xref: /freebsd/contrib/llvm-project/clang/lib/Analysis/PostOrderCFGView.cpp (revision 2f513db72b034fd5ef7f080b11be5c711c15186a)
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 PostOrderCFGView *PostOrderCFGView::create(AnalysisDeclContext &ctx) {
33   const CFG *cfg = ctx.getCFG();
34   if (!cfg)
35     return nullptr;
36   return new PostOrderCFGView(cfg);
37 }
38 
39 const void *PostOrderCFGView::getTag() { static int x; return &x; }
40 
41 bool 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