[llvm] Fix incorrect debug attribution for inlined allocas (PR #144345)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Shivam Kunwar (phyBrackets)

<details>
<summary>Changes</summary>

Fixing #<!-- -->142662 

Fix incorrect debug attribution for inlined allocas, Clear debug locations from all inlined alloca instructions to prevent stack protection and other generated code from inheriting incorrect source line attributions from the callee function.

---
Full diff: https://github.com/llvm/llvm-project/pull/144345.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/Utils/InlineFunction.cpp (+10) 


``````````diff
diff --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp
index 21467a909af10..312b4888ee6e7 100644
--- a/llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ b/llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -2703,6 +2703,16 @@ llvm::InlineResult llvm::InlineFunction(CallBase &CB, InlineFunctionInfo &IFI,
     // Remember the first block that is newly cloned over.
     FirstNewBlock = LastBlock; ++FirstNewBlock;
 
+    // Clear debug locations for all inlined allocas to prevent stack protection
+    // code from inheriting incorrect source attribution
+    for (Function::iterator BB = FirstNewBlock, E = Caller->end(); BB != E; ++BB) {
+     for (BasicBlock::iterator I = BB->begin(), IE = BB->end(); I != IE; ++I) {
+        if (auto *AI = dyn_cast<AllocaInst>(I)) {
+          AI->setDebugLoc(DebugLoc());
+        }
+      }
+    }
+
     // Insert retainRV/clainRV runtime calls.
     objcarc::ARCInstKind RVCallKind = objcarc::getAttachedARCFunctionKind(&CB);
     if (RVCallKind != objcarc::ARCInstKind::None)

``````````

</details>


https://github.com/llvm/llvm-project/pull/144345