示例#1
0
文件: exec.c 项目: strcp/implDBT2
void exec_operations(GSList *op_list) {
	struct operation *op;
	enum op_stats stats;

	if (op_list == NULL)
		return;

	lock_s_table = g_hash_table_new(g_str_hash, g_str_equal);
	lock_x_table = g_hash_table_new(g_str_hash, g_str_equal);
	wait_table = g_hash_table_new(g_str_hash, g_str_equal);
	aborted_transaction_list = NULL;

	int i = 0;
	while ((i < g_slist_length(op_list)) || (g_hash_table_size(wait_table) > 0)) {
		exec_waiting_operations();
		if (i < g_slist_length(op_list)) {
			op = g_slist_nth_data(op_list, i);
			if (did_aborted(op)) {
				i++;
				continue;
			}
			printf("EXEC: ");
			dump_operation(op);
			stats = operation_status(op);
			if (stats == OP_WAIT)
				add_transaction_to_wait(op);
			else if (stats != OP_OK) {
				printf("ERROR: ");
				dump_operation(op);
				abort_transaction(op);
			}
			i++;
		}
		check_deadlocks();
#ifdef DEBUG
		dump_wait_table();
		dump_lock_x_table();
		dump_lock_s_table();
#endif
	}

#ifdef DEBUG
	dump_lock_s_table();
	dump_lock_x_table();
	dump_wait_table();
	dump_unlocked_list();
	dump_aborted_list();
#endif

	if ((g_hash_table_size(lock_x_table) > 0) ||
			(g_hash_table_size(lock_s_table) > 0) ||
			(g_hash_table_size(wait_table) > 0))
		printf("ERROR!\n");

	g_hash_table_destroy(lock_s_table);
	g_hash_table_destroy(lock_x_table);
	g_hash_table_destroy(wait_table);
	g_slist_free(unlocked_transaction_list);
	g_slist_free(aborted_transaction_list);
}
示例#2
0
文件: dnp_sim2.c 项目: Firstyear/ds
void apply_operation (Entry_State *entry, Operation *op)
{
	switch (op->type)
	{
		case OP_ADD_VALUE:		apply_add_operation (entry, op);
								break;
			
		case OP_DELETE_VALUE:	apply_value_delete_operation (entry, op);
								break;
		
		case OP_DELETE_ATTR:	apply_attr_delete_operation (entry, op);
								break;
				
		case OP_RENAME_ENTRY:	apply_rename_operation (entry, op);
								break;
	}

	if (sim.verbose)
	{	
		fprintf (sim.fout, "operation: ");
		dump_operation (op);
		fprintf (sim.fout, "\n");
		dump_entry_state (entry);
	}
}
示例#3
0
文件: exec.c 项目: strcp/implDBT2
static void dump_table_list(gpointer key, gpointer value, gpointer userdata)
{
	struct operation *op;
	char *table_type;

	if (key == NULL)
		return;

	GSList *transactions = (GSList *)value;
	if (transactions == NULL)
		return;

	table_type = (char *)userdata;

	printf("\t%s:\n", key);
	for (int i = 0; i < g_slist_length(transactions); i++) {
		if (g_strcmp0(table_type, "wait_table") == 0) {
			op = (struct operation *)g_slist_nth_data(transactions, i);
			if (op != NULL) {
				printf("\t");
				dump_operation(op);
			}
		}
		else {
			int *t = (int *)g_slist_nth_data(transactions, i);
			printf("\t\t%d\n", *t);
		}
	}
}
示例#4
0
文件: bytecode.c 项目: 40a/jq
static void dump_code(int indent, struct bytecode* bc) {
  int pc = 0;
  while (pc < bc->codelen) {
    printf("%*s", indent, "");
    dump_operation(bc, bc->code + pc);
    printf("\n");
    pc += bytecode_operation_length(bc->code + pc);
  }
}
示例#5
0
void dump_codeblock(CodeBlock *cb)
{
  printf("Codeblock '%s'\n", cb->label);
  printf("  #operations: %d\n", cb->nops);

  int i = 0;
  while (i < cb->nops) {
    printf(" %3d: ", i);
    dump_operation(&cb->code[i++]);
  }
}
示例#6
0
文件: dnp_sim2.c 项目: Firstyear/ds
void dump_operations (Operation *ops, int op_count, int *order)
{
	int index;
	int i;

	for (i = 0; i < op_count; i ++)
	{
		if (order == NULL)	/* current order */
			index = i;
		else
			index = order [i];

		dump_operation (&ops[index]);
	}

	fprintf (sim.fout, "\n");
}
示例#7
0
文件: exec.c 项目: strcp/implDBT2
static void add_transaction_to_wait(struct operation *op) {
	if (op == NULL)
		return;

	char *strtrans = g_strdup_printf("%d", op->transaction);
	if (strtrans == NULL)
		return;

#ifdef DEBUG
	printf("ADDING TO WAIT: ");
	dump_operation(op);
#endif

	GSList *op_list = g_hash_table_lookup(wait_table, strtrans);
	op_list = g_slist_append(op_list, op);
	g_hash_table_insert(wait_table, strtrans, op_list);

	// Para ser checado depois pelo analisador de deadlocks.
	if ((op->cmd == CMD_LOCK_X) || (op->cmd == CMD_LOCK_S))
		lock_waiting_list = g_slist_append(lock_waiting_list, op);
}
示例#8
0
int main(int argc, char** argv) {

  if (argc <= 1) {
    return usage(argv[0], EXIT_FAILURE);
  }

  if (strncmp(argv[1], "-h", 3) == 0 || strncmp(argv[1], "--help", 7) == 0) {
    return usage(argv[0], EXIT_SUCCESS);
  }

  FILE* file = fopen(argv[1], "r");

  operation_t* op = operation_init(OP_INVENTORY);

  while (read_operation(file, op) > 0) {
    dump_operation(op);
    operation_reset(op);
  }

  operation_delete(op);

  return EXIT_SUCCESS;
}
示例#9
0
文件: exec.c 项目: strcp/implDBT2
static void exec_waiting_list(gpointer key, gpointer value, gpointer userdata) {
	struct operation *op;
	enum op_stats stats;

	if (key == NULL)
		return;

	GSList *transactions = (GSList *)value;

	for (int i = 0; i < g_slist_length(transactions); i++) {
		op = (struct operation *)g_slist_nth_data(transactions, i);
		stats = operation_status(op);
		if (stats == OP_OK) {
			printf("EXWO: ");
			dump_operation(op);
			remove_transaction_from_wait(op);
		}
//		else {
//			printf("EXWN: ");
//			dump_operation(op);
//		}
	}
}
示例#10
0
jv jq_next(jq_state *jq) {
  jv cfunc_input[MAX_CFUNCTION_ARGS];

  jv_nomem_handler(jq->nomem_handler, jq->nomem_handler_data);

  uint16_t* pc = stack_restore(jq);
  assert(pc);

  int backtracking = !jq->initial_execution;
  jq->initial_execution = 0;
  while (1) {
    uint16_t opcode = *pc;

    if (jq->debug_trace_enabled) {
      dump_operation(frame_current(jq)->bc, pc);
      printf("\t");
      const struct opcode_description* opdesc = opcode_describe(opcode);
      stack_ptr param = 0;
      if (!backtracking) {
        int stack_in = opdesc->stack_in;
        if (stack_in == -1) stack_in = pc[1];
        int i;
        for (i=0; i<stack_in; i++) {
          if (i == 0) {
            param = jq->stk_top;
          } else {
            printf(" | ");
            param = *stack_block_next(&jq->stk, param);
          }
          if (!param) break;
          jv_dump(jv_copy(*(jv*)stack_block(&jq->stk, param)), 0);
          //printf("<%d>", jv_get_refcnt(param->val));
          //printf(" -- ");
          //jv_dump(jv_copy(jq->path), 0);
        }
      } else {
        printf("\t<backtracking>");
      }

      printf("\n");
    }

    if (backtracking) {
      opcode = ON_BACKTRACK(opcode);
      backtracking = 0;
    }
    pc++;

    switch (opcode) {
    default: assert(0 && "invalid instruction");

    case LOADK: {
      jv v = jv_array_get(jv_copy(frame_current(jq)->bc->constants), *pc++);
      assert(jv_is_valid(v));
      jv_free(stack_pop(jq));
      stack_push(jq, v);
      break;
    }

    case DUP: {
      jv v = stack_pop(jq);
      stack_push(jq, jv_copy(v));
      stack_push(jq, v);
      break;
    }

    case DUP2: {
      jv keep = stack_pop(jq);
      jv v = stack_pop(jq);
      stack_push(jq, jv_copy(v));
      stack_push(jq, keep);
      stack_push(jq, v);
      break;
    }

    case SUBEXP_BEGIN: {
      jv v = stack_pop(jq);
      stack_push(jq, jv_copy(v));
      stack_push(jq, v);
      jq->subexp_nest++;
      break;
    }

    case SUBEXP_END: {
      assert(jq->subexp_nest > 0);
      jq->subexp_nest--;
      jv a = stack_pop(jq);
      jv b = stack_pop(jq);
      stack_push(jq, a);
      stack_push(jq, b);
      break;
    }
      
    case POP: {
      jv_free(stack_pop(jq));
      break;
    }

    case APPEND: {
      jv v = stack_pop(jq);
      uint16_t level = *pc++;
      uint16_t vidx = *pc++;
      jv* var = frame_local_var(jq, vidx, level);
      assert(jv_get_kind(*var) == JV_KIND_ARRAY);
      *var = jv_array_append(*var, v);
      break;
    }

    case INSERT: {
      jv stktop = stack_pop(jq);
      jv v = stack_pop(jq);
      jv k = stack_pop(jq);
      jv objv = stack_pop(jq);
      assert(jv_get_kind(objv) == JV_KIND_OBJECT);
      if (jv_get_kind(k) == JV_KIND_STRING) {
        stack_push(jq, jv_object_set(objv, k, v));
        stack_push(jq, stktop);
      } else {
        print_error(jq, jv_invalid_with_msg(jv_string_fmt("Cannot use %s as object key",
                                                          jv_kind_name(jv_get_kind(k)))));
        jv_free(stktop);
        jv_free(v);
        jv_free(k);
        jv_free(objv);
        goto do_backtrack;
      }
      break;
    }

    case ON_BACKTRACK(RANGE):
    case RANGE: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      jv* var = frame_local_var(jq, v, level);
      jv max = stack_pop(jq);
      if (jv_get_kind(*var) != JV_KIND_NUMBER ||
          jv_get_kind(max) != JV_KIND_NUMBER) {
        print_error(jq, jv_invalid_with_msg(jv_string_fmt("Range bounds must be numeric")));
        jv_free(max);
        goto do_backtrack;
      } else if (jv_number_value(jv_copy(*var)) >= jv_number_value(jv_copy(max))) {
        /* finished iterating */
        goto do_backtrack;
      } else {
        jv curr = jv_copy(*var);
        *var = jv_number(jv_number_value(*var) + 1);

        struct stack_pos spos = stack_get_pos(jq);
        stack_push(jq, jv_copy(max));
        stack_save(jq, pc - 3, spos);

        stack_push(jq, curr);
      }
      break;
    }

      // FIXME: loadv/storev may do too much copying/freeing
    case LOADV: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      jv* var = frame_local_var(jq, v, level);
      if (jq->debug_trace_enabled) {
        printf("V%d = ", v);
        jv_dump(jv_copy(*var), 0);
        printf("\n");
      }
      jv_free(stack_pop(jq));
      stack_push(jq, jv_copy(*var));
      break;
    }

      // Does a load but replaces the variable with null
    case LOADVN: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      jv* var = frame_local_var(jq, v, level);
      if (jq->debug_trace_enabled) {
        printf("V%d = ", v);
        jv_dump(jv_copy(*var), 0);
        printf("\n");
      }
      jv_free(stack_pop(jq));
      stack_push(jq, *var);
      *var = jv_null();
      break;
    }

    case STOREV: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      jv* var = frame_local_var(jq, v, level);
      jv val = stack_pop(jq);
      if (jq->debug_trace_enabled) {
        printf("V%d = ", v);
        jv_dump(jv_copy(val), 0);
        printf("\n");
      }
      jv_free(*var);
      *var = val;
      break;
    }

    case PATH_BEGIN: {
      jv v = stack_pop(jq);
      stack_push(jq, jq->path);

      stack_save(jq, pc - 1, stack_get_pos(jq));

      stack_push(jq, jv_number(jq->subexp_nest));
      stack_push(jq, v);

      jq->path = jv_array();
      jq->subexp_nest = 0;
      break;
    }

    case PATH_END: {
      jv v = stack_pop(jq);
      jv_free(v); // discard value, only keep path

      int old_subexp_nest = (int)jv_number_value(stack_pop(jq));

      jv path = jq->path;
      jq->path = stack_pop(jq);

      struct stack_pos spos = stack_get_pos(jq);
      stack_push(jq, jv_copy(path));
      stack_save(jq, pc - 1, spos);

      stack_push(jq, path);
      jq->subexp_nest = old_subexp_nest;
      break;
    }

    case ON_BACKTRACK(PATH_BEGIN):
    case ON_BACKTRACK(PATH_END): {
      jv_free(jq->path);
      jq->path = stack_pop(jq);
      goto do_backtrack;
    }

    case INDEX:
    case INDEX_OPT: {
      jv t = stack_pop(jq);
      jv k = stack_pop(jq);
      path_append(jq, jv_copy(k));
      jv v = jv_get(t, k);
      if (jv_is_valid(v)) {
        stack_push(jq, v);
      } else {
        if (opcode == INDEX)
          print_error(jq, v);
        else
          jv_free(v);
        goto do_backtrack;
      }
      break;
    }


    case JUMP: {
      uint16_t offset = *pc++;
      pc += offset;
      break;
    }

    case JUMP_F: {
      uint16_t offset = *pc++;
      jv t = stack_pop(jq);
      jv_kind kind = jv_get_kind(t);
      if (kind == JV_KIND_FALSE || kind == JV_KIND_NULL) {
        pc += offset;
      }
      stack_push(jq, t); // FIXME do this better
      break;
    }

    case EACH: 
    case EACH_OPT: 
      stack_push(jq, jv_number(-1));
      // fallthrough
    case ON_BACKTRACK(EACH):
    case ON_BACKTRACK(EACH_OPT): {
      int idx = jv_number_value(stack_pop(jq));
      jv container = stack_pop(jq);

      int keep_going, is_last = 0;
      jv key, value;
      if (jv_get_kind(container) == JV_KIND_ARRAY) {
        if (opcode == EACH || opcode == EACH_OPT) idx = 0;
        else idx = idx + 1;
        int len = jv_array_length(jv_copy(container));
        keep_going = idx < len;
        is_last = idx == len - 1;
        if (keep_going) {
          key = jv_number(idx);
          value = jv_array_get(jv_copy(container), idx);
        }
      } else if (jv_get_kind(container) == JV_KIND_OBJECT) {
        if (opcode == EACH || opcode == EACH_OPT) idx = jv_object_iter(container);
        else idx = jv_object_iter_next(container, idx);
        keep_going = jv_object_iter_valid(container, idx);
        if (keep_going) {
          key = jv_object_iter_key(container, idx);
          value = jv_object_iter_value(container, idx);
        }
      } else {
        assert(opcode == EACH || opcode == EACH_OPT);
        if (opcode == EACH) {
          print_error(jq,
                      jv_invalid_with_msg(jv_string_fmt("Cannot iterate over %s",
                                                        jv_kind_name(jv_get_kind(container)))));
        }
        keep_going = 0;
      }

      if (!keep_going) {
        jv_free(container);
        goto do_backtrack;
      } else if (is_last) {
        // we don't need to make a backtrack point
        jv_free(container);
        path_append(jq, key);
        stack_push(jq, value);
      } else {
        struct stack_pos spos = stack_get_pos(jq);
        stack_push(jq, container);
        stack_push(jq, jv_number(idx));
        stack_save(jq, pc - 1, spos);
        path_append(jq, key);
        stack_push(jq, value);
      }
      break;
    }

    do_backtrack:
    case BACKTRACK: {
      pc = stack_restore(jq);
      if (!pc) {
        return jv_invalid();
      }
      backtracking = 1;
      break;
    }

    case FORK: {
      stack_save(jq, pc - 1, stack_get_pos(jq));
      pc++; // skip offset this time
      break;
    }

    case ON_BACKTRACK(FORK): {
      uint16_t offset = *pc++;
      pc += offset;
      break;
    }
      
    case CALL_BUILTIN: {
      int nargs = *pc++;
      jv top = stack_pop(jq);
      jv* in = cfunc_input;
      int i;
      in[0] = top;
      for (i = 1; i < nargs; i++) {
        in[i] = stack_pop(jq);
      }
      struct cfunction* function = &frame_current(jq)->bc->globals->cfunctions[*pc++];
      typedef jv (*func_1)(jv);
      typedef jv (*func_2)(jv,jv);
      typedef jv (*func_3)(jv,jv,jv);
      typedef jv (*func_4)(jv,jv,jv,jv);
      typedef jv (*func_5)(jv,jv,jv,jv,jv);
      switch (function->nargs) {
      case 1: top = ((func_1)function->fptr)(in[0]); break;
      case 2: top = ((func_2)function->fptr)(in[0], in[1]); break;
      case 3: top = ((func_3)function->fptr)(in[0], in[1], in[2]); break;
      case 4: top = ((func_4)function->fptr)(in[0], in[1], in[2], in[3]); break;
      case 5: top = ((func_5)function->fptr)(in[0], in[1], in[2], in[3], in[4]); break;
      default: return jv_invalid_with_msg(jv_string("Function takes too many arguments"));
      }
      
      if (jv_is_valid(top)) {
        stack_push(jq, top);
      } else {
        print_error(jq, top);
        goto do_backtrack;
      }
      break;
    }

    case CALL_JQ: {
      jv input = stack_pop(jq);
      uint16_t nclosures = *pc++;
      uint16_t* retaddr = pc + 2 + nclosures*2;
      struct frame* new_frame = frame_push(jq, make_closure(jq, pc),
                                           pc + 2, nclosures);
      new_frame->retdata = jq->stk_top;
      new_frame->retaddr = retaddr;
      pc = new_frame->bc->code;
      stack_push(jq, input);
      break;
    }

    case RET: {
      jv value = stack_pop(jq);
      assert(jq->stk_top == frame_current(jq)->retdata);
      uint16_t* retaddr = frame_current(jq)->retaddr;
      if (retaddr) {
        // function return
        pc = retaddr;
        frame_pop(jq);
      } else {
        // top-level return, yielding value
        struct stack_pos spos = stack_get_pos(jq);
        stack_push(jq, jv_null());
        stack_save(jq, pc - 1, spos);
        return value;
      }
      stack_push(jq, value);
      break;
    }
    case ON_BACKTRACK(RET): {
      // resumed after top-level return
      goto do_backtrack;
    }
    }
  }
}
示例#11
0
文件: execute.c 项目: anandankm/jq
jv jq_next(jq_state *jq) {
  jv cfunc_input[MAX_CFUNCTION_ARGS];

  uint16_t* pc = stack_restore(jq);
  assert(pc);

  int backtracking = !jq->initial_execution;
  jq->initial_execution = 0;
  while (1) {
    uint16_t opcode = *pc;

    if (jq->debug_trace_enabled) {
      dump_operation(frame_current_bytecode(&jq->frame_stk), pc);
      printf("\t");
      const struct opcode_description* opdesc = opcode_describe(opcode);
      data_stk_elem* param = 0;
      int stack_in = opdesc->stack_in;
      if (stack_in == -1) stack_in = pc[1];
      for (int i=0; i<stack_in; i++) {
        if (i == 0) {
          param = forkable_stack_peek(&jq->data_stk);
        } else {
          printf(" | ");
          param = forkable_stack_peek_next(&jq->data_stk, param);
        }
        if (!param) break;
        jv_dump(jv_copy(param->val), 0);
        //printf("<%d>", jv_get_refcnt(param->val));
        //printf(" -- ");
        //jv_dump(jv_copy(jq->path), 0);
      }

      if (backtracking) printf("\t<backtracking>");

      printf("\n");
    }
    if (backtracking) {
      opcode = ON_BACKTRACK(opcode);
      backtracking = 0;
    }
    pc++;

    switch (opcode) {
    default: assert(0 && "invalid instruction");

    case LOADK: {
      jv v = jv_array_get(jv_copy(frame_current_bytecode(&jq->frame_stk)->constants), *pc++);
      assert(jv_is_valid(v));
      jv_free(stack_pop(jq));
      stack_push(jq, v);
      break;
    }

    case DUP: {
      jv v = stack_pop(jq);
      stack_push(jq, jv_copy(v));
      stack_push(jq, v);
      break;
    }

    case DUP2: {
      jv keep = stack_pop(jq);
      jv v = stack_pop(jq);
      stack_push(jq, jv_copy(v));
      stack_push(jq, keep);
      stack_push(jq, v);
      break;
    }

    case SUBEXP_BEGIN: {
      jv v = stack_pop(jq);
      stack_push(jq, jv_copy(v));
      stack_push(jq, v);
      jq->subexp_nest++;
      break;
    }

    case SUBEXP_END: {
      assert(jq->subexp_nest > 0);
      jq->subexp_nest--;
      jv a = stack_pop(jq);
      jv b = stack_pop(jq);
      stack_push(jq, a);
      stack_push(jq, b);
      break;
    }
      
    case POP: {
      jv_free(stack_pop(jq));
      break;
    }

    case APPEND: {
      jv v = stack_pop(jq);
      uint16_t level = *pc++;
      uint16_t vidx = *pc++;
      frame_ptr fp = frame_get_level(&jq->frame_stk, frame_current(&jq->frame_stk), level);
      jv* var = frame_local_var(fp, vidx);
      assert(jv_get_kind(*var) == JV_KIND_ARRAY);
      *var = jv_array_append(*var, v);
      break;
    }

    case INSERT: {
      jv stktop = stack_pop(jq);
      jv v = stack_pop(jq);
      jv k = stack_pop(jq);
      jv objv = stack_pop(jq);
      assert(jv_get_kind(objv) == JV_KIND_OBJECT);
      if (jv_get_kind(k) == JV_KIND_STRING) {
        stack_push(jq, jv_object_set(objv, k, v));
        stack_push(jq, stktop);
      } else {
        print_error(jv_invalid_with_msg(jv_string_fmt("Cannot use %s as object key",
                                                      jv_kind_name(jv_get_kind(k)))));
        jv_free(stktop);
        jv_free(v);
        jv_free(k);
        jv_free(objv);
        goto do_backtrack;
      }
      break;
    }

    case ON_BACKTRACK(RANGE):
    case RANGE: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      frame_ptr fp = frame_get_level(&jq->frame_stk, frame_current(&jq->frame_stk), level);
      jv* var = frame_local_var(fp, v);
      jv max = stack_pop(jq);
      if (jv_get_kind(*var) != JV_KIND_NUMBER ||
          jv_get_kind(max) != JV_KIND_NUMBER) {
        print_error(jv_invalid_with_msg(jv_string_fmt("Range bounds must be numeric")));
        jv_free(max);
        goto do_backtrack;
      } else if (jv_number_value(jv_copy(*var)) >= jv_number_value(jv_copy(max))) {
        /* finished iterating */
        goto do_backtrack;
      } else {
        jv curr = jv_copy(*var);
        *var = jv_number(jv_number_value(*var) + 1);

        stack_save(jq, pc - 3);
        stack_push(jq, jv_copy(max));
        stack_switch(jq);
        stack_push(jq, curr);
      }
      break;
    }

      // FIXME: loadv/storev may do too much copying/freeing
    case LOADV: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      frame_ptr fp = frame_get_level(&jq->frame_stk, frame_current(&jq->frame_stk), level);
      jv* var = frame_local_var(fp, v);
      if (jq->debug_trace_enabled) {
        printf("V%d = ", v);
        jv_dump(jv_copy(*var), 0);
        printf("\n");
      }
      jv_free(stack_pop(jq));
      stack_push(jq, jv_copy(*var));
      break;
    }

    case STOREV: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      frame_ptr fp = frame_get_level(&jq->frame_stk, frame_current(&jq->frame_stk), level);
      jv* var = frame_local_var(fp, v);
      jv val = stack_pop(jq);
      if (jq->debug_trace_enabled) {
        printf("V%d = ", v);
        jv_dump(jv_copy(val), 0);
        printf("\n");
      }
      jv_free(*var);
      *var = val;
      break;
    }

    case PATH_BEGIN: {
      jv v = stack_pop(jq);
      stack_push(jq, jq->path);

      stack_save(jq, pc - 1);
      stack_switch(jq);

      stack_push(jq, jv_number(jq->subexp_nest));
      stack_push(jq, v);

      jq->path = jv_array();
      jq->subexp_nest = 0;
      break;
    }

    case PATH_END: {
      jv v = stack_pop(jq);
      jv_free(v); // discard value, only keep path

      int old_subexp_nest = (int)jv_number_value(stack_pop(jq));

      jv path = jq->path;
      jq->path = stack_pop(jq);

      stack_save(jq, pc - 1);
      stack_push(jq, jv_copy(path));
      stack_switch(jq);

      stack_push(jq, path);
      jq->subexp_nest = old_subexp_nest;
      break;
    }

    case ON_BACKTRACK(PATH_BEGIN):
    case ON_BACKTRACK(PATH_END): {
      jv_free(jq->path);
      jq->path = stack_pop(jq);
      goto do_backtrack;
    }

    case INDEX: {
      jv t = stack_pop(jq);
      jv k = stack_pop(jq);
      path_append(jq, jv_copy(k));
      jv v = jv_get(t, k);
      if (jv_is_valid(v)) {
        stack_push(jq, v);
      } else {
        print_error(v);
        goto do_backtrack;
      }
      break;
    }


    case JUMP: {
      uint16_t offset = *pc++;
      pc += offset;
      break;
    }

    case JUMP_F: {
      uint16_t offset = *pc++;
      jv t = stack_pop(jq);
      jv_kind kind = jv_get_kind(t);
      if (kind == JV_KIND_FALSE || kind == JV_KIND_NULL) {
        pc += offset;
      }
      stack_push(jq, t); // FIXME do this better
      break;
    }

    case EACH: 
      stack_push(jq, jv_number(-1));
      // fallthrough
    case ON_BACKTRACK(EACH): {
      int idx = jv_number_value(stack_pop(jq));
      jv container = stack_pop(jq);

      int keep_going;
      jv key, value;
      if (jv_get_kind(container) == JV_KIND_ARRAY) {
        if (opcode == EACH) idx = 0;
        else idx = idx + 1;
        keep_going = idx < jv_array_length(jv_copy(container));
        if (keep_going) {
          key = jv_number(idx);
          value = jv_array_get(jv_copy(container), idx);
        }
      } else if (jv_get_kind(container) == JV_KIND_OBJECT) {
        if (opcode == EACH) idx = jv_object_iter(container);
        else idx = jv_object_iter_next(container, idx);
        keep_going = jv_object_iter_valid(container, idx);
        if (keep_going) {
          key = jv_object_iter_key(container, idx);
          value = jv_object_iter_value(container, idx);
        }
      } else {
        assert(opcode == EACH);
        print_error(jv_invalid_with_msg(jv_string_fmt("Cannot iterate over %s",
                                                      jv_kind_name(jv_get_kind(container)))));
        keep_going = 0;
      }

      if (!keep_going) {
        jv_free(container);
        goto do_backtrack;
      } else {
        stack_save(jq, pc - 1);
        stack_push(jq, container);
        stack_push(jq, jv_number(idx));
        stack_switch(jq);
        path_append(jq, key);
        stack_push(jq, value);
      }
      break;
    }

    do_backtrack:
    case BACKTRACK: {
      pc = stack_restore(jq);
      if (!pc) {
        return jv_invalid();
      }
      backtracking = 1;
      break;
    }

    case FORK: {
      stack_save(jq, pc - 1);
      stack_switch(jq);
      pc++; // skip offset this time
      break;
    }

    case ON_BACKTRACK(FORK): {
      uint16_t offset = *pc++;
      pc += offset;
      break;
    }
      
    case CALL_BUILTIN: {
      int nargs = *pc++;
      jv top = stack_pop(jq);
      cfunc_input[0] = top;
      for (int i = 1; i < nargs; i++) {
        cfunc_input[i] = stack_pop(jq);
      }
      struct cfunction* func = &frame_current_bytecode(&jq->frame_stk)->globals->cfunctions[*pc++];
      top = cfunction_invoke(func, cfunc_input);
      if (jv_is_valid(top)) {
        stack_push(jq, top);
      } else {
        print_error(top);
        goto do_backtrack;
      }
      break;
    }

    case CALL_JQ: {
      uint16_t nclosures = *pc++;
      uint16_t* retaddr = pc + 2 + nclosures*2;
      frame_ptr new_frame = frame_push(&jq->frame_stk, 
                                       make_closure(&jq->frame_stk, frame_current(&jq->frame_stk), pc),
                                       retaddr);
      pc += 2;
      frame_ptr old_frame = forkable_stack_peek_next(&jq->frame_stk, new_frame);
      assert(nclosures == frame_self(new_frame)->bc->nclosures);
      for (int i=0; i<nclosures; i++) {
        *frame_closure_arg(new_frame, i) = make_closure(&jq->frame_stk, old_frame, pc);
        pc += 2;
      }

      pc = frame_current_bytecode(&jq->frame_stk)->code;
      break;
    }

    case RET: {
      uint16_t* retaddr = *frame_current_retaddr(&jq->frame_stk);
      if (retaddr) {
        // function return
        pc = retaddr;
        frame_pop(&jq->frame_stk);
      } else {
        // top-level return, yielding value
        jv value = stack_pop(jq);
        stack_save(jq, pc - 1);
        stack_push(jq, jv_null());
        stack_switch(jq);
        return value;
      }
      break;
    }
    case ON_BACKTRACK(RET): {
      // resumed after top-level return
      goto do_backtrack;
    }
    }
  }
}