1 //===- PostOrderCFGView.cpp - Post order view of CFG blocks -------*- C++ --*-//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements post order view of the blocks in a CFG.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Analysis/Analyses/PostOrderCFGView.h"
15 
16 using namespace clang;
17 
18 PostOrderCFGView::PostOrderCFGView(const CFG *cfg) {
19   Blocks.reserve(cfg->getNumBlockIDs());
20   CFGBlockSet BSet(cfg);
21 
22   for (po_iterator I = po_iterator::begin(cfg, BSet),
23                    E = po_iterator::end(cfg, BSet); I != E; ++I) {
24     BlockOrder[*I] = Blocks.size() + 1;
25     Blocks.push_back(*I);
26   }
27 }
28 
29 PostOrderCFGView *PostOrderCFGView::create(AnalysisDeclContext &ctx) {
30   const CFG *cfg = ctx.getCFG();
31   if (!cfg)
32     return 0;
33   return new PostOrderCFGView(cfg);
34 }
35 
36 const void *PostOrderCFGView::getTag() { static int x; return &x; }
37 
38 bool PostOrderCFGView::BlockOrderCompare::operator()(const CFGBlock *b1,
39                                                      const CFGBlock *b2) const {
40   PostOrderCFGView::BlockOrderTy::const_iterator b1It = POV.BlockOrder.find(b1);
41   PostOrderCFGView::BlockOrderTy::const_iterator b2It = POV.BlockOrder.find(b2);
42 
43   unsigned b1V = (b1It == POV.BlockOrder.end()) ? 0 : b1It->second;
44   unsigned b2V = (b2It == POV.BlockOrder.end()) ? 0 : b2It->second;
45   return b1V > b2V;
46 }
47 
48