view lwasm/struct.c @ 393:f2decd9b276d

Fix minor error in string parsing Growing a buffer by 32 bytes and then only saying the buffer grew by one byte is not exactly efficient. While not strictly broken, it's dumb. Fix it to actually count the 32 bytes.
author William Astle <lost@l-w.ca>
date Tue, 14 Jul 2015 23:12:24 -0600
parents 8764142b3192
children
line wrap: on
line source

/*
struct.c
Copyright © 2010 William Astle

This file is part of LWASM.

LWASM 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/>.

Contains stuff associated with structure processing
*/

#include <string.h>

#include <lw_alloc.h>
#include <lw_string.h>

#include "lwasm.h"
#include "instab.h"

PARSEFUNC(pseudo_parse_struct)
{
	structtab_t *s;
	
	if (as -> instruct)
	{
		lwasm_register_error(as, l, E_STRUCT_RECURSE);
		return;
	}
	
	if (l -> sym == NULL)
	{
		lwasm_register_error(as, l, E_STRUCT_NOSYMBOL);
		return;
	}
	
	for (s = as -> structs; s; s = s -> next)
	{
		if (!strcmp(s -> name, l -> sym))	
			break;
	}
	
	if (s)
	{
		lwasm_register_error(as, l, E_STRUCT_DUPE);
		return;
	}
	
	as -> instruct = 1;
	
	s = lw_alloc(sizeof(structtab_t));
	s -> name = lw_strdup(l -> sym);
	s -> next = as -> structs;
	s -> fields = NULL;
	s -> size = 0;
	s -> definedat = l;
	as -> structs = s;
	as -> cstruct = s;
	
	skip_operand(p);
	
	l -> len = 0;
	l -> symset = 1;
	
	// save current assembly address and initialize to 0
	as -> savedaddr = l -> addr;
	l -> addr = lw_expr_build(lw_expr_type_int, 0);
}

static void instantiate_struct(asmstate_t *as, line_t *l, structtab_t *s, char *pref, lw_expr_t baseaddr)
{
	int len;
	char *t;
	int plen;
	int addr = 0;
	lw_expr_t te, te2;
	structtab_field_t *e;

	if (baseaddr == NULL)
		baseaddr = l -> addr;
	
	plen = strlen(pref);
	for (e = s -> fields; e; e = e -> next)
	{
		if (e -> name)
		{
			len = plen + strlen(e -> name) + 1;
			t = lw_alloc(len + 1);
			sprintf(t, "%s.%s", pref, e -> name);
		}
		else
		{
			len = plen + 30;
			t = lw_alloc(len + 1);
			sprintf(t, "%s.____%d", pref, addr);
		}

		te = lw_expr_build(lw_expr_type_int, addr);
		te2 = lw_expr_build(lw_expr_type_oper, lw_expr_oper_plus, te, baseaddr);
		register_symbol(as, l, t, te2, symbol_flag_nocheck);
		lw_expr_destroy(te);
		
		if (e -> substruct)
		{
			instantiate_struct(as, l, e -> substruct, t, te2);
		}
		
		lw_expr_destroy(te2);
		
		lw_free(t);
		addr += e -> size;
	}
	
	/* register the "sizeof" symbol */
	len = plen + 8;
	t = lw_alloc(len + 1);
	sprintf(t, "sizeof{%s}", pref);
	te = lw_expr_build(lw_expr_type_int, s -> size);
	register_symbol(as, l, t, te, symbol_flag_nocheck);
	lw_expr_destroy(te);
	lw_free(t);
}


PARSEFUNC(pseudo_parse_endstruct)
{
	lw_expr_t te;
		
	if (as -> instruct == 0)
	{
		lwasm_register_error(as, l, W_ENDSTRUCT_WITHOUT);
		skip_operand(p);
		return;
	}

	te = lw_expr_build(lw_expr_type_int, 0);
	
	// make all the relevant generic struct symbols
	instantiate_struct(as, l, as -> cstruct, as -> cstruct -> name, te);
	lw_expr_destroy(te);
	
	l -> soff = as -> cstruct -> size;
	as -> instruct = 0;
	
	skip_operand(p);
	
	lw_expr_destroy(l -> addr);
	l -> addr = as -> savedaddr;
	as -> savedaddr = NULL;
	
	l -> len = 0;
}

void register_struct_entry(asmstate_t *as, line_t *l, int size, structtab_t *ss)
{
	structtab_field_t *e, *e2;
	
	l -> soff = as -> cstruct -> size;
	e = lw_alloc(sizeof(structtab_field_t));
	e -> next = NULL;
	e -> size = size;
	if (l -> sym)
		e -> name = lw_strdup(l -> sym);
	else
		e -> name = NULL;
	e -> substruct = ss;
	if (as -> cstruct -> fields)
	{
		for (e2 = as -> cstruct -> fields; e2 -> next; e2 = e2 -> next)
			/* do nothing */ ;
		e2 -> next = e;
	}
	else
	{
		as -> cstruct -> fields = e;
	}
	as -> cstruct -> size += size;
}

int expand_struct(asmstate_t *as, line_t *l, char **p, char *opc)
{
	structtab_t *s;
	
	debug_message(as, 200, "Checking for structure expansion: %s", opc);

	for (s = as -> structs; s; s = s -> next)
	{
		if (!strcmp(opc, s -> name))
			break;
	}
	
	if (!s)
		return -1;
	
	debug_message(as, 10, "Expanding structure: %s", opc);
	
	if (!(l -> sym))
	{
		lwasm_register_error(as, l, E_STRUCT_NONAME);
		return -1;
	}

	l -> len = s -> size;

	if (as -> instruct)
	{
		/* register substruct here */
		register_struct_entry(as, l, s -> size, s);
		/* mark the symbol consumed */
		l -> symset = 1;
		l -> len = 0;
		return 0;
	}
	else
	{
		/* instantiate the struct here */
		instantiate_struct(as, l, s, l -> sym, NULL);
		return 0;
	}
	
	return 0;
}