615 lines
16 KiB
C
615 lines
16 KiB
C
/* symbols.c -symbol table-
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Copyright (C) 1987, 1990, 1991 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 1, 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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/* static const char rcsid[] = "$Id$"; */
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#include "as.h"
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#include "obstack.h" /* For "symbols.h" */
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#include "subsegs.h"
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#ifndef WORKING_DOT_WORD
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extern int new_broken_words;
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#endif
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#ifdef VMS
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extern char const_flag;
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#endif
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static
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struct hash_control *
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sy_hash; /* symbol-name => struct symbol pointer */
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/* Below are commented in "symbols.h". */
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unsigned int local_bss_counter;
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symbolS * symbol_rootP;
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symbolS * symbol_lastP;
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symbolS abs_symbol;
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symbolS* dot_text_symbol;
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symbolS* dot_data_symbol;
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symbolS* dot_bss_symbol;
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struct obstack notes;
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/*
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* Un*x idea of local labels. They are made by "n:" where n
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* is any decimal digit. Refer to them with
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* "nb" for previous (backward) n:
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* or "nf" for next (forward) n:.
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*
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* Like Un*x AS, we have one set of local label counters for entire assembly,
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* not one set per (sub)segment like in most assemblers. This implies that
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* one can refer to a label in another segment, and indeed some crufty
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* compilers have done just that.
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*
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* I document the symbol names here to save duplicating words elsewhere.
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* The mth occurence of label n: is turned into the symbol "Ln^Am" where
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* n is a digit and m is a decimal number. "L" makes it a label discarded
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* unless debugging and "^A"('\1') ensures no ordinary symbol SHOULD get the
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* same name as a local label symbol. The first "4:" is "L4^A1" - the m
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* numbers begin at 1.
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*/
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typedef short unsigned int
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local_label_countT;
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static local_label_countT
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local_label_counter[10];
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static /* Returned to caller, then copied. */
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char symbol_name_build[12]; /* used for created names ("4f") */
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#ifdef LOCAL_LABELS_DOLLAR
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int local_label_defined[10];
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#endif
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void
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symbol_begin()
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{
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symbol_lastP = NULL;
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symbol_rootP = NULL; /* In case we have 0 symbols (!!) */
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sy_hash = hash_new();
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bzero ((char *)(& abs_symbol), sizeof(abs_symbol));
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S_SET_SEGMENT(&abs_symbol, SEG_ABSOLUTE); /* Can't initialise a union. Sigh. */
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bzero ((char *)(local_label_counter), sizeof(local_label_counter) );
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local_bss_counter = 0;
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}
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/*
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* local_label_name()
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*
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* Caller must copy returned name: we re-use the area for the next name.
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*/
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char * /* Return local label name. */
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local_label_name(n, augend)
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register int n; /* we just saw "n:", "nf" or "nb" : n a digit */
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register int augend; /* 0 for nb, 1 for n:, nf */
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{
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register char * p;
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register char * q;
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char symbol_name_temporary[10]; /* build up a number, BACKWARDS */
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know( n >= 0 );
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know( augend == 0 || augend == 1 );
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p = symbol_name_build;
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* p ++ = 'L';
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* p ++ = n + '0'; /* Make into ASCII */
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* p ++ = 1; /* ^A */
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n = local_label_counter [ n ] + augend;
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/* version number of this local label */
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/*
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* Next code just does sprintf( {}, "%d", n);
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* It is more elegant to do the next part recursively, but a procedure
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* call for each digit emitted is considered too costly.
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*/
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q = symbol_name_temporary;
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for (*q++=0; n; q++) /* emits NOTHING if n starts as 0 */
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{
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know(n>0); /* We expect n > 0 always */
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*q = n % 10 + '0';
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n /= 10;
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}
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while (( * p ++ = * -- q ) != '\0') ;;
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/* The label, as a '\0' ended string, starts at symbol_name_build. */
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return(symbol_name_build);
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} /* local_label_name() */
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void local_colon (n)
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int n; /* just saw "n:" */
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{
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local_label_counter [n] ++;
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#ifdef LOCAL_LABELS_DOLLAR
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local_label_defined[n]=1;
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#endif
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colon (local_label_name (n, 0));
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}
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/*
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* symbol_new()
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*
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* Return a pointer to a new symbol.
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* Die if we can't make a new symbol.
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* Fill in the symbol's values.
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* Add symbol to end of symbol chain.
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*
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*
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* Please always call this to create a new symbol.
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*
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* Changes since 1985: Symbol names may not contain '\0'. Sigh.
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* 2nd argument is now a SEG rather than a TYPE. The mapping between
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* segments and types is mostly encapsulated herein (actually, we inherit it
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* from macros in struc-symbol.h).
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*/
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symbolS *symbol_new(name, segment, value, frag)
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char *name; /* It is copied, the caller can destroy/modify */
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segT segment; /* Segment identifier (SEG_<something>) */
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long value; /* Symbol value */
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fragS *frag; /* Associated fragment */
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{
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unsigned int name_length;
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char *preserved_copy_of_name;
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symbolS *symbolP;
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name_length = strlen(name) + 1; /* +1 for \0 */
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obstack_grow(¬es, name, name_length);
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preserved_copy_of_name = obstack_finish(¬es);
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symbolP = (symbolS *)obstack_alloc(¬es, sizeof(symbolS));
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#if STRIP_UNDERSCORE
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S_SET_NAME(symbolP, (*preserved_copy_of_name == '_'
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? preserved_copy_of_name + 1
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: preserved_copy_of_name));
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#else /* STRIP_UNDERSCORE */
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S_SET_NAME(symbolP, preserved_copy_of_name);
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#endif /* STRIP_UNDERSCORE */
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S_SET_SEGMENT(symbolP, segment);
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S_SET_VALUE(symbolP, value);
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symbol_clear_list_pointers(symbolP);
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symbolP->sy_frag = frag;
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symbolP->sy_forward = NULL; /* JF */
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symbolP->sy_number = ~0;
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symbolP->sy_name_offset = ~0;
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/*
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* Link to end of symbol chain.
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*/
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symbol_append(symbolP, symbol_lastP, &symbol_rootP, &symbol_lastP);
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obj_symbol_new_hook(symbolP);
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#ifdef DEBUG
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verify_symbol_chain(symbol_rootP, symbol_lastP);
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#endif /* DEBUG */
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return(symbolP);
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} /* symbol_new() */
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/*
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* colon()
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*
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* We have just seen "<name>:".
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* Creates a struct symbol unless it already exists.
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*
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* Gripes if we are redefining a symbol incompatibly (and ignores it).
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*
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*/
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void colon(sym_name) /* just seen "x:" - rattle symbols & frags */
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register char * sym_name; /* symbol name, as a cannonical string */
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/* We copy this string: OK to alter later. */
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{
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register symbolS * symbolP; /* symbol we are working with */
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#ifdef LOCAL_LABELS_DOLLAR
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/* Sun local labels go out of scope whenever a non-local symbol is defined. */
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if(*sym_name !='L')
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bzero((void *) local_label_defined, sizeof(local_label_defined));
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#endif
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#ifndef WORKING_DOT_WORD
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if(new_broken_words) {
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struct broken_word *a;
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int possible_bytes;
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fragS *frag_tmp;
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char *frag_opcode;
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extern md_short_jump_size;
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extern md_long_jump_size;
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possible_bytes=md_short_jump_size + new_broken_words * md_long_jump_size;
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frag_tmp=frag_now;
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frag_opcode=frag_var(rs_broken_word,
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possible_bytes,
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possible_bytes,
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(relax_substateT) 0,
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(symbolS *) broken_words,
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0L,
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NULL);
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/* We want to store the pointer to where to insert the jump table in the
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fr_opcode of the rs_broken_word frag. This requires a little hackery */
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while(frag_tmp && (frag_tmp->fr_type!=rs_broken_word || frag_tmp->fr_opcode))
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frag_tmp=frag_tmp->fr_next;
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know(frag_tmp);
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frag_tmp->fr_opcode=frag_opcode;
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new_broken_words = 0;
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for(a=broken_words;a && a->dispfrag==0;a=a->next_broken_word)
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a->dispfrag=frag_tmp;
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}
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#endif
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if ((symbolP = symbol_find(sym_name)) != 0) {
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#ifdef VMS
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/*
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* If the new symbol is .comm AND it has a size of zero,
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* we ignore it (i.e. the old symbol overrides it)
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*/
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if ((SEGMENT_TO_SYMBOL_TYPE((int) now_seg) == (N_UNDF | N_EXT)) &&
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((obstack_next_free(& frags) - frag_now->fr_literal) == 0))
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return;
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/*
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* If the old symbol is .comm and it has a size of zero,
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* we override it with the new symbol value.
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*/
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if ((symbolP->sy_type == (N_UNDF | N_EXT))
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&& (S_GET_VALUE(symbolP) == 0)) {
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symbolP->sy_frag = frag_now;
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symbolP->sy_other = const_flag;
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S_SET_VALUE(symbolP, obstack_next_free(& frags) - frag_now->fr_literal);
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symbolP->sy_type |= SEGMENT_TO_SYMBOL_TYPE((int) now_seg); /* keep N_EXT bit */
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return;
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}
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#endif /* VMS */
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/*
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* Now check for undefined symbols
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*/
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if (!S_IS_DEFINED(symbolP)) {
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if (S_GET_VALUE(symbolP) == 0) {
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symbolP->sy_frag = frag_now;
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#ifdef VMS
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symbolP->sy_other = const_flag;
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#endif
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S_SET_VALUE(symbolP, obstack_next_free(&frags) - frag_now->fr_literal);
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S_SET_SEGMENT(symbolP, now_seg);
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#ifdef N_UNDF
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know(N_UNDF == 0);
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#endif /* if we have one, it better be zero. */
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} else {
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/*
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* There are still several cases to check:
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* A .comm/.lcomm symbol being redefined as
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* initialized data is OK
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* A .comm/.lcomm symbol being redefined with
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* a larger size is also OK
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*
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* This only used to be allowed on VMS gas, but Sun cc
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* on the sparc also depends on it.
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*/
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char New_Type = SEGMENT_TO_SYMBOL_TYPE((int) now_seg);
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if (((!S_IS_DEBUG(symbolP) && !S_IS_DEFINED(symbolP) && S_IS_EXTERNAL(symbolP))
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|| (S_GET_SEGMENT(symbolP) == SEG_BSS))
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&& ((now_seg == SEG_DATA)
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|| (now_seg == S_GET_SEGMENT(symbolP)))) {
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/*
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* Select which of the 2 cases this is
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*/
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if (now_seg != SEG_DATA) {
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/*
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* New .comm for prev .comm symbol.
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* If the new size is larger we just
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* change its value. If the new size
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* is smaller, we ignore this symbol
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*/
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if (S_GET_VALUE(symbolP)
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< ((unsigned) (obstack_next_free(& frags) - frag_now->fr_literal))) {
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S_SET_VALUE(symbolP,
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obstack_next_free(& frags) -
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frag_now->fr_literal);
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}
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} else {
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/*
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* It is a .comm/.lcomm being converted
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* to initialized data.
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*/
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symbolP->sy_frag = frag_now;
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#ifdef VMS
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symbolP->sy_other = const_flag;
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#endif /* VMS */
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S_SET_VALUE(symbolP, obstack_next_free(& frags) - frag_now->fr_literal);
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S_SET_SEGMENT(symbolP, now_seg); /* keep N_EXT bit */
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}
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} else {
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#ifdef OBJ_COFF
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as_fatal("Symbol \"%s\" is already defined as \"%s\"/%d.",
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sym_name,
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segment_name(S_GET_SEGMENT(symbolP)),
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S_GET_VALUE(symbolP));
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#else /* OBJ_COFF */
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as_fatal("Symbol \"%s\" is already defined as \"%s\"/%d.%d.%d.",
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sym_name,
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segment_name(S_GET_SEGMENT(symbolP)),
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S_GET_OTHER(symbolP), S_GET_DESC(symbolP),
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S_GET_VALUE(symbolP));
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#endif /* OBJ_COFF */
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}
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} /* if the undefined symbol has no value */
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} else {
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as_fatal("Symbol %s already defined.", sym_name);
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} /* if this symbol is not yet defined */
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} else {
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symbolP = symbol_new(sym_name,
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now_seg,
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(valueT)(obstack_next_free(&frags)-frag_now->fr_literal),
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frag_now);
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#ifdef VMS
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S_SET_OTHER(symbolP, const_flag);
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#endif /* VMS */
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symbol_table_insert(symbolP);
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} /* if we have seen this symbol before */
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return;
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} /* colon() */
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/*
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* symbol_table_insert()
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*
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* Die if we can't insert the symbol.
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*
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*/
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void symbol_table_insert(symbolP)
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symbolS *symbolP;
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{
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register char *error_string;
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know(symbolP);
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know(S_GET_NAME(symbolP));
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if (*(error_string = hash_jam(sy_hash, S_GET_NAME(symbolP), (char *)symbolP))) {
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as_fatal("Inserting \"%s\" into symbol table failed: %s",
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S_GET_NAME(symbolP), error_string);
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} /* on error */
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} /* symbol_table_insert() */
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/*
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* symbol_find_or_make()
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*
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* If a symbol name does not exist, create it as undefined, and insert
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* it into the symbol table. Return a pointer to it.
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*/
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symbolS *symbol_find_or_make(name)
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char *name;
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{
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register symbolS *symbolP;
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symbolP = symbol_find(name);
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if (symbolP == NULL) {
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symbolP = symbol_make(name);
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symbol_table_insert(symbolP);
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} /* if symbol wasn't found */
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return(symbolP);
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} /* symbol_find_or_make() */
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symbolS *symbol_make(name)
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char *name;
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{
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symbolS *symbolP;
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/* Let the machine description default it, e.g. for register names. */
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symbolP = md_undefined_symbol(name);
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if (!symbolP) {
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symbolP = symbol_new(name,
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SEG_UNKNOWN,
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0,
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&zero_address_frag);
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} /* if md didn't build us a symbol */
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return(symbolP);
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} /* symbol_make() */
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/*
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* symbol_find()
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*
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* Implement symbol table lookup.
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* In: A symbol's name as a string: '\0' can't be part of a symbol name.
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* Out: NULL if the name was not in the symbol table, else the address
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* of a struct symbol associated with that name.
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*/
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symbolS *symbol_find(name)
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char *name;
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{
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#ifndef STRIP_UNDERSCORE
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#define STRIP_UNDERSCORE 0
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#endif /* STRIP_UNDERSCORE */
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return symbol_find_base(name, STRIP_UNDERSCORE);
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}
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symbolS *symbol_find_base(name, strip_underscore)
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char *name;
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int strip_underscore;
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{
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if(strip_underscore && *name == '_') name++;
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return ( (symbolS *) hash_find( sy_hash, name ));
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}
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/*
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* Once upon a time, symbols were kept in a singly linked list. At
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* least coff needs to be able to rearrange them from time to time, for
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* which a doubly linked list is much more convenient. Loic did these
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* as macros which seemed dangerous to me so they're now functions.
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* xoxorich.
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*/
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/* Link symbol ADDME after symbol TARGET in the chain. */
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void symbol_append(addme, target, rootPP, lastPP)
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symbolS *addme;
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symbolS *target;
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symbolS **rootPP;
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symbolS **lastPP;
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{
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if (target == NULL) {
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know(*rootPP == NULL);
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know(*lastPP == NULL);
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*rootPP = addme;
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*lastPP = addme;
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return;
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} /* if the list is empty */
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if (target->sy_next != NULL) {
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#ifdef SYMBOLS_NEED_BACKPOINTERS
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target->sy_next->sy_previous = addme;
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#endif /* SYMBOLS_NEED_BACKPOINTERS */
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} else {
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know(*lastPP == target);
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*lastPP = addme;
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} /* if we have a next */
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addme->sy_next = target->sy_next;
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target->sy_next = addme;
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#ifdef SYMBOLS_NEED_BACKPOINTERS
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addme->sy_previous = target;
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#endif /* SYMBOLS_NEED_BACKPOINTERS */
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#ifdef DEBUG
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verify_symbol_chain(*rootPP, *lastPP);
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#endif /* DEBUG */
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return;
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} /* symbol_append() */
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#ifdef SYMBOLS_NEED_BACKPOINTERS
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/* Remove SYMBOLP from the list. */
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void symbol_remove(symbolP, rootPP, lastPP)
|
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symbolS *symbolP;
|
||
symbolS **rootPP;
|
||
symbolS **lastPP;
|
||
{
|
||
if (symbolP == *rootPP) {
|
||
*rootPP = symbolP->sy_next;
|
||
} /* if it was the root */
|
||
|
||
if (symbolP == *lastPP) {
|
||
*lastPP = symbolP->sy_previous;
|
||
} /* if it was the tail */
|
||
|
||
if (symbolP->sy_next != NULL) {
|
||
symbolP->sy_next->sy_previous = symbolP->sy_previous;
|
||
} /* if not last */
|
||
|
||
if (symbolP->sy_previous != NULL) {
|
||
symbolP->sy_previous->sy_next = symbolP->sy_next;
|
||
} /* if not first */
|
||
|
||
#ifdef DEBUG
|
||
verify_symbol_chain(*rootPP, *lastPP);
|
||
#endif /* DEBUG */
|
||
|
||
return;
|
||
} /* symbol_remove() */
|
||
|
||
/* Set the chain pointers of SYMBOL to null. */
|
||
void symbol_clear_list_pointers(symbolP)
|
||
symbolS *symbolP;
|
||
{
|
||
symbolP->sy_next = NULL;
|
||
symbolP->sy_previous = NULL;
|
||
} /* symbol_clear_list_pointers() */
|
||
|
||
/* Link symbol ADDME before symbol TARGET in the chain. */
|
||
void symbol_insert(addme, target, rootPP, lastPP)
|
||
symbolS *addme;
|
||
symbolS *target;
|
||
symbolS **rootPP;
|
||
symbolS **lastPP;
|
||
{
|
||
if (target->sy_previous != NULL) {
|
||
target->sy_previous->sy_next = addme;
|
||
} else {
|
||
know(*rootPP == target);
|
||
*rootPP = addme;
|
||
} /* if not first */
|
||
|
||
addme->sy_previous = target->sy_previous;
|
||
target->sy_previous = addme;
|
||
addme->sy_next = target;
|
||
|
||
#ifdef DEBUG
|
||
verify_symbol_chain(*rootPP, *lastPP);
|
||
#endif /* DEBUG */
|
||
|
||
return;
|
||
} /* symbol_insert() */
|
||
#endif /* SYMBOLS_NEED_BACKPOINTERS */
|
||
|
||
void verify_symbol_chain(rootP, lastP)
|
||
symbolS *rootP;
|
||
symbolS *lastP;
|
||
{
|
||
symbolS *symbolP = rootP;
|
||
|
||
if (symbolP == NULL) {
|
||
return;
|
||
} /* empty chain */
|
||
|
||
for ( ; symbol_next(symbolP) != NULL; symbolP = symbol_next(symbolP)) {
|
||
#ifdef SYMBOLS_NEED_BACKPOINTERS
|
||
/*$if (symbolP->sy_previous) {
|
||
know(symbolP->sy_previous->sy_next == symbolP);
|
||
} else {
|
||
know(symbolP == rootP);
|
||
}$*/ /* both directions */
|
||
know(symbolP->sy_next->sy_previous == symbolP);
|
||
#else /* SYMBOLS_NEED_BACKPOINTERS */
|
||
;
|
||
#endif /* SYMBOLS_NEED_BACKPOINTERS */
|
||
} /* verify pointers */
|
||
|
||
know(lastP == symbolP);
|
||
|
||
return;
|
||
} /* verify_symbol_chain() */
|
||
|
||
|
||
/*
|
||
* Local Variables:
|
||
* comment-column: 0
|
||
* fill-column: 131
|
||
* End:
|
||
*/
|
||
|
||
/* end: symbols.c */
|