Add a dedicated exec group (cpp_dwp) for CcGenerateDwp actions of cc_binary and cc_test targets

This change introduces a new `cpp_dwp` exec group for the `CcGenerateDwp` action (which assembles DWARF object (`.dwo`) files into a DWARF package (`.dwp`) file) that is created when Fission is enabled. This allows users to configure execution properties specifically for the dwp generation step using, e.g., `exec_properties = {"cpp_dwp.mem": "..."}`. This complements the existing `cpp_link` exec group (memory requirements of `CcGenerateDwp` tend to increase as the number of dependencies increases, similar to linking).

This change is backwards-compatible because previously, the only way to add exec properties to `CcGenerateDwp` actions was with an unqualified property name (e.g. `{"mem": "..."}`), and that will continue working (but now may be overridden with a `cpp_dwp.*` property).

Rules other than `cc_binary` and `cc_test` may create `CcGenerateDwp` actions via calling the `create_debug_packager_actions` function in `cc_debug_helper.bzl`, but the actions will only have a non-default exec group if a `dwp_exec_group` argument is specified in the call to `create_debug_packager_actions`.

PiperOrigin-RevId: 927158851
Change-Id: Idb57839404bd48b22b663a4dc9ced2b05352b5fc

Author: Googler

cc/common/cc_debug_helper.bzl

@@ -31,7 +31,8 @@ def create_debug_packager_actions(
         feature_configuration,
         linking_mode,
         use_pic = True,
-        lto_artifacts = []):
+        lto_artifacts = [],
+        dwp_exec_group = None):
     """Creates intermediate and final dwp creation action(s)
 
     Args:
@@ -44,6 +45,7 @@ def create_debug_packager_actions(
         linking_mode: (str) See cc_helper.bzl%linker_mode
         use_pic: (bool)
         lto_artifacts: ([CcLtoBackendArtifacts])
+        dwp_exec_group: (str) the exec group to use for the final dwp action
     """
     dwo_files = _collect_transitive_dwo_artifacts(
         cc_compilation_outputs,
@@ -97,6 +99,7 @@ def create_debug_packager_actions(
         arguments = [packager["arguments"]],
         inputs = packager["inputs"],
         outputs = packager["outputs"],
+        exec_group = dwp_exec_group,
     )
 
 def _collect_transitive_dwo_artifacts(cc_compilation_outputs, cc_debug_context, linking_mode, use_pic, lto_backend_artifacts):

cc/private/rules_impl/cc_binary.bzl

@@ -59,6 +59,7 @@ be <code>main</code>.
     },
     fragments = ["cpp"] + semantics.additional_fragments(),
     exec_groups = {
+        "cpp_dwp": exec_group(toolchains = use_cc_toolchain()),
         "cpp_link": exec_group(toolchains = use_cc_toolchain()),
     } | semantics.extra_exec_groups,
     toolchains = use_cc_toolchain() +

cc/private/rules_impl/cc_binary_impl.bzl

@@ -717,6 +717,7 @@ def cc_binary_impl(ctx, additional_linkopts, force_linkstatic = False):
         linking_mode = linking_mode,
         use_pic = use_pic,
         lto_artifacts = cc_linking_outputs_binary.all_lto_artifacts(),
+        dwp_exec_group = "cpp_dwp",
     )
     explicit_dwp_file = dwp_file
     if not cc_helper.should_create_per_object_debug_info(feature_configuration, cpp_config):

cc/private/rules_impl/cc_test.bzl

@@ -109,6 +109,7 @@ attributes common to all test rules (*_test)</a>.</p>
     },
     fragments = ["cpp", "coverage"] + semantics.additional_fragments(),
     exec_groups = {
+        "cpp_dwp": exec_group(toolchains = use_cc_toolchain()),
         "cpp_link": exec_group(toolchains = use_cc_toolchain()),
         # testing.ExecutionInfo defaults to an exec_group of "test".
         "test": exec_group(toolchains = [config_common.toolchain_type(_CC_TEST_TOOLCHAIN_TYPE, mandatory = False)]),