1 files changed, 218 insertions, 50 deletions

diff --git a/src/lj_opt_fold.c b/src/lj_opt_fold.c
index fe37b98a..1d37a7fd 100644
--- a/src/lj_opt_fold.c
+++ b/src/lj_opt_fold.c
@@ -14,18 +14,21 @@
 
 #if LJ_HASJIT
 
+#include "lj_buf.h"
 #include "lj_str.h"
 #include "lj_tab.h"
 #include "lj_ir.h"
 #include "lj_jit.h"
+#include "lj_ircall.h"
 #include "lj_iropt.h"
 #include "lj_trace.h"
 #if LJ_HASFFI
 #include "lj_ctype.h"
-#endif
 #include "lj_carith.h"
+#endif
 #include "lj_vm.h"
 #include "lj_strscan.h"
+#include "lj_strfmt.h"
 
 /* Here's a short description how the FOLD engine processes instructions:
 **
@@ -155,13 +158,14 @@ typedef IRRef (LJ_FASTCALL *FoldFunc)(jit_State *J);
 
 /* Barrier to prevent folding across a GC step.
 ** GC steps can only happen at the head of a trace and at LOOP.
-** And the GC is only driven forward if there is at least one allocation.
+** And the GC is only driven forward if there's at least one allocation.
 */
 #define gcstep_barrier(J, ref) \
   ((ref) < J->chain[IR_LOOP] && \
    (J->chain[IR_SNEW] || J->chain[IR_XSNEW] || \
     J->chain[IR_TNEW] || J->chain[IR_TDUP] || \
-    J->chain[IR_CNEW] || J->chain[IR_CNEWI] || J->chain[IR_TOSTR]))
+    J->chain[IR_CNEW] || J->chain[IR_CNEWI] || \
+    J->chain[IR_BUFSTR] || J->chain[IR_TOSTR]))
 
 /* -- Constant folding for FP numbers ------------------------------------- */
 
@@ -336,11 +340,9 @@ LJFOLDF(kfold_intcomp0)
 static uint64_t kfold_int64arith(uint64_t k1, uint64_t k2, IROp op)
 {
   switch (op) {
-#if LJ_64 || LJ_HASFFI
+#if LJ_HASFFI
   case IR_ADD: k1 += k2; break;
   case IR_SUB: k1 -= k2; break;
-#endif
-#if LJ_HASFFI
   case IR_MUL: k1 *= k2; break;
   case IR_BAND: k1 &= k2; break;
   case IR_BOR: k1 |= k2; break;
@@ -392,20 +394,10 @@ LJFOLD(BROL KINT64 KINT)
 LJFOLD(BROR KINT64 KINT)
 LJFOLDF(kfold_int64shift)
 {
-#if LJ_HASFFI || LJ_64
+#if LJ_HASFFI
   uint64_t k = ir_k64(fleft)->u64;
   int32_t sh = (fright->i & 63);
-  switch ((IROp)fins->o) {
-  case IR_BSHL: k <<= sh; break;
-#if LJ_HASFFI
-  case IR_BSHR: k >>= sh; break;
-  case IR_BSAR: k = (uint64_t)((int64_t)k >> sh); break;
-  case IR_BROL: k = lj_rol(k, sh); break;
-  case IR_BROR: k = lj_ror(k, sh); break;
-#endif
-  default: lua_assert(0); break;
-  }
-  return INT64FOLD(k);
+  return INT64FOLD(lj_carith_shift64(k, sh, fins->o - IR_BSHL));
 #else
   UNUSED(J); lua_assert(0); return FAILFOLD;
 #endif
@@ -527,6 +519,179 @@ LJFOLDF(kfold_strcmp)
   return NEXTFOLD;
 }
 
+/* -- Constant folding and forwarding for buffers ------------------------- */
+
+/*
+** Buffer ops perform stores, but their effect is limited to the buffer
+** itself. Also, buffer ops are chained: a use of an op implies a use of
+** all other ops up the chain. Conversely, if an op is unused, all ops
+** up the chain can go unsed. This largely eliminates the need to treat
+** them as stores.
+**
+** Alas, treating them as normal (IRM_N) ops doesn't work, because they
+** cannot be CSEd in isolation. CSE for IRM_N is implicitly done in LOOP
+** or if FOLD is disabled.
+**
+** The compromise is to declare them as loads, emit them like stores and
+** CSE whole chains manually when the BUFSTR is to be emitted. Any chain
+** fragments left over from CSE are eliminated by DCE.
+*/
+
+/* BUFHDR is emitted like a store, see below. */
+
+LJFOLD(BUFPUT BUFHDR BUFSTR)
+LJFOLDF(bufput_append)
+{
+  /* New buffer, no other buffer op inbetween and same buffer? */
+  if ((J->flags & JIT_F_OPT_FWD) &&
+      !(fleft->op2 & IRBUFHDR_APPEND) &&
+      fleft->prev == fright->op2 &&
+      fleft->op1 == IR(fright->op2)->op1) {
+    IRRef ref = fins->op1;
+    IR(ref)->op2 = (fleft->op2 | IRBUFHDR_APPEND);  /* Modify BUFHDR. */
+    IR(ref)->op1 = fright->op1;
+    return ref;
+  }
+  return EMITFOLD;  /* Always emit, CSE later. */
+}
+
+LJFOLD(BUFPUT any any)
+LJFOLDF(bufput_kgc)
+{
+  if (LJ_LIKELY(J->flags & JIT_F_OPT_FOLD) && fright->o == IR_KGC) {
+    GCstr *s2 = ir_kstr(fright);
+    if (s2->len == 0) {  /* Empty string? */
+      return LEFTFOLD;
+    } else {
+      if (fleft->o == IR_BUFPUT && irref_isk(fleft->op2) &&
+          !irt_isphi(fleft->t)) {  /* Join two constant string puts in a row. */
+        GCstr *s1 = ir_kstr(IR(fleft->op2));
+        IRRef kref = lj_ir_kstr(J, lj_buf_cat2str(J->L, s1, s2));
+        /* lj_ir_kstr() may realloc the IR and invalidates any IRIns *. */
+        IR(fins->op1)->op2 = kref;  /* Modify previous BUFPUT. */
+        return fins->op1;
+      }
+    }
+  }
+  return EMITFOLD;  /* Always emit, CSE later. */
+}
+
+LJFOLD(BUFSTR any any)
+LJFOLDF(bufstr_kfold_cse)
+{
+  lua_assert(fleft->o == IR_BUFHDR || fleft->o == IR_BUFPUT ||
+             fleft->o == IR_CALLL);
+  if (LJ_LIKELY(J->flags & JIT_F_OPT_FOLD)) {
+    if (fleft->o == IR_BUFHDR) {  /* No put operations? */
+      if (!(fleft->op2 & IRBUFHDR_APPEND))  /* Empty buffer? */
+        return lj_ir_kstr(J, &J2G(J)->strempty);
+      fins->op1 = fleft->prev;  /* Relies on checks in bufput_append. */
+      return CSEFOLD;
+    } else if (fleft->o == IR_BUFPUT) {
+      IRIns *irb = IR(fleft->op1);
+      if (irb->o == IR_BUFHDR && !(irb->op2 & IRBUFHDR_APPEND))
+        return fleft->op2;  /* Shortcut for a single put operation. */
+    }
+  }
+  /* Try to CSE the whole chain. */
+  if (LJ_LIKELY(J->flags & JIT_F_OPT_CSE)) {
+    IRRef ref = J->chain[IR_BUFSTR];
+    while (ref) {
+      IRIns *irs = IR(ref), *ira = fleft, *irb = IR(irs->op1);
+      while (ira->o == irb->o && ira->op2 == irb->op2) {
+        lua_assert(ira->o == IR_BUFHDR || ira->o == IR_BUFPUT ||
+                   ira->o == IR_CALLL || ira->o == IR_CARG);
+        if (ira->o == IR_BUFHDR && !(ira->op2 & IRBUFHDR_APPEND))
+          return ref;  /* CSE succeeded. */
+        if (ira->o == IR_CALLL && ira->op2 == IRCALL_lj_buf_puttab)
+          break;
+        ira = IR(ira->op1);
+        irb = IR(irb->op1);
+      }
+      ref = irs->prev;
+    }
+  }
+  return EMITFOLD;  /* No CSE possible. */
+}
+
+LJFOLD(CALLL CARG IRCALL_lj_buf_putstr_reverse)
+LJFOLD(CALLL CARG IRCALL_lj_buf_putstr_upper)
+LJFOLD(CALLL CARG IRCALL_lj_buf_putstr_lower)
+LJFOLD(CALLL CARG IRCALL_lj_strfmt_putquoted)
+LJFOLDF(bufput_kfold_op)
+{
+  if (irref_isk(fleft->op2)) {
+    const CCallInfo *ci = &lj_ir_callinfo[fins->op2];
+    SBuf *sb = lj_buf_tmp_(J->L);
+    sb = ((SBuf * (LJ_FASTCALL *)(SBuf *, GCstr *))ci->func)(sb,
+                                                       ir_kstr(IR(fleft->op2)));
+    fins->o = IR_BUFPUT;
+    fins->op1 = fleft->op1;
+    fins->op2 = lj_ir_kstr(J, lj_buf_tostr(sb));
+    return RETRYFOLD;
+  }
+  return EMITFOLD;  /* Always emit, CSE later. */
+}
+
+LJFOLD(CALLL CARG IRCALL_lj_buf_putstr_rep)
+LJFOLDF(bufput_kfold_rep)
+{
+  if (irref_isk(fleft->op2)) {
+    IRIns *irc = IR(fleft->op1);
+    if (irref_isk(irc->op2)) {
+      SBuf *sb = lj_buf_tmp_(J->L);
+      sb = lj_buf_putstr_rep(sb, ir_kstr(IR(irc->op2)), IR(fleft->op2)->i);
+      fins->o = IR_BUFPUT;
+      fins->op1 = irc->op1;
+      fins->op2 = lj_ir_kstr(J, lj_buf_tostr(sb));
+      return RETRYFOLD;
+    }
+  }
+  return EMITFOLD;  /* Always emit, CSE later. */
+}
+
+LJFOLD(CALLL CARG IRCALL_lj_strfmt_putfxint)
+LJFOLD(CALLL CARG IRCALL_lj_strfmt_putfnum_int)
+LJFOLD(CALLL CARG IRCALL_lj_strfmt_putfnum_uint)
+LJFOLD(CALLL CARG IRCALL_lj_strfmt_putfnum)
+LJFOLD(CALLL CARG IRCALL_lj_strfmt_putfstr)
+LJFOLD(CALLL CARG IRCALL_lj_strfmt_putfchar)
+LJFOLDF(bufput_kfold_fmt)
+{
+  IRIns *irc = IR(fleft->op1);
+  lua_assert(irref_isk(irc->op2));  /* SFormat must be const. */
+  if (irref_isk(fleft->op2)) {
+    SFormat sf = (SFormat)IR(irc->op2)->i;
+    IRIns *ira = IR(fleft->op2);
+    SBuf *sb = lj_buf_tmp_(J->L);
+    switch (fins->op2) {
+    case IRCALL_lj_strfmt_putfxint:
+      sb = lj_strfmt_putfxint(sb, sf, ir_k64(ira)->u64);
+      break;
+    case IRCALL_lj_strfmt_putfstr:
+      sb = lj_strfmt_putfstr(sb, sf, ir_kstr(ira));
+      break;
+    case IRCALL_lj_strfmt_putfchar:
+      sb = lj_strfmt_putfchar(sb, sf, ira->i);
+      break;
+    case IRCALL_lj_strfmt_putfnum_int:
+    case IRCALL_lj_strfmt_putfnum_uint:
+    case IRCALL_lj_strfmt_putfnum:
+    default: {
+      const CCallInfo *ci = &lj_ir_callinfo[fins->op2];
+      sb = ((SBuf * (*)(SBuf *, SFormat, lua_Number))ci->func)(sb, sf,
+                                                         ir_knum(ira)->n);
+      break;
+      }
+    }
+    fins->o = IR_BUFPUT;
+    fins->op1 = irc->op1;
+    fins->op2 = lj_ir_kstr(J, lj_buf_tostr(sb));
+    return RETRYFOLD;
+  }
+  return EMITFOLD;  /* Always emit, CSE later. */
+}
+
 /* -- Constant folding of pointer arithmetic ------------------------------ */
 
 LJFOLD(ADD KGC KINT)
@@ -647,27 +812,22 @@ LJFOLD(CONV KNUM IRCONV_INT_NUM)
 LJFOLDF(kfold_conv_knum_int_num)
 {
   lua_Number n = knumleft;
-  if (!(fins->op2 & IRCONV_TRUNC)) {
-    int32_t k = lj_num2int(n);
-    if (irt_isguard(fins->t) && n != (lua_Number)k) {
-      /* We're about to create a guard which always fails, like CONV +1.5.
-      ** Some pathological loops cause this during LICM, e.g.:
-      **   local x,k,t = 0,1.5,{1,[1.5]=2}
-      **   for i=1,200 do x = x+ t[k]; k = k == 1 and 1.5 or 1 end
-      **   assert(x == 300)
-      */
-      return FAILFOLD;
-    }
-    return INTFOLD(k);
-  } else {
-    return INTFOLD((int32_t)n);
+  int32_t k = lj_num2int(n);
+  if (irt_isguard(fins->t) && n != (lua_Number)k) {
+    /* We're about to create a guard which always fails, like CONV +1.5.
+    ** Some pathological loops cause this during LICM, e.g.:
+    **   local x,k,t = 0,1.5,{1,[1.5]=2}
+    **   for i=1,200 do x = x+ t[k]; k = k == 1 and 1.5 or 1 end
+    **   assert(x == 300)
+    */
+    return FAILFOLD;
   }
+  return INTFOLD(k);
 }
 
 LJFOLD(CONV KNUM IRCONV_U32_NUM)
 LJFOLDF(kfold_conv_knum_u32_num)
 {
-  lua_assert((fins->op2 & IRCONV_TRUNC));
 #ifdef _MSC_VER
   {  /* Workaround for MSVC bug. */
     volatile uint32_t u = (uint32_t)knumleft;
@@ -681,27 +841,27 @@ LJFOLDF(kfold_conv_knum_u32_num)
 LJFOLD(CONV KNUM IRCONV_I64_NUM)
 LJFOLDF(kfold_conv_knum_i64_num)
 {
-  lua_assert((fins->op2 & IRCONV_TRUNC));
   return INT64FOLD((uint64_t)(int64_t)knumleft);
 }
 
 LJFOLD(CONV KNUM IRCONV_U64_NUM)
 LJFOLDF(kfold_conv_knum_u64_num)
 {
-  lua_assert((fins->op2 & IRCONV_TRUNC));
   return INT64FOLD(lj_num2u64(knumleft));
 }
 
-LJFOLD(TOSTR KNUM)
+LJFOLD(TOSTR KNUM any)
 LJFOLDF(kfold_tostr_knum)
 {
-  return lj_ir_kstr(J, lj_str_fromnum(J->L, &knumleft));
+  return lj_ir_kstr(J, lj_strfmt_num(J->L, ir_knum(fleft)));
 }
 
-LJFOLD(TOSTR KINT)
+LJFOLD(TOSTR KINT any)
 LJFOLDF(kfold_tostr_kint)
 {
-  return lj_ir_kstr(J, lj_str_fromint(J->L, fleft->i));
+  return lj_ir_kstr(J, fins->op2 == IRTOSTR_INT ?
+                       lj_strfmt_int(J->L, fleft->i) :
+                       lj_strfmt_char(J->L, fleft->i));
 }
 
 LJFOLD(STRTO KGC)
@@ -1199,7 +1359,9 @@ static TRef simplify_intmul_k(jit_State *J, int32_t k)
   ** But this is mainly intended for simple address arithmetic.
   ** Also it's easier for the backend to optimize the original multiplies.
   */
-  if (k == 1) {  /* i * 1 ==> i */
+  if (k == 0) {  /* i * 0 ==> 0 */
+    return RIGHTFOLD;
+  } else if (k == 1) {  /* i * 1 ==> i */
     return LEFTFOLD;
   } else if ((k & (k-1)) == 0) {  /* i * 2^k ==> i << k */
     fins->o = IR_BSHL;
@@ -1212,9 +1374,7 @@ static TRef simplify_intmul_k(jit_State *J, int32_t k)
 LJFOLD(MUL any KINT)
 LJFOLDF(simplify_intmul_k32)
 {
-  if (fright->i == 0)  /* i * 0 ==> 0 */
-    return INTFOLD(0);
-  else if (fright->i > 0)
+  if (fright->i >= 0)
     return simplify_intmul_k(J, fright->i);
   return NEXTFOLD;
 }
@@ -1222,14 +1382,13 @@ LJFOLDF(simplify_intmul_k32)
 LJFOLD(MUL any KINT64)
 LJFOLDF(simplify_intmul_k64)
 {
-  if (ir_kint64(fright)->u64 == 0)  /* i * 0 ==> 0 */
-    return INT64FOLD(0);
-#if LJ_64
-  /* NYI: SPLIT for BSHL and 32 bit backend support. */
-  else if (ir_kint64(fright)->u64 < 0x80000000u)
+#if LJ_HASFFI
+  if (ir_kint64(fright)->u64 < 0x80000000u)
     return simplify_intmul_k(J, (int32_t)ir_kint64(fright)->u64);
-#endif
   return NEXTFOLD;
+#else
+  UNUSED(J); lua_assert(0); return FAILFOLD;
+#endif
 }
 
 LJFOLD(MOD any KINT)
@@ -1529,7 +1688,7 @@ LJFOLD(BOR BOR KINT64)
 LJFOLD(BXOR BXOR KINT64)
 LJFOLDF(reassoc_intarith_k64)
 {
-#if LJ_HASFFI || LJ_64
+#if LJ_HASFFI
   IRIns *irk = IR(fleft->op2);
   if (irk->o == IR_KINT64) {
     uint64_t k = kfold_int64arith(ir_k64(irk)->u64,
@@ -2007,6 +2166,14 @@ LJFOLDF(fload_str_len_snew)
   return NEXTFOLD;
 }
 
+LJFOLD(FLOAD TOSTR IRFL_STR_LEN)
+LJFOLDF(fload_str_len_tostr)
+{
+  if (LJ_LIKELY(J->flags & JIT_F_OPT_FOLD) && fleft->op2 == IRTOSTR_CHAR)
+    return INTFOLD(1);
+  return NEXTFOLD;
+}
+
 /* The C type ID of cdata objects is immutable. */
 LJFOLD(FLOAD KGC IRFL_CDATA_CTYPEID)
 LJFOLDF(fload_cdata_typeid_kgc)
@@ -2149,6 +2316,7 @@ LJFOLD(TNEW any any)
 LJFOLD(TDUP any)
 LJFOLD(CNEW any any)
 LJFOLD(XSNEW any any)
+LJFOLD(BUFHDR any any)
 LJFOLDX(lj_ir_emit)
 
 /* ------------------------------------------------------------------------ */