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//===--- UseInternalLinkageCheck.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 "UseInternalLinkageCheck.h"
#include "../utils/FileExtensionsUtils.h"
#include "clang/AST/Decl.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/ASTMatchers/ASTMatchersMacros.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/Specifiers.h"
#include "clang/Lex/Token.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
using namespace clang::ast_matchers;
namespace clang::tidy {
template <>
struct OptionEnumMapping<misc::UseInternalLinkageCheck::FixModeKind> {
static llvm::ArrayRef<
std::pair<misc::UseInternalLinkageCheck::FixModeKind, StringRef>>
getEnumMapping() {
static constexpr std::pair<misc::UseInternalLinkageCheck::FixModeKind,
StringRef>
Mapping[] = {
{misc::UseInternalLinkageCheck::FixModeKind::None, "None"},
{misc::UseInternalLinkageCheck::FixModeKind::UseStatic,
"UseStatic"},
};
return {Mapping};
}
};
} // namespace clang::tidy
namespace clang::tidy::misc {
namespace {
AST_MATCHER(Decl, isFirstDecl) { return Node.isFirstDecl(); }
AST_MATCHER(FunctionDecl, hasBody) { return Node.hasBody(); }
static bool isInMainFile(SourceLocation L, SourceManager &SM,
const FileExtensionsSet &HeaderFileExtensions) {
for (;;) {
if (utils::isExpansionLocInHeaderFile(L, SM, HeaderFileExtensions))
return false;
if (SM.isInMainFile(L))
return true;
// not in header file but not in main file
L = SM.getIncludeLoc(SM.getFileID(L));
if (L.isValid())
continue;
// Conservative about the unknown
return false;
}
}
AST_MATCHER_P(Decl, isAllRedeclsInMainFile, FileExtensionsSet,
HeaderFileExtensions) {
return llvm::all_of(Node.redecls(), [&](const Decl *D) {
return isInMainFile(D->getLocation(),
Finder->getASTContext().getSourceManager(),
HeaderFileExtensions);
});
}
AST_POLYMORPHIC_MATCHER(isExternStorageClass,
AST_POLYMORPHIC_SUPPORTED_TYPES(FunctionDecl,
VarDecl)) {
return Node.getStorageClass() == SC_Extern;
}
AST_MATCHER(FunctionDecl, isAllocationOrDeallocationOverloadedFunction) {
// [basic.stc.dynamic.allocation]
// An allocation function that is not a class member function shall belong to
// the global scope and not have a name with internal linkage.
// [basic.stc.dynamic.deallocation]
// A deallocation function that is not a class member function shall belong to
// the global scope and not have a name with internal linkage.
static const llvm::DenseSet<OverloadedOperatorKind> OverloadedOperators{
OverloadedOperatorKind::OO_New,
OverloadedOperatorKind::OO_Array_New,
OverloadedOperatorKind::OO_Delete,
OverloadedOperatorKind::OO_Array_Delete,
};
return OverloadedOperators.contains(Node.getOverloadedOperator());
}
} // namespace
UseInternalLinkageCheck::UseInternalLinkageCheck(StringRef Name,
ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
HeaderFileExtensions(Context->getHeaderFileExtensions()),
FixMode(Options.get("FixMode", FixModeKind::UseStatic)) {}
void UseInternalLinkageCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "FixMode", FixMode);
}
void UseInternalLinkageCheck::registerMatchers(MatchFinder *Finder) {
auto Common =
allOf(isFirstDecl(), isAllRedeclsInMainFile(HeaderFileExtensions),
unless(anyOf(
// 1. internal linkage
isStaticStorageClass(), isInAnonymousNamespace(),
// 2. explicit external linkage
isExternStorageClass(), isExternC(),
// 3. template
isExplicitTemplateSpecialization(),
hasAncestor(decl(anyOf(
// 4. friend
friendDecl(),
// 5. module export decl
exportDecl()))))));
Finder->addMatcher(
functionDecl(Common, hasBody(),
unless(anyOf(cxxMethodDecl(), isConsteval(),
isAllocationOrDeallocationOverloadedFunction(),
isMain())))
.bind("fn"),
this);
Finder->addMatcher(
varDecl(Common, hasGlobalStorage(), unless(hasThreadStorageDuration()))
.bind("var"),
this);
}
static constexpr StringRef Message =
"%0 %1 can be made static or moved into an anonymous namespace "
"to enforce internal linkage";
void UseInternalLinkageCheck::check(const MatchFinder::MatchResult &Result) {
if (const auto *FD = Result.Nodes.getNodeAs<FunctionDecl>("fn")) {
DiagnosticBuilder DB = diag(FD->getLocation(), Message) << "function" << FD;
const SourceLocation FixLoc = FD->getInnerLocStart();
if (FixLoc.isInvalid() || FixLoc.isMacroID())
return;
if (FixMode == FixModeKind::UseStatic)
DB << FixItHint::CreateInsertion(FixLoc, "static ");
return;
}
if (const auto *VD = Result.Nodes.getNodeAs<VarDecl>("var")) {
// In C++, const variables at file scope have implicit internal linkage,
// so we should not warn there. This is not the case in C.
// https://eel.is/c++draft/diff#basic-3
if (getLangOpts().CPlusPlus && VD->getType().isConstQualified())
return;
DiagnosticBuilder DB = diag(VD->getLocation(), Message) << "variable" << VD;
const SourceLocation FixLoc = VD->getInnerLocStart();
if (FixLoc.isInvalid() || FixLoc.isMacroID())
return;
if (FixMode == FixModeKind::UseStatic)
DB << FixItHint::CreateInsertion(FixLoc, "static ");
return;
}
llvm_unreachable("");
}
} // namespace clang::tidy::misc
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