mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 22:02:23 +01:00
Chandler Carruth
7901fb3857
Fundamentally, this uses forward declarations of Clang types to reduce the overall compile time cost of Clang headers across the codebase. Tracing and profiling showed ~2s of every check TU's ~8-12s compile time going just to parsing Clang frontend and AST headers pulled in via a few sem_ir and check headers that only use the Clang types by pointer or reference: - sem_ir/cpp_file.h (reached via sem_ir/file.h by ~150 TUs) included clang/Frontend/CompilerInstance.h, clang/CodeGen/ModuleBuilder.h, clang/AST/Mangle.h, and llvm/IR/Module.h. CppFile's accessors move out of line to a new cpp_file.cpp and the header now forward-declares the Clang types. - check/cpp/context.h (reached via check/context.h by ~100 TUs) included clang/Frontend/FrontendAction.h and clang/Parse/Parser.h, pulling in clang's Sema.h and ASTUnit.h. - sem_ir/clang_decl.h included clang/AST/Decl.h; the three small functions that need complete Clang types move out of line. - sem_ir/cpp_overload_set.h included clang/Sema/Overload.h solely for the three-field OverloadCandidateSet::OperatorRewriteInfo, which is now mirrored as CppOverloadSet::OperatorRewriteInfo, and clang/AST/Decl.h solely for a pointer. - sem_ir/name_scope.h's clang/AST/DeclBase.h include was vestigial. TUs (and more narrowly included headers) that genuinely use the Clang definitions now include the Clang headers directly. Representative compile times (fastbuild, aarch64), combined with the preceding instantiation-cost changes, relative to trunk: - check/eval.cpp: 11.85s -> 6.94s (-41%) - check/handle_operator.cpp: 7.71s -> 3.30s (-57%) - language_server.cpp: 6.68s -> 3.16s (-53%) - lower/handle.cpp: 6.75s -> 3.66s (-46%) - sem_ir/file.cpp: 8.60s -> 6.11s (-29%) - driver.cpp: 6.68s -> 4.78s (-28%) Measured full-rebuild impact (316 first-party TUs, fastbuild): -689.5s CPU, -29.9% relative to trunk. Assisted-by: Claude
65 lines
2.8 KiB
C++
65 lines
2.8 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_CALL_H_
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#define CARBON_TOOLCHAIN_CHECK_CPP_CALL_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 TemplateArgumentListInfo;
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class TemplateDecl;
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} // namespace clang
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namespace Carbon::Check {
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// Converts a call argument list into a Clang template argument list for a given
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// template. Returns true on success, or false if an error was diagnosed.
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//
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// If `diagnose` is false, errors will be suppressed.
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auto ConvertArgsToTemplateArgs(Context& context,
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clang::TemplateDecl* template_decl,
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llvm::ArrayRef<SemIR::InstId> arg_ids,
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clang::TemplateArgumentListInfo& arg_list,
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bool diagnose = true) -> bool;
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// Checks and builds SemIR for a call to a C++ function in the given overload
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// set with self `self_id` and arguments `arg_ids`. `is_desugared`
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// indicates that this call was was produced by desugaring, not written as a
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// function call in user code, so arguments to `ref` parameters aren't required
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// to have `ref` tags.
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//
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// Chooses the best viable C++ function by performing Clang overloading
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// resolution over the overload set.
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//
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// Preserves the given self, if set. If not set, and the function is a C++
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// member operator, self will be set to the first argument, which in turn will
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// be removed from the given args.
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//
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// A set with a single non-templated function goes through the same rules for
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// overloading resolution. This is to make sure that calls that have no viable
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// implicit conversion sequence are rejected even when an implicit conversion is
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// possible. Keeping the same behavior here for consistency and supporting
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// migrations so that the migrated callers from C++ remain valid.
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auto PerformCallToCppFunction(Context& context, SemIR::LocId loc_id,
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SemIR::CppOverloadSetId overload_set_id,
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SemIR::InstId self_id,
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llvm::ArrayRef<SemIR::InstId> arg_ids,
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bool is_desugared) -> SemIR::InstId;
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// Checks and builds SemIR for a call to a C++ template name with arguments
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// `arg_ids`.
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//
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// Converts the arguments to a C++ template argument list and attempts to
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// instantiate a template specialization and import a declaration of it.
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auto PerformCallToCppTemplateName(Context& context, SemIR::LocId loc_id,
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SemIR::ClangDeclId template_decl_id,
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llvm::ArrayRef<SemIR::InstId> arg_ids)
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-> SemIR::InstId;
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} // namespace Carbon::Check
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#endif // CARBON_TOOLCHAIN_CHECK_CPP_CALL_H_
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