Make the critical level an enum

Author: nobu

internal/error.h

@@ -241,4 +241,11 @@ rb_typeddata_is_instance_of_inline(VALUE obj, const rb_data_type_t *data_type)
     return RB_TYPE_P(obj, T_DATA) && RTYPEDDATA_P(obj) && (RTYPEDDATA_TYPE(obj) == data_type);
 }
 
+typedef enum {
+    rb_stack_overflow_prevention = 0, // VM stack overflow or about to machine stack overflow
+    rb_stack_overflow_signal = 1, // machine stack overflow but may be recoverable
+    rb_stack_overflow_fatal = 2, // fatal machine stack overflow
+} ruby_stack_overflow_critical_level;
+NORETURN(void rb_ec_stack_overflow(struct rb_execution_context_struct *ec, ruby_stack_overflow_critical_level crit));
+
 #endif /* INTERNAL_ERROR_H */

signal.c

@@ -760,7 +760,6 @@ static const char *received_signal;
 #endif
 
 #if defined(USE_SIGALTSTACK) || defined(_WIN32)
-NORETURN(void rb_ec_stack_overflow(rb_execution_context_t *ec, int crit));
 # if defined __HAIKU__
 #   define USE_UCONTEXT_REG 1
 # elif !(defined(HAVE_UCONTEXT_H) && (defined __i386__ || defined __x86_64__ || defined __amd64__))
@@ -846,18 +845,21 @@ check_stack_overflow(int sig, const uintptr_t addr, const ucontext_t *ctx)
     if (sp_page == fault_page || sp_page == fault_page + 1 ||
         (sp_page <= fault_page && fault_page <= bp_page)) {
         rb_execution_context_t *ec = GET_EC();
-        int crit = FALSE;
+        ruby_stack_overflow_critical_level crit = rb_stack_overflow_signal;
         int uplevel = roomof(pagesize, sizeof(*ec->tag)) / 2; /* XXX: heuristic */
         while ((uintptr_t)ec->tag->buf / pagesize <= fault_page + 1) {
             /* drop the last tag if it is close to the fault,
              * otherwise it can cause stack overflow again at the same
              * place. */
-            if ((crit = (!ec->tag->prev || !--uplevel)) != FALSE) break;
+            if (!ec->tag->prev || !--uplevel) {
+                crit = rb_stack_overflow_fatal;
+                break;
+            }
             rb_vm_tag_jmpbuf_deinit(&ec->tag->buf);
             ec->tag = ec->tag->prev;
         }
         reset_sigmask(sig);
-        rb_ec_stack_overflow(ec, crit + 1);
+        rb_ec_stack_overflow(ec, crit);
     }
 }
 # else

vm_insnhelper.c

@@ -79,24 +79,18 @@ vm_stackoverflow(void)
     ec_stack_overflow(GET_EC(), TRUE);
 }
 
-NORETURN(void rb_ec_stack_overflow(rb_execution_context_t *ec, int crit));
-/* critical level
- * 0: VM stack overflow or about to machine stack overflow
- * 1: machine stack overflow but may be recoverable
- * 2: fatal machine stack overflow
- */
 void
-rb_ec_stack_overflow(rb_execution_context_t *ec, int crit)
+rb_ec_stack_overflow(rb_execution_context_t *ec, ruby_stack_overflow_critical_level crit)
 {
     if (rb_during_gc()) {
         rb_bug("system stack overflow during GC. Faulty native extension?");
     }
-    if (crit > 1) {
+    if (crit >= rb_stack_overflow_fatal) {
         ec->raised_flag = RAISED_STACKOVERFLOW;
         ec->errinfo = rb_ec_vm_ptr(ec)->special_exceptions[ruby_error_stackfatal];
         EC_JUMP_TAG(ec, TAG_RAISE);
     }
-    ec_stack_overflow(ec, crit == 0);
+    ec_stack_overflow(ec, crit < rb_stack_overflow_signal);
 }
 
 static inline void stack_check(rb_execution_context_t *ec);