/* perly.c
*
- * Copyright (c) 2004, 2005, 2006 Larry Wall and others
+ * Copyright (c) 2004, 2005, 2006, 2007, 2008 by Larry Wall and others
*
* You may distribute under the terms of either the GNU General Public
* License or the Artistic License, as specified in the README file.
typedef short int yytype_int16;
typedef signed char yysigned_char;
-typedef struct {
- YYSTYPE val; /* semantic value */
- short state;
- AV *comppad; /* value of PL_comppad when this value was created */
-#ifdef DEBUGGING
- const char *name; /* token/rule name for -Dpv */
-#endif
-} yy_stack_frame;
-
-typedef struct {
- int stack_size;
- int reduce_len; /* XXX integrate with yylen ? */
- yy_stack_frame *ps; /* current stack frame */
- yy_stack_frame stack[1]; /* will actually be as many as needed */
-} yy_parser;
-
-
+/* YYINITDEPTH -- initial size of the parser's stacks. */
+#define YYINITDEPTH 200
#ifdef DEBUGGING
# define YYDEBUG 1
# define YYSIZE_T size_t
-#define YYEMPTY (-2)
#define YYEOF 0
#define YYTERROR 1
{
const yy_stack_frame *ps, *min;
- min = parser->ps - 8;
- if (min <= &parser->stack[0])
- min = &parser->stack[0] + 1;
+ min = parser->ps - 8 + 1;
+ if (min <= parser->stack)
+ min = parser->stack + 1;
PerlIO_printf(Perl_debug_log, "\nindex:");
for (ps = min; ps <= parser->ps; ps++)
- PerlIO_printf(Perl_debug_log, " %8d", ps - &parser->stack[0]);
+ PerlIO_printf(Perl_debug_log, " %8d", (int)(ps - parser->stack));
PerlIO_printf(Perl_debug_log, "\nstate:");
for (ps = min; ps <= parser->ps; ps++)
# define YY_REDUCE_PRINT(Rule)
#endif /* !DEBUGGING */
-
-/* YYINITDEPTH -- initial size of the parser's stacks. */
-#define YYINITDEPTH 200
-
/* called during cleanup (via SAVEDESTRUCTOR_X) to free any items on the
* parse stack, thus avoiding leaks if we die */
static void
-S_clear_yystack(pTHX_ const void *p)
+S_clear_yystack(pTHX_ const yy_parser *parser)
{
- yy_parser *parser = (yy_parser*) SvPVX((SV*)p);
yy_stack_frame *ps = parser->ps;
- int i;
+ int i = 0;
- if (ps == &parser->stack[0])
+ if (!parser->stack)
return;
YYDPRINTF ((Perl_debug_log, "clearing the parse stack\n"));
- /* Freeing ops on the stack, and the op_latefree/op_latefreed flags:
+ /* Freeing ops on the stack, and the op_latefree / op_latefreed /
+ * op_attached flags:
*
* When we pop tokens off the stack during error recovery, or when
* we pop all the tokens off the stack after a die during a shift or
- * reduce (ie Perl_croak somewhere in yylex(), or in one of the
- * newFOO() functions, then its possible that some of these tokens are
+ * reduce (i.e. Perl_croak somewhere in yylex() or in one of the
+ * newFOO() functions), then it's possible that some of these tokens are
* of type opval, pointing to an OP. All these ops are orphans; each is
* its own miniature subtree that has not yet been attached to a
- * larger tree. In this case, we shoould clearly free the op (making
- * sure, for each op we free thyat we have PL_comppad pointing to the
+ * larger tree. In this case, we should clearly free the op (making
+ * sure, for each op we free that we have PL_comppad pointing to the
* right place for freeing any SVs attached to the op in threaded
* builds.
*
- * However, there is a particular problem if we die in newFOO called
+ * However, there is a particular problem if we die in newFOO() called
* by a reducing action; e.g.
*
* foo : bar baz boz
* { $$ = newFOO($1,$2,$3) }
*
* where
- * OP *newFOO { .... croak .... }
+ * OP *newFOO { ....; if (...) croak; .... }
*
* In this case, when we come to clean bar baz and boz off the stack,
* we don't know whether newFOO() has already:
* * freed them
- * * left them as it
+ * * left them as is
* * attached them to part of a larger tree
+ * * attached them to PL_compcv
+ * * attached them to PL_compcv then freed it (as in BEGIN {die } )
*
* To get round this problem, we set the flag op_latefree on every op
* that gets pushed onto the parser stack. If op_free() sees this
* reduced, call op_free with op_latefree=1. This ensures that all ops
* hanging off these op are freed, but the reducing ops themselces are
* just undefed. Then we set op_latefreed=0 on *all* ops on the stack
- * and free them. A little though should convince you that this
- * two-part approach to the reducing ops should handle all three cases
- * above safely.
- */
+ * and free them. A little thought should convince you that this
+ * two-part approach to the reducing ops should handle the first three
+ * cases above safely.
+ *
+ * In the case of attaching to PL_compcv (currently just newATTRSUB
+ * does this), then we set the op_attached flag on the op that has
+ * been so attached, then avoid doing the final op_free during
+ * cleanup, on the assumption that it will happen (or has already
+ * happened) when PL_compcv is freed.
+ *
+ * Note this is fairly fragile mechanism. A more robust approach
+ * would be to use two of these flag bits as 2-bit reference count
+ * field for each op, indicating whether it is pointed to from:
+ * * a parent op
+ * * the parser stack
+ * * a CV
+ * but this would involve reworking all code (core and external) that
+ * manipulate op trees.
+ *
+ * XXX DAPM 17/1/07 I've decided its too fragile for now, and so have
+ * disabled it */
- /* free any reducing ops (1st pass) */
+#define DISABLE_STACK_FREE
+
+
+#ifdef DISABLE_STACK_FREE
+ for (i=0; i< parser->yylen; i++) {
+ SvREFCNT_dec(ps[-i].compcv);
+ }
+ ps -= parser->yylen;
+#else
+ /* clear any reducing ops (1st pass) */
- for (i=0; i< parser->reduce_len; i++) {
+ for (i=0; i< parser->yylen; i++) {
+ LEAVE_SCOPE(ps[-i].savestack_ix);
if (yy_type_tab[yystos[ps[-i].state]] == toketype_opval
&& ps[-i].val.opval) {
- if (ps[-i].comppad != PL_comppad) {
- PAD_RESTORE_LOCAL(ps[-i].comppad);
+ if ( ! (ps[-i].val.opval->op_attached
+ && !ps[-i].val.opval->op_latefreed))
+ {
+ if (ps[-i].compcv != PL_compcv) {
+ PL_compcv = ps[-i].compcv;
+ PAD_SET_CUR_NOSAVE(CvPADLIST(PL_compcv), 1);
+ }
+ op_free(ps[-i].val.opval);
}
- op_free(ps[-i].val.opval);
}
}
+#endif
/* now free whole the stack, including the just-reduced ops */
- while (ps > &parser->stack[0]) {
+ while (ps > parser->stack) {
+ LEAVE_SCOPE(ps->savestack_ix);
if (yy_type_tab[yystos[ps->state]] == toketype_opval
&& ps->val.opval)
{
- if (ps->comppad != PL_comppad) {
- PAD_RESTORE_LOCAL(ps->comppad);
+ if (ps->compcv != PL_compcv) {
+ PL_compcv = ps->compcv;
+ PAD_SET_CUR_NOSAVE(CvPADLIST(PL_compcv), 1);
}
YYDPRINTF ((Perl_debug_log, "(freeing op)\n"));
+#ifndef DISABLE_STACK_FREE
ps->val.opval->op_latefree = 0;
- op_free(ps->val.opval);
+ if (!(ps->val.opval->op_attached && !ps->val.opval->op_latefreed))
+#endif
+ op_free(ps->val.opval);
}
+ SvREFCNT_dec(ps->compcv);
ps--;
}
-}
+ Safefree(parser->stack);
+}
/*----------.
int
#ifdef PERL_IN_MADLY_C
-Perl_madparse (pTHX)
+Perl_madparse (pTHX_ int gramtype)
#else
-Perl_yyparse (pTHX)
+Perl_yyparse (pTHX_ int gramtype)
#endif
{
dVAR;
- int yychar; /* The lookahead symbol. */
- YYSTYPE yylval; /* The semantic value of the lookahead symbol. */
- int yynerrs; /* Number of syntax errors so far. */
register int yystate;
register int yyn;
int yyresult;
- /* Number of tokens to shift before error messages enabled. */
- int yyerrstatus;
/* Lookahead token as an internal (translated) token number. */
int yytoken = 0;
- SV *parser_sv; /* SV whose PVX holds the parser object */
- yy_parser *parser; /* the parser object */
+ register yy_parser *parser; /* the parser object */
register yy_stack_frame *ps; /* current parser stack frame */
#define YYPOPSTACK parser->ps = --ps
#define YYPUSHSTACK parser->ps = ++ps
- /* The variables used to return semantic value and location from the
- action routines. */
+ /* The variable used to return semantic value and location from the
+ action routines: ie $$. */
YYSTYPE yyval;
- /* When reducing, the number of symbols on the RHS of the reduced
- rule. */
- int yylen;
-
#ifndef PERL_IN_MADLY_C
# ifdef PERL_MAD
if (PL_madskills)
- return madparse();
+ return madparse(gramtype);
# endif
#endif
YYDPRINTF ((Perl_debug_log, "Starting parse\n"));
- ENTER; /* force stack free before we return */
- SAVEVPTR(PL_yycharp);
- SAVEVPTR(PL_yylvalp);
- PL_yycharp = &yychar; /* so PL_yyerror() can access it */
- PL_yylvalp = &yylval; /* so various functions in toke.c can access it */
+ parser = PL_parser;
- parser_sv = newSV(sizeof(yy_parser)
- + (YYINITDEPTH-1) * sizeof(yy_stack_frame));
- SAVEFREESV(parser_sv);
- parser = (yy_parser*) SvPVX(parser_sv);
- ps = (yy_stack_frame*) &parser->stack[0];
- parser->ps = ps;
+ ENTER; /* force parser state cleanup/restoration before we return */
+ SAVEPPTR(parser->yylval.pval);
+ SAVEINT(parser->yychar);
+ SAVEINT(parser->yyerrstatus);
+ SAVEINT(parser->stack_size);
+ SAVEINT(parser->yylen);
+ SAVEVPTR(parser->stack);
+ SAVEVPTR(parser->ps);
+ /* initialise state for this parse */
+ parser->yychar = gramtype;
+ parser->yyerrstatus = 0;
parser->stack_size = YYINITDEPTH;
-
- /* cleanup the parse stack on premature exit */
- SAVEDESTRUCTOR_X(S_clear_yystack, (void*) parser_sv);
-
-
+ parser->yylen = 0;
+ Newx(parser->stack, YYINITDEPTH, yy_stack_frame);
+ ps = parser->ps = parser->stack;
ps->state = 0;
- yyerrstatus = 0;
- yynerrs = 0;
- yychar = YYEMPTY; /* Cause a token to be read. */
+ SAVEDESTRUCTOR_X(S_clear_yystack, parser);
/*------------------------------------------------------------.
| yynewstate -- Push a new state, which is found in yystate. |
YYDPRINTF ((Perl_debug_log, "Entering state %d\n", yystate));
+#ifndef DISABLE_STACK_FREE
if (yy_type_tab[yystos[yystate]] == toketype_opval && ps->val.opval) {
ps->val.opval->op_latefree = 1;
ps->val.opval->op_latefreed = 0;
}
+#endif
- parser->reduce_len = 0;
+ parser->yylen = 0;
{
- size_t size = ps - &parser->stack[0] + 1;
+ size_t size = ps - parser->stack + 1;
/* grow the stack? We always leave 1 spare slot,
* in case of a '' -> 'foo' reduction */
- if (size >= parser->stack_size - 1) {
+ if (size >= (size_t)parser->stack_size - 1) {
/* this will croak on insufficient memory */
parser->stack_size *= 2;
- parser = (yy_parser*) SvGROW(parser_sv, sizeof(yy_parser)
- + (parser->stack_size-1) * sizeof(yy_stack_frame));
-
- /* readdress any pointers into realloced parser object */
- ps = parser->ps = &parser->stack[0] + size -1;
+ Renew(parser->stack, parser->stack_size, yy_stack_frame);
+ ps = parser->ps = parser->stack + size -1;
YYDPRINTF((Perl_debug_log,
"parser stack size increased to %lu frames\n",
/* Not known => get a lookahead token if don't already have one. */
/* YYCHAR is either YYEMPTY or YYEOF or a valid lookahead symbol. */
- if (yychar == YYEMPTY) {
+ if (parser->yychar == YYEMPTY) {
YYDPRINTF ((Perl_debug_log, "Reading a token: "));
#ifdef PERL_IN_MADLY_C
- yychar = PL_madskills ? madlex() : yylex();
+ parser->yychar = PL_madskills ? madlex() : yylex();
#else
- yychar = yylex();
+ parser->yychar = yylex();
#endif
# ifdef EBCDIC
- if (yychar >= 0 && yychar < 255) {
- yychar = NATIVE_TO_ASCII(yychar);
+ if (parser->yychar >= 0 && parser->yychar < 255) {
+ parser->yychar = NATIVE_TO_ASCII(parser->yychar);
}
# endif
}
- if (yychar <= YYEOF) {
- yychar = yytoken = YYEOF;
+ if (parser->yychar <= YYEOF) {
+ parser->yychar = yytoken = YYEOF;
YYDPRINTF ((Perl_debug_log, "Now at end of input.\n"));
}
else {
- yytoken = YYTRANSLATE (yychar);
- YYDSYMPRINTF ("Next token is", yytoken, &yylval);
+ yytoken = YYTRANSLATE (parser->yychar);
+ YYDSYMPRINTF ("Next token is", yytoken, &parser->yylval);
}
/* If the proper action on seeing token YYTOKEN is to reduce or to
YYDPRINTF ((Perl_debug_log, "Shifting token %s, ", yytname[yytoken]));
/* Discard the token being shifted unless it is eof. */
- if (yychar != YYEOF)
- yychar = YYEMPTY;
+ if (parser->yychar != YYEOF)
+ parser->yychar = YYEMPTY;
YYPUSHSTACK;
ps->state = yyn;
- ps->val = yylval;
- ps->comppad = PL_comppad;
+ ps->val = parser->yylval;
+ ps->compcv = (CV*)SvREFCNT_inc(PL_compcv);
+ ps->savestack_ix = PL_savestack_ix;
#ifdef DEBUGGING
ps->name = (const char *)(yytname[yytoken]);
#endif
/* Count tokens shifted since error; after three, turn off error
status. */
- if (yyerrstatus)
- yyerrstatus--;
+ if (parser->yyerrstatus)
+ parser->yyerrstatus--;
goto yynewstate;
`-----------------------------*/
yyreduce:
/* yyn is the number of a rule to reduce with. */
- yylen = yyr2[yyn];
+ parser->yylen = yyr2[yyn];
/* If YYLEN is nonzero, implement the default value of the action:
"$$ = $1".
users should not rely upon it. Assigning to YYVAL
unconditionally makes the parser a bit smaller, and it avoids a
GCC warning that YYVAL may be used uninitialized. */
- yyval = ps[1-yylen].val;
+ yyval = ps[1-parser->yylen].val;
YY_STACK_PRINT(parser);
YY_REDUCE_PRINT (yyn);
- /* if we croak during a reduce, this many tokens need special clean up */
- parser->reduce_len = yylen;
-
switch (yyn) {
* freed; the rest need the flag resetting */
{
int i;
- for (i=0; i< yylen; i++) {
+ for (i=0; i< parser->yylen; i++) {
+#ifndef DISABLE_STACK_FREE
if (yy_type_tab[yystos[ps[-i].state]] == toketype_opval
&& ps[-i].val.opval)
{
if (ps[-i].val.opval->op_latefreed)
op_free(ps[-i].val.opval);
}
+#endif
+ SvREFCNT_dec(ps[-i].compcv);
}
}
- parser->ps = ps -= (yylen-1);
+ parser->ps = ps -= (parser->yylen-1);
/* Now shift the result of the reduction. Determine what state
that goes to, based on the state we popped back to and the rule
number reduced by. */
ps->val = yyval;
- ps->comppad = PL_comppad;
+ ps->compcv = (CV*)SvREFCNT_inc(PL_compcv);
+ ps->savestack_ix = PL_savestack_ix;
#ifdef DEBUGGING
ps->name = (const char *)(yytname [yyr1[yyn]]);
#endif
`------------------------------------*/
yyerrlab:
/* If not already recovering from an error, report this error. */
- if (!yyerrstatus) {
- ++yynerrs;
+ if (!parser->yyerrstatus) {
yyerror ("syntax error");
}
- if (yyerrstatus == 3) {
+ if (parser->yyerrstatus == 3) {
/* If just tried and failed to reuse lookahead token after an
error, discard it. */
/* Return failure if at end of input. */
- if (yychar == YYEOF) {
+ if (parser->yychar == YYEOF) {
/* Pop the error token. */
+ SvREFCNT_dec(ps->compcv);
YYPOPSTACK;
/* Pop the rest of the stack. */
- while (ps > &parser->stack[0]) {
+ while (ps > parser->stack) {
YYDSYMPRINTF ("Error: popping", yystos[ps->state], &ps->val);
+ LEAVE_SCOPE(ps->savestack_ix);
if (yy_type_tab[yystos[ps->state]] == toketype_opval
&& ps->val.opval)
{
YYDPRINTF ((Perl_debug_log, "(freeing op)\n"));
- if (ps->comppad != PL_comppad) {
- PAD_RESTORE_LOCAL(ps->comppad);
+ if (ps->compcv != PL_compcv) {
+ PL_compcv = ps->compcv;
+ PAD_SET_CUR_NOSAVE(CvPADLIST(PL_compcv), 1);
}
ps->val.opval->op_latefree = 0;
op_free(ps->val.opval);
}
+ SvREFCNT_dec(ps->compcv);
YYPOPSTACK;
}
YYABORT;
}
- YYDSYMPRINTF ("Error: discarding", yytoken, &yylval);
- yychar = YYEMPTY;
+ YYDSYMPRINTF ("Error: discarding", yytoken, &parser->yylval);
+ if (yy_type_tab[yytoken] == toketype_opval)
+ op_free(parser->yylval.opval);
+ parser->yychar = YYEMPTY;
}
| yyerrlab1 -- error raised explicitly by an action. |
`----------------------------------------------------*/
yyerrlab1:
- yyerrstatus = 3; /* Each real token shifted decrements this. */
+ parser->yyerrstatus = 3; /* Each real token shifted decrements this. */
for (;;) {
yyn = yypact[yystate];
}
/* Pop the current state because it cannot handle the error token. */
- if (ps == &parser->stack[0])
+ if (ps == parser->stack)
YYABORT;
YYDSYMPRINTF ("Error: popping", yystos[ps->state], &ps->val);
+ LEAVE_SCOPE(ps->savestack_ix);
if (yy_type_tab[yystos[ps->state]] == toketype_opval && ps->val.opval) {
YYDPRINTF ((Perl_debug_log, "(freeing op)\n"));
- if (ps->comppad != PL_comppad) {
- PAD_RESTORE_LOCAL(ps->comppad);
+ if (ps->compcv != PL_compcv) {
+ PL_compcv = ps->compcv;
+ PAD_SET_CUR_NOSAVE(CvPADLIST(PL_compcv), 1);
}
ps->val.opval->op_latefree = 0;
op_free(ps->val.opval);
}
+ SvREFCNT_dec(ps->compcv);
YYPOPSTACK;
yystate = ps->state;
YYPUSHSTACK;
ps->state = yyn;
- ps->val = yylval;
- ps->comppad = PL_comppad;
+ ps->val = parser->yylval;
+ ps->compcv = (CV*)SvREFCNT_inc(PL_compcv);
+ ps->savestack_ix = PL_savestack_ix;
#ifdef DEBUGGING
ps->name ="<err>";
#endif
`-------------------------------------*/
yyacceptlab:
yyresult = 0;
- parser->ps = &parser->stack[0]; /* disable cleanup */
+ for (ps=parser->ps; ps > parser->stack; ps--) {
+ SvREFCNT_dec(ps->compcv);
+ }
+ parser->ps = parser->stack; /* disable cleanup */
goto yyreturn;
/*-----------------------------------.
goto yyreturn;
yyreturn:
- LEAVE; /* force stack free before we return */
+ LEAVE; /* force parser stack cleanup before we return */
return yyresult;
}
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