1 //===- PostOrderCFGView.cpp - Post order view of CFG blocks ---------------===//
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 #include "clang/Analysis/AnalysisDeclContext.h"
16 #include "clang/Analysis/CFG.h"
17 
18 using namespace clang;
19 
anchor()20 void PostOrderCFGView::anchor() {}
21 
PostOrderCFGView(const CFG * cfg)22 PostOrderCFGView::PostOrderCFGView(const CFG *cfg) {
23   Blocks.reserve(cfg->getNumBlockIDs());
24   CFGBlockSet BSet(cfg);
25 
26   for (po_iterator I = po_iterator::begin(cfg, BSet),
27                    E = po_iterator::end(cfg, BSet); I != E; ++I) {
28     BlockOrder[*I] = Blocks.size() + 1;
29     Blocks.push_back(*I);
30   }
31 }
32 
create(AnalysisDeclContext & ctx)33 PostOrderCFGView *PostOrderCFGView::create(AnalysisDeclContext &ctx) {
34   const CFG *cfg = ctx.getCFG();
35   if (!cfg)
36     return nullptr;
37   return new PostOrderCFGView(cfg);
38 }
39 
getTag()40 const void *PostOrderCFGView::getTag() { static int x; return &x; }
41 
operator ()(const CFGBlock * b1,const CFGBlock * b2) const42 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