//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#include "llvm/Pass.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Compiler.h"
+#include <map>
using namespace llvm;
STATISTIC(NumMerged, "Number of global constants merged");
namespace {
struct VISIBILITY_HIDDEN ConstantMerge : public ModulePass {
+ static char ID; // Pass identification, replacement for typeid
+ ConstantMerge() : ModulePass((intptr_t)&ID) {}
+
// run - For this pass, process all of the globals in the module,
// eliminating duplicate constants.
//
bool runOnModule(Module &M);
};
+ char ConstantMerge::ID = 0;
RegisterPass<ConstantMerge>X("constmerge","Merge Duplicate Global Constants");
}
// because doing so may cause initializers of other globals to be rewritten,
// invalidating the Constant* pointers in CMap.
//
- for (Module::global_iterator GV = M.global_begin(), E = M.global_end();
- GV != E; ++GV)
+ for (Module::global_iterator GVI = M.global_begin(), E = M.global_end();
+ GVI != E; ) {
+ GlobalVariable *GV = GVI++;
+
+ // If this GV is dead, remove it.
+ GV->removeDeadConstantUsers();
+ if (GV->use_empty() && GV->hasInternalLinkage()) {
+ GV->eraseFromParent();
+ continue;
+ }
+
// Only process constants with initializers.
if (GV->isConstant() && GV->hasInitializer()) {
Constant *Init = GV->getInitializer();
} else if (GV->hasInternalLinkage()) { // Yup, this is a duplicate!
// Make all uses of the duplicate constant use the canonical version.
Replacements.push_back(std::make_pair(GV, Slot));
- } else if (GV->hasInternalLinkage()) {
- // Make all uses of the duplicate constant use the canonical version.
- Replacements.push_back(std::make_pair(Slot, GV));
- Slot = GV;
}
}
+ }
if (Replacements.empty())
return MadeChange;