[PATCH] openssl: use RB_GC_GUARD instead of volatile

[PATCH] openssl: use RB_GC_GUARD instead of volatile

[Eric Wong]

From doc/extension.rdoc:
>
> Using the RB_GC_GUARD macro is preferable to using the "volatile"
> keyword in C.  RB_GC_GUARD has the following advantages:
>
> 1) the intent of the macro use is clear
>
> 2) RB_GC_GUARD only affects its call site, "volatile" generates some
>    extra code every time the variable is used, hurting optimization.
>
> 3) "volatile" implementations may be buggy/inconsistent in some
>    compilers and architectures. RB_GC_GUARD is customizable for broken
>    systems/compilers without those without negatively affecting other
>    systems.
---
 ext/openssl/ossl_asn1.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/ext/openssl/ossl_asn1.c b/ext/openssl/ossl_asn1.c
index bcd0929..fb7861d 100644
--- a/ext/openssl/ossl_asn1.c
+++ b/ext/openssl/ossl_asn1.c
@@ -1029,7 +1029,7 @@ static VALUE
 ossl_asn1_traverse(VALUE self, VALUE obj)
 {
     unsigned char *p;
-    volatile VALUE tmp;
+    VALUE tmp;
     long len, read = 0, offset = 0;
 
     obj = ossl_to_der_if_possible(obj);
@@ -1037,6 +1037,7 @@ ossl_asn1_traverse(VALUE self, VALUE obj)
     p = (unsigned char *)RSTRING_PTR(tmp);
     len = RSTRING_LEN(tmp);
     ossl_asn1_decode0(&p, len, &offset, 0, 1, &read);
+    RB_GC_GUARD(tmp);
     int_ossl_decode_sanity_check(len, read, offset);
     return Qnil;
 }
@@ -1058,7 +1059,7 @@ ossl_asn1_decode(VALUE self, VALUE obj)
 {
     VALUE ret;
     unsigned char *p;
-    volatile VALUE tmp;
+    VALUE tmp;
     long len, read = 0, offset = 0;
 
     obj = ossl_to_der_if_possible(obj);
@@ -1066,6 +1067,7 @@ ossl_asn1_decode(VALUE self, VALUE obj)
     p = (unsigned char *)RSTRING_PTR(tmp);
     len = RSTRING_LEN(tmp);
     ret = ossl_asn1_decode0(&p, len, &offset, 0, 0, &read);
+    RB_GC_GUARD(tmp);
     int_ossl_decode_sanity_check(len, read, offset);
     return ret;
 }
@@ -1089,7 +1091,7 @@ ossl_asn1_decode_all(VALUE self, VALUE obj)
     VALUE ary, val;
     unsigned char *p;
     long len, tmp_len = 0, read = 0, offset = 0;
-    volatile VALUE tmp;
+    VALUE tmp;
 
     obj = ossl_to_der_if_possible(obj);
     tmp = rb_str_new4(StringValue(obj));
@@ -1104,6 +1106,7 @@ ossl_asn1_decode_all(VALUE self, VALUE obj)
 	read += tmp_read;
 	tmp_len -= tmp_read;
     }
+    RB_GC_GUARD(tmp);
     int_ossl_decode_sanity_check(len, read, offset);
     return ary;
 }
-- 
EW