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