[Bazel/C++] Augment `cc_dist_library` to generate lists of source files (#10026)
This change largely moves internal logic that creates the the `CcFileList` provider from `build_systems.bzl` to `cc_dist_library.bzl`.
There are also some associated changes to the particular `cc_dist_library` targets, since the output didn't really make sense after previous BUILD.bazel refactoring. There is also a target now for `libprotoc`.
diff --git a/pkg/cc_dist_library.bzl b/pkg/cc_dist_library.bzl
index d48e8be..383979e 100644
--- a/pkg/cc_dist_library.bzl
+++ b/pkg/cc_dist_library.bzl
@@ -3,12 +3,32 @@
load("@rules_cc//cc:action_names.bzl", cc_action_names = "ACTION_NAMES")
load("@rules_cc//cc:find_cc_toolchain.bzl", "find_cc_toolchain")
+################################################################################
+# Archive/linking support
+################################################################################
+
+def _collect_linker_input_objects(dep_label, cc_info, objs, pic_objs):
+ """Accumulate .o and .pic.o files into `objs` and `pic_objs`."""
+ link_ctx = cc_info.linking_context
+ if link_ctx == None:
+ return
+
+ linker_inputs = link_ctx.linker_inputs.to_list()
+ for link_input in linker_inputs:
+ if link_input.owner != dep_label:
+ # This is a transitive dep: skip it.
+ continue
+
+ for lib in link_input.libraries:
+ objs.extend(lib.objects or [])
+ pic_objs.extend(lib.pic_objects or [])
+
# Creates an action to build the `output_file` static library (archive)
# using `object_files`.
def _create_archive_action(
ctx,
feature_configuration,
- cc_toolchain,
+ cc_toolchain_info,
output_file,
object_files):
# Based on Bazel's src/main/starlark/builtins_bzl/common/cc/cc_import.bzl:
@@ -16,7 +36,7 @@
# Build the command line and add args for all of the input files:
archiver_variables = cc_common.create_link_variables(
feature_configuration = feature_configuration,
- cc_toolchain = cc_toolchain,
+ cc_toolchain = cc_toolchain_info,
output_file = output_file.path,
is_using_linker = False,
)
@@ -48,7 +68,7 @@
inputs = depset(
direct = object_files,
transitive = [
- cc_toolchain.all_files,
+ cc_toolchain_info.all_files,
],
),
use_default_shell_env = False,
@@ -56,72 +76,15 @@
mnemonic = "CppArchiveDist",
)
-# Implementation for cc_dist_library rule.
-def _cc_dist_library_impl(ctx):
- cc_toolchain_info = find_cc_toolchain(ctx)
- if cc_toolchain_info.ar_executable == None:
- return []
-
- feature_configuration = cc_common.configure_features(
- ctx = ctx,
- cc_toolchain = cc_toolchain_info,
- )
-
- # Collect the set of object files from the immediate deps.
-
- objs = []
- pic_objs = []
- for dep in ctx.attr.deps:
- if CcInfo not in dep:
- continue
-
- link_ctx = dep[CcInfo].linking_context
- if link_ctx == None:
- continue
-
- linker_inputs = link_ctx.linker_inputs.to_list()
- for link_input in linker_inputs:
- if link_input.owner != dep.label:
- # This is a transitive dep: skip it.
- continue
-
- for lib in link_input.libraries:
- objs.extend(lib.objects or [])
- pic_objs.extend(lib.pic_objects or [])
-
- # For static libraries, build separately with and without pic.
-
- stemname = "lib" + ctx.label.name
- outputs = []
-
- if len(objs) > 0:
- archive_out = ctx.actions.declare_file(stemname + ".a")
- _create_archive_action(
- ctx,
- feature_configuration,
- cc_toolchain_info,
- archive_out,
- objs,
- )
- outputs.append(archive_out)
-
- if len(pic_objs) > 0:
- pic_archive_out = ctx.actions.declare_file(stemname + ".pic.a")
- _create_archive_action(
- ctx,
- feature_configuration,
- cc_toolchain_info,
- pic_archive_out,
- pic_objs,
- )
- outputs.append(pic_archive_out)
-
- # For dynamic libraries, use the `cc_common.link` command to ensure
- # everything gets built correctly according to toolchain definitions.
-
+def _create_dso_link_action(
+ ctx,
+ feature_configuration,
+ cc_toolchain_info,
+ object_files,
+ pic_object_files):
compilation_outputs = cc_common.create_compilation_outputs(
- objects = depset(objs),
- pic_objects = depset(pic_objs),
+ objects = depset(object_files),
+ pic_objects = depset(pic_object_files),
)
link_output = cc_common.link(
actions = ctx.actions,
@@ -134,6 +97,8 @@
)
library_to_link = link_output.library_to_link
+ outputs = []
+
# Note: library_to_link.dynamic_library and interface_library are often
# symlinks in the solib directory. For DefaultInfo, prefer reporting
# the resolved artifact paths.
@@ -147,6 +112,207 @@
elif library_to_link.interface_library != None:
outputs.append(library_to_link.interface_library)
+ return outputs
+
+################################################################################
+# Source file/header support
+################################################################################
+
+CcFileList = provider(
+ doc = "List of files to be built into a library.",
+ fields = {
+ # As a rule of thumb, `hdrs` and `textual_hdrs` are the files that
+ # would be installed along with a prebuilt library.
+ "hdrs": "public header files, including those used by generated code",
+ "textual_hdrs": "files which are included but are not self-contained",
+
+ # The `internal_hdrs` are header files which appear in `srcs`.
+ # These are only used when compiling the library.
+ "internal_hdrs": "internal header files (only used to build .cc files)",
+ "srcs": "source files",
+ },
+)
+
+def _flatten_target_files(targets):
+ return depset(transitive = [target.files for target in targets])
+
+ files = []
+ for target in targets:
+ files.extend(target.files.to_list())
+ return files
+
+def _cc_file_list_aspect_impl(target, ctx):
+ # Extract sources from a `cc_library` (or similar):
+ if CcInfo not in target:
+ return []
+
+ # We're going to reach directly into the attrs on the traversed rule.
+ rule_attr = ctx.rule.attr
+
+ # CcInfo is a proxy for what we expect this rule to look like.
+ # However, some deps may expose `CcInfo` without having `srcs`,
+ # `hdrs`, etc., so we use `getattr` to handle that gracefully.
+
+ internal_hdrs = []
+ srcs = []
+
+ # Filter `srcs` so it only contains source files. Headers will go
+ # into `internal_headers`.
+ for src in _flatten_target_files(getattr(rule_attr, "srcs", [])).to_list():
+ if src.extension.lower() in ["c", "cc", "cpp", "cxx"]:
+ srcs.append(src)
+ else:
+ internal_hdrs.append(src)
+
+ return [CcFileList(
+ hdrs = _flatten_target_files(getattr(rule_attr, "hdrs", depset())),
+ textual_hdrs = _flatten_target_files(getattr(
+ rule_attr,
+ "textual_hdrs",
+ depset(),
+ )),
+ internal_hdrs = depset(internal_hdrs),
+ srcs = depset(srcs),
+ )]
+
+cc_file_list_aspect = aspect(
+ doc = """
+Aspect to provide the list of sources and headers from a rule.
+
+Output is CcFileList. Example:
+
+ cc_library(
+ name = "foo",
+ srcs = [
+ "foo.cc",
+ "foo_internal.h",
+ ],
+ hdrs = ["foo.h"],
+ textual_hdrs = ["foo_inl.inc"],
+ )
+ # produces:
+ # CcFileList(
+ # hdrs = depset([File("foo.h")]),
+ # textual_hdrs = depset([File("foo_inl.inc")]),
+ # internal_hdrs = depset([File("foo_internal.h")]),
+ # srcs = depset([File("foo.cc")]),
+ # )
+""",
+ implementation = _cc_file_list_aspect_impl,
+)
+
+################################################################################
+# Rule impl
+################################################################################
+
+def _collect_inputs(deps):
+ """Collects files from a list of immediate deps.
+
+ This rule collects source files and linker inputs for C++ deps. Only
+ these immediate deps are considered, not transitive deps.
+
+ The return value is a struct with object files (linker inputs),
+ partitioned by PIC and non-pic, and the rules' source and header files:
+
+ struct(
+ objects = ..., # non-PIC object files
+ pic_objects = ..., # PIC objects
+ cc_file_list = ..., # a CcFileList
+ )
+
+ Args:
+ deps: Iterable of immediate deps. These will be treated as the "inputs,"
+ but not the transitive deps.
+
+ Returns:
+ A struct with linker inputs, source files, and header files.
+ """
+
+ objs = []
+ pic_objs = []
+
+ # The returned CcFileList will contain depsets of the deps' file lists.
+ # These lists hold `depset()`s from each of `deps`.
+ srcs = []
+ hdrs = []
+ internal_hdrs = []
+ textual_hdrs = []
+
+ for dep in deps:
+ if CcInfo in dep:
+ _collect_linker_input_objects(
+ dep.label,
+ dep[CcInfo],
+ objs,
+ pic_objs,
+ )
+
+ if CcFileList in dep:
+ cfl = dep[CcFileList]
+ srcs.append(cfl.srcs)
+ hdrs.append(cfl.hdrs)
+ internal_hdrs.append(cfl.internal_hdrs)
+ textual_hdrs.append(cfl.textual_hdrs)
+
+ return struct(
+ objects = objs,
+ pic_objects = pic_objs,
+ cc_file_list = CcFileList(
+ srcs = depset(transitive = srcs),
+ hdrs = depset(transitive = hdrs),
+ internal_hdrs = depset(transitive = internal_hdrs),
+ textual_hdrs = depset(transitive = textual_hdrs),
+ ),
+ )
+
+# Implementation for cc_dist_library rule.
+def _cc_dist_library_impl(ctx):
+ cc_toolchain_info = find_cc_toolchain(ctx)
+
+ feature_configuration = cc_common.configure_features(
+ ctx = ctx,
+ cc_toolchain = cc_toolchain_info,
+ )
+
+ inputs = _collect_inputs(ctx.attr.deps)
+
+ # For static libraries, build separately with and without pic.
+
+ stemname = "lib" + ctx.label.name
+ outputs = []
+
+ if len(inputs.objects) > 0:
+ archive_out = ctx.actions.declare_file(stemname + ".a")
+ _create_archive_action(
+ ctx,
+ feature_configuration,
+ cc_toolchain_info,
+ archive_out,
+ inputs.objects,
+ )
+ outputs.append(archive_out)
+
+ if len(inputs.pic_objects) > 0:
+ pic_archive_out = ctx.actions.declare_file(stemname + ".pic.a")
+ _create_archive_action(
+ ctx,
+ feature_configuration,
+ cc_toolchain_info,
+ pic_archive_out,
+ inputs.pic_objects,
+ )
+ outputs.append(pic_archive_out)
+
+ # For dynamic libraries, use the `cc_common.link` command to ensure
+ # everything gets built correctly according to toolchain definitions.
+ outputs.extend(_create_dso_link_action(
+ ctx,
+ feature_configuration,
+ cc_toolchain_info,
+ inputs.objects,
+ inputs.pic_objects,
+ ))
+
# We could expose the libraries for use from cc rules:
#
# linking_context = cc_common.create_linking_context(
@@ -169,6 +335,7 @@
return [
DefaultInfo(files = depset(outputs)),
+ inputs.cc_file_list,
]
cc_dist_library = rule(
@@ -214,6 +381,7 @@
"Only these targets' compilation outputs will be " +
"included (i.e., the transitive dependencies are not " +
"included in the output)."),
+ aspects = [cc_file_list_aspect],
),
"linkopts": attr.string_list(
doc = ("Add these flags to the C++ linker command when creating " +
