/3rd_party/llvm/lib/Transforms/Utils/Mem2Reg.cpp
https://code.google.com/p/softart/ · C++ · 90 lines · 53 code · 16 blank · 21 comment · 6 complexity · c4cbc8771306e0fa79e9ccf59413103d MD5 · raw file
- //===- Mem2Reg.cpp - The -mem2reg pass, a wrapper around the Utils lib ----===//
- //
- // The LLVM Compiler Infrastructure
- //
- // This file is distributed under the University of Illinois Open Source
- // License. See LICENSE.TXT for details.
- //
- //===----------------------------------------------------------------------===//
- //
- // This pass is a simple pass wrapper around the PromoteMemToReg function call
- // exposed by the Utils library.
- //
- //===----------------------------------------------------------------------===//
- #define DEBUG_TYPE "mem2reg"
- #include "llvm/Transforms/Scalar.h"
- #include "llvm/ADT/Statistic.h"
- #include "llvm/Analysis/Dominators.h"
- #include "llvm/IR/Function.h"
- #include "llvm/IR/Instructions.h"
- #include "llvm/Transforms/Utils/PromoteMemToReg.h"
- #include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
- using namespace llvm;
- STATISTIC(NumPromoted, "Number of alloca's promoted");
- namespace {
- struct PromotePass : public FunctionPass {
- static char ID; // Pass identification, replacement for typeid
- PromotePass() : FunctionPass(ID) {
- initializePromotePassPass(*PassRegistry::getPassRegistry());
- }
- // runOnFunction - To run this pass, first we calculate the alloca
- // instructions that are safe for promotion, then we promote each one.
- //
- virtual bool runOnFunction(Function &F);
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequired<DominatorTree>();
- AU.setPreservesCFG();
- // This is a cluster of orthogonal Transforms
- AU.addPreserved<UnifyFunctionExitNodes>();
- AU.addPreservedID(LowerSwitchID);
- AU.addPreservedID(LowerInvokePassID);
- }
- };
- } // end of anonymous namespace
- char PromotePass::ID = 0;
- INITIALIZE_PASS_BEGIN(PromotePass, "mem2reg", "Promote Memory to Register",
- false, false)
- INITIALIZE_PASS_DEPENDENCY(DominatorTree)
- INITIALIZE_PASS_END(PromotePass, "mem2reg", "Promote Memory to Register",
- false, false)
- bool PromotePass::runOnFunction(Function &F) {
- std::vector<AllocaInst*> Allocas;
- BasicBlock &BB = F.getEntryBlock(); // Get the entry node for the function
- bool Changed = false;
- DominatorTree &DT = getAnalysis<DominatorTree>();
- while (1) {
- Allocas.clear();
- // Find allocas that are safe to promote, by looking at all instructions in
- // the entry node
- for (BasicBlock::iterator I = BB.begin(), E = --BB.end(); I != E; ++I)
- if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) // Is it an alloca?
- if (isAllocaPromotable(AI))
- Allocas.push_back(AI);
- if (Allocas.empty()) break;
- PromoteMemToReg(Allocas, DT);
- NumPromoted += Allocas.size();
- Changed = true;
- }
- return Changed;
- }
- // createPromoteMemoryToRegister - Provide an entry point to create this pass.
- //
- FunctionPass *llvm::createPromoteMemoryToRegisterPass() {
- return new PromotePass();
- }