dart::FreeListElement Class Reference

#include <freelist.h>

Classes
class	FakeInstance

Public Member Functions
FreeListElement *	next () const
uword	next_address () const
void	set_next (FreeListElement *next)
intptr_t	HeapSize ()
intptr_t	HeapSize (uword tags)

Static Public Member Functions
static FreeListElement *	AsElement (uword addr, intptr_t size)
static FreeListElement *	AsElementNew (uword addr, intptr_t size)
static void	Init ()
static intptr_t	HeaderSizeFor (intptr_t size)

Static Public Attributes
static constexpr intptr_t	kLargeHeaderSize = 3 * kWordSize

Detailed Description

Definition at line 24 of file freelist.h.

Member Function Documentation

AsElement()

FreeListElement * dart::FreeListElement::AsElement ( uword  addr, intptr_t  size  )

static

Definition at line 16 of file freelist.cc.

                                                                     {
  // Precondition: the (page containing the) header of the element is
  // writable.
  ASSERT(size >= kObjectAlignment);
  ASSERT(Utils::IsAligned(size, kObjectAlignment));
 
  FreeListElement* result = reinterpret_cast<FreeListElement*>(addr);
 
  uword tags = 0;
  tags = UntaggedObject::SizeTag::update(size, tags);
  tags = UntaggedObject::ClassIdTag::update(kFreeListElement, tags);
  ASSERT((addr & kNewObjectAlignmentOffset) == kOldObjectAlignmentOffset);
  tags = UntaggedObject::AlwaysSetBit::update(true, tags);
  tags = UntaggedObject::NotMarkedBit::update(true, tags);
  tags = UntaggedObject::OldAndNotRememberedBit::update(true, tags);
  tags = UntaggedObject::NewOrEvacuationCandidateBit::update(false, tags);
  result->tags_ = tags;
 
  if (size > UntaggedObject::SizeTag::kMaxSizeTag) {
    *result->SizeAddress() = size;
  }
  result->set_next(nullptr);
  return result;
  // Postcondition: the (page containing the) header of the element is
  // writable.
}

AsElementNew()

FreeListElement * dart::FreeListElement::AsElementNew ( uword  addr, intptr_t  size  )

static

Definition at line 43 of file freelist.cc.

                                                                        {
  ASSERT(size >= kObjectAlignment);
  ASSERT(Utils::IsAligned(size, kObjectAlignment));
 
  FreeListElement* result = reinterpret_cast<FreeListElement*>(addr);
 
  uword tags = 0;
  tags = UntaggedObject::SizeTag::update(size, tags);
  tags = UntaggedObject::ClassIdTag::update(kFreeListElement, tags);
  ASSERT((addr & kNewObjectAlignmentOffset) == kNewObjectAlignmentOffset);
  tags = UntaggedObject::AlwaysSetBit::update(true, tags);
  tags = UntaggedObject::NotMarkedBit::update(true, tags);
  tags = UntaggedObject::OldAndNotRememberedBit::update(false, tags);
  tags = UntaggedObject::NewOrEvacuationCandidateBit::update(true, tags);
  result->tags_ = tags;
 
  if (size > UntaggedObject::SizeTag::kMaxSizeTag) {
    *result->SizeAddress() = size;
  }
  result->set_next(nullptr);
  return result;
}

HeaderSizeFor()

intptr_t dart::FreeListElement::HeaderSizeFor ( intptr_t  size )

static

Definition at line 71 of file freelist.cc.

                                                     {
  if (size == 0) return 0;
  return ((size > UntaggedObject::SizeTag::kMaxSizeTag) ? 3 : 2) * kWordSize;
}

HeapSize() [1/2]

intptr_t dart::FreeListElement::HeapSize ( )

inline

Definition at line 31 of file freelist.h.

{ return HeapSize(tags_); }

HeapSize() [2/2]

intptr_t dart::FreeListElement::HeapSize ( uword  tags )

inline

Definition at line 32 of file freelist.h.

                                {
    ASSERT(UntaggedObject::ClassIdTag::decode(tags) == kFreeListElement);
    intptr_t size = UntaggedObject::SizeTag::decode(tags);
    if (size != 0) return size;
    return *SizeAddress();
  }

Init()

void dart::FreeListElement::Init ( )

static

Definition at line 66 of file freelist.cc.

                           {
  ASSERT(sizeof(FreeListElement) == kObjectAlignment);
  ASSERT(OFFSET_OF(FreeListElement, tags_) == Object::tags_offset());
}

next()

FreeListElement * dart::FreeListElement::next ( ) const

inline

Definition at line 26 of file freelist.h.

{ return next_; }

next_address()

uword dart::FreeListElement::next_address ( ) const

inline

Definition at line 27 of file freelist.h.

{ return reinterpret_cast<uword>(&next_); }

set_next()

void dart::FreeListElement::set_next ( FreeListElement *  next )

inline

Definition at line 29 of file freelist.h.

{ next_ = next; }

Member Data Documentation

kLargeHeaderSize

constexpr intptr_t dart::FreeListElement::kLargeHeaderSize = 3 * kWordSize

staticconstexpr

Definition at line 44 of file freelist.h.

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

• third_party/dart-lang/sdk/runtime/vm/heap/freelist.h
• third_party/dart-lang/sdk/runtime/vm/heap/freelist.cc