Future/bison
1
0
Fork 0
mirror of https://git.savannah.gnu.org/git/bison.git synced 2026-04-24 18:52:21 +00:00
Code Issues Packages Projects Releases Wiki Activity
Files
a940e84e293e55228f7c7341bc4cc7b4c6c61c98
bison/src/reader.c
T
Akim Demaille 3e3da79762 * src/print_graph.c (print_actions): CPP out useless code. 
* src/vcg.c (complain.h): Include it.
Unepitaize `return' invocations.
* src/vcg.c [NDEBUG] (main): Remove.
2001-08-06 09:50:38 +00:00

1988 lines
47 KiB
C
Raw Blame History

/* Input parser for bison
Copyright 1984, 1986, 1989, 1992, 1998, 2000
Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
Bison 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 2, or (at your option)
any later version.
Bison 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 Bison; see the file COPYING. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "system.h"
#include "obstack.h"
#include "quotearg.h"
#include "quote.h"
#include "getargs.h"
#include "files.h"
#include "xalloc.h"
#include "symtab.h"
#include "lex.h"
#include "gram.h"
#include "complain.h"
#include "output.h"
#include "reader.h"
#include "conflicts.h"
/* Number of slots allocated (but not necessarily used yet) in `rline' */
static int rline_allocated;
typedef struct symbol_list
{
struct symbol_list *next;
bucket *sym;
bucket *ruleprec;
}
symbol_list;
int lineno;
char **tags;
short *user_toknums;
static symbol_list *grammar;
static int start_flag;
static bucket *startval;
/* 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;
/* Incremented for each %left, %right or %nonassoc seen */
static int lastprec;
static bucket *errtoken;
static bucket *undeftoken;
/*===================\
| Low level lexing. |
\===================*/
static void
skip_to_char (int target)
{
int c;
if (target == '\n')
complain (_(" Skipping to next \\n"));
else
complain (_(" Skipping to next %c"), target);
do
c = skip_white_space ();
while (c != target && c != EOF);
if (c != EOF)
ungetc (c, finput);
}
/*---------------------------------------------------------.
| Read a signed integer from STREAM and return its value. |
`---------------------------------------------------------*/
static inline int
read_signed_integer (FILE *stream)
{
int c = getc (stream);
int sign = 1;
int n = 0;
if (c == '-')
{
c = getc (stream);
sign = -1;
}
while (isdigit (c))
{
n = 10 * n + (c - '0');
c = getc (stream);
}
ungetc (c, stream);
return sign * n;
}
/*--------------------------------------------------------------.
| Get the data type (alternative in the union) of the value for |
| symbol N in rule RULE. |
`--------------------------------------------------------------*/
static char *
get_type_name (int n, symbol_list * rule)
{
int i;
symbol_list *rp;
if (n < 0)
{
complain (_("invalid $ value"));
return NULL;
}
rp = rule;
i = 0;
while (i < n)
{
rp = rp->next;
if (rp == NULL || rp->sym == NULL)
{
complain (_("invalid $ value"));
return NULL;
}
i++;
}
return rp->sym->type_name;
}
/*------------------------------------------------------------.
| Dump the string from FIN to OOUT if non null. MATCH is the |
| delimiter of the string (either ' or "). |
`------------------------------------------------------------*/
static inline void
copy_string (FILE *fin, struct obstack *oout, int match)
{
int c;
obstack_1grow (oout, match);
c = getc (fin);
while (c != match)
{
if (c == EOF)
fatal (_("unterminated string at end of file"));
if (c == '\n')
{
complain (_("unterminated string"));
ungetc (c, fin);
c = match; /* invent terminator */
continue;
}
obstack_1grow (oout, c);
if (c == '\\')
{
c = getc (fin);
if (c == EOF)
fatal (_("unterminated string at end of file"));
obstack_1grow (oout, c);
if (c == '\n')
lineno++;
}
c = getc (fin);
}
obstack_1grow (oout, c);
}
/*-----------------------------------------------------------------.
| Dump the wannabee comment from IN to OUT1 and OUT2 (which can be |
| NULL). In fact we just saw a `/', which might or might not be a |
| comment. In any case, copy what we saw. |
| |
| OUT2 might be NULL. |
`-----------------------------------------------------------------*/
static inline void
copy_comment2 (FILE *fin, struct obstack *oout1, struct obstack *oout2)
{
int cplus_comment;
int ended;
int c;
/* We read a `/', output it. */
obstack_1grow (oout1, '/');
if (oout2)
obstack_1grow (oout2, '/');
switch ((c = getc (fin)))
{
case '/':
cplus_comment = 1;
break;
case '*':
cplus_comment = 0;
break;
default:
ungetc (c, fin);
return;
}
obstack_1grow (oout1, c);
if (oout2)
obstack_1grow (oout2, c);
c = getc (fin);
ended = 0;
while (!ended)
{
if (!cplus_comment && c == '*')
{
while (c == '*')
{
obstack_1grow (oout1, c);
if (oout2)
obstack_1grow (oout2, c);
c = getc (fin);
}
if (c == '/')
{
obstack_1grow (oout1, c);
if (oout2)
obstack_1grow (oout2, c);
ended = 1;
}
}
else if (c == '\n')
{
lineno++;
obstack_1grow (oout1, c);
if (oout2)
obstack_1grow (oout2, c);
if (cplus_comment)
ended = 1;
else
c = getc (fin);
}
else if (c == EOF)
fatal (_("unterminated comment"));
else
{
obstack_1grow (oout1, c);
if (oout2)
obstack_1grow (oout2, c);
c = getc (fin);
}
}
}
/*-------------------------------------------------------------------.
| Dump the comment (actually the current string starting with a `/') |
| from FIN to OOUT. |
`-------------------------------------------------------------------*/
static inline void
copy_comment (FILE *fin, struct obstack *oout)
{
copy_comment2 (fin, oout, NULL);
}
/*-----------------------------------------------------------------.
| FIN is pointing to a location (i.e., a `@'). Output to OOUT a |
| reference to this location. STACK_OFFSET is the number of values |
| in the current rule so far, which says where to find `$0' with |
| respect to the top of the stack. |
`-----------------------------------------------------------------*/
static inline void
copy_at (FILE *fin, struct obstack *oout, int stack_offset)
{
int c;
c = getc (fin);
if (c == '$')
{
obstack_sgrow (oout, "yyloc");
locations_flag = 1;
}
else if (isdigit (c) || c == '-')
{
int n;
ungetc (c, fin);
n = read_signed_integer (fin);
obstack_fgrow1 (oout, "yylsp[%d]", n - stack_offset);
locations_flag = 1;
}
else
{
char buf[] = "@c";
buf[1] = c;
complain (_("%s is invalid"), quote (buf));
}
}
/*-------------------------------------------------------------------.
| FIN is pointing to a wannabee semantic value (i.e., a `$'). |
| |
| Possible inputs: $[<TYPENAME>]($|integer) |
| |
| Output to OOUT a reference to this semantic value. STACK_OFFSET is |
| the number of values in the current rule so far, which says where |
| to find `$0' with respect to the top of the stack. |
`-------------------------------------------------------------------*/
static inline void
copy_dollar (FILE *fin, struct obstack *oout,
symbol_list *rule, int stack_offset)
{
int c = getc (fin);
const char *type_name = NULL;
/* Get the type name if explicit. */
if (c == '<')
{
read_type_name (fin);
type_name = token_buffer;
value_components_used = 1;
c = getc (fin);
}
if (c == '$')
{
obstack_sgrow (oout, "yyval");
if (!type_name)
type_name = get_type_name (0, rule);
if (type_name)
obstack_fgrow1 (oout, ".%s", type_name);
if (!type_name && typed)
complain (_("$$ of `%s' has no declared type"),
rule->sym->tag);
}
else if (isdigit (c) || c == '-')
{
int n;
ungetc (c, fin);
n = read_signed_integer (fin);
if (!type_name && n > 0)
type_name = get_type_name (n, rule);
obstack_fgrow1 (oout, "yyvsp[%d]", n - stack_offset);
if (type_name)
obstack_fgrow1 (oout, ".%s", type_name);
if (!type_name && typed)
complain (_("$%d of `%s' has no declared type"),
n, rule->sym->tag);
}
else
{
char buf[] = "$c";
buf[1] = c;
complain (_("%s is invalid"), quote (buf));
}
}
/*-------------------------------------------------------------------.
| Copy the contents of a `%{ ... %}' into the definitions file. The |
| `%{' has already been read. Return after reading the `%}'. |
`-------------------------------------------------------------------*/
static void
copy_definition (void)
{
int c;
/* -1 while reading a character if prev char was %. */
int after_percent;
if (!no_lines_flag)
obstack_fgrow2 (&attrs_obstack, "#line %d %s\n",
lineno, quotearg_style (c_quoting_style, infile));
after_percent = 0;
c = getc (finput);
for (;;)
{
switch (c)
{
case '\n':
obstack_1grow (&attrs_obstack, c);
lineno++;
break;
case '%':
after_percent = -1;
break;
case '\'':
case '"':
copy_string (finput, &attrs_obstack, c);
break;
case '/':
copy_comment (finput, &attrs_obstack);
break;
case EOF:
fatal ("%s", _("unterminated `%{' definition"));
default:
obstack_1grow (&attrs_obstack, c);
}
c = getc (finput);
if (after_percent)
{
if (c == '}')
return;
obstack_1grow (&attrs_obstack, '%');
}
after_percent = 0;
}
}
/*-------------------------------------------------------------------.
| 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. |
`-------------------------------------------------------------------*/
static void
parse_token_decl (symbol_class what_is, symbol_class what_is_not)
{
token_t token = 0;
char *typename = 0;
/* The symbol being defined. */
struct bucket *symbol = NULL;
/* After `%token' and `%nterm', any number of symbols maybe be
defined. */
for (;;)
{
int tmp_char = ungetc (skip_white_space (), finput);
/* `%' (for instance from `%token', or from `%%' etc.) is the
only valid means to end this declaration. */
if (tmp_char == '%')
return;
if (tmp_char == EOF)
fatal (_("Premature EOF after %s"), token_buffer);
token = lex ();
if (token == tok_comma)
{
symbol = NULL;
continue;
}
if (token == tok_typename)
{
typename = xstrdup (token_buffer);
value_components_used = 1;
symbol = NULL;
}
else if (token == tok_identifier && *symval->tag == '\"' && symbol)
{
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 = SALIAS;
symval->alias = symbol;
symbol->alias = symval;
/* symbol and symval combined are only one symbol */
nsyms--;
}
translations = 1;
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->value = nvars++;
if (typename)
{
if (symbol->type_name == NULL)
symbol->type_name = typename;
else if (strcmp (typename, symbol->type_name) != 0)
complain (_("type redeclaration for %s"), symbol->tag);
}
}
else if (symbol && token == tok_number)
{
symbol->user_token_number = numval;
translations = 1;
}
else
{
complain (_("`%s' is invalid in %s"),
token_buffer, (what_is == token_sym) ? "%token" : "%nterm");
skip_to_char ('%');
}
}
}
/*------------------------------.
| Parse what comes after %start |
`------------------------------*/
static void
parse_start_decl (void)
{
if (start_flag)
complain (_("multiple %s declarations"), "%start");
if (lex () != tok_identifier)
complain (_("invalid %s declaration"), "%start");
else
{
start_flag = 1;
startval = symval;
}
}
/*-----------------------------------------------------------.
| read in a %type declaration and record its information for |
| get_type_name to access |
`-----------------------------------------------------------*/
static void
parse_type_decl (void)
{
char *name;
if (lex () != tok_typename)
{
complain ("%s", _("%type declaration has no <typename>"));
skip_to_char ('%');
return;
}
name = xstrdup (token_buffer);
for (;;)
{
token_t t;
int tmp_char = ungetc (skip_white_space (), finput);
if (tmp_char == '%')
return;
if (tmp_char == EOF)
fatal (_("Premature EOF after %s"), token_buffer);
t = lex ();
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);
break;
default:
complain (_("invalid %%type declaration due to item: %s"),
token_buffer);
skip_to_char ('%');
}
}
}
/*----------------------------------------------------------------.
| Read in a %left, %right or %nonassoc declaration and record its |
| information. |
`----------------------------------------------------------------*/
static void
parse_assoc_decl (associativity assoc)
{
char *name = NULL;
int prev = 0;
lastprec++; /* Assign a new precedence level, never 0. */
for (;;)
{
token_t t;
int tmp_char = ungetc (skip_white_space (), finput);
if (tmp_char == '%')
return;
if (tmp_char == EOF)
fatal (_("Premature EOF after %s"), token_buffer);
t = lex ();
switch (t)
{
case tok_typename:
name = xstrdup (token_buffer);
break;
case tok_comma:
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);
symval->class = token_sym;
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);
}
break;
case tok_number:
if (prev == tok_identifier)
{
symval->user_token_number = numval;
translations = 1;
}
else
{
complain (_
("invalid text (%s) - number should be after identifier"),
token_buffer);
skip_to_char ('%');
}
break;
case tok_semicolon:
return;
default:
complain (_("unexpected item: %s"), token_buffer);
skip_to_char ('%');
}
prev = t;
}
}
/*--------------------------------------------------------------.
| Copy the union declaration into ATTRS_OBSTACK (and fdefines), |
| where it is made into the definition of YYSTYPE, the type of |
| elements of the parser value stack. |
`--------------------------------------------------------------*/
static void
parse_union_decl (void)
{
int c;
int count = 0;
if (typed)
complain (_("multiple %s declarations"), "%union");
typed = 1;
if (!no_lines_flag)
obstack_fgrow2 (&attrs_obstack, "\n#line %d %s\n",
lineno, quotearg_style (c_quoting_style, infile));
else
obstack_1grow (&attrs_obstack, '\n');
obstack_sgrow (&attrs_obstack, "typedef union");
if (defines_flag)
obstack_sgrow (&defines_obstack, "typedef union");
c = getc (finput);
while (c != EOF)
{
obstack_1grow (&attrs_obstack, c);
if (defines_flag)
obstack_1grow (&defines_obstack, c);
switch (c)
{
case '\n':
lineno++;
break;
case '/':
copy_comment2 (finput, &defines_obstack, &attrs_obstack);
break;
case '{':
count++;
break;
case '}':
if (count == 0)
complain (_("unmatched %s"), "`}'");
count--;
if (count <= 0)
{
obstack_sgrow (&attrs_obstack, " YYSTYPE;\n");
if (defines_flag)
obstack_sgrow (&defines_obstack, " YYSTYPE;\n");
/* JF don't choke on trailing semi */
c = skip_white_space ();
if (c != ';')
ungetc (c, finput);
return;
}
}
c = getc (finput);
}
}
/*-------------------------------------------------------.
| Parse the declaration %expect N which says to expect N |
| shift-reduce conflicts. |
`-------------------------------------------------------*/
static void
parse_expect_decl (void)
{
int c = skip_white_space ();
ungetc (c, finput);
if (!isdigit (c))
complain (_("argument of %%expect is not an integer"));
else
expected_conflicts = read_signed_integer (finput);
}
/*-------------------------------------------------------------------.
| Parse what comes after %thong. the full syntax is |
| |
| %thong <type> token number literal |
| |
| the <type> 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 <type>, if any, from the |
| declaration. The ->user_token_number of the first is SALIAS 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;
struct bucket *symbol;
char *typename = 0;
int usrtoknum;
translations = 1;
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 = SALIAS;
symbol = symval;
token = lex (); /* get number or literal string */
if (token == tok_number)
{
usrtoknum = numval;
token = lex (); /* okay, did number, now get literal */
}
else
usrtoknum = 0;
/* 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--;
}
/*------------------------------------------.
| Parse what comes after %header_extension. |
`------------------------------------------*/
static void
parse_header_extension_decl (void)
{
char buff[32];
if (header_extension)
complain (_("multiple %%header_extension declarations"));
fscanf (finput, "%s", buff);
header_extension = xstrdup (buff);
}
/*------------------------------------------.
| Parse what comes after %source_extension. |
`------------------------------------------*/
static void
parse_source_extension_decl (void)
{
char buff[32];
if (src_extension)
complain (_("multiple %%source_extension declarations"));
fscanf (finput, "%s", buff);
src_extension = xstrdup (buff);
}
/*----------------------------------------------------------------.
| Read from finput until `%%' is seen. Discard the `%%'. Handle |
| any `%' declarations, and copy the contents of any `%{ ... %}' |
| groups to ATTRS_OBSTACK. |
`----------------------------------------------------------------*/
static void
read_declarations (void)
{
int c;
int tok;
for (;;)
{
c = skip_white_space ();
if (c == '%')
{
tok = parse_percent_token ();
switch (tok)
{
case tok_two_percents:
return;
case tok_percent_left_curly:
copy_definition ();
break;
case tok_token:
parse_token_decl (token_sym, nterm_sym);
break;
case tok_nterm:
parse_token_decl (nterm_sym, token_sym);
break;
case tok_type:
parse_type_decl ();
break;
case tok_start:
parse_start_decl ();
break;
case tok_union:
parse_union_decl ();
break;
case tok_expect:
parse_expect_decl ();
break;
case tok_thong:
parse_thong_decl ();
break;
case tok_left:
parse_assoc_decl (left_assoc);
break;
case tok_right:
parse_assoc_decl (right_assoc);
break;
case tok_nonassoc:
parse_assoc_decl (non_assoc);
break;
case tok_hdrext:
break;
case tok_srcext:
parse_source_extension_decl();
break;
case tok_noop:
break;
default:
complain (_("unrecognized: %s"), token_buffer);
skip_to_char ('%');
}
}
else if (c == EOF)
fatal (_("no input grammar"));
else
{
char buf[] = "c";
buf[0] = c;
complain (_("unknown character: %s"), quote (buf));
skip_to_char ('%');
}
}
}
/*-------------------------------------------------------------------.
| Assuming that a `{' has just been seen, copy everything up to the |
| matching `}' into the actions file. STACK_OFFSET is the number of |
| values in the current rule so far, which says where to find `$0' |
| with respect to the top of the stack. |
`-------------------------------------------------------------------*/
static void
copy_action (symbol_list *rule, int stack_offset)
{
int c;
int count;
char buf[4096];
/* offset is always 0 if parser has already popped the stack pointer */
if (semantic_parser)
stack_offset = 0;
sprintf (buf, "\ncase %d:\n", nrules);
obstack_grow (&action_obstack, buf, strlen (buf));
if (!no_lines_flag)
{
sprintf (buf, "#line %d %s\n",
lineno, quotearg_style (c_quoting_style, infile));
obstack_grow (&action_obstack, buf, strlen (buf));
}
obstack_1grow (&action_obstack, '{');
count = 1;
c = getc (finput);
while (count > 0)
{
while (c != '}')
{
switch (c)
{
case '\n':
obstack_1grow (&action_obstack, c);
lineno++;
break;
case '{':
obstack_1grow (&action_obstack, c);
count++;
break;
case '\'':
case '"':
copy_string (finput, &action_obstack, c);
break;
case '/':
copy_comment (finput, &action_obstack);
break;
case '$':
copy_dollar (finput, &action_obstack,
rule, stack_offset);
break;
case '@':
copy_at (finput, &action_obstack,
stack_offset);
break;
case EOF:
fatal (_("unmatched %s"), "`{'");
default:
obstack_1grow (&action_obstack, c);
}
c = getc (finput);
}
/* above loop exits when c is '}' */
if (--count)
{
obstack_1grow (&action_obstack, c);
c = getc (finput);
}
}
obstack_sgrow (&action_obstack, ";\n break;}");
}
/*-------------------------------------------------------------------.
| After `%guard' is seen in the input file, copy the actual guard |
| into the guards file. If the guard is followed by an action, copy |
| that into the actions file. STACK_OFFSET is the number of values |
| in the current rule so far, which says where to find `$0' with |
| respect to the top of the stack, for the simple parser in which |
| the stack is not popped until after the guard is run. |
`-------------------------------------------------------------------*/
static void
copy_guard (symbol_list *rule, int stack_offset)
{
int c;
int count;
int brace_flag = 0;
/* offset is always 0 if parser has already popped the stack pointer */
if (semantic_parser)
stack_offset = 0;
obstack_fgrow1 (&guard_obstack, "\ncase %d:\n", nrules);
if (!no_lines_flag)
obstack_fgrow2 (&guard_obstack, "#line %d %s\n",
lineno, quotearg_style (c_quoting_style, infile));
obstack_1grow (&guard_obstack, '{');
count = 0;
c = getc (finput);
while (brace_flag ? (count > 0) : (c != ';'))
{
switch (c)
{
case '\n':
obstack_1grow (&guard_obstack, c);
lineno++;
break;
case '{':
obstack_1grow (&guard_obstack, c);
brace_flag = 1;
count++;
break;
case '}':
obstack_1grow (&guard_obstack, c);
if (count > 0)
count--;
else
{
complain (_("unmatched %s"), "`}'");
c = getc (finput); /* skip it */
}
break;
case '\'':
case '"':
copy_string (finput, &guard_obstack, c);
break;
case '/':
copy_comment (finput, &guard_obstack);
break;
case '$':
copy_dollar (finput, &guard_obstack, rule, stack_offset);
break;
case '@':
copy_at (finput, &guard_obstack, stack_offset);
break;
case EOF:
fatal ("%s", _("unterminated %guard clause"));
default:
obstack_1grow (&guard_obstack, c);
}
if (c != '}' || count != 0)
c = getc (finput);
}
c = skip_white_space ();
obstack_sgrow (&guard_obstack, ";\n break;}");
if (c == '{')
copy_action (rule, stack_offset);
else if (c == '=')
{
c = getc (finput); /* why not skip_white_space -wjh */
if (c == '{')
copy_action (rule, stack_offset);
}
else
ungetc (c, finput);
}
static void
record_rule_line (void)
{
/* Record each rule's source line number in rline table. */
if (nrules >= rline_allocated)
{
rline_allocated = nrules * 2;
rline = XREALLOC (rline, short, rline_allocated);
}
rline[nrules] = lineno;
}
/*-------------------------------------------------------------------.
| Generate a dummy symbol, a nonterminal, whose name cannot conflict |
| with the user's names. |
`-------------------------------------------------------------------*/
static bucket *
gensym (void)
{
/* Incremented for each generated symbol */
static int gensym_count = 0;
static char buf[256];
bucket *sym;
sprintf (buf, "@%d", ++gensym_count);
token_buffer = buf;
sym = getsym (token_buffer);
sym->class = nterm_sym;
sym->value = nvars++;
return sym;
}
#if 0
/*------------------------------------------------------------------.
| read in a %type declaration and record its information for |
| get_type_name to access. This is unused. It is only called from |
| the #if 0 part of readgram |
`------------------------------------------------------------------*/
static int
get_type (void)
{
int k;
token_t token;
char *name;
token = lex ();
if (token != tok_typename)
{
complain (_("invalid %s declaration"), "%type");
return t;
}
name = xstrdup (token_buffer);
for (;;)
{
token = lex ();
switch (token)
{
case tok_semicolon:
return lex ();
case tok_comma:
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);
break;
default:
return token;
}
}
}
#endif
/*------------------------------------------------------------------.
| Parse the input grammar into a one symbol_list structure. Each |
| rule is represented by a sequence of symbols: the left hand side |
| followed by the contents of the right hand side, followed by a |
| null pointer instead of a symbol to terminate the rule. The next |
| symbol is the lhs of the following rule. |
| |
| All guards and actions are copied out to the appropriate files, |
| labelled by the rule number they apply to. |
`------------------------------------------------------------------*/
static void
readgram (void)
{
token_t t;
bucket *lhs = NULL;
symbol_list *p;
symbol_list *p1;
bucket *bp;
/* Points to first symbol_list of current rule. its symbol is the
lhs of the rule. */
symbol_list *crule;
/* Points to the symbol_list preceding crule. */
symbol_list *crule1;
p1 = NULL;
t = lex ();
while (t != tok_two_percents && t != tok_eof)
{
if (t == tok_identifier || t == tok_bar)
{
int action_flag = 0;
/* Number of symbols in rhs of this rule so far */
int rulelength = 0;
int xactions = 0; /* JF for error checking */
bucket *first_rhs = 0;
if (t == tok_identifier)
{
lhs = symval;
if (!start_flag)
{
startval = lhs;
start_flag = 1;
}
t = lex ();
if (t != tok_colon)
{
complain (_("ill-formed rule: initial symbol not followed by colon"));
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++;
nitems++;
record_rule_line ();
p = XCALLOC (symbol_list, 1);
p->sym = 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->value = nvars;
nvars++;
}
else if (lhs->class == token_sym)
complain (_("rule given for %s, which is a token"), lhs->tag);
/* read the rhs of the rule. */
for (;;)
{
t = lex ();
if (t == tok_prec)
{
t = lex ();
crule->ruleprec = symval;
t = lex ();
}
if (!(t == tok_identifier || t == tok_left_curly))
break;
/* If next token is an identifier, see if a colon follows it.
If one does, exit this rule now. */
if (t == tok_identifier)
{
bucket *ssave;
token_t t1;
ssave = symval;
t1 = lex ();
unlex (t1);
symval = ssave;
if (t1 == tok_colon)
break;
if (!first_rhs) /* JF */
first_rhs = symval;
/* Not followed by colon =>
process as part of this rule's rhs. */
}
/* If we just passed an action, that action was in the middle
of a rule, so make a dummy rule to reduce it to a
non-terminal. */
if (action_flag)
{
bucket *sdummy;
/* 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. */
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++;
nitems++;
record_rule_line ();
p = XCALLOC (symbol_list, 1);
if (crule1)
crule1->next = p;
else
grammar = p;
p->sym = sdummy;
crule1 = XCALLOC (symbol_list, 1);
p->next = crule1;
crule1->next = crule;
/* Insert the dummy generated by that rule into this
rule. */
nitems++;
p = XCALLOC (symbol_list, 1);
p->sym = sdummy;
p1->next = p;
p1 = p;
action_flag = 0;
}
if (t == tok_identifier)
{
nitems++;
p = XCALLOC (symbol_list, 1);
p->sym = symval;
p1->next = p;
p1 = p;
}
else /* handle an action. */
{
copy_action (crule, rulelength);
action_flag = 1;
xactions++; /* JF */
}
rulelength++;
} /* end of read rhs of rule */
/* Put an empty link in the list to mark the end of this rule */
p = XCALLOC (symbol_list, 1);
p1->next = p;
p1 = p;
if (t == tok_prec)
{
complain (_("two @prec's in a row"));
t = lex ();
crule->ruleprec = symval;
t = lex ();
}
if (t == tok_guard)
{
if (!semantic_parser)
complain (_("%%guard present but %%semantic_parser not specified"));
copy_guard (crule, rulelength);
t = lex ();
}
else if (t == tok_left_curly)
{
/* This case never occurs -wjh */
if (action_flag)
complain (_("two actions at end of one rule"));
copy_action (crule, rulelength);
action_flag = 1;
xactions++; /* -wjh */
t = lex ();
}
/* If $$ is being set in default way, report if any type
mismatch. */
else if (!xactions
&& first_rhs && lhs->type_name != first_rhs->type_name)
{
if (lhs->type_name == 0
|| first_rhs->type_name == 0
|| strcmp (lhs->type_name, first_rhs->type_name))
complain (_("type clash (`%s' `%s') on default action"),
lhs->type_name ? lhs->type_name : "",
first_rhs->type_name ? first_rhs->type_name : "");
}
/* Warn if there is no default for $$ but we need one. */
else if (!xactions && !first_rhs && lhs->type_name != 0)
complain (_("empty rule for typed nonterminal, and no action"));
if (t == tok_semicolon)
t = lex ();
}
#if 0
/* these things can appear as alternatives to rules. */
/* NO, they cannot.
a) none of the documentation allows them
b) most of them scan forward until finding a next %
thus they may swallow lots of intervening rules
*/
else if (t == tok_token)
{
parse_token_decl (token_sym, nterm_sym);
t = lex ();
}
else if (t == tok_nterm)
{
parse_token_decl (nterm_sym, token_sym);
t = lex ();
}
else if (t == tok_type)
{
t = get_type ();
}
else if (t == tok_union)
{
parse_union_decl ();
t = lex ();
}
else if (t == tok_expect)
{
parse_expect_decl ();
t = lex ();
}
else if (t == tok_start)
{
parse_start_decl ();
t = lex ();
}
#endif
else
{
complain (_("invalid input: %s"), quote (token_buffer));
t = lex ();
}
}
/* grammar has been read. Do some checking */
if (nsyms > MAXSHORT)
fatal (_("too many symbols (tokens plus nonterminals); maximum %d"),
MAXSHORT);
if (nrules == 0)
fatal (_("no rules in the input grammar"));
/* JF put out same default YYSTYPE as YACC does */
if (typed == 0
&& !value_components_used)
{
/* We used to use `unsigned long' as YYSTYPE on MSDOS,
but it seems better to be consistent.
Most programs should declare their own type anyway. */
obstack_sgrow (&attrs_obstack,
"#ifndef YYSTYPE\n#define YYSTYPE int\n#endif\n");
if (defines_flag)
obstack_sgrow (&defines_obstack, "\
#ifndef YYSTYPE\n\
# define YYSTYPE int\n\
#endif\n");
}
/* Report any undefined symbols and consider them nonterminals. */
for (bp = firstsymbol; bp; bp = bp->next)
if (bp->class == unknown_sym)
{
complain (_
("symbol %s is used, but is not defined as a token and has no rules"),
bp->tag);
bp->class = nterm_sym;
bp->value = nvars++;
}
ntokens = nsyms - nvars;
}
/*--------------------------------------------------------------.
| For named tokens, but not literal ones, define the name. The |
| value is the user token number. |
`--------------------------------------------------------------*/
static void
output_token_defines (struct obstack *oout)
{
bucket *bp;
char *cp, *symbol;
char c;
for (bp = firstsymbol; bp; bp = bp->next)
{
symbol = bp->tag; /* get symbol */
if (bp->value >= ntokens)
continue;
if (bp->user_token_number == SALIAS)
continue;
if ('\'' == *symbol)
continue; /* skip literal character */
if (bp == errtoken)
continue; /* skip error token */
if ('\"' == *symbol)
{
/* use literal string only if given a symbol with an alias */
if (bp->alias)
symbol = bp->alias->tag;
else
continue;
}
/* Don't #define nonliteral tokens whose names contain periods. */
cp = symbol;
while ((c = *cp++) && c != '.');
if (c != '\0')
continue;
obstack_fgrow2 (oout, "#define\t%s\t%d\n",
symbol,
(translations ? bp->user_token_number : bp->value));
if (semantic_parser)
obstack_fgrow2 (oout, "#define\tT%s\t%d\n", symbol, bp->value);
}
obstack_1grow (oout, '\n');
}
/*------------------------------------------------------------------.
| Assign symbol numbers, and write definition of token names into |
| FDEFINES. Set up vectors TAGS and SPREC of names and precedences |
| of symbols. |
`------------------------------------------------------------------*/
static void
packsymbols (void)
{
bucket *bp;
int tokno = 1;
int i;
int last_user_token_number;
static char DOLLAR[] = "$";
/* int lossage = 0; JF set but not used */
tags = XCALLOC (char *, nsyms + 1);
tags[0] = DOLLAR;
user_toknums = XCALLOC (short, nsyms + 1);
user_toknums[0] = 0;
sprec = XCALLOC (short, nsyms);
sassoc = XCALLOC (short, nsyms);
max_user_token_number = 256;
last_user_token_number = 256;
for (bp = firstsymbol; bp; bp = bp->next)
{
if (bp->class == nterm_sym)
{
bp->value += ntokens;
}
else if (bp->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 (bp->value == 0)
bp->value = bp->alias->value = tokno++;
if (bp->prec != bp->alias->prec)
{
if (bp->prec != 0 && bp->alias->prec != 0
&& bp->user_token_number == SALIAS)
complain (_("conflicting precedences for %s and %s"),
bp->tag, bp->alias->tag);
if (bp->prec != 0)
bp->alias->prec = bp->prec;
else
bp->prec = bp->alias->prec;
}
if (bp->assoc != bp->alias->assoc)
{
if (bp->assoc != 0 && bp->alias->assoc != 0
&& bp->user_token_number == SALIAS)
complain (_("conflicting assoc values for %s and %s"),
bp->tag, bp->alias->tag);
if (bp->assoc != 0)
bp->alias->assoc = bp->assoc;
else
bp->assoc = bp->alias->assoc;
}
if (bp->user_token_number == SALIAS)
continue; /* do not do processing below for SALIASs */
}
else /* bp->class == token_sym */
{
bp->value = tokno++;
}
if (bp->class == token_sym)
{
if (translations && !(bp->user_token_number))
bp->user_token_number = ++last_user_token_number;
if (bp->user_token_number > max_user_token_number)
max_user_token_number = bp->user_token_number;
}
tags[bp->value] = bp->tag;
user_toknums[bp->value] = bp->user_token_number;
sprec[bp->value] = bp->prec;
sassoc[bp->value] = bp->assoc;
}
if (translations)
{
int j;
token_translations = XCALLOC (short, 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 (j = 0; j <= max_user_token_number; j++)
token_translations[j] = 2;
for (bp = firstsymbol; bp; bp = bp->next)
{
if (bp->value >= ntokens)
continue; /* non-terminal */
if (bp->user_token_number == SALIAS)
continue;
if (token_translations[bp->user_token_number] != 2)
complain (_("tokens %s and %s both assigned number %d"),
tags[token_translations[bp->user_token_number]],
bp->tag, bp->user_token_number);
token_translations[bp->user_token_number] = bp->value;
}
}
error_token_number = errtoken->value;
if (!no_parser_flag)
output_token_defines (&table_obstack);
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->value;
if (defines_flag)
{
output_token_defines (&defines_obstack);
if (!pure_parser)
{
if (spec_name_prefix)
obstack_fgrow1 (&defines_obstack, "\nextern YYSTYPE %slval;\n",
spec_name_prefix);
else
obstack_sgrow (&defines_obstack,
"\nextern YYSTYPE yylval;\n");
}
if (semantic_parser)
for (i = ntokens; i < nsyms; i++)
{
/* don't make these for dummy nonterminals made by gensym. */
if (*tags[i] != '@')
obstack_fgrow2 (&defines_obstack,
"#define\tNT%s\t%d\n", tags[i], i);
}
#if 0
/* `fdefines' is now a temporary file, so we need to copy its
contents in `done', so we can't close it here. */
fclose (fdefines);
fdefines = NULL;
#endif
}
}
/*---------------------------------------------------------------.
| Convert the rules into the representation using RRHS, RLHS and |
| RITEMS. |
`---------------------------------------------------------------*/
static void
packgram (void)
{
int itemno;
int ruleno;
symbol_list *p;
bucket *ruleprec;
ritem = XCALLOC (short, nitems + 1);
rlhs = XCALLOC (short, nrules) - 1;
rrhs = XCALLOC (short, nrules) - 1;
rprec = XCALLOC (short, nrules) - 1;
rprecsym = XCALLOC (short, nrules) - 1;
rassoc = XCALLOC (short, nrules) - 1;
itemno = 0;
ruleno = 1;
p = grammar;
while (p)
{
rlhs[ruleno] = p->sym->value;
rrhs[ruleno] = itemno;
ruleprec = p->ruleprec;
p = p->next;
while (p && p->sym)
{
ritem[itemno++] = p->sym->value;
/* A rule gets by default the precedence and associativity
of the last token in it. */
if (p->sym->class == token_sym)
{
rprec[ruleno] = p->sym->prec;
rassoc[ruleno] = p->sym->assoc;
}
if (p)
p = p->next;
}
/* If this rule has a %prec,
the specified symbol's precedence replaces the default. */
if (ruleprec)
{
rprec[ruleno] = ruleprec->prec;
rassoc[ruleno] = ruleprec->assoc;
rprecsym[ruleno] = ruleprec->value;
}
ritem[itemno++] = -ruleno;
ruleno++;
if (p)
p = p->next;
}
ritem[itemno] = 0;
}
/*-------------------------------------------------------------------.
| Read in the grammar specification and record it in the format |
| described in gram.h. All guards are copied into the GUARD_OBSTACK |
| and all actions into ACTION_OBSTACK, in each case forming the body |
| of a C function (YYGUARD or YYACTION) which contains a switch |
| statement to decide which guard or action to execute. |
`-------------------------------------------------------------------*/
void
reader (void)
{
start_flag = 0;
startval = NULL; /* start symbol not specified yet. */
#if 0
/* initially assume token number translation not needed. */
translations = 0;
#endif
/* Nowadays translations is always set to 1, since we give `error' a
user-token-number to satisfy the Posix demand for YYERRCODE==256.
*/
translations = 1;
nsyms = 1;
nvars = 0;
nrules = 0;
nitems = 0;
rline_allocated = 10;
rline = XCALLOC (short, rline_allocated);
typed = 0;
lastprec = 0;
semantic_parser = 0;
pure_parser = 0;
grammar = NULL;
init_lex ();
lineno = 1;
/* Initialize the symbol table. */
tabinit ();
/* Construct the error token */
errtoken = getsym ("error");
errtoken->class = token_sym;
errtoken->user_token_number = 256; /* Value specified by POSIX. */
/* Construct a token that represents all undefined literal tokens.
It is always token number 2. */
undeftoken = getsym ("$undefined.");
undeftoken->class = token_sym;
undeftoken->user_token_number = 2;
/* Read the declaration section. Copy %{ ... %} groups to
TABLE_OBSTACK and FDEFINES file. Also notice any %token, %left,
etc. found there. */
obstack_1grow (&table_obstack, '\n');
obstack_fgrow3 (&table_obstack, "\
/* %s, made from %s\n\
by GNU bison %s. */\n\
\n",
no_parser_flag ? "Bison-generated parse tables" : "A Bison parser",
infile, VERSION);
obstack_sgrow (&table_obstack,
"#define YYBISON 1 /* Identify Bison output. */\n\n");
read_declarations ();
/* Start writing the guard and action files, if they are needed. */
output_headers ();
/* Read in the grammar, build grammar in list form. Write out
guards and actions. */
readgram ();
/* Now we know whether we need the line-number stack. If we do,
write its type into the .tab.h file. */
if (defines_flag)
reader_output_yylsp (&defines_obstack);
/* Write closing delimiters for actions and guards. */
output_trailers ();
if (locations_flag)
obstack_sgrow (&table_obstack, "#define YYLSP_NEEDED 1\n\n");
/* Assign the symbols their symbol numbers. Write #defines for the
token symbols into FDEFINES if requested. */
packsymbols ();
/* Convert the grammar into the format described in gram.h. */
packgram ();
/* Free the symbol table data structure since symbols are now all
referred to by symbol number. */
free_symtab ();
}
/*------------------------------------------------------------------.
| Define YYLTYPE. Cannot be in the skeleton since we might have to |
| output it in the headers if --defines is used. |
`------------------------------------------------------------------*/
void
reader_output_yylsp (struct obstack *oout)
{
if (locations_flag)
obstack_sgrow (oout, "\
\n\
#ifndef YYLTYPE\n\
typedef struct yyltype\n\
{\n\
int first_line;\n\
int first_column;\n\
\n\
int last_line;\n\
int last_column;\n\
} yyltype;\n\
\n\
# define YYLTYPE yyltype\n\
#endif\n\
\n");
}
Reference in New Issue View Git Blame Copy Permalink