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Author SHA1 Message Date
Nick Alcock
688d28f621 libctf, next: introduce new class of easier-to-use iterators
The libctf machinery currently only provides one way to iterate over its
data structures: ctf_*_iter functions that take a callback and an arg
and repeatedly call it.

This *works*, but if you are doing a lot of iteration it is really quite
inconvenient: you have to package up your local variables into
structures over and over again and spawn lots of little functions even
if it would be clearer in a single run of code.  Look at ctf-string.c
for an extreme example of how unreadable this can get, with
three-line-long functions proliferating wildly.

The deduplicator takes this to the Nth level. It iterates over a whole
bunch of things: if we'd had to use _iter-class iterators for all of
them there would be twenty additional functions in the deduplicator
alone, for no other reason than that the iterator API requires it.

Let's do something better. strtok_r gives us half the design: generators
in a number of other languages give us the other half.

The *_next API allows you to iterate over CTF-like entities in a single
function using a normal while loop. e.g. here we are iterating over all
the types in a dict:

ctf_next_t *i = NULL;
int *hidden;
ctf_id_t id;

while ((id = ctf_type_next (fp, &i, &hidden, 1)) != CTF_ERR)
  {
    /* do something with 'hidden' and 'id' */
  }
if (ctf_errno (fp) != ECTF_NEXT_END)
    /* iteration error */

Here we are walking through the members of a struct with CTF ID
'struct_type':

ctf_next_t *i = NULL;
ssize_t offset;
const char *name;
ctf_id_t membtype;

while ((offset = ctf_member_next (fp, struct_type, &i, &name,
                                  &membtype)) >= 0
  {
    /* do something with offset, name, and membtype */
  }
if (ctf_errno (fp) != ECTF_NEXT_END)
    /* iteration error */

Like every other while loop, this means you have access to all the local
variables outside the loop while inside it, with no need to tiresomely
package things up in structures, move the body of the loop into a
separate function, etc, as you would with an iterator taking a callback.

ctf_*_next allocates 'i' for you on first entry (when it must be NULL),
and frees and NULLs it and returns a _next-dependent flag value when the
iteration is over: the fp errno is set to ECTF_NEXT_END when the
iteartion ends normally.  If you want to exit early, call
ctf_next_destroy on the iterator.  You can copy iterators using
ctf_next_copy, which copies their current iteration position so you can
remember loop positions and go back to them later (or ctf_next_destroy
them if you don't need them after all).

Each _next function returns an always-likely-to-be-useful property of
the thing being iterated over, and takes pointers to parameters for the
others: with very few exceptions all those parameters can be NULLs if
you're not interested in them, so e.g. you can iterate over only the
offsets of members of a structure this way:

while ((offset = ctf_member_next (fp, struct_id, &i, NULL, NULL)) >= 0)

If you pass an iterator in use by one iteration function to another one,
you get the new error ECTF_NEXT_WRONGFUN back; if you try to change
ctf_file_t in mid-iteration, you get ECTF_NEXT_WRONGFP back.

Internally the ctf_next_t remembers the iteration function in use,
various sizes and increments useful for almost all iterations, then
uses unions to overlap the actual entities being iterated over to keep
ctf_next_t size down.

Iterators available in the public API so far (all tested in actual use
in the deduplicator):

/* Iterate over the members of a STRUCT or UNION, returning each member's
   offset and optionally name and member type in turn.  On end-of-iteration,
   returns -1.  */
ssize_t
ctf_member_next (ctf_file_t *fp, ctf_id_t type, ctf_next_t **it,
                 const char **name, ctf_id_t *membtype);

/* Iterate over the members of an enum TYPE, returning each enumerand's
   NAME or NULL at end of iteration or error, and optionally passing
   back the enumerand's integer VALue.  */
const char *
ctf_enum_next (ctf_file_t *fp, ctf_id_t type, ctf_next_t **it,
              int *val);

/* Iterate over every type in the given CTF container (not including
   parents), optionally including non-user-visible types, returning
   each type ID and optionally the hidden flag in turn. Returns CTF_ERR
   on end of iteration or error.  */
ctf_id_t
ctf_type_next (ctf_file_t *fp, ctf_next_t **it, int *flag,
               int want_hidden);

/* Iterate over every variable in the given CTF container, in arbitrary
   order, returning the name and type of each variable in turn.  The
   NAME argument is not optional.  Returns CTF_ERR on end of iteration
   or error.  */
ctf_id_t
ctf_variable_next (ctf_file_t *fp, ctf_next_t **it, const char **name);

/* Iterate over all CTF files in an archive, returning each dict in turn as a
   ctf_file_t, and NULL on error or end of iteration.  It is the caller's
   responsibility to close it.  Parent dicts may be skipped.  Regardless of
   whether they are skipped or not, the caller must ctf_import the parent if
   need be.  */
ctf_file_t *
ctf_archive_next (const ctf_archive_t *wrapper, ctf_next_t **it,
                  const char **name, int skip_parent, int *errp);

ctf_label_next is prototyped but not implemented yet.

include/
	* ctf-api.h (ECTF_NEXT_END): New error.
	(ECTF_NEXT_WRONGFUN): Likewise.
	(ECTF_NEXT_WRONGFP): Likewise.
	(ECTF_NERR): Adjust.
	(ctf_next_t): New.
	(ctf_next_create): New prototype.
	(ctf_next_destroy): Likewise.
	(ctf_next_copy): Likewise.
	(ctf_member_next): Likewise.
	(ctf_enum_next): Likewise.
	(ctf_type_next): Likewise.
	(ctf_label_next): Likewise.
	(ctf_variable_next): Likewise.

libctf/
	* ctf-impl.h (ctf_next): New.
	(ctf_get_dict): New prototype.
	* ctf-lookup.c (ctf_get_dict): New, split out of...
	(ctf_lookup_by_id): ... here.
	* ctf-util.c (ctf_next_create): New.
	(ctf_next_destroy): New.
	(ctf_next_copy): New.
	* ctf-types.c (includes): Add <assert.h>.
	(ctf_member_next): New.
	(ctf_enum_next): New.
	(ctf_type_iter): Document the lack of iteration over parent
	types.
	(ctf_type_next): New.
	(ctf_variable_next): New.
	* ctf-archive.c (ctf_archive_next): New.
	* libctf.ver: Add new public functions.
2020-07-22 17:57:50 +01:00
Nick Alcock
2399827bfa libctf: add ctf_ref
This allows you to bump the refcount on a ctf_file_t, so that you can
smuggle it out of iterators which open and close the ctf_file_t for you
around the loop body (like ctf_archive_iter).

You still can't use this to preserve a ctf_file_t for longer than the
lifetime of its containing entity (e.g. ctf_archive).

include/
	* ctf-api.h (ctf_ref): New.
libctf/
	* libctf.ver (ctf_ref): New.
	* ctf-open.c (ctf_ref): Implement it.
2020-07-22 17:57:49 +01:00
Nick Alcock
9850ce4d7b libctf: add ctf_forwardable_kind
The internals of the deduplicator want to know if something is a type
that can have a forward to it fairly often, often enough that inlining
it brings a noticeable performance gain.  Convert the one place in
libctf that can already benefit, even though it doesn't bring any sort
of performance gain there.

libctf/
	* ctf-inlines.h (ctf_forwardable_kind): New.
	* ctf-create.c (ctf_add_forward): Use it.
2020-07-22 17:57:48 +01:00
Nick Alcock
2c9ca36be1 libctf: move existing inlines into ctf-inlines.h
Just housekeeping.

libctf/
	* ctf-impl.h (ctf_get_ctt_size): Move definition from here...
	* ctf-inlines.h (ctf_get_ctt_size): ... to here.
2020-07-22 17:57:46 +01:00
Nick Alcock
7764824138 libctf, hash: introduce the ctf_dynset
There are many places in the deduplicator which use hashtables as tiny
sets: keys with no value (and usually, but not always, no freeing
function) often with only one or a few members.  For each of these, even
after the last change to not store the freeing functions, we are storing
a little malloced block for each item just to track the key/value pair,
and a little malloced block for the hash table itself just to track the
freeing function because we can't use libiberty hashtab's freeing
function because we are using that to free the little malloced per-item
block.

If we only have a key, we don't need any of that: we can ditch the
per-malloced block because we don't have a value, and we can ditch the
per-hashtab structure because we don't need to independently track the
freeing functions since libiberty hashtab is doing it for us.  That
means we don't need an owner field in the (now nonexistent) item block
either.

Roughly speaking, this datatype saves about 25% in time and 20% in peak
memory usage for normal links, even fairly big ones.  So this might seem
redundant, but it's really worth it.

Instead of a _lookup function, a dynset has two distinct functions:
ctf_dynset_exists, which returns true or false and an optional pointer
to the set member, and ctf_dynhash_lookup_any, which is used if all
members of the set are expected to be equivalent and we just want *any*
member and we don't care which one.

There is no iterator in this set of functions, not because we don't
iterate over dynset members -- we do, a lot -- but because the iterator
here is a member of an entirely new family of much more convenient
iteration functions, introduced in the next commit.

libctf/
	* ctf-hash.c (ctf_dynset_eq_string): New.
	(ctf_dynset_create): New.
	(DYNSET_EMPTY_ENTRY_REPLACEMENT): New.
	(DYNSET_DELETED_ENTRY_REPLACEMENT): New.
	(key_to_internal): New.
	(internal_to_key): New.
	(ctf_dynset_insert): New.
	(ctf_dynset_remove): New.
	(ctf_dynset_destroy): New.
	(ctf_dynset_lookup): New.
	(ctf_dynset_exists): New.
	(ctf_dynset_lookup_any): New.
	(ctf_hash_insert_type): Coding style.
	(ctf_hash_define_type): Likewise.

	* ctf-impl.h (ctf_dynset_t): New.
	(ctf_dynset_eq_string): New.
	(ctf_dynset_create): New.
	(ctf_dynset_insert): New.
	(ctf_dynset_remove): New.
	(ctf_dynset_destroy): New.
	(ctf_dynset_lookup): New.
	(ctf_dynset_exists): New.
	(ctf_dynset_lookup_any): New.
	* ctf-inlines.h (ctf_dynset_cinsert): New.
2020-07-22 17:57:45 +01:00
Nick Alcock
a49c6c6a65 libctf, hash: save per-item space when no key/item freeing function
The libctf dynhash hashtab abstraction supports per-hashtab arbitrary
key/item freeing functions -- but it also has a constant slot type that
holds both key and value requested by the user, so it needs to use its
own freeing function to free that -- and it has nowhere to store the
freeing functions the caller requested.

So it copies them into every hash item, bloating every slot, even though
all items in a given hash table must have the same key and value freeing
functions.

So point back to the owner using a back-pointer, but don't even spend
space in the item or the hashtab allocating those freeing functions
unless necessary: if none are needed, we can simply arrange to not pass
in ctf_dynhash_item_free as a del_f to hashtab_create_alloc, and none of
those fields will ever be accessed.

The only downside is that this makes the code sensitive to the order of
fields in the ctf_helem_t and ctf_hashtab_t: but the deduplicator
allocates so many hash tables that doing this alone cuts memory usage
during deduplication by about 10%.  (libiberty hashtab itself has a lot
of per-hashtab bloat: in the future we might trim that down, or make a
trimmer version.)

libctf/
	* ctf-hash.c (ctf_helem_t) <key_free>: Remove.
	<value_free>: Likewise.
	<owner>: New.
	(ctf_dynhash_item_free): Indirect through the owner.
	(ctf_dynhash_create): Only pass in ctf_dynhash_item_free and
	allocate space for the key_free and value_free fields fields
	if necessary.
	(ctf_hashtab_insert): Likewise.  Fix OOM errno value.
	(ctf_dynhash_insert): Only access ctf_hashtab's key_free and
	value_free if they will exist.  Set the slot's owner, but only
	if it exists.
	(ctf_dynhash_remove): Adjust.
2020-07-22 17:57:44 +01:00
Nick Alcock
5ceee3dba3 libctf, hash: improve insertion of existing keys into dynhashes
Right now, if you insert a key/value pair into a dynhash, the old slot's
key is freed and the new one always assigned.  This seemed sane to me
when I wrote it, but I got it wrong time and time again.  It's much
less confusing to free the key passed in: if a key-freeing function
was passed, you are asserting that the dynhash owns the key in any
case, so if you pass in a key it is always buggy to assume it sticks
around.  Freeing the old key means that you can't even safely look up a
key from out of a dynhash and hold on to it, because some other matching
key might force it to be freed at any time.

In the new model, you can always get a key out of a dynhash with
ctf_dynhash_lookup_kv and hang on to it until the kv-pair is actually
deleted from the dynhash.  In the old model the pointer to the key might
be freed at any time if a matching key was inserted.

libctf/
	* ctf-hash.c (ctf_hashtab_insert): Free the key passed in if
	there is a key-freeing function and the key already exists.
2020-07-22 17:57:43 +01:00
Nick Alcock
809f6eb332 libctf: add new dynhash functions
Future commits will use these.

ctf_dynhash_elements: count elements in a dynhash
ctf_dynhash_lookup_kv: look up and return pointers to the original key
                       and value in a dynhash (the only way of getting
                       a reference to the original key)
ctf_dynhash_iter_find: iterate until an item is found, then return its
                       key
ctf_dynhash_cinsert: insert a const key / value into a dynhash (a thim
                     wrapper in a new header dedicated to inline
                     functions).

As with the rest of ctf_dynhash, this is not public API.  No impact
on existing callers is expected.

libctf/
	* ctf-inlines.h: New file.
	* ctf-impl.h: Include it.
	(ctf_hash_iter_find_f): New typedef.
	(ctf_dynhash_elements): New.
	(ctf_dynhash_lookup_kv): New.
	(ctf_dynhash_iter_find): New.
	* ctf-hash.c (ctf_dynhash_lookup_kv): New.
	(ctf_traverse_find_cb_arg_t): New.
	(ctf_hashtab_traverse_find): New.
	(ctf_dynhash_iter_find): New.
	(ctf_dynhash_elements): New.
2020-07-22 17:57:41 +01:00
Nick Alcock
469e75b621 libctf: fix __extension__ with non-GNU C compilers
We forgot to #define __extension__ to nothing in this case.

libctf/
	* ctf-impl.h [!__GNUC__] (__extension__): Define to nothing.
2020-07-22 17:57:40 +01:00
Nick Alcock
9c23dfa5aa libctf: add ctf_archive_count
Another count that was otherwise unavailable without doing expensive
operations.

include/
	* ctf-api.h (ctf_archive_count): New.

libctf/
	* ctf-archive.c (ctf_archive_count): New.
	* libctf.ver: New public function.
2020-07-22 17:57:39 +01:00
Nick Alcock
e0325e2ced libctf: add ctf_member_count
This returns the number of members in a struct or union, or the number
of enumerations in an enum.  (This was only available before now by
iterating across every member, but it can be returned much faster than
that.)

include/
	* ctf-api.h (ctf_member_count): New.

libctf/
	* ctf-types.c (ctf_member_count): New.
	* libctf.ver: New public function.
2020-07-22 17:57:38 +01:00
Nick Alcock
9b15cbb789 libctf: add ctf_type_kind_forwarded
This is just like ctf_type_kind, except that forwards get the
type of the thing being pointed to rather than CTF_K_FORWARD.

include/
	* ctf-api.h (ctf_type_kind_forwarded): New.
libctf/
	* ctf-types.c (ctf_type_kind_forwarded): New.
2020-07-22 17:57:37 +01:00
Nick Alcock
01d9317436 libctf: add ctf_type_name_raw
We already have a function ctf_type_aname_raw, which returns the raw
name of a type with no decoration for structures or arrays or anything
like that: just the underlying name of whatever it is that's being
ultimately pointed at.

But this can be inconvenient to use, becauswe it always allocates new
storage for the string and copies it in, so it can potentially fail.
Add ctf_type_name_raw, which just returns the string directly out of
libctf's guts: it will live until the ctf_file_t is closed (if we later
gain the ability to remove types from writable dicts, it will live as
long as the type lives).

Reimplement ctf_type_aname_raw in terms of it.

include/
	* ctf-api.c (ctf_type_name_raw): New.

libctf/
	* ctf-types.c (ctf_type_name_raw): New.
	(ctf_type_aname_raw): Reimplement accordingly.
2020-07-22 17:57:36 +01:00
Nick Alcock
5ec7465fec libctf: having debugging enabled is unlikely
The deduplicator can emit enormous amounts of debugging output,
so much so that a later commit will introduce a new configure flag
that configures most of it out (and configures it out by default).

It became clear that when this configure flag is on, but debugging is
not enabled via the LIBCTF_DEBUG environment variable, up to 10% of
runtime can be spent on branch mispredictions checking the _libctf_debug
variable.  Mark it unlikely to be set (when it is set, performance is
likely to be the least of your concerns).

libctf/
	* ctf-subr.c (ctf_dprintf): _libctf_debug is unlikely to be set.
2020-07-22 17:57:34 +01:00
Nick Alcock
601e455b75 libctf, archive: stop ctf_arc_bufopen triggering crazy unmaps
The archive machinery mmap()s its archives when possible: so it arranges
to do appropriately-sized unmaps by recording the unmap length in the
ctfa_magic value and unmapping that.

This brilliant (horrible) trick works less well when ctf_arc_bufopen is
called with an existing buffer (which might be a readonly mapping).
ctf_arc_bufopen always returns a ctf_archive_t wrapper, so record in
there the necessity to not unmap anything when a bufopen'ed archive is
closed again.

libctf/
	* ctf-impl.h (struct ctf_archive_internal)
	<ctfi_unmap_on_close>: New.
	(ctf_new_archive_internal): Adjust.
	* ctf-archive.c (ctf_new_archive_internal): Likewise.
	Initialize ctfi_unmap_on_close.  Adjust error path.
	(ctf_arc_bufopen): Adjust ctf_new_archive_internal call
	(unmap_on_close is 0).
	(ctf_arc_close): Only unmap if ctfi_unmap_on_close.
	* ctf-open-bfd.c (ctf_fdopen): Adjust.
2020-07-22 17:57:33 +01:00
Nick Alcock
96e3ec2966 libctf, types: ints, floats and typedefs with no name are invalid
Report them as such, rather than letting ctf_decl_sprintf wrongly
conclude that the printing of zero characters means we are out of
memory.

libctf/
	* ctf-types.c (ctf_type_aname): Return ECTF_CORRUPT if
	ints, floats or typedefs have no name.  Fix comment typo.
2020-07-22 17:57:32 +01:00
Nick Alcock
502e838ed9 libctf, types: support slices of anything terminating in an int
It is perfectly valid C to say e.g.

typedef u64 int;
struct foo_t
  {
    const volatile u64 wibble:2;
  };

i.e. bitfields have to be integral types, but they can be cv-qualified
integral types or typedefs of same, etc.

This is easy to fix: do a ctf_type_resolve_unsliced() at creation time
to ensure the ultimate type is integral, and ctf_type_resolve() at
lookup time so that if you somehow have e.g. a slice of a typedef of a
slice of a cv-qualified int, we pull the encoding that the topmost slice
is based on out of the subsidiary slice (and then modify it), not out of
the underlying int.  (This last bit is rather academic right now, since
all slices override exactly the same properties of the underlying type,
but it's still the right thing to do.)

libctf/
	* ctf-create.c (ctf_add_slice): Support slices of any kind that
	resolves to an integral type.
	* ctf-types.c (ctf_type_encoding): Resolve the type before
	fishing its encoding out.
2020-07-22 17:57:31 +01:00
Nick Alcock
dd987f0043 libctf, create: empty dicts are dirty to start with
Without this, an empty dict that is written out immediately never gets
any content at all: even the header is left empty.

libctf/
	* ctf-create.c (ctf_create): Mark dirty.
2020-07-22 17:57:29 +01:00
Nick Alcock
f47ca31135 libctf, create: fix addition of anonymous struct/union members
A Solaris-era bug causes us to check the offsets of types with no names
against the first such type when ctf_add_type()ing members to a struct
or union.  Members with no names (i.e. anonymous struct/union members)
can appear as many times as you like in a struct/union, so this check
should be skipped in this case.

libctf/
	* ctf-create.c (membcmp)  Skip nameless members.
2020-07-22 17:57:28 +01:00
Nick Alcock
ab769488e7 libctf, create: member names of "" and NULL should be the same
This matters for the case of unnamed bitfields, whose names are the null
string.  These are special in that they are the only members whose
"names" are allowed to be duplicated in a single struct, but we were
only handling this for the case where name == NULL.  Translate "" to
NULL to help callers.

libctf/
	* ctf-create.c (ctf_add_member_offset): Support names of ""
	as if they were the null pointer.
2020-07-22 17:57:27 +01:00
Nick Alcock
2484ca436a libctf, open: drop unnecessary historical wart around forwards
When opening, we consider a forward with a kind above the maximum
allowable set of kinds and a forward of kind CTF_K_UNKNOWN to be a
forward to a struct.  Whatever CTF version it was that produced
forwards with no associated kind, it predates anything we can read:
remove this wart.

libctf/
	* ctf-open.c (init_types): Remove typeless CTF_K_FORWARD
	special-casing.
2020-07-22 17:57:26 +01:00
Nick Alcock
437061996d libctf, types: allow ctf_type_reference of dynamic slices
One spot was missed when we rejigged ctf_update into ctf_serialize and
allowed all operations on dynamic containers: ctf_type_reference of
slices.  A dynamic slice's vlen state is stored in the dtu_slice member,
so fetch it from there.

libctf/
	* ctf-types.c (ctf_type_reference): Add support for dynamic slices.
2020-07-22 17:57:24 +01:00
Nick Alcock
9943fa3a73 libctf, create: add explicit casts for variables' and slices' types
This is technically unnecessary -- the compiler is quite capable of
doing the range reduction for us -- but it does mean that all
assignments of a ctf_id_t to its final uint32_t representation now have
appropriate explicit casts.

libctf/
	* ctf-create.c (ctf_serialize): Add cast.
	(ctf_add_slice): Likewise.
2020-07-22 17:57:23 +01:00
Nick Alcock
afd78bd6f0 libctf, create: do not corrupt function types' arglists at insertion time
ctf_add_function assumes that function types' arglists are of type
ctf_id_t.  Since they are CTF IDs, they are 32 bits wide, a uint32_t:
unfortunately ctf_id_t is a forward-compatible user-facing 64 bits wide,
and should never ever reach the CTF storage level.

All the CTF code other than ctf_add_function correctly assumes that
function arglists outside dynamic containers are 32 bits wide, so the
serialization machinery ends up cutting off half the arglist, corrupting
all args but the first (a good sign is a bunch of args of ID 0, the
unimplemented type, popping up).

Fix this by copying the arglist into place item by item, casting it
properly, at the same time as we validate the arg types.  Fix the type
of the dtu_argv in the dynamic container and drop the now-unnecessary
cast in the serializer.

libctf/
	* ctf-impl.h (ctf_dtdef_t) <dtu_argv>: Fix type.
	* ctf-create.c (ctf_add_function): Check for unimplemented type
	and populate at the same time.  Populate one-by-one, not via
	memcpy.
	(ctf_serialize): Remove unnecessary cast.
	* ctf-types.c (ctf_func_type_info): Likewise.
	(ctf_func_type_args): Likewise.  Fix comment typo.
2020-07-22 17:57:22 +01:00
Nick Alcock
2361f1c859 libctf, create: support addition of references to the unimplemented type
The deduplicating linker adds types from the linker inputs to the output
via the same API everyone else does, so it's important that we can emit
everything that the compiler wants us to.  Unfortunately, the compiler
may represent the unimplemented type (used for compiler constructs that
CTF cannot currently encode) as type zero or as a type of kind
CTF_K_UNKNOWN, and we don't allow the addition of types that cite the
former.

Adding this support adds a tiny bit of extra complexity: additions of
structure members immediately following a member of the unimplemented
type must be via ctf_add_member_offset or ctf_add_member_encoded, since
we have no idea how big members of the unimplemented type are.
(Attempts to do otherwise return -ECTF_NONREPRESENTABLE, like other
attempts to do forbidden things with the unimplemented type.)

Even slices of the unimplemented type are permitted: this is the only
case in which you can slice a type that terminates in a non-integral
type, on the grounds that it was likely integral in the source code,
it's just that we can't represent that sort of integral type properly
yet.

libctf/
	* ctf-create.c (ctf_add_reftype): Support refs to type zero.
	(ctf_add_array): Support array contents of type zero.
	(ctf_add_function): Support arguments and return types of
	type zero.
	(ctf_add_typedef): Support typedefs to type zero.
	(ctf_add_member_offset): Support members of type zero,
	unless added at unspecified (naturally-aligned) offset.
2020-07-22 17:57:21 +01:00
Nick Alcock
7eea9d3bdb libctf: restructure error handling to reduce relocations
Jose Marchesi noted that the traditional-Unix error array in ctf-error.c
introduces one reloc per error to initialize the array: 58 so far.  We
can reduce this to zero using an array of carefully-sized individual
members which is used to construct a string table, that is then
referenced by the lookup functions: but doing this automatically is a
pain.

Bruno Haible wrote suitable code years ago: I got permission to reuse it
(Bruno says "... which I hereby put in the public domain"); I modified
it a tiny bit (similarly to what Ulrich Drepper did in the dsohowto
text, but I redid it from scratch), commented it up a bit, and shifted
the error table into that form, migrating it into the new file
ctf-error.h.

This has the advantage that it spotted both typos in the text of the
errors in the comments in ctf-api.h and typos in the error defines in
the comments in ctf-error.c, and places where the two were simply not
in sync.  All are now fixed.

One new constant exists in ctf-api.h: CTF_NERR, since the old method of
working out the number of errors in ctf-error.c was no longer usable,
and it seems that the number of CTF errors is something users might
reasonably want as well.  It should be pretty easy to keep up to date as
new errors are introduced.

include/
	* ctf-api.h (ECTF_*): Improve comments.
	(ECTF_NERR): New.

libctf/
	* ctf-error.c: Include <stddef.h>, for offsetof.
	(_ctf_errlist): Migrate to...
	(_ctf_errlist_t): ... this.
	(_ctf_erridx): New, indexes into _ctf_errlist_t.
	(_ctf_nerr): Remove.
	(ctf_errmsg): Adjust accordingly.
	* Makefile.am (BUILT_SOURCES): Note...
	(ctf-error.h): ... this new rule.
	* Makefile.in: Regenerate.
	* mkerrors.sed: New, process ctf-api.h to generate ctf-error.h.
	* .gitignore: New, ignore ctf-error.h.
2020-07-22 17:57:20 +01:00
Nick Alcock
b64751cf0b include, libctf: typo fixes
include/
	* ctf-api.h: Fix typos in comments.
libctf/
	* ctf-impl.h: Fix typos in comments.
2020-07-22 17:57:19 +01:00
Reuben Thomas
c9fe1b583c Correct an error in the remote protocol specification
The list of commands that a stub must implement was wrong.

gdb/ChangeLog:
2020-07-22  Reuben Thomas  <rrt@sc3d.org>

	* gdb.texinfo (Remote Protocol, Overview): Correct the description
	of which remote protocol commands are mandatory for a stub to
	implement.
2020-07-22 16:15:29 +01:00
Andrew Burgess
a67a1c41fe gdb/python: Use reference not pointer in py-registers.c
Pedro's review comments arrived after I'd already committed this
change:

  commit f7306dac19
  Date:   Tue Jul 7 15:00:30 2020 +0100

      gdb/python: Reuse gdb.RegisterDescriptor objects where possible

See:

  https://sourceware.org/pipermail/gdb-patches/2020-July/170726.html

There should be no user visible changes after this commit.

gdb/ChangeLog:

	* python/py-registers.c (gdbpy_register_object_data_init): Remove
	redundant local variable.
	(gdbpy_get_register_descriptor): Extract descriptor vector as a
	reference, not pointer, update code accordingly.
2020-07-22 16:09:16 +01:00
Nick Clifton
df16e041de Fix problems in CTF handling code exposed by the Coverity static analysis tool.
readelf	* readelf.c (parse_args): Silence potential warnings about a
	memory resource leak when allocating space for ctf option values.
	(dump_section_as_ctf): Fix typo checking dump_ctf_strtab_name
	variable.

libctf	* ctf-archive.c (ctf_arc_write): Avoid calling close twice on the
	same file descriptor.
2020-07-22 16:07:48 +01:00
Simon Marchi
a7b4ff4f0a gdb/jit: skip jit symbol lookup if already detected the symbols don't exist
To detect whether an objfile is a JITer, we lookup JIT interface
symbols in the objfile.  If an objfile does not have these symbols, we
conclude that it is not a JITer.  An objfile that does not have the
symbols will never have them.  Therefore, once we do a lookup and find
out that the objfile does not have JIT symbols, just set a flag so
that we can skip symbol lookup for that objfile the next time we reset
JIT breakpoints.

gdb/ChangeLog:
2020-07-22  Simon Marchi  <simon.marchi@polymtl.ca>
	    Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* objfiles.h (struct objfile) <skip_jit_symbol_lookup>: New field.
	* jit.c (jit_breakpoint_re_set_internal): Use the
	`skip_jit_symbol_lookup` field.
2020-07-22 15:56:08 +02:00
Simon Marchi
2340e834df gdb/jit: apply minor cleanup and modernization
gdb/ChangeLog:
2020-07-22  Simon Marchi  <simon.marchi@polymtl.ca>
	    Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* jit.c (jit_read_descriptor): Define the descriptor address once,
	use twice.
	(jit_breakpoint_deleted): Move the declaration of the loop variable
	`iter` into the loop header.
	(jit_breakpoint_re_set_internal): Move the declaration of the local
	variable `objf_data` to the first point of definition.
	(jit_event_handler): Move the declaration of local variables
	`code_entry`, `entry_addr`, and `objf` to their first point of use.
	Rename `objf` to `jited`.
2020-07-22 15:56:08 +02:00
Simon Marchi
c1072906f1 gdb/jit: remove jiter_objfile_data -> objfile back-link
This is no longer needed, remove it.

gdb/ChangeLog:
2020-07-22  Simon Marchi  <simon.marchi@polymtl.ca>

	* jit.h (struct jiter_objfile_data) <jiter_objfile_data, objfile>:
	Remove.
	* jit.c (get_jiter_objfile_data): Update.
2020-07-22 15:56:08 +02:00
Tankut Baris Aktemur
c8474dc353 gdb/jit: enable tracking multiple JITer objfiles
GDB's JIT handler stores an objfile (and data associated with it) per
program space to keep track of JIT breakpoint information.  This assumes
that there is at most one JITer objfile in the program space.  However,
there may be multiple.  If so, only the first JITer's hook breakpoints
would be realized and the JIT events from the other JITers would be
missed.

This patch removes that assumption, allowing an arbitrary number of
objfiles within a program space to be JITers.

- The "unique" program_space -> JITer objfile pointer in
  jit_program_space_data is removed.  In fact, jit_program_space_data
  becomes empty, so it is removed entirely.

- jit_breakpoint_deleted is modified, it now has to assume that any
  objfile in a program space is a potential JITer.  It now iterates on
  all objfiles, checking if they are indeed JITers, and if they are,
  whether the deleted breakpoint belongs to them.

- jit_breakpoint_re_set_internal also has to assume that any objfile in
  a program space is a potential JITer.  It creates (or updates) one
  jiter_objfile_data structure for each JITer it finds.

- Same for jit_inferior_init.  It now iterates all objfiles to read the
  initial JIT object list.

gdb/ChangeLog:
2020-07-22  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>
	    Simon Marchi  <simon.marchi@polymtl.ca>

	* jit.c (struct jit_program_space_data): Remove.
	(jit_program_space_key): Remove.
	(jiter_objfile_data::~jiter_objfile_data): Remove program space
	stuff.
	(get_jit_program_space_data): Remove.
	(jit_breakpoint_deleted): Iterate on all of the program space's
	objfiles.
	(jit_inferior_init): Likewise.
	(jit_breakpoint_re_set_internal): Likewise.  Also change return
	type to void.
	(jit_breakpoint_re_set): Pass current_program_space to
	jit_breakpoint_re_set_internal.

gdb/testsuite/ChangeLog:
2020-07-22  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* gdb.base/jit-reader-simple.exp: Add a scenario for a binary that
	loads two JITers.
2020-07-22 15:56:07 +02:00
Simon Marchi
77208eb7e2 gdb/jit: move cached_code_address and jit_breakpoint to jiter_objfile_data
This is in preparation for allowing more than one JITer objfile per
program space.  Once we do that, each JITer objfile will have its own
JIT breakpoint (on the __jit_debug_register_code function it provides).
The cached_code_address field is just the runtime / relocated address of
that symbol.

Since they are going to become JITer-objfile-specific and not
program-space-specific, move these fields from jit_program_space_data to
jiter_objfile_data.

gdb/ChangeLog:
2020-07-22  Simon Marchi  <simon.marchi@polymtl.ca>

	* jit.h (struct jiter_objfile_data) <cached_code_address,
	jit_breakpoint>: Move to here from ...
	* jit.c (jit_program_space_data): ... here.
	(jiter_objfile_data::~jiter_objfile_data): Update.
	(jit_breakpoint_deleted): Update.
	(jit_breakpoint_re_set_internal): Update.
2020-07-22 15:56:07 +02:00
Simon Marchi
8c1c720faa gdb/jit: apply some simplifications and assertions
Following patch "gdb/jit: split jit_objfile_data in two", there are some
simplifications we can make.  The invariants described there mean that
we can assume / assert some things instead of checking them using
conditionals.

If an instance of jiter_objfile_data exists for a given objfile, it's
because the required JIT interface symbols were found.  Therefore, in
~jiter_objfile_data, the `register_code` field can't be NULL.  It was
previously used to differentiate a jit_objfile_data object used for a
JITer vs a JITed.  We can remove that check.

If an instance of jiter_objfile_data exists for a given objfile, it's
because it's the sole JITer objfile in the scope of its program space
(jit_program_space_data::objfile points to it).  At the moment,
jit_breakpoint_re_set_internal won't create a second instance of
jiter_objfile_data for a given program space.  Therefore, it's not
necessary to check for `ps_data != NULL` in ~jiter_objfile_data: we know
a jit_program_space_data for that program space exists.  We also don't
need to check for `ps_data->objfile == this->objfile`, because we know
the objfile is the sole JITer in this program space.  Replace these two
conditions with assertions.

A pre-condition for calling the jit_read_descriptor function (which is
respected in the two call sites) is that the objfile `jiter` _is_ a
JITer - it already has a jiter_objfile_data attached to it.  When a
jiter_objfile_data exists, its `descriptor` field is necessarily set:
had the descriptor symbol not been found, jit_breakpoint_re_set_internal
would not have created the jiter_objfile_data.  Remove the check and
early return in jit_read_descriptor.  Access objfile's `jiter_data` field
directly instead of calling `get_jiter_objfile_data` (which creates the
jiter_objfile_data if it doesn't exist yet) and assert that the result
is not nullptr.

Finally, `jit_event_handler` is always passed a JITer objfile.  So, add
an assertion to ensure that.

gdb/ChangeLog:
2020-07-22  Simon Marchi  <simon.marchi@polymtl.ca>

	* jit.c (jiter_objfile_data::~jiter_objfile_data): Remove some
	checks.
	(jit_read_descriptor): Remove NULL check.
	(jit_event_handler): Add an assertion.
2020-07-22 15:56:07 +02:00
Simon Marchi
0e74a041c0 gdb/jit: split jit_objfile_data in two
The jit_objfile_data is currently used to hold information about both
objfiles that are the result of JIT compilation (JITed) and objfiles
that can produce JITed objfiles (JITers).  I think that this double use
of the type is confusing, and that things would be more obvious if we
had one type for each role.

This patch splits it into:

- jited_objfile_data: for data about an objfile that is the result of a
  JIT compilation
- jiter_objfile_data: for data about an objfile which produces JITed
  objfiles

There are now two JIT-related fields in an objfile, one for each kind.
With this change, the following invariants hold:

- an objfile has a non-null `jiter_data` field iff it defines the required
  symbols of the JIT interface
- an objfile has a non-null `jited_data` field iff it is the product of
  JIT compilation (has been produced by some JITer)

gdb/ChangeLog:
2020-07-22  Simon Marchi  <simon.marchi@polymtl.ca>

	* jit.h (struct jit_objfile_data):  Split into...
	(struct jiter_objfile_data): ... this ...
	(struct jited_objfile_data): ... and this.
	* objfiles.h (struct objfile) <jit_data>: Remove.
	<jiter_data, jited_data>: New fields.
	* jit.c (jit_objfile_data::~jit_objfile_data): Rename to ...
	(jiter_objfile_data::~jiter_objfile_data): ... this.
	(get_jit_objfile_data): Rename to ...
	(get_jiter_objfile_data): ... this.
	(add_objfile_entry): Update.
	(jit_read_descriptor): Use get_jiter_objfile_data.
	(jit_find_objf_with_entry_addr): Use objfile's jited_data field.
	(jit_breakpoint_re_set_internal): Use get_jiter_objfile_data.
	(jit_inferior_exit_hook): Use objfile's jited_data field.
2020-07-22 15:56:07 +02:00
Simon Marchi
238b5c9f08 gdb/jit: link to jit_objfile_data directly from the objfile struct
Remove the use of objfile_data to associate a jit_objfile_data with an
objfile.  Instead, directly link to a jit_objfile_data from an objfile
struct.  The goal is to eliminate unnecessary abstraction.

The free_objfile_data function naturally becomes the destructor of
jit_objfile_data.  However, free_objfile_data accesses the objfile to
which the data is attached, which the destructor of jit_objfile_data
doesn't have access to.  To work around this, add a backlink to the
owning objfile in jit_objfile_data.  This is however temporary, it goes
away in a subsequent patch.

gdb/ChangeLog:
2020-07-22  Simon Marchi  <simon.marchi@polymtl.ca>

	* jit.h: Forward-declare `struct minimal_symbol`.
	(struct jit_objfile_data): Migrate to here from jit.c; also add a
	constructor, destructor, and an objfile* field.
	* jit.c (jit_objfile_data): Remove.
	(struct jit_objfile_data): Migrate from here to jit.h.
	(jit_objfile_data::~jit_objfile_data): New destructor
	implementation with code moved from free_objfile_data.
	(free_objfile_data): Delete.
	(get_jit_objfile_data): Update to use the jit_data field of objfile.
	(jit_find_objf_with_entry_addr): Ditto.
	(jit_inferior_exit_hook): Ditto.
	(_initialize_jit): Remove the call to
	register_objfile_data_with_cleanup.
	* objfiles.h (struct objfile) <jit_data>: New field.
2020-07-22 15:56:06 +02:00
Tankut Baris Aktemur
fe053b9e85 gdb/jit: pass the jiter objfile as an argument to jit_event_handler
This is a refactoring that adds a new parameter to the `jit_event_handler`
function: the JITer objfile.  The goal is to distinguish which JITer
triggered the JIT event, in case there are multiple JITers -- a capability
that is added in a subsequent patch.

gdb/ChangeLog:
2020-07-22  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* jit.h: Forward-declare `struct objfile`.
	(jit_event_handler): Add a second parameter, the JITer objfile.
	* jit.c (jit_read_descriptor): Change the signature to take the
	JITer objfile as an argument instead of the jit_program_space_data.
	(jit_inferior_init): Update the call to jit_read_descriptor.
	(jit_event_handler): Use the new JITer objfile argument when calling
	jit_read_descriptor.
	* breakpoint.c (handle_jit_event): Update the call to
	jit_event_handler to pass the JITer objfile.
2020-07-22 15:56:06 +02:00
Maciej W. Rozycki
39fdda0744 MIPS/GAS/testsuite: Fix JALR relocation tests for IRIX targets
With IRIX targets the JALR hint relocation is not produced for the o32
ABI, where it is considered a GNU extension.  Consequently several tests
fail as the output produced by GAS fails to match patterns expecting the
relocation to be present where appropriate, even though output produced
is indeed correct.

As the absence of the relocation is expected, fix the tests by providing
respective alternative dump patterns with any JALR relocations removed,
removing numerous failures with `*-*-irix*' targets:

FAIL: MIPS jal-svr4pic (interaptiv-mr2)
FAIL: MIPS jal-svr4pic (micromips)
FAIL: MIPS jal-svr4pic (mips1)
FAIL: MIPS jal-svr4pic (mips2)
FAIL: MIPS jal-svr4pic (mips3)
FAIL: MIPS jal-svr4pic (mips4)
FAIL: MIPS jal-svr4pic (mips5)
FAIL: MIPS jal-svr4pic (mips32)
FAIL: MIPS jal-svr4pic (mips32r2)
FAIL: MIPS jal-svr4pic (mips32r3)
FAIL: MIPS jal-svr4pic (mips32r5)
FAIL: MIPS jal-svr4pic (mips32r6)
FAIL: MIPS jal-svr4pic (mips64)
FAIL: MIPS jal-svr4pic (mips64r2)
FAIL: MIPS jal-svr4pic (mips64r3)
FAIL: MIPS jal-svr4pic (mips64r5)
FAIL: MIPS jal-svr4pic (mips64r6)
FAIL: MIPS jal-svr4pic (octeon)
FAIL: MIPS jal-svr4pic (octeon2)
FAIL: MIPS jal-svr4pic (octeon3)
FAIL: MIPS jal-svr4pic (octeonp)
FAIL: MIPS jal-svr4pic (r3000)
FAIL: MIPS jal-svr4pic (r3900)
FAIL: MIPS jal-svr4pic (r4000)
FAIL: MIPS jal-svr4pic (r5900)
FAIL: MIPS jal-svr4pic (sb1)
FAIL: MIPS jal-svr4pic (vr5400)
FAIL: MIPS jal-svr4pic (xlr)
FAIL: MIPS jal-svr4pic noreorder (interaptiv-mr2)
FAIL: MIPS jal-svr4pic noreorder (micromips)
FAIL: MIPS jal-svr4pic noreorder (mips1)
FAIL: MIPS jal-svr4pic noreorder (mips2)
FAIL: MIPS jal-svr4pic noreorder (mips3)
FAIL: MIPS jal-svr4pic noreorder (mips4)
FAIL: MIPS jal-svr4pic noreorder (mips5)
FAIL: MIPS jal-svr4pic noreorder (mips32)
FAIL: MIPS jal-svr4pic noreorder (mips32r2)
FAIL: MIPS jal-svr4pic noreorder (mips32r3)
FAIL: MIPS jal-svr4pic noreorder (mips32r5)
FAIL: MIPS jal-svr4pic noreorder (mips32r6)
FAIL: MIPS jal-svr4pic noreorder (mips64)
FAIL: MIPS jal-svr4pic noreorder (mips64r2)
FAIL: MIPS jal-svr4pic noreorder (mips64r3)
FAIL: MIPS jal-svr4pic noreorder (mips64r5)
FAIL: MIPS jal-svr4pic noreorder (mips64r6)
FAIL: MIPS jal-svr4pic noreorder (octeon)
FAIL: MIPS jal-svr4pic noreorder (octeon2)
FAIL: MIPS jal-svr4pic noreorder (octeon3)
FAIL: MIPS jal-svr4pic noreorder (octeonp)
FAIL: MIPS jal-svr4pic noreorder (r3000)
FAIL: MIPS jal-svr4pic noreorder (r3900)
FAIL: MIPS jal-svr4pic noreorder (r4000)
FAIL: MIPS jal-svr4pic noreorder (r5900)
FAIL: MIPS jal-svr4pic noreorder (sb1)
FAIL: MIPS jal-svr4pic noreorder (vr5400)
FAIL: MIPS jal-svr4pic noreorder (xlr)
FAIL: MIPS R3000 jal-xgot
FAIL: MIPS -mabi=32 test 2 (SVR4 PIC)
FAIL: gas/mips/jalr2
FAIL: Relax microMIPS branches (pic)
FAIL: Relax microMIPS branches (insn32 mode, pic)

Strictly speaking no MIPSr6 or microMIPS target is supported by IRIX,
but GAS supports such configurations on the basis of uniformity, so
provide the relevant patterns too rather than excluding the combinations
from testing.

	gas/
	* testsuite/gas/mips/jal-svr4pic-irix.d: New file.
	* testsuite/gas/mips/mips1@jal-svr4pic-irix.d: New file.
	* testsuite/gas/mips/mipsr6@jal-svr4pic-irix.d: New file.
	* testsuite/gas/mips/micromips@jal-svr4pic-irix.d: New file.
	* testsuite/gas/mips/r3000@jal-svr4pic-irix.d: New file.
	* testsuite/gas/mips/jal-svr4pic-local-irix.d: New file.
	* testsuite/gas/mips/mips1@jal-svr4pic-local-irix.d: New file.
	* testsuite/gas/mips/micromips@jal-svr4pic-local-irix.d: New
	file.
	* testsuite/gas/mips/r3000@jal-svr4pic-local-irix.d: New file.
	* testsuite/gas/mips/jal-svr4pic-noreorder-irix.d: New file.
	* testsuite/gas/mips/mips1@jal-svr4pic-noreorder-irix.d: New
	file.
	* testsuite/gas/mips/mipsr6@jal-svr4pic-noreorder-irix.d: New
	file.
	* testsuite/gas/mips/micromips@jal-svr4pic-noreorder-irix.d: New
	file.
	* testsuite/gas/mips/r3000@jal-svr4pic-noreorder-irix.d: New
	file.
	* testsuite/gas/mips/jal-xgot-irix.d: New file.
	* testsuite/gas/mips/jalr2-irix.d: New file.
	* testsuite/gas/mips/micromips-branch-relax-insn32-pic-irix.d:
	New file.
	* testsuite/gas/mips/micromips-branch-relax-pic-irix.d: New
	file.
	* testsuite/gas/mips/mips-abi32-pic2-irix.d: New file.
	* testsuite/gas/mips/jal-svr4pic-local.d: Don't exclude
	`*-*-irix*' targets.  Add source file designator.
	* testsuite/gas/mips/mips1@jal-svr4pic-local.d: Don't exclude
	`*-*-irix*' targets.
	* testsuite/gas/mips/r3000@jal-svr4pic-local.d: Likewise.
	* testsuite/gas/mips/micromips@jal-svr4pic-local.d: Likewise.
	* testsuite/gas/mips/jalr2.d: Add name designator.
	* testsuite/gas/mips/mips.exp: Use respective IRIX variants for
	tests involving the JALR relocation throughout.
2020-07-22 12:46:00 +01:00
Maciej W. Rozycki
b83d958fc7 MIPS/GAS/testsuite: Use a helper variable for IRIX/non-IRIX test selection
Define a helper variable for IRIX/non-IRIX test selection and use it
with the PR 14798 test case.

	gas/
	* testsuite/gas/mips/mips.exp: Use a helper variable for
	IRIX/non-IRIX test selection.
2020-07-22 12:46:00 +01:00
Pedro Alves
028a46039a gdbserver: handle running threads in qXfer:threads:read
On some systems, the gdb.multi/multi-target.exp testcase occasionally
fails like so:

 Running src/gdb/testsuite/gdb.multi/multi-target.exp ...
 FAIL: gdb.multi/multi-target.exp: info-inferiors: multi_process=on: inferior 1: info connections
 FAIL: gdb.multi/multi-target.exp: info-inferiors: multi_process=on: inferior 1: info inferiors
 FAIL: gdb.multi/multi-target.exp: info-inferiors: multi_process=on: inferior 2: info connections
 FAIL: gdb.multi/multi-target.exp: info-inferiors: multi_process=on: inferior 2: info inferiors
 FAIL: gdb.multi/multi-target.exp: info-inferiors: multi_process=on: inferior 3: inferior 3
 ... many more cascading fails.

The problem starts when the testcase runs an inferior against GDBserver:

 (gdb) run
 Starting program: build/gdb/testsuite/outputs/gdb.multi/multi-target/multi-target
 Reading /lib64/ld-linux-x86-64.so.2 from remote target...
 warning: File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead.
 Reading /lib64/ld-linux-x86-64.so.2 from remote target...
 Reading /lib64/ld-2.31.so from remote target...
 Reading /lib64/.debug/ld-2.31.so from remote target...
 Reading /usr/lib/debug//lib64/ld-2.31.so from remote target...
 Reading /usr/lib/debug/lib64//ld-2.31.so from remote target...
 Reading target:/usr/lib/debug/lib64//ld-2.31.so from remote target...
 Reading /lib/x86_64-linux-gnu/libpthread.so.0 from remote target...
 Reading /lib/x86_64-linux-gnu/libc.so.6 from remote target...
 Reading /lib/x86_64-linux-gnu/libc-2.31.so from remote target...
 Reading /lib/x86_64-linux-gnu/.debug/libc-2.31.so from remote target...
 Reading /usr/lib/debug//lib/x86_64-linux-gnu/libc-2.31.so from remote target...
 Reading /usr/lib/debug//lib/x86_64-linux-gnu/libc-2.31.so from remote target...
 Remote connection closed
 ...

Note the "Remote connection closed" message.  That means GDBserver
exited abruptly.

I traced it down to the fact that GDB fetches the thread list from
GDBserver while the main thread of the process is still running.  On
my main system where I wrote the testcase, I have not observed the
failure because it is slow enough that the thread stops before
GDBserver fetches the thread list in the problem scenario which I'll
describe below.

With some --remote-debug logging from GDBserver side, we see the last
packets before the connection closes:

 ...
 getpkt ("vCont;c");  [no ack sent]
 putpkt ("$OK#9a"); [noack mode]
 getpkt ("Tp10f9a.10f9a");  [no ack sent]
 putpkt ("$OK#9a"); [noack mode]
 getpkt ("Hgp0.0");  [no ack sent]
 putpkt ("$OK#9a"); [noack mode]
 getpkt ("qXfer:threads:read::0,1000");  [no ack sent]

Note the vCont;c , which sets the program running, and then a
qXfer:threads:read packet at the end.

The problem happens when the thread list refresh (qXfer:threads:read)
is sent just while the main thread is running and it still hasn't
initialized its libpthread id internally.  In that state, the main
thread's lwp will remain with the thread_known flag clear.  See in
find_one_thread:

  /* If the new thread ID is zero, a final thread ID will be available
     later.  Do not enable thread debugging yet.  */
  if (ti.ti_tid == 0)
    return 0;

Now, back in server.cc, to handle the qXfer:threads:read, we reach
handle_qxfer_threads -> handle_qxfer_threads_proper, and the latter
then calls handle_qxfer_threads_worker for each known thread.  In
handle_qxfer_threads_worker, we call target_thread_handle.  This ends
up in thread_db_thread_handle, here:

  if (!lwp->thread_known && !find_one_thread (thread->id))
    return false;

Since the thread ID isn't known yet, we call find_one_thread.  This
calls into libthread_db.so, which accesses memory.  Because the
current thread is running, that fails and we throw an error, here:

  /* Get information about this thread.  */
  err = thread_db->td_ta_map_lwp2thr_p (thread_db->thread_agent, lwpid, &th);
  if (err != TD_OK)
    error ("Cannot get thread handle for LWP %d: %s",
	   lwpid, thread_db_err_str (err));

The current design is that whenever GDB-facing packets/requests need
to accesses memory, server.cc is supposed to prepare the target for
the access.  See gdb_read_memory / gdb_write_memory.  This preparation
means pausing threads if in non-stop mode (someday we could lift this
requirement, but we will still need to pause to access registers or do
other related ptrace accesses like PTRACE_GET_THREAD_AREA).  Note that
the multi-target.exp testcase forces "maint set target-non-stop on".

So the fix here is to prepare the target to access memory when
handling qXfer:threads:read too.

gdbserver/ChangeLog:

	* inferiors.cc (switch_to_process): New, moved here from
	thread-db.cc, and made extern.
	* inferiors.h (switch_to_process): Declare.
	* server.cc: Include "gdbsupport/scoped_restore.h".
	(handle_qxfer_threads_proper): Now returns bool.  Prepare to
	access memory around target calls.
	(handle_qxfer_threads): Handle errors.
	* thread-db.cc (switch_to_process): Moved to inferiors.cc.
2020-07-22 12:32:53 +01:00
H.J. Lu
0e6a3f07f5 ld: Properly override the IR definition
We change the previous definition in the IR object to undefweak only
after all LTO symbols have been read.

include/

	PR ld/26262
	PR ld/26267
	* bfdlink.h (bfd_link_info): Add lto_all_symbols_read.

ld/

	PR ld/26262
	PR ld/26267
	* ldlang.c (lang_process): Set lto_all_symbols_read after all
	LTO IR symbols have been read.
	* plugin.c (plugin_notice): Override the IR definition only if
	all LTO IR symbols have been read or the new definition is
	non-weak and the the IR definition is weak
	* testsuite/ld-plugin/lto.exp: Run PR ld/26262 and ld/26267
	tests.
	* testsuite/ld-plugin/pr26262a.c: New file.
	* testsuite/ld-plugin/pr26262b.c: Likewise.
	* testsuite/ld-plugin/pr26262c.c: Likewise.
	* testsuite/ld-plugin/pr26267.err: Likewise.
	* testsuite/ld-plugin/pr26267a.c: Likewise.
	* testsuite/ld-plugin/pr26267b.c: Likewise.
	* testsuite/ld-plugin/pr26267c.c: Likewise.
2020-07-22 03:49:17 -07:00
Max Filippov
1ad2776d3d bfd: xtensa: pr26246: fix removed_literal_compare
2020-07-22  Max Filippov  <jcmvbkbc@gmail.com>
bfd/
	PR 26246
	* elf32-xtensa.c (removed_literal_compare): Use correct pointer
	type for the first function argument. Rename pointers to reflect
	that they have distinct types.
2020-07-22 02:58:34 -07:00
John Baldwin
4cec0c6689 Retire the now-unused gdbarch handle_segmentation_fault hook.
* gdbarch.c: Regenerate.
	* gdbarch.h: Regenerate.
	* gdbarch.sh (handle_segmentation_fault): Remove method.
	* infrun.c (handle_segmentation_fault): Remove.
	(print_signal_received_reason): Remove call to
	handle_segmentation_fault.
2020-07-21 17:28:16 -07:00
John Baldwin
0e42f66a30 Migrate the sparc64 ADI handle_segmentation_fault hook to report_signal_info.
gdb/ChangeLog:

	* sparc64-linux-tdep.c (sparc64_linux_handle_segmentation_fault):
	Rename to sparc64_linux_report_signal_info and add siggnal
	argument.
	(sparc64_linux_init_abi): Use sparc64_linux_report_signal_info
	instead of sparc64_linux_handle_segmentation_fault.
2020-07-21 17:28:16 -07:00
John Baldwin
77bdfeb2e6 Migrate the x86 MPX handle_segmentation_fault hook to report_signal_info.
gdb/ChangeLog:

	* amd64-linux-tdep.c (amd64_linux_init_abi_common): Use
	i386_linux_report_signal_info instead of
	i386_linux_handle_segmentation_fault.
	* i386-linux-tdep.c (i386_linux_handle_segmentation_fault): Rename
	to i386_linux_report_signal_info and add siggnal argument.
	(i386_linux_init_abi): Use i386_linux_report_signal_info instead
	of i386_linux_handle_segmentation_fault.
	* i386-linux-tdep.h (i386_linux_handle_segmentation_fault): Rename
	to i386_linux_report_signal_info and add siggnal argument.
2020-07-21 17:28:16 -07:00
John Baldwin
ad97bfc533 Report architecture-specific signal information for core files.
When opening a core file, if the process terminated due to a signal,
invoke the gdbarch report_signal_info hook to report
architecture-specific information about the signal.

gdb/ChangeLog:

	* corelow.c (core_target_open): Invoke gdbarch report_signal_info
	hook if present.
2020-07-21 17:28:16 -07:00
John Baldwin
272bb05cc5 Add a new gdbarch hook to report additional signal information.
This is a more general version of the existing handle_segmentation_fault
hook that is able to report information for an arbitrary signal, not
just SIGSEGV.

gdb/ChangeLog:

	* gdbarch.c: Regenerate.
	* gdbarch.h: Regenerate.
	* gdbarch.sh (report_signal_info): New method.
	* infrun.c (print_signal_received_reason): Invoke gdbarch
	report_signal_info hook if present.
2020-07-21 17:28:16 -07:00
GDB Administrator
98f5f7740a Automatic date update in version.in 2020-07-22 00:00:06 +00:00