clang-tools 6.0.0

AvoidConstParamsInDecls.cpp
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1 //===--- AvoidConstParamsInDecls.cpp - clang-tidy--------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "AvoidConstParamsInDecls.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/ASTMatchers/ASTMatchers.h"
13 #include "clang/Lex/Lexer.h"
14 #include "llvm/ADT/Optional.h"
15
16 using namespace clang::ast_matchers;
17
18 namespace clang {
19 namespace tidy {
20 namespace readability {
21 namespace {
22
23 SourceRange getTypeRange(const ParmVarDecl &Param) {
24 if (Param.getIdentifier() != nullptr)
25 return SourceRange(Param.getLocStart(),
26 Param.getLocEnd().getLocWithOffset(-1));
27 return Param.getSourceRange();
28 }
29
30 } // namespace
31
32 void AvoidConstParamsInDecls::registerMatchers(MatchFinder *Finder) {
33 const auto ConstParamDecl =
34 parmVarDecl(hasType(qualType(isConstQualified()))).bind("param");
35 Finder->addMatcher(
36 functionDecl(unless(isDefinition()),
37 // Lambdas are always their own definition, but they
38 // generate a non-definition FunctionDecl too. Ignore those.
39 // Class template instantiations have a non-definition
40 // CXXMethodDecl for methods that aren't used in this
41 // translation unit. Ignore those, as the template will have
42 // already been checked.
43 unless(cxxMethodDecl(ofClass(cxxRecordDecl(anyOf(
44 isLambda(), ast_matchers::isTemplateInstantiation()))))),
45 has(typeLoc(forEach(ConstParamDecl))))
46 .bind("func"),
47 this);
48 }
49
50 // Re-lex the tokens to get precise location of last 'const'
51 static llvm::Optional<Token> ConstTok(CharSourceRange Range,
52 const MatchFinder::MatchResult &Result) {
53 const SourceManager &Sources = *Result.SourceManager;
54 std::pair<FileID, unsigned> LocInfo =
55 Sources.getDecomposedLoc(Range.getBegin());
56 StringRef File = Sources.getBufferData(LocInfo.first);
57 const char *TokenBegin = File.data() + LocInfo.second;
58 Lexer RawLexer(Sources.getLocForStartOfFile(LocInfo.first),
59 Result.Context->getLangOpts(), File.begin(), TokenBegin,
60 File.end());
61 Token Tok;
62 llvm::Optional<Token> ConstTok;
63 while (!RawLexer.LexFromRawLexer(Tok)) {
64 if (Sources.isBeforeInTranslationUnit(Range.getEnd(), Tok.getLocation()))
65 break;
66 if (Tok.is(tok::raw_identifier)) {
67 IdentifierInfo &Info = Result.Context->Idents.get(StringRef(
68 Sources.getCharacterData(Tok.getLocation()), Tok.getLength()));
69 Tok.setIdentifierInfo(&Info);
70 Tok.setKind(Info.getTokenID());
71 }
72 if (Tok.is(tok::kw_const))
73 ConstTok = Tok;
74 }
75 return ConstTok;
76 }
77
78 void AvoidConstParamsInDecls::check(const MatchFinder::MatchResult &Result) {
79 const auto *Func = Result.Nodes.getNodeAs<FunctionDecl>("func");
80 const auto *Param = Result.Nodes.getNodeAs<ParmVarDecl>("param");
81
82 if (!Param->getType().isLocalConstQualified())
83 return;
84
85 auto Diag = diag(Param->getLocStart(),
86 "parameter %0 is const-qualified in the function "
87 "declaration; const-qualification of parameters only has an "
88 "effect in function definitions");
89 if (Param->getName().empty()) {
90 for (unsigned int i = 0; i < Func->getNumParams(); ++i) {
91 if (Param == Func->getParamDecl(i)) {
92 Diag << (i + 1);
93 break;
94 }
95 }
96 } else {
97 Diag << Param;
98 }
99
100 if (Param->getLocStart().isMacroID() != Param->getLocEnd().isMacroID()) {
101 // Do not offer a suggestion if the part of the variable declaration comes
102 // from a macro.
103 return;
104 }
105
106 CharSourceRange FileRange = Lexer::makeFileCharRange(
107 CharSourceRange::getTokenRange(getTypeRange(*Param)),
108 *Result.SourceManager, getLangOpts());
109
110 if (!FileRange.isValid())
111 return;
112
113 auto Tok = ConstTok(FileRange, Result);
114 if (!Tok)
115 return;
116 Diag << FixItHint::CreateRemoval(
117 CharSourceRange::getTokenRange(Tok->getLocation(), Tok->getLocation()));
118 }
119
120 } // namespace readability
121 } // namespace tidy
122 } // namespace clang
clang::ast_matchers
Definition: ClangTidyDiagnosticConsumer.h:27
File
HeaderHandle File
Definition: PreprocessorTracker.cpp:526
clang::tidy::readability::ConstTok
static llvm::Optional< Token > ConstTok(CharSourceRange Range, const MatchFinder::MatchResult &Result)
Definition: AvoidConstParamsInDecls.cpp:51
Info
FunctionInfo Info
Definition: FunctionSizeCheck.cpp:84
clang
Definition: AndroidTidyModule.cpp:28
Range
CharSourceRange Range
SourceRange for the file name.
Definition: IncludeOrderCheck.cpp:37
AvoidConstParamsInDecls.h