[bazel] Add rules for declaring linker scripts as their own targets
Signed-off-by: Miguel Young de la Sota <mcyoung@google.com>
diff --git a/rules/linker.bzl b/rules/linker.bzl
new file mode 100644
index 0000000..cadaa95
--- /dev/null
+++ b/rules/linker.bzl
@@ -0,0 +1,53 @@
+# Copyright lowRISC contributors.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+"""Rules for declaring linker scripts and linker script fragments."""
+
+def _ld_library_impl(ctx):
+ files = [] + ctx.files.fragments
+ user_link_flags = []
+ if ctx.file.script:
+ files += ctx.files.script
+ user_link_flags += [
+ "-Wl,-T,{}".format(ctx.file.script.path),
+ ]
+
+ return [
+ cc_common.merge_cc_infos(
+ direct_cc_infos = [CcInfo(
+ linking_context = cc_common.create_linking_context(
+ linker_inputs = depset([cc_common.create_linker_input(
+ owner = ctx.label,
+ additional_inputs = depset(files),
+ user_link_flags = depset(user_link_flags),
+ )]),
+ ),
+ )],
+ cc_infos = [dep[CcInfo] for dep in ctx.attr.deps],
+ ),
+ ]
+
+ld_library = rule(
+ implementation = _ld_library_impl,
+ doc = """
+ A linker script library. Linker script libraries consist of a collection of
+ "fragments" (the linker equivalent of a header) and an optional script. Linker
+ script libraries can depend on other libraries to access the fragments they
+ public; cc_binaries can depend on an ld_library with a script to specify it
+ as the linker script for that binary.
+
+ At most one ld_library in a cc_binary's dependencies may have a script.
+ """,
+ attrs = {
+ "script": attr.label(allow_single_file = True),
+ "fragments": attr.label_list(
+ default = [],
+ allow_files = True,
+ ),
+ "deps": attr.label_list(
+ default = [],
+ providers = [CcInfo],
+ ),
+ },
+)
\ No newline at end of file
