view lwasm/section.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 35f7ce3ef857
children 8764142b3192
line wrap: on
line source

/*
section.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 <string.h>
#include <ctype.h>

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

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

PARSEFUNC(pseudo_parse_section)
{
	char *p2;
	char *sn;
	char *opts = NULL;
	sectiontab_t *s;

	if (as -> output_format != OUTPUT_OBJ)
	{
		lwasm_register_error(as, l, "Cannot use sections unless using the object target");
		return;
	}
	
	if (!**p)
	{
		lwasm_register_error(as, l, "Need section name");
		return;
	}

	l -> len = 0;

	if (as -> csect)
	{
		lw_expr_destroy(as -> csect -> offset);
		as -> csect -> offset = lw_expr_copy(l -> addr);
		as -> csect = NULL;
	}
	
	for (p2 = *p; *p2 && *p2 != ',' && !isspace(*p2); p2++)
		/* do nothing */ ;
	
	sn = lw_strndup(*p, p2 - *p);
	*p = p2;
	
	if (**p == ',')
	{
		// have opts
		(*p)++;
		
		for (p2 = *p; *p2 && !isspace(*p2); p2++)
			/* do nothing */ ;
		
		opts = lw_strndup(*p, p2 - *p);
		*p = p2;
	}

	for (s = as -> sections; s; s = s -> next)
	{
		if (!strcmp(s -> name, sn))
			break;
	}
	if (s && opts)
	{
		lwasm_register_warning(as, l, "Section flags can only be specified the first time; ignoring duplicate definition");
	}
	if (!s)
	{
		// create section data structure
		s = lw_alloc(sizeof(sectiontab_t));
		s -> oblen = 0;
		s -> obsize = 0;
		s -> obytes = NULL;
		s -> name = lw_strdup(sn);
		s -> offset = lw_expr_build(lw_expr_type_special, lwasm_expr_secbase, s);
		s -> flags = section_flag_none;
		s -> reloctab = NULL;
		if (!strcasecmp(sn, "bss") || !strcasecmp(sn, ".bss"))
		{
			s -> flags |= section_flag_bss;
		}
		if (!strcasecmp(sn, "_constant") || !strcasecmp(sn, "_constants"))
		{
			s -> flags |= section_flag_constant;
		}
		
		// parse options
		if (opts)
		{
			// only one option ("bss" or "!bss")
			if (!strcasecmp(opts, "bss"))
			{
				s -> flags |= section_flag_bss;
			}
			else if (!strcasecmp(opts, "!bss"))
			{
				s -> flags &= ~section_flag_bss;
			}
			else if (!strcasecmp(opts, "constant"))
			{
				s -> flags |= section_flag_constant;
			}
			else if (!strcasecmp(opts, "!constant"))
			{
				s -> flags |= section_flag_constant;
			}
			else
			{
				lwasm_register_error(as, l, "Unrecognized section flag");
				lw_free(sn);
				lw_free(opts);
				lw_free(s -> name);
				lw_expr_destroy(s -> offset);
				lw_free(s);
				return;
			}
		}
		s -> next = as -> sections;
		as -> sections = s;
	}
	
	// cause all instances of "constant" sections to start at 0
	if (s -> flags & section_flag_constant)
		s -> offset = lw_expr_build(lw_expr_type_int, 0);
	lw_expr_destroy(l -> addr);
	l -> addr = lw_expr_copy(s -> offset);
	lw_expr_destroy(l -> daddr);
	l -> daddr = lw_expr_copy(s -> offset);
	as -> csect = s;
	as -> context = lwasm_next_context(as);

	l -> len = 0;
	
	lw_free(opts);
	lw_free(sn);
}

PARSEFUNC(pseudo_parse_endsection)
{
	if (as -> output_format != OUTPUT_OBJ)
	{
		lwasm_register_error(as, l, "Cannot use sections unless using the object target");
		return;
	}

	l -> len = 0;

	if (!(as -> csect))
	{
		lwasm_register_error(as, l, "ENDSECTION without SECTION");
		return;
	}

	// save offset in case another instance of the section appears	
	lw_expr_destroy(as -> csect -> offset);
	as -> csect -> offset = l -> addr;
	
	// reset address to 0
	l -> addr = lw_expr_build(lw_expr_type_int, 0);
	as -> csect = NULL;
	
	// end of section is a context break
	as -> context = lwasm_next_context(as);

	skip_operand(p);
}

PARSEFUNC(pseudo_parse_export)
{
	int after = 0;
	char *sym = NULL;
	exportlist_t *e;
	
	if (as -> output_format != OUTPUT_OBJ)
	{
		lwasm_register_error(as, l, "EXPORT only supported for object target");
		return;
	}

	l -> len = 0;
	
	if (l -> sym)
	{
		sym = lw_strdup(l -> sym);
		l -> symset = 1;
	}
	
	if (l -> sym)
	{
		skip_operand(p);
	}

again:
	if (after || !sym)
	{
		char *p2;
		
		after = 1;
		for (p2 = *p; *p2 && *p2 != ',' && !isspace(*p2); p2++)
			/* do nothing */ ;
		
		sym = lw_strndup(*p, p2 - *p);
		*p = p2;
	}
	if (!sym)
	{
		lwasm_register_error(as, l, "No symbol for EXPORT");
		return;
	}
	
	// add the symbol to the "export" list (which will be resolved
	// after the parse pass is complete
	e = lw_alloc(sizeof(exportlist_t));
	e -> next = as -> exportlist;
	e -> symbol = lw_strdup(sym);
	e -> line = l;
	e -> se = NULL;
	as -> exportlist = e;
	lw_free(sym);
	
	if (after && **p == ',')
	{
		(*p)++;
		for (; **p && isspace(**p); (*p)++)
			/* do nothing */ ;
		goto again;
	}
}

PARSEFUNC(pseudo_parse_extern)
{
	int after = 0;
	char *sym = NULL;
	importlist_t *e;
	
	if (as -> output_format != OUTPUT_OBJ)
	{
		lwasm_register_error(as, l, "IMPORT only supported for object target");
		return;
	}
	
	l -> len = 0;
	
	if (l -> sym)
	{
		sym = lw_strdup(l -> sym);
		l -> symset = 1;
	}
	
	if (l -> sym)
	{
		skip_operand(p);
	}

again:
	if (after || !sym)
	{
		char *p2;
		
		after = 1;
		for (p2 = *p; *p2 && *p2 != ',' && !isspace(*p2); p2++)
			/* do nothing */ ;
		
		sym = lw_strndup(*p, p2 - *p);
		*p = p2;
	}
	if (!sym)
	{
		lwasm_register_error(as, l, "No symbol for IMPORT");
		return;
	}
	
	// add the symbol to the "export" list (which will be resolved
	// after the parse pass is complete
	e = lw_alloc(sizeof(importlist_t));
	e -> next = as -> importlist;
	e -> symbol = lw_strdup(sym);
	as -> importlist = e;
	lw_free(sym);
	
	if (after && **p == ',')
	{
		(*p)++;
		for (; **p && isspace(**p); (*p)++)
			/* do nothing */ ;
		goto again;
	}
}

PARSEFUNC(pseudo_parse_extdep)
{
	int after = 0;
	char *sym = NULL;
//	importlist_t *e;
	
	if (as -> output_format != OUTPUT_OBJ)
	{
		lwasm_register_error(as, l, "EXTDEP only supported for object target");
		return;
	}
	
	if (!as -> csect)
	{
		lwasm_register_error(as, l, "EXTDEP must be within a section");
		return;
	}
	
	l -> len = 0;
	
	if (l -> sym)
		sym = lw_strdup(l -> sym);
	
	if (l -> sym)
	{
		skip_operand(p);
	}

again:
	if (after || !sym)
	{
		char *p2;
		
		after = 1;
		for (p2 = *p; *p2 && *p2 != ',' && !isspace(*p2); p2++)
			/* do nothing */ ;
		
		sym = lw_strndup(*p, p2 - *p);
	}
	if (!sym)
	{
		lwasm_register_error(as, l, "No symbol for EXTDEP");
		return;
	}
	
	// create a zero-width dependency
	{
		lw_expr_t e;
		e = lw_expr_build(lw_expr_type_int, 0);
		lwasm_emitexpr(l, e, 0);
		lw_expr_destroy(e);
	}
	
	if (after && **p == ',')
	{
		(*p)++;
		for (; **p && isspace(**p); (*p)++)
			/* do nothing */ ;
		goto again;
	}
}