//===- CodeExtractor.cpp - Pull code region into a new function -----------===//
-//
+//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
+//
//===----------------------------------------------------------------------===//
//
// This file implements the interface to tear out a code region, such as an
#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 "Support/CommandLine.h"
-#include "Support/Debug.h"
-#include "Support/StringExtras.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/ADT/StringExtras.h"
#include <algorithm>
#include <set>
+#include <iostream>
using namespace llvm;
// Provide a command-line option to aggregate function arguments into a struct
std::set<BasicBlock*> BlocksToExtract;
DominatorSet *DS;
bool AggregateArgs;
+ unsigned NumExitBlocks;
+ const Type *RetTy;
public:
CodeExtractor(DominatorSet *ds = 0, bool AggArgs = false)
- : DS(ds), AggregateArgs(AggregateArgsOpt) {}
+ : DS(ds), AggregateArgs(AggArgs||AggregateArgsOpt), NumExitBlocks(~0U) {}
Function *ExtractCodeRegion(const std::vector<BasicBlock*> &code);
bool isEligible(const std::vector<BasicBlock*> &code);
private:
- void findInputsOutputs(Values &inputs, Values &outputs,
- BasicBlock *newHeader,
- BasicBlock *newRootNode);
+ /// definedInRegion - Return true if the specified value is defined in the
+ /// extracted region.
+ bool definedInRegion(Value *V) const {
+ if (Instruction *I = dyn_cast<Instruction>(V))
+ if (BlocksToExtract.count(I->getParent()))
+ return true;
+ return false;
+ }
+
+ /// definedInCaller - Return true if the specified value is defined in the
+ /// function being code extracted, but not in the region being extracted.
+ /// These values must be passed in as live-ins to the function.
+ 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,
};
}
-void CodeExtractor::findInputsOutputs(Values &inputs, Values &outputs,
- BasicBlock *newHeader,
- BasicBlock *newRootNode) {
- for (std::set<BasicBlock*>::const_iterator ci = BlocksToExtract.begin(),
+/// severSplitPHINodes - If a PHI node has multiple inputs from outside of the
+/// region, we need to split the entry block of the region so that the PHI node
+/// is easier to deal with.
+void CodeExtractor::severSplitPHINodes(BasicBlock *&Header) {
+ bool HasPredsFromRegion = false;
+ unsigned NumPredsOutsideRegion = 0;
+
+ if (Header != &Header->getParent()->front()) {
+ PHINode *PN = dyn_cast<PHINode>(Header->begin());
+ if (!PN) return; // No PHI nodes.
+
+ // If the header node contains any PHI nodes, check to see if there is more
+ // than one entry from outside the region. If so, we need to sever the
+ // header block into two.
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+ if (BlocksToExtract.count(PN->getIncomingBlock(i)))
+ HasPredsFromRegion = true;
+ else
+ ++NumPredsOutsideRegion;
+
+ // If there is one (or fewer) predecessor from outside the region, we don't
+ // need to do anything special.
+ if (NumPredsOutsideRegion <= 1) return;
+ }
+
+ // Otherwise, we need to split the header block into two pieces: one
+ // containing PHI nodes merging values from outside of the region, and a
+ // second that contains all of the code for the block and merges back any
+ // incoming values from inside of the region.
+ BasicBlock::iterator AfterPHIs = Header->begin();
+ while (isa<PHINode>(AfterPHIs)) ++AfterPHIs;
+ BasicBlock *NewBB = Header->splitBasicBlock(AfterPHIs,
+ Header->getName()+".ce");
+
+ // We only want to code extract the second block now, and it becomes the new
+ // header of the region.
+ BasicBlock *OldPred = Header;
+ BlocksToExtract.erase(OldPred);
+ BlocksToExtract.insert(NewBB);
+ Header = NewBB;
+
+ // Okay, update dominator sets. The blocks that dominate the new one are the
+ // blocks that dominate TIBB plus the new block itself.
+ if (DS) {
+ DominatorSet::DomSetType DomSet = DS->getDominators(OldPred);
+ DomSet.insert(NewBB); // A block always dominates itself.
+ DS->addBasicBlock(NewBB, DomSet);
+
+ // Additionally, NewBB dominates all blocks in the function that are
+ // dominated by OldPred.
+ Function *F = Header->getParent();
+ for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I)
+ if (DS->properlyDominates(OldPred, I))
+ DS->addDominator(I, NewBB);
+ }
+
+ // Okay, now we need to adjust the PHI nodes and any branches from within the
+ // region to go to the new header block instead of the old header block.
+ if (HasPredsFromRegion) {
+ PHINode *PN = cast<PHINode>(OldPred->begin());
+ // Loop over all of the predecessors of OldPred that are in the region,
+ // changing them to branch to NewBB instead.
+ 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);
+ }
+
+ // Okay, everthing within the region is now branching to the right block, we
+ // just have to update the PHI nodes now, inserting PHI nodes into NewBB.
+ for (AfterPHIs = OldPred->begin(); isa<PHINode>(AfterPHIs); ++AfterPHIs) {
+ PHINode *PN = cast<PHINode>(AfterPHIs);
+ // Create a new PHI node in the new region, which has an incoming value
+ // from OldPred of PN.
+ PHINode *NewPN = new PHINode(PN->getType(), PN->getName()+".ce",
+ NewBB->begin());
+ NewPN->addIncoming(PN, OldPred);
+
+ // Loop over all of the incoming value in PN, moving them to NewPN if they
+ // are from the extracted region.
+ 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");
+}
+
+// findInputsOutputs - Find inputs to, outputs from the code region.
+//
+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) {
// 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 *PN = dyn_cast<PHINode>(I)) {
- for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
- Value *V = PN->getIncomingValue(i);
- if (!BlocksToExtract.count(PN->getIncomingBlock(i)) &&
- (isa<Instruction>(V) || isa<Argument>(V)))
- inputs.push_back(V);
- else if (Instruction *opI = dyn_cast<Instruction>(V)) {
- if (!BlocksToExtract.count(opI->getParent()))
- inputs.push_back(opI);
- } else if (isa<Argument>(V))
- inputs.push_back(V);
- }
- } else {
- // All other instructions go through the generic input finder
- // Loop over the operands of each instruction (inputs)
- for (User::op_iterator op = I->op_begin(), opE = I->op_end();
- op != opE; ++op)
- if (Instruction *opI = dyn_cast<Instruction>(*op)) {
- // Check if definition of this operand is within the loop
- if (!BlocksToExtract.count(opI->getParent()))
- inputs.push_back(opI);
- } else if (isa<Argument>(*op)) {
- inputs.push_back(*op);
- }
- }
-
- // Consider uses of this instruction (outputs)
+ for (User::op_iterator O = I->op_begin(), E = I->op_end(); O != E; ++O)
+ if (definedInCaller(*O))
+ inputs.push_back(*O);
+
+ // Consider uses of this instruction (outputs).
for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
UI != E; ++UI)
- if (!BlocksToExtract.count(cast<Instruction>(*UI)->getParent())) {
+ if (!definedInRegion(*UI)) {
outputs.push_back(I);
break;
}
} // for: insts
+
+ // Keep track of the exit blocks from the region.
+ 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));
} // for: basic blocks
+
+ NumExitBlocks = ExitBlocks.size();
+
+ // Eliminate duplicates.
+ 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());
}
/// constructFunction - make a function based on inputs and outputs, as follows:
DEBUG(std::cerr << "outputs: " << outputs.size() << "\n");
// This function returns unsigned, outputs will go back by reference.
- Type *retTy = Type::UShortTy;
+ switch (NumExitBlocks) {
+ case 0:
+ case 1: RetTy = Type::VoidTy; break;
+ case 2: RetTy = Type::BoolTy; break;
+ default: RetTy = Type::UShortTy; break;
+ }
+
std::vector<const Type*> paramTy;
// Add the types of the input values to the function's argument list
for (Values::const_iterator i = inputs.begin(),
e = inputs.end(); i != e; ++i) {
const Value *value = *i;
- DEBUG(std::cerr << "value used in func: " << value << "\n");
+ DEBUG(std::cerr << "value used in func: " << *value << "\n");
paramTy.push_back(value->getType());
}
// Add the types of the output values to the function's argument list.
for (Values::const_iterator I = outputs.begin(), E = outputs.end();
I != E; ++I) {
- DEBUG(std::cerr << "instr used in func: " << *I << "\n");
+ DEBUG(std::cerr << "instr used in func: " << **I << "\n");
if (AggregateArgs)
paramTy.push_back((*I)->getType());
else
paramTy.push_back(PointerType::get((*I)->getType()));
}
- DEBUG(std::cerr << "Function type: " << retTy << " f(");
+ DEBUG(std::cerr << "Function type: " << *RetTy << " f(");
DEBUG(for (std::vector<const Type*>::iterator i = paramTy.begin(),
- e = paramTy.end(); i != e; ++i) std::cerr << *i << ", ");
+ e = paramTy.end(); i != e; ++i) std::cerr << **i << ", ");
DEBUG(std::cerr << ")\n");
if (AggregateArgs && (inputs.size() + outputs.size() > 0)) {
paramTy.clear();
paramTy.push_back(StructPtr);
}
- const FunctionType *funcType = FunctionType::get(retTy, paramTy, false);
+ const FunctionType *funcType = FunctionType::get(RetTy, paramTy, false);
// Create the new function
Function *newFunction = new Function(funcType,
GlobalValue::InternalLinkage,
- oldFunction->getName() + "_code", M);
+ oldFunction->getName() + "_" +
+ header->getName(), M);
newFunction->getBasicBlockList().push_back(newRootNode);
// Create an iterator to name all of the arguments we inserted.
- Function::aiterator AI = newFunction->abegin();
+ Function::arg_iterator AI = newFunction->arg_begin();
// Rewrite all users of the inputs in the extracted region to use the
// arguments (or appropriate addressing into struct) instead.
if (AggregateArgs) {
std::vector<Value*> Indices;
Indices.push_back(Constant::getNullValue(Type::UIntTy));
- Indices.push_back(ConstantUInt::get(Type::UIntTy, i));
+ Indices.push_back(ConstantInt::get(Type::UIntTy, i));
std::string GEPname = "gep_" + inputs[i]->getName();
TerminatorInst *TI = newFunction->begin()->getTerminator();
GetElementPtrInst *GEP = new GetElementPtrInst(AI, Indices, GEPname, TI);
// Set names for input and output arguments.
if (!AggregateArgs) {
- AI = newFunction->abegin();
+ 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");
+ AI->setName(outputs[i]->getName()+".out");
}
// Rewrite branches to basic blocks outside of the loop to new dummy blocks
return newFunction;
}
-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) {
- // Delete the basic block from the old function, and the list of blocks
- oldBlocks.remove(*i);
-
- // Insert this basic block into the new function
- newBlocks.push_back(*i);
- }
-}
-
-void
-CodeExtractor::emitCallAndSwitchStatement(Function *newFunction,
- BasicBlock *codeReplacer,
- Values &inputs,
- Values &outputs) {
-
- // Emit a call to the new function, passing in:
- // *pointer to struct (if aggregating parameters), or
- // plan inputs and allocated memory for outputs
+/// emitCallAndSwitchStatement - This method sets up the caller side by adding
+/// the call instruction, splitting any PHI nodes in the header block as
+/// necessary.
+void CodeExtractor::
+emitCallAndSwitchStatement(Function *newFunction, BasicBlock *codeReplacer,
+ Values &inputs, Values &outputs) {
+ // Emit a call to the new function, passing in: *pointer to struct (if
+ // aggregating parameters), or plan inputs and allocated memory for outputs
std::vector<Value*> params, StructValues, ReloadOutputs;
// Add inputs as params, or to be filled into the struct
// Allocate a struct at the beginning of this function
Type *StructArgTy = StructType::get(ArgTypes);
- Struct =
- new AllocaInst(StructArgTy, 0, "structArg",
+ Struct =
+ new AllocaInst(StructArgTy, 0, "structArg",
codeReplacer->getParent()->begin()->begin());
params.push_back(Struct);
for (unsigned i = 0, e = inputs.size(); i != e; ++i) {
std::vector<Value*> Indices;
Indices.push_back(Constant::getNullValue(Type::UIntTy));
- Indices.push_back(ConstantUInt::get(Type::UIntTy, i));
+ Indices.push_back(ConstantInt::get(Type::UIntTy, i));
GetElementPtrInst *GEP =
new GetElementPtrInst(Struct, Indices,
- "gep_" + StructValues[i]->getName(), 0);
+ "gep_" + StructValues[i]->getName());
codeReplacer->getInstList().push_back(GEP);
StoreInst *SI = new StoreInst(StructValues[i], GEP);
codeReplacer->getInstList().push_back(SI);
}
- }
+ }
// Emit the call to the function
- CallInst *call = new CallInst(newFunction, params, "targetBlock");
+ CallInst *call = new CallInst(newFunction, params,
+ NumExitBlocks > 1 ? "targetBlock" : "");
codeReplacer->getInstList().push_back(call);
- Function::aiterator OutputArgBegin = newFunction->abegin();
+ Function::arg_iterator OutputArgBegin = newFunction->arg_begin();
unsigned FirstOut = inputs.size();
if (!AggregateArgs)
std::advance(OutputArgBegin, inputs.size());
if (AggregateArgs) {
std::vector<Value*> Indices;
Indices.push_back(Constant::getNullValue(Type::UIntTy));
- Indices.push_back(ConstantUInt::get(Type::UIntTy, FirstOut + i));
- GetElementPtrInst *GEP
+ Indices.push_back(ConstantInt::get(Type::UIntTy, FirstOut + i));
+ GetElementPtrInst *GEP
= new GetElementPtrInst(Struct, Indices,
- "gep_reload_" + outputs[i]->getName(), 0);
+ "gep_reload_" + outputs[i]->getName());
codeReplacer->getInstList().push_back(GEP);
Output = GEP;
} else {
}
// Now we can emit a switch statement using the call as a value.
- SwitchInst *TheSwitch = new SwitchInst(call, codeReplacer, codeReplacer);
+ SwitchInst *TheSwitch =
+ new SwitchInst(ConstantInt::getNullValue(Type::UShortTy),
+ codeReplacer, 0, codeReplacer);
// Since there may be multiple exits from the original region, make the new
// function return an unsigned, switch on that number. This loop iterates
// destination, create one now!
NewTarget = new BasicBlock(OldTarget->getName() + ".exitStub",
newFunction);
+ unsigned SuccNum = switchVal++;
+
+ Value *brVal = 0;
+ switch (NumExitBlocks) {
+ case 0:
+ case 1: break; // No value needed.
+ case 2: // Conditional branch, return a bool
+ brVal = ConstantBool::get(!SuccNum);
+ break;
+ default:
+ brVal = ConstantInt::get(Type::UShortTy, SuccNum);
+ break;
+ }
- ConstantUInt *brVal = ConstantUInt::get(Type::UShortTy, switchVal++);
ReturnInst *NTRet = new ReturnInst(brVal, NewTarget);
// Update the switch instruction.
- TheSwitch->addCase(brVal, OldTarget);
+ TheSwitch->addCase(ConstantInt::get(Type::UShortTy, SuccNum),
+ OldTarget);
// Restore values just before we exit
- Function::aiterator OAI = OutputArgBegin;
+ Function::arg_iterator OAI = OutputArgBegin;
for (unsigned out = 0, e = outputs.size(); out != e; ++out) {
// For an invoke, the normal destination is the only one that is
// dominated by the result of the invocation
BasicBlock *DefBlock = cast<Instruction>(outputs[out])->getParent();
- if (InvokeInst *Invoke = dyn_cast<InvokeInst>(outputs[out]))
+
+ bool DominatesDef = true;
+
+ if (InvokeInst *Invoke = dyn_cast<InvokeInst>(outputs[out])) {
DefBlock = Invoke->getNormalDest();
- if (!DS || DS->dominates(DefBlock, TI->getParent()))
+
+ // Make sure we are looking at the original successor block, not
+ // at a newly inserted exit block, which won't be in the dominator
+ // info.
+ for (std::map<BasicBlock*, BasicBlock*>::iterator I =
+ ExitBlockMap.begin(), E = ExitBlockMap.end(); I != E; ++I)
+ if (DefBlock == I->second) {
+ DefBlock = I->first;
+ break;
+ }
+
+ // In the extract block case, if the block we are extracting ends
+ // with an invoke instruction, make sure that we don't emit a
+ // store of the invoke value for the unwind block.
+ if (!DS && DefBlock != OldTarget)
+ DominatesDef = false;
+ }
+
+ if (DS)
+ DominatesDef = DS->dominates(DefBlock, OldTarget);
+
+ if (DominatesDef) {
if (AggregateArgs) {
std::vector<Value*> Indices;
Indices.push_back(Constant::getNullValue(Type::UIntTy));
- Indices.push_back(ConstantUInt::get(Type::UIntTy,FirstOut+out));
+ Indices.push_back(ConstantInt::get(Type::UIntTy,FirstOut+out));
GetElementPtrInst *GEP =
new GetElementPtrInst(OAI, Indices,
- "gep_" + outputs[out]->getName(),
+ "gep_" + outputs[out]->getName(),
NTRet);
new StoreInst(outputs[out], GEP, NTRet);
- } else
+ } else {
new StoreInst(outputs[out], OAI, NTRet);
+ }
+ }
// Advance output iterator even if we don't emit a store
if (!AggregateArgs) ++OAI;
}
}
}
- // Now that we've done the deed, make the default destination of the switch
- // instruction be a block with a call to abort() -- since this path should not
- // be taken, this will abort sooner rather than later.
- if (TheSwitch->getNumSuccessors() > 1) {
- Function *container = codeReplacer->getParent();
- BasicBlock *abortBB = new BasicBlock("abortBlock", container);
- std::vector<const Type*> paramTypes;
- FunctionType *abortTy = FunctionType::get(Type::VoidTy, paramTypes, false);
- Function *abortFunc =
- container->getParent()->getOrInsertFunction("abort", abortTy);
- abortBB->getInstList().push_back(new CallInst(abortFunc));
- Function *ParentFunc = TheSwitch->getParent()->getParent();
- if (ParentFunc->getReturnType() == Type::VoidTy)
- new ReturnInst(0, abortBB);
- else
- new ReturnInst(Constant::getNullValue(ParentFunc->getReturnType()),
- abortBB);
- TheSwitch->setSuccessor(0, abortBB);
- } else {
- // There is only 1 successor (the block containing the switch itself), which
+ // Now that we've done the deed, simplify the switch instruction.
+ const Type *OldFnRetTy = TheSwitch->getParent()->getParent()->getReturnType();
+ switch (NumExitBlocks) {
+ case 0:
+ // There are no successors (the block containing the switch itself), which
// means that previously this was the last part of the function, and hence
// this should be rewritten as a `ret'
-
+
// Check if the function should return a value
- if (TheSwitch->getParent()->getParent()->getReturnType() != Type::VoidTy &&
- TheSwitch->getParent()->getParent()->getReturnType() ==
- TheSwitch->getCondition()->getType())
+ if (OldFnRetTy == Type::VoidTy) {
+ new ReturnInst(0, TheSwitch); // Return void
+ } else if (OldFnRetTy == TheSwitch->getCondition()->getType()) {
// return what we have
new ReturnInst(TheSwitch->getCondition(), TheSwitch);
- else
- // just return
- new ReturnInst(0, TheSwitch);
+ } else {
+ // Otherwise we must have code extracted an unwind or something, just
+ // return whatever we want.
+ new ReturnInst(Constant::getNullValue(OldFnRetTy), TheSwitch);
+ }
TheSwitch->getParent()->getInstList().erase(TheSwitch);
+ break;
+ case 1:
+ // Only a single destination, change the switch into an unconditional
+ // branch.
+ new BranchInst(TheSwitch->getSuccessor(1), TheSwitch);
+ TheSwitch->getParent()->getInstList().erase(TheSwitch);
+ break;
+ case 2:
+ new BranchInst(TheSwitch->getSuccessor(1), TheSwitch->getSuccessor(2),
+ call, TheSwitch);
+ TheSwitch->getParent()->getInstList().erase(TheSwitch);
+ break;
+ default:
+ // Otherwise, make the default destination of the switch instruction be one
+ // of the other successors.
+ TheSwitch->setOperand(0, call);
+ TheSwitch->setSuccessor(0, TheSwitch->getSuccessor(NumExitBlocks));
+ TheSwitch->removeCase(NumExitBlocks); // Remove redundant case
+ 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) {
+ // Delete the basic block from the old function, and the list of blocks
+ oldBlocks.remove(*i);
+
+ // Insert this basic block into the new function
+ newBlocks.push_back(*i);
+ }
+}
/// ExtractRegion - Removes a loop from a function, replaces it with a call to
/// new function. Returns pointer to the new function.
///
/// find inputs and outputs for the region
///
-/// for inputs: add to function as args, map input instr* to arg#
-/// for outputs: add allocas for scalars,
+/// for inputs: add to function as args, map input instr* to arg#
+/// for outputs: add allocas for scalars,
/// add to func as args, map output instr* to arg#
///
/// rewrite func to use argument #s instead of instr*
///
-/// for each scalar output in the function: at every exit, store intermediate
+/// for each scalar output in the function: at every exit, store intermediate
/// computed result back into memory.
///
-Function *CodeExtractor::ExtractCodeRegion(const std::vector<BasicBlock*> &code)
-{
+Function *CodeExtractor::
+ExtractCodeRegion(const std::vector<BasicBlock*> &code) {
if (!isEligible(code))
return 0;
// Assumption: this is a single-entry code region, and the header is the first
// block in the region.
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!");
-
+
+ // If we have to split PHI nodes or the entry block, do so now.
+ severSplitPHINodes(header);
+
+ // If we have any return instructions in the region, split those blocks so
+ // that the return is not in the region.
+ splitReturnBlocks();
+
Function *oldFunction = header->getParent();
// This takes place of the original loop
- BasicBlock *codeReplacer = new BasicBlock("codeRepl", oldFunction);
+ BasicBlock *codeReplacer = new BasicBlock("codeRepl", oldFunction, header);
// The new function needs a root node because other nodes can branch to the
- // head of the loop, and the root cannot have predecessors
+ // head of the region, but the entry node of a function cannot have preds.
BasicBlock *newFuncRoot = new BasicBlock("newFuncRoot");
newFuncRoot->getInstList().push_back(new BranchInst(header));
- // Find inputs to, outputs from the code region
- //
- // If one of the inputs is coming from a different basic block and it's in a
- // phi node, we need to rewrite the phi node:
- //
- // * All the inputs which involve basic blocks OUTSIDE of this region go into
- // a NEW phi node that takes care of finding which value really came in.
- // The result of this phi is passed to the function as an argument.
- //
- // * All the other phi values stay.
- //
- // FIXME: PHI nodes' incoming blocks aren't being rewritten to accomodate for
- // blocks moving to a new function.
- // SOLUTION: move Phi nodes out of the loop header into the codeReplacer, pass
- // the values as parameters to the function
- findInputsOutputs(inputs, outputs, codeReplacer, newFuncRoot);
-
- // Step 2: Construct new function based on inputs/outputs,
- // Add allocas for all defs
- Function *newFunction = constructFunction(inputs, outputs, code[0],
- newFuncRoot,
+ // Find inputs to, outputs from the code region.
+ findInputsOutputs(inputs, outputs);
+
+ // Construct new function based on inputs/outputs & add allocas for all defs.
+ Function *newFunction = constructFunction(inputs, outputs, header,
+ newFuncRoot,
codeReplacer, oldFunction,
oldFunction->getParent());
moveCodeToFunction(newFunction);
- // Loop over all of the PHI nodes in the entry block (code[0]), and change any
+ // Loop over all of the PHI nodes in the header block, 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<PHINode>(I); ++I)
+ 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);
+ }
// Look at all successors of the codeReplacer block. If any of these blocks
// had PHI nodes in them, we need to update the "from" block to be the code
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();
- PHINode *PN = dyn_cast<PHINode>(I); ++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)))
- PN->setIncomingBlock(i, codeReplacer);
-
+ if (ProcessedPreds.insert(PN->getIncomingBlock(i)).second)
+ PN->setIncomingBlock(i, codeReplacer);
+ else {
+ // There were multiple entries in the PHI for this block, now there
+ // is only one, so remove the duplicated entries.
+ PN->removeIncomingValue(i, false);
+ --i; --e;
+ }
+ }
+
+ //std::cerr << "NEW FUNCTION: " << *newFunction;
+ // verifyFunction(*newFunction);
+
+ // std::cerr << "OLD FUNCTION: " << *oldFunction;
+ // verifyFunction(*oldFunction);
DEBUG(if (verifyFunction(*newFunction)) abort());
return newFunction;
}
bool CodeExtractor::isEligible(const std::vector<BasicBlock*> &code) {
- // Deny code region if it contains allocas
+ // Deny code region if it contains allocas or vastarts.
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::ExtractBasicBlock(BasicBlock *BB, bool AggregateArgs) {
std::vector<BasicBlock*> Blocks;
Blocks.push_back(BB);
- return CodeExtractor(0, AggregateArgs).ExtractCodeRegion(Blocks);
+ return CodeExtractor(0, AggregateArgs).ExtractCodeRegion(Blocks);
}
projects / oota-llvm.git / blobdiff