| # Copyright 2025 The Bazel Authors. All rights reserved. |
| # |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| |
| load(":common/cc/cc_helper_internal.bzl", "should_create_per_object_debug_info") |
| |
| cc_common_internal = _builtins.internal.cc_common |
| cc_internal = _builtins.internal.cc_internal |
| |
| def create_lto_backends( |
| actions, |
| lto_compilation_context, |
| feature_configuration, |
| cc_toolchain, |
| use_pic, |
| object_file_inputs, |
| lto_output_root_prefix, |
| lto_obj_root_prefix, |
| static_libraries_to_link, |
| allow_lto_indexing, |
| include_link_static_in_lto_indexing, |
| prefer_pic_libs): |
| cpp_config = cc_toolchain._cpp_configuration |
| debug = should_create_per_object_debug_info(feature_configuration, cpp_config) |
| |
| compiled = set() |
| static_library_files = set() |
| for lib in static_libraries_to_link: |
| pic = (prefer_pic_libs and lib.pic_static_library != None) or \ |
| lib.static_library == None |
| library_file = lib.pic_static_library if pic else lib.static_library |
| if library_file in static_library_files: |
| # Duplicated static libraries are linked just once and don't error out. |
| # TODO(b/413333884): Clean up violations and error out |
| continue |
| static_library_files.add(library_file) |
| context = lib._pic_lto_compilation_context if pic else lib._lto_compilation_context |
| if context: |
| compiled.update(context.lto_bitcode_inputs().keys()) |
| |
| all_bitcode = [] |
| # Since this link includes object files from another library, we know that library must be |
| # statically linked, so we need to look at includeLinkStaticInLtoIndexing to decide whether |
| # to include its objects in the LTO indexing for this target. |
| |
| if include_link_static_in_lto_indexing: |
| for lib in static_libraries_to_link: |
| if not lib._contains_objects: |
| continue |
| pic = (prefer_pic_libs and lib.pic_static_library != None) or \ |
| lib.static_library == None |
| objects = lib.pic_objects if pic else lib.objects |
| for obj in objects: |
| if obj in compiled: |
| all_bitcode.append(obj) |
| |
| for obj in object_file_inputs: |
| if obj in lto_compilation_context.lto_bitcode_inputs(): |
| all_bitcode.append(obj) |
| |
| if lto_output_root_prefix == lto_obj_root_prefix: |
| for file in all_bitcode: |
| if file.is_directory: |
| fail("Thinlto with tree artifacts requires feature use_lto_native_object_directory.") |
| |
| # Make this a NestedSet to return from LtoBackendAction.getAllowedDerivedInputs. For M binaries |
| # and N .o files, this is O(M*N). If we had nested sets of bitcode files, it would be O(M + N). |
| all_bitcode_depset = depset(all_bitcode) |
| lto_outputs = [] |
| for lib in static_libraries_to_link: |
| if not lib._contains_objects: |
| continue |
| pic = (prefer_pic_libs and lib.pic_static_library != None) or \ |
| lib.static_library == None |
| objects = lib.pic_objects if pic else lib.objects |
| lib_lto_compilation_context = lib._pic_lto_compilation_context if pic else lib._lto_compilation_context |
| shared_lto_backends = lib._pic_shared_non_lto_backends if pic else lib._shared_non_lto_backends |
| |
| for obj in objects: |
| if obj not in compiled: |
| continue |
| if include_link_static_in_lto_indexing: |
| backend_user_compile_flags = _backend_user_compile_flags(cpp_config, obj, lib_lto_compilation_context) |
| lto_outputs.append(cc_common_internal.create_lto_backend_artifacts( |
| actions = actions, |
| lto_output_root_prefix = lto_output_root_prefix, |
| lto_obj_root_prefix = lto_obj_root_prefix, |
| bitcode_file = obj, |
| all_bitcode_files = all_bitcode_depset, |
| feature_configuration = feature_configuration, |
| cc_toolchain = cc_toolchain, |
| fdo_context = cc_toolchain._fdo_context, #TODO: remove |
| use_pic = use_pic, |
| should_create_per_object_debug_info = debug, |
| argv = backend_user_compile_flags, |
| )) |
| else: |
| if not shared_lto_backends: |
| fail(("Statically linked test target requires non-LTO backends for its library inputs," + |
| " but library input %s does not specify shared_non_lto_backends") % lib) |
| lto_outputs.append(shared_lto_backends[obj]) |
| |
| for obj in object_file_inputs: |
| if obj not in lto_compilation_context.lto_bitcode_inputs(): |
| continue |
| backend_user_compile_flags = _backend_user_compile_flags(cpp_config, obj, lto_compilation_context) |
| lto_outputs.append(cc_common_internal.create_lto_backend_artifacts( |
| actions = actions, |
| lto_output_root_prefix = lto_output_root_prefix, |
| lto_obj_root_prefix = lto_obj_root_prefix, |
| bitcode_file = obj, |
| all_bitcode_files = all_bitcode_depset if allow_lto_indexing else None, |
| feature_configuration = feature_configuration, |
| cc_toolchain = cc_toolchain, |
| fdo_context = cc_toolchain._fdo_context, #TODO: remove |
| use_pic = use_pic, |
| should_create_per_object_debug_info = debug, |
| create_shared_non_lto = not allow_lto_indexing, |
| argv = backend_user_compile_flags, |
| )) |
| return lto_outputs |
| |
| def _backend_user_compile_flags(cpp_config, obj, context): |
| argv = [] |
| lto_bitcode_files = context.lto_bitcode_inputs() |
| if obj in lto_bitcode_files: |
| argv.extend(lto_bitcode_files[obj].copts) |
| argv.extend(cpp_config.lto_backend_options) |
| argv.extend(cc_internal.collect_per_file_lto_backend_opts(cpp_config, obj)) |
| return argv |
| |
| def create_shared_non_lto_artifacts( |
| actions, |
| lto_compilation_context, |
| is_linker, |
| feature_configuration, |
| cc_toolchain, |
| use_pic, |
| object_file_inputs): |
| # Only create the shared LTO artifacts for a statically linked library that has bitcode files. |
| if not lto_compilation_context or is_linker: |
| return {} |
| |
| lto_output_root_prefix = "shared.nonlto" |
| if feature_configuration.is_enabled("use_lto_native_object_directory"): |
| lto_obj_root_prefix = "shared.nonlto-obj" |
| else: |
| lto_obj_root_prefix = "shared.nonlto" |
| cpp_config = cc_toolchain._cpp_configuration |
| debug = should_create_per_object_debug_info(feature_configuration, cpp_config) |
| |
| shared_non_lto_backends = {} |
| for obj in object_file_inputs: |
| if obj not in lto_compilation_context.lto_bitcode_inputs(): |
| continue |
| |
| backend_user_compile_flags = _backend_user_compile_flags(cpp_config, obj, lto_compilation_context) |
| shared_non_lto_backends[obj] = cc_common_internal.create_lto_backend_artifacts( |
| actions = actions, |
| lto_output_root_prefix = lto_output_root_prefix, |
| lto_obj_root_prefix = lto_obj_root_prefix, |
| bitcode_file = obj, |
| all_bitcode_files = None, |
| feature_configuration = feature_configuration, |
| cc_toolchain = cc_toolchain, |
| fdo_context = cc_toolchain._fdo_context, #TODO: remove |
| use_pic = use_pic, |
| should_create_per_object_debug_info = debug, |
| create_shared_non_lto = True, |
| argv = backend_user_compile_flags, |
| ) |
| return shared_non_lto_backends |
