From 41be2fb1f9e9b8f796effb81c2bee6cf397136cf Mon Sep 17 00:00:00 2001
From: Nuno Lopes <nunoplopes@sapo.pt>
Date: Mon, 31 Dec 2012 16:23:48 +0000
Subject: [PATCH] add support for GlobalAlias to ObjectSizeOffsetVisitor

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171303 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Analysis/MemoryBuiltins.h | 1 +
 lib/Analysis/MemoryBuiltins.cpp        | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/include/llvm/Analysis/MemoryBuiltins.h b/include/llvm/Analysis/MemoryBuiltins.h
index a797374a593..9502f621b15 100644
--- a/include/llvm/Analysis/MemoryBuiltins.h
+++ b/include/llvm/Analysis/MemoryBuiltins.h
@@ -191,6 +191,7 @@ public:
   SizeOffsetType visitExtractElementInst(ExtractElementInst &I);
   SizeOffsetType visitExtractValueInst(ExtractValueInst &I);
   SizeOffsetType visitGEPOperator(GEPOperator &GEP);
+  SizeOffsetType visitGlobalAlias(GlobalAlias &GA);
   SizeOffsetType visitGlobalVariable(GlobalVariable &GV);
   SizeOffsetType visitIntToPtrInst(IntToPtrInst&);
   SizeOffsetType visitLoadInst(LoadInst &I);
diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp
index 2503bfa2161..a565617f21b 100644
--- a/lib/Analysis/MemoryBuiltins.cpp
+++ b/lib/Analysis/MemoryBuiltins.cpp
@@ -399,6 +399,8 @@ SizeOffsetType ObjectSizeOffsetVisitor::compute(Value *V) {
     return visitArgument(*A);
   if (ConstantPointerNull *P = dyn_cast<ConstantPointerNull>(V))
     return visitConstantPointerNull(*P);
+  if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
+    return visitGlobalAlias(*GA);
   if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
     return visitGlobalVariable(*GV);
   if (UndefValue *UV = dyn_cast<UndefValue>(V))
@@ -517,6 +519,12 @@ SizeOffsetType ObjectSizeOffsetVisitor::visitGEPOperator(GEPOperator &GEP) {
   return std::make_pair(PtrData.first, PtrData.second + Offset);
 }
 
+SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalAlias(GlobalAlias &GA) {
+  if (GA.mayBeOverridden())
+    return unknown();
+  return compute(GA.getAliasee());
+}
+
 SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalVariable(GlobalVariable &GV){
   if (!GV.hasDefinitiveInitializer())
     return unknown();
@@ -629,6 +637,7 @@ SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute_(Value *V) {
   } else if (isa<Argument>(V) ||
              (isa<ConstantExpr>(V) &&
               cast<ConstantExpr>(V)->getOpcode() == Instruction::IntToPtr) ||
+             isa<GlobalAlias>(V) ||
              isa<GlobalVariable>(V)) {
     // ignore values where we cannot do more than what ObjectSizeVisitor can
     Result = unknown();
-- 
2.34.1