/*

 * 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;

ReservedSpace* MetaspaceShared::_shared_rs = NULL;

// 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

//   2. vtable entry for that klass points to the jump table entries

//   3. branches to common_code with %O0/klass, %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 = 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);