class PermanentGenerationSpec;

class CompactingPermGenGen: public OneContigSpaceCardGeneration {

friend class VMStructs;

// Abstractly, this is a subtype that gets access to protected fields.

friend class CompactingPermGen;

private:

// Shared spaces

PermanentGenerationSpec* _spec;

size_t _shared_space_size;

VirtualSpace _ro_vs;

VirtualSpace _rw_vs;

VirtualSpace _md_vs;

VirtualSpace _mc_vs;

BlockOffsetSharedArray* _ro_bts;

BlockOffsetSharedArray* _rw_bts;

OffsetTableContigSpace* _ro_space;

OffsetTableContigSpace* _rw_space;

// With shared spaces there is a dicotomy in the use of the

// _virtual_space of the generation. There is a portion of the

// _virtual_space that is used for the unshared part of the

// permanent generation and a portion that is reserved for the shared part.

// The _reserved field in the generation represents both the

// unshared and shared parts of the generation. The _reserved

// variable is initialized for only the unshared part but is

// later extended to include the shared part during initialization

// if shared spaces are being used.

// The reserved size for the _virtual_space for CompactingPermGenGen

// is the size of the space for the permanent generation including the

// the shared spaces. This can be seen by the use of MaxPermSize

// in the allocation of PermanentGenerationSpec. The space for the

// shared spaces is committed separately (???).

// In general at initialization only a part of the

// space for the unshared part of the permanent generation is

// committed and more is committed as the permanent generation is

// grown. In growing the permanent generation the capacity() and

// max_capacity() of the generation are used. For the permanent

// generation (implemented with a CompactingPermGenGen) the capacity()

// is taken from the capacity of the space (_the_space variable used for the

// unshared part of the generation) and the max_capacity() is based

// on the size of the _reserved variable (which includes the size of the

// shared spaces) minus the size of the shared spaces.

// These values are redundant, but are called out separately to avoid

// going through heap/space/gen pointers for performance.

static HeapWord* unshared_bottom;

static HeapWord* unshared_end;

static HeapWord* shared_bottom;

static HeapWord* readonly_bottom;

static HeapWord* readonly_end;

static HeapWord* readwrite_bottom;

static HeapWord* readwrite_end;

static HeapWord* miscdata_bottom;

static HeapWord* miscdata_end;

static HeapWord* misccode_bottom;

static HeapWord* misccode_end;

static HeapWord* shared_end;

// List of klassOops whose vtbl entries are used to patch others.

static void** _vtbl_list;

// Performance Counters

GenerationCounters* _gen_counters;

CSpaceCounters* _space_counters;

void initialize_performance_counters();

public:

enum {

vtbl_list_size = 16, // number of entries in the shared space vtable list.

num_virtuals = 200 // number of virtual methods in Klass (or

// subclass) objects, or greater.

};

enum {

ro = 0, // read-only shared space in the heap

rw = 1, // read-write shared space in the heap

md = 2, // miscellaneous data for initializing tables, etc.

mc = 3, // miscellaneous code - vtable replacement.

n_regions = 4

};

CompactingPermGenGen(ReservedSpace rs, ReservedSpace shared_rs,

size_t initial_byte_size, int level, GenRemSet* remset,

ContiguousSpace* space,

PermanentGenerationSpec* perm_spec);

const char* name() const {

return "compacting perm gen";

}

const char* short_name() const {

return "Perm";

}

// Return the maximum capacity for the object space. This

// explicitly does not include the shared spaces.

size_t max_capacity() const;

void update_counters();

void compute_new_size() {

assert(false, "Should not call this -- handled at PermGen level.");

}

bool must_be_youngest() const { return false; }

bool must_be_oldest() const { return false; }

OffsetTableContigSpace* ro_space() const { return _ro_space; }

OffsetTableContigSpace* rw_space() const { return _rw_space; }

VirtualSpace* md_space() { return &_md_vs; }

VirtualSpace* mc_space() { return &_mc_vs; }

ContiguousSpace* unshared_space() const { return _the_space; }

static bool inline is_shared(const oopDesc* p) {

return (HeapWord*)p >= shared_bottom && (HeapWord*)p < shared_end;

}

// RedefineClasses note: this tester is used to check residence of

// the specified oop in the shared readonly space and not whether

// the oop is readonly.

static bool inline is_shared_readonly(const oopDesc* p) {

return (HeapWord*)p >= readonly_bottom && (HeapWord*)p < readonly_end;

}

// RedefineClasses note: this tester is used to check residence of

// the specified oop in the shared readwrite space and not whether

// the oop is readwrite.

static bool inline is_shared_readwrite(const oopDesc* p) {

return (HeapWord*)p >= readwrite_bottom && (HeapWord*)p < readwrite_end;

}

bool is_in_unshared(const void* p) const {

return OneContigSpaceCardGeneration::is_in(p);

}

bool is_in_shared(const void* p) const {

return p >= shared_bottom && p < shared_end;

}

inline bool is_in(const void* p) const {

return is_in_unshared(p) || is_in_shared(p);

}

inline PermanentGenerationSpec* spec() const { return _spec; }

inline void set_spec(PermanentGenerationSpec* spec) { _spec = spec; }

void pre_adjust_pointers();

void adjust_pointers();

void space_iterate(SpaceClosure* blk, bool usedOnly = false);

void print_on(outputStream* st) const;

void younger_refs_iterate(OopsInGenClosure* blk);

void compact();

void post_compact();

size_t contiguous_available() const;

void clear_remembered_set();

void invalidate_remembered_set();

inline bool block_is_obj(const HeapWord* addr) const {

if (addr < the_space()->top()) return true;

else if (addr < the_space()->end()) return false;

else if (addr < ro_space()->top()) return true;

else if (addr < ro_space()->end()) return false;

else if (addr < rw_space()->top()) return true;

else return false;

}

inline size_t block_size(const HeapWord* addr) const {

if (addr < the_space()->top()) {

return oop(addr)->size();

}

else if (addr < the_space()->end()) {

assert(addr == the_space()->top(), "non-block head arg to block_size");

return the_space()->end() - the_space()->top();

}

else if (addr < ro_space()->top()) {

return oop(addr)->size();

}

else if (addr < ro_space()->end()) {

assert(addr == ro_space()->top(), "non-block head arg to block_size");

return ro_space()->end() - ro_space()->top();

}

else if (addr < rw_space()->top()) {

return oop(addr)->size();

}

else {

assert(addr == rw_space()->top(), "non-block head arg to block_size");

return rw_space()->end() - rw_space()->top();

}

}

static void generate_vtable_methods(void** vtbl_list,

void** vtable,

char** md_top, char* md_end,

char** mc_top, char* mc_end);

void verify(bool allow_dirty);

// Serialization

static void initialize_oops() KERNEL_RETURN;

static void serialize_oops(SerializeOopClosure* soc);

void serialize_bts(SerializeOopClosure* soc);

// Initiate dumping of shared file.

static jint dump_shared(GrowableArray<oop>* class_promote_order, TRAPS);

// JVM/TI RedefineClasses() support:

// Remap the shared readonly space to shared readwrite, private if

// sharing is enabled. Simply returns true if sharing is not enabled

// or if the remapping has already been done by a prior call.

static bool remap_shared_readonly_as_readwrite();

};