clang-tools  4.0.0
AssertSideEffectCheck.cpp
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1 //===--- AssertSideEffectCheck.cpp - clang-tidy ---------------------------===//
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 #include "AssertSideEffectCheck.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/Frontend/CompilerInstance.h"
14 #include "clang/Lex/Lexer.h"
15 #include "llvm/ADT/SmallVector.h"
16 #include "llvm/ADT/StringRef.h"
17 #include "llvm/Support/Casting.h"
18 #include <algorithm>
19 #include <string>
20 
21 using namespace clang::ast_matchers;
22 
23 namespace clang {
24 namespace tidy {
25 namespace misc {
26 
27 namespace {
28 
29 AST_MATCHER_P(Expr, hasSideEffect, bool, CheckFunctionCalls) {
30  const Expr *E = &Node;
31 
32  if (const auto *Op = dyn_cast<UnaryOperator>(E)) {
33  UnaryOperator::Opcode OC = Op->getOpcode();
34  return OC == UO_PostInc || OC == UO_PostDec || OC == UO_PreInc ||
35  OC == UO_PreDec;
36  }
37 
38  if (const auto *Op = dyn_cast<BinaryOperator>(E)) {
39  return Op->isAssignmentOp();
40  }
41 
42  if (const auto *OpCallExpr = dyn_cast<CXXOperatorCallExpr>(E)) {
43  OverloadedOperatorKind OpKind = OpCallExpr->getOperator();
44  return OpKind == OO_Equal || OpKind == OO_PlusEqual ||
45  OpKind == OO_MinusEqual || OpKind == OO_StarEqual ||
46  OpKind == OO_SlashEqual || OpKind == OO_AmpEqual ||
47  OpKind == OO_PipeEqual || OpKind == OO_CaretEqual ||
48  OpKind == OO_LessLessEqual || OpKind == OO_GreaterGreaterEqual ||
49  OpKind == OO_PlusPlus || OpKind == OO_MinusMinus ||
50  OpKind == OO_PercentEqual || OpKind == OO_New ||
51  OpKind == OO_Delete || OpKind == OO_Array_New ||
52  OpKind == OO_Array_Delete;
53  }
54 
55  if (const auto *CExpr = dyn_cast<CallExpr>(E)) {
56  bool Result = CheckFunctionCalls;
57  if (const auto *FuncDecl = CExpr->getDirectCallee()) {
58  if (FuncDecl->getDeclName().isIdentifier() &&
59  FuncDecl->getName() == "__builtin_expect") // exceptions come here
60  Result = false;
61  else if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(FuncDecl))
62  Result &= !MethodDecl->isConst();
63  }
64  return Result;
65  }
66 
67  return isa<CXXNewExpr>(E) || isa<CXXDeleteExpr>(E) || isa<CXXThrowExpr>(E);
68 }
69 
70 } // namespace
71 
72 AssertSideEffectCheck::AssertSideEffectCheck(StringRef Name,
74  : ClangTidyCheck(Name, Context),
75  CheckFunctionCalls(Options.get("CheckFunctionCalls", false)),
76  RawAssertList(Options.get("AssertMacros", "assert")) {
77  StringRef(RawAssertList).split(AssertMacros, ",", -1, false);
78 }
79 
80 // The options are explained in AssertSideEffectCheck.h.
82  Options.store(Opts, "CheckFunctionCalls", CheckFunctionCalls);
83  Options.store(Opts, "AssertMacros", RawAssertList);
84 }
85 
87  auto DescendantWithSideEffect =
88  hasDescendant(expr(hasSideEffect(CheckFunctionCalls)));
89  auto ConditionWithSideEffect = hasCondition(DescendantWithSideEffect);
90  Finder->addMatcher(
91  stmt(
92  anyOf(conditionalOperator(ConditionWithSideEffect),
93  ifStmt(ConditionWithSideEffect),
94  unaryOperator(hasOperatorName("!"),
95  hasUnaryOperand(unaryOperator(
96  hasOperatorName("!"),
97  hasUnaryOperand(DescendantWithSideEffect))))))
98  .bind("condStmt"),
99  this);
100 }
101 
102 void AssertSideEffectCheck::check(const MatchFinder::MatchResult &Result) {
103  const SourceManager &SM = *Result.SourceManager;
104  const LangOptions LangOpts = getLangOpts();
105  SourceLocation Loc = Result.Nodes.getNodeAs<Stmt>("condStmt")->getLocStart();
106 
107  StringRef AssertMacroName;
108  while (Loc.isValid() && Loc.isMacroID()) {
109  StringRef MacroName = Lexer::getImmediateMacroName(Loc, SM, LangOpts);
110 
111  // Check if this macro is an assert.
112  if (std::find(AssertMacros.begin(), AssertMacros.end(), MacroName) !=
113  AssertMacros.end()) {
114  AssertMacroName = MacroName;
115  break;
116  }
117  Loc = SM.getImmediateMacroCallerLoc(Loc);
118  }
119  if (AssertMacroName.empty())
120  return;
121 
122  diag(Loc, "found %0() with side effect") << AssertMacroName;
123 }
124 
125 } // namespace misc
126 } // namespace tidy
127 } // namespace clang
SourceLocation Loc
'#' location in the include directive
const std::string Name
Definition: USRFinder.cpp:164
LangOptions LangOpts
Definition: ClangTidy.cpp:240
LangOptions getLangOpts() const
Returns the language options from the context.
Definition: ClangTidy.h:187
std::unique_ptr< ast_matchers::MatchFinder > Finder
Definition: ClangTidy.cpp:262
AST_MATCHER_P(CXXForRangeStmt, hasRangeBeginEndStmt, ast_matchers::internal::Matcher< DeclStmt >, InnerMatcher)
Base class for all clang-tidy checks.
Definition: ClangTidy.h:127
SourceManager & SM
void store(ClangTidyOptions::OptionMap &Options, StringRef LocalName, StringRef Value) const
Stores an option with the check-local name LocalName with string value Value to Options.
Definition: ClangTidy.cpp:436
std::map< std::string, std::string > OptionMap
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
ClangTidyContext & Context
Definition: ClangTidy.cpp:87
void storeOptions(ClangTidyOptions::OptionMap &Opts) override
Should store all options supported by this check with their current values or default values for opti...
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check's name.
Definition: ClangTidy.cpp:403
const NamedDecl * Result
Definition: USRFinder.cpp:162