binutils-gdb/ld/ldexp.c

/* This module handles expression trees.
Copyright (C) 1991, 1993, 1994, 1995 Free Software Foundation, Inc.
Written by Steve Chamberlain of Cygnus Support (sac@cygnus.com).

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, 675 Mass Ave, Cambridge, MA 02139, 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" },
	{ MEMORY,"MEMORY" },
	{ DEFINED,"DEFINED" },
	{ TARGET_K,"TARGET" },
	{ SEARCH_DIR,"SEARCH_DIR" },
	{ MAP,"MAP" },
	{ QUAD,"QUAD" },
	{ 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 = 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 == (lang_output_section_statement_type *)NULL) {
    einfo("%F%P: %s uses undefined section %s\n", op, name);
  }
  if (os->processed == false) {
    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((bfd_size_type)(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 = 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 = 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)
    {
      etree_value_type other;

      other = exp_fold_tree (tree->binary.rhs,
			     current_section,
			     allocation_done, dot,dotp) ;
      if (other.valid)
	{
	  /* 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
	      && (result.section == abs_output_section
		  || other.section == abs_output_section)
	      && (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 (result.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,||);

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

  return result;
}

etree_value_type 
invalid ()
{
  etree_value_type new;
  new.valid = 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 = false;
	  }
	break;
      case DEFINED:
	if (allocation_done == lang_first_phase_enum)
	  result.valid = false;
	else
	  {
	    struct bfd_link_hash_entry *h;

	    h = bfd_link_hash_lookup (link_info.hash, 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_common));
	    result.section = 0;
	    result.valid = true;
	  }
	break;
      case NAME:
	result.valid = 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_link_hash_lookup (link_info.hash, tree->name.name,
				      false, false, true);
	    if (h != NULL && h->type == bfd_link_hash_defined)
	      {
		if (bfd_is_abs_section (h->u.def.section))
		  result = new_abs (h->u.def.value);
		else if (allocation_done == lang_final_phase_enum)
		  {
		    lang_output_section_statement_type *os;
		
		    os = (lang_output_section_statement_lookup
			  (h->u.def.section->output_section->name));

		    /* 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 =
	    lang_output_section_find(tree->name.name);
	  check(os,tree->name.name,"ADDR");
	  result =    new_rel((bfd_vma)0,  os);
	}
	else {
	  result = invalid();
	}
	break;
      case SIZEOF:
	if(allocation_done != lang_first_phase_enum) {
	  lang_output_section_statement_type *os = 
	    lang_output_section_find(tree->name.name);
	  check(os,tree->name.name,"SIZEOF");
	  result = new_abs((bfd_vma)(os->bfd_section->_raw_size));
	}
	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 == (etree_type *)NULL) {
    result.valid = false;
  }
  else {
    switch (tree->type.node_class) 
    {
     case etree_value:
      result = new_rel(tree->value.value, current_section);
      break;
    case etree_rel:
      if (allocation_done != lang_final_phase_enum)
	result.valid = false;
      else
	result = new_rel ((tree->rel.value
			   + tree->rel.section->output_section->vma
			   + tree->rel.section->output_offset),
			  current_section);
      break;
     case etree_unary:
      result = exp_fold_tree(tree->unary.child,
			     current_section,
			     allocation_done, dot, dotp);
      if (result.valid == true)
      {
	switch(tree->type.node_code) 
	{
	 case ALIGN_K:
	  if (allocation_done != lang_first_phase_enum) {
	    result = new_rel_from_section(ALIGN_N(dot,
						result.value) ,
					  current_section);

	  }
	  else {
	    result.valid = false;
	  }
	  break;
	 case ABSOLUTE:
	  if (allocation_done != lang_first_phase_enum) 
	  {
	    if (current_section 
		== (lang_output_section_statement_type*)NULL) 
	    {
	      /* Outside a section, so it's all ok */

	    }
	    else {
	      /* Inside a section, subtract the base of the section,
		 so when it's added again (in an assignment), everything comes out fine
		 */
	      result.section = abs_output_section;
	      result.value -= current_section->bfd_section->vma;
	      result.valid = true;
	    }
	  }
	  else 
	  {
	    result.valid = false;
	  }

	  break;
	 case '~':
	  make_abs(&result);
	  result.value = ~result.value;
	  break;
	 case '!':
	  make_abs(&result);
	  result.value = !result.value;
	  break;
	 case '-':
	  make_abs(&result);
	  result.value = -result.value;
	  break;
	 case NEXT:
	  if (allocation_done ==lang_allocating_phase_enum) {
	    make_abs(&result);
	    result.value = ALIGN_N(dot, result.value);
	  }
	  else {
	    /* Return next place aligned to value */
	    result.valid = false;
	  }
	  break;
	 default:
	  FAIL();
	}
      }

      break;
     case etree_trinary:

      result = exp_fold_tree(tree->trinary.cond,
			     current_section,
			     allocation_done, dot, dotp);
      if (result.valid) {
	result = exp_fold_tree(result.value ?
			       tree->trinary.lhs:tree->trinary.rhs,
			       current_section,
			       allocation_done, dot, dotp);
      }

      break;
     case etree_binary:
      result = fold_binary(tree, current_section, allocation_done,
			   dot, dotp);
      break;
     case etree_assign:
     case etree_provide:
      if (tree->assign.dst[0] == '.' && tree->assign.dst[1] == 0) {
	/* Assignment to dot can only be done during allocation */
	if (tree->type.node_class == etree_provide)
	  einfo ("%F%S can not PROVIDE assignment to location counter\n");
	if (allocation_done == lang_allocating_phase_enum) {
	  result = exp_fold_tree(tree->assign.src,
				 current_section,
				 lang_allocating_phase_enum, dot, dotp);
	  if (result.valid == false) {
	    einfo("%F%S invalid assignment to location counter\n");
	  }
	  else {
	    if (current_section ==
		(lang_output_section_statement_type  *)NULL) {
	      einfo("%F%S assignment to location counter invalid outside of SECTION\n");
	    }
	    else {
	      bfd_vma nextdot =result.value +
	       current_section->bfd_section->vma;
	      if (nextdot < dot) {
		einfo("%F%S cannot move location counter backwards (from %V to %V)\n", dot, nextdot);
	      }
	      else {
		*dotp = nextdot; 
	      }
	    }
	  }
	}
      }
      else
	{
	  result = exp_fold_tree (tree->assign.src,
				  current_section, allocation_done,
				  dot, dotp);
	  if (result.valid)
	    {
	      struct bfd_link_hash_entry *h;

	      h = bfd_link_hash_lookup (link_info.hash, tree->assign.dst,
					(tree->type.node_class == etree_assign
					 ? true : false),
					false, false);
	      if (h == (struct bfd_link_hash_entry *) NULL)
		{
		  if (tree->type.node_class == etree_assign)
		    einfo ("%P%F:%s: hash creation failed\n",
			   tree->assign.dst);
		}
	      else if (tree->type.node_class == etree_provide
		       && h->type != bfd_link_hash_undefined
		       && h->type != bfd_link_hash_common)
		{
		  /* Do nothing.  The symbol was defined by some
                     object.  */
		}
	      else
		{
		  /* FIXME: Should we worry if the symbol is already
		     defined?  */
		  h->type = bfd_link_hash_defined;
		  h->u.def.value = result.value;
		  h->u.def.section = result.section->bfd_section;
		}
	    }
	}  
      break;
     case etree_name:
      result = fold_name(tree, current_section, allocation_done, dot);
      break;
     default:
      einfo("%F%S need more of these %d\n",tree->type.node_class );

    }
  }

  return result;
}


static etree_value_type 
exp_fold_tree_no_dot (tree, current_section, allocation_done)
     etree_type *tree;
     lang_output_section_statement_type *current_section;
     lang_phase_type allocation_done;
{
return exp_fold_tree(tree, current_section, allocation_done, (bfd_vma)
		     0, (bfd_vma *)NULL);
}

etree_type *
exp_binop (code, lhs, rhs)
     int code;
     etree_type *lhs;
     etree_type *rhs;
{
  etree_type value, *new;
  etree_value_type r;

  value.type.node_code = code;
  value.binary.lhs = lhs;
  value.binary.rhs = rhs;
  value.type.node_class = etree_binary;
  r = exp_fold_tree_no_dot(&value,
			   abs_output_section,
			   lang_first_phase_enum );
  if (r.valid)
    {
      return exp_intop(r.value);
    }
  new = (etree_type *)stat_alloc((bfd_size_type)(sizeof(new->binary)));
  memcpy((char *)new, (char *)&value, sizeof(new->binary));
  return new;
}

etree_type *
exp_trinop (code, cond, lhs, rhs)
     int code;
     etree_type *cond;
     etree_type *lhs;
     etree_type *rhs;
{
  etree_type value, *new;
  etree_value_type r;
  value.type.node_code = code;
  value.trinary.lhs = lhs;
  value.trinary.cond = cond;
  value.trinary.rhs = rhs;
  value.type.node_class = etree_trinary;
  r= exp_fold_tree_no_dot(&value,  (lang_output_section_statement_type
				    *)NULL,lang_first_phase_enum);
  if (r.valid) {
    return exp_intop(r.value);
  }
  new = (etree_type *)stat_alloc((bfd_size_type)(sizeof(new->trinary)));
  memcpy((char *)new,(char *) &value, sizeof(new->trinary));
  return new;
}


etree_type *
exp_unop (code, child)
     int code;
     etree_type *child;
{
  etree_type value, *new;

  etree_value_type r;
  value.unary.type.node_code = code;
  value.unary.child = child;
  value.unary.type.node_class = etree_unary;
  r = exp_fold_tree_no_dot(&value,abs_output_section,
			   lang_first_phase_enum);
  if (r.valid) {
    return exp_intop(r.value);
  }
  new = (etree_type *)stat_alloc((bfd_size_type)(sizeof(new->unary)));
  memcpy((char *)new, (char *)&value, sizeof(new->unary));
  return new;
}


etree_type *
exp_nameop (code, name)
     int code;
     CONST char *name;
{
  etree_type value, *new;
  etree_value_type r;
  value.name.type.node_code = code;
  value.name.name = name;
  value.name.type.node_class = etree_name;


  r = exp_fold_tree_no_dot(&value,
			   (lang_output_section_statement_type *)NULL,
			   lang_first_phase_enum);
  if (r.valid) {
    return exp_intop(r.value);
  }
  new = (etree_type *)stat_alloc((bfd_size_type)(sizeof(new->name)));
  memcpy((char *)new, (char *)&value, sizeof(new->name));
  return new;

}




etree_type *
exp_assop (code, dst, src)
     int code;
     CONST char *dst;
     etree_type *src;
{
  etree_type value, *new;

  value.assign.type.node_code = code;


  value.assign.src = src;
  value.assign.dst = dst;
  value.assign.type.node_class = etree_assign;

#if 0
  if (exp_fold_tree_no_dot(&value, &result)) {
    return exp_intop(result);
  }
#endif
  new = (etree_type*)stat_alloc((bfd_size_type)(sizeof(new->assign)));
  memcpy((char *)new, (char *)&value, sizeof(new->assign));
  return new;
}

/* Handle PROVIDE.  */

etree_type *
exp_provide (dst, src)
     const char *dst;
     etree_type *src;
{
  etree_type *n;

  n = (etree_type *) stat_alloc (sizeof (n->assign));
  n->assign.type.node_code = '=';
  n->assign.type.node_class = etree_provide;
  n->assign.src = src;
  n->assign.dst = dst;
  return n;
}

void 
exp_print_tree (tree)
     etree_type *tree;
{
  switch (tree->type.node_class) {
  case etree_value:
    print_address(tree->value.value);
    return;
  case etree_rel:
    if (tree->rel.section->owner != NULL)
      fprintf (config.map_file, "%s:",
	       bfd_get_filename (tree->rel.section->owner));
    fprintf (config.map_file, "%s+", tree->rel.section->name);
    print_address (tree->rel.value);
    return;
  case etree_assign:
#if 0
    if (tree->assign.dst->sdefs != (asymbol *)NULL){
      fprintf(config.map_file,"%s (%x) ",tree->assign.dst->name,
	      tree->assign.dst->sdefs->value);
    }
    else {
      fprintf(config.map_file,"%s (UNDEFINED)",tree->assign.dst->name);
    }
#endif
    fprintf(config.map_file,"%s ",tree->assign.dst);
    exp_print_token(tree->type.node_code);
    exp_print_tree(tree->assign.src);
    break;
  case etree_provide:
    fprintf (config.map_file, "PROVIDE (%s, ", tree->assign.dst);
    exp_print_tree (tree->assign.src);
    fprintf (config.map_file, ")");
    break;
  case etree_binary:
    fprintf(config.map_file,"(");
    exp_print_tree(tree->binary.lhs);
    exp_print_token(tree->type.node_code);
    exp_print_tree(tree->binary.rhs);
    fprintf(config.map_file,")");
    break;
  case etree_trinary:
    exp_print_tree(tree->trinary.cond);
    fprintf(config.map_file,"?");
    exp_print_tree(tree->trinary.lhs);
    fprintf(config.map_file,":");
    exp_print_tree(tree->trinary.rhs);
    break;
  case etree_unary:
    exp_print_token(tree->unary.type.node_code);
    if (tree->unary.child) 
    {
      
    fprintf(config.map_file,"(");
    exp_print_tree(tree->unary.child);
    fprintf(config.map_file,")");
  }
    
    break;
  case etree_undef:
    fprintf(config.map_file,"????????");
    break;
  case etree_name:
    if (tree->type.node_code == NAME) {
      fprintf(config.map_file,"%s", tree->name.name);
    }
    else {
      exp_print_token(tree->type.node_code);
      if (tree->name.name)
      fprintf(config.map_file,"(%s)", tree->name.name);
    }
    break;
  default:
    FAIL();
    break;
  }
}




bfd_vma
exp_get_vma (tree, def, name, allocation_done)
     etree_type *tree;
      bfd_vma def;
     char *name;
     lang_phase_type allocation_done;
{
  etree_value_type r;

  if (tree != (etree_type *)NULL) {
    r = exp_fold_tree_no_dot(tree,
		 abs_output_section,
		      allocation_done);
    if (r.valid == false && name) {
      einfo("%F%S nonconstant expression for %s\n",name);
    }
    return r.value;
  }
  else {
    return def;
  }
}

int 
exp_get_value_int (tree,def,name, allocation_done)
     etree_type *tree;
     int def;
     char *name;
     lang_phase_type allocation_done;
{
  return (int)exp_get_vma(tree,(bfd_vma)def,name, allocation_done);
}


int
exp_get_abs_int (tree, def, name, allocation_done)
     etree_type *tree;
     int def;
     char *name;
     lang_phase_type allocation_done;
{
  etree_value_type res;
  res = exp_fold_tree_no_dot (tree, abs_output_section, allocation_done);

  if (res.valid)
    {
      res.value += res.section->bfd_section->vma;
    }
  else {
    einfo ("%F%S non constant expression for %s\n",name);
  }
  return res.value;
}