325 lines
8.4 KiB
C
325 lines
8.4 KiB
C
/* b.out object file format
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Copyright 1989, 1990, 1991, 1992, 1993, 1994, 1996, 2000, 2001, 2002,
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2003, 2005 Free Software Foundation, Inc.
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This file is part of GAS, the GNU Assembler.
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GAS is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2,
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or (at your option) any later version.
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GAS is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GAS; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
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02110-1301, USA. */
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#include "as.h"
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#include "obstack.h"
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/* In: segT Out: N_TYPE bits. */
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const short seg_N_TYPE[] =
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{
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N_ABS,
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N_TEXT,
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N_DATA,
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N_BSS,
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N_UNDF, /* Unknown. */
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N_UNDF, /* Error. */
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N_UNDF, /* Expression. */
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N_UNDF, /* Debug. */
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N_UNDF, /* Ntv. */
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N_UNDF, /* Ptv. */
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N_REGISTER, /* Register. */
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};
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const segT N_TYPE_seg[N_TYPE + 2] =
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{ /* N_TYPE == 0x1E = 32-2 */
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SEG_UNKNOWN, /* N_UNDF == 0 */
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SEG_GOOF,
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SEG_ABSOLUTE, /* N_ABS == 2 */
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SEG_GOOF,
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SEG_TEXT, /* N_TEXT == 4 */
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SEG_GOOF,
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SEG_DATA, /* N_DATA == 6 */
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SEG_GOOF,
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SEG_BSS, /* N_BSS == 8 */
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SEG_GOOF,
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SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF,
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SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF,
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SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF,
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SEG_REGISTER, /* Dummy N_REGISTER for regs = 30. */
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SEG_GOOF,
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};
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/* Relocation. */
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/* Crawl along a fixS chain. Emit the segment's relocations. */
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void
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obj_emit_relocations (char **where,
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fixS *fixP, /* Fixup chain for this segment. */
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relax_addressT segment_address_in_file)
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{
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for (; fixP; fixP = fixP->fx_next)
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{
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if (fixP->fx_done == 0
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|| fixP->fx_r_type != NO_RELOC)
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{
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symbolS *sym;
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sym = fixP->fx_addsy;
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while (sym->sy_value.X_op == O_symbol
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&& (! S_IS_DEFINED (sym) || S_IS_COMMON (sym)))
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sym = sym->sy_value.X_add_symbol;
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fixP->fx_addsy = sym;
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tc_bout_fix_to_chars (*where, fixP, segment_address_in_file);
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*where += md_reloc_size;
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}
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}
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}
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/* Aout file generation & utilities . */
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/* Convert a lvalue to machine dependent data. */
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void
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obj_header_append (char **where, object_headers *headers)
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{
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/* Always leave in host byte order. */
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char *p;
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headers->header.a_talign = section_alignment[SEG_TEXT];
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/* Force to at least 2. */
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if (headers->header.a_talign < 2)
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headers->header.a_talign = 2;
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headers->header.a_dalign = section_alignment[SEG_DATA];
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headers->header.a_balign = section_alignment[SEG_BSS];
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headers->header.a_tload = 0;
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headers->header.a_dload =
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md_section_align (SEG_DATA, H_GET_TEXT_SIZE (headers));
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headers->header.a_relaxable = linkrelax;
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p = *where;
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host_number_to_chars (p, headers->header.a_magic, 4);
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p += 4;
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host_number_to_chars (p, headers->header.a_text, 4);
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p += 4;
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host_number_to_chars (p, headers->header.a_data, 4);
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p += 4;
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host_number_to_chars (p, headers->header.a_bss, 4);
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p += 4;
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host_number_to_chars (p, headers->header.a_syms, 4);
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p += 4;
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host_number_to_chars (p, headers->header.a_entry, 4);
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p += 4;
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host_number_to_chars (p, headers->header.a_trsize, 4);
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p += 4;
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host_number_to_chars (p, headers->header.a_drsize, 4);
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p += 4;
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host_number_to_chars (p, headers->header.a_tload, 4);
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p += 4;
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host_number_to_chars (p, headers->header.a_dload, 4);
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p += 4;
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*p++ = headers->header.a_talign;
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*p++ = headers->header.a_dalign;
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*p++ = headers->header.a_balign;
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*p++ = headers->header.a_relaxable;
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*where = p;
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}
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void
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obj_symbol_to_chars (char **where, symbolS *symbolP)
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{
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char *p = *where;
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host_number_to_chars (p, S_GET_OFFSET (symbolP), 4);
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p += 4;
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/* Can't use S_GET_TYPE here as it masks. */
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*p++ = symbolP->sy_symbol.n_type;
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*p++ = symbolP->sy_symbol.n_other;
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host_number_to_chars (p, S_GET_DESC (symbolP), 2);
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p += 2;
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host_number_to_chars (p, S_GET_VALUE (symbolP), 4);
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p += 4;
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*where = p;
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}
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void
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obj_emit_symbols (char **where, symbolS *symbol_rootP)
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{
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symbolS *symbolP;
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/* Emit all symbols left in the symbol chain. */
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for (symbolP = symbol_rootP; symbolP; symbolP = symbol_next (symbolP))
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{
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/* Used to save the offset of the name. It is used to point to
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the string in memory but must be a file offset. */
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char *temp;
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temp = S_GET_NAME (symbolP);
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S_SET_OFFSET (symbolP, symbolP->sy_name_offset);
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/* Any symbol still undefined and is not a dbg symbol is made N_EXT. */
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if (!S_IS_DEBUG (symbolP) && !S_IS_DEFINED (symbolP))
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S_SET_EXTERNAL (symbolP);
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obj_symbol_to_chars (where, symbolP);
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S_SET_NAME (symbolP, temp);
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}
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}
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void
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obj_symbol_new_hook (symbolS *symbolP)
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{
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S_SET_OTHER (symbolP, 0);
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S_SET_DESC (symbolP, 0);
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}
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static void
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obj_bout_line (int ignore ATTRIBUTE_UNUSED)
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{
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/* Assume delimiter is part of expression. */
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/* BSD4.2 as fails with delightful bug, so we are not being
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incompatible here. */
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new_logical_line (NULL, (int) (get_absolute_expression ()));
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demand_empty_rest_of_line ();
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}
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void
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obj_read_begin_hook (void)
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{
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}
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void
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obj_crawl_symbol_chain (object_headers *headers)
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{
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symbolS **symbolPP;
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symbolS *symbolP;
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int symbol_number = 0;
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tc_crawl_symbol_chain (headers);
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symbolPP = &symbol_rootP; /* -> last symbol chain link. */
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while ((symbolP = *symbolPP) != NULL)
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{
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if (flag_readonly_data_in_text && (S_GET_SEGMENT (symbolP) == SEG_DATA))
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{
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S_SET_SEGMENT (symbolP, SEG_TEXT);
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}
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resolve_symbol_value (symbolP);
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/* Skip symbols which were equated to undefined or common
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symbols. */
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if (symbolP->sy_value.X_op == O_symbol
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&& (! S_IS_DEFINED (symbolP) || S_IS_COMMON (symbolP)))
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{
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*symbolPP = symbol_next (symbolP);
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continue;
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}
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/* OK, here is how we decide which symbols go out into the
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brave new symtab. Symbols that do are:
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* symbols with no name (stabd's?)
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* symbols with debug info in their N_TYPE
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Symbols that don't are:
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* symbols that are registers
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* symbols with \1 as their 3rd character (numeric labels)
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* "local labels" as defined by S_LOCAL_NAME(name)
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if the -L switch was passed to gas.
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All other symbols are output. We complain if a deleted
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symbol was marked external. */
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if (1
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&& !S_IS_REGISTER (symbolP)
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&& (!S_GET_NAME (symbolP)
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|| S_IS_DEBUG (symbolP)
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#ifdef TC_I960
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/* FIXME-SOON this ifdef seems highly dubious to me. xoxorich. */
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|| !S_IS_DEFINED (symbolP)
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|| S_IS_EXTERNAL (symbolP)
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#endif
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|| (S_GET_NAME (symbolP)[0] != '\001'
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&& (flag_keep_locals || !S_LOCAL_NAME (symbolP)))))
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{
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symbolP->sy_number = symbol_number++;
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/* The + 1 after strlen account for the \0 at the end of
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each string. */
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if (!S_IS_STABD (symbolP))
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{
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/* Ordinary case. */
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symbolP->sy_name_offset = string_byte_count;
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string_byte_count += strlen (S_GET_NAME (symbolP)) + 1;
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}
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else /* .Stabd case. */
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symbolP->sy_name_offset = 0;
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symbolPP = &(symbolP->sy_next);
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}
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else
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{
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if (S_IS_EXTERNAL (symbolP) || !S_IS_DEFINED (symbolP))
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as_bad (_("Local symbol %s never defined"),
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S_GET_NAME (symbolP));
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/* Unhook it from the chain. */
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*symbolPP = symbol_next (symbolP);
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}
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}
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H_SET_SYMBOL_TABLE_SIZE (headers, symbol_number);
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}
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/* Find strings by crawling along symbol table chain. */
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void
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obj_emit_strings (char **where)
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{
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symbolS *symbolP;
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md_number_to_chars (*where, string_byte_count, 4);
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*where += 4;
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for (symbolP = symbol_rootP; symbolP; symbolP = symbol_next (symbolP))
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if (S_GET_NAME (symbolP))
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append (where, S_GET_NAME (symbolP),
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(unsigned long) (strlen (S_GET_NAME (symbolP)) + 1));
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}
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const pseudo_typeS obj_pseudo_table[] =
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{
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{"line", obj_bout_line, 0}, /* Source code line number. */
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/* COFF debugging directives. Currently ignored silently. */
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{"def", s_ignore, 0},
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{"dim", s_ignore, 0},
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{"endef", s_ignore, 0},
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{"ln", s_ignore, 0},
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{"scl", s_ignore, 0},
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{"size", s_ignore, 0},
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{"tag", s_ignore, 0},
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{"type", s_ignore, 0},
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{"val", s_ignore, 0},
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/* Other stuff we don't handle. */
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{"ABORT", s_ignore, 0},
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{"ident", s_ignore, 0},
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{NULL, NULL, 0}
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};
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