clang-tools  8.0.0
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 
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(
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 
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 
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
LangOptions getLangOpts() const
Returns the language options from the context.
Definition: ClangTidy.h:187
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
Base class for all clang-tidy checks.
Definition: ClangTidy.h:127
static constexpr llvm::StringLiteral Name
std::map< std::string, std::string > OptionMap
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check&#39;s name.
Definition: ClangTidy.cpp:438