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Currently this pass will delete the variable declaration info, and keep the line number info. But the kept line number info is not updated, and some is redundant or not correct, this patch just updates those info. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65123 91177308-0d34-0410-b5e6-96231b3b80d8
119 lines
3.7 KiB
C++
119 lines
3.7 KiB
C++
//===- Mem2Reg.cpp - The -mem2reg pass, a wrapper around the Utils lib ----===//
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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 pass is a simple pass wrapper around the PromoteMemToReg function call
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// exposed by the Utils library.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "mem2reg"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Transforms/Utils/PromoteMemToReg.h"
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#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
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#include "llvm/IntrinsicInst.h"
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Instructions.h"
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#include "llvm/Function.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Support/Compiler.h"
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using namespace llvm;
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STATISTIC(NumPromoted, "Number of alloca's promoted");
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namespace {
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struct VISIBILITY_HIDDEN PromotePass : public FunctionPass {
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static char ID; // Pass identification, replacement for typeid
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PromotePass() : FunctionPass(&ID) {}
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// runOnFunction - To run this pass, first we calculate the alloca
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// instructions that are safe for promotion, then we promote each one.
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//
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virtual bool runOnFunction(Function &F);
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// getAnalysisUsage - We need dominance frontiers
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//
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequired<DominatorTree>();
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AU.addRequired<DominanceFrontier>();
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AU.setPreservesCFG();
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// This is a cluster of orthogonal Transforms
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AU.addPreserved<UnifyFunctionExitNodes>();
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AU.addPreservedID(LowerSwitchID);
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AU.addPreservedID(LowerInvokePassID);
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AU.addPreservedID(LowerAllocationsID);
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}
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};
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} // end of anonymous namespace
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char PromotePass::ID = 0;
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static RegisterPass<PromotePass> X("mem2reg", "Promote Memory to Register");
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/// Remove the invalid or redundant debug information.
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static void CleanDbgInfo(Function& F) {
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std::vector<Instruction*> DeadDbgs;
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for (Function::iterator BBI = F.begin(), BBE = F.end(); BBI != BBE; ++BBI) {
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if (BBI->size() <= 1)
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continue;
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for (BasicBlock::iterator I = BBI->begin(), E = BBI->getTerminator();
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I != E; ++I) {
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BasicBlock::iterator NextI = I;
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++NextI;
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if (isa<DbgStopPointInst>(I) && isa<DbgStopPointInst>(NextI))
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DeadDbgs.push_back(I);
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else if (isa<DbgStopPointInst>(I) && isa<BranchInst>(NextI))
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DeadDbgs.push_back(I);
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}
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}
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while (!DeadDbgs.empty()) {
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Instruction *Inst = DeadDbgs.back();
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DeadDbgs.pop_back();
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Inst->eraseFromParent();
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}
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}
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bool PromotePass::runOnFunction(Function &F) {
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std::vector<AllocaInst*> Allocas;
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BasicBlock &BB = F.getEntryBlock(); // Get the entry node for the function
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bool Changed = false;
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DominatorTree &DT = getAnalysis<DominatorTree>();
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DominanceFrontier &DF = getAnalysis<DominanceFrontier>();
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while (1) {
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Allocas.clear();
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// Find allocas that are safe to promote, by looking at all instructions in
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// the entry node
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for (BasicBlock::iterator I = BB.begin(), E = --BB.end(); I != E; ++I)
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if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) // Is it an alloca?
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if (isAllocaPromotable(AI))
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Allocas.push_back(AI);
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if (Allocas.empty()) break;
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PromoteMemToReg(Allocas, DT, DF);
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CleanDbgInfo(F);
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NumPromoted += Allocas.size();
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Changed = true;
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}
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return Changed;
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}
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// Publically exposed interface to pass...
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const PassInfo *const llvm::PromoteMemoryToRegisterID = &X;
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// createPromoteMemoryToRegister - Provide an entry point to create this pass.
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//
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FunctionPass *llvm::createPromoteMemoryToRegisterPass() {
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return new PromotePass();
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}
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