Support passing extra linker flags to the relinker

Summary: It's possible for a build to only want a specific optimization during the final phase of linking (aka relinker stage). An example would be to only run LTO during the relinker stage since LTO can incur a high build speed cost. We've tested internally that this doesn't affect APK size is neutral, but we'll still need to run perf tests. Support this flag as a general case so we can also run other specific optimizations only during relinker stage.

Reviewed By: smeenai

Differential Revision: D69625538

fbshipit-source-id: e934b6e076853f5b3593d704d09d539355e20ebc

prelude/android/android_binary_native_library_rules.bzl

@@ -1661,6 +1661,7 @@ def relink_libraries(ctx: AnalysisContext, libraries_by_platform: dict[str, dict
             relinker_link_args = (
                 original_shared_library.link_args +
                 [LinkArgs(flags = [cmd_args(relinker_version_script, format = "-Wl,--version-script={}")])] +
+                [LinkArgs(flags = ctx.attrs.relinker_extra_args)] +
                 ([LinkArgs(infos = [set_link_info_link_whole(red_linkable[1]) for red_linkable in red_linkables[platform]])] if len(red_linkables) > 0 else [])
             )
 

prelude/decls/android_rules.bzl

@@ -139,6 +139,7 @@ android_aar = prelude_rule(
             "never_mark_as_unused_dependency": attrs.option(attrs.bool(), default = None),
             "on_unused_dependencies": attrs.option(attrs.enum(UnusedDependenciesAction), default = None),
             "proguard_config": attrs.option(attrs.source(), default = None),
+            "relinker_extra_args": attrs.list(attrs.arg(), default = [], doc = "Extra arguments passed when relinking all libraries."),
             "relinker_extra_deps": attrs.list(attrs.dep(), default = [], doc = "Deps statically linked to every native lib by the relinker."),
             "relinker_whitelist": attrs.list(attrs.regex(), default = []),
             "required_for_source_only_abi": attrs.bool(default = False),
@@ -256,6 +257,7 @@ android_binary = prelude_rule(
             "primary_dex_patterns": attrs.list(attrs.string(), default = []),
             "proguard_config": attrs.option(attrs.source(), default = None),
             "proguard_jvm_args": attrs.list(attrs.string(), default = []),
+            "relinker_extra_args": attrs.list(attrs.arg(), default = [], doc = "Extra arguments passed when relinking all libraries."),
             "relinker_extra_deps": attrs.list(attrs.dep(), default = [], doc = "Deps statically linked to every native lib by the relinker."),
             "relinker_whitelist": attrs.list(attrs.regex(), default = []),
             "resource_compression": attrs.enum(ResourceCompressionMode, default = "disabled"),
@@ -491,6 +493,7 @@ android_bundle = prelude_rule(
             "primary_dex_patterns": attrs.list(attrs.string(), default = []),
             "proguard_config": attrs.option(attrs.source(), default = None),
             "proguard_jvm_args": attrs.list(attrs.string(), default = []),
+            "relinker_extra_args": attrs.list(attrs.arg(), default = [], doc = "Extra arguments passed when relinking all libraries."),
             "relinker_extra_deps": attrs.list(attrs.dep(), default = [], doc = "Deps statically linked to every native lib by the relinker."),
             "relinker_whitelist": attrs.list(attrs.regex(), default = []),
             "resource_compression": attrs.enum(ResourceCompressionMode, default = "disabled"),