// Copyright 2014 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.

//go:build darwin || freebsd || linux || netbsd || openbsd

package runtime

import (
	"internal/abi"
	"internal/goarch"
	"runtime/internal/sys"
	"unsafe"
)

func dumpregs(c *sigctxt) {
	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("r11     ", hex(c.r11()), "\n")
	print("r12     ", hex(c.r12()), "\n")
	print("r13     ", hex(c.r13()), "\n")
	print("r14     ", hex(c.r14()), "\n")
	print("r15     ", hex(c.r15()), "\n")
	print("r16     ", hex(c.r16()), "\n")
	print("r17     ", hex(c.r17()), "\n")
	print("r18     ", hex(c.r18()), "\n")
	print("r19     ", hex(c.r19()), "\n")
	print("r20     ", hex(c.r20()), "\n")
	print("r21     ", hex(c.r21()), "\n")
	print("r22     ", hex(c.r22()), "\n")
	print("r23     ", hex(c.r23()), "\n")
	print("r24     ", hex(c.r24()), "\n")
	print("r25     ", hex(c.r25()), "\n")
	print("r26     ", hex(c.r26()), "\n")
	print("r27     ", hex(c.r27()), "\n")
	print("r28     ", hex(c.r28()), "\n")
	print("r29     ", hex(c.r29()), "\n")
	print("lr      ", hex(c.lr()), "\n")
	print("sp      ", hex(c.sp()), "\n")
	print("pc      ", hex(c.pc()), "\n")
	print("fault   ", hex(c.fault()), "\n")
}

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

func (c *sigctxt) setsigpc(x uint64) { c.set_pc(x) }
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() - sys.StackAlign // needs only sizeof uint64, but must align the stack
	c.set_sp(sp)
	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.lr()
	// Make sure a valid frame pointer is saved on the stack so that the
	// frame pointer checks in adjustframe are happy, if they're enabled.
	// Frame pointer unwinding won't visit the sigpanic frame, since
	// sigpanic will save the same frame pointer before calling into a panic
	// function.
	*(*uint64)(unsafe.Pointer(uintptr(sp - goarch.PtrSize))) = c.r29()

	pc := gp.sigpc

	if shouldPushSigpanic(gp, pc, uintptr(c.lr())) {
		// Make it look the like faulting PC called sigpanic.
		c.set_lr(uint64(pc))
	}

	// In case we are panicking from external C code
	c.set_r28(uint64(uintptr(unsafe.Pointer(gp))))
	c.set_pc(uint64(abi.FuncPCABIInternal(sigpanic)))
}

func (c *sigctxt) pushCall(targetPC, resumePC 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 space is known to gentraceback.
	sp := c.sp() - 16 // SP needs 16-byte alignment
	c.set_sp(sp)
	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.lr()
	// Make sure a valid frame pointer is saved on the stack so that the
	// frame pointer checks in adjustframe are happy, if they're enabled.
	// This is not actually used for unwinding.
	*(*uint64)(unsafe.Pointer(uintptr(sp - goarch.PtrSize))) = c.r29()
	// Set up PC and LR to pretend the function being signaled
	// calls targetPC at resumePC.
	c.set_lr(uint64(resumePC))
	c.set_pc(uint64(targetPC))
}