/*
** SSA IR (Intermediate Representation) format.
** Copyright (C) 2005-2015 Mike Pall. See Copyright Notice in luajit.h
*/

#ifndef _LJ_IR_H
#define _LJ_IR_H

#include "lj_obj.h"

/* -- IR instructions ----------------------------------------------------- */

/* IR instruction definition. Order matters, see below. ORDER IR */
#define IRDEF(_) \
  /* Guarded assertions. */ \
  /* Must be properly aligned to flip opposites (^1) and (un)ordered (^4). */ \
  _(LT,		N , ref, ref) \
  _(GE,		N , ref, ref) \
  _(LE,		N , ref, ref) \
  _(GT,		N , ref, ref) \
  \
  _(ULT,	N , ref, ref) \
  _(UGE,	N , ref, ref) \
  _(ULE,	N , ref, ref) \
  _(UGT,	N , ref, ref) \
  \
  _(EQ,		C , ref, ref) \
  _(NE,		C , ref, ref) \
  \
  _(ABC,	N , ref, ref) \
  _(RETF,	S , ref, ref) \
  \
  /* Miscellaneous ops. */ \
  _(NOP,	N , ___, ___) \
  _(BASE,	N , lit, lit) \
  _(PVAL,	N , lit, ___) \
  _(GCSTEP,	S , ___, ___) \
  _(HIOP,	S , ref, ref) \
  _(LOOP,	S , ___, ___) \
  _(USE,	S , ref, ___) \
  _(PHI,	S , ref, ref) \
  _(RENAME,	S , ref, lit) \
  _(PROF,	S , ___, ___) \
  \
  /* Constants. */ \
  _(KPRI,	N , ___, ___) \
  _(KINT,	N , cst, ___) \
  _(KGC,	N , cst, ___) \
  _(KPTR,	N , cst, ___) \
  _(KKPTR,	N , cst, ___) \
  _(KNULL,	N , cst, ___) \
  _(KNUM,	N , cst, ___) \
  _(KINT64,	N , cst, ___) \
  _(KSLOT,	N , ref, lit) \
  \
  /* Bit ops. */ \
  _(BNOT,	N , ref, ___) \
  _(BSWAP,	N , ref, ___) \
  _(BAND,	C , ref, ref) \
  _(BOR,	C , ref, ref) \
  _(BXOR,	C , ref, ref) \
  _(BSHL,	N , ref, ref) \
  _(BSHR,	N , ref, ref) \
  _(BSAR,	N , ref, ref) \
  _(BROL,	N , ref, ref) \
  _(BROR,	N , ref, ref) \
  \
  /* Arithmetic ops. ORDER ARITH */ \
  _(ADD,	C , ref, ref) \
  _(SUB,	N , ref, ref) \
  _(MUL,	C , ref, ref) \
  _(DIV,	N , ref, ref) \
  _(MOD,	N , ref, ref) \
  _(POW,	N , ref, ref) \
  _(NEG,	N , ref, ref) \
  \
  _(ABS,	N , ref, ref) \
  _(ATAN2,	N , ref, ref) \
  _(LDEXP,	N , ref, ref) \
  _(MIN,	C , ref, ref) \
  _(MAX,	C , ref, ref) \
  _(FPMATH,	N , ref, lit) \
  \
  /* Overflow-checking arithmetic ops. */ \
  _(ADDOV,	CW, ref, ref) \
  _(SUBOV,	NW, ref, ref) \
  _(MULOV,	CW, ref, ref) \
  \
  /* Memory ops. A = array, H = hash, U = upvalue, F = field, S = stack. */ \
  \
  /* Memory references. */ \
  _(AREF,	R , ref, ref) \
  _(HREFK,	R , ref, ref) \
  _(HREF,	L , ref, ref) \
  _(NEWREF,	S , ref, ref) \
  _(UREFO,	LW, ref, lit) \
  _(UREFC,	LW, ref, lit) \
  _(FREF,	R , ref, lit) \
  _(STRREF,	N , ref, ref) \
  _(LREF,	L , ___, ___) \
  \
  /* Loads and Stores. These must be in the same order. */ \
  _(ALOAD,	L , ref, ___) \
  _(HLOAD,	L , ref, ___) \
  _(ULOAD,	L , ref, ___) \
  _(FLOAD,	L , ref, lit) \
  _(XLOAD,	L , ref, lit) \
  _(SLOAD,	L , lit, lit) \
  _(VLOAD,	L , ref, ___) \
  \
  _(ASTORE,	S , ref, ref) \
  _(HSTORE,	S , ref, ref) \
  _(USTORE,	S , ref, ref) \
  _(FSTORE,	S , ref, ref) \
  _(XSTORE,	S , ref, ref) \
  \
  /* Allocations. */ \
  _(SNEW,	N , ref, ref)  /* CSE is ok, not marked as A. */ \
  _(XSNEW,	A , ref, ref) \
  _(TNEW,	AW, lit, lit) \
  _(TDUP,	AW, ref, ___) \
  _(CNEW,	AW, ref, ref) \
  _(CNEWI,	NW, ref, ref)  /* CSE is ok, not marked as A. */ \
  \
  /* Buffer operations. */ \
  _(BUFHDR,	L , ref, lit) \
  _(BUFPUT,	L , ref, ref) \
  _(BUFSTR,	A , ref, ref) \
  \
  /* Barriers. */ \
  _(TBAR,	S , ref, ___) \
  _(OBAR,	S , ref, ref) \
  _(XBAR,	S , ___, ___) \
  \
  /* Type conversions. */ \
  _(CONV,	NW, ref, lit) \
  _(TOBIT,	N , ref, ref) \
  _(TOSTR,	N , ref, lit) \
  _(STRTO,	N , ref, ___) \
  \
  /* Calls. */ \
  _(CALLN,	N , ref, lit) \
  _(CALLA,	A , ref, lit) \
  _(CALLL,	L , ref, lit) \
  _(CALLS,	S , ref, lit) \
  _(CALLXS,	S , ref, ref) \
  _(CARG,	N , ref, ref) \
  \
  /* End of list. */

/* IR opcodes (max. 256). */
typedef enum {
#define IRENUM(name, m, m1, m2)	IR_##name,
IRDEF(IRENUM)
#undef IRENUM
  IR__MAX
} IROp;

/* Stored opcode. */
typedef uint8_t IROp1;

LJ_STATIC_ASSERT(((int)IR_EQ^1) == (int)IR_NE);
LJ_STATIC_ASSERT(((int)IR_LT^1) == (int)IR_GE);
LJ_STATIC_ASSERT(((int)IR_LE^1) == (int)IR_GT);
LJ_STATIC_ASSERT(((int)IR_LT^3) == (int)IR_GT);
LJ_STATIC_ASSERT(((int)IR_LT^4) == (int)IR_ULT);

/* Delta between xLOAD and xSTORE. */
#define IRDELTA_L2S		((int)IR_ASTORE - (int)IR_ALOAD)

LJ_STATIC_ASSERT((int)IR_HLOAD + IRDELTA_L2S == (int)IR_HSTORE);
LJ_STATIC_ASSERT((int)IR_ULOAD + IRDELTA_L2S == (int)IR_USTORE);
LJ_STATIC_ASSERT((int)IR_FLOAD + IRDELTA_L2S == (int)IR_FSTORE);
LJ_STATIC_ASSERT((int)IR_XLOAD + IRDELTA_L2S == (int)IR_XSTORE);

/* -- Named IR literals --------------------------------------------------- */

/* FPMATH sub-functions. ORDER FPM. */
#define IRFPMDEF(_) \
  _(FLOOR) _(CEIL) _(TRUNC)  /* Must be first and in this order. */ \
  _(SQRT) _(EXP) _(EXP2) _(LOG) _(LOG2) _(LOG10) \
  _(SIN) _(COS) _(TAN) \
  _(OTHER)

typedef enum {
#define FPMENUM(name)		IRFPM_##name,
IRFPMDEF(FPMENUM)
#undef FPMENUM
  IRFPM__MAX
} IRFPMathOp;

/* FLOAD fields. */
#define IRFLDEF(_) \
  _(STR_LEN,	offsetof(GCstr, len)) \
  _(FUNC_ENV,	offsetof(GCfunc, l.env)) \
  _(FUNC_PC,	offsetof(GCfunc, l.pc)) \
  _(FUNC_FFID,	offsetof(GCfunc, l.ffid)) \
  _(THREAD_ENV,	offsetof(lua_State, env)) \
  _(TAB_META,	offsetof(GCtab, metatable)) \
  _(TAB_ARRAY,	offsetof(GCtab, array)) \
  _(TAB_NODE,	offsetof(GCtab, node)) \
  _(TAB_ASIZE,	offsetof(GCtab, asize)) \
  _(TAB_HMASK,	offsetof(GCtab, hmask)) \
  _(TAB_NOMM,	offsetof(GCtab, nomm)) \
  _(UDATA_META,	offsetof(GCudata, metatable)) \
  _(UDATA_UDTYPE, offsetof(GCudata, udtype)) \
  _(UDATA_FILE,	sizeof(GCudata)) \
  _(CDATA_CTYPEID, offsetof(GCcdata, ctypeid)) \
  _(CDATA_PTR,	sizeof(GCcdata)) \
  _(CDATA_INT, sizeof(GCcdata)) \
  _(CDATA_INT64, sizeof(GCcdata)) \
  _(CDATA_INT64_4, sizeof(GCcdata) + 4)

typedef enum {
#define FLENUM(name, ofs)	IRFL_##name,
IRFLDEF(FLENUM)
#undef FLENUM
  IRFL__MAX
} IRFieldID;

/* SLOAD mode bits, stored in op2. */
#define IRSLOAD_PARENT		0x01	/* Coalesce with parent trace. */
#define IRSLOAD_FRAME		0x02	/* Load hiword of frame. */
#define IRSLOAD_TYPECHECK	0x04	/* Needs type check. */
#define IRSLOAD_CONVERT		0x08	/* Number to integer conversion. */
#define IRSLOAD_READONLY	0x10	/* Read-only, omit slot store. */
#define IRSLOAD_INHERIT		0x20	/* Inherited by exits/side traces. */

/* XLOAD mode, stored in op2. */
#define IRXLOAD_READONLY	1	/* Load from read-only data. */
#define IRXLOAD_VOLATILE	2	/* Load from volatile data. */
#define IRXLOAD_UNALIGNED	4	/* Unaligned load. */

/* BUFHDR mode, stored in op2. */
#define IRBUFHDR_RESET		0	/* Reset buffer. */
#define IRBUFHDR_APPEND		1	/* Append to buffer. */

/* CONV mode, stored in op2. */
#define IRCONV_SRCMASK		0x001f	/* Source IRType. */
#define IRCONV_DSTMASK		0x03e0	/* Dest. IRType (also in ir->t). */
#define IRCONV_DSH		5
#define IRCONV_NUM_INT		((IRT_NUM<<IRCONV_DSH)|IRT_INT)
#define IRCONV_INT_NUM		((IRT_INT<<IRCONV_DSH)|IRT_NUM)
#define IRCONV_SEXT		0x0800	/* Sign-extend integer to integer. */
#define IRCONV_MODEMASK		0x0fff
#define IRCONV_CONVMASK		0xf000
#define IRCONV_CSH		12
/* Number to integer conversion mode. Ordered by strength of the checks. */
#define IRCONV_TOBIT  (0<<IRCONV_CSH)	/* None. Cache only: TOBIT conv. */
#define IRCONV_ANY    (1<<IRCONV_CSH)	/* Any FP number is ok. */
#define IRCONV_INDEX  (2<<IRCONV_CSH)	/* Check + special backprop rules. */
#define IRCONV_CHECK  (3<<IRCONV_CSH)	/* Number checked for integerness. */

/* TOSTR mode, stored in op2. */
#define IRTOSTR_INT		0	/* Convert integer to string. */
#define IRTOSTR_NUM		1	/* Convert number to string. */
#define IRTOSTR_CHAR		2	/* Convert char value to string. */

/* -- IR operands --------------------------------------------------------- */

/* IR operand mode (2 bit). */
typedef enum {
  IRMref,		/* IR reference. */
  IRMlit,		/* 16 bit unsigned literal. */
  IRMcst,		/* Constant literal: i, gcr or ptr. */
  IRMnone		/* Unused operand. */
} IRMode;
#define IRM___		IRMnone

/* Mode bits: Commutative, {Normal/Ref, Alloc, Load, Store}, Non-weak guard. */
#define IRM_C			0x10

#define IRM_N			0x00
#define IRM_R			IRM_N
#define IRM_A			0x20
#define IRM_L			0x40
#define IRM_S			0x60

#define IRM_W			0x80

#define IRM_NW			(IRM_N|IRM_W)
#define IRM_CW			(IRM_C|IRM_W)
#define IRM_AW			(IRM_A|IRM_W)
#define IRM_LW			(IRM_L|IRM_W)

#define irm_op1(m)		((IRMode)((m)&3))
#define irm_op2(m)		((IRMode)(((m)>>2)&3))
#define irm_iscomm(m)		((m) & IRM_C)
#define irm_kind(m)		((m) & IRM_S)

#define IRMODE(name, m, m1, m2)	(((IRM##m1)|((IRM##m2)<<2)|(IRM_##m))^IRM_W),

LJ_DATA const uint8_t lj_ir_mode[IR__MAX+1];

/* -- IR instruction types ------------------------------------------------ */

/* Map of itypes to non-negative numbers. ORDER LJ_T.
** LJ_TUPVAL/LJ_TTRACE never appear in a TValue. Use these itypes for
** IRT_P32 and IRT_P64, which never escape the IR.
** The various integers are only used in the IR and can only escape to
** a TValue after implicit or explicit conversion. Their types must be
** contiguous and next to IRT_NUM (see the typerange macros below).
*/
#define IRTDEF(_) \
  _(NIL, 4) _(FALSE, 4) _(TRUE, 4) _(LIGHTUD, LJ_64 ? 8 : 4) _(STR, 4) \
  _(P32, 4) _(THREAD, 4) _(PROTO, 4) _(FUNC, 4) _(P64, 8) _(CDATA, 4) \
  _(TAB, 4) _(UDATA, 4) \
  _(FLOAT, 4) _(NUM, 8) _(I8, 1) _(U8, 1) _(I16, 2) _(U16, 2) \
  _(INT, 4) _(U32, 4) _(I64, 8) _(U64, 8) \
  _(SOFTFP, 4)  /* There is room for 9 more types. */

/* IR result type and flags (8 bit). */
typedef enum {
#define IRTENUM(name, size)	IRT_##name,
IRTDEF(IRTENUM)
#undef IRTENUM
  IRT__MAX,

  /* Native pointer type and the corresponding integer type. */
  IRT_PTR = LJ_64 ? IRT_P64 : IRT_P32,
  IRT_INTP = LJ_64 ? IRT_I64 : IRT_INT,
  IRT_UINTP = LJ_64 ? IRT_U64 : IRT_U32,
  /* TODO_GC64: major changes required for all uses of IRT_P32. */

  /* Additional flags. */
  IRT_MARK = 0x20,	/* Marker for misc. purposes. */
  IRT_ISPHI = 0x40,	/* Instruction is left or right PHI operand. */
  IRT_GUARD = 0x80,	/* Instruction is a guard. */

  /* Masks. */
  IRT_TYPE = 0x1f,
  IRT_T = 0xff
} IRType;

#define irtype_ispri(irt)	((uint32_t)(irt) <= IRT_TRUE)

/* Stored IRType. */
typedef struct IRType1 { uint8_t irt; } IRType1;

#define IRT(o, t)		((uint32_t)(((o)<<8) | (t)))
#define IRTI(o)			(IRT((o), IRT_INT))
#define IRTN(o)			(IRT((o), IRT_NUM))
#define IRTG(o, t)		(IRT((o), IRT_GUARD|(t)))
#define IRTGI(o)		(IRT((o), IRT_GUARD|IRT_INT))

#define irt_t(t)		((IRType)(t).irt)
#define irt_type(t)		((IRType)((t).irt & IRT_TYPE))
#define irt_sametype(t1, t2)	((((t1).irt ^ (t2).irt) & IRT_TYPE) == 0)
#define irt_typerange(t, first, last) \
  ((uint32_t)((t).irt & IRT_TYPE) - (uint32_t)(first) <= (uint32_t)(last-first))

#define irt_isnil(t)		(irt_type(t) == IRT_NIL)
#define irt_ispri(t)		((uint32_t)irt_type(t) <= IRT_TRUE)
#define irt_islightud(t)	(irt_type(t) == IRT_LIGHTUD)
#define irt_isstr(t)		(irt_type(t) == IRT_STR)
#define irt_istab(t)		(irt_type(t) == IRT_TAB)
#define irt_iscdata(t)		(irt_type(t) == IRT_CDATA)
#define irt_isfloat(t)		(irt_type(t) == IRT_FLOAT)
#define irt_isnum(t)		(irt_type(t) == IRT_NUM)
#define irt_isint(t)		(irt_type(t) == IRT_INT)
#define irt_isi8(t)		(irt_type(t) == IRT_I8)
#define irt_isu8(t)		(irt_type(t) == IRT_U8)
#define irt_isi16(t)		(irt_type(t) == IRT_I16)
#define irt_isu16(t)		(irt_type(t) == IRT_U16)
#define irt_isu32(t)		(irt_type(t) == IRT_U32)
#define irt_isi64(t)		(irt_type(t) == IRT_I64)
#define irt_isu64(t)		(irt_type(t) == IRT_U64)

#define irt_isfp(t)		(irt_isnum(t) || irt_isfloat(t))
#define irt_isinteger(t)	(irt_typerange((t), IRT_I8, IRT_INT))
#define irt_isgcv(t)		(irt_typerange((t), IRT_STR, IRT_UDATA))
#define irt_isaddr(t)		(irt_typerange((t), IRT_LIGHTUD, IRT_UDATA))
#define irt_isint64(t)		(irt_typerange((t), IRT_I64, IRT_U64))

#if LJ_GC64
#define IRT_IS64 \
  ((1u<<IRT_NUM)|(1u<<IRT_I64)|(1u<<IRT_U64)|(1u<<IRT_P64)|\
   (1u<<IRT_LIGHTUD)|(1u<<IRT_STR)|(1u<<IRT_THREAD)|(1u<<IRT_PROTO)|\
   (1u<<IRT_FUNC)|(1u<<IRT_CDATA)|(1u<<IRT_TAB)|(1u<<IRT_UDATA))
#elif LJ_64
#define IRT_IS64 \
  ((1u<<IRT_NUM)|(1u<<IRT_I64)|(1u<<IRT_U64)|(1u<<IRT_P64)|(1u<<IRT_LIGHTUD))
#else
#define IRT_IS64 \
  ((1u<<IRT_NUM)|(1u<<IRT_I64)|(1u<<IRT_U64))
#endif

#define irt_is64(t)		((IRT_IS64 >> irt_type(t)) & 1)
#define irt_is64orfp(t)		(((IRT_IS64|(1u<<IRT_FLOAT))>>irt_type(t)) & 1)

#define irt_size(t)		(lj_ir_type_size[irt_t((t))])

LJ_DATA const uint8_t lj_ir_type_size[];

static LJ_AINLINE IRType itype2irt(const TValue *tv)
{
  if (tvisint(tv))
    return IRT_INT;
  else if (tvisnum(tv))
    return IRT_NUM;
#if LJ_64 && !LJ_GC64
  else if (tvislightud(tv))
    return IRT_LIGHTUD;
#endif
  else
    return (IRType)~itype(tv);
}

static LJ_AINLINE uint32_t irt_toitype_(IRType t)
{
  lua_assert(!LJ_64 || t != IRT_LIGHTUD);
  if (LJ_DUALNUM && t > IRT_NUM) {
    return LJ_TISNUM;
  } else {
    lua_assert(t <= IRT_NUM);
    return ~(uint32_t)t;
  }
}

#define irt_toitype(t)		irt_toitype_(irt_type((t)))

#define irt_isguard(t)		((t).irt & IRT_GUARD)
#define irt_ismarked(t)		((t).irt & IRT_MARK)
#define irt_setmark(t)		((t).irt |= IRT_MARK)
#define irt_clearmark(t)	((t).irt &= ~IRT_MARK)
#define irt_isphi(t)		((t).irt & IRT_ISPHI)
#define irt_setphi(t)		((t).irt |= IRT_ISPHI)
#define irt_clearphi(t)		((t).irt &= ~IRT_ISPHI)

/* Stored combined IR opcode and type. */
typedef uint16_t IROpT;

/* -- IR references ------------------------------------------------------- */

/* IR references. */
typedef uint16_t IRRef1;	/* One stored reference. */
typedef uint32_t IRRef2;	/* Two stored references. */
typedef uint32_t IRRef;		/* Used to pass around references. */

/* Fixed references. */
enum {
  REF_BIAS =	0x8000,
  REF_TRUE =	REF_BIAS-3,
  REF_FALSE =	REF_BIAS-2,
  REF_NIL =	REF_BIAS-1,	/* \--- Constants grow downwards. */
  REF_BASE =	REF_BIAS,	/* /--- IR grows upwards. */
  REF_FIRST =	REF_BIAS+1,
  REF_DROP =	0xffff
};

/* Note: IRMlit operands must be < REF_BIAS, too!
** This allows for fast and uniform manipulation of all operands
** without looking up the operand mode in lj_ir_mode:
** - CSE calculates the maximum reference of two operands.
**   This must work with mixed reference/literal operands, too.
** - DCE marking only checks for operand >= REF_BIAS.
** - LOOP needs to substitute reference operands.
**   Constant references and literals must not be modified.
*/

#define IRREF2(lo, hi)		((IRRef2)(lo) | ((IRRef2)(hi) << 16))

#define irref_isk(ref)		((ref) < REF_BIAS)

/* Tagged IR references (32 bit).
**
** +-------+-------+---------------+
** |  irt  | flags |      ref      |
** +-------+-------+---------------+
**
** The tag holds a copy of the IRType and speeds up IR type checks.
*/
typedef uint32_t TRef;

#define TREF_REFMASK		0x0000ffff
#define TREF_FRAME		0x00010000
#define TREF_CONT		0x00020000

#define TREF(ref, t)		((TRef)((ref) + ((t)<<24)))

#define tref_ref(tr)		((IRRef1)(tr))
#define tref_t(tr)		((IRType)((tr)>>24))
#define tref_type(tr)		((IRType)(((tr)>>24) & IRT_TYPE))
#define tref_typerange(tr, first, last) \
  ((((tr)>>24) & IRT_TYPE) - (TRef)(first) <= (TRef)(last-first))

#define tref_istype(tr, t)	(((tr) & (IRT_TYPE<<24)) == ((t)<<24))
#define tref_isnil(tr)		(tref_istype((tr), IRT_NIL))
#define tref_isfalse(tr)	(tref_istype((tr), IRT_FALSE))
#define tref_istrue(tr)		(tref_istype((tr), IRT_TRUE))
#define tref_islightud(tr)	(tref_istype((tr), IRT_LIGHTUD))
#define tref_isstr(tr)		(tref_istype((tr), IRT_STR))
#define tref_isfunc(tr)		(tref_istype((tr), IRT_FUNC))
#define tref_iscdata(tr)	(tref_istype((tr), IRT_CDATA))
#define tref_istab(tr)		(tref_istype((tr), IRT_TAB))
#define tref_isudata(tr)	(tref_istype((tr), IRT_UDATA))
#define tref_isnum(tr)		(tref_istype((tr), IRT_NUM))
#define tref_isint(tr)		(tref_istype((tr), IRT_INT))

#define tref_isbool(tr)		(tref_typerange((tr), IRT_FALSE, IRT_TRUE))
#define tref_ispri(tr)		(tref_typerange((tr), IRT_NIL, IRT_TRUE))
#define tref_istruecond(tr)	(!tref_typerange((tr), IRT_NIL, IRT_FALSE))
#define tref_isinteger(tr)	(tref_typerange((tr), IRT_I8, IRT_INT))
#define tref_isnumber(tr)	(tref_typerange((tr), IRT_NUM, IRT_INT))
#define tref_isnumber_str(tr)	(tref_isnumber((tr)) || tref_isstr((tr)))
#define tref_isgcv(tr)		(tref_typerange((tr), IRT_STR, IRT_UDATA))

#define tref_isk(tr)		(irref_isk(tref_ref((tr))))
#define tref_isk2(tr1, tr2)	(irref_isk(tref_ref((tr1) | (tr2))))

#define TREF_PRI(t)		(TREF(REF_NIL-(t), (t)))
#define TREF_NIL		(TREF_PRI(IRT_NIL))
#define TREF_FALSE		(TREF_PRI(IRT_FALSE))
#define TREF_TRUE		(TREF_PRI(IRT_TRUE))

/* -- IR format ----------------------------------------------------------- */

/* IR instruction format (64 bit).
**
**    16      16     8   8   8   8
** +-------+-------+---+---+---+---+
** |  op1  |  op2  | t | o | r | s |
** +-------+-------+---+---+---+---+
** |  op12/i/gco   |   ot  | prev  | (alternative fields in union)
** +---------------+-------+-------+
**        32           16      16
**
** prev is only valid prior to register allocation and then reused for r + s.
*/

typedef union IRIns {
  struct {
    LJ_ENDIAN_LOHI(
      IRRef1 op1;	/* IR operand 1. */
    , IRRef1 op2;	/* IR operand 2. */
    )
    IROpT ot;		/* IR opcode and type (overlaps t and o). */
    IRRef1 prev;	/* Previous ins in same chain (overlaps r and s). */
  };
  struct {
    IRRef2 op12;	/* IR operand 1 and 2 (overlaps op1 and op2). */
    LJ_ENDIAN_LOHI(
      IRType1 t;	/* IR type. */
    , IROp1 o;		/* IR opcode. */
    )
    LJ_ENDIAN_LOHI(
      uint8_t r;	/* Register allocation (overlaps prev). */
    , uint8_t s;	/* Spill slot allocation (overlaps prev). */
    )
  };
  int32_t i;		/* 32 bit signed integer literal (overlaps op12). */
  GCRef gcr;		/* GCobj constant (overlaps op12). */
  MRef ptr;		/* Pointer constant (overlaps op12). */
} IRIns;

/* TODO_GC64: major changes required. */
#define ir_kgc(ir)	check_exp((ir)->o == IR_KGC, gcref((ir)->gcr))
#define ir_kstr(ir)	(gco2str(ir_kgc((ir))))
#define ir_ktab(ir)	(gco2tab(ir_kgc((ir))))
#define ir_kfunc(ir)	(gco2func(ir_kgc((ir))))
#define ir_kcdata(ir)	(gco2cd(ir_kgc((ir))))
#define ir_knum(ir)	check_exp((ir)->o == IR_KNUM, mref((ir)->ptr, cTValue))
#define ir_kint64(ir)	check_exp((ir)->o == IR_KINT64, mref((ir)->ptr,cTValue))
#define ir_k64(ir) \
  check_exp((ir)->o == IR_KNUM || (ir)->o == IR_KINT64, mref((ir)->ptr,cTValue))
#define ir_kptr(ir) \
  check_exp((ir)->o == IR_KPTR || (ir)->o == IR_KKPTR, mref((ir)->ptr, void))

/* A store or any other op with a non-weak guard has a side-effect. */
static LJ_AINLINE int ir_sideeff(IRIns *ir)
{
  return (((ir->t.irt | ~IRT_GUARD) & lj_ir_mode[ir->o]) >= IRM_S);
}

LJ_STATIC_ASSERT((int)IRT_GUARD == (int)IRM_W);

#endif
