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7f2eff792a
can be used by both the new pass manager and the old. This removes it from any of the virtual mess of the pass interfaces and lets it derive cleanly from the DominatorTreeBase<> template. In turn, tons of boilerplate interface can be nuked and it turns into a very straightforward extension of the base DominatorTree interface. The old analysis pass is now a simple wrapper. The names and style of this split should match the split between CallGraph and CallGraphWrapperPass. All of the users of DominatorTree have been updated to match using many of the same tricks as with CallGraph. The goal is that the common type remains the resulting DominatorTree rather than the pass. This will make subsequent work toward the new pass manager significantly easier. Also in numerous places things became cleaner because I switched from re-running the pass (!!! mid way through some other passes run!!!) to directly recomputing the domtree. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199104 91177308-0d34-0410-b5e6-96231b3b80d8
91 lines
2.9 KiB
C++
91 lines
2.9 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/ADT/Statistic.h"
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/Instructions.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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using namespace llvm;
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STATISTIC(NumPromoted, "Number of alloca's promoted");
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namespace {
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struct 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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initializePromotePassPass(*PassRegistry::getPassRegistry());
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}
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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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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequired<DominatorTreeWrapperPass>();
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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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}
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};
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} // end of anonymous namespace
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char PromotePass::ID = 0;
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INITIALIZE_PASS_BEGIN(PromotePass, "mem2reg", "Promote Memory to Register",
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false, false)
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INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
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INITIALIZE_PASS_END(PromotePass, "mem2reg", "Promote Memory to Register",
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false, false)
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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<DominatorTreeWrapperPass>().getDomTree();
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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);
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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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// 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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