VEX/priv/ir_match.c

   1
   2 /*---------------------------------------------------------------*/
   3 /*--- begin                                        ir_match.c ---*/
   4 /*---------------------------------------------------------------*/
   5
   6 /*
   7    This file is part of Valgrind, a dynamic binary instrumentation
   8    framework.
   9
  10    Copyright (C) 2004-2017 OpenWorks LLP
  11       info@open-works.net
  12
  13    This program is free software; you can redistribute it and/or
  14    modify it under the terms of the GNU General Public License as
  15    published by the Free Software Foundation; either version 2 of the
  16    License, or (at your option) any later version.
  17
  18    This program is distributed in the hope that it will be useful, but
  19    WITHOUT ANY WARRANTY; without even the implied warranty of
  20    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  21    General Public License for more details.
  22
  23    You should have received a copy of the GNU General Public License
  24    along with this program; if not, write to the Free Software
  25    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  26    02110-1301, USA.
  27
  28    The GNU General Public License is contained in the file COPYING.
  29
  30    Neither the names of the U.S. Department of Energy nor the
  31    University of California nor the names of its contributors may be
  32    used to endorse or promote products derived from this software
  33    without prior written permission.
  34 */
  35
  36 /* Provides a facility for doing IR tree matching. */
  37
  38 #include "main_util.h"
  39 #include "ir_match.h"
  40
  41
  42 /* Assign a value to a binder.  Checks for obvious stupidities. */
  43
  44 static
  45 void setBindee ( MatchInfo* mi, Int n, const IRExpr* bindee )
  46 {
  47    if (n < 0 || n >= N_IRMATCH_BINDERS)
  48       vpanic("setBindee: out of range index");
  49    if (mi->bindee[n] != NULL)
  50       vpanic("setBindee: bindee already set");
  51    mi->bindee[n] = bindee;
  52 }
  53
  54
  55 /* This is the actual matching function, recursing over the pattern
  56    and expression trees in the obvious way, and dumping any matches
  57    found into 'mi'. */
  58
  59 static
  60 Bool matchWrk ( MatchInfo* mi, const IRExpr* p/*attern*/,
  61                 const IRExpr* e/*xpr*/ )
  62 {
  63    switch (p->tag) {
  64       case Iex_Binder: /* aha, what we were looking for. */
  65          setBindee(mi, p->Iex.Binder.binder, e);
  66          return True;
  67       case Iex_Unop:
  68          if (e->tag != Iex_Unop) return False;
  69          if (p->Iex.Unop.op != e->Iex.Unop.op) return False;
  70          if (!matchWrk(mi, p->Iex.Unop.arg, e->Iex.Unop.arg))
  71             return False;
  72          return True;
  73       case Iex_Binop:
  74          if (e->tag != Iex_Binop) return False;
  75          if (p->Iex.Binop.op != e->Iex.Binop.op) return False;
  76          if (!matchWrk(mi, p->Iex.Binop.arg1, e->Iex.Binop.arg1))
  77             return False;
  78          if (!matchWrk(mi, p->Iex.Binop.arg2, e->Iex.Binop.arg2))
  79             return False;
  80          return True;
  81       case Iex_Load:
  82          if (e->tag != Iex_Load) return False;
  83          if (p->Iex.Load.end != e->Iex.Load.end) return False;
  84          if (p->Iex.Load.ty != e->Iex.Load.ty) return False;
  85          if (!matchWrk(mi, p->Iex.Load.addr, e->Iex.Load.addr))
  86             return False;
  87          return True;
  88       case Iex_Const:
  89          if (e->tag != Iex_Const) return False;
  90          return eqIRConst(p->Iex.Const.con, e->Iex.Const.con);
  91       default:
  92          ppIRExpr(p);
  93          vpanic("match");
  94    }
  95 }
  96
  97
  98 /* Top level entry point to the matcher. */
  99
 100 Bool matchIRExpr ( MatchInfo* mi, const IRExpr* p/*attern*/,
 101                    const IRExpr* e/*xpr*/ )
 102 {
 103    Int i;
 104    for (i = 0; i < N_IRMATCH_BINDERS; i++)
 105       mi->bindee[i] = NULL;
 106    return matchWrk(mi, p, e);
 107 }
 108
 109
 110
 111 /*---------------------------------------------------------------*/
 112 /*--- end                                          ir_match.c ---*/
 113 /*---------------------------------------------------------------*/