/* Bison Action Scanner -*- C -*-
Copyright (C) 2006-2015, 2018-2021 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 <https://www.gnu.org/licenses/>. */
%option debug nodefault noinput nounput noyywrap never-interactive
%option prefix="code_" outfile="lex.yy.c"
%{
#include <c-ctype.h>
#include <get-errno.h>
#include <quote.h>
#include "src/complain.h"
#include "src/getargs.h"
#include "src/muscle-tab.h"
#include "src/reader.h"
#include "src/scan-code.h"
#include "src/symlist.h"
#define FLEX_PREFIX(Id) code_ ## Id
#include "src/flex-scanner.h"
/* Work around a bug in flex 2.5.31. See Debian bug 333231
<https://bugs.debian.org/333231>. */
#undef code_wrap
#define code_wrap() 1
struct obstack *obstack_for_actions = &obstack_for_string;
/* 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 char *fetch_type_name (char *cp, char const **type_name,
const location *dollar_loc);
static void handle_action_dollar (symbol_list *rule, char *cp,
const location *dollar_loc);
static void handle_action_at (symbol_list *rule, char *cp,
const location *at_loc);
/* A string to be pushed to obstack after dollar/at has been handled. */
static char *ref_tail_fields;
static location current_loc;
static location *loc = ¤t_loc;
/* 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. We allow
"->" as a means to dereference a pointer. */
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}"]"|"$"
%%
%{
/* This scanner is special: it is invoked only once, henceforth
is expected to return only once. This initialization is
therefore done once per action to translate. */
aver (sc_context == SC_SYMBOL_ACTION
|| sc_context == SC_RULE_ACTION
|| sc_context == INITIAL);
BEGIN sc_context;
%}
/*------------------------------------------------------------.
| Scanning a C comment. The initial '/ *' is already eaten. |
`------------------------------------------------------------*/
<SC_COMMENT>
{
"*"{splice}"/" STRING_GROW (); BEGIN sc_context;
}
/*--------------------------------------------------------------.
| Scanning a line comment. The initial '//' is already eaten. |
`--------------------------------------------------------------*/
<SC_LINE_COMMENT>
{
"\n" STRING_GROW (); BEGIN sc_context;
{splice} STRING_GROW ();
}
/*--------------------------------------------.
| Scanning user-code characters and strings. |
`--------------------------------------------*/
<SC_CHARACTER,SC_STRING>
{
{splice}|\\{splice}. STRING_GROW ();
}
<SC_CHARACTER>
{
"'" STRING_GROW (); BEGIN sc_context;
}
<SC_STRING>
{
"\"" STRING_GROW (); BEGIN sc_context;
}
<SC_RULE_ACTION,SC_SYMBOL_ACTION>
{
"'" STRING_GROW (); BEGIN SC_CHARACTER;
"\"" STRING_GROW (); BEGIN SC_STRING;
"/"{splice}"*" STRING_GROW (); BEGIN SC_COMMENT;
"/"{splice}"/" STRING_GROW (); BEGIN SC_LINE_COMMENT;
[$@] {
complain (loc, Wother, _("stray '%s'"), yytext);
obstack_escape (&obstack_for_string, yytext);
}
}
<SC_RULE_ACTION>
{
"$"("<"{tag}">")?{ref} {
ref_tail_fields = NULL;
handle_action_dollar (self->rule, yytext, loc);
if (ref_tail_fields)
obstack_sgrow (&obstack_for_string, ref_tail_fields);
}
"@"{ref} {
ref_tail_fields = NULL;
handle_action_at (self->rule, yytext, loc);
if (ref_tail_fields)
obstack_sgrow (&obstack_for_string, ref_tail_fields);
}
}
<SC_SYMBOL_ACTION>
{
"$"("<"{tag}">")?"$" {
const char *type_name = NULL;
fetch_type_name (yytext + 1, &type_name, loc)[-1] = 0;
obstack_sgrow (&obstack_for_string, "]b4_dollar_dollar(");
obstack_quote (&obstack_for_string, type_name);
obstack_sgrow (&obstack_for_string, ")[");
self->is_value_used = true;
}
"@$" {
obstack_sgrow (&obstack_for_string, "]b4_at_dollar[");
muscle_percent_define_ensure("locations", *loc, true);
}
}
<*>
{
/* Escape M4 quoting characters in C code. */
[$@\[\]] obstack_escape (&obstack_for_string, yytext);
/* By default, grow the string obstack with the input. */
.|\n STRING_GROW ();
/* End of processing. */
<<EOF>> 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)
{
return !!strpbrk (p, ".-");
}
/* Defines a variant of a symbolic name resolution. */
typedef struct
{
/* Index in symbol list. */
int 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 = NULL;
static int variant_table_size = 0;
static int 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 = NULL;
variant_table_size = variant_count = 0;
}
static char const *
find_prefix_end (char const *prefix, char const *cp, char const *end)
{
for (; *prefix && cp != end; ++prefix, ++cp)
if (*prefix != *cp)
return NULL;
return *prefix ? NULL : cp;
}
static variant *
variant_add (uniqstr id, location id_loc, int symbol_index,
char const *cp, char const *cp_end, bool explicit_bracketing)
{
char const *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(int symbol_index)
{
static char at_buf[20];
if (symbol_index == 0)
strcpy (at_buf, "$$");
else
snprintf (at_buf, sizeof at_buf, "$%u", symbol_index);
return at_buf;
}
static void
show_sub_message (warnings warning,
const char* cp, bool explicit_bracketing,
int midrule_rhs_index, char dollar_or_at,
const variant *var)
{
const char *at_spec = get_at_spec (var->symbol_index);
if (var->err == 0)
subcomplain (&var->loc, warning,
_("refers to: %c%s at %s"), dollar_or_at,
var->id, at_spec);
else
{
const char *id;
location id_loc;
if (var->hidden_by)
{
id = var->hidden_by->id;
id_loc = var->hidden_by->loc;
}
else
{
id = var->id;
id_loc = var->loc;
}
const char *tail = explicit_bracketing ? "" : cp + strlen (var->id);
/* Create the explanation message. */
static struct obstack msg_buf;
obstack_init (&msg_buf);
obstack_printf (&msg_buf, _("possibly meant: %c"), dollar_or_at);
if (contains_dot_or_dash (id))
obstack_printf (&msg_buf, "[%s]", id);
else
obstack_sgrow (&msg_buf, id);
obstack_sgrow (&msg_buf, tail);
if (var->err & VARIANT_HIDDEN)
{
obstack_printf (&msg_buf, _(", hiding %c"), dollar_or_at);
if (contains_dot_or_dash (var->id))
obstack_printf (&msg_buf, "[%s]", var->id);
else
obstack_sgrow (&msg_buf, var->id);
obstack_sgrow (&msg_buf, tail);
}
obstack_printf (&msg_buf, _(" at %s"), at_spec);
if (var->err & VARIANT_NOT_VISIBLE_FROM_MIDRULE)
obstack_printf (&msg_buf,
_(", cannot be accessed from midrule action at $%d"),
midrule_rhs_index);
subcomplain (&id_loc, warning, "%s",
obstack_finish0 (&msg_buf));
obstack_free (&msg_buf, 0);
}
}
static void
show_sub_messages (warnings warning,
const char* cp, bool explicit_bracketing,
int midrule_rhs_index, char dollar_or_at)
{
for (int i = 0; i < variant_count; ++i)
show_sub_message (warning | silent,
cp, explicit_bracketing,
midrule_rhs_index, dollar_or_at,
&variant_table[i]);
}
/* Returned from "parse_ref" when the reference
is inappropriate. */
#define INVALID_REF (INT_MIN)
/* Returned from "parse_ref" when the reference
points to LHS ($$) of the current rule or midrule. */
#define LHS_REF (INT_MIN + 1)
/* Parse a positional reference in RULE. */
static long
parse_positional_ref (char *cp, int rule_length,
char *text, const location *text_loc)
{
long num = strtol (cp, &cp, 10);
if (1 - INT_MAX + rule_length <= num && num <= rule_length)
return num;
else
{
complain (text_loc, complaint, _("integer out of range: %s"),
quote (text));
return INVALID_REF;
}
}
/* Parse named or positional reference. In case of positional
references, can return negative values for $-n "deep" stack
accesses. */
static long
parse_ref (char *cp, symbol_list *rule, int rule_length,
int midrule_rhs_index, char *text, const location *text_loc,
char dollar_or_at)
{
if ('$' == *cp)
return LHS_REF;
if (c_isdigit (*cp) || (*cp == '-' && c_isdigit (cp[1])))
return parse_positional_ref (cp, rule_length, text, text_loc);
bool const explicit_bracketing = *cp == '[';
if (explicit_bracketing)
++cp;
else
ref_tail_fields = strpbrk (cp, ".-");
char const *cp_end = strchr (cp, explicit_bracketing ? ']' : '\0');
/* Add all relevant variants. */
{
int symbol_index;
symbol_list *l;
variant_count = 0;
for (symbol_index = 0, l = rule; !symbol_list_null (l);
++symbol_index, l = l->next)
{
if (l->content_type != SYMLIST_SYMBOL)
continue;
variant *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. */
int valid_variants = 0;
int valid_variant_index = 0;
for (int i = 0; i < variant_count; ++i)
{
variant *var = &variant_table[i];
int symbol_index = var->symbol_index;
/* Check visibility from midrule 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:
{
int len = (explicit_bracketing || !ref_tail_fields) ?
cp_end - cp : ref_tail_fields - cp;
complain (text_loc, complaint,
_("invalid reference: %s"), quote (text));
if (len == 0)
{
location sym_loc = *text_loc;
sym_loc.start.column += 1;
sym_loc.end = sym_loc.start;
subcomplain (&sym_loc, complaint,
_("syntax error after '%c', expecting integer, "
"letter, '_', '[', or '$'"),
dollar_or_at);
}
else if (midrule_rhs_index)
subcomplain (&rule->rhs_loc, complaint,
_("symbol not found in production before $%d: "
"%.*s"),
midrule_rhs_index, len, cp);
else
subcomplain (&rule->rhs_loc, complaint,
_("symbol not found in production: %.*s"),
len, cp);
if (variant_count > 0)
show_sub_messages (complaint,
cp, explicit_bracketing, midrule_rhs_index,
dollar_or_at);
return INVALID_REF;
}
case 1:
{
if (variant_count > 1)
{
complain (text_loc, Wother,
_("misleading reference: %s"), quote (text));
show_sub_messages (Wother,
cp, explicit_bracketing, midrule_rhs_index,
dollar_or_at);
}
{
int symbol_index =
variant_table[valid_variant_index].symbol_index;
return (symbol_index == midrule_rhs_index) ? LHS_REF : symbol_index;
}
}
case 2:
default:
{
complain (text_loc, complaint,
_("ambiguous reference: %s"), quote (text));
show_sub_messages (complaint,
cp, explicit_bracketing, midrule_rhs_index,
dollar_or_at);
return INVALID_REF;
}
}
}
/* Keeps track of the maximum number of semantic values to the left of
a handle (those referenced by $0, $-1, etc.) are required by the
semantic actions of this grammar. */
int max_left_semantic_context = 0;
/* If CP points to a typename (i.e., <.*?>), set TYPE_NAME to its
beginning (i.e., after the opening "<", and return the pointer
immediately after it. */
static
char *
fetch_type_name (char *cp, char const **type_name,
const location *dollar_loc)
{
if (*cp == '<')
{
*type_name = ++cp;
/* Series of non-'>' or "->". */
while (*cp != '>' || cp[-1] == '-')
++cp;
/* The '>' symbol will be later replaced by '\0'. Original
'text' is needed for error messages. */
++cp;
if (untyped_var_seen)
complain (dollar_loc, complaint,
_("explicit type given in untyped grammar"));
tag_seen = true;
}
return cp;
}
/*------------------------------------------------------------------.
| TEXT is pointing to a wannabee semantic value (i.e., a '$'). |
| |
| Possible inputs: $[<TYPENAME>]($|INTEGER) |
| |
| Output to OBSTACK_FOR_STRING a reference to this semantic value. |
`------------------------------------------------------------------*/
static void
handle_action_dollar (symbol_list *rule, char *text, const location *dollar_loc)
{
symbol_list *effective_rule;
int effective_rule_length;
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);
}
/* The type name if explicit, otherwise left null. */
char const *type_name = NULL;
char *cp = fetch_type_name (text + 1, &type_name, dollar_loc);
int n = parse_ref (cp, effective_rule, effective_rule_length,
rule->midrule_parent_rhs_index, text, dollar_loc, '$');
/* End type_name. Don't do it earlier: parse_ref depends on TEXT. */
if (type_name)
cp[-1] = '\0';
switch (n)
{
case INVALID_REF:
break;
case LHS_REF:
{
symbol_list *sym = symbol_list_n_get (rule, 0);
if (!type_name
&& !sym->content.sym->content->type_name)
{
if (union_seen || tag_seen)
{
if (rule->midrule_parent_rule)
complain (dollar_loc, complaint,
_("$$ for the midrule at $%d of %s"
" has no declared type"),
rule->midrule_parent_rhs_index,
quote (effective_rule->content.sym->tag));
else
complain (dollar_loc, complaint,
_("$$ of %s has no declared type"),
quote (rule->content.sym->tag));
}
else
untyped_var_seen = true;
}
obstack_printf (&obstack_for_string, "]b4_lhs_value(orig %d, ",
sym->content.sym->content->number);
obstack_quote (&obstack_for_string, type_name);
obstack_sgrow (&obstack_for_string, ")[");
rule->action_props.is_value_used = true;
}
break;
/* Reference to a RHS symbol. */
default:
{
if (max_left_semantic_context < 1 - n)
max_left_semantic_context = 1 - n;
symbol_list *sym = 0 < n ? symbol_list_n_get (effective_rule, n) : NULL;
if (!type_name
&& (!sym || !sym->content.sym->content->type_name))
{
if (union_seen || tag_seen)
complain (dollar_loc, complaint,
_("$%s of %s has no declared type"), cp,
quote (effective_rule->content.sym->tag));
else
untyped_var_seen = true;
}
obstack_printf (&obstack_for_string,
"]b4_rhs_value(%d, %d, ",
effective_rule_length, n);
if (sym)
obstack_printf (&obstack_for_string, "%s%d, ",
sym->content.sym->content->class == nterm_sym ? "orig " : "",
sym->content.sym->content->number);
else
obstack_sgrow (&obstack_for_string, "[], ");
obstack_quote (&obstack_for_string, type_name);
obstack_sgrow (&obstack_for_string, ")[");
if (0 < n)
{
if (muscle_percent_define_ifdef ("api.value.automove")
&& sym->action_props.is_value_used)
complain (dollar_loc, Wother,
_("multiple occurrences of $%d with api.value.automove"),
n);
sym->action_props.is_value_used = true;
}
}
break;
}
}
/*------------------------------------------------------.
| TEXT is a location token (i.e., a '@...'). Output to |
| OBSTACK_FOR_STRING a reference to this location. |
`------------------------------------------------------*/
static void
handle_action_at (symbol_list *rule, char *text, const location *at_loc)
{
symbol_list *effective_rule;
int effective_rule_length;
if (rule->midrule_parent_rule)
{
effective_rule = rule->midrule_parent_rule;
effective_rule_length = rule->midrule_parent_rhs_index - 1;
}
else
{
effective_rule = rule;
effective_rule_length = symbol_list_length (rule->next);
}
muscle_percent_define_ensure ("locations", *at_loc, true);
int n = parse_ref (text + 1, effective_rule, effective_rule_length,
rule->midrule_parent_rhs_index, text, at_loc, '@');
switch (n)
{
case INVALID_REF:
break;
case LHS_REF:
obstack_sgrow (&obstack_for_string, "]b4_lhs_location[");
break;
default:
obstack_printf (&obstack_for_string, "]b4_rhs_location(%d, %d)[",
effective_rule_length, n);
break;
}
}
/*-------------------------.
| Initialize the scanner. |
`-------------------------*/
/* Translate the '$...' and '@...' 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)
{
loc->start = loc->end = self->location.start;
yy_switch_to_buffer (yy_scan_string (self->code));
char *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 code_props_none = CODE_PROPS_NONE_INIT;
void
code_props_plain_init (code_props *self, char const *code,
location code_loc)
{
code_props_none_init (self);
self->kind = CODE_PROPS_PLAIN;
self->code = code;
self->location = code_loc;
}
void
code_props_symbol_action_init (code_props *self, char const *code,
location code_loc)
{
code_props_none_init (self);
self->kind = CODE_PROPS_SYMBOL_ACTION;
self->code = code;
self->location = code_loc;
}
void
code_props_rule_action_init (code_props *self, char const *code,
location code_loc, symbol_list *rule,
named_ref *name, uniqstr type,
bool is_predicate)
{
code_props_none_init (self);
self->kind = CODE_PROPS_RULE_ACTION;
self->code = code;
self->location = code_loc;
self->rule = rule;
self->named_ref = name;
self->type = type;
self->is_predicate = is_predicate;
}
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_init (void)
{
obstack_init (&obstack_for_string);
yy_flex_debug = 0;
}
void
code_scanner_free (void)
{
obstack_free (&obstack_for_string, 0);
variant_table_free ();
/* Reclaim Flex's buffers. */
yylex_destroy ();
}