1 //==--AnalyzerStatsChecker.cpp - Analyzer visitation statistics --*- C++ -*-==//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 // This file reports various statistics about analyzer visitation.
9 //===----------------------------------------------------------------------===//
10 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
11 #include "clang/AST/DeclObjC.h"
12 #include "clang/Basic/SourceManager.h"
13 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
14 #include "clang/StaticAnalyzer/Core/Checker.h"
15 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
16 #include "clang/StaticAnalyzer/Core/PathSensitive/ExplodedGraph.h"
17 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
18 #include "llvm/ADT/SmallPtrSet.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/ADT/Statistic.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include <optional>
23
24 using namespace clang;
25 using namespace ento;
26
27 #define DEBUG_TYPE "StatsChecker"
28
29 STATISTIC(NumBlocks,
30 "The # of blocks in top level functions");
31 STATISTIC(NumBlocksUnreachable,
32 "The # of unreachable blocks in analyzing top level functions");
33
34 namespace {
35 class AnalyzerStatsChecker : public Checker<check::EndAnalysis> {
36 public:
37 void checkEndAnalysis(ExplodedGraph &G, BugReporter &B,ExprEngine &Eng) const;
38 };
39 }
40
checkEndAnalysis(ExplodedGraph & G,BugReporter & B,ExprEngine & Eng) const41 void AnalyzerStatsChecker::checkEndAnalysis(ExplodedGraph &G,
42 BugReporter &B,
43 ExprEngine &Eng) const {
44 const CFG *C = nullptr;
45 const SourceManager &SM = B.getSourceManager();
46 llvm::SmallPtrSet<const CFGBlock*, 32> reachable;
47
48 // Root node should have the location context of the top most function.
49 const ExplodedNode *GraphRoot = *G.roots_begin();
50 const LocationContext *LC = GraphRoot->getLocation().getLocationContext();
51
52 const Decl *D = LC->getDecl();
53
54 // Iterate over the exploded graph.
55 for (ExplodedGraph::node_iterator I = G.nodes_begin();
56 I != G.nodes_end(); ++I) {
57 const ProgramPoint &P = I->getLocation();
58
59 // Only check the coverage in the top level function (optimization).
60 if (D != P.getLocationContext()->getDecl())
61 continue;
62
63 if (std::optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) {
64 const CFGBlock *CB = BE->getBlock();
65 reachable.insert(CB);
66 }
67 }
68
69 // Get the CFG and the Decl of this block.
70 C = LC->getCFG();
71
72 unsigned total = 0, unreachable = 0;
73
74 // Find CFGBlocks that were not covered by any node
75 for (CFG::const_iterator I = C->begin(); I != C->end(); ++I) {
76 const CFGBlock *CB = *I;
77 ++total;
78 // Check if the block is unreachable
79 if (!reachable.count(CB)) {
80 ++unreachable;
81 }
82 }
83
84 // We never 'reach' the entry block, so correct the unreachable count
85 unreachable--;
86 // There is no BlockEntrance corresponding to the exit block as well, so
87 // assume it is reached as well.
88 unreachable--;
89
90 // Generate the warning string
91 SmallString<128> buf;
92 llvm::raw_svector_ostream output(buf);
93 PresumedLoc Loc = SM.getPresumedLoc(D->getLocation());
94 if (!Loc.isValid())
95 return;
96
97 if (isa<FunctionDecl, ObjCMethodDecl>(D)) {
98 const NamedDecl *ND = cast<NamedDecl>(D);
99 output << *ND;
100 } else if (isa<BlockDecl>(D)) {
101 output << "block(line:" << Loc.getLine() << ":col:" << Loc.getColumn();
102 }
103
104 NumBlocksUnreachable += unreachable;
105 NumBlocks += total;
106 std::string NameOfRootFunction = std::string(output.str());
107
108 output << " -> Total CFGBlocks: " << total << " | Unreachable CFGBlocks: "
109 << unreachable << " | Exhausted Block: "
110 << (Eng.wasBlocksExhausted() ? "yes" : "no")
111 << " | Empty WorkList: "
112 << (Eng.hasEmptyWorkList() ? "yes" : "no");
113
114 B.EmitBasicReport(D, this, "Analyzer Statistics", "Internal Statistics",
115 output.str(), PathDiagnosticLocation(D, SM));
116
117 // Emit warning for each block we bailed out on.
118 typedef CoreEngine::BlocksExhausted::const_iterator ExhaustedIterator;
119 const CoreEngine &CE = Eng.getCoreEngine();
120 for (ExhaustedIterator I = CE.blocks_exhausted_begin(),
121 E = CE.blocks_exhausted_end(); I != E; ++I) {
122 const BlockEdge &BE = I->first;
123 const CFGBlock *Exit = BE.getDst();
124 if (Exit->empty())
125 continue;
126 const CFGElement &CE = Exit->front();
127 if (std::optional<CFGStmt> CS = CE.getAs<CFGStmt>()) {
128 SmallString<128> bufI;
129 llvm::raw_svector_ostream outputI(bufI);
130 outputI << "(" << NameOfRootFunction << ")" <<
131 ": The analyzer generated a sink at this point";
132 B.EmitBasicReport(
133 D, this, "Sink Point", "Internal Statistics", outputI.str(),
134 PathDiagnosticLocation::createBegin(CS->getStmt(), SM, LC));
135 }
136 }
137 }
138
registerAnalyzerStatsChecker(CheckerManager & mgr)139 void ento::registerAnalyzerStatsChecker(CheckerManager &mgr) {
140 mgr.registerChecker<AnalyzerStatsChecker>();
141 }
142
shouldRegisterAnalyzerStatsChecker(const CheckerManager & mgr)143 bool ento::shouldRegisterAnalyzerStatsChecker(const CheckerManager &mgr) {
144 return true;
145 }
146