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+/* 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 */