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 #include "clang/Lex/PPCallbacks.h"
14 #include "clang/Lex/Preprocessor.h"
15
16 using namespace clang::ast_matchers;
17
18 namespace clang {
19 namespace tidy {
20 namespace cppcoreguidelines {
21
22 namespace {
AST_MATCHER(VarDecl,isLocalVarDecl)23 AST_MATCHER(VarDecl, isLocalVarDecl) { return Node.isLocalVarDecl(); }
24 } // namespace
25
InitVariablesCheck(StringRef Name,ClangTidyContext * Context)26 InitVariablesCheck::InitVariablesCheck(StringRef Name,
27 ClangTidyContext *Context)
28 : ClangTidyCheck(Name, Context),
29 IncludeInserter(Options.getLocalOrGlobal("IncludeStyle",
30 utils::IncludeSorter::IS_LLVM),
31 areDiagsSelfContained()),
32 MathHeader(Options.get("MathHeader", "<math.h>")) {}
33
storeOptions(ClangTidyOptions::OptionMap & Opts)34 void InitVariablesCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
35 Options.store(Opts, "IncludeStyle", IncludeInserter.getStyle());
36 Options.store(Opts, "MathHeader", MathHeader);
37 }
38
registerMatchers(MatchFinder * Finder)39 void InitVariablesCheck::registerMatchers(MatchFinder *Finder) {
40 std::string BadDecl = "badDecl";
41 Finder->addMatcher(
42 varDecl(unless(hasInitializer(anything())), unless(isInstantiated()),
43 isLocalVarDecl(), unless(isStaticLocal()), isDefinition(),
44 unless(hasParent(cxxCatchStmt())),
45 optionally(hasParent(declStmt(hasParent(
46 cxxForRangeStmt(hasLoopVariable(varDecl().bind(BadDecl))))))),
47 unless(equalsBoundNode(BadDecl)))
48 .bind("vardecl"),
49 this);
50 }
51
registerPPCallbacks(const SourceManager & SM,Preprocessor * PP,Preprocessor * ModuleExpanderPP)52 void InitVariablesCheck::registerPPCallbacks(const SourceManager &SM,
53 Preprocessor *PP,
54 Preprocessor *ModuleExpanderPP) {
55 IncludeInserter.registerPreprocessor(PP);
56 }
57
check(const MatchFinder::MatchResult & Result)58 void InitVariablesCheck::check(const MatchFinder::MatchResult &Result) {
59 const auto *MatchedDecl = Result.Nodes.getNodeAs<VarDecl>("vardecl");
60 const ASTContext &Context = *Result.Context;
61 const SourceManager &Source = Context.getSourceManager();
62
63 // We want to warn about cases where the type name
64 // comes from a macro like this:
65 //
66 // TYPENAME_FROM_MACRO var;
67 //
68 // but not if the entire declaration comes from
69 // one:
70 //
71 // DEFINE_SOME_VARIABLE();
72 //
73 // or if the definition comes from a macro like SWAP
74 // that uses an internal temporary variable.
75 //
76 // Thus check that the variable name does
77 // not come from a macro expansion.
78 if (MatchedDecl->getEndLoc().isMacroID())
79 return;
80
81 QualType TypePtr = MatchedDecl->getType();
82 llvm::Optional<const char *> InitializationString = llvm::None;
83 bool AddMathInclude = false;
84
85 if (TypePtr->isEnumeralType())
86 InitializationString = nullptr;
87 else if (TypePtr->isBooleanType())
88 InitializationString = " = false";
89 else if (TypePtr->isIntegerType())
90 InitializationString = " = 0";
91 else if (TypePtr->isFloatingType()) {
92 InitializationString = " = NAN";
93 AddMathInclude = true;
94 } else if (TypePtr->isAnyPointerType()) {
95 if (getLangOpts().CPlusPlus11)
96 InitializationString = " = nullptr";
97 else
98 InitializationString = " = NULL";
99 }
100
101 if (InitializationString) {
102 auto Diagnostic =
103 diag(MatchedDecl->getLocation(), "variable %0 is not initialized")
104 << MatchedDecl;
105 if (*InitializationString != nullptr)
106 Diagnostic << FixItHint::CreateInsertion(
107 MatchedDecl->getLocation().getLocWithOffset(
108 MatchedDecl->getName().size()),
109 *InitializationString);
110 if (AddMathInclude) {
111 Diagnostic << IncludeInserter.createIncludeInsertion(
112 Source.getFileID(MatchedDecl->getBeginLoc()), MathHeader);
113 }
114 }
115 }
116 } // namespace cppcoreguidelines
117 } // namespace tidy
118 } // namespace clang
119