1 //===- CodeExtractor.cpp - Pull code region into a new function -----------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the interface to tear out a code region, such as an
11 // individual loop or a parallel section, into a new function, replacing it with
12 // a call to the new function.
14 //===----------------------------------------------------------------------===//
16 #include "llvm/Transforms/Utils/FunctionUtils.h"
17 #include "llvm/Constants.h"
18 #include "llvm/DerivedTypes.h"
19 #include "llvm/Instructions.h"
20 #include "llvm/Intrinsics.h"
21 #include "llvm/Module.h"
22 #include "llvm/Pass.h"
23 #include "llvm/Analysis/Dominators.h"
24 #include "llvm/Analysis/DominatorInternals.h"
25 #include "llvm/Analysis/LoopInfo.h"
26 #include "llvm/Analysis/Verifier.h"
27 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
28 #include "llvm/Support/CommandLine.h"
29 #include "llvm/Support/Compiler.h"
30 #include "llvm/Support/Debug.h"
31 #include "llvm/ADT/StringExtras.h"
36 // Provide a command-line option to aggregate function arguments into a struct
37 // for functions produced by the code extrator. This is useful when converting
38 // extracted functions to pthread-based code, as only one argument (void*) can
39 // be passed in to pthread_create().
41 AggregateArgsOpt("aggregate-extracted-args", cl::Hidden,
42 cl::desc("Aggregate arguments to code-extracted functions"));
45 class VISIBILITY_HIDDEN CodeExtractor {
46 typedef std::vector<Value*> Values;
47 std::set<BasicBlock*> BlocksToExtract;
50 unsigned NumExitBlocks;
53 CodeExtractor(DominatorTree* dt = 0, bool AggArgs = false)
54 : DT(dt), AggregateArgs(AggArgs||AggregateArgsOpt), NumExitBlocks(~0U) {}
56 Function *ExtractCodeRegion(const std::vector<BasicBlock*> &code);
58 bool isEligible(const std::vector<BasicBlock*> &code);
61 /// definedInRegion - Return true if the specified value is defined in the
63 bool definedInRegion(Value *V) const {
64 if (Instruction *I = dyn_cast<Instruction>(V))
65 if (BlocksToExtract.count(I->getParent()))
70 /// definedInCaller - Return true if the specified value is defined in the
71 /// function being code extracted, but not in the region being extracted.
72 /// These values must be passed in as live-ins to the function.
73 bool definedInCaller(Value *V) const {
74 if (isa<Argument>(V)) return true;
75 if (Instruction *I = dyn_cast<Instruction>(V))
76 if (!BlocksToExtract.count(I->getParent()))
81 void severSplitPHINodes(BasicBlock *&Header);
82 void splitReturnBlocks();
83 void findInputsOutputs(Values &inputs, Values &outputs);
85 Function *constructFunction(const Values &inputs,
86 const Values &outputs,
88 BasicBlock *newRootNode, BasicBlock *newHeader,
89 Function *oldFunction, Module *M);
91 void moveCodeToFunction(Function *newFunction);
93 void emitCallAndSwitchStatement(Function *newFunction,
94 BasicBlock *newHeader,
101 /// severSplitPHINodes - If a PHI node has multiple inputs from outside of the
102 /// region, we need to split the entry block of the region so that the PHI node
103 /// is easier to deal with.
104 void CodeExtractor::severSplitPHINodes(BasicBlock *&Header) {
105 bool HasPredsFromRegion = false;
106 unsigned NumPredsOutsideRegion = 0;
108 if (Header != &Header->getParent()->getEntryBlock()) {
109 PHINode *PN = dyn_cast<PHINode>(Header->begin());
110 if (!PN) return; // No PHI nodes.
112 // If the header node contains any PHI nodes, check to see if there is more
113 // than one entry from outside the region. If so, we need to sever the
114 // header block into two.
115 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
116 if (BlocksToExtract.count(PN->getIncomingBlock(i)))
117 HasPredsFromRegion = true;
119 ++NumPredsOutsideRegion;
121 // If there is one (or fewer) predecessor from outside the region, we don't
122 // need to do anything special.
123 if (NumPredsOutsideRegion <= 1) return;
126 // Otherwise, we need to split the header block into two pieces: one
127 // containing PHI nodes merging values from outside of the region, and a
128 // second that contains all of the code for the block and merges back any
129 // incoming values from inside of the region.
130 BasicBlock::iterator AfterPHIs = Header->begin();
131 while (isa<PHINode>(AfterPHIs)) ++AfterPHIs;
132 BasicBlock *NewBB = Header->splitBasicBlock(AfterPHIs,
133 Header->getName()+".ce");
135 // We only want to code extract the second block now, and it becomes the new
136 // header of the region.
137 BasicBlock *OldPred = Header;
138 BlocksToExtract.erase(OldPred);
139 BlocksToExtract.insert(NewBB);
142 // Okay, update dominator sets. The blocks that dominate the new one are the
143 // blocks that dominate TIBB plus the new block itself.
145 DT->splitBlock(NewBB);
147 // Okay, now we need to adjust the PHI nodes and any branches from within the
148 // region to go to the new header block instead of the old header block.
149 if (HasPredsFromRegion) {
150 PHINode *PN = cast<PHINode>(OldPred->begin());
151 // Loop over all of the predecessors of OldPred that are in the region,
152 // changing them to branch to NewBB instead.
153 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
154 if (BlocksToExtract.count(PN->getIncomingBlock(i))) {
155 TerminatorInst *TI = PN->getIncomingBlock(i)->getTerminator();
156 TI->replaceUsesOfWith(OldPred, NewBB);
159 // Okay, everthing within the region is now branching to the right block, we
160 // just have to update the PHI nodes now, inserting PHI nodes into NewBB.
161 for (AfterPHIs = OldPred->begin(); isa<PHINode>(AfterPHIs); ++AfterPHIs) {
162 PHINode *PN = cast<PHINode>(AfterPHIs);
163 // Create a new PHI node in the new region, which has an incoming value
164 // from OldPred of PN.
165 PHINode *NewPN = new PHINode(PN->getType(), PN->getName()+".ce",
167 NewPN->addIncoming(PN, OldPred);
169 // Loop over all of the incoming value in PN, moving them to NewPN if they
170 // are from the extracted region.
171 for (unsigned i = 0; i != PN->getNumIncomingValues(); ++i) {
172 if (BlocksToExtract.count(PN->getIncomingBlock(i))) {
173 NewPN->addIncoming(PN->getIncomingValue(i), PN->getIncomingBlock(i));
174 PN->removeIncomingValue(i);
182 void CodeExtractor::splitReturnBlocks() {
183 for (std::set<BasicBlock*>::iterator I = BlocksToExtract.begin(),
184 E = BlocksToExtract.end(); I != E; ++I)
185 if (ReturnInst *RI = dyn_cast<ReturnInst>((*I)->getTerminator()))
186 (*I)->splitBasicBlock(RI, (*I)->getName()+".ret");
189 // findInputsOutputs - Find inputs to, outputs from the code region.
191 void CodeExtractor::findInputsOutputs(Values &inputs, Values &outputs) {
192 std::set<BasicBlock*> ExitBlocks;
193 for (std::set<BasicBlock*>::const_iterator ci = BlocksToExtract.begin(),
194 ce = BlocksToExtract.end(); ci != ce; ++ci) {
195 BasicBlock *BB = *ci;
197 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
198 // If a used value is defined outside the region, it's an input. If an
199 // instruction is used outside the region, it's an output.
200 for (User::op_iterator O = I->op_begin(), E = I->op_end(); O != E; ++O)
201 if (definedInCaller(*O))
202 inputs.push_back(*O);
204 // Consider uses of this instruction (outputs).
205 for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
207 if (!definedInRegion(*UI)) {
208 outputs.push_back(I);
213 // Keep track of the exit blocks from the region.
214 TerminatorInst *TI = BB->getTerminator();
215 for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
216 if (!BlocksToExtract.count(TI->getSuccessor(i)))
217 ExitBlocks.insert(TI->getSuccessor(i));
218 } // for: basic blocks
220 NumExitBlocks = ExitBlocks.size();
222 // Eliminate duplicates.
223 std::sort(inputs.begin(), inputs.end());
224 inputs.erase(std::unique(inputs.begin(), inputs.end()), inputs.end());
225 std::sort(outputs.begin(), outputs.end());
226 outputs.erase(std::unique(outputs.begin(), outputs.end()), outputs.end());
229 /// constructFunction - make a function based on inputs and outputs, as follows:
230 /// f(in0, ..., inN, out0, ..., outN)
232 Function *CodeExtractor::constructFunction(const Values &inputs,
233 const Values &outputs,
235 BasicBlock *newRootNode,
236 BasicBlock *newHeader,
237 Function *oldFunction,
239 DOUT << "inputs: " << inputs.size() << "\n";
240 DOUT << "outputs: " << outputs.size() << "\n";
242 // This function returns unsigned, outputs will go back by reference.
243 switch (NumExitBlocks) {
245 case 1: RetTy = Type::VoidTy; break;
246 case 2: RetTy = Type::Int1Ty; break;
247 default: RetTy = Type::Int16Ty; break;
250 std::vector<const Type*> paramTy;
252 // Add the types of the input values to the function's argument list
253 for (Values::const_iterator i = inputs.begin(),
254 e = inputs.end(); i != e; ++i) {
255 const Value *value = *i;
256 DOUT << "value used in func: " << *value << "\n";
257 paramTy.push_back(value->getType());
260 // Add the types of the output values to the function's argument list.
261 for (Values::const_iterator I = outputs.begin(), E = outputs.end();
263 DOUT << "instr used in func: " << **I << "\n";
265 paramTy.push_back((*I)->getType());
267 paramTy.push_back(PointerType::get((*I)->getType()));
270 DOUT << "Function type: " << *RetTy << " f(";
271 for (std::vector<const Type*>::iterator i = paramTy.begin(),
272 e = paramTy.end(); i != e; ++i)
276 if (AggregateArgs && (inputs.size() + outputs.size() > 0)) {
277 PointerType *StructPtr = PointerType::get(StructType::get(paramTy));
279 paramTy.push_back(StructPtr);
281 const FunctionType *funcType = FunctionType::get(RetTy, paramTy, false);
283 // Create the new function
284 Function *newFunction = new Function(funcType,
285 GlobalValue::InternalLinkage,
286 oldFunction->getName() + "_" +
287 header->getName(), M);
288 newFunction->getBasicBlockList().push_back(newRootNode);
290 // Create an iterator to name all of the arguments we inserted.
291 Function::arg_iterator AI = newFunction->arg_begin();
293 // Rewrite all users of the inputs in the extracted region to use the
294 // arguments (or appropriate addressing into struct) instead.
295 for (unsigned i = 0, e = inputs.size(); i != e; ++i) {
299 Idx[0] = Constant::getNullValue(Type::Int32Ty);
300 Idx[1] = ConstantInt::get(Type::Int32Ty, i);
301 std::string GEPname = "gep_" + inputs[i]->getName();
302 TerminatorInst *TI = newFunction->begin()->getTerminator();
303 GetElementPtrInst *GEP = new GetElementPtrInst(AI, Idx, Idx+2,
305 RewriteVal = new LoadInst(GEP, "load" + GEPname, TI);
309 std::vector<User*> Users(inputs[i]->use_begin(), inputs[i]->use_end());
310 for (std::vector<User*>::iterator use = Users.begin(), useE = Users.end();
312 if (Instruction* inst = dyn_cast<Instruction>(*use))
313 if (BlocksToExtract.count(inst->getParent()))
314 inst->replaceUsesOfWith(inputs[i], RewriteVal);
317 // Set names for input and output arguments.
318 if (!AggregateArgs) {
319 AI = newFunction->arg_begin();
320 for (unsigned i = 0, e = inputs.size(); i != e; ++i, ++AI)
321 AI->setName(inputs[i]->getName());
322 for (unsigned i = 0, e = outputs.size(); i != e; ++i, ++AI)
323 AI->setName(outputs[i]->getName()+".out");
326 // Rewrite branches to basic blocks outside of the loop to new dummy blocks
327 // within the new function. This must be done before we lose track of which
328 // blocks were originally in the code region.
329 std::vector<User*> Users(header->use_begin(), header->use_end());
330 for (unsigned i = 0, e = Users.size(); i != e; ++i)
331 // The BasicBlock which contains the branch is not in the region
332 // modify the branch target to a new block
333 if (TerminatorInst *TI = dyn_cast<TerminatorInst>(Users[i]))
334 if (!BlocksToExtract.count(TI->getParent()) &&
335 TI->getParent()->getParent() == oldFunction)
336 TI->replaceUsesOfWith(header, newHeader);
341 /// emitCallAndSwitchStatement - This method sets up the caller side by adding
342 /// the call instruction, splitting any PHI nodes in the header block as
345 emitCallAndSwitchStatement(Function *newFunction, BasicBlock *codeReplacer,
346 Values &inputs, Values &outputs) {
347 // Emit a call to the new function, passing in: *pointer to struct (if
348 // aggregating parameters), or plan inputs and allocated memory for outputs
349 std::vector<Value*> params, StructValues, ReloadOutputs;
351 // Add inputs as params, or to be filled into the struct
352 for (Values::iterator i = inputs.begin(), e = inputs.end(); i != e; ++i)
354 StructValues.push_back(*i);
356 params.push_back(*i);
358 // Create allocas for the outputs
359 for (Values::iterator i = outputs.begin(), e = outputs.end(); i != e; ++i) {
361 StructValues.push_back(*i);
364 new AllocaInst((*i)->getType(), 0, (*i)->getName()+".loc",
365 codeReplacer->getParent()->begin()->begin());
366 ReloadOutputs.push_back(alloca);
367 params.push_back(alloca);
371 AllocaInst *Struct = 0;
372 if (AggregateArgs && (inputs.size() + outputs.size() > 0)) {
373 std::vector<const Type*> ArgTypes;
374 for (Values::iterator v = StructValues.begin(),
375 ve = StructValues.end(); v != ve; ++v)
376 ArgTypes.push_back((*v)->getType());
378 // Allocate a struct at the beginning of this function
379 Type *StructArgTy = StructType::get(ArgTypes);
381 new AllocaInst(StructArgTy, 0, "structArg",
382 codeReplacer->getParent()->begin()->begin());
383 params.push_back(Struct);
385 for (unsigned i = 0, e = inputs.size(); i != e; ++i) {
387 Idx[0] = Constant::getNullValue(Type::Int32Ty);
388 Idx[1] = ConstantInt::get(Type::Int32Ty, i);
389 GetElementPtrInst *GEP =
390 new GetElementPtrInst(Struct, Idx, Idx + 2,
391 "gep_" + StructValues[i]->getName());
392 codeReplacer->getInstList().push_back(GEP);
393 StoreInst *SI = new StoreInst(StructValues[i], GEP);
394 codeReplacer->getInstList().push_back(SI);
398 // Emit the call to the function
399 CallInst *call = new CallInst(newFunction, params.begin(), params.end(),
400 NumExitBlocks > 1 ? "targetBlock" : "");
401 codeReplacer->getInstList().push_back(call);
403 Function::arg_iterator OutputArgBegin = newFunction->arg_begin();
404 unsigned FirstOut = inputs.size();
406 std::advance(OutputArgBegin, inputs.size());
408 // Reload the outputs passed in by reference
409 for (unsigned i = 0, e = outputs.size(); i != e; ++i) {
413 Idx[0] = Constant::getNullValue(Type::Int32Ty);
414 Idx[1] = ConstantInt::get(Type::Int32Ty, FirstOut + i);
415 GetElementPtrInst *GEP
416 = new GetElementPtrInst(Struct, Idx, Idx + 2,
417 "gep_reload_" + outputs[i]->getName());
418 codeReplacer->getInstList().push_back(GEP);
421 Output = ReloadOutputs[i];
423 LoadInst *load = new LoadInst(Output, outputs[i]->getName()+".reload");
424 codeReplacer->getInstList().push_back(load);
425 std::vector<User*> Users(outputs[i]->use_begin(), outputs[i]->use_end());
426 for (unsigned u = 0, e = Users.size(); u != e; ++u) {
427 Instruction *inst = cast<Instruction>(Users[u]);
428 if (!BlocksToExtract.count(inst->getParent()))
429 inst->replaceUsesOfWith(outputs[i], load);
433 // Now we can emit a switch statement using the call as a value.
434 SwitchInst *TheSwitch =
435 new SwitchInst(ConstantInt::getNullValue(Type::Int16Ty),
436 codeReplacer, 0, codeReplacer);
438 // Since there may be multiple exits from the original region, make the new
439 // function return an unsigned, switch on that number. This loop iterates
440 // over all of the blocks in the extracted region, updating any terminator
441 // instructions in the to-be-extracted region that branch to blocks that are
442 // not in the region to be extracted.
443 std::map<BasicBlock*, BasicBlock*> ExitBlockMap;
445 unsigned switchVal = 0;
446 for (std::set<BasicBlock*>::const_iterator i = BlocksToExtract.begin(),
447 e = BlocksToExtract.end(); i != e; ++i) {
448 TerminatorInst *TI = (*i)->getTerminator();
449 for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
450 if (!BlocksToExtract.count(TI->getSuccessor(i))) {
451 BasicBlock *OldTarget = TI->getSuccessor(i);
452 // add a new basic block which returns the appropriate value
453 BasicBlock *&NewTarget = ExitBlockMap[OldTarget];
455 // If we don't already have an exit stub for this non-extracted
456 // destination, create one now!
457 NewTarget = new BasicBlock(OldTarget->getName() + ".exitStub",
459 unsigned SuccNum = switchVal++;
462 switch (NumExitBlocks) {
464 case 1: break; // No value needed.
465 case 2: // Conditional branch, return a bool
466 brVal = ConstantInt::get(Type::Int1Ty, !SuccNum);
469 brVal = ConstantInt::get(Type::Int16Ty, SuccNum);
473 ReturnInst *NTRet = new ReturnInst(brVal, NewTarget);
475 // Update the switch instruction.
476 TheSwitch->addCase(ConstantInt::get(Type::Int16Ty, SuccNum),
479 // Restore values just before we exit
480 Function::arg_iterator OAI = OutputArgBegin;
481 for (unsigned out = 0, e = outputs.size(); out != e; ++out) {
482 // For an invoke, the normal destination is the only one that is
483 // dominated by the result of the invocation
484 BasicBlock *DefBlock = cast<Instruction>(outputs[out])->getParent();
486 bool DominatesDef = true;
488 if (InvokeInst *Invoke = dyn_cast<InvokeInst>(outputs[out])) {
489 DefBlock = Invoke->getNormalDest();
491 // Make sure we are looking at the original successor block, not
492 // at a newly inserted exit block, which won't be in the dominator
494 for (std::map<BasicBlock*, BasicBlock*>::iterator I =
495 ExitBlockMap.begin(), E = ExitBlockMap.end(); I != E; ++I)
496 if (DefBlock == I->second) {
501 // In the extract block case, if the block we are extracting ends
502 // with an invoke instruction, make sure that we don't emit a
503 // store of the invoke value for the unwind block.
504 if (!DT && DefBlock != OldTarget)
505 DominatesDef = false;
509 DominatesDef = DT->dominates(DefBlock, OldTarget);
514 Idx[0] = Constant::getNullValue(Type::Int32Ty);
515 Idx[1] = ConstantInt::get(Type::Int32Ty,FirstOut+out);
516 GetElementPtrInst *GEP =
517 new GetElementPtrInst(OAI, Idx, Idx + 2,
518 "gep_" + outputs[out]->getName(),
520 new StoreInst(outputs[out], GEP, NTRet);
522 new StoreInst(outputs[out], OAI, NTRet);
525 // Advance output iterator even if we don't emit a store
526 if (!AggregateArgs) ++OAI;
530 // rewrite the original branch instruction with this new target
531 TI->setSuccessor(i, NewTarget);
535 // Now that we've done the deed, simplify the switch instruction.
536 const Type *OldFnRetTy = TheSwitch->getParent()->getParent()->getReturnType();
537 switch (NumExitBlocks) {
539 // There are no successors (the block containing the switch itself), which
540 // means that previously this was the last part of the function, and hence
541 // this should be rewritten as a `ret'
543 // Check if the function should return a value
544 if (OldFnRetTy == Type::VoidTy) {
545 new ReturnInst(0, TheSwitch); // Return void
546 } else if (OldFnRetTy == TheSwitch->getCondition()->getType()) {
547 // return what we have
548 new ReturnInst(TheSwitch->getCondition(), TheSwitch);
550 // Otherwise we must have code extracted an unwind or something, just
551 // return whatever we want.
552 new ReturnInst(Constant::getNullValue(OldFnRetTy), TheSwitch);
555 TheSwitch->getParent()->getInstList().erase(TheSwitch);
558 // Only a single destination, change the switch into an unconditional
560 new BranchInst(TheSwitch->getSuccessor(1), TheSwitch);
561 TheSwitch->getParent()->getInstList().erase(TheSwitch);
564 new BranchInst(TheSwitch->getSuccessor(1), TheSwitch->getSuccessor(2),
566 TheSwitch->getParent()->getInstList().erase(TheSwitch);
569 // Otherwise, make the default destination of the switch instruction be one
570 // of the other successors.
571 TheSwitch->setOperand(0, call);
572 TheSwitch->setSuccessor(0, TheSwitch->getSuccessor(NumExitBlocks));
573 TheSwitch->removeCase(NumExitBlocks); // Remove redundant case
578 void CodeExtractor::moveCodeToFunction(Function *newFunction) {
579 Function *oldFunc = (*BlocksToExtract.begin())->getParent();
580 Function::BasicBlockListType &oldBlocks = oldFunc->getBasicBlockList();
581 Function::BasicBlockListType &newBlocks = newFunction->getBasicBlockList();
583 for (std::set<BasicBlock*>::const_iterator i = BlocksToExtract.begin(),
584 e = BlocksToExtract.end(); i != e; ++i) {
585 // Delete the basic block from the old function, and the list of blocks
586 oldBlocks.remove(*i);
588 // Insert this basic block into the new function
589 newBlocks.push_back(*i);
593 /// ExtractRegion - Removes a loop from a function, replaces it with a call to
594 /// new function. Returns pointer to the new function.
598 /// find inputs and outputs for the region
600 /// for inputs: add to function as args, map input instr* to arg#
601 /// for outputs: add allocas for scalars,
602 /// add to func as args, map output instr* to arg#
604 /// rewrite func to use argument #s instead of instr*
606 /// for each scalar output in the function: at every exit, store intermediate
607 /// computed result back into memory.
609 Function *CodeExtractor::
610 ExtractCodeRegion(const std::vector<BasicBlock*> &code) {
611 if (!isEligible(code))
614 // 1) Find inputs, outputs
615 // 2) Construct new function
616 // * Add allocas for defs, pass as args by reference
617 // * Pass in uses as args
618 // 3) Move code region, add call instr to func
620 BlocksToExtract.insert(code.begin(), code.end());
622 Values inputs, outputs;
624 // Assumption: this is a single-entry code region, and the header is the first
625 // block in the region.
626 BasicBlock *header = code[0];
628 for (unsigned i = 1, e = code.size(); i != e; ++i)
629 for (pred_iterator PI = pred_begin(code[i]), E = pred_end(code[i]);
631 assert(BlocksToExtract.count(*PI) &&
632 "No blocks in this region may have entries from outside the region"
633 " except for the first block!");
635 // If we have to split PHI nodes or the entry block, do so now.
636 severSplitPHINodes(header);
638 // If we have any return instructions in the region, split those blocks so
639 // that the return is not in the region.
642 Function *oldFunction = header->getParent();
644 // This takes place of the original loop
645 BasicBlock *codeReplacer = new BasicBlock("codeRepl", oldFunction, header);
647 // The new function needs a root node because other nodes can branch to the
648 // head of the region, but the entry node of a function cannot have preds.
649 BasicBlock *newFuncRoot = new BasicBlock("newFuncRoot");
650 newFuncRoot->getInstList().push_back(new BranchInst(header));
652 // Find inputs to, outputs from the code region.
653 findInputsOutputs(inputs, outputs);
655 // Construct new function based on inputs/outputs & add allocas for all defs.
656 Function *newFunction = constructFunction(inputs, outputs, header,
658 codeReplacer, oldFunction,
659 oldFunction->getParent());
661 emitCallAndSwitchStatement(newFunction, codeReplacer, inputs, outputs);
663 moveCodeToFunction(newFunction);
665 // Loop over all of the PHI nodes in the header block, and change any
666 // references to the old incoming edge to be the new incoming edge.
667 for (BasicBlock::iterator I = header->begin(); isa<PHINode>(I); ++I) {
668 PHINode *PN = cast<PHINode>(I);
669 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
670 if (!BlocksToExtract.count(PN->getIncomingBlock(i)))
671 PN->setIncomingBlock(i, newFuncRoot);
674 // Look at all successors of the codeReplacer block. If any of these blocks
675 // had PHI nodes in them, we need to update the "from" block to be the code
676 // replacer, not the original block in the extracted region.
677 std::vector<BasicBlock*> Succs(succ_begin(codeReplacer),
678 succ_end(codeReplacer));
679 for (unsigned i = 0, e = Succs.size(); i != e; ++i)
680 for (BasicBlock::iterator I = Succs[i]->begin(); isa<PHINode>(I); ++I) {
681 PHINode *PN = cast<PHINode>(I);
682 std::set<BasicBlock*> ProcessedPreds;
683 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
684 if (BlocksToExtract.count(PN->getIncomingBlock(i)))
685 if (ProcessedPreds.insert(PN->getIncomingBlock(i)).second)
686 PN->setIncomingBlock(i, codeReplacer);
688 // There were multiple entries in the PHI for this block, now there
689 // is only one, so remove the duplicated entries.
690 PN->removeIncomingValue(i, false);
695 //cerr << "NEW FUNCTION: " << *newFunction;
696 // verifyFunction(*newFunction);
698 // cerr << "OLD FUNCTION: " << *oldFunction;
699 // verifyFunction(*oldFunction);
701 DEBUG(if (verifyFunction(*newFunction)) abort());
705 bool CodeExtractor::isEligible(const std::vector<BasicBlock*> &code) {
706 // Deny code region if it contains allocas or vastarts.
707 for (std::vector<BasicBlock*>::const_iterator BB = code.begin(), e=code.end();
709 for (BasicBlock::const_iterator I = (*BB)->begin(), Ie = (*BB)->end();
711 if (isa<AllocaInst>(*I))
713 else if (const CallInst *CI = dyn_cast<CallInst>(I))
714 if (const Function *F = CI->getCalledFunction())
715 if (F->getIntrinsicID() == Intrinsic::vastart)
721 /// ExtractCodeRegion - slurp a sequence of basic blocks into a brand new
724 Function* llvm::ExtractCodeRegion(DominatorTree &DT,
725 const std::vector<BasicBlock*> &code,
726 bool AggregateArgs) {
727 return CodeExtractor(&DT, AggregateArgs).ExtractCodeRegion(code);
730 /// ExtractBasicBlock - slurp a natural loop into a brand new function
732 Function* llvm::ExtractLoop(DominatorTree &DT, Loop *L, bool AggregateArgs) {
733 return CodeExtractor(&DT, AggregateArgs).ExtractCodeRegion(L->getBlocks());
736 /// ExtractBasicBlock - slurp a basic block into a brand new function
738 Function* llvm::ExtractBasicBlock(BasicBlock *BB, bool AggregateArgs) {
739 std::vector<BasicBlock*> Blocks;
740 Blocks.push_back(BB);
741 return CodeExtractor(0, AggregateArgs).ExtractCodeRegion(Blocks);