Files
carbon-lang/toolchain/check/cpp/location.cpp
T
Richard Smith 6114df59ee Factor out a Check::CppContext holding C++-specific check state (#6482)
* Move `Sema` access from `CppFile` into `CppContext`.
* Move the mangle context from `SemIR::File` into `CppContext`.
* Move source location mapping state from `Context` into `CppContext`.

Also factor out the `GenerateAst` function that builds the `CppContext`
and `CppFile` into its own file.
2025-12-10 18:55:22 +00:00

83 lines
3.1 KiB
C++

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "toolchain/check/cpp/location.h"
#include "toolchain/sem_ir/absolute_node_id.h"
#include "toolchain/sem_ir/ids.h"
namespace Carbon::Check {
namespace {
struct FileInfo {
const SemIR::File* sem_ir;
clang::SourceLocation start_loc;
};
} // namespace
// Map a CheckIRId into information about the corresponding file in both SemIR
// and Clang's source manager.
static auto GetFileInfo(Context& context, SemIR::CheckIRId ir_id) -> FileInfo {
const SemIR::File* sem_ir = &context.sem_ir();
int file_index = 0;
// If the file is imported, locate it in our imports map.
if (ir_id != context.sem_ir().check_ir_id()) {
auto import_id = context.check_ir_map().Get(ir_id);
CARBON_CHECK(import_id.has_value());
file_index = import_id.index + 1;
sem_ir = context.import_irs().Get(import_id).sem_ir;
CARBON_CHECK(sem_ir, "Node location in nonexistent IR");
}
// If we've seen this file before, reuse the same FileID.
auto& file_start_locs = context.cpp_context()->carbon_file_locations();
if (static_cast<int>(file_start_locs.size()) <= file_index) {
// Never valid; prepare a slot for the caching below.
file_start_locs.resize(file_index + 1);
} else if (file_start_locs[file_index].isValid()) {
return {.sem_ir = sem_ir, .start_loc = file_start_locs[file_index]};
}
// We've not seen this file before. Create a corresponding virtual file in
// Clang's source manager.
// TODO: Consider recreating the complete import path instead of only the
// final entry.
const auto& source = sem_ir->parse_tree().tokens().source();
auto& src_mgr = context.ast_context().getSourceManager();
auto file_id = src_mgr.createFileID(
llvm::MemoryBufferRef(source.text(), source.filename()));
auto file_start_loc = src_mgr.getLocForStartOfFile(file_id);
file_start_locs[file_index] = file_start_loc;
return {.sem_ir = sem_ir, .start_loc = file_start_loc};
}
auto GetCppLocation(Context& context, SemIR::LocId loc_id)
-> clang::SourceLocation {
if (!context.sem_ir().cpp_file()) {
return clang::SourceLocation();
}
// Break down the `LocId` into an import path. If that ends in a C++ location,
// we can just return that directly.
llvm::SmallVector<SemIR::AbsoluteNodeId> absolute_node_ids =
SemIR::GetAbsoluteNodeId(&context.sem_ir(), loc_id);
if (absolute_node_ids.back().check_ir_id() == SemIR::CheckIRId::Cpp) {
return context.sem_ir().clang_source_locs().Get(
absolute_node_ids.back().clang_source_loc_id());
}
// This is a location in Carbon code; get or create a corresponding file in
// Clang and build a corresponding location.
auto absolute_node_id = absolute_node_ids.back();
auto [ir, start_loc] = GetFileInfo(context, absolute_node_id.check_ir_id());
const auto& tree = ir->parse_tree();
auto offset =
tree.tokens().GetByteOffset(tree.node_token(absolute_node_id.node_id()));
return start_loc.getLocWithOffset(offset);
}
} // namespace Carbon::Check