clang-tools 10.0.0

InefficientStringConcatenationCheck.cpp
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1 //===--- InefficientStringConcatenationCheck.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 "InefficientStringConcatenationCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12
13 using namespace clang::ast_matchers;
14
15 namespace clang {
16 namespace tidy {
17 namespace performance {
18
19 void InefficientStringConcatenationCheck::storeOptions(
20 ClangTidyOptions::OptionMap &Opts) {
21 Options.store(Opts, "StrictMode", StrictMode);
22 }
23
24 InefficientStringConcatenationCheck::InefficientStringConcatenationCheck(
25 StringRef Name, ClangTidyContext *Context)
26 : ClangTidyCheck(Name, Context),
27 StrictMode(Options.getLocalOrGlobal("StrictMode", 0)) {}
28
29 void InefficientStringConcatenationCheck::registerMatchers(
30 MatchFinder *Finder) {
31 if (!getLangOpts().CPlusPlus)
32 return;
33
34 const auto BasicStringType =
35 hasType(qualType(hasUnqualifiedDesugaredType(recordType(
36 hasDeclaration(cxxRecordDecl(hasName("::std::basic_string")))))));
37
38 const auto BasicStringPlusOperator = cxxOperatorCallExpr(
39 hasOverloadedOperatorName("+"),
40 hasAnyArgument(ignoringImpCasts(declRefExpr(BasicStringType))));
41
42 const auto PlusOperator =
43 cxxOperatorCallExpr(
44 hasOverloadedOperatorName("+"),
45 hasAnyArgument(ignoringImpCasts(declRefExpr(BasicStringType))),
46 hasDescendant(BasicStringPlusOperator))
47 .bind("plusOperator");
48
49 const auto AssignOperator = cxxOperatorCallExpr(
50 hasOverloadedOperatorName("="),
51 hasArgument(0, declRefExpr(BasicStringType,
52 hasDeclaration(decl().bind("lhsStrT")))
53 .bind("lhsStr")),
54 hasArgument(1, stmt(hasDescendant(declRefExpr(
55 hasDeclaration(decl(equalsBoundNode("lhsStrT"))))))),
56 hasDescendant(BasicStringPlusOperator));
57
58 if (StrictMode) {
59 Finder->addMatcher(cxxOperatorCallExpr(anyOf(AssignOperator, PlusOperator)),
60 this);
61 } else {
62 Finder->addMatcher(
63 cxxOperatorCallExpr(anyOf(AssignOperator, PlusOperator),
64 hasAncestor(stmt(anyOf(cxxForRangeStmt(),
65 whileStmt(), forStmt())))),
66 this);
67 }
68 }
69
70 void InefficientStringConcatenationCheck::check(
71 const MatchFinder::MatchResult &Result) {
72 const auto *LhsStr = Result.Nodes.getNodeAs<DeclRefExpr>("lhsStr");
73 const auto *PlusOperator =
74 Result.Nodes.getNodeAs<CXXOperatorCallExpr>("plusOperator");
75 const auto DiagMsg =
76 "string concatenation results in allocation of unnecessary temporary "
77 "strings; consider using 'operator+=' or 'string::append()' instead";
78
79 if (LhsStr)
80 diag(LhsStr->getExprLoc(), DiagMsg);
81 else if (PlusOperator)
82 diag(PlusOperator->getExprLoc(), DiagMsg);
83 }
84
85 } // namespace performance
86 } // namespace tidy
87 } // namespace clang
clang::ast_matchers
Definition: AbseilMatcher.h:14
clang::tidy::performance::InefficientStringConcatenationCheck::registerMatchers
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
Definition: InefficientStringConcatenationCheck.cpp:29
clang::tidy::ClangTidyCheck
Base class for all clang-tidy checks.
Definition: ClangTidyCheck.h:47
clang::tidy::ClangTidyCheck::getLangOpts
const LangOptions & getLangOpts() const
Returns the language options from the context.
Definition: ClangTidyCheck.h:188
InefficientStringConcatenationCheck.h
Name
static constexpr llvm::StringLiteral Name
Definition: UppercaseLiteralSuffixCheck.cpp:27
clang::tidy::ClangTidyOptions::OptionMap
std::map< std::string, std::string > OptionMap
Definition: ClangTidyOptions.h:97
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
clang::tidy::ClangTidyContext
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
Definition: ClangTidyDiagnosticConsumer.h:77
clang::tidy::performance::InefficientStringConcatenationCheck::check
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
Definition: InefficientStringConcatenationCheck.cpp:70
clang::tidy::ClangTidyCheck::diag
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check&#39;s name.
Definition: ClangTidyCheck.cpp:21