1 //===--- CFGStmtMap.h - Map from Stmt* to CFGBlock* -----------*- 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 defines the CFGStmtMap class, which defines a mapping from
11 // Stmt* to CFGBlock*
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "llvm/ADT/DenseMap.h"
16 #include "clang/AST/ParentMap.h"
17 #include "clang/Analysis/CFG.h"
18 #include "clang/Analysis/CFGStmtMap.h"
19
20 using namespace clang;
21
22 typedef llvm::DenseMap<const Stmt*, CFGBlock*> SMap;
AsMap(void * m)23 static SMap *AsMap(void *m) { return (SMap*) m; }
24
~CFGStmtMap()25 CFGStmtMap::~CFGStmtMap() { delete AsMap(M); }
26
getBlock(Stmt * S)27 CFGBlock *CFGStmtMap::getBlock(Stmt *S) {
28 SMap *SM = AsMap(M);
29 Stmt *X = S;
30
31 // If 'S' isn't in the map, walk the ParentMap to see if one of its ancestors
32 // is in the map.
33 while (X) {
34 SMap::iterator I = SM->find(X);
35 if (I != SM->end()) {
36 CFGBlock *B = I->second;
37 // Memoize this lookup.
38 if (X != S)
39 (*SM)[X] = B;
40 return B;
41 }
42
43 X = PM->getParentIgnoreParens(X);
44 }
45
46 return nullptr;
47 }
48
Accumulate(SMap & SM,CFGBlock * B)49 static void Accumulate(SMap &SM, CFGBlock *B) {
50 // First walk the block-level expressions.
51 for (CFGBlock::iterator I = B->begin(), E = B->end(); I != E; ++I) {
52 const CFGElement &CE = *I;
53 Optional<CFGStmt> CS = CE.getAs<CFGStmt>();
54 if (!CS)
55 continue;
56
57 CFGBlock *&Entry = SM[CS->getStmt()];
58 // If 'Entry' is already initialized (e.g., a terminator was already),
59 // skip.
60 if (Entry)
61 continue;
62
63 Entry = B;
64
65 }
66
67 // Look at the label of the block.
68 if (Stmt *Label = B->getLabel())
69 SM[Label] = B;
70
71 // Finally, look at the terminator. If the terminator was already added
72 // because it is a block-level expression in another block, overwrite
73 // that mapping.
74 if (Stmt *Term = B->getTerminator())
75 SM[Term] = B;
76 }
77
Build(CFG * C,ParentMap * PM)78 CFGStmtMap *CFGStmtMap::Build(CFG *C, ParentMap *PM) {
79 if (!C || !PM)
80 return nullptr;
81
82 SMap *SM = new SMap();
83
84 // Walk all blocks, accumulating the block-level expressions, labels,
85 // and terminators.
86 for (CFG::iterator I = C->begin(), E = C->end(); I != E; ++I)
87 Accumulate(*SM, *I);
88
89 return new CFGStmtMap(PM, SM);
90 }
91
92