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binutils-gdb/gas/symbols.c

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Initial revision
1991-04-04 20:19:53 +02:00
/* symbols.c -symbol table-
Copyright (C) 1987, 1990, 1991 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. */
/* static const char rcsid[] = "$Id$"; */
#include "as.h"
#include "obstack.h" /* For "symbols.h" */
#include "subsegs.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;
symbolS* dot_text_symbol;
symbolS* dot_data_symbol;
symbolS* dot_bss_symbol;
struct obstack notes;
/*
* 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 LOCAL_LABELS_DOLLAR
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));
S_SET_SEGMENT(&abs_symbol, SEG_ABSOLUTE); /* 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 ) != '\0') ;;
/* The label, as a '\0' ended string, starts at symbol_name_build. */
return(symbol_name_build);
} /* local_label_name() */
void local_colon (n)
int n; /* just saw "n:" */
{
local_label_counter [n] ++;
#ifdef LOCAL_LABELS_DOLLAR
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.
* 2nd argument is now a SEG rather than a TYPE. The mapping between
* segments and types is mostly encapsulated herein (actually, we inherit it
* from macros in struc-symbol.h).
*/
symbolS *symbol_new(name, segment, value, frag)
char *name; /* It is copied, the caller can destroy/modify */
segT segment; /* Segment identifier (SEG_<something>) */
long value; /* Symbol value */
fragS *frag; /* Associated fragment */
{
unsigned int name_length;
char *preserved_copy_of_name;
symbolS *symbolP;
name_length = strlen(name) + 1; /* +1 for \0 */
obstack_grow(&notes, name, name_length);
preserved_copy_of_name = obstack_finish(&notes);
symbolP = (symbolS *)obstack_alloc(&notes, sizeof(symbolS));
#if STRIP_UNDERSCORE
S_SET_NAME(symbolP, (*preserved_copy_of_name == '_'
? preserved_copy_of_name + 1
: preserved_copy_of_name));
#else /* STRIP_UNDERSCORE */
S_SET_NAME(symbolP, preserved_copy_of_name);
#endif /* STRIP_UNDERSCORE */
S_SET_SEGMENT(symbolP, segment);
S_SET_VALUE(symbolP, value);
symbol_clear_list_pointers(symbolP);
symbolP->sy_frag = frag;
symbolP->sy_forward = NULL; /* JF */
symbolP->sy_number = ~0;
symbolP->sy_name_offset = ~0;
/*
* Link to end of symbol chain.
*/
symbol_append(symbolP, symbol_lastP, &symbol_rootP, &symbol_lastP);
obj_symbol_new_hook(symbolP);
#ifdef DEBUG
verify_symbol_chain(symbol_rootP, symbol_lastP);
#endif /* DEBUG */
return(symbolP);
} /* symbol_new() */
/*
* 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 symbolS * symbolP; /* symbol we are working with */
#ifdef LOCAL_LABELS_DOLLAR
/* Sun local labels 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,
0L,
NULL);
/* 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_find(sym_name)) != 0) {
#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 ((SEGMENT_TO_SYMBOL_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))
&& (S_GET_VALUE(symbolP) == 0)) {
symbolP->sy_frag = frag_now;
symbolP->sy_other = const_flag;
S_SET_VALUE(symbolP, obstack_next_free(& frags) - frag_now->fr_literal);
symbolP->sy_type |= SEGMENT_TO_SYMBOL_TYPE((int) now_seg); /* keep N_EXT bit */
return;
}
#endif /* VMS */
/*
* Now check for undefined symbols
*/
if (!S_IS_DEFINED(symbolP)) {
if (S_GET_VALUE(symbolP) == 0) {
symbolP->sy_frag = frag_now;
#ifdef VMS
symbolP->sy_other = const_flag;
#endif
S_SET_VALUE(symbolP, obstack_next_free(&frags) - frag_now->fr_literal);
S_SET_SEGMENT(symbolP, now_seg);
#ifdef N_UNDF
know(N_UNDF == 0);
#endif /* if we have one, it better be zero. */
} else {
/*
* 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
*
* This only used to be allowed on VMS gas, but Sun cc
* on the sparc also depends on it.
*/
char New_Type = SEGMENT_TO_SYMBOL_TYPE((int) now_seg);
if (((!S_IS_DEBUG(symbolP) && !S_IS_DEFINED(symbolP) && S_IS_EXTERNAL(symbolP))
|| (S_GET_SEGMENT(symbolP) == SEG_BSS))
&& ((now_seg == SEG_DATA)
|| (now_seg == S_GET_SEGMENT(symbolP)))) {
/*
* Select which of the 2 cases this is
*/
if (now_seg != SEG_DATA) {
/*
* New .comm for prev .comm symbol.
* If the new size is larger we just
* change its value. If the new size
* is smaller, we ignore this symbol
*/
if (S_GET_VALUE(symbolP)
< ((unsigned) (obstack_next_free(& frags) - frag_now->fr_literal))) {
S_SET_VALUE(symbolP,
obstack_next_free(& frags) -
frag_now->fr_literal);
}
} else {
/*
* It is a .comm/.lcomm being converted
* to initialized data.
*/
symbolP->sy_frag = frag_now;
#ifdef VMS
symbolP->sy_other = const_flag;
#endif /* VMS */
S_SET_VALUE(symbolP, obstack_next_free(& frags) - frag_now->fr_literal);
S_SET_SEGMENT(symbolP, now_seg); /* keep N_EXT bit */
}
} else {
#ifdef OBJ_COFF
as_fatal("Symbol \"%s\" is already defined as \"%s\"/%d.",
sym_name,
segment_name(S_GET_SEGMENT(symbolP)),
S_GET_VALUE(symbolP));
#else /* OBJ_COFF */
as_fatal("Symbol \"%s\" is already defined as \"%s\"/%d.%d.%d.",
sym_name,
segment_name(S_GET_SEGMENT(symbolP)),
S_GET_OTHER(symbolP), S_GET_DESC(symbolP),
S_GET_VALUE(symbolP));
#endif /* OBJ_COFF */
}
} /* if the undefined symbol has no value */
} else {
as_fatal("Symbol %s already defined.", sym_name);
} /* if this symbol is not yet defined */
} else {
symbolP = symbol_new(sym_name,
now_seg,
(valueT)(obstack_next_free(&frags)-frag_now->fr_literal),
frag_now);
#ifdef VMS
S_SET_OTHER(symbolP, const_flag);
#endif /* VMS */
symbol_table_insert(symbolP);
} /* if we have seen this symbol before */
return;
} /* colon() */
/*
* symbol_table_insert()
*
* Die if we can't insert the symbol.
*
*/
void symbol_table_insert(symbolP)
symbolS *symbolP;
{
register char *error_string;
know(symbolP);
know(S_GET_NAME(symbolP));
if (*(error_string = hash_jam(sy_hash, S_GET_NAME(symbolP), (char *)symbolP))) {
as_fatal("Inserting \"%s\" into symbol table failed: %s",
S_GET_NAME(symbolP), error_string);
} /* on error */
} /* symbol_table_insert() */
/*
* 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_find(name);
if (symbolP == NULL) {
symbolP = symbol_make(name);
symbol_table_insert(symbolP);
} /* if symbol wasn't found */
return(symbolP);
} /* symbol_find_or_make() */
symbolS *symbol_make(name)
char *name;
{
symbolS *symbolP;
/* Let the machine description default it, e.g. for register names. */
symbolP = md_undefined_symbol(name);
if (!symbolP) {
symbolP = symbol_new(name,
SEG_UNKNOWN,
0,
&zero_address_frag);
} /* if md didn't build us a symbol */
return(symbolP);
} /* symbol_make() */
/*
* 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;
{
#ifndef STRIP_UNDERSCORE
#define STRIP_UNDERSCORE 0
#endif /* STRIP_UNDERSCORE */
return symbol_find_base(name, STRIP_UNDERSCORE);
}
symbolS *symbol_find_base(name, strip_underscore)
char *name;
int strip_underscore;
{
if(strip_underscore && *name == '_') name++;
return ( (symbolS *) hash_find( sy_hash, name ));
}
/*
* Once upon a time, symbols were kept in a singly linked list. At
* least coff needs to be able to rearrange them from time to time, for
* which a doubly linked list is much more convenient. Loic did these
* as macros which seemed dangerous to me so they're now functions.
* xoxorich.
*/
/* Link symbol ADDME after symbol TARGET in the chain. */
void symbol_append(addme, target, rootPP, lastPP)
symbolS *addme;
symbolS *target;
symbolS **rootPP;
symbolS **lastPP;
{
if (target == NULL) {
know(*rootPP == NULL);
know(*lastPP == NULL);
*rootPP = addme;
*lastPP = addme;
return;
} /* if the list is empty */
if (target->sy_next != NULL) {
#ifdef SYMBOLS_NEED_BACKPOINTERS
target->sy_next->sy_previous = addme;
#endif /* SYMBOLS_NEED_BACKPOINTERS */
} else {
know(*lastPP == target);
*lastPP = addme;
} /* if we have a next */
addme->sy_next = target->sy_next;
target->sy_next = addme;
#ifdef SYMBOLS_NEED_BACKPOINTERS
addme->sy_previous = target;
#endif /* SYMBOLS_NEED_BACKPOINTERS */
#ifdef DEBUG
verify_symbol_chain(*rootPP, *lastPP);
#endif /* DEBUG */
return;
} /* symbol_append() */
#ifdef SYMBOLS_NEED_BACKPOINTERS
/* Remove SYMBOLP from the list. */
void symbol_remove(symbolP, rootPP, lastPP)
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 */