zend_arena.h

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/*
   +----------------------------------------------------------------------+
   | Zend Engine                                                          |
   +----------------------------------------------------------------------+
   | Copyright (c) Zend Technologies Ltd. (http://www.zend.com)           |
   +----------------------------------------------------------------------+
   | This source file is subject to version 2.00 of the Zend license,     |
   | that is bundled with this package in the file LICENSE, and is        |
   | available through the world-wide-web at the following url:           |
   | http://www.zend.com/license/2_00.txt.                                |
   | If you did not receive a copy of the Zend license and are unable to  |
   | obtain it through the world-wide-web, please send a note to          |
   | license@zend.com so we can mail you a copy immediately.              |
   +----------------------------------------------------------------------+
   | Authors: Dmitry Stogov <dmitry@php.net>                              |
   +----------------------------------------------------------------------+
*/
 
#ifndef _ZEND_ARENA_H_
#define _ZEND_ARENA_H_
 
#include "zend.h"
 
#ifndef ZEND_TRACK_ARENA_ALLOC
 
typedef struct _zend_arena zend_arena;
 
struct _zend_arena {
    char        *ptr;
    char        *end;
    zend_arena  *prev;
};
 
static zend_always_inline zend_arena* zend_arena_create(size_t size)
{
    zend_arena *arena = (zend_arena*)emalloc(size);
 
    arena->ptr = (char*) arena + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena));
    arena->end = (char*) arena + size;
    arena->prev = NULL;
    return arena;
}
 
static zend_always_inline void zend_arena_destroy(zend_arena *arena)
{
    do {
        zend_arena *prev = arena->prev;
        efree(arena);
        arena = prev;
    } while (arena);
}
 
static zend_always_inline void* zend_arena_alloc(zend_arena **arena_ptr, size_t size)
{
    zend_arena *arena = *arena_ptr;
    char *ptr = arena->ptr;
 
    size = ZEND_MM_ALIGNED_SIZE(size);
 
    if (EXPECTED(size <= (size_t)(arena->end - ptr))) {
        arena->ptr = ptr + size;
    } else {
        size_t arena_size =
            UNEXPECTED((size + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena))) > (size_t)(arena->end - (char*) arena)) ?
                (size + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena))) :
                (size_t)(arena->end - (char*) arena);
        zend_arena *new_arena = (zend_arena*)emalloc(arena_size);
 
        ptr = (char*) new_arena + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena));
        new_arena->ptr = (char*) new_arena + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena)) + size;
        new_arena->end = (char*) new_arena + arena_size;
        new_arena->prev = arena;
        *arena_ptr = new_arena;
    }
 
    return (void*) ptr;
}
 
static zend_always_inline void* zend_arena_calloc(zend_arena **arena_ptr, size_t count, size_t unit_size)
{
    bool overflow;
    size_t size;
    void *ret;
 
    size = zend_safe_address(unit_size, count, 0, &overflow);
    if (UNEXPECTED(overflow)) {
        zend_error_noreturn(E_ERROR, "Possible integer overflow in zend_arena_calloc() (%zu * %zu)", unit_size, count);
    }
    ret = zend_arena_alloc(arena_ptr, size);
    memset(ret, 0, size);
    return ret;
}
 
static zend_always_inline void* zend_arena_checkpoint(zend_arena *arena)
{
    return arena->ptr;
}
 
static zend_always_inline void zend_arena_release(zend_arena **arena_ptr, void *checkpoint)
{
    zend_arena *arena = *arena_ptr;
 
    while (UNEXPECTED((char*)checkpoint > arena->end) ||
           UNEXPECTED((char*)checkpoint <= (char*)arena)) {
        zend_arena *prev = arena->prev;
        efree(arena);
        *arena_ptr = arena = prev;
    }
    ZEND_ASSERT((char*)checkpoint > (char*)arena && (char*)checkpoint <= arena->end);
    arena->ptr = (char*)checkpoint;
}
 
static zend_always_inline bool zend_arena_contains(zend_arena *arena, void *ptr)
{
    while (arena) {
        if ((char*)ptr > (char*)arena && (char*)ptr <= arena->ptr) {
            return 1;
        }
        arena = arena->prev;
    }
    return 0;
}
 
#else
 
/* Use normal allocations and keep track of them for mass-freeing.
 * This is intended for use with asan/valgrind. */
 
typedef struct _zend_arena zend_arena;
 
struct _zend_arena {
    void **ptr;
    void **end;
    struct _zend_arena *prev;
    void *ptrs[0];
};
 
#define ZEND_TRACKED_ARENA_SIZE 1000
 
static zend_always_inline zend_arena *zend_arena_create(size_t _size)
{
    zend_arena *arena = (zend_arena*) emalloc(
        sizeof(zend_arena) + sizeof(void *) * ZEND_TRACKED_ARENA_SIZE);
    arena->ptr = &arena->ptrs[0];
    arena->end = &arena->ptrs[ZEND_TRACKED_ARENA_SIZE];
    arena->prev = NULL;
    return arena;
}
 
static zend_always_inline void zend_arena_destroy(zend_arena *arena)
{
    do {
        zend_arena *prev = arena->prev;
        void **ptr;
        for (ptr = arena->ptrs; ptr < arena->ptr; ptr++) {
            efree(*ptr);
        }
        efree(arena);
        arena = prev;
    } while (arena);
}
 
static zend_always_inline void *zend_arena_alloc(zend_arena **arena_ptr, size_t size)
{
    zend_arena *arena = *arena_ptr;
    if (arena->ptr == arena->end) {
        *arena_ptr = zend_arena_create(0);
        (*arena_ptr)->prev = arena;
        arena = *arena_ptr;
    }
 
    return *arena->ptr++ = emalloc(size);
}
 
static zend_always_inline void* zend_arena_calloc(zend_arena **arena_ptr, size_t count, size_t unit_size)
{
    bool overflow;
    size_t size;
    void *ret;
 
    size = zend_safe_address(unit_size, count, 0, &overflow);
    if (UNEXPECTED(overflow)) {
        zend_error_noreturn(E_ERROR, "Possible integer overflow in zend_arena_calloc() (%zu * %zu)", unit_size, count);
    }
    ret = zend_arena_alloc(arena_ptr, size);
    memset(ret, 0, size);
    return ret;
}
 
static zend_always_inline void* zend_arena_checkpoint(zend_arena *arena)
{
    return arena->ptr;
}
 
static zend_always_inline void zend_arena_release(zend_arena **arena_ptr, void *checkpoint)
{
    while (1) {
        zend_arena *arena = *arena_ptr;
        zend_arena *prev = arena->prev;
        while (1) {
            if (arena->ptr == (void **) checkpoint) {
                return;
            }
            if (arena->ptr == arena->ptrs) {
                break;
            }
            arena->ptr--;
            efree(*arena->ptr);
        }
        efree(arena);
        *arena_ptr = prev;
        ZEND_ASSERT(*arena_ptr);
    }
}
 
static zend_always_inline bool zend_arena_contains(zend_arena *arena, void *ptr)
{
    /* TODO: Dummy */
    return 1;
}
 
#endif
 
#endif /* _ZEND_ARENA_H_ */