Use objcopy instead of dump for symbols

We keep the file name as `objdump` to not break customers consuming
these symbols.

BUILD

@@ -112,7 +112,7 @@ android_debug_info(
 genrule(
     name = "capture_symbols",
     srcs = [
-        ":capture_aar_objdump_collector",
+        ":capture_aar_symbols_collector",
     ],
     outs = ["symbols.tar"],
     cmd = """

bazel/android/artifacts.bzl

@@ -63,9 +63,9 @@ def android_artifacts(name, android_library, manifest, archive_name, native_deps
     aar_output = _create_aar(name, classes_jar, jni_archive, proguard_rules, manifest, visibility)
 
     native.filegroup(
-        name = name + "_objdump_collector",
+        name = name + "_symbols_collector",
         srcs = native_deps,
-        output_group = "objdump",
+        output_group = "objcopy",
         visibility = ["//visibility:public"],
     )
 

bazel/android_debug_info.bzl

@@ -1,5 +1,5 @@
 """
-Rule to create objdump debug info from a native dynamic library built for
+Rule to create objcopy debug info from a native dynamic library built for
 Android.
 
 This is a workaround for generally not being able to produce dwp files for
@@ -11,7 +11,7 @@ somehow, this rule provides a separate --output_group for this
 
 def _impl(ctx):
     library_outputs = []
-    objdump_outputs = []
+    objcopy_outputs = []
     for platform, dep in ctx.split_attr.dep.items():
         # When --fat_apk_cpu isn't set, the platform is None
         if len(dep.files.to_list()) != 1:
@@ -20,12 +20,12 @@ def _impl(ctx):
         cc_toolchain = ctx.split_attr._cc_toolchain[platform][cc_common.CcToolchainInfo]
         lib = dep.files.to_list()[0]
         platform_name = platform or ctx.fragments.android.android_cpu
-        objdump_output = ctx.actions.declare_file(platform_name + "/" + platform_name + ".objdump.gz")
+        objcopy_output = ctx.actions.declare_file(platform_name + "/" + platform_name + ".debug.gz")
 
         ctx.actions.run_shell(
             inputs = [lib],
-            outputs = [objdump_output],
-            command = cc_toolchain.objdump_executable + " --syms " + lib.path + "| gzip -c >" + objdump_output.path,
+            outputs = [objcopy_output],
+            command = cc_toolchain.objcopy_executable + " --compress-debug-sections=zlib --only-keep-debug " + lib.path + " - | gzip -c >" + objcopy_output.path,
             tools = [cc_toolchain.all_files],
             progress_message = "Generating symbol map " + platform_name,
         )
@@ -40,11 +40,11 @@ def _impl(ctx):
         )
 
         library_outputs.append(strip_output)
-        objdump_outputs.append(objdump_output)
+        objcopy_outputs.append(objcopy_output)
 
     return [
         DefaultInfo(files = depset(library_outputs)),
-        OutputGroupInfo(objdump = objdump_outputs),
+        OutputGroupInfo(objcopy = objcopy_outputs),
     ]
 
 android_debug_info = rule(