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Richard Smith
c0b24047dd
Add a new builtin function `cpp.std.initializer_list.make` that takes an array and returns a `std::initializer_list`, initialized to refer to that array. When C++ initialization wants to perform a `std::initializer_list`-from-array construction, synthesize a declaration of a matching builtin function and use that to perform the initialization. Ideally we would specify this conversion as an impl of `ImplicitAs` in the prelude instead of hardcoding it in the interop layer, but unfortunately that's not currently possible, for various reasons -- we can't make the conversion form-generic, we can't deduce the array length from the initializer, and we can't deduce against the arguments of imported C++ class templates yet -- so for now synthesizing a builtin function on demand is the best we can do. Assisted-by: Gemini 3 Pro via Antigravity
39 lines
1.3 KiB
C++
39 lines
1.3 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_SEM_IR_CPP_INITIALIZER_LIST_H_
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#define CARBON_TOOLCHAIN_SEM_IR_CPP_INITIALIZER_LIST_H_
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#include "toolchain/sem_ir/ids.h"
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namespace Carbon::SemIR {
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class File;
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// The layout of `std::initializer_list` that we are dealing with.
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struct StdInitializerListLayout {
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enum Kind : int8_t {
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// Not a recognized layout.
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None,
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// `struct { T* begin; T* end; }`
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PointerPointer,
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// `struct { T* begin; size_t size; }`
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PointerInt,
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};
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Kind kind = Kind::None;
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// If the kind is PointerInt, the type of the size.
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TypeId size_type_id = TypeId::None;
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};
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// Returns the kind of `std::initializer_list` that `type_id` represents, or
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// `None` if it is not a `std::initializer_list`. This does not verify that
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// `type_id` is actually a type named `std::initializer_list`, only that it has
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// a recognized set of fields that allows us to treat it as one.
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auto GetStdInitializerListLayout(const File& sem_ir, TypeId type_id)
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-> StdInitializerListLayout;
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} // namespace Carbon::SemIR
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#endif // CARBON_TOOLCHAIN_SEM_IR_CPP_INITIALIZER_LIST_H_
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