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must be called in the pass's constructor. This function uses static dependency declarations to recursively initialize the pass's dependencies. Clients that only create passes through the createFooPass() APIs will require no changes. Clients that want to use the CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h before parsing commandline arguments. I have tested this with all standard configurations of clang and llvm-gcc on Darwin. It is possible that there are problems with the static dependencies that will only be visible with non-standard options. If you encounter any crash in pass registration/creation, please send the testcase to me directly. llvm-svn: 116820
99 lines
3.2 KiB
C++
99 lines
3.2 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/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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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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// 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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}
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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(DominatorTree)
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INITIALIZE_PASS_DEPENDENCY(DominanceFrontier)
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INITIALIZE_PASS_DEPENDENCY(UnifyFunctionExitNodes)
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INITIALIZE_PASS_DEPENDENCY(LowerSwitch)
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INITIALIZE_PASS_DEPENDENCY(LowerInvoke)
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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<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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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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