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//===- CodeExtractor.cpp - Pull code region into a new function -----------===//
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// The LLVM Compiler Infrastructure
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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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// This file implements the interface to tear out a code region, such as an
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// individual loop or a parallel section, into a new function, replacing it with
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// a call to the new function.
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Utils/FunctionUtils.h"
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Instructions.h"
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#include "llvm/Intrinsics.h"
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#include "llvm/LLVMContext.h"
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#include "llvm/Module.h"
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#include "llvm/Pass.h"
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/Analysis/Verifier.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/ADT/StringExtras.h"
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// Provide a command-line option to aggregate function arguments into a struct
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// for functions produced by the code extractor. This is useful when converting
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// extracted functions to pthread-based code, as only one argument (void*) can
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// be passed in to pthread_create().
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AggregateArgsOpt("aggregate-extracted-args", cl::Hidden,
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cl::desc("Aggregate arguments to code-extracted functions"));
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typedef SetVector<Value*> Values;
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SetVector<BasicBlock*> BlocksToExtract;
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unsigned NumExitBlocks;
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CodeExtractor(DominatorTree* dt = 0, bool AggArgs = false)
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: DT(dt), AggregateArgs(AggArgs||AggregateArgsOpt), NumExitBlocks(~0U) {}
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Function *ExtractCodeRegion(const std::vector<BasicBlock*> &code);
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bool isEligible(const std::vector<BasicBlock*> &code);
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/// definedInRegion - Return true if the specified value is defined in the
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bool definedInRegion(Value *V) const {
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if (Instruction *I = dyn_cast<Instruction>(V))
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if (BlocksToExtract.count(I->getParent()))
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/// definedInCaller - Return true if the specified value is defined in the
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/// function being code extracted, but not in the region being extracted.
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/// These values must be passed in as live-ins to the function.
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bool definedInCaller(Value *V) const {
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if (isa<Argument>(V)) return true;
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if (Instruction *I = dyn_cast<Instruction>(V))
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if (!BlocksToExtract.count(I->getParent()))
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void severSplitPHINodes(BasicBlock *&Header);
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void splitReturnBlocks();
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void findInputsOutputs(Values &inputs, Values &outputs);
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Function *constructFunction(const Values &inputs,
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const Values &outputs,
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BasicBlock *newRootNode, BasicBlock *newHeader,
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Function *oldFunction, Module *M);
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void moveCodeToFunction(Function *newFunction);
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void emitCallAndSwitchStatement(Function *newFunction,
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BasicBlock *newHeader,
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/// severSplitPHINodes - If a PHI node has multiple inputs from outside of the
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/// region, we need to split the entry block of the region so that the PHI node
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/// is easier to deal with.
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void CodeExtractor::severSplitPHINodes(BasicBlock *&Header) {
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bool HasPredsFromRegion = false;
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unsigned NumPredsOutsideRegion = 0;
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if (Header != &Header->getParent()->getEntryBlock()) {
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PHINode *PN = dyn_cast<PHINode>(Header->begin());
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if (!PN) return; // No PHI nodes.
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// If the header node contains any PHI nodes, check to see if there is more
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// than one entry from outside the region. If so, we need to sever the
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// header block into two.
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for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
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if (BlocksToExtract.count(PN->getIncomingBlock(i)))
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HasPredsFromRegion = true;
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++NumPredsOutsideRegion;
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// If there is one (or fewer) predecessor from outside the region, we don't
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// need to do anything special.
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if (NumPredsOutsideRegion <= 1) return;
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// Otherwise, we need to split the header block into two pieces: one
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// containing PHI nodes merging values from outside of the region, and a
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// second that contains all of the code for the block and merges back any
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// incoming values from inside of the region.
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BasicBlock::iterator AfterPHIs = Header->getFirstNonPHI();
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BasicBlock *NewBB = Header->splitBasicBlock(AfterPHIs,
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Header->getName()+".ce");
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// We only want to code extract the second block now, and it becomes the new
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// header of the region.
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BasicBlock *OldPred = Header;
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BlocksToExtract.remove(OldPred);
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BlocksToExtract.insert(NewBB);
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// Okay, update dominator sets. The blocks that dominate the new one are the
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// blocks that dominate TIBB plus the new block itself.
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DT->splitBlock(NewBB);
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// Okay, now we need to adjust the PHI nodes and any branches from within the
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// region to go to the new header block instead of the old header block.
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if (HasPredsFromRegion) {
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PHINode *PN = cast<PHINode>(OldPred->begin());
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// Loop over all of the predecessors of OldPred that are in the region,
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// changing them to branch to NewBB instead.
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for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
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if (BlocksToExtract.count(PN->getIncomingBlock(i))) {
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TerminatorInst *TI = PN->getIncomingBlock(i)->getTerminator();
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TI->replaceUsesOfWith(OldPred, NewBB);
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// Okay, everthing within the region is now branching to the right block, we
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// just have to update the PHI nodes now, inserting PHI nodes into NewBB.
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for (AfterPHIs = OldPred->begin(); isa<PHINode>(AfterPHIs); ++AfterPHIs) {
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PHINode *PN = cast<PHINode>(AfterPHIs);
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// Create a new PHI node in the new region, which has an incoming value
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// from OldPred of PN.
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PHINode *NewPN = PHINode::Create(PN->getType(), PN->getName()+".ce",
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NewPN->addIncoming(PN, OldPred);
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// Loop over all of the incoming value in PN, moving them to NewPN if they
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// are from the extracted region.
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for (unsigned i = 0; i != PN->getNumIncomingValues(); ++i) {
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if (BlocksToExtract.count(PN->getIncomingBlock(i))) {
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NewPN->addIncoming(PN->getIncomingValue(i), PN->getIncomingBlock(i));
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PN->removeIncomingValue(i);
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void CodeExtractor::splitReturnBlocks() {
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for (SetVector<BasicBlock*>::iterator I = BlocksToExtract.begin(),
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E = BlocksToExtract.end(); I != E; ++I)
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if (ReturnInst *RI = dyn_cast<ReturnInst>((*I)->getTerminator())) {
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BasicBlock *New = (*I)->splitBasicBlock(RI, (*I)->getName()+".ret");
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// Old dominates New. New node domiantes all other nodes dominated
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DomTreeNode *OldNode = DT->getNode(*I);
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SmallVector<DomTreeNode*, 8> Children;
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for (DomTreeNode::iterator DI = OldNode->begin(), DE = OldNode->end();
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Children.push_back(*DI);
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DomTreeNode *NewNode = DT->addNewBlock(New, *I);
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for (SmallVector<DomTreeNode*, 8>::iterator I = Children.begin(),
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E = Children.end(); I != E; ++I)
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DT->changeImmediateDominator(*I, NewNode);
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// findInputsOutputs - Find inputs to, outputs from the code region.
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void CodeExtractor::findInputsOutputs(Values &inputs, Values &outputs) {
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std::set<BasicBlock*> ExitBlocks;
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for (SetVector<BasicBlock*>::const_iterator ci = BlocksToExtract.begin(),
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ce = BlocksToExtract.end(); ci != ce; ++ci) {
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BasicBlock *BB = *ci;
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for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
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// If a used value is defined outside the region, it's an input. If an
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// instruction is used outside the region, it's an output.
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for (User::op_iterator O = I->op_begin(), E = I->op_end(); O != E; ++O)
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if (definedInCaller(*O))
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// Consider uses of this instruction (outputs).
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for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
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if (!definedInRegion(*UI)) {
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// Keep track of the exit blocks from the region.
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TerminatorInst *TI = BB->getTerminator();
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for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
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if (!BlocksToExtract.count(TI->getSuccessor(i)))
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ExitBlocks.insert(TI->getSuccessor(i));
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} // for: basic blocks
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NumExitBlocks = ExitBlocks.size();
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/// constructFunction - make a function based on inputs and outputs, as follows:
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/// f(in0, ..., inN, out0, ..., outN)
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Function *CodeExtractor::constructFunction(const Values &inputs,
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const Values &outputs,
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BasicBlock *newRootNode,
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BasicBlock *newHeader,
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Function *oldFunction,
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DEBUG(dbgs() << "inputs: " << inputs.size() << "\n");
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DEBUG(dbgs() << "outputs: " << outputs.size() << "\n");
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// This function returns unsigned, outputs will go back by reference.
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switch (NumExitBlocks) {
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case 1: RetTy = Type::getVoidTy(header->getContext()); break;
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case 2: RetTy = Type::getInt1Ty(header->getContext()); break;
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default: RetTy = Type::getInt16Ty(header->getContext()); break;
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std::vector<const Type*> paramTy;
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// Add the types of the input values to the function's argument list
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for (Values::const_iterator i = inputs.begin(),
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e = inputs.end(); i != e; ++i) {
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const Value *value = *i;
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DEBUG(dbgs() << "value used in func: " << *value << "\n");
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paramTy.push_back(value->getType());
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// Add the types of the output values to the function's argument list.
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for (Values::const_iterator I = outputs.begin(), E = outputs.end();
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DEBUG(dbgs() << "instr used in func: " << **I << "\n");
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paramTy.push_back((*I)->getType());
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paramTy.push_back(PointerType::getUnqual((*I)->getType()));
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DEBUG(dbgs() << "Function type: " << *RetTy << " f(");
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for (std::vector<const Type*>::iterator i = paramTy.begin(),
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e = paramTy.end(); i != e; ++i)
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DEBUG(dbgs() << **i << ", ");
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DEBUG(dbgs() << ")\n");
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if (AggregateArgs && (inputs.size() + outputs.size() > 0)) {
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PointerType *StructPtr =
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PointerType::getUnqual(StructType::get(M->getContext(), paramTy));
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paramTy.push_back(StructPtr);
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const FunctionType *funcType =
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FunctionType::get(RetTy, paramTy, false);
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// Create the new function
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Function *newFunction = Function::Create(funcType,
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GlobalValue::InternalLinkage,
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oldFunction->getName() + "_" +
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header->getName(), M);
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// If the old function is no-throw, so is the new one.
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if (oldFunction->doesNotThrow())
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newFunction->setDoesNotThrow(true);
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newFunction->getBasicBlockList().push_back(newRootNode);
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// Create an iterator to name all of the arguments we inserted.
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Function::arg_iterator AI = newFunction->arg_begin();
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// Rewrite all users of the inputs in the extracted region to use the
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// arguments (or appropriate addressing into struct) instead.
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for (unsigned i = 0, e = inputs.size(); i != e; ++i) {
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Idx[0] = Constant::getNullValue(Type::getInt32Ty(header->getContext()));
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Idx[1] = ConstantInt::get(Type::getInt32Ty(header->getContext()), i);
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TerminatorInst *TI = newFunction->begin()->getTerminator();
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GetElementPtrInst *GEP =
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GetElementPtrInst::Create(AI, Idx, Idx+2,
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"gep_" + inputs[i]->getName(), TI);
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RewriteVal = new LoadInst(GEP, "loadgep_" + inputs[i]->getName(), TI);
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std::vector<User*> Users(inputs[i]->use_begin(), inputs[i]->use_end());
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for (std::vector<User*>::iterator use = Users.begin(), useE = Users.end();
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if (Instruction* inst = dyn_cast<Instruction>(*use))
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if (BlocksToExtract.count(inst->getParent()))
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inst->replaceUsesOfWith(inputs[i], RewriteVal);
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// Set names for input and output arguments.
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if (!AggregateArgs) {
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AI = newFunction->arg_begin();
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for (unsigned i = 0, e = inputs.size(); i != e; ++i, ++AI)
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AI->setName(inputs[i]->getName());
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for (unsigned i = 0, e = outputs.size(); i != e; ++i, ++AI)
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AI->setName(outputs[i]->getName()+".out");
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// Rewrite branches to basic blocks outside of the loop to new dummy blocks
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// within the new function. This must be done before we lose track of which
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// blocks were originally in the code region.
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std::vector<User*> Users(header->use_begin(), header->use_end());
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for (unsigned i = 0, e = Users.size(); i != e; ++i)
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// The BasicBlock which contains the branch is not in the region
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// modify the branch target to a new block
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if (TerminatorInst *TI = dyn_cast<TerminatorInst>(Users[i]))
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if (!BlocksToExtract.count(TI->getParent()) &&
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TI->getParent()->getParent() == oldFunction)
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TI->replaceUsesOfWith(header, newHeader);
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/// FindPhiPredForUseInBlock - Given a value and a basic block, find a PHI
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/// that uses the value within the basic block, and return the predecessor
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/// block associated with that use, or return 0 if none is found.
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static BasicBlock* FindPhiPredForUseInBlock(Value* Used, BasicBlock* BB) {
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for (Value::use_iterator UI = Used->use_begin(),
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UE = Used->use_end(); UI != UE; ++UI) {
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PHINode *P = dyn_cast<PHINode>(*UI);
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if (P && P->getParent() == BB)
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return P->getIncomingBlock(UI);
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/// emitCallAndSwitchStatement - This method sets up the caller side by adding
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/// the call instruction, splitting any PHI nodes in the header block as
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emitCallAndSwitchStatement(Function *newFunction, BasicBlock *codeReplacer,
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Values &inputs, Values &outputs) {
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// Emit a call to the new function, passing in: *pointer to struct (if
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// aggregating parameters), or plan inputs and allocated memory for outputs
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std::vector<Value*> params, StructValues, ReloadOutputs, Reloads;
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LLVMContext &Context = newFunction->getContext();
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// Add inputs as params, or to be filled into the struct
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for (Values::iterator i = inputs.begin(), e = inputs.end(); i != e; ++i)
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StructValues.push_back(*i);
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params.push_back(*i);
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// Create allocas for the outputs
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for (Values::iterator i = outputs.begin(), e = outputs.end(); i != e; ++i) {
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StructValues.push_back(*i);
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new AllocaInst((*i)->getType(), 0, (*i)->getName()+".loc",
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codeReplacer->getParent()->begin()->begin());
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ReloadOutputs.push_back(alloca);
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params.push_back(alloca);
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AllocaInst *Struct = 0;
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if (AggregateArgs && (inputs.size() + outputs.size() > 0)) {
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std::vector<const Type*> ArgTypes;
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for (Values::iterator v = StructValues.begin(),
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ve = StructValues.end(); v != ve; ++v)
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ArgTypes.push_back((*v)->getType());
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// Allocate a struct at the beginning of this function
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Type *StructArgTy = StructType::get(newFunction->getContext(), ArgTypes);
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new AllocaInst(StructArgTy, 0, "structArg",
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codeReplacer->getParent()->begin()->begin());
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params.push_back(Struct);
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for (unsigned i = 0, e = inputs.size(); i != e; ++i) {
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Idx[0] = Constant::getNullValue(Type::getInt32Ty(Context));
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Idx[1] = ConstantInt::get(Type::getInt32Ty(Context), i);
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GetElementPtrInst *GEP =
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GetElementPtrInst::Create(Struct, Idx, Idx + 2,
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"gep_" + StructValues[i]->getName());
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codeReplacer->getInstList().push_back(GEP);
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StoreInst *SI = new StoreInst(StructValues[i], GEP);
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codeReplacer->getInstList().push_back(SI);
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// Emit the call to the function
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CallInst *call = CallInst::Create(newFunction, params.begin(), params.end(),
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NumExitBlocks > 1 ? "targetBlock" : "");
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codeReplacer->getInstList().push_back(call);
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Function::arg_iterator OutputArgBegin = newFunction->arg_begin();
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unsigned FirstOut = inputs.size();
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std::advance(OutputArgBegin, inputs.size());
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// Reload the outputs passed in by reference
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for (unsigned i = 0, e = outputs.size(); i != e; ++i) {
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Idx[0] = Constant::getNullValue(Type::getInt32Ty(Context));
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Idx[1] = ConstantInt::get(Type::getInt32Ty(Context), FirstOut + i);
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GetElementPtrInst *GEP
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= GetElementPtrInst::Create(Struct, Idx, Idx + 2,
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"gep_reload_" + outputs[i]->getName());
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codeReplacer->getInstList().push_back(GEP);
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Output = ReloadOutputs[i];
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LoadInst *load = new LoadInst(Output, outputs[i]->getName()+".reload");
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Reloads.push_back(load);
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codeReplacer->getInstList().push_back(load);
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std::vector<User*> Users(outputs[i]->use_begin(), outputs[i]->use_end());
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for (unsigned u = 0, e = Users.size(); u != e; ++u) {
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Instruction *inst = cast<Instruction>(Users[u]);
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if (!BlocksToExtract.count(inst->getParent()))
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inst->replaceUsesOfWith(outputs[i], load);
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// Now we can emit a switch statement using the call as a value.
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SwitchInst *TheSwitch =
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SwitchInst::Create(Constant::getNullValue(Type::getInt16Ty(Context)),
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codeReplacer, 0, codeReplacer);
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// Since there may be multiple exits from the original region, make the new
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// function return an unsigned, switch on that number. This loop iterates
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// over all of the blocks in the extracted region, updating any terminator
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// instructions in the to-be-extracted region that branch to blocks that are
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// not in the region to be extracted.
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std::map<BasicBlock*, BasicBlock*> ExitBlockMap;
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unsigned switchVal = 0;
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for (SetVector<BasicBlock*>::const_iterator i = BlocksToExtract.begin(),
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e = BlocksToExtract.end(); i != e; ++i) {
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TerminatorInst *TI = (*i)->getTerminator();
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for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
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if (!BlocksToExtract.count(TI->getSuccessor(i))) {
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BasicBlock *OldTarget = TI->getSuccessor(i);
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// add a new basic block which returns the appropriate value
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BasicBlock *&NewTarget = ExitBlockMap[OldTarget];
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// If we don't already have an exit stub for this non-extracted
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// destination, create one now!
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NewTarget = BasicBlock::Create(Context,
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OldTarget->getName() + ".exitStub",
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unsigned SuccNum = switchVal++;
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switch (NumExitBlocks) {
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case 1: break; // No value needed.
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case 2: // Conditional branch, return a bool
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brVal = ConstantInt::get(Type::getInt1Ty(Context), !SuccNum);
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brVal = ConstantInt::get(Type::getInt16Ty(Context), SuccNum);
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ReturnInst *NTRet = ReturnInst::Create(Context, brVal, NewTarget);
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// Update the switch instruction.
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TheSwitch->addCase(ConstantInt::get(Type::getInt16Ty(Context),
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// Restore values just before we exit
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Function::arg_iterator OAI = OutputArgBegin;
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for (unsigned out = 0, e = outputs.size(); out != e; ++out) {
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// For an invoke, the normal destination is the only one that is
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// dominated by the result of the invocation
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BasicBlock *DefBlock = cast<Instruction>(outputs[out])->getParent();
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bool DominatesDef = true;
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if (InvokeInst *Invoke = dyn_cast<InvokeInst>(outputs[out])) {
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DefBlock = Invoke->getNormalDest();
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// Make sure we are looking at the original successor block, not
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// at a newly inserted exit block, which won't be in the dominator
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for (std::map<BasicBlock*, BasicBlock*>::iterator I =
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ExitBlockMap.begin(), E = ExitBlockMap.end(); I != E; ++I)
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if (DefBlock == I->second) {
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// In the extract block case, if the block we are extracting ends
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// with an invoke instruction, make sure that we don't emit a
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// store of the invoke value for the unwind block.
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if (!DT && DefBlock != OldTarget)
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DominatesDef = false;
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DominatesDef = DT->dominates(DefBlock, OldTarget);
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// If the output value is used by a phi in the target block,
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// then we need to test for dominance of the phi's predecessor
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// instead. Unfortunately, this a little complicated since we
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// have already rewritten uses of the value to uses of the reload.
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BasicBlock* pred = FindPhiPredForUseInBlock(Reloads[out],
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if (pred && DT && DT->dominates(DefBlock, pred))
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Idx[0] = Constant::getNullValue(Type::getInt32Ty(Context));
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Idx[1] = ConstantInt::get(Type::getInt32Ty(Context),
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GetElementPtrInst *GEP =
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GetElementPtrInst::Create(OAI, Idx, Idx + 2,
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"gep_" + outputs[out]->getName(),
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new StoreInst(outputs[out], GEP, NTRet);
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new StoreInst(outputs[out], OAI, NTRet);
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// Advance output iterator even if we don't emit a store
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if (!AggregateArgs) ++OAI;
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// rewrite the original branch instruction with this new target
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TI->setSuccessor(i, NewTarget);
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// Now that we've done the deed, simplify the switch instruction.
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const Type *OldFnRetTy = TheSwitch->getParent()->getParent()->getReturnType();
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switch (NumExitBlocks) {
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// There are no successors (the block containing the switch itself), which
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// means that previously this was the last part of the function, and hence
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// this should be rewritten as a `ret'
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// Check if the function should return a value
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if (OldFnRetTy->isVoidTy()) {
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ReturnInst::Create(Context, 0, TheSwitch); // Return void
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} else if (OldFnRetTy == TheSwitch->getCondition()->getType()) {
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// return what we have
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ReturnInst::Create(Context, TheSwitch->getCondition(), TheSwitch);
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// Otherwise we must have code extracted an unwind or something, just
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// return whatever we want.
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ReturnInst::Create(Context,
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Constant::getNullValue(OldFnRetTy), TheSwitch);
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TheSwitch->eraseFromParent();
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// Only a single destination, change the switch into an unconditional
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BranchInst::Create(TheSwitch->getSuccessor(1), TheSwitch);
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TheSwitch->eraseFromParent();
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BranchInst::Create(TheSwitch->getSuccessor(1), TheSwitch->getSuccessor(2),
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TheSwitch->eraseFromParent();
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// Otherwise, make the default destination of the switch instruction be one
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// of the other successors.
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TheSwitch->setOperand(0, call);
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TheSwitch->setSuccessor(0, TheSwitch->getSuccessor(NumExitBlocks));
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TheSwitch->removeCase(NumExitBlocks); // Remove redundant case
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void CodeExtractor::moveCodeToFunction(Function *newFunction) {
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Function *oldFunc = (*BlocksToExtract.begin())->getParent();
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Function::BasicBlockListType &oldBlocks = oldFunc->getBasicBlockList();
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Function::BasicBlockListType &newBlocks = newFunction->getBasicBlockList();
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for (SetVector<BasicBlock*>::const_iterator i = BlocksToExtract.begin(),
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e = BlocksToExtract.end(); i != e; ++i) {
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// Delete the basic block from the old function, and the list of blocks
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oldBlocks.remove(*i);
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// Insert this basic block into the new function
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newBlocks.push_back(*i);
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/// ExtractRegion - Removes a loop from a function, replaces it with a call to
642
/// new function. Returns pointer to the new function.
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/// find inputs and outputs for the region
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/// for inputs: add to function as args, map input instr* to arg#
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/// for outputs: add allocas for scalars,
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/// add to func as args, map output instr* to arg#
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/// rewrite func to use argument #s instead of instr*
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/// for each scalar output in the function: at every exit, store intermediate
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/// computed result back into memory.
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Function *CodeExtractor::
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ExtractCodeRegion(const std::vector<BasicBlock*> &code) {
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if (!isEligible(code))
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// 1) Find inputs, outputs
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// 2) Construct new function
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// * Add allocas for defs, pass as args by reference
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// * Pass in uses as args
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// 3) Move code region, add call instr to func
668
BlocksToExtract.insert(code.begin(), code.end());
670
Values inputs, outputs;
672
// Assumption: this is a single-entry code region, and the header is the first
673
// block in the region.
674
BasicBlock *header = code[0];
676
for (unsigned i = 1, e = code.size(); i != e; ++i)
677
for (pred_iterator PI = pred_begin(code[i]), E = pred_end(code[i]);
679
assert(BlocksToExtract.count(*PI) &&
680
"No blocks in this region may have entries from outside the region"
681
" except for the first block!");
683
// If we have to split PHI nodes or the entry block, do so now.
684
severSplitPHINodes(header);
686
// If we have any return instructions in the region, split those blocks so
687
// that the return is not in the region.
690
Function *oldFunction = header->getParent();
692
// This takes place of the original loop
693
BasicBlock *codeReplacer = BasicBlock::Create(header->getContext(),
694
"codeRepl", oldFunction,
697
// The new function needs a root node because other nodes can branch to the
698
// head of the region, but the entry node of a function cannot have preds.
699
BasicBlock *newFuncRoot = BasicBlock::Create(header->getContext(),
701
newFuncRoot->getInstList().push_back(BranchInst::Create(header));
703
// Find inputs to, outputs from the code region.
704
findInputsOutputs(inputs, outputs);
706
// Construct new function based on inputs/outputs & add allocas for all defs.
707
Function *newFunction = constructFunction(inputs, outputs, header,
709
codeReplacer, oldFunction,
710
oldFunction->getParent());
712
emitCallAndSwitchStatement(newFunction, codeReplacer, inputs, outputs);
714
moveCodeToFunction(newFunction);
716
// Loop over all of the PHI nodes in the header block, and change any
717
// references to the old incoming edge to be the new incoming edge.
718
for (BasicBlock::iterator I = header->begin(); isa<PHINode>(I); ++I) {
719
PHINode *PN = cast<PHINode>(I);
720
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
721
if (!BlocksToExtract.count(PN->getIncomingBlock(i)))
722
PN->setIncomingBlock(i, newFuncRoot);
725
// Look at all successors of the codeReplacer block. If any of these blocks
726
// had PHI nodes in them, we need to update the "from" block to be the code
727
// replacer, not the original block in the extracted region.
728
std::vector<BasicBlock*> Succs(succ_begin(codeReplacer),
729
succ_end(codeReplacer));
730
for (unsigned i = 0, e = Succs.size(); i != e; ++i)
731
for (BasicBlock::iterator I = Succs[i]->begin(); isa<PHINode>(I); ++I) {
732
PHINode *PN = cast<PHINode>(I);
733
std::set<BasicBlock*> ProcessedPreds;
734
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
735
if (BlocksToExtract.count(PN->getIncomingBlock(i))) {
736
if (ProcessedPreds.insert(PN->getIncomingBlock(i)).second)
737
PN->setIncomingBlock(i, codeReplacer);
739
// There were multiple entries in the PHI for this block, now there
740
// is only one, so remove the duplicated entries.
741
PN->removeIncomingValue(i, false);
747
//cerr << "NEW FUNCTION: " << *newFunction;
748
// verifyFunction(*newFunction);
750
// cerr << "OLD FUNCTION: " << *oldFunction;
751
// verifyFunction(*oldFunction);
753
DEBUG(if (verifyFunction(*newFunction))
754
llvm_report_error("verifyFunction failed!"));
758
bool CodeExtractor::isEligible(const std::vector<BasicBlock*> &code) {
759
// Deny code region if it contains allocas or vastarts.
760
for (std::vector<BasicBlock*>::const_iterator BB = code.begin(), e=code.end();
762
for (BasicBlock::const_iterator I = (*BB)->begin(), Ie = (*BB)->end();
764
if (isa<AllocaInst>(*I))
766
else if (const CallInst *CI = dyn_cast<CallInst>(I))
767
if (const Function *F = CI->getCalledFunction())
768
if (F->getIntrinsicID() == Intrinsic::vastart)
774
/// ExtractCodeRegion - slurp a sequence of basic blocks into a brand new
777
Function* llvm::ExtractCodeRegion(DominatorTree &DT,
778
const std::vector<BasicBlock*> &code,
779
bool AggregateArgs) {
780
return CodeExtractor(&DT, AggregateArgs).ExtractCodeRegion(code);
783
/// ExtractBasicBlock - slurp a natural loop into a brand new function
785
Function* llvm::ExtractLoop(DominatorTree &DT, Loop *L, bool AggregateArgs) {
786
return CodeExtractor(&DT, AggregateArgs).ExtractCodeRegion(L->getBlocks());
789
/// ExtractBasicBlock - slurp a basic block into a brand new function
791
Function* llvm::ExtractBasicBlock(BasicBlock *BB, bool AggregateArgs) {
792
std::vector<BasicBlock*> Blocks;
793
Blocks.push_back(BB);
794
return CodeExtractor(0, AggregateArgs).ExtractCodeRegion(Blocks);
added
removed
libclamav/c++/llvm/lib/Transforms/Utils/CodeExtractor.cpp
