8011343: Add new flag for verifying the heap during startup

Perform verification during VM startup under control of new flag and within a VMOperation.

Reviewed-by: stefank, jmasa, brutisso

hotspot/src/share/vm/classfile/systemDictionary.cpp

@@ -1592,9 +1592,10 @@ Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
 // Used for assertions and verification only
 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
   #ifndef ASSERT
-  guarantee(VerifyBeforeGC   ||
-            VerifyDuringGC   ||
-            VerifyBeforeExit ||
+  guarantee(VerifyBeforeGC      ||
+            VerifyDuringGC      ||
+            VerifyBeforeExit    ||
+            VerifyDuringStartup ||
             VerifyAfterGC, "too expensive");
   #endif
   assert_locked_or_safepoint(SystemDictionary_lock);

hotspot/src/share/vm/memory/genCollectedHeap.cpp

@@ -819,12 +819,13 @@ bool GenCollectedHeap::is_in_young(oop p) {
 // Returns "TRUE" iff "p" points into the committed areas of the heap.
 bool GenCollectedHeap::is_in(const void* p) const {
   #ifndef ASSERT
-  guarantee(VerifyBeforeGC   ||
-            VerifyDuringGC   ||
-            VerifyBeforeExit ||
-            PrintAssembly    ||
-            tty->count() != 0 ||   // already printing
-            VerifyAfterGC    ||
+  guarantee(VerifyBeforeGC      ||
+            VerifyDuringGC      ||
+            VerifyBeforeExit    ||
+            VerifyDuringStartup ||
+            PrintAssembly       ||
+            tty->count() != 0   ||   // already printing
+            VerifyAfterGC       ||
     VMError::fatal_error_in_progress(), "too expensive");
 
   #endif

hotspot/src/share/vm/runtime/arguments.cpp

@@ -2006,11 +2006,12 @@ bool Arguments::check_vm_args_consistency() {
   // than just disable the lock verification. This will be fixed under
   // bug 4788986.
   if (UseConcMarkSweepGC && FLSVerifyAllHeapReferences) {
-    if (VerifyGCStartAt == 0) {
+    if (VerifyDuringStartup) {
       warning("Heap verification at start-up disabled "
               "(due to current incompatibility with FLSVerifyAllHeapReferences)");
-      VerifyGCStartAt = 1;      // Disable verification at start-up
+      VerifyDuringStartup = false; // Disable verification at start-up
     }
+
     if (VerifyBeforeExit) {
       warning("Heap verification at shutdown disabled "
               "(due to current incompatibility with FLSVerifyAllHeapReferences)");

hotspot/src/share/vm/runtime/globals.hpp

@@ -2123,6 +2123,10 @@ class CommandLineFlags {
   product(intx, PrefetchFieldsAhead, -1,                                    \
           "How many fields ahead to prefetch in oop scan (<= 0 means off)") \
                                                                             \
+  diagnostic(bool, VerifyDuringStartup, false,                              \
+          "Verify memory system before executing any Java code "            \
+          "during VM initialization")                                       \
+                                                                            \
   diagnostic(bool, VerifyBeforeExit, trueInDebug,                           \
           "Verify system before exiting")                                   \
                                                                             \

hotspot/src/share/vm/runtime/thread.cpp

@@ -3446,9 +3446,9 @@ jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
   }
 
   assert (Universe::is_fully_initialized(), "not initialized");
-  if (VerifyBeforeGC && VerifyGCStartAt == 0) {
-    Universe::heap()->prepare_for_verify();
-    Universe::verify();   // make sure we're starting with a clean slate
+  if (VerifyDuringStartup) {
+    VM_Verify verify_op(false /* silent */);   // make sure we're starting with a clean slate
+    VMThread::execute(&verify_op);
   }
 
   EXCEPTION_MARK;

hotspot/src/share/vm/runtime/vm_operations.cpp

@@ -175,7 +175,8 @@ void VM_HandleFullCodeCache::doit() {
 }
 
 void VM_Verify::doit() {
-  Universe::verify();
+  Universe::heap()->prepare_for_verify();
+  Universe::verify(_silent);
 }
 
 bool VM_PrintThreads::doit_prologue() {

hotspot/src/share/vm/runtime/vm_operations.hpp

@@ -300,9 +300,9 @@ class VM_UnlinkSymbols: public VM_Operation {
 
 class VM_Verify: public VM_Operation {
  private:
-  KlassHandle _dependee;
+  bool _silent;
  public:
-  VM_Verify() {}
+  VM_Verify(bool silent) : _silent(silent) {}
   VMOp_Type type() const { return VMOp_Verify; }
   void doit();
 };

hotspot/test/gc/TestVerifyDuringStartup.java

@@ -21,23 +21,23 @@
  * questions.
  */
 
-/* @test TestVerifyBeforeGCDuringStartup.java
+/* @test TestVerifyDuringStartup.java
  * @key gc
  * @bug 8010463
- * @summary Simple test run with -XX:+VerifyBeforeGC -XX:-UseTLAB to verify 8010463
+ * @summary Simple test run with -XX:+VerifyDuringStartup -XX:-UseTLAB to verify 8010463
  * @library /testlibrary
  */
 
 import com.oracle.java.testlibrary.OutputAnalyzer;
 import com.oracle.java.testlibrary.ProcessTools;
 
-public class TestVerifyBeforeGCDuringStartup {
+public class TestVerifyDuringStartup {
   public static void main(String args[]) throws Exception {
     ProcessBuilder pb =
       ProcessTools.createJavaProcessBuilder(System.getProperty("test.vm.opts"),
                                             "-XX:-UseTLAB",
                                             "-XX:+UnlockDiagnosticVMOptions",
-                                            "-XX:+VerifyBeforeGC", "-version");
+                                            "-XX:+VerifyDuringStartup", "-version");
     OutputAnalyzer output = new OutputAnalyzer(pb.start());
     output.shouldContain("[Verifying");
     output.shouldHaveExitValue(0);