[llvm] [MTE] fix bug that prevented stack coloring with MTE (PR #84422)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-aarch64

Author: Florian Mayer (fmayer)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/84422.diff


5 Files Affected:

- (modified) llvm/include/llvm/Transforms/Utils/MemoryTaggingSupport.h (+1) 
- (modified) llvm/lib/Target/AArch64/AArch64StackTagging.cpp (+4-1) 
- (modified) llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp (+2-6) 
- (modified) llvm/lib/Transforms/Utils/MemoryTaggingSupport.cpp (+5) 
- (modified) llvm/test/CodeGen/AArch64/stack-tagging-stack-coloring.ll (+8-8) 


``````````diff
diff --git a/llvm/include/llvm/Transforms/Utils/MemoryTaggingSupport.h b/llvm/include/llvm/Transforms/Utils/MemoryTaggingSupport.h
index eb00e6c4e856df..df61f60de4f261 100644
--- a/llvm/include/llvm/Transforms/Utils/MemoryTaggingSupport.h
+++ b/llvm/include/llvm/Transforms/Utils/MemoryTaggingSupport.h
@@ -78,6 +78,7 @@ class StackInfoBuilder {
 
 uint64_t getAllocaSizeInBytes(const AllocaInst &AI);
 void alignAndPadAlloca(memtag::AllocaInfo &Info, llvm::Align Align);
+bool isLifetimeIntrinsic(Value *V);
 
 } // namespace memtag
 } // namespace llvm
diff --git a/llvm/lib/Target/AArch64/AArch64StackTagging.cpp b/llvm/lib/Target/AArch64/AArch64StackTagging.cpp
index ef7c517732ef3f..53418694bf26c1 100644
--- a/llvm/lib/Target/AArch64/AArch64StackTagging.cpp
+++ b/llvm/lib/Target/AArch64/AArch64StackTagging.cpp
@@ -533,7 +533,10 @@ bool AArch64StackTagging::runOnFunction(Function &Fn) {
     if (Info.AI->hasName())
       TagPCall->setName(Info.AI->getName() + ".tag");
     // Does not replace metadata, so we don't have to handle DPValues.
-    Info.AI->replaceNonMetadataUsesWith(TagPCall);
+    Info.AI->replaceUsesWithIf(TagPCall, [](const Use &U) {
+      auto *User = U.getUser();
+      return !memtag::isLifetimeIntrinsic(User);
+    });
     TagPCall->setOperand(0, Info.AI);
 
     // Calls to functions that may return twice (e.g. setjmp) confuse the
diff --git a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
index 6bae679e11be23..88553d49b1b5e9 100644
--- a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -1391,11 +1391,6 @@ bool HWAddressSanitizer::instrumentLandingPads(
   return true;
 }
 
-static bool isLifetimeIntrinsic(Value *V) {
-  auto *II = dyn_cast<IntrinsicInst>(V);
-  return II && II->isLifetimeStartOrEnd();
-}
-
 static DbgAssignIntrinsic *DynCastToDbgAssign(DbgVariableIntrinsic *DVI) {
   return dyn_cast<DbgAssignIntrinsic>(DVI);
 }
@@ -1455,7 +1450,8 @@ bool HWAddressSanitizer::instrumentStack(memtag::StackInfo &SInfo,
 
     AI->replaceUsesWithIf(Replacement, [AICast, AILong](const Use &U) {
       auto *User = U.getUser();
-      return User != AILong && User != AICast && !isLifetimeIntrinsic(User);
+      return User != AILong && User != AICast &&
+             !memtag::isLifetimeIntrinsic(User);
     });
 
     // Helper utility for adding DW_OP_LLVM_tag_offset to debug-info records,
diff --git a/llvm/lib/Transforms/Utils/MemoryTaggingSupport.cpp b/llvm/lib/Transforms/Utils/MemoryTaggingSupport.cpp
index bfe474d8204578..f4b9b155827a99 100644
--- a/llvm/lib/Transforms/Utils/MemoryTaggingSupport.cpp
+++ b/llvm/lib/Transforms/Utils/MemoryTaggingSupport.cpp
@@ -236,5 +236,10 @@ void alignAndPadAlloca(memtag::AllocaInfo &Info, llvm::Align Alignment) {
   Info.AI = NewAI;
 }
 
+bool isLifetimeIntrinsic(Value *V) {
+  auto *II = dyn_cast<IntrinsicInst>(V);
+  return II && II->isLifetimeStartOrEnd();
+}
+
 } // namespace memtag
 } // namespace llvm
diff --git a/llvm/test/CodeGen/AArch64/stack-tagging-stack-coloring.ll b/llvm/test/CodeGen/AArch64/stack-tagging-stack-coloring.ll
index 6eb72013fb0ed0..81349620fb7725 100644
--- a/llvm/test/CodeGen/AArch64/stack-tagging-stack-coloring.ll
+++ b/llvm/test/CodeGen/AArch64/stack-tagging-stack-coloring.ll
@@ -1,20 +1,20 @@
 ; Test that storage for allocas with disjoint lifetimes is reused with stack
 ; tagging.
 
-; RUN: opt -S -aarch64-stack-tagging %s -o - | \
-; RUN:   llc -no-stack-coloring=false -o - | \
+; RUN: opt -S -aarch64-stack-tagging -stack-tagging-use-stack-safety=0 %s -o - | \
+; RUN:   llc --mattr=+mte -no-stack-coloring=false -o - | \
 ; RUN:   FileCheck %s --check-prefix=COLOR
-; RUN: opt -S -aarch64-stack-tagging %s -o - | \
-; RUN:   llc -no-stack-coloring=true -o - | \
+; RUN: opt -S -aarch64-stack-tagging %s -stack-tagging-use-stack-safety=0 -o - | \
+; RUN:   llc --mattr=+mte -no-stack-coloring=true -o - | \
 ; RUN:   FileCheck %s --check-prefix=NOCOLOR
 
 target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
-target triple = "aarch64-unknown-linux-android29"
+target triple = "aarch64"
 
-; COLOR: sub	sp, sp, #192
-; NOCOLOR: sub	sp, sp, #320
+; COLOR: sub	sp, sp, #208
+; NOCOLOR: sub	sp, sp, #336
 
-define i32 @myCall_w2(i32 %in) sanitize_hwaddress {
+define i32 @myCall_w2(i32 %in) sanitize_memtag {
 entry:
   %a = alloca [17 x ptr], align 8
   %a2 = alloca [16 x ptr], align 8

``````````

</details>


https://github.com/llvm/llvm-project/pull/84422