Replace toolchain_features with known_features and enabled_features.

BEGIN_PUBLIC
Replace toolchain_features with known_features and enabled_features.

This should allow for the deprecation of action_type_config, as `implies` there is no longer required.
END_PUBLIC

PiperOrigin-RevId: 658620044
Change-Id: Idda9bd77edad1be1fd26d5a655e3b9084d38bca8

cc/toolchains/cc_toolchain_info.bzl

@@ -191,6 +191,7 @@ ToolchainConfigInfo = provider(
     fields = {
         "label": "(Label) The label defining this provider. Place in error messages to simplify debugging",
         "features": "(Sequence[FeatureInfo]) The features available for this toolchain",
+        "enabled_features": "(Sequence[FeatureInfo]) The features That are enabled by default for this toolchain",
         "action_type_configs": "(dict[ActionTypeInfo, ActionTypeConfigInfo]) The configuration of action configs for the toolchain.",
         "args": "(Sequence[ArgsInfo]) A list of arguments to be unconditionally applied to the toolchain.",
         "files": "(dict[ActionTypeInfo, depset[File]]) Files required for the toolchain, keyed by the action type.",

cc/toolchains/impl/legacy_converter.bzl

@@ -157,7 +157,7 @@ def convert_toolchain(toolchain):
         name = "implied_by_always_enabled",
         enabled = True,
         args = ArgsListInfo(args = toolchain.args),
-        implies = depset([]),
+        implies = depset([ft for ft in toolchain.enabled_features]),
         requires_any_of = [],
         mutually_exclusive = [],
         external = False,
@@ -168,6 +168,6 @@ def convert_toolchain(toolchain):
     ]
 
     return struct(
-        features = sorted([ft for ft in features if ft != None], key = lambda ft: ft.name),
+        features = [ft for ft in features if ft != None],
         action_configs = sorted(action_configs, key = lambda ac: ac.action_name),
     )

cc/toolchains/impl/toolchain_config.bzl

@@ -51,14 +51,15 @@ cc_legacy_file_group = rule(
 
 def _cc_toolchain_config_impl(ctx):
     if ctx.attr.features:
-        fail("Features is a reserved attribute in bazel. Did you mean 'toolchain_features'")
+        fail("Features is a reserved attribute in bazel. Did you mean 'known_features' or 'enabled_features'?")
 
     if not ctx.attr._enabled[BuildSettingInfo].value and not ctx.attr.skip_experimental_flag_validation_for_test:
         fail("Rule based toolchains are experimental. To use it, please add --@rules_cc//cc/toolchains:experimental_enable_rule_based_toolchains to your bazelrc")
 
     toolchain_config = toolchain_config_info(
         label = ctx.label,
-        features = ctx.attr.toolchain_features + [ctx.attr._builtin_features],
+        known_features = ctx.attr.known_features + [ctx.attr._builtin_features],
+        enabled_features = ctx.attr.enabled_features,
         action_type_configs = ctx.attr.action_type_configs,
         args = ctx.attr.args,
     )
@@ -109,7 +110,8 @@ cc_toolchain_config = rule(
         # Attributes new to this rule.
         "action_type_configs": attr.label_list(providers = [ActionTypeConfigSetInfo]),
         "args": attr.label_list(providers = [ArgsListInfo]),
-        "toolchain_features": attr.label_list(providers = [FeatureSetInfo]),
+        "known_features": attr.label_list(providers = [FeatureSetInfo]),
+        "enabled_features": attr.label_list(providers = [FeatureSetInfo]),
         "skip_experimental_flag_validation_for_test": attr.bool(default = False),
         "_builtin_features": attr.label(default = "//cc/toolchains/features:all_builtin_features"),
         "_enabled": attr.label(default = "//cc/toolchains:experimental_enable_rule_based_toolchains"),

cc/toolchains/impl/toolchain_config_info.bzl

@@ -132,12 +132,14 @@ def _collect_files_for_action_type(atc, features, args):
 
     return depset(transitive = transitive_files)
 
-def toolchain_config_info(label, features = [], args = [], action_type_configs = [], fail = fail):
+def toolchain_config_info(label, known_features = [], enabled_features = [], args = [], action_type_configs = [], fail = fail):
     """Generates and validates a ToolchainConfigInfo from lists of labels.
 
     Args:
         label: (Label) The label to apply to the ToolchainConfigInfo
-        features: (List[Target]) A list of targets providing FeatureSetInfo
+        known_features: (List[Target]) A list of features that can be enabled.
+        enabled_features: (List[Target]) A list of features that are enabled by
+          default. Every enabled feature is implicitly also a known feature.
         args: (List[Target]) A list of targets providing ArgsListInfo
         action_type_configs: (List[Target]) A list of targets providing
           ActionTypeConfigSetInfo
@@ -145,7 +147,14 @@ def toolchain_config_info(label, features = [], args = [], action_type_configs =
     Returns:
         A validated ToolchainConfigInfo
     """
-    features = collect_features(features).to_list()
+
+    # Later features will come after earlier features on the command-line, and
+    # thus override them. Because of this, we ensure that known_features comes
+    # *after* enabled_features, so that if we do enable them, they override the
+    # default feature flags.
+    features = collect_features(enabled_features + known_features).to_list()
+    enabled_features = collect_features(enabled_features).to_list()
+
     args = collect_args_lists(args, label = label)
     action_type_configs = collect_action_type_config_sets(
         action_type_configs,
@@ -160,6 +169,7 @@ def toolchain_config_info(label, features = [], args = [], action_type_configs =
     toolchain_config = ToolchainConfigInfo(
         label = label,
         features = features,
+        enabled_features = enabled_features,
         action_type_configs = action_type_configs,
         args = args.args,
         files = files,

tests/rule_based_toolchain/subjects.bzl

@@ -220,6 +220,7 @@ _ToolchainConfigFactory = generate_factory(
     "ToolchainConfigInfo",
     dict(
         features = ProviderDepset(_FeatureFactory),
+        enabled_features = _subjects.collection,
         action_type_configs = dict_key_subject(_ActionTypeConfigFactory.factory),
         args = ProviderSequence(_ArgsFactory),
         files = dict_key_subject(_subjects.depset_file),

tests/rule_based_toolchain/toolchain_config/BUILD

@@ -48,9 +48,10 @@ util.helper_target(
     cxx_builtin_include_directories = [
         "//tests/rule_based_toolchain/testdata:directory",
     ],
+    enabled_features = [":simple_feature"],
+    known_features = [":compile_feature"],
     skip_experimental_flag_validation_for_test = True,
     sysroot = "//tests/rule_based_toolchain/testdata:directory",
-    toolchain_features = [":compile_feature"],
 )
 
 util.helper_target(

tests/rule_based_toolchain/toolchain_config/toolchain_config_test.bzl

@@ -56,7 +56,7 @@ def _empty_toolchain_valid_test(env, _targets):
 def _duplicate_feature_names_invalid_test(env, targets):
     _expect_that_toolchain(
         env,
-        features = [targets.simple_feature, targets.same_feature_name],
+        known_features = [targets.simple_feature, targets.same_feature_name],
         expr = "duplicate_feature_name",
     ).err().contains_all_of([
         "The feature name simple_feature was defined by",
@@ -67,14 +67,14 @@ def _duplicate_feature_names_invalid_test(env, targets):
     # Overriding a feature gives it the same name. Ensure this isn't blocked.
     _expect_that_toolchain(
         env,
-        features = [targets.builtin_feature, targets.overrides_feature],
+        known_features = [targets.builtin_feature, targets.overrides_feature],
         expr = "override_feature",
     ).ok()
 
 def _duplicate_action_type_invalid_test(env, targets):
     _expect_that_toolchain(
         env,
-        features = [targets.simple_feature],
+        known_features = [targets.simple_feature],
         action_type_configs = [targets.compile_config, targets.c_compile_config],
     ).err().contains_all_of([
         "The action type %s is configured by" % targets.c_compile.label,
@@ -85,14 +85,14 @@ def _duplicate_action_type_invalid_test(env, targets):
 def _action_config_implies_missing_feature_invalid_test(env, targets):
     _expect_that_toolchain(
         env,
-        features = [targets.simple_feature],
+        known_features = [targets.simple_feature],
         action_type_configs = [targets.c_compile_config],
         expr = "action_type_config_with_implies",
     ).ok()
 
     _expect_that_toolchain(
         env,
-        features = [],
+        known_features = [],
         action_type_configs = [targets.c_compile_config],
         expr = "action_type_config_missing_implies",
     ).err().contains(
@@ -103,12 +103,12 @@ def _feature_config_implies_missing_feature_invalid_test(env, targets):
     _expect_that_toolchain(
         env,
         expr = "feature_with_implies",
-        features = [targets.simple_feature, targets.implies_simple_feature],
+        known_features = [targets.simple_feature, targets.implies_simple_feature],
     ).ok()
 
     _expect_that_toolchain(
         env,
-        features = [targets.implies_simple_feature],
+        known_features = [targets.implies_simple_feature],
         expr = "feature_missing_implies",
     ).err().contains(
         "%s implies the feature %s" % (targets.implies_simple_feature.label, targets.simple_feature.label),
@@ -117,17 +117,17 @@ def _feature_config_implies_missing_feature_invalid_test(env, targets):
 def _feature_missing_requirements_invalid_test(env, targets):
     _expect_that_toolchain(
         env,
-        features = [targets.requires_any_simple_feature, targets.simple_feature],
+        known_features = [targets.requires_any_simple_feature, targets.simple_feature],
         expr = "requires_any_simple_has_simple",
     ).ok()
     _expect_that_toolchain(
         env,
-        features = [targets.requires_any_simple_feature, targets.simple_feature2],
+        known_features = [targets.requires_any_simple_feature, targets.simple_feature2],
         expr = "requires_any_simple_has_simple2",
     ).ok()
     _expect_that_toolchain(
         env,
-        features = [targets.requires_any_simple_feature],
+        known_features = [targets.requires_any_simple_feature],
         expr = "requires_any_simple_has_none",
     ).err().contains(
         "It is impossible to enable %s" % targets.requires_any_simple_feature.label,
@@ -135,19 +135,19 @@ def _feature_missing_requirements_invalid_test(env, targets):
 
     _expect_that_toolchain(
         env,
-        features = [targets.requires_all_simple_feature, targets.simple_feature, targets.simple_feature2],
+        known_features = [targets.requires_all_simple_feature, targets.simple_feature, targets.simple_feature2],
         expr = "requires_all_simple_has_both",
     ).ok()
     _expect_that_toolchain(
         env,
-        features = [targets.requires_all_simple_feature, targets.simple_feature],
+        known_features = [targets.requires_all_simple_feature, targets.simple_feature],
         expr = "requires_all_simple_has_simple",
     ).err().contains(
         "It is impossible to enable %s" % targets.requires_all_simple_feature.label,
     )
     _expect_that_toolchain(
         env,
-        features = [targets.requires_all_simple_feature, targets.simple_feature2],
+        known_features = [targets.requires_all_simple_feature, targets.simple_feature2],
         expr = "requires_all_simple_has_simple2",
     ).err().contains(
         "It is impossible to enable %s" % targets.requires_all_simple_feature.label,
@@ -157,13 +157,13 @@ def _args_missing_requirements_invalid_test(env, targets):
     _expect_that_toolchain(
         env,
         args = [targets.requires_all_simple_args],
-        features = [targets.simple_feature, targets.simple_feature2],
+        known_features = [targets.simple_feature, targets.simple_feature2],
         expr = "has_both",
     ).ok()
     _expect_that_toolchain(
         env,
         args = [targets.requires_all_simple_args],
-        features = [targets.simple_feature],
+        known_features = [targets.simple_feature],
         expr = "has_only_one",
     ).err().contains(
         "It is impossible to enable %s" % targets.requires_all_simple_args.label,
@@ -185,6 +185,16 @@ def _toolchain_collects_files_test(env, targets):
 
     legacy = convert_toolchain(tc.actual)
     env.expect.that_collection(legacy.features).contains_exactly([
+        legacy_feature(
+            name = "simple_feature",
+            enabled = False,
+            flag_sets = [legacy_flag_set(
+                actions = ["c_compile"],
+                flag_groups = [
+                    legacy_flag_group(flags = ["c_compile_args"]),
+                ],
+            )],
+        ),
         legacy_feature(
             name = "compile_feature",
             enabled = True,
@@ -198,6 +208,7 @@ def _toolchain_collects_files_test(env, targets):
         legacy_feature(
             name = "implied_by_always_enabled",
             enabled = True,
+            implies = ["simple_feature"],
             flag_sets = [legacy_flag_set(
                 actions = ["c_compile"],
                 flag_groups = [