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| //===--- AvoidConstParamsInDecls.cpp - clang-tidy--------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "AvoidConstParamsInDecls.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/Optional.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace readability {
namespace {
SourceRange getTypeRange(const ParmVarDecl &Param) {
if (Param.getIdentifier() != nullptr)
return SourceRange(Param.getBeginLoc(),
Param.getEndLoc().getLocWithOffset(-1));
return Param.getSourceRange();
}
} // namespace
void AvoidConstParamsInDecls::registerMatchers(MatchFinder *Finder) {
const auto ConstParamDecl =
parmVarDecl(hasType(qualType(isConstQualified()))).bind("param");
Finder->addMatcher(
functionDecl(unless(isDefinition()),
// Lambdas are always their own definition, but they
// generate a non-definition FunctionDecl too. Ignore those.
// Class template instantiations have a non-definition
// CXXMethodDecl for methods that aren't used in this
// translation unit. Ignore those, as the template will have
// already been checked.
unless(cxxMethodDecl(ofClass(cxxRecordDecl(anyOf(
isLambda(), ast_matchers::isTemplateInstantiation()))))),
has(typeLoc(forEach(ConstParamDecl))))
.bind("func"),
this);
}
// Re-lex the tokens to get precise location of last 'const'
static llvm::Optional<Token> ConstTok(CharSourceRange Range,
const MatchFinder::MatchResult &Result) {
const SourceManager &Sources = *Result.SourceManager;
std::pair<FileID, unsigned> LocInfo =
Sources.getDecomposedLoc(Range.getBegin());
StringRef File = Sources.getBufferData(LocInfo.first);
const char *TokenBegin = File.data() + LocInfo.second;
Lexer RawLexer(Sources.getLocForStartOfFile(LocInfo.first),
Result.Context->getLangOpts(), File.begin(), TokenBegin,
File.end());
Token Tok;
llvm::Optional<Token> ConstTok;
while (!RawLexer.LexFromRawLexer(Tok)) {
if (Sources.isBeforeInTranslationUnit(Range.getEnd(), Tok.getLocation()))
break;
if (Tok.is(tok::raw_identifier)) {
IdentifierInfo &Info = Result.Context->Idents.get(StringRef(
Sources.getCharacterData(Tok.getLocation()), Tok.getLength()));
Tok.setIdentifierInfo(&Info);
Tok.setKind(Info.getTokenID());
}
if (Tok.is(tok::kw_const))
ConstTok = Tok;
}
return ConstTok;
}
void AvoidConstParamsInDecls::check(const MatchFinder::MatchResult &Result) {
const auto *Func = Result.Nodes.getNodeAs<FunctionDecl>("func");
const auto *Param = Result.Nodes.getNodeAs<ParmVarDecl>("param");
if (!Param->getType().isLocalConstQualified())
return;
auto Diag = diag(Param->getBeginLoc(),
"parameter %0 is const-qualified in the function "
"declaration; const-qualification of parameters only has an "
"effect in function definitions");
if (Param->getName().empty()) {
for (unsigned int i = 0; i < Func->getNumParams(); ++i) {
if (Param == Func->getParamDecl(i)) {
Diag << (i + 1);
break;
}
}
} else {
Diag << Param;
}
if (Param->getBeginLoc().isMacroID() != Param->getEndLoc().isMacroID()) {
// Do not offer a suggestion if the part of the variable declaration comes
// from a macro.
return;
}
CharSourceRange FileRange = Lexer::makeFileCharRange(
CharSourceRange::getTokenRange(getTypeRange(*Param)),
*Result.SourceManager, getLangOpts());
if (!FileRange.isValid())
return;
auto Tok = ConstTok(FileRange, Result);
if (!Tok)
return;
Diag << FixItHint::CreateRemoval(
CharSourceRange::getTokenRange(Tok->getLocation(), Tok->getLocation()));
}
} // namespace readability
} // namespace tidy
} // namespace clang
|