Add host/target feature support for ThinLTO

ThinLTO isn't fully supported for host builds, in order to handle this add
support for enabling either a 'host' or 'target' feature in the configuration.
The thin_lto feature will require the new 'target' configuration.

Companion crosstool change: unknown commit.

--
MOS_MIGRATED_REVID=127350506

1 files changed, 14 insertions, 3 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java
index a4cecb798e..684ac7a062 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CcCommon.java
@@ -501,6 +501,14 @@ public final class CcCommon {
             withBaselineCoverage);
   }
 
+  private static String getHostOrNonHostFeature(RuleContext ruleContext) {
+    if (ruleContext.getConfiguration().isHostConfiguration()) {
+      return "host";
+    } else {
+      return "nonhost";
+    }
+  }
+
   /**
    * Creates the feature configuration for a given rule.
    *
@@ -530,9 +538,12 @@ public final class CcCommon {
     }
     Set<String> unsupportedFeatures = unsupportedFeaturesBuilder.build();
     ImmutableSet.Builder<String> requestedFeatures = ImmutableSet.builder();
-    for (String feature : Iterables.concat(
-        ImmutableSet.of(toolchain.getCompilationMode().toString()), DEFAULT_FEATURES,
-        ruleContext.getFeatures())) {
+    for (String feature :
+        Iterables.concat(
+            ImmutableSet.of(toolchain.getCompilationMode().toString()),
+            ImmutableSet.of(getHostOrNonHostFeature(ruleContext)),
+            DEFAULT_FEATURES,
+            ruleContext.getFeatures())) {
       if (!unsupportedFeatures.contains(feature)) {
         requestedFeatures.add(feature);
       }