Add support for creating D8 compiler input dumps in bazel

This adds support in bazel for easily generating D8 compiler input dump file for the dex merging task. The generated compiler input dump file is a zip file that contains all inputs to the given compilation and makes it easy to reproduce and debug a given compilation.

This can be enabled by adding `--define=generate_d8_dump=true` to a given build command.

See also https://r8.googlesource.com/r8/+/refs/heads/main/doc/compilerdump.md.

PiperOrigin-RevId: 868512663
Change-Id: Ic315105820ddf3907e872b6bc147e137c3714856

Author: A Googler

rules/android_binary/impl.bzl

@@ -325,6 +325,10 @@ def _process_dex(ctx, validation_ctx, packaged_resources_ctx, manifest_ctx, depl
     if should_optimize_dex and acls.in_d8_optimization_metadata(str(ctx.label)):
         build_metadata_output = ctx.actions.declare_file(ctx.label.name + "_d8_optimization_info.json")
 
+    input_dump_output = None
+    if should_optimize_dex and ctx.var.get("generate_d8_dump") == "true":
+        input_dump_output = ctx.actions.declare_file(ctx.label.name + "_d8_dump.zip")
+
     if proguard_output_map:
         # Proguard map from preprocessing will be merged with Proguard map for desugared
         # library.
@@ -373,6 +377,7 @@ def _process_dex(ctx, validation_ctx, packaged_resources_ctx, manifest_ctx, depl
             postprocessing_output_map = postprocessing_output_map,
             startup_profile = optimize_ctx.proguard_output.startup_profile_rewritten,
             build_metadata_output = build_metadata_output,
+            input_dump_output = input_dump_output,
             inclusion_filter_jar = binary_jar if is_instrumentation(ctx) and not is_binary_optimized else None,
             transitive_runtime_jars_for_archive = deploy_ctx.transitive_runtime_jars_for_archive,
             desugar_dict = deploy_ctx.desugar_dict,
@@ -447,13 +452,17 @@ def _process_dex(ctx, validation_ctx, packaged_resources_ctx, manifest_ctx, depl
     if postprocessing_output_map:
         providers.append(ProguardMappingInfo(proguard_mapping = postprocessing_output_map))
 
+    implicit_outputs = [final_proguard_output_map] if final_proguard_output_map else []
+    if input_dump_output:
+        implicit_outputs.append(input_dump_output)
+
     return ProviderInfo(
         name = "dex_ctx",
         value = struct(
             dex_info = dex_info,
             java8_legacy_dex_map = java8_legacy_dex_map,
             providers = providers,
-            implicit_outputs = [final_proguard_output_map] if final_proguard_output_map else [],
+            implicit_outputs = implicit_outputs,
         ),
     )
 

rules/dex.bzl

@@ -52,6 +52,7 @@ def _process_incremental_dexing(
         postprocessing_output_map = None,
         startup_profile = None,
         build_metadata_output = None,
+        input_dump_output = None,
         inclusion_filter_jar = None,
         desugar_dict = {},
         transitive_runtime_jars_for_archive = [],
@@ -173,6 +174,7 @@ def _process_incremental_dexing(
             postprocessing_output_map = postprocessing_output_map,
             startup_profile = startup_profile,
             build_metadata_output = build_metadata_output,
+            input_dump_output = input_dump_output,
             optimizing_dexer = optimizing_dexer,
             min_sdk_config = min_sdk_config,
             toolchain_type = toolchain_type,
@@ -618,6 +620,7 @@ def _optimized_dex_merge(
         postprocessing_output_map = None,
         startup_profile = None,
         build_metadata_output = None,
+        input_dump_output = None,
         optimizing_dexer = None,
         min_sdk_config = None,
         toolchain_type = None):
@@ -648,6 +651,10 @@ def _optimized_dex_merge(
         outputs.append(build_metadata_output)
         args.add("--build_metadata_output", build_metadata_output)
 
+    if input_dump_output:
+        outputs.append(input_dump_output)
+        args.add("--input_dump_output", input_dump_output)
+
     if postprocessing_output_map:
         param_file_args.add("--pg-map-output", postprocessing_output_map)
         outputs.append(postprocessing_output_map)