a208a73390
to recover the performance after r214064. Also sorts out the naming for PostOrderCFGView, ReversePostOrderCFGView, BackwardDataflowWorklist and ForwardDataflowWorklist, to match the accepted terminology. Also unifies BackwardDataflowWorklist and ForwardDataflowWorklist to share the "worklist for prioritization, post-order traversal for fallback" logic, and to avoid repetitive sorting. Also cleans up comments in the affected area. llvm-svn: 215650
98 lines
3.2 KiB
C++
98 lines
3.2 KiB
C++
//===- PostOrderCFGView.cpp - Post order view of CFG blocks -------*- C++ --*-//
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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 file implements post order views of the blocks in a CFG.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Analysis/Analyses/PostOrderCFGView.h"
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using namespace clang;
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void PostOrderCFGView::anchor() { }
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ReversePostOrderCFGView::ReversePostOrderCFGView(const CFG *cfg) {
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Blocks.reserve(cfg->getNumBlockIDs());
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CFGBlockSet BSet(cfg);
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typedef llvm::po_iterator<const CFG*, CFGBlockSet, true> po_iterator;
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for (po_iterator I = po_iterator::begin(cfg, BSet),
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E = po_iterator::end(cfg, BSet); I != E; ++I) {
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Blocks.push_back(*I);
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BlockOrder[*I] = Blocks.size();
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}
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}
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PostOrderCFGView *PostOrderCFGView::create(AnalysisDeclContext &ctx) {
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const CFG *cfg = ctx.getCFG();
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if (!cfg)
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return nullptr;
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return new PostOrderCFGView(cfg);
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}
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const void *PostOrderCFGView::getTag() { static int x; return &x; }
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bool PostOrderCFGView::BlockOrderCompare::operator()(const CFGBlock *b1,
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const CFGBlock *b2) const {
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PostOrderCFGView::BlockOrderTy::const_iterator b1It = POV.BlockOrder.find(b1);
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PostOrderCFGView::BlockOrderTy::const_iterator b2It = POV.BlockOrder.find(b2);
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unsigned b1V = (b1It == POV.BlockOrder.end()) ? 0 : b1It->second;
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unsigned b2V = (b2It == POV.BlockOrder.end()) ? 0 : b2It->second;
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return b1V > b2V;
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}
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PostOrderCFGView::PostOrderCFGView(const CFG *cfg) {
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unsigned size = cfg->getNumBlockIDs();
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Blocks.reserve(size);
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CFGBlockSet BSet(cfg);
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typedef llvm::po_iterator<const CFG*, CFGBlockSet, true,
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llvm::GraphTraits<llvm::Inverse<const CFG*> >
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> po_iterator;
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for (po_iterator I = po_iterator::begin(cfg, BSet),
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E = po_iterator::end(cfg, BSet); I != E; ++I) {
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Blocks.push_back(*I);
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BlockOrder[*I] = Blocks.size();
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}
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// It may be that some blocks are inaccessible going from the CFG exit upwards
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// (e.g. infinite loops); we still need to add them.
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for (CFG::const_iterator I = cfg->begin(), E = cfg->end();
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(Blocks.size() < size) && (I != E); ++I) {
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const CFGBlock* block = *I;
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// Add a chain going upwards.
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while (!BlockOrder.count(block)) {
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Blocks.push_back(block);
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BlockOrder[block] = Blocks.size();
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CFGBlock::const_pred_iterator PI = block->pred_begin(),
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PE = block->pred_end();
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for (; PI != PE; ++PI) {
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const CFGBlock* pred = *PI;
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if (pred && !BlockOrder.count(pred)) {
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block = pred;
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break;
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}
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}
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// Chain ends when we couldn't find an unmapped pred.
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if (PI == PE) break;
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}
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}
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}
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ReversePostOrderCFGView *
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ReversePostOrderCFGView::create(AnalysisDeclContext &ctx) {
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const CFG *cfg = ctx.getCFG();
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if (!cfg)
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return nullptr;
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return new ReversePostOrderCFGView(cfg);
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}
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