From a7d1dbacb19c3e5d0c4888cdf59913693e4648b6 Mon Sep 17 00:00:00 2001 From: Mike Pall Date: Tue, 9 Oct 2012 21:49:08 +0200 Subject: [PATCH] FFI: Optimize ffi.copy() and ffi.fill(). --- src/lj_crecord.c | 287 ++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 261 insertions(+), 26 deletions(-) diff --git a/src/lj_crecord.c b/src/lj_crecord.c index fbb5d79a..47ae65b4 100644 --- a/src/lj_crecord.c +++ b/src/lj_crecord.c @@ -91,25 +91,7 @@ static CTypeID argv2ctype(jit_State *J, TRef tr, cTValue *o) } } -/* -- Convert C type to C type -------------------------------------------- */ - -/* -** This code mirrors the code in lj_cconv.c. It performs the same steps -** for the trace recorder that lj_cconv.c does for the interpreter. -** -** One major difference is that we can get away with much fewer checks -** here. E.g. checks for casts, constness or correct types can often be -** omitted, even if they might fail. The interpreter subsequently throws -** an error, which aborts the trace. -** -** All operations are specialized to their C types, so the on-trace -** outcome must be the same as the outcome in the interpreter. If the -** interpreter doesn't throw an error, then the trace is correct, too. -** Care must be taken not to generate invalid (temporary) IR or to -** trigger asserts. -*/ - -/* Convert CType to IRType. */ +/* Convert CType to IRType (if possible). */ static IRType crec_ct2irt(CTState *cts, CType *ct) { if (ctype_isenum(ct->info)) ct = ctype_child(cts, ct); @@ -135,6 +117,253 @@ static IRType crec_ct2irt(CTState *cts, CType *ct) return IRT_CDATA; } +/* -- Optimized memory fill and copy -------------------------------------- */ + +/* Maximum length and unroll of inlined copy/fill. */ +#define CREC_COPY_MAXUNROLL 16 +#define CREC_COPY_MAXLEN 128 + +#define CREC_FILL_MAXUNROLL 16 +#if LJ_TARGET_UNALIGNED +#define CREC_FILL_MAXLEN (CTSIZE_PTR * CREC_FILL_MAXUNROLL) +#else +#define CREC_FILL_MAXLEN CREC_FILL_MAXUNROLL +#endif + +/* Number of windowed registers used for optimized memory copy. */ +#if LJ_TARGET_X86 +#define CREC_COPY_REGWIN 2 +#elif LJ_TARGET_PPC || LJ_TARGET_MIPS +#define CREC_COPY_REGWIN 8 +#else +#define CREC_COPY_REGWIN 4 +#endif + +/* List of memory offsets for copy/fill. */ +typedef struct CRecMemList { + CTSize ofs; /* Offset in bytes. */ + IRType tp; /* Type of load/store. */ + TRef trofs; /* TRef of interned offset. */ + TRef trval; /* TRef of load value. */ +} CRecMemList; + +/* Generate copy list for element-wise struct copy. */ +static MSize crec_copy_struct(CRecMemList *ml, CTState *cts, CType *ct) +{ + CTypeID fid = ct->sib; + MSize mlp = 0; + while (fid) { + CType *df = ctype_get(cts, fid); + fid = df->sib; + if (ctype_isfield(df->info)) { + CType *cct; + IRType tp; + if (!gcref(df->name)) continue; /* Ignore unnamed fields. */ + cct = ctype_rawchild(cts, df); /* Field type. */ + tp = crec_ct2irt(cts, cct); + if (tp == IRT_CDATA) return 0; /* NYI: aggregates. */ + if (mlp >= CREC_COPY_MAXUNROLL) return 0; + ml[mlp].ofs = df->size; + ml[mlp].tp = tp; + mlp++; + if (ctype_iscomplex(cct->info)) { + if (mlp >= CREC_COPY_MAXUNROLL) return 0; + ml[mlp].ofs = df->size + (cct->size >> 1); + ml[mlp].tp = tp; + mlp++; + } + } else if (!ctype_isconstval(df->info)) { + /* NYI: bitfields and sub-structures. */ + return 0; + } + } + return mlp; +} + +/* Generate unrolled copy list, from highest to lowest step size/alignment. */ +static MSize crec_copy_unroll(CRecMemList *ml, CTSize len, CTSize step, + IRType tp) +{ + CTSize ofs = 0; + MSize mlp = 0; + if (tp == IRT_CDATA) tp = IRT_U8 + 2*lj_fls(step); + do { + while (ofs + step <= len) { + if (mlp >= CREC_COPY_MAXUNROLL) return 0; + ml[mlp].ofs = ofs; + ml[mlp].tp = tp; + mlp++; + ofs += step; + } + step >>= 1; + tp -= 2; + } while (ofs < len); + return mlp; +} + +/* +** Emit copy list with windowed loads/stores. +** LJ_TARGET_UNALIGNED: may emit unaligned loads/stores (not marked as such). +*/ +static void crec_copy_emit(jit_State *J, CRecMemList *ml, MSize mlp, + TRef trdst, TRef trsrc) +{ + MSize i, j, rwin = 0; + for (i = 0, j = 0; i < mlp; ) { + TRef trofs = lj_ir_kintp(J, ml[i].ofs); + TRef trsptr = emitir(IRT(IR_ADD, IRT_PTR), trsrc, trofs); + ml[i].trval = emitir(IRT(IR_XLOAD, ml[i].tp), trsptr, 0); + ml[i].trofs = trofs; + i++; + rwin += (LJ_SOFTFP && ml[i].tp == IRT_NUM) ? 2 : 1; + if (rwin >= CREC_COPY_REGWIN || i >= mlp) { /* Flush buffered stores. */ + rwin = 0; + for ( ; j < i; j++) { + TRef trdptr = emitir(IRT(IR_ADD, IRT_PTR), trdst, ml[j].trofs); + emitir(IRT(IR_XSTORE, ml[j].tp), trdptr, ml[j].trval); + } + } + } +} + +/* Optimized memory copy. */ +static void crec_copy(jit_State *J, TRef trdst, TRef trsrc, TRef trlen, + CType *ct) +{ + if (tref_isk(trlen)) { /* Length must be constant. */ + CRecMemList ml[CREC_COPY_MAXUNROLL]; + MSize mlp = 0; + CTSize step = 1, len = (CTSize)IR(tref_ref(trlen))->i; + IRType tp = IRT_CDATA; + int needxbar = 0; + if (len == 0) return; /* Shortcut. */ + if (len > CREC_COPY_MAXLEN) goto fallback; + if (ct) { + CTState *cts = ctype_ctsG(J2G(J)); + lua_assert(ctype_isarray(ct->info) || ctype_isstruct(ct->info)); + if (ctype_isarray(ct->info)) { + CType *cct = ctype_rawchild(cts, ct); + tp = crec_ct2irt(cts, cct); + if (tp == IRT_CDATA) goto rawcopy; + step = lj_ir_type_size[tp]; + lua_assert((len & (step-1)) == 0); + } else if ((ct->info & CTF_UNION)) { + step = (1u << ctype_align(ct->info)); + goto rawcopy; + } else { + mlp = crec_copy_struct(ml, cts, ct); + goto emitcopy; + } + } else { + rawcopy: + needxbar = 1; + if (LJ_TARGET_UNALIGNED || step >= CTSIZE_PTR) + step = CTSIZE_PTR; + } + mlp = crec_copy_unroll(ml, len, step, tp); + emitcopy: + if (mlp) { + crec_copy_emit(J, ml, mlp, trdst, trsrc); + if (needxbar) + emitir(IRT(IR_XBAR, IRT_NIL), 0, 0); + return; + } + } +fallback: + /* Call memcpy. Always needs a barrier to disable alias analysis. */ + lj_ir_call(J, IRCALL_memcpy, trdst, trsrc, trlen); + emitir(IRT(IR_XBAR, IRT_NIL), 0, 0); +} + +/* Generate unrolled fill list, from highest to lowest step size/alignment. */ +static MSize crec_fill_unroll(CRecMemList *ml, CTSize len, CTSize step) +{ + CTSize ofs = 0; + MSize mlp = 0; + IRType tp = IRT_U8 + 2*lj_fls(step); + do { + while (ofs + step <= len) { + if (mlp >= CREC_COPY_MAXUNROLL) return 0; + ml[mlp].ofs = ofs; + ml[mlp].tp = tp; + mlp++; + ofs += step; + } + step >>= 1; + tp -= 2; + } while (ofs < len); + return mlp; +} + +/* +** Emit stores for fill list. +** LJ_TARGET_UNALIGNED: may emit unaligned stores (not marked as such). +*/ +static void crec_fill_emit(jit_State *J, CRecMemList *ml, MSize mlp, + TRef trdst, TRef trfill) +{ + MSize i; + for (i = 0; i < mlp; i++) { + TRef trofs = lj_ir_kintp(J, ml[i].ofs); + TRef trdptr = emitir(IRT(IR_ADD, IRT_PTR), trdst, trofs); + emitir(IRT(IR_XSTORE, ml[i].tp), trdptr, trfill); + } +} + +/* Optimized memory fill. */ +static void crec_fill(jit_State *J, TRef trdst, TRef trlen, TRef trfill, + CTSize step) +{ + if (tref_isk(trlen)) { /* Length must be constant. */ + CRecMemList ml[CREC_FILL_MAXUNROLL]; + MSize mlp; + CTSize len = (CTSize)IR(tref_ref(trlen))->i; + if (len == 0) return; /* Shortcut. */ + if (len > CREC_FILL_MAXLEN) goto fallback; + if (LJ_TARGET_UNALIGNED || step >= CTSIZE_PTR) + step = CTSIZE_PTR; + mlp = crec_fill_unroll(ml, len, step); + if (!mlp) goto fallback; + if (tref_isk(trfill) || ml[0].tp != IRT_U8) + trfill = emitconv(trfill, IRT_INT, IRT_U8, 0); + if (ml[0].tp != IRT_U8) { /* Scatter U8 to U16/U32/U64. */ + if (CTSIZE_PTR == 8 && ml[0].tp == IRT_U64) { + if (tref_isk(trfill)) /* Pointless on x64 with zero-extended regs. */ + trfill = emitconv(trfill, IRT_U64, IRT_U32, 0); + trfill = emitir(IRT(IR_MUL, IRT_U64), trfill, + lj_ir_kint64(J, U64x(01010101,01010101))); + } else { + trfill = emitir(IRTI(IR_MUL), trfill, + lj_ir_kint(J, ml[0].tp == IRT_U16 ? 0x0101 : 0x01010101)); + } + } + crec_fill_emit(J, ml, mlp, trdst, trfill); + } else { +fallback: + /* Call memset. Always needs a barrier to disable alias analysis. */ + lj_ir_call(J, IRCALL_memset, trdst, trfill, trlen); /* Note: arg order! */ + } + emitir(IRT(IR_XBAR, IRT_NIL), 0, 0); +} + +/* -- Convert C type to C type -------------------------------------------- */ + +/* +** This code mirrors the code in lj_cconv.c. It performs the same steps +** for the trace recorder that lj_cconv.c does for the interpreter. +** +** One major difference is that we can get away with much fewer checks +** here. E.g. checks for casts, constness or correct types can often be +** omitted, even if they might fail. The interpreter subsequently throws +** an error, which aborts the trace. +** +** All operations are specialized to their C types, so the on-trace +** outcome must be the same as the outcome in the interpreter. If the +** interpreter doesn't throw an error, then the trace is correct, too. +** Care must be taken not to generate invalid (temporary) IR or to +** trigger asserts. +*/ + /* Determine whether a passed number or cdata number is non-zero. */ static int crec_isnonzero(CType *s, void *p) { @@ -1298,26 +1527,32 @@ void LJ_FASTCALL recff_ffi_copy(jit_State *J, RecordFFData *rd) trlen = emitir(IRTI(IR_FLOAD), J->base[1], IRFL_STR_LEN); trlen = emitir(IRTI(IR_ADD), trlen, lj_ir_kint(J, 1)); } - lj_ir_call(J, IRCALL_memcpy, trdst, trsrc, trlen); - emitir(IRT(IR_XBAR, IRT_NIL), 0, 0); rd->nres = 0; + crec_copy(J, trdst, trsrc, trlen, NULL); } /* else: interpreter will throw. */ } void LJ_FASTCALL recff_ffi_fill(jit_State *J, RecordFFData *rd) { CTState *cts = ctype_ctsG(J2G(J)); - TRef tr = J->base[0], trlen = J->base[1], trfill = J->base[2]; - if (tr && trlen) { - tr = crec_ct_tv(J, ctype_get(cts, CTID_P_VOID), 0, tr, &rd->argv[0]); + TRef trdst = J->base[0], trlen = J->base[1], trfill = J->base[2]; + if (trdst && trlen) { + CTSize step = 1; + if (tviscdata(&rd->argv[0])) { /* Get alignment of original destination. */ + CTSize sz; + CType *ct = ctype_raw(cts, cdataV(&rd->argv[0])->ctypeid); + if (ctype_isptr(ct->info)) + ct = ctype_rawchild(cts, ct); + step = (1u<argv[0]); trlen = crec_toint(J, cts, trlen, &rd->argv[1]); if (trfill) trfill = crec_toint(J, cts, trfill, &rd->argv[2]); else trfill = lj_ir_kint(J, 0); - lj_ir_call(J, IRCALL_memset, tr, trfill, trlen); - emitir(IRT(IR_XBAR, IRT_NIL), 0, 0); rd->nres = 0; + crec_fill(J, trdst, trlen, trfill, step); } /* else: interpreter will throw. */ }