8003581: UseG1GC is not properly accounted for by INCLUDE_ALTERNATE_GCS

Summary: Fix warning messages when selected garbage collectors are excluded from the minimal jvm.
Reviewed-by: dholmes, cjplummer

src/share/vm/runtime/arguments.cpp

@@ -1738,16 +1738,6 @@ bool Arguments::verify_percentage(uintx value, const char* name) {
   return false;
 }
 
-static void force_serial_gc() {
-  FLAG_SET_DEFAULT(UseSerialGC, true);
-  FLAG_SET_DEFAULT(UseParNewGC, false);
-  FLAG_SET_DEFAULT(UseConcMarkSweepGC, false);
-  FLAG_SET_DEFAULT(CMSIncrementalMode, false);  // special CMS suboption
-  FLAG_SET_DEFAULT(UseParallelGC, false);
-  FLAG_SET_DEFAULT(UseParallelOldGC, false);
-  FLAG_SET_DEFAULT(UseG1GC, false);
-}
-
 static bool verify_serial_gc_flags() {
   return (UseSerialGC &&
         !(UseParNewGC || (UseConcMarkSweepGC || CMSIncrementalMode) || UseG1GC ||
@@ -3064,6 +3054,27 @@ do {                                                            \
   }                                                             \
 } while(0)
 
+
+#define UNSUPPORTED_GC_OPTION(gc)                                     \
+do {                                                                  \
+  if (gc) {                                                           \
+    if (FLAG_IS_CMDLINE(gc)) {                                        \
+      warning(#gc " is not supported in this VM.  Using Serial GC."); \
+    }                                                                 \
+    FLAG_SET_DEFAULT(gc, false);                                      \
+  }                                                                   \
+} while(0)
+
+static void force_serial_gc() {
+  FLAG_SET_DEFAULT(UseSerialGC, true);
+  FLAG_SET_DEFAULT(CMSIncrementalMode, false);  // special CMS suboption
+  UNSUPPORTED_GC_OPTION(UseG1GC);
+  UNSUPPORTED_GC_OPTION(UseParallelGC);
+  UNSUPPORTED_GC_OPTION(UseParallelOldGC);
+  UNSUPPORTED_GC_OPTION(UseConcMarkSweepGC);
+  UNSUPPORTED_GC_OPTION(UseParNewGC);
+}
+
 // Parse entry point called from JNI_CreateJavaVM
 
 jint Arguments::parse(const JavaVMInitArgs* args) {
@@ -3179,28 +3190,15 @@ jint Arguments::parse(const JavaVMInitArgs* args) {
             hotspotrc, hotspotrc);
   }
 
-#if (defined JAVASE_EMBEDDED || defined ARM)
-  UNSUPPORTED_OPTION(UseG1GC, "G1 GC");
-#endif
-
 #ifdef _ALLBSD_SOURCE  // UseLargePages is not yet supported on BSD.
   UNSUPPORTED_OPTION(UseLargePages, "-XX:+UseLargePages");
 #endif
 
-#if !INCLUDE_ALL_GCS
-  if (UseParallelGC) {
-    warning("Parallel GC is not supported in this VM.  Using Serial GC.");
-  }
-  if (UseParallelOldGC) {
-    warning("Parallel Old GC is not supported in this VM.  Using Serial GC.");
-  }
-  if (UseConcMarkSweepGC) {
-    warning("Concurrent Mark Sweep GC is not supported in this VM.  Using Serial GC.");
-  }
-  if (UseParNewGC) {
-    warning("Par New GC is not supported in this VM.  Using Serial GC.");
-  }
-#endif // INCLUDE_ALL_GCS
+#if INCLUDE_ALL_GCS
+  #if (defined JAVASE_EMBEDDED || defined ARM)
+    UNSUPPORTED_OPTION(UseG1GC, "G1 GC");
+  #endif
+#endif
 
 #ifndef PRODUCT
   if (TraceBytecodesAt != 0) {