clang-tools 18.0.0git
PosixReturnCheck.cpp
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1//===--- PosixReturnCheck.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 "PosixReturnCheck.h"
10#include "../utils/Matchers.h"
11#include "clang/AST/ASTContext.h"
12#include "clang/ASTMatchers/ASTMatchFinder.h"
13#include "clang/Lex/Lexer.h"
14
15using namespace clang::ast_matchers;
16
17namespace clang::tidy::bugprone {
18
19static StringRef getFunctionSpelling(const MatchFinder::MatchResult &Result,
20 const char *BindingStr) {
21 const CallExpr *MatchedCall = cast<CallExpr>(
22 (Result.Nodes.getNodeAs<BinaryOperator>(BindingStr))->getLHS());
23 const SourceManager &SM = *Result.SourceManager;
24 return Lexer::getSourceText(CharSourceRange::getTokenRange(
25 MatchedCall->getCallee()->getSourceRange()),
26 SM, Result.Context->getLangOpts());
27}
28
29void PosixReturnCheck::registerMatchers(MatchFinder *Finder) {
30 Finder->addMatcher(
31 binaryOperator(
32 hasOperatorName("<"),
33 hasLHS(callExpr(callee(functionDecl(
34 anyOf(matchesName("^::posix_"), matchesName("^::pthread_")),
35 unless(hasName("::posix_openpt")))))),
36 hasRHS(integerLiteral(equals(0))))
37 .bind("ltzop"),
38 this);
39 Finder->addMatcher(
40 binaryOperator(
41 hasOperatorName(">="),
42 hasLHS(callExpr(callee(functionDecl(
43 anyOf(matchesName("^::posix_"), matchesName("^::pthread_")),
44 unless(hasName("::posix_openpt")))))),
45 hasRHS(integerLiteral(equals(0))))
46 .bind("atop"),
47 this);
48 Finder->addMatcher(
49 binaryOperator(
50 hasAnyOperatorName("==", "!=", "<=", "<"),
51 hasLHS(callExpr(callee(functionDecl(
52 anyOf(matchesName("^::posix_"), matchesName("^::pthread_")),
53 unless(hasName("::posix_openpt")))))),
54 hasRHS(unaryOperator(hasOperatorName("-"),
55 hasUnaryOperand(integerLiteral()))))
56 .bind("binop"),
57 this);
58}
59
60void PosixReturnCheck::check(const MatchFinder::MatchResult &Result) {
61 if (const auto *LessThanZeroOp =
62 Result.Nodes.getNodeAs<BinaryOperator>("ltzop")) {
63 SourceLocation OperatorLoc = LessThanZeroOp->getOperatorLoc();
64 diag(OperatorLoc, "the comparison always evaluates to false because %0 "
65 "always returns non-negative values")
66 << getFunctionSpelling(Result, "ltzop")
67 << FixItHint::CreateReplacement(OperatorLoc, Twine(">").str());
68 return;
69 }
70 if (const auto *AlwaysTrueOp =
71 Result.Nodes.getNodeAs<BinaryOperator>("atop")) {
72 diag(AlwaysTrueOp->getOperatorLoc(),
73 "the comparison always evaluates to true because %0 always returns "
74 "non-negative values")
75 << getFunctionSpelling(Result, "atop");
76 return;
77 }
78 const auto *BinOp = Result.Nodes.getNodeAs<BinaryOperator>("binop");
79 diag(BinOp->getOperatorLoc(), "%0 only returns non-negative values")
80 << getFunctionSpelling(Result, "binop");
81}
82
83} // namespace clang::tidy::bugprone
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check's name.
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
static StringRef getFunctionSpelling(const MatchFinder::MatchResult &Result, const char *BindingStr)