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/*
* Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#ifndef SHARE_MEMORY_UNIVERSE_HPP
#define SHARE_MEMORY_UNIVERSE_HPP
#include "gc/shared/verifyOption.hpp"
#include "oops/array.hpp"
#include "oops/oopHandle.hpp"
#include "runtime/handles.hpp"
#include "utilities/growableArray.hpp"
// Universe is a name space holding known system classes and objects in the VM.
//
// Loaded classes are accessible through the SystemDictionary.
//
// The object heap is allocated and accessed through Universe, and various allocation
// support is provided. Allocation by the interpreter and compiled code is done inline
// and bails out to Scavenge::invoke_and_allocate.
class CollectedHeap;
class DeferredObjAllocEvent;
class OopStorage;
class ReservedHeapSpace;
// A helper class for caching a Method* when the user of the cache
// only cares about the latest version of the Method*. This cache safely
// interacts with the RedefineClasses API.
class LatestMethodCache : public CHeapObj<mtClass> {
// We save the Klass* and the idnum of Method* in order to get
// the current cached Method*.
private:
Klass* _klass;
int _method_idnum;
public:
LatestMethodCache() { _klass = NULL; _method_idnum = -1; }
~LatestMethodCache() { _klass = NULL; _method_idnum = -1; }
void init(Klass* k, Method* m);
Klass* klass() const { return _klass; }
int method_idnum() const { return _method_idnum; }
Method* get_method();
// CDS support. Replace the klass in this with the archive version
// could use this for Enhanced Class Redefinition also.
void serialize(SerializeClosure* f) {
f->do_ptr((void**)&_klass);
}
void metaspace_pointers_do(MetaspaceClosure* it);
};
class Universe: AllStatic {
// Ugh. Universe is much too friendly.
friend class MarkSweep;
friend class oopDesc;
friend class ClassLoader;
friend class SystemDictionary;
friend class ReservedHeapSpace;
friend class VMStructs;
friend class VM_PopulateDumpSharedSpace;
friend class Metaspace;
friend class MetaspaceShared;
friend class vmClasses;
friend jint universe_init();
friend void universe2_init();
friend bool universe_post_init();
friend void universe_post_module_init();
private:
// Known classes in the VM
static Klass* _typeArrayKlassObjs[T_LONG+1];
static Klass* _objectArrayKlassObj;
// Special int-Array that represents filler objects that are used by GC to overwrite
// dead objects. References to them are generally an error.
static Klass* _fillerArrayKlassObj;
// Known objects in the VM
static OopHandle _main_thread_group; // Reference to the main thread group object
static OopHandle _system_thread_group; // Reference to the system thread group object
static OopHandle _the_empty_class_array; // Canonicalized obj array of type java.lang.Class
static OopHandle _the_null_string; // A cache of "null" as a Java string
static OopHandle _the_min_jint_string; // A cache of "-2147483648" as a Java string
static OopHandle _the_null_sentinel; // A unique object pointer unused except as a sentinel for null.
// preallocated error objects (no backtrace)
static OopHandle _out_of_memory_errors;
// preallocated cause message for delayed StackOverflowError
static OopHandle _delayed_stack_overflow_error_message;
static LatestMethodCache* _finalizer_register_cache; // static method for registering finalizable objects
static LatestMethodCache* _loader_addClass_cache; // method for registering loaded classes in class loader vector
static LatestMethodCache* _throw_illegal_access_error_cache; // Unsafe.throwIllegalAccessError() method
static LatestMethodCache* _throw_no_such_method_error_cache; // Unsafe.throwNoSuchMethodError() method
static LatestMethodCache* _do_stack_walk_cache; // method for stack walker callback
static Array<int>* _the_empty_int_array; // Canonicalized int array
static Array<u2>* _the_empty_short_array; // Canonicalized short array
static Array<Klass*>* _the_empty_klass_array; // Canonicalized klass array
static Array<InstanceKlass*>* _the_empty_instance_klass_array; // Canonicalized instance klass array
static Array<Method*>* _the_empty_method_array; // Canonicalized method array
static Array<Klass*>* _the_array_interfaces_array;
// array of preallocated error objects with backtrace
static OopHandle _preallocated_out_of_memory_error_array;
// number of preallocated error objects available for use
static volatile jint _preallocated_out_of_memory_error_avail_count;
// preallocated message detail strings for error objects
static OopHandle _msg_metaspace;
static OopHandle _msg_class_metaspace;
static OopHandle _null_ptr_exception_instance; // preallocated exception object
static OopHandle _arithmetic_exception_instance; // preallocated exception object
static OopHandle _virtual_machine_error_instance; // preallocated exception object
// References waiting to be transferred to the ReferenceHandler
static OopHandle _reference_pending_list;
// The particular choice of collected heap.
static CollectedHeap* _collectedHeap;
static intptr_t _non_oop_bits;
// array of dummy objects used with +FullGCAlot
debug_only(static OopHandle _fullgc_alot_dummy_array;)
debug_only(static int _fullgc_alot_dummy_next;)
// Compiler/dispatch support
static int _base_vtable_size; // Java vtbl size of klass Object (in words)
// Initialization
static bool _bootstrapping; // true during genesis
static bool _module_initialized; // true after call_initPhase2 called
static bool _fully_initialized; // true after universe_init and initialize_vtables called
// the array of preallocated errors with backtraces
static objArrayOop preallocated_out_of_memory_errors();
static objArrayOop out_of_memory_errors();
// generate an out of memory error; if possible using an error with preallocated backtrace;
// otherwise return the given default error.
static oop gen_out_of_memory_error(oop default_err);
static OopStorage* _vm_weak;
static OopStorage* _vm_global;
static jint initialize_heap();
static void initialize_tlab();
static void initialize_basic_type_mirrors(TRAPS);
static void fixup_mirrors(TRAPS);
static void compute_base_vtable_size(); // compute vtable size of class Object
static void genesis(TRAPS); // Create the initial world
// Mirrors for primitive classes (created eagerly)
static oop check_mirror(oop m) {
assert(m != NULL, "mirror not initialized");
return m;
}
// Debugging
static int _verify_count; // number of verifies done
static long verify_flags;
static uintptr_t _verify_oop_mask;
static uintptr_t _verify_oop_bits;
// Table of primitive type mirrors, excluding T_OBJECT and T_ARRAY
// but including T_VOID, hence the index including T_VOID
static OopHandle _basic_type_mirrors[T_VOID+1];
#if INCLUDE_CDS_JAVA_HEAP
// Each slot i stores an index that can be used to restore _basic_type_mirrors[i]
// from the archive heap using HeapShared::get_root(int)
static int _archived_basic_type_mirror_indices[T_VOID+1];
#endif
public:
static void calculate_verify_data(HeapWord* low_boundary, HeapWord* high_boundary) PRODUCT_RETURN;
// Known classes in the VM
static Klass* boolArrayKlassObj() { return typeArrayKlassObj(T_BOOLEAN); }
static Klass* byteArrayKlassObj() { return typeArrayKlassObj(T_BYTE); }
static Klass* charArrayKlassObj() { return typeArrayKlassObj(T_CHAR); }
static Klass* intArrayKlassObj() { return typeArrayKlassObj(T_INT); }
static Klass* shortArrayKlassObj() { return typeArrayKlassObj(T_SHORT); }
static Klass* longArrayKlassObj() { return typeArrayKlassObj(T_LONG); }
static Klass* floatArrayKlassObj() { return typeArrayKlassObj(T_FLOAT); }
static Klass* doubleArrayKlassObj() { return typeArrayKlassObj(T_DOUBLE); }
static Klass* objectArrayKlassObj() { return _objectArrayKlassObj; }
static Klass* fillerArrayKlassObj() { return _fillerArrayKlassObj; }
static Klass* typeArrayKlassObj(BasicType t) {
assert((uint)t >= T_BOOLEAN, "range check for type: %s", type2name(t));
assert((uint)t < T_LONG+1, "range check for type: %s", type2name(t));
assert(_typeArrayKlassObjs[t] != NULL, "domain check");
return _typeArrayKlassObjs[t];
}
// Known objects in the VM
static oop int_mirror();
static oop float_mirror();
static oop double_mirror();
static oop byte_mirror();
static oop bool_mirror();
static oop char_mirror();
static oop long_mirror();
static oop short_mirror();
static oop void_mirror();
static oop java_mirror(BasicType t);
#if INCLUDE_CDS_JAVA_HEAP
static void set_archived_basic_type_mirror_index(BasicType t, int index);
static void update_archived_basic_type_mirrors();
#endif
static oop main_thread_group();
static void set_main_thread_group(oop group);
static oop system_thread_group();
static void set_system_thread_group(oop group);
static objArrayOop the_empty_class_array ();
static oop the_null_string();
static oop the_min_jint_string();
static oop null_ptr_exception_instance();
static oop arithmetic_exception_instance();
static oop virtual_machine_error_instance();
static oop vm_exception() { return virtual_machine_error_instance(); }
static Array<Klass*>* the_array_interfaces_array() { return _the_array_interfaces_array; }
static Method* finalizer_register_method() { return _finalizer_register_cache->get_method(); }
static Method* loader_addClass_method() { return _loader_addClass_cache->get_method(); }
static Method* throw_illegal_access_error() { return _throw_illegal_access_error_cache->get_method(); }
static Method* throw_no_such_method_error() { return _throw_no_such_method_error_cache->get_method(); }
static Method* do_stack_walk_method() { return _do_stack_walk_cache->get_method(); }
static oop the_null_sentinel();
static address the_null_sentinel_addr() { return (address) &_the_null_sentinel; }
// Function to initialize these
static void initialize_known_methods(TRAPS);
static void create_preallocated_out_of_memory_errors(TRAPS);
// Reference pending list manipulation. Access is protected by
// Heap_lock. The getter, setter and predicate require the caller
// owns the lock. Swap is used by parallel non-concurrent reference
// processing threads, where some higher level controller owns
// Heap_lock, so requires the lock is locked, but not necessarily by
// the current thread.
static oop reference_pending_list();
static void clear_reference_pending_list();
static bool has_reference_pending_list();
static oop swap_reference_pending_list(oop list);
static Array<int>* the_empty_int_array() { return _the_empty_int_array; }
static Array<u2>* the_empty_short_array() { return _the_empty_short_array; }
static Array<Method*>* the_empty_method_array() { return _the_empty_method_array; }
static Array<Klass*>* the_empty_klass_array() { return _the_empty_klass_array; }
static Array<InstanceKlass*>* the_empty_instance_klass_array() { return _the_empty_instance_klass_array; }
// OutOfMemoryError support. Returns an error with the required message. The returned error
// may or may not have a backtrace. If error has a backtrace then the stack trace is already
// filled in.
static oop out_of_memory_error_java_heap();
static oop out_of_memory_error_c_heap();
static oop out_of_memory_error_metaspace();
static oop out_of_memory_error_class_metaspace();
static oop out_of_memory_error_array_size();
static oop out_of_memory_error_gc_overhead_limit();
static oop out_of_memory_error_realloc_objects();
// Throw default _out_of_memory_error_retry object as it will never propagate out of the VM
static oop out_of_memory_error_retry();
static oop delayed_stack_overflow_error_message();
// If it's a certain type of OOME object
static bool is_out_of_memory_error_metaspace(oop ex_obj);
static bool is_out_of_memory_error_class_metaspace(oop ex_obj);
// The particular choice of collected heap.
static CollectedHeap* heap() { return _collectedHeap; }
DEBUG_ONLY(static bool is_gc_active();)
DEBUG_ONLY(static bool is_in_heap(const void* p);)
DEBUG_ONLY(static bool is_in_heap_or_null(const void* p) { return p == NULL || is_in_heap(p); })
// Reserve Java heap and determine CompressedOops mode
static ReservedHeapSpace reserve_heap(size_t heap_size, size_t alignment);
// Global OopStorages
static OopStorage* vm_weak();
static OopStorage* vm_global();
static void oopstorage_init();
// Testers
static bool is_bootstrapping() { return _bootstrapping; }
static bool is_module_initialized() { return _module_initialized; }
static bool is_fully_initialized() { return _fully_initialized; }
static bool on_page_boundary(void* addr);
static bool should_fill_in_stack_trace(Handle throwable);
static void check_alignment(uintx size, uintx alignment, const char* name);
// CDS support
static void serialize(SerializeClosure* f);
// Apply the closure to all klasses for basic types (classes not present in
// SystemDictionary).
static void basic_type_classes_do(KlassClosure* closure);
static void metaspace_pointers_do(MetaspaceClosure* it);
// Debugging
enum VERIFY_FLAGS {
Verify_Threads = 1,
Verify_Heap = 2,
Verify_SymbolTable = 4,
Verify_StringTable = 8,
Verify_CodeCache = 16,
Verify_SystemDictionary = 32,
Verify_ClassLoaderDataGraph = 64,
Verify_MetaspaceUtils = 128,
Verify_JNIHandles = 256,
Verify_CodeCacheOops = 512,
Verify_ResolvedMethodTable = 1024,
Verify_StringDedup = 2048,
Verify_All = -1
};
static void initialize_verify_flags();
static bool should_verify_subset(uint subset);
static void verify(VerifyOption option, const char* prefix);
static void verify(const char* prefix) {
verify(VerifyOption::Default, prefix);
}
static void verify() {
verify("");
}
static int verify_count() { return _verify_count; }
static void print_on(outputStream* st);
static void print_heap_at_SIGBREAK();
// Change the number of dummy objects kept reachable by the full gc dummy
// array; this should trigger relocation in a sliding compaction collector.
debug_only(static bool release_fullgc_alot_dummy();)
// The non-oop pattern (see compiledIC.hpp, etc)
static void* non_oop_word();
static bool contains_non_oop_word(void* p);
// Oop verification (see MacroAssembler::verify_oop)
static uintptr_t verify_oop_mask() PRODUCT_RETURN0;
static uintptr_t verify_oop_bits() PRODUCT_RETURN0;
static uintptr_t verify_mark_bits() PRODUCT_RETURN0;
static uintptr_t verify_mark_mask() PRODUCT_RETURN0;
// Compiler support
static int base_vtable_size() { return _base_vtable_size; }
};
#endif // SHARE_MEMORY_UNIVERSE_HPP
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