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//===--- UseOverrideCheck.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 "UseOverrideCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Lex/Lexer.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace modernize {
UseOverrideCheck::UseOverrideCheck(StringRef Name, ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
IgnoreDestructors(Options.get("IgnoreDestructors", false)),
AllowOverrideAndFinal(Options.get("AllowOverrideAndFinal", false)),
OverrideSpelling(Options.get("OverrideSpelling", "override")),
FinalSpelling(Options.get("FinalSpelling", "final")) {}
void UseOverrideCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "IgnoreDestructors", IgnoreDestructors);
Options.store(Opts, "AllowOverrideAndFinal", AllowOverrideAndFinal);
Options.store(Opts, "OverrideSpelling", OverrideSpelling);
Options.store(Opts, "FinalSpelling", FinalSpelling);
}
void UseOverrideCheck::registerMatchers(MatchFinder *Finder) {
if (IgnoreDestructors)
Finder->addMatcher(
cxxMethodDecl(isOverride(), unless(cxxDestructorDecl())).bind("method"),
this);
else
Finder->addMatcher(cxxMethodDecl(isOverride()).bind("method"), this);
}
// Re-lex the tokens to get precise locations to insert 'override' and remove
// 'virtual'.
static SmallVector<Token, 16>
parseTokens(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());
SmallVector<Token, 16> Tokens;
Token Tok;
int NestedParens = 0;
while (!RawLexer.LexFromRawLexer(Tok)) {
if ((Tok.is(tok::semi) || Tok.is(tok::l_brace)) && NestedParens == 0)
break;
if (Sources.isBeforeInTranslationUnit(Range.getEnd(), Tok.getLocation()))
break;
if (Tok.is(tok::l_paren))
++NestedParens;
else if (Tok.is(tok::r_paren))
--NestedParens;
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());
}
Tokens.push_back(Tok);
}
return Tokens;
}
static StringRef getText(const Token &Tok, const SourceManager &Sources) {
return StringRef(Sources.getCharacterData(Tok.getLocation()),
Tok.getLength());
}
void UseOverrideCheck::check(const MatchFinder::MatchResult &Result) {
const auto *Method = Result.Nodes.getNodeAs<FunctionDecl>("method");
const SourceManager &Sources = *Result.SourceManager;
ASTContext &Context = *Result.Context;
assert(Method != nullptr);
if (Method->getInstantiatedFromMemberFunction() != nullptr)
Method = Method->getInstantiatedFromMemberFunction();
if (Method->isImplicit() || Method->getLocation().isMacroID() ||
Method->isOutOfLine())
return;
bool HasVirtual = Method->isVirtualAsWritten();
bool HasOverride = Method->getAttr<OverrideAttr>();
bool HasFinal = Method->getAttr<FinalAttr>();
bool OnlyVirtualSpecified = HasVirtual && !HasOverride && !HasFinal;
unsigned KeywordCount = HasVirtual + HasOverride + HasFinal;
if ((!OnlyVirtualSpecified && KeywordCount == 1) ||
(!HasVirtual && HasOverride && HasFinal && AllowOverrideAndFinal))
return; // Nothing to do.
std::string Message;
if (OnlyVirtualSpecified) {
Message = "prefer using '%0' or (rarely) '%1' instead of 'virtual'";
} else if (KeywordCount == 0) {
Message = "annotate this function with '%0' or (rarely) '%1'";
} else {
StringRef Redundant =
HasVirtual ? (HasOverride && HasFinal && !AllowOverrideAndFinal
? "'virtual' and '%0' are"
: "'virtual' is")
: "'%0' is";
StringRef Correct = HasFinal ? "'%1'" : "'%0'";
Message = (llvm::Twine(Redundant) +
" redundant since the function is already declared " + Correct)
.str();
}
auto Diag = diag(Method->getLocation(), Message)
<< OverrideSpelling << FinalSpelling;
CharSourceRange FileRange = Lexer::makeFileCharRange(
CharSourceRange::getTokenRange(Method->getSourceRange()), Sources,
getLangOpts());
if (!FileRange.isValid())
return;
// FIXME: Instead of re-lexing and looking for specific macros such as
// 'ABSTRACT', properly store the location of 'virtual' and '= 0' in each
// FunctionDecl.
SmallVector<Token, 16> Tokens = parseTokens(FileRange, Result);
// Add 'override' on inline declarations that don't already have it.
if (!HasFinal && !HasOverride) {
SourceLocation InsertLoc;
std::string ReplacementText = OverrideSpelling + " ";
SourceLocation MethodLoc = Method->getLocation();
for (Token T : Tokens) {
if (T.is(tok::kw___attribute) &&
!Sources.isBeforeInTranslationUnit(T.getLocation(), MethodLoc)) {
InsertLoc = T.getLocation();
break;
}
}
if (Method->hasAttrs()) {
for (const clang::Attr *A : Method->getAttrs()) {
if (!A->isImplicit() && !A->isInherited()) {
SourceLocation Loc =
Sources.getExpansionLoc(A->getRange().getBegin());
if ((!InsertLoc.isValid() ||
Sources.isBeforeInTranslationUnit(Loc, InsertLoc)) &&
!Sources.isBeforeInTranslationUnit(Loc, MethodLoc))
InsertLoc = Loc;
}
}
}
if (InsertLoc.isInvalid() && Method->doesThisDeclarationHaveABody() &&
Method->getBody() && !Method->isDefaulted()) {
// For methods with inline definition, add the override keyword at the
// end of the declaration of the function, but prefer to put it on the
// same line as the declaration if the beginning brace for the start of
// the body falls on the next line.
ReplacementText = " " + OverrideSpelling;
auto *LastTokenIter = std::prev(Tokens.end());
// When try statement is used instead of compound statement as
// method body - insert override keyword before it.
if (LastTokenIter->is(tok::kw_try))
LastTokenIter = std::prev(LastTokenIter);
InsertLoc = LastTokenIter->getEndLoc();
}
if (!InsertLoc.isValid()) {
// For declarations marked with "= 0" or "= [default|delete]", the end
// location will point until after those markings. Therefore, the override
// keyword shouldn't be inserted at the end, but before the '='.
if (Tokens.size() > 2 &&
(getText(Tokens.back(), Sources) == "0" ||
Tokens.back().is(tok::kw_default) ||
Tokens.back().is(tok::kw_delete)) &&
getText(Tokens[Tokens.size() - 2], Sources) == "=") {
InsertLoc = Tokens[Tokens.size() - 2].getLocation();
// Check if we need to insert a space.
if ((Tokens[Tokens.size() - 2].getFlags() & Token::LeadingSpace) == 0)
ReplacementText = " " + OverrideSpelling + " ";
} else if (getText(Tokens.back(), Sources) == "ABSTRACT")
InsertLoc = Tokens.back().getLocation();
}
if (!InsertLoc.isValid()) {
InsertLoc = FileRange.getEnd();
ReplacementText = " " + OverrideSpelling;
}
// If the override macro has been specified just ensure it exists,
// if not don't apply a fixit but keep the warning.
if (OverrideSpelling != "override" &&
!Context.Idents.get(OverrideSpelling).hasMacroDefinition())
return;
Diag << FixItHint::CreateInsertion(InsertLoc, ReplacementText);
}
if (HasFinal && HasOverride && !AllowOverrideAndFinal) {
SourceLocation OverrideLoc = Method->getAttr<OverrideAttr>()->getLocation();
Diag << FixItHint::CreateRemoval(
CharSourceRange::getTokenRange(OverrideLoc, OverrideLoc));
}
if (HasVirtual) {
for (Token Tok : Tokens) {
if (Tok.is(tok::kw_virtual)) {
Diag << FixItHint::CreateRemoval(CharSourceRange::getTokenRange(
Tok.getLocation(), Tok.getLocation()));
break;
}
}
}
}
} // namespace modernize
} // namespace tidy
} // namespace clang
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