path: root/libdwarf/dwarf_loclist.c

/* Return location expression list.
   Copyright (C) 2000, 2001, 2002 Red Hat, Inc.
   This file is part of Red Hat elfutils.
   Written by Ulrich Drepper <drepper@redhat.com>, 2000.

   Red Hat elfutils is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by the
   Free Software Foundation; version 2 of the License.

   Red Hat elfutils is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License along
   with Red Hat elfutils; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.

   Red Hat elfutils is an included package of the Open Invention Network.
   An included package of the Open Invention Network is a package for which
   Open Invention Network licensees cross-license their patents.  No patent
   license is granted, either expressly or impliedly, by designation as an
   included package.  Should you wish to participate in the Open Invention
   Network licensing program, please visit www.openinventionnetwork.com
   <http://www.openinventionnetwork.com>.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <dwarf.h>
#include <stdlib.h>

#include <libdwarfP.h>


struct loclist
{
  Dwarf_Small atom;
  Dwarf_Unsigned number;
  Dwarf_Unsigned number2;
  Dwarf_Unsigned offset;
  struct loclist *next;
};

struct locdesclist
{
  Dwarf_Addr lopc;
  Dwarf_Addr hipc;
  Dwarf_Half cents;
  struct loclist *s;
  struct locdesclist *next;
};


int
dwarf_loclist (attr, llbuf, listlen, error)
     Dwarf_Attribute attr;
     Dwarf_Locdesc **llbuf;
     Dwarf_Signed *listlen;
     Dwarf_Error *error;
{
  Dwarf_CU_Info cu = attr->cu;
  Dwarf_Debug dbg = cu->dbg;
  Dwarf_Unsigned offset;
  Dwarf_Unsigned offset_end;
  Dwarf_Small *locp;
  struct locdesclist *locdesclist;
  Dwarf_Locdesc *result;
  unsigned int n;

  /* Must by one of the attribute listed below.  */
  if (attr->code != DW_AT_location
      && attr->code != DW_AT_data_member_location
      && attr->code != DW_AT_vtable_elem_location
      && attr->code != DW_AT_string_length
      && attr->code != DW_AT_use_location
      && attr->code != DW_AT_return_addr)
    {
      __libdwarf_error (dbg, error, DW_E_WRONG_ATTR);
      return DW_DLV_ERROR;
    }

  /* Must have the form data4 or data8 which act as an offset.  */
  if (attr->form == DW_FORM_data4)
    offset = read_4ubyte_unaligned (dbg, attr->valp);
  else if (likely (attr->form == DW_FORM_data8))
    offset = read_8ubyte_unaligned (dbg, attr->valp);
  else
    {
      __libdwarf_error (dbg, error, DW_E_NO_DATA);
      return DW_DLV_ERROR;
    }

  /* Check whether the .debug_loc section is available.  */
  if (unlikely (dbg->sections[IDX_debug_loc].addr == NULL))
    {
      __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
      return DW_DLV_ERROR;
    }

  /* This is the part of the .debug_loc section we can read.  */
  locp = (Dwarf_Small *) dbg->sections[IDX_debug_loc].addr + offset;
  offset_end = offset + dbg->sections[IDX_debug_loc].size;

  locdesclist = NULL;
  n = 0;
  while (1)
    {
      Dwarf_Addr lopc;
      Dwarf_Addr hipc;
      Dwarf_Ptr data;
      Dwarf_Unsigned len2;
      struct locdesclist *newdesc;
      Dwarf_Small *locp;
      Dwarf_Small *blkendp;
      Dwarf_Small *blkstartp;

      if (unlikely (dwarf_get_loclist_entry (dbg, offset, &hipc, &lopc, &data,
					     &len2, &offset, error)
		    != DW_DLV_OK))
	return DW_DLV_ERROR;

      /* Does this signal the end?  */
      if (lopc == 0 && hipc == 0)
	break;

      locp = data;
      blkstartp = locp;
      blkendp = locp + len2;

      /* Create a new Locdesc entry.  */
      newdesc = (struct locdesclist *) alloca (sizeof (struct locdesclist));
      newdesc->lopc = lopc;
      newdesc->hipc = hipc;
      newdesc->cents = 0;
      newdesc->s = NULL;
      newdesc->next = locdesclist;
      locdesclist = newdesc;
      ++n;

      /* Decode the opcodes.  It is possible in some situations to
         have a block of size zero.  */
      while (locp < blkendp)
	{
	  struct loclist *newloc;

	  newloc = (struct loclist *) alloca (sizeof (struct loclist));
	  newloc->number = 0;
	  newloc->number2 = 0;
	  newloc->offset = locp - blkstartp;
	  newloc->next = newdesc->s;
	  newdesc->s = newloc;
	  ++newdesc->cents;

	  newloc->atom = *locp;
	  switch (*locp++)
	    {
	    case DW_OP_addr:
	      /* Address, depends on address size of CU.  */
	      if (cu->address_size == 4)
		{
		  if (unlikely (locp + 4 > blkendp))
		    {
		      __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
		      return DW_DLV_ERROR;
		    }
		  newloc->number = read_4ubyte_unaligned (dbg, locp);
		  locp += 4;
		}
	      else
		{
		  if (unlikely (locp + 8 > blkendp))
		    {
		      __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
		      return DW_DLV_ERROR;
		    }
		  newloc->number = read_8ubyte_unaligned (dbg, locp);
		  locp += 8;
		}
	      break;

	    case DW_OP_deref:
	    case DW_OP_dup:
	    case DW_OP_drop:
	    case DW_OP_over:
	    case DW_OP_swap:
	    case DW_OP_rot:
	    case DW_OP_xderef:
	    case DW_OP_abs:
	    case DW_OP_and:
	    case DW_OP_div:
	    case DW_OP_minus:
	    case DW_OP_mod:
	    case DW_OP_mul:
	    case DW_OP_neg:
	    case DW_OP_not:
	    case DW_OP_or:
	    case DW_OP_plus:
	    case DW_OP_shl:
	    case DW_OP_shr:
	    case DW_OP_shra:
	    case DW_OP_xor:
	    case DW_OP_eq:
	    case DW_OP_ge:
	    case DW_OP_gt:
	    case DW_OP_le:
	    case DW_OP_lt:
	    case DW_OP_ne:
	    case DW_OP_lit0:
	    case DW_OP_lit1:
	    case DW_OP_lit2:
	    case DW_OP_lit3:
	    case DW_OP_lit4:
	    case DW_OP_lit5:
	    case DW_OP_lit6:
	    case DW_OP_lit7:
	    case DW_OP_lit8:
	    case DW_OP_lit9:
	    case DW_OP_lit10:
	    case DW_OP_lit11:
	    case DW_OP_lit12:
	    case DW_OP_lit13:
	    case DW_OP_lit14:
	    case DW_OP_lit15:
	    case DW_OP_lit16:
	    case DW_OP_lit17:
	    case DW_OP_lit18:
	    case DW_OP_lit19:
	    case DW_OP_lit20:
	    case DW_OP_lit21:
	    case DW_OP_lit22:
	    case DW_OP_lit23:
	    case DW_OP_lit24:
	    case DW_OP_lit25:
	    case DW_OP_lit26:
	    case DW_OP_lit27:
	    case DW_OP_lit28:
	    case DW_OP_lit29:
	    case DW_OP_lit30:
	    case DW_OP_lit31:
	    case DW_OP_reg0:
	    case DW_OP_reg1:
	    case DW_OP_reg2:
	    case DW_OP_reg3:
	    case DW_OP_reg4:
	    case DW_OP_reg5:
	    case DW_OP_reg6:
	    case DW_OP_reg7:
	    case DW_OP_reg8:
	    case DW_OP_reg9:
	    case DW_OP_reg10:
	    case DW_OP_reg11:
	    case DW_OP_reg12:
	    case DW_OP_reg13:
	    case DW_OP_reg14:
	    case DW_OP_reg15:
	    case DW_OP_reg16:
	    case DW_OP_reg17:
	    case DW_OP_reg18:
	    case DW_OP_reg19:
	    case DW_OP_reg20:
	    case DW_OP_reg21:
	    case DW_OP_reg22:
	    case DW_OP_reg23:
	    case DW_OP_reg24:
	    case DW_OP_reg25:
	    case DW_OP_reg26:
	    case DW_OP_reg27:
	    case DW_OP_reg28:
	    case DW_OP_reg29:
	    case DW_OP_reg30:
	    case DW_OP_reg31:
	    case DW_OP_nop:
	    case DW_OP_push_object_address:
	    case DW_OP_call_ref:
	      /* No operand.  */
	      break;

	    case DW_OP_const1u:
	    case DW_OP_pick:
	    case DW_OP_deref_size:
	    case DW_OP_xderef_size:
	      if (unlikely (locp >= blkendp))
		{
		  __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
		  return DW_DLV_ERROR;
		}
	      newloc->number = *((uint8_t *) locp)++;
	      break;

	    case DW_OP_const1s:
	      if (unlikely (locp >= blkendp))
		{
		  __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
		  return DW_DLV_ERROR;
		}
	      newloc->number = *((int8_t *) locp)++;
	      break;

	    case DW_OP_const2u:
	      if (unlikely (locp + 2 > blkendp))
		{
		  __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
		  return DW_DLV_ERROR;
		}
	      newloc->number = read_2ubyte_unaligned (dbg, locp);
	      locp += 2;
	      break;

	    case DW_OP_const2s:
	    case DW_OP_skip:
	    case DW_OP_bra:
	    case DW_OP_call2:
	      if (unlikely (locp + 2 > blkendp))
		{
		  __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
		  return DW_DLV_ERROR;
		}
	      newloc->number = read_2sbyte_unaligned (dbg, locp);
	      locp += 2;
	      break;

	    case DW_OP_const4u:
	      if (unlikely (locp + 4 > blkendp))
		{
		  __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
		  return DW_DLV_ERROR;
		}
	      newloc->number = read_4ubyte_unaligned (dbg, locp);
	      locp += 4;
	      break;

	    case DW_OP_const4s:
	    case DW_OP_call4:
	      if (unlikely (locp + 4 > blkendp))
		{
		  __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
		  return DW_DLV_ERROR;
		}
	      newloc->number = read_4sbyte_unaligned (dbg, locp);
	      locp += 4;
	      break;

	    case DW_OP_const8u:
	      if (unlikely (locp + 8 > blkendp))
		{
		  __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
		  return DW_DLV_ERROR;
		}
	      newloc->number = read_8ubyte_unaligned (dbg, locp);
	      locp += 8;
	      break;

	    case DW_OP_const8s:
	      if (unlikely (locp + 8 > blkendp))
		{
		  __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
		  return DW_DLV_ERROR;
		}
	      newloc->number = read_8sbyte_unaligned (dbg, locp);
	      locp += 8;
	      break;

	    case DW_OP_constu:
	    case DW_OP_plus_uconst:
	    case DW_OP_regx:
	    case DW_OP_piece:
	      /* XXX Check size.  */
	      get_uleb128 (newloc->number, locp);
	      break;

	    case DW_OP_consts:
	    case DW_OP_breg0:
	    case DW_OP_breg1:
	    case DW_OP_breg2:
	    case DW_OP_breg3:
	    case DW_OP_breg4:
	    case DW_OP_breg5:
	    case DW_OP_breg6:
	    case DW_OP_breg7:
	    case DW_OP_breg8:
	    case DW_OP_breg9:
	    case DW_OP_breg10:
	    case DW_OP_breg11:
	    case DW_OP_breg12:
	    case DW_OP_breg13:
	    case DW_OP_breg14:
	    case DW_OP_breg15:
	    case DW_OP_breg16:
	    case DW_OP_breg17:
	    case DW_OP_breg18:
	    case DW_OP_breg19:
	    case DW_OP_breg20:
	    case DW_OP_breg21:
	    case DW_OP_breg22:
	    case DW_OP_breg23:
	    case DW_OP_breg24:
	    case DW_OP_breg25:
	    case DW_OP_breg26:
	    case DW_OP_breg27:
	    case DW_OP_breg28:
	    case DW_OP_breg29:
	    case DW_OP_breg30:
	    case DW_OP_breg31:
	    case DW_OP_fbreg:
	      /* XXX Check size.  */
	      get_sleb128 (newloc->number, locp);
	      break;

	    case DW_OP_bregx:
	      /* XXX Check size.  */
	      get_uleb128 (newloc->number, locp);
	      get_sleb128 (newloc->number2, locp);
	      break;

	    default:
	      __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
	      return DW_DLV_ERROR;
	    }
	}
    }

  if (unlikely (n == 0))
    {
      /* This is not allowed.

	 XXX Is it?  */
      __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
      return DW_DLV_ERROR;
    }

  /* Allocate the array.  */
  result = (Dwarf_Locdesc *) malloc (n * sizeof (Dwarf_Locdesc));
  if (result == NULL)
    {
      __libdwarf_error (dbg, error, DW_E_NOMEM);
      return DW_DLV_ERROR;
    }

  /* Store the result.  */
  *llbuf = result;
  *listlen = n;

  do
    {
      unsigned int cents;
      struct loclist *s;

      /* We populate the array from the back since the list is
         backwards.  */
      --n;

      result[n].ld_lopc = locdesclist->lopc;
      result[n].ld_hipc = locdesclist->hipc;
      result[n].ld_cents = cents = locdesclist->cents;
      result[n].ld_s = (Dwarf_Loc *) malloc (cents * sizeof (Dwarf_Loc));
      if (result == NULL)
	{
	  /* XXX Should be bother freeing memory?  */
	  __libdwarf_error (dbg, error, DW_E_NOMEM);
	  return DW_DLV_ERROR;
	}

      s = locdesclist->s;
      while (cents-- > 0)
	{
	  /* This list is also backwards.  */
	  result[n].ld_s[cents].lr_atom = s->atom;
	  result[n].ld_s[cents].lr_number = s->number;
	  result[n].ld_s[cents].lr_number2 = s->number2;
	  result[n].ld_s[cents].lr_offset = s->offset;
	  s = s->next;
	}

      locdesclist = locdesclist->next;
    }
  while (n > 0);

  /* We did it.  */
  return DW_DLV_OK;
}