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/* symbols.c -symbol table-
Copyright (C) 1987 Free Software Foundation, Inc.
This file is part of GAS, the GNU Assembler.
GAS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
any later version.
GAS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GAS; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include <stdlib.h>
#include <string.h>
#include "as.h"
#include "hash.h"
#include "obstack.h" /* For "symbols.h" */
#include "struc-symbol.h"
#include "symbols.h"
#include "frags.h"
#include "expr.h"
#include "sections.h"
#include "read.h"
#include "xmalloc.h"
#include "messages.h"
#include "fixes.h"
#include "input-scrub.h"
/* symbol-name => struct symbol pointer */
struct hash_control *sy_hash = NULL;
/* FixS & symbols live here */
struct obstack notes = { 0 };
/* all the symbol nodes */
symbolS *symbol_rootP = NULL;
/* last struct symbol we made, or NULL */
symbolS *symbol_lastP = NULL;
symbolS abs_symbol = { 0 };
/*
* Un*x idea of local labels. They are made by "n:" where n
* is any decimal digit. Refer to them with
* "nb" for previous (backward) n:
* or "nf" for next (forward) n:.
*
* Like Un*x AS, we have one set of local label counters for entire assembly,
* not one set per (sub)segment like in most assemblers. This implies that
* one can refer to a label in another segment, and indeed some crufty
* compilers have done just that.
*
* I document the symbol names here to save duplicating words elsewhere.
* The mth occurence of label n: is turned into the symbol "Ln^Am" where
* n is a digit and m is a decimal number. "L" makes it a label discarded
* unless debugging and "^A"('\1') ensures no ordinary symbol SHOULD get the
* same name as a local label symbol. The first "4:" is "L4^A1" - the m
* numbers begin at 1.
*/
typedef short unsigned int local_label_countT;
static local_label_countT local_label_counter[10];
static /* Returned to caller, then copied. */
char symbol_name_build[12]; /* used for created names ("4f") */
static void make_stab_for_symbol(
symbolS *symbolP);
void
symbol_begin(
void)
{
symbol_lastP = NULL;
symbol_rootP = NULL; /* In case we have 0 symbols (!!) */
sy_hash = hash_new();
memset((char *)(&abs_symbol), '\0', sizeof(abs_symbol));
abs_symbol.sy_type = N_ABS; /* Can't initialise a union. Sigh. */
memset((char *)(local_label_counter), '\0', sizeof(local_label_counter) );
}
/*
* local_label_name()
*
* Caller must copy returned name: we re-use the area for the next name.
*/
char * /* Return local label name. */
local_label_name(
int n, /* we just saw "n:", "nf" or "nb" : n a digit */
int augend) /* 0 for nb, 1 for n:, nf */
{
register char * p;
register char * q;
char symbol_name_temporary[10]; /* build up a number, BACKWARDS */
know( n >= 0 );
know( augend == 0 || augend == 1 );
p = symbol_name_build;
* p ++ = 'L';
* p ++ = n + '0'; /* Make into ASCII */
* p ++ = 1; /* ^A */
n = local_label_counter [ n ] + augend;
/* version number of this local label */
/*
* Next code just does sprintf( {}, "%d", n);
* It is more elegant to do the next part recursively, but a procedure
* call for each digit emitted is considered too costly.
*/
q = symbol_name_temporary;
for (*q++=0; n; q++) /* emits NOTHING if n starts as 0 */
{
know(n>0); /* We expect n > 0 always */
*q = n % 10 + '0';
n /= 10;
}
while (( * p ++ = * -- q ))
{
}
/* The label, as a '\0' ended string, starts at symbol_name_build. */
return (symbol_name_build);
}
void
local_colon(
int n) /* just saw "n:" */
{
local_label_counter [n] ++;
colon (local_label_name (n, 0));
}
/*
* symbol_new()
*
* Return a pointer to a new symbol.
* Die if we can't make a new symbol.
* Fill in the symbol's values.
* Add symbol to end of symbol chain.
*
*
* Please always call this to create a new symbol.
*
* Changes since 1985: Symbol names may not contain '\0'. Sigh.
*/
symbolS *
symbol_new(
char *name, /* We copy this: OK to alter your copy. */
unsigned char type, /* As in <nlist.h>. */
char other, /* As in <nlist.h>. */
short desc, /* As in <nlist.h>. */
valueT value, /* As in <nlist.h>, often an address. */
/* Often used as offset from frag address. */
struct frag *frag) /* For sy_frag. */
{
register symbolS * symbolP;
register char * preserved_copy_of_name;
register unsigned int name_length;
char * p;
name_length = strlen(name) + 1;
obstack_grow(¬es,name,name_length);
p=obstack_finish(¬es);
/* obstack_1done( ¬es, name, name_length, &p ); */
preserved_copy_of_name = p;
p=obstack_alloc(¬es,sizeof(struct symbol));
/* obstack_1blank( ¬es, sizeof(struct symbol), &p ); */
symbolP = (symbolS *) p;
symbolP -> sy_name = preserved_copy_of_name;
symbolP -> sy_type = type;
symbolP -> sy_other = other;
symbolP -> sy_desc = desc;
symbolP -> sy_value = value;
symbolP -> sy_frag = frag;
symbolP -> sy_next = NULL; /* End of chain. */
symbolP -> sy_forward = NULL; /* JF */
#ifdef SUSPECT
symbolP -> sy_name_offset = ~ 0; /* Impossible offset catches errors. */
symbolP -> sy_number = ~ 0; /* Ditto. */
#endif
/*
* Link to end of symbol chain.
*/
if (symbol_lastP)
{
symbol_lastP -> sy_next = symbolP;
}
else
{
symbol_rootP = symbolP;
}
symbol_lastP = symbolP;
return (symbolP);
}
/*
* colon()
*
* We have just seen "<name>:".
* Creates a struct symbol unless it already exists.
*
* Gripes if we are redefining a symbol incompatibly (and ignores it).
*
*/
void
colon( /* just seen "x:" - rattle symbols & frags */
char *sym_name) /* symbol name, as a cannonical string */
/* We copy this string: OK to alter later. */
{
register struct symbol * symbolP; /* symbol we are working with */
if (frchain_now == NULL)
{
know(flagseen['n']);
as_fatal("with -n a section directive must be seen before assembly "
"can begin");
}
if ((symbolP = symbol_table_lookup( sym_name )))
{
/*
* Now check for undefined symbols
*/
if ((symbolP -> sy_type & N_TYPE) == N_UNDF)
{
if( symbolP -> sy_other == 0
&& symbolP -> sy_desc == 0
&& symbolP -> sy_value == 0)
{
symbolP -> sy_frag = frag_now;
symbolP -> sy_value = obstack_next_free(& frags) - frag_now -> fr_literal;
know( N_UNDF == 0 );
symbolP -> sy_type |= N_SECT; /* keep N_EXT bit */
symbolP -> sy_other = frchain_now->frch_nsect;
#ifdef NeXT /* generate stabs for debugging assembly code */
if(flagseen['g'])
make_stab_for_symbol(symbolP);
#endif
}
else
{
as_fatal( "Symbol \"%s\" is already defined as \"%s\"/%d.%d.%ld.",
sym_name,
seg_name [(int) N_TYPE_seg [symbolP -> sy_type & N_TYPE]],
symbolP -> sy_other, symbolP -> sy_desc,
symbolP -> sy_value);
}
}
else
{
as_fatal("Symbol %s already defined.",sym_name);
}
}
else
{
symbolP = symbol_new (sym_name,
N_SECT,
frchain_now->frch_nsect,
0,
(valueT)(obstack_next_free(&frags)-frag_now->fr_literal),
frag_now);
symbol_table_insert (symbolP);
#ifdef NeXT /* generate stabs for debugging assembly code */
if(flagseen['g'])
make_stab_for_symbol(symbolP);
#endif
}
}
/*
* symbol_table_insert()
*
* Die if we can't insert the symbol.
*
*/
void
symbol_table_insert(
struct symbol *symbolP)
{
register char * error_string;
know( symbolP );
know( symbolP -> sy_name );
if ( * (error_string = hash_jam (sy_hash, symbolP -> sy_name, (char *)symbolP)))
{
as_fatal( "Inserting \"%s\" into symbol table failed: %s",
symbolP -> sy_name, error_string);
}
}
/*
* symbol_find_or_make()
*
* If a symbol name does not exist, create it as undefined, and insert
* it into the symbol table. Return a pointer to it.
*/
symbolS *
symbol_find_or_make(
char *name)
{
register symbolS * symbolP;
symbolP = symbol_table_lookup (name);
if (symbolP == NULL)
{
symbolP = symbol_new (name, N_UNDF, 0, 0, 0, & zero_address_frag);
symbol_table_insert (symbolP);
}
return (symbolP);
}
/*
* symbol_find()
*
* Implement symbol table lookup.
* In: A symbol's name as a string: '\0' can't be part of a symbol name.
* Out: NULL if the name was not in the symbol table, else the address
* of a struct symbol associated with that name.
*/
symbolS *
symbol_find(
char *name)
{
return ( (symbolS *) hash_find( sy_hash, name ));
}
#ifdef NeXT /* generate stabs for debugging assembly code */
/*
* make_stab_for_symbol() is called when -g is present for a label that is
* being defined. If the label is a text label and in the (__TEXT,__text)
* section and not a local label create a stab for it.
*
* See the detailed comments about stabs in read_a_source_file() for a
* description of what is going on here.
*/
static
void
make_stab_for_symbol(
symbolS *symbolP)
{
symbolS *stab;
int stabnamelen;
char *stabname;
if(symbolP->sy_name[0] == 'L')
return;
if((symbolP->sy_type & N_TYPE) != N_SECT)
return;
if(symbolP->sy_other != text_nsect)
return;
stabnamelen = strlen(symbolP->sy_name) + sizeof(":f3");
stabname = xmalloc(stabnamelen);
strcpy(stabname, symbolP->sy_name);
if(symbolP->sy_type & N_EXT)
strcat(stabname, ":F3");
else
strcat(stabname, ":f3");
stab = symbol_new(
stabname,
36, /* N_FUN */
text_nsect, /* n_sect */
logical_input_line, /* n_desc, line number */
symbolP->sy_value,
symbolP->sy_frag);
free(stabname);
}
#endif /* NeXT generate stabs for debugging assembly code */
/*
* indirect_symbol_new()
*
* Return a pointer to a new indirect_symbol.
* Die if we can't make a new indirect_symbol.
* Fill in the indirect_symbol's values.
* Add symbol to end of section's indirect symbol chain.
*/
isymbolS *
indirect_symbol_new(
char *name, /* We copy this: OK to alter your copy. */
struct frag *frag, /* For sy_frag. */
unsigned long offset) /* Offset from frag address. */
{
isymbolS *isymbolP;
char *preserved_copy_of_name;
unsigned long name_length;
char *p;
unsigned long stride;
struct frag *fr_next;
name_length = strlen(name) + 1;
obstack_grow(¬es, name, name_length);
p = obstack_finish(¬es);
preserved_copy_of_name = p;
p = obstack_alloc(¬es, sizeof(struct indirect_symbol));
isymbolP = (isymbolS *)p;
isymbolP->isy_name = preserved_copy_of_name;
isymbolP->isy_offset = offset;
isymbolP->isy_frag = frag;
isymbolP->isy_next = NULL; /* End of chain. */
isymbolP->isy_symbol = NULL;
/*
* Link to end of indirect symbol chain and check for missing indirect
* symbols.
*/
if(frchain_now->frch_isym_root == NULL){
if(offset != 0)
as_warn("missing or bad indirect symbol for section (%s,%s)",
frchain_now->frch_section.segname,
frchain_now->frch_section.sectname);
frchain_now->frch_isym_root = isymbolP;
frchain_now->frch_isym_last = isymbolP;
}
else{
if(frag == frchain_now->frch_isym_last->isy_frag){
if((frchain_now->frch_section.flags & SECTION_TYPE) ==
S_SYMBOL_STUBS)
stride = frchain_now->frch_section.reserved2;
else
stride = sizeof(unsigned long);
if(offset - frchain_now->frch_isym_last->isy_offset != stride)
as_warn("missing or bad indirect symbol for section "
"(%s,%s)", frchain_now->frch_section.segname,
frchain_now->frch_section.sectname);
}
else{
fr_next = frchain_now->frch_isym_last->isy_frag->fr_next;
/*
* Because of section changes there maybe some zero length
* frags after the last one that passed through here. So skip
* them and get to the last real one.
*/
while(fr_next->fr_fix == 0 &&
fr_next->fr_type == rs_fill &&
fr_next->fr_next != NULL)
fr_next = fr_next->fr_next;
if(frag != fr_next || offset != 0)
as_warn("missing or bad indirect symbol for section "
"(%s,%s)", frchain_now->frch_section.segname,
frchain_now->frch_section.sectname);
}
frchain_now->frch_isym_last->isy_next = isymbolP;
frchain_now->frch_isym_last = isymbolP;
}
return(isymbolP);
}
/* end: symbols.c */
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.