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//===- CloneTrace.cpp - Clone a trace -------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the CloneTrace interface, which is used when writing
// runtime optimizations. It takes a vector of basic blocks clones the basic
// blocks, removes internal phi nodes, adds it to the same function as the
// original (although there is no jump to it) and returns the new vector of
// basic blocks.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/Trace.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Instructions.h"
#include "llvm/Function.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
using namespace llvm;
//Clones the trace (a vector of basic blocks)
std::vector<BasicBlock *>
llvm::CloneTrace(const std::vector<BasicBlock*> &origTrace) {
std::vector<BasicBlock *> clonedTrace;
DenseMap<const Value*, Value*> ValueMap;
//First, loop over all the Basic Blocks in the trace and copy
//them using CloneBasicBlock. Also fix the phi nodes during
//this loop. To fix the phi nodes, we delete incoming branches
//that are not in the trace.
for (std::vector<BasicBlock *>::const_iterator T = origTrace.begin(),
End = origTrace.end(); T != End; ++T) {
//Clone Basic Block
BasicBlock *clonedBlock =
CloneBasicBlock(*T, ValueMap, ".tr", (*T)->getParent());
//Add it to our new trace
clonedTrace.push_back(clonedBlock);
//Add this new mapping to our Value Map
ValueMap[*T] = clonedBlock;
//Loop over the phi instructions and delete operands
//that are from blocks not in the trace
//only do this if we are NOT the first block
if (T != origTrace.begin()) {
for (BasicBlock::iterator I = clonedBlock->begin();
isa<PHINode>(I); ++I) {
PHINode *PN = cast<PHINode>(I);
//get incoming value for the previous BB
Value *V = PN->getIncomingValueForBlock(*(T-1));
assert(V && "No incoming value from a BasicBlock in our trace!");
//remap our phi node to point to incoming value
ValueMap[*&I] = V;
//remove phi node
clonedBlock->getInstList().erase(PN);
}
}
}
//Second loop to do the remapping
for (std::vector<BasicBlock *>::const_iterator BB = clonedTrace.begin(),
BE = clonedTrace.end(); BB != BE; ++BB) {
for (BasicBlock::iterator I = (*BB)->begin(); I != (*BB)->end(); ++I) {
//Loop over all the operands of the instruction
for (unsigned op=0, E = I->getNumOperands(); op != E; ++op) {
const Value *Op = I->getOperand(op);
//Get it out of the value map
Value *V = ValueMap[Op];
//If not in the value map, then its outside our trace so ignore
if (V != 0)
I->setOperand(op,V);
}
}
}
//return new vector of basic blocks
return clonedTrace;
}
/// CloneTraceInto - Clone T into NewFunc. Original<->clone mapping is
/// saved in ValueMap.
///
void llvm::CloneTraceInto(Function *NewFunc, Trace &T,
DenseMap<const Value*, Value*> &ValueMap,
const char *NameSuffix) {
assert(NameSuffix && "NameSuffix cannot be null!");
// Loop over all of the basic blocks in the trace, cloning them as
// appropriate.
//
for (Trace::const_iterator BI = T.begin(), BE = T.end(); BI != BE; ++BI) {
const BasicBlock *BB = *BI;
// Create a new basic block and copy instructions into it!
BasicBlock *CBB = CloneBasicBlock(BB, ValueMap, NameSuffix, NewFunc);
ValueMap[BB] = CBB; // Add basic block mapping.
}
// Loop over all of the instructions in the new function, fixing up operand
// references as we go. This uses ValueMap to do all the hard work.
//
for (Function::iterator BB =
cast<BasicBlock>(ValueMap[T.getEntryBasicBlock()]),
BE = NewFunc->end(); BB != BE; ++BB)
// Loop over all instructions, fixing each one as we find it...
for (BasicBlock::iterator II = BB->begin(); II != BB->end(); ++II)
RemapInstruction(II, ValueMap);
}
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