Remove dangling initializers in GlobalDCE
GlobalDCE deletes global vars and updates their initializers to nullptr
while leaving underlying constants to be cleaned up later by its uses.
The clean up may never happen, fix this by forcing it every time it's
safe to destroy constants.
Final patch by Rafael Espindola
http://reviews.llvm.org/D4931
<rdar://problem/17523868>
llvm-svn: 216390
diff --git a/llvm/lib/Transforms/IPO/GlobalDCE.cpp b/llvm/lib/Transforms/IPO/GlobalDCE.cpp
index 7e7a4c0..e50cdb7 100644
--- a/llvm/lib/Transforms/IPO/GlobalDCE.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalDCE.cpp
@@ -22,6 +22,7 @@
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
#include "llvm/Transforms/Utils/CtorUtils.h"
+#include "llvm/Transforms/Utils/GlobalStatus.h"
#include "llvm/Pass.h"
using namespace llvm;
@@ -141,7 +142,12 @@
I != E; ++I)
if (!AliveGlobals.count(I)) {
DeadGlobalVars.push_back(I); // Keep track of dead globals
- I->setInitializer(nullptr);
+ if (I->hasInitializer()) {
+ Constant *Init = I->getInitializer();
+ I->setInitializer(nullptr);
+ if (isSafeToDestroyConstant(Init))
+ Init->destroyConstant();
+ }
}
// The second pass drops the bodies of functions which are dead...
diff --git a/llvm/lib/Transforms/Utils/GlobalStatus.cpp b/llvm/lib/Transforms/Utils/GlobalStatus.cpp
index 33e34a9..97a0b4e 100644
--- a/llvm/lib/Transforms/Utils/GlobalStatus.cpp
+++ b/llvm/lib/Transforms/Utils/GlobalStatus.cpp
@@ -35,6 +35,9 @@
if (isa<GlobalValue>(C))
return false;
+ if (isa<ConstantInt>(C) || isa<ConstantFP>(C))
+ return false;
+
for (const User *U : C->users())
if (const Constant *CU = dyn_cast<Constant>(U)) {
if (!isSafeToDestroyConstant(CU))