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 "llvm/Support/Casting.h"
19#include <algorithm>
20#include <string>
21
22using namespace clang::ast_matchers;
23
24namespace clang::tidy::bugprone {
25
26namespace {
27
28AST_MATCHER_P2(Expr, hasSideEffect, bool, CheckFunctionCalls,
29 clang::ast_matchers::internal::Matcher<NamedDecl>,
30 IgnoredFunctionsMatcher) {
31 const Expr *E = &Node;
32
33 if (const auto *Op = dyn_cast<UnaryOperator>(Val: E)) {
34 UnaryOperator::Opcode OC = Op->getOpcode();
35 return OC == UO_PostInc || OC == UO_PostDec || OC == UO_PreInc ||
36 OC == UO_PreDec;
37 }
38
39 if (const auto *Op = dyn_cast<BinaryOperator>(Val: E)) {
40 return Op->isAssignmentOp();
41 }
42
43 if (const auto *OpCallExpr = dyn_cast<CXXOperatorCallExpr>(Val: E)) {
44 if (const auto *MethodDecl =
45 dyn_cast_or_null<CXXMethodDecl>(OpCallExpr->getDirectCallee()))
46 if (MethodDecl->isConst())
47 return false;
48
49 OverloadedOperatorKind OpKind = OpCallExpr->getOperator();
50 return OpKind == OO_Equal || OpKind == OO_PlusEqual ||
51 OpKind == OO_MinusEqual || OpKind == OO_StarEqual ||
52 OpKind == OO_SlashEqual || OpKind == OO_AmpEqual ||
53 OpKind == OO_PipeEqual || OpKind == OO_CaretEqual ||
54 OpKind == OO_LessLessEqual || OpKind == OO_GreaterGreaterEqual ||
55 OpKind == OO_LessLess || OpKind == OO_GreaterGreater ||
56 OpKind == OO_PlusPlus || OpKind == OO_MinusMinus ||
57 OpKind == OO_PercentEqual || OpKind == OO_New ||
58 OpKind == OO_Delete || OpKind == OO_Array_New ||
59 OpKind == OO_Array_Delete;
60 }
61
62 if (const auto *CExpr = dyn_cast<CallExpr>(Val: E)) {
63 if (!CheckFunctionCalls)
64 return false;
65 if (const auto *FuncDecl = CExpr->getDirectCallee()) {
66 if (FuncDecl->getDeclName().isIdentifier() &&
67 IgnoredFunctionsMatcher.matches(*FuncDecl, Finder,
68 Builder)) // exceptions come here
69 return false;
70 for (size_t I = 0; I < FuncDecl->getNumParams(); I++) {
71 const ParmVarDecl *P = FuncDecl->getParamDecl(i: I);
72 const Expr *ArgExpr =
73 I < CExpr->getNumArgs() ? CExpr->getArg(Arg: I) : nullptr;
74 const QualType PT = P->getType().getCanonicalType();
75 if (ArgExpr && !ArgExpr->isXValue() && PT->isReferenceType() &&
76 !PT.getNonReferenceType().isConstQualified())
77 return true;
78 }
79 if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(Val: FuncDecl))
80 return !MethodDecl->isConst();
81 }
82 return true;
83 }
84
85 return isa<CXXNewExpr>(Val: E) || isa<CXXDeleteExpr>(Val: E) || isa<CXXThrowExpr>(Val: E);
86}
87
88} // namespace
89
90AssertSideEffectCheck::AssertSideEffectCheck(StringRef Name,
91 ClangTidyContext *Context)
92 : ClangTidyCheck(Name, Context),
93 CheckFunctionCalls(Options.get(LocalName: "CheckFunctionCalls", Default: false)),
94 RawAssertList(Options.get(LocalName: "AssertMacros", Default: "assert,NSAssert,NSCAssert")),
95 IgnoredFunctions(utils::options::parseListPair(
96 L: "__builtin_expect;", R: Options.get(LocalName: "IgnoredFunctions", Default: ""))) {
97 StringRef(RawAssertList).split(A&: AssertMacros, Separator: ",", MaxSplit: -1, KeepEmpty: false);
98}
99
100// The options are explained in AssertSideEffectCheck.h.
101void AssertSideEffectCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
102 Options.store(Options&: Opts, LocalName: "CheckFunctionCalls", Value: CheckFunctionCalls);
103 Options.store(Options&: Opts, LocalName: "AssertMacros", Value: RawAssertList);
104 Options.store(Options&: Opts, LocalName: "IgnoredFunctions",
105 Value: utils::options::serializeStringList(Strings: IgnoredFunctions));
106}
107
108void AssertSideEffectCheck::registerMatchers(MatchFinder *Finder) {
109 auto IgnoredFunctionsMatcher =
110 matchers::matchesAnyListedName(NameList: IgnoredFunctions);
111
112 auto DescendantWithSideEffect =
113 traverse(TK: TK_AsIs, InnerMatcher: hasDescendant(expr(hasSideEffect(
114 CheckFunctionCalls, IgnoredFunctionsMatcher))));
115 auto ConditionWithSideEffect = hasCondition(InnerMatcher: DescendantWithSideEffect);
116 Finder->addMatcher(
117 NodeMatch: stmt(
118 anyOf(conditionalOperator(ConditionWithSideEffect),
119 ifStmt(ConditionWithSideEffect),
120 unaryOperator(hasOperatorName(Name: "!"),
121 hasUnaryOperand(InnerMatcher: unaryOperator(
122 hasOperatorName(Name: "!"),
123 hasUnaryOperand(InnerMatcher: DescendantWithSideEffect))))))
124 .bind(ID: "condStmt"),
125 Action: this);
126}
127
128void AssertSideEffectCheck::check(const MatchFinder::MatchResult &Result) {
129 const SourceManager &SM = *Result.SourceManager;
130 const LangOptions LangOpts = getLangOpts();
131 SourceLocation Loc = Result.Nodes.getNodeAs<Stmt>(ID: "condStmt")->getBeginLoc();
132
133 StringRef AssertMacroName;
134 while (Loc.isValid() && Loc.isMacroID()) {
135 StringRef MacroName = Lexer::getImmediateMacroName(Loc, SM, LangOpts);
136 Loc = SM.getImmediateMacroCallerLoc(Loc);
137
138 // Check if this macro is an assert.
139 if (llvm::is_contained(Range&: AssertMacros, Element: MacroName)) {
140 AssertMacroName = MacroName;
141 break;
142 }
143 }
144 if (AssertMacroName.empty())
145 return;
146
147 diag(Loc, Description: "side effect in %0() condition discarded in release builds")
148 << AssertMacroName;
149}
150
151} // namespace clang::tidy::bugprone
152

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