Add a mechanism for configuration fragments to add arbitrary rules to the defaults package.

--
MOS_MIGRATED_REVID=91956723

3 files changed, 30 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildOptions.java b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildOptions.java
index 8b44f65470..cee3ceb0e1 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildOptions.java
@@ -156,6 +156,15 @@ public final class BuildOptions implements Cloneable, Serializable {
     return result.build();
   }
 
+  ImmutableList<String> getDefaultsRules() {
+    ImmutableList.Builder<String> result = ImmutableList.builder();
+    for (FragmentOptions fragment : fragmentOptionsMap.values()) {
+      result.addAll(fragment.getDefaultsRules());
+    }
+
+    return result.build();
+  }
+
   /**
    * The cache key for the options collection. Recomputes cache key every time it's called.
    */
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/DefaultsPackage.java b/src/main/java/com/google/devtools/build/lib/analysis/config/DefaultsPackage.java
index 7d92bcedd7..e04633011f 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/DefaultsPackage.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/DefaultsPackage.java
@@ -15,6 +15,7 @@
 package com.google.devtools.build.lib.analysis.config;
 
 import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.syntax.Label;
@@ -93,9 +94,11 @@ public final class DefaultsPackage {
    * The map from entries to their values.
    */
   private ImmutableMap<String, ImmutableSet<Label>> values;
+  private ImmutableList<String> rules;
 
   private DefaultsPackage(BuildOptions buildOptions) {
     values = buildOptions.getDefaultsLabels();
+    rules = buildOptions.getDefaultsRules();
   }
 
   private String labelsToString(Set<Label> labels) {
@@ -122,6 +125,11 @@ public final class DefaultsPackage {
           .append("          srcs = [")
           .append(labelsToString(entry.getValue())).append("])\n");
     }
+
+    for (String rule : rules) {
+      result.append(rule).append("\n");
+    }
+
     return result.toString();
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/FragmentOptions.java b/src/main/java/com/google/devtools/build/lib/analysis/config/FragmentOptions.java
index ce4b2d2689..c7b8c47206 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/FragmentOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/FragmentOptions.java
@@ -57,6 +57,19 @@ public abstract class FragmentOptions extends OptionsBase implements Cloneable,
   }
 
   /**
+   * Returns the extra rules contributed to the default package by this fragment.
+   *
+   * <p>The return value should be a list of strings, which are merged into the BUILD files of the
+   * defaults package.
+   *
+   * <p><strong>WARNING;</strong> this method should only be used when absolutely necessary. Always
+   * prefer {@code getDefaultsLabels()} to this.
+   */
+  public ImmutableList<String> getDefaultsRules() {
+    return ImmutableList.of();
+  }
+
+  /**
    * Returns a list of potential split configuration transitions for this fragment. Split
    * configurations usually need to be explicitly enabled by passing in an option.
    */