MFC r260880 (by kaiw, from projects/elftoolchain):

[FreeBSD/stable/9.git] / cddl / contrib / opensolaris / tools / ctf / cvt / dwarf.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 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * DWARF to tdata conversion
 *
 * For the most part, conversion is straightforward, proceeding in two passes.
 * On the first pass, we iterate through every die, creating new type nodes as
 * necessary.  Referenced tdesc_t's are created in an uninitialized state, thus
 * allowing type reference pointers to be filled in.  If the tdesc_t
 * corresponding to a given die can be completely filled out (sizes and offsets
 * calculated, and so forth) without using any referenced types, the tdesc_t is
 * marked as resolved.  Consider an array type.  If the type corresponding to
 * the array contents has not yet been processed, we will create a blank tdesc
 * for the contents type (only the type ID will be filled in, relying upon the
 * later portion of the first pass to encounter and complete the referenced
 * type).  We will then attempt to determine the size of the array.  If the
 * array has a byte size attribute, we will have completely characterized the
 * array type, and will be able to mark it as resolved.  The lack of a byte
 * size attribute, on the other hand, will prevent us from fully resolving the
 * type, as the size will only be calculable with reference to the contents
 * type, which has not, as yet, been encountered.  The array type will thus be
 * left without the resolved flag, and the first pass will continue.
 *
 * When we begin the second pass, we will have created tdesc_t nodes for every
 * type in the section.  We will traverse the tree, from the iidescs down,
 * processing each unresolved node.  As the referenced nodes will have been
 * populated, the array type used in our example above will be able to use the
 * size of the referenced types (if available) to determine its own type.  The
 * traversal will be repeated until all types have been resolved or we have
 * failed to make progress.  When all tdescs have been resolved, the conversion
 * is complete.
 *
 * There are, as always, a few special cases that are handled during the first
 * and second passes:
 *
 *  1. Empty enums - GCC will occasionally emit an enum without any members.
 *     Later on in the file, it will emit the same enum type, though this time
 *     with the full complement of members.  All references to the memberless
 *     enum need to be redirected to the full definition.  During the first
 *     pass, each enum is entered in dm_enumhash, along with a pointer to its
 *     corresponding tdesc_t.  If, during the second pass, we encounter a
 *     memberless enum, we use the hash to locate the full definition.  All
 *     tdescs referencing the empty enum are then redirected.
 *
 *  2. Forward declarations - If the compiler sees a forward declaration for
 *     a structure, followed by the definition of that structure, it will emit
 *     DWARF data for both the forward declaration and the definition.  We need
 *     to resolve the forward declarations when possible, by redirecting
 *     forward-referencing tdescs to the actual struct/union definitions.  This
 *     redirection is done completely within the first pass.  We begin by
 *     recording all forward declarations in dw_fwdhash.  When we define a
 *     structure, we check to see if there have been any corresponding forward
 *     declarations.  If so, we redirect the tdescs which referenced the forward
 *     declarations to the structure or union definition.
 *
 * XXX see if a post traverser will allow the elimination of repeated pass 2
 * traversals.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <errno.h>
#include <libelf.h>
#include <libdwarf.h>
#include <libgen.h>
#include <dwarf.h>

#include "ctf_headers.h"
#include "ctftools.h"
#include "memory.h"
#include "list.h"
#include "traverse.h"

/* The version of DWARF which we support. */
#define DWARF_VERSION   2

/*
 * We need to define a couple of our own intrinsics, to smooth out some of the
 * differences between the GCC and DevPro DWARF emitters.  See the referenced
 * routines and the special cases in the file comment for more details.
 *
 * Type IDs are 32 bits wide.  We're going to use the top of that field to
 * indicate types that we've created ourselves.
 */
#define TID_FILEMAX             0x3fffffff      /* highest tid from file */
#define TID_VOID                0x40000001      /* see die_void() */
#define TID_LONG                0x40000002      /* see die_array() */

#define TID_MFGTID_BASE         0x40000003      /* first mfg'd tid */

/*
 * To reduce the staggering amount of error-handling code that would otherwise
 * be required, the attribute-retrieval routines handle most of their own
 * errors.  If the following flag is supplied as the value of the `req'
 * argument, they will also handle the absence of a requested attribute by
 * terminating the program.
 */
#define DW_ATTR_REQ     1

#define TDESC_HASH_BUCKETS      511

typedef struct dwarf {
        Dwarf_Debug dw_dw;              /* for libdwarf */
        Dwarf_Error dw_err;             /* for libdwarf */
        Dwarf_Off dw_maxoff;            /* highest legal offset in this cu */
        tdata_t *dw_td;                 /* root of the tdesc/iidesc tree */
        hash_t *dw_tidhash;             /* hash of tdescs by t_id */
        hash_t *dw_fwdhash;             /* hash of fwd decls by name */
        hash_t *dw_enumhash;            /* hash of memberless enums by name */
        tdesc_t *dw_void;               /* manufactured void type */
        tdesc_t *dw_long;               /* manufactured long type for arrays */
        size_t dw_ptrsz;                /* size of a pointer in this file */
        tid_t dw_mfgtid_last;           /* last mfg'd type ID used */
        uint_t dw_nunres;               /* count of unresolved types */
        char *dw_cuname;                /* name of compilation unit */
} dwarf_t;

static void die_create_one(dwarf_t *, Dwarf_Die);
static void die_create(dwarf_t *, Dwarf_Die);

static tid_t
mfgtid_next(dwarf_t *dw)
{
        return (++dw->dw_mfgtid_last);
}

static void
tdesc_add(dwarf_t *dw, tdesc_t *tdp)
{
        hash_add(dw->dw_tidhash, tdp);
}

static tdesc_t *
tdesc_lookup(dwarf_t *dw, int tid)
{
        tdesc_t tmpl;
        void *tdp;

        tmpl.t_id = tid;

        if (hash_find(dw->dw_tidhash, &tmpl, &tdp))
                return (tdp);
        else
                return (NULL);
}

/*
 * Resolve a tdesc down to a node which should have a size.  Returns the size,
 * zero if the size hasn't yet been determined.
 */
static size_t
tdesc_size(tdesc_t *tdp)
{
        for (;;) {
                switch (tdp->t_type) {
                case INTRINSIC:
                case POINTER:
                case ARRAY:
                case FUNCTION:
                case STRUCT:
                case UNION:
                case ENUM:
                        return (tdp->t_size);

                case FORWARD:
                        return (0);

                case TYPEDEF:
                case VOLATILE:
                case CONST:
                case RESTRICT:
                        tdp = tdp->t_tdesc;
                        continue;

                case 0: /* not yet defined */
                        return (0);

                default:
                        terminate("tdp %u: tdesc_size on unknown type %d\n",
                            tdp->t_id, tdp->t_type);
                }
        }
}

static size_t
tdesc_bitsize(tdesc_t *tdp)
{
        for (;;) {
                switch (tdp->t_type) {
                case INTRINSIC:
                        return (tdp->t_intr->intr_nbits);

                case ARRAY:
                case FUNCTION:
                case STRUCT:
                case UNION:
                case ENUM:
                case POINTER:
                        return (tdp->t_size * NBBY);

                case FORWARD:
                        return (0);

                case TYPEDEF:
                case VOLATILE:
                case RESTRICT:
                case CONST:
                        tdp = tdp->t_tdesc;
                        continue;

                case 0: /* not yet defined */
                        return (0);

                default:
                        terminate("tdp %u: tdesc_bitsize on unknown type %d\n",
                            tdp->t_id, tdp->t_type);
                }
        }
}

static tdesc_t *
tdesc_basetype(tdesc_t *tdp)
{
        for (;;) {
                switch (tdp->t_type) {
                case TYPEDEF:
                case VOLATILE:
                case RESTRICT:
                case CONST:
                        tdp = tdp->t_tdesc;
                        break;
                case 0: /* not yet defined */
                        return (NULL);
                default:
                        return (tdp);
                }
        }
}

static Dwarf_Off
die_off(dwarf_t *dw, Dwarf_Die die)
{
        Dwarf_Off off;

        if (dwarf_dieoffset(die, &off, &dw->dw_err) == DW_DLV_OK)
                return (off);

        terminate("failed to get offset for die: %s\n",
            dwarf_errmsg(&dw->dw_err));
        /*NOTREACHED*/
        return (0);
}

static Dwarf_Die
die_sibling(dwarf_t *dw, Dwarf_Die die)
{
        Dwarf_Die sib;
        int rc;

        if ((rc = dwarf_siblingof(dw->dw_dw, die, &sib, &dw->dw_err)) ==
            DW_DLV_OK)
                return (sib);
        else if (rc == DW_DLV_NO_ENTRY)
                return (NULL);

        terminate("die %llu: failed to find type sibling: %s\n",
            die_off(dw, die), dwarf_errmsg(&dw->dw_err));
        /*NOTREACHED*/
        return (NULL);
}

static Dwarf_Die
die_child(dwarf_t *dw, Dwarf_Die die)
{
        Dwarf_Die child;
        int rc;

        if ((rc = dwarf_child(die, &child, &dw->dw_err)) == DW_DLV_OK)
                return (child);
        else if (rc == DW_DLV_NO_ENTRY)
                return (NULL);

        terminate("die %llu: failed to find type child: %s\n",
            die_off(dw, die), dwarf_errmsg(&dw->dw_err));
        /*NOTREACHED*/
        return (NULL);
}

static Dwarf_Half
die_tag(dwarf_t *dw, Dwarf_Die die)
{
        Dwarf_Half tag;

        if (dwarf_tag(die, &tag, &dw->dw_err) == DW_DLV_OK)
                return (tag);

        terminate("die %llu: failed to get tag for type: %s\n",
            die_off(dw, die), dwarf_errmsg(&dw->dw_err));
        /*NOTREACHED*/
        return (0);
}

static Dwarf_Attribute
die_attr(dwarf_t *dw, Dwarf_Die die, Dwarf_Half name, int req)
{
        Dwarf_Attribute attr;
        int rc;

        if ((rc = dwarf_attr(die, name, &attr, &dw->dw_err)) == DW_DLV_OK) {
                return (attr);
        } else if (rc == DW_DLV_NO_ENTRY) {
                if (req) {
                        terminate("die %llu: no attr 0x%x\n", die_off(dw, die),
                            name);
                } else {
                        return (NULL);
                }
        }

        terminate("die %llu: failed to get attribute for type: %s\n",
            die_off(dw, die), dwarf_errmsg(&dw->dw_err));
        /*NOTREACHED*/
        return (NULL);
}

static int
die_signed(dwarf_t *dw, Dwarf_Die die, Dwarf_Half name, Dwarf_Signed *valp,
    int req)
{
        *valp = 0;
        if (dwarf_attrval_signed(die, name, valp, &dw->dw_err) != DWARF_E_NONE) {
                if (req) 
                        terminate("die %llu: failed to get signed: %s\n",
                            die_off(dw, die), dwarf_errmsg(&dw->dw_err));
                return (0);
        }

        return (1);
}

static int
die_unsigned(dwarf_t *dw, Dwarf_Die die, Dwarf_Half name, Dwarf_Unsigned *valp,
    int req)
{
        *valp = 0;
        if (dwarf_attrval_unsigned(die, name, valp, &dw->dw_err) != DWARF_E_NONE) {
                if (req) 
                        terminate("die %llu: failed to get unsigned: %s\n",
                            die_off(dw, die), dwarf_errmsg(&dw->dw_err));
                return (0);
        }

        return (1);
}

static int
die_bool(dwarf_t *dw, Dwarf_Die die, Dwarf_Half name, Dwarf_Bool *valp, int req)
{
        *valp = 0;

        if (dwarf_attrval_flag(die, name, valp, &dw->dw_err) != DWARF_E_NONE) {
                if (req) 
                        terminate("die %llu: failed to get flag: %s\n",
                            die_off(dw, die), dwarf_errmsg(&dw->dw_err));
                return (0);
        }

        return (1);
}

static int
die_string(dwarf_t *dw, Dwarf_Die die, Dwarf_Half name, char **strp, int req)
{
        const char *str = NULL;

        if (dwarf_attrval_string(die, name, &str, &dw->dw_err) != DWARF_E_NONE ||
            str == NULL) {
                if (req) 
                        terminate("die %llu: failed to get string: %s\n",
                            die_off(dw, die), dwarf_errmsg(&dw->dw_err));
                else
                        *strp = NULL;
                return (0);
        } else
                *strp = xstrdup(str);

        return (1);
}

static Dwarf_Off
die_attr_ref(dwarf_t *dw, Dwarf_Die die, Dwarf_Half name)
{
        Dwarf_Off off;

        if (dwarf_attrval_unsigned(die, name, &off, &dw->dw_err) != DWARF_E_NONE) {
                terminate("die %llu: failed to get ref: %s\n",
                    die_off(dw, die), dwarf_errmsg(&dw->dw_err));
        }

        return (off);
}

static char *
die_name(dwarf_t *dw, Dwarf_Die die)
{
        char *str = NULL;

        (void) die_string(dw, die, DW_AT_name, &str, 0);

        return (str);
}

static int
die_isdecl(dwarf_t *dw, Dwarf_Die die)
{
        Dwarf_Bool val;

        return (die_bool(dw, die, DW_AT_declaration, &val, 0) && val);
}

static int
die_isglobal(dwarf_t *dw, Dwarf_Die die)
{
        Dwarf_Signed vis;
        Dwarf_Bool ext;

        /*
         * Some compilers (gcc) use DW_AT_external to indicate function
         * visibility.  Others (Sun) use DW_AT_visibility.
         */
        if (die_signed(dw, die, DW_AT_visibility, &vis, 0))
                return (vis == DW_VIS_exported);
        else
                return (die_bool(dw, die, DW_AT_external, &ext, 0) && ext);
}

static tdesc_t *
die_add(dwarf_t *dw, Dwarf_Off off)
{
        tdesc_t *tdp = xcalloc(sizeof (tdesc_t));

        tdp->t_id = off;

        tdesc_add(dw, tdp);

        return (tdp);
}

static tdesc_t *
die_lookup_pass1(dwarf_t *dw, Dwarf_Die die, Dwarf_Half name)
{
        Dwarf_Off ref = die_attr_ref(dw, die, name);
        tdesc_t *tdp;

        if ((tdp = tdesc_lookup(dw, ref)) != NULL)
                return (tdp);

        return (die_add(dw, ref));
}

static int
die_mem_offset(dwarf_t *dw, Dwarf_Die die, Dwarf_Half name,
    Dwarf_Unsigned *valp, int req __unused)
{
        Dwarf_Locdesc *loc = NULL;
        Dwarf_Signed locnum = 0;
        Dwarf_Attribute at;
        Dwarf_Half form;

        if (name != DW_AT_data_member_location)
                terminate("die %llu: can only process attribute "
                    "DW_AT_data_member_location\n", die_off(dw, die));

        if ((at = die_attr(dw, die, name, 0)) == NULL)
                return (0);

        if (dwarf_whatform(at, &form, &dw->dw_err) != DW_DLV_OK)
                return (0);

        switch (form) {
        case DW_FORM_block:
        case DW_FORM_block1:
        case DW_FORM_block2:
        case DW_FORM_block4:
                /*
                 * GCC in base and Clang (3.3 or below) generates
                 * DW_AT_data_member_location attribute with DW_FORM_block*
                 * form. The attribute contains one DW_OP_plus_uconst
                 * operator. The member offset stores in the operand.
                 */
                if (dwarf_locdesc(die, name, &loc, &locnum, &dw->dw_err) !=
                    DW_DLV_OK)
                        return (0);
                if (locnum != 1 || loc->ld_s->lr_atom != DW_OP_plus_uconst) {
                        terminate("die %llu: cannot parse member offset\n",
                            die_off(dw, die));
                }
                *valp = loc->ld_s->lr_number;
                break;

        case DW_FORM_data1:
        case DW_FORM_data2:
        case DW_FORM_data4:
        case DW_FORM_data8:
        case DW_FORM_udata:
                /*
                 * Clang 3.4 generates DW_AT_data_member_location attribute
                 * with DW_FORM_data* form (constant class). The attribute
                 * stores a contant value which is the member offset.
                 */
                if (dwarf_attrval_unsigned(die, name, valp, &dw->dw_err) !=
                    DW_DLV_OK)
                        return (0);
                break;

        default:
                terminate("die %llu: cannot parse member offset with form "
                    "%u\n", die_off(dw, die), form);
        }

        if (loc != NULL)
                if (dwarf_locdesc_free(loc, &dw->dw_err) != DW_DLV_OK)
                        terminate("die %llu: cannot free location descriptor: %s\n",
                            die_off(dw, die), dwarf_errmsg(&dw->dw_err));

        return (1);
}

static tdesc_t *
tdesc_intr_common(dwarf_t *dw, int tid, const char *name, size_t sz)
{
        tdesc_t *tdp;
        intr_t *intr;

        intr = xcalloc(sizeof (intr_t));
        intr->intr_type = INTR_INT;
        intr->intr_signed = 1;
        intr->intr_nbits = sz * NBBY;

        tdp = xcalloc(sizeof (tdesc_t));
        tdp->t_name = xstrdup(name);
        tdp->t_size = sz;
        tdp->t_id = tid;
        tdp->t_type = INTRINSIC;
        tdp->t_intr = intr;
        tdp->t_flags = TDESC_F_RESOLVED;

        tdesc_add(dw, tdp);

        return (tdp);
}

/*
 * Manufacture a void type.  Used for gcc-emitted stabs, where the lack of a
 * type reference implies a reference to a void type.  A void *, for example
 * will be represented by a pointer die without a DW_AT_type.  CTF requires
 * that pointer nodes point to something, so we'll create a void for use as
 * the target.  Note that the DWARF data may already create a void type.  Ours
 * would then be a duplicate, but it'll be removed in the self-uniquification
 * merge performed at the completion of DWARF->tdesc conversion.
 */
static tdesc_t *
tdesc_intr_void(dwarf_t *dw)
{
        if (dw->dw_void == NULL)
                dw->dw_void = tdesc_intr_common(dw, TID_VOID, "void", 0);

        return (dw->dw_void);
}

static tdesc_t *
tdesc_intr_long(dwarf_t *dw)
{
        if (dw->dw_long == NULL) {
                dw->dw_long = tdesc_intr_common(dw, TID_LONG, "long",
                    dw->dw_ptrsz);
        }

        return (dw->dw_long);
}

/*
 * Used for creating bitfield types.  We create a copy of an existing intrinsic,
 * adjusting the size of the copy to match what the caller requested.  The
 * caller can then use the copy as the type for a bitfield structure member.
 */
static tdesc_t *
tdesc_intr_clone(dwarf_t *dw, tdesc_t *old, size_t bitsz)
{
        tdesc_t *new = xcalloc(sizeof (tdesc_t));

        if (!(old->t_flags & TDESC_F_RESOLVED)) {
                terminate("tdp %u: attempt to make a bit field from an "
                    "unresolved type\n", old->t_id);
        }

        new->t_name = xstrdup(old->t_name);
        new->t_size = old->t_size;
        new->t_id = mfgtid_next(dw);
        new->t_type = INTRINSIC;
        new->t_flags = TDESC_F_RESOLVED;

        new->t_intr = xcalloc(sizeof (intr_t));
        bcopy(old->t_intr, new->t_intr, sizeof (intr_t));
        new->t_intr->intr_nbits = bitsz;

        tdesc_add(dw, new);

        return (new);
}

static void
tdesc_array_create(dwarf_t *dw, Dwarf_Die dim, tdesc_t *arrtdp,
    tdesc_t *dimtdp)
{
        Dwarf_Unsigned uval;
        Dwarf_Signed sval;
        tdesc_t *ctdp = NULL;
        Dwarf_Die dim2;
        ardef_t *ar;

        if ((dim2 = die_sibling(dw, dim)) == NULL) {
                ctdp = arrtdp;
        } else if (die_tag(dw, dim2) == DW_TAG_subrange_type) {
                ctdp = xcalloc(sizeof (tdesc_t));
                ctdp->t_id = mfgtid_next(dw);
                debug(3, "die %llu: creating new type %u for sub-dimension\n",
                    die_off(dw, dim2), ctdp->t_id);
                tdesc_array_create(dw, dim2, arrtdp, ctdp);
        } else {
                terminate("die %llu: unexpected non-subrange node in array\n",
                    die_off(dw, dim2));
        }

        dimtdp->t_type = ARRAY;
        dimtdp->t_ardef = ar = xcalloc(sizeof (ardef_t));

        /*
         * Array bounds can be signed or unsigned, but there are several kinds
         * of signless forms (data1, data2, etc) that take their sign from the
         * routine that is trying to interpret them.  That is, data1 can be
         * either signed or unsigned, depending on whether you use the signed or
         * unsigned accessor function.  GCC will use the signless forms to store
         * unsigned values which have their high bit set, so we need to try to
         * read them first as unsigned to get positive values.  We could also
         * try signed first, falling back to unsigned if we got a negative
         * value.
         */
        if (die_unsigned(dw, dim, DW_AT_upper_bound, &uval, 0))
                ar->ad_nelems = uval + 1;
        else if (die_signed(dw, dim, DW_AT_upper_bound, &sval, 0))
                ar->ad_nelems = sval + 1;
        else
                ar->ad_nelems = 0;

        /*
         * Different compilers use different index types.  Force the type to be
         * a common, known value (long).
         */
        ar->ad_idxtype = tdesc_intr_long(dw);
        ar->ad_contents = ctdp;

        if (ar->ad_contents->t_size != 0) {
                dimtdp->t_size = ar->ad_contents->t_size * ar->ad_nelems;
                dimtdp->t_flags |= TDESC_F_RESOLVED;
        }
}

/*
 * Create a tdesc from an array node.  Some arrays will come with byte size
 * attributes, and thus can be resolved immediately.  Others don't, and will
 * need to wait until the second pass for resolution.
 */
static void
die_array_create(dwarf_t *dw, Dwarf_Die arr, Dwarf_Off off, tdesc_t *tdp)
{
        tdesc_t *arrtdp = die_lookup_pass1(dw, arr, DW_AT_type);
        Dwarf_Unsigned uval;
        Dwarf_Die dim;

        debug(3, "die %llu <%llx>: creating array\n", off, off);

        if ((dim = die_child(dw, arr)) == NULL ||
            die_tag(dw, dim) != DW_TAG_subrange_type)
                terminate("die %llu: failed to retrieve array bounds\n", off);

        tdesc_array_create(dw, dim, arrtdp, tdp);

        if (die_unsigned(dw, arr, DW_AT_byte_size, &uval, 0)) {
                tdesc_t *dimtdp;
                int flags;

                tdp->t_size = uval;

                /*
                 * Ensure that sub-dimensions have sizes too before marking
                 * as resolved.
                 */
                flags = TDESC_F_RESOLVED;
                for (dimtdp = tdp->t_ardef->ad_contents;
                    dimtdp->t_type == ARRAY;
                    dimtdp = dimtdp->t_ardef->ad_contents) {
                        if (!(dimtdp->t_flags & TDESC_F_RESOLVED)) {
                                flags = 0;
                                break;
                        }
                }

                tdp->t_flags |= flags;
        }

        debug(3, "die %llu <%llx>: array nelems %u size %u\n", off, off,
            tdp->t_ardef->ad_nelems, tdp->t_size);
}

/*ARGSUSED1*/
static int
die_array_resolve(tdesc_t *tdp, tdesc_t **tdpp __unused, void *private)
{
        dwarf_t *dw = private;
        size_t sz;

        if (tdp->t_flags & TDESC_F_RESOLVED)
                return (1);

        debug(3, "trying to resolve array %d (cont %d)\n", tdp->t_id,
            tdp->t_ardef->ad_contents->t_id);

        if ((sz = tdesc_size(tdp->t_ardef->ad_contents)) == 0) {
                debug(3, "unable to resolve array %s (%d) contents %d\n",
                    tdesc_name(tdp), tdp->t_id,
                    tdp->t_ardef->ad_contents->t_id);

                dw->dw_nunres++;
                return (1);
        }

        tdp->t_size = sz * tdp->t_ardef->ad_nelems;
        tdp->t_flags |= TDESC_F_RESOLVED;

        debug(3, "resolved array %d: %u bytes\n", tdp->t_id, tdp->t_size);

        return (1);
}

/*ARGSUSED1*/
static int
die_array_failed(tdesc_t *tdp, tdesc_t **tdpp __unused, void *private __unused)
{
        tdesc_t *cont = tdp->t_ardef->ad_contents;

        if (tdp->t_flags & TDESC_F_RESOLVED)
                return (1);

        fprintf(stderr, "Array %d: failed to size contents type %s (%d)\n",
            tdp->t_id, tdesc_name(cont), cont->t_id);

        return (1);
}

/*
 * Most enums (those with members) will be resolved during this first pass.
 * Others - those without members (see the file comment) - won't be, and will
 * need to wait until the second pass when they can be matched with their full
 * definitions.
 */
static void
die_enum_create(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off, tdesc_t *tdp)
{
        Dwarf_Die mem;
        Dwarf_Unsigned uval;
        Dwarf_Signed sval;

        debug(3, "die %llu: creating enum\n", off);

        tdp->t_type = ENUM;

        (void) die_unsigned(dw, die, DW_AT_byte_size, &uval, DW_ATTR_REQ);
        tdp->t_size = uval;

        if ((mem = die_child(dw, die)) != NULL) {
                elist_t **elastp = &tdp->t_emem;

                do {
                        elist_t *el;

                        if (die_tag(dw, mem) != DW_TAG_enumerator) {
                                /* Nested type declaration */
                                die_create_one(dw, mem);
                                continue;
                        }

                        el = xcalloc(sizeof (elist_t));
                        el->el_name = die_name(dw, mem);

                        if (die_signed(dw, mem, DW_AT_const_value, &sval, 0)) {
                                el->el_number = sval;
                        } else if (die_unsigned(dw, mem, DW_AT_const_value,
                            &uval, 0)) {
                                el->el_number = uval;
                        } else {
                                terminate("die %llu: enum %llu: member without "
                                    "value\n", off, die_off(dw, mem));
                        }

                        debug(3, "die %llu: enum %llu: created %s = %d\n", off,
                            die_off(dw, mem), el->el_name, el->el_number);

                        *elastp = el;
                        elastp = &el->el_next;

                } while ((mem = die_sibling(dw, mem)) != NULL);

                hash_add(dw->dw_enumhash, tdp);

                tdp->t_flags |= TDESC_F_RESOLVED;

                if (tdp->t_name != NULL) {
                        iidesc_t *ii = xcalloc(sizeof (iidesc_t));
                        ii->ii_type = II_SOU;
                        ii->ii_name = xstrdup(tdp->t_name);
                        ii->ii_dtype = tdp;

                        iidesc_add(dw->dw_td->td_iihash, ii);
                }
        }
}

static int
die_enum_match(void *arg1, void *arg2)
{
        tdesc_t *tdp = arg1, **fullp = arg2;

        if (tdp->t_emem != NULL) {
                *fullp = tdp;
                return (-1); /* stop the iteration */
        }

        return (0);
}

/*ARGSUSED1*/
static int
die_enum_resolve(tdesc_t *tdp, tdesc_t **tdpp __unused, void *private)
{
        dwarf_t *dw = private;
        tdesc_t *full = NULL;

        if (tdp->t_flags & TDESC_F_RESOLVED)
                return (1);

        (void) hash_find_iter(dw->dw_enumhash, tdp, die_enum_match, &full);

        /*
         * The answer to this one won't change from iteration to iteration,
         * so don't even try.
         */
        if (full == NULL) {
                terminate("tdp %u: enum %s has no members\n", tdp->t_id,
                    tdesc_name(tdp));
        }

        debug(3, "tdp %u: enum %s redirected to %u\n", tdp->t_id,
            tdesc_name(tdp), full->t_id);

        tdp->t_flags |= TDESC_F_RESOLVED;

        return (1);
}

static int
die_fwd_map(void *arg1, void *arg2)
{
        tdesc_t *fwd = arg1, *sou = arg2;

        debug(3, "tdp %u: mapped forward %s to sou %u\n", fwd->t_id,
            tdesc_name(fwd), sou->t_id);
        fwd->t_tdesc = sou;

        return (0);
}

/*
 * Structures and unions will never be resolved during the first pass, as we
 * won't be able to fully determine the member sizes.  The second pass, which
 * have access to sizing information, will be able to complete the resolution.
 */
static void
die_sou_create(dwarf_t *dw, Dwarf_Die str, Dwarf_Off off, tdesc_t *tdp,
    int type, const char *typename)
{
        Dwarf_Unsigned sz, bitsz, bitoff;
#if BYTE_ORDER == _LITTLE_ENDIAN
        Dwarf_Unsigned bysz;
#endif
        Dwarf_Die mem;
        mlist_t *ml, **mlastp;
        iidesc_t *ii;

        tdp->t_type = (die_isdecl(dw, str) ? FORWARD : type);

        debug(3, "die %llu: creating %s %s\n", off,
            (tdp->t_type == FORWARD ? "forward decl" : typename),
            tdesc_name(tdp));

        if (tdp->t_type == FORWARD) {
                hash_add(dw->dw_fwdhash, tdp);
                return;
        }

        (void) hash_find_iter(dw->dw_fwdhash, tdp, die_fwd_map, tdp);

        (void) die_unsigned(dw, str, DW_AT_byte_size, &sz, DW_ATTR_REQ);
        tdp->t_size = sz;

        /*
         * GCC allows empty SOUs as an extension.
         */
        if ((mem = die_child(dw, str)) == NULL) {
                goto out;
        }

        mlastp = &tdp->t_members;

        do {
                Dwarf_Off memoff = die_off(dw, mem);
                Dwarf_Half tag = die_tag(dw, mem);
                Dwarf_Unsigned mloff;

                if (tag != DW_TAG_member) {
                        /* Nested type declaration */
                        die_create_one(dw, mem);
                        continue;
                }

                debug(3, "die %llu: mem %llu: creating member\n", off, memoff);

                ml = xcalloc(sizeof (mlist_t));

                /*
                 * This could be a GCC anon struct/union member, so we'll allow
                 * an empty name, even though nothing can really handle them
                 * properly.  Note that some versions of GCC miss out debug
                 * info for anon structs, though recent versions are fixed (gcc
                 * bug 11816).
                 */
                if ((ml->ml_name = die_name(dw, mem)) == NULL)
                        ml->ml_name = NULL;

                ml->ml_type = die_lookup_pass1(dw, mem, DW_AT_type);

                if (die_mem_offset(dw, mem, DW_AT_data_member_location,
                    &mloff, 0)) {
                        debug(3, "die %llu: got mloff %llx\n", off,
                            (u_longlong_t)mloff);
                        ml->ml_offset = mloff * 8;
                }

                if (die_unsigned(dw, mem, DW_AT_bit_size, &bitsz, 0))
                        ml->ml_size = bitsz;
                else
                        ml->ml_size = tdesc_bitsize(ml->ml_type);

                if (die_unsigned(dw, mem, DW_AT_bit_offset, &bitoff, 0)) {
#if BYTE_ORDER == _BIG_ENDIAN
                        ml->ml_offset += bitoff;
#else
                        /*
                         * Note that Clang 3.4 will sometimes generate
                         * member DIE before generating the DIE for the
                         * member's type. The code can not handle this
                         * properly so that tdesc_bitsize(ml->ml_type) will
                         * return 0 because ml->ml_type is unknown. As a
                         * result, a wrong member offset will be calculated.
                         * To workaround this, we can instead try to
                         * retrieve the value of DW_AT_byte_size attribute
                         * which stores the byte size of the space occupied
                         * by the type. If this attribute exists, its value
                         * should equal to tdesc_bitsize(ml->ml_type)/NBBY.
                         */
                        if (die_unsigned(dw, mem, DW_AT_byte_size, &bysz, 0) &&
                            bysz > 0)
                                ml->ml_offset += bysz * NBBY - bitoff -
                                        ml->ml_size;
                        else
                                ml->ml_offset += tdesc_bitsize(ml->ml_type) -
                                        bitoff - ml->ml_size;
#endif
                }

                debug(3, "die %llu: mem %llu: created \"%s\" (off %u sz %u)\n",
                    off, memoff, ml->ml_name, ml->ml_offset, ml->ml_size);

                *mlastp = ml;
                mlastp = &ml->ml_next;
        } while ((mem = die_sibling(dw, mem)) != NULL);

        /*
         * GCC will attempt to eliminate unused types, thus decreasing the
         * size of the emitted dwarf.  That is, if you declare a foo_t in your
         * header, include said header in your source file, and neglect to
         * actually use (directly or indirectly) the foo_t in the source file,
         * the foo_t won't make it into the emitted DWARF.  So, at least, goes
         * the theory.
         *
         * Occasionally, it'll emit the DW_TAG_structure_type for the foo_t,
         * and then neglect to emit the members.  Strangely, the loner struct
         * tag will always be followed by a proper nested declaration of
         * something else.  This is clearly a bug, but we're not going to have
         * time to get it fixed before this goo goes back, so we'll have to work
         * around it.  If we see a no-membered struct with a nested declaration
         * (i.e. die_child of the struct tag won't be null), we'll ignore it.
         * Being paranoid, we won't simply remove it from the hash.  Instead,
         * we'll decline to create an iidesc for it, thus ensuring that this
         * type won't make it into the output file.  To be safe, we'll also
         * change the name.
         */
        if (tdp->t_members == NULL) {
                const char *old = tdesc_name(tdp);
                size_t newsz = 7 + strlen(old) + 1;
                char *new = xmalloc(newsz);
                (void) snprintf(new, newsz, "orphan %s", old);

                debug(3, "die %llu: worked around %s %s\n", off, typename, old);

                if (tdp->t_name != NULL)
                        free(tdp->t_name);
                tdp->t_name = new;
                return;
        }

out:
        if (tdp->t_name != NULL) {
                ii = xcalloc(sizeof (iidesc_t));
                ii->ii_type = II_SOU;
                ii->ii_name = xstrdup(tdp->t_name);
                ii->ii_dtype = tdp;

                iidesc_add(dw->dw_td->td_iihash, ii);
        }
}

static void
die_struct_create(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off, tdesc_t *tdp)
{
        die_sou_create(dw, die, off, tdp, STRUCT, "struct");
}

static void
die_union_create(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off, tdesc_t *tdp)
{
        die_sou_create(dw, die, off, tdp, UNION, "union");
}

/*ARGSUSED1*/
static int
die_sou_resolve(tdesc_t *tdp, tdesc_t **tdpp __unused, void *private)
{
        dwarf_t *dw = private;
        mlist_t *ml;
        tdesc_t *mt;

        if (tdp->t_flags & TDESC_F_RESOLVED)
                return (1);

        debug(3, "resolving sou %s\n", tdesc_name(tdp));

        for (ml = tdp->t_members; ml != NULL; ml = ml->ml_next) {
                if (ml->ml_size == 0) {
                        mt = tdesc_basetype(ml->ml_type);

                        if ((ml->ml_size = tdesc_bitsize(mt)) != 0)
                                continue;

                        /*
                         * For empty members, or GCC/C99 flexible array
                         * members, a size of 0 is correct.
                         */
                        if (mt->t_members == NULL)
                                continue;
                        if (mt->t_type == ARRAY && mt->t_ardef->ad_nelems == 0)
                                continue;

                        dw->dw_nunres++;
                        return (1);
                }

                if ((mt = tdesc_basetype(ml->ml_type)) == NULL) {
                        dw->dw_nunres++;
                        return (1);
                }

                if (ml->ml_size != 0 && mt->t_type == INTRINSIC &&
                    mt->t_intr->intr_nbits != ml->ml_size) {
                        /*
                         * This member is a bitfield, and needs to reference
                         * an intrinsic type with the same width.  If the
                         * currently-referenced type isn't of the same width,
                         * we'll copy it, adjusting the width of the copy to
                         * the size we'd like.
                         */
                        debug(3, "tdp %u: creating bitfield for %d bits\n",
                            tdp->t_id, ml->ml_size);

                        ml->ml_type = tdesc_intr_clone(dw, mt, ml->ml_size);
                }
        }

        tdp->t_flags |= TDESC_F_RESOLVED;

        return (1);
}

/*ARGSUSED1*/
static int
die_sou_failed(tdesc_t *tdp, tdesc_t **tdpp __unused, void *private __unused)
{
        const char *typename = (tdp->t_type == STRUCT ? "struct" : "union");
        mlist_t *ml;

        if (tdp->t_flags & TDESC_F_RESOLVED)
                return (1);

        for (ml = tdp->t_members; ml != NULL; ml = ml->ml_next) {
                if (ml->ml_size == 0) {
                        fprintf(stderr, "%s %d <%x>: failed to size member \"%s\" "
                            "of type %s (%d <%x>)\n", typename, tdp->t_id,
                            tdp->t_id,
                            ml->ml_name, tdesc_name(ml->ml_type),
                            ml->ml_type->t_id, ml->ml_type->t_id);
                }
        }

        return (1);
}

static void
die_funcptr_create(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off, tdesc_t *tdp)
{
        Dwarf_Attribute attr;
        Dwarf_Half tag;
        Dwarf_Die arg;
        fndef_t *fn;
        int i;

        debug(3, "die %llu <%llx>: creating function pointer\n", off, off);

        /*
         * We'll begin by processing any type definition nodes that may be
         * lurking underneath this one.
         */
        for (arg = die_child(dw, die); arg != NULL;
            arg = die_sibling(dw, arg)) {
                if ((tag = die_tag(dw, arg)) != DW_TAG_formal_parameter &&
                    tag != DW_TAG_unspecified_parameters) {
                        /* Nested type declaration */
                        die_create_one(dw, arg);
                }
        }

        if (die_isdecl(dw, die)) {
                /*
                 * This is a prototype.  We don't add prototypes to the
                 * tree, so we're going to drop the tdesc.  Unfortunately,
                 * it has already been added to the tree.  Nobody will reference
                 * it, though, and it will be leaked.
                 */
                return;
        }

        fn = xcalloc(sizeof (fndef_t));

        tdp->t_type = FUNCTION;

        if ((attr = die_attr(dw, die, DW_AT_type, 0)) != NULL) {
                fn->fn_ret = die_lookup_pass1(dw, die, DW_AT_type);
        } else {
                fn->fn_ret = tdesc_intr_void(dw);
        }

        /*
         * Count the arguments to the function, then read them in.
         */
        for (fn->fn_nargs = 0, arg = die_child(dw, die); arg != NULL;
            arg = die_sibling(dw, arg)) {
                if ((tag = die_tag(dw, arg)) == DW_TAG_formal_parameter)
                        fn->fn_nargs++;
                else if (tag == DW_TAG_unspecified_parameters &&
                    fn->fn_nargs > 0)
                        fn->fn_vargs = 1;
        }

        if (fn->fn_nargs != 0) {
                debug(3, "die %llu: adding %d argument%s\n", off, fn->fn_nargs,
                    (fn->fn_nargs > 1 ? "s" : ""));

                fn->fn_args = xcalloc(sizeof (tdesc_t *) * fn->fn_nargs);
                for (i = 0, arg = die_child(dw, die);
                    arg != NULL && i < (int) fn->fn_nargs;
                    arg = die_sibling(dw, arg)) {
                        if (die_tag(dw, arg) != DW_TAG_formal_parameter)
                                continue;

                        fn->fn_args[i++] = die_lookup_pass1(dw, arg,
                            DW_AT_type);
                }
        }

        tdp->t_fndef = fn;
        tdp->t_flags |= TDESC_F_RESOLVED;
}

/*
 * GCC and DevPro use different names for the base types.  While the terms are
 * the same, they are arranged in a different order.  Some terms, such as int,
 * are implied in one, and explicitly named in the other.  Given a base type
 * as input, this routine will return a common name, along with an intr_t
 * that reflects said name.
 */
static intr_t *
die_base_name_parse(const char *name, char **newp)
{
        char buf[100];
        char const *base;
        char *c;
        int nlong = 0, nshort = 0, nchar = 0, nint = 0;
        int sign = 1;
        char fmt = '\0';
        intr_t *intr;

        if (strlen(name) > sizeof (buf) - 1)
                terminate("base type name \"%s\" is too long\n", name);

        strncpy(buf, name, sizeof (buf));

        for (c = strtok(buf, " "); c != NULL; c = strtok(NULL, " ")) {
                if (strcmp(c, "signed") == 0)
                        sign = 1;
                else if (strcmp(c, "unsigned") == 0)
                        sign = 0;
                else if (strcmp(c, "long") == 0)
                        nlong++;
                else if (strcmp(c, "char") == 0) {
                        nchar++;
                        fmt = 'c';
                } else if (strcmp(c, "short") == 0)
                        nshort++;
                else if (strcmp(c, "int") == 0)
                        nint++;
                else {
                        /*
                         * If we don't recognize any of the tokens, we'll tell
                         * the caller to fall back to the dwarf-provided
                         * encoding information.
                         */
                        return (NULL);
                }
        }

        if (nchar > 1 || nshort > 1 || nint > 1 || nlong > 2)
                return (NULL);

        if (nchar > 0) {
                if (nlong > 0 || nshort > 0 || nint > 0)
                        return (NULL);

                base = "char";

        } else if (nshort > 0) {
                if (nlong > 0)
                        return (NULL);

                base = "short";

        } else if (nlong > 0) {
                base = "long";

        } else {
                base = "int";
        }

        intr = xcalloc(sizeof (intr_t));
        intr->intr_type = INTR_INT;
        intr->intr_signed = sign;
        intr->intr_iformat = fmt;

        snprintf(buf, sizeof (buf), "%s%s%s",
            (sign ? "" : "unsigned "),
            (nlong > 1 ? "long " : ""),
            base);

        *newp = xstrdup(buf);
        return (intr);
}

typedef struct fp_size_map {
        size_t fsm_typesz[2];   /* size of {32,64} type */
        uint_t fsm_enc[3];      /* CTF_FP_* for {bare,cplx,imagry} type */
} fp_size_map_t;

static const fp_size_map_t fp_encodings[] = {
        { { 4, 4 }, { CTF_FP_SINGLE, CTF_FP_CPLX, CTF_FP_IMAGRY } },
        { { 8, 8 }, { CTF_FP_DOUBLE, CTF_FP_DCPLX, CTF_FP_DIMAGRY } },
#ifdef __sparc
        { { 16, 16 }, { CTF_FP_LDOUBLE, CTF_FP_LDCPLX, CTF_FP_LDIMAGRY } },
#else
        { { 12, 16 }, { CTF_FP_LDOUBLE, CTF_FP_LDCPLX, CTF_FP_LDIMAGRY } },
#endif
        { { 0, 0 }, { 0, 0, 0 } }
};

static uint_t
die_base_type2enc(dwarf_t *dw, Dwarf_Off off, Dwarf_Signed enc, size_t sz)
{
        const fp_size_map_t *map = fp_encodings;
        uint_t szidx = dw->dw_ptrsz == sizeof (uint64_t);
        uint_t mult = 1, col = 0;

        if (enc == DW_ATE_complex_float) {
                mult = 2;
                col = 1;
        } else if (enc == DW_ATE_imaginary_float
#if defined(sun)
            || enc == DW_ATE_SUN_imaginary_float
#endif
            )
                col = 2;

        while (map->fsm_typesz[szidx] != 0) {
                if (map->fsm_typesz[szidx] * mult == sz)
                        return (map->fsm_enc[col]);
                map++;
        }

        terminate("die %llu: unrecognized real type size %u\n", off, sz);
        /*NOTREACHED*/
        return (0);
}

static intr_t *
die_base_from_dwarf(dwarf_t *dw, Dwarf_Die base, Dwarf_Off off, size_t sz)
{
        intr_t *intr = xcalloc(sizeof (intr_t));
        Dwarf_Signed enc;

        (void) die_signed(dw, base, DW_AT_encoding, &enc, DW_ATTR_REQ);

        switch (enc) {
        case DW_ATE_unsigned:
        case DW_ATE_address:
                intr->intr_type = INTR_INT;
                break;
        case DW_ATE_unsigned_char:
                intr->intr_type = INTR_INT;
                intr->intr_iformat = 'c';
                break;
        case DW_ATE_signed:
                intr->intr_type = INTR_INT;
                intr->intr_signed = 1;
                break;
        case DW_ATE_signed_char:
                intr->intr_type = INTR_INT;
                intr->intr_signed = 1;
                intr->intr_iformat = 'c';
                break;
        case DW_ATE_boolean:
                intr->intr_type = INTR_INT;
                intr->intr_signed = 1;
                intr->intr_iformat = 'b';
                break;
        case DW_ATE_float:
        case DW_ATE_complex_float:
        case DW_ATE_imaginary_float:
#if defined(sun)
        case DW_ATE_SUN_imaginary_float:
        case DW_ATE_SUN_interval_float:
#endif
                intr->intr_type = INTR_REAL;
                intr->intr_signed = 1;
                intr->intr_fformat = die_base_type2enc(dw, off, enc, sz);
                break;
        default:
                terminate("die %llu: unknown base type encoding 0x%llx\n",
                    off, enc);
        }

        return (intr);
}

static void
die_base_create(dwarf_t *dw, Dwarf_Die base, Dwarf_Off off, tdesc_t *tdp)
{
        Dwarf_Unsigned sz;
        intr_t *intr;
        char *new;

        debug(3, "die %llu: creating base type\n", off);

        /*
         * The compilers have their own clever (internally inconsistent) ideas
         * as to what base types should look like.  Some times gcc will, for
         * example, use DW_ATE_signed_char for char.  Other times, however, it
         * will use DW_ATE_signed.  Needless to say, this causes some problems
         * down the road, particularly with merging.  We do, however, use the
         * DWARF idea of type sizes, as this allows us to avoid caring about
         * the data model.
         */
        (void) die_unsigned(dw, base, DW_AT_byte_size, &sz, DW_ATTR_REQ);

        if (tdp->t_name == NULL)
                terminate("die %llu: base type without name\n", off);

        /* XXX make a name parser for float too */
        if ((intr = die_base_name_parse(tdp->t_name, &new)) != NULL) {
                /* Found it.  We'll use the parsed version */
                debug(3, "die %llu: name \"%s\" remapped to \"%s\"\n", off,
                    tdesc_name(tdp), new);

                free(tdp->t_name);
                tdp->t_name = new;
        } else {
                /*
                 * We didn't recognize the type, so we'll create an intr_t
                 * based on the DWARF data.
                 */
                debug(3, "die %llu: using dwarf data for base \"%s\"\n", off,
                    tdesc_name(tdp));

                intr = die_base_from_dwarf(dw, base, off, sz);
        }

        intr->intr_nbits = sz * 8;

        tdp->t_type = INTRINSIC;
        tdp->t_intr = intr;
        tdp->t_size = sz;

        tdp->t_flags |= TDESC_F_RESOLVED;
}

static void
die_through_create(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off, tdesc_t *tdp,
    int type, const char *typename)
{
        Dwarf_Attribute attr;

        debug(3, "die %llu <%llx>: creating %s type %d\n", off, off, typename, type);

        tdp->t_type = type;

        if ((attr = die_attr(dw, die, DW_AT_type, 0)) != NULL) {
                tdp->t_tdesc = die_lookup_pass1(dw, die, DW_AT_type);
        } else {
                tdp->t_tdesc = tdesc_intr_void(dw);
        }

        if (type == POINTER)
                tdp->t_size = dw->dw_ptrsz;

        tdp->t_flags |= TDESC_F_RESOLVED;

        if (type == TYPEDEF) {
                iidesc_t *ii = xcalloc(sizeof (iidesc_t));
                ii->ii_type = II_TYPE;
                ii->ii_name = xstrdup(tdp->t_name);
                ii->ii_dtype = tdp;

                iidesc_add(dw->dw_td->td_iihash, ii);
        }
}

static void
die_typedef_create(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off, tdesc_t *tdp)
{
        die_through_create(dw, die, off, tdp, TYPEDEF, "typedef");
}

static void
die_const_create(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off, tdesc_t *tdp)
{
        die_through_create(dw, die, off, tdp, CONST, "const");
}

static void
die_pointer_create(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off, tdesc_t *tdp)
{
        die_through_create(dw, die, off, tdp, POINTER, "pointer");
}

static void
die_restrict_create(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off, tdesc_t *tdp)
{
        die_through_create(dw, die, off, tdp, RESTRICT, "restrict");
}

static void
die_volatile_create(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off, tdesc_t *tdp)
{
        die_through_create(dw, die, off, tdp, VOLATILE, "volatile");
}

/*ARGSUSED3*/
static void
die_function_create(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off, tdesc_t *tdp __unused)
{
        Dwarf_Die arg;
        Dwarf_Half tag;
        iidesc_t *ii;
        char *name;

        debug(3, "die %llu <%llx>: creating function definition\n", off, off);

        /*
         * We'll begin by processing any type definition nodes that may be
         * lurking underneath this one.
         */
        for (arg = die_child(dw, die); arg != NULL;
            arg = die_sibling(dw, arg)) {
                if ((tag = die_tag(dw, arg)) != DW_TAG_formal_parameter &&
                    tag != DW_TAG_variable) {
                        /* Nested type declaration */
                        die_create_one(dw, arg);
                }
        }

        if (die_isdecl(dw, die) || (name = die_name(dw, die)) == NULL) {
                /*
                 * We process neither prototypes nor subprograms without
                 * names.
                 */
                return;
        }

        ii = xcalloc(sizeof (iidesc_t));
        ii->ii_type = die_isglobal(dw, die) ? II_GFUN : II_SFUN;
        ii->ii_name = name;
        if (ii->ii_type == II_SFUN)
                ii->ii_owner = xstrdup(dw->dw_cuname);

        debug(3, "die %llu: function %s is %s\n", off, ii->ii_name,
            (ii->ii_type == II_GFUN ? "global" : "static"));

        if (die_attr(dw, die, DW_AT_type, 0) != NULL)
                ii->ii_dtype = die_lookup_pass1(dw, die, DW_AT_type);
        else
                ii->ii_dtype = tdesc_intr_void(dw);

        for (arg = die_child(dw, die); arg != NULL;
            arg = die_sibling(dw, arg)) {
                char *name1;

                debug(3, "die %llu: looking at sub member at %llu\n",
                    off, die_off(dw, die));

                if (die_tag(dw, arg) != DW_TAG_formal_parameter)
                        continue;

                if ((name1 = die_name(dw, arg)) == NULL) {
                        terminate("die %llu: func arg %d has no name\n",
                            off, ii->ii_nargs + 1);
                }

                if (strcmp(name1, "...") == 0) {
                        free(name1);
                        ii->ii_vargs = 1;
                        continue;
                }

                ii->ii_nargs++;
        }

        if (ii->ii_nargs > 0) {
                int i;

                debug(3, "die %llu: function has %d argument%s\n", off,
                    ii->ii_nargs, (ii->ii_nargs == 1 ? "" : "s"));

                ii->ii_args = xcalloc(sizeof (tdesc_t) * ii->ii_nargs);

                for (arg = die_child(dw, die), i = 0;
                    arg != NULL && i < ii->ii_nargs;
                    arg = die_sibling(dw, arg)) {
                        if (die_tag(dw, arg) != DW_TAG_formal_parameter)
                                continue;

                        ii->ii_args[i++] = die_lookup_pass1(dw, arg,
                            DW_AT_type);
                }
        }

        iidesc_add(dw->dw_td->td_iihash, ii);
}

/*ARGSUSED3*/
static void
die_variable_create(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off, tdesc_t *tdp __unused)
{
        iidesc_t *ii;
        char *name;

        debug(3, "die %llu: creating object definition\n", off);

        if (die_isdecl(dw, die) || (name = die_name(dw, die)) == NULL)
                return; /* skip prototypes and nameless objects */

        ii = xcalloc(sizeof (iidesc_t));
        ii->ii_type = die_isglobal(dw, die) ? II_GVAR : II_SVAR;
        ii->ii_name = name;
        ii->ii_dtype = die_lookup_pass1(dw, die, DW_AT_type);
        if (ii->ii_type == II_SVAR)
                ii->ii_owner = xstrdup(dw->dw_cuname);

        iidesc_add(dw->dw_td->td_iihash, ii);
}

/*ARGSUSED2*/
static int
die_fwd_resolve(tdesc_t *fwd, tdesc_t **fwdp, void *private __unused)
{
        if (fwd->t_flags & TDESC_F_RESOLVED)
                return (1);

        if (fwd->t_tdesc != NULL) {
                debug(3, "tdp %u: unforwarded %s\n", fwd->t_id,
                    tdesc_name(fwd));
                *fwdp = fwd->t_tdesc;
        }

        fwd->t_flags |= TDESC_F_RESOLVED;

        return (1);
}

/*ARGSUSED*/
static void
die_lexblk_descend(dwarf_t *dw, Dwarf_Die die, Dwarf_Off off __unused, tdesc_t *tdp __unused)
{
        Dwarf_Die child = die_child(dw, die);

        if (child != NULL)
                die_create(dw, child);
}

/*
 * Used to map the die to a routine which can parse it, using the tag to do the
 * mapping.  While the processing of most tags entails the creation of a tdesc,
 * there are a few which don't - primarily those which result in the creation of
 * iidescs which refer to existing tdescs.
 */

#define DW_F_NOTDP      0x1     /* Don't create a tdesc for the creator */

typedef struct die_creator {
        Dwarf_Half dc_tag;
        uint16_t dc_flags;
        void (*dc_create)(dwarf_t *, Dwarf_Die, Dwarf_Off, tdesc_t *);
} die_creator_t;

static const die_creator_t die_creators[] = {
        { DW_TAG_array_type,            0,              die_array_create },
        { DW_TAG_enumeration_type,      0,              die_enum_create },
        { DW_TAG_lexical_block,         DW_F_NOTDP,     die_lexblk_descend },
        { DW_TAG_pointer_type,          0,              die_pointer_create },
        { DW_TAG_structure_type,        0,              die_struct_create },
        { DW_TAG_subroutine_type,       0,              die_funcptr_create },
        { DW_TAG_typedef,               0,              die_typedef_create },
        { DW_TAG_union_type,            0,              die_union_create },
        { DW_TAG_base_type,             0,              die_base_create },
        { DW_TAG_const_type,            0,              die_const_create },
        { DW_TAG_subprogram,            DW_F_NOTDP,     die_function_create },
        { DW_TAG_variable,              DW_F_NOTDP,     die_variable_create },
        { DW_TAG_volatile_type,         0,              die_volatile_create },
        { DW_TAG_restrict_type,         0,              die_restrict_create },
        { 0, 0, NULL }
};

static const die_creator_t *
die_tag2ctor(Dwarf_Half tag)
{
        const die_creator_t *dc;

        for (dc = die_creators; dc->dc_create != NULL; dc++) {
                if (dc->dc_tag == tag)
                        return (dc);
        }

        return (NULL);
}

static void
die_create_one(dwarf_t *dw, Dwarf_Die die)
{
        Dwarf_Off off = die_off(dw, die);
        const die_creator_t *dc;
        Dwarf_Half tag;
        tdesc_t *tdp;

        debug(3, "die %llu <%llx>: create_one\n", off, off);

        if (off > dw->dw_maxoff) {
                terminate("illegal die offset %llu (max %llu)\n", off,
                    dw->dw_maxoff);
        }

        tag = die_tag(dw, die);

        if ((dc = die_tag2ctor(tag)) == NULL) {
                debug(2, "die %llu: ignoring tag type %x\n", off, tag);
                return;
        }

        if ((tdp = tdesc_lookup(dw, off)) == NULL &&
            !(dc->dc_flags & DW_F_NOTDP)) {
                tdp = xcalloc(sizeof (tdesc_t));
                tdp->t_id = off;
                tdesc_add(dw, tdp);
        }

        if (tdp != NULL)
                tdp->t_name = die_name(dw, die);

        dc->dc_create(dw, die, off, tdp);
}

static void
die_create(dwarf_t *dw, Dwarf_Die die)
{
        do {
                die_create_one(dw, die);
        } while ((die = die_sibling(dw, die)) != NULL);
}

static tdtrav_cb_f die_resolvers[] = {
        NULL,
        NULL,                   /* intrinsic */
        NULL,                   /* pointer */
        die_array_resolve,      /* array */
        NULL,                   /* function */
        die_sou_resolve,        /* struct */
        die_sou_resolve,        /* union */
        die_enum_resolve,       /* enum */
        die_fwd_resolve,        /* forward */
        NULL,                   /* typedef */
        NULL,                   /* typedef unres */
        NULL,                   /* volatile */
        NULL,                   /* const */
        NULL,                   /* restrict */
};

static tdtrav_cb_f die_fail_reporters[] = {
        NULL,
        NULL,                   /* intrinsic */
        NULL,                   /* pointer */
        die_array_failed,       /* array */
        NULL,                   /* function */
        die_sou_failed,         /* struct */
        die_sou_failed,         /* union */
        NULL,                   /* enum */
        NULL,                   /* forward */
        NULL,                   /* typedef */
        NULL,                   /* typedef unres */
        NULL,                   /* volatile */
        NULL,                   /* const */
        NULL,                   /* restrict */
};

static void
die_resolve(dwarf_t *dw)
{
        int last = -1;
        int pass = 0;

        do {
                pass++;
                dw->dw_nunres = 0;

                (void) iitraverse_hash(dw->dw_td->td_iihash,
                    &dw->dw_td->td_curvgen, NULL, NULL, die_resolvers, dw);

                debug(3, "resolve: pass %d, %u left\n", pass, dw->dw_nunres);

                if ((int) dw->dw_nunres == last) {
                        fprintf(stderr, "%s: failed to resolve the following "
                            "types:\n", progname);

                        (void) iitraverse_hash(dw->dw_td->td_iihash,
                            &dw->dw_td->td_curvgen, NULL, NULL,
                            die_fail_reporters, dw);

                        terminate("failed to resolve types\n");
                }

                last = dw->dw_nunres;

        } while (dw->dw_nunres != 0);
}

/*
 * Any object containing a function or object symbol at any scope should also
 * contain DWARF data.
 */
static boolean_t
should_have_dwarf(Elf *elf)
{
        Elf_Scn *scn = NULL;
        Elf_Data *data = NULL;
        GElf_Shdr shdr;
        GElf_Sym sym;
        uint32_t symdx = 0;
        size_t nsyms = 0;
        boolean_t found = B_FALSE;

        while ((scn = elf_nextscn(elf, scn)) != NULL) {
                gelf_getshdr(scn, &shdr);

                if (shdr.sh_type == SHT_SYMTAB) {
                        found = B_TRUE;
                        break;
                }
        }

        if (!found)
                terminate("cannot convert stripped objects\n");

        data = elf_getdata(scn, NULL);
        nsyms = shdr.sh_size / shdr.sh_entsize;

        for (symdx = 0; symdx < nsyms; symdx++) {
                gelf_getsym(data, symdx, &sym);

                if ((GELF_ST_TYPE(sym.st_info) == STT_FUNC) ||
                    (GELF_ST_TYPE(sym.st_info) == STT_TLS) ||
                    (GELF_ST_TYPE(sym.st_info) == STT_OBJECT)) {
                        char *name;

                        name = elf_strptr(elf, shdr.sh_link, sym.st_name);

                        /* Studio emits these local symbols regardless */
                        if ((strcmp(name, "Bbss.bss") != 0) &&
                            (strcmp(name, "Ttbss.bss") != 0) &&
                            (strcmp(name, "Ddata.data") != 0) &&
                            (strcmp(name, "Ttdata.data") != 0) &&
                            (strcmp(name, "Drodata.rodata") != 0))
                                return (B_TRUE);
                }
        }

        return (B_FALSE);
}

/*ARGSUSED*/
int
dw_read(tdata_t *td, Elf *elf, char *filename __unused)
{
        Dwarf_Unsigned abboff, hdrlen, nxthdr;
        Dwarf_Half vers, addrsz;
        Dwarf_Die cu = 0;
        Dwarf_Die child = 0;
        dwarf_t dw;
        char *prod = NULL;
        int rc;

        bzero(&dw, sizeof (dwarf_t));
        dw.dw_td = td;
        dw.dw_ptrsz = elf_ptrsz(elf);
        dw.dw_mfgtid_last = TID_MFGTID_BASE;
        dw.dw_tidhash = hash_new(TDESC_HASH_BUCKETS, tdesc_idhash, tdesc_idcmp);
        dw.dw_fwdhash = hash_new(TDESC_HASH_BUCKETS, tdesc_namehash,
            tdesc_namecmp);
        dw.dw_enumhash = hash_new(TDESC_HASH_BUCKETS, tdesc_namehash,
            tdesc_namecmp);

        if ((rc = dwarf_elf_init(elf, DW_DLC_READ, &dw.dw_dw,
            &dw.dw_err)) == DW_DLV_NO_ENTRY) {
                if (should_have_dwarf(elf)) {
                        errno = ENOENT;
                        return (-1);
                } else {
                        return (0);
                }
        } else if (rc != DW_DLV_OK) {
                if (dwarf_errno(&dw.dw_err) == DW_DLE_DEBUG_INFO_NULL) {
                        /*
                         * There's no type data in the DWARF section, but
                         * libdwarf is too clever to handle that properly.
                         */
                        return (0);
                }

                terminate("failed to initialize DWARF: %s\n",
                    dwarf_errmsg(&dw.dw_err));
        }

        if ((rc = dwarf_next_cu_header(dw.dw_dw, &hdrlen, &vers, &abboff,
            &addrsz, &nxthdr, &dw.dw_err)) != DW_DLV_OK)
                terminate("rc = %d %s\n", rc, dwarf_errmsg(&dw.dw_err));

        if ((cu = die_sibling(&dw, NULL)) == NULL ||
            (((child = die_child(&dw, cu)) == NULL) &&
            should_have_dwarf(elf))) {
                terminate("file does not contain dwarf type data "
                    "(try compiling with -g)\n");
        } else if (child == NULL) {
                return (0);
        }

        dw.dw_maxoff = nxthdr - 1;

        if (dw.dw_maxoff > TID_FILEMAX)
                terminate("file contains too many types\n");

        debug(1, "DWARF version: %d\n", vers);
        if (vers != DWARF_VERSION) {
                terminate("file contains incompatible version %d DWARF code "
                    "(version 2 required)\n", vers);
        }

        if (die_string(&dw, cu, DW_AT_producer, &prod, 0)) {
                debug(1, "DWARF emitter: %s\n", prod);
                free(prod);
        }

        if ((dw.dw_cuname = die_name(&dw, cu)) != NULL) {
                char *base = xstrdup(basename(dw.dw_cuname));
                free(dw.dw_cuname);
                dw.dw_cuname = base;

                debug(1, "CU name: %s\n", dw.dw_cuname);
        }

        if ((child = die_child(&dw, cu)) != NULL)
                die_create(&dw, child);

        if ((rc = dwarf_next_cu_header(dw.dw_dw, &hdrlen, &vers, &abboff,
            &addrsz, &nxthdr, &dw.dw_err)) != DW_DLV_NO_ENTRY)
                terminate("multiple compilation units not supported\n");

        (void) dwarf_finish(&dw.dw_dw, &dw.dw_err);

        die_resolve(&dw);

        cvt_fixups(td, dw.dw_ptrsz);

        /* leak the dwarf_t */

        return (0);
}