diff options
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/consts.rs | 12 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/back/link.rs | 5 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/codegen_attrs.rs | 33 |
3 files changed, 13 insertions, 37 deletions
diff --git a/compiler/rustc_codegen_llvm/src/consts.rs b/compiler/rustc_codegen_llvm/src/consts.rs index 4234352c93a..73def2711dc 100644 --- a/compiler/rustc_codegen_llvm/src/consts.rs +++ b/compiler/rustc_codegen_llvm/src/consts.rs @@ -541,12 +541,12 @@ impl<'ll> CodegenCx<'ll, '_> { // in the handling of `.init_array` (the static constructor list) in versions of // the gold linker (prior to the one released with binutils 2.36). // - // That said, we only ever emit these when compiling for ELF targets, unless - // `#[used(compiler)]` is explicitly requested. This is to avoid similar breakage - // on other targets, in particular MachO targets have *their* static constructor - // lists broken if `llvm.compiler.used` is emitted rather than `llvm.used`. However, - // that check happens when assigning the `CodegenFnAttrFlags` in - // `rustc_hir_analysis`, so we don't need to take care of it here. + // That said, we only ever emit these when `#[used(compiler)]` is explicitly + // requested. This is to avoid similar breakage on other targets, in particular + // MachO targets have *their* static constructor lists broken if `llvm.compiler.used` + // is emitted rather than `llvm.used`. However, that check happens when assigning + // the `CodegenFnAttrFlags` in the `codegen_fn_attrs` query, so we don't need to + // take care of it here. self.add_compiler_used_global(g); } if attrs.flags.contains(CodegenFnAttrFlags::USED_LINKER) { diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs index 1a39a0c3fda..168077260a6 100644 --- a/compiler/rustc_codegen_ssa/src/back/link.rs +++ b/compiler/rustc_codegen_ssa/src/back/link.rs @@ -1961,7 +1961,7 @@ fn add_post_link_args(cmd: &mut dyn Linker, sess: &Session, flavor: LinkerFlavor /// This method creates a synthetic object file, which contains undefined references to all symbols /// that are necessary for the linking. They are only present in symbol table but not actually /// used in any sections, so the linker will therefore pick relevant rlibs for linking, but -/// unused `#[no_mangle]` or `#[used]` can still be discard by GC sections. +/// unused `#[no_mangle]` or `#[used(compiler)]` can still be discard by GC sections. /// /// There's a few internal crates in the standard library (aka libcore and /// libstd) which actually have a circular dependence upon one another. This @@ -1995,7 +1995,8 @@ fn add_linked_symbol_object( if file.format() == object::BinaryFormat::MachO { // Divide up the sections into sub-sections via symbols for dead code stripping. - // Without this flag, unused `#[no_mangle]` or `#[used]` cannot be discard on MachO targets. + // Without this flag, unused `#[no_mangle]` or `#[used(compiler)]` cannot be + // discard on MachO targets. file.set_subsections_via_symbols(); } diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs index 4bcafa3be36..0b31fa8fa88 100644 --- a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs +++ b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs @@ -195,35 +195,10 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs { tcx.dcx().emit_err(errors::ExpectedUsedSymbol { span: attr.span() }); } None => { - // Unfortunately, unconditionally using `llvm.used` causes - // issues in handling `.init_array` with the gold linker, - // but using `llvm.compiler.used` caused a nontrivial amount - // of unintentional ecosystem breakage -- particularly on - // Mach-O targets. - // - // As a result, we emit `llvm.compiler.used` only on ELF - // targets. This is somewhat ad-hoc, but actually follows - // our pre-LLVM 13 behavior (prior to the ecosystem - // breakage), and seems to match `clang`'s behavior as well - // (both before and after LLVM 13), possibly because they - // have similar compatibility concerns to us. See - // https://github.com/rust-lang/rust/issues/47384#issuecomment-1019080146 - // and following comments for some discussion of this, as - // well as the comments in `rustc_codegen_llvm` where these - // flags are handled. - // - // Anyway, to be clear: this is still up in the air - // somewhat, and is subject to change in the future (which - // is a good thing, because this would ideally be a bit - // more firmed up). - let is_like_elf = !(tcx.sess.target.is_like_darwin - || tcx.sess.target.is_like_windows - || tcx.sess.target.is_like_wasm); - codegen_fn_attrs.flags |= if is_like_elf { - CodegenFnAttrFlags::USED_COMPILER - } else { - CodegenFnAttrFlags::USED_LINKER - }; + // Unconditionally using `llvm.used` causes issues in handling + // `.init_array` with the gold linker. Luckily gold has been + // deprecated with GCC 15 and rustc now warns about using gold. + codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED_LINKER } } } |