustc_dlls {
+            builder.copy_link_to_folder(src, &rust_target_bin_dir);
+        }
     }
 
     //Copy platform tools to platform-specific bin directory
-    let target_bin_dir =
-        plat_root.join("lib").join("rustlib").join(target).join("bin").join("self-contained");
-    fs::create_dir_all(&target_bin_dir).expect("creating target_bin_dir failed");
+    let plat_target_bin_self_contained_dir =
+        plat_root.join("lib/rustlib").join(target).join("bin/self-contained");
+    fs::create_dir_all(&plat_target_bin_self_contained_dir)
+        .expect("creating plat_target_bin_self_contained_dir failed");
     for src in target_tools {
-        builder.copy_link_to_folder(&src, &target_bin_dir);
+        builder.copy_link_to_folder(&src, &plat_target_bin_self_contained_dir);
     }
 
     // Warn windows-gnu users that the bundled GCC cannot compile C files
     builder.create(
-        &target_bin_dir.join("GCC-WARNING.txt"),
+        &plat_target_bin_self_contained_dir.join("GCC-WARNING.txt"),
         "gcc.exe contained in this folder cannot be used for compiling C files - it is only \
          used as a linker. In order to be able to compile projects containing C code use \
          the GCC provided by MinGW or Cygwin.",
     );
 
     //Copy platform libs to platform-specific lib directory
-    let target_lib_dir =
-        plat_root.join("lib").join("rustlib").join(target).join("lib").join("self-contained");
-    fs::create_dir_all(&target_lib_dir).expect("creating target_lib_dir failed");
+    let plat_target_lib_self_contained_dir =
+        plat_root.join("lib/rustlib").join(target).join("lib/self-contained");
+    fs::create_dir_all(&plat_target_lib_self_contained_dir)
+        .expect("creating plat_target_lib_self_contained_dir failed");
     for src in target_libs {
-        builder.copy_link_to_folder(&src, &target_lib_dir);
+        builder.copy_link_to_folder(&src, &plat_target_lib_self_contained_dir);
     }
 }
 
diff --git a/src/doc/unstable-book/src/compiler-flags/embed-source.md b/src/doc/unstable-book/src/compiler-flags/embed-source.md
new file mode 100644
index 0000000000000..01a11e3779712
--- /dev/null
+++ b/src/doc/unstable-book/src/compiler-flags/embed-source.md
@@ -0,0 +1,12 @@
+# `embed-source`
+
+This flag controls whether the compiler embeds the program source code text into
+the object debug information section. It takes one of the following values:
+
+* `y`, `yes`, `on` or `true`: put source code in debug info.
+* `n`, `no`, `off`, `false` or no value: omit source code from debug info (the default).
+
+This flag is ignored in configurations that don't emit DWARF debug information
+and is ignored on non-LLVM backends. `-Z embed-source` requires DWARFv5. Use
+`-Z dwarf-version=5` to control the compiler's DWARF target version and `-g` to
+enable debug info generation.
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index db81b4c4282a1..5260e363dd68c 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -272,7 +272,7 @@ fn clean_lifetime<'tcx>(lifetime: &hir::Lifetime, cx: &mut DocContext<'tcx>) ->
         | rbv::ResolvedArg::LateBound(_, _, did)
         | rbv::ResolvedArg::Free(_, did),
     ) = cx.tcx.named_bound_var(lifetime.hir_id)
-        && let Some(lt) = cx.args.get(&did).and_then(|arg| arg.as_lt())
+        && let Some(lt) = cx.args.get(&did.to_def_id()).and_then(|arg| arg.as_lt())
     {
         return lt.clone();
     }
diff --git a/tests/run-make/embed-source-dwarf/main.rs b/tests/run-make/embed-source-dwarf/main.rs
new file mode 100644
index 0000000000000..c80af84f41415
--- /dev/null
+++ b/tests/run-make/embed-source-dwarf/main.rs
@@ -0,0 +1,2 @@
+// hello
+fn main() {}
diff --git a/tests/run-make/embed-source-dwarf/rmake.rs b/tests/run-make/embed-source-dwarf/rmake.rs
new file mode 100644
index 0000000000000..06d550121b0de
--- /dev/null
+++ b/tests/run-make/embed-source-dwarf/rmake.rs
@@ -0,0 +1,70 @@
+//@ ignore-windows
+//@ ignore-apple
+
+// LLVM 17's embed-source implementation requires that source code is attached
+// for all files in the output DWARF debug info. This restriction was lifted in
+// LLVM 18 (87e22bdd2bd6d77d782f9d64b3e3ae5bdcd5080d).
+//@ min-llvm-version: 18
+
+// This test should be replaced with one in tests/debuginfo once we can easily
+// tell via GDB or LLDB if debuginfo contains source code. Cheap tricks in LLDB
+// like setting an invalid source map path don't appear to work, maybe this'll
+// become easier once GDB supports DWARFv6?
+
+use std::collections::HashMap;
+use std::path::PathBuf;
+use std::rc::Rc;
+
+use gimli::{AttributeValue, EndianRcSlice, Reader, RunTimeEndian};
+use object::{Object, ObjectSection};
+use run_make_support::{gimli, object, rfs, rustc};
+
+fn main() {
+    let output = PathBuf::from("embed-source-main");
+    rustc()
+        .input("main.rs")
+        .output(&output)
+        .arg("-g")
+        .arg("-Zembed-source=yes")
+        .arg("-Zdwarf-version=5")
+        .run();
+    let output = rfs::read(output);
+    let obj = object::File::parse(output.as_slice()).unwrap();
+    let endian = if obj.is_little_endian() { RunTimeEndian::Little } else { RunTimeEndian::Big };
+    let dwarf = gimli::Dwarf::load(|section| -> Result<_, ()> {
+        let data = obj.section_by_name(section.name()).map(|s| s.uncompressed_data().unwrap());
+        Ok(EndianRcSlice::new(Rc::from(data.unwrap_or_default().as_ref()), endian))
+    })
+    .unwrap();
+
+    let mut sources = HashMap::new();
+
+    let mut iter = dwarf.units();
+    while let Some(header) = iter.next().unwrap() {
+        let unit = dwarf.unit(header).unwrap();
+        let unit = unit.unit_ref(&dwarf);
+
+        if let Some(program) = &unit.line_program {
+            let header = program.header();
+            for file in header.file_names() {
+                if let Some(source) = file.source() {
+                    let path = unit
+                        .attr_string(file.path_name())
+                        .unwrap()
+                        .to_string_lossy()
+                        .unwrap()
+                        .to_string();
+                    let source =
+                        unit.attr_string(source).unwrap().to_string_lossy().unwrap().to_string();
+                    if !source.is_empty() {
+                        sources.insert(path, source);
+                    }
+                }
+            }
+        }
+    }
+
+    dbg!(&sources);
+    assert_eq!(sources.len(), 1);
+    assert_eq!(sources.get("main.rs").unwrap(), "// hello\nfn main() {}\n");
+}
diff --git a/tests/run-make/msvc-wholearchive/c.c b/tests/run-make/msvc-wholearchive/c.c
new file mode 100644
index 0000000000000..d6847845c6846
--- /dev/null
+++ b/tests/run-make/msvc-wholearchive/c.c
@@ -0,0 +1 @@
+// This page is intentionally left blank
diff --git a/tests/run-make/msvc-wholearchive/dll.def b/tests/run-make/msvc-wholearchive/dll.def
new file mode 100644
index 0000000000000..d55819e0d5e9f
--- /dev/null
+++ b/tests/run-make/msvc-wholearchive/dll.def
@@ -0,0 +1,4 @@
+LIBRARY dll
+EXPORTS
+        hello
+        number
diff --git a/tests/run-make/msvc-wholearchive/rmake.rs b/tests/run-make/msvc-wholearchive/rmake.rs
new file mode 100644
index 0000000000000..98586fd8cc8bd
--- /dev/null
+++ b/tests/run-make/msvc-wholearchive/rmake.rs
@@ -0,0 +1,52 @@
+//! This is a regression test for #129020
+//! It ensures we can use `/WHOLEARCHIVE` to link a rust staticlib into DLL
+//! using the MSVC linker
+
+//@ only-msvc
+// Reason: this is testing the MSVC linker
+
+use std::path::PathBuf;
+
+use run_make_support::{cc, cmd, env_var, extra_c_flags, rustc};
+
+fn main() {
+    // Build the staticlib
+    rustc().crate_type("staticlib").input("static.rs").output("static.lib").run();
+    // Build an empty object to pass to the linker.
+    cc().input("c.c").output("c.obj").args(["-c"]).run();
+
+    // Find the C toolchain's linker.
+    let mut linker = PathBuf::from(env_var("CC"));
+    let linker_flavour = if linker.file_stem().is_some_and(|s| s == "cl") {
+        linker.set_file_name("link.exe");
+        "msvc"
+    } else if linker.file_stem().is_some_and(|s| s == "clang-cl") {
+        linker.set_file_name("lld-link.exe");
+        "llvm"
+    } else {
+        panic!("unknown C toolchain");
+    };
+
+    // As a sanity check, make sure this works without /WHOLEARCHIVE.
+    // Otherwise the actual test failure may be caused by something else.
+    cmd(&linker)
+        .args(["c.obj", "./static.lib", "-dll", "-def:dll.def", "-out:dll.dll"])
+        .args(extra_c_flags())
+        .run();
+
+    // FIXME(@ChrisDenton): this doesn't currently work with llvm's lld-link for other reasons.
+    // May need LLVM patches.
+    if linker_flavour == "msvc" {
+        // Link in the staticlib using `/WHOLEARCHIVE` and produce a DLL.
+        cmd(&linker)
+            .args([
+                "c.obj",
+                "-WHOLEARCHIVE:./static.lib",
+                "-dll",
+                "-def:dll.def",
+                "-out:dll_whole_archive.dll",
+            ])
+            .args(extra_c_flags())
+            .run();
+    }
+}
diff --git a/tests/run-make/msvc-wholearchive/static.rs b/tests/run-make/msvc-wholearchive/static.rs
new file mode 100644
index 0000000000000..881c88565737a
--- /dev/null
+++ b/tests/run-make/msvc-wholearchive/static.rs
@@ -0,0 +1,9 @@
+#[no_mangle]
+pub extern "C" fn hello() {
+    println!("Hello world!");
+}
+
+#[no_mangle]
+pub extern "C" fn number() -> u32 {
+    42
+}
diff --git a/tests/ui/consts/const-float-bits-conv.rs b/tests/ui/consts/const-float-bits-conv.rs
index 45e8ea570ed73..3a526c54dc376 100644
--- a/tests/ui/consts/const-float-bits-conv.rs
+++ b/tests/ui/consts/const-float-bits-conv.rs
@@ -3,8 +3,9 @@
 
 #![feature(const_float_bits_conv)]
 #![feature(const_float_classify)]
+#![feature(f16)]
+#![feature(f128)]
 #![allow(unused_macro_rules)]
-
 // Don't promote
 const fn nop<T>(x: T) -> T { x }
 
@@ -28,6 +29,37 @@ fn has_broken_floats() -> bool {
     std::env::var("TARGET").is_ok_and(|v| v.contains("i586"))
 }
 
+#[cfg(target_arch = "x86_64")]
+fn f16(){
+    const_assert!((1f16).to_bits(), 0x3c00);
+    const_assert!(u16::from_be_bytes(1f16.to_be_bytes()), 0x3c00);
+    const_assert!((12.5f16).to_bits(), 0x4a40);
+    const_assert!(u16::from_le_bytes(12.5f16.to_le_bytes()), 0x4a40);
+    const_assert!((1337f16).to_bits(), 0x6539);
+    const_assert!(u16::from_ne_bytes(1337f16.to_ne_bytes()), 0x6539);
+    const_assert!((-14.25f16).to_bits(), 0xcb20);
+    const_assert!(f16::from_bits(0x3c00), 1.0);
+    const_assert!(f16::from_be_bytes(0x3c00u16.to_be_bytes()), 1.0);
+    const_assert!(f16::from_bits(0x4a40), 12.5);
+    const_assert!(f16::from_le_bytes(0x4a40u16.to_le_bytes()), 12.5);
+    const_assert!(f16::from_bits(0x5be0), 252.0);
+    const_assert!(f16::from_ne_bytes(0x5be0u16.to_ne_bytes()), 252.0);
+    const_assert!(f16::from_bits(0xcb20), -14.25);
+
+    // Check that NaNs roundtrip their bits regardless of signalingness
+    // 0xA is 0b1010; 0x5 is 0b0101 -- so these two together clobbers all the mantissa bits
+    // NOTE: These names assume `f{BITS}::NAN` is a quiet NAN and IEEE754-2008's NaN rules apply!
+    const QUIET_NAN: u16 = f16::NAN.to_bits() ^ 0x0155;
+    const SIGNALING_NAN: u16 = f16::NAN.to_bits() ^ 0x02AA;
+
+    const_assert!(f16::from_bits(QUIET_NAN).is_nan());
+    const_assert!(f16::from_bits(SIGNALING_NAN).is_nan());
+    const_assert!(f16::from_bits(QUIET_NAN).to_bits(), QUIET_NAN);
+    if !has_broken_floats() {
+        const_assert!(f16::from_bits(SIGNALING_NAN).to_bits(), SIGNALING_NAN);
+    }
+}
+
 fn f32() {
     const_assert!((1f32).to_bits(), 0x3f800000);
     const_assert!(u32::from_be_bytes(1f32.to_be_bytes()), 0x3f800000);
@@ -88,7 +120,43 @@ fn f64() {
     }
 }
 
+#[cfg(target_arch = "x86_64")]
+fn f128() {
+    const_assert!((1f128).to_bits(), 0x3fff0000000000000000000000000000);
+    const_assert!(u128::from_be_bytes(1f128.to_be_bytes()), 0x3fff0000000000000000000000000000);
+    const_assert!((12.5f128).to_bits(), 0x40029000000000000000000000000000);
+    const_assert!(u128::from_le_bytes(12.5f128.to_le_bytes()), 0x40029000000000000000000000000000);
+    const_assert!((1337f128).to_bits(), 0x40094e40000000000000000000000000);
+    const_assert!(u128::from_ne_bytes(1337f128.to_ne_bytes()), 0x40094e40000000000000000000000000);
+    const_assert!((-14.25f128).to_bits(), 0xc002c800000000000000000000000000);
+    const_assert!(f128::from_bits(0x3fff0000000000000000000000000000), 1.0);
+    const_assert!(f128::from_be_bytes(0x3fff0000000000000000000000000000u128.to_be_bytes()), 1.0);
+    const_assert!(f128::from_bits(0x40029000000000000000000000000000), 12.5);
+    const_assert!(f128::from_le_bytes(0x40029000000000000000000000000000u128.to_le_bytes()), 12.5);
+    const_assert!(f128::from_bits(0x40094e40000000000000000000000000), 1337.0);
+    assert_eq!(f128::from_ne_bytes(0x40094e40000000000000000000000000u128.to_ne_bytes()), 1337.0);
+    const_assert!(f128::from_bits(0xc002c800000000000000000000000000), -14.25);
+
+    // Check that NaNs roundtrip their bits regardless of signalingness
+    // 0xA is 0b1010; 0x5 is 0b0101 -- so these two together clobbers all the mantissa bits
+    // NOTE: These names assume `f{BITS}::NAN` is a quiet NAN and IEEE754-2008's NaN rules apply!
+    const QUIET_NAN: u128 = f128::NAN.to_bits() | 0x0000_AAAA_AAAA_AAAA_AAAA_AAAA_AAAA_AAAA;
+    const SIGNALING_NAN: u128 = f128::NAN.to_bits() ^ 0x0000_5555_5555_5555_5555_5555_5555_5555;
+
+    const_assert!(f128::from_bits(QUIET_NAN).is_nan());
+    const_assert!(f128::from_bits(SIGNALING_NAN).is_nan());
+    const_assert!(f128::from_bits(QUIET_NAN).to_bits(), QUIET_NAN);
+    if !has_broken_floats() {
+        const_assert!(f128::from_bits(SIGNALING_NAN).to_bits(), SIGNALING_NAN);
+    }
+}
+
 fn main() {
+    #[cfg(target_arch = "x86_64")]
+    {
+        f16();
+        f128();
+    }
     f32();
     f64();
 }