Author: erichkeane Date: Thu Apr 19 07:27:05 2018 New Revision: 330331 URL: http://llvm.org/viewvc/llvm-project?rev=330331&view=rev Log: Fix __attribute__((force_align_arg_pointer)) misalignment bug
The force_align_arg_pointer attribute was using a hardcoded 16-byte alignment value which in combination with -mstack-alignment=32 (or larger) would produce a misaligned stack which could result in crashes when accessing stack buffers using aligned AVX load/store instructions. Fix the issue by using the "stackrealign" function attribute instead of using a hardcoded 16-byte alignment. Patch By: Gramner Differential Revision: https://reviews.llvm.org/D45812 Modified: cfe/trunk/lib/CodeGen/TargetInfo.cpp cfe/trunk/test/CodeGen/function-attributes.c Modified: cfe/trunk/lib/CodeGen/TargetInfo.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/TargetInfo.cpp?rev=330331&r1=330330&r2=330331&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/TargetInfo.cpp (original) +++ cfe/trunk/lib/CodeGen/TargetInfo.cpp Thu Apr 19 07:27:05 2018 @@ -1941,13 +1941,8 @@ void X86_32TargetCodeGenInfo::setTargetA return; if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) { if (FD->hasAttr<X86ForceAlignArgPointerAttr>()) { - // Get the LLVM function. llvm::Function *Fn = cast<llvm::Function>(GV); - - // Now add the 'alignstack' attribute with a value of 16. - llvm::AttrBuilder B; - B.addStackAlignmentAttr(16); - Fn->addAttributes(llvm::AttributeList::FunctionIndex, B); + Fn->addFnAttr("stackrealign"); } if (FD->hasAttr<AnyX86InterruptAttr>()) { llvm::Function *Fn = cast<llvm::Function>(GV); @@ -2299,13 +2294,8 @@ public: return; if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) { if (FD->hasAttr<X86ForceAlignArgPointerAttr>()) { - // Get the LLVM function. - auto *Fn = cast<llvm::Function>(GV); - - // Now add the 'alignstack' attribute with a value of 16. - llvm::AttrBuilder B; - B.addStackAlignmentAttr(16); - Fn->addAttributes(llvm::AttributeList::FunctionIndex, B); + llvm::Function *Fn = cast<llvm::Function>(GV); + Fn->addFnAttr("stackrealign"); } if (FD->hasAttr<AnyX86InterruptAttr>()) { llvm::Function *Fn = cast<llvm::Function>(GV); @@ -2431,13 +2421,8 @@ void WinX86_64TargetCodeGenInfo::setTarg return; if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D)) { if (FD->hasAttr<X86ForceAlignArgPointerAttr>()) { - // Get the LLVM function. - auto *Fn = cast<llvm::Function>(GV); - - // Now add the 'alignstack' attribute with a value of 16. - llvm::AttrBuilder B; - B.addStackAlignmentAttr(16); - Fn->addAttributes(llvm::AttributeList::FunctionIndex, B); + llvm::Function *Fn = cast<llvm::Function>(GV); + Fn->addFnAttr("stackrealign"); } if (FD->hasAttr<AnyX86InterruptAttr>()) { llvm::Function *Fn = cast<llvm::Function>(GV); Modified: cfe/trunk/test/CodeGen/function-attributes.c URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/function-attributes.c?rev=330331&r1=330330&r2=330331&view=diff ============================================================================== --- cfe/trunk/test/CodeGen/function-attributes.c (original) +++ cfe/trunk/test/CodeGen/function-attributes.c Thu Apr 19 07:27:05 2018 @@ -71,7 +71,7 @@ void f15(void) { // PR5254 // CHECK-LABEL: define void @f16 -// CHECK: [[ALIGN:#[0-9]+]] +// CHECK: [[SR:#[0-9]+]] // CHECK: { void __attribute__((force_align_arg_pointer)) f16(void) { } @@ -112,7 +112,7 @@ void f20(void) { // CHECK: attributes [[NUW]] = { nounwind optsize{{.*}} } // CHECK: attributes [[AI]] = { alwaysinline nounwind optsize{{.*}} } // CHECK: attributes [[NUW_OS_RN]] = { nounwind optsize readnone{{.*}} } -// CHECK: attributes [[ALIGN]] = { nounwind optsize alignstack=16{{.*}} } +// CHECK: attributes [[SR]] = { nounwind optsize{{.*}} "stackrealign"{{.*}} } // CHECK: attributes [[RT]] = { nounwind optsize returns_twice{{.*}} } // CHECK: attributes [[NR]] = { noreturn optsize } // CHECK: attributes [[NUW_RN]] = { nounwind optsize readnone } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
