piecrust: preservation of caller's economic mode

piecrust/src/imports.rs

@@ -258,6 +258,11 @@ pub(crate) fn c(
  // copy back result
  callee.read_argument(&mut memory[argbuf_ofs..][..ret_len as usize]);
  callee.read_eco_mode_buf(&mut memory[eco_mode_ofs..][..ECO_MODE_LEN]);
+ // if depth of the stack is 3 or more, economic mode is not read
+ const ECO_STACK_DEPTH: usize = 2;
+ if env.nth_from_top(ECO_STACK_DEPTH).is_some() {
+ callee.clear_eco_mode();
+ }
 
  let callee_remaining = callee.get_remaining_gas();
  let callee_spent = callee_limit - callee_remaining;