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1 //==--AnalyzerStatsChecker.cpp - Analyzer visitation statistics --*- 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 // This file reports various statistics about analyzer visitation.
10 //===----------------------------------------------------------------------===//
11 
12 #include "ClangSACheckers.h"
13 #include "clang/StaticAnalyzer/Core/Checker.h"
14 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
15 #include "clang/StaticAnalyzer/Core/PathSensitive/ExplodedGraph.h"
16 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
17 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
18 
19 #include "clang/Basic/SourceManager.h"
20 #include "llvm/ADT/SmallPtrSet.h"
21 
22 using namespace clang;
23 using namespace ento;
24 
25 namespace {
26 class AnalyzerStatsChecker : public Checker<check::EndAnalysis> {
27 public:
28   void checkEndAnalysis(ExplodedGraph &G, BugReporter &B,ExprEngine &Eng) const;
29 };
30 }
31 
checkEndAnalysis(ExplodedGraph & G,BugReporter & B,ExprEngine & Eng) const32 void AnalyzerStatsChecker::checkEndAnalysis(ExplodedGraph &G,
33                                             BugReporter &B,
34                                             ExprEngine &Eng) const {
35   const CFG *C  = 0;
36   const Decl *D = 0;
37   const LocationContext *LC = 0;
38   const SourceManager &SM = B.getSourceManager();
39   llvm::SmallPtrSet<const CFGBlock*, 256> reachable;
40 
41   // Iterate over explodedgraph
42   for (ExplodedGraph::node_iterator I = G.nodes_begin();
43       I != G.nodes_end(); ++I) {
44     const ProgramPoint &P = I->getLocation();
45     // Save the LocationContext if we don't have it already
46     if (!LC)
47       LC = P.getLocationContext();
48 
49     if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&P)) {
50       const CFGBlock *CB = BE->getBlock();
51       reachable.insert(CB);
52     }
53   }
54 
55   // Get the CFG and the Decl of this block
56   C = LC->getCFG();
57   D = LC->getAnalysisContext()->getDecl();
58 
59   unsigned total = 0, unreachable = 0;
60 
61   // Find CFGBlocks that were not covered by any node
62   for (CFG::const_iterator I = C->begin(); I != C->end(); ++I) {
63     const CFGBlock *CB = *I;
64     ++total;
65     // Check if the block is unreachable
66     if (!reachable.count(CB)) {
67       ++unreachable;
68     }
69   }
70 
71   // We never 'reach' the entry block, so correct the unreachable count
72   unreachable--;
73 
74   // Generate the warning string
75   llvm::SmallString<128> buf;
76   llvm::raw_svector_ostream output(buf);
77   PresumedLoc Loc = SM.getPresumedLoc(D->getLocation());
78   if (Loc.isValid()) {
79     output << Loc.getFilename() << " : ";
80 
81     if (isa<FunctionDecl>(D) || isa<ObjCMethodDecl>(D)) {
82       const NamedDecl *ND = cast<NamedDecl>(D);
83       output << ND;
84     }
85     else if (isa<BlockDecl>(D)) {
86       output << "block(line:" << Loc.getLine() << ":col:" << Loc.getColumn();
87     }
88   }
89 
90   output << " -> Total CFGBlocks: " << total << " | Unreachable CFGBlocks: "
91       << unreachable << " | Exhausted Block: "
92       << (Eng.wasBlocksExhausted() ? "yes" : "no")
93       << " | Empty WorkList: "
94       << (Eng.hasEmptyWorkList() ? "yes" : "no");
95 
96   B.EmitBasicReport("Analyzer Statistics", "Internal Statistics", output.str(),
97       D->getLocation());
98 
99   // Emit warning for each block we bailed out on
100   typedef CoreEngine::BlocksExhausted::const_iterator ExhaustedIterator;
101   const CoreEngine &CE = Eng.getCoreEngine();
102   for (ExhaustedIterator I = CE.blocks_exhausted_begin(),
103       E = CE.blocks_exhausted_end(); I != E; ++I) {
104     const BlockEdge &BE =  I->first;
105     const CFGBlock *Exit = BE.getDst();
106     const CFGElement &CE = Exit->front();
107     if (const CFGStmt *CS = dyn_cast<CFGStmt>(&CE))
108       B.EmitBasicReport("Bailout Point", "Internal Statistics", "The analyzer "
109           "stopped analyzing at this point", CS->getStmt()->getLocStart());
110   }
111 }
112 
registerAnalyzerStatsChecker(CheckerManager & mgr)113 void ento::registerAnalyzerStatsChecker(CheckerManager &mgr) {
114   mgr.registerChecker<AnalyzerStatsChecker>();
115 }
116