mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-29 10:35:06 +01:00
Nicholas Bishop
c8fdeef911
This allows C++ to call Carbon functions with generic type parameters,
with some conditions. Example:
```carbon
interface I {
fn Doit(self);
}
class A {
impl as I { fn Doit(unused self) {} }
}
class B {
impl as I { fn Doit(unused self) {} }
}
fn F[T:! I](t: T) {
t.Doit();
}
inline Cpp '''
void G() {
Carbon::A a;
Carbon::B b;
Carbon::F(a);
Carbon::F(b);
}
''';
```
The initial support is limited; only explicit parameters are handled
currently.
`CarbonExternalASTSource::GetOrExportFunctionToCpp` now generates a
`clang::FunctionTemplateDecl` for generic Carbon functions. If C++ code
attempts to call that templated function,
`CarbonExternalASTSource::LoadExternalSpecializations` will be called
with the template argument types of that call site. Then we can generate
a specialized thunk for those argument types for C++ to call.
85 lines
3.3 KiB
C++
85 lines
3.3 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#ifndef CARBON_TOOLCHAIN_CHECK_CPP_EXPORT_H_
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#define CARBON_TOOLCHAIN_CHECK_CPP_EXPORT_H_
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#include "clang/AST/Decl.h"
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#include "toolchain/check/context.h"
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#include "toolchain/sem_ir/ids.h"
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namespace clang {
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class CXXDestructorDecl;
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class CXXRecordDecl;
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} // namespace clang
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namespace Carbon::Check {
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// Exports a Carbon name scope into C++ as a namespace or class, or returns the
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// C++ namespace or class declaration that it was imported from.
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//
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// If the name scope has already been exported, returns the existing context.
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// Otherwise, creates a new C++ declaration context and returns it. Returns
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// nullptr if the name scope could not be exported and an error was diagnosed.
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auto ExportNameScopeToCpp(Context& context, SemIR::LocId loc_id,
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SemIR::NameScopeId name_scope_id)
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-> clang::DeclContext*;
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// Exports a Carbon class into C++ as a class, or returns the C++ tag type that
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// the class was imported from.
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//
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// If the class has already been exported, returns the existing C++ class.
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// Otherwise, creates a new C++ class and returns it. Returns nullptr if the
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// class could not be exported and an error was diagnosed.
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auto ExportClassToCpp(Context& context, SemIR::LocId loc_id,
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SemIR::ClassType class_type) -> clang::TagDecl*;
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// Export all `SemIR::FieldDecl`s in the class body as `clang::FieldDecl`s.
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auto ExportAllFieldsToCpp(Context& context, SemIR::Class& class_info) -> void;
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// Exports a Carbon class field into C++.
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//
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// If the field has already been exported, returns the existing C++
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// field.
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//
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// If the field has not already been exported, *all* fields of the class
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// are exported, and then the requested C++ field is returned.
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//
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// Returns nullptr if the class could not be exported and an error was
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// diagnosed.
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auto ExportFieldToCpp(Context& context, SemIR::InstId field_inst_id,
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SemIR::FieldDecl field_decl) -> clang::FieldDecl*;
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// Get a `clang::FunctionDecl` that can be used to call a Carbon function.
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// If the function is generic, a `clang::FunctionTemplateDecl` will be
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// created instead.
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auto ExportFunctionToCpp(Context& context, SemIR::LocId loc_id,
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SemIR::FunctionId function_id) -> clang::NamedDecl*;
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// Creates a C++ function template specialization for a generic Carbon
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// function.
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//
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// Returns true if a specialization was added, false otherwise.
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auto ExportFunctionSpecializationToCpp(
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Context& context, clang::FunctionTemplateDecl* function_template_decl,
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llvm::ArrayRef<clang::TemplateArgument> template_args) -> bool;
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// Export a Carbon destructor into C++.
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//
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// The destructor calls the `Destroy` operator.
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auto ExportDestructorToCpp(Context& context, const SemIR::Class& class_info,
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clang::CXXRecordDecl* record_decl)
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-> clang::CXXDestructorDecl*;
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// Export a Carbon variable into C++.
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//
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// Returns nullptr if the variable could not be exported an an error was
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// diagnosed.
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auto ExportVarToCpp(Context& context, SemIR::InstId inst_id,
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SemIR::VarStorage var_storage) -> clang::VarDecl*;
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} // namespace Carbon::Check
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#endif // CARBON_TOOLCHAIN_CHECK_CPP_EXPORT_H_
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