[clang] [llvm] [BoundsSan] Update BoundsChecking.cpp to use no-merge attribute where… (PR #120620)

[Thurston Dang via llvm-commits]

https://github.com/thurstond created https://github.com/llvm/llvm-project/pull/120620

… applicable

https://github.com/llvm/llvm-project/pull/65972 introduced -ubsan-unique-traps and -bounds-checking-unique-traps, which attach the function size to the ubsantrap intrinsic.

https://github.com/llvm/llvm-project/pull/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.

>From 954e3e4096c4e45baf5470aa678a0fee96db7691 Mon Sep 17 00:00:00 2001
From: Thurston Dang <thurston at google.com>
Date: Thu, 19 Dec 2024 18:46:38 +0000
Subject: [PATCH] [BoundsSan] Update BoundsChecking.cpp to use no-merge
 attribute where applicable

https://github.com/llvm/llvm-project/pull/65972 introduced
-ubsan-unique-traps and -bounds-checking-unique-traps, which attach the function size to the ubsantrap intrinsic.

https://github.com/llvm/llvm-project/pull/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.
---
 clang/test/CodeGen/bounds-checking.c                   | 5 +++--
 llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp | 4 +++-
 2 files changed, 6 insertions(+), 3 deletions(-)

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
+}