mawk/code.c

/********************************************
code.c
copyright 1991-93, Michael D. Brennan

This is a source file for mawk, an implementation of
the AWK programming language.

Mawk is distributed without warranty under the terms of
the GNU General Public License, version 2, 1991.
********************************************/

/*
 * $MawkId: code.c,v 1.3 2010/01/31 22:17:18 tom Exp $
 * @Log: code.c,v @
 * Revision 1.6  1995/06/18  19:42:13  mike
 * Remove some redundant declarations and add some prototypes
 *
 * Revision 1.5  1995/06/09  23:21:36  mike
 * make sure there is an execution block in case user defines function,
 * but no pattern-action pairs
 *
 * Revision 1.4  1995/03/08  00:06:22  mike
 * add a pointer cast
 *
 * Revision 1.3  1994/10/08  19:15:29  mike
 * remove SM_DOS
 *
 * Revision 1.2  1993/07/07  00:07:38  mike
 * more work on 1.2
 *
 * Revision 1.1.1.1  1993/07/03	 18:58:10  mike
 * move source to cvs
 *
 * Revision 5.4	 1993/01/14  13:11:11  mike
 * code2() -> xcode2()
 *
 * Revision 5.3	 1993/01/09  20:15:35  mike
 * code_pop checks if the resolve_list needs relocation
 *
 * Revision 5.2	 1993/01/07  02:50:33  mike
 * relative vs absolute code
 *
 * Revision 5.1	 1991/12/05  07:55:43  brennan
 * 1.1 pre-release
 *
 */

/*  code.c  */

#include "mawk.h"
#include "code.h"
#include "init.h"
#include "jmp.h"
#include "field.h"

static CODEBLOCK *new_code(void);

CODEBLOCK active_code;

CODEBLOCK *main_code_p, *begin_code_p, *end_code_p;

INST *begin_start, *main_start, *end_start;
unsigned begin_size, main_size;

INST *execution_start = 0;

/* grow the active code */
void
code_grow(void)
{
    unsigned oldsize = (unsigned) (code_limit - code_base);
    unsigned newsize = PAGESZ + oldsize;
    unsigned delta = (unsigned) (code_ptr - code_base);

    if (code_ptr > code_limit)
	bozo("CODEWARN is too small");

    code_base = (INST *)
	zrealloc(code_base, INST_BYTES(oldsize),
		 INST_BYTES(newsize));
    code_limit = code_base + newsize;
    code_warn = code_limit - CODEWARN;
    code_ptr = code_base + delta;
}

/* shrinks executable code that's done to its final size */
INST *
code_shrink(CODEBLOCK * p, unsigned *sizep)
{

    unsigned oldsize = INST_BYTES(p->limit - p->base);
    unsigned newsize = INST_BYTES(p->ptr - p->base);
    INST *retval;

    *sizep = newsize;

    retval = (INST *) zrealloc(p->base, oldsize, newsize);
    ZFREE(p);
    return retval;
}

/* code an op and a pointer in the active_code */
void
xcode2(int op, PTR ptr)
{
    register INST *p = code_ptr + 2;

    if (p >= code_warn) {
	code_grow();
	p = code_ptr + 2;
    }

    p[-2].op = op;
    p[-1].ptr = ptr;
    code_ptr = p;
}

/* code two ops in the active_code */
void
code2op(int x, int y)
{
    register INST *p = code_ptr + 2;

    if (p >= code_warn) {
	code_grow();
	p = code_ptr + 2;
    }

    p[-2].op = x;
    p[-1].op = y;
    code_ptr = p;
}

void
code_init(void)
{
    main_code_p = new_code();

    active_code = *main_code_p;
    code1(_OMAIN);
}

/* final code relocation
   set_code() as in set concrete */
void
set_code(void)
{
    /* set the main code which is active_code */
    if (end_code_p || code_offset > 1) {
	int gl_offset = code_offset;

	if (NR_flag)
	    code2op(OL_GL_NR, _HALT);
	else
	    code2op(OL_GL, _HALT);

	*main_code_p = active_code;
	main_start = code_shrink(main_code_p, &main_size);
	next_label = main_start + gl_offset;
	execution_start = main_start;
    } else {			/* only BEGIN */
	zfree(code_base, INST_BYTES(PAGESZ));
	ZFREE(main_code_p);
    }

    /* set the END code */
    if (end_code_p) {
	unsigned dummy;

	active_code = *end_code_p;
	code2op(_EXIT0, _HALT);
	*end_code_p = active_code;
	end_start = code_shrink(end_code_p, &dummy);
    }

    /* set the BEGIN code */
    if (begin_code_p) {
	active_code = *begin_code_p;
	if (main_start)
	    code2op(_JMAIN, _HALT);
	else
	    code2op(_EXIT0, _HALT);
	*begin_code_p = active_code;
	begin_start = code_shrink(begin_code_p, &begin_size);

	execution_start = begin_start;
    }

    if (!execution_start) {
	/* program had functions but no pattern-action bodies */
	execution_start = begin_start = (INST *) zmalloc(2 * sizeof(INST));
	execution_start[0].op = _EXIT0;
	execution_start[1].op = _HALT;
    }
}

void
dump_code(void)
{
    fdump();			/* dumps all user functions */
    if (begin_start) {
	fprintf(stdout, "BEGIN\n");
	da(begin_start, stdout);
    }
    if (end_start) {
	fprintf(stdout, "END\n");
	da(end_start, stdout);
    }
    if (main_start) {
	fprintf(stdout, "MAIN\n");
	da(main_start, stdout);
    }
}

static CODEBLOCK *
new_code(void)
{
    CODEBLOCK *p = ZMALLOC(CODEBLOCK);

    p->base = (INST *) zmalloc(INST_BYTES(PAGESZ));
    p->limit = p->base + PAGESZ;
    p->warn = p->limit - CODEWARN;
    p->ptr = p->base;

    return p;
}

/* moves the active_code from MAIN to a BEGIN or END */

void
be_setup(int scope)
{
    *main_code_p = active_code;

    if (scope == SCOPE_BEGIN) {
	if (!begin_code_p)
	    begin_code_p = new_code();
	active_code = *begin_code_p;
    } else {
	if (!end_code_p)
	    end_code_p = new_code();
	active_code = *end_code_p;
    }
}