540 lines
14 KiB
C
540 lines
14 KiB
C
/* subsegs.c - subsegments -
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Copyright (C) 1987, 1990, 1991, 1992, 1993, 1994
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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 published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GAS is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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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
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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/*
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* Segments & sub-segments.
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*/
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#include "as.h"
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#include "subsegs.h"
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#include "obstack.h"
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frchainS *frchain_root, *frchain_now;
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#ifndef BFD_ASSEMBLER
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#ifdef MANY_SEGMENTS
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segment_info_type segment_info[SEG_MAXIMUM_ORDINAL];
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#else
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/* Commented in "subsegs.h". */
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frchainS *data0_frchainP, *bss0_frchainP;
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#endif /* MANY_SEGMENTS */
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char *const seg_name[] =
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{
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"absolute",
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#ifdef MANY_SEGMENTS
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"e0", "e1", "e2", "e3", "e4", "e5", "e6", "e7", "e8", "e9",
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#else
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"text",
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"data",
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"bss",
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#endif /* MANY_SEGMENTS */
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"unknown",
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"ASSEMBLER-INTERNAL-LOGIC-ERROR!",
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"expr",
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"debug",
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"transfert vector preload",
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"transfert vector postload",
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"register",
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"",
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}; /* Used by error reporters, dumpers etc. */
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#else /* BFD_ASSEMBLER */
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/* Gas segment information for bfd_abs_section_ptr and
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bfd_und_section_ptr. */
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static segment_info_type *abs_seg_info;
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static segment_info_type *und_seg_info;
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#endif /* BFD_ASSEMBLER */
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static void subseg_set_rest PARAMS ((segT, subsegT));
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void
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subsegs_begin ()
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{
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/* Check table(s) seg_name[], seg_N_TYPE[] is in correct order */
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#if !defined (MANY_SEGMENTS) && !defined (BFD_ASSEMBLER)
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know (SEG_ABSOLUTE == 0);
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know (SEG_TEXT == 1);
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know (SEG_DATA == 2);
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know (SEG_BSS == 3);
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know (SEG_UNKNOWN == 4);
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know (SEG_GOOF == 5);
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know (SEG_EXPR == 6);
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know (SEG_DEBUG == 7);
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know (SEG_NTV == 8);
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know (SEG_PTV == 9);
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know (SEG_REGISTER == 10);
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know (SEG_MAXIMUM_ORDINAL == SEG_REGISTER);
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#endif
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obstack_begin (&frags, 5000);
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frchain_root = NULL;
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frchain_now = NULL; /* Warn new_subseg() that we are booting. */
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/* Fake up 1st frag. It won't be used=> is ok if obstack...
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pads the end of it for alignment. */
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frag_now = (fragS *) obstack_alloc (&frags, SIZEOF_STRUCT_FRAG);
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memset (frag_now, 0, SIZEOF_STRUCT_FRAG);
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#ifndef BFD_ASSEMBLER
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/* This 1st frag will not be in any frchain.
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We simply give subseg_new somewhere to scribble. */
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now_subseg = 42; /* Lie for 1st call to subseg_new. */
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#ifdef MANY_SEGMENTS
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{
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int i;
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for (i = SEG_E0; i < SEG_UNKNOWN; i++)
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{
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subseg_set (i, 0);
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segment_info[i].frchainP = frchain_now;
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}
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}
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#else
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subseg_set (SEG_DATA, 0); /* .data 0 */
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data0_frchainP = frchain_now;
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subseg_set (SEG_BSS, 0);
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bss0_frchainP = frchain_now;
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#endif /* ! MANY_SEGMENTS */
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#endif /* ! BFD_ASSEMBLER */
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}
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/*
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* subseg_change()
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*
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* Change the subsegment we are in, BUT DO NOT MAKE A NEW FRAG for the
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* subsegment. If we are already in the correct subsegment, change nothing.
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* This is used eg as a worker for subseg_set [which does make a new frag_now]
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* and for changing segments after we have read the source. We construct eg
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* fixSs even after the source file is read, so we do have to keep the
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* segment context correct.
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*/
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void
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subseg_change (seg, subseg)
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register segT seg;
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register int subseg;
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{
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now_seg = seg;
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now_subseg = subseg;
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#ifdef BFD_ASSEMBLER
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{
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segment_info_type *seginfo;
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seginfo = (segment_info_type *) bfd_get_section_userdata (stdoutput, seg);
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if (! seginfo)
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{
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seginfo = (segment_info_type *) xmalloc (sizeof (*seginfo));
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memset ((PTR) seginfo, 0, sizeof (*seginfo));
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seginfo->fix_root = NULL;
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seginfo->fix_tail = NULL;
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seginfo->bfd_section = seg;
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seginfo->sym = 0;
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if (seg == bfd_abs_section_ptr)
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abs_seg_info = seginfo;
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else if (seg == bfd_und_section_ptr)
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und_seg_info = seginfo;
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else
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bfd_set_section_userdata (stdoutput, seg, (PTR) seginfo);
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}
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}
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#else
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#ifdef MANY_SEGMENTS
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seg_fix_rootP = &segment_info[seg].fix_root;
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seg_fix_tailP = &segment_info[seg].fix_tail;
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#else
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if (seg == SEG_DATA)
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{
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seg_fix_rootP = &data_fix_root;
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seg_fix_tailP = &data_fix_tail;
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}
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else if (seg == SEG_TEXT)
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{
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seg_fix_rootP = &text_fix_root;
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seg_fix_tailP = &text_fix_tail;
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}
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else
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{
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know (seg == SEG_BSS);
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seg_fix_rootP = &bss_fix_root;
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seg_fix_tailP = &bss_fix_tail;
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}
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#endif
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#endif
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}
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static void
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subseg_set_rest (seg, subseg)
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segT seg;
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subsegT subseg;
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{
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long tmp; /* JF for obstack alignment hacking */
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register frchainS *frcP; /* crawl frchain chain */
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register frchainS **lastPP; /* address of last pointer */
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frchainS *newP; /* address of new frchain */
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register fragS *former_last_fragP;
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register fragS *new_fragP;
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if (frag_now) /* If not bootstrapping. */
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{
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frag_now->fr_fix = (char*) obstack_next_free (&frags) - frag_now->fr_literal;
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frag_wane (frag_now); /* Close off any frag in old subseg. */
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}
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/*
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* It would be nice to keep an obstack for each subsegment, if we swap
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* subsegments a lot. Hence we would have much fewer frag_wanes().
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*/
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{
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obstack_finish (&frags);
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/*
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* If we don't do the above, the next object we put on obstack frags
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* will appear to start at the fr_literal of the current frag.
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* Also, above ensures that the next object will begin on a
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* address that is aligned correctly for the engine that runs
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* this program.
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*/
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}
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subseg_change (seg, (int) subseg);
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/*
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* Attempt to find or make a frchain for that sub seg.
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* Crawl along chain of frchainSs, begins @ frchain_root.
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* If we need to make a frchainS, link it into correct
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* position of chain rooted in frchain_root.
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*/
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for (frcP = *(lastPP = &frchain_root);
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frcP && frcP->frch_seg <= seg;
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frcP = *(lastPP = &frcP->frch_next))
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{
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if (frcP->frch_seg == seg
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&& frcP->frch_subseg >= subseg)
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{
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break;
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}
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}
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/*
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* frcP: Address of the 1st frchainS in correct segment with
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* frch_subseg >= subseg.
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* We want to either use this frchainS, or we want
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* to insert a new frchainS just before it.
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*
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* If frcP==NULL, then we are at the end of the chain
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* of frchainS-s. A NULL frcP means we fell off the end
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* of the chain looking for a
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* frch_subseg >= subseg, so we
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* must make a new frchainS.
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*
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* If we ever maintain a pointer to
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* the last frchainS in the chain, we change that pointer
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* ONLY when frcP==NULL.
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*
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* lastPP: Address of the pointer with value frcP;
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* Never NULL.
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* May point to frchain_root.
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*
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*/
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if (!frcP
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|| (frcP->frch_seg > seg
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|| frcP->frch_subseg > subseg)) /* Kinky logic only works with 2 segments. */
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{
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/*
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* This should be the only code that creates a frchainS.
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*/
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newP = (frchainS *) obstack_alloc (&frags, sizeof (frchainS));
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memset (newP, 0, sizeof (frchainS));
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/* This begines on a good boundary because a obstack_done()
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preceeded it. It implies an obstack_done(), so we expect
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the next object allocated to begin on a correct boundary. */
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*lastPP = newP;
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newP->frch_next = frcP; /* perhaps NULL */
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(frcP = newP)->frch_subseg = subseg;
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newP->frch_seg = seg;
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newP->frch_last = NULL;
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#ifdef BFD_ASSEMBLER
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newP->fix_root = NULL;
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newP->fix_tail = NULL;
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#endif
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}
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/*
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* Here with frcP ->ing to the frchainS for subseg.
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*/
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frchain_now = frcP;
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/*
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* Make a fresh frag for the subsegment.
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*/
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/* We expect this to happen on a correct boundary since it was
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proceeded by a obstack_done(). */
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tmp = obstack_alignment_mask (&frags); /* JF disable alignment */
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obstack_alignment_mask (&frags) = 0;
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frag_now = (fragS *) obstack_alloc (&frags, SIZEOF_STRUCT_FRAG);
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memset (frag_now, 0, SIZEOF_STRUCT_FRAG);
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obstack_alignment_mask (&frags) = tmp;
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/* But we want any more chars to come immediately after the
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structure we just made. */
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new_fragP = frag_now;
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new_fragP->fr_next = NULL;
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/*
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* Append new frag to current frchain.
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*/
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former_last_fragP = frcP->frch_last;
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if (former_last_fragP)
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{
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know (former_last_fragP->fr_next == NULL);
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know (frchain_now->frch_root);
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former_last_fragP->fr_next = new_fragP;
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}
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else
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{
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frcP->frch_root = new_fragP;
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}
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frcP->frch_last = new_fragP;
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}
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/*
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* subseg_set(segT, subsegT)
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*
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* If you attempt to change to the current subsegment, nothing happens.
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*
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* In: segT, subsegT code for new subsegment.
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* frag_now -> incomplete frag for current subsegment.
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* If frag_now==NULL, then there is no old, incomplete frag, so
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* the old frag is not closed off.
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*
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* Out: now_subseg, now_seg updated.
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* Frchain_now points to the (possibly new) struct frchain for this
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* sub-segment.
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* Frchain_root updated if needed.
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*/
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#ifndef BFD_ASSEMBLER
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segT
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subseg_new (segname, subseg)
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const char *segname;
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subsegT subseg;
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{
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int i;
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for (i = 0; i < (int) SEG_MAXIMUM_ORDINAL; i++)
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{
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const char *s;
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s = segment_name ((segT) i);
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if (strcmp (segname, s) == 0
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|| (segname[0] == '.'
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&& strcmp (segname + 1, s) == 0))
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{
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subseg_set ((segT) i, subseg);
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return (segT) i;
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}
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#ifdef obj_segment_name
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s = obj_segment_name ((segT) i);
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if (strcmp (segname, s) == 0
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|| (segname[0] == '.'
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&& strcmp (segname + 1, s) == 0))
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{
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subseg_set ((segT) i, subseg);
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return (segT) i;
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}
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#endif
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}
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#ifdef obj_add_segment
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{
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segT new_seg;
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new_seg = obj_add_segment (segname);
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subseg_set (new_seg, subseg);
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return new_seg;
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}
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#else
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as_bad ("Attempt to switch to nonexistent segment \"%s\"", segname);
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return now_seg;
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#endif
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}
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void
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subseg_set (seg, subseg) /* begin assembly for a new sub-segment */
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register segT seg; /* SEG_DATA or SEG_TEXT */
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register subsegT subseg;
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{
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#ifndef MANY_SEGMENTS
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know (seg == SEG_DATA || seg == SEG_TEXT || seg == SEG_BSS);
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#endif
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if (seg != now_seg || subseg != now_subseg)
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{ /* we just changed sub-segments */
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subseg_set_rest (seg, subseg);
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}
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}
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#else /* BFD_ASSEMBLER */
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segT
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subseg_get (segname, force_new)
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const char *segname;
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int force_new;
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{
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segT secptr;
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segment_info_type *seginfo;
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const char *now_seg_name = (now_seg
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? bfd_get_section_name (stdoutput, now_seg)
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: 0);
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if (!force_new
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&& now_seg_name
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&& (now_seg_name == segname
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|| !strcmp (now_seg_name, segname)))
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return now_seg;
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if (!force_new)
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secptr = bfd_make_section_old_way (stdoutput, segname);
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else
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secptr = bfd_make_section_anyway (stdoutput, segname);
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seginfo = seg_info (secptr);
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if (! seginfo)
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{
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/* Check whether output_section is set first because secptr may
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be bfd_abs_section_ptr. */
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if (secptr->output_section != secptr)
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secptr->output_section = secptr;
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seginfo = (segment_info_type *) xmalloc (sizeof (*seginfo));
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memset ((PTR) seginfo, 0, sizeof (*seginfo));
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seginfo->fix_root = NULL;
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seginfo->fix_tail = NULL;
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seginfo->bfd_section = secptr;
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if (secptr == bfd_abs_section_ptr)
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abs_seg_info = seginfo;
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else if (secptr == bfd_und_section_ptr)
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und_seg_info = seginfo;
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else
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bfd_set_section_userdata (stdoutput, secptr, (PTR) seginfo);
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seginfo->frchainP = NULL;
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seginfo->lineno_list_head = seginfo->lineno_list_tail = NULL;
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seginfo->sym = NULL;
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seginfo->dot = NULL;
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}
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return secptr;
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}
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segT
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subseg_new (segname, subseg)
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const char *segname;
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subsegT subseg;
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{
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segT secptr;
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segment_info_type *seginfo;
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secptr = subseg_get (segname, 0);
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subseg_set_rest (secptr, subseg);
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seginfo = seg_info (secptr);
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if (! seginfo->frchainP)
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seginfo->frchainP = frchain_now;
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return secptr;
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}
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/* Like subseg_new, except a new section is always created, even if
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a section with that name already exists. */
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segT
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subseg_force_new (segname, subseg)
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const char *segname;
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subsegT subseg;
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{
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segT secptr;
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segment_info_type *seginfo;
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secptr = subseg_get (segname, 1);
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subseg_set_rest (secptr, subseg);
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seginfo = seg_info (secptr);
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if (! seginfo->frchainP)
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seginfo->frchainP = frchain_now;
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return secptr;
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}
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void
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subseg_set (secptr, subseg)
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segT secptr;
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subsegT subseg;
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{
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if (! (secptr == now_seg && subseg == now_subseg))
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subseg_set_rest (secptr, subseg);
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}
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#ifndef obj_sec_sym_ok_for_reloc
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#define obj_sec_sym_ok_for_reloc(SEC) 0
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#endif
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/* Get the gas information we are storing for a section. */
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segment_info_type *
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seg_info (sec)
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segT sec;
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{
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if (sec == bfd_abs_section_ptr)
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return abs_seg_info;
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else if (sec == bfd_und_section_ptr)
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return und_seg_info;
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else
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return (segment_info_type *) bfd_get_section_userdata (stdoutput, sec);
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}
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symbolS *
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section_symbol (sec)
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segT sec;
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{
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segment_info_type *seginfo = seg_info (sec);
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symbolS *s;
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if (seginfo == 0)
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abort ();
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if (seginfo->sym)
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return seginfo->sym;
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s = symbol_find (sec->name);
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if (!s)
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{
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#ifndef EMIT_SECTION_SYMBOLS
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||
#define EMIT_SECTION_SYMBOLS 1
|
||
#endif
|
||
|
||
if (EMIT_SECTION_SYMBOLS
|
||
#ifdef BFD_ASSEMBLER
|
||
&& symbol_table_frozen
|
||
#endif
|
||
)
|
||
s = symbol_new (sec->name, sec, 0, &zero_address_frag);
|
||
else
|
||
s = symbol_create (sec->name, sec, 0, &zero_address_frag);
|
||
S_CLEAR_EXTERNAL (s);
|
||
|
||
/* Use the BFD section symbol, if possible. */
|
||
if (obj_sec_sym_ok_for_reloc (sec))
|
||
s->bsym = sec->symbol;
|
||
}
|
||
seginfo->sym = s;
|
||
return s;
|
||
}
|
||
|
||
#endif /* BFD_ASSEMBLER */
|
||
|
||
/* end of subsegs.c */
|