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CxxModuleHandler.h
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1//===-- CxxModuleHandler.h --------------------------------------*- C++ -*-===//
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#ifndef LLDB_SOURCE_PLUGINS_EXPRESSIONPARSER_CLANG_CXXMODULEHANDLER_H
10#define LLDB_SOURCE_PLUGINS_EXPRESSIONPARSER_CLANG_CXXMODULEHANDLER_H
11
12#include "clang/AST/ASTImporter.h"
13#include "clang/Sema/Sema.h"
14#include "llvm/ADT/StringSet.h"
15#include <optional>
16
17namespace lldb_private {
18
19/// Handles importing decls into an ASTContext with an attached C++ module.
20///
21/// This class searches a C++ module (which must be attached to the target
22/// ASTContext) for an equivalent decl to the one that should be imported.
23/// If the decl that is found in the module is a suitable replacement
24/// for the decl that should be imported, the module decl will be treated as
25/// the result of the import process.
26///
27/// If the Decl that should be imported is a template specialization
28/// that doesn't exist yet in the target ASTContext (e.g. `std::vector<int>`),
29/// then this class tries to create the template specialization in the target
30/// ASTContext. This is only possible if the CxxModuleHandler can determine
31/// that instantiating this template is safe to do, e.g. because the target
32/// decl is a container class from the STL.
34 /// The ASTImporter that should be used to import any Decls which aren't
35 /// directly handled by this class itself.
36 clang::ASTImporter *m_importer = nullptr;
37
38 /// The Sema instance of the target ASTContext.
39 clang::Sema *m_sema = nullptr;
40
41 /// List of template names this class currently supports. These are the
42 /// template names inside the 'std' namespace such as 'vector' or 'list'.
43 llvm::StringSet<> m_supported_templates;
44
45 /// Tries to manually instantiate the given foreign template in the target
46 /// context (designated by m_sema).
47 std::optional<clang::Decl *> tryInstantiateStdTemplate(clang::Decl *d);
48
49public:
50 CxxModuleHandler() = default;
51 CxxModuleHandler(clang::ASTImporter &importer, clang::ASTContext *target);
52
53 /// Attempts to import the given decl into the target ASTContext by
54 /// deserializing it from the 'std' module. This function returns a Decl if a
55 /// Decl has been deserialized from the 'std' module. Otherwise this function
56 /// returns nothing.
57 std::optional<clang::Decl *> Import(clang::Decl *d);
58
59 /// Returns true iff this instance is capable of importing any declarations
60 /// in the target ASTContext.
61 bool isValid() const { return m_sema != nullptr; }
62};
63
64} // namespace lldb_private
65
66#endif // LLDB_SOURCE_PLUGINS_EXPRESSIONPARSER_CLANG_CXXMODULEHANDLER_H
Handles importing decls into an ASTContext with an attached C++ module.
clang::Sema * m_sema
The Sema instance of the target ASTContext.
bool isValid() const
Returns true iff this instance is capable of importing any declarations in the target ASTContext.
CxxModuleHandler(clang::ASTImporter &importer, clang::ASTContext *target)
std::optional< clang::Decl * > Import(clang::Decl *d)
Attempts to import the given decl into the target ASTContext by deserializing it from the 'std' modul...
clang::ASTImporter * m_importer
The ASTImporter that should be used to import any Decls which aren't directly handled by this class i...
std::optional< clang::Decl * > tryInstantiateStdTemplate(clang::Decl *d)
Tries to manually instantiate the given foreign template in the target context (designated by m_sema)...
llvm::StringSet m_supported_templates
List of template names this class currently supports.
A class that represents a running process on the host machine.