X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/f16b08196c780556cbf50691e2944960aebc46f6..5422d56a718805a2470558808355e04182a12d65:/src/scan-code.l diff --git a/src/scan-code.l b/src/scan-code.l index 630d45d5..c13f8805 100644 --- a/src/scan-code.l +++ b/src/scan-code.l @@ -1,6 +1,6 @@ /* Bison Action Scanner -*- C -*- - Copyright (C) 2006, 2007 Free Software Foundation, Inc. + Copyright (C) 2006-2011 Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -17,7 +17,7 @@ You should have received a copy of the GNU General Public License along with this program. If not, see . */ -%option debug nodefault nounput noyywrap never-interactive +%option debug nodefault noinput nounput noyywrap never-interactive %option prefix="code_" outfile="lex.yy.c" %{ @@ -32,12 +32,13 @@ #include "complain.h" #include "reader.h" #include "getargs.h" -#include -#include - #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) @@ -48,6 +49,10 @@ YY_DECL; 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; @@ -56,6 +61,7 @@ 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 @@ -75,12 +81,32 @@ tag [^\0\n>]+ 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. */ @@ -135,10 +161,12 @@ splice (\\[ \f\t\v]*\n)* "'" { STRING_GROW; BEGIN SC_CHARACTER; + need_semicolon = true; } "\"" { STRING_GROW; BEGIN SC_STRING; + need_semicolon = true; } "/"{splice}"*" { STRING_GROW; @@ -152,45 +180,85 @@ splice (\\[ \f\t\v]*\n)* { - "$"("<"{tag}">")?(-?[0-9]+|"$") { + "$"("<"{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; } - "@"(-?[0-9]+|"$") { + "@"{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; ++braces_level; + ";" STRING_GROW; need_semicolon = false; + "{" STRING_GROW; ++braces_level; need_semicolon = false; "}" { - bool outer_brace = --braces_level < 0; + 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. - - FIXME: Bison should warn if a semicolon seems to be necessary - here, and should omit the semicolon if it seems unnecessary - (e.g., after ';', '{', or '}', each followed by comments or - white space). Such a warning shouldn't depend on --yacc; it - should depend on a new --pedantic option, which would cause - Bison to warn if it detects an extension to POSIX. --pedantic - should also diagnose other Bison extensions like %yacc. - Perhaps there should also be a GCC-style --pedantic-errors - option, so that such warnings are diagnosed as errors. */ - if (outer_brace && ! yacc_flag) - obstack_1grow (&obstack_for_string, ';'); + 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; + + /* YYFAIL is undocumented and was formally deprecated in Bison + 2.4.2. */ + YYFAIL { + STRING_GROW; need_semicolon = true; + warn_at (*loc, _("use of YYFAIL, which is deprecated and will be" + " removed")); } + + /* The sole purpose of this is to make sure identifiers that merely + contain YYFAIL don't produce the above warning. */ + [A-Za-z_][0-9A-Za-z_]* STRING_GROW; need_semicolon = true; + + . STRING_GROW; need_semicolon = true; } @@ -232,6 +300,388 @@ splice (\\[ \f\t\v]*\n)* %% +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 explicit_bracketing) +{ + char *prefix_end; + + prefix_end = find_prefix_end (id, cp, cp_end); + if (prefix_end && + (prefix_end == cp_end || + (!explicit_bracketing && 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 explicit_bracketing, + int midrule_rhs_index, char dollar_or_at, + bool is_warning, unsigned indent) +{ + 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_indent (var->loc, &indent, _("refers to: %c%s at %s"), + dollar_or_at, var->id, at_spec); + else + complain_at_indent (var->loc, &indent, _("refers to: %c%s at %s"), + dollar_or_at, var->id, at_spec); + } + else + { + static struct obstack msg_buf; + const char *tail = explicit_bracketing ? "" : + 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) + { + const char *format = + _(", cannot be accessed from mid-rule action at $%d"); + obstack_fgrow1 (&msg_buf, format, midrule_rhs_index); + } + + obstack_1grow (&msg_buf, '\0'); + if (is_warning) + warn_at_indent (id_loc, &indent, "%s", + (char *) obstack_finish (&msg_buf)); + else + complain_at_indent (id_loc, &indent, "%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) + +/* Sub-messages indent. */ +#define SUB_INDENT (4) + +/* Parse named or positional reference. In case of positional + references, can return negative values for $-n "deep" stack + accesses. */ +static long int +parse_ref (char *cp, symbol_list *rule, int rule_length, + int midrule_rhs_index, char *text, location text_loc, + char dollar_or_at) +{ + symbol_list *l; + char *cp_end; + bool explicit_bracketing; + unsigned i; + unsigned valid_variants = 0; + unsigned valid_variant_index = 0; + + if ('$' == *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; + + explicit_bracketing = 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; + + explicit_bracketing = 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, explicit_bracketing); + 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, explicit_bracketing); + } + } + + /* 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 (!explicit_bracketing && 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: + { + unsigned len = (explicit_bracketing || !ref_tail_fields) ? + cp_end - cp : ref_tail_fields - cp; + unsigned indent = 0; + + complain_at_indent (text_loc, &indent, _("invalid reference: %s"), + quote (text)); + indent += SUB_INDENT; + if (len == 0) + { + location sym_loc = text_loc; + sym_loc.start.column += 1; + sym_loc.end = sym_loc.start; + const char *format = + _("syntax error after `%c', expecting integer, letter," + " `_', `[', or `$'"); + complain_at_indent (sym_loc, &indent, format, dollar_or_at); + } + else if (midrule_rhs_index) + { + const char *format = + _("symbol not found in production before $%d: %.*s"); + complain_at_indent (rule->location, &indent, format, + midrule_rhs_index, len, cp); + } + else + { + const char *format = + _("symbol not found in production: %.*s"); + complain_at_indent (rule->location, &indent, format, + len, cp); + } + + if (variant_count > 0) + show_sub_messages (cp, explicit_bracketing, midrule_rhs_index, + dollar_or_at, false, indent); + return INVALID_REF; + } + case 1: + { + unsigned indent = 0; + if (variant_count > 1) + { + warn_at_indent (text_loc, &indent, _("misleading reference: %s"), + quote (text)); + show_sub_messages (cp, explicit_bracketing, midrule_rhs_index, + dollar_or_at, true, indent + SUB_INDENT); + } + { + unsigned symbol_index = + variant_table[valid_variant_index].symbol_index; + return (symbol_index == midrule_rhs_index) ? LHS_REF : symbol_index; + } + } + case 2: + default: + { + unsigned indent = 0; + complain_at_indent (text_loc, &indent, _("ambiguous reference: %s"), + quote (text)); + show_sub_messages (cp, explicit_bracketing, midrule_rhs_index, + dollar_or_at, false, indent + SUB_INDENT); + 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, $-1, etc.) are required by the semantic actions of this grammar. */ @@ -251,8 +701,10 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc) { char const *type_name = NULL; char *cp = text + 1; + char *gt_ptr = 0; symbol_list *effective_rule; int effective_rule_length; + int n; if (rule->midrule_parent_rule) { @@ -271,15 +723,28 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc) type_name = ++cp; while (*cp != '>') ++cp; - *cp = '\0'; + + /* The '>' symbol will be later replaced by '\0'. Original + 'text' is needed for error messages. */ + gt_ptr = cp; ++cp; if (untyped_var_seen) complain_at (dollar_loc, _("explicit type given in untyped grammar")); tag_seen = true; } - if (*cp == '$') + n = parse_ref (cp, effective_rule, effective_rule_length, + rule->midrule_parent_rhs_index, text, dollar_loc, '$'); + + if (gt_ptr) + *gt_ptr = '\0'; + + switch (n) { + case INVALID_REF: + break; + + case LHS_REF: if (!type_name) type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0); @@ -305,39 +770,31 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc) obstack_fgrow1 (&obstack_for_string, "]b4_lhs_value([%s])[", type_name); rule->action_props.is_value_used = true; - } - else - { - long int num = strtol (cp, NULL, 10); - - if (1 - INT_MAX + effective_rule_length <= num - && num <= effective_rule_length) + break; + + default: + if (max_left_semantic_context < 1 - n) + max_left_semantic_context = 1 - n; + if (!type_name && 0 < n) + type_name = + symbol_list_n_type_name_get (effective_rule, dollar_loc, n); + if (!type_name) { - int n = num; - if (max_left_semantic_context < 1 - n) - max_left_semantic_context = 1 - n; - if (!type_name && 0 < n) - type_name = - symbol_list_n_type_name_get (effective_rule, dollar_loc, n); - if (!type_name) - { - if (union_seen | tag_seen) - complain_at (dollar_loc, _("$%d of `%s' has no declared type"), - n, 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; + if (union_seen | tag_seen) + complain_at (dollar_loc, _("$%s of `%s' has no declared type"), + cp, effective_rule->content.sym->tag); + else + untyped_var_seen = true; + type_name = ""; } - else - complain_at (dollar_loc, _("integer out of range: %s"), quote (text)); + + obstack_fgrow3 (&obstack_for_string, + "]b4_rhs_value(%d, %d, [%s])[", + effective_rule_length, n, type_name); + if (n > 0) + symbol_list_n_get (effective_rule, n)->action_props.is_value_used = + true; + break; } } @@ -351,28 +808,38 @@ static void handle_action_at (symbol_list *rule, char *text, location at_loc) { char *cp = text + 1; - int effective_rule_length = - (rule->midrule_parent_rule - ? rule->midrule_parent_rhs_index - 1 - : symbol_list_length (rule->next)); + symbol_list *effective_rule; + int effective_rule_length; + int n; + + if (rule->midrule_parent_rule) + { + effective_rule = rule->midrule_parent_rule; + effective_rule_length = rule->midrule_parent_rhs_index - 1; + } + else + { + effective_rule = rule; + effective_rule_length = symbol_list_length (rule->next); + } locations_flag = true; - if (*cp == '$') - obstack_sgrow (&obstack_for_string, "]b4_lhs_location["); - else + n = parse_ref (cp, effective_rule, effective_rule_length, + rule->midrule_parent_rhs_index, text, at_loc, '@'); + switch (n) { - long int num = strtol (cp, NULL, 10); + case INVALID_REF: + break; - if (1 - INT_MAX + effective_rule_length <= num - && num <= effective_rule_length) - { - int n = num; - obstack_fgrow2 (&obstack_for_string, "]b4_rhs_location(%d, %d)[", - effective_rule_length, n); - } - else - complain_at (at_loc, _("integer out of range: %s"), quote (text)); + 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; } } @@ -417,13 +884,15 @@ code_props_none_init (code_props *self) code_props const code_props_none = CODE_PROPS_NONE_INIT; void -code_props_plain_init (code_props *self, char const *code, location code_loc) +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 @@ -435,17 +904,20 @@ code_props_symbol_action_init (code_props *self, char const *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) + 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 @@ -477,6 +949,8 @@ void code_scanner_free (void) { obstack_free (&obstack_for_string, 0); + variant_table_free (); + /* Reclaim Flex's buffers. */ yylex_destroy (); }