fixup_tdescs.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

/*
 * Workarounds for stabs generation bugs in the compiler and general needed
 * fixups.
 */

#include <stdio.h>
#include <strings.h>

#include "ctf_headers.h"
#include "ctftools.h"
#include "hash.h"
#include "memory.h"

struct match {
	tdesc_t *m_ret;
	const char *m_name;
};

static int
matching_iidesc(void *arg1, void *arg2)
{
	iidesc_t *iidesc = arg1;
	struct match *match = arg2;
	if (!streq(iidesc->ii_name, match->m_name))
		return (0);

	if (iidesc->ii_type != II_TYPE && iidesc->ii_type != II_SOU)
		return (0);

	match->m_ret = iidesc->ii_dtype;
	return (-1);
}

static tdesc_t *
lookup_tdesc(tdata_t *td, char const *name)
{
	struct match match = { NULL, name };
	iter_iidescs_by_name(td, name, matching_iidesc, &match);
	return (match.m_ret);
}

/*
 * The cpu structure grows, with the addition of a machcpu member, if
 * _MACHDEP is defined.  This means that, for example, the cpu structure
 * in unix is different from the cpu structure in genunix.  As one might
 * expect, this causes merges to fail.  Since everyone indirectly contains
 * a pointer to a CPU structure, the failed merges can cause massive amounts
 * of duplication.  In the case of unix uniquifying against genunix, upwards
 * of 50% of the structures were unmerged due to this problem.  We fix this
 * by adding a cpu_m member.  If machcpu hasn't been defined in our module,
 * we make a forward node for it.
 */
static void
fix_small_cpu_struct(tdata_t *td, size_t ptrsize)
{
	tdesc_t *cput, *cpu;
	tdesc_t *machcpu;
	mlist_t *ml, *lml;
	mlist_t *cpum;
	int foundcpucyc = 0;

	/*
	 * We're going to take the circuitous route finding the cpu structure,
	 * because we want to make sure that we find the right one.  It would
	 * be nice if we could verify the header name too.  DWARF might not
	 * have the cpu_t, so we let this pass.
	 */
	if ((cput = lookup_tdesc(td, "cpu_t")) != NULL) {
		if (cput->t_type != TYPEDEF)
			return;
		cpu = cput->t_tdesc;
	} else {
		cpu = lookup_tdesc(td, "cpu");
	}

	if (cpu == NULL)
		return;

	if (!streq(cpu->t_name, "cpu") || cpu->t_type != STRUCT)
		return;

	for (ml = cpu->t_members, lml = NULL; ml;
	    lml = ml, ml = ml->ml_next) {
		if (strcmp(ml->ml_name, "cpu_cyclic") == 0)
			foundcpucyc = 1;
	}

	if (foundcpucyc == 0 || lml == NULL ||
	    strcmp(lml->ml_name, "cpu_m") == 0)
		return;

	/*
	 * We need to derive the right offset for the fake cpu_m member.  To do
	 * that, we require a special unused member to be the last member
	 * before the 'cpu_m', that we encode knowledge of here.  ABI alignment
	 * on all platforms is such that we only need to add a pointer-size
	 * number of bits to get the right offset for cpu_m.  This would most
	 * likely break if gcc's -malign-double were ever used, but that option
	 * breaks the ABI anyway.
	 */
	if (!streq(lml->ml_name, "cpu_m_pad") &&
	    getenv("CTFCONVERT_PERMISSIVE") == NULL) {
		terminate("last cpu_t member before cpu_m is %s; "
		    "it must be cpu_m_pad.\n", lml->ml_name);
	}

	if ((machcpu = lookup_tdesc(td, "machcpu")) == NULL) {
		machcpu = xcalloc(sizeof (*machcpu));
		machcpu->t_name = xstrdup("machcpu");
		machcpu->t_id = td->td_nextid++;
		machcpu->t_type = FORWARD;
	} else if (machcpu->t_type != STRUCT) {
		return;
	}

	debug(3, "Adding cpu_m machcpu %s to cpu struct\n",
	    (machcpu->t_type == FORWARD ? "forward" : "struct"));

	cpum = xmalloc(sizeof (*cpum));
	cpum->ml_offset = lml->ml_offset + (ptrsize * NBBY);
	cpum->ml_size = 0;
	cpum->ml_name = xstrdup("cpu_m");
	cpum->ml_type = machcpu;
	cpum->ml_next = NULL;

	lml->ml_next = cpum;
}

void
cvt_fixups(tdata_t *td, size_t ptrsize)
{
	fix_small_cpu_struct(td, ptrsize);
}