fix regalloc

+ Had some small issues with ending lifetimes a bit too late

2 files changed, 15 insertions, 18 deletions

diff --git a/src/common.h b/src/common.h
index c690f8f..661220b 100644
--- a/src/common.h
+++ b/src/common.h
@@ -289,6 +289,7 @@ struct ejit_func {
 
 	void *arena;
 	void *direct_call;
+	void *extern_call;
 	size_t size;
 	size_t prio;
 	size_t max_args;
diff --git a/src/compile/compile.c b/src/compile/compile.c
index 22da25a..dac8dfd 100644
--- a/src/compile/compile.c
+++ b/src/compile/compile.c
@@ -2465,39 +2465,35 @@ static void calculate_alive(struct alive *alive, size_t idx,
 		size_t prio, size_t start, size_t end, size_t *rno,
 		void *regs, int (*dead)(void *regs, size_t idx, size_t start))
 {
-	/* single-shot */
+	/* single-shot registers go in the special reserved slot */
 	if (end <= start + 1) {
 		*rno = 0;
+
 		struct alive_slot *a = alive_at(alive, 0);
 		a->cost += prio;
 		return;
 	}
 
+	/* kill registers whose lifetime has ended */
 	long max_cost_idx = -1;
 	size_t max_cost = 0;
 	long counter = 0;
 	foreach_vec(ai, *alive) {
-		struct alive_slot *a = alive_at(alive, ai);
+		/* skip oneshot */
+		if (ai == 0)
+			goto next;
 
-		/* skip reserved slot */
-		if (idx == 0) {
-			counter++;
-			continue;
-		}
+		struct alive_slot *a = alive_at(alive, ai);
+		if (a->r >= 0 && dead(regs, a->r, start))
+			a->r = -1; /* gravestone */
 
 		if (a->r < 0 && a->cost > max_cost) {
 			max_cost = a->cost;
 			max_cost_idx = counter;
 		}
 
+next:
 		counter++;
-
-		/* skip gravestones */
-		if (a->r < 0)
-			continue;
-
-		if (dead(regs, a->r, start))
-			a->r = -1; /* gravestone */
 	}
 
 	/* there's a suitable slot for us */
@@ -2522,7 +2518,7 @@ static void calculate_alive(struct alive *alive, size_t idx,
 static int gpr_dead(void *regs, size_t idx, size_t start)
 {
 	struct gpr_stats *gprs = regs;
-	return gpr_stats_at(gprs, idx)->end < start;
+	return gpr_stats_at(gprs, idx)->end <= start;
 }
 
 static void linear_gpr_alloc(struct ejit_func *f)
@@ -2542,7 +2538,7 @@ static void assign_gprs(struct ejit_func *f)
 	struct alive alive = alive_create(gpr_stats_len(&f->gpr));
 
 	/* special oneshot register class */
-	struct alive_slot a = {.r = 0, .cost = 0, .idx = 0};
+	struct alive_slot a = {.r = -1, .cost = 0, .idx = 0};
 	alive_append(&alive, a);
 
 	foreach_vec(gi, f->gpr) {
@@ -2575,7 +2571,7 @@ static void assign_gprs(struct ejit_func *f)
 static int fpr_dead(void *regs, size_t idx, size_t start)
 {
 	struct fpr_stats *fprs = regs;
-	return fpr_stats_at(fprs, idx)->end < start;
+	return fpr_stats_at(fprs, idx)->end <= start;
 }
 
 static void linear_fpr_alloc(struct ejit_func *f)
@@ -2594,7 +2590,7 @@ static void assign_fprs(struct ejit_func *f)
 	struct alive alive = alive_create(fpr_stats_len(&f->fpr));
 
 	/* special oneshot register class */
-	struct alive_slot a = {.r = 0, .cost = 0, .idx = 0};
+	struct alive_slot a = {.r = -1, .cost = 0, .idx = 0};
 	alive_append(&alive, a);
 
 	foreach_vec(fi, f->fpr) {