// further move the stack.
	new2 := uintptr(unsafe.Pointer(new))

	t.Logf("old stack pointer %x, new stack pointer %x", old, new2)
	if new2 == old {
		// Check that we didn't screw up the test's escape analysis.
		if cls := runtime.GCTestPointerClass(unsafe.Pointer(new)); cls != "stack" {
			t.Fatalf("test bug: new (%#x) should be a stack pointer, not %s", new2, cls)
		}
		// This was a real failure.
		return false
	}

	// There are unlocked sudogs that point into gp's stack. Stack
	// copying must lock the channels of those sudogs.
	// Set activeStackChans here instead of before we try parking
	// because we could self-deadlock in stack growth on the
	// channel lock.
	gp.activeStackChans = true
	// Mark that it's safe for stack shrinking to occur now,
	// because any thread acquiring this G's stack for shrinking

			buf := make([]byte, 10<<10)
			n := runtime.Stack(buf, true)
			t.Fatalf("timed out after %v waiting for <-ctx.Done(); stacks:\n%s", d, buf[:n])
		}
	}
	// Wait for all the cancel functions to return.
	done := make(chan struct{})
	go func() {
		wg.Wait()
		close(done)
	}()
	select {
	case <-done:
	case <-stuck:
		buf := make([]byte, 10<<10)
		n := runtime.Stack(buf, true)

	EvGoSleep           event.Type = 19 // goroutine calls Sleep [timestamp, stack]
	EvGoBlock           event.Type = 20 // goroutine blocks [timestamp, stack]
	EvGoUnblock         event.Type = 21 // goroutine is unblocked [timestamp, goroutine id, seq, stack]
	EvGoBlockSend       event.Type = 22 // goroutine blocks on chan send [timestamp, stack]
	EvGoBlockRecv       event.Type = 23 // goroutine blocks on chan recv [timestamp, stack]

	stw := stopTheWorld(stwWriteHeapDump)

	// Keep m on this G's stack instead of the system stack.
	// Both readmemstats_m and writeheapdump_m have pretty large
	// peak stack depths and we risk blowing the system stack.
	// This is safe because the world is stopped, so we don't
	// need to worry about anyone shrinking and therefore moving
	// our stack.
	var m MemStats
	systemstack(func() {

			}
		}
	}
	return replaced
}

type ordermarker int

// markTemp returns the top of the temporary variable stack.
func (o *orderState) markTemp() ordermarker {
	return ordermarker(len(o.temp))
}

// popTemp pops temporaries off the stack until reaching the mark,
// which must have been returned by markTemp.
func (o *orderState) popTemp(mark ordermarker) {
	for _, n := range o.temp[mark:] {

// package (assembler).
func ObjRegForAbiReg(r abi.RegIndex, c *Config) int16 {
	m := archRegForAbiReg(r, c)
	return c.registers[m].objNum
}

// ArgWidth returns the amount of stack needed for all the inputs
// and outputs of a function or method, including ABI-defined parameter
// slots and ABI-defined spill slots for register-resident parameters.
//

// finish the message.
//
// dlog can be used from highly-constrained corners of the runtime: it
// is safe to use in the signal handler, from within the write
// barrier, from within the stack implementation, and in places that
// must be recursively nosplit.
//
// This will be compiled away if built without the debuglog build tag.
// However, argument construction may not be. If any of the arguments

	DW_OP_consts              = 0x11 // 1 SLEB128 constant
	DW_OP_dup                 = 0x12 // 0
	DW_OP_drop                = 0x13 // 0
	DW_OP_over                = 0x14 // 0
	DW_OP_pick                = 0x15 // 1 1-byte stack index
	DW_OP_swap                = 0x16 // 0
	DW_OP_rot                 = 0x17 // 0
	DW_OP_xderef              = 0x18 // 0
	DW_OP_abs                 = 0x19 // 0
	DW_OP_and                 = 0x1a // 0

func G0StackOverflow() {
	systemstack(func() {
		g0 := getg()
		sp := getcallersp()
		// The stack bounds for g0 stack is not always precise.
		// Use an artificially small stack, to trigger a stack overflow
		// without actually run out of the system stack (which may seg fault).
		g0.stack.lo = sp - 4096 - stackSystem
		g0.stackguard0 = g0.stack.lo + stackGuard
		g0.stackguard1 = g0.stackguard0

		stackOverflow(nil)
	})
}