ghelpers.c

unix下调试内存泄露的工具源代码

   }
   vex_printf("\n");
#  endif

   /* --------- specialising "x86g_calculate_condition" --------- */

   if (vex_streq(function_name, "x86g_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];

      /*---------------- ADDL ----------------*/

      if (isU32(cc_op, X86G_CC_OP_ADDL) && isU32(cond, X86CondZ)) {
         /* long add, then Z --> test (dst+src == 0) */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpEQ32, 
                           binop(Iop_Add32, cc_dep1, cc_dep2),
                           mkU32(0)));
      }

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

      if (isU32(cc_op, X86G_CC_OP_SUBL) && isU32(cond, X86CondZ)) {
         /* long sub/cmp, then Z --> test dst==src */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpEQ32, cc_dep1, cc_dep2));
      }

      if (isU32(cc_op, X86G_CC_OP_SUBL) && isU32(cond, X86CondNZ)) {
         /* long sub/cmp, then NZ --> test dst!=src */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpNE32, cc_dep1, cc_dep2));
      }

      if (isU32(cc_op, X86G_CC_OP_SUBL) && isU32(cond, X86CondL)) {
         /* long sub/cmp, then L (signed less than) 
            --> test dst <s src */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpLT32S, cc_dep1, cc_dep2));
      }

      if (isU32(cc_op, X86G_CC_OP_SUBL) && isU32(cond, X86CondLE)) {
         /* long sub/cmp, then LE (signed less than or equal)
            --> test dst <=s src */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpLE32S, cc_dep1, cc_dep2));
      }

      if (isU32(cc_op, X86G_CC_OP_SUBL) && isU32(cond, X86CondBE)) {
         /* long sub/cmp, then BE (unsigned less than or equal)
            --> test dst <=u src */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpLE32U, cc_dep1, cc_dep2));
      }

      if (isU32(cc_op, X86G_CC_OP_SUBL) && isU32(cond, X86CondB)) {
         /* long sub/cmp, then B (unsigned less than)
            --> test dst <u src */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpLT32U, cc_dep1, cc_dep2));
      }

      if (isU32(cc_op, X86G_CC_OP_SUBL) && isU32(cond, X86CondS)) {
         /* long sub/cmp, then S --> test (dst-src <s 0) */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpLT32S, 
                           binop(Iop_Sub32, cc_dep1, cc_dep2),
                           mkU32(0)));
      }

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

      if (isU32(cc_op, X86G_CC_OP_SUBW) && isU32(cond, X86CondZ)) {
         /* byte sub/cmp, then Z --> test dst==src */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpEQ16, 
                           unop(Iop_32to16,cc_dep1), 
                           unop(Iop_32to16,cc_dep2)));
      }

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

      if (isU32(cc_op, X86G_CC_OP_SUBB) && isU32(cond, X86CondZ)) {
         /* byte sub/cmp, then Z --> test dst==src */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpEQ8, 
                           unop(Iop_32to8,cc_dep1), 
                           unop(Iop_32to8,cc_dep2)));
      }

      if (isU32(cc_op, X86G_CC_OP_SUBB) && isU32(cond, X86CondNZ)) {
         /* byte sub/cmp, then NZ --> test dst!=src */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpNE8, 
                           unop(Iop_32to8,cc_dep1), 
                           unop(Iop_32to8,cc_dep2)));
      }

      if (isU32(cc_op, X86G_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))));
      }

      /*---------------- LOGICL ----------------*/

      if (isU32(cc_op, X86G_CC_OP_LOGICL) && isU32(cond, X86CondZ)) {
         /* long and/or/xor, then Z --> test dst==0 */
         return unop(Iop_1Uto32,binop(Iop_CmpEQ32, cc_dep1, mkU32(0)));
      }

      if (isU32(cc_op, X86G_CC_OP_LOGICL) && isU32(cond, X86CondS)) {
         /* long and/or/xor, then S --> test dst <s 0 */
         return unop(Iop_1Uto32,binop(Iop_CmpLT32S, cc_dep1, mkU32(0)));
      }

      if (isU32(cc_op, X86G_CC_OP_LOGICL) && isU32(cond, X86CondLE)) {
         /* long and/or/xor, then LE
            This is pretty subtle.  LOGIC sets SF and ZF according to the
            result and makes OF be zero.  LE computes (SZ ^ OF) | ZF, but
            OF is zero, so this reduces to SZ | ZF -- which will be 1 iff
            the result is <=signed 0.  Hence ...
         */
         return unop(Iop_1Uto32,binop(Iop_CmpLE32S, cc_dep1, mkU32(0)));
      }

      if (isU32(cc_op, X86G_CC_OP_LOGICL) && isU32(cond, X86CondBE)) {
         /* long and/or/xor, then BE
            LOGIC sets ZF according to the result and makes CF be zero.
            BE computes (CF | ZF), but CF is zero, so this reduces ZF 
            -- which will be 1 iff the result is zero.  Hence ...
         */
         return unop(Iop_1Uto32,binop(Iop_CmpEQ32, cc_dep1, mkU32(0)));
      }

      /*---------------- LOGICW ----------------*/

      if (isU32(cc_op, X86G_CC_OP_LOGICW) && isU32(cond, X86CondZ)) {
         /* byte and/or/xor, then Z --> test dst==0 */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpEQ32, binop(Iop_And32,cc_dep1,mkU32(0xFFFF)), 
                                        mkU32(0)));
      }

      /*---------------- LOGICB ----------------*/

      if (isU32(cc_op, X86G_CC_OP_LOGICB) && isU32(cond, X86CondZ)) {
         /* byte and/or/xor, then Z --> test dst==0 */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpEQ32, binop(Iop_And32,cc_dep1,mkU32(255)), 
                                        mkU32(0)));
      }

      /*---------------- DECL ----------------*/

      if (isU32(cc_op, X86G_CC_OP_DECL) && isU32(cond, X86CondZ)) {
         /* dec L, then Z --> test dst == 0 */
         return unop(Iop_1Uto32,binop(Iop_CmpEQ32, cc_dep1, mkU32(0)));
      }

      if (isU32(cc_op, X86G_CC_OP_DECL) && isU32(cond, X86CondS)) {
         /* dec L, then S --> compare DST <s 0 */
         return unop(Iop_1Uto32,binop(Iop_CmpLT32S, cc_dep1, mkU32(0)));
      }

      /*---------------- SHRL ----------------*/

      if (isU32(cc_op, X86G_CC_OP_SHRL) && isU32(cond, X86CondZ)) {
         /* SHRL, then Z --> test dep1 == 0 */
         return unop(Iop_1Uto32,binop(Iop_CmpEQ32, cc_dep1, mkU32(0)));
      }

      /*---------------- COPY ----------------*/
      /* This can happen, as a result of x87 FP compares: "fcom ... ;
         fnstsw %ax ; sahf ; jbe" for example. */

      if (isU32(cc_op, X86G_CC_OP_COPY) && 
          (isU32(cond, X86CondBE) || isU32(cond, X86CondNBE))) {
         /* COPY, then BE --> extract C and Z from dep1, and test (C
            or Z == 1). */
         /* COPY, then NBE --> extract C and Z from dep1, and test (C
            or Z == 0). */
         UInt nnn = isU32(cond, X86CondBE) ? 1 : 0;
         return
            unop(
               Iop_1Uto32,
               binop(
                  Iop_CmpEQ32,
                  binop(
                     Iop_And32,
                     binop(
                        Iop_Or32,
                        binop(Iop_Shr32, cc_dep1, mkU8(X86G_CC_SHIFT_C)),
                        binop(Iop_Shr32, cc_dep1, mkU8(X86G_CC_SHIFT_Z))
                     ),
                     mkU32(1)
                  ),
                  mkU32(nnn)
               )
            );
      }
      
      if (isU32(cc_op, X86G_CC_OP_COPY) && 
          (isU32(cond, X86CondB) || isU32(cond, X86CondNB))) {
         /* COPY, then B --> extract C from dep1, and test (C == 1). */
         /* COPY, then NB --> extract C from dep1, and test (C == 0). */
         UInt nnn = isU32(cond, X86CondB) ? 1 : 0;
         return
            unop(
               Iop_1Uto32,
               binop(
                  Iop_CmpEQ32,
                  binop(
                     Iop_And32,
                     binop(Iop_Shr32, cc_dep1, mkU8(X86G_CC_SHIFT_C)),
                     mkU32(1)
                  ),
                  mkU32(nnn)
               )
            );
      }

      if (isU32(cc_op, X86G_CC_OP_COPY) && isU32(cond, X86CondZ)) {
         /* COPY, then Z --> extract Z from dep1, and test (Z == 1). */
         return
            unop(
               Iop_1Uto32,
               binop(
                  Iop_CmpNE32,
                  binop(
                     Iop_And32,
                     binop(Iop_Shr32, cc_dep1, mkU8(X86G_CC_SHIFT_Z)),
                     mkU32(1)
                  ),
                  mkU32(0)
               )
            );
      }

      return NULL;
   }

   /* --------- specialising "x86g_calculate_eflags_c" --------- */

   if (vex_streq(function_name, "x86g_calculate_eflags_c")) {
      /* specialise calls to above "calculate_eflags_c" function */
      IRExpr *cc_op, *cc_dep1, *cc_dep2, *cc_ndep;
      vassert(arity == 4);
      cc_op   = args[0];
      cc_dep1 = args[1];
      cc_dep2 = args[2];
      cc_ndep = args[3];

      if (isU32(cc_op, X86G_CC_OP_SUBL)) {
         /* C after sub denotes unsigned less than */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpLT32U, cc_dep1, cc_dep2));
      }
      if (isU32(cc_op, X86G_CC_OP_SUBB)) {
         /* C after sub denotes unsigned less than */
         return unop(Iop_1Uto32,
                     binop(Iop_CmpLT32U, 
                           binop(Iop_And32,cc_dep1,mkU32(0xFF)),
                           binop(Iop_And32,cc_dep2,mkU32(0xFF))));
      }
      if (isU32(cc_op, X86G_CC_OP_LOGICL)
          || isU32(cc_op, X86G_CC_OP_LOGICW)
          || isU32(cc_op, X86G_CC_OP_LOGICB)) {
         /* cflag after logic is zero */
         return mkU32(0);
      }
      if (isU32(cc_op, X86G_CC_OP_DECL) || isU32(cc_op, X86G_CC_OP_INCL)) {
         /* If the thunk is dec or inc, the cflag is supplied as CC_NDEP. */
         return cc_ndep;
      }
      if (isU32(cc_op, X86G_CC_OP_COPY)) {
         /* cflag after COPY is stored in DEP1. */
         return
            binop(
               Iop_And32,
               binop(Iop_Shr32, cc_dep1, mkU8(X86G_CC_SHIFT_C)),
               mkU32(1)
            );
      }
#     if 0
      if (cc_op->tag == Iex_Const) {
         vex_printf("CFLAG "); ppIRExpr(cc_op); vex_printf("\n");
      }
#     endif

      return NULL;
   }

   /* --------- specialising "x86g_calculate_eflags_all" --------- */

   if (vex_streq(function_name, "x86g_calculate_eflags_all")) {
      /* specialise calls to above "calculate_eflags_all" function */
      IRExpr *cc_op, *cc_dep1; /*, *cc_dep2, *cc_ndep; */
      vassert(arity == 4);
      cc_op   = args[0];
      cc_dep1 = args[1];
      /* cc_dep2 = args[2]; */
      /* cc_ndep = args[3]; */

      if (isU32(cc_op, X86G_CC_OP_COPY)) {
         /* eflags after COPY are stored in DEP1. */
         return
            binop(
               Iop_And32,
               cc_dep1,
               mkU32(X86G_CC_MASK_O | X86G_CC_MASK_S | X86G_CC_MASK_Z 
                     | X86G_CC_MASK_A | X86G_CC_MASK_C | X86G_CC_MASK_P)
            );
      }
      return NULL;
   }

#  undef unop
#  undef binop
#  undef mkU32
#  undef mkU8

   return NULL;
}


/*---------------------------------------------------------------*/
/*--- Supporting functions for x87 FPU activities.            ---*/
/*---------------------------------------------------------------*/

static inline Bool host_is_little_endian ( void )
{
   UInt x = 0x76543210;
   UChar* p = (UChar*)(&x);
   return toBool(*p == 0x10);
}

/* 80 and 64-bit floating point formats:

   80-bit:

    S  0       0-------0      zero
    S  0       0X------X      denormals
    S  1-7FFE  1X------X      normals (all normals have leading 1)
    S  7FFF    10------0      infinity
    S  7FFF    10X-----X      snan
    S  7FFF    11X-----X      qnan

   S is the sign bit.  For runs X----X, at least one of the Xs must be
   nonzero.  Exponent is 15 bits, fractional part is 63 bits, and
   there is an explicitly represented leading 1, and a sign bit,
   giving 80 in total.

   64-bit avoids the confusion of an explicitly represented leading 1
   and so is simpler:

    S  0      0------0   zero
    S  0      X------X   denormals
    S  1-7FE  any        normals
    S  7FF    0------0   infinity
    S  7FF    0X-----X   snan
    S  7FF    1X-----X   qnan

   Exponent is 11 bits, fractional part is 52 bits, and there is a 
   sign bit, giving 64 in total.
*/

/* Inspect a value and its tag, as per the x87 'FXAM' instruction. */
/* CALLED FROM GENERATED CODE: CLEAN HELPER */
UInt x86g_calculate_FXAM ( UInt tag, ULong dbl ) 
{
   Bool   mantissaIsZero;
   Int    bexp;
   UChar  sign;
   UChar* f64;

   vassert(host_is_little_endian());

   /* vex_printf("calculate_FXAM ( %d, %llx ) .. ", tag, dbl ); */