Enhance OP_RESCUE to take B operand fas matching exception; ref #3487

include/mruby/opcode.h

@@ -82,7 +82,8 @@ enum {
   OP_JMPIF,/*     A sBx   if R(A) pc+=sBx                                 */
   OP_JMPNOT,/*    A sBx   if !R(A) pc+=sBx                                */
   OP_ONERR,/*     sBx     rescue_push(pc+sBx)                             */
-  OP_RESCUE,/*    A B     R(A) := exc; R(B) := matched (ignore if A/B=0)  */
+  OP_RESCUE,/*    A B C   if A (if C exc=R(A) else R(A) := exc);
+                          if B R(B) := exc.isa?(R(B)); clear(exc)         */
   OP_POPERR,/*    A       A.times{rescue_pop()}                           */
   OP_RAISE,/*     A       raise(R(A))                                     */
   OP_EPUSH,/*     Bx      ensure_push(SEQ[Bx])                            */

mrbgems/mruby-compiler/core/codegen.c

@@ -1294,7 +1294,7 @@ codegen(codegen_scope *s, node *tree, int val)
         node *n2 = tree->car;
         int exc = cursp();
 
-        genop(s, MKOP_AB(OP_RESCUE, exc, 0));
+        genop(s, MKOP_ABC(OP_RESCUE, exc, 0, 0));
         push();
         while (n2) {
           node *n3 = n2->car;
@@ -1788,7 +1788,11 @@ codegen(codegen_scope *s, node *tree, int val)
         genop(s, MKOP_A(OP_POPERR, 1));
         noexc = genop(s, MKOP_Bx(OP_JMP, 0));
         dispatch(s, onerr);
+<<<<<<< HEAD
         genop(s, MKOP_AB(OP_RESCUE, exc, 0));
+=======
+        genop(s, MKOP_ABC(OP_RESCUE, exc, 0, 0));
+>>>>>>> 55d89bd... Enhance OP_RESCUE to take B operand fas matching exception; ref #3487
         genop(s, MKOP_A(OP_LOADF, exc));
         dispatch(s, noexc);
         loop_pop(s, NOVAL);

src/codedump.c

@@ -408,8 +408,22 @@ codedump(mrb_state *mrb, mrb_irep *irep)
       printf("OP_ONERR\t%03d\n", i+GETARG_sBx(c));
       break;
     case OP_RESCUE:
-      printf("OP_RESCUE\tR%d\t\t", GETARG_A(c));
-      print_lv(mrb, irep, c, RA);
+      {
+        int a = GETARG_A(c);
+        int b = GETARG_B(c);
+        int cnt = GETARG_C(c);
+
+        if (b == 0) {
+          printf("OP_RESCUE\tR%d\t\t%s", a, cnt ? "cont" : "");
+          print_lv(mrb, irep, c, RA);
+          break;
+        }
+        else {
+          printf("OP_RESCUE\tR%d\tR%d\t%s", a, b, cnt ? "cont" : "");
+          print_lv(mrb, irep, c, RAB);
+          break;
+        }
+      }
       break;
     case OP_RAISE:
       printf("OP_RAISE\tR%d\t\t", GETARG_A(c));

src/vm.c

@@ -1083,7 +1083,31 @@ RETRY_TRY_BLOCK:
 
     CASE(OP_RESCUE) {
       /* A      R(A) := exc; clear(exc) */
-      SET_OBJ_VALUE(regs[GETARG_A(i)], mrb->exc);
+      /* B      R(B) := matched (bool) */
+      int b = GETARG_B(i);
+      mrb_value exc = mrb_obj_value(mrb->exc);
+
+      if (b != 0) {
+        mrb_value e = regs[b];
+        struct RClass *ec;
+
+        switch (mrb_type(e)) {
+        case MRB_TT_CLASS:
+        case MRB_TT_MODULE:
+          break;
+        default:
+          mrb_raise(mrb, E_TYPE_ERROR, "class or module required for rescue clause");
+          break;
+        }
+        ec = mrb_class_ptr(e);
+        if (mrb_obj_is_kind_of(mrb, exc, ec)) {
+          regs[b] = mrb_true_value();
+        }
+        else {
+          regs[b] = mrb_false_value();
+        }
+      }
+      regs[GETARG_A(i)] = exc;
       mrb->exc = 0;
       NEXT;
     }