diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src/consts.rs')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/consts.rs | 83 |
1 files changed, 16 insertions, 67 deletions
diff --git a/compiler/rustc_codegen_llvm/src/consts.rs b/compiler/rustc_codegen_llvm/src/consts.rs index b143e28c5f9..33a85adeb87 100644 --- a/compiler/rustc_codegen_llvm/src/consts.rs +++ b/compiler/rustc_codegen_llvm/src/consts.rs @@ -6,8 +6,8 @@ use rustc_hir::def::DefKind; use rustc_hir::def_id::DefId; use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs}; use rustc_middle::mir::interpret::{ - read_target_uint, Allocation, ConstAllocation, ErrorHandled, InitChunk, Pointer, - Scalar as InterpScalar, + Allocation, ConstAllocation, ErrorHandled, InitChunk, Pointer, Scalar as InterpScalar, + read_target_uint, }; use rustc_middle::mir::mono::MonoItem; use rustc_middle::ty::layout::LayoutOf; @@ -73,8 +73,8 @@ pub(crate) fn const_alloc_to_llvm<'ll>( // Generating partially-uninit consts is limited to small numbers of chunks, // to avoid the cost of generating large complex const expressions. - // For example, `[(u32, u8); 1024 * 1024]` contains uninit padding in each element, - // and would result in `{ [5 x i8] zeroinitializer, [3 x i8] undef, ...repeat 1M times... }`. + // For example, `[(u32, u8); 1024 * 1024]` contains uninit padding in each element, and + // would result in `{ [5 x i8] zeroinitializer, [3 x i8] undef, ...repeat 1M times... }`. let max = cx.sess().opts.unstable_opts.uninit_const_chunk_threshold; let allow_uninit_chunks = chunks.clone().take(max.saturating_add(1)).count() <= max; @@ -249,8 +249,8 @@ impl<'ll> CodegenCx<'ll, '_> { trace!(?instance); let DefKind::Static { nested, .. } = self.tcx.def_kind(def_id) else { bug!() }; - // Nested statics do not have a type, so pick a dummy type and let `codegen_static` figure out - // the llvm type from the actual evaluated initializer. + // Nested statics do not have a type, so pick a dummy type and let `codegen_static` figure + // out the llvm type from the actual evaluated initializer. let llty = if nested { self.type_i8() } else { @@ -262,7 +262,7 @@ impl<'ll> CodegenCx<'ll, '_> { } #[instrument(level = "debug", skip(self, llty))] - pub(crate) fn get_static_inner(&self, def_id: DefId, llty: &'ll Type) -> &'ll Value { + fn get_static_inner(&self, def_id: DefId, llty: &'ll Type) -> &'ll Value { let instance = Instance::mono(self.tcx, def_id); if let Some(&g) = self.instances.borrow().get(&instance) { trace!("used cached value"); @@ -320,15 +320,16 @@ impl<'ll> CodegenCx<'ll, '_> { } if !def_id.is_local() { - let needs_dll_storage_attr = self.use_dll_storage_attrs && !self.tcx.is_foreign_item(def_id) && + let needs_dll_storage_attr = self.use_dll_storage_attrs + && !self.tcx.is_foreign_item(def_id) // Local definitions can never be imported, so we must not apply // the DLLImport annotation. - !dso_local && + && !dso_local // ThinLTO can't handle this workaround in all cases, so we don't // emit the attrs. Instead we make them unnecessary by disallowing // dynamic linking when linker plugin based LTO is enabled. - !self.tcx.sess.opts.cg.linker_plugin_lto.enabled() && - self.tcx.sess.lto() != Lto::Thin; + && !self.tcx.sess.opts.cg.linker_plugin_lto.enabled() + && self.tcx.sess.lto() != Lto::Thin; // If this assertion triggers, there's something wrong with commandline // argument validation. @@ -390,7 +391,7 @@ impl<'ll> CodegenCx<'ll, '_> { let val_llty = self.val_ty(v); let g = self.get_static_inner(def_id, val_llty); - let llty = self.val_ty(g); + let llty = llvm::LLVMGlobalGetValueType(g); let g = if val_llty == llty { g @@ -442,58 +443,6 @@ impl<'ll> CodegenCx<'ll, '_> { if attrs.flags.contains(CodegenFnAttrFlags::THREAD_LOCAL) { llvm::set_thread_local_mode(g, self.tls_model); - - // Do not allow LLVM to change the alignment of a TLS on macOS. - // - // By default a global's alignment can be freely increased. - // This allows LLVM to generate more performant instructions - // e.g., using load-aligned into a SIMD register. - // - // However, on macOS 10.10 or below, the dynamic linker does not - // respect any alignment given on the TLS (radar 24221680). - // This will violate the alignment assumption, and causing segfault at runtime. - // - // This bug is very easy to trigger. In `println!` and `panic!`, - // the `LOCAL_STDOUT`/`LOCAL_STDERR` handles are stored in a TLS, - // which the values would be `mem::replace`d on initialization. - // The implementation of `mem::replace` will use SIMD - // whenever the size is 32 bytes or higher. LLVM notices SIMD is used - // and tries to align `LOCAL_STDOUT`/`LOCAL_STDERR` to a 32-byte boundary, - // which macOS's dyld disregarded and causing crashes - // (see issues #51794, #51758, #50867, #48866 and #44056). - // - // To workaround the bug, we trick LLVM into not increasing - // the global's alignment by explicitly assigning a section to it - // (equivalent to automatically generating a `#[link_section]` attribute). - // See the comment in the `GlobalValue::canIncreaseAlignment()` function - // of `lib/IR/Globals.cpp` for why this works. - // - // When the alignment is not increased, the optimized `mem::replace` - // will use load-unaligned instructions instead, and thus avoiding the crash. - // - // We could remove this hack whenever we decide to drop macOS 10.10 support. - if self.tcx.sess.target.is_like_osx { - // The `inspect` method is okay here because we checked for provenance, and - // because we are doing this access to inspect the final interpreter state - // (not as part of the interpreter execution). - // - // FIXME: This check requires that the (arbitrary) value of undefined bytes - // happens to be zero. Instead, we should only check the value of defined bytes - // and set all undefined bytes to zero if this allocation is headed for the - // BSS. - let all_bytes_are_zero = alloc.provenance().ptrs().is_empty() - && alloc - .inspect_with_uninit_and_ptr_outside_interpreter(0..alloc.len()) - .iter() - .all(|&byte| byte == 0); - - let sect_name = if all_bytes_are_zero { - c"__DATA,__thread_bss" - } else { - c"__DATA,__thread_data" - }; - llvm::LLVMSetSection(g, sect_name.as_ptr()); - } } // Wasm statics with custom link sections get special treatment as they @@ -551,8 +500,8 @@ impl<'ll> CodegenCx<'ll, '_> { // `#[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 check happens when assigning the `CodegenFnAttrFlags` in + // `rustc_hir_analysis`, so we don't need to take care of it here. self.add_compiler_used_global(g); } if attrs.flags.contains(CodegenFnAttrFlags::USED_LINKER) { @@ -565,7 +514,7 @@ impl<'ll> CodegenCx<'ll, '_> { } } -impl<'ll> StaticMethods for CodegenCx<'ll, '_> { +impl<'ll> StaticCodegenMethods for CodegenCx<'ll, '_> { fn static_addr_of(&self, cv: &'ll Value, align: Align, kind: Option<&str>) -> &'ll Value { if let Some(&gv) = self.const_globals.borrow().get(&cv) { unsafe { |