#include "llvm/Constants.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
-#include "llvm/Support/Compiler.h"
-#include <set>
using namespace llvm;
STATISTIC(NumAliases , "Number of global aliases removed");
STATISTIC(NumVariables, "Number of global variables removed");
namespace {
- struct VISIBILITY_HIDDEN GlobalDCE : public ModulePass {
+ struct GlobalDCE : public ModulePass {
static char ID; // Pass identification, replacement for typeid
- GlobalDCE() : ModulePass(&ID) {}
+ GlobalDCE() : ModulePass(ID) {}
// run - Do the GlobalDCE pass on the specified module, optionally updating
// the specified callgraph to reflect the changes.
bool runOnModule(Module &M);
private:
- std::set<GlobalValue*> AliveGlobals;
+ SmallPtrSet<GlobalValue*, 32> AliveGlobals;
/// GlobalIsNeeded - mark the specific global value as needed, and
/// recursively mark anything that it uses as also needed.
}
char GlobalDCE::ID = 0;
-static RegisterPass<GlobalDCE> X("globaldce", "Dead Global Elimination");
+INITIALIZE_PASS(GlobalDCE, "globaldce",
+ "Dead Global Elimination", false, false);
ModulePass *llvm::createGlobalDCEPass() { return new GlobalDCE(); }
// The first pass is to drop initializers of global variables which are dead.
std::vector<GlobalVariable*> DeadGlobalVars; // Keep track of dead globals
- for (Module::global_iterator I = M.global_begin(), E = M.global_end(); I != E; ++I)
+ for (Module::global_iterator I = M.global_begin(), E = M.global_end();
+ I != E; ++I)
if (!AliveGlobals.count(I)) {
DeadGlobalVars.push_back(I); // Keep track of dead globals
I->setInitializer(0);
// Make sure that all memory is released
AliveGlobals.clear();
- // Remove dead metadata.
- Changed |= M.getContext().RemoveDeadMetadata();
return Changed;
}
/// GlobalIsNeeded - the specific global value as needed, and
/// recursively mark anything that it uses as also needed.
void GlobalDCE::GlobalIsNeeded(GlobalValue *G) {
- std::set<GlobalValue*>::iterator I = AliveGlobals.find(G);
-
// If the global is already in the set, no need to reprocess it.
- if (I != AliveGlobals.end()) return;
-
- // Otherwise insert it now, so we do not infinitely recurse
- AliveGlobals.insert(I, G);
-
+ if (!AliveGlobals.insert(G))
+ return;
+
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(G)) {
// If this is a global variable, we must make sure to add any global values
// referenced by the initializer to the alive set.
// operands. Any operands of these types must be processed to ensure that
// any globals used will be marked as needed.
Function *F = cast<Function>(G);
- // For all basic blocks...
+
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
- // For all instructions...
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
- // For all operands...
for (User::op_iterator U = I->op_begin(), E = I->op_end(); U != E; ++U)
if (GlobalValue *GV = dyn_cast<GlobalValue>(*U))
GlobalIsNeeded(GV);
void GlobalDCE::MarkUsedGlobalsAsNeeded(Constant *C) {
if (GlobalValue *GV = dyn_cast<GlobalValue>(C))
- GlobalIsNeeded(GV);
- else {
- // Loop over all of the operands of the constant, adding any globals they
- // use to the list of needed globals.
- for (User::op_iterator I = C->op_begin(), E = C->op_end(); I != E; ++I)
- MarkUsedGlobalsAsNeeded(cast<Constant>(*I));
- }
+ return GlobalIsNeeded(GV);
+
+ // Loop over all of the operands of the constant, adding any globals they
+ // use to the list of needed globals.
+ for (User::op_iterator I = C->op_begin(), E = C->op_end(); I != E; ++I)
+ if (Constant *OpC = dyn_cast<Constant>(*I))
+ MarkUsedGlobalsAsNeeded(OpC);
}
// RemoveUnusedGlobalValue - Loop over all of the uses of the specified