#include "llvm/LLVMContext.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/CallGraph.h"
-#include "llvm/Target/TargetData.h"
#include "llvm/Support/CallSite.h"
-#include "llvm/Support/Compiler.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
namespace {
/// ArgPromotion - The 'by reference' to 'by value' argument promotion pass.
///
- struct VISIBILITY_HIDDEN ArgPromotion : public CallGraphSCCPass {
+ struct ArgPromotion : public CallGraphSCCPass {
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<AliasAnalysis>();
CallGraphSCCPass::getAnalysisUsage(AU);
}
- virtual bool runOnSCC(std::vector<CallGraphNode *> &SCC);
+ virtual bool runOnSCC(CallGraphSCC &SCC);
static char ID; // Pass identification, replacement for typeid
explicit ArgPromotion(unsigned maxElements = 3)
- : CallGraphSCCPass(&ID), maxElements(maxElements) {}
+ : CallGraphSCCPass(ID), maxElements(maxElements) {
+ initializeArgPromotionPass(*PassRegistry::getPassRegistry());
+ }
/// A vector used to hold the indices of a single GEP instruction
typedef std::vector<uint64_t> IndicesVector;
}
char ArgPromotion::ID = 0;
-static RegisterPass<ArgPromotion>
-X("argpromotion", "Promote 'by reference' arguments to scalars");
+INITIALIZE_PASS_BEGIN(ArgPromotion, "argpromotion",
+ "Promote 'by reference' arguments to scalars", false, false)
+INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_AG_DEPENDENCY(CallGraph)
+INITIALIZE_PASS_END(ArgPromotion, "argpromotion",
+ "Promote 'by reference' arguments to scalars", false, false)
Pass *llvm::createArgumentPromotionPass(unsigned maxElements) {
return new ArgPromotion(maxElements);
}
-bool ArgPromotion::runOnSCC(std::vector<CallGraphNode *> &SCC) {
+bool ArgPromotion::runOnSCC(CallGraphSCC &SCC) {
bool Changed = false, LocalChange;
do { // Iterate until we stop promoting from this SCC.
LocalChange = false;
// Attempt to promote arguments from all functions in this SCC.
- for (unsigned i = 0, e = SCC.size(); i != e; ++i)
- if (CallGraphNode *CGN = PromoteArguments(SCC[i])) {
+ for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
+ if (CallGraphNode *CGN = PromoteArguments(*I)) {
LocalChange = true;
- SCC[i] = CGN;
+ SCC.ReplaceNode(*I, CGN);
}
+ }
Changed |= LocalChange; // Remember that we changed something.
} while (LocalChange);
-
+
return Changed;
}
unsigned ArgNo = 0;
for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end();
I != E; ++I, ++ArgNo)
- if (isa<PointerType>(I->getType()))
+ if (I->getType()->isPointerTy())
PointerArgs.push_back(std::pair<Argument*, unsigned>(I, ArgNo));
if (PointerArgs.empty()) return 0;
const Type *AgTy = cast<PointerType>(PtrArg->getType())->getElementType();
if (const StructType *STy = dyn_cast<StructType>(AgTy)) {
if (maxElements > 0 && STy->getNumElements() > maxElements) {
- DEBUG(errs() << "argpromotion disable promoting argument '"
+ DEBUG(dbgs() << "argpromotion disable promoting argument '"
<< PtrArg->getName() << "' because it would require adding more"
<< " than " << maxElements << " arguments to the function.\n");
} else {
return DoPromotion(F, ArgsToPromote, ByValArgsToTransform);
}
-/// IsAlwaysValidPointer - Return true if the specified pointer is always legal
-/// to load.
-static bool IsAlwaysValidPointer(Value *V) {
- if (isa<AllocaInst>(V) || isa<GlobalVariable>(V)) return true;
- if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V))
- return IsAlwaysValidPointer(GEP->getOperand(0));
- if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
- if (CE->getOpcode() == Instruction::GetElementPtr)
- return IsAlwaysValidPointer(CE->getOperand(0));
-
- return false;
-}
-
/// AllCalleesPassInValidPointerForArgument - Return true if we can prove that
/// all callees pass in a valid pointer for the specified function argument.
static bool AllCalleesPassInValidPointerForArgument(Argument *Arg) {
// have direct callees.
for (Value::use_iterator UI = Callee->use_begin(), E = Callee->use_end();
UI != E; ++UI) {
- CallSite CS = CallSite::get(*UI);
- assert(CS.getInstruction() && "Should only have direct calls!");
+ CallSite CS(*UI);
+ assert(CS && "Should only have direct calls!");
- if (!IsAlwaysValidPointer(CS.getArgument(ArgNo)))
+ if (!CS.getArgument(ArgNo)->isDereferenceablePointer())
return false;
}
return true;
return Low != Set.end() && IsPrefix(*Low, Indices);
}
-/// Mark the given indices (ToMark) as safe in the the given set of indices
+/// Mark the given indices (ToMark) as safe in the given set of indices
/// (Safe). Marking safe usually means adding ToMark to Safe. However, if there
/// is already a prefix of Indices in Safe, Indices are implicitely marked safe
/// already. Furthermore, any indices that Indices is itself a prefix of, are
GEPIndicesSet ToPromote;
// If the pointer is always valid, any load with first index 0 is valid.
- if(isByVal || AllCalleesPassInValidPointerForArgument(Arg))
+ if (isByVal || AllCalleesPassInValidPointerForArgument(Arg))
SafeToUnconditionallyLoad.insert(IndicesVector(1, 0));
// First, iterate the entry block and mark loads of (geps of) arguments as
IndicesVector Operands;
for (Value::use_iterator UI = Arg->use_begin(), E = Arg->use_end();
UI != E; ++UI) {
+ User *U = *UI;
Operands.clear();
- if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) {
+ if (LoadInst *LI = dyn_cast<LoadInst>(U)) {
if (LI->isVolatile()) return false; // Don't hack volatile loads
Loads.push_back(LI);
// Direct loads are equivalent to a GEP with a zero index and then a load.
Operands.push_back(0);
- } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(*UI)) {
+ } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) {
if (GEP->use_empty()) {
// Dead GEP's cause trouble later. Just remove them if we run into
// them.
getAnalysis<AliasAnalysis>().deleteValue(GEP);
GEP->eraseFromParent();
- // TODO: This runs the above loop over and over again for dead GEPS
+ // TODO: This runs the above loop over and over again for dead GEPs
// Couldn't we just do increment the UI iterator earlier and erase the
// use?
return isSafeToPromoteArgument(Arg, isByVal);
// to do.
if (ToPromote.find(Operands) == ToPromote.end()) {
if (maxElements > 0 && ToPromote.size() == maxElements) {
- DEBUG(errs() << "argpromotion not promoting argument '"
+ DEBUG(dbgs() << "argpromotion not promoting argument '"
<< Arg->getName() << "' because it would require adding more "
<< "than " << maxElements << " arguments to the function.\n");
// We limit aggregate promotion to only promoting up to a fixed number
SmallPtrSet<BasicBlock*, 16> TranspBlocks;
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
- TargetData *TD = getAnalysisIfAvailable<TargetData>();
- if (!TD) return false; // Without TargetData, assume the worst.
for (unsigned i = 0, e = Loads.size(); i != e; ++i) {
// Check to see if the load is invalidated from the start of the block to
LoadInst *Load = Loads[i];
BasicBlock *BB = Load->getParent();
- const PointerType *LoadTy =
- cast<PointerType>(Load->getPointerOperand()->getType());
- unsigned LoadSize =(unsigned)TD->getTypeStoreSize(LoadTy->getElementType());
+ AliasAnalysis::Location Loc(Load->getPointerOperand(),
+ AA.getTypeStoreSize(Load->getType()),
+ Load->getMetadata(LLVMContext::MD_tbaa));
- if (AA.canInstructionRangeModify(BB->front(), *Load, Arg, LoadSize))
+ if (AA.canInstructionRangeModify(BB->front(), *Load, Loc))
return false; // Pointer is invalidated!
// Now check every path from the entry block to the load for transparency.
// To do this, we perform a depth first search on the inverse CFG from the
// loading block.
- for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
+ for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
+ BasicBlock *P = *PI;
for (idf_ext_iterator<BasicBlock*, SmallPtrSet<BasicBlock*, 16> >
- I = idf_ext_begin(*PI, TranspBlocks),
- E = idf_ext_end(*PI, TranspBlocks); I != E; ++I)
- if (AA.canBasicBlockModify(**I, Arg, LoadSize))
+ I = idf_ext_begin(P, TranspBlocks),
+ E = idf_ext_end(P, TranspBlocks); I != E; ++I)
+ if (AA.canBasicBlockModify(**I, Loc))
return false;
+ }
}
// If the path from the entry of the function to each load is free of
// Construct the new function type using the new arguments.
FunctionType *NFTy = FunctionType::get(RetTy, Params, FTy->isVarArg());
- // Create the new function body and insert it into the module...
+ // Create the new function body and insert it into the module.
Function *NF = Function::Create(NFTy, F->getLinkage(), F->getName());
NF->copyAttributesFrom(F);
+
+ DEBUG(dbgs() << "ARG PROMOTION: Promoting to:" << *NF << "\n"
+ << "From: " << *F);
+
// Recompute the parameter attributes list based on the new arguments for
// the function.
- NF->setAttributes(AttrListPtr::get(AttributesVec.begin(), AttributesVec.end()));
+ NF->setAttributes(AttrListPtr::get(AttributesVec.begin(),
+ AttributesVec.end()));
AttributesVec.clear();
F->getParent()->getFunctionList().insert(F, NF);
// Get a new callgraph node for NF.
CallGraphNode *NF_CGN = CG.getOrInsertFunction(NF);
-
// Loop over all of the callers of the function, transforming the call sites
// to pass in the loaded pointers.
//
SmallVector<Value*, 16> Args;
while (!F->use_empty()) {
- CallSite CS = CallSite::get(F->use_back());
+ CallSite CS(F->use_back());
+ assert(CS.getCalledFunction() == F);
Instruction *Call = CS.getInstruction();
const AttrListPtr &CallPAL = CS.getAttributes();
// Non-dead argument: insert GEPs and loads as appropriate.
ScalarizeTable &ArgIndices = ScalarizedElements[I];
// Store the Value* version of the indices in here, but declare it now
- // for reuse
+ // for reuse.
std::vector<Value*> Ops;
for (ScalarizeTable::iterator SI = ArgIndices.begin(),
E = ArgIndices.end(); SI != E; ++SI) {
IE = SI->end(); II != IE; ++II) {
// Use i32 to index structs, and i64 for others (pointers/arrays).
// This satisfies GEP constraints.
- const Type *IdxTy = (isa<StructType>(ElTy) ?
+ const Type *IdxTy = (ElTy->isStructTy() ?
Type::getInt32Ty(F->getContext()) :
Type::getInt64Ty(F->getContext()));
Ops.push_back(ConstantInt::get(IdxTy, *II));
- // Keep track of the type we're currently indexing
+ // Keep track of the type we're currently indexing.
ElTy = cast<CompositeType>(ElTy)->getTypeAtIndex(*II);
}
- // And create a GEP to extract those indices
+ // And create a GEP to extract those indices.
V = GetElementPtrInst::Create(V, Ops.begin(), Ops.end(),
V->getName()+".idx", Call);
Ops.clear();
AA.copyValue(OrigLoad->getOperand(0), V);
}
- Args.push_back(new LoadInst(V, V->getName()+".val", Call));
+ // Since we're replacing a load make sure we take the alignment
+ // of the previous load.
+ LoadInst *newLoad = new LoadInst(V, V->getName()+".val", Call);
+ newLoad->setAlignment(OrigLoad->getAlignment());
+ // Transfer the TBAA info too.
+ newLoad->setMetadata(LLVMContext::MD_tbaa,
+ OrigLoad->getMetadata(LLVMContext::MD_tbaa));
+ Args.push_back(newLoad);
AA.copyValue(OrigLoad, Args.back());
}
}
if (ExtraArgHack)
Args.push_back(Constant::getNullValue(Type::getInt32Ty(F->getContext())));
- // Push any varargs arguments on the list
+ // Push any varargs arguments on the list.
for (; AI != CS.arg_end(); ++AI, ++ArgIndex) {
Args.push_back(*AI);
if (Attributes Attrs = CallPAL.getParamAttributes(ArgIndex))
AA.replaceWithNewValue(Call, New);
// Update the callgraph to know that the callsite has been transformed.
- CG[Call->getParent()->getParent()]->replaceCallSite(Call, New, NF_CGN);
+ CallGraphNode *CalleeNode = CG[Call->getParent()->getParent()];
+ CalleeNode->replaceCallEdge(Call, New, NF_CGN);
if (!Call->use_empty()) {
Call->replaceAllUsesWith(New);
LI->replaceAllUsesWith(I2);
AA.replaceWithNewValue(LI, I2);
LI->eraseFromParent();
- DEBUG(errs() << "*** Promoted load of argument '" << I->getName()
+ DEBUG(dbgs() << "*** Promoted load of argument '" << I->getName()
<< "' in function '" << F->getName() << "'\n");
} else {
GetElementPtrInst *GEP = cast<GetElementPtrInst>(I->use_back());
NewName += ".val";
TheArg->setName(NewName);
- DEBUG(errs() << "*** Promoted agg argument '" << TheArg->getName()
+ DEBUG(dbgs() << "*** Promoted agg argument '" << TheArg->getName()
<< "' of function '" << NF->getName() << "'\n");
// All of the uses must be load instructions. Replace them all with
NF_CGN->stealCalledFunctionsFrom(CG[F]);
- // Now that the old function is dead, delete it.
- delete CG.removeFunctionFromModule(F);
+ // Now that the old function is dead, delete it. If there is a dangling
+ // reference to the CallgraphNode, just leave the dead function around for
+ // someone else to nuke.
+ CallGraphNode *CGN = CG[F];
+ if (CGN->getNumReferences() == 0)
+ delete CG.removeFunctionFromModule(CGN);
+ else
+ F->setLinkage(Function::ExternalLinkage);
return NF_CGN;
}
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