From: Keith Packard <keithp@keithp.com>
Date: Mon, 11 Dec 2017 00:52:26 +0000 (-0800)
Subject: altos/scheme: Stash cons across value allocation in compare
X-Git-Tag: 1.8.3~1^2~16
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=bdafb4dfad89d92efec37ed826d5f22e9167e717

altos/scheme: Stash cons across value allocation in compare

Large ints, strings and floats can cause allocation, requiring that
the 'cons' pointer be stashed and retrieved in case it moved.

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

diff --git a/src/scheme/ao_scheme_builtin.c b/src/scheme/ao_scheme_builtin.c
index 6f9e1390..7a590735 100644
--- a/src/scheme/ao_scheme_builtin.c
+++ b/src/scheme/ao_scheme_builtin.c
@@ -319,6 +319,7 @@ ao_scheme_math(struct ao_scheme_cons *orig_cons, enum ao_scheme_builtin_id op)
 
 		if (cons == orig_cons) {
 			ret = car;
+			ao_scheme_cons_stash(0, cons);
 			if (cons->cdr == AO_SCHEME_NIL) {
 				switch (op) {
 				case builtin_minus:
@@ -339,6 +340,7 @@ ao_scheme_math(struct ao_scheme_cons *orig_cons, enum ao_scheme_builtin_id op)
 					break;
 				}
 			}
+			cons = ao_scheme_cons_fetch(0);
 		} else if (ao_scheme_integer_typep(rt) && ao_scheme_integer_typep(ct)) {
 			int32_t	r = ao_scheme_poly_integer(ret);
 			int32_t	c = ao_scheme_poly_integer(car);
@@ -390,7 +392,9 @@ ao_scheme_math(struct ao_scheme_cons *orig_cons, enum ao_scheme_builtin_id op)
 			default:
 				break;
 			}
+			ao_scheme_cons_stash(0, cons);
 			ret = ao_scheme_integer_poly(r);
+			cons = ao_scheme_cons_fetch(0);
 		} else if (ao_scheme_number_typep(rt) && ao_scheme_number_typep(ct)) {
 			float r, c;
 		inexact:
@@ -416,12 +420,18 @@ ao_scheme_math(struct ao_scheme_cons *orig_cons, enum ao_scheme_builtin_id op)
 			default:
 				break;
 			}
+			ao_scheme_cons_stash(0, cons);
 			ret = ao_scheme_float_get(r);
+			cons = ao_scheme_cons_fetch(0);
 		}
-
-		else if (rt == AO_SCHEME_STRING && ct == AO_SCHEME_STRING && op == builtin_plus)
+		else if (rt == AO_SCHEME_STRING && ct == AO_SCHEME_STRING && op == builtin_plus) {
+			ao_scheme_cons_stash(0, cons);
 			ret = ao_scheme_string_poly(ao_scheme_string_cat(ao_scheme_poly_string(ret),
-								     ao_scheme_poly_string(car)));
+									 ao_scheme_poly_string(car)));
+			cons = ao_scheme_cons_fetch(0);
+			if (!ret)
+				return ret;
+		}
 		else
 			return ao_scheme_error(AO_SCHEME_INVALID, "invalid args");
 	}