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Alexander Kornienkodcbf57d2016-08-03 23:06:03 +00001//===--- 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
14using namespace clang::ast_matchers;
15
16namespace clang {
17namespace tidy {
18namespace performance {
19
20void InefficientStringConcatenationCheck::storeOptions(
21 ClangTidyOptions::OptionMap &Opts) {
22 Options.store(Opts, "StrictMode", StrictMode);
23}
24
25InefficientStringConcatenationCheck::InefficientStringConcatenationCheck(
26 StringRef Name, ClangTidyContext *Context)
Alexander Kornienko0055d972017-05-29 13:59:27 +000027 : ClangTidyCheck(Name, Context),
28 StrictMode(Options.getLocalOrGlobal("StrictMode", 0)) {}
Alexander Kornienkodcbf57d2016-08-03 23:06:03 +000029
30void InefficientStringConcatenationCheck::registerMatchers(
31 MatchFinder *Finder) {
32 if (!getLangOpts().CPlusPlus)
33 return;
34
35 const auto BasicStringType =
Manuel Klimek7b9c1172017-08-02 13:13:11 +000036 hasType(qualType(hasUnqualifiedDesugaredType(recordType(
37 hasDeclaration(cxxRecordDecl(hasName("::std::basic_string")))))));
Alexander Kornienkodcbf57d2016-08-03 23:06:03 +000038
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
71void 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