#include "llvm/Transforms/Utils/FunctionUtils.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
#include "llvm/Intrinsics.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/StringExtras.h"
#include <algorithm>
#include <set>
using namespace llvm;
static cl::opt<bool>
AggregateArgsOpt("aggregate-extracted-args", cl::Hidden,
cl::desc("Aggregate arguments to code-extracted functions"));
namespace {
class VISIBILITY_HIDDEN CodeExtractor {
typedef std::vector<Value*> Values;
std::set<BasicBlock*> BlocksToExtract;
DominatorTree* DT;
bool AggregateArgs;
unsigned NumExitBlocks;
const Type *RetTy;
public:
CodeExtractor(DominatorTree* dt = 0, bool AggArgs = false)
: DT(dt), AggregateArgs(AggArgs||AggregateArgsOpt), NumExitBlocks(~0U) {}
Function *ExtractCodeRegion(const std::vector<BasicBlock*> &code);
bool isEligible(const std::vector<BasicBlock*> &code);
private:
bool definedInRegion(Value *V) const {
if (Instruction *I = dyn_cast<Instruction>(V))
if (BlocksToExtract.count(I->getParent()))
return true;
return false;
}
bool definedInCaller(Value *V) const {
if (isa<Argument>(V)) return true;
if (Instruction *I = dyn_cast<Instruction>(V))
if (!BlocksToExtract.count(I->getParent()))
return true;
return false;
}
void severSplitPHINodes(BasicBlock *&Header);
void splitReturnBlocks();
void findInputsOutputs(Values &inputs, Values &outputs);
Function *constructFunction(const Values &inputs,
const Values &outputs,
BasicBlock *header,
BasicBlock *newRootNode, BasicBlock *newHeader,
Function *oldFunction, Module *M);
void moveCodeToFunction(Function *newFunction);
void emitCallAndSwitchStatement(Function *newFunction,
BasicBlock *newHeader,
Values &inputs,
Values &outputs);
};
}
void CodeExtractor::severSplitPHINodes(BasicBlock *&Header) {
bool HasPredsFromRegion = false;
unsigned NumPredsOutsideRegion = 0;
if (Header != &Header->getParent()->getEntryBlock()) {
PHINode *PN = dyn_cast<PHINode>(Header->begin());
if (!PN) return;
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
if (BlocksToExtract.count(PN->getIncomingBlock(i)))
HasPredsFromRegion = true;
else
++NumPredsOutsideRegion;
if (NumPredsOutsideRegion <= 1) return;
}
BasicBlock::iterator AfterPHIs = Header->getFirstNonPHI();
BasicBlock *NewBB = Header->splitBasicBlock(AfterPHIs,
Header->getName()+".ce");
BasicBlock *OldPred = Header;
BlocksToExtract.erase(OldPred);
BlocksToExtract.insert(NewBB);
Header = NewBB;
if (DT)
DT->splitBlock(NewBB);
if (HasPredsFromRegion) {
PHINode *PN = cast<PHINode>(OldPred->begin());
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
if (BlocksToExtract.count(PN->getIncomingBlock(i))) {
TerminatorInst *TI = PN->getIncomingBlock(i)->getTerminator();
TI->replaceUsesOfWith(OldPred, NewBB);
}
for (AfterPHIs = OldPred->begin(); isa<PHINode>(AfterPHIs); ++AfterPHIs) {
PHINode *PN = cast<PHINode>(AfterPHIs);
PHINode *NewPN = PHINode::Create(PN->getType(), PN->getName()+".ce",
NewBB->begin());
NewPN->addIncoming(PN, OldPred);
for (unsigned i = 0; i != PN->getNumIncomingValues(); ++i) {
if (BlocksToExtract.count(PN->getIncomingBlock(i))) {
NewPN->addIncoming(PN->getIncomingValue(i), PN->getIncomingBlock(i));
PN->removeIncomingValue(i);
--i;
}
}
}
}
}
void CodeExtractor::splitReturnBlocks() {
for (std::set<BasicBlock*>::iterator I = BlocksToExtract.begin(),
E = BlocksToExtract.end(); I != E; ++I)
if (ReturnInst *RI = dyn_cast<ReturnInst>((*I)->getTerminator()))
(*I)->splitBasicBlock(RI, (*I)->getName()+".ret");
}
void CodeExtractor::findInputsOutputs(Values &inputs, Values &outputs) {
std::set<BasicBlock*> ExitBlocks;
for (std::set<BasicBlock*>::const_iterator ci = BlocksToExtract.begin(),
ce = BlocksToExtract.end(); ci != ce; ++ci) {
BasicBlock *BB = *ci;
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
for (User::op_iterator O = I->op_begin(), E = I->op_end(); O != E; ++O)
if (definedInCaller(*O))
inputs.push_back(*O);
for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
UI != E; ++UI)
if (!definedInRegion(*UI)) {
outputs.push_back(I);
break;
}
}
TerminatorInst *TI = BB->getTerminator();
for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
if (!BlocksToExtract.count(TI->getSuccessor(i)))
ExitBlocks.insert(TI->getSuccessor(i));
}
NumExitBlocks = ExitBlocks.size();
std::sort(inputs.begin(), inputs.end());
inputs.erase(std::unique(inputs.begin(), inputs.end()), inputs.end());
std::sort(outputs.begin(), outputs.end());
outputs.erase(std::unique(outputs.begin(), outputs.end()), outputs.end());
}
Function *CodeExtractor::constructFunction(const Values &inputs,
const Values &outputs,
BasicBlock *header,
BasicBlock *newRootNode,
BasicBlock *newHeader,
Function *oldFunction,
Module *M) {
DOUT << "inputs: " << inputs.size() << "\n";
DOUT << "outputs: " << outputs.size() << "\n";
switch (NumExitBlocks) {
case 0:
case 1: RetTy = Type::VoidTy; break;
case 2: RetTy = Type::Int1Ty; break;
default: RetTy = Type::Int16Ty; break;
}
std::vector<const Type*> paramTy;
for (Values::const_iterator i = inputs.begin(),
e = inputs.end(); i != e; ++i) {
const Value *value = *i;
DOUT << "value used in func: " << *value << "\n";
paramTy.push_back(value->getType());
}
for (Values::const_iterator I = outputs.begin(), E = outputs.end();
I != E; ++I) {
DOUT << "instr used in func: " << **I << "\n";
if (AggregateArgs)
paramTy.push_back((*I)->getType());
else
paramTy.push_back(PointerType::getUnqual((*I)->getType()));
}
DOUT << "Function type: " << *RetTy << " f(";
for (std::vector<const Type*>::iterator i = paramTy.begin(),
e = paramTy.end(); i != e; ++i)
DOUT << **i << ", ";
DOUT << ")\n";
if (AggregateArgs && (inputs.size() + outputs.size() > 0)) {
PointerType *StructPtr = PointerType::getUnqual(StructType::get(paramTy));
paramTy.clear();
paramTy.push_back(StructPtr);
}
const FunctionType *funcType = FunctionType::get(RetTy, paramTy, false);
Function *newFunction = Function::Create(funcType,
GlobalValue::InternalLinkage,
oldFunction->getName() + "_" +
header->getName(), M);
if (oldFunction->doesNotThrow())
newFunction->setDoesNotThrow(true);
newFunction->getBasicBlockList().push_back(newRootNode);
Function::arg_iterator AI = newFunction->arg_begin();
for (unsigned i = 0, e = inputs.size(); i != e; ++i) {
Value *RewriteVal;
if (AggregateArgs) {
Value *Idx[2];
Idx[0] = Constant::getNullValue(Type::Int32Ty);
Idx[1] = ConstantInt::get(Type::Int32Ty, i);
std::string GEPname = "gep_" + inputs[i]->getName();
TerminatorInst *TI = newFunction->begin()->getTerminator();
GetElementPtrInst *GEP = GetElementPtrInst::Create(AI, Idx, Idx+2,
GEPname, TI);
RewriteVal = new LoadInst(GEP, "load" + GEPname, TI);
} else
RewriteVal = AI++;
std::vector<User*> Users(inputs[i]->use_begin(), inputs[i]->use_end());
for (std::vector<User*>::iterator use = Users.begin(), useE = Users.end();
use != useE; ++use)
if (Instruction* inst = dyn_cast<Instruction>(*use))
if (BlocksToExtract.count(inst->getParent()))
inst->replaceUsesOfWith(inputs[i], RewriteVal);
}
if (!AggregateArgs) {
AI = newFunction->arg_begin();
for (unsigned i = 0, e = inputs.size(); i != e; ++i, ++AI)
AI->setName(inputs[i]->getName());
for (unsigned i = 0, e = outputs.size(); i != e; ++i, ++AI)
AI->setName(outputs[i]->getName()+".out");
}
std::vector<User*> Users(header->use_begin(), header->use_end());
for (unsigned i = 0, e = Users.size(); i != e; ++i)
if (TerminatorInst *TI = dyn_cast<TerminatorInst>(Users[i]))
if (!BlocksToExtract.count(TI->getParent()) &&
TI->getParent()->getParent() == oldFunction)
TI->replaceUsesOfWith(header, newHeader);
return newFunction;
}
void CodeExtractor::
emitCallAndSwitchStatement(Function *newFunction, BasicBlock *codeReplacer,
Values &inputs, Values &outputs) {
std::vector<Value*> params, StructValues, ReloadOutputs;
for (Values::iterator i = inputs.begin(), e = inputs.end(); i != e; ++i)
if (AggregateArgs)
StructValues.push_back(*i);
else
params.push_back(*i);
for (Values::iterator i = outputs.begin(), e = outputs.end(); i != e; ++i) {
if (AggregateArgs) {
StructValues.push_back(*i);
} else {
AllocaInst *alloca =
new AllocaInst((*i)->getType(), 0, (*i)->getName()+".loc",
codeReplacer->getParent()->begin()->begin());
ReloadOutputs.push_back(alloca);
params.push_back(alloca);
}
}
AllocaInst *Struct = 0;
if (AggregateArgs && (inputs.size() + outputs.size() > 0)) {
std::vector<const Type*> ArgTypes;
for (Values::iterator v = StructValues.begin(),
ve = StructValues.end(); v != ve; ++v)
ArgTypes.push_back((*v)->getType());
Type *StructArgTy = StructType::get(ArgTypes);
Struct =
new AllocaInst(StructArgTy, 0, "structArg",
codeReplacer->getParent()->begin()->begin());
params.push_back(Struct);
for (unsigned i = 0, e = inputs.size(); i != e; ++i) {
Value *Idx[2];
Idx[0] = Constant::getNullValue(Type::Int32Ty);
Idx[1] = ConstantInt::get(Type::Int32Ty, i);
GetElementPtrInst *GEP =
GetElementPtrInst::Create(Struct, Idx, Idx + 2,
"gep_" + StructValues[i]->getName());
codeReplacer->getInstList().push_back(GEP);
StoreInst *SI = new StoreInst(StructValues[i], GEP);
codeReplacer->getInstList().push_back(SI);
}
}
CallInst *call = CallInst::Create(newFunction, params.begin(), params.end(),
NumExitBlocks > 1 ? "targetBlock" : "");
codeReplacer->getInstList().push_back(call);
Function::arg_iterator OutputArgBegin = newFunction->arg_begin();
unsigned FirstOut = inputs.size();
if (!AggregateArgs)
std::advance(OutputArgBegin, inputs.size());
for (unsigned i = 0, e = outputs.size(); i != e; ++i) {
Value *Output = 0;
if (AggregateArgs) {
Value *Idx[2];
Idx[0] = Constant::getNullValue(Type::Int32Ty);
Idx[1] = ConstantInt::get(Type::Int32Ty, FirstOut + i);
GetElementPtrInst *GEP
= GetElementPtrInst::Create(Struct, Idx, Idx + 2,
"gep_reload_" + outputs[i]->getName());
codeReplacer->getInstList().push_back(GEP);
Output = GEP;
} else {
Output = ReloadOutputs[i];
}
LoadInst *load = new LoadInst(Output, outputs[i]->getName()+".reload");
codeReplacer->getInstList().push_back(load);
std::vector<User*> Users(outputs[i]->use_begin(), outputs[i]->use_end());
for (unsigned u = 0, e = Users.size(); u != e; ++u) {
Instruction *inst = cast<Instruction>(Users[u]);
if (!BlocksToExtract.count(inst->getParent()))
inst->replaceUsesOfWith(outputs[i], load);
}
}
SwitchInst *TheSwitch =
SwitchInst::Create(ConstantInt::getNullValue(Type::Int16Ty),
codeReplacer, 0, codeReplacer);
std::map<BasicBlock*, BasicBlock*> ExitBlockMap;
unsigned switchVal = 0;
for (std::set<BasicBlock*>::const_iterator i = BlocksToExtract.begin(),
e = BlocksToExtract.end(); i != e; ++i) {
TerminatorInst *TI = (*i)->getTerminator();
for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
if (!BlocksToExtract.count(TI->getSuccessor(i))) {
BasicBlock *OldTarget = TI->getSuccessor(i);
BasicBlock *&NewTarget = ExitBlockMap[OldTarget];
if (!NewTarget) {
NewTarget = BasicBlock::Create(OldTarget->getName() + ".exitStub",
newFunction);
unsigned SuccNum = switchVal++;
Value *brVal = 0;
switch (NumExitBlocks) {
case 0:
case 1: break; case 2: brVal = ConstantInt::get(Type::Int1Ty, !SuccNum);
break;
default:
brVal = ConstantInt::get(Type::Int16Ty, SuccNum);
break;
}
ReturnInst *NTRet = ReturnInst::Create(brVal, NewTarget);
TheSwitch->addCase(ConstantInt::get(Type::Int16Ty, SuccNum),
OldTarget);
Function::arg_iterator OAI = OutputArgBegin;
for (unsigned out = 0, e = outputs.size(); out != e; ++out) {
BasicBlock *DefBlock = cast<Instruction>(outputs[out])->getParent();
bool DominatesDef = true;
if (InvokeInst *Invoke = dyn_cast<InvokeInst>(outputs[out])) {
DefBlock = Invoke->getNormalDest();
for (std::map<BasicBlock*, BasicBlock*>::iterator I =
ExitBlockMap.begin(), E = ExitBlockMap.end(); I != E; ++I)
if (DefBlock == I->second) {
DefBlock = I->first;
break;
}
if (!DT && DefBlock != OldTarget)
DominatesDef = false;
}
if (DT)
DominatesDef = DT->dominates(DefBlock, OldTarget);
if (DominatesDef) {
if (AggregateArgs) {
Value *Idx[2];
Idx[0] = Constant::getNullValue(Type::Int32Ty);
Idx[1] = ConstantInt::get(Type::Int32Ty,FirstOut+out);
GetElementPtrInst *GEP =
GetElementPtrInst::Create(OAI, Idx, Idx + 2,
"gep_" + outputs[out]->getName(),
NTRet);
new StoreInst(outputs[out], GEP, NTRet);
} else {
new StoreInst(outputs[out], OAI, NTRet);
}
}
if (!AggregateArgs) ++OAI;
}
}
TI->setSuccessor(i, NewTarget);
}
}
const Type *OldFnRetTy = TheSwitch->getParent()->getParent()->getReturnType();
switch (NumExitBlocks) {
case 0:
if (OldFnRetTy == Type::VoidTy) {
ReturnInst::Create(0, TheSwitch); } else if (OldFnRetTy == TheSwitch->getCondition()->getType()) {
ReturnInst::Create(TheSwitch->getCondition(), TheSwitch);
} else {
ReturnInst::Create(Constant::getNullValue(OldFnRetTy), TheSwitch);
}
TheSwitch->eraseFromParent();
break;
case 1:
BranchInst::Create(TheSwitch->getSuccessor(1), TheSwitch);
TheSwitch->eraseFromParent();
break;
case 2:
BranchInst::Create(TheSwitch->getSuccessor(1), TheSwitch->getSuccessor(2),
call, TheSwitch);
TheSwitch->eraseFromParent();
break;
default:
TheSwitch->setOperand(0, call);
TheSwitch->setSuccessor(0, TheSwitch->getSuccessor(NumExitBlocks));
TheSwitch->removeCase(NumExitBlocks); break;
}
}
void CodeExtractor::moveCodeToFunction(Function *newFunction) {
Function *oldFunc = (*BlocksToExtract.begin())->getParent();
Function::BasicBlockListType &oldBlocks = oldFunc->getBasicBlockList();
Function::BasicBlockListType &newBlocks = newFunction->getBasicBlockList();
for (std::set<BasicBlock*>::const_iterator i = BlocksToExtract.begin(),
e = BlocksToExtract.end(); i != e; ++i) {
oldBlocks.remove(*i);
newBlocks.push_back(*i);
}
}
Function *CodeExtractor::
ExtractCodeRegion(const std::vector<BasicBlock*> &code) {
if (!isEligible(code))
return 0;
BlocksToExtract.insert(code.begin(), code.end());
Values inputs, outputs;
BasicBlock *header = code[0];
for (unsigned i = 1, e = code.size(); i != e; ++i)
for (pred_iterator PI = pred_begin(code[i]), E = pred_end(code[i]);
PI != E; ++PI)
assert(BlocksToExtract.count(*PI) &&
"No blocks in this region may have entries from outside the region"
" except for the first block!");
severSplitPHINodes(header);
splitReturnBlocks();
Function *oldFunction = header->getParent();
BasicBlock *codeReplacer = BasicBlock::Create("codeRepl", oldFunction,
header);
BasicBlock *newFuncRoot = BasicBlock::Create("newFuncRoot");
newFuncRoot->getInstList().push_back(BranchInst::Create(header));
findInputsOutputs(inputs, outputs);
Function *newFunction = constructFunction(inputs, outputs, header,
newFuncRoot,
codeReplacer, oldFunction,
oldFunction->getParent());
emitCallAndSwitchStatement(newFunction, codeReplacer, inputs, outputs);
moveCodeToFunction(newFunction);
for (BasicBlock::iterator I = header->begin(); isa<PHINode>(I); ++I) {
PHINode *PN = cast<PHINode>(I);
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
if (!BlocksToExtract.count(PN->getIncomingBlock(i)))
PN->setIncomingBlock(i, newFuncRoot);
}
std::vector<BasicBlock*> Succs(succ_begin(codeReplacer),
succ_end(codeReplacer));
for (unsigned i = 0, e = Succs.size(); i != e; ++i)
for (BasicBlock::iterator I = Succs[i]->begin(); isa<PHINode>(I); ++I) {
PHINode *PN = cast<PHINode>(I);
std::set<BasicBlock*> ProcessedPreds;
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
if (BlocksToExtract.count(PN->getIncomingBlock(i))) {
if (ProcessedPreds.insert(PN->getIncomingBlock(i)).second)
PN->setIncomingBlock(i, codeReplacer);
else {
PN->removeIncomingValue(i, false);
--i; --e;
}
}
}
DEBUG(if (verifyFunction(*newFunction)) abort());
return newFunction;
}
bool CodeExtractor::isEligible(const std::vector<BasicBlock*> &code) {
for (std::vector<BasicBlock*>::const_iterator BB = code.begin(), e=code.end();
BB != e; ++BB)
for (BasicBlock::const_iterator I = (*BB)->begin(), Ie = (*BB)->end();
I != Ie; ++I)
if (isa<AllocaInst>(*I))
return false;
else if (const CallInst *CI = dyn_cast<CallInst>(I))
if (const Function *F = CI->getCalledFunction())
if (F->getIntrinsicID() == Intrinsic::vastart)
return false;
return true;
}
Function* llvm::ExtractCodeRegion(DominatorTree &DT,
const std::vector<BasicBlock*> &code,
bool AggregateArgs) {
return CodeExtractor(&DT, AggregateArgs).ExtractCodeRegion(code);
}
Function* llvm::ExtractLoop(DominatorTree &DT, Loop *L, bool AggregateArgs) {
return CodeExtractor(&DT, AggregateArgs).ExtractCodeRegion(L->getBlocks());
}
Function* llvm::ExtractBasicBlock(BasicBlock *BB, bool AggregateArgs) {
std::vector<BasicBlock*> Blocks;
Blocks.push_back(BB);
return CodeExtractor(0, AggregateArgs).ExtractCodeRegion(Blocks);
}