Add --extra_toolchains flag to register additional toolchain labels.

Fixes https://github.com/katre/bazel/issues/4.

Change-Id: I664aaeb0d2aa4f36ecd0f1a5f13b5d7f25dcc8d6
PiperOrigin-RevId: 162355466

1 files changed, 22 insertions, 4 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/RegisteredToolchainsFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/RegisteredToolchainsFunction.java
index e77c53d2b9..666da966c1 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/RegisteredToolchainsFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/RegisteredToolchainsFunction.java
@@ -16,10 +16,12 @@ package com.google.devtools.build.lib.skyframe;
 
 import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
+import com.google.devtools.build.lib.analysis.PlatformConfiguration;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
 import com.google.devtools.build.lib.analysis.platform.DeclaredToolchainInfo;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.rules.ExternalPackageUtil;
+import com.google.devtools.build.lib.rules.ExternalPackageUtil.ExternalPackageException;
 import com.google.devtools.build.lib.skyframe.ConfiguredTargetFunction.ConfiguredValueCreationException;
 import com.google.devtools.build.skyframe.LegacySkyKey;
 import com.google.devtools.build.skyframe.SkyFunction;
@@ -44,15 +46,22 @@ public class RegisteredToolchainsFunction implements SkyFunction {
 
     BuildConfiguration configuration = (BuildConfiguration) skyKey.argument();
 
-    // Get the registered toolchains.
-    List<Label> registeredToolchainLabels = ExternalPackageUtil.getRegisteredToolchainLabels(env);
-    if (registeredToolchainLabels == null) {
+    ImmutableList.Builder<Label> registeredToolchainLabels = new ImmutableList.Builder<>();
+
+    // Get the toolchains from the configuration.
+    PlatformConfiguration platformConfiguration =
+        configuration.getFragment(PlatformConfiguration.class);
+    registeredToolchainLabels.addAll(platformConfiguration.getExtraToolchains());
+
+    // Get the registered toolchains from the WORKSPACE.
+    registeredToolchainLabels.addAll(getWorkspaceToolchains(env));
+    if (env.valuesMissing()) {
       return null;
     }
 
     // Load the configured target for each, and get the declared toolchain providers.
     ImmutableList<DeclaredToolchainInfo> registeredToolchains =
-        configureRegisteredToolchains(env, configuration, registeredToolchainLabels);
+        configureRegisteredToolchains(env, configuration, registeredToolchainLabels.build());
     if (env.valuesMissing()) {
       return null;
     }
@@ -60,6 +69,15 @@ public class RegisteredToolchainsFunction implements SkyFunction {
     return RegisteredToolchainsValue.create(registeredToolchains);
   }
 
+  private Iterable<? extends Label> getWorkspaceToolchains(Environment env)
+      throws ExternalPackageException, InterruptedException {
+    List<Label> labels = ExternalPackageUtil.getRegisteredToolchainLabels(env);
+    if (labels == null) {
+      return ImmutableList.of();
+    }
+    return labels;
+  }
+
   private ImmutableList<DeclaredToolchainInfo> configureRegisteredToolchains(
       Environment env, BuildConfiguration configuration, List<Label> labels)
       throws InterruptedException, RegisteredToolchainsFunctionException {