clang-tools 20.0.0git
AvoidEndlCheck.cpp
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1//===--- AvoidEndlCheck.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 "AvoidEndlCheck.h"
10#include "clang/AST/ASTContext.h"
11#include "clang/AST/DeclCXX.h"
12#include "clang/AST/Expr.h"
13#include "clang/AST/ExprCXX.h"
14#include "clang/ASTMatchers/ASTMatchFinder.h"
15#include "clang/ASTMatchers/ASTMatchers.h"
16#include "clang/Lex/Lexer.h"
17
18using namespace clang::ast_matchers;
19
21
22void AvoidEndlCheck::registerMatchers(MatchFinder *Finder) {
23 Finder->addMatcher(
24 callExpr(
25 unless(isExpansionInSystemHeader()),
26 anyOf(cxxOperatorCallExpr(
27 hasOverloadedOperatorName("<<"),
28 hasRHS(declRefExpr(to(namedDecl(hasName("::std::endl"))))
29 .bind("expr"))),
30 callExpr(argumentCountIs(1),
31 callee(functionDecl(hasName("::std::endl"))))
32 .bind("expr"))),
33 this);
34}
35
36void AvoidEndlCheck::check(const MatchFinder::MatchResult &Result) {
37 const auto *Expression = Result.Nodes.getNodeAs<Expr>("expr");
38 assert(Expression);
39 assert(isa<DeclRefExpr>(Expression) || isa<CallExpr>(Expression));
40
41 // FIXME: It would be great if we could transform
42 // 'std::cout << "Hi" << std::endl;' into
43 // 'std::cout << "Hi\n"';
44
45 if (llvm::isa<DeclRefExpr>(Expression)) {
46 // Handle the more common streaming '... << std::endl' case
47 const CharSourceRange TokenRange =
48 CharSourceRange::getTokenRange(Expression->getSourceRange());
49 const StringRef SourceText = Lexer::getSourceText(
50 TokenRange, *Result.SourceManager, Result.Context->getLangOpts());
51
52 auto Diag = diag(Expression->getBeginLoc(),
53 "do not use '%0' with streams; use '\\n' instead")
54 << SourceText;
55
56 Diag << FixItHint::CreateReplacement(TokenRange, "'\\n'");
57 } else {
58 // Handle the less common function call 'std::endl(...)' case
59 const auto *CallExpression = llvm::cast<CallExpr>(Expression);
60 assert(CallExpression->getNumArgs() == 1);
61
62 const StringRef SourceText = Lexer::getSourceText(
63 CharSourceRange::getTokenRange(
64 CallExpression->getCallee()->getSourceRange()),
65 *Result.SourceManager, Result.Context->getLangOpts());
66
67 const CharSourceRange ArgTokenRange = CharSourceRange::getTokenRange(
68 CallExpression->getArg(0)->getSourceRange());
69 const StringRef ArgSourceText = Lexer::getSourceText(
70 ArgTokenRange, *Result.SourceManager, Result.Context->getLangOpts());
71
72 const std::string ReplacementString =
73 std::string(ArgSourceText) + " << '\\n'";
74
75 diag(CallExpression->getBeginLoc(),
76 "do not use '%0' with streams; use '\\n' instead")
77 << SourceText
78 << FixItHint::CreateReplacement(
79 CharSourceRange::getTokenRange(CallExpression->getSourceRange()),
80 ReplacementString);
81 }
82}
83
84} // namespace clang::tidy::performance
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check's name.
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.