forked from OSchip/llvm-project
785 lines
32 KiB
C++
785 lines
32 KiB
C++
//===- 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.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Transforms/Utils/Cloning.h"
|
|
#include "llvm/ADT/SmallVector.h"
|
|
#include "llvm/Analysis/ConstantFolding.h"
|
|
#include "llvm/Analysis/InstructionSimplify.h"
|
|
#include "llvm/Analysis/LoopInfo.h"
|
|
#include "llvm/IR/CFG.h"
|
|
#include "llvm/IR/Constants.h"
|
|
#include "llvm/IR/DebugInfo.h"
|
|
#include "llvm/IR/DerivedTypes.h"
|
|
#include "llvm/IR/Function.h"
|
|
#include "llvm/IR/GlobalVariable.h"
|
|
#include "llvm/IR/Instructions.h"
|
|
#include "llvm/IR/IntrinsicInst.h"
|
|
#include "llvm/IR/LLVMContext.h"
|
|
#include "llvm/IR/Metadata.h"
|
|
#include "llvm/IR/Module.h"
|
|
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
|
|
#include "llvm/Transforms/Utils/Local.h"
|
|
#include "llvm/Transforms/Utils/ValueMapper.h"
|
|
#include <map>
|
|
using namespace llvm;
|
|
|
|
/// See comments in Cloning.h.
|
|
BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB,
|
|
ValueToValueMapTy &VMap,
|
|
const Twine &NameSuffix, Function *F,
|
|
ClonedCodeInfo *CodeInfo) {
|
|
BasicBlock *NewBB = BasicBlock::Create(BB->getContext(), "", F);
|
|
if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
|
|
|
|
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);
|
|
VMap[&*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;
|
|
}
|
|
}
|
|
|
|
if (CodeInfo) {
|
|
CodeInfo->ContainsCalls |= hasCalls;
|
|
CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
|
|
CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
|
|
BB != &BB->getParent()->getEntryBlock();
|
|
}
|
|
return NewBB;
|
|
}
|
|
|
|
// Clone OldFunc into NewFunc, transforming the old arguments into references to
|
|
// VMap values.
|
|
//
|
|
void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
|
|
ValueToValueMapTy &VMap,
|
|
bool ModuleLevelChanges,
|
|
SmallVectorImpl<ReturnInst*> &Returns,
|
|
const char *NameSuffix, ClonedCodeInfo *CodeInfo,
|
|
ValueMapTypeRemapper *TypeMapper,
|
|
ValueMaterializer *Materializer) {
|
|
assert(NameSuffix && "NameSuffix cannot be null!");
|
|
|
|
#ifndef NDEBUG
|
|
for (const Argument &I : OldFunc->args())
|
|
assert(VMap.count(&I) && "No mapping from source argument specified!");
|
|
#endif
|
|
|
|
// Copy all attributes other than those stored in the AttributeSet. We need
|
|
// to remap the parameter indices of the AttributeSet.
|
|
AttributeSet NewAttrs = NewFunc->getAttributes();
|
|
NewFunc->copyAttributesFrom(OldFunc);
|
|
NewFunc->setAttributes(NewAttrs);
|
|
|
|
AttributeSet OldAttrs = OldFunc->getAttributes();
|
|
// Clone any argument attributes that are present in the VMap.
|
|
for (const Argument &OldArg : OldFunc->args())
|
|
if (Argument *NewArg = dyn_cast<Argument>(VMap[&OldArg])) {
|
|
AttributeSet attrs =
|
|
OldAttrs.getParamAttributes(OldArg.getArgNo() + 1);
|
|
if (attrs.getNumSlots() > 0)
|
|
NewArg->addAttr(attrs);
|
|
}
|
|
|
|
NewFunc->setAttributes(
|
|
NewFunc->getAttributes()
|
|
.addAttributes(NewFunc->getContext(), AttributeSet::ReturnIndex,
|
|
OldAttrs.getRetAttributes())
|
|
.addAttributes(NewFunc->getContext(), AttributeSet::FunctionIndex,
|
|
OldAttrs.getFnAttributes()));
|
|
|
|
// Loop over all of the basic blocks in the function, cloning them as
|
|
// 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;
|
|
|
|
// Create a new basic block and copy instructions into it!
|
|
BasicBlock *CBB = CloneBasicBlock(&BB, VMap, NameSuffix, NewFunc, CodeInfo);
|
|
|
|
// Add basic block mapping.
|
|
VMap[&BB] = CBB;
|
|
|
|
// It is only legal to clone a function if a block address within that
|
|
// function is never referenced outside of the function. Given that, we
|
|
// want to map block addresses from the old function to block addresses in
|
|
// the clone. (This is different from the generic ValueMapper
|
|
// implementation, which generates an invalid blockaddress when
|
|
// cloning a function.)
|
|
if (BB.hasAddressTaken()) {
|
|
Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
|
|
const_cast<BasicBlock*>(&BB));
|
|
VMap[OldBBAddr] = BlockAddress::get(NewFunc, CBB);
|
|
}
|
|
|
|
// Note return instructions for the caller.
|
|
if (ReturnInst *RI = dyn_cast<ReturnInst>(CBB->getTerminator()))
|
|
Returns.push_back(RI);
|
|
}
|
|
|
|
// Loop over all of the instructions in the function, fixing up operand
|
|
// references as we go. This uses VMap to do all the hard work.
|
|
for (Function::iterator BB =
|
|
cast<BasicBlock>(VMap[&OldFunc->front()])->getIterator(),
|
|
BE = NewFunc->end();
|
|
BB != BE; ++BB)
|
|
// Loop over all instructions, fixing each one as we find it...
|
|
for (Instruction &II : *BB)
|
|
RemapInstruction(&II, VMap,
|
|
ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
|
|
TypeMapper, Materializer);
|
|
}
|
|
|
|
// Find the MDNode which corresponds to the subprogram data that described F.
|
|
static DISubprogram *FindSubprogram(const Function *F,
|
|
DebugInfoFinder &Finder) {
|
|
for (DISubprogram *Subprogram : Finder.subprograms()) {
|
|
if (Subprogram->describes(F))
|
|
return Subprogram;
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
// Add an operand to an existing MDNode. The new operand will be added at the
|
|
// back of the operand list.
|
|
static void AddOperand(DICompileUnit *CU, DISubprogramArray SPs,
|
|
Metadata *NewSP) {
|
|
SmallVector<Metadata *, 16> NewSPs;
|
|
NewSPs.reserve(SPs.size() + 1);
|
|
for (auto *SP : SPs)
|
|
NewSPs.push_back(SP);
|
|
NewSPs.push_back(NewSP);
|
|
CU->replaceSubprograms(MDTuple::get(CU->getContext(), NewSPs));
|
|
}
|
|
|
|
// Clone the module-level debug info associated with OldFunc. The cloned data
|
|
// will point to NewFunc instead.
|
|
static void CloneDebugInfoMetadata(Function *NewFunc, const Function *OldFunc,
|
|
ValueToValueMapTy &VMap) {
|
|
DebugInfoFinder Finder;
|
|
Finder.processModule(*OldFunc->getParent());
|
|
|
|
const DISubprogram *OldSubprogramMDNode = FindSubprogram(OldFunc, Finder);
|
|
if (!OldSubprogramMDNode) return;
|
|
|
|
auto *NewSubprogram =
|
|
cast<DISubprogram>(MapMetadata(OldSubprogramMDNode, VMap));
|
|
NewFunc->setSubprogram(NewSubprogram);
|
|
|
|
for (auto *CU : Finder.compile_units()) {
|
|
auto Subprograms = CU->getSubprograms();
|
|
// If the compile unit's function list contains the old function, it should
|
|
// also contain the new one.
|
|
for (auto *SP : Subprograms) {
|
|
if (SP == OldSubprogramMDNode) {
|
|
AddOperand(CU, Subprograms, NewSubprogram);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Return a copy of the specified function, but without
|
|
/// embedding the function into another module. Also, any references specified
|
|
/// in the VMap are changed to refer to their mapped value instead of the
|
|
/// original one. If any of the arguments to the function are in the VMap,
|
|
/// the arguments are deleted from the resultant function. The VMap 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, ValueToValueMapTy &VMap,
|
|
bool ModuleLevelChanges,
|
|
ClonedCodeInfo *CodeInfo) {
|
|
std::vector<Type*> ArgTypes;
|
|
|
|
// The user might be deleting arguments to the function by specifying them in
|
|
// the VMap. If so, we need to not add the arguments to the arg ty vector
|
|
//
|
|
for (const Argument &I : F->args())
|
|
if (VMap.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 (const Argument & I : F->args())
|
|
if (VMap.count(&I) == 0) { // Is this argument preserved?
|
|
DestI->setName(I.getName()); // Copy the name over...
|
|
VMap[&I] = &*DestI++; // Add mapping to VMap
|
|
}
|
|
|
|
if (ModuleLevelChanges)
|
|
CloneDebugInfoMetadata(NewF, F, VMap);
|
|
|
|
SmallVector<ReturnInst*, 8> Returns; // Ignore returns cloned.
|
|
CloneFunctionInto(NewF, F, VMap, ModuleLevelChanges, Returns, "", CodeInfo);
|
|
return NewF;
|
|
}
|
|
|
|
|
|
|
|
namespace {
|
|
/// This is a private class used to implement CloneAndPruneFunctionInto.
|
|
struct PruningFunctionCloner {
|
|
Function *NewFunc;
|
|
const Function *OldFunc;
|
|
ValueToValueMapTy &VMap;
|
|
bool ModuleLevelChanges;
|
|
const char *NameSuffix;
|
|
ClonedCodeInfo *CodeInfo;
|
|
CloningDirector *Director;
|
|
ValueMapTypeRemapper *TypeMapper;
|
|
ValueMaterializer *Materializer;
|
|
|
|
public:
|
|
PruningFunctionCloner(Function *newFunc, const Function *oldFunc,
|
|
ValueToValueMapTy &valueMap, bool moduleLevelChanges,
|
|
const char *nameSuffix, ClonedCodeInfo *codeInfo,
|
|
CloningDirector *Director)
|
|
: NewFunc(newFunc), OldFunc(oldFunc), VMap(valueMap),
|
|
ModuleLevelChanges(moduleLevelChanges), NameSuffix(nameSuffix),
|
|
CodeInfo(codeInfo), Director(Director) {
|
|
// These are optional components. The Director may return null.
|
|
if (Director) {
|
|
TypeMapper = Director->getTypeRemapper();
|
|
Materializer = Director->getValueMaterializer();
|
|
} else {
|
|
TypeMapper = nullptr;
|
|
Materializer = nullptr;
|
|
}
|
|
}
|
|
|
|
/// The specified block is found to be reachable, clone it and
|
|
/// anything that it can reach.
|
|
void CloneBlock(const BasicBlock *BB,
|
|
BasicBlock::const_iterator StartingInst,
|
|
std::vector<const BasicBlock*> &ToClone);
|
|
};
|
|
}
|
|
|
|
/// The specified block is found to be reachable, clone it and
|
|
/// anything that it can reach.
|
|
void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
|
|
BasicBlock::const_iterator StartingInst,
|
|
std::vector<const BasicBlock*> &ToClone){
|
|
WeakVH &BBEntry = VMap[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);
|
|
|
|
// It is only legal to clone a function if a block address within that
|
|
// function is never referenced outside of the function. Given that, we
|
|
// want to map block addresses from the old function to block addresses in
|
|
// the clone. (This is different from the generic ValueMapper
|
|
// implementation, which generates an invalid blockaddress when
|
|
// cloning a function.)
|
|
//
|
|
// Note that we don't need to fix the mapping for unreachable blocks;
|
|
// the default mapping there is safe.
|
|
if (BB->hasAddressTaken()) {
|
|
Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
|
|
const_cast<BasicBlock*>(BB));
|
|
VMap[OldBBAddr] = BlockAddress::get(NewFunc, NewBB);
|
|
}
|
|
|
|
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 = StartingInst, IE = --BB->end();
|
|
II != IE; ++II) {
|
|
// If the "Director" remaps the instruction, don't clone it.
|
|
if (Director) {
|
|
CloningDirector::CloningAction Action =
|
|
Director->handleInstruction(VMap, &*II, NewBB);
|
|
// If the cloning director says stop, we want to stop everything, not
|
|
// just break out of the loop (which would cause the terminator to be
|
|
// cloned). The cloning director is responsible for inserting a proper
|
|
// terminator into the new basic block in this case.
|
|
if (Action == CloningDirector::StopCloningBB)
|
|
return;
|
|
// If the cloning director says skip, continue to the next instruction.
|
|
// In this case, the cloning director is responsible for mapping the
|
|
// skipped instruction to some value that is defined in the new
|
|
// basic block.
|
|
if (Action == CloningDirector::SkipInstruction)
|
|
continue;
|
|
}
|
|
|
|
Instruction *NewInst = II->clone();
|
|
|
|
// Eagerly remap operands to the newly cloned instruction, except for PHI
|
|
// nodes for which we defer processing until we update the CFG.
|
|
if (!isa<PHINode>(NewInst)) {
|
|
RemapInstruction(NewInst, VMap,
|
|
ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
|
|
TypeMapper, Materializer);
|
|
|
|
// If we can simplify this instruction to some other value, simply add
|
|
// a mapping to that value rather than inserting a new instruction into
|
|
// the basic block.
|
|
if (Value *V =
|
|
SimplifyInstruction(NewInst, BB->getModule()->getDataLayout())) {
|
|
// On the off-chance that this simplifies to an instruction in the old
|
|
// function, map it back into the new function.
|
|
if (Value *MappedV = VMap.lookup(V))
|
|
V = MappedV;
|
|
|
|
VMap[&*II] = V;
|
|
delete NewInst;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (II->hasName())
|
|
NewInst->setName(II->getName()+NameSuffix);
|
|
VMap[&*II] = NewInst; // Add instruction map to value.
|
|
NewBB->getInstList().push_back(NewInst);
|
|
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 (Director) {
|
|
CloningDirector::CloningAction Action
|
|
= Director->handleInstruction(VMap, OldTI, NewBB);
|
|
// If the cloning director says stop, we want to stop everything, not
|
|
// just break out of the loop (which would cause the terminator to be
|
|
// cloned). The cloning director is responsible for inserting a proper
|
|
// terminator into the new basic block in this case.
|
|
if (Action == CloningDirector::StopCloningBB)
|
|
return;
|
|
if (Action == CloningDirector::CloneSuccessors) {
|
|
// If the director says to skip with a terminate instruction, we still
|
|
// need to clone this block's successors.
|
|
const TerminatorInst *TI = NewBB->getTerminator();
|
|
for (const BasicBlock *Succ : TI->successors())
|
|
ToClone.push_back(Succ);
|
|
return;
|
|
}
|
|
assert(Action != CloningDirector::SkipInstruction &&
|
|
"SkipInstruction is not valid for terminators.");
|
|
}
|
|
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) {
|
|
Value *V = VMap[BI->getCondition()];
|
|
Cond = dyn_cast_or_null<ConstantInt>(V);
|
|
}
|
|
|
|
// Constant fold to uncond branch!
|
|
if (Cond) {
|
|
BasicBlock *Dest = BI->getSuccessor(!Cond->getZExtValue());
|
|
VMap[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) { // Or known constant after constant prop in the callee...
|
|
Value *V = VMap[SI->getCondition()];
|
|
Cond = dyn_cast_or_null<ConstantInt>(V);
|
|
}
|
|
if (Cond) { // Constant fold to uncond branch!
|
|
SwitchInst::ConstCaseIt Case = SI->findCaseValue(Cond);
|
|
BasicBlock *Dest = const_cast<BasicBlock*>(Case.getCaseSuccessor());
|
|
VMap[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);
|
|
VMap[OldTI] = NewInst; // Add instruction map to value.
|
|
|
|
// Recursively clone any reachable successor blocks.
|
|
const TerminatorInst *TI = BB->getTerminator();
|
|
for (const BasicBlock *Succ : TI->successors())
|
|
ToClone.push_back(Succ);
|
|
}
|
|
|
|
if (CodeInfo) {
|
|
CodeInfo->ContainsCalls |= hasCalls;
|
|
CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
|
|
CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
|
|
BB != &BB->getParent()->front();
|
|
}
|
|
}
|
|
|
|
/// This works like CloneAndPruneFunctionInto, except that it does not clone the
|
|
/// entire function. Instead it starts at an instruction provided by the caller
|
|
/// and copies (and prunes) only the code reachable from that instruction.
|
|
void llvm::CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
|
|
const Instruction *StartingInst,
|
|
ValueToValueMapTy &VMap,
|
|
bool ModuleLevelChanges,
|
|
SmallVectorImpl<ReturnInst *> &Returns,
|
|
const char *NameSuffix,
|
|
ClonedCodeInfo *CodeInfo,
|
|
CloningDirector *Director) {
|
|
assert(NameSuffix && "NameSuffix cannot be null!");
|
|
|
|
ValueMapTypeRemapper *TypeMapper = nullptr;
|
|
ValueMaterializer *Materializer = nullptr;
|
|
|
|
if (Director) {
|
|
TypeMapper = Director->getTypeRemapper();
|
|
Materializer = Director->getValueMaterializer();
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
// If the cloning starts at the beginning of the function, verify that
|
|
// the function arguments are mapped.
|
|
if (!StartingInst)
|
|
for (const Argument &II : OldFunc->args())
|
|
assert(VMap.count(&II) && "No mapping from source argument specified!");
|
|
#endif
|
|
|
|
PruningFunctionCloner PFC(NewFunc, OldFunc, VMap, ModuleLevelChanges,
|
|
NameSuffix, CodeInfo, Director);
|
|
const BasicBlock *StartingBB;
|
|
if (StartingInst)
|
|
StartingBB = StartingInst->getParent();
|
|
else {
|
|
StartingBB = &OldFunc->getEntryBlock();
|
|
StartingInst = &StartingBB->front();
|
|
}
|
|
|
|
// Clone the entry block, and anything recursively reachable from it.
|
|
std::vector<const BasicBlock*> CloneWorklist;
|
|
PFC.CloneBlock(StartingBB, StartingInst->getIterator(), CloneWorklist);
|
|
while (!CloneWorklist.empty()) {
|
|
const BasicBlock *BB = CloneWorklist.back();
|
|
CloneWorklist.pop_back();
|
|
PFC.CloneBlock(BB, BB->begin(), 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 (const BasicBlock &BI : *OldFunc) {
|
|
Value *V = VMap[&BI];
|
|
BasicBlock *NewBB = cast_or_null<BasicBlock>(V);
|
|
if (!NewBB) continue; // Dead block.
|
|
|
|
// Add the new block to the new function.
|
|
NewFunc->getBasicBlockList().push_back(NewBB);
|
|
|
|
// Handle PHI nodes specially, as we have to remove references to dead
|
|
// blocks.
|
|
for (BasicBlock::const_iterator I = BI.begin(), E = BI.end(); I != E; ++I) {
|
|
// PHI nodes may have been remapped to non-PHI nodes by the caller or
|
|
// during the cloning process.
|
|
if (const PHINode *PN = dyn_cast<PHINode>(I)) {
|
|
if (isa<PHINode>(VMap[PN]))
|
|
PHIToResolve.push_back(PN);
|
|
else
|
|
break;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Finally, remap the terminator instructions, as those can't be remapped
|
|
// until all BBs are mapped.
|
|
RemapInstruction(NewBB->getTerminator(), VMap,
|
|
ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
|
|
TypeMapper, Materializer);
|
|
}
|
|
|
|
// 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>(VMap[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>(VMap[OPN]);
|
|
for (unsigned pred = 0, e = NumPreds; pred != e; ++pred) {
|
|
Value *V = VMap[PN->getIncomingBlock(pred)];
|
|
if (BasicBlock *MappedBlock = cast_or_null<BasicBlock>(V)) {
|
|
Value *InVal = MapValue(PN->getIncomingValue(pred),
|
|
VMap,
|
|
ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
|
|
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(VMap[&*OldI] == PN && "VMap mismatch");
|
|
VMap[&*OldI] = NV;
|
|
PN->eraseFromParent();
|
|
++OldI;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Make a second pass over the PHINodes now that all of them have been
|
|
// remapped into the new function, simplifying the PHINode and performing any
|
|
// recursive simplifications exposed. This will transparently update the
|
|
// WeakVH in the VMap. Notably, we rely on that so that if we coalesce
|
|
// two PHINodes, the iteration over the old PHIs remains valid, and the
|
|
// mapping will just map us to the new node (which may not even be a PHI
|
|
// node).
|
|
for (unsigned Idx = 0, Size = PHIToResolve.size(); Idx != Size; ++Idx)
|
|
if (PHINode *PN = dyn_cast<PHINode>(VMap[PHIToResolve[Idx]]))
|
|
recursivelySimplifyInstruction(PN);
|
|
|
|
// Now that the inlined function body has been fully constructed, go through
|
|
// and zap unconditional fall-through branches. This happens all the time when
|
|
// specializing code: code specialization turns conditional branches into
|
|
// uncond branches, and this code folds them.
|
|
Function::iterator Begin = cast<BasicBlock>(VMap[StartingBB])->getIterator();
|
|
Function::iterator I = Begin;
|
|
while (I != NewFunc->end()) {
|
|
// Check if this block has become dead during inlining or other
|
|
// simplifications. Note that the first block will appear dead, as it has
|
|
// not yet been wired up properly.
|
|
if (I != Begin && (pred_begin(&*I) == pred_end(&*I) ||
|
|
I->getSinglePredecessor() == &*I)) {
|
|
BasicBlock *DeadBB = &*I++;
|
|
DeleteDeadBlock(DeadBB);
|
|
continue;
|
|
}
|
|
|
|
// We need to simplify conditional branches and switches with a constant
|
|
// operand. We try to prune these out when cloning, but if the
|
|
// simplification required looking through PHI nodes, those are only
|
|
// available after forming the full basic block. That may leave some here,
|
|
// and we still want to prune the dead code as early as possible.
|
|
ConstantFoldTerminator(&*I);
|
|
|
|
BranchInst *BI = dyn_cast<BranchInst>(I->getTerminator());
|
|
if (!BI || BI->isConditional()) { ++I; continue; }
|
|
|
|
BasicBlock *Dest = BI->getSuccessor(0);
|
|
if (!Dest->getSinglePredecessor()) {
|
|
++I; continue;
|
|
}
|
|
|
|
// We shouldn't be able to get single-entry PHI nodes here, as instsimplify
|
|
// above should have zapped all of them..
|
|
assert(!isa<PHINode>(Dest->begin()));
|
|
|
|
// We know all single-entry PHI nodes in the inlined function have been
|
|
// removed, so we just need to splice the blocks.
|
|
BI->eraseFromParent();
|
|
|
|
// Make all PHI nodes that referred to Dest now refer to I as their source.
|
|
Dest->replaceAllUsesWith(&*I);
|
|
|
|
// Move all the instructions in the succ to the pred.
|
|
I->getInstList().splice(I->end(), Dest->getInstList());
|
|
|
|
// Remove the dest block.
|
|
Dest->eraseFromParent();
|
|
|
|
// Do not increment I, iteratively merge all things this block branches to.
|
|
}
|
|
|
|
// Make a final pass over the basic blocks from the old function to gather
|
|
// any return instructions which survived folding. We have to do this here
|
|
// because we can iteratively remove and merge returns above.
|
|
for (Function::iterator I = cast<BasicBlock>(VMap[StartingBB])->getIterator(),
|
|
E = NewFunc->end();
|
|
I != E; ++I)
|
|
if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator()))
|
|
Returns.push_back(RI);
|
|
}
|
|
|
|
|
|
/// 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,
|
|
ValueToValueMapTy &VMap,
|
|
bool ModuleLevelChanges,
|
|
SmallVectorImpl<ReturnInst*> &Returns,
|
|
const char *NameSuffix,
|
|
ClonedCodeInfo *CodeInfo,
|
|
Instruction *TheCall) {
|
|
CloneAndPruneIntoFromInst(NewFunc, OldFunc, &OldFunc->front().front(), VMap,
|
|
ModuleLevelChanges, Returns, NameSuffix, CodeInfo,
|
|
nullptr);
|
|
}
|
|
|
|
/// \brief Remaps instructions in \p Blocks using the mapping in \p VMap.
|
|
void llvm::remapInstructionsInBlocks(
|
|
const SmallVectorImpl<BasicBlock *> &Blocks, ValueToValueMapTy &VMap) {
|
|
// Rewrite the code to refer to itself.
|
|
for (auto *BB : Blocks)
|
|
for (auto &Inst : *BB)
|
|
RemapInstruction(&Inst, VMap,
|
|
RF_NoModuleLevelChanges | RF_IgnoreMissingEntries);
|
|
}
|
|
|
|
/// \brief Clones a loop \p OrigLoop. Returns the loop and the blocks in \p
|
|
/// Blocks.
|
|
///
|
|
/// Updates LoopInfo and DominatorTree assuming the loop is dominated by block
|
|
/// \p LoopDomBB. Insert the new blocks before block specified in \p Before.
|
|
Loop *llvm::cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB,
|
|
Loop *OrigLoop, ValueToValueMapTy &VMap,
|
|
const Twine &NameSuffix, LoopInfo *LI,
|
|
DominatorTree *DT,
|
|
SmallVectorImpl<BasicBlock *> &Blocks) {
|
|
Function *F = OrigLoop->getHeader()->getParent();
|
|
Loop *ParentLoop = OrigLoop->getParentLoop();
|
|
|
|
Loop *NewLoop = new Loop();
|
|
if (ParentLoop)
|
|
ParentLoop->addChildLoop(NewLoop);
|
|
else
|
|
LI->addTopLevelLoop(NewLoop);
|
|
|
|
BasicBlock *OrigPH = OrigLoop->getLoopPreheader();
|
|
assert(OrigPH && "No preheader");
|
|
BasicBlock *NewPH = CloneBasicBlock(OrigPH, VMap, NameSuffix, F);
|
|
// To rename the loop PHIs.
|
|
VMap[OrigPH] = NewPH;
|
|
Blocks.push_back(NewPH);
|
|
|
|
// Update LoopInfo.
|
|
if (ParentLoop)
|
|
ParentLoop->addBasicBlockToLoop(NewPH, *LI);
|
|
|
|
// Update DominatorTree.
|
|
DT->addNewBlock(NewPH, LoopDomBB);
|
|
|
|
for (BasicBlock *BB : OrigLoop->getBlocks()) {
|
|
BasicBlock *NewBB = CloneBasicBlock(BB, VMap, NameSuffix, F);
|
|
VMap[BB] = NewBB;
|
|
|
|
// Update LoopInfo.
|
|
NewLoop->addBasicBlockToLoop(NewBB, *LI);
|
|
|
|
// Update DominatorTree.
|
|
BasicBlock *IDomBB = DT->getNode(BB)->getIDom()->getBlock();
|
|
DT->addNewBlock(NewBB, cast<BasicBlock>(VMap[IDomBB]));
|
|
|
|
Blocks.push_back(NewBB);
|
|
}
|
|
|
|
// Move them physically from the end of the block list.
|
|
F->getBasicBlockList().splice(Before->getIterator(), F->getBasicBlockList(),
|
|
NewPH);
|
|
F->getBasicBlockList().splice(Before->getIterator(), F->getBasicBlockList(),
|
|
NewLoop->getHeader()->getIterator(), F->end());
|
|
|
|
return NewLoop;
|
|
}
|