/* 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 . */ char other; /* As in . */ short int desc; /* As in . */ valueT value; /* As in , 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 ":". * 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 */