clang-tools 6.0.0

InefficientStringConcatenationCheck.cpp
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1 //===--- InefficientStringConcatenationCheck.cpp - clang-tidy--------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "InefficientStringConcatenationCheck.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13
14 using namespace clang::ast_matchers;
15
16 namespace clang {
17 namespace tidy {
18 namespace performance {
19
20 void InefficientStringConcatenationCheck::storeOptions(
21 ClangTidyOptions::OptionMap &Opts) {
22 Options.store(Opts, "StrictMode", StrictMode);
23 }
24
25 InefficientStringConcatenationCheck::InefficientStringConcatenationCheck(
26 StringRef Name, ClangTidyContext *Context)
27 : ClangTidyCheck(Name, Context),
28 StrictMode(Options.getLocalOrGlobal("StrictMode", 0)) {}
29
30 void InefficientStringConcatenationCheck::registerMatchers(
31 MatchFinder *Finder) {
32 if (!getLangOpts().CPlusPlus)
33 return;
34
35 const auto BasicStringType =
36 hasType(qualType(hasUnqualifiedDesugaredType(recordType(
37 hasDeclaration(cxxRecordDecl(hasName("::std::basic_string")))))));
38
39 const auto BasicStringPlusOperator = cxxOperatorCallExpr(
40 hasOverloadedOperatorName("+"),
41 hasAnyArgument(ignoringImpCasts(declRefExpr(BasicStringType))));
42
43 const auto PlusOperator =
44 cxxOperatorCallExpr(
45 hasOverloadedOperatorName("+"),
46 hasAnyArgument(ignoringImpCasts(declRefExpr(BasicStringType))),
47 hasDescendant(BasicStringPlusOperator))
48 .bind("plusOperator");
49
50 const auto AssignOperator = cxxOperatorCallExpr(
51 hasOverloadedOperatorName("="),
52 hasArgument(0, declRefExpr(BasicStringType,
53 hasDeclaration(decl().bind("lhsStrT")))
54 .bind("lhsStr")),
55 hasArgument(1, stmt(hasDescendant(declRefExpr(
56 hasDeclaration(decl(equalsBoundNode("lhsStrT"))))))),
57 hasDescendant(BasicStringPlusOperator));
58
59 if (StrictMode) {
60 Finder->addMatcher(cxxOperatorCallExpr(anyOf(AssignOperator, PlusOperator)),
61 this);
62 } else {
63 Finder->addMatcher(
64 cxxOperatorCallExpr(anyOf(AssignOperator, PlusOperator),
65 hasAncestor(stmt(anyOf(cxxForRangeStmt(),
66 whileStmt(), forStmt())))),
67 this);
68 }
69 }
70
71 void InefficientStringConcatenationCheck::check(
72 const MatchFinder::MatchResult &Result) {
73 const auto *LhsStr = Result.Nodes.getNodeAs<DeclRefExpr>("lhsStr");
74 const auto *PlusOperator =
75 Result.Nodes.getNodeAs<CXXOperatorCallExpr>("plusOperator");
76 const auto DiagMsg =
77 "string concatenation results in allocation of unnecessary temporary "
78 "strings; consider using 'operator+=' or 'string::append()' instead";
79
80 if (LhsStr)
81 diag(LhsStr->getExprLoc(), DiagMsg);
82 else if (PlusOperator)
83 diag(PlusOperator->getExprLoc(), DiagMsg);
84 }
85
86 } // namespace performance
87 } // namespace tidy
88 } // namespace clang
clang::ast_matchers
Definition: ClangTidyDiagnosticConsumer.h:27
Name
StringHandle Name
Definition: PreprocessorTracker.cpp:525
clang::tidy::ClangTidyCheck::getLangOpts
LangOptions getLangOpts() const
Returns the language options from the context.
Definition: ClangTidy.h:187
clang::tidy::performance::InefficientStringConcatenationCheck::registerMatchers
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
Definition: InefficientStringConcatenationCheck.cpp:30
clang::tidy::ClangTidyCheck
Base class for all clang-tidy checks.
Definition: ClangTidy.h:127
InefficientStringConcatenationCheck.h
clang::tidy::ClangTidyOptions::OptionMap
std::map< std::string, std::string > OptionMap
Definition: ClangTidyOptions.h:99
clang
Definition: AndroidTidyModule.cpp:28
clang::tidy::ClangTidyContext
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
Definition: ClangTidyDiagnosticConsumer.h:104
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:71
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: ClangTidy.cpp:416