// should never return
	CALL	runtime·abort(SB)
	UNDEF

/*
 * support for morestack
 */

// Called during function prolog when more stack is needed.
// Caller has already loaded:
// R1: framesize, R2: argsize, R3: LR
//
// The traceback routines see morestack on a g0 as being
// the top of a stack (for example, morestack calling newstack
// calling the scheduler calling newm calling gc), so we must

	//   execution will continue, but it may not be the
	//   instruction following a CALL. This may be from
	//   cooperative preemption, in which case this is the
	//   instruction after the call to morestack. Or this may be
	//   from a signal or an un-started goroutine, in which case
	//   PC could be any instruction, including the first
	//   instruction in a function. Conventionally, we use pc-1

	// Move the stack repeatedly to make sure we're not doubling
	// it each time.
	for i := 0; i < 100; i++ {
		runtime.GCTestMoveStackOnNextCall()
		moveStack1(false)
	}
}

//go:noinline
func moveStack1(x bool) {
	// Make sure this function doesn't get auto-nosplit.
	if x {
		println("x")
	}
}

func TestGCTestIsReachable(t *testing.T) {
	var all, half []unsafe.Pointer

	// should never return
	CALL	runtime·abort(SB)
	UNDEF

/*
 * support for morestack
 */

// Called during function prolog when more stack is needed.
// R3 prolog's LR
// using NOFRAME means do not save LR on stack.
//
// The traceback routines see morestack on a g0 as being
// the top of a stack (for example, morestack calling newstack
// calling the scheduler calling newm calling gc), so we must

	MOVL	0(AX), AX
	CALL	AX

	// should never return
	CALL	runtime·abort(SB)
	UNDEF

/*
 * support for morestack
 */

// Called during function prolog when more stack is needed.
//
// The traceback routines see morestack on a g0 as being
// the top of a stack (for example, morestack calling newstack
// calling the scheduler calling newm calling gc), so we must

	// Check if we are running on g0 stack, and if we are,
	// call fn directly instead of creating the closure.
	// for the systemstack argument.
	//
	// A closure can't be marked as nosplit, so it might
	// call morestack if we are at the g0 stack limit.
	// If that happens, the runtime will call abort
	// and end up in sigtrampgo again.
	// TODO: revisit this workaround if/when closures
	// can be compiled as nosplit.
	//

start 136 nosplit call f; f 0 nosplit; REJECT

# Calling a splitting function from a nosplit function requires
# having room for the saved caller PC of the call but also the
# saved caller PC for the call to morestack.
# Architectures differ in the same way as before.
start 96 nosplit call f; f 0 call f
start 100 nosplit call f; f 0 call f; REJECT ppc64 ppc64le
start 104 nosplit call f; f 0 call f; REJECT ppc64 ppc64le amd64 arm64

		// here we'll see a seemingly self-recursive call, which is in
		// fact not.
		// This is normally ok, as we use the return address saved on
		// stack for unwinding, not the LR value. But if this is a
		// call to morestack, we haven't created the frame, and we'll
		// use the LR for unwinding, which will be bad.
		return false, 0
	}
	up, startpc := pcdatavalue2(f, abi.PCDATA_UnsafePoint, pc)
	if up == abi.UnsafePointUnsafe {

for execution.

nosplit functions
-----------------

Most functions start with a prologue that inspects the stack pointer
and the current G's stack bound and calls `morestack` if the stack
needs to grow.

Functions can be marked `//go:nosplit` (or `NOSPLIT` in assembly) to
indicate that they should not get this prologue. This has several
uses:

	MOVQ	0(AX), AX
	CALL	AX

	// should never return
	CALL	runtime·abort(SB)
	UNDEF

/*
 * support for morestack
 */

// Called during function prolog when more stack is needed.
//
// The traceback routines see morestack on a g0 as being
// the top of a stack (for example, morestack calling newstack
// calling the scheduler calling newm calling gc), so we must