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David Blaikie
f1f6005d4a
Background: https://docs.google.com/document/d/1wi85FRiWh4X9A-gCYMVGKR40-q5fM6-3JaSpePk-XCY/edit?usp=sharing And specifically this work is essentially an alternative to #5543 Clang's code generation is implemented through an ASTListener (clang::CodeGenerator) that is attached throughout Clang's parsing/sema/code generation phases and acts on Clang AST incrementally throughout that process. Prior to this patch, Carbon has only created the CodeGenerator during Carbon's `lower` phase, missing out on key callbacks that would be made by Clang during `check`. Some of these issues were addressed by #6237 and #6483 - but there were still remaining cases where the delayed processing lead to missing functionality. With #6483 much of the Clang code that made multithreaded complexity of #5543 is no longer present, and we have access to the point of ASTListener registration so we can register the CodeGenerator there and consume its resulting llvm::Module during lower. Examples of some of the bugs this addresses are seen in the linked doc, and checked in as tests in this change in `clang_code_generator_callbacks.carbon` An indicental bug that's also fixed, and caused all the other test case churn, is that the `CodeGenerator` created during `lower` wasn't getting passed the Clang `CodeGenOpts` and was creating its own default - so, most notably, optimization flags were not respected. This meant that the LLVM IR from Clang was always -O0 style IR (optnone, no inlinehint, no TBAA, etc). With this change, now the Clang IRGen gets the real `CodeGenOpts` and respects optimization/other flags specified there. This is only meant to be a rough proof of concept - I'm totally open to reworking this in any way (even quite substantially) if folks have ideas about how this should be implemented most generally/elegantly/etc.
32 lines
1.2 KiB
C++
32 lines
1.2 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_GENERATE_AST_H_
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#define CARBON_TOOLCHAIN_CHECK_CPP_GENERATE_AST_H_
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/IntrusiveRefCntPtr.h"
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#include "llvm/Support/VirtualFileSystem.h"
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#include "toolchain/check/context.h"
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namespace Carbon::Check {
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// Generates a Clang AST for the given C++ imports and sets it as the context's
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// `cpp_context` and the SemIR's `cpp_file`. Returns a bool that represents
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// whether compilation was successful.
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auto GenerateAst(Context& context,
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llvm::ArrayRef<Parse::Tree::PackagingNames> imports,
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llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> fs,
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llvm::LLVMContext* llvm_context,
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std::shared_ptr<clang::CompilerInvocation> base_invocation)
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-> bool;
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// Finishes AST generation for the given checking context. Performs end of file
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// steps such as template instantiation and warning on unused declarations.
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auto FinishAst(Context& context) -> void;
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} // namespace Carbon::Check
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#endif // CARBON_TOOLCHAIN_CHECK_CPP_GENERATE_AST_H_
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