"unsafe"
)

// A stkframe holds information about a single physical stack frame.
type stkframe struct {
	// fn is the function being run in this frame. If there is
	// inlining, this is the outermost function.
	fn funcInfo

	// pc is the program counter within fn.
	//
	// The meaning of this is subtle:
	//
	// - Typically, this frame performed a regular function call
	//   and this is the return PC (just after the CALL

				n++
			}
			return n < len(dst)
		}
	)

outer:
	for _, retPC := range pcBuf[1:] {
		callPC := retPC - 1
		fi := findfunc(callPC)
		if !fi.valid() {
			// There is no funcInfo if callPC belongs to a C function. In this case
			// we still keep the pc, but don't attempt to expand inlined frames.
			if more := skipOrAdd(retPC); !more {
				break outer
			}
			continue
		}

	// Ignore calls to external functions. Assume that these calls
	// are only ever happening on the system stack, where there's
	// plenty of room.
	if ldr.AttrExternal(sym) {
		return 0, nil
	}
	if info := ldr.FuncInfo(sym); !info.Valid() { // also external
		return 0, nil
	}

	// Track the maximum height of this function and, if we're
	// recording the graph, its out-edges.
	var edges []stackCheckEdge
	maxHeight := 0

	return (b >> (i % 8)) & 1
}

// bv describes the memory starting at address scanp.
// Adjust any pointers contained therein.
func adjustpointers(scanp unsafe.Pointer, bv *bitvector, adjinfo *adjustinfo, f funcInfo) {
	minp := adjinfo.old.lo
	maxp := adjinfo.old.hi
	delta := adjinfo.delta
	num := uintptr(bv.n)
	// If this frame might contain channel receive slots, use CAS

		// Go frames).
		if skip == 0 {
			n += copy(pcBuf[n:], cgoBuf[:cgoN])
		}
	}
	return n
}

// printArgs prints function arguments in traceback.
func printArgs(f funcInfo, argp unsafe.Pointer, pc uintptr) {
	p := (*[abi.TraceArgsMaxLen]uint8)(funcdata(f, abi.FUNCDATA_ArgInfo))
	if p == nil {
		return
	}

	liveInfo := funcdata(f, abi.FUNCDATA_ArgLiveInfo)

// 0-based.)

// Auxiliary symbols.
//
// Each symbol may (or may not) be associated with a number of auxiliary
// symbols. They are described in the Aux block. See Aux struct below.
// Currently a symbol's Gotype, FuncInfo, and associated DWARF symbols
// are auxiliary symbols.

const stringRefSize = 8 // two uint32s

type FingerprintType [8]byte

func (fp FingerprintType) IsZero() bool { return fp == FingerprintType{} }

func (d *dwctxt) calcCompUnitRanges() {
	var prevUnit *sym.CompilationUnit
	for _, s := range d.linkctxt.Textp {
		sym := loader.Sym(s)

		fi := d.ldr.FuncInfo(sym)
		if !fi.Valid() {
			continue
		}

		// Skip linker-created functions (ex: runtime.addmoduledata), since they
		// don't have DWARF to begin with.
		unit := d.ldr.SymUnit(sym)

			u.next()
		}

		p.lr = u.frame.lr
		p.sp = unsafe.Pointer(u.frame.sp)
		p.fp = unsafe.Pointer(u.frame.fp)

		ok = true
	})

	return
}

func (p *_panic) initOpenCodedDefers(fn funcInfo, varp unsafe.Pointer) bool {
	fd := funcdata(fn, abi.FUNCDATA_OpenCodedDeferInfo)
	if fd == nil {
		return false
	}

	if fn.deferreturn == 0 {
		throw("missing deferreturn")
	}

			// Pass the spill/unspill information along to the assembler, offset by size of
			// the saved LR slot.
			addr := ssagen.SpillSlotAddr(a, ppc64.REGSP, base.Ctxt.Arch.FixedFrameSize)
			s.FuncInfo().AddSpill(
				obj.RegSpill{Reg: a.Reg, Addr: addr, Unspill: loadByType(a.Type), Spill: storeByType(a.Type)})
		}
		v.Block.Func.RegArgs = nil

		ssagen.CheckArgReg(v)

	case ssa.OpPPC64DIVD:

	lineRunStart *obj.Prog

	// wasm: The number of values on the WebAssembly stack. This is only used as a safeguard.
	OnWasmStackSkipped int
}

func (s *State) FuncInfo() *obj.FuncInfo {
	return s.pp.CurFunc.LSym.Func()
}

// Prog appends a new Prog.
func (s *State) Prog(as obj.As) *obj.Prog {
	p := s.pp.Prog(as)
	if objw.LosesStmtMark(as) {
		return p
	}