view lwasm/macro.c @ 273:1409debcb1a0

Fix crash on listing when nested noexpand macros are used Macros flagged noexpand were causing a segfault during listing. The problem was incorrect accounting for nesting levels for noexpand macros causing the listing handler to fall off the end of the program in certain circumstances and in other circumstances it would fail to suppress expansion. Both the segfault in the case of misbehaviour and the misbhaviour itself are corrected with this update. If you do not use nested noexpand macros, this bug has no effect.
author William Astle <lost@l-w.ca>
date Sat, 25 May 2013 13:35:46 -0600
parents 03f7192fcd20
children 8764142b3192
line wrap: on
line source

/*
macro.c
Copyright © 2008 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 macro processing
*/

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

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

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

PARSEFUNC(pseudo_parse_macro)
{
	macrotab_t *m;
	char *t;
	char tc;
		
	l -> len = 0;
	l -> hideline = 1;
	if (as -> skipcond)
	{
		as -> skipmacro = 1;
		return;
	}
	
	if (as -> inmacro)
	{
		lwasm_register_error(as, l, "Attempt to define a macro inside a macro");
		return;
	}
	
	if (!(l -> sym))
	{
		lwasm_register_error(as, l, "Missing macro name");
		return;
	}

	for (m = as -> macros; m; m = m -> next)
	{
		if (!strcmp(m -> name, l -> sym))
			break;
	}
	if (m)
	{
		lwasm_register_error(as, l, "Duplicate macro definition");
		return;
	}
	
	m = lw_alloc(sizeof(macrotab_t));
	m -> name = lw_strdup(l -> sym);
	m -> next = as -> macros;
	m -> lines = NULL;
	m -> numlines = 0;
	m -> flags = 0;
	m -> definedat = l;
	as -> macros = m;

	t = *p;
	while (**p && !isspace(**p))
		(*p)++;
	tc = **p;
	/* ignore unknown flags */
	if (strcasecmp(t, "noexpand") == 0)
		m -> flags |= macro_noexpand;
	**p = tc;
	as -> inmacro = 1;
}

PARSEFUNC(pseudo_parse_endm)
{
	l -> hideline = 1;
	l -> len = 0;

	if (as -> skipcond)
	{
		as -> skipmacro = 0;
		return;
	}
	
	if (!as -> inmacro)
	{
		lwasm_register_error(as, l, "ENDM without MACRO");
		return;
	}
	
	as -> inmacro = 0;
	
	// a macro definition counts as a context break for local symbols
	as -> context = lwasm_next_context(as);
}

// the current macro will ALWAYS be the first one in the table
int add_macro_line(asmstate_t *as, char *optr)
{
	if (!as -> inmacro)
		return 0;
	
	as -> macros -> lines = lw_realloc(as -> macros -> lines, sizeof(char *) * (as -> macros -> numlines + 1));
	as -> macros -> lines[as -> macros -> numlines] = lw_strdup(optr);
	as -> macros -> numlines += 1;
	return 1;
}

void macro_add_to_buff(char **buff, int *loc, int *len, char c)
{
	if (*loc == *len)
	{
		*buff = lw_realloc(*buff, *len + 32);
		*len += 32;
	}
	(*buff)[(*loc)++] = c;
}

// this is just like a regular operation function
/*
macro args are referenced by "\n" where 1 <= n <= 9
or by "\{n}"; a \ can be included by writing \\
a comma separates argument but one can be included with "\,"
whitespace ends argument list but can be included with "\ " or the like

*/
int expand_macro(asmstate_t *as, line_t *l, char **p, char *opc)
{
	int lc;
	line_t *cl; //, *nl;
	int oldcontext;
	macrotab_t *m;

	char **args = NULL;		// macro arguments
	int nargs = 0;			// number of arguments

	char *p2, *p3;
	
	int bloc, blen;
	char *linebuff;

	for (m = as -> macros; m; m = m -> next)
	{
		if (!strcmp(opc, m -> name))
			break;
	}
	// signal no macro expansion
	if (!m)
		return -1;
	
	// save current symbol context for after macro expansion
	oldcontext = as -> context;

	cl = l;

	as -> context = lwasm_next_context(as);

	while (**p && !isspace(**p) && **p)
	{
		p2 = *p;
		while (*p2 && !isspace(*p2) && *p2 != ',')
		{
			if (*p2 == '\\')
			{
				if (p2[1])
					p2++;
			}
			p2++;
		}

		// have arg here
		args = lw_realloc(args, sizeof(char *) * (nargs + 1));
		args[nargs] = lw_alloc(p2 - *p + 1);
		args[nargs][p2 - *p] = '\0';
		memcpy(args[nargs], *p, p2 - *p);
		*p = p2;

		// now collapse out "\" characters
		for (p3 = p2 = args[nargs]; *p2; p2++, p3++)
		{
			if (*p2 == '\\' && p2[1])
			{
				p2++;
			}
			*p3 = *p2;
		}
		*p3 = '\0';
		
		nargs++;
		if (**p == ',')
			(*p)++;
	}
	

	// now create a string for the macro
	// and push it into the front of the input stack
	bloc = blen = 0;
	linebuff = NULL;

	if (m -> flags & macro_noexpand)
	{
		char ctcbuf[100];
		char *p;
		snprintf(ctcbuf, 100, "\001\001SETNOEXPANDSTART\n");
		for (p = ctcbuf; *p; p++)
			macro_add_to_buff(&linebuff, &bloc, &blen, *p);
	}

	
	for (lc = 0; lc < m -> numlines; lc++)
	{
		for (p2 = m -> lines[lc]; *p2; p2++)
		{
			if (*p2 == '\\' && p2[1] == '*')
			{
				int n;
				/* all arguments */
				for (n = 0; n < nargs; n++)
				{
					for (p3 = args[n]; *p3; p3++)
					{
						macro_add_to_buff(&linebuff, &bloc, &blen, *p3);
					}
					if (n != (nargs -1))
					{
						macro_add_to_buff(&linebuff, &bloc, &blen, ',');
					}
				}
				p2++;
			}
			else if (*p2 == '\\' && isdigit(p2[1]))
			{
				int n;
					
				p2++;
				n = *p2 - '0';
				if (n == 0)
				{
					for (p3 = m -> name; *p3; p3++)
						macro_add_to_buff(&linebuff, &bloc, &blen, *p3);
					continue;
				}
				if (n < 1 || n > nargs)
					continue;
				for (p3 = args[n - 1]; *p3; p3++)
					macro_add_to_buff(&linebuff, &bloc, &blen, *p3);
				continue;
			}
			else if (*p2 == '{')
			{
				int n = 0, n2;
				p2++;
				while (*p2 && isdigit(*p2))
				{
					n2 = *p2 - '0';
					if (n2 < 0 || n2 > 9)
						n2 = 0;
					n = n * 10 + n2;
					p2++;
				}
				if (*p2 == '}')
					p2++;
				 
				if (n == 0)
				{
					for (p3 = m -> name; *p3; p3++)
						macro_add_to_buff(&linebuff, &bloc, &blen, *p3);
					continue;
				}
				if (n < 1 || n > nargs)
					continue;
				for (p3 = args[n - 1]; *p3; p3++)
					macro_add_to_buff(&linebuff, &bloc, &blen, *p3);
				continue;
			}
			else
			{
				macro_add_to_buff(&linebuff, &bloc, &blen, *p2);
			}
		}

		macro_add_to_buff(&linebuff, &bloc, &blen, '\n');
		
	}

	if (m -> flags & macro_noexpand)
	{
		char ctcbuf[100];
		char *p;
		snprintf(ctcbuf, 100, "\001\001SETNOEXPANDEND\n");
		for (p = ctcbuf; *p; p++)
			macro_add_to_buff(&linebuff, &bloc, &blen, *p);
	}

	{
		char ctcbuf[100];
		char *p;
		snprintf(ctcbuf, 100, "\001\001SETCONTEXT %d\n\001\001SETLINENO %d\n", oldcontext, cl -> lineno + 1);
		for (p = ctcbuf; *p; p++)
			macro_add_to_buff(&linebuff, &bloc, &blen, *p);
	}
	macro_add_to_buff(&linebuff, &bloc, &blen, 0);
	
	// push the macro into the front of the stream
	input_openstring(as, opc, linebuff);
	lw_free(linebuff);

	// clean up
	if (args)
	{
		while (nargs)
		{
			lw_free(args[--nargs]);
		}
		lw_free(args);
	}

	// indicate a macro was expanded
	l -> hideline = 1;
	return 0;	
}