From 0f57a98a65df5e617ed0adcf0ca0877745c84a79 Mon Sep 17 00:00:00 2001
From: Joey Gouly <joey.gouly@arm.com>
Date: Wed, 10 Apr 2013 10:37:38 +0000
Subject: [PATCH] Change CloneFunctionInto to always clone Argument attributes
 induvidually, rather than checking if the source and destination have the
 same number of arguments and copying the attributes over directly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179169 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Utils/CloneFunction.cpp | 41 ++++++++++++--------------
 unittests/Transforms/Utils/Cloning.cpp | 29 +++++++++++++++++-
 2 files changed, 47 insertions(+), 23 deletions(-)

diff --git a/lib/Transforms/Utils/CloneFunction.cpp b/lib/Transforms/Utils/CloneFunction.cpp
index 63d7a1d52aa..be8d39e128a 100644
--- a/lib/Transforms/Utils/CloneFunction.cpp
+++ b/lib/Transforms/Utils/CloneFunction.cpp
@@ -87,29 +87,26 @@ void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
     assert(VMap.count(I) && "No mapping from source argument specified!");
 #endif
 
-  // Clone any attributes.
-  if (NewFunc->arg_size() == OldFunc->arg_size())
-    NewFunc->copyAttributesFrom(OldFunc);
-  else {
-    //Some arguments were deleted with the VMap. Copy arguments one by one
-    for (Function::const_arg_iterator I = OldFunc->arg_begin(), 
-           E = OldFunc->arg_end(); I != E; ++I)
-      if (Argument* Anew = dyn_cast<Argument>(VMap[I])) {
-        AttributeSet attrs = OldFunc->getAttributes()
-          .getParamAttributes(I->getArgNo() + 1);
-        if (attrs.getNumSlots() > 0)
-          Anew->addAttr(attrs);
-      }
-    NewFunc->setAttributes(NewFunc->getAttributes()
-                           .addAttributes(NewFunc->getContext(),
-                                          AttributeSet::ReturnIndex,
-                                          OldFunc->getAttributes()));
-    NewFunc->setAttributes(NewFunc->getAttributes()
-                           .addAttributes(NewFunc->getContext(),
-                                          AttributeSet::FunctionIndex,
-                                          OldFunc->getAttributes()));
+  AttributeSet OldAttrs = OldFunc->getAttributes();
+  // Clone any argument attributes that are present in the VMap.
+  for (Function::const_arg_iterator I = OldFunc->arg_begin(),
+                                    E = OldFunc->arg_end();
+       I != E; ++I)
+    if (Argument *Anew = dyn_cast<Argument>(VMap[I])) {
+      AttributeSet attrs =
+          OldAttrs.getParamAttributes(I->getArgNo() + 1);
+      if (attrs.getNumSlots() > 0)
+        Anew->addAttr(attrs);
+    }
 
-  }
+  NewFunc->setAttributes(NewFunc->getAttributes()
+                         .addAttributes(NewFunc->getContext(),
+                                        AttributeSet::ReturnIndex,
+                                        OldAttrs.getRetAttributes()));
+  NewFunc->setAttributes(NewFunc->getAttributes()
+                         .addAttributes(NewFunc->getContext(),
+                                        AttributeSet::FunctionIndex,
+                                        OldAttrs.getFnAttributes()));
 
   // Loop over all of the basic blocks in the function, cloning them as
   // appropriate.  Note that we save BE this way in order to handle cloning of
diff --git a/unittests/Transforms/Utils/Cloning.cpp b/unittests/Transforms/Utils/Cloning.cpp
index cd304e72008..5930d5ef98d 100644
--- a/unittests/Transforms/Utils/Cloning.cpp
+++ b/unittests/Transforms/Utils/Cloning.cpp
@@ -7,12 +7,15 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/IR/Instructions.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/IR/Argument.h"
 #include "llvm/IR/Constant.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/LLVMContext.h"
+#include "llvm/Transforms/Utils/Cloning.h"
 #include "gtest/gtest.h"
 
 using namespace llvm;
@@ -143,4 +146,28 @@ TEST_F(CloneInstruction, Exact) {
   EXPECT_TRUE(this->clone(SDiv)->isExact());
 }
 
+TEST_F(CloneInstruction, Attributes) {
+  Type *ArgTy1[] = { Type::getInt32PtrTy(context) };
+  FunctionType *FT1 =  FunctionType::get(Type::getVoidTy(context), ArgTy1, false);
+
+  Function *F1 = Function::Create(FT1, Function::ExternalLinkage);
+  BasicBlock *BB = BasicBlock::Create(context, "", F1);
+  IRBuilder<> Builder(BB);
+  Builder.CreateRetVoid();
+
+  Function *F2 = Function::Create(FT1, Function::ExternalLinkage);
+
+  Attribute::AttrKind AK[] = { Attribute::NoCapture };
+  AttributeSet AS = AttributeSet::get(context, 0, AK);
+  Argument *A = F1->arg_begin();
+  A->addAttr(AS);
+
+  SmallVector<ReturnInst*, 4> Returns;
+  ValueToValueMapTy VMap;
+  VMap[A] = UndefValue::get(A->getType());
+
+  CloneFunctionInto(F2, F1, VMap, false, Returns);
+  EXPECT_FALSE(F2->arg_begin()->hasNoCaptureAttr());
+}
+
 }
-- 
2.34.1