clang-tools  8.0.0
ShrinkToFitCheck.cpp
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1 //===--- ShrinkToFitCheck.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 "ShrinkToFitCheck.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/Lex/Lexer.h"
14 #include "llvm/ADT/StringRef.h"
15 
16 using namespace clang::ast_matchers;
17 
18 namespace clang {
19 namespace tidy {
20 namespace modernize {
21 
22 void ShrinkToFitCheck::registerMatchers(MatchFinder *Finder) {
23  if (!getLangOpts().CPlusPlus11)
24  return;
25 
26  // Swap as a function need not to be considered, because rvalue can not
27  // be bound to a non-const reference.
28  const auto ShrinkableAsMember =
29  memberExpr(member(valueDecl().bind("ContainerDecl")));
30  const auto ShrinkableAsDecl =
31  declRefExpr(hasDeclaration(valueDecl().bind("ContainerDecl")));
32  const auto CopyCtorCall = cxxConstructExpr(hasArgument(
33  0, anyOf(ShrinkableAsMember, ShrinkableAsDecl,
34  unaryOperator(has(ignoringParenImpCasts(ShrinkableAsMember))),
35  unaryOperator(has(ignoringParenImpCasts(ShrinkableAsDecl))))));
36  const auto SwapParam =
37  expr(anyOf(memberExpr(member(equalsBoundNode("ContainerDecl"))),
38  declRefExpr(hasDeclaration(equalsBoundNode("ContainerDecl"))),
39  unaryOperator(has(ignoringParenImpCasts(
40  memberExpr(member(equalsBoundNode("ContainerDecl")))))),
41  unaryOperator(has(ignoringParenImpCasts(declRefExpr(
42  hasDeclaration(equalsBoundNode("ContainerDecl"))))))));
43 
44  Finder->addMatcher(
45  cxxMemberCallExpr(
46  on(hasType(hasCanonicalType(hasDeclaration(namedDecl(
47  hasAnyName("std::basic_string", "std::deque", "std::vector")))))),
48  callee(cxxMethodDecl(hasName("swap"))),
49  has(ignoringParenImpCasts(memberExpr(hasDescendant(CopyCtorCall)))),
50  hasArgument(0, SwapParam.bind("ContainerToShrink")),
51  unless(isInTemplateInstantiation()))
52  .bind("CopyAndSwapTrick"),
53  this);
54 }
55 
56 void ShrinkToFitCheck::check(const MatchFinder::MatchResult &Result) {
57  const auto *MemberCall =
58  Result.Nodes.getNodeAs<CXXMemberCallExpr>("CopyAndSwapTrick");
59  const auto *Container = Result.Nodes.getNodeAs<Expr>("ContainerToShrink");
60  FixItHint Hint;
61 
62  if (!MemberCall->getBeginLoc().isMacroID()) {
63  const LangOptions &Opts = getLangOpts();
64  std::string ReplacementText;
65  if (const auto *UnaryOp = llvm::dyn_cast<UnaryOperator>(Container)) {
66  ReplacementText =
67  Lexer::getSourceText(CharSourceRange::getTokenRange(
68  UnaryOp->getSubExpr()->getSourceRange()),
69  *Result.SourceManager, Opts);
70  ReplacementText += "->shrink_to_fit()";
71  } else {
72  ReplacementText = Lexer::getSourceText(
73  CharSourceRange::getTokenRange(Container->getSourceRange()),
74  *Result.SourceManager, Opts);
75  ReplacementText += ".shrink_to_fit()";
76  }
77 
78  Hint = FixItHint::CreateReplacement(MemberCall->getSourceRange(),
79  ReplacementText);
80  }
81 
82  diag(MemberCall->getBeginLoc(), "the shrink_to_fit method should be used "
83  "to reduce the capacity of a shrinkable "
84  "container")
85  << Hint;
86 }
87 
88 } // namespace modernize
89 } // namespace tidy
90 } // namespace clang
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//