ghelpers.c

The Valgrind distribution has multiple tools. The most popular is the memory checking tool (called M

	 //      case AMD64G_CC_OP_SUBW:
	 //         return ((UInt)(cc_dep1 & 0xFFFF)) < ((UInt)(cc_dep2 & 0xFFFF))
	 //                   ? AMD64G_CC_MASK_C : 0;
	 //      case AMD64G_CC_OP_SUBB:
	 //         return ((UInt)(cc_dep1 & 0xFF)) < ((UInt)(cc_dep2 & 0xFF))
	 //                   ? AMD64G_CC_MASK_C : 0;
	 //      case AMD64G_CC_OP_INCL:
	 //      case AMD64G_CC_OP_DECL:
	 //         return cc_ndep & AMD64G_CC_MASK_C;
      default: 
         break;
   }

#  if PROFILE_RFLAGS
   tabc_fast[cc_op]--;
   tabc_slow[cc_op]++;
#  endif

   return amd64g_calculate_rflags_all_WRK(cc_op,cc_dep1,cc_dep2,cc_ndep) 
          & AMD64G_CC_MASK_C;
}


/* CALLED FROM GENERATED CODE: CLEAN HELPER */
/* returns 1 or 0 */
ULong amd64g_calculate_condition ( ULong/*AMD64Condcode*/ cond, 
                                   ULong cc_op, 
                                   ULong cc_dep1, 
                                   ULong cc_dep2,
                                   ULong cc_ndep )
{
   ULong rflags = amd64g_calculate_rflags_all_WRK(cc_op, cc_dep1, 
                                                  cc_dep2, cc_ndep);
   ULong of,sf,zf,cf,pf;
   ULong inv = cond & 1;

#  if PROFILE_RFLAGS
   if (!initted) initCounts();
   tab_cond[cc_op][cond]++;
   n_calc_cond++;
   if (SHOW_COUNTS_NOW) showCounts();
#  endif

   switch (cond) {
      case AMD64CondNO:
      case AMD64CondO: /* OF == 1 */
         of = rflags >> AMD64G_CC_SHIFT_O;
         return 1 & (inv ^ of);

      case AMD64CondNZ:
      case AMD64CondZ: /* ZF == 1 */
         zf = rflags >> AMD64G_CC_SHIFT_Z;
         return 1 & (inv ^ zf);

      case AMD64CondNB:
      case AMD64CondB: /* CF == 1 */
         cf = rflags >> AMD64G_CC_SHIFT_C;
         return 1 & (inv ^ cf);
         break;

      case AMD64CondNBE:
      case AMD64CondBE: /* (CF or ZF) == 1 */
         cf = rflags >> AMD64G_CC_SHIFT_C;
         zf = rflags >> AMD64G_CC_SHIFT_Z;
         return 1 & (inv ^ (cf | zf));
         break;

      case AMD64CondNS:
      case AMD64CondS: /* SF == 1 */
         sf = rflags >> AMD64G_CC_SHIFT_S;
         return 1 & (inv ^ sf);

      case AMD64CondNP:
      case AMD64CondP: /* PF == 1 */
         pf = rflags >> AMD64G_CC_SHIFT_P;
         return 1 & (inv ^ pf);

      case AMD64CondNL:
      case AMD64CondL: /* (SF xor OF) == 1 */
         sf = rflags >> AMD64G_CC_SHIFT_S;
         of = rflags >> AMD64G_CC_SHIFT_O;
         return 1 & (inv ^ (sf ^ of));
         break;

      case AMD64CondNLE:
      case AMD64CondLE: /* ((SF xor OF) or ZF)  == 1 */
         sf = rflags >> AMD64G_CC_SHIFT_S;
         of = rflags >> AMD64G_CC_SHIFT_O;
         zf = rflags >> AMD64G_CC_SHIFT_Z;
         return 1 & (inv ^ ((sf ^ of) | zf));
         break;

      default:
         /* shouldn't really make these calls from generated code */
         vex_printf("amd64g_calculate_condition"
                    "( %llu, %llu, 0x%llx, 0x%llx, 0x%llx )\n",
                    cond, cc_op, cc_dep1, cc_dep2, cc_ndep );
         vpanic("amd64g_calculate_condition");
   }
}


/* VISIBLE TO LIBVEX CLIENT */
ULong LibVEX_GuestAMD64_get_rflags ( /*IN*/VexGuestAMD64State* vex_state )
{
   ULong rflags = amd64g_calculate_rflags_all_WRK(
                     vex_state->guest_CC_OP,
                     vex_state->guest_CC_DEP1,
                     vex_state->guest_CC_DEP2,
                     vex_state->guest_CC_NDEP
                  );
   Long dflag = vex_state->guest_DFLAG;
   vassert(dflag == 1 || dflag == -1);
   if (dflag == -1)
      rflags |= (1<<10);
   if (vex_state->guest_IDFLAG == 1)
      rflags |= (1<<21);
   return rflags;
}


/*---------------------------------------------------------------*/
/*--- %rflags translation-time function specialisers.         ---*/
/*--- These help iropt specialise calls the above run-time    ---*/
/*--- %rflags functions.                                      ---*/
/*---------------------------------------------------------------*/

/* Used by the optimiser to try specialisations.  Returns an
   equivalent expression, or NULL if none. */

static Bool isU64 ( IRExpr* e, ULong n )
{
   return toBool( e->tag == Iex_Const
                  && e->Iex.Const.con->tag == Ico_U64
                  && e->Iex.Const.con->Ico.U64 == n );
}

IRExpr* guest_amd64_spechelper ( HChar* function_name,
                                 IRExpr** args )
{
#  define unop(_op,_a1) IRExpr_Unop((_op),(_a1))
#  define binop(_op,_a1,_a2) IRExpr_Binop((_op),(_a1),(_a2))
#  define mkU64(_n) IRExpr_Const(IRConst_U64(_n))
#  define mkU8(_n)  IRExpr_Const(IRConst_U8(_n))

   Int i, arity = 0;
   for (i = 0; args[i]; i++)
      arity++;
#  if 0
   vex_printf("spec request:\n");
   vex_printf("   %s  ", function_name);
   for (i = 0; i < arity; i++) {
      vex_printf("  ");
      ppIRExpr(args[i]);
   }
   vex_printf("\n");
#  endif

   /* --------- specialising "amd64g_calculate_condition" --------- */

   if (vex_streq(function_name, "amd64g_calculate_condition")) {
      /* specialise calls to above "calculate condition" function */
      IRExpr *cond, *cc_op, *cc_dep1, *cc_dep2;
      vassert(arity == 5);
      cond    = args[0];
      cc_op   = args[1];
      cc_dep1 = args[2];
      cc_dep2 = args[3];

      /*---------------- ADDQ ----------------*/

      if (isU64(cc_op, AMD64G_CC_OP_ADDQ) && isU64(cond, AMD64CondZ)) {
         /* long long add, then Z --> test (dst+src == 0) */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpEQ64, 
                           binop(Iop_Add64, cc_dep1, cc_dep2),
                           mkU64(0)));
      }

      /*---------------- SUBQ ----------------*/

      if (isU64(cc_op, AMD64G_CC_OP_SUBQ) && isU64(cond, AMD64CondZ)) {
         /* long long sub/cmp, then Z --> test dst==src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpEQ64,cc_dep1,cc_dep2));
      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBQ) && isU64(cond, AMD64CondNZ)) {
         /* long long sub/cmp, then NZ --> test dst!=src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpNE64,cc_dep1,cc_dep2));
      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBQ) && isU64(cond, AMD64CondL)) {
         /* long long sub/cmp, then L (signed less than) 
            --> test dst <s src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpLT64S, cc_dep1, cc_dep2));
      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBQ) && isU64(cond, AMD64CondB)) {
         /* long long sub/cmp, then B (unsigned less than)
            --> test dst <u src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpLT64U, cc_dep1, cc_dep2));
      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBQ) && isU64(cond, AMD64CondNB)) {
         /* long long sub/cmp, then NB (unsigned greater than or equal)
            --> test src <=u dst */
         /* Note, args are opposite way round from the usual */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpLE64U, cc_dep2, cc_dep1));
      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBQ) && isU64(cond, AMD64CondBE)) {
         /* long long sub/cmp, then BE (unsigned less than or equal)
            --> test dst <=u src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpLE64U, cc_dep1, cc_dep2));
      }

      /*---------------- SUBL ----------------*/

      if (isU64(cc_op, AMD64G_CC_OP_SUBL) && isU64(cond, AMD64CondZ)) {
         /* long sub/cmp, then Z --> test dst==src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpEQ64, 
                           binop(Iop_Shl64,cc_dep1,mkU8(32)),
                           binop(Iop_Shl64,cc_dep2,mkU8(32))));
      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBL) && isU64(cond, AMD64CondNZ)) {
         /* long sub/cmp, then NZ --> test dst!=src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpNE64, 
                           binop(Iop_Shl64,cc_dep1,mkU8(32)),
                           binop(Iop_Shl64,cc_dep2,mkU8(32))));
      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBL) && isU64(cond, AMD64CondL)) {
         /* long sub/cmp, then L (signed less than) 
            --> test dst <s src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpLT64S, 
                           binop(Iop_Shl64,cc_dep1,mkU8(32)),
                           binop(Iop_Shl64,cc_dep2,mkU8(32))));
      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBL) && isU64(cond, AMD64CondLE)) {
         /* long sub/cmp, then LE (signed less than or equal) 
            --> test dst <=s src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpLE64S, 
                           binop(Iop_Shl64,cc_dep1,mkU8(32)),
                           binop(Iop_Shl64,cc_dep2,mkU8(32))));

      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBL) && isU64(cond, AMD64CondBE)) {
         /* long sub/cmp, then BE (unsigned less than or equal)
            --> test dst <=u src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpLE64U, 
                           binop(Iop_Shl64,cc_dep1,mkU8(32)),
                           binop(Iop_Shl64,cc_dep2,mkU8(32))));
      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBL) && isU64(cond, AMD64CondNBE)) {
         /* long sub/cmp, then NBE (unsigned greater than)
            --> test src <u dst */
         /* Note, args are opposite way round from the usual */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpLT64U, 
                           binop(Iop_Shl64,cc_dep2,mkU8(32)),
                           binop(Iop_Shl64,cc_dep1,mkU8(32))));
      }

      /*---------------- SUBW ----------------*/

      if (isU64(cc_op, AMD64G_CC_OP_SUBW) && isU64(cond, AMD64CondZ)) {
         /* word sub/cmp, then Z --> test dst==src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpEQ16, 
                           unop(Iop_64to16,cc_dep1),
                           unop(Iop_64to16,cc_dep2)));
      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBW) && isU64(cond, AMD64CondLE)) {
         /* word sub/cmp, then LE (signed less than or equal) 
            --> test dst <=s src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpLE64S, 
                           binop(Iop_Shl64,cc_dep1,mkU8(48)),
                           binop(Iop_Shl64,cc_dep2,mkU8(48))));

      }

      /*---------------- SUBB ----------------*/

      if (isU64(cc_op, AMD64G_CC_OP_SUBB) && isU64(cond, AMD64CondZ)) {
         /* byte sub/cmp, then Z --> test dst==src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpEQ8, 
                           unop(Iop_64to8,cc_dep1),
                           unop(Iop_64to8,cc_dep2)));
      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBB) && isU64(cond, AMD64CondNZ)) {
         /* byte sub/cmp, then NZ --> test dst!=src */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpNE8, 
                           unop(Iop_64to8,cc_dep1),
                           unop(Iop_64to8,cc_dep2)));
      }

      if (isU64(cc_op, AMD64G_CC_OP_SUBB) && isU64(cond, AMD64CondS)
                                          && isU64(cc_dep2, 0)) {
         /* byte sub/cmp of zero, then S --> test (dst-0 <s 0)
                                         --> test dst <s 0
                                         --> (ULong)dst[7]
            This is yet another scheme by which gcc figures out if the
            top bit of a byte is 1 or 0.  See also LOGICB/CondS below. */
         /* Note: isU64(cc_dep2, 0) is correct, even though this is
            for an 8-bit comparison, since the args to the helper
            function are always U64s. */
         return binop(Iop_And64,
                      binop(Iop_Shr64,cc_dep1,mkU8(7)),
                      mkU64(1));
      }

//      if (isU64(cc_op, AMD64G_CC_OP_SUBB) && isU64(cond, AMD64CondNZ)) {
//         /* byte sub/cmp, then NZ --> test dst!=src */
//         return unop(Iop_32Uto64,
//                unop(Iop_1Uto32,
//                     binop(Iop_CmpNE8, 
//                           unop(Iop_32to8,unop(Iop_64to32,cc_dep1)),
//                           unop(Iop_32to8,unop(Iop_64to32,cc_dep2)))));
//      }

//..       if (isU32(cc_op, AMD64G_CC_OP_SUBB) && isU32(cond, X86CondNBE)) {
//..          /* long sub/cmp, then NBE (unsigned greater than)
//..             --> test src <u dst */
//..          /* Note, args are opposite way round from the usual */
//..          return unop(Iop_1Uto32,
//..                      binop(Iop_CmpLT32U, 
//..                            binop(Iop_And32,cc_dep2,mkU32(0xFF)),
//.. 			   binop(Iop_And32,cc_dep1,mkU32(0xFF))));
//..       }

      /*---------------- LOGICQ ----------------*/

      if (isU64(cc_op, AMD64G_CC_OP_LOGICQ) && isU64(cond, AMD64CondZ)) {
         /* long long and/or/xor, then Z --> test dst==0 */
         return unop(Iop_1Uto64,
                     binop(Iop_CmpEQ64, cc_dep1, mkU64(0)));
      }

      if (isU64(cc_op, AMD64G_CC_OP_LOGICQ) && isU64(cond, AMD64CondL)) {
         /* long long and/or/xor, then L