clang/lib/Analysis/PostOrderCFGView.cpp

   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 }