From 69fdd9f14af75b7ce3f4348545dd914331e2f595 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Thu, 18 Mar 2004 05:28:49 +0000 Subject: [PATCH] Seriously simplify and correct the PHI node handling code. llvm-svn: 12487 --- lib/Transforms/Utils/CodeExtractor.cpp | 190 ++++--------------------- 1 file changed, 28 insertions(+), 162 deletions(-) diff --git a/lib/Transforms/Utils/CodeExtractor.cpp b/lib/Transforms/Utils/CodeExtractor.cpp index 694f06bdc6f..4e131b4a11a 100644 --- a/lib/Transforms/Utils/CodeExtractor.cpp +++ b/lib/Transforms/Utils/CodeExtractor.cpp @@ -30,20 +30,8 @@ using namespace llvm; namespace { - - /// getFunctionArg - Return a pointer to F's ARGNOth argument. - /// - Argument *getFunctionArg(Function *F, unsigned argno) { - Function::aiterator I = F->abegin(); - std::advance(I, argno); - return I; - } - class CodeExtractor { typedef std::vector Values; - typedef std::vector > PhiValChangesTy; - typedef std::map PhiVal2ArgTy; - PhiVal2ArgTy PhiVal2Arg; std::set BlocksToExtract; DominatorSet *DS; public: @@ -56,15 +44,9 @@ namespace { BasicBlock *newHeader, BasicBlock *newRootNode); - void processPhiNodeInputs(PHINode *Phi, - Values &inputs, - BasicBlock *newHeader, - BasicBlock *newRootNode); - - void rewritePhiNodes(Function *F, BasicBlock *newFuncRoot); - Function *constructFunction(const Values &inputs, const Values &outputs, + BasicBlock *header, BasicBlock *newRootNode, BasicBlock *newHeader, Function *oldFunction, Module *M); @@ -78,95 +60,6 @@ namespace { }; } -void CodeExtractor::processPhiNodeInputs(PHINode *Phi, - Values &inputs, - BasicBlock *codeReplacer, - BasicBlock *newFuncRoot) { - // Separate incoming values and BasicBlocks as internal/external. We ignore - // the case where both the value and BasicBlock are internal, because we don't - // need to do a thing. - std::vector EValEBB; - std::vector EValIBB; - std::vector IValEBB; - - for (unsigned i = 0, e = Phi->getNumIncomingValues(); i != e; ++i) { - Value *phiVal = Phi->getIncomingValue(i); - if (Instruction *Inst = dyn_cast(phiVal)) { - if (BlocksToExtract.count(Inst->getParent())) { - if (!BlocksToExtract.count(Phi->getIncomingBlock(i))) - IValEBB.push_back(i); - } else { - if (BlocksToExtract.count(Phi->getIncomingBlock(i))) - EValIBB.push_back(i); - else - EValEBB.push_back(i); - } - } else if (Argument *Arg = dyn_cast(phiVal)) { - // arguments are external - if (BlocksToExtract.count(Phi->getIncomingBlock(i))) - EValIBB.push_back(i); - else - EValEBB.push_back(i); - } else { - // Globals/Constants are internal, but considered `external' if they are - // coming from an external block. - if (!BlocksToExtract.count(Phi->getIncomingBlock(i))) - EValEBB.push_back(i); - } - } - - // Both value and block are external. Need to group all of these, have an - // external phi, pass the result as an argument, and have THIS phi use that - // result. - if (EValEBB.size() > 0) { - if (EValEBB.size() == 1) { - // Now if it's coming from the newFuncRoot, it's that funky input - unsigned phiIdx = EValEBB[0]; - if (!isa(Phi->getIncomingValue(phiIdx))) { - PhiVal2Arg[Phi].push_back(std::make_pair(phiIdx, inputs.size())); - // We can just pass this value in as argument - inputs.push_back(Phi->getIncomingValue(phiIdx)); - } - Phi->setIncomingBlock(phiIdx, newFuncRoot); - } else { - PHINode *externalPhi = new PHINode(Phi->getType(), "extPhi"); - codeReplacer->getInstList().insert(codeReplacer->begin(), externalPhi); - for (std::vector::iterator i = EValEBB.begin(), - e = EValEBB.end(); i != e; ++i) { - externalPhi->addIncoming(Phi->getIncomingValue(*i), - Phi->getIncomingBlock(*i)); - - // We make these values invalid instead of deleting them because that - // would shift the indices of other values... The fixPhiNodes should - // clean these phi nodes up later. - Phi->setIncomingValue(*i, 0); - Phi->setIncomingBlock(*i, 0); - } - PhiVal2Arg[Phi].push_back(std::make_pair(Phi->getNumIncomingValues(), - inputs.size())); - // We can just pass this value in as argument - inputs.push_back(externalPhi); - } - } - - // When the value is external, but block internal... just pass it in as - // argument, no change to phi node - for (std::vector::iterator i = EValIBB.begin(), - e = EValIBB.end(); i != e; ++i) { - // rewrite the phi input node to be an argument - PhiVal2Arg[Phi].push_back(std::make_pair(*i, inputs.size())); - inputs.push_back(Phi->getIncomingValue(*i)); - } - - // Value internal, block external this can happen if we are extracting a part - // of a loop. - for (std::vector::iterator i = IValEBB.begin(), - e = IValEBB.end(); i != e; ++i) { - assert(0 && "Cannot (YET) handle internal values via external blocks"); - } -} - - void CodeExtractor::findInputsOutputs(Values &inputs, Values &outputs, BasicBlock *newHeader, BasicBlock *newRootNode) { @@ -176,8 +69,13 @@ void CodeExtractor::findInputsOutputs(Values &inputs, Values &outputs, for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { // If a used value is defined outside the region, it's an input. If an // instruction is used outside the region, it's an output. - if (PHINode *Phi = dyn_cast(I)) { - processPhiNodeInputs(Phi, inputs, newHeader, newRootNode); + if (PHINode *PN = dyn_cast(I)) { + for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { + Value *V = PN->getIncomingValue(i); + if (!BlocksToExtract.count(PN->getIncomingBlock(i)) && + (isa(V) || isa(V))) + inputs.push_back(V); + } } else { // All other instructions go through the generic input finder // Loop over the operands of each instruction (inputs) @@ -203,53 +101,18 @@ void CodeExtractor::findInputsOutputs(Values &inputs, Values &outputs, } // for: basic blocks } -void CodeExtractor::rewritePhiNodes(Function *F, - BasicBlock *newFuncRoot) { - // Write any changes that were saved before: use function arguments as inputs - for (PhiVal2ArgTy::iterator i = PhiVal2Arg.begin(), e = PhiVal2Arg.end(); - i != e; ++i) { - PHINode *phi = i->first; - PhiValChangesTy &values = i->second; - for (unsigned cIdx = 0, ce = values.size(); cIdx != ce; ++cIdx) - { - unsigned phiValueIdx = values[cIdx].first, argNum = values[cIdx].second; - if (phiValueIdx < phi->getNumIncomingValues()) - phi->setIncomingValue(phiValueIdx, getFunctionArg(F, argNum)); - else - phi->addIncoming(getFunctionArg(F, argNum), newFuncRoot); - } - } - - // Delete any invalid Phi node inputs that were marked as NULL previously - for (PhiVal2ArgTy::iterator i = PhiVal2Arg.begin(), e = PhiVal2Arg.end(); - i != e; ++i) { - PHINode *phi = i->first; - for (unsigned idx = 0, end = phi->getNumIncomingValues(); idx != end; ++idx) - { - if (phi->getIncomingValue(idx) == 0 && phi->getIncomingBlock(idx) == 0) { - phi->removeIncomingValue(idx); - --idx; - --end; - } - } - } - - // We are done with the saved values - PhiVal2Arg.clear(); -} - - /// constructFunction - make a function based on inputs and outputs, as follows: /// f(in0, ..., inN, out0, ..., outN) /// Function *CodeExtractor::constructFunction(const Values &inputs, const Values &outputs, + BasicBlock *header, BasicBlock *newRootNode, BasicBlock *newHeader, - Function *oldFunction, Module *M) { + Function *oldFunction, + Module *M) { DEBUG(std::cerr << "inputs: " << inputs.size() << "\n"); DEBUG(std::cerr << "outputs: " << outputs.size() << "\n"); - BasicBlock *header = *BlocksToExtract.begin(); // This function returns unsigned, outputs will go back by reference. Type *retTy = Type::UShortTy; @@ -308,17 +171,13 @@ Function *CodeExtractor::constructFunction(const Values &inputs, // within the new function. This must be done before we lose track of which // blocks were originally in the code region. std::vector Users(header->use_begin(), header->use_end()); - for (std::vector::iterator i = Users.begin(), e = Users.end(); - i != e; ++i) { - if (BranchInst *inst = dyn_cast(*i)) { - BasicBlock *BB = inst->getParent(); - if (!BlocksToExtract.count(BB) && BB->getParent() == oldFunction) { - // The BasicBlock which contains the branch is not in the region - // modify the branch target to a new block - inst->replaceUsesOfWith(header, newHeader); - } - } - } + for (unsigned i = 0, e = Users.size(); i != e; ++i) + // The BasicBlock which contains the branch is not in the region + // modify the branch target to a new block + if (TerminatorInst *TI = dyn_cast(Users[i])) + if (!BlocksToExtract.count(TI->getParent()) && + TI->getParent()->getParent() == oldFunction) + TI->replaceUsesOfWith(header, newHeader); return newFunction; } @@ -495,16 +354,23 @@ Function *CodeExtractor::ExtractCodeRegion(const std::vector &code) // Step 2: Construct new function based on inputs/outputs, // Add allocas for all defs - Function *newFunction = constructFunction(inputs, outputs, newFuncRoot, + Function *newFunction = constructFunction(inputs, outputs, code[0], + newFuncRoot, codeReplacer, oldFunction, oldFunction->getParent()); - rewritePhiNodes(newFunction, newFuncRoot); - emitCallAndSwitchStatement(newFunction, codeReplacer, inputs, outputs); moveCodeToFunction(newFunction); + // Loop over all of the PHI nodes in the entry block (code[0]), and change any + // references to the old incoming edge to be the new incoming edge. + for (BasicBlock::iterator I = code[0]->begin(); + PHINode *PN = dyn_cast(I); ++I) + for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) + if (!BlocksToExtract.count(PN->getIncomingBlock(i))) + PN->setIncomingBlock(i, newFuncRoot); + DEBUG(if (verifyFunction(*newFunction)) abort()); return newFunction; }