llvm::BumpPtrAllocator Class Reference

BumpPtrAllocator - This allocator is useful for containers that need very simple memory allocation strategies. More...

#include <Allocator.h>

List of all members.

Public Member Functions
	BumpPtrAllocator (size_t size=4096, size_t threshold=4096, SlabAllocator &allocator=DefaultSlabAllocator)
	~BumpPtrAllocator ()
void	Reset ()
	Reset - Deallocate all but the current slab and reset the current pointer to the beginning of it, freeing all memory allocated so far.
void *	Allocate (size_t Size, size_t Alignment)
	Allocate - Allocate space at the specified alignment.
template<typename T >
T *	Allocate ()
	Allocate space, but do not construct, one object.
template<typename T >
T *	Allocate (size_t Num)
	Allocate space for an array of objects.
template<typename T >
T *	Allocate (size_t Num, size_t Alignment)
	Allocate space for a specific count of elements and with a specified alignment.
void	Deallocate (const void *)
unsigned	GetNumSlabs () const
void	PrintStats () const
size_t	getTotalMemory () const
	Compute the total physical memory allocated by this allocator.
Private Member Functions
	BumpPtrAllocator (const BumpPtrAllocator &)
void	operator= (const BumpPtrAllocator &)
void	StartNewSlab ()
	StartNewSlab - Allocate a new slab and move the bump pointers over into the new slab.
void	DeallocateSlabs (MemSlab *Slab)
	DeallocateSlabs - Deallocate all memory slabs after and including this one.
Static Private Member Functions
static char *	AlignPtr (char *Ptr, size_t Alignment)
	AlignPtr - Align Ptr to Alignment bytes, rounding up.
Private Attributes
size_t	SlabSize
	SlabSize - Allocate data into slabs of this size unless we get an allocation above SizeThreshold.
size_t	SizeThreshold
	SizeThreshold - For any allocation larger than this threshold, we should allocate a separate slab.
SlabAllocator &	Allocator
	Allocator - The underlying allocator we use to get slabs of memory.
MemSlab *	CurSlab
	CurSlab - The slab that we are currently allocating into.
char *	CurPtr
	CurPtr - The current pointer into the current slab.
char *	End
	End - The end of the current slab.
size_t	BytesAllocated
	BytesAllocated - This field tracks how many bytes we've allocated, so that we can compute how much space was wasted.
Static Private Attributes
static MallocSlabAllocator	DefaultSlabAllocator
Friends
class	SpecificBumpPtrAllocator

---

Detailed Description

BumpPtrAllocator - This allocator is useful for containers that need very simple memory allocation strategies.

In particular, this just keeps allocating memory, and never deletes it until the entire block is dead. This makes allocation speedy, but must only be used when the trade-off is ok.

---

Constructor & Destructor Documentation

llvm::BumpPtrAllocator::BumpPtrAllocator

(

const BumpPtrAllocator &

)

[private]

llvm::BumpPtrAllocator::BumpPtrAllocator	(	size_t	size = 4096,
		size_t	threshold = 4096,
		SlabAllocator &	allocator = DefaultSlabAllocator
	)

llvm::BumpPtrAllocator::~BumpPtrAllocator

(

)

---

Member Function Documentation

char * llvm::BumpPtrAllocator::AlignPtr	(	char *	Ptr,
		size_t	Alignment
	)			[static, private]

AlignPtr - Align Ptr to Alignment bytes, rounding up.

Alignment should be a power of two. This method rounds up, so AlignPtr(7, 4) == 8 and AlignPtr(8, 4) == 8.

template<typename T >

T* llvm::BumpPtrAllocator::Allocate	(	size_t	Num,
		size_t	Alignment
	)			[inline]

Allocate space for a specific count of elements and with a specified alignment.

template<typename T >

T* llvm::BumpPtrAllocator::Allocate

(

size_t

Num

)

[inline]

Allocate space for an array of objects.

This does not construct the objects though.

template<typename T >

T* llvm::BumpPtrAllocator::Allocate

(

)

[inline]

Allocate space, but do not construct, one object.

void * llvm::BumpPtrAllocator::Allocate	(	size_t	Size,
		size_t	Alignment
	)

Allocate - Allocate space at the specified alignment.

void llvm::BumpPtrAllocator::Deallocate

(

const void *

)

[inline]

void llvm::BumpPtrAllocator::DeallocateSlabs

(

MemSlab *

Slab

)

[private]

DeallocateSlabs - Deallocate all memory slabs after and including this one.

unsigned llvm::BumpPtrAllocator::GetNumSlabs

(

)

const

size_t llvm::BumpPtrAllocator::getTotalMemory

(

)

const

Compute the total physical memory allocated by this allocator.

void llvm::BumpPtrAllocator::operator=

(

const BumpPtrAllocator &

)

[private]

void llvm::BumpPtrAllocator::PrintStats

(

)

const

void llvm::BumpPtrAllocator::Reset

(

)

Reset - Deallocate all but the current slab and reset the current pointer to the beginning of it, freeing all memory allocated so far.

void llvm::BumpPtrAllocator::StartNewSlab

(

)

[private]

StartNewSlab - Allocate a new slab and move the bump pointers over into the new slab.

Modifies CurPtr and End.

---

Friends And Related Function Documentation

friend class SpecificBumpPtrAllocator [friend]

---

Member Data Documentation

SlabAllocator& llvm::BumpPtrAllocator::Allocator [private]

Allocator - The underlying allocator we use to get slabs of memory.

This defaults to MallocSlabAllocator, which wraps malloc, but it could be changed to use a custom allocator.

size_t llvm::BumpPtrAllocator::BytesAllocated [private]

BytesAllocated - This field tracks how many bytes we've allocated, so that we can compute how much space was wasted.

char* llvm::BumpPtrAllocator::CurPtr [private]

CurPtr - The current pointer into the current slab.

This points to the next free byte in the slab.

MemSlab* llvm::BumpPtrAllocator::CurSlab [private]

CurSlab - The slab that we are currently allocating into.

MallocSlabAllocator llvm::BumpPtrAllocator::DefaultSlabAllocator [static, private]

Initial value:

  MallocSlabAllocator()

char* llvm::BumpPtrAllocator::End [private]

End - The end of the current slab.

size_t llvm::BumpPtrAllocator::SizeThreshold [private]

SizeThreshold - For any allocation larger than this threshold, we should allocate a separate slab.

size_t llvm::BumpPtrAllocator::SlabSize [private]

SlabSize - Allocate data into slabs of this size unless we get an allocation above SizeThreshold.

---

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

• Allocator.h
• Allocator.cpp