X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/9bc0dd679f19b79f7250d2b16563b590a3b032bb..405d53b7248b3142841cc0bae60b21b79721f4e4:/src/reader.c diff --git a/src/reader.c b/src/reader.c index 8d2c668c..d5cd629f 100644 --- a/src/reader.c +++ b/src/reader.c @@ -22,7 +22,6 @@ #include #include "system.h" -#include #include @@ -44,10 +43,11 @@ static symbol_list *grammar = NULL; static bool start_flag = false; merger_list *merge_functions; -/* Was %union, %before-definitions, or %after-definitions seen? */ -bool typed = false; -bool before_definitions = false; -bool after_definitions = false; +/* Was %union seen? */ +bool union_seen = false; + +/* Was a tag seen? */ +bool tag_seen = false; /* Should rules have a default precedence? */ bool default_prec = true; @@ -70,17 +70,16 @@ grammar_start_symbol_set (symbol *sym, location loc) } -/*---------------------------------------------------------------------------. -| There are two prologues: one before the first %union, %before-definitions, | -| or %after-definitions; and one after. Augment the current one. | -`---------------------------------------------------------------------------*/ +/*---------------------------------------------------------------------. +| There are two prologues: one before the first %union and one after. | +| Augment the one specified by POST. | +`---------------------------------------------------------------------*/ void -prologue_augment (const char *prologue, location loc) +prologue_augment (const char *prologue, location loc, bool post) { struct obstack *oout = - !(typed || before_definitions || after_definitions) - ? &pre_prologue_obstack : &post_prologue_obstack; + !post ? &pre_prologue_obstack : &post_prologue_obstack; obstack_fgrow1 (oout, "]b4_syncline(%d, [[", loc.start.line); /* FIXME: Protection of M4 characters missing here. See @@ -93,14 +92,13 @@ prologue_augment (const char *prologue, location loc) -/*-------------------------------------------------------------------. -| Return the merger index for a merging function named NAME, whose | -| arguments have type TYPE. Records the function, if new, in | -| MERGER_LIST. | -`-------------------------------------------------------------------*/ +/*------------------------------------------------------------------------. +| Return the merger index for a merging function named NAME. Records the | +| function, if new, in MERGER_LIST. | +`------------------------------------------------------------------------*/ static int -get_merge_function (uniqstr name, uniqstr type, location loc) +get_merge_function (uniqstr name) { merger_list *syms; merger_list head; @@ -109,9 +107,6 @@ get_merge_function (uniqstr name, uniqstr type, location loc) if (! glr_parser) return 0; - if (type == NULL) - type = uniqstr_new (""); - head.next = merge_functions; for (syms = &head, n = 1; syms->next; syms = syms->next, n += 1) if (UNIQSTR_EQ (name, syms->next->name)) @@ -120,16 +115,51 @@ get_merge_function (uniqstr name, uniqstr type, location loc) { syms->next = xmalloc (sizeof syms->next[0]); syms->next->name = uniqstr_new (name); - syms->next->type = uniqstr_new (type); + /* After all symbol type declarations have been parsed, packgram invokes + record_merge_function_type to set the type. */ + syms->next->type = NULL; syms->next->next = NULL; merge_functions = head.next; } - else if (!UNIQSTR_EQ (type, syms->next->type)) - warn_at (loc, _("result type clash on merge function %s: <%s> != <%s>"), - name, type, syms->next->type); return n; } +/*-------------------------------------------------------------------------. +| For the existing merging function with index MERGER, record the result | +| type as TYPE as required by the lhs of the rule whose %merge declaration | +| is at DECLARATION_LOC. | +`-------------------------------------------------------------------------*/ + +static void +record_merge_function_type (int merger, uniqstr type, location declaration_loc) +{ + int merger_find; + merger_list *merge_function; + + if (merger <= 0) + return; + + if (type == NULL) + type = uniqstr_new (""); + + merger_find = 1; + for (merge_function = merge_functions; + merge_function != NULL && merger_find != merger; + merge_function = merge_function->next) + merger_find += 1; + aver (merge_function != NULL && merger_find == merger); + if (merge_function->type != NULL && !UNIQSTR_EQ (merge_function->type, type)) + { + complain_at (declaration_loc, + _("result type clash on merge function `%s': <%s> != <%s>"), + merge_function->name, type, merge_function->type); + complain_at (merge_function->type_declaration_location, + _("previous declaration")); + } + merge_function->type = uniqstr_new (type); + merge_function->type_declaration_location = declaration_loc; +} + /*--------------------------------------. | Free all merge-function definitions. | `--------------------------------------*/ @@ -165,7 +195,7 @@ static symbol_list *grammar_end = NULL; static void grammar_symbol_append (symbol *sym, location loc) { - symbol_list *p = symbol_list_new (sym, loc); + symbol_list *p = symbol_list_sym_new (sym, loc); if (grammar_end) grammar_end->next = p; @@ -183,7 +213,7 @@ grammar_symbol_append (symbol *sym, location loc) /* The rule currently being defined, and the previous rule. CURRENT_RULE points to the first LHS of the current rule, while PREVIOUS_RULE_END points to the *end* of the previous rule (NULL). */ -symbol_list *current_rule = NULL; +static symbol_list *current_rule = NULL; static symbol_list *previous_rule_end = NULL; @@ -194,13 +224,6 @@ static symbol_list *previous_rule_end = NULL; void grammar_current_rule_begin (symbol *lhs, location loc) { - if (!start_flag) - { - startsymbol = lhs; - startsymbol_location = loc; - start_flag = true; - } - /* Start a new rule and record its lhs. */ ++nrules; previous_rule_end = grammar_end; @@ -220,16 +243,24 @@ grammar_current_rule_begin (symbol *lhs, location loc) /*----------------------------------------------------------------------. -| A symbol should be used if it has a destructor, or if it is a | -| mid-rule symbol (i.e., the generated LHS replacing a mid-rule | -| action) that was assigned to, as in "exp: { $$ = 1; } { $$ = $1; }". | +| A symbol should be used if either: | +| 1. It has a destructor. | +| 2. --warnings=midrule-values and the symbol is a mid-rule symbol | +| (i.e., the generated LHS replacing a mid-rule action) that was | +| assigned to or used, as in "exp: { $$ = 1; } { $$ = $1; }". | `----------------------------------------------------------------------*/ static bool symbol_should_be_used (symbol_list const *s) { - return (s->sym->destructor - || (s->midrule && s->midrule->used)); + if (symbol_destructor_get (s->content.sym)) + return true; + if (warnings_flag & warnings_midrule_values) + return ((s->midrule && s->midrule->used) + || (s->midrule_parent_rule + && symbol_list_n_get (s->midrule_parent_rule, + s->midrule_parent_rhs_index)->used)); + return false; } /*----------------------------------------------------------------. @@ -247,13 +278,13 @@ grammar_rule_check (const symbol_list *r) Don't worry about the default action if $$ is untyped, since $$'s value can't be used. */ - if (!r->action && r->sym->type_name) + if (!r->action && r->content.sym->type_name) { - symbol *first_rhs = r->next->sym; + symbol *first_rhs = r->next->content.sym; /* If $$ is being set in default way, report if any type mismatch. */ if (first_rhs) { - char const *lhs_type = r->sym->type_name; + char const *lhs_type = r->content.sym->type_name; const char *rhs_type = first_rhs->type_name ? first_rhs->type_name : ""; if (!UNIQSTR_EQ (lhs_type, rhs_type)) @@ -271,7 +302,7 @@ grammar_rule_check (const symbol_list *r) { symbol_list const *l = r; int n = 0; - for (; l && l->sym; l = l->next, ++n) + for (; l && l->content.sym; l = l->next, ++n) if (! (l->used || !symbol_should_be_used (l) /* The default action, $$ = $1, `uses' both. */ @@ -296,7 +327,6 @@ grammar_current_rule_end (location loc) /* Put an empty link in the list to mark the end of this rule */ grammar_symbol_append (NULL, grammar_end->location); current_rule->location = loc; - grammar_rule_check (current_rule); } @@ -318,7 +348,7 @@ grammar_midrule_action (void) action. Create the MIDRULE. */ location dummy_location = current_rule->action_location; symbol *dummy = dummy_symbol_get (dummy_location); - symbol_list *midrule = symbol_list_new (dummy, dummy_location); + symbol_list *midrule = symbol_list_sym_new (dummy, dummy_location); /* Make a new rule, whose body is empty, before the current one, so that the action just read can belong to it. */ @@ -329,10 +359,9 @@ grammar_midrule_action (void) midrule->action = current_rule->action; midrule->action_location = dummy_location; current_rule->action = NULL; - /* If $$ was used in the action, the LHS of the enclosing rule was - incorrectly flagged as used. */ - midrule->used = current_rule->used; - current_rule->used = false; + /* The action has not been translated yet, so $$ use hasn't been + detected yet. */ + midrule->used = false; if (previous_rule_end) previous_rule_end->next = midrule; @@ -340,8 +369,7 @@ grammar_midrule_action (void) grammar = midrule; /* End the dummy's rule. */ - midrule->next = symbol_list_new (NULL, dummy_location); - grammar_rule_check (midrule); + midrule->next = symbol_list_sym_new (NULL, dummy_location); midrule->next->next = current_rule; previous_rule_end = midrule->next; @@ -350,6 +378,8 @@ grammar_midrule_action (void) the current rule. Bind it to its dedicated rule. */ grammar_current_rule_symbol_append (dummy, dummy_location); grammar_end->midrule = midrule; + midrule->midrule_parent_rule = current_rule; + midrule->midrule_parent_rhs_index = symbol_list_length (current_rule->next); } /* Set the precedence symbol of the current rule to PRECSYM. */ @@ -386,8 +416,8 @@ grammar_current_rule_merge_set (uniqstr name, location loc) warn_at (loc, _("%s affects only GLR parsers"), "%merge"); if (current_rule->merger != 0) complain_at (loc, _("only one %s allowed per rule"), "%merge"); - current_rule->merger = - get_merge_function (name, current_rule->sym->type_name, loc); + current_rule->merger = get_merge_function (name); + current_rule->merger_declaration_location = loc; } /* Attach SYM to the current rule. If needed, move the previous @@ -406,7 +436,11 @@ grammar_current_rule_symbol_append (symbol *sym, location loc) void grammar_current_rule_action_append (const char *action, location loc) { - current_rule->action = translate_rule_action (current_rule, action, loc); + if (current_rule->action) + grammar_midrule_action (); + /* After all symbol declarations have been parsed, packgram invokes + translate_rule_action. */ + current_rule->action = action; current_rule->action_location = loc; } @@ -430,13 +464,30 @@ packgram (void) rules = xnmalloc (nrules, sizeof *rules); + /* Before invoking grammar_rule_check on any rule, make sure all actions have + already been scanned in order to set `used' flags. Otherwise, checking + that a midrule's $$ should be set will not always work properly because + the check must forward-reference the midrule's parent rule. For the same + reason, all the `used' flags must be set before checking whether to remove + `$' from any midrule symbol name. */ + while (p) + { + if (p->action) + p->action = translate_rule_action (p); + if (p) + p = p->next; + } + + p = grammar; while (p) { int rule_length = 0; symbol *ruleprec = p->ruleprec; + record_merge_function_type (p->merger, p->content.sym->type_name, + p->merger_declaration_location); rules[ruleno].user_number = ruleno; rules[ruleno].number = ruleno; - rules[ruleno].lhs = p->sym; + rules[ruleno].lhs = p->content.sym; rules[ruleno].rhs = ritem + itemno; rules[ruleno].prec = NULL; rules[ruleno].dprec = p->dprec; @@ -447,7 +498,22 @@ packgram (void) rules[ruleno].action = p->action; rules[ruleno].action_location = p->action_location; - for (p = p->next; p && p->sym; p = p->next) + /* If the midrule's $$ is set or its $n is used, remove the `$' from the + symbol name so that it's a user-defined symbol so that the default + %destructor and %printer apply. */ + if (p->midrule_parent_rule + && (p->used + || symbol_list_n_get (p->midrule_parent_rule, + p->midrule_parent_rhs_index)->used)) + p->content.sym->tag += 1; + + /* Don't check the generated rule 0. It has no action, so some rhs + symbols may appear unused, but the parsing algorithm ensures that + %destructor's are invoked appropriately. */ + if (p != grammar) + grammar_rule_check (p); + + for (p = p->next; p && p->content.sym; p = p->next) { ++rule_length; @@ -458,11 +524,12 @@ packgram (void) /* item_number = symbol_number. But the former needs to contain more: negative rule numbers. */ - ritem[itemno++] = symbol_number_as_item_number (p->sym->number); + ritem[itemno++] = + symbol_number_as_item_number (p->content.sym->number); /* A rule gets by default the precedence and associativity of its last token. */ - if (p->sym->class == token_sym && default_prec) - rules[ruleno].prec = p->sym; + if (p->content.sym->class == token_sym && default_prec) + rules[ruleno].prec = p->content.sym; } /* If this rule has a %prec, @@ -474,15 +541,15 @@ packgram (void) } /* An item ends by the rule number (negated). */ ritem[itemno++] = rule_number_as_item_number (ruleno); - assert (itemno < ITEM_NUMBER_MAX); + aver (itemno < ITEM_NUMBER_MAX); ++ruleno; - assert (ruleno < RULE_NUMBER_MAX); + aver (ruleno < RULE_NUMBER_MAX); if (p) p = p->next; } - assert (itemno == nritems); + aver (itemno == nritems); if (trace_flag & trace_sets) ritem_print (stderr); @@ -560,23 +627,41 @@ check_and_convert_grammar (void) endtoken->user_token_number = 0; } + /* Find the start symbol if no %start. */ + if (!start_flag) + { + symbol_list *node; + for (node = grammar; + node != NULL && symbol_is_dummy (node->content.sym); + node = node->next) + { + for (node = node->next; + node != NULL && node->content.sym != NULL; + node = node->next) + ; + } + aver (node != NULL); + grammar_start_symbol_set (node->content.sym, + node->content.sym->location); + } + /* Insert the initial rule, whose line is that of the first rule (not that of the start symbol): accept: %start EOF. */ { - symbol_list *p = symbol_list_new (accept, empty_location); + symbol_list *p = symbol_list_sym_new (accept, empty_location); p->location = grammar->location; - p->next = symbol_list_new (startsymbol, empty_location); - p->next->next = symbol_list_new (endtoken, empty_location); - p->next->next->next = symbol_list_new (NULL, empty_location); + p->next = symbol_list_sym_new (startsymbol, empty_location); + p->next->next = symbol_list_sym_new (endtoken, empty_location); + p->next->next->next = symbol_list_sym_new (NULL, empty_location); p->next->next->next->next = grammar; nrules += 1; nritems += 3; grammar = p; } - assert (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars); + aver (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars); /* Assign the symbols their symbol numbers. Write #defines for the token symbols into FDEFINES if requested. */ @@ -586,5 +671,5 @@ check_and_convert_grammar (void) packgram (); /* The grammar as a symbol_list is no longer needed. */ - LIST_FREE (symbol_list, grammar); + symbol_list_free (grammar); }