/* Bison Action Scanner -*- C -*- Copyright (C) 2006, 2007, 2008-2009 Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. This program 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 3 of the License, or (at your option) any later version. This program 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 this program. If not, see . */ %option debug nodefault noinput nounput noyywrap never-interactive %option prefix="code_" outfile="lex.yy.c" %{ /* Work around a bug in flex 2.5.31. See Debian bug 333231 . */ #undef code_wrap #define code_wrap() 1 #define FLEX_PREFIX(Id) code_ ## Id #include "flex-scanner.h" #include "complain.h" #include "reader.h" #include "getargs.h" #include "scan-code.h" #include "symlist.h" #include #include #include /* The current calling start condition: SC_RULE_ACTION or SC_SYMBOL_ACTION. */ # define YY_DECL static char *code_lex (code_props *self, int sc_context) YY_DECL; #define YY_USER_ACTION location_compute (loc, &loc->end, yytext, yyleng); static void handle_action_dollar (symbol_list *rule, char *cp, location dollar_loc); static void handle_action_at (symbol_list *rule, char *cp, location at_loc); /* A string to be pushed to obstack after dollar/at has been handled. */ static char *ref_tail_fields; static location the_location; static location *loc = &the_location; /* A string representing the most recent translation. */ static char *last_string; /* True if an untyped $$ or $n was seen. */ static bool untyped_var_seen; %} /* C and C++ comments in code. */ %x SC_COMMENT SC_LINE_COMMENT /* Strings and characters in code. */ %x SC_STRING SC_CHARACTER /* Whether in a rule or symbol action. Specifies the translation of $ and @. */ %x SC_RULE_ACTION SC_SYMBOL_ACTION /* POSIX says that a tag must be both an id and a C union member, but historically almost any character is allowed in a tag. We disallow NUL and newline, as this simplifies our implementation. */ tag [^\0\n>]+ /* Zero or more instances of backslash-newline. Following GCC, allow white space between the backslash and the newline. */ splice (\\[ \f\t\v]*\n)* /* C style identifier. Must start with letter. Will be used for named symbol references. Shall be kept synchronized with scan-gram.l "letter" and "id". */ letter [-.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_] id {letter}({letter}|[0-9])* ref -?[0-9]+|{id}|"["{id}"]"|"$" %% %{ /* Nesting level of the current code in braces. */ int braces_level = 0; /* Whether a semicolon is probably needed. The heuristic is that a semicolon is not needed after `{', `}', `;', or a C preprocessor directive, and that whitespaces and comments do not affect this flag. Note that `{' does not need a semicolon because of `{}'. A semicolon may be needed before a cpp direcive, but don't bother. */ bool need_semicolon = false; /* Whether in a C preprocessor directive. Don't use a start condition for this because, at the end of strings and comments, we still need to know whether we're in a directive. */ bool in_cpp = false; /* This scanner is special: it is invoked only once, henceforth is expected to return only once. This initialization is therefore done once per action to translate. */ aver (sc_context == SC_SYMBOL_ACTION || sc_context == SC_RULE_ACTION || sc_context == INITIAL); BEGIN sc_context; %} /*------------------------------------------------------------. | Scanning a C comment. The initial `/ *' is already eaten. | `------------------------------------------------------------*/ { "*"{splice}"/" STRING_GROW; BEGIN sc_context; } /*--------------------------------------------------------------. | Scanning a line comment. The initial `//' is already eaten. | `--------------------------------------------------------------*/ { "\n" STRING_GROW; BEGIN sc_context; {splice} STRING_GROW; } /*--------------------------------------------. | Scanning user-code characters and strings. | `--------------------------------------------*/ { {splice}|\\{splice}. STRING_GROW; } { "'" STRING_GROW; BEGIN sc_context; } { "\"" STRING_GROW; BEGIN sc_context; } { "'" { STRING_GROW; BEGIN SC_CHARACTER; need_semicolon = true; } "\"" { STRING_GROW; BEGIN SC_STRING; need_semicolon = true; } "/"{splice}"*" { STRING_GROW; BEGIN SC_COMMENT; } "/"{splice}"/" { STRING_GROW; BEGIN SC_LINE_COMMENT; } } { "$"("<"{tag}">")?{ref} { ref_tail_fields = 0; handle_action_dollar (self->rule, yytext, *loc); if (ref_tail_fields) { obstack_sgrow (&obstack_for_string, ref_tail_fields); } need_semicolon = true; } "@"{ref} { ref_tail_fields = 0; handle_action_at (self->rule, yytext, *loc); if (ref_tail_fields) { obstack_sgrow (&obstack_for_string, ref_tail_fields); } need_semicolon = true; } "$" { warn_at (*loc, _("stray `$'")); obstack_sgrow (&obstack_for_string, "$]["); need_semicolon = true; } "@" { warn_at (*loc, _("stray `@'")); obstack_sgrow (&obstack_for_string, "@@"); need_semicolon = true; } "[" { obstack_sgrow (&obstack_for_string, "@{"); need_semicolon = true; } "]" { obstack_sgrow (&obstack_for_string, "@}"); need_semicolon = true; } ";" STRING_GROW; need_semicolon = false; "{" STRING_GROW; ++braces_level; need_semicolon = false; "}" { bool outer_brace = --braces_level == 0; /* As an undocumented Bison extension, append `;' before the last brace in braced code, so that the user code can omit trailing `;'. But do not append `;' if emulating Yacc, since Yacc does not append one. */ if (outer_brace && !yacc_flag && language_prio == default_prio && skeleton_prio == default_prio && need_semicolon && ! in_cpp) { warn_at (*loc, _("a `;' might be needed at the end of action code")); warn_at (*loc, _("future versions of Bison will not add the `;'")); obstack_1grow (&obstack_for_string, ';'); } STRING_GROW; need_semicolon = false; } /* Preprocessing directives should only be recognized at the beginning of lines, allowing whitespace including comments, but in C/C++, `#' can only be the start of preprocessor directives or within `#define' directives anyway, so don't bother with begin of line. */ "#" STRING_GROW; in_cpp = true; {splice} STRING_GROW; [\n\r] STRING_GROW; if (in_cpp) in_cpp = need_semicolon = false; [ \t\f] STRING_GROW; . STRING_GROW; need_semicolon = true; } { "$$" { obstack_sgrow (&obstack_for_string, "]b4_dollar_dollar["); self->is_value_used = true; } "@$" { obstack_sgrow (&obstack_for_string, "]b4_at_dollar["); locations_flag = true; } } /*-----------------------------------------. | Escape M4 quoting characters in C code. | `-----------------------------------------*/ <*> { \$ obstack_sgrow (&obstack_for_string, "$]["); \@ obstack_sgrow (&obstack_for_string, "@@"); \[ obstack_sgrow (&obstack_for_string, "@{"); \] obstack_sgrow (&obstack_for_string, "@}"); } /*-----------------------------------------------------. | By default, grow the string obstack with the input. | `-----------------------------------------------------*/ <*>.|\n STRING_GROW; /* End of processing. */ <*><> { STRING_FINISH; return last_string; } %% static inline bool is_dot_or_dash (char ch) { return ch == '.' || ch == '-'; } static inline bool contains_dot_or_dash (const char* p) { for (; *p; ++p) if (is_dot_or_dash (*p)) return true; return false; } /* Defines a variant of a symbolic name resolution. */ typedef struct { /* Index in symbol list. */ unsigned symbol_index; /* Matched symbol id and loc. */ uniqstr id; location loc; /* Hiding named reference. */ named_ref* hidden_by; /* Error flags. May contain zero (no errors) or a combination of VARIANT_* values. */ unsigned err; } variant; /* Set when the variant refers to a symbol hidden by an explicit symbol reference. */ #define VARIANT_HIDDEN (1 << 0) /* Set when the variant refers to a symbol containing dots or dashes. Will require explicit bracketing. */ #define VARIANT_BAD_BRACKETING (1 << 1) /* Set when the variant refers to a symbol which is not visible from current midrule. */ #define VARIANT_NOT_VISIBLE_FROM_MIDRULE (1 << 2) static variant *variant_table = 0; static unsigned variant_table_size = 0; static unsigned variant_count = 0; static variant * variant_table_grow (void) { ++variant_count; if (variant_count > variant_table_size) { while (variant_count > variant_table_size) variant_table_size = 2 * variant_table_size + 3; variant_table = xnrealloc (variant_table, variant_table_size, sizeof *variant_table); } return &variant_table[variant_count - 1]; } static void variant_table_free (void) { free (variant_table); variant_table = 0; variant_table_size = variant_count = 0; } static char * find_prefix_end (const char *prefix, char *begin, char *end) { char *ptr = begin; for (; *prefix && ptr != end; ++prefix, ++ptr) if (*prefix != *ptr) return 0; if (*prefix) return 0; return ptr; } static variant * variant_add (uniqstr id, location id_loc, unsigned symbol_index, char *cp, char *cp_end, bool exact_mode) { char *prefix_end; prefix_end = find_prefix_end (id, cp, cp_end); if (prefix_end && (prefix_end == cp_end || (!exact_mode && is_dot_or_dash (*prefix_end)))) { variant *r = variant_table_grow (); r->symbol_index = symbol_index; r->id = id; r->loc = id_loc; r->hidden_by = NULL; r->err = 0; return r; } else return NULL; } static const char * get_at_spec(unsigned symbol_index) { static char at_buf[20]; if (symbol_index == 0) strcpy (at_buf, "$$"); else snprintf (at_buf, sizeof at_buf, "$%u", symbol_index); return at_buf; } static void show_sub_messages (const char* cp, bool exact_mode, int midrule_rhs_index, char dollar_or_at, bool is_warning) { unsigned i; for (i = 0; i < variant_count; ++i) { const variant *var = &variant_table[i]; const char *at_spec = get_at_spec (var->symbol_index); if (var->err == 0) { if (is_warning) warn_at (var->loc, _(" refers to: %c%s at %s"), dollar_or_at, var->id, at_spec); else complain_at (var->loc, _(" refers to: %c%s at %s"), dollar_or_at, var->id, at_spec); } else { static struct obstack msg_buf; const char *tail = exact_mode ? "" : cp + strlen (var->id); const char *id = var->hidden_by ? var->hidden_by->id : var->id; location id_loc = var->hidden_by ? var->hidden_by->loc : var->loc; /* Create the explanation message. */ obstack_init (&msg_buf); obstack_fgrow1 (&msg_buf, " possibly meant: %c", dollar_or_at); if (contains_dot_or_dash (id)) obstack_fgrow1 (&msg_buf, "[%s]", id); else obstack_sgrow (&msg_buf, id); obstack_sgrow (&msg_buf, tail); if (var->err & VARIANT_HIDDEN) { obstack_fgrow1 (&msg_buf, ", hiding %c", dollar_or_at); if (contains_dot_or_dash (var->id)) obstack_fgrow1 (&msg_buf, "[%s]", var->id); else obstack_sgrow (&msg_buf, var->id); obstack_sgrow (&msg_buf, tail); } obstack_fgrow1 (&msg_buf, " at %s", at_spec); if (var->err & VARIANT_NOT_VISIBLE_FROM_MIDRULE) obstack_fgrow1 (&msg_buf, ", cannot be accessed from " "mid-rule action at $%d", midrule_rhs_index); obstack_1grow (&msg_buf, '\0'); if (is_warning) warn_at (id_loc, _("%s"), (char *) obstack_finish (&msg_buf)); else complain_at (id_loc, _("%s"), (char *) obstack_finish (&msg_buf)); obstack_free (&msg_buf, 0); } } } /* Returned from "parse_ref" when the reference is inappropriate. */ #define INVALID_REF (INT_MIN) /* Returned from "parse_ref" when the reference points to LHS ($$) of the current rule or midrule. */ #define LHS_REF (INT_MIN + 1) /* Parse named or positional reference. In case of positional references, can return negative values for $-n "deep" stack accesses. */ static long int parse_ref (char *cp, symbol_list *rule, int rule_length, int midrule_rhs_index, char *text, location text_loc, char dollar_or_at) { symbol_list *l; char *cp_end; bool exact_mode; unsigned i; unsigned valid_variants = 0; unsigned valid_variant_index = 0; if ('$' == *cp) return LHS_REF; if (c_isdigit (*cp) || (*cp == '-' && c_isdigit (* (cp + 1)))) { long int num = strtol (cp, &cp, 10); if (1 - INT_MAX + rule_length <= num && num <= rule_length) return num; else { complain_at (text_loc, _("integer out of range: %s"), quote (text)); return INVALID_REF; } } if ('[' == *cp) { /* Ignore the brackets. */ char *p; for (p = ++cp; *p != ']'; ++p) continue; cp_end = p; exact_mode = true; } else { /* Take all characters of the name. */ char* p; for (p = cp; *p; ++p) if (is_dot_or_dash (*p)) { ref_tail_fields = p; break; } for (p = cp; *p; ++p) continue; cp_end = p; exact_mode = false; } /* Add all relevant variants. */ { unsigned symbol_index; variant_count = 0; for (symbol_index = 0, l = rule; !symbol_list_null (l); ++symbol_index, l = l->next) { variant *var; if (l->content_type != SYMLIST_SYMBOL) continue; var = variant_add (l->content.sym->tag, l->sym_loc, symbol_index, cp, cp_end, exact_mode); if (var && l->named_ref) var->hidden_by = l->named_ref; if (l->named_ref) variant_add (l->named_ref->id, l->named_ref->loc, symbol_index, cp, cp_end, exact_mode); } } /* Check errors. */ for (i = 0; i < variant_count; ++i) { variant *var = &variant_table[i]; unsigned symbol_index = var->symbol_index; /* Check visibility from mid-rule actions. */ if (midrule_rhs_index != 0 && (symbol_index == 0 || midrule_rhs_index < symbol_index)) var->err |= VARIANT_NOT_VISIBLE_FROM_MIDRULE; /* Check correct bracketing. */ if (!exact_mode && contains_dot_or_dash (var->id)) var->err |= VARIANT_BAD_BRACKETING; /* Check using of hidden symbols. */ if (var->hidden_by) var->err |= VARIANT_HIDDEN; if (!var->err) { valid_variant_index = i; ++valid_variants; } } switch (valid_variants) { case 0: if (variant_count == 0) complain_at (text_loc, _("invalid reference: %s, symbol not found"), quote (text)); else { complain_at (text_loc, _("invalid reference: %s"), quote (text)); show_sub_messages (cp, exact_mode, midrule_rhs_index, dollar_or_at, false); } return INVALID_REF; case 1: { if (variant_count > 1) { warn_at (text_loc, _("misleading reference: %s"), quote (text)); show_sub_messages (cp, exact_mode, midrule_rhs_index, dollar_or_at, true); } { unsigned symbol_index = variant_table[valid_variant_index].symbol_index; return (symbol_index == midrule_rhs_index) ? LHS_REF : symbol_index; } } case 2: default: complain_at (text_loc, _("ambiguous reference: %s"), quote (text)); show_sub_messages (cp, exact_mode, midrule_rhs_index, dollar_or_at, false); return INVALID_REF; } /* Not reachable. */ return INVALID_REF; } /* Keeps track of the maximum number of semantic values to the left of a handle (those referenced by $0, $-1, etc.) are required by the semantic actions of this grammar. */ int max_left_semantic_context = 0; /*------------------------------------------------------------------. | TEXT is pointing to a wannabee semantic value (i.e., a `$'). | | | | Possible inputs: $[]($|integer) | | | | Output to OBSTACK_FOR_STRING a reference to this semantic value. | `------------------------------------------------------------------*/ static void handle_action_dollar (symbol_list *rule, char *text, location dollar_loc) { char const *type_name = NULL; char *cp = text + 1; char *gt_ptr = 0; symbol_list *effective_rule; int effective_rule_length; int n; if (rule->midrule_parent_rule) { effective_rule = rule->midrule_parent_rule; effective_rule_length = rule->midrule_parent_rhs_index - 1; } else { effective_rule = rule; effective_rule_length = symbol_list_length (rule->next); } /* Get the type name if explicit. */ if (*cp == '<') { type_name = ++cp; while (*cp != '>') ++cp; /* The '>' symbol will be later replaced by '\0'. Original 'text' is needed for error messages. */ gt_ptr = cp; ++cp; if (untyped_var_seen) complain_at (dollar_loc, _("explicit type given in untyped grammar")); tag_seen = true; } n = parse_ref (cp, effective_rule, effective_rule_length, rule->midrule_parent_rhs_index, text, dollar_loc, '$'); if (gt_ptr) *gt_ptr = '\0'; switch (n) { case INVALID_REF: break; case LHS_REF: if (!type_name) type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0); if (!type_name) { if (union_seen | tag_seen) { if (rule->midrule_parent_rule) complain_at (dollar_loc, _("$$ for the midrule at $%d of `%s'" " has no declared type"), rule->midrule_parent_rhs_index, effective_rule->content.sym->tag); else complain_at (dollar_loc, _("$$ of `%s' has no declared type"), rule->content.sym->tag); } else untyped_var_seen = true; type_name = ""; } obstack_fgrow1 (&obstack_for_string, "]b4_lhs_value([%s])[", type_name); rule->action_props.is_value_used = true; break; default: if (max_left_semantic_context < 1 - n) max_left_semantic_context = 1 - n; if (!type_name && 0 < n) type_name = symbol_list_n_type_name_get (effective_rule, dollar_loc, n); if (!type_name) { if (union_seen | tag_seen) complain_at (dollar_loc, _("$%s of `%s' has no declared type"), cp, effective_rule->content.sym->tag); else untyped_var_seen = true; type_name = ""; } obstack_fgrow3 (&obstack_for_string, "]b4_rhs_value(%d, %d, [%s])[", effective_rule_length, n, type_name); if (n > 0) symbol_list_n_get (effective_rule, n)->action_props.is_value_used = true; break; } } /*------------------------------------------------------. | TEXT is a location token (i.e., a `@...'). Output to | | OBSTACK_FOR_STRING a reference to this location. | `------------------------------------------------------*/ static void handle_action_at (symbol_list *rule, char *text, location at_loc) { char *cp = text + 1; symbol_list *effective_rule; int effective_rule_length; int n; if (rule->midrule_parent_rule) { effective_rule = rule->midrule_parent_rule; effective_rule_length = rule->midrule_parent_rhs_index - 1; } else { effective_rule = rule; effective_rule_length = symbol_list_length (rule->next); } locations_flag = true; n = parse_ref (cp, effective_rule, effective_rule_length, rule->midrule_parent_rhs_index, text, at_loc, '@'); switch (n) { case INVALID_REF: break; case LHS_REF: obstack_sgrow (&obstack_for_string, "]b4_lhs_location["); break; default: obstack_fgrow2 (&obstack_for_string, "]b4_rhs_location(%d, %d)[", effective_rule_length, n); break; } } /*-------------------------. | Initialize the scanner. | `-------------------------*/ /* Translate the dollars and ats in \a self, in the context \a sc_context (SC_RULE_ACTION, SC_SYMBOL_ACTION, INITIAL). */ static char const * translate_action (code_props *self, int sc_context) { char *res; static bool initialized = false; if (!initialized) { obstack_init (&obstack_for_string); yy_flex_debug = 0; initialized = true; } loc->start = loc->end = self->location.start; yy_switch_to_buffer (yy_scan_string (self->code)); res = code_lex (self, sc_context); yy_delete_buffer (YY_CURRENT_BUFFER); return res; } /*------------------------------------------------------------------------. | Implementation of the public interface as documented in "scan-code.h". | `------------------------------------------------------------------------*/ void code_props_none_init (code_props *self) { *self = code_props_none; } code_props const code_props_none = CODE_PROPS_NONE_INIT; void code_props_plain_init (code_props *self, char const *code, location code_loc) { self->kind = CODE_PROPS_PLAIN; self->code = code; self->location = code_loc; self->is_value_used = false; self->rule = NULL; self->named_ref = NULL; } void code_props_symbol_action_init (code_props *self, char const *code, location code_loc) { self->kind = CODE_PROPS_SYMBOL_ACTION; self->code = code; self->location = code_loc; self->is_value_used = false; self->rule = NULL; self->named_ref = NULL; } void code_props_rule_action_init (code_props *self, char const *code, location code_loc, symbol_list *rule, named_ref *name) { self->kind = CODE_PROPS_RULE_ACTION; self->code = code; self->location = code_loc; self->is_value_used = false; self->rule = rule; self->named_ref = name; } void code_props_translate_code (code_props *self) { switch (self->kind) { case CODE_PROPS_NONE: break; case CODE_PROPS_PLAIN: self->code = translate_action (self, INITIAL); break; case CODE_PROPS_SYMBOL_ACTION: self->code = translate_action (self, SC_SYMBOL_ACTION); break; case CODE_PROPS_RULE_ACTION: self->code = translate_action (self, SC_RULE_ACTION); break; } } void code_scanner_last_string_free (void) { STRING_FREE; } void code_scanner_free (void) { obstack_free (&obstack_for_string, 0); variant_table_free (); /* Reclaim Flex's buffers. */ yylex_destroy (); }