int
dwarf_getlocation_implicit_value (Dwarf_Attribute *attr, const Dwarf_Op *op,
Dwarf_Block *return_block)
{
if (attr == NULL)
return -1;
struct loc_block_s fake = { .addr = (void *) op };
struct loc_block_s **found = tfind (&fake, &attr->cu->locs, loc_compare);
if (unlikely (found == NULL))
{
__libdw_seterrno (DWARF_E_NO_BLOCK);
return -1;
}
return_block->length = (*found)->length;
return_block->data = (*found)->data;
return 0;
}
/* DW_AT_data_member_location can be a constant as well as a loclistptr.
Only data[48] indicate a loclistptr. */
static int
check_constant_offset (Dwarf_Attribute *attr,
Dwarf_Op **llbuf, size_t *listlen)
{
if (attr->code != DW_AT_data_member_location)
return 1;
switch (attr->form)
{
/* Punt for any non-constant form. */
default:
return 1;
case DW_FORM_data1:
case DW_FORM_data2:
case DW_FORM_data4:
case DW_FORM_data8:
case DW_FORM_sdata:
case DW_FORM_udata:
break;
}
/* Check whether we already cached this location. */
struct loc_s fake = { .addr = attr->valp };
struct loc_s **found = tfind (&fake, &attr->cu->locs, loc_compare);
if (found == NULL)
{
Dwarf_Word offset;
if (INTUSE(dwarf_formudata) (attr, &offset) != 0)
return -1;
Dwarf_Op *result = libdw_alloc (attr->cu->dbg,
Dwarf_Op, sizeof (Dwarf_Op), 1);
result->atom = DW_OP_plus_uconst;
result->number = offset;
result->number2 = 0;
result->offset = 0;
/* Insert a record in the search tree so we can find it again later. */
struct loc_s *newp = libdw_alloc (attr->cu->dbg,
struct loc_s, sizeof (struct loc_s),
1);
newp->addr = attr->valp;
newp->loc = result;
newp->nloc = 1;
found = tsearch (newp, &attr->cu->locs, loc_compare);
}
assert ((*found)->nloc == 1);
if (llbuf != NULL)
{
*llbuf = (*found)->loc;
*listlen = 1;
}
return 0;
}
int
internal_function
__libdw_intern_expression (Dwarf *dbg, bool other_byte_order,
unsigned int address_size, unsigned int ref_size,
void **cache, const Dwarf_Block *block,
bool cfap, bool valuep,
Dwarf_Op **llbuf, size_t *listlen, int sec_index)
{
/* Empty location expressions don't have any ops to intern. */
if (block->length == 0)
{
*listlen = 0;
return 0;
}
/* Check whether we already looked at this list. */
struct loc_s fake = { .addr = block->data };
struct loc_s **found = tfind (&fake, cache, loc_compare);
if (found != NULL)
{
/* We already saw it. */
*llbuf = (*found)->loc;
*listlen = (*found)->nloc;
if (valuep)
{
assert (*listlen > 1);
assert ((*llbuf)[*listlen - 1].atom == DW_OP_stack_value);
}
return 0;
}
const unsigned char *data = block->data;
const unsigned char *const end_data = data + block->length;
const struct { bool other_byte_order; } bo = { other_byte_order };
struct loclist *loclist = NULL;
unsigned int n = 0;
/* Stack allocate at most this many locs. */
#define MAX_STACK_LOCS 256
struct loclist stack_locs[MAX_STACK_LOCS];
#define NEW_LOC() ({ struct loclist *ll; \
ll = (likely (n < MAX_STACK_LOCS) \
? &stack_locs[n] \
: malloc (sizeof (struct loclist))); \
if (unlikely (ll == NULL)) \
goto nomem; \
n++; \
ll->next = loclist; \
loclist = ll; \
ll; })
if (cfap)
{
/* Synthesize the operation to push the CFA before the expression. */
struct loclist *newloc = NEW_LOC ();
newloc->atom = DW_OP_call_frame_cfa;
newloc->number = 0;
newloc->number2 = 0;
newloc->offset = -1;
}
/* Decode the opcodes. It is possible in some situations to have a
block of size zero. */
while (data < end_data)
{
struct loclist *newloc;
newloc = NEW_LOC ();
newloc->number = 0;
newloc->number2 = 0;
newloc->offset = data - block->data;
switch ((newloc->atom = *data++))
{
case DW_OP_addr:
/* Address, depends on address size of CU. */
if (dbg == NULL)
{
// XXX relocation?
if (address_size == 4)
{
if (unlikely (data + 4 > end_data))
goto invalid;
else
newloc->number = read_4ubyte_unaligned_inc (&bo, data);
}
else
{
if (unlikely (data + 8 > end_data))
goto invalid;
else
newloc->number = read_8ubyte_unaligned_inc (&bo, data);
}
}
else if (__libdw_read_address_inc (dbg, sec_index, &data,
address_size, &newloc->number))
goto invalid;
break;
case DW_OP_call_ref:
/* DW_FORM_ref_addr, depends on offset size of CU. */
if (dbg == NULL || __libdw_read_offset_inc (dbg, sec_index, &data,
ref_size,
&newloc->number,
IDX_debug_info, 0))
goto invalid;
break;
case DW_OP_deref:
case DW_OP_dup:
case DW_OP_drop:
case DW_OP_over:
case DW_OP_swap:
case DW_OP_rot:
case DW_OP_xderef:
case DW_OP_abs:
case DW_OP_and:
case DW_OP_div:
case DW_OP_minus:
case DW_OP_mod:
case DW_OP_mul:
case DW_OP_neg:
case DW_OP_not:
case DW_OP_or:
case DW_OP_plus:
case DW_OP_shl:
case DW_OP_shr:
case DW_OP_shra:
case DW_OP_xor:
case DW_OP_eq:
case DW_OP_ge:
case DW_OP_gt:
case DW_OP_le:
case DW_OP_lt:
case DW_OP_ne:
case DW_OP_lit0 ... DW_OP_lit31:
case DW_OP_reg0 ... DW_OP_reg31:
case DW_OP_nop:
case DW_OP_push_object_address:
case DW_OP_call_frame_cfa:
case DW_OP_form_tls_address:
case DW_OP_GNU_push_tls_address:
case DW_OP_stack_value:
/* No operand. */
break;
case DW_OP_const1u:
case DW_OP_pick:
case DW_OP_deref_size:
case DW_OP_xderef_size:
if (unlikely (data >= end_data))
{
invalid:
__libdw_seterrno (DWARF_E_INVALID_DWARF);
returnmem:
/* Free any dynamicly allocated loclists, if any. */
while (n > MAX_STACK_LOCS)
{
struct loclist *loc = loclist;
loclist = loc->next;
free (loc);
n--;
}
return -1;
}
newloc->number = *data++;
break;
case DW_OP_const1s:
if (unlikely (data >= end_data))
goto invalid;
newloc->number = *((int8_t *) data);
++data;
break;
case DW_OP_const2u:
if (unlikely (data + 2 > end_data))
goto invalid;
newloc->number = read_2ubyte_unaligned_inc (&bo, data);
break;
case DW_OP_const2s:
case DW_OP_skip:
case DW_OP_bra:
case DW_OP_call2:
if (unlikely (data + 2 > end_data))
goto invalid;
newloc->number = read_2sbyte_unaligned_inc (&bo, data);
break;
case DW_OP_const4u:
if (unlikely (data + 4 > end_data))
goto invalid;
newloc->number = read_4ubyte_unaligned_inc (&bo, data);
break;
case DW_OP_const4s:
case DW_OP_call4:
case DW_OP_GNU_parameter_ref:
if (unlikely (data + 4 > end_data))
goto invalid;
newloc->number = read_4sbyte_unaligned_inc (&bo, data);
break;
case DW_OP_const8u:
if (unlikely (data + 8 > end_data))
goto invalid;
newloc->number = read_8ubyte_unaligned_inc (&bo, data);
break;
case DW_OP_const8s:
if (unlikely (data + 8 > end_data))
goto invalid;
newloc->number = read_8sbyte_unaligned_inc (&bo, data);
break;
case DW_OP_constu:
case DW_OP_plus_uconst:
case DW_OP_regx:
case DW_OP_piece:
case DW_OP_GNU_convert:
case DW_OP_GNU_reinterpret:
get_uleb128 (newloc->number, data, end_data);
break;
case DW_OP_consts:
case DW_OP_breg0 ... DW_OP_breg31:
case DW_OP_fbreg:
get_sleb128 (newloc->number, data, end_data);
break;
case DW_OP_bregx:
get_uleb128 (newloc->number, data, end_data);
if (unlikely (data >= end_data))
goto invalid;
get_sleb128 (newloc->number2, data, end_data);
break;
case DW_OP_bit_piece:
case DW_OP_GNU_regval_type:
get_uleb128 (newloc->number, data, end_data);
if (unlikely (data >= end_data))
goto invalid;
get_uleb128 (newloc->number2, data, end_data);
break;
case DW_OP_implicit_value:
case DW_OP_GNU_entry_value:
/* This cannot be used in a CFI expression. */
if (unlikely (dbg == NULL))
goto invalid;
/* start of block inc. len. */
newloc->number2 = (Dwarf_Word) (uintptr_t) data;
get_uleb128 (newloc->number, data, end_data); /* Block length. */
if (unlikely ((Dwarf_Word) (end_data - data) < newloc->number))
goto invalid;
data += newloc->number; /* Skip the block. */
break;
case DW_OP_GNU_implicit_pointer:
/* DW_FORM_ref_addr, depends on offset size of CU. */
if (dbg == NULL || __libdw_read_offset_inc (dbg, sec_index, &data,
ref_size,
&newloc->number,
IDX_debug_info, 0))
goto invalid;
if (unlikely (data >= end_data))
goto invalid;
get_uleb128 (newloc->number2, data, end_data); /* Byte offset. */
break;
case DW_OP_GNU_deref_type:
if (unlikely (data + 1 >= end_data))
goto invalid;
newloc->number = *data++;
get_uleb128 (newloc->number2, data, end_data);
break;
case DW_OP_GNU_const_type:
{
size_t size;
get_uleb128 (newloc->number, data, end_data);
if (unlikely (data >= end_data))
goto invalid;
/* start of block inc. len. */
newloc->number2 = (Dwarf_Word) (uintptr_t) data;
size = *data++;
if (unlikely ((Dwarf_Word) (end_data - data) < size))
goto invalid;
data += size; /* Skip the block. */
}
break;
default:
goto invalid;
}
}
if (unlikely (n == 0))
{
/* This is not allowed.
It would mean an empty location expression, which we handled
already as a special case above. */
goto invalid;
}
if (valuep)
{
struct loclist *newloc = NEW_LOC ();
newloc->atom = DW_OP_stack_value;
newloc->number = 0;
newloc->number2 = 0;
newloc->offset = data - block->data;
}
/* Allocate the array. */
Dwarf_Op *result;
if (dbg != NULL)
result = libdw_alloc (dbg, Dwarf_Op, sizeof (Dwarf_Op), n);
else
{
result = malloc (sizeof *result * n);
if (result == NULL)
{
nomem:
__libdw_seterrno (DWARF_E_NOMEM);
goto returnmem;
}
}
/* Store the result. */
*llbuf = result;
*listlen = n;
do
{
/* We populate the array from the back since the list is backwards. */
--n;
result[n].atom = loclist->atom;
result[n].number = loclist->number;
result[n].number2 = loclist->number2;
result[n].offset = loclist->offset;
if (result[n].atom == DW_OP_implicit_value)
store_implicit_value (dbg, cache, &result[n]);
struct loclist *loc = loclist;
loclist = loclist->next;
if (unlikely (n + 1 > MAX_STACK_LOCS))
free (loc);
}
while (n > 0);
/* Insert a record in the search tree so that we can find it again later. */
struct loc_s *newp;
if (dbg != NULL)
newp = libdw_alloc (dbg, struct loc_s, sizeof (struct loc_s), 1);
else
{
newp = malloc (sizeof *newp);
if (newp == NULL)
{
free (result);
goto nomem;
}
}
newp->addr = block->data;
newp->loc = result;
newp->nloc = *listlen;
(void) tsearch (newp, cache, loc_compare);
/* We did it. */
return 0;
}
static int
getlocation (struct Dwarf_CU *cu, const Dwarf_Block *block,
Dwarf_Op **llbuf, size_t *listlen, int sec_index)
{
/* Empty location expressions don't have any ops to intern.
Note that synthetic empty_cu doesn't have an associated DWARF dbg. */
if (block->length == 0)
{
*listlen = 0;
return 0;
}
return __libdw_intern_expression (cu->dbg, cu->dbg->other_byte_order,
cu->address_size, (cu->version == 2
? cu->address_size
: cu->offset_size),
&cu->locs, block,
false, false,
llbuf, listlen, sec_index);
}
int
dwarf_getlocation (Dwarf_Attribute *attr, Dwarf_Op **llbuf, size_t *listlen)
{
if (! attr_ok (attr))
return -1;
int result = check_constant_offset (attr, llbuf, listlen);
if (result != 1)
return result;
/* If it has a block form, it's a single location expression. */
Dwarf_Block block;
if (INTUSE(dwarf_formblock) (attr, &block) != 0)
return -1;
return getlocation (attr->cu, &block, llbuf, listlen, cu_sec_idx (attr->cu));
}
static int
attr_base_address (Dwarf_Attribute *attr, Dwarf_Addr *basep)
{
/* Fetch the CU's base address. */
Dwarf_Die cudie = CUDIE (attr->cu);
/* Find the base address of the compilation unit. It will
normally be specified by DW_AT_low_pc. In DWARF-3 draft 4,
the base address could be overridden by DW_AT_entry_pc. It's
been removed, but GCC emits DW_AT_entry_pc and not DW_AT_lowpc
for compilation units with discontinuous ranges. */
Dwarf_Attribute attr_mem;
if (unlikely (INTUSE(dwarf_lowpc) (&cudie, basep) != 0)
&& INTUSE(dwarf_formaddr) (INTUSE(dwarf_attr) (&cudie,
DW_AT_entry_pc,
&attr_mem),
basep) != 0)
{
if (INTUSE(dwarf_errno) () != 0)
return -1;
/* The compiler provided no base address when it should
have. Buggy GCC does this when it used absolute
addresses in the location list and no DW_AT_ranges. */
*basep = 0;
}
return 0;
}
static int
getlocation (struct Dwarf_CU *cu, const Dwarf_Block *block,
Dwarf_Op **llbuf, size_t *listlen)
{
Dwarf *dbg = cu->dbg;
/* Check whether we already looked at this list. */
struct loc_s fake = { .addr = block->data };
struct loc_s **found = tfind (&fake, &cu->locs, loc_compare);
if (found != NULL)
{
/* We already saw it. */
*llbuf = (*found)->loc;
*listlen = (*found)->nloc;
return 0;
}
const unsigned char *data = block->data;
const unsigned char *const end_data = data + block->length;
struct loclist *loclist = NULL;
unsigned int n = 0;
/* Decode the opcodes. It is possible in some situations to have a
block of size zero. */
while (data < end_data)
{
struct loclist *newloc;
newloc = (struct loclist *) alloca (sizeof (struct loclist));
newloc->number = 0;
newloc->number2 = 0;
newloc->offset = data - block->data;
newloc->next = loclist;
loclist = newloc;
++n;
switch ((newloc->atom = *data++))
{
case DW_OP_addr:
/* Address, depends on address size of CU. */
if (cu->address_size == 4)
{
if (unlikely (data + 4 > end_data))
{
invalid:
__libdw_seterrno (DWARF_E_INVALID_DWARF);
return -1;
}
newloc->number = read_4ubyte_unaligned_inc (dbg, data);
}
else
{
if (unlikely (data + 8 > end_data))
goto invalid;
newloc->number = read_8ubyte_unaligned_inc (dbg, data);
}
break;
case DW_OP_deref:
case DW_OP_dup:
case DW_OP_drop:
case DW_OP_over:
case DW_OP_swap:
case DW_OP_rot:
case DW_OP_xderef:
case DW_OP_abs:
case DW_OP_and:
case DW_OP_div:
case DW_OP_minus:
case DW_OP_mod:
case DW_OP_mul:
case DW_OP_neg:
case DW_OP_not:
case DW_OP_or:
case DW_OP_plus:
case DW_OP_shl:
case DW_OP_shr:
case DW_OP_shra:
case DW_OP_xor:
case DW_OP_eq:
case DW_OP_ge:
case DW_OP_gt:
case DW_OP_le:
case DW_OP_lt:
case DW_OP_ne:
case DW_OP_lit0 ... DW_OP_lit31:
case DW_OP_reg0 ... DW_OP_reg31:
case DW_OP_nop:
case DW_OP_push_object_address:
case DW_OP_call_ref:
/* No operand. */
break;
case DW_OP_const1u:
case DW_OP_pick:
case DW_OP_deref_size:
case DW_OP_xderef_size:
if (unlikely (data >= end_data))
goto invalid;
newloc->number = *data++;
break;
case DW_OP_const1s:
if (unlikely (data >= end_data))
goto invalid;
newloc->number = *((int8_t *) data);
++data;
break;
case DW_OP_const2u:
if (unlikely (data + 2 > end_data))
goto invalid;
newloc->number = read_2ubyte_unaligned_inc (dbg, data);
break;
case DW_OP_const2s:
case DW_OP_skip:
case DW_OP_bra:
case DW_OP_call2:
if (unlikely (data + 2 > end_data))
goto invalid;
newloc->number = read_2sbyte_unaligned_inc (dbg, data);
break;
case DW_OP_const4u:
if (unlikely (data + 4 > end_data))
goto invalid;
newloc->number = read_4ubyte_unaligned_inc (dbg, data);
break;
case DW_OP_const4s:
case DW_OP_call4:
if (unlikely (data + 4 > end_data))
goto invalid;
newloc->number = read_4sbyte_unaligned_inc (dbg, data);
break;
case DW_OP_const8u:
if (unlikely (data + 8 > end_data))
goto invalid;
newloc->number = read_8ubyte_unaligned_inc (dbg, data);
break;
case DW_OP_const8s:
if (unlikely (data + 8 > end_data))
goto invalid;
newloc->number = read_8sbyte_unaligned_inc (dbg, data);
break;
case DW_OP_constu:
case DW_OP_plus_uconst:
case DW_OP_regx:
case DW_OP_piece:
/* XXX Check size. */
get_uleb128 (newloc->number, data);
break;
case DW_OP_consts:
case DW_OP_breg0 ... DW_OP_breg31:
case DW_OP_fbreg:
/* XXX Check size. */
get_sleb128 (newloc->number, data);
break;
case DW_OP_bregx:
/* XXX Check size. */
get_uleb128 (newloc->number, data);
get_sleb128 (newloc->number2, data);
break;
default:
goto invalid;
}
}
if (unlikely (n == 0))
{
/* This is not allowed.
XXX Is it? */
goto invalid;
}
/* Allocate the array. */
Dwarf_Op *result = libdw_alloc (dbg, Dwarf_Op, sizeof (Dwarf_Op), n);
/* Store the result. */
*llbuf = result;
*listlen = n;
do
{
/* We populate the array from the back since the list is
backwards. */
--n;
result[n].atom = loclist->atom;
result[n].number = loclist->number;
result[n].number2 = loclist->number2;
result[n].offset = loclist->offset;
loclist = loclist->next;
}
while (n > 0);
/* Insert a record in the search tree so that we can find it again
later. */
struct loc_s *newp = libdw_alloc (dbg, struct loc_s, sizeof (struct loc_s),
1);
newp->addr = block->data;
newp->loc = result;
newp->nloc = *listlen;
(void) tsearch (newp, &cu->locs, loc_compare);
/* We did it. */
return 0;
}
int
dwarf_getlocation (attr, llbuf, listlen)
Dwarf_Attribute *attr;
Dwarf_Op **llbuf;
size_t *listlen;
{
if (! attr_ok (attr))
return -1;
/* If it has a block form, it's a single location expression. */
Dwarf_Block block;
if (INTUSE(dwarf_formblock) (attr, &block) != 0)
return -1;
return getlocation (attr->cu, &block, llbuf, listlen);
}
int
dwarf_getlocation_addr (attr, address, llbufs, listlens, maxlocs)
Dwarf_Attribute *attr;
Dwarf_Addr address;
Dwarf_Op **llbufs;
size_t *listlens;
size_t maxlocs;
{
if (! attr_ok (attr))
return -1;
if (llbufs == NULL)
maxlocs = SIZE_MAX;
/* If it has a block form, it's a single location expression. */
Dwarf_Block block;
if (INTUSE(dwarf_formblock) (attr, &block) == 0)
{
if (maxlocs == 0)
return 0;
if (llbufs != NULL &&
getlocation (attr->cu, &block, &llbufs[0], &listlens[0]) != 0)
return -1;
return listlens[0] == 0 ? 0 : 1;
}
int error = INTUSE(dwarf_errno) ();
if (unlikely (error != DWARF_E_NO_BLOCK))
{
__libdw_seterrno (error);
return -1;
}
/* Must have the form data4 or data8 which act as an offset. */
Dwarf_Word offset;
if (unlikely (INTUSE(dwarf_formudata) (attr, &offset) != 0))
return -1;
const Elf_Data *d = attr->cu->dbg->sectiondata[IDX_debug_loc];
if (unlikely (d == NULL))
{
__libdw_seterrno (DWARF_E_NO_LOCLIST);
return -1;
}
Dwarf_Addr base = (Dwarf_Addr) -1;
unsigned char *readp = d->d_buf + offset;
size_t got = 0;
while (got < maxlocs)
{
if ((unsigned char *) d->d_buf + d->d_size - readp
< attr->cu->address_size * 2)
{
invalid:
__libdw_seterrno (DWARF_E_INVALID_DWARF);
return -1;
}
Dwarf_Addr begin;
Dwarf_Addr end;
if (attr->cu->address_size == 8)
{
begin = read_8ubyte_unaligned_inc (attr->cu->dbg, readp);
end = read_8ubyte_unaligned_inc (attr->cu->dbg, readp);
if (begin == (Elf64_Addr) -1l) /* Base address entry. */
{
base = end;
if (unlikely (base == (Dwarf_Addr) -1))
goto invalid;
continue;
}
}
else
{
begin = read_4ubyte_unaligned_inc (attr->cu->dbg, readp);
end = read_4ubyte_unaligned_inc (attr->cu->dbg, readp);
if (begin == (Elf32_Addr) -1) /* Base address entry. */
{
base = end;
continue;
}
}
if (begin == 0 && end == 0) /* End of list entry. */
break;
if ((unsigned char *) d->d_buf + d->d_size - readp < 2)
goto invalid;
/* We have a location expression. */
block.length = read_2ubyte_unaligned_inc (attr->cu->dbg, readp);
block.data = readp;
if ((unsigned char *) d->d_buf + d->d_size - readp
< (ptrdiff_t) block.length)
goto invalid;
readp += block.length;
if (base == (Dwarf_Addr) -1)
{
/* Fetch the CU's base address. */
Dwarf_Die cudie = CUDIE (attr->cu);
/* Find the base address of the compilation unit. It will
normally be specified by DW_AT_low_pc. In DWARF-3 draft 4,
the base address could be overridden by DW_AT_entry_pc. It's
been removed, but GCC emits DW_AT_entry_pc and not DW_AT_lowpc
for compilation units with discontinuous ranges. */
Dwarf_Attribute attr_mem;
if (unlikely (INTUSE(dwarf_lowpc) (&cudie, &base) != 0)
&& INTUSE(dwarf_formaddr) (INTUSE(dwarf_attr) (&cudie,
DW_AT_entry_pc,
&attr_mem),
&base) != 0)
{
if (INTUSE(dwarf_errno) () != 0)
return -1;
/* The compiler provided no base address when it should
have. Buggy GCC does this when it used absolute
addresses in the location list and no DW_AT_ranges. */
base = 0;
}
}
if (address >= base + begin && address < base + end)
{
/* This one matches the address. */
if (llbufs != NULL
&& unlikely (getlocation (attr->cu, &block,
&llbufs[got], &listlens[got]) != 0))
return -1;
++got;
}
}
return got;
}