clang-tools  10.0.0git
UseTransparentFunctorsCheck.cpp
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1 //===--- UseTransparentFunctorsCheck.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 
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 
13 using namespace clang::ast_matchers;
14 
15 namespace clang {
16 namespace tidy {
17 namespace modernize {
18 
19 UseTransparentFunctorsCheck::UseTransparentFunctorsCheck(
20  StringRef Name, ClangTidyContext *Context)
21  : ClangTidyCheck(Name, Context), SafeMode(Options.get("SafeMode", 0)) {}
22 
25  Options.store(Opts, "SafeMode", SafeMode ? 1 : 0);
26 }
27 
29  if (!getLangOpts().CPlusPlus14)
30  return;
31 
32  const auto TransparentFunctors =
33  classTemplateSpecializationDecl(
34  unless(hasAnyTemplateArgument(refersToType(voidType()))),
35  hasAnyName("::std::plus", "::std::minus", "::std::multiplies",
36  "::std::divides", "::std::modulus", "::std::negate",
37  "::std::equal_to", "::std::not_equal_to", "::std::greater",
38  "::std::less", "::std::greater_equal", "::std::less_equal",
39  "::std::logical_and", "::std::logical_or",
40  "::std::logical_not", "::std::bit_and", "::std::bit_or",
41  "::std::bit_xor", "::std::bit_not"))
42  .bind("FunctorClass");
43 
44  // Non-transparent functor mentioned as a template parameter. FIXIT.
45  Finder->addMatcher(
46  loc(qualType(
47  unless(elaboratedType()),
48  hasDeclaration(classTemplateSpecializationDecl(
49  unless(hasAnyTemplateArgument(templateArgument(refersToType(
50  qualType(pointsTo(qualType(isAnyCharacter()))))))),
51  hasAnyTemplateArgument(
52  templateArgument(refersToType(qualType(hasDeclaration(
53  TransparentFunctors))))
54  .bind("Functor"))))))
55  .bind("FunctorParentLoc"),
56  this);
57 
58  if (SafeMode)
59  return;
60 
61  // Non-transparent functor constructed. No FIXIT. There is no easy way
62  // to rule out the problematic char* vs string case.
63  Finder->addMatcher(cxxConstructExpr(hasDeclaration(cxxMethodDecl(
64  ofClass(TransparentFunctors))),
65  unless(isInTemplateInstantiation()))
66  .bind("FuncInst"),
67  this);
68 }
69 
70 static const StringRef Message = "prefer transparent functors '%0'";
71 
72 template <typename T> static T getInnerTypeLocAs(TypeLoc Loc) {
73  T Result;
74  while (Result.isNull() && !Loc.isNull()) {
75  Result = Loc.getAs<T>();
76  Loc = Loc.getNextTypeLoc();
77  }
78  return Result;
79 }
80 
82  const MatchFinder::MatchResult &Result) {
83  const auto *FuncClass =
84  Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>("FunctorClass");
85  if (const auto *FuncInst =
86  Result.Nodes.getNodeAs<CXXConstructExpr>("FuncInst")) {
87  diag(FuncInst->getBeginLoc(), Message)
88  << (FuncClass->getName() + "<>").str();
89  return;
90  }
91 
92  const auto *Functor = Result.Nodes.getNodeAs<TemplateArgument>("Functor");
93  const auto FunctorParentLoc =
94  Result.Nodes.getNodeAs<TypeLoc>("FunctorParentLoc")
95  ->getAs<TemplateSpecializationTypeLoc>();
96 
97  if (!FunctorParentLoc)
98  return;
99 
100  unsigned ArgNum = 0;
101  const auto *FunctorParentType =
102  FunctorParentLoc.getType()->castAs<TemplateSpecializationType>();
103  for (; ArgNum < FunctorParentType->getNumArgs(); ++ArgNum) {
104  const TemplateArgument &Arg = FunctorParentType->getArg(ArgNum);
105  if (Arg.getKind() != TemplateArgument::Type)
106  continue;
107  QualType ParentArgType = Arg.getAsType();
108  if (ParentArgType->isRecordType() &&
109  ParentArgType->getAsCXXRecordDecl() ==
110  Functor->getAsType()->getAsCXXRecordDecl())
111  break;
112  }
113  // Functor is a default template argument.
114  if (ArgNum == FunctorParentType->getNumArgs())
115  return;
116  TemplateArgumentLoc FunctorLoc = FunctorParentLoc.getArgLoc(ArgNum);
117  auto FunctorTypeLoc = getInnerTypeLocAs<TemplateSpecializationTypeLoc>(
118  FunctorLoc.getTypeSourceInfo()->getTypeLoc());
119  if (FunctorTypeLoc.isNull())
120  return;
121 
122  SourceLocation ReportLoc = FunctorLoc.getLocation();
123  if (ReportLoc.isInvalid())
124  return;
125  diag(ReportLoc, Message) << (FuncClass->getName() + "<>").str()
126  << FixItHint::CreateRemoval(
127  FunctorTypeLoc.getArgLoc(0).getSourceRange());
128 }
129 
130 } // namespace modernize
131 } // namespace tidy
132 } // namespace clang
SourceLocation Loc
&#39;#&#39; location in the include directive
static T getInnerTypeLocAs(TypeLoc Loc)
constexpr llvm::StringLiteral Message
Base class for all clang-tidy checks.
const LangOptions & getLangOpts() const
Returns the language options from the context.
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
void store(ClangTidyOptions::OptionMap &Options, StringRef LocalName, StringRef Value) const
Stores an option with the check-local name LocalName with string value Value to Options.
static constexpr llvm::StringLiteral Name
std::map< std::string, std::string > OptionMap
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
void storeOptions(ClangTidyOptions::OptionMap &Opts) override
Should store all options supported by this check with their current values or default values for opti...
NodeType Type
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check&#39;s name.