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Encapsulate code properties and related functionality for the various

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destructors, printers, and actions into a code_props structure and
interface.  This patch merely implements code_props in scan-code.h and
scan-code.l.  Future patches will rewrite other modules to use it.
Discussed starting at
<http://lists.gnu.org/archive/html/bison-patches/2006-11/msg00020.html>.
* src/location.h (EMPTY_LOCATION_INIT): Define so that it's easier to
consistently initialize const structs that have an empty location
field.
* src/location.c (empty_location): Initialize with EMPTY_LOCATION_INIT
to ensure consistency.
* src/scan-code.h (code_props): New structure.
(code_props_none_init, CODE_PROPS_NONE_INIT, code_props_none): New
function, macro, and const global variable for initializing a
code_props with no code.
(code_props_plain_init, code_props_symbol_action_init,
code_props_rule_action_init, code_props_translate_code): The rest of
the new code_props functional interface.  Among other things, the init
functions set the code_props kind field so that
code_props_translate_code will know whether to behave like
translate_symbol_action, translate_rule_action, or translate_code.
These old translate functions must remain until all other modules are
updated to use the new code_props interface.
(code_scanner_last_string_free): New function similar to
gram_scanner_last_string_free.
(code_scanner_free): Add documentation.
* src/scan-code.l: Implement the new interface.
(code_lex): Make it static, add a code_props* argument, and remove the
rule argument.
(last_string): New static global similar to the one in scan-gram.l.
(SC_RULE_ACTION): Update to use the code_props* argument to code_lex
instead of rule.
(SC_SYMBOL_ACTION): For $$, set the is_value_used member of the
code_props since Bison may one day use this information for destructors
and printers.
(<*><<EOF>>): Use STRING_FINISH so that last_string is set.
(handle_action_dollar): Use symbol_list_n_get and set used flag
directly since symbol_list_n_used_set is removed.
(translate_action): Add a code_props* argument and remove the rule,
action, and location arguments.  Pass the code_props* on to code_lex.
(translate_rule_action, translate_symbol_action, translate_code):
Rewrite as wrappers around the new code_props interface.
* src/symlist.h, src/symlist.c (symbol_list_n_used_set): Remove since
it would eventually need to break the encapsulation of code_props.
This commit is contained in:
Joel E. Denny
2007-01-02 23:31:14 +00:00
parent 9603498306
commit 28e52c0d62
7 changed files with 307 additions and 54 deletions
Download Patch File Download Diff File Expand all files Collapse all files

47
ChangeLog
View File

@@ -1,3 +1,50 @@
2007-01-02 Joel E. Denny <jdenny@ces.clemson.edu>
Encapsulate code properties and related functionality for the various
destructors, printers, and actions into a code_props structure and
interface. This patch merely implements code_props in scan-code.h and
scan-code.l. Future patches will rewrite other modules to use it.
Discussed starting at
<http://lists.gnu.org/archive/html/bison-patches/2006-11/msg00020.html>.
* src/location.h (EMPTY_LOCATION_INIT): Define so that it's easier to
consistently initialize const structs that have an empty location
field.
* src/location.c (empty_location): Initialize with EMPTY_LOCATION_INIT
to ensure consistency.
* src/scan-code.h (code_props): New structure.
(code_props_none_init, CODE_PROPS_NONE_INIT, code_props_none): New
function, macro, and const global variable for initializing a
code_props with no code.
(code_props_plain_init, code_props_symbol_action_init,
code_props_rule_action_init, code_props_translate_code): The rest of
the new code_props functional interface. Among other things, the init
functions set the code_props kind field so that
code_props_translate_code will know whether to behave like
translate_symbol_action, translate_rule_action, or translate_code.
These old translate functions must remain until all other modules are
updated to use the new code_props interface.
(code_scanner_last_string_free): New function similar to
gram_scanner_last_string_free.
(code_scanner_free): Add documentation.
* src/scan-code.l: Implement the new interface.
(code_lex): Make it static, add a code_props* argument, and remove the
rule argument.
(last_string): New static global similar to the one in scan-gram.l.
(SC_RULE_ACTION): Update to use the code_props* argument to code_lex
instead of rule.
(SC_SYMBOL_ACTION): For $$, set the is_value_used member of the
code_props since Bison may one day use this information for destructors
and printers.
(<*><<EOF>>): Use STRING_FINISH so that last_string is set.
(handle_action_dollar): Use symbol_list_n_get and set used flag
directly since symbol_list_n_used_set is removed.
(translate_action): Add a code_props* argument and remove the rule,
action, and location arguments. Pass the code_props* on to code_lex.
(translate_rule_action, translate_symbol_action, translate_code):
Rewrite as wrappers around the new code_props interface.
* src/symlist.h, src/symlist.c (symbol_list_n_used_set): Remove since
it would eventually need to break the encapsulation of code_props.
2007-01-01 Joel E. Denny <jdenny@ces.clemson.edu>
* etc/.cvsignore: New.

4
src/location.c
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@@ -1,5 +1,5 @@
/* Locations for Bison
Copyright (C) 2002, 2005, 2006 Free Software Foundation, Inc.
Copyright (C) 2002, 2005, 2006, 2007 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
@@ -27,7 +27,7 @@
#include "complain.h"
#include "location.h"
location const empty_location;
location const empty_location = EMPTY_LOCATION_INIT;
/* If BUF is null, add BUFSIZE (which in this case must be less than
INT_MAX) to COLUMN; otherwise, add mbsnwidth (BUF, BUFSIZE, 0) to

3
src/location.h
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@@ -1,5 +1,5 @@
/* Locations for Bison
Copyright (C) 2002, 2004, 2005, 2006 Free Software Foundation, Inc.
Copyright (C) 2002, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
@@ -71,6 +71,7 @@ typedef struct
#define YYLTYPE location
#define EMPTY_LOCATION_INIT {{NULL, 0, 0}, {NULL, 0, 0}}
extern location const empty_location;
/* Set *LOC and adjust scanner cursor to account for token TOKEN of

148
src/scan-code.h
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@@ -1,6 +1,6 @@
/* Bison Action Scanner
/* Bison code properties structure and scanner.
Copyright (C) 2006 Free Software Foundation, Inc.
Copyright (C) 2006, 2007 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
@@ -24,13 +24,149 @@
# define SCAN_CODE_H_
# include "location.h"
# include "symlist.h"
/* 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. */
struct symbol_list;
/**
* Keeps track of the maximum number of semantic values to the left of a handle
* (those referenced by $0, $-1, etc.) that are required by the semantic
* actions of this grammar.
*/
extern int max_left_semantic_context;
/**
* A code passage captured from the grammar file and possibly translated,
* and/or properties associated with such a code passage. Don't break
* encapsulation by modifying the fields directly. Use the provided interface
* functions.
*/
typedef struct code_props {
/** Set by the init functions. */
enum {
CODE_PROPS_NONE, CODE_PROPS_PLAIN,
CODE_PROPS_SYMBOL_ACTION, CODE_PROPS_RULE_ACTION
} kind;
/** \c NULL iff \c code_props::kind is \c CODE_PROPS_NONE. */
char const *code;
/** Undefined iff \c code_props::code is \c NULL. */
location location;
/**
* \c false iff either:
* - \c code_props_translate_code has never previously been invoked for
* the \c code_props that would contain the code passage associated
* with \c self. (That \c code_props is not the same as this one if this
* one is for a RHS \c symbol_list node. Instead, it's the \c code_props
* for the LHS symbol of the same rule.)
* - \c code_props_translate_code has been invoked for that \c code_props,
* but the symbol value associated with this \c code_props was not
* referenced in the code passage.
*/
bool is_value_used;
/** \c NULL iff \c code_props::kind is not \c CODE_PROPS_RULE_ACTION. */
struct symbol_list *rule;
} code_props;
/**
* \pre
* - <tt>self != NULL</tt>.
* \post
* - \c self has been overwritten to contain no code.
*/
void code_props_none_init (code_props *self);
/** Equivalent to \c code_props_none_init. */
#define CODE_PROPS_NONE_INIT \
{CODE_PROPS_NONE, NULL, EMPTY_LOCATION_INIT, false, NULL}
/** Initialized by \c CODE_PROPS_NONE_INIT with no further modification. */
extern code_props const code_props_none;
/**
* \pre
* - <tt>self != NULL</tt>.
* - <tt>code != NULL</tt>.
* - \c code is an untranslated code passage containing no Bison escapes.
* - \c code was extracted from the grammar file at \c code_loc.
* \post
* - \c self has been overwritten to represent the specified plain code
* passage.
* - \c self will become invalid if the caller frees \c code before invoking
* \c code_props_translate_code on \c self.
*/
void code_props_plain_init (code_props *self, char const *code,
location code_loc);
/**
* \pre
* - <tt>self != NULL</tt>.
* - <tt>code != NULL</tt>.
* - \c code is an untranslated code passage. The only Bison escapes it
* might contain are $$ and \@$, referring to a single symbol.
* - \c code was extracted from the grammar file at \c code_loc.
* \post
* - \c self has been overwritten to represent the specified symbol action.
* - \c self will become invalid if the caller frees \c code before invoking
* \c code_props_translate_code on \c self.
*/
void code_props_symbol_action_init (code_props *self, char const *code,
location code_loc);
/**
* \pre
* - <tt>self != NULL</tt>.
* - <tt>code != NULL</tt>.
* - <tt>rule != NULL</tt>.
* - \c code is the untranslated action of the rule for which \c rule is the
* LHS node. Thus, \c code possibly contains Bison escapes such as $$, $1,
* $2, etc referring to the values of the rule.
* - \c code was extracted from the grammar file at \c code_loc.
* \post
* - \c self has been overwritten to represent the specified rule action.
* - \c self does not claim responsibility for the memory of \c rule.
* - \c self will become invalid if:
* - The caller frees \c code before invoking \c code_props_translate_code
* on \c self.
* - The caller frees \c rule.
*/
void code_props_rule_action_init (code_props *self, char const *code,
location code_loc, struct symbol_list *rule);
/**
* \pre
* - If there's a code passage contained in \c self and it contains Bison
* escapes, all grammar declarations have already been parsed as they may
* affect warnings and complaints issued here.
* \post
* - All M4-special symbols and Bison escapes have been translated in
* \c self->code.
* - <tt>self->code != self->code\@pre</tt> unless
* <tt>self->code\@pre = NULL</tt>.
*/
void code_props_translate_code (code_props *self);
/**
* \pre
* - None.
* \post
* - The dynamic memory allocated by the previous invocation of
* \c code_props_translate_code (if any) was freed. The \c code_props
* instance for which \c code_props_translate_code was invoked is now
* invalid.
*/
void code_scanner_last_string_free (void);
/**
* \pre
* - None.
* \post
* - All dynamic memory allocated during any previous invocations of
* \c code_props_translate_code, \c translate_rule_action,
* \c translate_symbol_action, and \c translate_code has been freed. All
* \c code_props instances may now be invalid.
*/
void code_scanner_free (void);
/* The action of the rule R contains $$, $1 etc. referring to the values

140
src/scan-code.l
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@@ -1,6 +1,6 @@
/* Bison Action Scanner -*- C -*-
Copyright (C) 2006 Free Software Foundation, Inc.
Copyright (C) 2006, 2007 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
@@ -39,10 +39,11 @@
#include <quote.h>
#include "scan-code.h"
#include "symlist.h"
/* The current calling start condition: SC_RULE_ACTION or
SC_SYMBOL_ACTION. */
# define YY_DECL char *code_lex (int sc_context, symbol_list *rule)
# 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);
@@ -53,6 +54,9 @@ static void handle_action_at (symbol_list *rule, char *cp, location at_loc);
static location the_location;
static location *loc = &the_location;
/* A string representing the most recent translation. */
static char *last_string;
/* True if an untyped $$ or $n was seen. */
static bool untyped_var_seen;
%}
@@ -151,8 +155,12 @@ splice (\\[ \f\t\v]*\n)*
<SC_RULE_ACTION>
{
"$"("<"{tag}">")?(-?[0-9]+|"$") handle_action_dollar (rule, yytext, *loc);
"@"(-?[0-9]+|"$") handle_action_at (rule, yytext, *loc);
"$"("<"{tag}">")?(-?[0-9]+|"$") {
handle_action_dollar (self->rule, yytext, *loc);
}
"@"(-?[0-9]+|"$") {
handle_action_at (self->rule, yytext, *loc);
}
"$" {
warn_at (*loc, _("stray `$'"));
@@ -190,7 +198,10 @@ splice (\\[ \f\t\v]*\n)*
<SC_SYMBOL_ACTION>
{
"$$" obstack_sgrow (&obstack_for_string, "]b4_dollar_dollar[");
"$$" {
obstack_sgrow (&obstack_for_string, "]b4_dollar_dollar[");
self->is_value_used = true;
}
"@$" obstack_sgrow (&obstack_for_string, "]b4_at_dollar[");
}
@@ -215,8 +226,8 @@ splice (\\[ \f\t\v]*\n)*
/* End of processing. */
<*><<EOF>> {
obstack_1grow (&obstack_for_string, '\0');
return obstack_finish (&obstack_for_string);
STRING_FINISH;
return last_string;
}
%%
@@ -238,7 +249,7 @@ int max_left_semantic_context = 0;
static void
handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
{
const char *type_name = NULL;
char const *type_name = NULL;
char *cp = text + 1;
symbol_list *effective_rule;
int effective_rule_length;
@@ -321,7 +332,8 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
obstack_fgrow3 (&obstack_for_string,
"]b4_rhs_value(%d, %d, [%s])[",
effective_rule_length, n, type_name);
symbol_list_n_used_set (effective_rule, n, true);
if (n > 0)
symbol_list_n_get (effective_rule, n)->used = true;
}
else
complain_at (dollar_loc, _("integer out of range: %s"), quote (text));
@@ -368,12 +380,11 @@ handle_action_at (symbol_list *rule, char *text, location at_loc)
| Initialize the scanner. |
`-------------------------*/
/* Translate the dollars and ats in \a a, whose location is \a l. The
translation is for \a rule, in the context \a sc_context
/* 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 (int sc_context, symbol_list *rule, char const *a, location l)
translate_action (code_props *self, int sc_context)
{
char *res;
static bool initialized = false;
@@ -384,36 +395,82 @@ translate_action (int sc_context, symbol_list *rule, char const *a, location l)
initialized = true;
}
loc->start = loc->end = l.start;
yy_switch_to_buffer (yy_scan_string (a));
res = code_lex (sc_context, rule);
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;
}
char const *
translate_rule_action (symbol_list *rule)
/*------------------------------------------------------------------------.
| Implementation of the public interface as documented in "scan-code.h". |
`------------------------------------------------------------------------*/
void
code_props_none_init (code_props *self)
{
return translate_action (SC_RULE_ACTION, rule, rule->action,
rule->action_location);
*self = code_props_none;
}
char const *
translate_symbol_action (char const *a, location l)
code_props const code_props_none = CODE_PROPS_NONE_INIT;
void
code_props_plain_init (code_props *self, char const *code, location code_loc)
{
return translate_action (SC_SYMBOL_ACTION, NULL, a, l);
self->kind = CODE_PROPS_PLAIN;
self->code = code;
self->location = code_loc;
self->is_value_used = false;
self->rule = NULL;
}
char const *
translate_code (char const *a, location l)
void
code_props_symbol_action_init (code_props *self, char const *code,
location code_loc)
{
return translate_action (INITIAL, NULL, a, l);
self->kind = CODE_PROPS_SYMBOL_ACTION;
self->code = code;
self->location = code_loc;
self->is_value_used = false;
self->rule = NULL;
}
/*-----------------------------------------------.
| Free all the memory allocated to the scanner. |
`-----------------------------------------------*/
void
code_props_rule_action_init (code_props *self, char const *code,
location code_loc, symbol_list *rule)
{
self->kind = CODE_PROPS_RULE_ACTION;
self->code = code;
self->location = code_loc;
self->is_value_used = false;
self->rule = rule;
}
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)
@@ -422,3 +479,30 @@ code_scanner_free (void)
/* Reclaim Flex's buffers. */
yylex_destroy ();
}
char const *
translate_rule_action (symbol_list *rule)
{
code_props cp;
code_props_rule_action_init (&cp, rule->action, rule->action_location, rule);
code_props_translate_code (&cp);
return cp.code;
}
char const *
translate_symbol_action (char const *a, location l)
{
code_props cp;
code_props_symbol_action_init (&cp, a, l);
code_props_translate_code (&cp);
return cp.code;
}
char const *
translate_code (char const *a, location l)
{
code_props cp;
code_props_plain_init (&cp, a, l);
code_props_translate_code (&cp);
return cp.code;
}

14
src/symlist.c
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@@ -1,6 +1,6 @@
/* Lists of symbols for Bison
Copyright (C) 2002, 2005, 2006 Free Software Foundation, Inc.
Copyright (C) 2002, 2005, 2006, 2007 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
@@ -207,18 +207,6 @@ symbol_list_n_type_name_get (symbol_list *l, location loc, int n)
}
/*--------------------------------------.
| The item N in symbol list L is USED. |
`--------------------------------------*/
void
symbol_list_n_used_set (symbol_list *l, int n, bool used)
{
l = symbol_list_n_get (l, n);
if (l)
l->used = used;
}
void
symbol_list_destructor_set (symbol_list *node, const char *destructor,
location loc)

5
src/symlist.h
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@@ -1,6 +1,6 @@
/* Lists of symbols for Bison
Copyright (C) 2002, 2005, 2006 Free Software Foundation, Inc.
Copyright (C) 2002, 2005, 2006, 2007 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
@@ -106,9 +106,6 @@ symbol_list *symbol_list_n_get (symbol_list *l, int n);
symbol N in rule RULE. */
uniqstr symbol_list_n_type_name_get (symbol_list *l, location loc, int n);
/** The item \c n in symbol list \c l is \c used. */
void symbol_list_n_used_set (symbol_list *l, int n, bool used);
/** Set the \c \%destructor for \c node as \c destructor at \c loc. */
void symbol_list_destructor_set (symbol_list *node, const char *destructor,
location loc);