1 files changed, 880 insertions, 0 deletions

diff --git a/src/lisp/ao_lisp_mem.c b/src/lisp/ao_lisp_mem.c
new file mode 100644
index 00000000..d067ea07
--- /dev/null
+++ b/src/lisp/ao_lisp_mem.c
@@ -0,0 +1,880 @@
+/*
+ * Copyright © 2016 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#define AO_LISP_CONST_BITS
+
+#include "ao_lisp.h"
+#include <stdio.h>
+
+#ifdef AO_LISP_MAKE_CONST
+
+/*
+ * When building the constant table, it is the
+ * pool for allocations.
+ */
+
+#include <stdlib.h>
+uint8_t ao_lisp_const[AO_LISP_POOL_CONST] __attribute__((aligned(4)));
+#define ao_lisp_pool ao_lisp_const
+#undef AO_LISP_POOL
+#define AO_LISP_POOL AO_LISP_POOL_CONST
+
+#else
+
+uint8_t	ao_lisp_pool[AO_LISP_POOL + AO_LISP_POOL_EXTRA] __attribute__((aligned(4)));
+
+#endif
+
+#ifndef DBG_MEM_STATS
+#define DBG_MEM_STATS	DBG_MEM
+#endif
+
+#if DBG_MEM
+int dbg_move_depth;
+int dbg_mem = DBG_MEM_START;
+int dbg_validate = 0;
+
+struct ao_lisp_record {
+	struct ao_lisp_record		*next;
+	const struct ao_lisp_type	*type;
+	void				*addr;
+	int				size;
+};
+
+static struct ao_lisp_record	*record_head, **record_tail;
+
+static void
+ao_lisp_record_free(struct ao_lisp_record *record)
+{
+	while (record) {
+		struct ao_lisp_record *next = record->next;
+		free(record);
+		record = next;
+	}
+}
+
+static void
+ao_lisp_record_reset(void)
+{
+	ao_lisp_record_free(record_head);
+	record_head = NULL;
+	record_tail = &record_head;
+}
+
+static void
+ao_lisp_record(const struct ao_lisp_type	*type,
+	       void				*addr,
+	       int				size)
+{
+	struct ao_lisp_record	*r = malloc(sizeof (struct ao_lisp_record));
+
+	r->next = NULL;
+	r->type = type;
+	r->addr = addr;
+	r->size = size;
+	*record_tail = r;
+	record_tail = &r->next;
+}
+
+static struct ao_lisp_record *
+ao_lisp_record_save(void)
+{
+	struct ao_lisp_record *r = record_head;
+
+	record_head = NULL;
+	record_tail = &record_head;
+	return r;
+}
+
+static void
+ao_lisp_record_compare(char *where,
+		       struct ao_lisp_record *a,
+		       struct ao_lisp_record *b)
+{
+	while (a && b) {
+		if (a->type != b->type || a->size != b->size) {
+			printf("%s record difers %d %s %d -> %d %s %d\n",
+			       where,
+			       MDBG_OFFSET(a->addr),
+			       a->type->name,
+			       a->size,
+			       MDBG_OFFSET(b->addr),
+			       b->type->name,
+			       b->size);
+			ao_lisp_abort();
+		}
+		a = a->next;
+		b = b->next;
+	}
+	if (a) {
+		printf("%s record differs %d %s %d -> NULL\n",
+		       where,
+		       MDBG_OFFSET(a->addr),
+		       a->type->name,
+		       a->size);
+		ao_lisp_abort();
+	}
+	if (b) {
+		printf("%s record differs NULL -> %d %s %d\n",
+		       where,
+		       MDBG_OFFSET(b->addr),
+		       b->type->name,
+		       b->size);
+		ao_lisp_abort();
+	}
+}
+
+#else
+#define ao_lisp_record_reset()
+#endif
+
+uint8_t	ao_lisp_exception;
+
+struct ao_lisp_root {
+	const struct ao_lisp_type	*type;
+	void				**addr;
+};
+
+static struct ao_lisp_cons 	*save_cons[2];
+static char			*save_string[2];
+static ao_poly			save_poly[3];
+
+static const struct ao_lisp_root	ao_lisp_root[] = {
+	{
+		.type = &ao_lisp_cons_type,
+		.addr = (void **) &save_cons[0],
+	},
+	{
+		.type = &ao_lisp_cons_type,
+		.addr = (void **) &save_cons[1],
+	},
+	{
+		.type = &ao_lisp_string_type,
+		.addr = (void **) &save_string[0],
+	},
+	{
+		.type = &ao_lisp_string_type,
+		.addr = (void **) &save_string[1],
+	},
+	{
+		.type = NULL,
+		.addr = (void **) (void *) &save_poly[0]
+	},
+	{
+		.type = NULL,
+		.addr = (void **) (void *) &save_poly[1]
+	},
+	{
+		.type = NULL,
+		.addr = (void **) (void *) &save_poly[2]
+	},
+	{
+		.type = &ao_lisp_atom_type,
+		.addr = (void **) &ao_lisp_atoms
+	},
+	{
+		.type = &ao_lisp_frame_type,
+		.addr = (void **) &ao_lisp_frame_global,
+	},
+	{
+		.type = &ao_lisp_frame_type,
+		.addr = (void **) &ao_lisp_frame_current,
+	},
+	{
+		.type = &ao_lisp_stack_type,
+		.addr = (void **) &ao_lisp_stack,
+	},
+	{
+		.type = NULL,
+		.addr = (void **) (void *) &ao_lisp_v,
+	},
+	{
+		.type = &ao_lisp_cons_type,
+		.addr = (void **) &ao_lisp_read_cons,
+	},
+	{
+		.type = &ao_lisp_cons_type,
+		.addr = (void **) &ao_lisp_read_cons_tail,
+	},
+	{
+		.type = &ao_lisp_cons_type,
+		.addr = (void **) &ao_lisp_read_stack,
+	},
+};
+
+#define AO_LISP_ROOT	(sizeof (ao_lisp_root) / sizeof (ao_lisp_root[0]))
+
+static const void ** const ao_lisp_cache[] = {
+	(const void **) &ao_lisp_cons_free_list,
+	(const void **) &ao_lisp_stack_free_list,
+	(const void **) &ao_lisp_frame_free_list[0],
+	(const void **) &ao_lisp_frame_free_list[1],
+	(const void **) &ao_lisp_frame_free_list[2],
+	(const void **) &ao_lisp_frame_free_list[3],
+	(const void **) &ao_lisp_frame_free_list[4],
+	(const void **) &ao_lisp_frame_free_list[5],
+};
+
+#if AO_LISP_FRAME_FREE != 6
+#error Unexpected AO_LISP_FRAME_FREE value
+#endif
+
+#define AO_LISP_CACHE	(sizeof (ao_lisp_cache) / sizeof (ao_lisp_cache[0]))
+
+#define AO_LISP_BUSY_SIZE	((AO_LISP_POOL + 31) / 32)
+
+static uint8_t	ao_lisp_busy[AO_LISP_BUSY_SIZE];
+static uint8_t	ao_lisp_cons_note[AO_LISP_BUSY_SIZE];
+static uint8_t	ao_lisp_cons_last[AO_LISP_BUSY_SIZE];
+static uint8_t	ao_lisp_cons_noted;
+
+uint16_t	ao_lisp_top;
+
+struct ao_lisp_chunk {
+	uint16_t		old_offset;
+	union {
+		uint16_t	size;
+		uint16_t	new_offset;
+	};
+};
+
+#define AO_LISP_NCHUNK	64
+
+static struct ao_lisp_chunk ao_lisp_chunk[AO_LISP_NCHUNK];
+
+/* Offset of an address within the pool. */
+static inline uint16_t pool_offset(void *addr) {
+#if DBG_MEM
+	if (!AO_LISP_IS_POOL(addr))
+		ao_lisp_abort();
+#endif
+	return ((uint8_t *) addr) - ao_lisp_pool;
+}
+
+static inline void mark(uint8_t *tag, int offset) {
+	int	byte = offset >> 5;
+	int	bit = (offset >> 2) & 7;
+	tag[byte] |= (1 << bit);
+}
+
+static inline void clear(uint8_t *tag, int offset) {
+	int	byte = offset >> 5;
+	int	bit = (offset >> 2) & 7;
+	tag[byte] &= ~(1 << bit);
+}
+
+static inline int busy(uint8_t *tag, int offset) {
+	int	byte = offset >> 5;
+	int	bit = (offset >> 2) & 7;
+	return (tag[byte] >> bit) & 1;
+}
+
+static inline int min(int a, int b) { return a < b ? a : b; }
+static inline int max(int a, int b) { return a > b ? a : b; }
+
+static inline int limit(int offset) {
+	return min(AO_LISP_POOL, max(offset, 0));
+}
+
+static void
+note_cons(uint16_t offset)
+{
+	MDBG_MOVE("note cons %d\n", offset);
+	ao_lisp_cons_noted = 1;
+	mark(ao_lisp_cons_note, offset);
+}
+
+static uint16_t	chunk_low, chunk_high;
+static uint16_t	chunk_first, chunk_last;
+
+static int
+find_chunk(uint16_t offset)
+{
+	int l, r;
+	/* Binary search for the location */
+	l = chunk_first;
+	r = chunk_last - 1;
+	while (l <= r) {
+		int m = (l + r) >> 1;
+		if (ao_lisp_chunk[m].old_offset < offset)
+			l = m + 1;
+		else
+			r = m - 1;
+	}
+	return l;
+}
+
+static void
+note_chunk(uint16_t offset, uint16_t size)
+{
+	int l;
+
+	if (offset < chunk_low || chunk_high <= offset)
+		return;
+
+	l = find_chunk(offset);
+
+	/*
+	 * The correct location is always in 'l', with r = l-1 being
+	 * the entry before the right one
+	 */
+
+#if DBG_MEM
+	/* Off the right side */
+	if (l >= AO_LISP_NCHUNK)
+		ao_lisp_abort();
+
+	/* Off the left side */
+	if (l == 0 && chunk_last && offset > ao_lisp_chunk[0].old_offset)
+		ao_lisp_abort();
+#endif
+
+	/* Shuffle existing entries right */
+	int end = min(AO_LISP_NCHUNK, chunk_last + 1);
+
+	memmove(&ao_lisp_chunk[l+1],
+		&ao_lisp_chunk[l],
+		(end - (l+1)) * sizeof (struct ao_lisp_chunk));
+
+	/* Add new entry */
+	ao_lisp_chunk[l].old_offset = offset;
+	ao_lisp_chunk[l].size = size;
+
+	/* Increment the number of elements up to the size of the array */
+	if (chunk_last < AO_LISP_NCHUNK)
+		chunk_last++;
+
+	/* Set the top address if the array is full */
+	if (chunk_last == AO_LISP_NCHUNK)
+		chunk_high = ao_lisp_chunk[AO_LISP_NCHUNK-1].old_offset +
+			ao_lisp_chunk[AO_LISP_NCHUNK-1].size;
+}
+
+static void
+reset_chunks(void)
+{
+	chunk_high = ao_lisp_top;
+	chunk_last = 0;
+	chunk_first = 0;
+}
+
+/*
+ * Walk all referenced objects calling functions on each one
+ */
+
+static void
+walk(int (*visit_addr)(const struct ao_lisp_type *type, void **addr),
+     int (*visit_poly)(ao_poly *p, uint8_t do_note_cons))
+{
+	int i;
+
+	ao_lisp_record_reset();
+	memset(ao_lisp_busy, '\0', sizeof (ao_lisp_busy));
+	memset(ao_lisp_cons_note, '\0', sizeof (ao_lisp_cons_note));
+	ao_lisp_cons_noted = 0;
+	for (i = 0; i < (int) AO_LISP_ROOT; i++) {
+		if (ao_lisp_root[i].type) {
+			void **a = ao_lisp_root[i].addr, *v;
+			if (a && (v = *a)) {
+				MDBG_MOVE("root ptr %d\n", MDBG_OFFSET(v));
+				visit_addr(ao_lisp_root[i].type, a);
+			}
+		} else {
+			ao_poly *a = (ao_poly *) ao_lisp_root[i].addr, p;
+			if (a && (p = *a)) {
+				MDBG_MOVE("root poly %d\n", MDBG_OFFSET(ao_lisp_ref(p)));
+				visit_poly(a, 0);
+			}
+		}
+	}
+	while (ao_lisp_cons_noted) {
+		memcpy(ao_lisp_cons_last, ao_lisp_cons_note, sizeof (ao_lisp_cons_note));
+		memset(ao_lisp_cons_note, '\0', sizeof (ao_lisp_cons_note));
+		ao_lisp_cons_noted = 0;
+		for (i = 0; i < AO_LISP_POOL; i += 4) {
+			if (busy(ao_lisp_cons_last, i)) {
+				void *v = ao_lisp_pool + i;
+				MDBG_MOVE("root cons %d\n", MDBG_OFFSET(v));
+				visit_addr(&ao_lisp_cons_type, &v);
+			}
+		}
+	}
+}
+
+#if MDBG_DUMP
+static void
+dump_busy(void)
+{
+	int	i;
+	MDBG_MOVE("busy:");
+	for (i = 0; i < ao_lisp_top; i += 4) {
+		if ((i & 0xff) == 0) {
+			MDBG_MORE("\n");
+			MDBG_MOVE("%s", "");
+		}
+		else if ((i & 0x1f) == 0)
+			MDBG_MORE(" ");
+		if (busy(ao_lisp_busy, i))
+			MDBG_MORE("*");
+		else
+			MDBG_MORE("-");
+	}
+	MDBG_MORE ("\n");
+}
+#define DUMP_BUSY()	dump_busy()
+#else
+#define DUMP_BUSY()
+#endif
+
+static const struct ao_lisp_type const *ao_lisp_types[AO_LISP_NUM_TYPE] = {
+	[AO_LISP_CONS] = &ao_lisp_cons_type,
+	[AO_LISP_INT] = NULL,
+	[AO_LISP_STRING] = &ao_lisp_string_type,
+	[AO_LISP_OTHER] = (void *) 0x1,
+	[AO_LISP_ATOM] = &ao_lisp_atom_type,
+	[AO_LISP_BUILTIN] = &ao_lisp_builtin_type,
+	[AO_LISP_FRAME] = &ao_lisp_frame_type,
+	[AO_LISP_LAMBDA] = &ao_lisp_lambda_type,
+	[AO_LISP_STACK] = &ao_lisp_stack_type,
+};
+
+static int
+ao_lisp_mark_ref(const struct ao_lisp_type *type, void **ref)
+{
+	return ao_lisp_mark(type, *ref);
+}
+
+static int
+ao_lisp_poly_mark_ref(ao_poly *p, uint8_t do_note_cons)
+{
+	return ao_lisp_poly_mark(*p, do_note_cons);
+}
+
+#if DBG_MEM_STATS
+int ao_lisp_collects[2];
+int ao_lisp_freed[2];
+int ao_lisp_loops[2];
+#endif
+
+int ao_lisp_last_top;
+
+int
+ao_lisp_collect(uint8_t style)
+{
+	int	i;
+	int	top;
+#if DBG_MEM_STATS
+	int	loops = 0;
+#endif
+#if DBG_MEM
+	struct ao_lisp_record	*mark_record = NULL, *move_record = NULL;
+
+	MDBG_MOVE("collect %d\n", ao_lisp_collects[style]);
+#endif
+
+	/* The first time through, we're doing a full collect */
+	if (ao_lisp_last_top == 0)
+		style = AO_LISP_COLLECT_FULL;
+
+	/* Clear references to all caches */
+	for (i = 0; i < (int) AO_LISP_CACHE; i++)
+		*ao_lisp_cache[i] = NULL;
+	if (style == AO_LISP_COLLECT_FULL) {
+		chunk_low = top = 0;
+	} else {
+		chunk_low = top = ao_lisp_last_top;
+	}
+	for (;;) {
+#if DBG_MEM_STATS
+		loops++;
+#endif
+		MDBG_MOVE("move chunks from %d to %d\n", chunk_low, top);
+		/* Find the sizes of the first chunk of objects to move */
+		reset_chunks();
+		walk(ao_lisp_mark_ref, ao_lisp_poly_mark_ref);
+#if DBG_MEM
+
+		ao_lisp_record_free(mark_record);
+		mark_record = ao_lisp_record_save();
+		if (mark_record && move_record)
+			ao_lisp_record_compare("mark", move_record, mark_record);
+#endif
+
+		DUMP_BUSY();
+
+		/* Find the first moving object */
+		for (i = 0; i < chunk_last; i++) {
+			uint16_t	size = ao_lisp_chunk[i].size;
+
+#if DBG_MEM
+			if (!size)
+				ao_lisp_abort();
+#endif
+
+			if (ao_lisp_chunk[i].old_offset > top)
+				break;
+
+			MDBG_MOVE("chunk %d %d not moving\n",
+				  ao_lisp_chunk[i].old_offset,
+				  ao_lisp_chunk[i].size);
+#if DBG_MEM
+			if (ao_lisp_chunk[i].old_offset != top)
+				ao_lisp_abort();
+#endif
+			top += size;
+		}
+
+		/*
+		 * Limit amount of chunk array used in mapping moves
+		 * to the active region
+		 */
+		chunk_first = i;
+		chunk_low = ao_lisp_chunk[i].old_offset;
+
+		/* Copy all of the objects */
+		for (; i < chunk_last; i++) {
+			uint16_t	size = ao_lisp_chunk[i].size;
+
+#if DBG_MEM
+			if (!size)
+				ao_lisp_abort();
+#endif
+
+			MDBG_MOVE("chunk %d %d -> %d\n",
+				  ao_lisp_chunk[i].old_offset,
+				  size,
+				  top);
+			ao_lisp_chunk[i].new_offset = top;
+
+			memmove(&ao_lisp_pool[top],
+				&ao_lisp_pool[ao_lisp_chunk[i].old_offset],
+				size);
+
+			top += size;
+		}
+
+		if (chunk_first < chunk_last) {
+			/* Relocate all references to the objects */
+			walk(ao_lisp_move, ao_lisp_poly_move);
+
+#if DBG_MEM
+			ao_lisp_record_free(move_record);
+			move_record = ao_lisp_record_save();
+			if (mark_record && move_record)
+				ao_lisp_record_compare("move", mark_record, move_record);
+#endif
+		}
+
+		/* If we ran into the end of the heap, then
+		 * there's no need to keep walking
+		 */
+		if (chunk_last != AO_LISP_NCHUNK)
+			break;
+
+		/* Next loop starts right above this loop */
+		chunk_low = chunk_high;
+	}
+
+#if DBG_MEM_STATS
+	/* Collect stats */
+	++ao_lisp_collects[style];
+	ao_lisp_freed[style] += ao_lisp_top - top;
+	ao_lisp_loops[style] += loops;
+#endif
+
+	ao_lisp_top = top;
+	if (style == AO_LISP_COLLECT_FULL)
+		ao_lisp_last_top = top;
+
+	MDBG_DO(memset(ao_lisp_chunk, '\0', sizeof (ao_lisp_chunk));
+		walk(ao_lisp_mark_ref, ao_lisp_poly_mark_ref));
+
+	return AO_LISP_POOL - ao_lisp_top;
+}
+
+/*
+ * Mark interfaces for objects
+ */
+
+/*
+ * Note a reference to memory and collect information about a few
+ * object sizes at a time
+ */
+
+int
+ao_lisp_mark_memory(const struct ao_lisp_type *type, void *addr)
+{
+	int offset;
+	if (!AO_LISP_IS_POOL(addr))
+		return 1;
+
+	offset = pool_offset(addr);
+	MDBG_MOVE("mark memory %d\n", MDBG_OFFSET(addr));
+	if (busy(ao_lisp_busy, offset)) {
+		MDBG_MOVE("already marked\n");
+		return 1;
+	}
+	mark(ao_lisp_busy, offset);
+	note_chunk(offset, ao_lisp_size(type, addr));
+	return 0;
+}
+
+/*
+ * Mark an object and all that it refereces
+ */
+int
+ao_lisp_mark(const struct ao_lisp_type *type, void *addr)
+{
+	int ret;
+	MDBG_MOVE("mark %d\n", MDBG_OFFSET(addr));
+	MDBG_MOVE_IN();
+	ret = ao_lisp_mark_memory(type, addr);
+	if (!ret) {
+		MDBG_MOVE("mark recurse\n");
+		type->mark(addr);
+	}
+	MDBG_MOVE_OUT();
+	return ret;
+}
+
+/*
+ * Mark an object, unless it is a cons cell and
+ * do_note_cons is set. In that case, just
+ * set a bit in the cons note array; those
+ * will be marked in a separate pass to avoid
+ * deep recursion in the collector
+ */
+int
+ao_lisp_poly_mark(ao_poly p, uint8_t do_note_cons)
+{
+	uint8_t type;
+	void	*addr;
+
+	type = ao_lisp_poly_base_type(p);
+
+	if (type == AO_LISP_INT)
+		return 1;
+
+	addr = ao_lisp_ref(p);
+	if (!AO_LISP_IS_POOL(addr))
+		return 1;
+
+	if (type == AO_LISP_CONS && do_note_cons) {
+		note_cons(pool_offset(addr));
+		return 1;
+	} else {
+		if (type == AO_LISP_OTHER)
+			type = ao_lisp_other_type(addr);
+
+		const struct ao_lisp_type *lisp_type = ao_lisp_types[type];
+#if DBG_MEM
+		if (!lisp_type)
+			ao_lisp_abort();
+#endif
+
+		return ao_lisp_mark(lisp_type, addr);
+	}
+}
+
+/*
+ * Find the current location of an object
+ * based on the original location. For unmoved
+ * objects, this is simple. For moved objects,
+ * go search for it
+ */
+
+static uint16_t
+move_map(uint16_t offset)
+{
+	int		l;
+
+	if (offset < chunk_low || chunk_high <= offset)
+		return offset;
+
+	l = find_chunk(offset);
+
+#if DBG_MEM
+	if (ao_lisp_chunk[l].old_offset != offset)
+		ao_lisp_abort();
+#endif
+	return ao_lisp_chunk[l].new_offset;
+}
+
+int
+ao_lisp_move_memory(const struct ao_lisp_type *type, void **ref)
+{
+	void		*addr = *ref;
+	uint16_t	offset, orig_offset;
+
+	if (!AO_LISP_IS_POOL(addr))
+		return 1;
+
+	(void) type;
+
+	MDBG_MOVE("move memory %d\n", MDBG_OFFSET(addr));
+	orig_offset = pool_offset(addr);
+	offset = move_map(orig_offset);
+	if (offset != orig_offset) {
+		MDBG_MOVE("update ref %d %d -> %d\n",
+			  AO_LISP_IS_POOL(ref) ? MDBG_OFFSET(ref) : -1,
+			  orig_offset, offset);
+		*ref = ao_lisp_pool + offset;
+	}
+	if (busy(ao_lisp_busy, offset)) {
+		MDBG_MOVE("already moved\n");
+		return 1;
+	}
+	mark(ao_lisp_busy, offset);
+	MDBG_DO(ao_lisp_record(type, addr, ao_lisp_size(type, addr)));
+	return 0;
+}
+
+int
+ao_lisp_move(const struct ao_lisp_type *type, void **ref)
+{
+	int ret;
+	MDBG_MOVE("move object %d\n", MDBG_OFFSET(*ref));
+	MDBG_MOVE_IN();
+	ret = ao_lisp_move_memory(type, ref);
+	if (!ret) {
+		MDBG_MOVE("move recurse\n");
+		type->move(*ref);
+	}
+	MDBG_MOVE_OUT();
+	return ret;
+}
+
+int
+ao_lisp_poly_move(ao_poly *ref, uint8_t do_note_cons)
+{
+	uint8_t		type;
+	ao_poly		p = *ref;
+	int		ret;
+	void		*addr;
+	uint16_t	offset, orig_offset;
+	uint8_t		base_type;
+
+	base_type = type = ao_lisp_poly_base_type(p);
+
+	if (type == AO_LISP_INT)
+		return 1;
+
+	addr = ao_lisp_ref(p);
+	if (!AO_LISP_IS_POOL(addr))
+		return 1;
+
+	orig_offset = pool_offset(addr);
+	offset = move_map(orig_offset);
+
+	if (type == AO_LISP_CONS && do_note_cons) {
+		note_cons(orig_offset);
+		ret = 1;
+	} else {
+		if (type == AO_LISP_OTHER)
+			type = ao_lisp_other_type(ao_lisp_pool + offset);
+
+		const struct ao_lisp_type *lisp_type = ao_lisp_types[type];
+#if DBG_MEM
+		if (!lisp_type)
+			ao_lisp_abort();
+#endif
+
+		ret = ao_lisp_move(lisp_type, &addr);
+	}
+
+	/* Re-write the poly value */
+	if (offset != orig_offset) {
+		ao_poly np = ao_lisp_poly(ao_lisp_pool + offset, base_type);
+		MDBG_MOVE("poly %d moved %d -> %d\n",
+			  type, orig_offset, offset);
+		*ref = np;
+	}
+	return ret;
+}
+
+#if DBG_MEM
+void
+ao_lisp_validate(void)
+{
+	chunk_low = 0;
+	memset(ao_lisp_chunk, '\0', sizeof (ao_lisp_chunk));
+	walk(ao_lisp_mark_ref, ao_lisp_poly_mark_ref);
+}
+
+int dbg_allocs;
+
+#endif
+
+void *
+ao_lisp_alloc(int size)
+{
+	void	*addr;
+
+	MDBG_DO(++dbg_allocs);
+	MDBG_DO(if (dbg_validate) ao_lisp_validate());
+	size = ao_lisp_size_round(size);
+	if (AO_LISP_POOL - ao_lisp_top < size &&
+	    ao_lisp_collect(AO_LISP_COLLECT_INCREMENTAL) < size &&
+	    ao_lisp_collect(AO_LISP_COLLECT_FULL) < size)
+	{
+		ao_lisp_error(AO_LISP_OOM, "out of memory");
+		return NULL;
+	}
+	addr = ao_lisp_pool + ao_lisp_top;
+	ao_lisp_top += size;
+	return addr;
+}
+
+void
+ao_lisp_cons_stash(int id, struct ao_lisp_cons *cons)
+{
+	save_cons[id] = cons;
+}
+
+struct ao_lisp_cons *
+ao_lisp_cons_fetch(int id)
+{
+	struct ao_lisp_cons *cons = save_cons[id];
+	save_cons[id] = NULL;
+	return cons;
+}
+
+void
+ao_lisp_poly_stash(int id, ao_poly poly)
+{
+	save_poly[id] = poly;
+}
+
+ao_poly
+ao_lisp_poly_fetch(int id)
+{
+	ao_poly poly = save_poly[id];
+	save_poly[id] = AO_LISP_NIL;
+	return poly;
+}
+
+void
+ao_lisp_string_stash(int id, char *string)
+{
+	save_string[id] = string;
+}
+
+char *
+ao_lisp_string_fetch(int id)
+{
+	char *string = save_string[id];
+	save_string[id] = NULL;
+	return string;
+}
+