Re-implement cc_toolchain_alias to handle toolchain resolution.

PiperOrigin-RevId: 368833080
ptarjan · Apr 16, 2021 · db17c1e · db17c1e
1 parent 8ace6db
commit db17c1e
Show file tree

Hide file tree

Showing 2 changed files with 83 additions and 7 deletions.
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchain.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchain.java
@@ -117,9 +117,8 @@ public ConfiguredTarget create(RuleContext ruleContext)
     return ruleConfiguredTargetBuilder.build();
   }
 
-  static TemplateVariableInfo createMakeVariableProvider(
-      CcToolchainProvider toolchainProvider,
-      Location location) {
+  public static TemplateVariableInfo createMakeVariableProvider(
+      CcToolchainProvider toolchainProvider, Location location) {
 
     HashMap<String, String> makeVariables =
         new HashMap<>(toolchainProvider.getAdditionalMakeVariables());

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainAliasRule.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcToolchainAliasRule.java
@@ -14,11 +14,88 @@
 
 package com.google.devtools.build.lib.rules.cpp;
 
-import com.google.devtools.build.lib.rules.LateBoundAlias.CommonAliasRule;
+import static com.google.devtools.build.lib.packages.Attribute.attr;
+import static com.google.devtools.build.lib.packages.BuildType.LABEL;
+import static com.google.devtools.build.lib.packages.BuildType.NODEP_LABEL;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.devtools.build.lib.actions.MutableActionGraph.ActionConflictException;
+import com.google.devtools.build.lib.analysis.BaseRuleClasses;
+import com.google.devtools.build.lib.analysis.ConfiguredTarget;
+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;
+import com.google.devtools.build.lib.analysis.RuleDefinition;
+import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
+import com.google.devtools.build.lib.analysis.Runfiles;
+import com.google.devtools.build.lib.analysis.RunfilesProvider;
+import com.google.devtools.build.lib.analysis.TemplateVariableInfo;
+import com.google.devtools.build.lib.analysis.platform.ToolchainInfo;
+import com.google.devtools.build.lib.packages.RuleClass;
+import com.google.devtools.build.lib.packages.RuleClass.ToolchainTransitionMode;
 
 /** Implementation of the {@code cc_toolchain_alias} rule. */
-public class CcToolchainAliasRule extends CommonAliasRule<CppConfiguration> {
-  public CcToolchainAliasRule() {
-    super("cc_toolchain_alias", CppRuleClasses::ccToolchainAttribute, CppConfiguration.class);
+public class CcToolchainAliasRule implements RuleDefinition {
+  @Override
+  public RuleClass build(RuleClass.Builder builder, RuleDefinitionEnvironment env) {
+    return builder
+        .requiresConfigurationFragments(CppConfiguration.class)
+        .removeAttribute("licenses")
+        .removeAttribute("distribs")
+        .add(
+            attr(CcToolchain.CC_TOOLCHAIN_DEFAULT_ATTRIBUTE_NAME, LABEL)
+                .mandatoryProviders(CcToolchainProvider.PROVIDER.id())
+                .value(CppRuleClasses.ccToolchainAttribute(env)))
+        .add(
+            attr(CcToolchain.CC_TOOLCHAIN_TYPE_ATTRIBUTE_NAME, NODEP_LABEL)
+                .value(CppRuleClasses.ccToolchainTypeAttribute(env)))
+        .requiresConfigurationFragments(PlatformConfiguration.class)
+        .addRequiredToolchains(CppRuleClasses.ccToolchainTypeAttribute(env))
+        .useToolchainTransition(ToolchainTransitionMode.ENABLED)
+        .build();
+  }
+
+  @Override
+  public Metadata getMetadata() {
+    return Metadata.builder()
+        .name("cc_toolchain_alias")
+        .ancestors(BaseRuleClasses.NativeBuildRule.class)
+        .factoryClass(CcToolchainAlias.class)
+        .build();
+  }
+
+  /** Implementation of cc_toolchain_alias. */
+  public static class CcToolchainAlias implements RuleConfiguredTargetFactory {
+    @Override
+    public ConfiguredTarget create(RuleContext ruleContext)
+        throws InterruptedException, RuleErrorException, ActionConflictException {
+
+      CcToolchainProvider ccToolchainProvider =
+          CppHelper.getToolchainUsingDefaultCcToolchainAttribute(ruleContext);
+
+      TemplateVariableInfo templateVariableInfo =
+          CcToolchain.createMakeVariableProvider(
+              ccToolchainProvider, ruleContext.getRule().getLocation());
+
+      ToolchainInfo toolchain =
+          new ToolchainInfo(
+              ImmutableMap.<String, Object>builder()
+                  .put("cc", ccToolchainProvider)
+                  // Add a clear signal that this is a CcToolchainProvider, since just "cc" is
+                  // generic enough to possibly be re-used.
+                  .put("cc_provider_in_toolchain", true)
+                  .build());
+
+      return new RuleConfiguredTargetBuilder(ruleContext)
+          .addProvider(RunfilesProvider.simple(Runfiles.EMPTY))
+          .addNativeDeclaredProvider(ccToolchainProvider)
+          .addNativeDeclaredProvider(toolchain)
+          .addNativeDeclaredProvider(templateVariableInfo)
+          .setFilesToBuild(ccToolchainProvider.getAllFiles())
+          .addProvider(new MiddlemanProvider(ccToolchainProvider.getAllFilesMiddleman()))
+          .build();
+    }
   }
 }