view lwasm/pass4.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

/*
pass4.c

Copyright © 2010 William Astle

This file is part of LWTOOLS.

LWTOOLS 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/>.
*/

#include <stdio.h>
#include <string.h>

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

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

/*
Resolve2 Pass

Force resolution of instruction sizes.

*/
void do_pass4_aux(asmstate_t *as, int force)
{
	int rc;
	int cnt;
	line_t *cl, *sl;
	struct line_expr_s *le;
	int trycount = 0;

	// first, count the number of unresolved instructions
	for (cnt = 0, cl = as -> line_head; cl; cl = cl -> next)
	{
		if (cl -> len == -1)
			cnt++;
	}

	sl = as -> line_head;
	while (cnt > 0)
	{
		trycount = cnt;
		debug_message(as, 60, "%d unresolved instructions", cnt);

		// find an unresolved instruction
		for ( ; sl && sl -> len != -1; sl = sl -> next)
		{
			debug_message(as, 200, "Search line %p", sl);
			as -> cl = sl;
			lwasm_reduce_expr(as, sl -> addr);
			lwasm_reduce_expr(as, sl -> daddr);
	
			// simplify each expression
			for (le = sl -> exprs; le; le = le -> next)
				lwasm_reduce_expr(as, le -> expr);
		}
		
		debug_message(as, 200, "Found line %p", sl);
		// simplify address
		as -> cl = sl;
		lwasm_reduce_expr(as, sl -> addr);
		lwasm_reduce_expr(as, sl -> daddr);
			
		// simplify each expression
		for (le = sl -> exprs; le; le = le -> next)
			lwasm_reduce_expr(as, le -> expr);


		if (sl -> len == -1 && sl -> insn >= 0 && instab[sl -> insn].resolve)
		{
			(instab[sl -> insn].resolve)(as, sl, 1);
			debug_message(as, 200, "Try resolve = %d/%d", sl -> len, sl -> dlen);
			if (force && sl -> len == -1 && sl -> dlen == -1)
			{
				lwasm_register_error(as, sl, E_INSTRUCTION_FAILED);
				return;
			}
		}
		if (sl -> len != -1 && sl -> dlen != -1)
		{
			cnt--;
			if (cnt == 0)
				return;
			
			// this one resolved - try looking for the next one instead
			// of wasting time running through the rest of the lines
			continue;
		}

		do
		{
			debug_message(as, 200, "Flatten after...");
			rc = 0;
			for (cl = sl; cl; cl = cl -> next)
			{
				debug_message(as, 200, "Flatten line %p", cl);
				as -> cl = cl;
			
				// simplify address
				lwasm_reduce_expr(as, cl -> addr);
				lwasm_reduce_expr(as, cl -> daddr);
				// simplify each expression
				for (le = cl -> exprs; le; le = le -> next)
					lwasm_reduce_expr(as, le -> expr);
			
				if (cl -> len == -1)
				{
					// try resolving the instruction length
					// but don't force resolution
					if (cl -> insn >= 0 && instab[cl -> insn].resolve)
					{
						(instab[cl -> insn].resolve)(as, cl, 0);
						if ((cl -> inmod == 0) && cl -> len >= 0 && cl -> dlen >= 0)
						{
							if (cl -> len == 0)
								cl -> len = cl -> dlen;
							else
								cl -> dlen = cl -> len;
						}
						debug_message(as, 200, "Flatten resolve returns %d", cl -> len);
						if (cl -> len != -1 && cl -> dlen != -1)
						{
							rc++;
							cnt--;
							if (cnt == 0)
								return;
						}
					}
				}
			}
			if (as -> errorcount > 0)
				return;
		} while (rc > 0);
		if (trycount == cnt)
			break;
	}
}

void do_pass4(asmstate_t *as)
{
	do_pass4_aux(as, 1);
}