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/AST/DeclObjC.h"
20 #include "clang/Basic/SourceManager.h"
21 #include "llvm/ADT/SmallPtrSet.h"
22 
23 using namespace clang;
24 using namespace ento;
25 
26 namespace {
27 class AnalyzerStatsChecker : public Checker<check::EndAnalysis> {
28 public:
29   void checkEndAnalysis(ExplodedGraph &G, BugReporter &B,ExprEngine &Eng) const;
30 };
31 }
32 
33 void AnalyzerStatsChecker::checkEndAnalysis(ExplodedGraph &G,
34                                             BugReporter &B,
35                                             ExprEngine &Eng) const {
36   const CFG *C  = 0;
37   const Decl *D = 0;
38   const LocationContext *LC = 0;
39   const SourceManager &SM = B.getSourceManager();
40   llvm::SmallPtrSet<const CFGBlock*, 256> reachable;
41 
42   // Iterate over explodedgraph
43   for (ExplodedGraph::node_iterator I = G.nodes_begin();
44       I != G.nodes_end(); ++I) {
45     const ProgramPoint &P = I->getLocation();
46     // Save the LocationContext if we don't have it already
47     if (!LC)
48       LC = P.getLocationContext();
49 
50     if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&P)) {
51       const CFGBlock *CB = BE->getBlock();
52       reachable.insert(CB);
53     }
54   }
55 
56   // Get the CFG and the Decl of this block
57   C = LC->getCFG();
58   D = LC->getAnalysisDeclContext()->getDecl();
59 
60   unsigned total = 0, unreachable = 0;
61 
62   // Find CFGBlocks that were not covered by any node
63   for (CFG::const_iterator I = C->begin(); I != C->end(); ++I) {
64     const CFGBlock *CB = *I;
65     ++total;
66     // Check if the block is unreachable
67     if (!reachable.count(CB)) {
68       ++unreachable;
69     }
70   }
71 
72   // We never 'reach' the entry block, so correct the unreachable count
73   unreachable--;
74 
75   // Generate the warning string
76   llvm::SmallString<128> buf;
77   llvm::raw_svector_ostream output(buf);
78   PresumedLoc Loc = SM.getPresumedLoc(D->getLocation());
79   if (Loc.isValid()) {
80     output << Loc.getFilename() << " : ";
81 
82     if (isa<FunctionDecl>(D) || isa<ObjCMethodDecl>(D)) {
83       const NamedDecl *ND = cast<NamedDecl>(D);
84       output << *ND;
85     }
86     else if (isa<BlockDecl>(D)) {
87       output << "block(line:" << Loc.getLine() << ":col:" << Loc.getColumn();
88     }
89   }
90 
91   output << " -> Total CFGBlocks: " << total << " | Unreachable CFGBlocks: "
92       << unreachable << " | Exhausted Block: "
93       << (Eng.wasBlocksExhausted() ? "yes" : "no")
94       << " | Empty WorkList: "
95       << (Eng.hasEmptyWorkList() ? "yes" : "no");
96 
97   B.EmitBasicReport("Analyzer Statistics", "Internal Statistics", output.str(),
98       PathDiagnosticLocation(D, SM));
99 
100   // Emit warning for each block we bailed out on
101   typedef CoreEngine::BlocksExhausted::const_iterator ExhaustedIterator;
102   const CoreEngine &CE = Eng.getCoreEngine();
103   for (ExhaustedIterator I = CE.blocks_exhausted_begin(),
104       E = CE.blocks_exhausted_end(); I != E; ++I) {
105     const BlockEdge &BE =  I->first;
106     const CFGBlock *Exit = BE.getDst();
107     const CFGElement &CE = Exit->front();
108     if (const CFGStmt *CS = dyn_cast<CFGStmt>(&CE))
109       B.EmitBasicReport("Bailout Point", "Internal Statistics", "The analyzer "
110           "stopped analyzing at this point",
111           PathDiagnosticLocation::createBegin(CS->getStmt(), SM, LC));
112   }
113 }
114 
115 void ento::registerAnalyzerStatsChecker(CheckerManager &mgr) {
116   mgr.registerChecker<AnalyzerStatsChecker>();
117 }
118