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
llvm-svn: 330331
diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index f98faeb..5e842fa 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -1941,13 +1941,8 @@
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 @@
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 @@
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);