+//===- CloneFunction.cpp - Clone a function into another function ---------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the CloneFunctionInto interface, which is used as the
+// low-level function cloner. This is used by the CloneFunction and function
+// inliner to do the dirty work of copying the body of a function around.
+//
+//===----------------------------------------------------------------------===//
-// FIXME: document
-
-#include "llvm/Transforms/Utils/CloneFunction.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/GlobalVariable.h"
#include "llvm/Function.h"
-#include "llvm/BasicBlock.h"
-#include "llvm/Instruction.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Metadata.h"
+#include "llvm/Support/CFG.h"
+#include "llvm/Transforms/Utils/ValueMapper.h"
+#include "llvm/Analysis/ConstantFolding.h"
+#include "llvm/Analysis/DebugInfo.h"
+#include "llvm/ADT/SmallVector.h"
#include <map>
+using namespace llvm;
-// FIXME: This should be merged with FunctionInlining
-
-// RemapInstruction - Convert the instruction operands from referencing the
-// current values into those specified by ValueMap.
-//
-static inline void RemapInstruction(Instruction *I,
- std::map<const Value *, Value*> &ValueMap) {
- for (unsigned op = 0, E = I->getNumOperands(); op != E; ++op) {
- const Value *Op = I->getOperand(op);
- Value *V = ValueMap[Op];
- if (!V && (isa<GlobalValue>(Op) || isa<Constant>(Op)))
- continue; // Globals and constants don't get relocated
+// CloneBasicBlock - See comments in Cloning.h
+BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB,
+ DenseMap<const Value*, Value*> &ValueMap,
+ const char *NameSuffix, Function *F,
+ ClonedCodeInfo *CodeInfo) {
+ BasicBlock *NewBB = BasicBlock::Create(BB->getContext(), "", F);
+ if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
-#ifndef NDEBUG
- if (!V) {
- std::cerr << "Val = \n" << Op << "Addr = " << (void*)Op;
- std::cerr << "\nInst = " << I;
+ bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false;
+
+ // Loop over all instructions, and copy them over.
+ for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end();
+ II != IE; ++II) {
+ Instruction *NewInst = II->clone();
+ if (II->hasName())
+ NewInst->setName(II->getName()+NameSuffix);
+ NewBB->getInstList().push_back(NewInst);
+ ValueMap[II] = NewInst; // Add instruction map to value.
+
+ hasCalls |= (isa<CallInst>(II) && !isa<DbgInfoIntrinsic>(II));
+ if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
+ if (isa<ConstantInt>(AI->getArraySize()))
+ hasStaticAllocas = true;
+ else
+ hasDynamicAllocas = true;
}
-#endif
- assert(V && "Referenced value not in value map!");
- I->setOperand(op, V);
}
+
+ if (CodeInfo) {
+ CodeInfo->ContainsCalls |= hasCalls;
+ CodeInfo->ContainsUnwinds |= isa<UnwindInst>(BB->getTerminator());
+ CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
+ CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
+ BB != &BB->getParent()->getEntryBlock();
+ }
+ return NewBB;
}
// Clone OldFunc into NewFunc, transforming the old arguments into references to
// ArgMap values.
//
-void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
- const std::vector<Value*> &ArgMap) {
- assert(OldFunc->aempty() || !NewFunc->aempty() &&
- "Synthesization of arguments is not implemented yet!");
- assert(OldFunc->asize() == ArgMap.size() &&
- "Improper number of argument values to map specified!");
-
- // Keep a mapping between the original function's values and the new
- // duplicated code's values. This includes all of: Function arguments,
- // instruction values, constant pool entries, and basic blocks.
- //
- std::map<const Value *, Value*> ValueMap;
+void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
+ DenseMap<const Value*, Value*> &ValueMap,
+ SmallVectorImpl<ReturnInst*> &Returns,
+ const char *NameSuffix, ClonedCodeInfo *CodeInfo) {
+ assert(NameSuffix && "NameSuffix cannot be null!");
- // Add all of the function arguments to the mapping...
- unsigned i = 0;
- for (Function::const_aiterator I = OldFunc->abegin(), E = OldFunc->aend();
- I != E; ++I, ++i)
- ValueMap[I] = ArgMap[i];
+#ifndef NDEBUG
+ for (Function::const_arg_iterator I = OldFunc->arg_begin(),
+ E = OldFunc->arg_end(); I != E; ++I)
+ assert(ValueMap.count(I) && "No mapping from source argument specified!");
+#endif
+ // Clone any attributes.
+ if (NewFunc->arg_size() == OldFunc->arg_size())
+ NewFunc->copyAttributesFrom(OldFunc);
+ else {
+ //Some arguments were deleted with the ValueMap. Copy arguments one by one
+ for (Function::const_arg_iterator I = OldFunc->arg_begin(),
+ E = OldFunc->arg_end(); I != E; ++I)
+ if (Argument* Anew = dyn_cast<Argument>(ValueMap[I]))
+ Anew->addAttr( OldFunc->getAttributes()
+ .getParamAttributes(I->getArgNo() + 1));
+ NewFunc->setAttributes(NewFunc->getAttributes()
+ .addAttr(0, OldFunc->getAttributes()
+ .getRetAttributes()));
+ NewFunc->setAttributes(NewFunc->getAttributes()
+ .addAttr(~0, OldFunc->getAttributes()
+ .getFnAttributes()));
+
+ }
// Loop over all of the basic blocks in the function, cloning them as
- // appropriate.
+ // appropriate. Note that we save BE this way in order to handle cloning of
+ // recursive functions into themselves.
//
for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
BI != BE; ++BI) {
const BasicBlock &BB = *BI;
- assert(BB.getTerminator() && "BasicBlock doesn't have terminator!?!?");
-
- // Create a new basic block to copy instructions into!
- BasicBlock *CBB = new BasicBlock(BB.getName(), NewFunc);
+
+ // Create a new basic block and copy instructions into it!
+ BasicBlock *CBB = CloneBasicBlock(&BB, ValueMap, NameSuffix, NewFunc,
+ CodeInfo);
ValueMap[&BB] = CBB; // Add basic block mapping.
- // Loop over all instructions copying them over...
- for (BasicBlock::const_iterator II = BB.begin(), IE = BB.end();
- II != IE; ++II) {
- Instruction *NewInst = II->clone();
- NewInst->setName(II->getName()); // Name is not cloned...
- CBB->getInstList().push_back(NewInst);
- ValueMap[II] = NewInst; // Add instruction map to value.
- }
+ if (ReturnInst *RI = dyn_cast<ReturnInst>(CBB->getTerminator()))
+ Returns.push_back(RI);
}
- // Loop over all of the instructions in the function, fixing up operand
+ // Loop over all of the instructions in the function, fixing up operand
// references as we go. This uses ValueMap to do all the hard work.
//
- for (Function::const_iterator BB = OldFunc->begin(), BE = OldFunc->end();
- BB != BE; ++BB) {
- BasicBlock *NBB = cast<BasicBlock>(ValueMap[BB]);
-
+ for (Function::iterator BB = cast<BasicBlock>(ValueMap[OldFunc->begin()]),
+ BE = NewFunc->end(); BB != BE; ++BB)
// Loop over all instructions, fixing each one as we find it...
- for (BasicBlock::iterator II = NBB->begin(); II != NBB->end(); ++II)
+ for (BasicBlock::iterator II = BB->begin(); II != BB->end(); ++II)
RemapInstruction(II, ValueMap);
+}
+
+/// CloneFunction - Return a copy of the specified function, but without
+/// embedding the function into another module. Also, any references specified
+/// in the ValueMap are changed to refer to their mapped value instead of the
+/// original one. If any of the arguments to the function are in the ValueMap,
+/// the arguments are deleted from the resultant function. The ValueMap is
+/// updated to include mappings from all of the instructions and basicblocks in
+/// the function from their old to new values.
+///
+Function *llvm::CloneFunction(const Function *F,
+ DenseMap<const Value*, Value*> &ValueMap,
+ ClonedCodeInfo *CodeInfo) {
+ std::vector<const Type*> ArgTypes;
+
+ // The user might be deleting arguments to the function by specifying them in
+ // the ValueMap. If so, we need to not add the arguments to the arg ty vector
+ //
+ for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
+ I != E; ++I)
+ if (ValueMap.count(I) == 0) // Haven't mapped the argument to anything yet?
+ ArgTypes.push_back(I->getType());
+
+ // Create a new function type...
+ FunctionType *FTy = FunctionType::get(F->getFunctionType()->getReturnType(),
+ ArgTypes, F->getFunctionType()->isVarArg());
+
+ // Create the new function...
+ Function *NewF = Function::Create(FTy, F->getLinkage(), F->getName());
+
+ // Loop over the arguments, copying the names of the mapped arguments over...
+ Function::arg_iterator DestI = NewF->arg_begin();
+ for (Function::const_arg_iterator I = F->arg_begin(), E = F->arg_end();
+ I != E; ++I)
+ if (ValueMap.count(I) == 0) { // Is this argument preserved?
+ DestI->setName(I->getName()); // Copy the name over...
+ ValueMap[I] = DestI++; // Add mapping to ValueMap
+ }
+
+ SmallVector<ReturnInst*, 8> Returns; // Ignore returns cloned.
+ CloneFunctionInto(NewF, F, ValueMap, Returns, "", CodeInfo);
+ return NewF;
+}
+
+
+
+namespace {
+ /// PruningFunctionCloner - This class is a private class used to implement
+ /// the CloneAndPruneFunctionInto method.
+ struct PruningFunctionCloner {
+ Function *NewFunc;
+ const Function *OldFunc;
+ DenseMap<const Value*, Value*> &ValueMap;
+ SmallVectorImpl<ReturnInst*> &Returns;
+ const char *NameSuffix;
+ ClonedCodeInfo *CodeInfo;
+ const TargetData *TD;
+ public:
+ PruningFunctionCloner(Function *newFunc, const Function *oldFunc,
+ DenseMap<const Value*, Value*> &valueMap,
+ SmallVectorImpl<ReturnInst*> &returns,
+ const char *nameSuffix,
+ ClonedCodeInfo *codeInfo,
+ const TargetData *td)
+ : NewFunc(newFunc), OldFunc(oldFunc), ValueMap(valueMap), Returns(returns),
+ NameSuffix(nameSuffix), CodeInfo(codeInfo), TD(td) {
+ }
+
+ /// CloneBlock - The specified block is found to be reachable, clone it and
+ /// anything that it can reach.
+ void CloneBlock(const BasicBlock *BB,
+ std::vector<const BasicBlock*> &ToClone);
+
+ public:
+ /// ConstantFoldMappedInstruction - Constant fold the specified instruction,
+ /// mapping its operands through ValueMap if they are available.
+ Constant *ConstantFoldMappedInstruction(const Instruction *I);
+ };
+}
+
+/// CloneBlock - The specified block is found to be reachable, clone it and
+/// anything that it can reach.
+void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
+ std::vector<const BasicBlock*> &ToClone){
+ Value *&BBEntry = ValueMap[BB];
+
+ // Have we already cloned this block?
+ if (BBEntry) return;
+
+ // Nope, clone it now.
+ BasicBlock *NewBB;
+ BBEntry = NewBB = BasicBlock::Create(BB->getContext());
+ if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
+
+ bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false;
+
+ // Loop over all instructions, and copy them over, DCE'ing as we go. This
+ // loop doesn't include the terminator.
+ for (BasicBlock::const_iterator II = BB->begin(), IE = --BB->end();
+ II != IE; ++II) {
+ // If this instruction constant folds, don't bother cloning the instruction,
+ // instead, just add the constant to the value map.
+ if (Constant *C = ConstantFoldMappedInstruction(II)) {
+ ValueMap[II] = C;
+ continue;
+ }
+
+ Instruction *NewInst = II->clone();
+ if (II->hasName())
+ NewInst->setName(II->getName()+NameSuffix);
+ NewBB->getInstList().push_back(NewInst);
+ ValueMap[II] = NewInst; // Add instruction map to value.
+
+ hasCalls |= (isa<CallInst>(II) && !isa<DbgInfoIntrinsic>(II));
+ if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
+ if (isa<ConstantInt>(AI->getArraySize()))
+ hasStaticAllocas = true;
+ else
+ hasDynamicAllocas = true;
+ }
+ }
+
+ // Finally, clone over the terminator.
+ const TerminatorInst *OldTI = BB->getTerminator();
+ bool TerminatorDone = false;
+ if (const BranchInst *BI = dyn_cast<BranchInst>(OldTI)) {
+ if (BI->isConditional()) {
+ // If the condition was a known constant in the callee...
+ ConstantInt *Cond = dyn_cast<ConstantInt>(BI->getCondition());
+ // Or is a known constant in the caller...
+ if (Cond == 0)
+ Cond = dyn_cast_or_null<ConstantInt>(ValueMap[BI->getCondition()]);
+
+ // Constant fold to uncond branch!
+ if (Cond) {
+ BasicBlock *Dest = BI->getSuccessor(!Cond->getZExtValue());
+ ValueMap[OldTI] = BranchInst::Create(Dest, NewBB);
+ ToClone.push_back(Dest);
+ TerminatorDone = true;
+ }
+ }
+ } else if (const SwitchInst *SI = dyn_cast<SwitchInst>(OldTI)) {
+ // If switching on a value known constant in the caller.
+ ConstantInt *Cond = dyn_cast<ConstantInt>(SI->getCondition());
+ if (Cond == 0) // Or known constant after constant prop in the callee...
+ Cond = dyn_cast_or_null<ConstantInt>(ValueMap[SI->getCondition()]);
+ if (Cond) { // Constant fold to uncond branch!
+ BasicBlock *Dest = SI->getSuccessor(SI->findCaseValue(Cond));
+ ValueMap[OldTI] = BranchInst::Create(Dest, NewBB);
+ ToClone.push_back(Dest);
+ TerminatorDone = true;
+ }
+ }
+
+ if (!TerminatorDone) {
+ Instruction *NewInst = OldTI->clone();
+ if (OldTI->hasName())
+ NewInst->setName(OldTI->getName()+NameSuffix);
+ NewBB->getInstList().push_back(NewInst);
+ ValueMap[OldTI] = NewInst; // Add instruction map to value.
+
+ // Recursively clone any reachable successor blocks.
+ const TerminatorInst *TI = BB->getTerminator();
+ for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
+ ToClone.push_back(TI->getSuccessor(i));
+ }
+
+ if (CodeInfo) {
+ CodeInfo->ContainsCalls |= hasCalls;
+ CodeInfo->ContainsUnwinds |= isa<UnwindInst>(OldTI);
+ CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
+ CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
+ BB != &BB->getParent()->front();
+ }
+
+ if (ReturnInst *RI = dyn_cast<ReturnInst>(NewBB->getTerminator()))
+ Returns.push_back(RI);
+}
+
+/// ConstantFoldMappedInstruction - Constant fold the specified instruction,
+/// mapping its operands through ValueMap if they are available.
+Constant *PruningFunctionCloner::
+ConstantFoldMappedInstruction(const Instruction *I) {
+ SmallVector<Constant*, 8> Ops;
+ for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
+ if (Constant *Op = dyn_cast_or_null<Constant>(MapValue(I->getOperand(i),
+ ValueMap)))
+ Ops.push_back(Op);
+ else
+ return 0; // All operands not constant!
+
+ if (const CmpInst *CI = dyn_cast<CmpInst>(I))
+ return ConstantFoldCompareInstOperands(CI->getPredicate(), Ops[0], Ops[1],
+ TD);
+
+ if (const LoadInst *LI = dyn_cast<LoadInst>(I))
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0]))
+ if (!LI->isVolatile() && CE->getOpcode() == Instruction::GetElementPtr)
+ if (GlobalVariable *GV = dyn_cast<GlobalVariable>(CE->getOperand(0)))
+ if (GV->isConstant() && GV->hasDefinitiveInitializer())
+ return ConstantFoldLoadThroughGEPConstantExpr(GV->getInitializer(),
+ CE);
+
+ return ConstantFoldInstOperands(I->getOpcode(), I->getType(), &Ops[0],
+ Ops.size(), TD);
+}
+
+static MDNode *UpdateInlinedAtInfo(MDNode *InsnMD, MDNode *TheCallMD) {
+ DILocation ILoc(InsnMD);
+ if (ILoc.isNull()) return InsnMD;
+
+ DILocation CallLoc(TheCallMD);
+ if (CallLoc.isNull()) return InsnMD;
+
+ DILocation OrigLocation = ILoc.getOrigLocation();
+ MDNode *NewLoc = TheCallMD;
+ if (!OrigLocation.isNull())
+ NewLoc = UpdateInlinedAtInfo(OrigLocation.getNode(), TheCallMD);
+
+ Value *MDVs[] = {
+ InsnMD->getOperand(0), // Line
+ InsnMD->getOperand(1), // Col
+ InsnMD->getOperand(2), // Scope
+ NewLoc
+ };
+ return MDNode::get(InsnMD->getContext(), MDVs, 4);
+}
+
+/// CloneAndPruneFunctionInto - This works exactly like CloneFunctionInto,
+/// except that it does some simple constant prop and DCE on the fly. The
+/// effect of this is to copy significantly less code in cases where (for
+/// example) a function call with constant arguments is inlined, and those
+/// constant arguments cause a significant amount of code in the callee to be
+/// dead. Since this doesn't produce an exact copy of the input, it can't be
+/// used for things like CloneFunction or CloneModule.
+void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
+ DenseMap<const Value*, Value*> &ValueMap,
+ SmallVectorImpl<ReturnInst*> &Returns,
+ const char *NameSuffix,
+ ClonedCodeInfo *CodeInfo,
+ const TargetData *TD,
+ Instruction *TheCall) {
+ assert(NameSuffix && "NameSuffix cannot be null!");
+
+#ifndef NDEBUG
+ for (Function::const_arg_iterator II = OldFunc->arg_begin(),
+ E = OldFunc->arg_end(); II != E; ++II)
+ assert(ValueMap.count(II) && "No mapping from source argument specified!");
+#endif
+
+ PruningFunctionCloner PFC(NewFunc, OldFunc, ValueMap, Returns,
+ NameSuffix, CodeInfo, TD);
+
+ // Clone the entry block, and anything recursively reachable from it.
+ std::vector<const BasicBlock*> CloneWorklist;
+ CloneWorklist.push_back(&OldFunc->getEntryBlock());
+ while (!CloneWorklist.empty()) {
+ const BasicBlock *BB = CloneWorklist.back();
+ CloneWorklist.pop_back();
+ PFC.CloneBlock(BB, CloneWorklist);
+ }
+
+ // Loop over all of the basic blocks in the old function. If the block was
+ // reachable, we have cloned it and the old block is now in the value map:
+ // insert it into the new function in the right order. If not, ignore it.
+ //
+ // Defer PHI resolution until rest of function is resolved.
+ SmallVector<const PHINode*, 16> PHIToResolve;
+ for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
+ BI != BE; ++BI) {
+ BasicBlock *NewBB = cast_or_null<BasicBlock>(ValueMap[BI]);
+ if (NewBB == 0) continue; // Dead block.
+
+ // Add the new block to the new function.
+ NewFunc->getBasicBlockList().push_back(NewBB);
+
+ // Loop over all of the instructions in the block, fixing up operand
+ // references as we go. This uses ValueMap to do all the hard work.
+ //
+ BasicBlock::iterator I = NewBB->begin();
+
+ unsigned DbgKind = OldFunc->getContext().getMDKindID("dbg");
+ MDNode *TheCallMD = NULL;
+ if (TheCall && TheCall->hasMetadata())
+ TheCallMD = TheCall->getMetadata(DbgKind);
+
+ // Handle PHI nodes specially, as we have to remove references to dead
+ // blocks.
+ if (PHINode *PN = dyn_cast<PHINode>(I)) {
+ // Skip over all PHI nodes, remembering them for later.
+ BasicBlock::const_iterator OldI = BI->begin();
+ for (; (PN = dyn_cast<PHINode>(I)); ++I, ++OldI) {
+ if (I->hasMetadata()) {
+ if (TheCallMD) {
+ if (MDNode *IMD = I->getMetadata(DbgKind)) {
+ MDNode *NewMD = UpdateInlinedAtInfo(IMD, TheCallMD);
+ I->setMetadata(DbgKind, NewMD);
+ }
+ } else {
+ // The cloned instruction has dbg info but the call instruction
+ // does not have dbg info. Remove dbg info from cloned instruction.
+ I->setMetadata(DbgKind, 0);
+ }
+ }
+ PHIToResolve.push_back(cast<PHINode>(OldI));
+ }
+ }
+
+ // FIXME:
+ // FIXME:
+ // FIXME: Unclone all this metadata stuff.
+ // FIXME:
+ // FIXME:
+
+ // Otherwise, remap the rest of the instructions normally.
+ for (; I != NewBB->end(); ++I) {
+ if (I->hasMetadata()) {
+ if (TheCallMD) {
+ if (MDNode *IMD = I->getMetadata(DbgKind)) {
+ MDNode *NewMD = UpdateInlinedAtInfo(IMD, TheCallMD);
+ I->setMetadata(DbgKind, NewMD);
+ }
+ } else {
+ // The cloned instruction has dbg info but the call instruction
+ // does not have dbg info. Remove dbg info from cloned instruction.
+ I->setMetadata(DbgKind, 0);
+ }
+ }
+ RemapInstruction(I, ValueMap);
+ }
+ }
+
+ // Defer PHI resolution until rest of function is resolved, PHI resolution
+ // requires the CFG to be up-to-date.
+ for (unsigned phino = 0, e = PHIToResolve.size(); phino != e; ) {
+ const PHINode *OPN = PHIToResolve[phino];
+ unsigned NumPreds = OPN->getNumIncomingValues();
+ const BasicBlock *OldBB = OPN->getParent();
+ BasicBlock *NewBB = cast<BasicBlock>(ValueMap[OldBB]);
+
+ // Map operands for blocks that are live and remove operands for blocks
+ // that are dead.
+ for (; phino != PHIToResolve.size() &&
+ PHIToResolve[phino]->getParent() == OldBB; ++phino) {
+ OPN = PHIToResolve[phino];
+ PHINode *PN = cast<PHINode>(ValueMap[OPN]);
+ for (unsigned pred = 0, e = NumPreds; pred != e; ++pred) {
+ if (BasicBlock *MappedBlock =
+ cast_or_null<BasicBlock>(ValueMap[PN->getIncomingBlock(pred)])) {
+ Value *InVal = MapValue(PN->getIncomingValue(pred),
+ ValueMap);
+ assert(InVal && "Unknown input value?");
+ PN->setIncomingValue(pred, InVal);
+ PN->setIncomingBlock(pred, MappedBlock);
+ } else {
+ PN->removeIncomingValue(pred, false);
+ --pred, --e; // Revisit the next entry.
+ }
+ }
+ }
+
+ // The loop above has removed PHI entries for those blocks that are dead
+ // and has updated others. However, if a block is live (i.e. copied over)
+ // but its terminator has been changed to not go to this block, then our
+ // phi nodes will have invalid entries. Update the PHI nodes in this
+ // case.
+ PHINode *PN = cast<PHINode>(NewBB->begin());
+ NumPreds = std::distance(pred_begin(NewBB), pred_end(NewBB));
+ if (NumPreds != PN->getNumIncomingValues()) {
+ assert(NumPreds < PN->getNumIncomingValues());
+ // Count how many times each predecessor comes to this block.
+ std::map<BasicBlock*, unsigned> PredCount;
+ for (pred_iterator PI = pred_begin(NewBB), E = pred_end(NewBB);
+ PI != E; ++PI)
+ --PredCount[*PI];
+
+ // Figure out how many entries to remove from each PHI.
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+ ++PredCount[PN->getIncomingBlock(i)];
+
+ // At this point, the excess predecessor entries are positive in the
+ // map. Loop over all of the PHIs and remove excess predecessor
+ // entries.
+ BasicBlock::iterator I = NewBB->begin();
+ for (; (PN = dyn_cast<PHINode>(I)); ++I) {
+ for (std::map<BasicBlock*, unsigned>::iterator PCI =PredCount.begin(),
+ E = PredCount.end(); PCI != E; ++PCI) {
+ BasicBlock *Pred = PCI->first;
+ for (unsigned NumToRemove = PCI->second; NumToRemove; --NumToRemove)
+ PN->removeIncomingValue(Pred, false);
+ }
+ }
+ }
+
+ // If the loops above have made these phi nodes have 0 or 1 operand,
+ // replace them with undef or the input value. We must do this for
+ // correctness, because 0-operand phis are not valid.
+ PN = cast<PHINode>(NewBB->begin());
+ if (PN->getNumIncomingValues() == 0) {
+ BasicBlock::iterator I = NewBB->begin();
+ BasicBlock::const_iterator OldI = OldBB->begin();
+ while ((PN = dyn_cast<PHINode>(I++))) {
+ Value *NV = UndefValue::get(PN->getType());
+ PN->replaceAllUsesWith(NV);
+ assert(ValueMap[OldI] == PN && "ValueMap mismatch");
+ ValueMap[OldI] = NV;
+ PN->eraseFromParent();
+ ++OldI;
+ }
+ }
+ // NOTE: We cannot eliminate single entry phi nodes here, because of
+ // ValueMap. Single entry phi nodes can have multiple ValueMap entries
+ // pointing at them. Thus, deleting one would require scanning the ValueMap
+ // to update any entries in it that would require that. This would be
+ // really slow.
+ }
+
+ // Now that the inlined function body has been fully constructed, go through
+ // and zap unconditional fall-through branches. This happen all the time when
+ // specializing code: code specialization turns conditional branches into
+ // uncond branches, and this code folds them.
+ Function::iterator I = cast<BasicBlock>(ValueMap[&OldFunc->getEntryBlock()]);
+ while (I != NewFunc->end()) {
+ BranchInst *BI = dyn_cast<BranchInst>(I->getTerminator());
+ if (!BI || BI->isConditional()) { ++I; continue; }
+
+ // Note that we can't eliminate uncond branches if the destination has
+ // single-entry PHI nodes. Eliminating the single-entry phi nodes would
+ // require scanning the ValueMap to update any entries that point to the phi
+ // node.
+ BasicBlock *Dest = BI->getSuccessor(0);
+ if (!Dest->getSinglePredecessor() || isa<PHINode>(Dest->begin())) {
+ ++I; continue;
+ }
+
+ // We know all single-entry PHI nodes in the inlined function have been
+ // removed, so we just need to splice the blocks.
+ BI->eraseFromParent();
+
+ // Move all the instructions in the succ to the pred.
+ I->getInstList().splice(I->end(), Dest->getInstList());
+
+ // Make all PHI nodes that referred to Dest now refer to I as their source.
+ Dest->replaceAllUsesWith(I);
+
+ // Remove the dest block.
+ Dest->eraseFromParent();
+
+ // Do not increment I, iteratively merge all things this block branches to.
}
}
projects / oota-llvm.git / blobdiff