altos/lisp: Make sure memmove only happens once per object. Other GC fixes

The memmove may be overlapping, so make sure it happens only once by
just checking whether move_size has been set, rather than looking at
ao_lisp_moving; that doesn't get set when moving a noted cons as that
still needs to be walked at a later time.

Fix up the various looping move functions to all use the same
pattern. Atom was busted.

Signed-off-by: Keith Packard <keithp@keithp.com>

5 files changed, 81 insertions, 51 deletions

diff --git a/src/lisp/ao_lisp_atom.c b/src/lisp/ao_lisp_atom.c
index efa4f621..e1d9b082 100644
--- a/src/lisp/ao_lisp_atom.c
+++ b/src/lisp/ao_lisp_atom.c
@@ -46,11 +46,19 @@ static void atom_mark(void *addr)
 static void atom_move(void *addr)
 {
 	struct ao_lisp_atom	*atom = addr;
+	int			ret;
 
 	for (;;) {
-		if (ao_lisp_poly_move(&atom->next, 0))
+		struct ao_lisp_atom *next = ao_lisp_poly_atom(atom->next);
+
+		if (!next)
 			break;
-		atom = ao_lisp_poly_atom(atom->next);
+		ret = ao_lisp_move_memory((void **) &next, atom_size(next));
+		if (next != ao_lisp_poly_atom(atom->next))
+			atom->next = ao_lisp_atom_poly(next);
+		if (ret)
+			break;
+		atom = next;
 	}
 }
 
diff --git a/src/lisp/ao_lisp_cons.c b/src/lisp/ao_lisp_cons.c
index b75ffaa0..c7d8382f 100644
--- a/src/lisp/ao_lisp_cons.c
+++ b/src/lisp/ao_lisp_cons.c
@@ -49,6 +49,8 @@ static void cons_move(void *addr)
 
 		(void) ao_lisp_poly_move(&cons->car, 1);
 		cdr = ao_lisp_poly_cons(cons->cdr);
+		if (!cdr)
+			break;
 		ret = ao_lisp_move_memory((void **) &cdr, sizeof (struct ao_lisp_cons));
 		if (cdr != ao_lisp_poly_cons(cons->cdr))
 			cons->cdr = ao_lisp_cons_poly(cdr);
@@ -64,20 +66,29 @@ const struct ao_lisp_type ao_lisp_cons_type = {
 	.move = cons_move,
 };
 
+static ao_poly	cons_car;
+static struct ao_lisp_cons *cons_cdr;
+static int been_here;
+
 struct ao_lisp_cons *
 ao_lisp_cons_cons(ao_poly car, struct ao_lisp_cons *cdr)
 {
 	struct ao_lisp_cons	*cons;
 
-	ao_lisp_root_add(&ao_lisp_cons_type, &cdr);
-	ao_lisp_root_poly_add(&car);
+	if (!been_here) {
+		ao_lisp_root_add(&ao_lisp_cons_type, &cons_cdr);
+		ao_lisp_root_poly_add(&cons_car);
+		been_here = 1;
+	}
+	cons_car = car;
+	cons_cdr = cdr;
 	cons = ao_lisp_alloc(sizeof (struct ao_lisp_cons));
-	ao_lisp_root_clear(&car);
-	ao_lisp_root_clear(&cdr);
 	if (!cons)
 		return NULL;
-	cons->car = car;
-	cons->cdr = ao_lisp_cons_poly(cdr);
+	cons->car = cons_car;
+	cons->cdr = ao_lisp_cons_poly(cons_cdr);
+	cons_car = AO_LISP_NIL;
+	cons_cdr = NULL;
 	return cons;
 }
 
diff --git a/src/lisp/ao_lisp_eval.c b/src/lisp/ao_lisp_eval.c
index ae2436b8..1c929869 100644
--- a/src/lisp/ao_lisp_eval.c
+++ b/src/lisp/ao_lisp_eval.c
@@ -32,6 +32,7 @@ stack_mark(void *addr)
 		ao_lisp_poly_mark(stack->values, 0);
 		/* no need to mark values_tail */
 		ao_lisp_poly_mark(stack->frame, 0);
+		ao_lisp_poly_mark(stack->list, 0);
 		stack = ao_lisp_poly_stack(stack->prev);
 		if (ao_lisp_mark_memory(stack, sizeof (struct ao_lisp_stack)))
 			break;
@@ -47,12 +48,15 @@ stack_move(void *addr)
 
 	while (stack) {
 		struct ao_lisp_stack	*prev;
-		int	ret;
+		int			ret;
 		(void) ao_lisp_poly_move(&stack->sexprs, 0);
 		(void) ao_lisp_poly_move(&stack->values, 0);
 		(void) ao_lisp_poly_move(&stack->values_tail, 0);
 		(void) ao_lisp_poly_move(&stack->frame, 0);
+		(void) ao_lisp_poly_move(&stack->list, 0);
 		prev = ao_lisp_poly_stack(stack->prev);
+		if (!prev)
+			break;
 		ret = ao_lisp_move_memory((void **) &prev,
 					  sizeof (struct ao_lisp_stack));
 		if (prev != ao_lisp_poly_stack(stack->prev))
diff --git a/src/lisp/ao_lisp_frame.c b/src/lisp/ao_lisp_frame.c
index 90344719..082860ee 100644
--- a/src/lisp/ao_lisp_frame.c
+++ b/src/lisp/ao_lisp_frame.c
@@ -83,9 +83,9 @@ frame_move(void *addr)
 			ao_lisp_poly_move(&v->val, 0);
 		}
 		next = ao_lisp_poly_frame(frame->next);
-		ret = 1;
-		if (next)
-			ret = ao_lisp_move_memory((void **) &next, frame_size(next));
+		if (!next)
+			break;
+		ret = ao_lisp_move_memory((void **) &next, frame_size(next));
 		if (next != ao_lisp_poly_frame(frame->next))
 			frame->next = ao_lisp_frame_poly(next);
 		if (ret)
diff --git a/src/lisp/ao_lisp_mem.c b/src/lisp/ao_lisp_mem.c
index 1fb1b459..31ee9e1e 100644
--- a/src/lisp/ao_lisp_mem.c
+++ b/src/lisp/ao_lisp_mem.c
@@ -36,22 +36,20 @@ uint8_t	ao_lisp_pool[AO_LISP_POOL] __attribute__((aligned(4)));
 #endif
 
 #if 0
+#include <assert.h>
 #define MDBG_INCLUDE
-#define MDBG_DUMP	1
-#define MDBG_MOVE	0
+#if 1
+#define MDBG_MOVE(...) do { int d; for (d = 0; d < move_depth; d++) printf ("  "); printf(__VA_ARGS__); } while (0)
+#endif
 #define MDBG_OFFSET(a)	((int) ((uint8_t *) (a) - ao_lisp_pool))
 #define MDBG(...) printf(__VA_ARGS__)
 #define MDBG_DO(a)	a
-static int move_dump = MDBG_MOVE;
 static int move_depth;
-#define MDBG_RESET() (move_depth = 0)
-#define MDBG_MOVE(...) do { if(move_dump) { int d; for (d = 0; d < move_depth; d++) printf ("  "); printf(__VA_ARGS__); } } while (0)
 #define MDBG_MOVE_IN()	(move_depth++)
-#define MDBG_MOVE_OUT()	(move_depth--)
+#define MDBG_MOVE_OUT()	(assert(--move_depth >= 0))
 #else
 #define MDBG(...)
 #define MDBG_DO(a)
-#define MDBG_RESET()
 #define MDBG_MOVE(...)
 #define MDBG_MOVE_IN()
 #define MDBG_MOVE_OUT()
@@ -68,10 +66,12 @@ struct ao_lisp_root {
 
 static struct ao_lisp_root	ao_lisp_root[AO_LISP_ROOT];
 
-static uint8_t	ao_lisp_busy[AO_LISP_POOL / 32];
-static uint8_t	ao_lisp_moving[AO_LISP_POOL / 32];
-static uint8_t	ao_lisp_cons_note[AO_LISP_POOL / 32];
-static uint8_t	ao_lisp_cons_last[AO_LISP_POOL / 32];
+#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_moving[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;
@@ -167,9 +167,9 @@ busy_object(uint8_t *tag, void *addr) {
 static void
 note_cons(void *addr)
 {
-	MDBG_MOVE("note cons %d\n", MDBG_OFFSET(addr));
 	if (AO_LISP_IS_POOL(addr)) {
 		int	offset = (uint8_t *) addr - ao_lisp_pool;
+		MDBG_MOVE("note cons %d\n", MDBG_OFFSET(addr));
 		ao_lisp_cons_noted = 1;
 		mark(ao_lisp_cons_note, offset);
 	}
@@ -180,9 +180,9 @@ note_cons(void *addr)
  */
 
 static void
-walk_all(uint8_t *tag,
-	 int (*visit_addr)(const struct ao_lisp_type *type, void **addr),
-	 int (*visit_poly)(ao_poly *p, uint8_t do_note_cons))
+walk(uint8_t *tag,
+     int (*visit_addr)(const struct ao_lisp_type *type, void **addr),
+     int (*visit_poly)(ao_poly *p, uint8_t do_note_cons))
 {
 	int i;
 
@@ -193,13 +193,13 @@ walk_all(uint8_t *tag,
 		if (ao_lisp_root[i].type) {
 			void **a = ao_lisp_root[i].addr, *v;
 			if (a && (v = *a)) {
-				MDBG("root %d\n", MDBG_OFFSET(v));
+				MDBG("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("root 0x%04x\n", p);
+				MDBG("root poly %d\n", MDBG_OFFSET(ao_lisp_ref(p)));
 				visit_poly(a, 0);
 			}
 		}
@@ -211,7 +211,7 @@ walk_all(uint8_t *tag,
 		for (i = 0; i < AO_LISP_POOL; i += 4) {
 			if (busy(ao_lisp_cons_last, i)) {
 				void *v = ao_lisp_pool + i;
-				MDBG("cons %d\n", MDBG_OFFSET(v));
+				MDBG("root cons %d\n", MDBG_OFFSET(v));
 				visit_addr(&ao_lisp_cons_type, &v);
 			}
 		}
@@ -221,12 +221,6 @@ walk_all(uint8_t *tag,
 static void	*move_old, *move_new;
 static int	move_size;
 
-static void
-move_object(void)
-{
-	walk_all(ao_lisp_moving, ao_lisp_move, ao_lisp_poly_move);
-}
-
 #if MDBG_DUMP
 static void
 dump_busy(void)
@@ -273,12 +267,6 @@ ao_lisp_poly_mark_ref(ao_poly *p, uint8_t do_note_cons)
 	return ao_lisp_poly_mark(*p, do_note_cons);
 }
 
-static void
-ao_lisp_mark_busy(void)
-{
-	walk_all(ao_lisp_busy, ao_lisp_mark_ref, ao_lisp_poly_mark_ref);
-}
-
 void
 ao_lisp_collect(void)
 {
@@ -287,7 +275,7 @@ ao_lisp_collect(void)
 
 	MDBG("collect\n");
 	/* Mark */
-	ao_lisp_mark_busy();
+	walk(ao_lisp_busy, ao_lisp_mark_ref, ao_lisp_poly_mark_ref);
 
 	DUMP_BUSY();
 	/* Compact */
@@ -300,10 +288,11 @@ ao_lisp_collect(void)
 	while(i < ao_lisp_top) {
 		if (busy(ao_lisp_busy, i)) {
 			MDBG("busy %d -> %d\n", i, top);
+			MDBG_MOVE_IN();
 			move_old = &ao_lisp_pool[i];
 			move_new = &ao_lisp_pool[top];
 			move_size = 0;
-			move_object();
+			walk(ao_lisp_moving, ao_lisp_move, ao_lisp_poly_move);
 			MDBG("\tbusy size %d\n", move_size);
 			if (move_size == 0)
 				ao_lisp_abort();
@@ -318,6 +307,7 @@ ao_lisp_collect(void)
 #if MDBG_MOVE
 			DUMP_BUSY();
 #endif
+			MDBG_MOVE_OUT();
 		} else {
 			i += 4;
 		}
@@ -331,9 +321,15 @@ ao_lisp_mark(const struct ao_lisp_type *type, void *addr)
 {
 	if (!addr)
 		return 1;
-	if (mark_object(ao_lisp_busy, addr, type->size(addr)))
+	MDBG_MOVE_IN();
+	MDBG_MOVE("mark %d\n", MDBG_OFFSET(addr));
+	if (mark_object(ao_lisp_busy, addr, type->size(addr))) {
+		MDBG_MOVE("already marked\n");
+		MDBG_MOVE_OUT();
 		return 1;
+	}
 	type->mark(addr);
+	MDBG_MOVE_OUT();
 	return 0;
 }
 
@@ -345,6 +341,7 @@ ao_lisp_poly_mark(ao_poly p, uint8_t do_note_cons)
 	if (!p)
 		return 1;
 	if (type == AO_LISP_CONS && do_note_cons) {
+		MDBG_MOVE("note cons %d\n", MDBG_OFFSET(ao_lisp_ref(p)));
 		note_cons(ao_lisp_ref(p));
 		return 0;
 	} else {
@@ -371,7 +368,7 @@ void *
 ao_lisp_move_map(void *addr)
 {
 	if (addr == move_old) {
-		if (busy_object(ao_lisp_moving, addr))
+		if (move_size != 0)
 			return move_new;
 	}
 	return addr;
@@ -382,7 +379,13 @@ check_move(void *addr, int size)
 {
 	if (addr == move_old) {
 		MDBG_MOVE("mapping %d -> %d\n", MDBG_OFFSET(addr), MDBG_OFFSET(move_new));
-		if (!busy_object(ao_lisp_moving, addr)) {
+		if (move_size && move_size != ((size + 3) & ~3))
+			ao_lisp_abort();
+
+		/* Only copy the object once, otherwise we may
+		 * smash stuff
+		 */
+		if (move_size == 0) {
 			MDBG_MOVE("  copy %d\n", size);
 			memmove(move_new, move_old, size);
 			move_size = (size + 3) & ~3;
@@ -397,7 +400,7 @@ ao_lisp_move(const struct ao_lisp_type *type, void **ref)
 {
 	void		*addr = *ref;
 	uint8_t		*a = addr;
-	int		size = type->size(addr);
+	int		size = type->size(ao_lisp_move_map(addr));
 
 	if (!addr)
 		return 1;
@@ -462,9 +465,13 @@ ao_lisp_poly_move(ao_poly *ref, uint8_t do_note_cons)
 
 	type = ao_lisp_poly_base_type(p);
 	addr = ao_lisp_ref(p);
+
+	if ((uint8_t *) addr < ao_lisp_pool || ao_lisp_pool + AO_LISP_POOL <= (uint8_t*) addr)
+		return 1;
+
 	if (type == AO_LISP_CONS && do_note_cons) {
-		note_cons(addr);
 		addr = check_move(addr, sizeof (struct ao_lisp_cons));
+		note_cons(addr);
 		ret = 1;
 	} else {
 
@@ -482,8 +489,8 @@ ao_lisp_poly_move(ao_poly *ref, uint8_t do_note_cons)
 
 	if (addr != ao_lisp_ref(p)) {
 		ao_poly np = ao_lisp_poly(addr, p & AO_LISP_TYPE_MASK);
-		MDBG("poly %d moved %04x -> %04x\n",
-		    type, p, np);
+		MDBG("poly %d moved %d -> %d\n",
+		     type, MDBG_OFFSET(ao_lisp_ref(p)), MDBG_OFFSET(ao_lisp_ref(np)));
 		*ref = np;
 	}
 	return ret;