Add tracked arena allocator

Available under -DZEND_TRACK_ARENA_ALLOC. This will use the system
allocator combined with arena checkpointing & release semantics
and allows analyzing arena usage under asan/valgrind.

I've sacrificed the duplicate arena implementation in mysqlnd, as
the integration with mysqlnd alloc is not worth the code duplication
to me.

diff --git a/Zend/zend_arena.h b/Zend/zend_arena.h
index a469616592c429a24583bdd3c1a2e591ff6a1c9b..6ecc1fc85fb4668bfd412fabd53a380be7299c0a 100644 (file)
--- a/Zend/zend_arena.h
+++ b/Zend/zend_arena.h
@@ -21,6 +21,8 @@
 
 #include "zend.h"
 
+#ifndef ZEND_TRACK_ARENA_ALLOC
+
 typedef struct _zend_arena zend_arena;
 
 struct _zend_arena {
@@ -48,8 +50,6 @@ static zend_always_inline void zend_arena_destroy(zend_arena *arena)
        } while (arena);
 }
 
-#define ZEND_ARENA_ALIGNMENT 8U
-
 static zend_always_inline void* zend_arena_alloc(zend_arena **arena_ptr, size_t size)
 {
        zend_arena *arena = *arena_ptr;
@@ -121,4 +121,104 @@ static zend_always_inline zend_bool zend_arena_contains(zend_arena *arena, void
        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)
+{
+       int overflow;
+       size_t size;
+       void *ret;
+
+       size = zend_safe_address(unit_size, count, 0, &overflow);
+       if (UNEXPECTED(overflow)) {
+               zend_error(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 zend_bool zend_arena_contains(zend_arena *arena, void *ptr)
+{
+       /* TODO: Dummy */
+       return 1;
+}
+
+#endif
+
 #endif /* _ZEND_ARENA_H_ */

diff --git a/ext/mysqlnd/mysqlnd_block_alloc.c b/ext/mysqlnd/mysqlnd_block_alloc.c
index bce28a0330c139b4d52b1df25b67592efa166912..63a48f4faadb29e5d4e004be10c4861fe6505e33 100644 (file)
--- a/ext/mysqlnd/mysqlnd_block_alloc.c
+++ b/ext/mysqlnd/mysqlnd_block_alloc.c
@@ -24,83 +24,13 @@
 #include "mysqlnd_debug.h"
 #include "mysqlnd_priv.h"
 
-
-/* {{{ mysqlnd_arena_create */
-static zend_always_inline zend_arena* mysqlnd_arena_create(size_t size)
-{
-       zend_arena *arena = (zend_arena*)mnd_emalloc(size);
-
-       arena->ptr = (char*) arena + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena));
-       arena->end = (char*) arena + size;
-       arena->prev = NULL;
-       return arena;
-}
-/* }}} */
-
-/* {{{ mysqlnd_arena_destroy */
-static zend_always_inline void mysqlnd_arena_destroy(zend_arena *arena)
-{
-       do {
-               zend_arena *prev = arena->prev;
-               mnd_efree(arena);
-               arena = prev;
-       } while (arena);
-}
-/* }}} */
-
-/* {{{ mysqlnd_arena_alloc */
-static zend_always_inline void* mysqlnd_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*)mnd_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* mysqlnd_arena_checkpoint(zend_arena *arena)
-{
-       return arena->ptr;
-}
-
-static zend_always_inline void mysqlnd_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;
-               mnd_efree(arena);
-               *arena_ptr = arena = prev;
-       }
-       ZEND_ASSERT((char*)checkpoint > (char*)arena && (char*)checkpoint <= arena->end);
-       arena->ptr = (char*)checkpoint;
-}
-
 /* {{{ mysqlnd_mempool_free_chunk */
 static void
 mysqlnd_mempool_free_chunk(MYSQLND_MEMORY_POOL * pool, void * ptr)
 {
        DBG_ENTER("mysqlnd_mempool_free_chunk");
        /* Try to back-off and guess if this is the last block allocated */
+#ifndef ZEND_TRACK_ARENA_ALLOC
        if (ptr == pool->last) {
                /*
                        This was the last allocation. Lucky us, we can free
@@ -109,6 +39,7 @@ mysqlnd_mempool_free_chunk(MYSQLND_MEMORY_POOL * pool, void * ptr)
                pool->arena->ptr = (char*)ptr;
                pool->last = NULL;
        }
+#endif
        DBG_VOID_RETURN;
 }
 /* }}} */
@@ -120,6 +51,7 @@ mysqlnd_mempool_resize_chunk(MYSQLND_MEMORY_POOL * pool, void * ptr, size_t old_
 {
        DBG_ENTER("mysqlnd_mempool_resize_chunk");
 
+#ifndef ZEND_TRACK_ARENA_ALLOC
        /* Try to back-off and guess if this is the last block allocated */
        if (ptr == pool->last
          && (ZEND_MM_ALIGNED_SIZE(size) <= ((char*)pool->arena->end - (char*)ptr))) {
@@ -128,11 +60,13 @@ mysqlnd_mempool_resize_chunk(MYSQLND_MEMORY_POOL * pool, void * ptr, size_t old_
                        a bit of memory from the pool. Next time we will return from the same ptr.
                */
                pool->arena->ptr = (char*)ptr + ZEND_MM_ALIGNED_SIZE(size);
-       } else {
-               void *new_ptr = mysqlnd_arena_alloc(&pool->arena, size);
-               memcpy(new_ptr, ptr, MIN(old_size, size));
-               pool->last = ptr = new_ptr;
+               DBG_RETURN(ptr);
        }
+#endif
+
+       void *new_ptr = zend_arena_alloc(&pool->arena, size);
+       memcpy(new_ptr, ptr, MIN(old_size, size));
+       pool->last = ptr = new_ptr;
        DBG_RETURN(ptr);
 }
 /* }}} */
@@ -145,7 +79,7 @@ mysqlnd_mempool_get_chunk(MYSQLND_MEMORY_POOL * pool, size_t size)
        void *ptr = NULL;
        DBG_ENTER("mysqlnd_mempool_get_chunk");
 
-       ptr = mysqlnd_arena_alloc(&pool->arena, size);
+       ptr = zend_arena_alloc(&pool->arena, size);
        pool->last = ptr;
 
        DBG_RETURN(ptr);
@@ -161,8 +95,8 @@ mysqlnd_mempool_create(size_t arena_size)
        MYSQLND_MEMORY_POOL * ret;
 
        DBG_ENTER("mysqlnd_mempool_create");
-       arena = mysqlnd_arena_create(MAX(arena_size, sizeof(zend_arena)));
-       ret = mysqlnd_arena_alloc(&arena, sizeof(MYSQLND_MEMORY_POOL));
+       arena = zend_arena_create(MAX(arena_size, sizeof(zend_arena)));
+       ret = zend_arena_alloc(&arena, sizeof(MYSQLND_MEMORY_POOL));
        ret->arena = arena;
        ret->last = NULL;
        ret->checkpoint = NULL;
@@ -180,7 +114,7 @@ mysqlnd_mempool_destroy(MYSQLND_MEMORY_POOL * pool)
 {
        DBG_ENTER("mysqlnd_mempool_destroy");
        /* mnd_free will reference LOCK_access and might crash, depending on the caller...*/
-       mysqlnd_arena_destroy(pool->arena);
+       zend_arena_destroy(pool->arena);
        DBG_VOID_RETURN;
 }
 /* }}} */
@@ -190,7 +124,7 @@ PHPAPI void
 mysqlnd_mempool_save_state(MYSQLND_MEMORY_POOL * pool)
 {
        DBG_ENTER("mysqlnd_mempool_save_state");
-       pool->checkpoint = mysqlnd_arena_checkpoint(pool->arena);
+       pool->checkpoint = zend_arena_checkpoint(pool->arena);
        DBG_VOID_RETURN;
 }
 /* }}} */
@@ -201,7 +135,7 @@ mysqlnd_mempool_restore_state(MYSQLND_MEMORY_POOL * pool)
 {
        DBG_ENTER("mysqlnd_mempool_restore_state");
        if (pool->checkpoint) {
-               mysqlnd_arena_release(&pool->arena, pool->checkpoint);
+               zend_arena_release(&pool->arena, pool->checkpoint);
                pool->last = NULL;
                pool->checkpoint = NULL;
        }