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      1 //===- PostOrderCFGView.cpp - Post order view of CFG blocks ---------------===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 //
      9 // This file implements post order view of the blocks in a CFG.
     10 //
     11 //===----------------------------------------------------------------------===//
     12 
     13 #include "clang/Analysis/Analyses/PostOrderCFGView.h"
     14 #include "clang/Analysis/AnalysisDeclContext.h"
     15 #include "clang/Analysis/CFG.h"
     16 
     17 using namespace clang;
     18 
     19 void PostOrderCFGView::anchor() {}
     20 
     21 PostOrderCFGView::PostOrderCFGView(const CFG *cfg) {
     22   Blocks.reserve(cfg->getNumBlockIDs());
     23   CFGBlockSet BSet(cfg);
     24 
     25   for (po_iterator I = po_iterator::begin(cfg, BSet),
     26                    E = po_iterator::end(cfg, BSet); I != E; ++I) {
     27     BlockOrder[*I] = Blocks.size() + 1;
     28     Blocks.push_back(*I);
     29   }
     30 }
     31 
     32 std::unique_ptr<PostOrderCFGView>
     33 PostOrderCFGView::create(AnalysisDeclContext &ctx) {
     34   const CFG *cfg = ctx.getCFG();
     35   if (!cfg)
     36     return nullptr;
     37   return std::make_unique<PostOrderCFGView>(cfg);
     38 }
     39 
     40 const void *PostOrderCFGView::getTag() { static int x; return &x; }
     41 
     42 bool PostOrderCFGView::BlockOrderCompare::operator()(const CFGBlock *b1,
     43                                                      const CFGBlock *b2) const {
     44   PostOrderCFGView::BlockOrderTy::const_iterator b1It = POV.BlockOrder.find(b1);
     45   PostOrderCFGView::BlockOrderTy::const_iterator b2It = POV.BlockOrder.find(b2);
     46 
     47   unsigned b1V = (b1It == POV.BlockOrder.end()) ? 0 : b1It->second;
     48   unsigned b2V = (b2It == POV.BlockOrder.end()) ? 0 : b2It->second;
     49   return b1V > b2V;
     50 }
     51