1 files changed, 20 insertions, 0 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
index 583b1a112f..fa9753b0dd 100644
--- 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
@@ -493,6 +493,8 @@ public class CcToolchain implements RuleConfiguredTargetFactory {
       }
     }
 
+    reportInvalidOptions(ruleContext, toolchainInfo);
+
     CcToolchainProvider ccProvider =
         new CcToolchainProvider(
             getToolchainForSkylark(toolchainInfo),
@@ -578,6 +580,24 @@ public class CcToolchain implements RuleConfiguredTargetFactory {
     return builder.build();
   }
 
+  private void reportInvalidOptions(RuleContext ruleContext, CppToolchainInfo toolchain) {
+    CppOptions options = ruleContext.getConfiguration().getOptions().get(CppOptions.class);
+    CppConfiguration config = ruleContext.getFragment(CppConfiguration.class);
+    if (options.fissionModes.contains(config.getCompilationMode())
+        && !toolchain.supportsFission()) {
+      ruleContext.ruleWarning(
+          "Fission is not supported by this crosstool.  Please use a "
+              + "supporting crosstool to enable fission");
+    }
+    if (options.buildTestDwp
+        && !(toolchain.supportsFission() && config.fissionIsActiveForCurrentCompilationMode())) {
+      ruleContext.ruleWarning(
+          "Test dwp file requested, but Fission is not enabled.  To generate a "
+              + "dwp for the test executable, use '--fission=yes' with a toolchain that supports "
+              + "Fission to build statically.");
+    }
+  }
+
   private static String getSkylarkValueForTool(Tool tool, CppToolchainInfo cppToolchainInfo) {
     PathFragment toolPath = cppToolchainInfo.getToolPathFragment(tool);
     return toolPath != null ? toolPath.getPathString() : "";