Copy a few utilities from `@_builtins` to `@rules_cc`

PiperOrigin-RevId: 672519388
Change-Id: Icb077dd736af10724ffdbfb8330564516b43fb1d

cc/common/BUILD

@@ -25,6 +25,24 @@ bzl_library(
     name = "cc_helper_bzl",
     srcs = ["cc_helper.bzl"],
     visibility = ["//visibility:public"],
+    deps = [":visibility_bzl"],
+)
+
+bzl_library(
+    name = "cc_debug_helper_bzl",
+    srcs = ["cc_debug_helper.bzl"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":cc_helper_bzl",
+        ":visibility_bzl",
+        "//cc:find_cc_toolchain_bzl",
+    ],
+)
+
+bzl_library(
+    name = "visibility_bzl",
+    srcs = ["visibility.bzl"],
+    visibility = ["//visibility:private"],
 )
 
 filegroup(

cc/common/cc_debug_helper.bzl

@@ -0,0 +1,181 @@
+# Copyright 2024 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.
+"""Utilities for creating cc debug package information outputs"""
+
+load("//cc:find_cc_toolchain.bzl", "CC_TOOLCHAIN_TYPE")
+load(":cc_helper.bzl", "linker_mode")
+load(":visibility.bzl", "INTERNAL_VISIBILITY")
+
+visibility(INTERNAL_VISIBILITY)
+
+def create_debug_packager_actions(
+        ctx,
+        cc_toolchain,
+        dwp_output,
+        *,
+        cc_compilation_outputs,
+        cc_debug_context,
+        linking_mode,
+        use_pic = True,
+        lto_artifacts = []):
+    """Creates intermediate and final dwp creation action(s)
+
+    Args:
+        ctx: (RuleContext) the rule context
+        cc_toolchain: (CcToolchainInfo) the cc toolchain
+        dwp_output: (File) the output of the final dwp action
+        cc_compilation_outputs: (CcCompilationOutputs)
+        cc_debug_context: (DebugContext)
+        linking_mode: (str) See cc_helper.bzl%linker_mode
+        use_pic: (bool)
+        lto_artifacts: ([CcLtoBackendArtifacts])
+    """
+    dwo_files = _collect_transitive_dwo_artifacts(
+        cc_compilation_outputs,
+        cc_debug_context,
+        linking_mode,
+        use_pic,
+        lto_artifacts,
+    )
+
+    # No inputs? Just generate a trivially empty .dwp.
+    #
+    # Note this condition automatically triggers for any build where fission is disabled.
+    # Because rules referencing .dwp targets may be invoked with or without fission, we need
+    # to support .dwp generation even when fission is disabled. Since no actual functionality
+    # is expected then, an empty file is appropriate.
+    dwo_files_list = dwo_files.to_list()
+    if len(dwo_files_list) == 0:
+        ctx.actions.write(dwp_output, "", False)
+        return
+
+    # We apply a hierarchical action structure to limit the maximum number of inputs to any
+    # single action.
+    #
+    # While the dwp tool consumes .dwo files, it can also consume intermediate .dwp files,
+    # allowing us to split a large input set into smaller batches of arbitrary size and order.
+    # Aside from the parallelism performance benefits this offers, this also reduces input
+    # size requirements: if a.dwo, b.dwo, c.dwo, and e.dwo are each 1 KB files, we can apply
+    # two intermediate actions DWP(a.dwo, b.dwo) --> i1.dwp and DWP(c.dwo, e.dwo) --> i2.dwp.
+    # When we then apply the final action DWP(i1.dwp, i2.dwp) --> finalOutput.dwp, the inputs
+    # to this action will usually total far less than 4 KB.
+    #
+    # The actions form an n-ary tree with n == MAX_INPUTS_PER_DWP_ACTION. The tree is fuller
+    # at the leaves than the root, but that both increases parallelism and reduces the final
+    # action's input size.
+    packager = _create_intermediate_dwp_packagers(ctx, dwp_output, cc_toolchain, cc_toolchain._dwp_files, dwo_files_list, 1)
+    packager["outputs"].append(dwp_output)
+    packager["arguments"].add("-o", dwp_output)
+    ctx.actions.run(
+        mnemonic = "CcGenerateDwp",
+        tools = packager["tools"],
+        executable = packager["executable"],
+        toolchain = CC_TOOLCHAIN_TYPE,
+        arguments = [packager["arguments"]],
+        inputs = packager["inputs"],
+        outputs = packager["outputs"],
+    )
+
+def _collect_transitive_dwo_artifacts(cc_compilation_outputs, cc_debug_context, linking_mode, use_pic, lto_backend_artifacts):
+    dwo_files = []
+    transitive_dwo_files = depset()
+    if use_pic:
+        dwo_files.extend(cc_compilation_outputs.pic_dwo_files())
+    else:
+        dwo_files.extend(cc_compilation_outputs.dwo_files())
+
+    if lto_backend_artifacts != None:
+        for lto_backend_artifact in lto_backend_artifacts:
+            if lto_backend_artifact.dwo_file() != None:
+                dwo_files.append(lto_backend_artifact.dwo_file())
+
+    if linking_mode != linker_mode.LINKING_DYNAMIC:
+        if use_pic:
+            transitive_dwo_files = cc_debug_context.pic_files
+        else:
+            transitive_dwo_files = cc_debug_context.files
+    return depset(dwo_files, transitive = [transitive_dwo_files])
+
+def _get_intermediate_dwp_file(ctx, dwp_output, order_number):
+    output_path = dwp_output.short_path
+
+    # Since it is a dwp_output we can assume that it always
+    # ends with .dwp suffix, because it is declared so in outputs
+    # attribute.
+    extension_stripped_output_path = output_path[0:len(output_path) - 4]
+    intermediate_path = extension_stripped_output_path + "-" + str(order_number) + ".dwp"
+
+    return ctx.actions.declare_file("_dwps/" + intermediate_path)
+
+def _create_intermediate_dwp_packagers(ctx, dwp_output, cc_toolchain, dwp_files, dwo_files, intermediate_dwp_count):
+    intermediate_outputs = dwo_files
+
+    # This long loop is a substitution for recursion, which is not currently supported in Starlark.
+    for _ in range(2147483647):
+        packagers = []
+        current_packager = _new_dwp_action(ctx, cc_toolchain, dwp_files)
+        inputs_for_current_packager = 0
+
+        # Step 1: generate our batches. We currently break into arbitrary batches of fixed maximum
+        # input counts, but we can always apply more intelligent heuristics if the need arises.
+        for dwo_file in intermediate_outputs:
+            if inputs_for_current_packager == 100:
+                packagers.append(current_packager)
+                current_packager = _new_dwp_action(ctx, cc_toolchain, dwp_files)
+                inputs_for_current_packager = 0
+            current_packager["inputs"].append(dwo_file)
+
+            # add_all expands all directories to their contained files, see
+            # https://bazel.build/rules/lib/builtins/Args#add_all. add doesn't
+            # do that, so using add_all on the one-item list here allows us to
+            # find dwo files in directories.
+            current_packager["arguments"].add_all([dwo_file])
+            inputs_for_current_packager += 1
+
+        packagers.append(current_packager)
+
+        # Step 2: given the batches, create the actions.
+        if len(packagers) > 1:
+            # If we have multiple batches, make them all intermediate actions, then pipe their outputs
+            # into an additional level.
+            intermediate_outputs = []
+            for packager in packagers:
+                intermediate_output = _get_intermediate_dwp_file(ctx, dwp_output, intermediate_dwp_count)
+                intermediate_dwp_count += 1
+                packager["outputs"].append(intermediate_output)
+                packager["arguments"].add("-o", intermediate_output)
+                ctx.actions.run(
+                    mnemonic = "CcGenerateIntermediateDwp",
+                    tools = packager["tools"],
+                    executable = packager["executable"],
+                    toolchain = CC_TOOLCHAIN_TYPE,
+                    arguments = [packager["arguments"]],
+                    inputs = packager["inputs"],
+                    outputs = packager["outputs"],
+                )
+                intermediate_outputs.append(intermediate_output)
+        else:
+            return packagers[0]
+
+    # This is to fix buildifier errors, even though we should never reach this part of the code.
+    return None
+
+def _new_dwp_action(ctx, cc_toolchain, dwp_tools):
+    return {
+        "arguments": ctx.actions.args(),
+        "executable": cc_toolchain._tool_paths.get("dwp", None),
+        "inputs": [],
+        "outputs": [],
+        "tools": dwp_tools,
+    }

cc/common/cc_helper.bzl

@@ -11,10 +11,82 @@
 # 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.
-
 """Utility functions for C++ rules."""
 
-# LINT.IfChange
+load("//cc:find_cc_toolchain.bzl", "CC_TOOLCHAIN_TYPE")
+load(":cc_common.bzl", "cc_common")
+load(":visibility.bzl", "INTERNAL_VISIBILITY")
+
+visibility(INTERNAL_VISIBILITY)
+
+# LINT.IfChange(linker_mode)
+linker_mode = struct(
+    LINKING_DYNAMIC = "dynamic_linking_mode",
+    LINKING_STATIC = "static_linking_mode",
+)
+# LINT.ThenChange(https://github.com/bazelbuild/bazel/blob/master/src/main/starlark/builtins_bzl/common/cc/cc_helper.bzl:linker_mode)
+
+# LINT.IfChange(forked_exports)
+def _get_static_mode_params_for_dynamic_library_libraries(libs):
+    linker_inputs = []
+    for lib in libs.to_list():
+        if lib.pic_static_library:
+            linker_inputs.append(lib.pic_static_library)
+        elif lib.static_library:
+            linker_inputs.append(lib.static_library)
+        elif lib.interface_library:
+            linker_inputs.append(lib.interface_library)
+        else:
+            linker_inputs.append(lib.dynamic_library)
+    return linker_inputs
+
+def _create_strip_action(ctx, cc_toolchain, cpp_config, input, output, feature_configuration):
+    if cc_common.is_enabled(feature_configuration = feature_configuration, feature_name = "no_stripping"):
+        ctx.actions.symlink(
+            output = output,
+            target_file = input,
+            progress_message = "Symlinking original binary as stripped binary",
+        )
+        return
+
+    if not cc_common.action_is_enabled(feature_configuration = feature_configuration, action_name = "strip"):
+        fail("Expected action_config for 'strip' to be configured.")
+
+    variables = cc_common.create_compile_variables(
+        cc_toolchain = cc_toolchain,
+        feature_configuration = feature_configuration,
+        output_file = output.path,
+        input_file = input.path,
+        strip_opts = cpp_config.strip_opts(),
+    )
+    command_line = cc_common.get_memory_inefficient_command_line(
+        feature_configuration = feature_configuration,
+        action_name = "strip",
+        variables = variables,
+    )
+    env = cc_common.get_environment_variables(
+        feature_configuration = feature_configuration,
+        action_name = "strip",
+        variables = variables,
+    )
+    execution_info = {}
+    for execution_requirement in cc_common.get_tool_requirement_for_action(feature_configuration = feature_configuration, action_name = "strip"):
+        execution_info[execution_requirement] = ""
+    ctx.actions.run(
+        inputs = depset(
+            direct = [input],
+            transitive = [cc_toolchain._strip_files],
+        ),
+        outputs = [output],
+        use_default_shell_env = True,
+        env = env,
+        executable = cc_common.get_tool_for_action(feature_configuration = feature_configuration, action_name = "strip"),
+        toolchain = CC_TOOLCHAIN_TYPE,
+        execution_requirements = execution_info,
+        progress_message = "Stripping {} for {}".format(output.short_path, ctx.label),
+        mnemonic = "CcStrip",
+        arguments = command_line,
+    )
 
 def _lookup_var(ctx, additional_vars, var):
     expanded_make_var_ctx = ctx.var.get(var)
@@ -195,9 +267,29 @@ def _tokenize(options, options_string):
     if force_token or len(token) > 0:
         options.append("".join(token))
 
+def _should_use_pic(ctx, cc_toolchain, feature_configuration):
+    """Whether to use pic files
+
+    Args:
+        ctx: (RuleContext)
+        cc_toolchain: (CcToolchainInfo)
+        feature_configuration: (FeatureConfiguration)
+
+    Returns:
+        (bool)
+    """
+    return ctx.fragments.cpp.force_pic() or (
+        cc_toolchain.needs_pic_for_dynamic_libraries(feature_configuration = feature_configuration) and (
+            ctx.var["COMPILATION_MODE"] != "opt" or
+            cc_common.is_enabled(feature_configuration = feature_configuration, feature_name = "prefer_pic_for_opt_binaries")
+        )
+    )
+
 cc_helper = struct(
+    create_strip_action = _create_strip_action,
     get_expanded_env = _get_expanded_env,
+    get_static_mode_params_for_dynamic_library_libraries = _get_static_mode_params_for_dynamic_library_libraries,
+    should_use_pic = _should_use_pic,
     tokenize = _tokenize,
 )
-
-# LINT.ThenChange(https://github.com/bazelbuild/bazel/blob/master/src/main/starlark/builtins_bzl/common/cc/cc_helper.bzl)
+# LINT.ThenChange(https://github.com/bazelbuild/bazel/blob/master/src/main/starlark/builtins_bzl/common/cc/cc_helper.bzl:forked_exports)

cc/common/visibility.bzl

@@ -0,0 +1,3 @@
+"""Bzl load visibility package specs"""
+
+INTERNAL_VISIBILITY = ["//cc/..."]