--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nspr/lib/ds/plarena.h	Mon Jul 28 10:47:06 2014 +0200
@@ -0,0 +1,253 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef plarena_h___
+#define plarena_h___
+/*
+ * Lifetime-based fast allocation, inspired by much prior art, including
+ * "Fast Allocation and Deallocation of Memory Based on Object Lifetimes"
+ * David R. Hanson, Software -- Practice and Experience, Vol. 20(1).
+ *
+ * Also supports LIFO allocation (PL_ARENA_MARK/PL_ARENA_RELEASE).
+ */
+#include "prtypes.h"
+#include "plarenas.h"
+
+PR_BEGIN_EXTERN_C
+
+typedef struct PLArena          PLArena;
+
+struct PLArena {
+    PLArena     *next;          /* next arena for this lifetime */
+    PRUword     base;           /* aligned base address, follows this header */
+    PRUword     limit;          /* one beyond last byte in arena */
+    PRUword     avail;          /* points to next available byte */
+};
+
+#ifdef PL_ARENAMETER
+typedef struct PLArenaStats PLArenaStats;
+
+struct PLArenaStats {
+    PLArenaStats  *next;        /* next in arenaStats list */
+    char          *name;        /* name for debugging */
+    PRUint32      narenas;      /* number of arenas in pool */
+    PRUint32      nallocs;      /* number of PL_ARENA_ALLOCATE() calls */
+    PRUint32      nreclaims;    /* number of reclaims from freeArenas */
+    PRUint32      nmallocs;     /* number of malloc() calls */
+    PRUint32      ndeallocs;    /* number of lifetime deallocations */
+    PRUint32      ngrows;       /* number of PL_ARENA_GROW() calls */
+    PRUint32      ninplace;     /* number of in-place growths */
+    PRUint32      nreleases;    /* number of PL_ARENA_RELEASE() calls */
+    PRUint32      nfastrels;    /* number of "fast path" releases */
+    PRUint32      nbytes;       /* total bytes allocated */
+    PRUint32      maxalloc;     /* maximum allocation size in bytes */
+    PRFloat64     variance;     /* size variance accumulator */
+};
+#endif
+
+struct PLArenaPool {
+    PLArena     first;          /* first arena in pool list */
+    PLArena     *current;       /* arena from which to allocate space */
+    PRUint32    arenasize;      /* net exact size of a new arena */
+    PRUword     mask;           /* alignment mask (power-of-2 - 1) */
+#ifdef PL_ARENAMETER
+    PLArenaStats stats;
+#endif
+};
+
+/*
+ * WARNING: The PL_MAKE_MEM_ macros are for internal use by NSPR. Do NOT use
+ * them in your code.
+ *
+ * NOTE: Valgrind support to be added.
+ *
+ * The PL_MAKE_MEM_ macros are modeled after the MOZ_MAKE_MEM_ macros in
+ * Mozilla's mfbt/MemoryChecking.h. Only AddressSanitizer is supported now.
+ *
+ * Provides a common interface to the ASan (AddressSanitizer) and Valgrind
+ * functions used to mark memory in certain ways. In detail, the following
+ * three macros are provided:
+ *
+ *   PL_MAKE_MEM_NOACCESS  - Mark memory as unsafe to access (e.g. freed)
+ *   PL_MAKE_MEM_UNDEFINED - Mark memory as accessible, with content undefined
+ *   PL_MAKE_MEM_DEFINED - Mark memory as accessible, with content defined
+ *
+ * With Valgrind in use, these directly map to the three respective Valgrind
+ * macros. With ASan in use, the NOACCESS macro maps to poisoning the memory,
+ * while the UNDEFINED/DEFINED macros unpoison memory.
+ *
+ * With no memory checker available, all macros expand to the empty statement.
+ */
+
+/* WARNING: PL_SANITIZE_ADDRESS is for internal use by this header. Do NOT
+ * define or test this macro in your code.
+ */
+#if defined(__has_feature)
+#if __has_feature(address_sanitizer)
+#define PL_SANITIZE_ADDRESS 1
+#endif
+#elif defined(__SANITIZE_ADDRESS__)
+#define PL_SANITIZE_ADDRESS 1
+#endif
+
+#if defined(PL_SANITIZE_ADDRESS)
+
+/* These definitions are usually provided through the
+ * sanitizer/asan_interface.h header installed by ASan.
+ * See https://code.google.com/p/address-sanitizer/wiki/ManualPoisoning
+ */
+
+void __asan_poison_memory_region(void const volatile *addr, size_t size);
+void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
+
+#define PL_MAKE_MEM_NOACCESS(addr, size) \
+    __asan_poison_memory_region((addr), (size))
+
+#define PL_MAKE_MEM_UNDEFINED(addr, size) \
+    __asan_unpoison_memory_region((addr), (size))
+
+#define PL_MAKE_MEM_DEFINED(addr, size) \
+    __asan_unpoison_memory_region((addr), (size))
+
+#else
+
+#define PL_MAKE_MEM_NOACCESS(addr, size)
+#define PL_MAKE_MEM_UNDEFINED(addr, size)
+#define PL_MAKE_MEM_DEFINED(addr, size)
+
+#endif
+
+/*
+ * If the including .c file uses only one power-of-2 alignment, it may define
+ * PL_ARENA_CONST_ALIGN_MASK to the alignment mask and save a few instructions
+ * per ALLOCATE and GROW.
+ */
+#ifdef PL_ARENA_CONST_ALIGN_MASK
+#define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + PL_ARENA_CONST_ALIGN_MASK) \
+                                & ~PL_ARENA_CONST_ALIGN_MASK)
+
+#define PL_INIT_ARENA_POOL(pool, name, size) \
+        PL_InitArenaPool(pool, name, size, PL_ARENA_CONST_ALIGN_MASK + 1)
+#else
+#define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + (pool)->mask) & ~(pool)->mask)
+#endif
+
+#define PL_ARENA_ALLOCATE(p, pool, nb) \
+    PR_BEGIN_MACRO \
+        PLArena *_a = (pool)->current; \
+        PRUint32 _nb = PL_ARENA_ALIGN(pool, nb); \
+        PRUword _p = _a->avail; \
+        PRUword _q = _p + _nb; \
+        if (_q > _a->limit) { \
+            _p = (PRUword)PL_ArenaAllocate(pool, _nb); \
+        } else { \
+            _a->avail = _q; \
+        } \
+        p = (void *)_p; \
+        PL_MAKE_MEM_UNDEFINED(p, nb); \
+        PL_ArenaCountAllocation(pool, nb); \
+    PR_END_MACRO
+
+#define PL_ARENA_GROW(p, pool, size, incr) \
+    PR_BEGIN_MACRO \
+        PLArena *_a = (pool)->current; \
+        PRUint32 _incr = PL_ARENA_ALIGN(pool, incr); \
+        PRUword _p = _a->avail; \
+        PRUword _q = _p + _incr; \
+        if (_p == (PRUword)(p) + PL_ARENA_ALIGN(pool, size) && \
+            _q <= _a->limit) { \
+            PL_MAKE_MEM_UNDEFINED((unsigned char *)(p) + size, incr); \
+            _a->avail = _q; \
+            PL_ArenaCountInplaceGrowth(pool, size, incr); \
+        } else { \
+            p = PL_ArenaGrow(pool, p, size, incr); \
+        } \
+        PL_ArenaCountGrowth(pool, size, incr); \
+    PR_END_MACRO
+
+#define PL_ARENA_MARK(pool) ((void *) (pool)->current->avail)
+#define PR_UPTRDIFF(p,q) ((PRUword)(p) - (PRUword)(q))
+
+#define PL_CLEAR_UNUSED_PATTERN(a, pattern) \
+    PR_BEGIN_MACRO \
+        PR_ASSERT((a)->avail <= (a)->limit); \
+        PL_MAKE_MEM_UNDEFINED((void*)(a)->avail, (a)->limit - (a)->avail); \
+        memset((void*)(a)->avail, (pattern), (a)->limit - (a)->avail); \
+    PR_END_MACRO
+#ifdef DEBUG
+#define PL_FREE_PATTERN 0xDA
+#define PL_CLEAR_UNUSED(a) PL_CLEAR_UNUSED_PATTERN((a), PL_FREE_PATTERN)
+#define PL_CLEAR_ARENA(a) \
+    PR_BEGIN_MACRO \
+        PL_MAKE_MEM_UNDEFINED((void*)(a), (a)->limit - (PRUword)(a)); \
+        memset((void*)(a), PL_FREE_PATTERN, (a)->limit - (PRUword)(a)); \
+    PR_END_MACRO
+#else
+#define PL_CLEAR_UNUSED(a)
+#define PL_CLEAR_ARENA(a)
+#endif
+
+#define PL_ARENA_RELEASE(pool, mark) \
+    PR_BEGIN_MACRO \
+        char *_m = (char *)(mark); \
+        PLArena *_a = (pool)->current; \
+        if (PR_UPTRDIFF(_m, _a->base) <= PR_UPTRDIFF(_a->avail, _a->base)) { \
+            _a->avail = (PRUword)PL_ARENA_ALIGN(pool, _m); \
+            PL_CLEAR_UNUSED(_a); \
+            PL_MAKE_MEM_NOACCESS((void*)_a->avail, _a->limit - _a->avail); \
+            PL_ArenaCountRetract(pool, _m); \
+        } else { \
+            PL_ArenaRelease(pool, _m); \
+        } \
+        PL_ArenaCountRelease(pool, _m); \
+    PR_END_MACRO
+
+#ifdef PL_ARENAMETER
+#define PL_COUNT_ARENA(pool,op) ((pool)->stats.narenas op)
+#else
+#define PL_COUNT_ARENA(pool,op)
+#endif
+
+#define PL_ARENA_DESTROY(pool, a, pnext) \
+    PR_BEGIN_MACRO \
+        PL_COUNT_ARENA(pool,--); \
+        if ((pool)->current == (a)) (pool)->current = &(pool)->first; \
+        *(pnext) = (a)->next; \
+        PL_CLEAR_ARENA(a); \
+        free(a); \
+        (a) = 0; \
+    PR_END_MACRO
+
+#ifdef PL_ARENAMETER
+
+#include <stdio.h>
+
+PR_EXTERN(void) PL_ArenaCountAllocation(PLArenaPool *pool, PRUint32 nb);
+
+PR_EXTERN(void) PL_ArenaCountInplaceGrowth(
+    PLArenaPool *pool, PRUint32 size, PRUint32 incr);
+
+PR_EXTERN(void) PL_ArenaCountGrowth(
+    PLArenaPool *pool, PRUint32 size, PRUint32 incr);
+
+PR_EXTERN(void) PL_ArenaCountRelease(PLArenaPool *pool, char *mark);
+
+PR_EXTERN(void) PL_ArenaCountRetract(PLArenaPool *pool, char *mark);
+
+PR_EXTERN(void) PL_DumpArenaStats(FILE *fp);
+
+#else  /* !PL_ARENAMETER */
+
+#define PL_ArenaCountAllocation(ap, nb)                 /* nothing */
+#define PL_ArenaCountInplaceGrowth(ap, size, incr)      /* nothing */
+#define PL_ArenaCountGrowth(ap, size, incr)             /* nothing */
+#define PL_ArenaCountRelease(ap, mark)                  /* nothing */
+#define PL_ArenaCountRetract(ap, mark)                  /* nothing */
+
+#endif /* !PL_ARENAMETER */
+
+PR_END_EXTERN_C
+
+#endif /* plarena_h___ */