From 706cbb3337802b0e8e42df1dea937d4f4797ec68 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Thu, 10 Jul 2014 01:30:39 +0000
Subject: [PATCH] [dfsan] Handle bitcast aliases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212668 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Instrumentation/DataFlowSanitizer.cpp    | 4 ++--
 test/Instrumentation/DataFlowSanitizer/prefix-rename.ll | 8 ++++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
index 3b9212a14e6..799e14bdac3 100644
--- a/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
+++ b/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
@@ -602,7 +602,7 @@ bool DataFlowSanitizer::runOnModule(Module &M) {
     ++i;
     // Don't stop on weak.  We assume people aren't playing games with the
     // instrumentedness of overridden weak aliases.
-    if (Function *F = dyn_cast<Function>(GA->getAliasee())) {
+    if (auto F = dyn_cast<Function>(GA->getBaseObject())) {
       bool GAInst = isInstrumented(GA), FInst = isInstrumented(F);
       if (GAInst && FInst) {
         addGlobalNamePrefix(GA);
@@ -612,7 +612,7 @@ bool DataFlowSanitizer::runOnModule(Module &M) {
         // below will take care of instrumenting it.
         Function *NewF =
             buildWrapperFunction(F, "", GA->getLinkage(), F->getFunctionType());
-        GA->replaceAllUsesWith(NewF);
+        GA->replaceAllUsesWith(ConstantExpr::getBitCast(NewF, GA->getType()));
         NewF->takeName(GA);
         GA->eraseFromParent();
         FnsToInstrument.push_back(NewF);
diff --git a/test/Instrumentation/DataFlowSanitizer/prefix-rename.ll b/test/Instrumentation/DataFlowSanitizer/prefix-rename.ll
index 1a5646074d2..f3c36b17b38 100644
--- a/test/Instrumentation/DataFlowSanitizer/prefix-rename.ll
+++ b/test/Instrumentation/DataFlowSanitizer/prefix-rename.ll
@@ -8,7 +8,15 @@ module asm ".symver f1,f@@version1"
 ; CHECK: @"dfs$f2" = alias {{.*}} @"dfs$f1"
 @f2 = alias void ()* @f1
 
+; CHECK: @"dfs$g2" = alias {{.*}} @"dfs$g1"
+@g2 = alias bitcast (void (i8*)* @g1 to void (i16*)*)
+
 ; CHECK: define void @"dfs$f1"
 define void @f1() {
   ret void
 }
+
+; CHECK: define void @"dfs$g1"
+define void @g1(i8*) {
+  ret void
+}
-- 
2.34.1