Fix dangling IPOAmendableCB function_ref.

[hokein]

The IPOAmendableCB's type is llvm::function_ref, it is error-prone to write code (e.g.

llvm-project/llvm/lib/Transforms/IPO/OpenMPOpt.cpp

Line 5812 in 5656cbc

AC.IPOAmendableCB = [](const Function &F) {

) that assign a temporary lambda to an IPOAmendableCB object, which is a use-after-free issue.

This patch changes the IPOAmendableCB to std::function, to avoid the dangling issue.

[llvmbot]

@llvm/pr-subscribers-backend-amdgpu

Author: Haojian Wu (hokein)

Changes

A temporary lambda is assigned to a llvm::function_ref, this lambda is destroyed at the end of the full expression, any use of the function_ref afterwards is undefined behavior.

---

Full diff: https://github.com/llvm/llvm-project/pull/120698.diff

2 Files Affected:

• (modified) llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp (+2-1)
• (modified) llvm/lib/Transforms/IPO/OpenMPOpt.cpp (+2-1)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp b/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
index 21f9c50c352563..227a49fcc1a491 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
@@ -1352,9 +1352,10 @@ static bool runImpl(Module &M, AnalysisGetter &AG, TargetMachine &TM,
         return !AMDGPU::isEntryFunctionCC(Callee.getCallingConv()) &&
                (NumAssumedCallees <= IndirectCallSpecializationThreshold);
       };
-  AC.IPOAmendableCB = [](const Function &F) {
+  auto IPOAmendableCB = [](const Function &F) {
     return F.getCallingConv() == CallingConv::AMDGPU_KERNEL;
   };
+  AC.IPOAmendableCB = IPOAmendableCB;
 
   Attributor A(Functions, InfoCache, AC);
 
diff --git a/llvm/lib/Transforms/IPO/OpenMPOpt.cpp b/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
index b40ab357670b86..ee4e4a85d5a0e0 100644
--- a/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
+++ b/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
@@ -5809,9 +5809,10 @@ PreservedAnalyses OpenMPOptPass::run(Module &M, ModuleAnalysisManager &AM) {
   AC.OREGetter = OREGetter;
   AC.PassName = DEBUG_TYPE;
   AC.InitializationCallback = OpenMPOpt::registerAAsForFunction;
-  AC.IPOAmendableCB = [](const Function &F) {
+  auto IPOAmendableCB = [](const Function &F) {
     return F.hasFnAttribute("kernel");
   };
+  AC.IPOAmendableCB = IPOAmendableCB;
 
   Attributor A(Functions, InfoCache, AC);
 

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: Haojian Wu (hokein)

Changes

A temporary lambda is assigned to a llvm::function_ref, this lambda is destroyed at the end of the full expression, any use of the function_ref afterwards is undefined behavior.

---

Full diff: https://github.com/llvm/llvm-project/pull/120698.diff

2 Files Affected:

• (modified) llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp (+2-1)
• (modified) llvm/lib/Transforms/IPO/OpenMPOpt.cpp (+2-1)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp b/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
index 21f9c50c352563..227a49fcc1a491 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
@@ -1352,9 +1352,10 @@ static bool runImpl(Module &M, AnalysisGetter &AG, TargetMachine &TM,
         return !AMDGPU::isEntryFunctionCC(Callee.getCallingConv()) &&
                (NumAssumedCallees <= IndirectCallSpecializationThreshold);
       };
-  AC.IPOAmendableCB = [](const Function &F) {
+  auto IPOAmendableCB = [](const Function &F) {
     return F.getCallingConv() == CallingConv::AMDGPU_KERNEL;
   };
+  AC.IPOAmendableCB = IPOAmendableCB;
 
   Attributor A(Functions, InfoCache, AC);
 
diff --git a/llvm/lib/Transforms/IPO/OpenMPOpt.cpp b/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
index b40ab357670b86..ee4e4a85d5a0e0 100644
--- a/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
+++ b/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
@@ -5809,9 +5809,10 @@ PreservedAnalyses OpenMPOptPass::run(Module &M, ModuleAnalysisManager &AM) {
   AC.OREGetter = OREGetter;
   AC.PassName = DEBUG_TYPE;
   AC.InitializationCallback = OpenMPOpt::registerAAsForFunction;
-  AC.IPOAmendableCB = [](const Function &F) {
+  auto IPOAmendableCB = [](const Function &F) {
     return F.hasFnAttribute("kernel");
   };
+  AC.IPOAmendableCB = IPOAmendableCB;
 
   Attributor A(Functions, InfoCache, AC);
 

[jdoerfert]

LG