Add incompatible flag to enable cc rules to use toolchain resolution.

New flag: --incompatible_enable_cc_toolchain_resolution

This deprecates and replaces the previous flag, --enabled_toolchain_types.

Part of #7260.

RELNOTES[INC]: Toolchain resolution for cc rules is now enabled via an
incompatible flag, --incompatible_enable_cc_toolchain_resolution. The previous
flag, --enabled_toolchain_types, is deprecated and will be removed.

PiperOrigin-RevId: 231277726

src/main/java/com/google/devtools/build/lib/analysis/PlatformOptions.java

@@ -131,16 +131,18 @@ public class PlatformOptions extends FragmentOptions {
   public boolean toolchainResolutionDebug;
 
   @Option(
-    name = "enabled_toolchain_types",
-    defaultValue = "",
-    converter = LabelListConverter.class,
-    documentationCategory = OptionDocumentationCategory.TOOLCHAIN,
-    effectTags = {OptionEffectTag.LOADING_AND_ANALYSIS},
-    help =
-        "Enable toolchain resolution for the given toolchain type, if the rules used support that. "
-            + "This does not directly change the core Blaze machinery, but is a signal to "
-            + "participating rule implementations that toolchain resolution should be used."
-  )
+      name = "enabled_toolchain_types",
+      defaultValue = "",
+      converter = LabelListConverter.class,
+      documentationCategory = OptionDocumentationCategory.TOOLCHAIN,
+      effectTags = {OptionEffectTag.LOADING_AND_ANALYSIS},
+      deprecationWarning =
+          "Use --incompatible_enable_cc_toolchain_resolution to enable toolchain for cc rules. "
+              + "Other rules will define separate flags as needed.",
+      help =
+          "Enable toolchain resolution for the given toolchain type, if the rules used support "
+              + "that. This does not directly change the core Blaze machinery, but is a signal to "
+              + "participating rule implementations that toolchain resolution should be used.")
   public List<Label> enabledToolchainTypes;
 
   @Option(

src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchain.java

@@ -13,13 +13,11 @@
 // limitations under the License.
 package com.google.devtools.build.lib.rules.cpp;
 
-import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.actions.MutableActionGraph.ActionConflictException;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
 import com.google.devtools.build.lib.analysis.LicensesProvider;
 import com.google.devtools.build.lib.analysis.MiddlemanProvider;
-import com.google.devtools.build.lib.analysis.PlatformConfiguration;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTargetFactory;
 import com.google.devtools.build.lib.analysis.RuleContext;
@@ -57,10 +55,7 @@ public ConfiguredTarget create(RuleContext ruleContext)
       ruleConfiguredTargetBuilder.add(LicensesProvider.class, attributes.getLicensesProvider());
     }
 
-    PlatformConfiguration platformConfig =
-        Preconditions.checkNotNull(ruleContext.getFragment(PlatformConfiguration.class));
-    if (!platformConfig.isToolchainTypeEnabled(
-        CppHelper.getToolchainTypeFromRuleClass(ruleContext))) {
+    if (!CppHelper.useToolchainResolution(ruleContext)) {
       // This is not a platforms-backed build, let's provide CcToolchainAttributesProvider
       // and have cc_toolchain_suite select one of its toolchains and create CcToolchainProvider
       // from its attributes.

src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainSuite.java

@@ -14,12 +14,10 @@
 package com.google.devtools.build.lib.rules.cpp;
 
 
-import com.google.common.base.Preconditions;
 import com.google.devtools.build.lib.actions.MutableActionGraph.ActionConflictException;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
 import com.google.devtools.build.lib.analysis.LicensesProvider;
 import com.google.devtools.build.lib.analysis.MiddlemanProvider;
-import com.google.devtools.build.lib.analysis.PlatformConfiguration;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTargetFactory;
 import com.google.devtools.build.lib.analysis.RuleContext;
@@ -66,10 +64,8 @@ public ConfiguredTarget create(RuleContext ruleContext)
     }
     Label selectedCcToolchain = toolchains.get(key);
     CcToolchainProvider ccToolchainProvider;
-    PlatformConfiguration platformConfig =
-        Preconditions.checkNotNull(ruleContext.getFragment(PlatformConfiguration.class));
-    if (platformConfig.isToolchainTypeEnabled(
-        CppHelper.getToolchainTypeFromRuleClass(ruleContext))) {
+
+    if (CppHelper.useToolchainResolution(ruleContext)) {
       // This is a platforms build (and the user requested to build this suite explicitly).
       // Cc_toolchains provide CcToolchainInfo already. Let's select the CcToolchainProvider from
       // toolchains and provide it here as well.

src/main/java/com/google/devtools/build/lib/rules/cpp/CppHelper.java

@@ -106,17 +106,6 @@ public static TransitiveInfoCollection mallocForTarget(RuleContext ruleContext)
     return mallocForTarget(ruleContext, "malloc");
   }
 
-  /**
-   * Returns true if this target should obtain c++ make variables from the toolchain instead of from
-   * the configuration.
-   */
-  public static boolean shouldUseToolchainForMakeVariables(RuleContext ruleContext) {
-    Label toolchainType = getToolchainTypeFromRuleClass(ruleContext);
-    return ruleContext
-        .getFragment(PlatformConfiguration.class)
-        .isToolchainTypeEnabled(toolchainType);
-  }
-
   /**
    * Expands Make variables in a list of string and tokenizes the result. If the package feature
    * no_copts_tokenization is set, tokenize only items consisting of a single make variable.
@@ -346,10 +335,7 @@ public static CcToolchainProvider getToolchain(
       RuleContext ruleContext, TransitiveInfoCollection dep) {
 
     Label toolchainType = getToolchainTypeFromRuleClass(ruleContext);
-    if (toolchainType != null
-        && ruleContext
-            .getFragment(PlatformConfiguration.class)
-            .isToolchainTypeEnabled(toolchainType)) {
+    if (toolchainType != null && useToolchainResolution(ruleContext)) {
       return getToolchainFromPlatformConstraints(ruleContext, toolchainType);
     }
     return getToolchainFromCrosstoolTop(ruleContext, dep);
@@ -866,4 +852,19 @@ public static void checkProtoLibrariesInDeps(RuleContext ruleContext,
       }
     }
   }
+
+  static boolean useToolchainResolution(RuleContext ruleContext) {
+    CppOptions cppOptions =
+        Preconditions.checkNotNull(
+            ruleContext.getConfiguration().getOptions().get(CppOptions.class));
+
+    if (cppOptions.enableCcToolchainResolution) {
+      return true;
+    }
+
+    // TODO(https://github.com/bazelbuild/bazel/issues/7260): Remove this and the flag.
+    PlatformConfiguration platformConfig =
+        Preconditions.checkNotNull(ruleContext.getFragment(PlatformConfiguration.class));
+    return platformConfig.isToolchainTypeEnabled(getToolchainTypeFromRuleClass(ruleContext));
+  }
 }

src/main/java/com/google/devtools/build/lib/rules/cpp/CppOptions.java

@@ -845,6 +845,18 @@ public Label getFdoPrefetchHintsLabel() {
   // TODO(b/122328491): Document migration steps. See #7036.
   public boolean disableLegacyCcProvider;
 
+  @Option(
+      name = "incompatible_enable_cc_toolchain_resolution",
+      defaultValue = "false",
+      documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
+      effectTags = {OptionEffectTag.LOADING_AND_ANALYSIS},
+      metadataTags = {
+        OptionMetadataTag.INCOMPATIBLE_CHANGE,
+        OptionMetadataTag.TRIGGERED_BY_ALL_INCOMPATIBLE_CHANGES
+      },
+      help = "If true, cc rules use toolchain resolution to find the cc_toolchain.")
+  public boolean enableCcToolchainResolution;
+
   @Override
   public FragmentOptions getHost() {
     CppOptions host = (CppOptions) getDefault();
@@ -896,6 +908,7 @@ public FragmentOptions getHost() {
     host.disableLegacyCcProvider = disableLegacyCcProvider;
     host.removeCpuCompilerCcToolchainAttributes = removeCpuCompilerCcToolchainAttributes;
     host.disableLegacyCrosstoolFields = disableLegacyCrosstoolFields;
+    host.enableCcToolchainResolution = enableCcToolchainResolution;
     return host;
   }
 

src/test/java/com/google/devtools/build/lib/rules/ToolchainTypeTest.java

@@ -70,9 +70,7 @@ public void testCcTargetsDependOnCcToolchainAutomatically() throws Exception {
         ")");
 
     useConfiguration(
-        "--enabled_toolchain_types="
-            + TestConstants.TOOLS_REPOSITORY
-            + "//tools/cpp:toolchain_type",
+        "--incompatible_enable_cc_toolchain_resolution",
         "--experimental_platforms=//a:mock-platform",
         "--extra_toolchains=//a:toolchain_b");
 

src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainSelectionTest.java

@@ -49,7 +49,7 @@ public void testResolvedCcToolchain() throws Exception {
     String crosstool = analysisMock.ccSupport().readCrosstoolFile();
     getAnalysisMock().ccSupport().setupCrosstoolWithRelease(mockToolsConfig, crosstool);
     useConfiguration(
-        "--enabled_toolchain_types=" + CPP_TOOLCHAIN_TYPE,
+        "--incompatible_enable_cc_toolchain_resolution",
         "--experimental_platforms=//mock_platform:mock-piii-platform",
         "--extra_toolchains=//mock_platform:toolchain_cc-compiler-piii");
     ConfiguredTarget target =
@@ -70,7 +70,7 @@ public void testToolchainSelectionWithPlatforms() throws Exception {
     String crosstool = analysisMock.ccSupport().readCrosstoolFile();
     getAnalysisMock().ccSupport().setupCrosstoolWithRelease(mockToolsConfig, crosstool);
     useConfiguration(
-        "--enabled_toolchain_types=" + CPP_TOOLCHAIN_TYPE,
+        "--incompatible_enable_cc_toolchain_resolution",
         "--experimental_platforms=//mock_platform:mock-piii-platform",
         "--extra_toolchains=//mock_platform:toolchain_cc-compiler-piii");
     ConfiguredTarget target =
@@ -110,7 +110,7 @@ public void testIncompleteCcToolchain() throws Exception {
         "filegroup(name = 'dummy_filegroup')");
 
     useConfiguration(
-        "--enabled_toolchain_types=" + CPP_TOOLCHAIN_TYPE,
+        "--incompatible_enable_cc_toolchain_resolution",
         "--experimental_platforms=//mock_platform:mock-piii-platform",
         "--extra_toolchains=//incomplete_toolchain:incomplete_toolchain_cc-compiler-piii");
 
@@ -129,7 +129,7 @@ public void testToolPaths() throws Exception {
     getAnalysisMock().ccSupport().setupCrosstoolWithRelease(mockToolsConfig, crosstoolWithPiiiLd);
 
     useConfiguration(
-        "--enabled_toolchain_types=" + CPP_TOOLCHAIN_TYPE,
+        "--incompatible_enable_cc_toolchain_resolution",
         "--experimental_platforms=//mock_platform:mock-piii-platform",
         "--extra_toolchains=//mock_platform:toolchain_cc-compiler-piii");
     ConfiguredTarget target =

src/test/java/com/google/devtools/build/lib/rules/cpp/CcToolchainTest.java

@@ -48,8 +48,6 @@
  */
 @RunWith(JUnit4.class)
 public class CcToolchainTest extends BuildViewTestCase {
-  private static final String CPP_TOOLCHAIN_TYPE =
-      TestConstants.TOOLS_REPOSITORY + "//tools/cpp:toolchain_type";
 
   @Test
   public void testFilesToBuild() throws Exception {
@@ -635,7 +633,7 @@ public void testInlineCtoolchain_withToolchainResolution() throws Exception {
             .setAbiVersion("orange")
             .buildPartial());
 
-    useConfiguration("--enabled_toolchain_types=" + CPP_TOOLCHAIN_TYPE);
+    useConfiguration("--incompatible_enable_cc_toolchain_resolution");
 
     ConfiguredTarget target = getConfiguredTarget("//a:b");
     CcToolchainProvider toolchainProvider =