Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1112 insertions, 0 deletions

diff --git a/sal/rtl/alloc_arena.cxx b/sal/rtl/alloc_arena.cxx
new file mode 100644
index 000000000..f126efdab
--- /dev/null
+++ b/sal/rtl/alloc_arena.cxx
@@ -0,0 +1,1112 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * 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/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <sal/config.h>
+
+#include "alloc_arena.hxx"
+
+#include "alloc_impl.hxx"
+#include <rtllifecycle.h>
+#include <sal/macros.h>
+
+#include <cassert>
+#include <string.h>
+#include <stdio.h>
+
+namespace {
+
+/**
+    @internal
+*/
+struct rtl_arena_list_st
+{
+    rtl_memory_lock_type m_lock;
+    rtl_arena_type       m_arena_head;
+};
+
+}
+
+static rtl_arena_list_st g_arena_list;
+
+/**
+    provided for arena_type allocations, and hash_table resizing.
+
+    @internal
+*/
+static rtl_arena_type * gp_arena_arena = nullptr;
+
+/**
+    Low level virtual memory (pseudo) arena
+    (platform dependent implementation)
+
+    @internal
+ */
+static rtl_arena_type * gp_machdep_arena = nullptr;
+
+rtl_arena_type * gp_default_arena = nullptr;
+
+namespace
+{
+
+void * rtl_machdep_alloc(
+    rtl_arena_type * pArena,
+    sal_Size *       pSize
+);
+
+void rtl_machdep_free(
+    rtl_arena_type * pArena,
+    void *           pAddr,
+    sal_Size         nSize
+);
+
+sal_Size rtl_machdep_pagesize();
+
+void rtl_arena_segment_constructor(void * obj)
+{
+    rtl_arena_segment_type * segment = static_cast<rtl_arena_segment_type*>(obj);
+
+    QUEUE_START_NAMED(segment, s);
+    QUEUE_START_NAMED(segment, f);
+}
+
+void rtl_arena_segment_destructor(void * obj)
+{
+    rtl_arena_segment_type * segment = static_cast< rtl_arena_segment_type * >(
+        obj);
+    assert(QUEUE_STARTED_NAMED(segment, s));
+    assert(QUEUE_STARTED_NAMED(segment, f));
+    (void) segment; // avoid warnings
+}
+
+/**
+    @precond  arena->m_lock acquired.
+ */
+bool rtl_arena_segment_populate(rtl_arena_type * arena)
+{
+    rtl_arena_segment_type *span;
+    sal_Size                size = rtl_machdep_pagesize();
+
+    span = static_cast< rtl_arena_segment_type * >(
+        rtl_machdep_alloc(gp_machdep_arena, &size));
+    if (span)
+    {
+        rtl_arena_segment_type *first, *last, *head;
+        sal_Size                count = size / sizeof(rtl_arena_segment_type);
+
+        /* insert onto reserve span list */
+        QUEUE_INSERT_TAIL_NAMED(&(arena->m_segment_reserve_span_head), span, s);
+        QUEUE_START_NAMED(span, f);
+        span->m_addr = reinterpret_cast<sal_uIntPtr>(span);
+        span->m_size = size;
+        span->m_type = RTL_ARENA_SEGMENT_TYPE_SPAN;
+
+        /* insert onto reserve list */
+        head  = &(arena->m_segment_reserve_head);
+        for (first = span + 1, last = span + count; first < last; ++first)
+        {
+            QUEUE_INSERT_TAIL_NAMED(head, first, s);
+            QUEUE_START_NAMED(first, f);
+            first->m_addr = 0;
+            first->m_size = 0;
+            first->m_type = 0;
+        }
+    }
+    return (span != nullptr);
+}
+
+/**
+    @precond  arena->m_lock acquired.
+    @precond  (*ppSegment == 0)
+*/
+void rtl_arena_segment_get(
+    rtl_arena_type * arena,
+    rtl_arena_segment_type ** ppSegment
+)
+{
+    rtl_arena_segment_type * head;
+
+    assert(!*ppSegment);
+
+    head = &(arena->m_segment_reserve_head);
+    if (head->m_snext != head || rtl_arena_segment_populate (arena))
+    {
+        (*ppSegment) = head->m_snext;
+        QUEUE_REMOVE_NAMED(*ppSegment, s);
+    }
+}
+
+/**
+    @precond  arena->m_lock acquired.
+    @postcond (*ppSegment == 0)
+ */
+void rtl_arena_segment_put(
+    rtl_arena_type * arena,
+    rtl_arena_segment_type ** ppSegment
+)
+{
+    rtl_arena_segment_type * head;
+
+    assert(QUEUE_STARTED_NAMED(*ppSegment, s));
+    assert(QUEUE_STARTED_NAMED(*ppSegment, f));
+
+    (*ppSegment)->m_addr = 0;
+    (*ppSegment)->m_size = 0;
+
+    assert((*ppSegment)->m_type != RTL_ARENA_SEGMENT_TYPE_HEAD);
+    (*ppSegment)->m_type = 0;
+
+    /* keep as reserve */
+    head = &(arena->m_segment_reserve_head);
+    QUEUE_INSERT_HEAD_NAMED(head, (*ppSegment), s);
+
+    /* clear */
+    (*ppSegment) = nullptr;
+}
+
+/**
+    @precond arena->m_lock acquired.
+*/
+void rtl_arena_freelist_insert (
+    rtl_arena_type * arena,
+    rtl_arena_segment_type * segment
+)
+{
+    rtl_arena_segment_type * head;
+    const auto bit = highbit(segment->m_size);
+    assert(bit > 0);
+    head = &(arena->m_freelist_head[bit - 1]);
+    QUEUE_INSERT_TAIL_NAMED(head, segment, f);
+
+    arena->m_freelist_bitmap |= head->m_size;
+}
+
+/**
+    @precond arena->m_lock acquired.
+*/
+void rtl_arena_freelist_remove(
+    rtl_arena_type * arena,
+    rtl_arena_segment_type * segment
+)
+{
+    if (segment->m_fnext->m_type == RTL_ARENA_SEGMENT_TYPE_HEAD &&
+        segment->m_fprev->m_type == RTL_ARENA_SEGMENT_TYPE_HEAD)
+    {
+        rtl_arena_segment_type * head;
+
+        head = segment->m_fprev;
+        assert(arena->m_freelist_bitmap & head->m_size);
+        arena->m_freelist_bitmap ^= head->m_size;
+    }
+    QUEUE_REMOVE_NAMED(segment, f);
+}
+
+#define RTL_ARENA_HASH_INDEX_IMPL(a, s, q, m) \
+     ((((a) + ((a) >> (s)) + ((a) >> ((s) << 1))) >> (q)) & (m))
+
+#define RTL_ARENA_HASH_INDEX(arena, addr) \
+    RTL_ARENA_HASH_INDEX_IMPL((addr), (arena)->m_hash_shift, (arena)->m_quantum_shift, ((arena)->m_hash_size - 1))
+
+/**
+   @precond arena->m_lock released.
+*/
+void rtl_arena_hash_rescale(
+    rtl_arena_type * arena,
+    sal_Size new_size
+)
+{
+    assert(new_size != 0);
+
+    rtl_arena_segment_type ** new_table;
+    sal_Size                  new_bytes;
+
+    new_bytes = new_size * sizeof(rtl_arena_segment_type*);
+    new_table = static_cast<rtl_arena_segment_type **>(rtl_arena_alloc (gp_arena_arena, &new_bytes));
+
+    if (new_table)
+    {
+        rtl_arena_segment_type ** old_table;
+        sal_Size                  old_size, i;
+
+        memset (new_table, 0, new_bytes);
+
+        RTL_MEMORY_LOCK_ACQUIRE(&(arena->m_lock));
+
+        old_table = arena->m_hash_table;
+        old_size  = arena->m_hash_size;
+
+        arena->m_hash_table = new_table;
+        arena->m_hash_size  = new_size;
+        arena->m_hash_shift = highbit(arena->m_hash_size) - 1;
+
+        for (i = 0; i < old_size; i++)
+        {
+            rtl_arena_segment_type * curr = old_table[i];
+            while (curr)
+            {
+                rtl_arena_segment_type  * next = curr->m_fnext;
+                rtl_arena_segment_type ** head;
+
+                // coverity[negative_shift] - bogus
+                head = &(arena->m_hash_table[RTL_ARENA_HASH_INDEX(arena, curr->m_addr)]);
+                curr->m_fnext = (*head);
+                (*head) = curr;
+
+                curr = next;
+            }
+            old_table[i] = nullptr;
+        }
+
+        RTL_MEMORY_LOCK_RELEASE(&(arena->m_lock));
+
+        if (old_table != arena->m_hash_table_0)
+        {
+            sal_Size old_bytes = old_size * sizeof(rtl_arena_segment_type*);
+            rtl_arena_free (gp_arena_arena, old_table, old_bytes);
+        }
+    }
+}
+
+/**
+    Insert arena hash, and update stats.
+*/
+void rtl_arena_hash_insert(
+    rtl_arena_type * arena,
+    rtl_arena_segment_type * segment
+)
+{
+    rtl_arena_segment_type ** ppSegment;
+
+    ppSegment = &(arena->m_hash_table[RTL_ARENA_HASH_INDEX(arena, segment->m_addr)]);
+
+    segment->m_fnext = (*ppSegment);
+    (*ppSegment) = segment;
+
+    arena->m_stats.m_alloc     += 1;
+    arena->m_stats.m_mem_alloc += segment->m_size;
+}
+
+/**
+    Remove arena hash, and update stats.
+*/
+rtl_arena_segment_type * rtl_arena_hash_remove(
+    rtl_arena_type * arena,
+    sal_uIntPtr addr,
+    sal_Size size
+)
+{
+    rtl_arena_segment_type *segment, **segpp;
+    sal_Size lookups = 0;
+
+    segpp = &(arena->m_hash_table[RTL_ARENA_HASH_INDEX(arena, addr)]);
+    while ((segment = *segpp))
+    {
+        if (segment->m_addr == addr)
+        {
+            *segpp = segment->m_fnext;
+            segment->m_fnext = segment->m_fprev = segment;
+            break;
+        }
+
+        /* update lookup miss stats */
+        lookups += 1;
+        segpp = &(segment->m_fnext);
+    }
+
+    assert(segment); // bad free
+    if (segment)
+    {
+        assert(segment->m_size == size);
+        (void) size; // avoid warnings
+
+        arena->m_stats.m_free      += 1;
+        arena->m_stats.m_mem_alloc -= segment->m_size;
+
+        if (lookups > 1)
+        {
+            sal_Size nseg = static_cast<sal_Size>(arena->m_stats.m_alloc - arena->m_stats.m_free);
+            if (nseg > 4 * arena->m_hash_size)
+            {
+                if (!(arena->m_flags & RTL_ARENA_FLAG_RESCALE))
+                {
+                    sal_Size ave = nseg >> arena->m_hash_shift;
+                    assert(ave != 0);
+                    sal_Size new_size = arena->m_hash_size << (highbit(ave) - 1);
+
+                    arena->m_flags |= RTL_ARENA_FLAG_RESCALE;
+                    RTL_MEMORY_LOCK_RELEASE(&(arena->m_lock));
+                    rtl_arena_hash_rescale (arena, new_size);
+                    RTL_MEMORY_LOCK_ACQUIRE(&(arena->m_lock));
+                    arena->m_flags &= ~RTL_ARENA_FLAG_RESCALE;
+                }
+            }
+        }
+    }
+
+    return segment;
+}
+
+/**
+    allocate (and remove) segment from freelist
+
+    @precond arena->m_lock acquired
+    @precond (*ppSegment == 0)
+*/
+bool rtl_arena_segment_alloc(
+    rtl_arena_type * arena,
+    sal_Size size,
+    rtl_arena_segment_type ** ppSegment
+)
+{
+    int index = 0;
+
+    assert(!*ppSegment);
+    if (!RTL_MEMORY_ISP2(size))
+    {
+        unsigned int msb = highbit(size);
+        if (RTL_ARENA_FREELIST_SIZE == msb)
+        {
+            /* highest possible freelist: fall back to first fit */
+            rtl_arena_segment_type *head, *segment;
+
+            head = &(arena->m_freelist_head[msb - 1]);
+            for (segment = head->m_fnext; segment != head; segment = segment->m_fnext)
+            {
+                if (segment->m_size >= size)
+                {
+                    /* allocate first fit segment */
+                    (*ppSegment) = segment;
+                    break;
+                }
+            }
+            goto dequeue_and_leave;
+        }
+
+        /* roundup to next power of 2 */
+        size = ((sal_Size(1)) << msb);
+    }
+
+    index = lowbit(RTL_MEMORY_P2ALIGN(arena->m_freelist_bitmap, size));
+    if (index > 0)
+    {
+        /* instant fit: allocate first free segment */
+        rtl_arena_segment_type *head;
+
+        head = &(arena->m_freelist_head[index - 1]);
+        (*ppSegment) = head->m_fnext;
+        assert((*ppSegment) != head);
+    }
+
+dequeue_and_leave:
+    if (*ppSegment)
+    {
+        /* remove from freelist */
+        rtl_arena_freelist_remove (arena, (*ppSegment));
+    }
+    return (*ppSegment != nullptr);
+}
+
+/**
+    import new (span) segment from source arena
+
+    @precond arena->m_lock acquired
+    @precond (*ppSegment == 0)
+*/
+bool rtl_arena_segment_create(
+    rtl_arena_type * arena,
+    sal_Size size,
+    rtl_arena_segment_type ** ppSegment
+)
+{
+    assert(!*ppSegment);
+    if (arena->m_source_alloc)
+    {
+        rtl_arena_segment_get (arena, ppSegment);
+        if (*ppSegment)
+        {
+            rtl_arena_segment_type * span = nullptr;
+            rtl_arena_segment_get (arena, &span);
+            if (span)
+            {
+                /* import new span from source arena */
+                RTL_MEMORY_LOCK_RELEASE(&(arena->m_lock));
+
+                span->m_size = size;
+                span->m_addr = reinterpret_cast<sal_uIntPtr>(
+                    (arena->m_source_alloc)(
+                        arena->m_source_arena, &(span->m_size)));
+
+                RTL_MEMORY_LOCK_ACQUIRE(&(arena->m_lock));
+                if (span->m_addr != 0)
+                {
+                    /* insert onto segment list, update stats */
+                    span->m_type = RTL_ARENA_SEGMENT_TYPE_SPAN;
+                    QUEUE_INSERT_HEAD_NAMED(&(arena->m_segment_head), span, s);
+                    arena->m_stats.m_mem_total += span->m_size;
+
+                    (*ppSegment)->m_addr = span->m_addr;
+                    (*ppSegment)->m_size = span->m_size;
+                    (*ppSegment)->m_type = RTL_ARENA_SEGMENT_TYPE_FREE;
+                    QUEUE_INSERT_HEAD_NAMED(span, (*ppSegment), s);
+
+                    /* report success */
+                    return true;
+                }
+                rtl_arena_segment_put (arena, &span);
+            }
+            rtl_arena_segment_put (arena, ppSegment);
+        }
+    }
+    return false; // failure
+}
+
+/**
+    mark as free and join with adjacent free segment(s)
+
+    @precond arena->m_lock acquired
+    @precond segment marked 'used'
+*/
+void rtl_arena_segment_coalesce(
+    rtl_arena_type * arena,
+    rtl_arena_segment_type * segment
+)
+{
+    rtl_arena_segment_type *next, *prev;
+
+    /* mark segment free */
+    assert(segment->m_type == RTL_ARENA_SEGMENT_TYPE_USED);
+    segment->m_type = RTL_ARENA_SEGMENT_TYPE_FREE;
+
+    /* try to merge w/ next segment */
+    next = segment->m_snext;
+    if (next->m_type == RTL_ARENA_SEGMENT_TYPE_FREE)
+    {
+        assert(segment->m_addr + segment->m_size == next->m_addr);
+        segment->m_size += next->m_size;
+
+        /* remove from freelist */
+        rtl_arena_freelist_remove (arena, next);
+
+        /* remove from segment list */
+        QUEUE_REMOVE_NAMED(next, s);
+
+        /* release segment descriptor */
+        rtl_arena_segment_put (arena, &next);
+    }
+
+    /* try to merge w/ prev segment */
+    prev = segment->m_sprev;
+    if (prev->m_type == RTL_ARENA_SEGMENT_TYPE_FREE)
+    {
+        assert(prev->m_addr + prev->m_size == segment->m_addr);
+        segment->m_addr  = prev->m_addr;
+        segment->m_size += prev->m_size;
+
+        /* remove from freelist */
+        rtl_arena_freelist_remove (arena, prev);
+
+        /* remove from segment list */
+        QUEUE_REMOVE_NAMED(prev, s);
+
+        /* release segment descriptor */
+        rtl_arena_segment_put (arena, &prev);
+    }
+}
+
+void rtl_arena_constructor(void * obj)
+{
+    rtl_arena_type * arena = static_cast<rtl_arena_type*>(obj);
+    rtl_arena_segment_type * head;
+    size_t i;
+
+    memset (arena, 0, sizeof(rtl_arena_type));
+
+    QUEUE_START_NAMED(arena, arena_);
+
+    RTL_MEMORY_LOCK_INIT(&(arena->m_lock));
+
+    head = &(arena->m_segment_reserve_span_head);
+    rtl_arena_segment_constructor (head);
+    head->m_type = RTL_ARENA_SEGMENT_TYPE_HEAD;
+
+    head = &(arena->m_segment_reserve_head);
+    rtl_arena_segment_constructor (head);
+    head->m_type = RTL_ARENA_SEGMENT_TYPE_HEAD;
+
+    head = &(arena->m_segment_head);
+    rtl_arena_segment_constructor (head);
+    head->m_type = RTL_ARENA_SEGMENT_TYPE_HEAD;
+
+    for (i = 0; i < RTL_ARENA_FREELIST_SIZE; i++)
+    {
+        head = &(arena->m_freelist_head[i]);
+        rtl_arena_segment_constructor (head);
+
+        head->m_size = ((sal_Size(1)) << i);
+        head->m_type = RTL_ARENA_SEGMENT_TYPE_HEAD;
+    }
+
+    arena->m_hash_table = arena->m_hash_table_0;
+    arena->m_hash_size  = RTL_ARENA_HASH_SIZE;
+    arena->m_hash_shift = highbit(arena->m_hash_size) - 1;
+}
+
+void rtl_arena_destructor(void * obj)
+{
+    rtl_arena_type * arena = static_cast<rtl_arena_type*>(obj);
+    rtl_arena_segment_type * head;
+    size_t i;
+
+    assert(QUEUE_STARTED_NAMED(arena, arena_));
+
+    RTL_MEMORY_LOCK_DESTROY(&(arena->m_lock));
+
+    head = &(arena->m_segment_reserve_span_head);
+    assert(head->m_type == RTL_ARENA_SEGMENT_TYPE_HEAD);
+    rtl_arena_segment_destructor (head);
+
+    head = &(arena->m_segment_reserve_head);
+    assert(head->m_type == RTL_ARENA_SEGMENT_TYPE_HEAD);
+    rtl_arena_segment_destructor (head);
+
+    head = &(arena->m_segment_head);
+    assert(head->m_type == RTL_ARENA_SEGMENT_TYPE_HEAD);
+    rtl_arena_segment_destructor (head);
+
+    for (i = 0; i < RTL_ARENA_FREELIST_SIZE; i++)
+    {
+        head = &(arena->m_freelist_head[i]);
+
+        assert(head->m_size == ((sal_Size(1)) << i));
+        assert(head->m_type == RTL_ARENA_SEGMENT_TYPE_HEAD);
+
+        rtl_arena_segment_destructor (head);
+    }
+
+    assert(arena->m_hash_table == arena->m_hash_table_0);
+    assert(arena->m_hash_size  == RTL_ARENA_HASH_SIZE);
+    assert(arena->m_hash_shift == highbit(arena->m_hash_size) - 1);
+}
+
+rtl_arena_type * rtl_arena_activate(
+    rtl_arena_type * arena,
+    const char *     name,
+    sal_Size         quantum,
+    rtl_arena_type * source_arena,
+    void * (SAL_CALL * source_alloc)(rtl_arena_type *, sal_Size *),
+    void   (SAL_CALL * source_free) (rtl_arena_type *, void *, sal_Size)
+)
+{
+    assert(arena);
+    if (arena)
+    {
+        (void) snprintf (arena->m_name, sizeof(arena->m_name), "%s", name);
+
+        if (!RTL_MEMORY_ISP2(quantum))
+        {
+            /* roundup to next power of 2 */
+            quantum = ((sal_Size(1)) << highbit(quantum));
+        }
+
+        arena->m_quantum = quantum;
+        arena->m_quantum_shift = highbit(arena->m_quantum) - 1;
+
+        arena->m_source_arena = source_arena;
+        arena->m_source_alloc = source_alloc;
+        arena->m_source_free  = source_free;
+
+        /* insert into arena list */
+        RTL_MEMORY_LOCK_ACQUIRE(&(g_arena_list.m_lock));
+        QUEUE_INSERT_TAIL_NAMED(&(g_arena_list.m_arena_head), arena, arena_);
+        RTL_MEMORY_LOCK_RELEASE(&(g_arena_list.m_lock));
+    }
+    return arena;
+}
+
+void rtl_arena_deactivate(rtl_arena_type * arena)
+{
+    rtl_arena_segment_type * head, * segment;
+
+    /* remove from arena list */
+    RTL_MEMORY_LOCK_ACQUIRE(&(g_arena_list.m_lock));
+    QUEUE_REMOVE_NAMED(arena, arena_);
+    RTL_MEMORY_LOCK_RELEASE(&(g_arena_list.m_lock));
+
+    /* check for leaked segments */
+    if (arena->m_stats.m_alloc > arena->m_stats.m_free)
+    {
+        sal_Size i, n;
+
+        /* cleanup still used segment(s) */
+        for (i = 0, n = arena->m_hash_size; i < n; i++)
+        {
+            while ((segment = arena->m_hash_table[i]))
+            {
+                /* pop from hash table */
+                arena->m_hash_table[i] = segment->m_fnext;
+                segment->m_fnext = segment->m_fprev = segment;
+
+                /* coalesce w/ adjacent free segment(s) */
+                rtl_arena_segment_coalesce (arena, segment);
+
+                /* insert onto freelist */
+                rtl_arena_freelist_insert (arena, segment);
+            }
+        }
+    }
+
+    /* cleanup hash table */
+    if (arena->m_hash_table != arena->m_hash_table_0)
+    {
+        rtl_arena_free(
+            gp_arena_arena,
+            arena->m_hash_table,
+            arena->m_hash_size * sizeof(rtl_arena_segment_type*));
+
+        arena->m_hash_table = arena->m_hash_table_0;
+        arena->m_hash_size = RTL_ARENA_HASH_SIZE;
+        arena->m_hash_shift = highbit(arena->m_hash_size) - 1;
+    }
+
+    /* cleanup segment list */
+    head = &(arena->m_segment_head);
+    for (segment = head->m_snext; segment != head; segment = head->m_snext)
+    {
+        if (segment->m_type == RTL_ARENA_SEGMENT_TYPE_FREE)
+        {
+            /* remove from freelist */
+            rtl_arena_freelist_remove (arena, segment);
+        }
+        else
+        {
+            /* can have only free and span segments here */
+            assert(segment->m_type == RTL_ARENA_SEGMENT_TYPE_SPAN);
+        }
+
+        /* remove from segment list */
+        QUEUE_REMOVE_NAMED(segment, s);
+
+        /* release segment descriptor */
+        rtl_arena_segment_put (arena, &segment);
+    }
+
+    /* cleanup segment reserve list */
+    head = &(arena->m_segment_reserve_head);
+    for (segment = head->m_snext; segment != head; segment = head->m_snext)
+    {
+        /* remove from segment list */
+        QUEUE_REMOVE_NAMED(segment, s);
+    }
+
+    /* cleanup segment reserve span(s) */
+    head = &(arena->m_segment_reserve_span_head);
+    for (segment = head->m_snext; segment != head; segment = head->m_snext)
+    {
+        /* can have only span segments here */
+        assert(segment->m_type == RTL_ARENA_SEGMENT_TYPE_SPAN);
+
+        /* remove from segment list */
+        QUEUE_REMOVE_NAMED(segment, s);
+
+        /* return span to g_machdep_arena */
+        rtl_machdep_free (gp_machdep_arena, reinterpret_cast<void*>(segment->m_addr), segment->m_size);
+    }
+}
+
+} // namespace
+
+rtl_arena_type * SAL_CALL rtl_arena_create(
+    const char *       name,
+    sal_Size           quantum,
+    sal_Size,
+    rtl_arena_type *   source_arena,
+    void * (SAL_CALL * source_alloc)(rtl_arena_type *, sal_Size *),
+    void   (SAL_CALL * source_free) (rtl_arena_type *, void *, sal_Size),
+    SAL_UNUSED_PARAMETER int
+) SAL_THROW_EXTERN_C()
+{
+    rtl_arena_type * result = nullptr;
+    sal_Size         size   = sizeof(rtl_arena_type);
+
+try_alloc:
+    result = static_cast<rtl_arena_type*>(rtl_arena_alloc (gp_arena_arena, &size));
+    if (result)
+    {
+        rtl_arena_type * arena = result;
+        rtl_arena_constructor (arena);
+
+        if (!source_arena)
+        {
+            assert(gp_default_arena);
+            source_arena = gp_default_arena;
+        }
+
+        result = rtl_arena_activate (
+            arena,
+            name,
+            quantum,
+            source_arena,
+            source_alloc,
+            source_free
+        );
+
+        if (!result)
+        {
+            rtl_arena_deactivate (arena);
+            rtl_arena_destructor (arena);
+            rtl_arena_free (gp_arena_arena, arena, size);
+        }
+    }
+    else if (!gp_arena_arena)
+    {
+        ensureArenaSingleton();
+        if (gp_arena_arena)
+        {
+            /* try again */
+            goto try_alloc;
+        }
+    }
+    return result;
+}
+
+void SAL_CALL rtl_arena_destroy(rtl_arena_type * arena) SAL_THROW_EXTERN_C()
+{
+    if (arena)
+    {
+        rtl_arena_deactivate (arena);
+        rtl_arena_destructor (arena);
+        rtl_arena_free (gp_arena_arena, arena, sizeof(rtl_arena_type));
+    }
+}
+
+void * SAL_CALL rtl_arena_alloc(
+    rtl_arena_type * arena,
+    sal_Size *       pSize
+) SAL_THROW_EXTERN_C()
+{
+    void * addr = nullptr;
+
+    if (arena && pSize)
+    {
+        sal_Size size;
+
+        size = RTL_MEMORY_ALIGN(*pSize, arena->m_quantum);
+        if (size > 0)
+        {
+            /* allocate from segment list */
+            rtl_arena_segment_type *segment = nullptr;
+
+            RTL_MEMORY_LOCK_ACQUIRE(&(arena->m_lock));
+            if (rtl_arena_segment_alloc (arena, size, &segment) ||
+                rtl_arena_segment_create(arena, size, &segment)    )
+            {
+                /* shrink to fit */
+                sal_Size oversize;
+
+                /* mark segment used */
+                assert(segment->m_type == RTL_ARENA_SEGMENT_TYPE_FREE);
+                segment->m_type = RTL_ARENA_SEGMENT_TYPE_USED;
+
+                /* resize */
+                assert(segment->m_size >= size);
+                oversize = segment->m_size - size;
+                if (oversize >= arena->m_quantum)
+                {
+                    rtl_arena_segment_type * remainder = nullptr;
+                    rtl_arena_segment_get (arena, &remainder);
+                    if (remainder)
+                    {
+                        segment->m_size = size;
+
+                        remainder->m_addr = segment->m_addr + segment->m_size;
+                        remainder->m_size = oversize;
+                        remainder->m_type = RTL_ARENA_SEGMENT_TYPE_FREE;
+                        QUEUE_INSERT_HEAD_NAMED(segment, remainder, s);
+
+                        rtl_arena_freelist_insert (arena, remainder);
+                    }
+                }
+
+                rtl_arena_hash_insert (arena, segment);
+
+                (*pSize) = segment->m_size;
+                addr = reinterpret_cast<void*>(segment->m_addr);
+            }
+            RTL_MEMORY_LOCK_RELEASE(&(arena->m_lock));
+        }
+    }
+    return addr;
+}
+
+void SAL_CALL rtl_arena_free (
+    rtl_arena_type * arena,
+    void *           addr,
+    sal_Size         size
+) SAL_THROW_EXTERN_C()
+{
+    if (arena)
+    {
+        size = RTL_MEMORY_ALIGN(size, arena->m_quantum);
+        if (size > 0)
+        {
+            /* free to segment list */
+            rtl_arena_segment_type * segment;
+
+            RTL_MEMORY_LOCK_ACQUIRE(&(arena->m_lock));
+
+            segment = rtl_arena_hash_remove (arena, reinterpret_cast<sal_uIntPtr>(addr), size);
+            if (segment)
+            {
+                rtl_arena_segment_type *next, *prev;
+
+                /* coalesce w/ adjacent free segment(s) */
+                rtl_arena_segment_coalesce (arena, segment);
+
+                /* determine (new) next and prev segment */
+                next = segment->m_snext;
+                prev = segment->m_sprev;
+
+                /* entire span free when prev is a span, and next is either a span or a list head */
+                if (prev->m_type == RTL_ARENA_SEGMENT_TYPE_SPAN &&
+                    ((next->m_type == RTL_ARENA_SEGMENT_TYPE_SPAN)  ||
+                     (next->m_type == RTL_ARENA_SEGMENT_TYPE_HEAD)))
+                {
+                    assert(
+                        prev->m_addr == segment->m_addr
+                        && prev->m_size == segment->m_size);
+
+                    if (arena->m_source_free)
+                    {
+                        addr = reinterpret_cast<void*>(prev->m_addr);
+                        size = prev->m_size;
+
+                        /* remove from segment list */
+                        QUEUE_REMOVE_NAMED(segment, s);
+
+                        /* release segment descriptor */
+                        rtl_arena_segment_put (arena, &segment);
+
+                        /* remove from segment list */
+                        QUEUE_REMOVE_NAMED(prev, s);
+
+                        /* release (span) segment descriptor */
+                        rtl_arena_segment_put (arena, &prev);
+
+                        /* update stats, return span to source arena */
+                        arena->m_stats.m_mem_total -= size;
+                        RTL_MEMORY_LOCK_RELEASE(&(arena->m_lock));
+
+                        (arena->m_source_free)(arena->m_source_arena, addr, size);
+                        return;
+                    }
+                }
+
+                /* insert onto freelist */
+                rtl_arena_freelist_insert (arena, segment);
+            }
+
+            RTL_MEMORY_LOCK_RELEASE(&(arena->m_lock));
+        }
+    }
+}
+
+void rtl_arena_foreach (rtl_arena_type *arena, ArenaForeachFn foreachFn)
+{
+    /* used segments */
+    for (int i = 0, n = arena->m_hash_size; i < n; i++)
+    {
+        for (rtl_arena_segment_type *segment = arena->m_hash_table[i];
+             segment != nullptr; segment = segment->m_fnext)
+        {
+            foreachFn(reinterpret_cast<void *>(segment->m_addr),
+                      segment->m_size);
+        }
+    }
+}
+
+#if defined(SAL_UNX)
+#include <sys/mman.h>
+#elif defined(_WIN32)
+#define MAP_FAILED nullptr
+#endif /* SAL_UNX || _WIN32 */
+
+namespace
+{
+
+void * rtl_machdep_alloc(
+    rtl_arena_type * pArena,
+    sal_Size *       pSize
+)
+{
+    void *   addr;
+    sal_Size size = *pSize;
+
+    assert(pArena == gp_machdep_arena);
+
+#if defined(__sun) && defined(SPARC)
+    /* see @ mmap(2) man pages */
+    size += (pArena->m_quantum + pArena->m_quantum); /* "red-zone" pages */
+    if (size > (4 << 20))
+        size = RTL_MEMORY_P2ROUNDUP(size, (4 << 20));
+    else if (size > (512 << 10))
+        size = RTL_MEMORY_P2ROUNDUP(size, (512 << 10));
+    else
+        size = RTL_MEMORY_P2ROUNDUP(size, (64 << 10));
+    size -= (pArena->m_quantum + pArena->m_quantum); /* "red-zone" pages */
+#else
+    /* default allocation granularity */
+    if (pArena->m_quantum < (64 << 10))
+    {
+        size = RTL_MEMORY_P2ROUNDUP(size, (64 << 10));
+    }
+    else
+    {
+        size = RTL_MEMORY_P2ROUNDUP(size, pArena->m_quantum);
+    }
+#endif
+
+#if defined(SAL_UNX)
+    addr = mmap (nullptr, static_cast<size_t>(size), PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
+#elif defined(_WIN32)
+    addr = VirtualAlloc (nullptr, static_cast<SIZE_T>(size), MEM_COMMIT, PAGE_READWRITE);
+#endif /* (SAL_UNX || _WIN32) */
+
+    if (addr != MAP_FAILED)
+    {
+        pArena->m_stats.m_alloc += 1;
+        pArena->m_stats.m_mem_total += size;
+        pArena->m_stats.m_mem_alloc += size;
+
+        (*pSize) = size;
+        return addr;
+    }
+    return nullptr;
+}
+
+void rtl_machdep_free(
+    rtl_arena_type * pArena,
+    void *           pAddr,
+    sal_Size         nSize
+)
+{
+    assert(pArena == gp_machdep_arena);
+
+    pArena->m_stats.m_free += 1;
+    pArena->m_stats.m_mem_total -= nSize;
+    pArena->m_stats.m_mem_alloc -= nSize;
+
+#if defined(SAL_UNX)
+    (void) munmap(pAddr, nSize);
+#elif defined(_WIN32)
+    (void) VirtualFree (pAddr, SIZE_T(0), MEM_RELEASE);
+#endif /* (SAL_UNX || _WIN32) */
+}
+
+sal_Size rtl_machdep_pagesize()
+{
+#if defined(SAL_UNX)
+#if defined(FREEBSD) || defined(NETBSD) || defined(DRAGONFLY)
+    return (sal_Size)getpagesize();
+#else  /* POSIX */
+    return static_cast<sal_Size>(sysconf(_SC_PAGESIZE));
+#endif /* xBSD || POSIX */
+#elif defined(_WIN32)
+    SYSTEM_INFO info;
+    GetSystemInfo (&info);
+    return static_cast<sal_Size>(info.dwPageSize);
+#endif /* (SAL_UNX || _WIN32) */
+}
+
+} //namespace
+
+void rtl_arena_init()
+{
+    {
+        /* list of arenas */
+        RTL_MEMORY_LOCK_INIT(&(g_arena_list.m_lock));
+        rtl_arena_constructor (&(g_arena_list.m_arena_head));
+    }
+    {
+        /* machdep (pseudo) arena */
+        static rtl_arena_type g_machdep_arena;
+
+        assert(!gp_machdep_arena);
+        rtl_arena_constructor (&g_machdep_arena);
+
+        gp_machdep_arena = rtl_arena_activate (
+            &g_machdep_arena,
+            "rtl_machdep_arena",
+            rtl_machdep_pagesize(),
+            nullptr, nullptr, nullptr  /* no source */
+        );
+        assert(gp_machdep_arena);
+    }
+    {
+        /* default arena */
+        static rtl_arena_type g_default_arena;
+
+        assert(!gp_default_arena);
+        rtl_arena_constructor (&g_default_arena);
+
+        gp_default_arena = rtl_arena_activate (
+            &g_default_arena,
+            "rtl_default_arena",
+            rtl_machdep_pagesize(),
+            gp_machdep_arena,  /* source */
+            rtl_machdep_alloc,
+            rtl_machdep_free
+        );
+        assert(gp_default_arena);
+    }
+    {
+        /* arena internal arena */
+        static rtl_arena_type g_arena_arena;
+
+        assert(!gp_arena_arena);
+        rtl_arena_constructor (&g_arena_arena);
+
+        gp_arena_arena = rtl_arena_activate(
+            &g_arena_arena,
+            "rtl_arena_internal_arena",
+            64,                /* quantum */
+            gp_default_arena,  /* source */
+            rtl_arena_alloc,
+            rtl_arena_free
+        );
+        assert(gp_arena_arena);
+    }
+}
+
+void rtl_arena_fini()
+{
+    if (gp_arena_arena)
+    {
+        rtl_arena_type * arena, * head;
+
+        RTL_MEMORY_LOCK_ACQUIRE(&(g_arena_list.m_lock));
+        head = &(g_arena_list.m_arena_head);
+
+        for (arena = head->m_arena_next; arena != head; arena = arena->m_arena_next)
+        {
+            // noop
+        }
+        RTL_MEMORY_LOCK_RELEASE(&(g_arena_list.m_lock));
+    }
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */