ldexp.c

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/* This module handles expression trees.
   Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
   2001
   Free Software Foundation, Inc.
   Written by Steve Chamberlain of Cygnus Support <[e-mail]>.

This file is part of GLD, the Gnu Linker.

GLD 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; either version 2, or (at your option)
any later version.

GLD 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 GLD; see the file COPYING.  If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.  */

/* This module is in charge of working out the contents of expressions.

   It has to keep track of the relative/absness of a symbol etc. This
   is done by keeping all values in a struct (an etree_value_type)
   which contains a value, a section to which it is relative and a
   valid bit.  */

#include "bfd.h"
#include "sysdep.h"
#include "bfdlink.h"

#include "ld.h"
#include "ldmain.h"
#include "ldmisc.h"
#include "ldexp.h"
#include "ldgram.h"
#include "ldlang.h"

static void exp_print_token PARAMS ((token_code_type code));
static void make_abs PARAMS ((etree_value_type *ptr));
static etree_value_type new_abs PARAMS ((bfd_vma value));
static void check PARAMS ((lang_output_section_statement_type *os,
			   const char *name, const char *op));
static etree_value_type new_rel
  PARAMS ((bfd_vma value, lang_output_section_statement_type *section));
static etree_value_type new_rel_from_section
  PARAMS ((bfd_vma value, lang_output_section_statement_type *section));
static etree_value_type fold_binary
  PARAMS ((etree_type *tree,
	   lang_output_section_statement_type *current_section,
	   lang_phase_type allocation_done,
	   bfd_vma dot, bfd_vma *dotp));
static etree_value_type fold_name
  PARAMS ((etree_type *tree,
	   lang_output_section_statement_type *current_section,
	   lang_phase_type allocation_done,
	   bfd_vma dot));
static etree_value_type exp_fold_tree_no_dot
  PARAMS ((etree_type *tree,
	   lang_output_section_statement_type *current_section,
	   lang_phase_type allocation_done));

static void
exp_print_token (code)
     token_code_type code;
{
  static CONST struct {
    token_code_type code;
    char *name;
  } table[] = {
    { INT, "int" },
    { REL, "relocateable" },
    { NAME, "NAME" },
    { PLUSEQ, "+=" },
    { MINUSEQ, "-=" },
    { MULTEQ, "*=" },
    { DIVEQ, "/=" },
    { LSHIFTEQ, "<<=" },
    { RSHIFTEQ, ">>=" },
    { ANDEQ, "&=" },
    { OREQ, "|=" },
    { OROR, "||" },
    { ANDAND, "&&" },
    { EQ, "==" },
    { NE, "!=" },
    { LE, "<=" },
    { GE, ">=" },
    { LSHIFT, "<<" },
    { RSHIFT, ">>=" },
    { ALIGN_K, "ALIGN" },
    { BLOCK, "BLOCK" },
    { SECTIONS, "SECTIONS" },
    { SIZEOF_HEADERS, "SIZEOF_HEADERS" },
    { NEXT, "NEXT" },
    { SIZEOF, "SIZEOF" },
    { ADDR, "ADDR" },
    { LOADADDR, "LOADADDR" },
    { MEMORY, "MEMORY" },
    { DEFINED, "DEFINED" },
    { TARGET_K, "TARGET" },
    { SEARCH_DIR, "SEARCH_DIR" },
    { MAP, "MAP" },
    { QUAD, "QUAD" },
    { SQUAD, "SQUAD" },
    { LONG, "LONG" },
    { SHORT, "SHORT" },
    { BYTE, "BYTE" },
    { ENTRY, "ENTRY" },
    { 0, (char *) NULL }
  };
  unsigned int idx;

  for (idx = 0; table[idx].name != (char *) NULL; idx++)
    {
      if (table[idx].code == code)
	{
	  fprintf (config.map_file, "%s", table[idx].name);
	  return;
	}
    }
  /* Not in table, just print it alone */
  fprintf (config.map_file, "%c", code);
}

static void
make_abs (ptr)
     etree_value_type *ptr;
{
  asection *s = ptr->section->bfd_section;
  ptr->value += s->vma;
  ptr->section = abs_output_section;
}

static etree_value_type
new_abs (value)
     bfd_vma value;
{
  etree_value_type new;
  new.valid_p = true;
  new.section = abs_output_section;
  new.value = value;
  return new;
}

static void
check (os, name, op)
     lang_output_section_statement_type *os;
     const char *name;
     const char *op;
{
  if (os == NULL)
    einfo (_("%F%P: %s uses undefined section %s\n"), op, name);
  if (! os->processed)
    einfo (_("%F%P: %s forward reference of section %s\n"), op, name);
}

etree_type *
exp_intop (value)
     bfd_vma value;
{
  etree_type *new = (etree_type *) stat_alloc (sizeof (new->value));
  new->type.node_code = INT;
  new->value.value = value;
  new->type.node_class = etree_value;
  return new;

}

/* Build an expression representing an unnamed relocateable value.  */

etree_type *
exp_relop (section, value)
     asection *section;
     bfd_vma value;
{
  etree_type *new = (etree_type *) stat_alloc (sizeof (new->rel));
  new->type.node_code = REL;
  new->type.node_class = etree_rel;
  new->rel.section = section;
  new->rel.value = value;
  return new;
}

static etree_value_type
new_rel (value, section)
     bfd_vma value;
     lang_output_section_statement_type *section;
{
  etree_value_type new;
  new.valid_p = true;
  new.value = value;
  new.section = section;
  return new;
}

static etree_value_type
new_rel_from_section (value, section)
     bfd_vma value;
     lang_output_section_statement_type *section;
{
  etree_value_type new;
  new.valid_p = true;
  new.value = value;
  new.section = section;

  new.value -= section->bfd_section->vma;

  return new;
}

static etree_value_type
fold_binary (tree, current_section, allocation_done, dot, dotp)
     etree_type *tree;
     lang_output_section_statement_type *current_section;
     lang_phase_type allocation_done;
     bfd_vma dot;
     bfd_vma *dotp;
{
  etree_value_type result;

  result = exp_fold_tree (tree->binary.lhs, current_section,
			  allocation_done, dot, dotp);
  if (result.valid_p)
    {
      etree_value_type other;

      other = exp_fold_tree (tree->binary.rhs,
			     current_section,
			     allocation_done, dot, dotp);
      if (other.valid_p)
	{
	  /* If the values are from different sections, or this is an
	     absolute expression, make both the source arguments
	     absolute.  However, adding or subtracting an absolute
	     value from a relative value is meaningful, and is an
	     exception.  */
	  if (current_section != abs_output_section
	      && (other.section == abs_output_section
		  || (result.section == abs_output_section
		      && tree->type.node_code == '+'))
	      && (tree->type.node_code == '+'
		  || tree->type.node_code == '-'))
	    {
	      etree_value_type hold;

	      /* If there is only one absolute term, make sure it is the
		 second one.  */
	      if (other.section != abs_output_section)
		{
		  hold = result;
		  result = other;
		  other = hold;
		}
	    }
	  else if (result.section != other.section
		   || current_section == abs_output_section)
	    {
	      make_abs (&result);
	      make_abs (&other);
	    }

	  switch (tree->type.node_code)
	    {
	    case '%':
	      if (other.value == 0)
		einfo (_("%F%S %% by zero\n"));
	      result.value = ((bfd_signed_vma) result.value
			      % (bfd_signed_vma) other.value);
	      break;

	    case '/':
	      if (other.value == 0)
		einfo (_("%F%S / by zero\n"));
	      result.value = ((bfd_signed_vma) result.value
			      / (bfd_signed_vma) other.value);
	      break;

#define BOP(x,y) case x : result.value = result.value y other.value; break;
	      BOP ('+', +);
	      BOP ('*', *);
	      BOP ('-', -);
	      BOP (LSHIFT, <<);
	      BOP (RSHIFT, >>);
	      BOP (EQ, ==);
	      BOP (NE, !=);
	      BOP ('<', <);
	      BOP ('>', >);
	      BOP (LE, <=);
	      BOP (GE, >=);
	      BOP ('&', &);
	      BOP ('^', ^);
	      BOP ('|', |);
	      BOP (ANDAND, &&);
	      BOP (OROR, ||);

	    case MAX_K:
	      if (result.value < other.value)
		result = other;
	      break;

	    case MIN_K:
	      if (result.value > other.value)
		result = other;
	      break;

	    default:
	      FAIL ();
	    }
	}
      else
	{
	  result.valid_p = false;
	}
    }

  return result;
}

etree_value_type
invalid ()
{
  etree_value_type new;
  new.valid_p = false;
  return new;
}

static etree_value_type
fold_name (tree, current_section, allocation_done, dot)
     etree_type *tree;
     lang_output_section_statement_type *current_section;
     lang_phase_type allocation_done;
     bfd_vma dot;
{
  etree_value_type result;
  switch (tree->type.node_code)
    {
    case SIZEOF_HEADERS:
      if (allocation_done != lang_first_phase_enum)
	{
	  result = new_abs ((bfd_vma)
			    bfd_sizeof_headers (output_bfd,
						link_info.relocateable));
	}
      else
	{
	  result.valid_p = false;
	}
      break;
    case DEFINED:
      if (allocation_done == lang_first_phase_enum)
	result.valid_p = false;
      else
	{
	  struct bfd_link_hash_entry *h;

	  h = bfd_wrapped_link_hash_lookup (output_bfd, &link_info,
					    tree->name.name,
					    false, false, true);
	  result.value = (h != (struct bfd_link_hash_entry *) NULL
			  && (h->type == bfd_link_hash_defined
			      || h->type == bfd_link_hash_defweak
			      || h->type == bfd_link_hash_common));
	  result.section = 0;
	  result.valid_p = true;
	}
      break;
    case NAME:
      result.valid_p = false;
      if (tree->name.name[0] == '.' && tree->name.name[1] == 0)
	{
	  if (allocation_done != lang_first_phase_enum)
	    result = new_rel_from_section (dot, current_section);
	  else
	    result = invalid ();
	}
      else if (allocation_done != lang_first_phase_enum)
	{
	  struct bfd_link_hash_entry *h;

	  h = bfd_wrapped_link_hash_lookup (output_bfd, &link_info,
					    tree->name.name,
					    false, false, true);
	  if (h != NULL
	      && (h->type == bfd_link_hash_defined
		  || h->type == bfd_link_hash_defweak))
	    {
	      if (bfd_is_abs_section (h->u.def.section))
		result = new_abs (h->u.def.value);
	      else if (allocation_done == lang_final_phase_enum
		       || allocation_done == lang_allocating_phase_enum)
		{
		  asection *output_section;

		  output_section = h->u.def.section->output_section;
		  if (output_section == NULL)
		    einfo (_("%X%S: unresolvable symbol `%s' referenced in expression\n"),
			   tree->name.name);
		  else
		    {
		      lang_output_section_statement_type *os;

		      os = (lang_output_section_statement_lookup
			    (bfd_get_section_name (output_bfd,
						   output_section)));

		      /* FIXME: Is this correct if this section is
			 being linked with -R?  */
		      result = new_rel ((h->u.def.value
					 + h->u.def.section->output_offset),
					os);
		    }
		}
	    }
	  else if (allocation_done == lang_final_phase_enum)
	    einfo (_("%F%S: undefined symbol `%s' referenced in expression\n"),
		   tree->name.name);
	}
      break;

    case ADDR:
      if (allocation_done != lang_first_phase_enum)
	{
	  lang_output_section_statement_type *os;

	  os = lang_output_section_find (tree->name.name);
	  check (os, tree->name.name, "ADDR");
	  result = new_rel (0, os);
	}
      else
	result = invalid ();
      break;

    case LOADADDR:
      if (allocation_done != lang_first_phase_enum)
	{
	  lang_output_section_statement_type *os;

	  os = lang_output_section_find (tree->name.name);
	  check (os, tree->name.name, "LOADADDR");
	  if (os->load_base == NULL)
	    result = new_rel (0, os);
	  else
	    result = exp_fold_tree_no_dot (os->load_base,
					   abs_output_section,
					   allocation_done);
	}
      else
	result = invalid ();
      break;

    case SIZEOF:
      if (allocation_done != lang_first_phase_enum)
	{
	  int opb = bfd_octets_per_byte (output_bfd);
	  lang_output_section_statement_type *os;

	  os = lang_output_section_find (tree->name.name);
	  check (os, tree->name.name, "SIZEOF");
	  result = new_abs (os->bfd_section->_raw_size / opb);
	}
      else
	result = invalid ();
      break;

    default:
      FAIL ();
      break;
    }

  return result;
}

etree_value_type
exp_fold_tree (tree, current_section, allocation_done, dot, dotp)
     etree_type *tree;
     lang_output_section_statement_type *current_section;
     lang_phase_type allocation_done;
     bfd_vma dot;
     bfd_vma *dotp;
{
  etree_value_type result;

  if (tree == NULL)
    {
      result.valid_p = false;
      return result;
    }

  switch (tree->type.node_class)
    {
    case etree_value:
      result = new_rel (tree->value.value, current_section);
      break;