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https://github.com/carbon-language/carbon-lang.git
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Chandler Carruth
d010d52f37
As part of this, move functions that seem reasonable to make out-of-line to a separate `_impl.h` header file that is only included where the explicit instantiation _definition_ is provided. By using explicit instantiation we can make these templates behave more like non-template classes in terms of supporting out-of-line definitions that don't need to be compiled by every translation unit. The set of eventual instantiations here is fundamentally known, and there tend to be headers that define a canonical "leaf" type where it makes sense to trigger the explicit instantiation. Where we already had a `.cpp` file to put the explicit instantiation definition, use it. But in some places we didn't have such a `.cpp` file so this PR adds those. This also requires that we have precise constraints on APIs that _can't_ be instantiated for specific argument types, as now we don't do this lazily. Combined, this appears to reduce the sum of object file sizes in the `check` directory by almost 40% (122mb -> 74mb) in my measurement. My actual goal was to improve compile times, but so far I don't have a great methodology for measuring these... But the object file size reduction seems to confirm this is a net win and likely represents a non-trivial improvement in compile time. Assisted-by: Antigravity with Gemini
66 lines
2.3 KiB
C++
66 lines
2.3 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_GLOBAL_VAR_H_
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#define CARBON_TOOLCHAIN_SEM_IR_CPP_GLOBAL_VAR_H_
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#include "common/hashing.h"
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#include "common/ostream.h"
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#include "toolchain/sem_ir/clang_decl.h"
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#include "toolchain/sem_ir/ids.h"
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namespace Carbon::SemIR {
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// A key describing a C++ global variable imported into Carbon, identified by
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// its entity name.
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struct CppGlobalVarKey : public Printable<CppGlobalVarKey> {
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auto Print(llvm::raw_ostream& out) const -> void {
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out << "{entity_name_id: " << entity_name_id << "}";
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}
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// TODO: Use default when `Printable` supports it.
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friend auto operator==(const CppGlobalVarKey& lhs, const CppGlobalVarKey& rhs)
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-> bool {
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return lhs.entity_name_id == rhs.entity_name_id;
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}
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// The name of the variable.
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EntityNameId entity_name_id;
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};
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// A C++ global variable imported into Carbon. This is used to map the entity
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// name to the Clang declaration so we can use Clang mangling.
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struct CppGlobalVar : public Printable<CppGlobalVar> {
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auto Print(llvm::raw_ostream& out) const -> void {
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out << "{key: " << key << ", clang_decl_id: " << clang_decl_id << "}";
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}
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// The key by which this variable can be looked up.
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CppGlobalVarKey key;
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// The Clang declaration for this variable, if any.
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// This is ignored for equality and hashing, since it's always unique for a
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// given key, in order to store it in `CanonicalValueStore` and allow lookup
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// by `CppGlobalVarKey`.
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ClangDeclId clang_decl_id;
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auto GetAsKey() const -> CppGlobalVarKey { return key; }
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};
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// Use the name of a C++ global variable when doing `Lookup` to find an ID.
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using CppGlobalVarStore = CanonicalValueStore<CppGlobalVarId, CppGlobalVarKey,
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Tag<CheckIRId>, CppGlobalVar>;
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} // namespace Carbon::SemIR
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namespace Carbon {
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extern template class CanonicalValueStore<
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SemIR::CppGlobalVarId, SemIR::CppGlobalVarKey, Tag<SemIR::CheckIRId>,
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SemIR::CppGlobalVar>;
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extern template class ValueStore<SemIR::CppGlobalVarId, SemIR::CppGlobalVar,
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Tag<SemIR::CheckIRId>>;
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} // namespace Carbon
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#endif // CARBON_TOOLCHAIN_SEM_IR_CPP_GLOBAL_VAR_H_
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