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/* st.c -- Implementation File (module.c template V1.0)
Copyright (C) 1995 Free Software Foundation, Inc.
Contributed by James Craig Burley (burley@gnu.ai.mit.edu).
This file is part of GNU Fortran.
GNU Fortran 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.
GNU Fortran 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 GNU Fortran; see the file COPYING. If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.
Related Modules:
None
Description:
The high-level input level to statement handling for the rest of the
FFE. ffest_first is the first state for the lexer to invoke to start
a statement. A statement normally starts with a NUMBER token (to indicate
a label def) followed by a NAME token (to indicate what kind of statement
it is), though of course the NUMBER token may be omitted. ffest_first
gathers the first NAME token and returns a state of ffest_second_,
where the trailing underscore means "internal to ffest" and thus outside
users should not depend on this. ffest_second_ then looks at the second
token in conjunction with the first, decides what possible statements are
meant, and tries each possible statement in turn, from most likely to
least likely. A successful attempt currently is recorded, and further
successful attempts by other possibilities raise an assertion error in
ffest_confirmed (this is to detect ambiguities). A failure in an
attempt is signaled by calling ffest_ffebad_start; this results in the
next token sent by ffest_save_ (the intermediary when more than one
possible statement exists) being EOS to shut down processing and the next
possibility tried.
When all possibilities have been tried, the successful one is retried with
inhibition turned off (FALSE) as reported by ffest_is_inhibited(). If
there is no successful one, the first one is retried so the user gets to
see the error messages.
In the future, after syntactic bugs have been reasonably shaken out and
ambiguities thus detected, the first successful possibility will be
enabled (inhibited goes FALSE) as soon as it confirms success by calling
ffest_confirmed, thus retrying the possibility will not be necessary.
The only complication in all this is that expression handling is
happening while possibilities are inhibited. It is up to the expression
handler, conceptually, to not make any changes to its knowledge base for
variable names and so on when inhibited that cannot be undone if
the current possibility fails (shuts down via ffest_ffebad_start). In
fact, this business is handled not be ffeexpr, but by lower levels.
ffesta functions serve only to provide information used in syntactic
processing of possible statements, and thus may not make changes to the
knowledge base for variables and such.
ffestb functions perform the syntactic analysis for possible statements,
and thus again may not make changes to the knowledge base except under the
auspices of ffeexpr and its subordinates, changes which can be undone when
necessary.
ffestc functions perform the semantic analysis for the chosen statement,
and thus may change the knowledge base as necessary since they are invoked
by ffestb functions only after a given statement is confirmed and
enabled. Note, however, that a few ffestc functions (identified by
their statement names rather than grammar numbers) indicate valid forms
that are, outside of any context, ambiguous, such as ELSE WHERE and
PRIVATE; these functions should make a quick decision as to what is
intended and dispatch to the appropriate specific ffestc function.
ffestd functions actually implement statements. When called, the
statement is considered valid and is either an executable statement or
a nonexecutable statement with direct-output results. For example, CALL,
GOTO, and assignment statements pass through ffestd because they are
executable; DATA statements pass through because they map directly to the
output file (or at least might so map); ENTRY statements also pass through
because they essentially affect code generation in an immediate way;
whereas INTEGER, SAVE, and SUBROUTINE statements do not go through
ffestd functions because they merely update the knowledge base.
Modifications:
*/
/* Include files. */
#include "proj.h"
#include "st.h"
#include "bad.h"
#include "lex.h"
#include "sta.h"
#include "stb.h"
#include "stc.h"
#include "std.h"
#include "ste.h"
#include "stp.h"
#include "str.h"
#include "sts.h"
#include "stt.h"
#include "stu.h"
#include "stv.h"
#include "stw.h"
/* Externals defined here. */
/* Simple definitions and enumerations. */
/* Internal typedefs. */
/* Private include files. */
/* Internal structure definitions. */
/* Static objects accessed by functions in this module. */
/* Static functions (internal). */
/* Internal macros. */
/* ffest_confirmed -- Confirm current possibility as only one
ffest_confirmed();
Sets the confirmation flag. During debugging for ambiguous constructs,
asserts that the confirmation flag for a previous possibility has not
yet been set. */
void
ffest_confirmed ()
{
ffesta_confirmed ();
}
/* ffest_eof -- End of (non-INCLUDEd) source file
ffest_eof();
Call after piping tokens through ffest_first, where the most recent
token sent through must be EOS.
20-Feb-91 JCB 1.1
Put new EOF token in ffesta_tokens[0], not NULL, because too much
code expects something there for error reporting and the like. Also,
do basically the same things ffest_second and ffesta_zero do for
processing a statement (make and destroy pools, et cetera). */
void
ffest_eof ()
{
ffesta_eof ();
}
/* ffest_ffebad_here_current_stmt -- ffebad_here with ptr to current stmt
ffest_ffebad_here_current_stmt(0);
Outsiders can call this fn if they have no more convenient place to
point to (via a token or pair of ffewhere objects) and they know a
current, useful statement is being evaluted by ffest (i.e. they are
being called from ffestb, ffestc, ffestd, ... functions). */
void
ffest_ffebad_here_current_stmt (ffebadIndex i)
{
ffesta_ffebad_here_current_stmt (i);
}
/* ffest_ffebad_here_doiter -- Calls ffebad_here with ptr to DO iter var
ffesymbol s;
// call ffebad_start first, of course.
ffest_ffebad_here_doiter(0,s);
// call ffebad_finish afterwards, naturally.
Searches the stack of blocks backwards for a DO loop that has s
as its iteration variable, then calls ffebad_here with pointers to
that particular reference to the variable. Crashes if the DO loop
can't be found. */
void
ffest_ffebad_here_doiter (ffebadIndex i, ffesymbol s)
{
ffestc_ffebad_here_doiter (i, s);
}
/* ffest_ffebad_start -- Start a possibly inhibited error report
if (ffest_ffebad_start(FFEBAD_SOME_ERROR))
{
ffebad_here, ffebad_string ...;
ffebad_finish();
}
Call if the error might indicate that ffest is evaluating the wrong
statement form, instead of calling ffebad_start directly. If ffest
is choosing between forms, it will return FALSE, send an EOS/SEMICOLON
token through as the next token (if the current one isn't already one
of those), and try another possible form. Otherwise, ffebad_start is
called with the argument and TRUE returned. */
bool
ffest_ffebad_start (ffebad errnum)
{
return ffesta_ffebad_start (errnum);
}
/* ffest_first -- Parse the first token in a statement
return ffest_first; // to lexer. */
ffelexHandler
ffest_first (ffelexToken t)
{
return ffesta_first (t);
}
/* ffest_init_0 -- Initialize for entire image invocation
ffest_init_0();
Call just once per invocation of the compiler (not once per invocation
of the front end).
Gets memory for the list of possibles once and for all, since this
list never gets larger than a certain size (FFEST_maxPOSSIBLES_)
and is not particularly large. Initializes the array of pointers to
this list. Initializes the executable and nonexecutable lists. */
void
ffest_init_0 ()
{
ffesta_init_0 ();
ffestb_init_0 ();
ffestc_init_0 ();
ffestd_init_0 ();
ffeste_init_0 ();
ffestp_init_0 ();
ffestr_init_0 ();
ffests_init_0 ();
ffestt_init_0 ();
ffestu_init_0 ();
ffestv_init_0 ();
ffestw_init_0 ();
}
/* ffest_init_1 -- Initialize for entire image invocation
ffest_init_1();
Call just once per invocation of the compiler (not once per invocation
of the front end).
Gets memory for the list of possibles once and for all, since this
list never gets larger than a certain size (FFEST_maxPOSSIBLES_)
and is not particularly large. Initializes the array of pointers to
this list. Initializes the executable and nonexecutable lists. */
void
ffest_init_1 ()
{
ffesta_init_1 ();
ffestb_init_1 ();
ffestc_init_1 ();
ffestd_init_1 ();
ffeste_init_1 ();
ffestp_init_1 ();
ffestr_init_1 ();
ffests_init_1 ();
ffestt_init_1 ();
ffestu_init_1 ();
ffestv_init_1 ();
ffestw_init_1 ();
}
/* ffest_init_2 -- Initialize for entire image invocation
ffest_init_2();
Call just once per invocation of the compiler (not once per invocation
of the front end).
Gets memory for the list of possibles once and for all, since this
list never gets larger than a certain size (FFEST_maxPOSSIBLES_)
and is not particularly large. Initializes the array of pointers to
this list. Initializes the executable and nonexecutable lists. */
void
ffest_init_2 ()
{
ffesta_init_2 ();
ffestb_init_2 ();
ffestc_init_2 ();
ffestd_init_2 ();
ffeste_init_2 ();
ffestp_init_2 ();
ffestr_init_2 ();
ffests_init_2 ();
ffestt_init_2 ();
ffestu_init_2 ();
ffestv_init_2 ();
ffestw_init_2 ();
}
/* ffest_init_3 -- Initialize for any program unit
ffest_init_3(); */
void
ffest_init_3 ()
{
ffesta_init_3 ();
ffestb_init_3 ();
ffestc_init_3 ();
ffestd_init_3 ();
ffeste_init_3 ();
ffestp_init_3 ();
ffestr_init_3 ();
ffests_init_3 ();
ffestt_init_3 ();
ffestu_init_3 ();
ffestv_init_3 ();
ffestw_init_3 ();
ffestw_display_state ();
}
/* ffest_init_4 -- Initialize for statement functions
ffest_init_4(); */
void
ffest_init_4 ()
{
ffesta_init_4 ();
ffestb_init_4 ();
ffestc_init_4 ();
ffestd_init_4 ();
ffeste_init_4 ();
ffestp_init_4 ();
ffestr_init_4 ();
ffests_init_4 ();
ffestt_init_4 ();
ffestu_init_4 ();
ffestv_init_4 ();
ffestw_init_4 ();
}
/* Test whether ENTRY statement is valid.
Returns TRUE if current program unit is known to be FUNCTION or SUBROUTINE.
Else returns FALSE. */
bool
ffest_is_entry_valid ()
{
return ffesta_is_entry_valid;
}
/* ffest_is_inhibited -- Test whether the current possibility is inhibited
if (!ffest_is_inhibited())
// implement the statement.
Just make sure the current possibility has been confirmed. If anyone
really needs to test whether the current possibility is inhibited prior
to confirming it, that indicates a need to begin statement processing
before it is certain that the given possibility is indeed the statement
to be processed. As of this writing, there does not appear to be such
a need. If there is, then when confirming a statement would normally
immediately disable the inhibition (whereas currently we leave the
confirmed statement disabled until we've tried the other possibilities,
to check for ambiguities), we must check to see if the possibility has
already tested for inhibition prior to confirmation and, if so, maintain
inhibition until the end of the statement (which may be forced right
away) and then rerun the entire statement from the beginning. Otherwise,
initial calls to ffestb functions won't have been made, but subsequent
calls (after confirmation) will, which is wrong. Of course, this all
applies only to those statements implemented via multiple calls to
ffestb, although if a statement requiring only a single ffestb call
tested for inhibition prior to confirmation, it would likely mean that
the ffestb call would be completely dropped without this mechanism. */
bool
ffest_is_inhibited ()
{
return ffesta_is_inhibited ();
}
/* ffest_seen_first_exec -- Test whether first executable stmt has been seen
if (ffest_seen_first_exec())
// No more spec stmts can be seen.
In a case where, say, the first statement is PARAMETER(A)=B, FALSE
will be returned while the PARAMETER statement is being run, and TRUE
will be returned if it doesn't confirm and the assignment statement
is being run. */
bool
ffest_seen_first_exec ()
{
return ffesta_seen_first_exec;
}
/* Shut down current parsing possibility, but without bothering the
user with a diagnostic if we're not inhibited. */
void
ffest_shutdown ()
{
ffesta_shutdown ();
}
/* ffest_sym_end_transition -- Update symbol info just before end of unit
ffesymbol s;
ffest_sym_end_transition(s); */
ffesymbol
ffest_sym_end_transition (ffesymbol s)
{
return ffestu_sym_end_transition (s);
}
/* ffest_sym_exec_transition -- Update symbol just before first exec stmt
ffesymbol s;
ffest_sym_exec_transition(s); */
ffesymbol
ffest_sym_exec_transition (ffesymbol s)
{
return ffestu_sym_exec_transition (s);
}
/* ffest_terminate_0 -- Terminate for entire image invocation
ffest_terminate_0(); */
void
ffest_terminate_0 ()
{
ffesta_terminate_0 ();
ffestb_terminate_0 ();
ffestc_terminate_0 ();
ffestd_terminate_0 ();
ffeste_terminate_0 ();
ffestp_terminate_0 ();
ffestr_terminate_0 ();
ffests_terminate_0 ();
ffestt_terminate_0 ();
ffestu_terminate_0 ();
ffestv_terminate_0 ();
ffestw_terminate_0 ();
}
/* ffest_terminate_1 -- Terminate for source file
ffest_terminate_1(); */
void
ffest_terminate_1 ()
{
ffesta_terminate_1 ();
ffestb_terminate_1 ();
ffestc_terminate_1 ();
ffestd_terminate_1 ();
ffeste_terminate_1 ();
ffestp_terminate_1 ();
ffestr_terminate_1 ();
ffests_terminate_1 ();
ffestt_terminate_1 ();
ffestu_terminate_1 ();
ffestv_terminate_1 ();
ffestw_terminate_1 ();
}
/* ffest_terminate_2 -- Terminate for outer program unit
ffest_terminate_2(); */
void
ffest_terminate_2 ()
{
ffesta_terminate_2 ();
ffestb_terminate_2 ();
ffestc_terminate_2 ();
ffestd_terminate_2 ();
ffeste_terminate_2 ();
ffestp_terminate_2 ();
ffestr_terminate_2 ();
ffests_terminate_2 ();
ffestt_terminate_2 ();
ffestu_terminate_2 ();
ffestv_terminate_2 ();
ffestw_terminate_2 ();
}
/* ffest_terminate_3 -- Terminate for any program unit
ffest_terminate_3(); */
void
ffest_terminate_3 ()
{
ffesta_terminate_3 ();
ffestb_terminate_3 ();
ffestc_terminate_3 ();
ffestd_terminate_3 ();
ffeste_terminate_3 ();
ffestp_terminate_3 ();
ffestr_terminate_3 ();
ffests_terminate_3 ();
ffestt_terminate_3 ();
ffestu_terminate_3 ();
ffestv_terminate_3 ();
ffestw_terminate_3 ();
}
/* ffest_terminate_4 -- Terminate for statement functions
ffest_terminate_4(); */
void
ffest_terminate_4 ()
{
ffesta_terminate_4 ();
ffestb_terminate_4 ();
ffestc_terminate_4 ();
ffestd_terminate_4 ();
ffeste_terminate_4 ();
ffestp_terminate_4 ();
ffestr_terminate_4 ();
ffests_terminate_4 ();
ffestt_terminate_4 ();
ffestu_terminate_4 ();
ffestv_terminate_4 ();
ffestw_terminate_4 ();
}
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