1 //===- CloneTrace.cpp - Clone a trace -------------------------------------===//
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 CloneTrace interface, which is used when writing
11 // runtime optimizations. It takes a vector of basic blocks clones the basic
12 // blocks, removes internal phi nodes, adds it to the same function as the
13 // original (although there is no jump to it) and returns the new vector of
16 //===----------------------------------------------------------------------===//
18 #include "llvm/Transforms/Utils/Cloning.h"
19 #include "llvm/iPHINode.h"
20 #include "llvm/Function.h"
23 //Clones the trace (a vector of basic blocks)
24 std::vector<BasicBlock *>
25 llvm::CloneTrace(const std::vector<BasicBlock*> &origTrace) {
26 std::vector<BasicBlock *> clonedTrace;
27 std::map<const Value*, Value*> ValueMap;
29 //First, loop over all the Basic Blocks in the trace and copy
30 //them using CloneBasicBlock. Also fix the phi nodes during
31 //this loop. To fix the phi nodes, we delete incoming branches
32 //that are not in the trace.
33 for(std::vector<BasicBlock *>::const_iterator T = origTrace.begin(),
34 End = origTrace.end(); T != End; ++T) {
37 BasicBlock *clonedBlock =
38 CloneBasicBlock(*T, ValueMap, ".tr", (*T)->getParent());
40 //Add it to our new trace
41 clonedTrace.push_back(clonedBlock);
43 //Add this new mapping to our Value Map
44 ValueMap[*T] = clonedBlock;
46 //Loop over the phi instructions and delete operands
47 //that are from blocks not in the trace
48 //only do this if we are NOT the first block
49 if(T != origTrace.begin()) {
50 for (BasicBlock::iterator I = clonedBlock->begin();
51 PHINode *PN = dyn_cast<PHINode>(I); ++I) {
52 //get incoming value for the previous BB
53 Value *V = PN->getIncomingValueForBlock(*(T-1));
54 assert(V && "No incoming value from a BasicBlock in our trace!");
56 //remap our phi node to point to incoming value
60 clonedBlock->getInstList().erase(PN);
65 //Second loop to do the remapping
66 for(std::vector<BasicBlock *>::const_iterator BB = clonedTrace.begin(),
67 BE = clonedTrace.end(); BB != BE; ++BB) {
68 for(BasicBlock::iterator I = (*BB)->begin(); I != (*BB)->end(); ++I) {
70 //Loop over all the operands of the instruction
71 for(unsigned op=0, E = I->getNumOperands(); op != E; ++op) {
72 const Value *Op = I->getOperand(op);
74 //Get it out of the value map
75 Value *V = ValueMap[Op];
77 //If not in the value map, then its outside our trace so ignore
84 //return new vector of basic blocks