// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build darwin dragonfly freebsd linux netbsd openbsd

package runtime

import "unsafe"

func dumpregs(c *sigctxt) {
	print("trap    ", hex(c.trap()), "\n")
	print("error   ", hex(c.error()), "\n")
	print("oldmask ", hex(c.oldmask()), "\n")
	print("r0      ", hex(c.r0()), "\n")
	print("r1      ", hex(c.r1()), "\n")
	print("r2      ", hex(c.r2()), "\n")
	print("r3      ", hex(c.r3()), "\n")
	print("r4      ", hex(c.r4()), "\n")
	print("r5      ", hex(c.r5()), "\n")
	print("r6      ", hex(c.r6()), "\n")
	print("r7      ", hex(c.r7()), "\n")
	print("r8      ", hex(c.r8()), "\n")
	print("r9      ", hex(c.r9()), "\n")
	print("r10     ", hex(c.r10()), "\n")
	print("fp      ", hex(c.fp()), "\n")
	print("ip      ", hex(c.ip()), "\n")
	print("sp      ", hex(c.sp()), "\n")
	print("lr      ", hex(c.lr()), "\n")
	print("pc      ", hex(c.pc()), "\n")
	print("cpsr    ", hex(c.cpsr()), "\n")
	print("fault   ", hex(c.fault()), "\n")
}

//go:nosplit
//go:nowritebarrierrec
func (c *sigctxt) sigpc() uintptr { return uintptr(c.pc()) }

func (c *sigctxt) sigsp() uintptr { return uintptr(c.sp()) }
func (c *sigctxt) siglr() uintptr { return uintptr(c.lr()) }

// preparePanic sets up the stack to look like a call to sigpanic.
func (c *sigctxt) preparePanic(sig uint32, gp *g) {
	// We arrange lr, and pc to pretend the panicking
	// function calls sigpanic directly.
	// Always save LR to stack so that panics in leaf
	// functions are correctly handled. This smashes
	// the stack frame but we're not going back there
	// anyway.
	sp := c.sp() - 4
	c.set_sp(sp)
	*(*uint32)(unsafe.Pointer(uintptr(sp))) = c.lr()

	pc := gp.sigpc

	if shouldPushSigpanic(gp, pc, uintptr(c.lr())) {
		// Make it look the like faulting PC called sigpanic.
		c.set_lr(uint32(pc))
	}

	// In case we are panicking from external C code
	c.set_r10(uint32(uintptr(unsafe.Pointer(gp))))
	c.set_pc(uint32(funcPC(sigpanic)))
}

// TODO(issue 35439): enabling async preemption causes failures on darwin/arm.
// Disable for now.
const pushCallSupported = GOOS != "darwin"

func (c *sigctxt) pushCall(targetPC uintptr) {
	// Push the LR to stack, as we'll clobber it in order to
	// push the call. The function being pushed is responsible
	// for restoring the LR and setting the SP back.
	// This extra slot is known to gentraceback.
	sp := c.sp() - 4
	c.set_sp(sp)
	*(*uint32)(unsafe.Pointer(uintptr(sp))) = c.lr()
	// Set up PC and LR to pretend the function being signaled
	// calls targetPC at the faulting PC.
	c.set_lr(c.pc())
	c.set_pc(uint32(targetPC))
}