v8::internal::KeyedLookupCache Class Reference

#include <heap.h>

Collaboration diagram for v8::internal::KeyedLookupCache:

Classes
struct	Key

Public Member Functions
int	Lookup (Handle< Map > map, Handle< Name > name)
void	Update (Handle< Map > map, Handle< Name > name, int field_offset)
void	Clear ()
	STATIC_ASSERT ((kEntriesPerBucket &(kEntriesPerBucket - 1))==0)
	STATIC_ASSERT (kEntriesPerBucket==-kHashMask)

Static Public Attributes
static const int	kLength = 256
static const int	kCapacityMask = kLength - 1
static const int	kMapHashShift = 5
static const int	kHashMask = -4
static const int	kEntriesPerBucket = 4
static const int	kEntryLength = 2
static const int	kMapIndex = 0
static const int	kKeyIndex = 1
static const int	kNotFound = -1

Private Member Functions
	KeyedLookupCache ()
Address	keys_address ()
Address	field_offsets_address ()
	DISALLOW_COPY_AND_ASSIGN (KeyedLookupCache)

Static Private Member Functions
static int	Hash (Handle< Map > map, Handle< Name > name)

Private Attributes
Key	keys_ [kLength]
int	field_offsets_ [kLength]

Friends
class	ExternalReference
class	Isolate

Detailed Description

Definition at line 2241 of file heap.h.

Constructor & Destructor Documentation

KeyedLookupCache()

v8::internal::KeyedLookupCache::KeyedLookupCache ( )

inlineprivate

Definition at line 2267 of file heap.h.

                     {
    for (int i = 0; i < kLength; ++i) {
      keys_[i].map = NULL;
      keys_[i].name = NULL;
      field_offsets_[i] = kNotFound;
    }
  }

References field_offsets_, keys_, kLength, kNotFound, v8::internal::KeyedLookupCache::Key::map, v8::internal::KeyedLookupCache::Key::name, and NULL.

Member Function Documentation

Clear()

void v8::internal::KeyedLookupCache::Clear

(

)

Definition at line 5962 of file heap.cc.

                             {
  for (int index = 0; index < kLength; index++) keys_[index].map = NULL;
}

References keys_, kLength, map, and NULL.

Referenced by v8::internal::Heap::CreateInitialObjects(), and v8::internal::Heap::MarkCompactPrologue().

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DISALLOW_COPY_AND_ASSIGN()

v8::internal::KeyedLookupCache::DISALLOW_COPY_AND_ASSIGN ( KeyedLookupCache  )

private

field_offsets_address()

Address v8::internal::KeyedLookupCache::field_offsets_address ( )

inlineprivate

Definition at line 2281 of file heap.h.

                                  {
    return reinterpret_cast<Address>(&field_offsets_);
  }

References field_offsets_.

Hash()

int v8::internal::KeyedLookupCache::Hash ( Handle< Map >  map, Handle< Name >  name  )

inlinestaticprivate

Definition at line 5897 of file heap.cc.

                                                             {
  DisallowHeapAllocation no_gc;
  // Uses only lower 32 bits if pointers are larger.
  uintptr_t addr_hash =
      static_cast<uint32_t>(reinterpret_cast<uintptr_t>(*map)) >> kMapHashShift;
  return static_cast<uint32_t>((addr_hash ^ name->Hash()) & kCapacityMask);
}

References kCapacityMask, kMapHashShift, and name.

Referenced by Lookup(), and Update().

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keys_address()

Address v8::internal::KeyedLookupCache::keys_address ( )

inlineprivate

Definition at line 2279 of file heap.h.

{ return reinterpret_cast<Address>(&keys_); }

References keys_.

Lookup()

int v8::internal::KeyedLookupCache::Lookup	(	Handle< Map >	map,
		Handle< Name >	name
	)

Definition at line 5906 of file heap.cc.

                                                               {
  DisallowHeapAllocation no_gc;
  int index = (Hash(map, name) & kHashMask);
  for (int i = 0; i < kEntriesPerBucket; i++) {
    Key& key = keys_[index + i];
    if ((key.map == *map) && key.name->Equals(*name)) {
      return field_offsets_[index + i];
    }
  }
  return kNotFound;
}

References v8::internal::Name::Equals(), field_offsets_, Hash(), kEntriesPerBucket, keys_, kHashMask, kNotFound, map, v8::internal::KeyedLookupCache::Key::map, name, and v8::internal::KeyedLookupCache::Key::name.

Referenced by v8::internal::RUNTIME_FUNCTION().

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STATIC_ASSERT() [1/2]

v8::internal::KeyedLookupCache::STATIC_ASSERT

(

(kEntriesPerBucket &(kEntriesPerBucket - 1))

= =0

)

STATIC_ASSERT() [2/2]

v8::internal::KeyedLookupCache::STATIC_ASSERT

(

kEntriesPerBucket

= =-kHashMask

)

Update()

void v8::internal::KeyedLookupCache::Update	(	Handle< Map >	map,
		Handle< Name >	name,
		int	field_offset
	)

Definition at line 5919 of file heap.cc.

                                                {
  DisallowHeapAllocation no_gc;
  if (!name->IsUniqueName()) {
    if (!StringTable::InternalizeStringIfExists(
             name->GetIsolate(), Handle<String>::cast(name)).ToHandle(&name)) {
      return;
    }
  }
  // This cache is cleared only between mark compact passes, so we expect the
  // cache to only contain old space names.
  DCHECK(!map->GetIsolate()->heap()->InNewSpace(*name));
 
  int index = (Hash(map, name) & kHashMask);
  // After a GC there will be free slots, so we use them in order (this may
  // help to get the most frequently used one in position 0).
  for (int i = 0; i < kEntriesPerBucket; i++) {
    Key& key = keys_[index];
    Object* free_entry_indicator = NULL;
    if (key.map == free_entry_indicator) {
      key.map = *map;
      key.name = *name;
      field_offsets_[index + i] = field_offset;
      return;
    }
  }
  // No free entry found in this bucket, so we move them all down one and
  // put the new entry at position zero.
  for (int i = kEntriesPerBucket - 1; i > 0; i--) {
    Key& key = keys_[index + i];
    Key& key2 = keys_[index + i - 1];
    key = key2;
    field_offsets_[index + i] = field_offsets_[index + i - 1];
  }
 
  // Write the new first entry.
  Key& key = keys_[index];
  key.map = *map;
  key.name = *name;
  field_offsets_[index] = field_offset;
}

References DCHECK, field_offsets_, Hash(), v8::internal::StringTable::InternalizeStringIfExists(), kEntriesPerBucket, keys_, kHashMask, map, v8::internal::KeyedLookupCache::Key::map, name, v8::internal::KeyedLookupCache::Key::name, and NULL.

Referenced by v8::internal::RUNTIME_FUNCTION().

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Friends And Related Function Documentation

ExternalReference

friend class ExternalReference

friend

Definition at line 2293 of file heap.h.

Isolate

friend class Isolate

friend

Definition at line 2294 of file heap.h.

Member Data Documentation

field_offsets_

int v8::internal::KeyedLookupCache::field_offsets_[kLength]

private

Definition at line 2291 of file heap.h.

Referenced by field_offsets_address(), KeyedLookupCache(), Lookup(), and Update().

kCapacityMask

const int v8::internal::KeyedLookupCache::kCapacityMask = kLength - 1

static

Definition at line 2253 of file heap.h.

Referenced by Hash().

kEntriesPerBucket

const int v8::internal::KeyedLookupCache::kEntriesPerBucket = 4

static

Definition at line 2256 of file heap.h.

Referenced by v8::internal::CodeStubGraphBuilder< KeyedLoadGenericStub >::BuildCodeStub(), Lookup(), and Update().

kEntryLength

const int v8::internal::KeyedLookupCache::kEntryLength = 2

static

Definition at line 2257 of file heap.h.

Referenced by v8::internal::CodeStubGraphBuilder< KeyedLoadGenericStub >::BuildCodeStub().

keys_

Key v8::internal::KeyedLookupCache::keys_[kLength]

private

Definition at line 2290 of file heap.h.

Referenced by Clear(), KeyedLookupCache(), keys_address(), Lookup(), and Update().

kHashMask

const int v8::internal::KeyedLookupCache::kHashMask = -4

static

Definition at line 2255 of file heap.h.

Referenced by Lookup(), and Update().

kKeyIndex

const int v8::internal::KeyedLookupCache::kKeyIndex = 1

static

Definition at line 2259 of file heap.h.

Referenced by v8::internal::CodeStubGraphBuilder< KeyedLoadGenericStub >::BuildCodeStub().

kLength

const int v8::internal::KeyedLookupCache::kLength = 256

static

Definition at line 2252 of file heap.h.

Referenced by Clear(), and KeyedLookupCache().

kMapHashShift

const int v8::internal::KeyedLookupCache::kMapHashShift = 5

static

Definition at line 2254 of file heap.h.

Referenced by Hash().

kMapIndex

const int v8::internal::KeyedLookupCache::kMapIndex = 0

static

Definition at line 2258 of file heap.h.

Referenced by v8::internal::CodeStubGraphBuilder< KeyedLoadGenericStub >::BuildCodeStub().

kNotFound

const int v8::internal::KeyedLookupCache::kNotFound = -1

static

Definition at line 2260 of file heap.h.

Referenced by KeyedLookupCache(), and Lookup().

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The documentation for this class was generated from the following files:

• /mnt/V8SourceCode/src/heap/heap.h
• /mnt/V8SourceCode/src/heap/heap.cc