Documentation
/*
** Stack frames.
** Copyright (C) 2005-2023 Mike Pall. See Copyright Notice in luajit.h
*/

#ifndef _LJ_FRAME_H
#define _LJ_FRAME_H


#include "lj_obj.h"
#include "lj_bc.h"

/* -- Lua stack frame ----------------------------------------------------- */

/* Frame type markers in LSB of PC (4-byte aligned) or delta (8-byte aligned:
**
**    PC  00  Lua frame
** delta 001  C frame
** delta 010  Continuation frame
** delta 011  Lua vararg frame
** delta 101  cpcall() frame
** delta 110  ff pcall() frame
** delta 111  ff pcall() frame with active hook
*/
enum {
  FRAME_LUA, FRAME_C, FRAME_CONT, FRAME_VARG,
  FRAME_LUAP, FRAME_CP, FRAME_PCALL, FRAME_PCALLH
};
#define FRAME_TYPE		3

#define FRAME_P			4

#define FRAME_TYPEP		(FRAME_TYPE|FRAME_P)


/* Macros to access and modify Lua frames. */
#if LJ_FR2
/* Two-slot frame info, required for 64 bit PC/GCRef:
**
**                   base-2  base-1      |  base  base+1 ...
**                  [func   PC/delta/ft] | [slots ...]
**                  ^-- frame            | ^-- base   ^-- top
**
** Continuation frames:
**
**   base-4  base-3  base-2  base-1      |  base  base+1 ...
**  [cont      PC ] [func   PC/delta/ft] | [slots ...]
**                  ^-- frame            | ^-- base   ^-- top
*/
#define frame_gc(f)		(gcval((f)-1))

#define frame_ftsz(f)		((ptrdiff_t)(f)->ftsz)

#define frame_pc(f)		((const BCIns *)frame_ftsz(f))

#define setframe_gc(f, p, tp)	(setgcVraw((f), (p), (tp)))

#define setframe_ftsz(f, sz)	((f)->ftsz = (sz))

#define setframe_pc(f, pc)	((f)->ftsz = (int64_t)(intptr_t)(pc))

#else
/* One-slot frame info, sufficient for 32 bit PC/GCRef:
**
**              base-1              |  base  base+1 ...
**              lo     hi           |
**             [func | PC/delta/ft] | [slots ...]
**             ^-- frame            | ^-- base   ^-- top
**
** Continuation frames:
**
**  base-2      base-1              |  base  base+1 ...
**  lo     hi   lo     hi           |
** [cont | PC] [func | PC/delta/ft] | [slots ...]
**             ^-- frame            | ^-- base   ^-- top
*/
#define frame_gc(f)		(gcref((f)->fr.func))

#define frame_ftsz(f)		((ptrdiff_t)(f)->fr.tp.ftsz)

#define frame_pc(f)		(mref((f)->fr.tp.pcr, const BCIns))

#define setframe_gc(f, p, tp)	(setgcref((f)->fr.func, (p)), UNUSED(tp))

#define setframe_ftsz(f, sz)	((f)->fr.tp.ftsz = (int32_t)(sz))

#define setframe_pc(f, pc)	(setmref((f)->fr.tp.pcr, (pc)))

#endif

#define frame_type(f)		(frame_ftsz(f) & FRAME_TYPE)

#define frame_typep(f)		(frame_ftsz(f) & FRAME_TYPEP)

#define frame_islua(f)		(frame_type(f) == FRAME_LUA)

#define frame_isc(f)		(frame_type(f) == FRAME_C)

#define frame_iscont(f)		(frame_typep(f) == FRAME_CONT)

#define frame_isvarg(f)		(frame_typep(f) == FRAME_VARG)

#define frame_ispcall(f)	((frame_ftsz(f) & 6) == FRAME_PCALL)


#define frame_func(f)		(&frame_gc(f)->fn)

#define frame_delta(f)		(frame_ftsz(f) >> 3)

#define frame_sized(f)		(frame_ftsz(f) & ~FRAME_TYPEP)


enum { LJ_CONT_TAILCALL, LJ_CONT_FFI_CALLBACK };  /* Special continuations. */

#if LJ_FR2
#define frame_contpc(f)		(frame_pc((f)-2))

#define frame_contv(f)		(((f)-3)->u64)

#else
#define frame_contpc(f)		(frame_pc((f)-1))

#define frame_contv(f)		(((f)-1)->u32.lo)

#endif
#if LJ_FR2
#define frame_contf(f)		((ASMFunction)(uintptr_t)((f)-3)->u64)

#elif LJ_64
#define frame_contf(f) \

  ((ASMFunction)(void *)((intptr_t)lj_vm_asm_begin + \
			 (intptr_t)(int32_t)((f)-1)->u32.lo))
#else
#define frame_contf(f)		((ASMFunction)gcrefp(((f)-1)->gcr, void))

#endif
#define frame_iscont_fficb(f) \

  (LJ_HASFFI && frame_contv(f) == LJ_CONT_FFI_CALLBACK)

#define frame_prevl(f)		((f) - (1+LJ_FR2+bc_a(frame_pc(f)[-1])))

#define frame_prevd(f)		((TValue *)((char *)(f) - frame_sized(f)))

#define frame_prev(f)		(frame_islua(f)?frame_prevl(f):frame_prevd(f))

/* Note: this macro does not skip over FRAME_VARG. */

/* -- C stack frame ------------------------------------------------------- */

/* Macros to access and modify the C stack frame chain. */

/* These definitions must match with the arch-specific *.dasc files. */
#if LJ_TARGET_X86
#if LJ_ABI_WIN
#define CFRAME_OFS_ERRF		(19*4)

#define CFRAME_OFS_NRES		(18*4)

#define CFRAME_OFS_PREV		(17*4)

#define CFRAME_OFS_L		(16*4)

#define CFRAME_OFS_SEH		(9*4)

#define CFRAME_OFS_PC		(6*4)

#define CFRAME_OFS_MULTRES	(5*4)

#define CFRAME_SIZE		(16*4)

#define CFRAME_SHIFT_MULTRES	0

#else
#define CFRAME_OFS_ERRF		(15*4)

#define CFRAME_OFS_NRES		(14*4)

#define CFRAME_OFS_PREV		(13*4)

#define CFRAME_OFS_L		(12*4)

#define CFRAME_OFS_PC		(6*4)

#define CFRAME_OFS_MULTRES	(5*4)

#define CFRAME_SIZE		(12*4)

#define CFRAME_SHIFT_MULTRES	0

#endif
#elif LJ_TARGET_X64
#if LJ_ABI_WIN
#define CFRAME_OFS_PREV		(13*8)

#if LJ_GC64
#define CFRAME_OFS_PC		(12*8)

#define CFRAME_OFS_L		(11*8)

#define CFRAME_OFS_ERRF		(21*4)

#define CFRAME_OFS_NRES		(20*4)

#define CFRAME_OFS_MULTRES	(8*4)

#else
#define CFRAME_OFS_PC		(25*4)

#define CFRAME_OFS_L		(24*4)

#define CFRAME_OFS_ERRF		(23*4)

#define CFRAME_OFS_NRES		(22*4)

#define CFRAME_OFS_MULTRES	(21*4)

#endif
#define CFRAME_SIZE		(10*8)

#define CFRAME_SIZE_JIT		(CFRAME_SIZE + 9*16 + 4*8)

#define CFRAME_SHIFT_MULTRES	0

#else
#define CFRAME_OFS_PREV		(4*8)

#if LJ_GC64
#define CFRAME_OFS_PC		(3*8)

#define CFRAME_OFS_L		(2*8)

#define CFRAME_OFS_ERRF		(3*4)

#define CFRAME_OFS_NRES		(2*4)

#define CFRAME_OFS_MULTRES	(0*4)

#else
#define CFRAME_OFS_PC		(7*4)

#define CFRAME_OFS_L		(6*4)

#define CFRAME_OFS_ERRF		(5*4)

#define CFRAME_OFS_NRES		(4*4)

#define CFRAME_OFS_MULTRES	(1*4)

#endif
#if LJ_NO_UNWIND
#define CFRAME_SIZE		(12*8)

#else
#define CFRAME_SIZE		(10*8)

#endif
#define CFRAME_SIZE_JIT		(CFRAME_SIZE + 16)

#define CFRAME_SHIFT_MULTRES	0

#endif
#elif LJ_TARGET_ARM
#define CFRAME_OFS_ERRF		24

#define CFRAME_OFS_NRES		20

#define CFRAME_OFS_PREV		16

#define CFRAME_OFS_L		12

#define CFRAME_OFS_PC		8

#define CFRAME_OFS_MULTRES	4

#if LJ_ARCH_HASFPU
#define CFRAME_SIZE		128

#else
#define CFRAME_SIZE		64

#endif
#define CFRAME_SHIFT_MULTRES	3

#elif LJ_TARGET_ARM64
#define CFRAME_OFS_ERRF		36

#define CFRAME_OFS_NRES		40

#define CFRAME_OFS_PREV		0

#define CFRAME_OFS_L		16

#define CFRAME_OFS_PC		8

#define CFRAME_OFS_MULTRES	32

#define CFRAME_SIZE		208

#define CFRAME_SHIFT_MULTRES	3

#elif LJ_TARGET_PPC
#if LJ_TARGET_XBOX360
#define CFRAME_OFS_ERRF		424

#define CFRAME_OFS_NRES		420

#define CFRAME_OFS_PREV		400

#define CFRAME_OFS_L		416

#define CFRAME_OFS_PC		412

#define CFRAME_OFS_MULTRES	408

#define CFRAME_SIZE		384

#define CFRAME_SHIFT_MULTRES	3

#elif LJ_ARCH_PPC32ON64
#define CFRAME_OFS_ERRF		472

#define CFRAME_OFS_NRES		468

#define CFRAME_OFS_PREV		448

#define CFRAME_OFS_L		464

#define CFRAME_OFS_PC		460

#define CFRAME_OFS_MULTRES	456

#define CFRAME_SIZE		400

#define CFRAME_SHIFT_MULTRES	3

#else
#define CFRAME_OFS_ERRF		48

#define CFRAME_OFS_NRES		44

#define CFRAME_OFS_PREV		40

#define CFRAME_OFS_L		36

#define CFRAME_OFS_PC		32

#define CFRAME_OFS_MULTRES	28

#define CFRAME_SIZE		(LJ_ARCH_HASFPU ? 272 : 128)

#define CFRAME_SHIFT_MULTRES	3

#endif
#elif LJ_TARGET_MIPS32
#if LJ_ARCH_HASFPU
#define CFRAME_OFS_ERRF		124

#define CFRAME_OFS_NRES		120

#define CFRAME_OFS_PREV		116

#define CFRAME_OFS_L		112

#define CFRAME_SIZE		112

#else
#define CFRAME_OFS_ERRF		76

#define CFRAME_OFS_NRES		72

#define CFRAME_OFS_PREV		68

#define CFRAME_OFS_L		64

#define CFRAME_SIZE		64

#endif
#define CFRAME_OFS_PC		20

#define CFRAME_OFS_MULTRES	16

#define CFRAME_SHIFT_MULTRES	3

#elif LJ_TARGET_MIPS64
#if LJ_ARCH_HASFPU
#define CFRAME_OFS_ERRF		188

#define CFRAME_OFS_NRES		184

#define CFRAME_OFS_PREV		176

#define CFRAME_OFS_L		168

#define CFRAME_OFS_PC		160

#define CFRAME_SIZE		192

#else
#define CFRAME_OFS_ERRF		124

#define CFRAME_OFS_NRES		120

#define CFRAME_OFS_PREV		112

#define CFRAME_OFS_L		104

#define CFRAME_OFS_PC		96

#define CFRAME_SIZE		128

#endif
#define CFRAME_OFS_MULTRES	0

#define CFRAME_SHIFT_MULTRES	3

#else
#error "Missing CFRAME_* definitions for this architecture"
#endif

#ifndef CFRAME_SIZE_JIT
#define CFRAME_SIZE_JIT		CFRAME_SIZE

#endif

#define CFRAME_RESUME		1

#define CFRAME_UNWIND_FF	2  /* Only used in unwinder. */

#define CFRAME_RAWMASK		(~(intptr_t)(CFRAME_RESUME|CFRAME_UNWIND_FF))


#define cframe_errfunc(cf)	(*(int32_t *)(((char *)(cf))+CFRAME_OFS_ERRF))

#define cframe_nres(cf)		(*(int32_t *)(((char *)(cf))+CFRAME_OFS_NRES))

#define cframe_prev(cf)		(*(void **)(((char *)(cf))+CFRAME_OFS_PREV))

#define cframe_multres(cf)  (*(uint32_t *)(((char *)(cf))+CFRAME_OFS_MULTRES))

#define cframe_multres_n(cf)	(cframe_multres((cf)) >> CFRAME_SHIFT_MULTRES)

#define cframe_L(cf) \

  (&gcref(*(GCRef *)(((char *)(cf))+CFRAME_OFS_L))->th)
#define cframe_pc(cf) \

  (mref(*(MRef *)(((char *)(cf))+CFRAME_OFS_PC), const BCIns))
#define setcframe_L(cf, L) \

  (setmref(*(MRef *)(((char *)(cf))+CFRAME_OFS_L), (L)))
#define setcframe_pc(cf, pc) \

  (setmref(*(MRef *)(((char *)(cf))+CFRAME_OFS_PC), (pc)))
#define cframe_canyield(cf)	((intptr_t)(cf) & CFRAME_RESUME)

#define cframe_unwind_ff(cf)	((intptr_t)(cf) & CFRAME_UNWIND_FF)

#define cframe_raw(cf)		((void *)((intptr_t)(cf) & CFRAME_RAWMASK))

#define cframe_Lpc(L)		cframe_pc(cframe_raw(L->cframe))


#endif