4.4BSD/usr/src/contrib/gas-1.38/symbols.c
/* 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 "as.h"
#include "hash.h"
#include "obstack.h" /* For "symbols.h" */
#include "struc-symbol.h"
#include "symbols.h"
#include "frags.h"
#ifndef WORKING_DOT_WORD
extern int new_broken_words;
#endif
#ifdef VMS
extern char const_flag;
#endif
static
struct hash_control *
sy_hash; /* symbol-name => struct symbol pointer */
/* Below are commented in "symbols.h". */
unsigned int local_bss_counter;
symbolS * symbol_rootP;
symbolS * symbol_lastP;
symbolS abs_symbol;
struct obstack notes;
symbolS * symbol_find(); /* Keep C compiler happy. */
/*
* 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") */
#ifdef SUN_ASM_SYNTAX
int local_label_defined[10];
#endif
void
symbol_begin()
{
symbol_lastP = NULL;
symbol_rootP = NULL; /* In case we have 0 symbols (!!) */
sy_hash = hash_new();
bzero ((char *)(& abs_symbol), sizeof(abs_symbol));
abs_symbol . sy_type = N_ABS; /* Can't initialise a union. Sigh. */
bzero ((char *)(local_label_counter), sizeof(local_label_counter) );
local_bss_counter = 0;
}
/*
* 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(n, augend)
register int n; /* we just saw "n:", "nf" or "nb" : n a digit */
register 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 (n)
int n; /* just saw "n:" */
{
local_label_counter [n] ++;
#ifdef SUN_ASM_SYNTAX
local_label_defined[n]=1;
#endif
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 (name, type, other, desc, value, frag)
char * name; /* We copy this: OK to alter your copy. */
unsigned char type; /* As in <a.out.h>. */
char other; /* As in <a.out.h>. */
short int desc; /* As in <a.out.h>. */
valueT value; /* As in <a.out.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 (sym_name) /* just seen "x:" - rattle symbols & frags */
register 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 */
#ifdef SUN_ASM_SYNTAX
/* Sun local labes go out of scope whenever a non-local symbol is
defined. */
if(*sym_name !='L')
bzero((void *)local_label_defined,sizeof(local_label_defined));
#endif
#ifndef WORKING_DOT_WORD
if(new_broken_words) {
struct broken_word *a;
int possible_bytes;
fragS *frag_tmp;
char *frag_opcode;
extern md_short_jump_size;
extern md_long_jump_size;
possible_bytes=md_short_jump_size+new_broken_words*md_long_jump_size;
frag_tmp=frag_now;
frag_opcode=frag_var(rs_broken_word,possible_bytes,possible_bytes,(relax_substateT)0,(symbolS *)broken_words,(long int)0,(char *)0);
/* We want to store the pointer to where to insert the jump table in the
fr_opcode of the rs_broken_word frag. This requires a little hackery */
while(frag_tmp && (frag_tmp->fr_type!=rs_broken_word || frag_tmp->fr_opcode))
frag_tmp=frag_tmp->fr_next;
know(frag_tmp);
frag_tmp->fr_opcode=frag_opcode;
new_broken_words = 0;
for(a=broken_words;a && a->dispfrag==0;a=a->next_broken_word)
a->dispfrag=frag_tmp;
}
#endif
if (symbolP = symbol_table_lookup( sym_name ))
{
#ifdef VMS
/*
* If the new symbol is .comm AND it has a size of zero,
* we ignore it (i.e. the old symbol overrides it)
*/
if ((seg_N_TYPE [(int) now_seg] == (N_UNDF | N_EXT)) &&
((obstack_next_free(& frags) - frag_now -> fr_literal) == 0))
return;
/*
* If the old symbol is .comm and it has a size of zero,
* we override it with the new symbol value.
*/
if ((symbolP -> sy_type == (N_UNDF | N_EXT)) &&
(symbolP->sy_value == 0)) {
symbolP -> sy_frag = frag_now;
symbolP -> sy_other = const_flag;
symbolP -> sy_value = obstack_next_free(& frags) - frag_now -> fr_literal;
symbolP -> sy_type |= seg_N_TYPE [(int) now_seg]; /* keep N_EXT bit */
return;
}
#endif /* VMS */
/*
* 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;
#ifdef VMS
symbolP -> sy_other = const_flag;
#endif
symbolP -> sy_value = obstack_next_free(& frags) - frag_now -> fr_literal;
know( N_UNDF == 0 );
symbolP -> sy_type |= seg_N_TYPE [(int) now_seg]; /* keep N_EXT bit */
}
else
{
#ifdef VMS
/*
* There are still several cases to check:
* A .comm/.lcomm symbol being redefined as
* initialized data is OK
* A .comm/.lcomm symbol being redefined with
* a larger size is also OK
*/
char New_Type = seg_N_TYPE [(int) now_seg];
if (((symbolP->sy_type == (N_UNDF | N_EXT)) ||
(symbolP->sy_type == N_BSS)) &&
(((New_Type & ~N_EXT) == N_DATA) ||
(New_Type == symbolP->sy_type))) {
/*
* Select which of the 2 cases this is
*/
if (New_Type == symbolP->sy_type) {
/*
* If the new size is larger we just
* change its value. If the new size
* is smaller, we ignore this symbol
*/
if (symbolP->sy_value <
(obstack_next_free(& frags) -
frag_now -> fr_literal)) {
symbolP -> sy_value =
obstack_next_free(& frags) -
frag_now -> fr_literal;
}
} else {
/*
* It is a .comm/.lcomm being converted
* to initialized data.
*/
symbolP -> sy_frag = frag_now;
symbolP -> sy_other = const_flag;
symbolP -> sy_value = obstack_next_free(& frags) - frag_now -> fr_literal;
symbolP -> sy_type |= seg_N_TYPE [(int) now_seg]; /* keep N_EXT bit */
}
} else {
#endif /* VMS */
as_fatal( "Symbol \"%s\" is already defined as \"%s\"/%d.%d.%d.",
sym_name,
seg_name [(int) N_TYPE_seg [symbolP -> sy_type & N_TYPE]],
symbolP -> sy_other, symbolP -> sy_desc,
symbolP -> sy_value);
#ifdef VMS
}
#endif /* VMS */
}
}
else
{
as_fatal("Symbol %s already defined.",sym_name);
}
}
else
{
symbolP = symbol_new (sym_name,
(unsigned char)(seg_N_TYPE [(int) now_seg]),
#ifdef VMS
const_flag,
#else
0,
#endif
0,
(valueT)(obstack_next_free(&frags)-frag_now->fr_literal),
frag_now);
symbol_table_insert (symbolP);
}
}
/*
* symbol_table_insert()
*
* Die if we can't insert the symbol.
*
*/
void
symbol_table_insert (symbolP)
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 (name)
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 (name)
char * name;
{
return ( (symbolS *) hash_find( sy_hash, name ));
}
/* end: symbols.c */