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
17using namespace clang;
18
19void PostOrderCFGView::anchor() {}
20
21PostOrderCFGView::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
32PostOrderCFGView *PostOrderCFGView::create(AnalysisDeclContext &ctx) {
33  const CFG *cfg = ctx.getCFG();
34  if (!cfg)
35    return nullptr;
36  return new PostOrderCFGView(cfg);
37}
38
39const void *PostOrderCFGView::getTag() { static int x; return &x; }
40
41bool PostOrderCFGView::BlockOrderCompare::operator()(const CFGBlock *b1,
42                                                     const CFGBlock *b2) const {
43  PostOrderCFGView::BlockOrderTy::const_iterator b1It = POV.BlockOrder.find(b1);
44  PostOrderCFGView::BlockOrderTy::const_iterator b2It = POV.BlockOrder.find(b2);
45
46  unsigned b1V = (b1It == POV.BlockOrder.end()) ? 0 : b1It->second;
47  unsigned b2V = (b2It == POV.BlockOrder.end()) ? 0 : b2It->second;
48  return b1V > b2V;
49}
50