/* 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 2, 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_) */ 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(¬es, name, name_length); preserved_copy_of_name = obstack_finish(¬es); symbolP = (symbolS *)obstack_alloc(¬es, sizeof(symbolS)); /* symbol must be born in some fixed state. This seems as good as any. */ memset(symbolP, 0, sizeof(symbolS)); #ifdef 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); uneeded if symbol is born zeroed. */ symbolP->sy_frag = frag; /* krm: uneeded if symbol is born zeroed. 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 ":". * 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); */ #ifdef MANY_SEGMENTS #define SEG_BSS SEG_E2 #define SEG_DATA SEG_E1 #endif 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; { #ifdef STRIP_UNDERSCORE return(symbol_find_base(name, 1)); #else /* STRIP_UNDERSCORE */ return(symbol_find_base(name, 0)); #endif /* STRIP_UNDERSCORE */ } /* symbol_find() */ 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() */ /* * decode name that may have been generated by local_label_name() above. If * the name wasn't generated by local_label_name(), then return it unaltered. * This is used for error messages. */ char *decode_local_label_name(s) char *s; { char *symbol_decode; int label_number; /* int label_version; */ char *message_format = "\"%d\" (instance number %s of a local label)"; if (s[0] != 'L' || s[2] != 1) { return(s); } /* not a local_label_name() generated name. */ label_number = s[1] - '0'; (void) sprintf(symbol_decode = obstack_alloc(¬es, strlen(s + 3) + strlen(message_format) + 10), message_format, label_number, s + 3); return(symbol_decode); } /* decode_local_label_name() */ /* * Local Variables: * comment-column: 0 * fill-column: 131 * End: */ /* end: symbols.c */