X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/6390a83f8b09d6fe04c43374a69bcb3aeef50507..1485e106a4617cd9c50bcd322baa4cea81a63e50:/src/reader.c diff --git a/src/reader.c b/src/reader.c index 93df69a6..949d74bb 100644 --- a/src/reader.c +++ b/src/reader.c @@ -51,11 +51,6 @@ typedef struct symbol_list int lineno; static symbol_list *grammar = NULL; static int start_flag = 0; -static symbol_t *startval = NULL; - -/* Nonzero if components of semantic values are used, implying - they must be unions. */ -static int value_components_used; /* Nonzero if %union has been seen. */ static int typed = 0; @@ -63,11 +58,6 @@ static int typed = 0; /* Incremented for each %left, %right or %nonassoc seen */ static int lastprec = 0; -symbol_t *errtoken = NULL; -symbol_t *undeftoken = NULL; -symbol_t *eoftoken = NULL; -symbol_t *axiom = NULL; - static symbol_list * symbol_list_new (symbol_t *sym) { @@ -81,169 +71,6 @@ symbol_list_new (symbol_t *sym) return res; } -/*------------------------. -| Operations on symbols. | -`------------------------*/ - - -/*-----------------------------------------------------------. -| If THIS is not defined, report an error, and consider it a | -| nonterminal. | -`-----------------------------------------------------------*/ - -static bool -symbol_check_defined (symbol_t *this) -{ - if (this->class == unknown_sym) - { - complain - (_("symbol %s is used, but is not defined as a token and has no rules"), - this->tag); - this->class = nterm_sym; - this->number = nvars++; - } - - return TRUE; -} - - -/*-------------------------------------------------------------------. -| Assign a symbol number, and write the definition of the token name | -| into FDEFINES. Put in SYMBOLS. | -`-------------------------------------------------------------------*/ - -static bool -symbol_make_alias (symbol_t *symbol, char *typename) -{ - if (symval->alias) - warn (_("symbol `%s' used more than once as a literal string"), - symval->tag); - else if (symbol->alias) - warn (_("symbol `%s' given more than one literal string"), - symbol->tag); - else - { - symval->class = token_sym; - symval->type_name = typename; - symval->user_token_number = symbol->user_token_number; - symbol->user_token_number = USER_NUMBER_ALIAS; - symval->alias = symbol; - symbol->alias = symval; - /* symbol and symval combined are only one symbol */ - nsyms--; - ntokens--; - assert (ntokens == symbol->number || ntokens == symval->number); - symbol->number = symval->number = - (symval->number < symbol->number) ? symval->number : symbol->number; - } - - return TRUE; -} - -/*---------------------------------------------------------. -| Check that THIS, and its alias, have same precedence and | -| associativity. | -`---------------------------------------------------------*/ - -static bool -symbol_check_alias_consistence (symbol_t *this) -{ - /* Check only those who _are_ the aliases. */ - if (this->alias && this->user_token_number == USER_NUMBER_ALIAS) - { - if (this->prec != this->alias->prec) - { - if (this->prec != 0 && this->alias->prec != 0) - complain (_("conflicting precedences for %s and %s"), - this->tag, this->alias->tag); - if (this->prec != 0) - this->alias->prec = this->prec; - else - this->prec = this->alias->prec; - } - - if (this->assoc != this->alias->assoc) - { - if (this->assoc != 0 && this->alias->assoc != 0) - complain (_("conflicting assoc values for %s and %s"), - this->tag, this->alias->tag); - if (this->assoc != 0) - this->alias->assoc = this->assoc; - else - this->assoc = this->alias->assoc; - } - } - return TRUE; -} - - -/*-------------------------------------------------------------------. -| Assign a symbol number, and write the definition of the token name | -| into FDEFINES. Put in SYMBOLS. | -`-------------------------------------------------------------------*/ - -static bool -symbol_pack (symbol_t *this) -{ - if (this->class == nterm_sym) - { - this->number += ntokens; - } - else if (this->alias) - { - /* This symbol and its alias are a single token defn. - Allocate a tokno, and assign to both check agreement of - prec and assoc fields and make both the same */ - if (this->number == NUMBER_UNDEFINED) - { - if (this == eoftoken || this->alias == eoftoken) - this->number = this->alias->number = 0; - else - { - assert (this->alias->number != NUMBER_UNDEFINED); - this->number = this->alias->number; - } - } - /* Do not do processing below for USER_NUMBER_ALIASs. */ - if (this->user_token_number == USER_NUMBER_ALIAS) - return TRUE; - } - else /* this->class == token_sym */ - { - assert (this->number != NUMBER_UNDEFINED); - } - - symbols[this->number] = this; - return TRUE; -} - - - - -/*--------------------------------------------------. -| Put THIS in TOKEN_TRANSLATIONS if it is a token. | -`--------------------------------------------------*/ - -static bool -symbol_translation (symbol_t *this) -{ - /* Non-terminal? */ - if (this->class == token_sym - && this->user_token_number != USER_NUMBER_ALIAS) - { - /* A token which translation has already been set? */ - if (token_translations[this->user_token_number] != undeftoken->number) - complain (_("tokens %s and %s both assigned number %d"), - symbols[token_translations[this->user_token_number]]->tag, - this->tag, this->user_token_number); - - token_translations[this->user_token_number] = this->number; - } - - return TRUE; -} - - /*===================\ | Low level lexing. | \===================*/ @@ -547,7 +374,6 @@ copy_dollar (FILE *fin, struct obstack *oout, { read_type_name (fin); type_name = token_buffer; - value_components_used = 1; c = getc (fin); } @@ -657,14 +483,12 @@ copy_definition (struct obstack *oout) } -/*-------------------------------------------------------------------. -| Parse what comes after %token or %nterm. For %token, WHAT_IS is | -| token_sym and WHAT_IS_NOT is nterm_sym. For %nterm, the arguments | -| are reversed. | -`-------------------------------------------------------------------*/ +/*------------------------------------------. +| Parse what comes after %token or %nterm. | +`------------------------------------------*/ static void -parse_token_decl (symbol_class what_is, symbol_class what_is_not) +parse_token_decl (symbol_class class) { token_t token = tok_undef; char *typename = NULL; @@ -686,61 +510,40 @@ parse_token_decl (symbol_class what_is, symbol_class what_is_not) fatal (_("Premature EOF after %s"), token_buffer); token = lex (); - if (token == tok_comma) + switch (token) { + case tok_comma: symbol = NULL; - continue; - } - if (token == tok_typename) - { + break; + + case tok_typename: typename = xstrdup (token_buffer); - value_components_used = 1; symbol = NULL; - } - else if (token == tok_identifier && *symval->tag == '\"' && symbol) - { - symbol_make_alias (symbol, typename); - symbol = NULL; - } - else if (token == tok_identifier) - { - int oldclass = symval->class; - symbol = symval; - - if (symbol->class == what_is_not) - complain (_("symbol %s redefined"), symbol->tag); - symbol->class = what_is; - if (what_is == nterm_sym && oldclass != nterm_sym) - symbol->number = nvars++; - if (what_is == token_sym && symbol->number == NUMBER_UNDEFINED) - symbol->number = ntokens++; - - if (typename) + break; + + case tok_identifier: + if (*symval->tag == '\"' && symbol) { - if (symbol->type_name == NULL) - symbol->type_name = typename; - else if (strcmp (typename, symbol->type_name) != 0) - complain (_("type redeclaration for %s"), symbol->tag); + symbol_make_alias (symbol, symval, typename); + symbol = NULL; } - } - else if (symbol && token == tok_number) - { - symbol->user_token_number = numval; - /* User defined EOF token? */ - if (numval == 0) + else { - eoftoken = symbol; - eoftoken->number = 0; - /* It is always mapped to 0, so it was already counted in - NTOKENS. */ - --ntokens; + symbol = symval; + symbol_class_set (symbol, class); + if (typename) + symbol_type_set (symbol, typename); } - } - else - { + break; + + case tok_number: + symbol_user_token_number_set (symbol, numval); + break; + + default: complain (_("`%s' is invalid in %s"), token_buffer, - (what_is == token_sym) ? "%token" : "%nterm"); + (class == token_sym) ? "%token" : "%nterm"); skip_to_char ('%'); } } @@ -762,7 +565,7 @@ parse_start_decl (void) else { start_flag = 1; - startval = symval; + startsymbol = symval; } } @@ -799,17 +602,12 @@ parse_type_decl (void) switch (t) { - case tok_comma: case tok_semicolon: break; case tok_identifier: - if (symval->type_name == NULL) - symval->type_name = name; - else if (strcmp (name, symval->type_name) != 0) - complain (_("type redeclaration for %s"), symval->tag); - + symbol_type_set (symval, name); break; default: @@ -858,30 +656,16 @@ parse_assoc_decl (associativity assoc) break; case tok_identifier: - if (symval->prec != 0) - complain (_("redefining precedence of %s"), symval->tag); - symval->prec = lastprec; - symval->assoc = assoc; - if (symval->class == nterm_sym) - complain (_("symbol %s redefined"), symval->tag); - if (symval->number == NUMBER_UNDEFINED) - { - symval->number = ntokens++; - symval->class = token_sym; - } + symbol_class_set (symval, token_sym); + symbol_precedence_set (symval, lastprec, assoc); if (name) - { /* record the type, if one is specified */ - if (symval->type_name == NULL) - symval->type_name = name; - else if (strcmp (name, symval->type_name) != 0) - complain (_("type redeclaration for %s"), symval->tag); - } + symbol_type_set (symval, name); break; case tok_number: if (prev == tok_identifier) { - symval->user_token_number = numval; + symbol_user_token_number_set (symval, numval); } else { @@ -988,84 +772,6 @@ parse_expect_decl (void) } -/*-------------------------------------------------------------------. -| Parse what comes after %thong. the full syntax is | -| | -| %thong token number literal | -| | -| the or number may be omitted. The number specifies the | -| user_token_number. | -| | -| Two symbols are entered in the table, one for the token symbol and | -| one for the literal. Both are given the , if any, from the | -| declaration. The ->user_token_number of the first is | -| USER_NUMBER_ALIAS and the ->user_token_number of the second is set | -| to the number, if any, from the declaration. The two symbols are | -| linked via pointers in their ->alias fields. | -| | -| During OUTPUT_DEFINES_TABLE, the symbol is reported thereafter, | -| only the literal string is retained it is the literal string that | -| is output to yytname | -`-------------------------------------------------------------------*/ - -static void -parse_thong_decl (void) -{ - token_t token; - symbol_t *symbol; - char *typename = 0; - int usrtoknum = USER_NUMBER_UNDEFINED; - - token = lex (); /* fetch typename or first token */ - if (token == tok_typename) - { - typename = xstrdup (token_buffer); - value_components_used = 1; - token = lex (); /* fetch first token */ - } - - /* process first token */ - - if (token != tok_identifier) - { - complain (_("unrecognized item %s, expected an identifier"), - token_buffer); - skip_to_char ('%'); - return; - } - symval->class = token_sym; - symval->type_name = typename; - symval->user_token_number = USER_NUMBER_ALIAS; - symbol = symval; - - token = lex (); /* get number or literal string */ - - if (token == tok_number) - { - usrtoknum = numval; - token = lex (); /* okay, did number, now get literal */ - } - - /* process literal string token */ - - if (token != tok_identifier || *symval->tag != '\"') - { - complain (_("expected string constant instead of %s"), token_buffer); - skip_to_char ('%'); - return; - } - symval->class = token_sym; - symval->type_name = typename; - symval->user_token_number = usrtoknum; - - symval->alias = symbol; - symbol->alias = symval; - - /* symbol and symval combined are only one symbol. */ - nsyms--; -} - - static void parse_muscle_decl (void) { @@ -1188,11 +894,11 @@ read_declarations (void) break; case tok_token: - parse_token_decl (token_sym, nterm_sym); + parse_token_decl (token_sym); break; case tok_nterm: - parse_token_decl (nterm_sym, token_sym); + parse_token_decl (nterm_sym); break; case tok_type: @@ -1211,10 +917,6 @@ read_declarations (void) parse_expect_decl (); break; - case tok_thong: - parse_thong_decl (); - break; - case tok_left: parse_assoc_decl (left_assoc); break; @@ -1370,19 +1072,109 @@ gensym (void) | in the rules section. | `-------------------------------------------------------------------*/ +/* The (currently) last symbol of GRAMMAR. */ +symbol_list *grammar_end = NULL; + +/* Append S to the GRAMMAR. */ +static void +grammar_symbol_append (symbol_t *s) +{ + symbol_list *p = symbol_list_new (s); + + if (grammar_end) + grammar_end->next = p; + else + grammar = p; + + grammar_end = p; +} + +/* The rule currently being defined, and the previous rule. Point to + the first symbol of each list: their lhs. */ +symbol_list *current_rule = NULL; +symbol_list *previous_rule = NULL; + + +/* Create a new rule for LHS in to the GRAMMAR. */ + +static void +grammar_rule_begin (symbol_t *lhs) +{ + if (!start_flag) + { + startsymbol = lhs; + start_flag = 1; + } + + /* Start a new rule and record its lhs. */ + ++nrules; + ++nritems; + + previous_rule = grammar_end; + grammar_symbol_append (lhs); + current_rule = grammar_end; + + /* Mark the rule's lhs as a nonterminal if not already so. */ + + if (lhs->class == unknown_sym) + { + lhs->class = nterm_sym; + lhs->number = nvars; + ++nvars; + } + else if (lhs->class == token_sym) + complain (_("rule given for %s, which is a token"), lhs->tag); +} + +/* The previous action turns out the be a mid-rule action. Attach it + to the current rule, i.e., create a dummy symbol, attach it this + mid-rule action, and append this dummy nonterminal to the current + rule. */ + +static void +grammar_midrule_action (void) +{ + /* Since the action was written out with this rule's number, we must + give the new rule this number by inserting the new rule before + it. */ + + /* Make a dummy nonterminal, a gensym. */ + symbol_t *sdummy = gensym (); + symbol_list *midrule_action = symbol_list_new (sdummy); + + /* Make a new rule, whose body is empty, before the current one, so + that the action just read can belong to it. */ + ++nrules; + ++nritems; + /* Attach its lineno to that of the host rule. */ + midrule_action->line = current_rule->line; + /* Move the action from the host rule to this one. */ + midrule_action->action = current_rule->action; + midrule_action->action_line = current_rule->action_line; + current_rule->action = NULL; + + if (previous_rule) + previous_rule->next = midrule_action; + else + grammar = midrule_action; + + /* End of the rule. */ + previous_rule = symbol_list_new (NULL); + previous_rule->next = current_rule; + + midrule_action->next = previous_rule; + + /* Insert the dummy generated by that rule into this rule. */ + ++nritems; + grammar_symbol_append (sdummy); +} + + static void readgram (void) { token_t t; symbol_t *lhs = NULL; - symbol_list *p = NULL; - symbol_list *p1 = NULL; - - /* Points to first symbol_list of current rule. its symbol is the - lhs of the rule. */ - symbol_list *crule = NULL; - /* Points to the symbol_list preceding crule. */ - symbol_list *crule1 = NULL; t = lex (); @@ -1399,12 +1191,6 @@ readgram (void) { lhs = symval; - if (!start_flag) - { - startval = lhs; - start_flag = 1; - } - t = lex (); if (t != tok_colon) { @@ -1412,39 +1198,13 @@ readgram (void) unlex (t); } } - if (nrules == 0 && t == tok_bar) { complain (_("grammar starts with vertical bar")); lhs = symval; /* BOGUS: use a random symval */ } - /* start a new rule and record its lhs. */ - - ++nrules; - ++nritems; - - p = symbol_list_new (lhs); - - crule1 = p1; - if (p1) - p1->next = p; - else - grammar = p; - - p1 = p; - crule = p; - - /* mark the rule's lhs as a nonterminal if not already so. */ - - if (lhs->class == unknown_sym) - { - lhs->class = nterm_sym; - lhs->number = nvars; - ++nvars; - } - else if (lhs->class == token_sym) - complain (_("rule given for %s, which is a token"), lhs->tag); + grammar_rule_begin (lhs); /* read the rhs of the rule. */ for (;;) @@ -1453,7 +1213,7 @@ readgram (void) if (t == tok_prec) { t = lex (); - crule->ruleprec = symval; + current_rule->ruleprec = symval; t = lex (); } @@ -1488,56 +1248,18 @@ readgram (void) non-terminal. */ if (action_flag) { - /* Since the action was written out with this rule's - number, we must give the new rule this number by - inserting the new rule before it. */ - - /* Make a dummy nonterminal, a gensym. */ - symbol_t *sdummy = gensym (); - - /* Make a new rule, whose body is empty, before the - current one, so that the action just read can - belong to it. */ - ++nrules; - ++nritems; - p = symbol_list_new (sdummy); - /* Attach its lineno to that of the host rule. */ - p->line = crule->line; - /* Move the action from the host rule to this one. */ - p->action = crule->action; - p->action_line = crule->action_line; - crule->action = NULL; - - if (crule1) - crule1->next = p; - else - grammar = p; - /* End of the rule. */ - crule1 = symbol_list_new (NULL); - crule1->next = crule; - - p->next = crule1; - - /* Insert the dummy generated by that rule into this - rule. */ - ++nritems; - p = symbol_list_new (sdummy); - p1->next = p; - p1 = p; - + grammar_midrule_action (); action_flag = 0; } if (t == tok_identifier) { ++nritems; - p = symbol_list_new (symval); - p1->next = p; - p1 = p; + grammar_symbol_append (symval); } else /* handle an action. */ { - parse_action (crule, rulelength); + parse_action (current_rule, rulelength); action_flag = 1; ++xactions; /* JF */ } @@ -1545,15 +1267,13 @@ readgram (void) } /* end of read rhs of rule */ /* Put an empty link in the list to mark the end of this rule */ - p = symbol_list_new (NULL); - p1->next = p; - p1 = p; + grammar_symbol_append (NULL); if (t == tok_prec) { complain (_("two @prec's in a row")); t = lex (); - crule->ruleprec = symval; + current_rule->ruleprec = symval; t = lex (); } @@ -1562,7 +1282,7 @@ readgram (void) /* This case never occurs -wjh */ if (action_flag) complain (_("two actions at end of one rule")); - parse_action (crule, rulelength); + parse_action (current_rule, rulelength); action_flag = 1; ++xactions; /* -wjh */ t = lex (); @@ -1599,22 +1319,23 @@ readgram (void) fatal (_("no rules in the input grammar")); /* Report any undefined symbols and consider them nonterminals. */ - symbols_do (symbol_check_defined, NULL); + symbols_check_defined (); /* Insert the initial rule, which line is that of the first rule (not that of the start symbol): axiom: %start EOF. */ - p = symbol_list_new (axiom); - p->line = grammar->line; - p->next = symbol_list_new (startval); - p->next->next = symbol_list_new (eoftoken); - p->next->next->next = symbol_list_new (NULL); - p->next->next->next->next = grammar; - nrules += 1; - nritems += 3; - grammar = p; - startval = axiom; + { + symbol_list *p = symbol_list_new (axiom); + p->line = grammar->line; + p->next = symbol_list_new (startsymbol); + p->next->next = symbol_list_new (eoftoken); + p->next->next->next = symbol_list_new (NULL); + p->next->next->next->next = grammar; + nrules += 1; + nritems += 3; + grammar = p; + } if (nsyms > SHRT_MAX) fatal (_("too many symbols (tokens plus nonterminals); maximum %d"), @@ -1649,85 +1370,6 @@ read_additionnal_code (void) } -/*------------------------------------------------------------------. -| Set TOKEN_TRANSLATIONS. Check that no two symbols share the same | -| number. | -`------------------------------------------------------------------*/ - -static void -token_translations_init (void) -{ - int num_256_available_p = TRUE; - int i; - - /* Find the highest user token number, and whether 256, the POSIX - preferred user token number for the error token, is used. */ - max_user_token_number = 0; - for (i = 0; i < ntokens; ++i) - { - symbol_t *this = symbols[i]; - if (this->user_token_number != USER_NUMBER_UNDEFINED) - { - if (this->user_token_number > max_user_token_number) - max_user_token_number = this->user_token_number; - if (this->user_token_number == 256) - num_256_available_p = FALSE; - } - } - - /* If 256 is not used, assign it to error, to follow POSIX. */ - if (num_256_available_p - && errtoken->user_token_number == USER_NUMBER_UNDEFINED) - errtoken->user_token_number = 256; - - /* Set the missing user numbers. */ - if (max_user_token_number < 256) - max_user_token_number = 256; - - for (i = 0; i < ntokens; ++i) - { - symbol_t *this = symbols[i]; - if (this->user_token_number == USER_NUMBER_UNDEFINED) - this->user_token_number = ++max_user_token_number; - if (this->user_token_number > max_user_token_number) - max_user_token_number = this->user_token_number; - } - - token_translations = XCALLOC (token_number_t, max_user_token_number + 1); - - /* Initialize all entries for literal tokens to 2, the internal - token number for $undefined., which represents all invalid - inputs. */ - for (i = 0; i < max_user_token_number + 1; i++) - token_translations[i] = undeftoken->number; - symbols_do (symbol_translation, NULL); -} - - -/*----------------------------------------------------------------. -| Assign symbol numbers, and write definition of token names into | -| FDEFINES. Set up vectors SYMBOL_TABLE, TAGS of symbols. | -`----------------------------------------------------------------*/ - -static void -packsymbols (void) -{ - symbols = XCALLOC (symbol_t *, nsyms); - - symbols_do (symbol_check_alias_consistence, NULL); - symbols_do (symbol_pack, NULL); - - token_translations_init (); - - if (startval->class == unknown_sym) - fatal (_("the start symbol %s is undefined"), startval->tag); - else if (startval->class == token_sym) - fatal (_("the start symbol %s is a token"), startval->tag); - - start_symbol = startval->number; -} - - /*---------------------------------------------------------------. | Convert the rules into the representation using RRHS, RLHS and | | RITEM. | @@ -1762,9 +1404,9 @@ packgram (void) p = p->next; while (p && p->sym) { - /* item_number_t = token_number_t. + /* item_number_t = symbol_number_t. But the former needs to contain more: negative rule numbers. */ - ritem[itemno++] = token_number_as_item_number (p->sym->number); + ritem[itemno++] = symbol_number_as_item_number (p->sym->number); /* A rule gets by default the precedence and associativity of the last token in it. */ if (p->sym->class == token_sym) @@ -1862,7 +1504,7 @@ reader (void) /* Assign the symbols their symbol numbers. Write #defines for the token symbols into FDEFINES if requested. */ - packsymbols (); + symbols_pack (); /* Convert the grammar into the format described in gram.h. */ packgram ();