[clang] 3568976 - Reland^2 "Fix __cfi_check not aligned to 4k on relocatable files with no executable code"

[Yi Kong via cfe-commits]

Author: Yi Kong
Date: 2023-08-17T16:33:46+09:00
New Revision: 3568976375e305a7a41d62b9164ede7571ee16c5

URL: https://github.com/llvm/llvm-project/commit/3568976375e305a7a41d62b9164ede7571ee16c5
DIFF: https://github.com/llvm/llvm-project/commit/3568976375e305a7a41d62b9164ede7571ee16c5.diff

LOG: Reland^2 "Fix __cfi_check not aligned to 4k on relocatable files with no executable code"

This reverts commit 043d03d25bd7eadef66685de298342b35fe6b466.

Added: 
    

Modified: 
    clang/lib/CodeGen/CGExpr.cpp
    clang/test/CodeGen/cfi-check-fail.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 0f06f3d4089ad8..76bbeba468db64 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -3430,14 +3430,12 @@ void CodeGenFunction::EmitCfiCheckStub() {
   llvm::Function *F = llvm::Function::Create(
       llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy, Int8PtrTy}, false),
       llvm::GlobalValue::WeakAnyLinkage, "__cfi_check", M);
+  F->setAlignment(llvm::Align(4096));
   CGM.setDSOLocal(F);
   llvm::BasicBlock *BB = llvm::BasicBlock::Create(Ctx, "entry", F);
-  // FIXME: consider emitting an intrinsic call like
-  // call void @llvm.cfi_check(i64 %0, i8* %1, i8* %2)
-  // which can be lowered in CrossDSOCFI pass to the actual contents of
-  // __cfi_check. This would allow inlining of __cfi_check calls.
-  llvm::CallInst::Create(
-      llvm::Intrinsic::getDeclaration(M, llvm::Intrinsic::trap), "", BB);
+  // CrossDSOCFI pass is not executed if there is no executable code.
+  SmallVector<llvm::Value*> Args{F->getArg(2), F->getArg(1)};
+  llvm::CallInst::Create(M->getFunction("__cfi_check_fail"), Args, "", BB);
   llvm::ReturnInst::Create(Ctx, nullptr, BB);
 }
 

diff  --git a/clang/test/CodeGen/cfi-check-fail.c b/clang/test/CodeGen/cfi-check-fail.c
index a4d940641090e5..2f12cee9dec602 100644
--- a/clang/test/CodeGen/cfi-check-fail.c
+++ b/clang/test/CodeGen/cfi-check-fail.c
@@ -72,7 +72,7 @@ void caller(void (*f)(void)) {
 // CHECK: [[CONT5]]:
 // CHECK:   ret void
 
-// CHECK: define weak void @__cfi_check(i64 %0, ptr %1, ptr %2)
+// CHECK: define weak void @__cfi_check(i64 %[[TYPE:.*]], ptr %[[ADDR:.*]], ptr %[[DATA:.*]]) align 4096
 // CHECK-NOT: }
-// CHECK: call void @llvm.trap()
+// CHECK: call void @__cfi_check_fail(ptr %[[DATA]], ptr %[[ADDR]])
 // CHECK-NEXT: ret void