| //===- Mem2Reg.cpp - The -mem2reg pass, a wrapper around the Utils lib ----===// |
| // |
| // 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 pass is a simple pass wrapper around the PromoteMemToReg function call |
| // exposed by the Utils library. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Transforms/Scalar.h" |
| #include "llvm/Transforms/Utils/PromoteMemToReg.h" |
| #include "llvm/Analysis/Dominators.h" |
| #include "llvm/iMemory.h" |
| #include "llvm/Function.h" |
| #include "llvm/Target/TargetData.h" |
| #include "Support/Statistic.h" |
| |
| namespace { |
| Statistic<> NumPromoted("mem2reg", "Number of alloca's promoted"); |
| |
| struct PromotePass : public FunctionPass { |
| // 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); |
| |
| // getAnalysisUsage - We need dominance frontiers |
| // |
| virtual void getAnalysisUsage(AnalysisUsage &AU) const { |
| AU.addRequired<DominatorTree>(); |
| AU.addRequired<DominanceFrontier>(); |
| AU.addRequired<TargetData>(); |
| AU.setPreservesCFG(); |
| } |
| }; |
| |
| RegisterOpt<PromotePass> X("mem2reg", "Promote Memory to Register"); |
| } // end of anonymous namespace |
| |
| bool PromotePass::runOnFunction(Function &F) { |
| std::vector<AllocaInst*> Allocas; |
| const TargetData &TD = getAnalysis<TargetData>(); |
| |
| BasicBlock &BB = F.getEntryBlock(); // Get the entry node for the function |
| |
| bool Changed = false; |
| |
| DominatorTree &DT = getAnalysis<DominatorTree>(); |
| DominanceFrontier &DF = getAnalysis<DominanceFrontier>(); |
| |
| 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, TD)) |
| Allocas.push_back(AI); |
| |
| if (Allocas.empty()) break; |
| |
| PromoteMemToReg(Allocas, DT, DF, TD); |
| NumPromoted += Allocas.size(); |
| Changed = true; |
| } |
| |
| return Changed; |
| } |
| |
| // createPromoteMemoryToRegister - Provide an entry point to create this pass. |
| // |
| Pass *createPromoteMemoryToRegister() { |
| return new PromotePass(); |
| } |