forked from OSchip/llvm-project
820 lines
32 KiB
C++
820 lines
32 KiB
C++
//===- CloneFunction.cpp - Clone a function into another function ---------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the CloneFunctionInto interface, which is used as the
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// low-level function cloner. This is used by the CloneFunction and function
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// inliner to do the dirty work of copying the body of a function around.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/SetVector.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Analysis/ConstantFolding.h"
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#include "llvm/Analysis/InstructionSimplify.h"
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/IR/CFG.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/DebugInfo.h"
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#include "llvm/IR/DerivedTypes.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/GlobalVariable.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/Metadata.h"
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#include "llvm/IR/Module.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Transforms/Utils/Cloning.h"
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#include "llvm/Transforms/Utils/Local.h"
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#include "llvm/Transforms/Utils/ValueMapper.h"
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#include <map>
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using namespace llvm;
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/// See comments in Cloning.h.
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BasicBlock *llvm::CloneBasicBlock(const BasicBlock *BB, ValueToValueMapTy &VMap,
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const Twine &NameSuffix, Function *F,
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ClonedCodeInfo *CodeInfo,
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DebugInfoFinder *DIFinder) {
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DenseMap<const MDNode *, MDNode *> Cache;
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BasicBlock *NewBB = BasicBlock::Create(BB->getContext(), "", F);
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if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
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bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false;
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// Loop over all instructions, and copy them over.
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for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end();
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II != IE; ++II) {
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if (DIFinder && F->getParent() && II->getDebugLoc())
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DIFinder->processLocation(*F->getParent(), II->getDebugLoc().get());
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Instruction *NewInst = II->clone();
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if (II->hasName())
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NewInst->setName(II->getName()+NameSuffix);
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NewBB->getInstList().push_back(NewInst);
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VMap[&*II] = NewInst; // Add instruction map to value.
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hasCalls |= (isa<CallInst>(II) && !isa<DbgInfoIntrinsic>(II));
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if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
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if (isa<ConstantInt>(AI->getArraySize()))
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hasStaticAllocas = true;
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else
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hasDynamicAllocas = true;
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}
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}
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if (CodeInfo) {
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CodeInfo->ContainsCalls |= hasCalls;
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CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
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CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
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BB != &BB->getParent()->getEntryBlock();
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}
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return NewBB;
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}
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// Clone OldFunc into NewFunc, transforming the old arguments into references to
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// VMap values.
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//
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void llvm::CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
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ValueToValueMapTy &VMap,
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bool ModuleLevelChanges,
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SmallVectorImpl<ReturnInst*> &Returns,
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const char *NameSuffix, ClonedCodeInfo *CodeInfo,
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ValueMapTypeRemapper *TypeMapper,
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ValueMaterializer *Materializer) {
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assert(NameSuffix && "NameSuffix cannot be null!");
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#ifndef NDEBUG
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for (const Argument &I : OldFunc->args())
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assert(VMap.count(&I) && "No mapping from source argument specified!");
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#endif
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// Copy all attributes other than those stored in the AttributeList. We need
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// to remap the parameter indices of the AttributeList.
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AttributeList NewAttrs = NewFunc->getAttributes();
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NewFunc->copyAttributesFrom(OldFunc);
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NewFunc->setAttributes(NewAttrs);
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// Fix up the personality function that got copied over.
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if (OldFunc->hasPersonalityFn())
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NewFunc->setPersonalityFn(
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MapValue(OldFunc->getPersonalityFn(), VMap,
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ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
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TypeMapper, Materializer));
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SmallVector<AttributeSet, 4> NewArgAttrs(NewFunc->arg_size());
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AttributeList OldAttrs = OldFunc->getAttributes();
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// Clone any argument attributes that are present in the VMap.
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for (const Argument &OldArg : OldFunc->args()) {
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if (Argument *NewArg = dyn_cast<Argument>(VMap[&OldArg])) {
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NewArgAttrs[NewArg->getArgNo()] =
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OldAttrs.getParamAttributes(OldArg.getArgNo());
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}
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}
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NewFunc->setAttributes(
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AttributeList::get(NewFunc->getContext(), OldAttrs.getFnAttributes(),
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OldAttrs.getRetAttributes(), NewArgAttrs));
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bool MustCloneSP =
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OldFunc->getParent() && OldFunc->getParent() == NewFunc->getParent();
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DISubprogram *SP = OldFunc->getSubprogram();
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if (SP) {
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assert(!MustCloneSP || ModuleLevelChanges);
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// Add mappings for some DebugInfo nodes that we don't want duplicated
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// even if they're distinct.
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auto &MD = VMap.MD();
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MD[SP->getUnit()].reset(SP->getUnit());
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MD[SP->getType()].reset(SP->getType());
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MD[SP->getFile()].reset(SP->getFile());
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// If we're not cloning into the same module, no need to clone the
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// subprogram
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if (!MustCloneSP)
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MD[SP].reset(SP);
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}
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SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
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OldFunc->getAllMetadata(MDs);
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for (auto MD : MDs) {
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NewFunc->addMetadata(
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MD.first,
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*MapMetadata(MD.second, VMap,
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ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
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TypeMapper, Materializer));
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}
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// When we remap instructions, we want to avoid duplicating inlined
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// DISubprograms, so record all subprograms we find as we duplicate
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// instructions and then freeze them in the MD map.
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DebugInfoFinder DIFinder;
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// Loop over all of the basic blocks in the function, cloning them as
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// appropriate. Note that we save BE this way in order to handle cloning of
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// recursive functions into themselves.
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//
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for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
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BI != BE; ++BI) {
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const BasicBlock &BB = *BI;
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// Create a new basic block and copy instructions into it!
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BasicBlock *CBB = CloneBasicBlock(&BB, VMap, NameSuffix, NewFunc, CodeInfo,
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SP ? &DIFinder : nullptr);
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// Add basic block mapping.
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VMap[&BB] = CBB;
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// It is only legal to clone a function if a block address within that
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// function is never referenced outside of the function. Given that, we
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// want to map block addresses from the old function to block addresses in
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// the clone. (This is different from the generic ValueMapper
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// implementation, which generates an invalid blockaddress when
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// cloning a function.)
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if (BB.hasAddressTaken()) {
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Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
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const_cast<BasicBlock*>(&BB));
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VMap[OldBBAddr] = BlockAddress::get(NewFunc, CBB);
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}
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// Note return instructions for the caller.
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if (ReturnInst *RI = dyn_cast<ReturnInst>(CBB->getTerminator()))
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Returns.push_back(RI);
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}
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for (DISubprogram *ISP : DIFinder.subprograms()) {
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if (ISP != SP) {
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VMap.MD()[ISP].reset(ISP);
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}
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}
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// Loop over all of the instructions in the function, fixing up operand
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// references as we go. This uses VMap to do all the hard work.
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for (Function::iterator BB =
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cast<BasicBlock>(VMap[&OldFunc->front()])->getIterator(),
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BE = NewFunc->end();
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BB != BE; ++BB)
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// Loop over all instructions, fixing each one as we find it...
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for (Instruction &II : *BB)
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RemapInstruction(&II, VMap,
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ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges,
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TypeMapper, Materializer);
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}
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/// Return a copy of the specified function and add it to that function's
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/// module. Also, any references specified in the VMap are changed to refer to
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/// their mapped value instead of the original one. If any of the arguments to
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/// the function are in the VMap, the arguments are deleted from the resultant
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/// function. The VMap is updated to include mappings from all of the
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/// instructions and basicblocks in the function from their old to new values.
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///
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Function *llvm::CloneFunction(Function *F, ValueToValueMapTy &VMap,
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ClonedCodeInfo *CodeInfo) {
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std::vector<Type*> ArgTypes;
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// The user might be deleting arguments to the function by specifying them in
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// the VMap. If so, we need to not add the arguments to the arg ty vector
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//
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for (const Argument &I : F->args())
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if (VMap.count(&I) == 0) // Haven't mapped the argument to anything yet?
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ArgTypes.push_back(I.getType());
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// Create a new function type...
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FunctionType *FTy = FunctionType::get(F->getFunctionType()->getReturnType(),
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ArgTypes, F->getFunctionType()->isVarArg());
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// Create the new function...
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Function *NewF =
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Function::Create(FTy, F->getLinkage(), F->getName(), F->getParent());
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// Loop over the arguments, copying the names of the mapped arguments over...
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Function::arg_iterator DestI = NewF->arg_begin();
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for (const Argument & I : F->args())
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if (VMap.count(&I) == 0) { // Is this argument preserved?
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DestI->setName(I.getName()); // Copy the name over...
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VMap[&I] = &*DestI++; // Add mapping to VMap
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}
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SmallVector<ReturnInst*, 8> Returns; // Ignore returns cloned.
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CloneFunctionInto(NewF, F, VMap, F->getSubprogram() != nullptr, Returns, "",
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CodeInfo);
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return NewF;
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}
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namespace {
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/// This is a private class used to implement CloneAndPruneFunctionInto.
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struct PruningFunctionCloner {
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Function *NewFunc;
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const Function *OldFunc;
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ValueToValueMapTy &VMap;
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bool ModuleLevelChanges;
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const char *NameSuffix;
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ClonedCodeInfo *CodeInfo;
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public:
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PruningFunctionCloner(Function *newFunc, const Function *oldFunc,
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ValueToValueMapTy &valueMap, bool moduleLevelChanges,
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const char *nameSuffix, ClonedCodeInfo *codeInfo)
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: NewFunc(newFunc), OldFunc(oldFunc), VMap(valueMap),
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ModuleLevelChanges(moduleLevelChanges), NameSuffix(nameSuffix),
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CodeInfo(codeInfo) {}
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/// The specified block is found to be reachable, clone it and
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/// anything that it can reach.
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void CloneBlock(const BasicBlock *BB,
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BasicBlock::const_iterator StartingInst,
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std::vector<const BasicBlock*> &ToClone);
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};
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}
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/// The specified block is found to be reachable, clone it and
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/// anything that it can reach.
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void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
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BasicBlock::const_iterator StartingInst,
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std::vector<const BasicBlock*> &ToClone){
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WeakTrackingVH &BBEntry = VMap[BB];
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// Have we already cloned this block?
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if (BBEntry) return;
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// Nope, clone it now.
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BasicBlock *NewBB;
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BBEntry = NewBB = BasicBlock::Create(BB->getContext());
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if (BB->hasName()) NewBB->setName(BB->getName()+NameSuffix);
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// It is only legal to clone a function if a block address within that
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// function is never referenced outside of the function. Given that, we
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// want to map block addresses from the old function to block addresses in
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// the clone. (This is different from the generic ValueMapper
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// implementation, which generates an invalid blockaddress when
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// cloning a function.)
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//
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// Note that we don't need to fix the mapping for unreachable blocks;
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// the default mapping there is safe.
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if (BB->hasAddressTaken()) {
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Constant *OldBBAddr = BlockAddress::get(const_cast<Function*>(OldFunc),
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const_cast<BasicBlock*>(BB));
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VMap[OldBBAddr] = BlockAddress::get(NewFunc, NewBB);
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}
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bool hasCalls = false, hasDynamicAllocas = false, hasStaticAllocas = false;
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// Loop over all instructions, and copy them over, DCE'ing as we go. This
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// loop doesn't include the terminator.
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for (BasicBlock::const_iterator II = StartingInst, IE = --BB->end();
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II != IE; ++II) {
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Instruction *NewInst = II->clone();
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// Eagerly remap operands to the newly cloned instruction, except for PHI
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// nodes for which we defer processing until we update the CFG.
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if (!isa<PHINode>(NewInst)) {
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RemapInstruction(NewInst, VMap,
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ModuleLevelChanges ? RF_None : RF_NoModuleLevelChanges);
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// If we can simplify this instruction to some other value, simply add
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// a mapping to that value rather than inserting a new instruction into
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// the basic block.
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if (Value *V =
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SimplifyInstruction(NewInst, BB->getModule()->getDataLayout())) {
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// On the off-chance that this simplifies to an instruction in the old
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// function, map it back into the new function.
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if (Value *MappedV = VMap.lookup(V))
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V = MappedV;
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if (!NewInst->mayHaveSideEffects()) {
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VMap[&*II] = V;
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NewInst->deleteValue();
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continue;
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}
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}
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}
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if (II->hasName())
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NewInst->setName(II->getName()+NameSuffix);
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VMap[&*II] = NewInst; // Add instruction map to value.
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NewBB->getInstList().push_back(NewInst);
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hasCalls |= (isa<CallInst>(II) && !isa<DbgInfoIntrinsic>(II));
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if (CodeInfo)
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if (auto CS = ImmutableCallSite(&*II))
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if (CS.hasOperandBundles())
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CodeInfo->OperandBundleCallSites.push_back(NewInst);
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if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
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if (isa<ConstantInt>(AI->getArraySize()))
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hasStaticAllocas = true;
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else
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hasDynamicAllocas = true;
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}
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}
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// Finally, clone over the terminator.
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const TerminatorInst *OldTI = BB->getTerminator();
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bool TerminatorDone = false;
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if (const BranchInst *BI = dyn_cast<BranchInst>(OldTI)) {
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if (BI->isConditional()) {
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// If the condition was a known constant in the callee...
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ConstantInt *Cond = dyn_cast<ConstantInt>(BI->getCondition());
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// Or is a known constant in the caller...
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if (!Cond) {
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Value *V = VMap.lookup(BI->getCondition());
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Cond = dyn_cast_or_null<ConstantInt>(V);
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}
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// Constant fold to uncond branch!
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if (Cond) {
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BasicBlock *Dest = BI->getSuccessor(!Cond->getZExtValue());
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VMap[OldTI] = BranchInst::Create(Dest, NewBB);
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ToClone.push_back(Dest);
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TerminatorDone = true;
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}
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}
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} else if (const SwitchInst *SI = dyn_cast<SwitchInst>(OldTI)) {
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// If switching on a value known constant in the caller.
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ConstantInt *Cond = dyn_cast<ConstantInt>(SI->getCondition());
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if (!Cond) { // Or known constant after constant prop in the callee...
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Value *V = VMap.lookup(SI->getCondition());
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Cond = dyn_cast_or_null<ConstantInt>(V);
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}
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if (Cond) { // Constant fold to uncond branch!
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SwitchInst::ConstCaseHandle Case = *SI->findCaseValue(Cond);
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BasicBlock *Dest = const_cast<BasicBlock*>(Case.getCaseSuccessor());
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VMap[OldTI] = BranchInst::Create(Dest, NewBB);
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ToClone.push_back(Dest);
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TerminatorDone = true;
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}
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}
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if (!TerminatorDone) {
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Instruction *NewInst = OldTI->clone();
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if (OldTI->hasName())
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NewInst->setName(OldTI->getName()+NameSuffix);
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NewBB->getInstList().push_back(NewInst);
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VMap[OldTI] = NewInst; // Add instruction map to value.
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if (CodeInfo)
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if (auto CS = ImmutableCallSite(OldTI))
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if (CS.hasOperandBundles())
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CodeInfo->OperandBundleCallSites.push_back(NewInst);
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// Recursively clone any reachable successor blocks.
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const TerminatorInst *TI = BB->getTerminator();
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for (const BasicBlock *Succ : TI->successors())
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ToClone.push_back(Succ);
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}
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if (CodeInfo) {
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CodeInfo->ContainsCalls |= hasCalls;
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CodeInfo->ContainsDynamicAllocas |= hasDynamicAllocas;
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CodeInfo->ContainsDynamicAllocas |= hasStaticAllocas &&
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BB != &BB->getParent()->front();
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}
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}
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/// This works like CloneAndPruneFunctionInto, except that it does not clone the
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/// entire function. Instead it starts at an instruction provided by the caller
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/// and copies (and prunes) only the code reachable from that instruction.
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void llvm::CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
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const Instruction *StartingInst,
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ValueToValueMapTy &VMap,
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bool ModuleLevelChanges,
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SmallVectorImpl<ReturnInst *> &Returns,
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const char *NameSuffix,
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ClonedCodeInfo *CodeInfo) {
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assert(NameSuffix && "NameSuffix cannot be null!");
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ValueMapTypeRemapper *TypeMapper = nullptr;
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ValueMaterializer *Materializer = nullptr;
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#ifndef NDEBUG
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// If the cloning starts at the beginning of the function, verify that
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// the function arguments are mapped.
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if (!StartingInst)
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for (const Argument &II : OldFunc->args())
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assert(VMap.count(&II) && "No mapping from source argument specified!");
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#endif
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PruningFunctionCloner PFC(NewFunc, OldFunc, VMap, ModuleLevelChanges,
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NameSuffix, CodeInfo);
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const BasicBlock *StartingBB;
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if (StartingInst)
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StartingBB = StartingInst->getParent();
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else {
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StartingBB = &OldFunc->getEntryBlock();
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StartingInst = &StartingBB->front();
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}
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// Clone the entry block, and anything recursively reachable from it.
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std::vector<const BasicBlock*> CloneWorklist;
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PFC.CloneBlock(StartingBB, StartingInst->getIterator(), CloneWorklist);
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while (!CloneWorklist.empty()) {
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const BasicBlock *BB = CloneWorklist.back();
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CloneWorklist.pop_back();
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PFC.CloneBlock(BB, BB->begin(), CloneWorklist);
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}
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// Loop over all of the basic blocks in the old function. If the block was
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// reachable, we have cloned it and the old block is now in the value map:
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// insert it into the new function in the right order. If not, ignore it.
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//
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// Defer PHI resolution until rest of function is resolved.
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SmallVector<const PHINode*, 16> PHIToResolve;
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for (const BasicBlock &BI : *OldFunc) {
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Value *V = VMap.lookup(&BI);
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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.lookup(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; // Revisit the next entry.
|
|
--e;
|
|
}
|
|
}
|
|
}
|
|
|
|
// 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 (const auto &PCI : PredCount) {
|
|
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
|
|
// WeakTrackingVH 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).
|
|
const DataLayout &DL = NewFunc->getParent()->getDataLayout();
|
|
SmallSetVector<const Value *, 8> Worklist;
|
|
for (unsigned Idx = 0, Size = PHIToResolve.size(); Idx != Size; ++Idx)
|
|
if (isa<PHINode>(VMap[PHIToResolve[Idx]]))
|
|
Worklist.insert(PHIToResolve[Idx]);
|
|
|
|
// Note that we must test the size on each iteration, the worklist can grow.
|
|
for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
|
|
const Value *OrigV = Worklist[Idx];
|
|
auto *I = dyn_cast_or_null<Instruction>(VMap.lookup(OrigV));
|
|
if (!I)
|
|
continue;
|
|
|
|
// Skip over non-intrinsic callsites, we don't want to remove any nodes from
|
|
// the CGSCC.
|
|
CallSite CS = CallSite(I);
|
|
if (CS && CS.getCalledFunction() && !CS.getCalledFunction()->isIntrinsic())
|
|
continue;
|
|
|
|
// See if this instruction simplifies.
|
|
Value *SimpleV = SimplifyInstruction(I, DL);
|
|
if (!SimpleV)
|
|
continue;
|
|
|
|
// Stash away all the uses of the old instruction so we can check them for
|
|
// recursive simplifications after a RAUW. This is cheaper than checking all
|
|
// uses of To on the recursive step in most cases.
|
|
for (const User *U : OrigV->users())
|
|
Worklist.insert(cast<Instruction>(U));
|
|
|
|
// Replace the instruction with its simplified value.
|
|
I->replaceAllUsesWith(SimpleV);
|
|
|
|
// If the original instruction had no side effects, remove it.
|
|
if (isInstructionTriviallyDead(I))
|
|
I->eraseFromParent();
|
|
else
|
|
VMap[OrigV] = I;
|
|
}
|
|
|
|
// 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);
|
|
}
|
|
|
|
/// \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_IgnoreMissingLocals);
|
|
}
|
|
|
|
/// \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) {
|
|
assert(OrigLoop->getSubLoops().empty() &&
|
|
"Loop to be cloned cannot have inner loop");
|
|
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);
|
|
|
|
// Add DominatorTree node. After seeing all blocks, update to correct IDom.
|
|
DT->addNewBlock(NewBB, NewPH);
|
|
|
|
Blocks.push_back(NewBB);
|
|
}
|
|
|
|
for (BasicBlock *BB : OrigLoop->getBlocks()) {
|
|
// Update DominatorTree.
|
|
BasicBlock *IDomBB = DT->getNode(BB)->getIDom()->getBlock();
|
|
DT->changeImmediateDominator(cast<BasicBlock>(VMap[BB]),
|
|
cast<BasicBlock>(VMap[IDomBB]));
|
|
}
|
|
|
|
// 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;
|
|
}
|
|
|
|
/// \brief Duplicate non-Phi instructions from the beginning of block up to
|
|
/// StopAt instruction into a split block between BB and its predecessor.
|
|
BasicBlock *
|
|
llvm::DuplicateInstructionsInSplitBetween(BasicBlock *BB, BasicBlock *PredBB,
|
|
Instruction *StopAt,
|
|
ValueToValueMapTy &ValueMapping) {
|
|
// We are going to have to map operands from the original BB block to the new
|
|
// copy of the block 'NewBB'. If there are PHI nodes in BB, evaluate them to
|
|
// account for entry from PredBB.
|
|
BasicBlock::iterator BI = BB->begin();
|
|
for (; PHINode *PN = dyn_cast<PHINode>(BI); ++BI)
|
|
ValueMapping[PN] = PN->getIncomingValueForBlock(PredBB);
|
|
|
|
BasicBlock *NewBB = SplitEdge(PredBB, BB);
|
|
NewBB->setName(PredBB->getName() + ".split");
|
|
Instruction *NewTerm = NewBB->getTerminator();
|
|
|
|
// Clone the non-phi instructions of BB into NewBB, keeping track of the
|
|
// mapping and using it to remap operands in the cloned instructions.
|
|
for (; StopAt != &*BI; ++BI) {
|
|
Instruction *New = BI->clone();
|
|
New->setName(BI->getName());
|
|
New->insertBefore(NewTerm);
|
|
ValueMapping[&*BI] = New;
|
|
|
|
// Remap operands to patch up intra-block references.
|
|
for (unsigned i = 0, e = New->getNumOperands(); i != e; ++i)
|
|
if (Instruction *Inst = dyn_cast<Instruction>(New->getOperand(i))) {
|
|
auto I = ValueMapping.find(Inst);
|
|
if (I != ValueMapping.end())
|
|
New->setOperand(i, I->second);
|
|
}
|
|
}
|
|
|
|
return NewBB;
|
|
}
|