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 MathHeader(Options.get("MathHeader", "<math.h>")) {}
32
storeOptions(ClangTidyOptions::OptionMap & Opts)33 void InitVariablesCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
34 Options.store(Opts, "IncludeStyle", IncludeInserter.getStyle());
35 Options.store(Opts, "MathHeader", MathHeader);
36 }
37
registerMatchers(MatchFinder * Finder)38 void InitVariablesCheck::registerMatchers(MatchFinder *Finder) {
39 std::string BadDecl = "badDecl";
40 Finder->addMatcher(
41 varDecl(unless(hasInitializer(anything())), unless(isInstantiated()),
42 isLocalVarDecl(), unless(isStaticLocal()), isDefinition(),
43 unless(hasParent(cxxCatchStmt())),
44 optionally(hasParent(declStmt(hasParent(
45 cxxForRangeStmt(hasLoopVariable(varDecl().bind(BadDecl))))))),
46 unless(equalsBoundNode(BadDecl)))
47 .bind("vardecl"),
48 this);
49 }
50
registerPPCallbacks(const SourceManager & SM,Preprocessor * PP,Preprocessor * ModuleExpanderPP)51 void InitVariablesCheck::registerPPCallbacks(const SourceManager &SM,
52 Preprocessor *PP,
53 Preprocessor *ModuleExpanderPP) {
54 IncludeInserter.registerPreprocessor(PP);
55 }
56
check(const MatchFinder::MatchResult & Result)57 void InitVariablesCheck::check(const MatchFinder::MatchResult &Result) {
58 const auto *MatchedDecl = Result.Nodes.getNodeAs<VarDecl>("vardecl");
59 const ASTContext &Context = *Result.Context;
60 const SourceManager &Source = Context.getSourceManager();
61
62 // We want to warn about cases where the type name
63 // comes from a macro like this:
64 //
65 // TYPENAME_FROM_MACRO var;
66 //
67 // but not if the entire declaration comes from
68 // one:
69 //
70 // DEFINE_SOME_VARIABLE();
71 //
72 // or if the definition comes from a macro like SWAP
73 // that uses an internal temporary variable.
74 //
75 // Thus check that the variable name does
76 // not come from a macro expansion.
77 if (MatchedDecl->getEndLoc().isMacroID())
78 return;
79
80 QualType TypePtr = MatchedDecl->getType();
81 const char *InitializationString = nullptr;
82 bool AddMathInclude = false;
83
84 if (TypePtr->isIntegerType())
85 InitializationString = " = 0";
86 else if (TypePtr->isFloatingType()) {
87 InitializationString = " = NAN";
88 AddMathInclude = true;
89 } else if (TypePtr->isAnyPointerType()) {
90 if (getLangOpts().CPlusPlus11)
91 InitializationString = " = nullptr";
92 else
93 InitializationString = " = NULL";
94 }
95
96 if (InitializationString) {
97 auto Diagnostic =
98 diag(MatchedDecl->getLocation(), "variable %0 is not initialized")
99 << MatchedDecl
100 << FixItHint::CreateInsertion(
101 MatchedDecl->getLocation().getLocWithOffset(
102 MatchedDecl->getName().size()),
103 InitializationString);
104 if (AddMathInclude) {
105 Diagnostic << IncludeInserter.createIncludeInsertion(
106 Source.getFileID(MatchedDecl->getBeginLoc()), MathHeader);
107 }
108 }
109 }
110 } // namespace cppcoreguidelines
111 } // namespace tidy
112 } // namespace clang
113