STATISTIC(NumArgumentsPromoted , "Number of pointer arguments promoted");
STATISTIC(NumAggregatesPromoted, "Number of aggregate arguments promoted");
+STATISTIC(NumByValArgsPromoted , "Number of byval arguments promoted");
STATISTIC(NumArgumentsDead , "Number of dead pointer args eliminated");
namespace {
bool PromoteArguments(CallGraphNode *CGN);
bool isSafeToPromoteArgument(Argument *Arg, bool isByVal) const;
Function *DoPromotion(Function *F,
- SmallPtrSet<Argument*, 8> &ArgsToPromote);
+ SmallPtrSet<Argument*, 8> &ArgsToPromote,
+ SmallPtrSet<Argument*, 8> &ByValArgsToTransform);
};
char ArgPromotion::ID = 0;
// Check to see which arguments are promotable. If an argument is promotable,
// add it to ArgsToPromote.
SmallPtrSet<Argument*, 8> ArgsToPromote;
+ SmallPtrSet<Argument*, 8> ByValArgsToTransform;
for (unsigned i = 0; i != PointerArgs.size(); ++i) {
- bool isByVal = F->paramHasAttr(PointerArgs[i].second, ParamAttr::ByVal);
- if (isSafeToPromoteArgument(PointerArgs[i].first, isByVal))
- ArgsToPromote.insert(PointerArgs[i].first);
+ bool isByVal = F->paramHasAttr(PointerArgs[i].second+1, ParamAttr::ByVal);
+
+ // If this is a byval argument, and if the aggregate type is small, just
+ // pass the elements, which is always safe.
+ Argument *PtrArg = PointerArgs[i].first;
+ if (isByVal) {
+ const Type *AgTy = cast<PointerType>(PtrArg->getType())->getElementType();
+ if (const StructType *STy = dyn_cast<StructType>(AgTy))
+ if (STy->getNumElements() <= 3) {
+ // If all the elements are first class types, we can promote it.
+ bool AllSimple = true;
+ for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
+ if (!STy->getElementType(i)->isFirstClassType()) {
+ AllSimple = false;
+ break;
+ }
+
+ // Safe to transform, don't even bother trying to "promote" it.
+ // Passing the elements as a scalar will allow scalarrepl to hack on
+ // the new alloca we introduce.
+ if (AllSimple) {
+ ByValArgsToTransform.insert(PtrArg);
+ continue;
+ }
+ }
+ }
+
+ // Otherwise, see if we can promote the pointer to its value.
+ if (isSafeToPromoteArgument(PtrArg, isByVal))
+ ArgsToPromote.insert(PtrArg);
}
// No promotable pointer arguments.
- if (ArgsToPromote.empty()) return false;
+ if (ArgsToPromote.empty() && ByValArgsToTransform.empty()) return false;
- Function *NewF = DoPromotion(F, ArgsToPromote);
+ Function *NewF = DoPromotion(F, ArgsToPromote, ByValArgsToTransform);
// Update the call graph to know that the function has been transformed.
getAnalysis<CallGraph>().changeFunction(F, NewF);
/// arguments, and returns the new function. At this point, we know that it's
/// safe to do so.
Function *ArgPromotion::DoPromotion(Function *F,
- SmallPtrSet<Argument*, 8> &ArgsToPromote) {
+ SmallPtrSet<Argument*, 8> &ArgsToPromote,
+ SmallPtrSet<Argument*, 8> &ByValArgsToTransform) {
// Start by computing a new prototype for the function, which is the same as
// the old function, but has modified arguments.
unsigned index = 1;
for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E;
- ++I, ++index)
- if (!ArgsToPromote.count(I)) {
+ ++I, ++index) {
+ if (ByValArgsToTransform.count(I)) {
+ // Just add all the struct element types.
+ const Type *AgTy = cast<PointerType>(I->getType())->getElementType();
+ const StructType *STy = cast<StructType>(AgTy);
+ for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
+ Params.push_back(STy->getElementType(i));
+ ++NumByValArgsPromoted;
+ } else if (!ArgsToPromote.count(I)) {
Params.push_back(I->getType());
- if (PAL) {
- unsigned attrs = PAL->getParamAttrs(index);
- if (attrs)
- ParamAttrsVec.push_back(ParamAttrsWithIndex::get(Params.size(),
- attrs));
- }
+ if (unsigned attrs = PAL ? PAL->getParamAttrs(index) : 0)
+ ParamAttrsVec.push_back(ParamAttrsWithIndex::get(Params.size(), attrs));
} else if (I->use_empty()) {
++NumArgumentsDead;
} else {
else
++NumAggregatesPromoted;
}
+ }
const Type *RetTy = FTy->getReturnType();
CallSite::arg_iterator AI = CS.arg_begin();
for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end();
I != E; ++I, ++AI)
- if (!ArgsToPromote.count(I))
+ if (!ArgsToPromote.count(I) && !ByValArgsToTransform.count(I)) {
Args.push_back(*AI); // Unmodified argument
- else if (!I->use_empty()) {
+ } else if (ByValArgsToTransform.count(I)) {
+ // Emit a GEP and load for each element of the struct.
+ const Type *AgTy = cast<PointerType>(I->getType())->getElementType();
+ const StructType *STy = cast<StructType>(AgTy);
+ Value *Idxs[2] = { ConstantInt::get(Type::Int32Ty, 0), 0 };
+ for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
+ Idxs[1] = ConstantInt::get(Type::Int32Ty, i);
+ Value *Idx = new GetElementPtrInst(*AI, Idxs, Idxs+2,
+ (*AI)->getName()+"."+utostr(i),
+ Call);
+ // TODO: Tell AA about the new values?
+ Args.push_back(new LoadInst(Idx, Idx->getName()+".val", Call));
+ }
+ } else if (!I->use_empty()) {
// Non-dead argument: insert GEPs and loads as appropriate.
ScalarizeTable &ArgIndices = ScalarizedElements[I];
for (ScalarizeTable::iterator SI = ArgIndices.begin(),
// the new arguments, also transfering over the names as well.
//
for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(),
- I2 = NF->arg_begin(); I != E; ++I)
- if (!ArgsToPromote.count(I)) {
+ I2 = NF->arg_begin(); I != E; ++I) {
+ if (!ArgsToPromote.count(I) && !ByValArgsToTransform.count(I)) {
// If this is an unmodified argument, move the name and users over to the
// new version.
I->replaceAllUsesWith(I2);
I2->takeName(I);
AA.replaceWithNewValue(I, I2);
++I2;
- } else if (I->use_empty()) {
+ continue;
+ }
+
+ if (ByValArgsToTransform.count(I)) {
+ // In the callee, we create an alloca, and store each of the new incoming
+ // arguments into the alloca.
+ Instruction *InsertPt = NF->begin()->begin();
+
+ // Just add all the struct element types.
+ const Type *AgTy = cast<PointerType>(I->getType())->getElementType();
+ Value *TheAlloca = new AllocaInst(AgTy, 0, "", InsertPt);
+ const StructType *STy = cast<StructType>(AgTy);
+ Value *Idxs[2] = { ConstantInt::get(Type::Int32Ty, 0), 0 };
+
+ for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
+ Idxs[1] = ConstantInt::get(Type::Int32Ty, i);
+ Value *Idx = new GetElementPtrInst(TheAlloca, Idxs, Idxs+2,
+ TheAlloca->getName()+"."+utostr(i),
+ InsertPt);
+ I2->setName(I->getName()+"."+utostr(i));
+ new StoreInst(I2++, Idx, InsertPt);
+ }
+
+ // Anything that used the arg should now use the alloca.
+ I->replaceAllUsesWith(TheAlloca);
+ TheAlloca->takeName(I);
+ AA.replaceWithNewValue(I, TheAlloca);
+ continue;
+ }
+
+ if (I->use_empty()) {
AA.deleteValue(I);
- } else {
- // Otherwise, if we promoted this argument, then all users are load
- // instructions, and all loads should be using the new argument that we
- // added.
- ScalarizeTable &ArgIndices = ScalarizedElements[I];
-
- while (!I->use_empty()) {
- if (LoadInst *LI = dyn_cast<LoadInst>(I->use_back())) {
- assert(ArgIndices.begin()->empty() &&
- "Load element should sort to front!");
- I2->setName(I->getName()+".val");
- LI->replaceAllUsesWith(I2);
- AA.replaceWithNewValue(LI, I2);
- LI->eraseFromParent();
- DOUT << "*** Promoted load of argument '" << I->getName()
- << "' in function '" << F->getName() << "'\n";
- } else {
- GetElementPtrInst *GEP = cast<GetElementPtrInst>(I->use_back());
- std::vector<Value*> Operands(GEP->op_begin()+1, GEP->op_end());
-
- Function::arg_iterator TheArg = I2;
- for (ScalarizeTable::iterator It = ArgIndices.begin();
- *It != Operands; ++It, ++TheArg) {
- assert(It != ArgIndices.end() && "GEP not handled??");
- }
+ continue;
+ }
+
+ // Otherwise, if we promoted this argument, then all users are load
+ // instructions, and all loads should be using the new argument that we
+ // added.
+ ScalarizeTable &ArgIndices = ScalarizedElements[I];
+
+ while (!I->use_empty()) {
+ if (LoadInst *LI = dyn_cast<LoadInst>(I->use_back())) {
+ assert(ArgIndices.begin()->empty() &&
+ "Load element should sort to front!");
+ I2->setName(I->getName()+".val");
+ LI->replaceAllUsesWith(I2);
+ AA.replaceWithNewValue(LI, I2);
+ LI->eraseFromParent();
+ DOUT << "*** Promoted load of argument '" << I->getName()
+ << "' in function '" << F->getName() << "'\n";
+ } else {
+ GetElementPtrInst *GEP = cast<GetElementPtrInst>(I->use_back());
+ std::vector<Value*> Operands(GEP->op_begin()+1, GEP->op_end());
+
+ Function::arg_iterator TheArg = I2;
+ for (ScalarizeTable::iterator It = ArgIndices.begin();
+ *It != Operands; ++It, ++TheArg) {
+ assert(It != ArgIndices.end() && "GEP not handled??");
+ }
- std::string NewName = I->getName();
- for (unsigned i = 0, e = Operands.size(); i != e; ++i)
- if (ConstantInt *CI = dyn_cast<ConstantInt>(Operands[i]))
- NewName += "." + CI->getValue().toStringUnsigned(10);
- else
- NewName += ".x";
- TheArg->setName(NewName+".val");
-
- DOUT << "*** Promoted agg argument '" << TheArg->getName()
- << "' of function '" << F->getName() << "'\n";
-
- // All of the uses must be load instructions. Replace them all with
- // the argument specified by ArgNo.
- while (!GEP->use_empty()) {
- LoadInst *L = cast<LoadInst>(GEP->use_back());
- L->replaceAllUsesWith(TheArg);
- AA.replaceWithNewValue(L, TheArg);
- L->eraseFromParent();
- }
- AA.deleteValue(GEP);
- GEP->eraseFromParent();
+ std::string NewName = I->getName();
+ for (unsigned i = 0, e = Operands.size(); i != e; ++i)
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(Operands[i]))
+ NewName += "." + CI->getValue().toStringUnsigned(10);
+ else
+ NewName += ".x";
+ TheArg->setName(NewName+".val");
+
+ DOUT << "*** Promoted agg argument '" << TheArg->getName()
+ << "' of function '" << F->getName() << "'\n";
+
+ // All of the uses must be load instructions. Replace them all with
+ // the argument specified by ArgNo.
+ while (!GEP->use_empty()) {
+ LoadInst *L = cast<LoadInst>(GEP->use_back());
+ L->replaceAllUsesWith(TheArg);
+ AA.replaceWithNewValue(L, TheArg);
+ L->eraseFromParent();
}
+ AA.deleteValue(GEP);
+ GEP->eraseFromParent();
}
-
- // Increment I2 past all of the arguments added for this promoted pointer.
- for (unsigned i = 0, e = ArgIndices.size(); i != e; ++i)
- ++I2;
}
+ // Increment I2 past all of the arguments added for this promoted pointer.
+ for (unsigned i = 0, e = ArgIndices.size(); i != e; ++i)
+ ++I2;
+ }
+
// Notify the alias analysis implementation that we inserted a new argument.
if (ExtraArgHack)
AA.copyValue(Constant::getNullValue(Type::Int32Ty), NF->arg_begin());
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