Files
clang-p2996/lldb/source/Plugins/ExpressionParser/Clang/CxxModuleHandler.cpp
Pavel Labath c34698a811 [lldb] Rename Logging.h to LLDBLog.h and clean up includes
Most of our code was including Log.h even though that is not where the
"lldb" log channel is defined (Log.h defines the generic logging
infrastructure). This worked because Log.h included Logging.h, even
though it should.

After the recent refactor, it became impossible the two files include
each other in this direction (the opposite inclusion is needed), so this
patch removes the workaround that was put in place and cleans up all
files to include the right thing. It also renames the file to LLDBLog to
better reflect its purpose.
2022-02-03 14:47:01 +01:00

296 lines
9.9 KiB
C++

//===-- CxxModuleHandler.cpp ----------------------------------------------===//
//
// 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 "Plugins/ExpressionParser/Clang/CxxModuleHandler.h"
#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
#include "lldb/Utility/LLDBLog.h"
#include "lldb/Utility/Log.h"
#include "clang/Sema/Lookup.h"
#include "llvm/Support/Error.h"
using namespace lldb_private;
using namespace clang;
CxxModuleHandler::CxxModuleHandler(ASTImporter &importer, ASTContext *target)
: m_importer(&importer),
m_sema(TypeSystemClang::GetASTContext(target)->getSema()) {
std::initializer_list<const char *> supported_names = {
// containers
"array",
"deque",
"forward_list",
"list",
"queue",
"stack",
"vector",
// pointers
"shared_ptr",
"unique_ptr",
"weak_ptr",
// iterator
"move_iterator",
"__wrap_iter",
// utility
"allocator",
"pair",
};
m_supported_templates.insert(supported_names.begin(), supported_names.end());
}
/// Builds a list of scopes that point into the given context.
///
/// \param sema The sema that will be using the scopes.
/// \param ctxt The context that the scope should look into.
/// \param result A list of scopes. The scopes need to be freed by the caller
/// (except the TUScope which is owned by the sema).
static void makeScopes(Sema &sema, DeclContext *ctxt,
std::vector<Scope *> &result) {
// FIXME: The result should be a list of unique_ptrs, but the TUScope makes
// this currently impossible as it's owned by the Sema.
if (auto parent = ctxt->getParent()) {
makeScopes(sema, parent, result);
Scope *scope =
new Scope(result.back(), Scope::DeclScope, sema.getDiagnostics());
scope->setEntity(ctxt);
result.push_back(scope);
} else
result.push_back(sema.TUScope);
}
/// Uses the Sema to look up the given name in the given DeclContext.
static std::unique_ptr<LookupResult>
emulateLookupInCtxt(Sema &sema, llvm::StringRef name, DeclContext *ctxt) {
IdentifierInfo &ident = sema.getASTContext().Idents.get(name);
std::unique_ptr<LookupResult> lookup_result;
lookup_result = std::make_unique<LookupResult>(sema, DeclarationName(&ident),
SourceLocation(),
Sema::LookupOrdinaryName);
// Usually during parsing we already encountered the scopes we would use. But
// here don't have these scopes so we have to emulate the behavior of the
// Sema during parsing.
std::vector<Scope *> scopes;
makeScopes(sema, ctxt, scopes);
// Now actually perform the lookup with the sema.
sema.LookupName(*lookup_result, scopes.back());
// Delete all the allocated scopes beside the translation unit scope (which
// has depth 0).
for (Scope *s : scopes)
if (s->getDepth() != 0)
delete s;
return lookup_result;
}
/// Error class for handling problems when finding a certain DeclContext.
struct MissingDeclContext : public llvm::ErrorInfo<MissingDeclContext> {
static char ID;
MissingDeclContext(DeclContext *context, std::string error)
: m_context(context), m_error(error) {}
DeclContext *m_context;
std::string m_error;
void log(llvm::raw_ostream &OS) const override {
OS << llvm::formatv("error when reconstructing context of kind {0}:{1}",
m_context->getDeclKindName(), m_error);
}
std::error_code convertToErrorCode() const override {
return llvm::inconvertibleErrorCode();
}
};
char MissingDeclContext::ID = 0;
/// Given a foreign decl context, this function finds the equivalent local
/// decl context in the ASTContext of the given Sema. Potentially deserializes
/// decls from the 'std' module if necessary.
static llvm::Expected<DeclContext *>
getEqualLocalDeclContext(Sema &sema, DeclContext *foreign_ctxt) {
// Inline namespaces don't matter for lookups, so let's skip them.
while (foreign_ctxt && foreign_ctxt->isInlineNamespace())
foreign_ctxt = foreign_ctxt->getParent();
// If the foreign context is the TU, we just return the local TU.
if (foreign_ctxt->isTranslationUnit())
return sema.getASTContext().getTranslationUnitDecl();
// Recursively find/build the parent DeclContext.
llvm::Expected<DeclContext *> parent =
getEqualLocalDeclContext(sema, foreign_ctxt->getParent());
if (!parent)
return parent;
// We currently only support building namespaces.
if (foreign_ctxt->isNamespace()) {
NamedDecl *ns = llvm::cast<NamedDecl>(foreign_ctxt);
llvm::StringRef ns_name = ns->getName();
auto lookup_result = emulateLookupInCtxt(sema, ns_name, *parent);
for (NamedDecl *named_decl : *lookup_result) {
if (DeclContext *DC = llvm::dyn_cast<DeclContext>(named_decl))
return DC->getPrimaryContext();
}
return llvm::make_error<MissingDeclContext>(
foreign_ctxt,
"Couldn't find namespace " + ns->getQualifiedNameAsString());
}
return llvm::make_error<MissingDeclContext>(foreign_ctxt, "Unknown context ");
}
/// Returns true iff tryInstantiateStdTemplate supports instantiating a template
/// with the given template arguments.
static bool templateArgsAreSupported(ArrayRef<TemplateArgument> a) {
for (const TemplateArgument &arg : a) {
switch (arg.getKind()) {
case TemplateArgument::Type:
case TemplateArgument::Integral:
break;
default:
// TemplateArgument kind hasn't been handled yet.
return false;
}
}
return true;
}
/// Constructor function for Clang declarations. Ensures that the created
/// declaration is registered with the ASTImporter.
template <typename T, typename... Args>
T *createDecl(ASTImporter &importer, Decl *from_d, Args &&... args) {
T *to_d = T::Create(std::forward<Args>(args)...);
importer.RegisterImportedDecl(from_d, to_d);
return to_d;
}
llvm::Optional<Decl *> CxxModuleHandler::tryInstantiateStdTemplate(Decl *d) {
Log *log = GetLog(LLDBLog::Expressions);
// If we don't have a template to instiantiate, then there is nothing to do.
auto td = dyn_cast<ClassTemplateSpecializationDecl>(d);
if (!td)
return llvm::None;
// We only care about templates in the std namespace.
if (!td->getDeclContext()->isStdNamespace())
return llvm::None;
// We have a list of supported template names.
if (!m_supported_templates.contains(td->getName()))
return llvm::None;
// Early check if we even support instantiating this template. We do this
// before we import anything into the target AST.
auto &foreign_args = td->getTemplateInstantiationArgs();
if (!templateArgsAreSupported(foreign_args.asArray()))
return llvm::None;
// Find the local DeclContext that corresponds to the DeclContext of our
// decl we want to import.
llvm::Expected<DeclContext *> to_context =
getEqualLocalDeclContext(*m_sema, td->getDeclContext());
if (!to_context) {
LLDB_LOG_ERROR(log, to_context.takeError(),
"Got error while searching equal local DeclContext for decl "
"'{1}':\n{0}",
td->getName());
return llvm::None;
}
// Look up the template in our local context.
std::unique_ptr<LookupResult> lookup =
emulateLookupInCtxt(*m_sema, td->getName(), *to_context);
ClassTemplateDecl *new_class_template = nullptr;
for (auto LD : *lookup) {
if ((new_class_template = dyn_cast<ClassTemplateDecl>(LD)))
break;
}
if (!new_class_template)
return llvm::None;
// Import the foreign template arguments.
llvm::SmallVector<TemplateArgument, 4> imported_args;
// If this logic is changed, also update templateArgsAreSupported.
for (const TemplateArgument &arg : foreign_args.asArray()) {
switch (arg.getKind()) {
case TemplateArgument::Type: {
llvm::Expected<QualType> type = m_importer->Import(arg.getAsType());
if (!type) {
LLDB_LOG_ERROR(log, type.takeError(), "Couldn't import type: {0}");
return llvm::None;
}
imported_args.push_back(TemplateArgument(*type));
break;
}
case TemplateArgument::Integral: {
llvm::APSInt integral = arg.getAsIntegral();
llvm::Expected<QualType> type =
m_importer->Import(arg.getIntegralType());
if (!type) {
LLDB_LOG_ERROR(log, type.takeError(), "Couldn't import type: {0}");
return llvm::None;
}
imported_args.push_back(
TemplateArgument(d->getASTContext(), integral, *type));
break;
}
default:
assert(false && "templateArgsAreSupported not updated?");
}
}
// Find the class template specialization declaration that
// corresponds to these arguments.
void *InsertPos = nullptr;
ClassTemplateSpecializationDecl *result =
new_class_template->findSpecialization(imported_args, InsertPos);
if (result) {
// We found an existing specialization in the module that fits our arguments
// so we can treat it as the result and register it with the ASTImporter.
m_importer->RegisterImportedDecl(d, result);
return result;
}
// Instantiate the template.
result = createDecl<ClassTemplateSpecializationDecl>(
*m_importer, d, m_sema->getASTContext(),
new_class_template->getTemplatedDecl()->getTagKind(),
new_class_template->getDeclContext(),
new_class_template->getTemplatedDecl()->getLocation(),
new_class_template->getLocation(), new_class_template, imported_args,
nullptr);
new_class_template->AddSpecialization(result, InsertPos);
if (new_class_template->isOutOfLine())
result->setLexicalDeclContext(
new_class_template->getLexicalDeclContext());
return result;
}
llvm::Optional<Decl *> CxxModuleHandler::Import(Decl *d) {
if (!isValid())
return {};
return tryInstantiateStdTemplate(d);
}