8081323: ConstantPool::_resolved_references is missing in heap dump

Add resolved_references and init_lock as hidden static field in class so root is found.

Reviewed-by: hseigel, jiangli, sspitsyn

src/hotspot/share/classfile/vmSymbols.hpp

@@ -461,6 +461,8 @@
   template(getProtectionDomain_signature,             "(Ljava/security/CodeSource;)Ljava/security/ProtectionDomain;") \
   template(url_code_signer_array_void_signature,      "(Ljava/net/URL;[Ljava/security/CodeSigner;)V") \
   template(module_entry_name,                         "module_entry")                             \
+  template(resolved_references_name,                  "<resolved_references>")                    \
+  template(init_lock_name,                            "<init_lock>")                              \
                                                                                                   \
   /* name symbols needed by intrinsics */                                                         \
   VM_INTRINSICS_DO(VM_INTRINSIC_IGNORE, VM_SYMBOL_IGNORE, template, VM_SYMBOL_IGNORE, VM_ALIAS_IGNORE) \

src/hotspot/share/oops/constantPool.cpp

@@ -135,6 +135,16 @@ objArrayOop ConstantPool::resolved_references() const {
   return (objArrayOop)_cache->resolved_references();
 }
 
+// Called from outside constant pool resolution where a resolved_reference array
+// may not be present.
+objArrayOop ConstantPool::resolved_references_or_null() const {
+  if (_cache == NULL) {
+    return NULL;
+  } else {
+    return (objArrayOop)_cache->resolved_references();
+  }
+}
+
 // Create resolved_references array and mapping array for original cp indexes
 // The ldc bytecode was rewritten to have the resolved reference array index so need a way
 // to map it back for resolving and some unlikely miscellaneous uses.

src/hotspot/share/oops/constantPool.hpp

@@ -226,6 +226,7 @@ class ConstantPool : public Metadata {
 
   // resolved strings, methodHandles and callsite objects from the constant pool
   objArrayOop resolved_references()  const;
+  objArrayOop resolved_references_or_null()  const;
   // mapping resolved object array indexes to cp indexes and back.
   int object_to_cp_index(int index)         { return reference_map()->at(index); }
   int cp_to_object_index(int index);

src/hotspot/share/services/heapDumper.cpp

@@ -856,6 +856,29 @@ void DumperSupport::dump_static_fields(DumpWriter* writer, Klass* k) {
     if (fldc.access_flags().is_static()) field_count++;
   }
 
+  // Add in resolved_references which is referenced by the cpCache
+  // The resolved_references is an array per InstanceKlass holding the
+  // strings and other oops resolved from the constant pool.
+  oop resolved_references = ik->constants()->resolved_references_or_null();
+  if (resolved_references != NULL) {
+    field_count++;
+
+    // Add in the resolved_references of the used previous versions of the class
+    // in the case of RedefineClasses
+    InstanceKlass* prev = ik->previous_versions();
+    while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {
+      field_count++;
+      prev = prev->previous_versions();
+    }
+  }
+
+  // Also provide a pointer to the init_lock if present, so there aren't unreferenced int[0]
+  // arrays.
+  oop init_lock = ik->init_lock();
+  if (init_lock != NULL) {
+    field_count++;
+  }
+
   writer->write_u2(field_count);
 
   // pass 2 - dump the field descriptors and raw values
@@ -873,6 +896,29 @@ void DumperSupport::dump_static_fields(DumpWriter* writer, Klass* k) {
       dump_field_value(writer, sig->byte_at(0), addr);
     }
   }
+
+  // Add resolved_references for each class that has them
+  if (resolved_references != NULL) {
+    writer->write_symbolID(vmSymbols::resolved_references_name());  // name
+    writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
+    writer->write_objectID(resolved_references);
+
+    // Also write any previous versions
+    InstanceKlass* prev = ik->previous_versions();
+    while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {
+      writer->write_symbolID(vmSymbols::resolved_references_name());  // name
+      writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
+      writer->write_objectID(prev->constants()->resolved_references());
+      prev = prev->previous_versions();
+    }
+  }
+
+  // Add init lock to the end if the class is not yet initialized
+  if (init_lock != NULL) {
+    writer->write_symbolID(vmSymbols::init_lock_name());         // name
+    writer->write_u1(sig2tag(vmSymbols::int_array_signature())); // type
+    writer->write_objectID(init_lock);
+  }
 }
 
 // dump the raw values of the instance fields of the given object
@@ -908,7 +954,7 @@ void DumperSupport::dump_instance_field_descriptors(DumpWriter* writer, Klass* k
     if (!fld.access_flags().is_static()) {
       Symbol* sig = fld.signature();
 
-      writer->write_symbolID(fld.name());                   // name
+      writer->write_symbolID(fld.name());   // name
       writer->write_u1(sig2tag(sig));       // type
     }
   }
@@ -1822,6 +1868,8 @@ void VM_HeapDumper::doit() {
   // HPROF_GC_ROOT_JNI_GLOBAL
   JNIGlobalsDumper jni_dumper(writer());
   JNIHandles::oops_do(&jni_dumper);
+  Universe::oops_do(&jni_dumper);  // technically not jni roots, but global roots
+                                   // for things like preallocated throwable backtraces
   check_segment_length();
 
   // HPROF_GC_ROOT_STICKY_CLASS