clang-tools  9.0.0
ShrinkToFitCheck.cpp
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1 //===--- ShrinkToFitCheck.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 "ShrinkToFitCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/Lex/Lexer.h"
13 #include "llvm/ADT/StringRef.h"
14 
15 using namespace clang::ast_matchers;
16 
17 namespace clang {
18 namespace tidy {
19 namespace modernize {
20 
21 void ShrinkToFitCheck::registerMatchers(MatchFinder *Finder) {
22  if (!getLangOpts().CPlusPlus11)
23  return;
24 
25  // Swap as a function need not to be considered, because rvalue can not
26  // be bound to a non-const reference.
27  const auto ShrinkableAsMember =
28  memberExpr(member(valueDecl().bind("ContainerDecl")));
29  const auto ShrinkableAsDecl =
30  declRefExpr(hasDeclaration(valueDecl().bind("ContainerDecl")));
31  const auto CopyCtorCall = cxxConstructExpr(hasArgument(
32  0, anyOf(ShrinkableAsMember, ShrinkableAsDecl,
33  unaryOperator(has(ignoringParenImpCasts(ShrinkableAsMember))),
34  unaryOperator(has(ignoringParenImpCasts(ShrinkableAsDecl))))));
35  const auto SwapParam =
36  expr(anyOf(memberExpr(member(equalsBoundNode("ContainerDecl"))),
37  declRefExpr(hasDeclaration(equalsBoundNode("ContainerDecl"))),
38  unaryOperator(has(ignoringParenImpCasts(
39  memberExpr(member(equalsBoundNode("ContainerDecl")))))),
40  unaryOperator(has(ignoringParenImpCasts(declRefExpr(
41  hasDeclaration(equalsBoundNode("ContainerDecl"))))))));
42 
43  Finder->addMatcher(
44  cxxMemberCallExpr(
45  on(hasType(hasCanonicalType(hasDeclaration(namedDecl(
46  hasAnyName("std::basic_string", "std::deque", "std::vector")))))),
47  callee(cxxMethodDecl(hasName("swap"))),
48  has(ignoringParenImpCasts(memberExpr(hasDescendant(CopyCtorCall)))),
49  hasArgument(0, SwapParam.bind("ContainerToShrink")),
50  unless(isInTemplateInstantiation()))
51  .bind("CopyAndSwapTrick"),
52  this);
53 }
54 
55 void ShrinkToFitCheck::check(const MatchFinder::MatchResult &Result) {
56  const auto *MemberCall =
57  Result.Nodes.getNodeAs<CXXMemberCallExpr>("CopyAndSwapTrick");
58  const auto *Container = Result.Nodes.getNodeAs<Expr>("ContainerToShrink");
59  FixItHint Hint;
60 
61  if (!MemberCall->getBeginLoc().isMacroID()) {
62  const LangOptions &Opts = getLangOpts();
63  std::string ReplacementText;
64  if (const auto *UnaryOp = llvm::dyn_cast<UnaryOperator>(Container)) {
65  ReplacementText =
66  Lexer::getSourceText(CharSourceRange::getTokenRange(
67  UnaryOp->getSubExpr()->getSourceRange()),
68  *Result.SourceManager, Opts);
69  ReplacementText += "->shrink_to_fit()";
70  } else {
71  ReplacementText = Lexer::getSourceText(
72  CharSourceRange::getTokenRange(Container->getSourceRange()),
73  *Result.SourceManager, Opts);
74  ReplacementText += ".shrink_to_fit()";
75  }
76 
77  Hint = FixItHint::CreateReplacement(MemberCall->getSourceRange(),
78  ReplacementText);
79  }
80 
81  diag(MemberCall->getBeginLoc(), "the shrink_to_fit method should be used "
82  "to reduce the capacity of a shrinkable "
83  "container")
84  << Hint;
85 }
86 
87 } // namespace modernize
88 } // namespace tidy
89 } // namespace clang
llvm::Optional< Range > getTokenRange(const SourceManager &SM, const LangOptions &LangOpts, SourceLocation TokLoc)
Returns the taken range at TokLoc.
Definition: SourceCode.cpp:203
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
Definition: Rename.cpp:36