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 "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/Frontend/CompilerInstance.h"
13 #include "clang/Lex/Lexer.h"
14 #include "llvm/ADT/SmallVector.h"
15 #include "llvm/ADT/StringRef.h"
16 #include "llvm/Support/Casting.h"
17 #include <algorithm>
18 #include <string>
19
20 using namespace clang::ast_matchers;
21
22 namespace clang {
23 namespace tidy {
24 namespace bugprone {
25
26 namespace {
27
AST_MATCHER_P(Expr,hasSideEffect,bool,CheckFunctionCalls)28 AST_MATCHER_P(Expr, hasSideEffect, bool, CheckFunctionCalls) {
29 const Expr *E = &Node;
30
31 if (const auto *Op = dyn_cast<UnaryOperator>(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>(E)) {
38 return Op->isAssignmentOp();
39 }
40
41 if (const auto *OpCallExpr = dyn_cast<CXXOperatorCallExpr>(E)) {
42 OverloadedOperatorKind OpKind = OpCallExpr->getOperator();
43 return OpKind == OO_Equal || OpKind == OO_PlusEqual ||
44 OpKind == OO_MinusEqual || OpKind == OO_StarEqual ||
45 OpKind == OO_SlashEqual || OpKind == OO_AmpEqual ||
46 OpKind == OO_PipeEqual || OpKind == OO_CaretEqual ||
47 OpKind == OO_LessLessEqual || OpKind == OO_GreaterGreaterEqual ||
48 OpKind == OO_PlusPlus || OpKind == OO_MinusMinus ||
49 OpKind == OO_PercentEqual || OpKind == OO_New ||
50 OpKind == OO_Delete || OpKind == OO_Array_New ||
51 OpKind == OO_Array_Delete;
52 }
53
54 if (const auto *CExpr = dyn_cast<CallExpr>(E)) {
55 bool Result = CheckFunctionCalls;
56 if (const auto *FuncDecl = CExpr->getDirectCallee()) {
57 if (FuncDecl->getDeclName().isIdentifier() &&
58 FuncDecl->getName() == "__builtin_expect") // exceptions come here
59 Result = false;
60 else if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(FuncDecl))
61 Result &= !MethodDecl->isConst();
62 }
63 return Result;
64 }
65
66 return isa<CXXNewExpr>(E) || isa<CXXDeleteExpr>(E) || isa<CXXThrowExpr>(E);
67 }
68
69 } // namespace
70
AssertSideEffectCheck(StringRef Name,ClangTidyContext * Context)71 AssertSideEffectCheck::AssertSideEffectCheck(StringRef Name,
72 ClangTidyContext *Context)
73 : ClangTidyCheck(Name, Context),
74 CheckFunctionCalls(Options.get("CheckFunctionCalls", false)),
75 RawAssertList(Options.get("AssertMacros", "assert")) {
76 StringRef(RawAssertList).split(AssertMacros, ",", -1, false);
77 }
78
79 // The options are explained in AssertSideEffectCheck.h.
storeOptions(ClangTidyOptions::OptionMap & Opts)80 void AssertSideEffectCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
81 Options.store(Opts, "CheckFunctionCalls", CheckFunctionCalls);
82 Options.store(Opts, "AssertMacros", RawAssertList);
83 }
84
registerMatchers(MatchFinder * Finder)85 void AssertSideEffectCheck::registerMatchers(MatchFinder *Finder) {
86 auto DescendantWithSideEffect =
87 traverse(ast_type_traits::TK_AsIs,
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
check(const MatchFinder::MatchResult & Result)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")->getBeginLoc();
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 (llvm::is_contained(AssertMacros, MacroName)) {
113 AssertMacroName = MacroName;
114 break;
115 }
116 Loc = SM.getImmediateMacroCallerLoc(Loc);
117 }
118 if (AssertMacroName.empty())
119 return;
120
121 diag(Loc, "found %0() with side effect") << AssertMacroName;
122 }
123
124 } // namespace bugprone
125 } // namespace tidy
126 } // namespace clang
127