clang  9.0.0
AnalyzerStatsChecker.cpp
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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 //===----------------------------------------------------------------------===//
11 #include "clang/AST/DeclObjC.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 
23 using namespace clang;
24 using namespace ento;
25 
26 #define DEBUG_TYPE "StatsChecker"
27 
28 STATISTIC(NumBlocks,
29  "The # of blocks in top level functions");
30 STATISTIC(NumBlocksUnreachable,
31  "The # of unreachable blocks in analyzing top level functions");
32 
33 namespace {
34 class AnalyzerStatsChecker : public Checker<check::EndAnalysis> {
35 public:
36  void checkEndAnalysis(ExplodedGraph &G, BugReporter &B,ExprEngine &Eng) const;
37 };
38 }
39 
40 void AnalyzerStatsChecker::checkEndAnalysis(ExplodedGraph &G,
41  BugReporter &B,
42  ExprEngine &Eng) const {
43  const CFG *C = nullptr;
44  const SourceManager &SM = B.getSourceManager();
45  llvm::SmallPtrSet<const CFGBlock*, 32> reachable;
46 
47  // Root node should have the location context of the top most function.
48  const ExplodedNode *GraphRoot = *G.roots_begin();
49  const LocationContext *LC = GraphRoot->getLocation().getLocationContext();
50 
51  const Decl *D = LC->getDecl();
52 
53  // Iterate over the exploded graph.
54  for (ExplodedGraph::node_iterator I = G.nodes_begin();
55  I != G.nodes_end(); ++I) {
56  const ProgramPoint &P = I->getLocation();
57 
58  // Only check the coverage in the top level function (optimization).
59  if (D != P.getLocationContext()->getDecl())
60  continue;
61 
63  const CFGBlock *CB = BE->getBlock();
64  reachable.insert(CB);
65  }
66  }
67 
68  // Get the CFG and the Decl of this block.
69  C = LC->getCFG();
70 
71  unsigned total = 0, unreachable = 0;
72 
73  // Find CFGBlocks that were not covered by any node
74  for (CFG::const_iterator I = C->begin(); I != C->end(); ++I) {
75  const CFGBlock *CB = *I;
76  ++total;
77  // Check if the block is unreachable
78  if (!reachable.count(CB)) {
79  ++unreachable;
80  }
81  }
82 
83  // We never 'reach' the entry block, so correct the unreachable count
84  unreachable--;
85  // There is no BlockEntrance corresponding to the exit block as well, so
86  // assume it is reached as well.
87  unreachable--;
88 
89  // Generate the warning string
90  SmallString<128> buf;
91  llvm::raw_svector_ostream output(buf);
92  PresumedLoc Loc = SM.getPresumedLoc(D->getLocation());
93  if (!Loc.isValid())
94  return;
95 
96  if (isa<FunctionDecl>(D) || isa<ObjCMethodDecl>(D)) {
97  const NamedDecl *ND = cast<NamedDecl>(D);
98  output << *ND;
99  }
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 = 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 (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 
139 void ento::registerAnalyzerStatsChecker(CheckerManager &mgr) {
140  mgr.registerChecker<AnalyzerStatsChecker>();
141 }
142 
143 bool ento::shouldRegisterAnalyzerStatsChecker(const LangOptions &LO) {
144  return true;
145 }
bool empty() const
Definition: CFG.h:732
CFGElement front() const
Definition: CFG.h:718
Defines the SourceManager interface.
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:88
StringRef P
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:49
iterator end()
Definition: CFG.h:1112
STATISTIC(NumBlocks, "The # of blocks in top level functions")
CFGBlockListTy::const_iterator const_iterator
Definition: CFG.h:1104
Represents a single basic block in a source-level CFG.
Definition: CFG.h:570
bool isValid() const
AllNodesTy::iterator node_iterator
Represents a source-level, intra-procedural CFG that represents the control-flow of a Stmt...
Definition: CFG.h:1035
unsigned getLine() const
Return the presumed line number of this location.
const CFGBlock * getDst() const
Definition: ProgramPoint.h:515
Represents an unpacked "presumed" location which can be presented to the user.
const SourceManager & SM
Definition: Format.cpp:1572
static PathDiagnosticLocation createBegin(const Decl *D, const SourceManager &SM)
Create a location for the beginning of the declaration.
unsigned getColumn() const
Return the presumed column number of this location.
iterator begin()
Definition: CFG.h:1111
Optional< T > getAs() const
Convert to the specified CFGElement type, returning None if this CFGElement is not of the desired typ...
Definition: CFG.h:109
Dataflow Directional Tag Classes.
PresumedLoc getPresumedLoc(SourceLocation Loc, bool UseLineDirectives=true) const
Returns the "presumed" location of a SourceLocation specifies.
const Decl * getDecl() const
const LocationContext * getLocationContext() const
Definition: ProgramPoint.h:179
Represents a top-level expression in a basic block.
Definition: CFG.h:55
This represents a decl that may have a name.
Definition: Decl.h:248
Optional< T > getAs() const
Convert to the specified ProgramPoint type, returning None if this ProgramPoint is not of the desired...
Definition: ProgramPoint.h:151
This class handles loading and caching of source files into memory.
SourceLocation getLocation() const
Definition: DeclBase.h:429