Do not use module maps if the crosstool doesn't support them when using the

legacy feature configuration.

This requires two fixes:
1. we want to mark the module_maps feature unsupported, if the toolchain itself
   doesn't provide a module map
2. no legacy feature is allowed to imply the module_maps feature

--
MOS_MIGRATED_REVID=87511295

2 files changed, 4 insertions, 1 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 0c172ef285..64bd28e237 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
@@ -667,6 +667,9 @@ public final class CcCommon {
       unsupportedFeaturesBuilder.add(CppRuleClasses.PARSE_HEADERS);
       unsupportedFeaturesBuilder.add(CppRuleClasses.PREPROCESS_HEADERS);
     }
+    if (toolchain.getCppCompilationContext().getCppModuleMap() == null) {
+      unsupportedFeaturesBuilder.add(CppRuleClasses.MODULE_MAPS);
+    }
     Set<String> unsupportedFeatures = unsupportedFeaturesBuilder.build();
     ImmutableSet.Builder<String> requestedFeatures = ImmutableSet.builder();
     for (String feature : Iterables.concat(DEFAULT_FEATURES, ruleContext.getFeatures())) {
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
index abf15df2b9..fbef38e61c 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
@@ -708,7 +708,7 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
         TextFormat.merge(""
             + "feature {"
             + "  name: 'use_module_maps'"
-            + "  implies: 'module_maps'"
+            + "  requires: { feature: 'module_maps' }"
             + "  flag_set {"
             + "    action: 'c-compile'"
             + "    action: 'c++-compile'"