1033 lines
27 KiB
C
1033 lines
27 KiB
C
/* Subroutines needed for unwinding stack frames for exception handling. */
|
||
/* Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
|
||
Free Software Foundation, Inc.
|
||
Contributed by Jason Merrill <jason@cygnus.com>.
|
||
|
||
This file is part of GCC.
|
||
|
||
GCC 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 2, or (at your option) any later
|
||
version.
|
||
|
||
In addition to the permissions in the GNU General Public License, the
|
||
Free Software Foundation gives you unlimited permission to link the
|
||
compiled version of this file into combinations with other programs,
|
||
and to distribute those combinations without any restriction coming
|
||
from the use of this file. (The General Public License restrictions
|
||
do apply in other respects; for example, they cover modification of
|
||
the file, and distribution when not linked into a combine
|
||
executable.)
|
||
|
||
GCC 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 GCC; see the file COPYING. If not, write to the Free
|
||
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
|
||
02111-1307, USA. */
|
||
|
||
#ifndef _Unwind_Find_FDE
|
||
#include "tconfig.h"
|
||
#include "tsystem.h"
|
||
#include "coretypes.h"
|
||
#include "tm.h"
|
||
#include "dwarf2.h"
|
||
#include "unwind.h"
|
||
#define NO_BASE_OF_ENCODED_VALUE
|
||
#include "unwind-pe.h"
|
||
#include "unwind-dw2-fde.h"
|
||
#include "gthr.h"
|
||
#endif
|
||
|
||
/* The unseen_objects list contains objects that have been registered
|
||
but not yet categorized in any way. The seen_objects list has had
|
||
it's pc_begin and count fields initialized at minimum, and is sorted
|
||
by decreasing value of pc_begin. */
|
||
static struct object *unseen_objects;
|
||
static struct object *seen_objects;
|
||
|
||
#ifdef __GTHREAD_MUTEX_INIT
|
||
static __gthread_mutex_t object_mutex = __GTHREAD_MUTEX_INIT;
|
||
#else
|
||
static __gthread_mutex_t object_mutex;
|
||
#endif
|
||
|
||
#ifdef __GTHREAD_MUTEX_INIT_FUNCTION
|
||
static void
|
||
init_object_mutex (void)
|
||
{
|
||
__GTHREAD_MUTEX_INIT_FUNCTION (&object_mutex);
|
||
}
|
||
|
||
static void
|
||
init_object_mutex_once (void)
|
||
{
|
||
static __gthread_once_t once = __GTHREAD_ONCE_INIT;
|
||
__gthread_once (&once, init_object_mutex);
|
||
}
|
||
#else
|
||
#define init_object_mutex_once()
|
||
#endif
|
||
|
||
/* Called from crtbegin.o to register the unwind info for an object. */
|
||
|
||
void
|
||
__register_frame_info_bases (const void *begin, struct object *ob,
|
||
void *tbase, void *dbase)
|
||
{
|
||
/* If .eh_frame is empty, don't register at all. */
|
||
if ((uword *) begin == 0 || *(uword *) begin == 0)
|
||
return;
|
||
|
||
ob->pc_begin = (void *)-1;
|
||
ob->tbase = tbase;
|
||
ob->dbase = dbase;
|
||
ob->u.single = begin;
|
||
ob->s.i = 0;
|
||
ob->s.b.encoding = DW_EH_PE_omit;
|
||
#ifdef DWARF2_OBJECT_END_PTR_EXTENSION
|
||
ob->fde_end = NULL;
|
||
#endif
|
||
|
||
init_object_mutex_once ();
|
||
__gthread_mutex_lock (&object_mutex);
|
||
|
||
ob->next = unseen_objects;
|
||
unseen_objects = ob;
|
||
|
||
__gthread_mutex_unlock (&object_mutex);
|
||
}
|
||
|
||
void
|
||
__register_frame_info (const void *begin, struct object *ob)
|
||
{
|
||
__register_frame_info_bases (begin, ob, 0, 0);
|
||
}
|
||
|
||
void
|
||
__register_frame (void *begin)
|
||
{
|
||
struct object *ob;
|
||
|
||
/* If .eh_frame is empty, don't register at all. */
|
||
if (*(uword *) begin == 0)
|
||
return;
|
||
|
||
ob = malloc (sizeof (struct object));
|
||
__register_frame_info (begin, ob);
|
||
}
|
||
|
||
/* Similar, but BEGIN is actually a pointer to a table of unwind entries
|
||
for different translation units. Called from the file generated by
|
||
collect2. */
|
||
|
||
void
|
||
__register_frame_info_table_bases (void *begin, struct object *ob,
|
||
void *tbase, void *dbase)
|
||
{
|
||
ob->pc_begin = (void *)-1;
|
||
ob->tbase = tbase;
|
||
ob->dbase = dbase;
|
||
ob->u.array = begin;
|
||
ob->s.i = 0;
|
||
ob->s.b.from_array = 1;
|
||
ob->s.b.encoding = DW_EH_PE_omit;
|
||
|
||
init_object_mutex_once ();
|
||
__gthread_mutex_lock (&object_mutex);
|
||
|
||
ob->next = unseen_objects;
|
||
unseen_objects = ob;
|
||
|
||
__gthread_mutex_unlock (&object_mutex);
|
||
}
|
||
|
||
void
|
||
__register_frame_info_table (void *begin, struct object *ob)
|
||
{
|
||
__register_frame_info_table_bases (begin, ob, 0, 0);
|
||
}
|
||
|
||
void
|
||
__register_frame_table (void *begin)
|
||
{
|
||
struct object *ob = malloc (sizeof (struct object));
|
||
__register_frame_info_table (begin, ob);
|
||
}
|
||
|
||
/* Called from crtbegin.o to deregister the unwind info for an object. */
|
||
/* ??? Glibc has for a while now exported __register_frame_info and
|
||
__deregister_frame_info. If we call __register_frame_info_bases
|
||
from crtbegin (wherein it is declared weak), and this object does
|
||
not get pulled from libgcc.a for other reasons, then the
|
||
invocation of __deregister_frame_info will be resolved from glibc.
|
||
Since the registration did not happen there, we'll abort.
|
||
|
||
Therefore, declare a new deregistration entry point that does the
|
||
exact same thing, but will resolve to the same library as
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||
implements __register_frame_info_bases. */
|
||
|
||
void *
|
||
__deregister_frame_info_bases (const void *begin)
|
||
{
|
||
struct object **p;
|
||
struct object *ob = 0;
|
||
|
||
/* If .eh_frame is empty, we haven't registered. */
|
||
if ((uword *) begin == 0 || *(uword *) begin == 0)
|
||
return ob;
|
||
|
||
init_object_mutex_once ();
|
||
__gthread_mutex_lock (&object_mutex);
|
||
|
||
for (p = &unseen_objects; *p ; p = &(*p)->next)
|
||
if ((*p)->u.single == begin)
|
||
{
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||
ob = *p;
|
||
*p = ob->next;
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||
goto out;
|
||
}
|
||
|
||
for (p = &seen_objects; *p ; p = &(*p)->next)
|
||
if ((*p)->s.b.sorted)
|
||
{
|
||
if ((*p)->u.sort->orig_data == begin)
|
||
{
|
||
ob = *p;
|
||
*p = ob->next;
|
||
free (ob->u.sort);
|
||
goto out;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
if ((*p)->u.single == begin)
|
||
{
|
||
ob = *p;
|
||
*p = ob->next;
|
||
goto out;
|
||
}
|
||
}
|
||
|
||
__gthread_mutex_unlock (&object_mutex);
|
||
abort ();
|
||
|
||
out:
|
||
__gthread_mutex_unlock (&object_mutex);
|
||
return (void *) ob;
|
||
}
|
||
|
||
void *
|
||
__deregister_frame_info (const void *begin)
|
||
{
|
||
return __deregister_frame_info_bases (begin);
|
||
}
|
||
|
||
void
|
||
__deregister_frame (void *begin)
|
||
{
|
||
/* If .eh_frame is empty, we haven't registered. */
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||
if (*(uword *) begin != 0)
|
||
free (__deregister_frame_info (begin));
|
||
}
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||
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||
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||
/* Like base_of_encoded_value, but take the base from a struct object
|
||
instead of an _Unwind_Context. */
|
||
|
||
static _Unwind_Ptr
|
||
base_from_object (unsigned char encoding, struct object *ob)
|
||
{
|
||
if (encoding == DW_EH_PE_omit)
|
||
return 0;
|
||
|
||
switch (encoding & 0x70)
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||
{
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||
case DW_EH_PE_absptr:
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||
case DW_EH_PE_pcrel:
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||
case DW_EH_PE_aligned:
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||
return 0;
|
||
|
||
case DW_EH_PE_textrel:
|
||
return (_Unwind_Ptr) ob->tbase;
|
||
case DW_EH_PE_datarel:
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||
return (_Unwind_Ptr) ob->dbase;
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||
}
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||
abort ();
|
||
}
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||
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||
/* Return the FDE pointer encoding from the CIE. */
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||
/* ??? This is a subset of extract_cie_info from unwind-dw2.c. */
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||
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||
static int
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||
get_cie_encoding (const struct dwarf_cie *cie)
|
||
{
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||
const unsigned char *aug, *p;
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||
_Unwind_Ptr dummy;
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||
_Unwind_Word utmp;
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||
_Unwind_Sword stmp;
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||
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||
aug = cie->augmentation;
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||
if (aug[0] != 'z')
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||
return DW_EH_PE_absptr;
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||
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||
p = aug + strlen ((const char *)aug) + 1; /* Skip the augmentation string. */
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||
p = read_uleb128 (p, &utmp); /* Skip code alignment. */
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p = read_sleb128 (p, &stmp); /* Skip data alignment. */
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||
if (cie->version == 1) /* Skip return address column. */
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||
p++;
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||
else
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||
p = read_uleb128 (p, &utmp);
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||
|
||
aug++; /* Skip 'z' */
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||
p = read_uleb128 (p, &utmp); /* Skip augmentation length. */
|
||
while (1)
|
||
{
|
||
/* This is what we're looking for. */
|
||
if (*aug == 'R')
|
||
return *p;
|
||
/* Personality encoding and pointer. */
|
||
else if (*aug == 'P')
|
||
{
|
||
/* ??? Avoid dereferencing indirect pointers, since we're
|
||
faking the base address. Gotta keep DW_EH_PE_aligned
|
||
intact, however. */
|
||
p = read_encoded_value_with_base (*p & 0x7F, 0, p + 1, &dummy);
|
||
}
|
||
/* LSDA encoding. */
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||
else if (*aug == 'L')
|
||
p++;
|
||
/* Otherwise end of string, or unknown augmentation. */
|
||
else
|
||
return DW_EH_PE_absptr;
|
||
aug++;
|
||
}
|
||
}
|
||
|
||
static inline int
|
||
get_fde_encoding (const struct dwarf_fde *f)
|
||
{
|
||
return get_cie_encoding (get_cie (f));
|
||
}
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||
|
||
|
||
/* Sorting an array of FDEs by address.
|
||
(Ideally we would have the linker sort the FDEs so we don't have to do
|
||
it at run time. But the linkers are not yet prepared for this.) */
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||
|
||
/* Comparison routines. Three variants of increasing complexity. */
|
||
|
||
static int
|
||
fde_unencoded_compare (struct object *ob __attribute__((unused)),
|
||
const fde *x, const fde *y)
|
||
{
|
||
_Unwind_Ptr x_ptr = *(_Unwind_Ptr *) x->pc_begin;
|
||
_Unwind_Ptr y_ptr = *(_Unwind_Ptr *) y->pc_begin;
|
||
|
||
if (x_ptr > y_ptr)
|
||
return 1;
|
||
if (x_ptr < y_ptr)
|
||
return -1;
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
fde_single_encoding_compare (struct object *ob, const fde *x, const fde *y)
|
||
{
|
||
_Unwind_Ptr base, x_ptr, y_ptr;
|
||
|
||
base = base_from_object (ob->s.b.encoding, ob);
|
||
read_encoded_value_with_base (ob->s.b.encoding, base, x->pc_begin, &x_ptr);
|
||
read_encoded_value_with_base (ob->s.b.encoding, base, y->pc_begin, &y_ptr);
|
||
|
||
if (x_ptr > y_ptr)
|
||
return 1;
|
||
if (x_ptr < y_ptr)
|
||
return -1;
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
fde_mixed_encoding_compare (struct object *ob, const fde *x, const fde *y)
|
||
{
|
||
int x_encoding, y_encoding;
|
||
_Unwind_Ptr x_ptr, y_ptr;
|
||
|
||
x_encoding = get_fde_encoding (x);
|
||
read_encoded_value_with_base (x_encoding, base_from_object (x_encoding, ob),
|
||
x->pc_begin, &x_ptr);
|
||
|
||
y_encoding = get_fde_encoding (y);
|
||
read_encoded_value_with_base (y_encoding, base_from_object (y_encoding, ob),
|
||
y->pc_begin, &y_ptr);
|
||
|
||
if (x_ptr > y_ptr)
|
||
return 1;
|
||
if (x_ptr < y_ptr)
|
||
return -1;
|
||
return 0;
|
||
}
|
||
|
||
typedef int (*fde_compare_t) (struct object *, const fde *, const fde *);
|
||
|
||
|
||
/* This is a special mix of insertion sort and heap sort, optimized for
|
||
the data sets that actually occur. They look like
|
||
101 102 103 127 128 105 108 110 190 111 115 119 125 160 126 129 130.
|
||
I.e. a linearly increasing sequence (coming from functions in the text
|
||
section), with additionally a few unordered elements (coming from functions
|
||
in gnu_linkonce sections) whose values are higher than the values in the
|
||
surrounding linear sequence (but not necessarily higher than the values
|
||
at the end of the linear sequence!).
|
||
The worst-case total run time is O(N) + O(n log (n)), where N is the
|
||
total number of FDEs and n is the number of erratic ones. */
|
||
|
||
struct fde_accumulator
|
||
{
|
||
struct fde_vector *linear;
|
||
struct fde_vector *erratic;
|
||
};
|
||
|
||
static inline int
|
||
start_fde_sort (struct fde_accumulator *accu, size_t count)
|
||
{
|
||
size_t size;
|
||
if (! count)
|
||
return 0;
|
||
|
||
size = sizeof (struct fde_vector) + sizeof (const fde *) * count;
|
||
if ((accu->linear = malloc (size)))
|
||
{
|
||
accu->linear->count = 0;
|
||
if ((accu->erratic = malloc (size)))
|
||
accu->erratic->count = 0;
|
||
return 1;
|
||
}
|
||
else
|
||
return 0;
|
||
}
|
||
|
||
static inline void
|
||
fde_insert (struct fde_accumulator *accu, const fde *this_fde)
|
||
{
|
||
if (accu->linear)
|
||
accu->linear->array[accu->linear->count++] = this_fde;
|
||
}
|
||
|
||
/* Split LINEAR into a linear sequence with low values and an erratic
|
||
sequence with high values, put the linear one (of longest possible
|
||
length) into LINEAR and the erratic one into ERRATIC. This is O(N).
|
||
|
||
Because the longest linear sequence we are trying to locate within the
|
||
incoming LINEAR array can be interspersed with (high valued) erratic
|
||
entries. We construct a chain indicating the sequenced entries.
|
||
To avoid having to allocate this chain, we overlay it onto the space of
|
||
the ERRATIC array during construction. A final pass iterates over the
|
||
chain to determine what should be placed in the ERRATIC array, and
|
||
what is the linear sequence. This overlay is safe from aliasing. */
|
||
|
||
static inline void
|
||
fde_split (struct object *ob, fde_compare_t fde_compare,
|
||
struct fde_vector *linear, struct fde_vector *erratic)
|
||
{
|
||
static const fde *marker;
|
||
size_t count = linear->count;
|
||
const fde **chain_end = ▮
|
||
size_t i, j, k;
|
||
|
||
/* This should optimize out, but it is wise to make sure this assumption
|
||
is correct. Should these have different sizes, we cannot cast between
|
||
them and the overlaying onto ERRATIC will not work. */
|
||
if (sizeof (const fde *) != sizeof (const fde **))
|
||
abort ();
|
||
|
||
for (i = 0; i < count; i++)
|
||
{
|
||
const fde **probe;
|
||
|
||
for (probe = chain_end;
|
||
probe != &marker && fde_compare (ob, linear->array[i], *probe) < 0;
|
||
probe = chain_end)
|
||
{
|
||
chain_end = (const fde **) erratic->array[probe - linear->array];
|
||
erratic->array[probe - linear->array] = NULL;
|
||
}
|
||
erratic->array[i] = (const fde *) chain_end;
|
||
chain_end = &linear->array[i];
|
||
}
|
||
|
||
/* Each entry in LINEAR which is part of the linear sequence we have
|
||
discovered will correspond to a non-NULL entry in the chain we built in
|
||
the ERRATIC array. */
|
||
for (i = j = k = 0; i < count; i++)
|
||
if (erratic->array[i])
|
||
linear->array[j++] = linear->array[i];
|
||
else
|
||
erratic->array[k++] = linear->array[i];
|
||
linear->count = j;
|
||
erratic->count = k;
|
||
}
|
||
|
||
#define SWAP(x,y) do { const fde * tmp = x; x = y; y = tmp; } while (0)
|
||
|
||
/* Convert a semi-heap to a heap. A semi-heap is a heap except possibly
|
||
for the first (root) node; push it down to its rightful place. */
|
||
|
||
static void
|
||
frame_downheap (struct object *ob, fde_compare_t fde_compare, const fde **a,
|
||
int lo, int hi)
|
||
{
|
||
int i, j;
|
||
|
||
for (i = lo, j = 2*i+1;
|
||
j < hi;
|
||
j = 2*i+1)
|
||
{
|
||
if (j+1 < hi && fde_compare (ob, a[j], a[j+1]) < 0)
|
||
++j;
|
||
|
||
if (fde_compare (ob, a[i], a[j]) < 0)
|
||
{
|
||
SWAP (a[i], a[j]);
|
||
i = j;
|
||
}
|
||
else
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* This is O(n log(n)). BSD/OS defines heapsort in stdlib.h, so we must
|
||
use a name that does not conflict. */
|
||
|
||
static void
|
||
frame_heapsort (struct object *ob, fde_compare_t fde_compare,
|
||
struct fde_vector *erratic)
|
||
{
|
||
/* For a description of this algorithm, see:
|
||
Samuel P. Harbison, Guy L. Steele Jr.: C, a reference manual, 2nd ed.,
|
||
p. 60-61. */
|
||
const fde ** a = erratic->array;
|
||
/* A portion of the array is called a "heap" if for all i>=0:
|
||
If i and 2i+1 are valid indices, then a[i] >= a[2i+1].
|
||
If i and 2i+2 are valid indices, then a[i] >= a[2i+2]. */
|
||
size_t n = erratic->count;
|
||
int m;
|
||
|
||
/* Expand our heap incrementally from the end of the array, heapifying
|
||
each resulting semi-heap as we go. After each step, a[m] is the top
|
||
of a heap. */
|
||
for (m = n/2-1; m >= 0; --m)
|
||
frame_downheap (ob, fde_compare, a, m, n);
|
||
|
||
/* Shrink our heap incrementally from the end of the array, first
|
||
swapping out the largest element a[0] and then re-heapifying the
|
||
resulting semi-heap. After each step, a[0..m) is a heap. */
|
||
for (m = n-1; m >= 1; --m)
|
||
{
|
||
SWAP (a[0], a[m]);
|
||
frame_downheap (ob, fde_compare, a, 0, m);
|
||
}
|
||
#undef SWAP
|
||
}
|
||
|
||
/* Merge V1 and V2, both sorted, and put the result into V1. */
|
||
static inline void
|
||
fde_merge (struct object *ob, fde_compare_t fde_compare,
|
||
struct fde_vector *v1, struct fde_vector *v2)
|
||
{
|
||
size_t i1, i2;
|
||
const fde * fde2;
|
||
|
||
i2 = v2->count;
|
||
if (i2 > 0)
|
||
{
|
||
i1 = v1->count;
|
||
do
|
||
{
|
||
i2--;
|
||
fde2 = v2->array[i2];
|
||
while (i1 > 0 && fde_compare (ob, v1->array[i1-1], fde2) > 0)
|
||
{
|
||
v1->array[i1+i2] = v1->array[i1-1];
|
||
i1--;
|
||
}
|
||
v1->array[i1+i2] = fde2;
|
||
}
|
||
while (i2 > 0);
|
||
v1->count += v2->count;
|
||
}
|
||
}
|
||
|
||
static inline void
|
||
end_fde_sort (struct object *ob, struct fde_accumulator *accu, size_t count)
|
||
{
|
||
fde_compare_t fde_compare;
|
||
|
||
if (accu->linear && accu->linear->count != count)
|
||
abort ();
|
||
|
||
if (ob->s.b.mixed_encoding)
|
||
fde_compare = fde_mixed_encoding_compare;
|
||
else if (ob->s.b.encoding == DW_EH_PE_absptr)
|
||
fde_compare = fde_unencoded_compare;
|
||
else
|
||
fde_compare = fde_single_encoding_compare;
|
||
|
||
if (accu->erratic)
|
||
{
|
||
fde_split (ob, fde_compare, accu->linear, accu->erratic);
|
||
if (accu->linear->count + accu->erratic->count != count)
|
||
abort ();
|
||
frame_heapsort (ob, fde_compare, accu->erratic);
|
||
fde_merge (ob, fde_compare, accu->linear, accu->erratic);
|
||
free (accu->erratic);
|
||
}
|
||
else
|
||
{
|
||
/* We've not managed to malloc an erratic array,
|
||
so heap sort in the linear one. */
|
||
frame_heapsort (ob, fde_compare, accu->linear);
|
||
}
|
||
}
|
||
|
||
|
||
/* Update encoding, mixed_encoding, and pc_begin for OB for the
|
||
fde array beginning at THIS_FDE. Return the number of fdes
|
||
encountered along the way. */
|
||
|
||
static size_t
|
||
classify_object_over_fdes (struct object *ob, const fde *this_fde)
|
||
{
|
||
const struct dwarf_cie *last_cie = 0;
|
||
size_t count = 0;
|
||
int encoding = DW_EH_PE_absptr;
|
||
_Unwind_Ptr base = 0;
|
||
|
||
for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde))
|
||
{
|
||
const struct dwarf_cie *this_cie;
|
||
_Unwind_Ptr mask, pc_begin;
|
||
|
||
/* Skip CIEs. */
|
||
if (this_fde->CIE_delta == 0)
|
||
continue;
|
||
|
||
/* Determine the encoding for this FDE. Note mixed encoded
|
||
objects for later. */
|
||
this_cie = get_cie (this_fde);
|
||
if (this_cie != last_cie)
|
||
{
|
||
last_cie = this_cie;
|
||
encoding = get_cie_encoding (this_cie);
|
||
base = base_from_object (encoding, ob);
|
||
if (ob->s.b.encoding == DW_EH_PE_omit)
|
||
ob->s.b.encoding = encoding;
|
||
else if (ob->s.b.encoding != encoding)
|
||
ob->s.b.mixed_encoding = 1;
|
||
}
|
||
|
||
read_encoded_value_with_base (encoding, base, this_fde->pc_begin,
|
||
&pc_begin);
|
||
|
||
/* Take care to ignore link-once functions that were removed.
|
||
In these cases, the function address will be NULL, but if
|
||
the encoding is smaller than a pointer a true NULL may not
|
||
be representable. Assume 0 in the representable bits is NULL. */
|
||
mask = size_of_encoded_value (encoding);
|
||
if (mask < sizeof (void *))
|
||
mask = (1L << (mask << 3)) - 1;
|
||
else
|
||
mask = -1;
|
||
|
||
if ((pc_begin & mask) == 0)
|
||
continue;
|
||
|
||
count += 1;
|
||
if ((void *) pc_begin < ob->pc_begin)
|
||
ob->pc_begin = (void *) pc_begin;
|
||
}
|
||
|
||
return count;
|
||
}
|
||
|
||
static void
|
||
add_fdes (struct object *ob, struct fde_accumulator *accu, const fde *this_fde)
|
||
{
|
||
const struct dwarf_cie *last_cie = 0;
|
||
int encoding = ob->s.b.encoding;
|
||
_Unwind_Ptr base = base_from_object (ob->s.b.encoding, ob);
|
||
|
||
for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde))
|
||
{
|
||
const struct dwarf_cie *this_cie;
|
||
|
||
/* Skip CIEs. */
|
||
if (this_fde->CIE_delta == 0)
|
||
continue;
|
||
|
||
if (ob->s.b.mixed_encoding)
|
||
{
|
||
/* Determine the encoding for this FDE. Note mixed encoded
|
||
objects for later. */
|
||
this_cie = get_cie (this_fde);
|
||
if (this_cie != last_cie)
|
||
{
|
||
last_cie = this_cie;
|
||
encoding = get_cie_encoding (this_cie);
|
||
base = base_from_object (encoding, ob);
|
||
}
|
||
}
|
||
|
||
if (encoding == DW_EH_PE_absptr)
|
||
{
|
||
if (*(_Unwind_Ptr *) this_fde->pc_begin == 0)
|
||
continue;
|
||
}
|
||
else
|
||
{
|
||
_Unwind_Ptr pc_begin, mask;
|
||
|
||
read_encoded_value_with_base (encoding, base, this_fde->pc_begin,
|
||
&pc_begin);
|
||
|
||
/* Take care to ignore link-once functions that were removed.
|
||
In these cases, the function address will be NULL, but if
|
||
the encoding is smaller than a pointer a true NULL may not
|
||
be representable. Assume 0 in the representable bits is NULL. */
|
||
mask = size_of_encoded_value (encoding);
|
||
if (mask < sizeof (void *))
|
||
mask = (1L << (mask << 3)) - 1;
|
||
else
|
||
mask = -1;
|
||
|
||
if ((pc_begin & mask) == 0)
|
||
continue;
|
||
}
|
||
|
||
fde_insert (accu, this_fde);
|
||
}
|
||
}
|
||
|
||
/* Set up a sorted array of pointers to FDEs for a loaded object. We
|
||
count up the entries before allocating the array because it's likely to
|
||
be faster. We can be called multiple times, should we have failed to
|
||
allocate a sorted fde array on a previous occasion. */
|
||
|
||
static inline void
|
||
init_object (struct object* ob)
|
||
{
|
||
struct fde_accumulator accu;
|
||
size_t count;
|
||
|
||
count = ob->s.b.count;
|
||
if (count == 0)
|
||
{
|
||
if (ob->s.b.from_array)
|
||
{
|
||
fde **p = ob->u.array;
|
||
for (count = 0; *p; ++p)
|
||
count += classify_object_over_fdes (ob, *p);
|
||
}
|
||
else
|
||
count = classify_object_over_fdes (ob, ob->u.single);
|
||
|
||
/* The count field we have in the main struct object is somewhat
|
||
limited, but should suffice for virtually all cases. If the
|
||
counted value doesn't fit, re-write a zero. The worst that
|
||
happens is that we re-count next time -- admittedly non-trivial
|
||
in that this implies some 2M fdes, but at least we function. */
|
||
ob->s.b.count = count;
|
||
if (ob->s.b.count != count)
|
||
ob->s.b.count = 0;
|
||
}
|
||
|
||
if (!start_fde_sort (&accu, count))
|
||
return;
|
||
|
||
if (ob->s.b.from_array)
|
||
{
|
||
fde **p;
|
||
for (p = ob->u.array; *p; ++p)
|
||
add_fdes (ob, &accu, *p);
|
||
}
|
||
else
|
||
add_fdes (ob, &accu, ob->u.single);
|
||
|
||
end_fde_sort (ob, &accu, count);
|
||
|
||
/* Save the original fde pointer, since this is the key by which the
|
||
DSO will deregister the object. */
|
||
accu.linear->orig_data = ob->u.single;
|
||
ob->u.sort = accu.linear;
|
||
|
||
ob->s.b.sorted = 1;
|
||
}
|
||
|
||
/* A linear search through a set of FDEs for the given PC. This is
|
||
used when there was insufficient memory to allocate and sort an
|
||
array. */
|
||
|
||
static const fde *
|
||
linear_search_fdes (struct object *ob, const fde *this_fde, void *pc)
|
||
{
|
||
const struct dwarf_cie *last_cie = 0;
|
||
int encoding = ob->s.b.encoding;
|
||
_Unwind_Ptr base = base_from_object (ob->s.b.encoding, ob);
|
||
|
||
for (; ! last_fde (ob, this_fde); this_fde = next_fde (this_fde))
|
||
{
|
||
const struct dwarf_cie *this_cie;
|
||
_Unwind_Ptr pc_begin, pc_range;
|
||
|
||
/* Skip CIEs. */
|
||
if (this_fde->CIE_delta == 0)
|
||
continue;
|
||
|
||
if (ob->s.b.mixed_encoding)
|
||
{
|
||
/* Determine the encoding for this FDE. Note mixed encoded
|
||
objects for later. */
|
||
this_cie = get_cie (this_fde);
|
||
if (this_cie != last_cie)
|
||
{
|
||
last_cie = this_cie;
|
||
encoding = get_cie_encoding (this_cie);
|
||
base = base_from_object (encoding, ob);
|
||
}
|
||
}
|
||
|
||
if (encoding == DW_EH_PE_absptr)
|
||
{
|
||
pc_begin = ((_Unwind_Ptr *) this_fde->pc_begin)[0];
|
||
pc_range = ((_Unwind_Ptr *) this_fde->pc_begin)[1];
|
||
if (pc_begin == 0)
|
||
continue;
|
||
}
|
||
else
|
||
{
|
||
_Unwind_Ptr mask;
|
||
const unsigned char *p;
|
||
|
||
p = read_encoded_value_with_base (encoding, base,
|
||
this_fde->pc_begin, &pc_begin);
|
||
read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range);
|
||
|
||
/* Take care to ignore link-once functions that were removed.
|
||
In these cases, the function address will be NULL, but if
|
||
the encoding is smaller than a pointer a true NULL may not
|
||
be representable. Assume 0 in the representable bits is NULL. */
|
||
mask = size_of_encoded_value (encoding);
|
||
if (mask < sizeof (void *))
|
||
mask = (1L << (mask << 3)) - 1;
|
||
else
|
||
mask = -1;
|
||
|
||
if ((pc_begin & mask) == 0)
|
||
continue;
|
||
}
|
||
|
||
if ((_Unwind_Ptr) pc - pc_begin < pc_range)
|
||
return this_fde;
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
/* Binary search for an FDE containing the given PC. Here are three
|
||
implementations of increasing complexity. */
|
||
|
||
static inline const fde *
|
||
binary_search_unencoded_fdes (struct object *ob, void *pc)
|
||
{
|
||
struct fde_vector *vec = ob->u.sort;
|
||
size_t lo, hi;
|
||
|
||
for (lo = 0, hi = vec->count; lo < hi; )
|
||
{
|
||
size_t i = (lo + hi) / 2;
|
||
const fde *f = vec->array[i];
|
||
void *pc_begin;
|
||
uaddr pc_range;
|
||
|
||
pc_begin = ((void **) f->pc_begin)[0];
|
||
pc_range = ((uaddr *) f->pc_begin)[1];
|
||
|
||
if (pc < pc_begin)
|
||
hi = i;
|
||
else if (pc >= pc_begin + pc_range)
|
||
lo = i + 1;
|
||
else
|
||
return f;
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
static inline const fde *
|
||
binary_search_single_encoding_fdes (struct object *ob, void *pc)
|
||
{
|
||
struct fde_vector *vec = ob->u.sort;
|
||
int encoding = ob->s.b.encoding;
|
||
_Unwind_Ptr base = base_from_object (encoding, ob);
|
||
size_t lo, hi;
|
||
|
||
for (lo = 0, hi = vec->count; lo < hi; )
|
||
{
|
||
size_t i = (lo + hi) / 2;
|
||
const fde *f = vec->array[i];
|
||
_Unwind_Ptr pc_begin, pc_range;
|
||
const unsigned char *p;
|
||
|
||
p = read_encoded_value_with_base (encoding, base, f->pc_begin,
|
||
&pc_begin);
|
||
read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range);
|
||
|
||
if ((_Unwind_Ptr) pc < pc_begin)
|
||
hi = i;
|
||
else if ((_Unwind_Ptr) pc >= pc_begin + pc_range)
|
||
lo = i + 1;
|
||
else
|
||
return f;
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
static inline const fde *
|
||
binary_search_mixed_encoding_fdes (struct object *ob, void *pc)
|
||
{
|
||
struct fde_vector *vec = ob->u.sort;
|
||
size_t lo, hi;
|
||
|
||
for (lo = 0, hi = vec->count; lo < hi; )
|
||
{
|
||
size_t i = (lo + hi) / 2;
|
||
const fde *f = vec->array[i];
|
||
_Unwind_Ptr pc_begin, pc_range;
|
||
const unsigned char *p;
|
||
int encoding;
|
||
|
||
encoding = get_fde_encoding (f);
|
||
p = read_encoded_value_with_base (encoding,
|
||
base_from_object (encoding, ob),
|
||
f->pc_begin, &pc_begin);
|
||
read_encoded_value_with_base (encoding & 0x0F, 0, p, &pc_range);
|
||
|
||
if ((_Unwind_Ptr) pc < pc_begin)
|
||
hi = i;
|
||
else if ((_Unwind_Ptr) pc >= pc_begin + pc_range)
|
||
lo = i + 1;
|
||
else
|
||
return f;
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
static const fde *
|
||
search_object (struct object* ob, void *pc)
|
||
{
|
||
/* If the data hasn't been sorted, try to do this now. We may have
|
||
more memory available than last time we tried. */
|
||
if (! ob->s.b.sorted)
|
||
{
|
||
init_object (ob);
|
||
|
||
/* Despite the above comment, the normal reason to get here is
|
||
that we've not processed this object before. A quick range
|
||
check is in order. */
|
||
if (pc < ob->pc_begin)
|
||
return NULL;
|
||
}
|
||
|
||
if (ob->s.b.sorted)
|
||
{
|
||
if (ob->s.b.mixed_encoding)
|
||
return binary_search_mixed_encoding_fdes (ob, pc);
|
||
else if (ob->s.b.encoding == DW_EH_PE_absptr)
|
||
return binary_search_unencoded_fdes (ob, pc);
|
||
else
|
||
return binary_search_single_encoding_fdes (ob, pc);
|
||
}
|
||
else
|
||
{
|
||
/* Long slow labourious linear search, cos we've no memory. */
|
||
if (ob->s.b.from_array)
|
||
{
|
||
fde **p;
|
||
for (p = ob->u.array; *p ; p++)
|
||
{
|
||
const fde *f = linear_search_fdes (ob, *p, pc);
|
||
if (f)
|
||
return f;
|
||
}
|
||
return NULL;
|
||
}
|
||
else
|
||
return linear_search_fdes (ob, ob->u.single, pc);
|
||
}
|
||
}
|
||
|
||
const fde *
|
||
_Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
|
||
{
|
||
struct object *ob;
|
||
const fde *f = NULL;
|
||
|
||
init_object_mutex_once ();
|
||
__gthread_mutex_lock (&object_mutex);
|
||
|
||
/* Linear search through the classified objects, to find the one
|
||
containing the pc. Note that pc_begin is sorted descending, and
|
||
we expect objects to be non-overlapping. */
|
||
for (ob = seen_objects; ob; ob = ob->next)
|
||
if (pc >= ob->pc_begin)
|
||
{
|
||
f = search_object (ob, pc);
|
||
if (f)
|
||
goto fini;
|
||
break;
|
||
}
|
||
|
||
/* Classify and search the objects we've not yet processed. */
|
||
while ((ob = unseen_objects))
|
||
{
|
||
struct object **p;
|
||
|
||
unseen_objects = ob->next;
|
||
f = search_object (ob, pc);
|
||
|
||
/* Insert the object into the classified list. */
|
||
for (p = &seen_objects; *p ; p = &(*p)->next)
|
||
if ((*p)->pc_begin < ob->pc_begin)
|
||
break;
|
||
ob->next = *p;
|
||
*p = ob;
|
||
|
||
if (f)
|
||
goto fini;
|
||
}
|
||
|
||
fini:
|
||
__gthread_mutex_unlock (&object_mutex);
|
||
|
||
if (f)
|
||
{
|
||
int encoding;
|
||
|
||
bases->tbase = ob->tbase;
|
||
bases->dbase = ob->dbase;
|
||
|
||
encoding = ob->s.b.encoding;
|
||
if (ob->s.b.mixed_encoding)
|
||
encoding = get_fde_encoding (f);
|
||
read_encoded_value_with_base (encoding, base_from_object (encoding, ob),
|
||
f->pc_begin, (_Unwind_Ptr *)&bases->func);
|
||
}
|
||
|
||
return f;
|
||
}
|