1//===--- AssertSideEffectCheck.cpp - clang-tidy ---------------------------===//
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
9#include "AssertSideEffectCheck.h"
10#include "../utils/Matchers.h"
11#include "../utils/OptionsUtils.h"
12#include "clang/AST/ASTContext.h"
13#include "clang/ASTMatchers/ASTMatchFinder.h"
14#include "clang/Frontend/CompilerInstance.h"
15#include "clang/Lex/Lexer.h"
16#include "llvm/ADT/SmallVector.h"
17#include "llvm/ADT/StringRef.h"
18#include <string>
19
20using namespace clang::ast_matchers;
21
22namespace clang::tidy::bugprone {
23
24namespace {
25
26AST_MATCHER_P2(Expr, hasSideEffect, bool, CheckFunctionCalls,
27 clang::ast_matchers::internal::Matcher<NamedDecl>,
28 IgnoredFunctionsMatcher) {
29 const Expr *E = &Node;
30
31 if (const auto *Op = dyn_cast<UnaryOperator>(Val: E)) {
32 UnaryOperator::Opcode OC = Op->getOpcode();
33 return OC == UO_PostInc || OC == UO_PostDec || OC == UO_PreInc ||
34 OC == UO_PreDec;
35 }
36
37 if (const auto *Op = dyn_cast<BinaryOperator>(Val: E)) {
38 return Op->isAssignmentOp();
39 }
40
41 if (const auto *OpCallExpr = dyn_cast<CXXOperatorCallExpr>(Val: E)) {
42 if (const auto *MethodDecl =
43 dyn_cast_or_null<CXXMethodDecl>(OpCallExpr->getDirectCallee()))
44 if (MethodDecl->isConst())
45 return false;
46
47 OverloadedOperatorKind OpKind = OpCallExpr->getOperator();
48 return OpKind == OO_Equal || OpKind == OO_PlusEqual ||
49 OpKind == OO_MinusEqual || OpKind == OO_StarEqual ||
50 OpKind == OO_SlashEqual || OpKind == OO_AmpEqual ||
51 OpKind == OO_PipeEqual || OpKind == OO_CaretEqual ||
52 OpKind == OO_LessLessEqual || OpKind == OO_GreaterGreaterEqual ||
53 OpKind == OO_LessLess || OpKind == OO_GreaterGreater ||
54 OpKind == OO_PlusPlus || OpKind == OO_MinusMinus ||
55 OpKind == OO_PercentEqual || OpKind == OO_New ||
56 OpKind == OO_Delete || OpKind == OO_Array_New ||
57 OpKind == OO_Array_Delete;
58 }
59
60 if (const auto *CExpr = dyn_cast<CallExpr>(Val: E)) {
61 if (!CheckFunctionCalls)
62 return false;
63 if (const auto *FuncDecl = CExpr->getDirectCallee()) {
64 if (FuncDecl->getDeclName().isIdentifier() &&
65 IgnoredFunctionsMatcher.matches(*FuncDecl, Finder,
66 Builder)) // exceptions come here
67 return false;
68 for (size_t I = 0; I < FuncDecl->getNumParams(); I++) {
69 const ParmVarDecl *P = FuncDecl->getParamDecl(i: I);
70 const Expr *ArgExpr =
71 I < CExpr->getNumArgs() ? CExpr->getArg(Arg: I) : nullptr;
72 const QualType PT = P->getType().getCanonicalType();
73 if (ArgExpr && !ArgExpr->isXValue() && PT->isReferenceType() &&
74 !PT.getNonReferenceType().isConstQualified())
75 return true;
76 }
77 if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(Val: FuncDecl))
78 return !MethodDecl->isConst();
79 }
80 return true;
81 }
82
83 return isa<CXXNewExpr>(Val: E) || isa<CXXDeleteExpr>(Val: E) || isa<CXXThrowExpr>(Val: E);
84}
85
86} // namespace
87
88AssertSideEffectCheck::AssertSideEffectCheck(StringRef Name,
89 ClangTidyContext *Context)
90 : ClangTidyCheck(Name, Context),
91 CheckFunctionCalls(Options.get(LocalName: "CheckFunctionCalls", Default: false)),
92 RawAssertList(Options.get(LocalName: "AssertMacros", Default: "assert,NSAssert,NSCAssert")),
93 IgnoredFunctions(utils::options::parseListPair(
94 L: "__builtin_expect;", R: Options.get(LocalName: "IgnoredFunctions", Default: ""))) {
95 StringRef(RawAssertList).split(A&: AssertMacros, Separator: ",", MaxSplit: -1, KeepEmpty: false);
96}
97
98// The options are explained in AssertSideEffectCheck.h.
99void AssertSideEffectCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
100 Options.store(Options&: Opts, LocalName: "CheckFunctionCalls", Value: CheckFunctionCalls);
101 Options.store(Options&: Opts, LocalName: "AssertMacros", Value: RawAssertList);
102 Options.store(Options&: Opts, LocalName: "IgnoredFunctions",
103 Value: utils::options::serializeStringList(Strings: IgnoredFunctions));
104}
105
106void AssertSideEffectCheck::registerMatchers(MatchFinder *Finder) {
107 auto IgnoredFunctionsMatcher =
108 matchers::matchesAnyListedName(NameList: IgnoredFunctions);
109
110 auto DescendantWithSideEffect =
111 traverse(TK: TK_AsIs, InnerMatcher: hasDescendant(expr(hasSideEffect(
112 CheckFunctionCalls, IgnoredFunctionsMatcher))));
113 auto ConditionWithSideEffect = hasCondition(InnerMatcher: DescendantWithSideEffect);
114 Finder->addMatcher(
115 NodeMatch: stmt(
116 anyOf(conditionalOperator(ConditionWithSideEffect),
117 ifStmt(ConditionWithSideEffect),
118 unaryOperator(hasOperatorName(Name: "!"),
119 hasUnaryOperand(InnerMatcher: unaryOperator(
120 hasOperatorName(Name: "!"),
121 hasUnaryOperand(InnerMatcher: DescendantWithSideEffect))))))
122 .bind(ID: "condStmt"),
123 Action: this);
124}
125
126void AssertSideEffectCheck::check(const MatchFinder::MatchResult &Result) {
127 const SourceManager &SM = *Result.SourceManager;
128 const LangOptions LangOpts = getLangOpts();
129 SourceLocation Loc = Result.Nodes.getNodeAs<Stmt>(ID: "condStmt")->getBeginLoc();
130
131 StringRef AssertMacroName;
132 while (Loc.isValid() && Loc.isMacroID()) {
133 StringRef MacroName = Lexer::getImmediateMacroName(Loc, SM, LangOpts);
134 Loc = SM.getImmediateMacroCallerLoc(Loc);
135
136 // Check if this macro is an assert.
137 if (llvm::is_contained(Range&: AssertMacros, Element: MacroName)) {
138 AssertMacroName = MacroName;
139 break;
140 }
141 }
142 if (AssertMacroName.empty())
143 return;
144
145 diag(Loc, Description: "side effect in %0() condition discarded in release builds")
146 << AssertMacroName;
147}
148
149} // namespace clang::tidy::bugprone
150

source code of clang-tools-extra/clang-tidy/bugprone/AssertSideEffectCheck.cpp