[BoundsSan] Update BoundsChecking.cpp to use no-merge attribute where applicable

[thurstond]

#65972 introduced -ubsan-unique-traps and -bounds-checking-unique-traps, which attach the function size to the ubsantrap intrinsic.

#117651 changed ubsan-unique-traps to use nomerge instead of the function size, but did not update -bounds-checking-unique-traps. This patch adds nomerge to bounds-checking-unique-traps.

[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-llvm-transforms

Author: Thurston Dang (thurstond)

Changes

… applicable

#65972 introduced -ubsan-unique-traps and -bounds-checking-unique-traps, which attach the function size to the ubsantrap intrinsic.

#117651 changed ubsan-unique-traps to use nomerge instead of the function size, but did not update -bounds-checking-unique-traps. This patch adds nomerge to bounds-checking-unique-traps.

---

Full diff: https://github.com/llvm/llvm-project/pull/120620.diff

2 Files Affected:

• (modified) clang/test/CodeGen/bounds-checking.c (+3-2)
• (modified) llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp (+3-1)

diff --git a/clang/test/CodeGen/bounds-checking.c b/clang/test/CodeGen/bounds-checking.c
index f6c4880e70a150..2e0f6fb491e2c8 100644
--- a/clang/test/CodeGen/bounds-checking.c
+++ b/clang/test/CodeGen/bounds-checking.c
@@ -73,11 +73,11 @@ char B[10];
 char B2[10];
 // CHECK-LABEL: @f8
 void f8(int i, int k) {
-  // NOOPTLOCAL: call void @llvm.ubsantrap(i8 3)
+  // NOOPTLOCAL: call void @llvm.ubsantrap(i8 3) #[[ATTR1:[0-9]+]]
   // NOOPTARRAY: call void @llvm.ubsantrap(i8 18)
   B[i] = '\0';
 
-  // NOOPTLOCAL: call void @llvm.ubsantrap(i8 5)
+  // NOOPTLOCAL: call void @llvm.ubsantrap(i8 5) #[[ATTR1:[0-9]+]]
   // NOOPTARRAY: call void @llvm.ubsantrap(i8 18)
   B2[k] = '\0';
 }
@@ -90,3 +90,4 @@ struct S {
 struct S *f9(int i) {
   return &s[i];
 }
+// NOOPTLOCAL: attributes #[[ATTR1]] = { nomerge noreturn nounwind }
diff --git a/llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp b/llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp
index c86d967716a5a0..1a2dc5984523ec 100644
--- a/llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp
+++ b/llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp
@@ -196,8 +196,10 @@ static bool addBoundsChecking(Function &F, TargetLibraryInfo &TLI,
 
     CallInst *TrapCall;
     if (DebugTrapBB) {
+      // Ideally we would use the SanitizerHandler::OutOfBounds constant
       TrapCall = IRB.CreateIntrinsic(
           IntrID, {}, ConstantInt::get(IRB.getInt8Ty(), Fn->size()));
+      TrapCall->addFnAttr(llvm::Attribute::NoMerge);
     } else {
       TrapCall = IRB.CreateIntrinsic(IntrID, {}, {});
     }
@@ -251,4 +253,4 @@ void BoundsCheckingPass::printPipeline(
     OS << "<rt-abort>";
     break;
   }
-}
\ No newline at end of file
+}