pm_arena.h File Reference

(eb04ab9117336f2b3613244cfe8a528c52faf6d6)

A bump allocator for the prism parser. More...

#include "prism/defines.h"
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

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Data Structures
struct	pm_arena_block
	A single block of memory in the arena. More...
struct	pm_arena_t
	A bump allocator. More...

Typedefs
typedef struct pm_arena_block	pm_arena_block_t
	A single block of memory in the arena.

Functions
void	pm_arena_reserve (pm_arena_t *arena, size_t capacity)
	Ensure the arena has at least capacity bytes available in its current block, allocating a new block if necessary.
void *	pm_arena_alloc_slow (pm_arena_t *arena, size_t size)
	Slow path for pm_arena_alloc: allocate a new block and return a pointer to the first size bytes.
static PRISM_FORCE_INLINE void *	pm_arena_alloc (pm_arena_t *arena, size_t size, size_t alignment)
	Allocate memory from the arena.
static void *	pm_arena_zalloc (pm_arena_t *arena, size_t size, size_t alignment)
	Allocate zero-initialized memory from the arena.
static void *	pm_arena_memdup (pm_arena_t *arena, const void *src, size_t size, size_t alignment)
	Allocate memory from the arena and copy the given data into it.
PRISM_EXPORTED_FUNCTION void	pm_arena_free (pm_arena_t *arena)
	Free all blocks in the arena.

Detailed Description

A bump allocator for the prism parser.

Definition in file pm_arena.h.

Typedef Documentation

pm_arena_block_t

typedef struct pm_arena_block pm_arena_block_t

A single block of memory in the arena.

Blocks are linked via prev pointers so they can be freed by walking the chain.

Function Documentation

pm_arena_alloc()

static PRISM_FORCE_INLINE void * pm_arena_alloc ( pm_arena_t *  arena, size_t  size, size_t  alignment  )

static

Allocate memory from the arena.

The returned memory is NOT zeroed. This function is infallible — it aborts on allocation failure.

The fast path (bump pointer within the current block) is inlined at each call site. The slow path (new block allocation) is out-of-line.

Parameters

arena	The arena to allocate from.
size	The number of bytes to allocate.
alignment	The required alignment (must be a power of 2).

Returns

A pointer to the allocated memory.

Definition at line 80 of file pm_arena.h.

Referenced by pm_arena_memdup(), pm_arena_zalloc(), pm_constant_id_list_append(), pm_constant_pool_init(), pm_diagnostic_list_append_format(), pm_line_offset_list_append_slow(), pm_line_offset_list_init(), and pm_parser::pm_parser_init().

pm_arena_alloc_slow()

void * pm_arena_alloc_slow	(	pm_arena_t *	arena,
		size_t	size
	)

Slow path for pm_arena_alloc: allocate a new block and return a pointer to the first size bytes.

Do not call directly — use pm_arena_alloc instead.

Parameters

arena	The arena to allocate from.
size	The number of bytes to allocate.

Returns

A pointer to the allocated memory.

Called when the current block has insufficient space.

Definition at line 74 of file pm_arena.c.

Referenced by pm_arena_alloc().

pm_arena_free()

PRISM_EXPORTED_FUNCTION void pm_arena_free

(

pm_arena_t *

arena

)

Free all blocks in the arena.

After this call, all pointers returned by pm_arena_alloc and pm_arena_zalloc are invalid.

Parameters

arena

The arena to free.

Definition at line 84 of file pm_arena.c.

pm_arena_memdup()

static void * pm_arena_memdup ( pm_arena_t *  arena, const void *  src, size_t  size, size_t  alignment  )

inlinestatic

Allocate memory from the arena and copy the given data into it.

This is a convenience wrapper around pm_arena_alloc + memcpy.

Parameters

arena	The arena to allocate from.
src	The source data to copy.
size	The number of bytes to allocate and copy.
alignment	The required alignment (must be a power of 2).

Returns

A pointer to the allocated copy.

Definition at line 121 of file pm_arena.h.

pm_arena_reserve()

void pm_arena_reserve	(	pm_arena_t *	arena,
		size_t	capacity
	)

Ensure the arena has at least capacity bytes available in its current block, allocating a new block if necessary.

This allows callers to pre-size the arena to avoid repeated small block allocations.

Parameters

arena	The arena to pre-size.
capacity	The minimum number of bytes to ensure are available.

This allows callers to pre-size the arena to avoid repeated small block allocations.

Definition at line 63 of file pm_arena.c.

pm_arena_zalloc()

static void * pm_arena_zalloc ( pm_arena_t *  arena, size_t  size, size_t  alignment  )

inlinestatic

Allocate zero-initialized memory from the arena.

This function is infallible — it aborts on allocation failure.

Parameters

arena	The arena to allocate from.
size	The number of bytes to allocate.
alignment	The required alignment (must be a power of 2).

Returns

A pointer to the allocated, zero-initialized memory.

Definition at line 104 of file pm_arena.h.

Referenced by pm_constant_id_list_init_capacity(), pm_constant_pool_init(), pm_diagnostic_list_append(), and pm_diagnostic_list_append_format().