274 lines
6.7 KiB
C++
274 lines
6.7 KiB
C++
/* Exception handling and frame unwind runtime interface routines.
|
||
Copyright (C) 2001, 2002 Free Software Foundation, Inc.
|
||
|
||
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.
|
||
|
||
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. */
|
||
|
||
/* @@@ Really this should be out of line, but this also causes link
|
||
compatibility problems with the base ABI. This is slightly better
|
||
than duplicating code, however. */
|
||
|
||
/* If using C++, references to abort have to be qualified with std::. */
|
||
#if __cplusplus
|
||
#define __gxx_abort std::abort
|
||
#else
|
||
#define __gxx_abort abort
|
||
#endif
|
||
|
||
/* Pointer encodings, from dwarf2.h. */
|
||
#define DW_EH_PE_absptr 0x00
|
||
#define DW_EH_PE_omit 0xff
|
||
|
||
#define DW_EH_PE_uleb128 0x01
|
||
#define DW_EH_PE_udata2 0x02
|
||
#define DW_EH_PE_udata4 0x03
|
||
#define DW_EH_PE_udata8 0x04
|
||
#define DW_EH_PE_sleb128 0x09
|
||
#define DW_EH_PE_sdata2 0x0A
|
||
#define DW_EH_PE_sdata4 0x0B
|
||
#define DW_EH_PE_sdata8 0x0C
|
||
#define DW_EH_PE_signed 0x08
|
||
|
||
#define DW_EH_PE_pcrel 0x10
|
||
#define DW_EH_PE_textrel 0x20
|
||
#define DW_EH_PE_datarel 0x30
|
||
#define DW_EH_PE_funcrel 0x40
|
||
#define DW_EH_PE_aligned 0x50
|
||
|
||
#define DW_EH_PE_indirect 0x80
|
||
|
||
|
||
/* Given an encoding, return the number of bytes the format occupies.
|
||
This is only defined for fixed-size encodings, and so does not
|
||
include leb128. */
|
||
|
||
static unsigned int
|
||
size_of_encoded_value (unsigned char encoding)
|
||
{
|
||
if (encoding == DW_EH_PE_omit)
|
||
return 0;
|
||
|
||
switch (encoding & 0x07)
|
||
{
|
||
case DW_EH_PE_absptr:
|
||
return sizeof (void *);
|
||
case DW_EH_PE_udata2:
|
||
return 2;
|
||
case DW_EH_PE_udata4:
|
||
return 4;
|
||
case DW_EH_PE_udata8:
|
||
return 8;
|
||
}
|
||
__gxx_abort ();
|
||
}
|
||
|
||
#ifndef NO_BASE_OF_ENCODED_VALUE
|
||
|
||
/* Given an encoding and an _Unwind_Context, return the base to which
|
||
the encoding is relative. This base may then be passed to
|
||
read_encoded_value_with_base for use when the _Unwind_Context is
|
||
not available. */
|
||
|
||
static _Unwind_Ptr
|
||
base_of_encoded_value (unsigned char encoding, struct _Unwind_Context *context)
|
||
{
|
||
if (encoding == DW_EH_PE_omit)
|
||
return 0;
|
||
|
||
switch (encoding & 0x70)
|
||
{
|
||
case DW_EH_PE_absptr:
|
||
case DW_EH_PE_pcrel:
|
||
case DW_EH_PE_aligned:
|
||
return 0;
|
||
|
||
case DW_EH_PE_textrel:
|
||
return _Unwind_GetTextRelBase (context);
|
||
case DW_EH_PE_datarel:
|
||
return _Unwind_GetDataRelBase (context);
|
||
case DW_EH_PE_funcrel:
|
||
return _Unwind_GetRegionStart (context);
|
||
}
|
||
__gxx_abort ();
|
||
}
|
||
|
||
#endif
|
||
|
||
/* Read an unsigned leb128 value from P, store the value in VAL, return
|
||
P incremented past the value. We assume that a word is large enough to
|
||
hold any value so encoded; if it is smaller than a pointer on some target,
|
||
pointers should not be leb128 encoded on that target. */
|
||
|
||
static const unsigned char *
|
||
read_uleb128 (const unsigned char *p, _Unwind_Word *val)
|
||
{
|
||
unsigned int shift = 0;
|
||
unsigned char byte;
|
||
_Unwind_Word result;
|
||
|
||
result = 0;
|
||
do
|
||
{
|
||
byte = *p++;
|
||
result |= (byte & 0x7f) << shift;
|
||
shift += 7;
|
||
}
|
||
while (byte & 0x80);
|
||
|
||
*val = result;
|
||
return p;
|
||
}
|
||
|
||
/* Similar, but read a signed leb128 value. */
|
||
|
||
static const unsigned char *
|
||
read_sleb128 (const unsigned char *p, _Unwind_Sword *val)
|
||
{
|
||
unsigned int shift = 0;
|
||
unsigned char byte;
|
||
_Unwind_Word result;
|
||
|
||
result = 0;
|
||
do
|
||
{
|
||
byte = *p++;
|
||
result |= (byte & 0x7f) << shift;
|
||
shift += 7;
|
||
}
|
||
while (byte & 0x80);
|
||
|
||
/* Sign-extend a negative value. */
|
||
if (shift < 8 * sizeof(result) && (byte & 0x40) != 0)
|
||
result |= -(1L << shift);
|
||
|
||
*val = (_Unwind_Sword) result;
|
||
return p;
|
||
}
|
||
|
||
/* Load an encoded value from memory at P. The value is returned in VAL;
|
||
The function returns P incremented past the value. BASE is as given
|
||
by base_of_encoded_value for this encoding in the appropriate context. */
|
||
|
||
static const unsigned char *
|
||
read_encoded_value_with_base (unsigned char encoding, _Unwind_Ptr base,
|
||
const unsigned char *p, _Unwind_Ptr *val)
|
||
{
|
||
union unaligned
|
||
{
|
||
void *ptr;
|
||
unsigned u2 __attribute__ ((mode (HI)));
|
||
unsigned u4 __attribute__ ((mode (SI)));
|
||
unsigned u8 __attribute__ ((mode (DI)));
|
||
signed s2 __attribute__ ((mode (HI)));
|
||
signed s4 __attribute__ ((mode (SI)));
|
||
signed s8 __attribute__ ((mode (DI)));
|
||
} __attribute__((__packed__));
|
||
|
||
union unaligned *u = (union unaligned *) p;
|
||
_Unwind_Internal_Ptr result;
|
||
|
||
if (encoding == DW_EH_PE_aligned)
|
||
{
|
||
_Unwind_Internal_Ptr a = (_Unwind_Internal_Ptr) p;
|
||
a = (a + sizeof (void *) - 1) & - sizeof(void *);
|
||
result = *(_Unwind_Internal_Ptr *) a;
|
||
p = (const unsigned char *) (a + sizeof (void *));
|
||
}
|
||
else
|
||
{
|
||
switch (encoding & 0x0f)
|
||
{
|
||
case DW_EH_PE_absptr:
|
||
result = (_Unwind_Internal_Ptr) u->ptr;
|
||
p += sizeof (void *);
|
||
break;
|
||
|
||
case DW_EH_PE_uleb128:
|
||
{
|
||
_Unwind_Word tmp;
|
||
p = read_uleb128 (p, &tmp);
|
||
result = (_Unwind_Internal_Ptr) tmp;
|
||
}
|
||
break;
|
||
|
||
case DW_EH_PE_sleb128:
|
||
{
|
||
_Unwind_Sword tmp;
|
||
p = read_sleb128 (p, &tmp);
|
||
result = (_Unwind_Internal_Ptr) tmp;
|
||
}
|
||
break;
|
||
|
||
case DW_EH_PE_udata2:
|
||
result = u->u2;
|
||
p += 2;
|
||
break;
|
||
case DW_EH_PE_udata4:
|
||
result = u->u4;
|
||
p += 4;
|
||
break;
|
||
case DW_EH_PE_udata8:
|
||
result = u->u8;
|
||
p += 8;
|
||
break;
|
||
|
||
case DW_EH_PE_sdata2:
|
||
result = u->s2;
|
||
p += 2;
|
||
break;
|
||
case DW_EH_PE_sdata4:
|
||
result = u->s4;
|
||
p += 4;
|
||
break;
|
||
case DW_EH_PE_sdata8:
|
||
result = u->s8;
|
||
p += 8;
|
||
break;
|
||
|
||
default:
|
||
__gxx_abort ();
|
||
}
|
||
|
||
if (result != 0)
|
||
{
|
||
result += ((encoding & 0x70) == DW_EH_PE_pcrel
|
||
? (_Unwind_Internal_Ptr) u : base);
|
||
if (encoding & DW_EH_PE_indirect)
|
||
result = *(_Unwind_Internal_Ptr *) result;
|
||
}
|
||
}
|
||
|
||
*val = result;
|
||
return p;
|
||
}
|
||
|
||
#ifndef NO_BASE_OF_ENCODED_VALUE
|
||
|
||
/* Like read_encoded_value_with_base, but get the base from the context
|
||
rather than providing it directly. */
|
||
|
||
static inline const unsigned char *
|
||
read_encoded_value (struct _Unwind_Context *context, unsigned char encoding,
|
||
const unsigned char *p, _Unwind_Ptr *val)
|
||
{
|
||
return read_encoded_value_with_base (encoding,
|
||
base_of_encoded_value (encoding, context),
|
||
p, val);
|
||
}
|
||
|
||
#endif
|