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 {
AST_MATCHER(VarDecl,isLocalVarDecl)21 AST_MATCHER(VarDecl, isLocalVarDecl) { return Node.isLocalVarDecl(); }
22 } // namespace
23
InitVariablesCheck(StringRef Name,ClangTidyContext * Context)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
registerMatchers(MatchFinder * Finder)31 void InitVariablesCheck::registerMatchers(MatchFinder *Finder) {
32 std::string BadDecl = "badDecl";
33 Finder->addMatcher(
34 varDecl(unless(hasInitializer(anything())), unless(isInstantiated()),
35 isLocalVarDecl(), unless(isStaticLocal()), isDefinition(),
36 optionally(hasParent(declStmt(hasParent(
37 cxxForRangeStmt(hasLoopVariable(varDecl().bind(BadDecl))))))),
38 unless(equalsBoundNode(BadDecl)))
39 .bind("vardecl"),
40 this);
41 }
42
registerPPCallbacks(const SourceManager & SM,Preprocessor * PP,Preprocessor * ModuleExpanderPP)43 void InitVariablesCheck::registerPPCallbacks(const SourceManager &SM,
44 Preprocessor *PP,
45 Preprocessor *ModuleExpanderPP) {
46 IncludeInserter =
47 std::make_unique<utils::IncludeInserter>(SM, getLangOpts(), IncludeStyle);
48 PP->addPPCallbacks(IncludeInserter->CreatePPCallbacks());
49 }
50
check(const MatchFinder::MatchResult & Result)51 void InitVariablesCheck::check(const MatchFinder::MatchResult &Result) {
52 const auto *MatchedDecl = Result.Nodes.getNodeAs<VarDecl>("vardecl");
53 const ASTContext &Context = *Result.Context;
54 const SourceManager &Source = Context.getSourceManager();
55
56 // We want to warn about cases where the type name
57 // comes from a macro like this:
58 //
59 // TYPENAME_FROM_MACRO var;
60 //
61 // but not if the entire declaration comes from
62 // one:
63 //
64 // DEFINE_SOME_VARIABLE();
65 //
66 // or if the definition comes from a macro like SWAP
67 // that uses an internal temporary variable.
68 //
69 // Thus check that the variable name does
70 // not come from a macro expansion.
71 if (MatchedDecl->getEndLoc().isMacroID())
72 return;
73
74 QualType TypePtr = MatchedDecl->getType();
75 const char *InitializationString = nullptr;
76 bool AddMathInclude = false;
77
78 if (TypePtr->isIntegerType())
79 InitializationString = " = 0";
80 else if (TypePtr->isFloatingType()) {
81 InitializationString = " = NAN";
82 AddMathInclude = true;
83 } else if (TypePtr->isAnyPointerType()) {
84 if (getLangOpts().CPlusPlus11)
85 InitializationString = " = nullptr";
86 else
87 InitializationString = " = NULL";
88 }
89
90 if (InitializationString) {
91 auto Diagnostic =
92 diag(MatchedDecl->getLocation(), "variable %0 is not initialized")
93 << MatchedDecl
94 << FixItHint::CreateInsertion(
95 MatchedDecl->getLocation().getLocWithOffset(
96 MatchedDecl->getName().size()),
97 InitializationString);
98 if (AddMathInclude) {
99 auto IncludeHint = IncludeInserter->CreateIncludeInsertion(
100 Source.getFileID(MatchedDecl->getBeginLoc()), MathHeader, false);
101 if (IncludeHint)
102 Diagnostic << *IncludeHint;
103 }
104 }
105 }
106
107 } // namespace cppcoreguidelines
108 } // namespace tidy
109 } // namespace clang
110