From 888efe74a3b1f54fcb34e5c8c4f17dd2a381989f Mon Sep 17 00:00:00 2001 From: Jubilee Young Date: Fri, 18 Oct 2024 00:00:23 -0700 Subject: [PATCH 1/3] cg_llvm: Switch `llvm::add_global` to `&CStr` --- .../rustc_codegen_llvm/src/coverageinfo/mapgen.rs | 2 +- compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs | 12 +++++++----- compiler/rustc_codegen_llvm/src/llvm/mod.rs | 3 +-- 3 files changed, 9 insertions(+), 8 deletions(-) diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs index c2c261da79b..4075849323a 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs @@ -132,7 +132,7 @@ pub(crate) fn finalize(cx: &CodegenCx<'_, '_>) { .collect::>(); let initializer = cx.const_array(cx.type_ptr(), &name_globals); - let array = llvm::add_global(cx.llmod, cx.val_ty(initializer), "__llvm_coverage_names"); + let array = llvm::add_global(cx.llmod, cx.val_ty(initializer), c"__llvm_coverage_names"); llvm::set_global_constant(array, true); llvm::set_linkage(array, llvm::Linkage::InternalLinkage); llvm::set_initializer(array, initializer); diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs index d7d29eebf85..4192dc39de0 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs @@ -1,4 +1,5 @@ use std::cell::RefCell; +use std::ffi::CString; use libc::c_uint; use rustc_codegen_ssa::traits::{ @@ -284,10 +285,10 @@ pub(crate) fn save_cov_data_to_mod<'ll, 'tcx>( cx: &CodegenCx<'ll, 'tcx>, cov_data_val: &'ll llvm::Value, ) { - let covmap_var_name = llvm::build_string(|s| unsafe { + let covmap_var_name = CString::new(llvm::build_byte_buffer(|s| unsafe { llvm::LLVMRustCoverageWriteMappingVarNameToString(s); - }) - .expect("Rust Coverage Mapping var name failed UTF-8 conversion"); + })) + .unwrap(); debug!("covmap var name: {:?}", covmap_var_name); let covmap_section_name = llvm::build_string(|s| unsafe { @@ -322,7 +323,8 @@ pub(crate) fn save_func_record_to_mod<'ll, 'tcx>( // of descriptions play distinct roles in LLVM IR; therefore, assign them different names (by // appending "u" to the end of the function record var name, to prevent `linkonce_odr` merging. let func_record_var_name = - format!("__covrec_{:X}{}", func_name_hash, if is_used { "u" } else { "" }); + CString::new(format!("__covrec_{:X}{}", func_name_hash, if is_used { "u" } else { "" })) + .unwrap(); debug!("function record var name: {:?}", func_record_var_name); debug!("function record section name: {:?}", covfun_section_name); @@ -334,7 +336,7 @@ pub(crate) fn save_func_record_to_mod<'ll, 'tcx>( llvm::set_section(llglobal, covfun_section_name); // LLVM's coverage mapping format specifies 8-byte alignment for items in this section. llvm::set_alignment(llglobal, Align::EIGHT); - llvm::set_comdat(cx.llmod, llglobal, &func_record_var_name); + llvm::set_comdat(cx.llmod, llglobal, func_record_var_name.to_str().unwrap()); cx.add_used_global(llglobal); } diff --git a/compiler/rustc_codegen_llvm/src/llvm/mod.rs b/compiler/rustc_codegen_llvm/src/llvm/mod.rs index d0db350a149..e790c6696fa 100644 --- a/compiler/rustc_codegen_llvm/src/llvm/mod.rs +++ b/compiler/rustc_codegen_llvm/src/llvm/mod.rs @@ -217,8 +217,7 @@ pub fn set_section(llglobal: &Value, section_name: &str) { } } -pub fn add_global<'a>(llmod: &'a Module, ty: &'a Type, name: &str) -> &'a Value { - let name_cstr = CString::new(name).expect("unexpected CString error"); +pub fn add_global<'a>(llmod: &'a Module, ty: &'a Type, name_cstr: &CStr) -> &'a Value { unsafe { LLVMAddGlobal(llmod, ty, name_cstr.as_ptr()) } } From 45d61b0d2654373405e2a8d44289e883847873e4 Mon Sep 17 00:00:00 2001 From: Jubilee Young Date: Fri, 18 Oct 2024 00:31:28 -0700 Subject: [PATCH 2/3] cg_llvm: Reuse LLVM-C Comdat support Migrate `llvm::set_comdat` and `llvm::SetUniqueComdat` to LLVM-C FFI. Note, now we can call `llvm::set_comdat` only when the target actually supports adding comdat. As this has no convenient LLVM-C API, we implement this as `TargetOptions::supports_comdat`. Co-authored-by: Stuart Cook --- .../rustc_codegen_llvm/src/coverageinfo/mod.rs | 5 ++++- compiler/rustc_codegen_llvm/src/intrinsic.rs | 4 +++- compiler/rustc_codegen_llvm/src/llvm/ffi.rs | 5 ++++- compiler/rustc_codegen_llvm/src/llvm/mod.rs | 17 +++++++++++------ compiler/rustc_codegen_llvm/src/mono_item.rs | 4 +++- compiler/rustc_target/src/spec/mod.rs | 7 +++++++ 6 files changed, 32 insertions(+), 10 deletions(-) diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs index 4192dc39de0..4f93e6ab1e5 100644 --- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs +++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs @@ -13,6 +13,7 @@ use rustc_middle::ty::Instance; use rustc_middle::ty::layout::HasTyCtxt; use rustc_target::abi::{Align, Size}; +use rustc_target::spec::HasTargetSpec; use tracing::{debug, instrument}; use crate::builder::Builder; @@ -336,7 +337,9 @@ pub(crate) fn save_func_record_to_mod<'ll, 'tcx>( llvm::set_section(llglobal, covfun_section_name); // LLVM's coverage mapping format specifies 8-byte alignment for items in this section. llvm::set_alignment(llglobal, Align::EIGHT); - llvm::set_comdat(cx.llmod, llglobal, func_record_var_name.to_str().unwrap()); + if cx.target_spec().supports_comdat() { + llvm::set_comdat(cx.llmod, llglobal, &func_record_var_name); + } cx.add_used_global(llglobal); } diff --git a/compiler/rustc_codegen_llvm/src/intrinsic.rs b/compiler/rustc_codegen_llvm/src/intrinsic.rs index bfe623e7fc3..64f1d21b438 100644 --- a/compiler/rustc_codegen_llvm/src/intrinsic.rs +++ b/compiler/rustc_codegen_llvm/src/intrinsic.rs @@ -787,7 +787,9 @@ fn codegen_msvc_try<'ll>( let tydesc = bx.declare_global("__rust_panic_type_info", bx.val_ty(type_info)); unsafe { llvm::LLVMRustSetLinkage(tydesc, llvm::Linkage::LinkOnceODRLinkage); - llvm::SetUniqueComdat(bx.llmod, tydesc); + if bx.cx.tcx.sess.target.supports_comdat() { + llvm::SetUniqueComdat(bx.llmod, tydesc); + } llvm::LLVMSetInitializer(tydesc, type_info); } diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs index 661debbb9f1..d0034de06c7 100644 --- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs +++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs @@ -646,6 +646,7 @@ struct InvariantOpaque<'a> { pub type Attribute; pub type Metadata; pub type BasicBlock; + pub type Comdat; } #[repr(C)] pub struct Builder<'a>(InvariantOpaque<'a>); @@ -1490,6 +1491,9 @@ pub fn LLVMStructSetBody<'a>( pub fn LLVMSetUnnamedAddress(Global: &Value, UnnamedAddr: UnnamedAddr); pub fn LLVMIsAConstantInt(value_ref: &Value) -> Option<&ConstantInt>; + + pub fn LLVMGetOrInsertComdat(M: &Module, Name: *const c_char) -> &Comdat; + pub fn LLVMSetComdat(V: &Value, C: &Comdat); } #[link(name = "llvm-wrapper", kind = "static")] @@ -2320,7 +2324,6 @@ pub fn LLVMRustBuildOperandBundleDef( pub fn LLVMRustPositionBuilderAtStart<'a>(B: &Builder<'a>, BB: &'a BasicBlock); - pub fn LLVMRustSetComdat<'a>(M: &'a Module, V: &'a Value, Name: *const c_char, NameLen: size_t); pub fn LLVMRustSetModulePICLevel(M: &Module); pub fn LLVMRustSetModulePIELevel(M: &Module); pub fn LLVMRustSetModuleCodeModel(M: &Module, Model: CodeModel); diff --git a/compiler/rustc_codegen_llvm/src/llvm/mod.rs b/compiler/rustc_codegen_llvm/src/llvm/mod.rs index e790c6696fa..b306396e15a 100644 --- a/compiler/rustc_codegen_llvm/src/llvm/mod.rs +++ b/compiler/rustc_codegen_llvm/src/llvm/mod.rs @@ -178,10 +178,10 @@ pub fn SetFunctionCallConv(fn_: &Value, cc: CallConv) { // function. // For more details on COMDAT sections see e.g., https://www.airs.com/blog/archives/52 pub fn SetUniqueComdat(llmod: &Module, val: &Value) { - unsafe { - let name = get_value_name(val); - LLVMRustSetComdat(llmod, val, name.as_ptr().cast(), name.len()); - } + let name_buf = get_value_name(val).to_vec(); + let name = + CString::from_vec_with_nul(name_buf).or_else(|buf| CString::new(buf.into_bytes())).unwrap(); + set_comdat(llmod, val, &name); } pub fn SetUnnamedAddress(global: &Value, unnamed: UnnamedAddr) { @@ -251,9 +251,14 @@ pub fn set_alignment(llglobal: &Value, align: Align) { } } -pub fn set_comdat(llmod: &Module, llglobal: &Value, name: &str) { +/// Get the `name`d comdat from `llmod` and assign it to `llglobal`. +/// +/// Inserts the comdat into `llmod` if it does not exist. +/// It is an error to call this if the target does not support comdat. +pub fn set_comdat(llmod: &Module, llglobal: &Value, name: &CStr) { unsafe { - LLVMRustSetComdat(llmod, llglobal, name.as_ptr().cast(), name.len()); + let comdat = LLVMGetOrInsertComdat(llmod, name.as_ptr()); + LLVMSetComdat(llglobal, comdat); } } diff --git a/compiler/rustc_codegen_llvm/src/mono_item.rs b/compiler/rustc_codegen_llvm/src/mono_item.rs index 02e1995620b..bf6ef219873 100644 --- a/compiler/rustc_codegen_llvm/src/mono_item.rs +++ b/compiler/rustc_codegen_llvm/src/mono_item.rs @@ -64,7 +64,9 @@ fn predefine_fn( unsafe { llvm::LLVMRustSetLinkage(lldecl, base::linkage_to_llvm(linkage)) }; let attrs = self.tcx.codegen_fn_attrs(instance.def_id()); base::set_link_section(lldecl, attrs); - if linkage == Linkage::LinkOnceODR || linkage == Linkage::WeakODR { + if (linkage == Linkage::LinkOnceODR || linkage == Linkage::WeakODR) + && self.tcx.sess.target.supports_comdat() + { llvm::SetUniqueComdat(self.llmod, lldecl); } diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs index 82e11a3afce..f4b45a08195 100644 --- a/compiler/rustc_target/src/spec/mod.rs +++ b/compiler/rustc_target/src/spec/mod.rs @@ -2514,6 +2514,13 @@ fn add_link_args(link_args: &mut LinkArgs, flavor: LinkerFlavor, args: &[&'stati add_link_args_iter(link_args, flavor, args.iter().copied().map(Cow::Borrowed)) } +impl TargetOptions { + pub fn supports_comdat(&self) -> bool { + // XCOFF and MachO don't support COMDAT. + !self.is_like_aix && !self.is_like_osx + } +} + impl TargetOptions { fn link_args(flavor: LinkerFlavor, args: &[&'static str]) -> LinkArgs { let mut link_args = LinkArgs::new(); From 492760020e69f7d92867bf4fba418127d48464d3 Mon Sep 17 00:00:00 2001 From: Jubilee Young Date: Fri, 18 Oct 2024 01:09:21 -0700 Subject: [PATCH 3/3] llvm: Delete LLVMRustSetComdat --- compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp index 72b03fa0560..910c27da954 100644 --- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp +++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp @@ -1658,16 +1658,6 @@ extern "C" void LLVMRustPositionBuilderAtStart(LLVMBuilderRef B, unwrap(B)->SetInsertPoint(unwrap(BB), Point); } -extern "C" void LLVMRustSetComdat(LLVMModuleRef M, LLVMValueRef V, - const char *Name, size_t NameLen) { - Triple TargetTriple = Triple(unwrap(M)->getTargetTriple()); - GlobalObject *GV = unwrap(V); - if (TargetTriple.supportsCOMDAT()) { - StringRef NameRef(Name, NameLen); - GV->setComdat(unwrap(M)->getOrInsertComdat(NameRef)); - } -} - enum class LLVMRustLinkage { ExternalLinkage = 0, AvailableExternallyLinkage = 1,