freebsd-dev/contrib/gcc/unwind-pe.h
2004-07-28 03:11:36 +00:00

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/* Exception handling and frame unwind runtime interface routines.
Copyright (C) 2001, 2002, 2003, 2004 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.
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 combined
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. */
/* @@@ 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. */
#ifndef GCC_UNWIND_PE_H
#define GCC_UNWIND_PE_H
/* 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
#ifndef NO_SIZE_OF_ENCODED_VALUE
/* 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 ();
}
#endif
#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 |= ((_Unwind_Word)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 |= ((_Unwind_Word)byte & 0x7f) << shift;
shift += 7;
}
while (byte & 0x80);
/* Sign-extend a negative value. */
if (shift < 8 * sizeof(result) && (byte & 0x40) != 0)
result |= -(((_Unwind_Word)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__));
const union unaligned *u = (const 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 *) (_Unwind_Internal_Ptr) (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
#endif /* unwind-pe.h */