SizeOffsetType ObjectSizeOffsetVisitor::visitGlobalVariable(GlobalVariable &GV){
if (!GV.hasDefinitiveInitializer())
return unknown();
APInt Size(IntTyBits, TD->getTypeAllocSize(GV.getType()->getElementType()));
return std::make_pair(align(Size, GV.getAlignment()), Zero);
}
bool runOnModule(Module &M) override {
// function pointer initialized at compile time
for (Module::global_iterator G = M.global_begin(); G != M.global_end(); G++) {
GlobalVariable *gv = &*G;
if (!gv->hasDefinitiveInitializer())
continue;
Constant *initor = gv->getInitializer();
if (constantFunctionPointerName(initor) || constantTravel(initor))
errs() << *gv << "\n";
}
// function pointer initialized at runtime
for (Module::iterator F = M.begin(); F != M.end(); F++) {
for (inst_iterator I = inst_begin(F); I != inst_end(F); I++) {
if (StoreInst *si = dyn_cast<StoreInst>(&*I)) {
Value *val = si->getValueOperand();
if (constantFunctionPointerName(val))
errs() << *I << "\n";
} else if (CallInst *ci = dyn_cast<CallInst>(&*I)) {
for (unsigned i = 0; i < ci->getNumArgOperands(); i++) {
Value *operand = ci->getArgOperand(i);
if (constantFunctionPointerName(operand))
errs() << *I << "\n";
}
} else if (ReturnInst *ri = dyn_cast<ReturnInst>(&*I)) {
Value *ret = ri->getReturnValue();
if (constantFunctionPointerName(ret))
errs() << *I << "\n";
}
}
}
return false;
}
static void initialiseStore(ShadowBB* BB) {
for(uint32_t i = 0, ilim = GlobalIHP->heap.size(); i != ilim; ++i) {
AllocData& AD = GlobalIHP->heap[i];
ImprovedValSetSingle* Init = new ImprovedValSetSingle();
if(AD.allocValue.isGV()) {
GlobalVariable* G = AD.allocValue.getGV()->G;
if(GlobalIHP->useGlobalInitialisers && G->hasDefinitiveInitializer()) {
Constant* I = G->getInitializer();
if(isa<ConstantAggregateZero>(I)) {
Init->SetType = ValSetTypeScalarSplat;
Type* I8 = Type::getInt8Ty(BB->invar->BB->getContext());
Constant* I8Z = Constant::getNullValue(I8);
Init->insert(ImprovedVal(I8Z));
}
else {
std::pair<ValSetType, ImprovedVal> InitIV = getValPB(I);
(*Init) = ImprovedValSetSingle(InitIV.second, InitIV.first);
}
}
else {
// Start off overdef, and known-older-than-specialisation.
Init->SetType = ValSetTypeOldOverdef;
}
}
else {
// All non-GVs initialise to an old value.
Init->SetType = ValSetTypeOldOverdef;
}
LocStore* LS = BB->getWritableStoreFor(AD.allocValue, 0, AD.storeSize, true);
release_assert(LS && "Non-writable location in initialiseStore?");
LS->store->dropReference();
LS->store = Init;
}
}
bool ObjCARCAPElim::runOnModule(Module &M) {
if (!EnableARCOpts)
return false;
// If nothing in the Module uses ARC, don't do anything.
if (!ModuleHasARC(M))
return false;
// Find the llvm.global_ctors variable, as the first step in
// identifying the global constructors. In theory, unnecessary autorelease
// pools could occur anywhere, but in practice it's pretty rare. Global
// ctors are a place where autorelease pools get inserted automatically,
// so it's pretty common for them to be unnecessary, and it's pretty
// profitable to eliminate them.
GlobalVariable *GV = M.getGlobalVariable("llvm.global_ctors");
if (!GV)
return false;
assert(GV->hasDefinitiveInitializer() &&
"llvm.global_ctors is uncooperative!");
bool Changed = false;
// Dig the constructor functions out of GV's initializer.
ConstantArray *Init = cast<ConstantArray>(GV->getInitializer());
for (User::op_iterator OI = Init->op_begin(), OE = Init->op_end();
OI != OE; ++OI) {
Value *Op = *OI;
// llvm.global_ctors is an array of three-field structs where the second
// members are constructor functions.
Function *F = dyn_cast<Function>(cast<ConstantStruct>(Op)->getOperand(1));
// If the user used a constructor function with the wrong signature and
// it got bitcasted or whatever, look the other way.
if (!F)
continue;
// Only look at function definitions.
if (F->isDeclaration())
continue;
// Only look at functions with one basic block.
if (std::next(F->begin()) != F->end())
continue;
// Ok, a single-block constructor function definition. Try to optimize it.
Changed |= OptimizeBB(F->begin());
}
return Changed;
}
// doInitialization - Initializes the vector of functions that have been
// annotated with the noinline attribute.
bool SimpleInliner::doInitialization(CallGraph &CG) {
CA.setTargetData(getAnalysisIfAvailable<TargetData>());
Module &M = CG.getModule();
for (Module::iterator I = M.begin(), E = M.end();
I != E; ++I)
if (!I->isDeclaration() && I->hasFnAttr(Attribute::NoInline))
NeverInline.insert(I);
// Get llvm.noinline
GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
if (GV == 0)
return false;
// Don't crash on invalid code
if (!GV->hasDefinitiveInitializer())
return false;
const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
if (InitList == 0)
return false;
// Iterate over each element and add to the NeverInline set
for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
// Get Source
const Constant *Elt = InitList->getOperand(i);
if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
if (CE->getOpcode() == Instruction::BitCast)
Elt = CE->getOperand(0);
// Insert into set of functions to never inline
if (const Function *F = dyn_cast<Function>(Elt))
NeverInline.insert(F);
}
return false;
}
/// Return the value that would be computed by a load from P after the stores
/// reflected by 'memory' have been performed. If we can't decide, return null.
Constant *Evaluator::ComputeLoadResult(Constant *P) {
// If this memory location has been recently stored, use the stored value: it
// is the most up-to-date.
DenseMap<Constant*, Constant*>::const_iterator I = MutatedMemory.find(P);
if (I != MutatedMemory.end()) return I->second;
// Access it.
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(P)) {
if (GV->hasDefinitiveInitializer())
return GV->getInitializer();
return nullptr;
}
// Handle a constantexpr getelementptr.
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(P))
if (CE->getOpcode() == Instruction::GetElementPtr &&
isa<GlobalVariable>(CE->getOperand(0))) {
GlobalVariable *GV = cast<GlobalVariable>(CE->getOperand(0));
if (GV->hasDefinitiveInitializer())
return ConstantFoldLoadThroughGEPConstantExpr(GV->getInitializer(), CE);
}
return nullptr; // don't know how to evaluate.
}
bool ConstantMerge::runOnModule(Module &M) {
TD = getAnalysisIfAvailable<TargetData>();
// Find all the globals that are marked "used". These cannot be merged.
SmallPtrSet<const GlobalValue*, 8> UsedGlobals;
FindUsedValues(M.getGlobalVariable("llvm.used"), UsedGlobals);
FindUsedValues(M.getGlobalVariable("llvm.compiler.used"), UsedGlobals);
// Map unique <constants, has-unknown-alignment> pairs to globals. We don't
// want to merge globals of unknown alignment with those of explicit
// alignment. If we have TargetData, we always know the alignment.
DenseMap<PointerIntPair<Constant*, 1, bool>, GlobalVariable*> CMap;
// Replacements - This vector contains a list of replacements to perform.
SmallVector<std::pair<GlobalVariable*, GlobalVariable*>, 32> Replacements;
bool MadeChange = false;
// Iterate constant merging while we are still making progress. Merging two
// constants together may allow us to merge other constants together if the
// second level constants have initializers which point to the globals that
// were just merged.
while (1) {
// First: Find the canonical constants others will be merged with.
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->hasLocalLinkage()) {
GV->eraseFromParent();
continue;
}
// Only process constants with initializers in the default address space.
if (!GV->isConstant() || !GV->hasDefinitiveInitializer() ||
GV->getType()->getAddressSpace() != 0 || GV->hasSection() ||
// Don't touch values marked with attribute(used).
UsedGlobals.count(GV))
continue;
// This transformation is legal for weak ODR globals in the sense it
// doesn't change semantics, but we really don't want to perform it
// anyway; it's likely to pessimize code generation, and some tools
// (like the Darwin linker in cases involving CFString) don't expect it.
if (GV->isWeakForLinker())
continue;
Constant *Init = GV->getInitializer();
// Check to see if the initializer is already known.
PointerIntPair<Constant*, 1, bool> Pair(Init, hasKnownAlignment(GV));
GlobalVariable *&Slot = CMap[Pair];
// If this is the first constant we find or if the old one is local,
// replace with the current one. If the current is externally visible
// it cannot be replace, but can be the canonical constant we merge with.
if (Slot == 0 || IsBetterCannonical(*GV, *Slot))
Slot = GV;
}
// Second: identify all globals that can be merged together, filling in
// the Replacements vector. We cannot do the replacement in this pass
// because doing so may cause initializers of other globals to be rewritten,
// invalidating the Constant* pointers in CMap.
for (Module::global_iterator GVI = M.global_begin(), E = M.global_end();
GVI != E; ) {
GlobalVariable *GV = GVI++;
// Only process constants with initializers in the default address space.
if (!GV->isConstant() || !GV->hasDefinitiveInitializer() ||
GV->getType()->getAddressSpace() != 0 || GV->hasSection() ||
// Don't touch values marked with attribute(used).
UsedGlobals.count(GV))
continue;
// We can only replace constant with local linkage.
if (!GV->hasLocalLinkage())
continue;
Constant *Init = GV->getInitializer();
// Check to see if the initializer is already known.
PointerIntPair<Constant*, 1, bool> Pair(Init, hasKnownAlignment(GV));
GlobalVariable *Slot = CMap[Pair];
if (!Slot || Slot == GV)
continue;
if (!Slot->hasUnnamedAddr() && !GV->hasUnnamedAddr())
continue;
if (!GV->hasUnnamedAddr())
Slot->setUnnamedAddr(false);
// Make all uses of the duplicate constant use the canonical version.
Replacements.push_back(std::make_pair(GV, Slot));
}
if (Replacements.empty())
return MadeChange;
CMap.clear();
// Now that we have figured out which replacements must be made, do them all
// now. This avoid invalidating the pointers in CMap, which are unneeded
// now.
for (unsigned i = 0, e = Replacements.size(); i != e; ++i) {
// Bump the alignment if necessary.
if (Replacements[i].first->getAlignment() ||
Replacements[i].second->getAlignment()) {
Replacements[i].second->setAlignment(std::max(
Replacements[i].first->getAlignment(),
Replacements[i].second->getAlignment()));
}
// Eliminate any uses of the dead global.
Replacements[i].first->replaceAllUsesWith(Replacements[i].second);
// Delete the global value from the module.
assert(Replacements[i].first->hasLocalLinkage() &&
"Refusing to delete an externally visible global variable.");
Replacements[i].first->eraseFromParent();
}
NumMerged += Replacements.size();
Replacements.clear();
}
}
bool ConstantMerge::runOnModule(Module &M) {
// Find all the globals that are marked "used". These cannot be merged.
SmallPtrSet<const GlobalValue*, 8> UsedGlobals;
FindUsedValues(M.getGlobalVariable("llvm.used"), UsedGlobals);
FindUsedValues(M.getGlobalVariable("llvm.compiler.used"), UsedGlobals);
// Map unique constant/section pairs to globals. We don't want to merge
// globals in different sections.
DenseMap<Constant*, GlobalVariable*> CMap;
// Replacements - This vector contains a list of replacements to perform.
SmallVector<std::pair<GlobalVariable*, GlobalVariable*>, 32> Replacements;
bool MadeChange = false;
// Iterate constant merging while we are still making progress. Merging two
// constants together may allow us to merge other constants together if the
// second level constants have initializers which point to the globals that
// were just merged.
while (1) {
// First pass: identify all globals that can be merged together, filling in
// the Replacements vector. We cannot do the replacement in this pass
// because doing so may cause initializers of other globals to be rewritten,
// invalidating the Constant* pointers in CMap.
//
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->hasLocalLinkage()) {
GV->eraseFromParent();
continue;
}
// Only process constants with initializers in the default addres space.
if (!GV->isConstant() ||!GV->hasDefinitiveInitializer() ||
GV->getType()->getAddressSpace() != 0 || !GV->getSection().empty() ||
// Don't touch values marked with attribute(used).
UsedGlobals.count(GV))
continue;
Constant *Init = GV->getInitializer();
// Check to see if the initializer is already known.
GlobalVariable *&Slot = CMap[Init];
if (Slot == 0) { // Nope, add it to the map.
Slot = GV;
} else if (GV->hasLocalLinkage()) { // Yup, this is a duplicate!
// Make all uses of the duplicate constant use the canonical version.
Replacements.push_back(std::make_pair(GV, Slot));
}
}
if (Replacements.empty())
return MadeChange;
CMap.clear();
// Now that we have figured out which replacements must be made, do them all
// now. This avoid invalidating the pointers in CMap, which are unneeded
// now.
for (unsigned i = 0, e = Replacements.size(); i != e; ++i) {
// Eliminate any uses of the dead global.
Replacements[i].first->replaceAllUsesWith(Replacements[i].second);
// Delete the global value from the module.
Replacements[i].first->eraseFromParent();
}
NumMerged += Replacements.size();
Replacements.clear();
}
}