Mercurial > hg > graal-compiler
diff src/share/vm/memory/metaspaceShared.cpp @ 6725:da91efe96a93
6964458: Reimplement class meta-data storage to use native memory
Summary: Remove PermGen, allocate meta-data in metaspace linked to class loaders, rewrite GC walking, rewrite and rename metadata to be C++ classes
Reviewed-by: jmasa, stefank, never, coleenp, kvn, brutisso, mgerdin, dholmes, jrose, twisti, roland
Contributed-by: jmasa <jon.masamitsu@oracle.com>, stefank <stefan.karlsson@oracle.com>, mgerdin <mikael.gerdin@oracle.com>, never <tom.rodriguez@oracle.com>
author | coleenp |
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date | Sat, 01 Sep 2012 13:25:18 -0400 |
parents | |
children | fa6e618671d7 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/memory/metaspaceShared.cpp Sat Sep 01 13:25:18 2012 -0400 @@ -0,0 +1,844 @@ +/* + * Copyright (c) 2012, 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. + * + */ + +#include "precompiled.hpp" +#include "classfile/dictionary.hpp" +#include "classfile/loaderConstraints.hpp" +#include "classfile/placeholders.hpp" +#include "classfile/symbolTable.hpp" +#include "classfile/systemDictionary.hpp" +#include "code/codeCache.hpp" +#include "memory/filemap.hpp" +#include "memory/gcLocker.hpp" +#include "memory/metaspace.hpp" +#include "memory/metaspaceShared.hpp" +#include "oops/objArrayOop.hpp" +#include "oops/oop.inline.hpp" +#include "runtime/signature.hpp" +#include "runtime/vm_operations.hpp" +#include "runtime/vmThread.hpp" +#include "utilities/hashtable.inline.hpp" + + +int MetaspaceShared::_max_alignment = 0; +int MetaspaceShared::max_alignment() { return _max_alignment; } +void MetaspaceShared::set_max_alignment(int alignment) { _max_alignment = alignment; } + +// Accessor functions to save shared space created for metadata, which has +// extra space allocated at the end for miscellaneous data and code. +ReservedSpace* MetaspaceShared::_shared_rs = NULL; +ReservedSpace* MetaspaceShared::shared_rs() { return _shared_rs; } +void MetaspaceShared::set_shared_rs(ReservedSpace* rs) { _shared_rs = rs; } + +// Read/write a data stream for restoring/preserving metadata pointers and +// miscellaneous data from/to the shared archive file. + +void MetaspaceShared::serialize(SerializeClosure* soc) { + int tag = 0; + soc->do_tag(--tag); + + assert(!UseCompressedOops, "UseCompressedOops doesn't work with shared archive"); + // Verify the sizes of various metadata in the system. + soc->do_tag(sizeof(Method)); + soc->do_tag(sizeof(ConstMethod)); + soc->do_tag(arrayOopDesc::base_offset_in_bytes(T_BYTE)); + soc->do_tag(sizeof(ConstantPool)); + soc->do_tag(sizeof(ConstantPoolCache)); + soc->do_tag(objArrayOopDesc::base_offset_in_bytes()); + soc->do_tag(typeArrayOopDesc::base_offset_in_bytes(T_BYTE)); + soc->do_tag(sizeof(Symbol)); + + // Dump/restore miscellaneous metadata. + Universe::serialize(soc, true); + soc->do_tag(--tag); + + // Dump/restore references to commonly used names and signatures. + vmSymbols::serialize(soc); + soc->do_tag(--tag); + + soc->do_tag(666); +} + + +// CDS code for dumping shared archive. + +// Global object for holding classes that have been loaded. Since this +// is run at a safepoint just before exit, this is the entire set of classes. +static GrowableArray<Klass*>* _global_klass_objects; +static void collect_classes(Klass* k) { + _global_klass_objects->append_if_missing(k); + if (k->oop_is_instance()) { + // Add in the array classes too + InstanceKlass* ik = InstanceKlass::cast(k); + ik->array_klasses_do(collect_classes); + } +} + +static void remove_unshareable_in_classes() { + for (int i = 0; i < _global_klass_objects->length(); i++) { + Klass* k = _global_klass_objects->at(i); + k->remove_unshareable_info(); + } +} + +// Walk all methods in the class list and assign a fingerprint. +// so that this part of the ConstMethod* is read only. +static void calculate_fingerprints() { + for (int i = 0; i < _global_klass_objects->length(); i++) { + Klass* k = _global_klass_objects->at(i); + if (k->oop_is_instance()) { + InstanceKlass* ik = InstanceKlass::cast(k); + for (int i = 0; i < ik->methods()->length(); i++) { + ResourceMark rm; + Method* m = ik->methods()->at(i); + (new Fingerprinter(m))->fingerprint(); + } + } + } +} + +// Patch C++ vtable pointer in metadata. + +// Klass and other metadata objects contain references to c++ vtables in the +// JVM library. +// Fix them to point to our constructed vtables. However, don't iterate +// across the space while doing this, as that causes the vtables to be +// patched, undoing our useful work. Instead, iterate to make a list, +// then use the list to do the fixing. +// +// Our constructed vtables: +// Dump time: +// 1. init_self_patching_vtbl_list: table of pointers to current virtual method addrs +// 2. generate_vtable_methods: create jump table, appended to above vtbl_list +// 3. patch_klass_vtables: for Klass list, patch the vtable entry in klass and +// associated metadata to point to jump table rather than to current vtbl +// Table layout: NOTE FIXED SIZE +// 1. vtbl pointers +// 2. #Klass X #virtual methods per Klass +// 1 entry for each, in the order: +// Klass1:method1 entry, Klass1:method2 entry, ... Klass1:method<num_virtuals> entry +// Klass2:method1 entry, Klass2:method2 entry, ... Klass2:method<num_virtuals> entry +// ... +// Klass<vtbl_list_size>:method1 entry, Klass<vtbl_list_size>:method2 entry, +// ... Klass<vtbl_list_size>:method<num_virtuals> entry +// Sample entry: (Sparc): +// save(sp, -256, sp) +// ba,pt common_code +// mov XXX, %L0 %L0 gets: Klass index <<8 + method index (note: max method index 255) +// +// Restore time: +// 1. initialize_shared_space: reserve space for table +// 2. init_self_patching_vtbl_list: update pointers to NEW virtual method addrs in text +// +// Execution time: +// First virtual method call for any object of these metadata types: +// 1. object->klass->klass_part +// 2. vtable entry for that klass_part points to the jump table entries +// 3. branches to common_code with %O0/klass_part, %L0: Klass index <<8 + method index +// 4. common_code: +// Get address of new vtbl pointer for this Klass from updated table +// Update new vtbl pointer in the Klass: future virtual calls go direct +// Jump to method, using new vtbl pointer and method index + + +static void* find_matching_vtbl_ptr(void** vtbl_list, void* new_vtable_start, void* obj) { + void* old_vtbl_ptr = *(void**)obj; + for (int i = 0; i < MetaspaceShared::vtbl_list_size; i++) { + if (vtbl_list[i] == old_vtbl_ptr) { + return (void**)new_vtable_start + i * MetaspaceShared::num_virtuals; + } + } + ShouldNotReachHere(); + return NULL; +} + +// Assumes the vtable is in first slot in object. +static void patch_klass_vtables(void** vtbl_list, void* new_vtable_start) { + int n = _global_klass_objects->length(); + for (int i = 0; i < n; i++) { + Klass* obj = _global_klass_objects->at(i); + // Note oop_is_instance() is a virtual call. After patching vtables + // all virtual calls on the dummy vtables will restore the original! + if (obj->oop_is_instance()) { + InstanceKlass* ik = InstanceKlass::cast(obj); + *(void**)ik = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, ik); + ConstantPool* cp = ik->constants(); + *(void**)cp = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, cp); + for (int j = 0; j < ik->methods()->length(); j++) { + Method* m = ik->methods()->at(j); + *(void**)m = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, m); + } + } else { + // Array klasses + Klass* k = obj; + *(void**)k = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, k); + } + } +} + +// Closure for serializing initialization data out to a data area to be +// written to the shared file. + +class WriteClosure : public SerializeClosure { +private: + intptr_t* top; + char* end; + + inline void check_space() { + if ((char*)top + sizeof(intptr_t) > end) { + report_out_of_shared_space(SharedMiscData); + } + } + +public: + WriteClosure(char* md_top, char* md_end) { + top = (intptr_t*)md_top; + end = md_end; + } + + char* get_top() { return (char*)top; } + + void do_ptr(void** p) { + check_space(); + *top = (intptr_t)*p; + ++top; + } + + void do_tag(int tag) { + check_space(); + *top = (intptr_t)tag; + ++top; + } + + void do_region(u_char* start, size_t size) { + if ((char*)top + size > end) { + report_out_of_shared_space(SharedMiscData); + } + assert((intptr_t)start % sizeof(intptr_t) == 0, "bad alignment"); + assert(size % sizeof(intptr_t) == 0, "bad size"); + do_tag((int)size); + while (size > 0) { + *top = *(intptr_t*)start; + ++top; + start += sizeof(intptr_t); + size -= sizeof(intptr_t); + } + } + + bool reading() const { return false; } +}; + + +// Populate the shared space. + +class VM_PopulateDumpSharedSpace: public VM_Operation { +private: + ClassLoaderData* _loader_data; + GrowableArray<Klass*> *_class_promote_order; + VirtualSpace _md_vs; + VirtualSpace _mc_vs; + +public: + VM_PopulateDumpSharedSpace(ClassLoaderData* loader_data, + GrowableArray<Klass*> *class_promote_order) : + _loader_data(loader_data) { + + // Split up and initialize the misc code and data spaces + ReservedSpace* shared_rs = MetaspaceShared::shared_rs(); + int metadata_size = SharedReadOnlySize+SharedReadWriteSize; + ReservedSpace shared_ro_rw = shared_rs->first_part(metadata_size); + ReservedSpace misc_section = shared_rs->last_part(metadata_size); + + // Now split into misc sections. + ReservedSpace md_rs = misc_section.first_part(SharedMiscDataSize); + ReservedSpace mc_rs = misc_section.last_part(SharedMiscDataSize); + _md_vs.initialize(md_rs, SharedMiscDataSize); + _mc_vs.initialize(mc_rs, SharedMiscCodeSize); + _class_promote_order = class_promote_order; + } + + VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; } + void doit(); // outline because gdb sucks +}; // class VM_PopulateDumpSharedSpace + + +void VM_PopulateDumpSharedSpace::doit() { + Thread* THREAD = VMThread::vm_thread(); + NOT_PRODUCT(SystemDictionary::verify();) + // The following guarantee is meant to ensure that no loader constraints + // exist yet, since the constraints table is not shared. This becomes + // more important now that we don't re-initialize vtables/itables for + // shared classes at runtime, where constraints were previously created. + guarantee(SystemDictionary::constraints()->number_of_entries() == 0, + "loader constraints are not saved"); + guarantee(SystemDictionary::placeholders()->number_of_entries() == 0, + "placeholders are not saved"); + // Revisit and implement this if we prelink method handle call sites: + guarantee(SystemDictionary::invoke_method_table() == NULL || + SystemDictionary::invoke_method_table()->number_of_entries() == 0, + "invoke method table is not saved"); + + // At this point, many classes have been loaded. + // Gather systemDictionary classes in a global array and do everything to + // that so we don't have to walk the SystemDictionary again. + _global_klass_objects = new GrowableArray<Klass*>(1000); + Universe::basic_type_classes_do(collect_classes); + SystemDictionary::classes_do(collect_classes); + + tty->print_cr("Number of classes %d", _global_klass_objects->length()); + + // Update all the fingerprints in the shared methods. + tty->print("Calculating fingerprints ... "); + calculate_fingerprints(); + tty->print_cr("done. "); + + // Remove all references outside the metadata + tty->print("Removing unshareable information ... "); + remove_unshareable_in_classes(); + tty->print_cr("done. "); + + // Set up the share data and shared code segments. + char* md_low = _md_vs.low(); + char* md_top = md_low; + char* md_end = _md_vs.high(); + char* mc_low = _mc_vs.low(); + char* mc_top = mc_low; + char* mc_end = _mc_vs.high(); + + // Reserve space for the list of Klass*s whose vtables are used + // for patching others as needed. + + void** vtbl_list = (void**)md_top; + int vtbl_list_size = MetaspaceShared::vtbl_list_size; + Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size); + + md_top += vtbl_list_size * sizeof(void*); + void* vtable = md_top; + + // Reserve space for a new dummy vtable for klass objects in the + // heap. Generate self-patching vtable entries. + + MetaspaceShared::generate_vtable_methods(vtbl_list, &vtable, + &md_top, md_end, + &mc_top, mc_end); + + // Reorder the system dictionary. (Moving the symbols affects + // how the hash table indices are calculated.) + // Not doing this either. + + SystemDictionary::reorder_dictionary(); + + NOT_PRODUCT(SystemDictionary::verify();) + + // Copy the the symbol table, and the system dictionary to the shared + // space in usable form. Copy the hastable + // buckets first [read-write], then copy the linked lists of entries + // [read-only]. + + SymbolTable::reverse(md_top); + NOT_PRODUCT(SymbolTable::verify()); + SymbolTable::copy_buckets(&md_top, md_end); + + SystemDictionary::reverse(); + SystemDictionary::copy_buckets(&md_top, md_end); + + ClassLoader::verify(); + ClassLoader::copy_package_info_buckets(&md_top, md_end); + ClassLoader::verify(); + + SymbolTable::copy_table(&md_top, md_end); + SystemDictionary::copy_table(&md_top, md_end); + ClassLoader::verify(); + ClassLoader::copy_package_info_table(&md_top, md_end); + ClassLoader::verify(); + + // Write the other data to the output array. + WriteClosure wc(md_top, md_end); + MetaspaceShared::serialize(&wc); + md_top = wc.get_top(); + + // Print shared spaces all the time + const char* fmt = "%s space: " PTR_FORMAT " out of " PTR_FORMAT " words allocated at " PTR_FORMAT "."; + Metaspace* ro_space = _loader_data->ro_metaspace(); + Metaspace* rw_space = _loader_data->rw_metaspace(); + tty->print_cr(fmt, "ro", ro_space->used_words(Metaspace::NonClassType), + ro_space->capacity_words(Metaspace::NonClassType), + ro_space->bottom()); + tty->print_cr(fmt, "rw", rw_space->used_words(Metaspace::NonClassType), + rw_space->capacity_words(Metaspace::NonClassType), + rw_space->bottom()); + tty->print_cr(fmt, "md", md_top - md_low, md_end-md_low, md_low); + tty->print_cr(fmt, "mc", mc_top - mc_low, mc_end-mc_low, mc_low); + + // Update the vtable pointers in all of the Klass objects in the + // heap. They should point to newly generated vtable. + patch_klass_vtables(vtbl_list, vtable); + + // dunno what this is for. + char* saved_vtbl = (char*)os::malloc(vtbl_list_size * sizeof(void*), mtClass); + memmove(saved_vtbl, vtbl_list, vtbl_list_size * sizeof(void*)); + memset(vtbl_list, 0, vtbl_list_size * sizeof(void*)); + + // Create and write the archive file that maps the shared spaces. + + FileMapInfo* mapinfo = new FileMapInfo(); + mapinfo->populate_header(MetaspaceShared::max_alignment()); + + // Pass 1 - update file offsets in header. + mapinfo->write_header(); + mapinfo->write_space(MetaspaceShared::ro, _loader_data->ro_metaspace(), true); + mapinfo->write_space(MetaspaceShared::rw, _loader_data->rw_metaspace(), false); + mapinfo->write_region(MetaspaceShared::md, _md_vs.low(), + pointer_delta(md_top, _md_vs.low(), sizeof(char)), + SharedMiscDataSize, + false, false); + mapinfo->write_region(MetaspaceShared::mc, _mc_vs.low(), + pointer_delta(mc_top, _mc_vs.low(), sizeof(char)), + SharedMiscCodeSize, + true, true); + + // Pass 2 - write data. + mapinfo->open_for_write(); + mapinfo->write_header(); + mapinfo->write_space(MetaspaceShared::ro, _loader_data->ro_metaspace(), true); + mapinfo->write_space(MetaspaceShared::rw, _loader_data->rw_metaspace(), false); + mapinfo->write_region(MetaspaceShared::md, _md_vs.low(), + pointer_delta(md_top, _md_vs.low(), sizeof(char)), + SharedMiscDataSize, + false, false); + mapinfo->write_region(MetaspaceShared::mc, _mc_vs.low(), + pointer_delta(mc_top, _mc_vs.low(), sizeof(char)), + SharedMiscCodeSize, + true, true); + mapinfo->close(); + + memmove(vtbl_list, saved_vtbl, vtbl_list_size * sizeof(void*)); +} + +static void link_shared_classes(Klass* obj, TRAPS) { + Klass* k = Klass::cast(obj); + if (k->oop_is_instance()) { + InstanceKlass* ik = (InstanceKlass*) k; + // Link the class to cause the bytecodes to be rewritten and the + // cpcache to be created. + if (ik->init_state() < InstanceKlass::linked) { + ik->link_class(THREAD); + guarantee(!HAS_PENDING_EXCEPTION, "exception in class rewriting"); + } + } +} + + +// Support for a simple checksum of the contents of the class list +// file to prevent trivial tampering. The algorithm matches that in +// the MakeClassList program used by the J2SE build process. +#define JSUM_SEED ((jlong)CONST64(0xcafebabebabecafe)) +static jlong +jsum(jlong start, const char *buf, const int len) +{ + jlong h = start; + char *p = (char *)buf, *e = p + len; + while (p < e) { + char c = *p++; + if (c <= ' ') { + /* Skip spaces and control characters */ + continue; + } + h = 31 * h + c; + } + return h; +} + +// Preload classes from a list, populate the shared spaces and dump to a +// file. +void MetaspaceShared::preload_and_dump(TRAPS) { + TraceTime timer("Dump Shared Spaces", TraceStartupTime); + ResourceMark rm; + + // Lock out GC - is it necessary? I don't think we care. + No_GC_Verifier no_gc; + + // Preload classes to be shared. + // Should use some os:: method rather than fopen() here. aB. + // Construct the path to the class list (in jre/lib) + // Walk up two directories from the location of the VM and + // optionally tack on "lib" (depending on platform) + char class_list_path[JVM_MAXPATHLEN]; + os::jvm_path(class_list_path, sizeof(class_list_path)); + for (int i = 0; i < 3; i++) { + char *end = strrchr(class_list_path, *os::file_separator()); + if (end != NULL) *end = '\0'; + } + int class_list_path_len = (int)strlen(class_list_path); + if (class_list_path_len >= 3) { + if (strcmp(class_list_path + class_list_path_len - 3, "lib") != 0) { + strcat(class_list_path, os::file_separator()); + strcat(class_list_path, "lib"); + } + } + strcat(class_list_path, os::file_separator()); + strcat(class_list_path, "classlist"); + + FILE* file = fopen(class_list_path, "r"); + if (file != NULL) { + jlong computed_jsum = JSUM_SEED; + jlong file_jsum = 0; + + char class_name[256]; + int class_count = 0; + GrowableArray<Klass*>* class_promote_order = new GrowableArray<Klass*>(); + + // sun.io.Converters + static const char obj_array_sig[] = "[[Ljava/lang/Object;"; + SymbolTable::new_permanent_symbol(obj_array_sig, THREAD); + + // java.util.HashMap + static const char map_entry_array_sig[] = "[Ljava/util/Map$Entry;"; + SymbolTable::new_permanent_symbol(map_entry_array_sig, THREAD); + + tty->print("Loading classes to share ... "); + while ((fgets(class_name, sizeof class_name, file)) != NULL) { + if (*class_name == '#') { + jint fsh, fsl; + if (sscanf(class_name, "# %8x%8x\n", &fsh, &fsl) == 2) { + file_jsum = ((jlong)(fsh) << 32) | (fsl & 0xffffffff); + } + + continue; + } + // Remove trailing newline + size_t name_len = strlen(class_name); + class_name[name_len-1] = '\0'; + + computed_jsum = jsum(computed_jsum, class_name, (const int)name_len - 1); + + // Got a class name - load it. + TempNewSymbol class_name_symbol = SymbolTable::new_permanent_symbol(class_name, THREAD); + guarantee(!HAS_PENDING_EXCEPTION, "Exception creating a symbol."); + Klass* klass = SystemDictionary::resolve_or_null(class_name_symbol, + THREAD); + guarantee(!HAS_PENDING_EXCEPTION, "Exception resolving a class."); + if (klass != NULL) { + if (PrintSharedSpaces && Verbose && WizardMode) { + tty->print_cr("Shared spaces preloaded: %s", class_name); + } + + + InstanceKlass* ik = InstanceKlass::cast(klass); + + // Should be class load order as per -XX:+TraceClassLoadingPreorder + class_promote_order->append(ik); + + // Link the class to cause the bytecodes to be rewritten and the + // cpcache to be created. The linking is done as soon as classes + // are loaded in order that the related data structures (klass and + // cpCache) are located together. + + if (ik->init_state() < InstanceKlass::linked) { + ik->link_class(THREAD); + guarantee(!(HAS_PENDING_EXCEPTION), "exception in class rewriting"); + } + + // TODO: Resolve klasses in constant pool + ik->constants()->resolve_class_constants(THREAD); + + class_count++; + } else { + if (PrintSharedSpaces && Verbose && WizardMode) { + tty->cr(); + tty->print_cr(" Preload failed: %s", class_name); + } + } + file_jsum = 0; // Checksum must be on last line of file + } + if (computed_jsum != file_jsum) { + tty->cr(); + tty->print_cr("Preload failed: checksum of class list was incorrect."); + exit(1); + } + + tty->print_cr("done. "); + + if (PrintSharedSpaces) { + tty->print_cr("Shared spaces: preloaded %d classes", class_count); + } + + // Rewrite and unlink classes. + tty->print("Rewriting and linking classes ... "); + + // Link any classes which got missed. (It's not quite clear why + // they got missed.) This iteration would be unsafe if we weren't + // single-threaded at this point; however we can't do it on the VM + // thread because it requires object allocation. + SystemDictionary::classes_do(link_shared_classes, CATCH); + tty->print_cr("done. "); + + // Create and dump the shared spaces. Everything so far is loaded + // with the null class loader. + ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data(); + VM_PopulateDumpSharedSpace op(loader_data, class_promote_order); + VMThread::execute(&op); + + } else { + char errmsg[JVM_MAXPATHLEN]; + os::lasterror(errmsg, JVM_MAXPATHLEN); + tty->print_cr("Loading classlist failed: %s", errmsg); + exit(1); + } + + // Since various initialization steps have been undone by this process, + // it is not reasonable to continue running a java process. + exit(0); +} + + +// Closure for serializing initialization data in from a data area +// (ptr_array) read from the shared file. + +class ReadClosure : public SerializeClosure { +private: + intptr_t** _ptr_array; + + inline intptr_t nextPtr() { + return *(*_ptr_array)++; + } + +public: + ReadClosure(intptr_t** ptr_array) { _ptr_array = ptr_array; } + + void do_ptr(void** p) { + assert(*p == NULL, "initializing previous initialized pointer."); + intptr_t obj = nextPtr(); + assert((intptr_t)obj >= 0 || (intptr_t)obj < -100, + "hit tag while initializing ptrs."); + *p = (void*)obj; + } + + void do_tag(int tag) { + int old_tag; + old_tag = (int)(intptr_t)nextPtr(); + // do_int(&old_tag); + assert(tag == old_tag, "old tag doesn't match"); + FileMapInfo::assert_mark(tag == old_tag); + } + + void do_region(u_char* start, size_t size) { + assert((intptr_t)start % sizeof(intptr_t) == 0, "bad alignment"); + assert(size % sizeof(intptr_t) == 0, "bad size"); + do_tag((int)size); + while (size > 0) { + *(intptr_t*)start = nextPtr(); + start += sizeof(intptr_t); + size -= sizeof(intptr_t); + } + } + + bool reading() const { return true; } +}; + + +// Save bounds of shared spaces mapped in. +static char* _ro_base = NULL; +static char* _rw_base = NULL; +static char* _md_base = NULL; +static char* _mc_base = NULL; + +// Return true if given address is in the mapped shared space. +bool MetaspaceShared::is_in_shared_space(const void* p) { + if (_ro_base == NULL || _rw_base == NULL) { + return false; + } else { + return ((p > _ro_base && p < (_ro_base + SharedReadOnlySize)) || + (p > _rw_base && p < (_rw_base + SharedReadWriteSize))); + } +} + +void MetaspaceShared::print_shared_spaces() { + gclog_or_tty->print_cr("Shared Spaces:"); + gclog_or_tty->print(" read-only " INTPTR_FORMAT "-" INTPTR_FORMAT, + _ro_base, _ro_base + SharedReadOnlySize); + gclog_or_tty->print(" read-write " INTPTR_FORMAT "-" INTPTR_FORMAT, + _rw_base, _rw_base + SharedReadWriteSize); + gclog_or_tty->cr(); + gclog_or_tty->print(" misc-data " INTPTR_FORMAT "-" INTPTR_FORMAT, + _md_base, _md_base + SharedMiscDataSize); + gclog_or_tty->print(" misc-code " INTPTR_FORMAT "-" INTPTR_FORMAT, + _mc_base, _mc_base + SharedMiscCodeSize); + gclog_or_tty->cr(); +} + + +// Map shared spaces at requested addresses and return if succeeded. +// Need to keep the bounds of the ro and rw space for the Metaspace::contains +// call, or is_in_shared_space. +bool MetaspaceShared::map_shared_spaces(FileMapInfo* mapinfo) { + size_t image_alignment = mapinfo->alignment(); + + // Map in the shared memory and then map the regions on top of it + ReservedSpace shared_rs = mapinfo->reserve_shared_memory(); + if (!shared_rs.is_reserved()) return false; + + // Split reserved memory into pieces (windows needs this) + ReservedSpace ro_rs = shared_rs.first_part(SharedReadOnlySize); + ReservedSpace tmp_rs1 = shared_rs.last_part(SharedReadOnlySize); + ReservedSpace rw_rs = tmp_rs1.first_part(SharedReadWriteSize); + ReservedSpace tmp_rs2 = tmp_rs1.last_part(SharedReadWriteSize); + ReservedSpace md_rs = tmp_rs2.first_part(SharedMiscDataSize); + ReservedSpace mc_rs = tmp_rs2.last_part(SharedMiscDataSize); + + // Map each shared region + if ((_ro_base = mapinfo->map_region(ro)) != NULL && + (_rw_base = mapinfo->map_region(rw)) != NULL && + (_md_base = mapinfo->map_region(md)) != NULL && + (_mc_base = mapinfo->map_region(mc)) != NULL && + (image_alignment == (size_t)max_alignment())) { + // Success (no need to do anything) + return true; + } else { + // If there was a failure in mapping any of the spaces, unmap the ones + // that succeeded + if (_ro_base != NULL) mapinfo->unmap_region(ro); + if (_rw_base != NULL) mapinfo->unmap_region(rw); + if (_md_base != NULL) mapinfo->unmap_region(md); + if (_mc_base != NULL) mapinfo->unmap_region(mc); + // Release the entire mapped region + shared_rs.release(); + // If -Xshare:on is specified, print out the error message and exit VM, + // otherwise, set UseSharedSpaces to false and continue. + if (RequireSharedSpaces) { + vm_exit_during_initialization("Unable to use shared archive.", NULL); + } else { + FLAG_SET_DEFAULT(UseSharedSpaces, false); + } + return false; + } +} + +// Read the miscellaneous data from the shared file, and +// serialize it out to its various destinations. + +void MetaspaceShared::initialize_shared_spaces() { + FileMapInfo *mapinfo = FileMapInfo::current_info(); + + char* buffer = mapinfo->region_base(md); + + // Skip over (reserve space for) a list of addresses of C++ vtables + // for Klass objects. They get filled in later. + + void** vtbl_list = (void**)buffer; + buffer += MetaspaceShared::vtbl_list_size * sizeof(void*); + Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size); + + // Skip over (reserve space for) dummy C++ vtables Klass objects. + // They are used as is. + + intptr_t vtable_size = *(intptr_t*)buffer; + buffer += sizeof(intptr_t); + buffer += vtable_size; + + // Create the symbol table using the bucket array at this spot in the + // misc data space. Since the symbol table is often modified, this + // region (of mapped pages) will be copy-on-write. + + int symbolTableLen = *(intptr_t*)buffer; + buffer += sizeof(intptr_t); + int number_of_entries = *(intptr_t*)buffer; + buffer += sizeof(intptr_t); + SymbolTable::create_table((HashtableBucket<mtSymbol>*)buffer, symbolTableLen, + number_of_entries); + buffer += symbolTableLen; + + // Create the shared dictionary using the bucket array at this spot in + // the misc data space. Since the shared dictionary table is never + // modified, this region (of mapped pages) will be (effectively, if + // not explicitly) read-only. + + int sharedDictionaryLen = *(intptr_t*)buffer; + buffer += sizeof(intptr_t); + number_of_entries = *(intptr_t*)buffer; + buffer += sizeof(intptr_t); + SystemDictionary::set_shared_dictionary((HashtableBucket<mtClass>*)buffer, + sharedDictionaryLen, + number_of_entries); + buffer += sharedDictionaryLen; + + // Create the package info table using the bucket array at this spot in + // the misc data space. Since the package info table is never + // modified, this region (of mapped pages) will be (effectively, if + // not explicitly) read-only. + + int pkgInfoLen = *(intptr_t*)buffer; + buffer += sizeof(intptr_t); + number_of_entries = *(intptr_t*)buffer; + buffer += sizeof(intptr_t); + ClassLoader::create_package_info_table((HashtableBucket<mtClass>*)buffer, pkgInfoLen, + number_of_entries); + buffer += pkgInfoLen; + ClassLoader::verify(); + + // The following data in the shared misc data region are the linked + // list elements (HashtableEntry objects) for the symbol table, string + // table, and shared dictionary. The heap objects refered to by the + // symbol table, string table, and shared dictionary are permanent and + // unmovable. Since new entries added to the string and symbol tables + // are always added at the beginning of the linked lists, THESE LINKED + // LIST ELEMENTS ARE READ-ONLY. + + int len = *(intptr_t*)buffer; // skip over symbol table entries + buffer += sizeof(intptr_t); + buffer += len; + + len = *(intptr_t*)buffer; // skip over shared dictionary entries + buffer += sizeof(intptr_t); + buffer += len; + + len = *(intptr_t*)buffer; // skip over package info table entries + buffer += sizeof(intptr_t); + buffer += len; + + len = *(intptr_t*)buffer; // skip over package info table char[] arrays. + buffer += sizeof(intptr_t); + buffer += len; + + intptr_t* array = (intptr_t*)buffer; + ReadClosure rc(&array); + serialize(&rc); + + // Close the mapinfo file + mapinfo->close(); +} + +// JVM/TI RedefineClasses() support: +bool MetaspaceShared::remap_shared_readonly_as_readwrite() { + assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); + + if (UseSharedSpaces) { + // remap the shared readonly space to shared readwrite, private + FileMapInfo* mapinfo = FileMapInfo::current_info(); + if (!mapinfo->remap_shared_readonly_as_readwrite()) { + return false; + } + } + return true; +}