clang-tools  10.0.0git
InitVariablesCheck.cpp
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1 //===--- InitVariablesCheck.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 "InitVariablesCheck.h"
10 
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 cppcoreguidelines {
19 
20 namespace {
21 AST_MATCHER(VarDecl, isLocalVarDecl) { return Node.isLocalVarDecl(); }
22 } // namespace
23 
24 InitVariablesCheck::InitVariablesCheck(StringRef Name,
25  ClangTidyContext *Context)
26  : ClangTidyCheck(Name, Context),
27  IncludeStyle(utils::IncludeSorter::parseIncludeStyle(
28  Options.getLocalOrGlobal("IncludeStyle", "llvm"))),
29  MathHeader(Options.get("MathHeader", "math.h")) {}
30 
31 void InitVariablesCheck::registerMatchers(MatchFinder *Finder) {
32  Finder->addMatcher(varDecl(unless(hasInitializer(anything())),
33  unless(isInstantiated()), isLocalVarDecl(),
34  unless(isStaticLocal()), isDefinition())
35  .bind("vardecl"),
36  this);
37 }
38 
39 void InitVariablesCheck::registerPPCallbacks(const SourceManager &SM,
40  Preprocessor *PP,
41  Preprocessor *ModuleExpanderPP) {
42  IncludeInserter =
43  std::make_unique<utils::IncludeInserter>(SM, getLangOpts(), IncludeStyle);
44  PP->addPPCallbacks(IncludeInserter->CreatePPCallbacks());
45 }
46 
47 void InitVariablesCheck::check(const MatchFinder::MatchResult &Result) {
48  const auto *MatchedDecl = Result.Nodes.getNodeAs<VarDecl>("vardecl");
49  const ASTContext &Context = *Result.Context;
50  const SourceManager &Source = Context.getSourceManager();
51 
52  // We want to warn about cases where the type name
53  // comes from a macro like this:
54  //
55  // TYPENAME_FROM_MACRO var;
56  //
57  // but not if the entire declaration comes from
58  // one:
59  //
60  // DEFINE_SOME_VARIABLE();
61  //
62  // or if the definition comes from a macro like SWAP
63  // that uses an internal temporary variable.
64  //
65  // Thus check that the variable name does
66  // not come from a macro expansion.
67  if (MatchedDecl->getEndLoc().isMacroID())
68  return;
69 
70  QualType TypePtr = MatchedDecl->getType();
71  const char *InitializationString = nullptr;
72  bool AddMathInclude = false;
73 
74  if (TypePtr->isIntegerType())
75  InitializationString = " = 0";
76  else if (TypePtr->isFloatingType()) {
77  InitializationString = " = NAN";
78  AddMathInclude = true;
79  } else if (TypePtr->isAnyPointerType()) {
80  if (getLangOpts().CPlusPlus11)
81  InitializationString = " = nullptr";
82  else
83  InitializationString = " = NULL";
84  }
85 
86  if (InitializationString) {
87  auto Diagnostic =
88  diag(MatchedDecl->getLocation(), "variable %0 is not initialized")
89  << MatchedDecl
90  << FixItHint::CreateInsertion(
91  MatchedDecl->getLocation().getLocWithOffset(
92  MatchedDecl->getName().size()),
93  InitializationString);
94  if (AddMathInclude) {
95  auto IncludeHint = IncludeInserter->CreateIncludeInsertion(
96  Source.getFileID(MatchedDecl->getBeginLoc()), MathHeader, false);
97  if (IncludeHint)
98  Diagnostic << *IncludeHint;
99  }
100  }
101 }
102 
103 } // namespace cppcoreguidelines
104 } // namespace tidy
105 } // namespace clang
Base class for all clang-tidy checks.
const LangOptions & getLangOpts() const
Returns the language options from the context.
static constexpr llvm::StringLiteral Name
void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) override
Override this to register PPCallbacks in the preprocessor.
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
===– 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.