[llvm] [CGData][Merger] Avoid merging the attached call target (PR #121030)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-aarch64

Author: Kyungwoo Lee (kyulee-com)

<details>
<summary>Changes</summary>

For global function merging, the target of the arc-attached call must be a constant and cannot be parameterized.
This change adds a check to bypass this case in `canParameterizeCallOperand()`.

---
Full diff: https://github.com/llvm/llvm-project/pull/121030.diff


2 Files Affected:

- (modified) llvm/lib/CodeGen/GlobalMergeFunctions.cpp (+9-3) 
- (added) llvm/test/CodeGen/AArch64/cgdata-no-merge-attached-call-garget.ll (+37) 


``````````diff
diff --git a/llvm/lib/CodeGen/GlobalMergeFunctions.cpp b/llvm/lib/CodeGen/GlobalMergeFunctions.cpp
index c8f1b98c9a18e9..b5863e0551b78c 100644
--- a/llvm/lib/CodeGen/GlobalMergeFunctions.cpp
+++ b/llvm/lib/CodeGen/GlobalMergeFunctions.cpp
@@ -60,11 +60,17 @@ static bool canParameterizeCallOperand(const CallBase *CI, unsigned OpIdx) {
     if (Name.starts_with("__dtrace"))
       return false;
   }
-  if (isCalleeOperand(CI, OpIdx) &&
-      CI->getOperandBundle(LLVMContext::OB_ptrauth).has_value()) {
+  if (isCalleeOperand(CI, OpIdx)) {
     // The operand is the callee and it has already been signed. Ignore this
     // because we cannot add another ptrauth bundle to the call instruction.
-    return false;
+    if (CI->getOperandBundle(LLVMContext::OB_ptrauth).has_value())
+      return false;
+  } else {
+    // The target of the arc-attached call must be a constant and cannot be
+    // parameterized.
+    if (CI->isOperandBundleOfType(llvm::LLVMContext::OB_clang_arc_attachedcall,
+                                  OpIdx))
+      return false;
   }
   return true;
 }
diff --git a/llvm/test/CodeGen/AArch64/cgdata-no-merge-attached-call-garget.ll b/llvm/test/CodeGen/AArch64/cgdata-no-merge-attached-call-garget.ll
new file mode 100644
index 00000000000000..1163314062df1b
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/cgdata-no-merge-attached-call-garget.ll
@@ -0,0 +1,37 @@
+; This test verifies that two similar functions, f1 and f2, are not merged
+; when their attached call targets differ, since these targets cannot be parameterized.
+
+; RUN: llc -mtriple=arm64-apple-darwin -enable-global-merge-func=true < %s | FileCheck %s
+
+; CHECK-NOT: _f1.Tgm
+; CHECK-NOT: _f2.Tgm
+
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-apple-darwin"
+
+define i64 @f1(ptr %0) {
+  %2 = call ptr @g1(ptr %0, i32 0) minsize [ "clang.arc.attachedcall"(ptr @llvm.objc.unsafeClaimAutoreleasedReturnValue) ]
+  tail call void (...) @llvm.objc.clang.arc.noop.use(ptr %2)
+  %3 = call i64 @g2(ptr %2)
+  tail call void @objc_release(ptr %2)
+  %4 = tail call i64 @g3(i64 %3)
+  ret i64 %4
+}
+
+define i64 @f2(ptr %0) {
+  %2 = call ptr @g1(ptr %0, i32 0) minsize [ "clang.arc.attachedcall"(ptr @llvm.objc.retainAutoreleasedReturnValue) ]
+  tail call void (...) @llvm.objc.clang.arc.noop.use(ptr %2)
+  %3 = call i64 @g2(ptr %2)
+  tail call void @objc_release(ptr %2)
+  %4 = tail call i64 @g3(i64 %3)
+  ret i64 %4
+}
+
+declare ptr @g1(ptr, i32)
+declare i64 @g2(ptr)
+declare i64 @g3(i64)
+
+declare void @llvm.objc.clang.arc.noop.use(...)
+declare ptr @llvm.objc.unsafeClaimAutoreleasedReturnValue(ptr)
+declare ptr @llvm.objc.retainAutoreleasedReturnValue(ptr)
+declare void @objc_release(ptr)

``````````

</details>


https://github.com/llvm/llvm-project/pull/121030