clang-tools 10.0.0

AvoidConstParamsInDecls.cpp
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1 //===--- AvoidConstParamsInDecls.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 "AvoidConstParamsInDecls.h"
10 #include "clang/ASTMatchers/ASTMatchFinder.h"
11 #include "clang/ASTMatchers/ASTMatchers.h"
12 #include "clang/Lex/Lexer.h"
13 #include "llvm/ADT/Optional.h"
14
15 using namespace clang::ast_matchers;
16
17 namespace clang {
18 namespace tidy {
19 namespace readability {
20 namespace {
21
22 SourceRange getTypeRange(const ParmVarDecl &Param) {
23 if (Param.getIdentifier() != nullptr)
24 return SourceRange(Param.getBeginLoc(),
25 Param.getEndLoc().getLocWithOffset(-1));
26 return Param.getSourceRange();
27 }
28
29 } // namespace
30
31 void AvoidConstParamsInDecls::registerMatchers(MatchFinder *Finder) {
32 const auto ConstParamDecl =
33 parmVarDecl(hasType(qualType(isConstQualified()))).bind("param");
34 Finder->addMatcher(
35 functionDecl(unless(isDefinition()),
36 // Lambdas are always their own definition, but they
37 // generate a non-definition FunctionDecl too. Ignore those.
38 // Class template instantiations have a non-definition
39 // CXXMethodDecl for methods that aren't used in this
40 // translation unit. Ignore those, as the template will have
41 // already been checked.
42 unless(cxxMethodDecl(ofClass(cxxRecordDecl(anyOf(
43 isLambda(), ast_matchers::isTemplateInstantiation()))))),
44 has(typeLoc(forEach(ConstParamDecl))))
45 .bind("func"),
46 this);
47 }
48
49 // Re-lex the tokens to get precise location of last 'const'
50 static llvm::Optional<Token> ConstTok(CharSourceRange Range,
51 const MatchFinder::MatchResult &Result) {
52 const SourceManager &Sources = *Result.SourceManager;
53 std::pair<FileID, unsigned> LocInfo =
54 Sources.getDecomposedLoc(Range.getBegin());
55 StringRef File = Sources.getBufferData(LocInfo.first);
56 const char *TokenBegin = File.data() + LocInfo.second;
57 Lexer RawLexer(Sources.getLocForStartOfFile(LocInfo.first),
58 Result.Context->getLangOpts(), File.begin(), TokenBegin,
59 File.end());
60 Token Tok;
61 llvm::Optional<Token> ConstTok;
62 while (!RawLexer.LexFromRawLexer(Tok)) {
63 if (Sources.isBeforeInTranslationUnit(Range.getEnd(), Tok.getLocation()))
64 break;
65 if (Tok.is(tok::raw_identifier)) {
66 IdentifierInfo &Info = Result.Context->Idents.get(StringRef(
67 Sources.getCharacterData(Tok.getLocation()), Tok.getLength()));
68 Tok.setIdentifierInfo(&Info);
69 Tok.setKind(Info.getTokenID());
70 }
71 if (Tok.is(tok::kw_const))
72 ConstTok = Tok;
73 }
74 return ConstTok;
75 }
76
77 void AvoidConstParamsInDecls::check(const MatchFinder::MatchResult &Result) {
78 const auto *Func = Result.Nodes.getNodeAs<FunctionDecl>("func");
79 const auto *Param = Result.Nodes.getNodeAs<ParmVarDecl>("param");
80
81 if (!Param->getType().isLocalConstQualified())
82 return;
83
84 auto Diag = diag(Param->getBeginLoc(),
85 "parameter %0 is const-qualified in the function "
86 "declaration; const-qualification of parameters only has an "
87 "effect in function definitions");
88 if (Param->getName().empty()) {
89 for (unsigned int i = 0; i < Func->getNumParams(); ++i) {
90 if (Param == Func->getParamDecl(i)) {
91 Diag << (i + 1);
92 break;
93 }
94 }
95 } else {
96 Diag << Param;
97 }
98
99 if (Param->getBeginLoc().isMacroID() != Param->getEndLoc().isMacroID()) {
100 // Do not offer a suggestion if the part of the variable declaration comes
101 // from a macro.
102 return;
103 }
104
105 CharSourceRange FileRange = Lexer::makeFileCharRange(
106 CharSourceRange::getTokenRange(getTypeRange(*Param)),
107 *Result.SourceManager, getLangOpts());
108
109 if (!FileRange.isValid())
110 return;
111
112 auto Tok = ConstTok(FileRange, Result);
113 if (!Tok)
114 return;
115 Diag << FixItHint::CreateRemoval(
116 CharSourceRange::getTokenRange(Tok->getLocation(), Tok->getLocation()));
117 }
118
119 } // namespace readability
120 } // namespace tidy
121 } // namespace clang
clang::ast_matchers
Definition: AbseilMatcher.h:14
clang::tidy::readability::ConstTok
static llvm::Optional< Token > ConstTok(CharSourceRange Range, const MatchFinder::MatchResult &Result)
Definition: AvoidConstParamsInDecls.cpp:50
clang::clangd::getTokenRange
llvm::Optional< Range > getTokenRange(const SourceManager &SM, const LangOptions &LangOpts, SourceLocation TokLoc)
Returns the taken range at TokLoc.
Definition: SourceCode.cpp:227
Info
FunctionInfo Info
Definition: FunctionSizeCheck.cpp:120
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
Range
CharSourceRange Range
SourceRange for the file name.
Definition: IncludeOrderCheck.cpp:38
AvoidConstParamsInDecls.h