bound_minimal_symbol
lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in, struct obj_section *section,
lookup_msym_prefer prefer)
{
int lo;
int hi;
int newobj;
struct objfile *objfile;
struct minimal_symbol *msymbol;
struct minimal_symbol *best_symbol = NULL;
struct objfile *best_objfile = NULL;
struct bound_minimal_symbol result;
if (section == NULL)
{
section = find_pc_section (pc_in);
if (section == NULL)
return {};
}
minimal_symbol_type want_type = msym_prefer_to_msym_type (prefer);
/* We can not require the symbol found to be in section, because
e.g. IRIX 6.5 mdebug relies on this code returning an absolute
symbol - but find_pc_section won't return an absolute section and
hence the code below would skip over absolute symbols. We can
still take advantage of the call to find_pc_section, though - the
object file still must match. In case we have separate debug
files, search both the file and its separate debug file. There's
no telling which one will have the minimal symbols. */
gdb_assert (section != NULL);
for (objfile = section->objfile;
objfile != NULL;
objfile = objfile_separate_debug_iterate (section->objfile, objfile))
{
CORE_ADDR pc = pc_in;
/* If this objfile has a minimal symbol table, go search it using
a binary search. Note that a minimal symbol table always consists
of at least two symbols, a "real" symbol and the terminating
"null symbol". If there are no real symbols, then there is no
minimal symbol table at all. */
if (objfile->per_bfd->minimal_symbol_count > 0)
{
int best_zero_sized = -1;
msymbol = objfile->per_bfd->msymbols;
lo = 0;
hi = objfile->per_bfd->minimal_symbol_count - 1;
/* This code assumes that the minimal symbols are sorted by
ascending address values. If the pc value is greater than or
equal to the first symbol's address, then some symbol in this
minimal symbol table is a suitable candidate for being the
"best" symbol. This includes the last real symbol, for cases
where the pc value is larger than any address in this vector.
By iterating until the address associated with the current
hi index (the endpoint of the test interval) is less than
or equal to the desired pc value, we accomplish two things:
(1) the case where the pc value is larger than any minimal
symbol address is trivially solved, (2) the address associated
with the hi index is always the one we want when the interation
terminates. In essence, we are iterating the test interval
down until the pc value is pushed out of it from the high end.
Warning: this code is trickier than it would appear at first. */
if (frob_address (objfile, &pc)
&& pc >= MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[lo]))
{
while (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]) > pc)
{
/* pc is still strictly less than highest address. */
/* Note "new" will always be >= lo. */
newobj = (lo + hi) / 2;
if ((MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[newobj]) >= pc)
|| (lo == newobj))
{
hi = newobj;
}
else
{
lo = newobj;
}
}
/* If we have multiple symbols at the same address, we want
hi to point to the last one. That way we can find the
right symbol if it has an index greater than hi. */
while (hi < objfile->per_bfd->minimal_symbol_count - 1
&& (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
== MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi + 1])))
hi++;
/* Skip various undesirable symbols. */
while (hi >= 0)
{
/* Skip any absolute symbols. This is apparently
what adb and dbx do, and is needed for the CM-5.
There are two known possible problems: (1) on
ELF, apparently end, edata, etc. are absolute.
Not sure ignoring them here is a big deal, but if
we want to use them, the fix would go in
elfread.c. (2) I think shared library entry
points on the NeXT are absolute. If we want
special handling for this it probably should be
triggered by a special mst_abs_or_lib or some
such. */
if (MSYMBOL_TYPE (&msymbol[hi]) == mst_abs)
{
hi--;
continue;
}
/* If SECTION was specified, skip any symbol from
wrong section. */
if (section
/* Some types of debug info, such as COFF,
don't fill the bfd_section member, so don't
throw away symbols on those platforms. */
&& MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]) != NULL
&& (!matching_obj_sections
(MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi]),
section)))
{
hi--;
continue;
}
/* If we are looking for a trampoline and this is a
text symbol, or the other way around, check the
preceding symbol too. If they are otherwise
identical prefer that one. */
if (hi > 0
&& MSYMBOL_TYPE (&msymbol[hi]) != want_type
&& MSYMBOL_TYPE (&msymbol[hi - 1]) == want_type
&& (MSYMBOL_SIZE (&msymbol[hi])
== MSYMBOL_SIZE (&msymbol[hi - 1]))
&& (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
== MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1]))
&& (MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi])
== MSYMBOL_OBJ_SECTION (objfile, &msymbol[hi - 1])))
{
hi--;
continue;
}
/* If the minimal symbol has a zero size, save it
but keep scanning backwards looking for one with
a non-zero size. A zero size may mean that the
symbol isn't an object or function (e.g. a
label), or it may just mean that the size was not
specified. */
if (MSYMBOL_SIZE (&msymbol[hi]) == 0)
{
if (best_zero_sized == -1)
best_zero_sized = hi;
hi--;
continue;
}
/* If we are past the end of the current symbol, try
the previous symbol if it has a larger overlapping
size. This happens on i686-pc-linux-gnu with glibc;
the nocancel variants of system calls are inside
the cancellable variants, but both have sizes. */
if (hi > 0
&& MSYMBOL_SIZE (&msymbol[hi]) != 0
&& pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
+ MSYMBOL_SIZE (&msymbol[hi]))
&& pc < (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi - 1])
+ MSYMBOL_SIZE (&msymbol[hi - 1])))
{
hi--;
continue;
}
/* Otherwise, this symbol must be as good as we're going
to get. */
break;
}
/* If HI has a zero size, and best_zero_sized is set,
then we had two or more zero-sized symbols; prefer
the first one we found (which may have a higher
address). Also, if we ran off the end, be sure
to back up. */
if (best_zero_sized != -1
&& (hi < 0 || MSYMBOL_SIZE (&msymbol[hi]) == 0))
hi = best_zero_sized;
/* If the minimal symbol has a non-zero size, and this
PC appears to be outside the symbol's contents, then
refuse to use this symbol. If we found a zero-sized
symbol with an address greater than this symbol's,
use that instead. We assume that if symbols have
specified sizes, they do not overlap. */
if (hi >= 0
&& MSYMBOL_SIZE (&msymbol[hi]) != 0
&& pc >= (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
+ MSYMBOL_SIZE (&msymbol[hi])))
{
if (best_zero_sized != -1)
hi = best_zero_sized;
else
/* Go on to the next object file. */
continue;
}
/* The minimal symbol indexed by hi now is the best one in this
objfile's minimal symbol table. See if it is the best one
overall. */
if (hi >= 0
&& ((best_symbol == NULL) ||
(MSYMBOL_VALUE_RAW_ADDRESS (best_symbol) <
MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi]))))
{
best_symbol = &msymbol[hi];
best_objfile = objfile;
}
}
}
}
result.minsym = best_symbol;
result.objfile = best_objfile;
return result;
}
static int
hppa64_hpux_in_solib_call_trampoline (struct gdbarch *gdbarch, CORE_ADDR pc)
{
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
/* PA64 has a completely different stub/trampoline scheme. Is it
better? Maybe. It's certainly harder to determine with any
certainty that we are in a stub because we can not refer to the
unwinders to help.
The heuristic is simple. Try to lookup the current PC value in th
minimal symbol table. If that fails, then assume we are not in a
stub and return.
Then see if the PC value falls within the section bounds for the
section containing the minimal symbol we found in the first
step. If it does, then assume we are not in a stub and return.
Finally peek at the instructions to see if they look like a stub. */
struct bound_minimal_symbol minsym;
asection *sec;
CORE_ADDR addr;
int insn;
minsym = lookup_minimal_symbol_by_pc (pc);
if (! minsym.minsym)
return 0;
sec = MSYMBOL_OBJ_SECTION (minsym.objfile, minsym.minsym)->the_bfd_section;
if (bfd_get_section_vma (sec->owner, sec) <= pc
&& pc < (bfd_get_section_vma (sec->owner, sec)
+ bfd_section_size (sec->owner, sec)))
return 0;
/* We might be in a stub. Peek at the instructions. Stubs are 3
instructions long. */
insn = read_memory_integer (pc, 4, byte_order);
/* Find out where we think we are within the stub. */
if ((insn & 0xffffc00e) == 0x53610000)
addr = pc;
else if ((insn & 0xffffffff) == 0xe820d000)
addr = pc - 4;
else if ((insn & 0xffffc00e) == 0x537b0000)
addr = pc - 8;
else
return 0;
/* Now verify each insn in the range looks like a stub instruction. */
insn = read_memory_integer (addr, 4, byte_order);
if ((insn & 0xffffc00e) != 0x53610000)
return 0;
/* Now verify each insn in the range looks like a stub instruction. */
insn = read_memory_integer (addr + 4, 4, byte_order);
if ((insn & 0xffffffff) != 0xe820d000)
return 0;
/* Now verify each insn in the range looks like a stub instruction. */
insn = read_memory_integer (addr + 8, 4, byte_order);
if ((insn & 0xffffc00e) != 0x537b0000)
return 0;
/* Looks like a stub. */
return 1;
}
