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/* front-end compiler for vmgen example
Copyright (C) 2001,2002,2003,2007 Free Software Foundation, Inc.
This file is part of Gforth.
Gforth is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation, either version 3
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see http://www.gnu.org/licenses/.
*/
/* I use yacc/bison here not because I think it's the best tool for
the job, but because it's widely available and popular; it's also
(barely) adequate for this job. */
%{
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "mini.h"
/* BB_BOUNDARY is needed on basic blocks without a preceding VM branch */
#define BB_BOUNDARY (last_compiled = NULL, /* suppress peephole opt */ \
block_insert(vmcodep)) /* for accurate profiling */
Inst *vm_prim;
Inst *vmcodep;
FILE *vm_out;
int vm_debug;
void yyerror(char *s)
{
#if 1
/* for pure flex call */
fprintf(stderr, "%s: %s\n", program_name, s);
#else
/* lex or flex -l supports yylineno */
fprintf (stderr, "%s: %d: %s\n", program_name, yylineno, s);
#endif
}
#include "mini-gen.i"
void gen_main_end(void)
{
gen_call(&vmcodep, func_addr("main"), func_calladjust("main"));
gen_end(&vmcodep);
BB_BOUNDARY; /* for profiling; see comment in mini.vmg:end */
}
int locals=0;
int nonparams=0;
int yylex();
%}
%token FUNC RETURN END VAR IF THEN ELSE WHILE DO BECOMES PRINT NUM IDENT
%union {
long num;
char *string;
Inst *instp;
}
%type <string> IDENT;
%type <num> NUM;
%type <instp> elsepart;
%%
program: program function
| ;
function: FUNC IDENT { locals=0; nonparams=0; } '(' params ')'
vars { insert_func($2,vmcodep,locals,nonparams); }
stats RETURN expr ';'
END FUNC ';' { gen_return(&vmcodep, -adjust(locals)); }
;
params: IDENT ',' { insert_local($1); } params
| IDENT { insert_local($1); }
| ;
vars: vars VAR IDENT ';' { insert_local($3); nonparams++; }
| ;
stats: stats stat ';'
| ;
stat: IF expr THEN { gen_zbranch(&vmcodep, 0); $<instp>$ = vmcodep; }
stats { $<instp>$ = $<instp>4; }
elsepart END IF { BB_BOUNDARY; $<instp>7[-1] = (Inst)vmcodep; }
| WHILE { BB_BOUNDARY; $<instp>$ = vmcodep; }
expr DO { gen_zbranch(&vmcodep, 0); $<instp>$ = vmcodep; }
stats END WHILE { gen_branch(&vmcodep, $<instp>2); $<instp>5[-1] = (Inst)vmcodep; }
| IDENT BECOMES expr { gen_storelocal(&vmcodep, var_offset($1)); }
| PRINT expr { gen_print(&vmcodep); }
| expr { gen_drop(&vmcodep); }
;
elsepart: ELSE { gen_branch(&vmcodep, 0); $<instp>$ = vmcodep; $<instp>0[-1] = (Inst)vmcodep; }
stats { $$ = $<instp>2; }
| { $$ = $<instp>0; }
;
expr: term '+' term { gen_add(&vmcodep); }
| term '-' term { gen_sub(&vmcodep); }
| term '*' term { gen_mul(&vmcodep); }
| term '&' term { gen_and(&vmcodep); }
| term '|' term { gen_or(&vmcodep); }
| term '<' term { gen_lessthan(&vmcodep); }
| term '=' term { gen_equals(&vmcodep); }
| '!' term { gen_not(&vmcodep); }
| '-' term { gen_negate(&vmcodep); }
| term
;
term: '(' expr ')'
| IDENT '(' args ')' { gen_call(&vmcodep, func_addr($1), func_calladjust($1)); }
| IDENT { gen_loadlocal(&vmcodep, var_offset($1)); }
| NUM { gen_lit(&vmcodep, $1); }
;
/* missing: argument counting and checking against called function */
args: expr ',' args
| expr
| ;
%%
int yywrap(void)
{
return 1;
}
#include "lex.yy.c"
|
