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The recent change to detect duplicate enum values and return ECTF_DUPLICATE
when found turns out to perturb a great many callers. In particular, the
pahole-created kernel BTF has the same problem we historically did, and
gleefully emits duplicated enum constants in profusion. Handling the
resulting duplicate errors from BTF -> CTF converters reasonably is
unreasonably difficult (it amounts to forcing them to skip some types or
reimplement the deduplicator).
So let's step back a bit. What we care about mostly is that the
deduplicator treat enums with conflicting enumeration constants as
conflicting types: programs that want to look up enumeration constant ->
value mappings using the new APIs to do so might well want the same checks
to apply to any ctf_add_* operations they carry out (and since they're
*using* the new APIs, added at the same time as this restriction was
imposed, there is likely to be no negative consequence of this).
So we want some way to allow processes that know about duplicate detection
to opt into it, while allowing everyone else to stay clear of it: but we
want ctf_link to get this behaviour even if its caller has opted out.
So add a new concept to the API: dict-wide CTF flags, set via
ctf_dict_set_flag, obtained via ctf_dict_get_flag. They are not bitflags
but simple arbitrary integers and an on/off value, stored in an unspecified
manner (the one current flag, we translate into an LCTF_* flag value in the
internal ctf_dict ctf_flags word). If you pass in an invalid flag or value
you get a new ECTF_BADFLAG error, so the caller can easily tell whether
flags added in future are valid with a particular libctf or not.
We check this flag in ctf_add_enumerator, and set it around the link
(including on child per-CU dicts). The newish enumerator-iteration test is
souped up to check the semantics of the flag as well.
The fact that the flag can be set and unset at any time has curious
consequences. You can unset the flag, insert a pile of duplicates, then set
it and expect the new duplicates to be detected, not only by
ctf_add_enumerator but also by ctf_lookup_enumerator. This means we now
have to maintain the ctf_names and conflicting_enums enum-duplication
tracking as new enums are added, not purely as the dict is opened.
Move that code out of init_static_types_internal and into a new
ctf_track_enumerator function that addition can also call.
(None of this affects the file format or serialization machinery, which has
to be able to handle duplicate enumeration constants no matter what.)
include/
* ctf-api.h (CTF_ERRORS) [ECTF_BADFLAG]: New.
(ECTF_NERR): Update.
(CTF_STRICT_NO_DUP_ENUMERATORS): New flag.
(ctf_dict_set_flag): New function.
(ctf_dict_get_flag): Likewise.
libctf/
* ctf-impl.h (LCTF_STRICT_NO_DUP_ENUMERATORS): New flag.
(ctf_track_enumerator): Declare.
* ctf-dedup.c (ctf_dedup_emit_type): Set it.
* ctf-link.c (ctf_create_per_cu): Likewise.
(ctf_link_deduplicating_per_cu): Likewise.
(ctf_link): Likewise.
(ctf_link_write): Likewise.
* ctf-subr.c (ctf_dict_set_flag): New function.
(ctf_dict_get_flag): New function.
* ctf-open.c (init_static_types_internal): Move enum tracking to...
* ctf-create.c (ctf_track_enumerator): ... this new function.
(ctf_add_enumerator): Call it.
* libctf.ver: Add the new functions.
* testsuite/libctf-lookup/enumerator-iteration.c: Test them.
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Commit 483546ce4f3 ("libctf: make ctf_serialize() actually serialize")
accidentally broke dict compression. There were two bugs:
- ctf_arc_write_one_ctf was still making its own decision about
whether to compress the dict via direct ctf_size comparison, which is
unfortunate because now that it no longer calls ctf_serialize itself,
ctf_size is always zero when it does this: it should let the writing
functions decide on the threshold, which they contain code to do which is
simply not used for lack of one trivial wrapper to write to an fd and
also provide a compression threshold
- ctf_write_mem, the function underlying all writing as of the commit
above, was calling zlib's compressBound and avoiding compression if this
returned a value larger than the input. Unfortunately compressBound does
not do a trial compression and determine whether the result is
compressible: it just adds zlib header sizes to the value passed in, so
our test would *always* have concluded that the value was incompressible!
Avoid by simply always compressing if the raw size is larger than the
threshold: zlib is quite clever enough to avoid actually compressing
if the data is incompressible.
Add a testcase for this.
libctf/
* ctf-impl.h (ctf_write_thresholded): New...
* ctf-serialize.c (ctf_write_thresholded): ... defined here,
a wrapper around...
(ctf_write_mem): ... this. Don't check compressibility.
(ctf_compress_write): Reimplement as a ctf_write_thresholded
wrapper.
(ctf_write): Likewise.
* ctf-archive.c (arc_write_one_ctf): Just call
ctf_write_thresholded rather than trying to work out whether
to compress.
* testsuite/libctf-writable/ctf-compressed.*: New test.
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In commit 149ce5c263616e65 we introduced the concept of "movable" refs,
which are refs that can be moved in batches, to let us maintain valid ref
lists even when adding refs to blocks of memory that can be realloced (which
is any type containing a vlen which can expand, like names contained within
enum or struct members). Movable refs need a backpointer to the movable
refs dynhash for this dict; since non-movable refs are very common, we tried
to save memory by having a slightly bigger struct for moveable refs with a
backpointer in it, and casting appropriately, indicating which sort of ref
we were dealing with via a flag on the atom.
Unfortunately this doesn't work reliably, because you can perfectly well
have a string ("foo", say) which has both non-movable refs (say, an external
symbol and a variable name) and movable refs (say, a structure member name)
to the same atom. Indicate which struct we're dealing with with an atom
flag and suddenly you're casting a ctf_str_atom_ref to a
ctf_str_atom_ref_movable (which is bigger) and dereferencing random memory
off the end of it and interpreting it as a backpointer to the movable refs
dynhash. This is unlikely to work well.
So bite the bullet and split refs into two separate lists, one for movable
refs, one for immovable refs. It means some annoying code duplication, but
there's not very much of it, and it means we can keep the movable refs
hashtab (which in turn means we don't have to do linear searches to find all
relevant refs when moving refs, which in turn means that
structure/union/enum member additions remain amortized O(n) time, not
O(n^2).
Callers can now purge movable and non-movable refs independently of each
other. We don't use this yet, but a use is coming.
libctf/
* ctf-impl.h (CTF_STR_ATOM_MOVABLE): Delete.
(struct ctf_str_atom) [csa_movable_refs]: New.
(struct ctf_dict): Adjust comment.
(ctf_str_purge_refs): Add MOVABLE arg.
* ctf-string.c (ctf_str_purge_movable_atom_refs): Split out of...
(ctf_str_purge_atom_refs): ... this.
(ctf_str_free_atom): Call it.
(ctf_str_purge_one_atom_refs): Likewise.
(aref_create): Adjust accordingly.
(ctf_str_move_refs): Likewise.
(ctf_str_remove_ref): Remove movable refs too, including
deleting the ref from ctf_str_movable_refs.
(ctf_str_purge_refs): Add MOVABLE arg.
(ctf_str_update_refs): Update movable refs.
(ctf_str_write_strtab): Check, and purge, movable refs.
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The PARENTS arg is carefully passed down through all the layers of hash
functions and then never used for anything. (In the distant past it was
used for cycle detection, but the algorithm eventually committed doesn't
need to do cycle detection...)
The PARENTS arg is still used by ctf_dedup_emit(), but even there we can
loosen the requirements and state that you can just leave entries
corresponding to dicts with no parents at zero (which will be useful
in an upcoming commit).
libctf/
* ctf-dedup.c (ctf_dedup_hash_type): Drop PARENTS arg.
(ctf_dedup_rhash_type): Likewise.
(ctf_dedup): Likewise.
(ctf_dedup_emit_struct_members): Mention what you can do to
PARENTS entries for parent dicts.
* ctf-impl.h (ctf_dedup): Adjust accordingly.
* ctf-link.c (ctf_link_deduplicating_per_cu): Likewise.
(ctf_link_deduplicating): Likewise.
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Three new functions for looking up the enum type containing a given
enumeration constant, and optionally that constant's value.
The simplest, ctf_lookup_enumerator, looks up a root-visible enumerator by
name in one dict: if the dict contains multiple such constants (which is
possible for dicts created by older versions of the libctf deduplicator),
ECTF_DUPLICATE is returned.
The next simplest, ctf_lookup_enumerator_next, is an iterator which returns
all enumerators with a given name in a given dict, whether root-visible or
not.
The most elaborate, ctf_arc_lookup_enumerator_next, finds all
enumerators with a given name across all dicts in an entire CTF archive,
whether root-visible or not, starting looking in the shared parent dict;
opened dicts are cached (as with all other ctf_arc_*lookup functions) so
that repeated use does not incur repeated opening costs.
All three of these return enumerator values as int64_t: unfortunately, API
compatibility concerns prevent us from doing the same with the other older
enum-related functions, which all return enumerator constant values as ints.
We may be forced to add symbol-versioning compatibility aliases that fix the
other functions in due course, bumping the soname for platforms that do not
support such things.
ctf_arc_lookup_enumerator_next is implemented as a nested ctf_archive_next
iterator, and inside that, a nested ctf_lookup_enumerator_next iterator
within each dict. To aid in this, add support to ctf_next_t iterators for
iterators that are implemented in terms of two simultaneous nested iterators
at once. (It has always been possible for callers to use as many nested or
semi-overlapping ctf_next_t iterators as they need, which is one of the
advantages of this style over the _iter style that calls a function for each
thing iterated over: the iterator change here permits *ctf_next_t iterators
themselves* to be implemented by iterating using multiple other iterators as
part of their internal operation, transparently to the caller.)
Also add a testcase that tests all these functions (which is fairly easy
because ctf_arc_lookup_enumerator_next is implemented in terms of
ctf_lookup_enumerator_next) in addition to enumeration addition in
ctf_open()ed dicts, ctf_add_enumerator duplicate enumerator addition, and
conflicting enumerator constant deduplication.
include/
* ctf-api.h (ctf_lookup_enumerator): New.
(ctf_lookup_enumerator_next): Likewise.
(ctf_arc_lookup_enumerator_next): Likewise.
libctf/
* libctf.ver: Add them.
* ctf-impl.h (ctf_next_t) <ctn_next_inner>: New.
* ctf-util.c (ctf_next_copy): Copy it.
(ctf_next_destroy): Destroy it.
* ctf-lookup.c (ctf_lookup_enumerator): New.
(ctf_lookup_enumerator_next): New.
* ctf-archive.c (ctf_arc_lookup_enumerator_next): New.
* testsuite/libctf-lookup/enumerator-iteration.*: New test.
* testsuite/libctf-lookup/enum-ctf-2.c: New test CTF, used by the
above.
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This was always an error, because the ctn_fp routinely has errors set on it,
which is not something you can (or should) do to a const object.
libctf/
* ctf-impl.h (ctf_next_) <cu.ctn_fp>: Make non-const.
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libctf has long prohibited addition of enums with overlapping constants in a
single enum, but now that we are properly considering enums with overlapping
constants to be conflciting types, we can go further and prohibit addition
of enumeration constants to a dict if they already exist in any enum in that
dict: the same rules as C itself.
We do this in a fashion vaguely similar to what we just did in the
deduplicator, by considering enumeration constants as identifiers and adding
them to the core type/identifier namespace, ctf_dict_t.ctf_names. This is a
little fiddly, because we do not want to prohibit opening of existing dicts
into which the deduplicator has stuffed enums with overlapping constants!
We just want to prohibit the addition of *new* enumerators that violate that
rule. Even then, it's fine to add overlapping enumerator constants as long
as at least one of them is in a non-root type. (This is essential for
proper deduplicator operation in cu-mapped mode, where multiple compilation
units can be smashed into one dict, with conflicting types marked as
hidden: these types may well contain overlapping enumerators.)
So, at open time, keep track of all enums observed, then do a third pass
through the enums alone, adding each enumerator either to the ctf_names
table as a mapping from the enumerator name to the enum it is part of (if
not already present), or to a new ctf_conflicting_enums hashtable that
tracks observed duplicates. (The latter is not used yet, but will be soon.)
(We need to do a third pass because it's quite possible to have an enum
containing an enumerator FOO followed by a type FOO: since they're processed
in order, the enumerator would be processed before the type, and at that
stage it seems nonconflicting. The easiest fix is to run through the
enumerators after all type names are interned.)
At ctf_add_enumerator time, if the enumerator to which we are adding a type
is root-visible, check for an already-present name and error out if found,
then intern the new name in the ctf_names table as is done at open time.
(We retain the existing code which scans the enum itself for duplicates
because it is still an error to add an enumerator twice to a
non-root-visible enum type; but we only need to do this if the enum is
non-root-visible, so the cost of enum addition is reduced.)
Tested in an upcoming commit.
libctf/
* ctf-impl.h (ctf_dict_t) <ctf_names>: Augment comment.
<ctf_conflicting_enums>: New.
(ctf_dynset_elements): New.
* ctf-hash.c (ctf_dynset_elements): Implement it.
* ctf-open.c (init_static_types): Split body into...
(init_static_types_internal): ... here. Count enumerators;
keep track of observed enums in pass 2; populate ctf_names and
ctf_conflicting_enums with enumerators in a third pass.
(ctf_dict_close): Free ctf_conflicting_enums.
* ctf-create.c (ctf_add_enumerator): Prohibit addition of duplicate
enumerators in root-visible enum types.
include/
* ctf-api.h (CTF_ADD_NONROOT): Describe what non-rootness
means for enumeration constants.
(ctf_add_enumerator): The name is not a misnomer.
We now require that enumerators have unique names.
Document the non-rootness of enumerators.
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The CTF deduplicator was not considering enumerators inside enum types to be
things that caused type conflicts, so if the following two TUs were linked
together, you would end up with the following in the resulting dict:
1.c:
enum foo { A, B };
2.c:
enum bar { A, B };
linked:
enum foo { A, B };
enum bar { A, B };
This does work -- but it's not something that's valid C, and the general
point of the shared dict is that it is something that you could potentially
get from any valid C TU.
So consider such types to be conflicting, but obviously don't consider
actually identical enums to be conflicting, even though they too have (all)
their identifiers in common. This involves surprisingly little code. The
deduplicator detects conflicting types by counting types in a hash table of
hash tables:
decorated identifier -> (type hash -> count)
where the COUNT is the number of times a given hash has been observed: any
name with more than one hash associated with it is considered conflicting
(the count is used to identify the most common such name for promotion to
the shared dict).
Before now, those identifiers were all the identifiers of types (possibly
decorated with their namespace on the front for enumerator identifiers), but
we can equally well put *enumeration constant names* in there, undecorated
like the identifiers of types in the global namespace, with the type hash
being the hash of each enum containing that enumerator. The existing
conflicting-type-detection code will then accurately identify distinct enums
with enumeration constants in common. The enum that contains the most
commonly-appearing enumerators will be promoted to the shared dict.
libctf/
* ctf-impl.h (ctf_dedup_t) <cd_name_counts>: Extend comment.
* ctf-dedup.c (ctf_dedup_count_name): New, split out of...
(ctf_dedup_populate_mappings): ... here. Call it for all
* enumeration constants in an enum as well as types.
ld/
* testsuite/ld-ctf/enum-3.c: New test CTF.
* testsuite/ld-ctf/enum-4.c: Likewise.
* testsuite/ld-ctf/overlapping-enums.d: New test.
* testsuite/ld-ctf/overlapping-enums-2.d: Likewise.
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ctf_serialize() evolved from the old ctf_update(), which mutated the
in-memory CTF dict to make all the dynamic in-memory types into static,
unchanging written-to-the-dict types (by deserializing and reserializing
it): back in the days when you could only do type lookups on static types,
this meant you could see all the types you added recently, at the small,
small cost of making it impossible to change those older types ever again
and inducing an amortized O(n^2) cost if you actually wanted to add
references to types you added at arbitrary times to later types.
It also reset things so that ctf_discard() would throw away only types you
added after the most recent ctf_update() call.
Some time ago this was all changed so that you could look up dynamic types
just as easily as static types: ctf_update() changed so that only its
visible side-effect of affecting ctf_discard() remained: the old
ctf_update() was renamed to ctf_serialize(), made internal to libctf, and
called from the various functions that wrote files out.
... but it was still working by serializing and deserializing the entire
dict, swapping out its guts with the newly-serialized copy in an invasive
and horrible fashion that coupled ctf_serialize() to almost every field in
the ctf_dict_t. This is totally useless, and fixing it is easy: just rip
all that code out and have ctf_serialize return a serialized representation,
and let everything use that directly. This simplifies most of its callers
significantly.
(It also points up another bug: ctf_gzwrite() failed to call ctf_serialize()
at all, so it would only ever work for a dict you just ctf_write_mem()ed
yourself, just for its invisible side-effect of serializing the dict!)
This lets us simplify away a bunch of internal-only open-side functionality
for overriding the syn_ext_strtab and some just-added functionality for
forcing in an existing atoms table, without loss of functionality, and lets
us lift the restriction on reserializing a dict that was ctf_open()ed rather
than being ctf_create()d: it's now perfectly OK to open a dict, modify it
(except for adding members to existing structs, unions, or enums, which
fails with -ECTF_RDONLY), and write it out again, just as one would expect.
libctf/
* ctf-serialize.c (ctf_symtypetab_sect_sizes): Fix typos.
(ctf_type_sect_size): Add static type sizes too.
(ctf_serialize): Return the new dict rather than updating the
existing dict. No longer fail for dicts with static types;
copy them onto the start of the new types table.
(ctf_gzwrite): Actually serialize before gzwriting.
(ctf_write_mem): Improve forced (test-mode) endian-flipping:
flip dicts even if they are too small to be compressed.
Improve confusing variable naming.
* ctf-archive.c (arc_write_one_ctf): Don't bother to call
ctf_serialize: both the functions we call do so.
* ctf-string.c (ctf_str_create_atoms): Drop serializing case
(atoms arg).
* ctf-open.c (ctf_simple_open): Call ctf_bufopen directly.
(ctf_simple_open_internal): Delete.
(ctf_bufopen_internal): Delete/rename to ctf_bufopen: no
longer bother with syn_ext_strtab or forced atoms table,
serialization no longer needs them.
* ctf-create.c (ctf_create): Call ctf_bufopen directly.
* ctf-impl.h (ctf_str_create_atoms): Drop atoms arg.
(ctf_simple_open_internal): Delete.
(ctf_bufopen_internal): Likewise.
(ctf_serialize): Adjust.
* testsuite/libctf-lookup/add-to-opened.c: Adjust now that
this is supposed to work.
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This commit finally adjusts strtab writeout so that repeated writeouts, or
writeouts of a dict that was read in earlier, only sorts the portion of the
strtab that was newly added.
There are three intertwined changes here:
- pull the contents of strtabs from newly ctf_bufopened dicts into the
atoms table, so that future additions will reuse the existing offset etc
rather than adding new identical strings
- allow the internal ctf_bufopen done by serialization to contribute its
existing atoms table, so that existing atoms can be used for the
remainder of the open process (like name table construction): this atoms
table currente gets thrown away in the mass reassignment done later in
ctf_serialize in any case, but it needs to be there during the open.
- rewrite ctf_str_write_strtab so that a) it uses iterators rather than
ctf_*_iter, reducing pointless structures which serve no other purpose
than to implement ordinary variable scope, but more clunkily, and b)
retains the existing strtab on the front of the new one, with its sort
retained, rather than resorting, so all existing already-written strtab
offsets remain valid across the call.
This latter change finally permits repeated serializations, and
reserializations of ctf_open()ed dicts, to work, but for now we keep the
code that prevents that because serialization is about to change again in a
way that will make it more obvious that doing such things is safe, and we
can take it out then.
(There are also some smaller changes like moving the purge of the refs table
into ctf_str_write_strtab(), since that's where the changes happen that
invalidate it, rather than doing it in ctf_serialize(). We also prohibit
something that has never worked, opening a dict and then reporting symbols
to it via ctf_link_add_strtab() et al: you must do that to newly-created
dicts which have had stuff ctf_link()ed into them. This is very unlikely
ever to be a problem in practice: linkers just don't do that sort of thing.)
libctf/
* ctf-create.c (ctf_create): Add (temporary) atoms arg.
* ctf-impl.h (struct ctf_dict.ctf_dynstrtab): New.
(ctf_str_create_atoms): Adjust.
(ctf_str_write_strtab): Likewise.
(ctf_simple_open_internal): Likewise.
* ctf-open.c (ctf_simple_open_internal): Add atoms arg.
(ctf_bufopen): Likewise.
(ctf_bufopen_internal): Initialize just enough of an
atoms table: pre-init from the atoms arg if supplied.
(ctf_simple_open): Adjust.
* ctf-serialize.c (ctf_serialize): Constify the strtab.
Move ref list purging into ctf_str_write_strtab.
Initialize the new dict with the old dict's atoms table.
Accept the new strtab from ctf_str_write_strtab.
Adjust for addition of ctf_dynstrtab.
* ctf-string.c (ctf_strraw_explicit): Improve comments.
(ctf_str_create_atoms): Prepopulate from an existing atoms table,
or alternatively pull in all strings from the strtab and turn
them into atoms.
(ctf_str_free_atoms): Free the dynstrtab and its strtab.
(struct ctf_strtab_write_state): Remove.
(ctf_str_count_strtab): Fold this...
(ctf_str_populate_sorttab): ... and this...
(ctf_str_write_strtab): ... into this. Prepend existing strings
to the strtab rather than resorting them (and wrecking their
offsets). Keep the dynstrtab updated. Update refs for all
atoms with refs, whether or not they are strings newly added
to the strtab.
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A few years ago we introduced a 'pending refs' abstraction to fix one
problem: serializing a dict, then changing it would tend to corrupt the dict
because the strtab sort we do on strtab writeout (to improve compression
efficiency) would modify the offset of any strings that sorted
lexicographically earlier in the strtab: so we added a new restriction that
all strings are added only at serialization time, and maintained a set of
'pending' refs that were added earlier, whose offsets we could update (like
other refs) at writeout time.
This was in hindsight seriously problematic for maintenance (because
serialization has to traverse all strings in all datatypes in the entire
dict), and has become impossible to sustain now that we can read in existing
dicts, modify them, and reserialize them again. We really don't want to
have to dig through the entire dict we jut read in just in order to dig out
all its strtab offsets, then *change* it, just for the sake of a sort that
adds a frankly trivial amount of compression efficiency.
Sorting *is* still worthwhile -- but it sacrifices very little to only sort
newly-added portions of the strtab, reusing older portions as necessary.
As a first stage in this, discard the whole "pending refs" abstraction and
replace it with "movable" refs, which are exactly like all other refs
(addresses containing the strtab offset of some string, which are updated
wiht the final strtab offset on serialization) except that we track them in
a reverse dict so that we can move the refs around (which we do whenever we
realloc() a buffer containing a bunch of structure members or something when
we add members to the structure).
libctf/
* ctf-create.c (ctf_add_enumerator): Call ctf_str_move_refs; add
a movable ref.
(ctf_add_member_offset): Likewise.
* ctf-util.c (ctf_realloc): Delete.
* ctf-serialize.c (ctf_serialize): No longer use it. Adjust to
new fields.
* ctf-string.c (ctf_str_purge_atom_refs): Purge movable refs.
(ctf_str_free_atom): Free freeable atoms' strings.
(ctf_str_create_atoms): Create the movable refs dynhash if needed.
(ctf_str_free_atoms): Destroy it.
(CTF_STR_MOVABLE): Switch (back) from ints to flags (see previous
reversion). Add new flag.
(aref_create): New, populate movable refs if need be.
(ctf_str_add_ref_internal): Switch back to flags, update refs
directly for nonprovisional strings (with already-known fixed offsets);
create refs via aref_create. Allocate strings only if not within an
mmapped strtab.
(ctf_str_add_movable_ref): New.
(ctf_str_add): Adjust to CTF_STR_* reintroduction.
(ctf_str_add_external): LIkewise.
(ctf_str_move_refs): New, move refs via ctf_str_movable_refs
backpointer.
(ctf_str_purge_refs): Drop ctf_str_num_refs.
(ctf_str_update_refs): Fix indentation.
* ctf-impl.h (struct ctf_str_atom_movable): New.
(struct ctf_dict.ctf_str_num_refs): Drop.
(struct ctf_dict.ctf_str_movable_refs): New.
(ctf_str_add_movable_ref): Declare.
(ctf_str_move_refs): Likewise.
(ctf_realloc): Drop.
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This reverts commit 986e9e3aa03f854bedacef7fac38fe8f009a416c.
(We do not revert the testcase -- it remains valid -- but we are
taking a different, less complex and more robust approach.)
This also deletes the pending refs abstraction without (yet)
replacing it, so some tests will fail for a commit or two.
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These two fields are constantly confusing because CTF dicts contain both
a symtypetab and strtab, but these fields are not that: they are the
symtab and strtab from the ELF file. We have enough string tables now
(internal, external, synthetic external, dynamic) that we need to at
least name them better than this to avoid getting totally confused.
Rename them to ctf_ext_symtab and ctf_ext_strtab.
libctf/
* ctf-dump.c (ctf_dump_objts): Rename ctf_symtab -> ctf_ext_symtab.
* ctf-impl.h (struct ctf_dict.ctf_symtab): Rename to...
(struct ctf_dict.ctf_ext_strtab): ... this.
(struct ctf_dict.ctf_strtab): Rename to...
(struct ctf_dict.ctf_ext_strtab): ... this.
* ctf-lookup.c (ctf_lookup_symbol_name): Adapt.
(ctf_lookup_symbol_idx): Adapt.
(ctf_lookup_by_sym_or_name): Adapt.
* ctf-open.c (ctf_bufopen_internal): Adapt.
(ctf_dict_close): Adapt.
(ctf_getsymsect): Adapt.
(ctf_getstrsect): Adapt.
(ctf_symsect_endianness): Adapt.
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ctf_update has been called ctf_serialize for years now.
libctf/
* ctf-impl.h: Fix comment typo.
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This flag was meant as an optimization to avoid reserializing dicts
unnecessarily. It was critically necessary back when serialization was
done by ctf_update() and you had to call that every time you wanted any
new modifications to the type table to be usable by other types, but
that has been unnecessary for years now, and serialization is only done
once when writing out, which one would naturally assume would always
serialize the dict. Worse, it never really worked: it only tracked
newly-added types, not things like added symbols which might equally
well require reserialization, and it gets in the way of an upcoming
change. Delete entirely.
libctf/
* ctf-create.c (ctf_create): Drop LCTF_DIRTY.
(ctf_discard): Likewise.
(ctf_rollback): Likewise.
(ctf_add_generic): Likewise.
(ctf_set_array): Likewise.
(ctf_add_enumerator): Likewise.
(ctf_add_member_offset): Likewise.
(ctf_add_variable_forced): Likewise.
* ctf-link.c (ctf_link_intern_extern_string): Likewise.
(ctf_link_add_strtab): Likewise.
* ctf-serialize.c (ctf_serialize): Likewise.
* ctf-impl.h (LCTF_DIRTY): Likewise.
(LCTF_LINKING): Renumber.
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libctf has long declared deserialized dictionaries (out of files or ELF
sections or memory buffers or whatever) to be read-only: back in the
furthest prehistory this was not the case, in that you could add a
few sorts of type to such dicts, but attempting to do so often caused
horrible memory corruption, so I banned the lot.
But it turns out real consumers want it (notably DTrace, which
synthesises pointers to types that don't have them and adds them to the
ctf_open()ed dicts if it needs them). Let's bring it back again, but
without the memory corruption and without the massive code duplication
required in days of yore to distinguish between static and dynamic
types: the representation of both types has been identical for a few
years, with the only difference being that types as a whole are stored in
a big buffer for types read in via ctf_open and per-type hashtables for
newly-added types.
So we discard the internally-visible concept of "readonly dictionaries"
in favour of declaring the *range of types* that were already present
when the dict was read in to be read-only: you can't modify them (say,
by adding members to them if they're structs, or calling ctf_set_array
on them), but you can add more types and point to them. (The API
remains the same, with calls sometimes returning ECTF_RDONLY, but now
they do so less often.)
This is a fairly invasive change, mostly because code written since the
ban was introduced didn't take the possibility of a static/dynamic split
into account. Some of these irregularities were hard to define as
anything but bugs.
Notably:
- The symbol handling was assuming that symbols only needed to be
looked for in dynamic hashtabs or static linker-laid-out indexed/
nonindexed layouts, but now we want to check both in case people
added more symbols to a dict they opened.
- The code that handles type additions wasn't checking to see if types
with the same name existed *at all* (so you could do
ctf_add_typedef (fp, "foo", bar) repeatedly without error). This
seems reasonable for types you just added, but we probably *do* want
to ban addition of types with names that override names we already
used in the ctf_open()ed portion, since that would probably corrupt
existing type relationships. (Doing things this way also avoids
causing new errors for any existing code that was doing this sort of
thing.)
- ctf_lookup_variable entirely failed to work for variables just added
by ctf_add_variable: you had to write the dict out and read it back
in again before they appeared.
- The symbol handling remembered what symbols you looked up but didn't
remember their types, so you could look up an object symbol and then
find it popping up when you asked for function symbols, which seems
less than ideal. Since we had to rejig things enough to be able to
distinguish function and object symbols internally anyway (in order
to give suitable errors if you try to add a symbol with a name that
already existed in the ctf_open()ed dict), this bug suddenly became
more visible and was easily fixed.
We do not (yet) support writing out dicts that have been previously read
in via ctf_open() or other deserializer (you can look things up in them,
but not write them out a second time). This never worked, so there is
no incompatibility; if it is needed at a later date, the serializer is a
little bit closer to having it work now (the only table we don't deal
with is the types table, and that's because the upcoming CTFv4 changes
are likely to make major changes to the way that table is represented
internally, so adding more code that depends on its current form seems
like a bad idea).
There is a new testcase that tests much of this, in particular that
modification of existing types is still banned and that you can add new
ones and chase them without error.
libctf/
* ctf-impl.h (struct ctf_dict.ctf_symhash): Split into...
(ctf_dict.ctf_symhash_func): ... this and...
(ctf_dict.ctf_symhash_objt): ... this.
(ctf_dict.ctf_stypes): New, counts static types.
(LCTF_INDEX_TO_TYPEPTR): Use it instead of CTF_RDWR.
(LCTF_RDWR): Deleted.
(LCTF_DIRTY): Renumbered.
(LCTF_LINKING): Likewise.
(ctf_lookup_variable_here): New.
(ctf_lookup_by_sym_or_name): Likewise.
(ctf_symbol_next_static): Likewise.
(ctf_add_variable_forced): Likewise.
(ctf_add_funcobjt_sym_forced): Likewise.
(ctf_simple_open_internal): Adjust.
(ctf_bufopen_internal): Likewise.
* ctf-create.c (ctf_grow_ptrtab): Adjust a lot to start with.
(ctf_create): Migrate a bunch of initializations into bufopen.
Force recreation of name tables. Do not forcibly override the
model, let ctf_bufopen do it.
(ctf_static_type): New.
(ctf_update): Drop LCTF_RDWR check.
(ctf_dynamic_type): Likewise.
(ctf_add_function): Likewise.
(ctf_add_type_internal): Likewise.
(ctf_rollback): Check ctf_stypes, not LCTF_RDWR.
(ctf_set_array): Likewise.
(ctf_add_struct_sized): Likewise.
(ctf_add_union_sized): Likewise.
(ctf_add_enum): Likewise.
(ctf_add_enumerator): Likewise (only on the target dict).
(ctf_add_member_offset): Likewise.
(ctf_add_generic): Drop LCTF_RDWR check. Ban addition of types
with colliding names.
(ctf_add_forward): Note safety under the new rules.
(ctf_add_variable): Split all but the existence check into...
(ctf_add_variable_forced): ... this new function.
(ctf_add_funcobjt_sym): Likewise...
(ctf_add_funcobjt_sym_forced): ... for this new function.
* ctf-link.c (ctf_link_add_linker_symbol): Ban calling on dicts
with any stypes.
(ctf_link_add_strtab): Likewise.
(ctf_link_shuffle_syms): Likewise.
(ctf_link_intern_extern_string): Note pre-existing prohibition.
* ctf-lookup.c (ctf_lookup_by_id): Drop LCTF_RDWR check.
(ctf_lookup_variable): Split out looking in a dict but not
its parent into...
(ctf_lookup_variable_here): ... this new function.
(ctf_lookup_symbol_idx): Track whether looking up a function or
object: cache them separately.
(ctf_symbol_next): Split out looking in non-dynamic symtypetab
entries to...
(ctf_symbol_next_static): ... this new function. Don't get confused
by the simultaneous presence of static and dynamic symtypetab entries.
(ctf_try_lookup_indexed): Don't waste time looking up symbols by
index before there can be any idea how symbols are numbered.
(ctf_lookup_by_sym_or_name): Distinguish between function and
data object lookups. Drop LCTF_RDWR.
(ctf_lookup_by_symbol): Adjust.
(ctf_lookup_by_symbol_name): Likewise.
* ctf-open.c (init_types): Rename to...
(init_static_types): ... this. Drop LCTF_RDWR. Populate ctf_stypes.
(ctf_simple_open): Drop writable arg.
(ctf_simple_open_internal): Likewise.
(ctf_bufopen): Likewise.
(ctf_bufopen_internal): Populate fields only used for writable dicts.
Drop LCTF_RDWR.
(ctf_dict_close): Cater for symhash cache split.
* ctf-serialize.c (ctf_serialize): Use ctf_stypes, not LCTF_RDWR.
* ctf-types.c (ctf_variable_next): Drop LCTF_RDWR.
* testsuite/libctf-lookup/add-to-opened*: New test.
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libctf internally maintains a set of hash tables for type name lookups,
one for each valid C type namespace (struct, union, enum, and everything
else).
Or, rather, it maintains *two* sets of hash tables: one, a ctf_hash *,
is meant for lookups in ctf_(buf)open()ed dicts with fixed content; the
other, a ctf_dynhash *, is meant for lookups in ctf_create()d dicts.
This distinction was somewhat valuable in the far pre-binutils past when
two different hashtable implementations were used (one expanding, the
other fixed-size), but those days are long gone: the hash table
implementations are almost identical, both wrappers around the libiberty
hashtab. The ctf_dynhash has many more capabilities than the ctf_hash
(iteration, deletion, etc etc) and has no downsides other than starting
at a fixed, arbitrary small size.
That limitation is easy to lift (via a new ctf_dynhash_create_sized()),
following which we can throw away nearly all the ctf_hash
implementation, and all the code to choose between readable and writable
hashtabs; the few convenience functions that are still useful (for
insertion of name -> type mappings) can also be generalized a bit so
that the extra string verification they do is potentially available to
other string lookups as well.
(libctf still has two hashtable implementations, ctf_dynhash, above,
and ctf_dynset, which is a key-only hashtab that can avoid a great many
malloc()s, used for high-volume applications in the deduplicator.)
libctf/
* ctf-create.c (ctf_create): Eliminate ctn_writable.
(ctf_dtd_insert): Likewise.
(ctf_dtd_delete): Likewise.
(ctf_rollback): Likewise.
(ctf_name_table): Eliminate ctf_names_t.
* ctf-hash.c (ctf_dynhash_create): Comment update.
Reimplement in terms of...
(ctf_dynhash_create_sized): ... this new function.
(ctf_hash_create): Remove.
(ctf_hash_size): Remove.
(ctf_hash_define_type): Remove.
(ctf_hash_destroy): Remove.
(ctf_hash_lookup_type): Rename to...
(ctf_dynhash_lookup_type): ... this.
(ctf_hash_insert_type): Rename to...
(ctf_dynhash_insert_type): ... this, moving validation to...
* ctf-string.c (ctf_strptr_validate): ... this new function.
* ctf-impl.h (struct ctf_names): Extirpate.
(struct ctf_lookup.ctl_hash): Now a ctf_dynhash_t.
(struct ctf_dict): All ctf_names_t fields are now ctf_dynhash_t.
(ctf_name_table): Now returns a ctf_dynhash_t.
(ctf_lookup_by_rawhash): Remove.
(ctf_hash_create): Likewise.
(ctf_hash_insert_type): Likewise.
(ctf_hash_define_type): Likewise.
(ctf_hash_lookup_type): Likewise.
(ctf_hash_size): Likewise.
(ctf_hash_destroy): Likewise.
(ctf_dynhash_create_sized): New.
(ctf_dynhash_insert_type): New.
(ctf_dynhash_lookup_type): New.
(ctf_strptr_validate): New.
* ctf-lookup.c (ctf_lookup_by_name_internal): Adapt.
* ctf-open.c (init_types): Adapt.
(ctf_set_ctl_hashes): Adapt.
(ctf_dict_close): Adapt.
* ctf-serialize.c (ctf_serialize): Adapt.
* ctf-types.c (ctf_lookup_by_rawhash): Remove.
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Adds two new external authors to etc/update-copyright.py to cover
bfd/ax_tls.m4, and adds gprofng to dirs handled automatically, then
updates copyright messages as follows:
1) Update cgen/utils.scm emitted copyrights.
2) Run "etc/update-copyright.py --this-year" with an extra external
author I haven't committed, 'Kalray SA.', to cover gas testsuite
files (which should have their copyright message removed).
3) Build with --enable-maintainer-mode --enable-cgen-maint=yes.
4) Check out */po/*.pot which we don't update frequently.
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Made sure there is no implicit conversion between signed and unsigned
return value for functions setting the ctf_errno value.
An example of the problem is that in ctf_member_next, the "offset" value
is either 0L or (ctf_id_t)-1L, but it should have been 0L or -1L.
The issue was discovered while building a 64 bit ld binary to be
executed on the Windows platform.
Example object file that demonstrates the issue is attached in the PR.
libctf/
Affected functions adjusted.
Signed-off-by: Torbjörn SVENSSON <torbjorn.svensson@foss.st.com>
Co-Authored-By: Yvan ROUX <yvan.roux@foss.st.com>
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The newer update-copyright.py fixes file encoding too, removing cr/lf
on binutils/bfdtest2.c and ld/testsuite/ld-cygwin/exe-export.exp, and
embedded cr in binutils/testsuite/binutils-all/ar.exp string match.
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Right now, if you compile the same .c input repeatedly with CTF enabled
and different compilation flags, then arrange to link all of these
together, then things misbehave in various ways. libctf may conflate
either inputs (if the .o files have the same name, say if they are
stored in different .a archives), or per-CU outputs when conflicting
types are found: the latter can lead to entirely spurious errors when
it tries to produce multiple per-CU outputs with the same name
(discarding all but the last, but then looking for types in the earlier
ones which have just been thrown away).
Fixing this is multi-pronged. Both inputs and outputs need to be
differentiated in the hashtables libctf keeps them in: inputs with the
same cuname and filename need to be considered distinct as long as they
have different associated CTF dicts, and per-CU outputs need to be
considered distinct as long as they have different associated input
dicts. Right now there is nothing tying the two together other than the
CU name: fix this by introducing a new field in the ctf_dict_t named
ctf_link_in_out, which (for input dicts) points to the associated per-CU
output dict (if any), and for output dicts points to the associated
input dict. At creation time the name used is completely arbitrary:
it's only important that it be distinct if CTF dicts are distinct. So,
when a clash is found, adjust the CU name by sticking the number of
elements in the input on the end. At output time, the CU name will
appear in the linked object, so it matters a little more that it look
slightly less ugly: in conflicting cases, append an incrementing
integer, starting at 0.
This naming scheme is not very helpful, but it's hard to see what else
we can do. The input .o name may be the same. The input .a name is not
even visible to ctf_link, and even *that* might be the same, because
.a's can contain many members with the same name, all of which
participate in the link. All we really know is that the two have
distinct dictionaries with distinct types in them, and at least this way
they are all represented, any any symbols, variables etc referring to
those types are accurately stored.
(As a side-effect this also fixes a use-after-free and double-free when
errors are found during variable or symbol emission.)
Use the opportunity to prevent a couple of sources of problems, to wit
changing the active CU mappings when a link has already been done
(no effect on ld, which doesn't use CU mappings at all), and causing
multiple consecutive ctf_link's to have the same net effect as just
doing the last one (no effect on ld, which only ever does one
ctf_link) rather than having the links be a sort of half-incremental
not-really-intended mess.
libctf/ChangeLog:
PR libctf/29242
* ctf-impl.h (struct ctf_dict) [ctf_link_in_out]: New.
* ctf-dedup.c (ctf_dedup_emit_type): Set it.
* ctf-link.c (ctf_link_add_ctf_internal): Set the input
CU name uniquely when clashes are found.
(ctf_link_add): Document what repeated additions do.
(ctf_new_per_cu_name): New, come up with a consistent
name for a new per-CU dict.
(ctf_link_deduplicating): Use it.
(ctf_create_per_cu): Use it, and ctf_link_in_out, and set
ctf_link_in_out properly. Don't overwrite per-CU dicts with
per-CU dicts relating to different inputs.
(ctf_link_add_cu_mapping): Prevent per-CU mappings being set up
if we already have per-CU outputs.
(ctf_link_one_variable): Adjust ctf_link_per_cu call.
(ctf_link_deduplicating_one_symtypetab): Likewise.
(ctf_link_empty_outputs): New, delete all the ctf_link_outputs
and blank out ctf_link_in_out on the corresponding inputs.
(ctf_link): Clarify the effect of multiple ctf_link calls.
Empty ctf_link_outputs if it already exists rather than
having the old output leak into the new link. Fix a variable
name.
* testsuite/config/default.exp (AR): Add.
(OBJDUMP): Likewise.
* testsuite/libctf-regression/libctf-repeat-cu.exp: New test.
* testsuite/libctf-regression/libctf-repeat-cu*: Main program,
library, and expected results for the test.
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libctf has always handled endianness differences by detecting
foreign-endian CTF dicts on the input and endian-flipping them: dicts
are always written in native endianness. This makes endian-awareness
very low overhead, but it means that the foreign-endian code paths
almost never get routinely tested, since "make check" usually reads in
dicts ld has just written out: only a few corrupted-CTF tests are
actually in fixed endianness, and even they only test the foreign-
endian code paths when you run make check on a big-endian machine.
(And the fix is surely not to add more .s-based tests like that, because
they are a nightmare to maintain compared to the C-code-based ones.)
To improve on this, add a new environment variable,
LIBCTF_WRITE_FOREIGN_ENDIAN, which causes libctf to unconditionally
endian-flip at ctf_write time, so the output is always in the wrong
endianness. This then tests the foreign-endian read paths properly
at open time.
Make this easier by restructuring the writeout code in ctf-serialize.c,
which duplicates the maybe-gzip-and-write-out code three times (once
for ctf_write_mem, with thresholding, and once each for
ctf_compress_write and ctf_write just so those can avoid thresholding
and/or compression). Instead, have the latter two call the former
with thresholds of 0 or (size_t) -1, respectively.
The endian-flipping code itself gains a bit of complexity, because
one single endian-flipper (flip_types) was assuming the input to be
in foreign-endian form and assuming it could pull things out of the
input once they had been flipped and make sense of them. At the
cost of a few lines of duplicated initializations, teach it to
read before flipping if we're flipping to foreign-endianness instead
of away from it.
libctf/
* ctf-impl.h (ctf_flip_header): No longer static.
(ctf_flip): Likewise.
* ctf-open.c (flip_header): Rename to...
(ctf_flip_header): ... this, now it is not private to one file.
(flip_ctf): Rename...
(ctf_flip): ... this too. Add FOREIGN_ENDIAN arg.
(flip_types): Likewise. Use it.
(ctf_bufopen_internal): Adjust calls.
* ctf-serialize.c (ctf_write_mem): Add flip_endian path via
a newly-allocated bounce buffer.
(ctf_compress_write): Move below ctf_write_mem and reimplement
in terms of it.
(ctf_write): Likewise.
(ctf_gzwrite): Note that this obscure writeout function does not
support endian-flipping.
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The result of running etc/update-copyright.py --this-year, fixing all
the files whose mode is changed by the script, plus a build with
--enable-maintainer-mode --enable-cgen-maint=yes, then checking
out */po/*.pot which we don't update frequently.
The copy of cgen was with commit d1dd5fcc38ead reverted as that commit
breaks building of bfp opcodes files.
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* ctf-impl.h (ctf_dynset_eq_string): Don't declare.
* ctf-hash.c (ctf_dynset_eq_string): Delete function.
* ctf-dedup.c (make_set_element): Use htab_eq_string.
(ctf_dedup_atoms_init, ADD_CITER, ctf_dedup_init): Likewise.
(ctf_dedup_conflictify_unshared): Likewise.
(ctf_dedup_walk_output_mapping): Likewise.
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bfd/
* bfd-in.h (startswith): New inline.
(CONST_STRNEQ): Use startswith.
* bfd-in2.h: Regenerate.
gdbsupport/
* common-utils.h (startswith): Delete version now supplied by bfd.h.
libctf/
* ctf-impl.h: Include string.h.
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This completes the job of unifying what was once three separate code
paths full of duplication for every function dealing with querying the
properties of struct and union members. The dynamic code path was
already removed: this change removes the distinction between small and
large members, by adding a helper that copies out members from the vlen,
expanding small members into large ones as it does so.
This makes it possible to have *more* representations of things like
structure members without needing to change the querying functions at
all. It also lets us check for buffer overruns more effectively,
verifying that we don't accidentally overrun the end of the vlen in
either the dynamic or static type case.
libctf/ChangeLog
2021-03-18 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (ctf_next_t) <ctn_tp>: New.
<u.ctn_mp>: Remove.
<u.ctn_lmp>: Remove.
<u.ctn_vlen>: New.
* ctf-types.c (ctf_struct_member): New.
(ctf_member_next): Use it, dropping separate large/small code paths.
(ctf_type_align): Likewise.
(ctf_member_info): Likewise.
(ctf_type_rvisit): Likewise.
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Eliminate the dynamic member storage for structs and unions as we have
for other dynamic types. This is much like the previous enum
elimination, except that structs and unions are the only types for which
a full-sized ctf_type_t might be needed. Up to now, this decision has
been made in the individual ctf_add_{struct,union}_sized functions and
duplicated in ctf_add_member_offset. The vlen machinery lets us
simplify this, always allocating a ctf_lmember_t and setting the
dtd_data's ctt_size to CTF_LSIZE_SENT: we figure out whether this is
really justified and (almost always) repack things down into a
ctf_stype_t at ctf_serialize time.
This allows us to eliminate the dynamic member paths from the iterators and
query functions in ctf-types.c in favour of always using the large-structure
vlen stuff for dynamic types (the diff is ugly but that's just because of the
volume of reindentation this calls for). This also means the large-structure
vlen stuff gets more heavily tested, which is nice because it was an almost
totally unused code path before now (it only kicked in for structures of size
>4GiB, and how often do you see those?)
The only extra complexity here is ctf_add_type. Back in the days of the
nondeduplicating linker this was called a ridiculous number of times for
countless identical copies of structures: eschewing the repeated lookups of the
dtd in ctf_add_member_offset and adding the members directly saved an amazing
amount of time. Now the nondeduplicating linker is gone, this is extreme
overoptimization: we can rip out the direct addition and use ctf_member_next and
ctf_add_member_offset, just like ctf_dedup_emit does.
We augment a ctf_add_type test to try adding a self-referential struct, the only
thing the ctf_add_type part of this change really perturbs.
This completes the elimination of dtd_u.
libctf/ChangeLog
2021-03-18 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (ctf_dtdef_t) <dtu_members>: Remove.
<dtd_u>: Likewise.
(ctf_dmdef_t): Remove.
(struct ctf_next) <u.ctn_dmd>: Remove.
* ctf-create.c (INITIAL_VLEN): New, more-or-less arbitrary initial
vlen size.
(ctf_add_enum): Use it.
(ctf_dtd_delete): Do not free the (removed) dmd; remove string
refs from the vlen on struct deletion.
(ctf_add_struct_sized): Populate the vlen: do it by hand if
promoting forwards. Always populate the full-size
lsizehi/lsizelo members.
(ctf_add_union_sized): Likewise.
(ctf_add_member_offset): Set up the vlen rather than the dmd.
Expand it as needed, repointing string refs via
ctf_str_move_pending. Add the member names as pending strings.
Always populate the full-size lsizehi/lsizelo members.
(membadd): Remove, folding back into...
(ctf_add_type_internal): ... here, adding via an ordinary
ctf_add_struct_sized and _next iteration rather than doing
everything by hand.
* ctf-serialize.c (ctf_copy_smembers): Remove this...
(ctf_copy_lmembers): ... and this...
(ctf_emit_type_sect): ... folding into here. Figure out if a
ctf_stype_t is needed here, not in ctf_add_*_sized.
(ctf_type_sect_size): Figure out the ctf_stype_t stuff the same
way here.
* ctf-types.c (ctf_member_next): Remove the dmd path and always
use the vlen. Force large-structure usage for dynamic types.
(ctf_type_align): Likewise.
(ctf_member_info): Likewise.
(ctf_type_rvisit): Likewise.
* testsuite/libctf-regression/type-add-unnamed-struct-ctf.c: Add a
self-referential type to this test.
* testsuite/libctf-regression/type-add-unnamed-struct.c: Adjusted
accordingly.
* testsuite/libctf-regression/type-add-unnamed-struct.lk: Likewise.
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This is the first tricky one, the first complex multi-entry vlen
containing strings. To handle this in vlen form, we have to handle
pending refs moving around on realloc.
We grow vlen regions using a new ctf_grow_vlen function, and iterate
through the existing enums every time a grow happens, telling the string
machinery the distance between the old and new vlen region and letting
it adjust the pending refs accordingly. (This avoids traversing all
outstanding refs to find the refs that need adjusting, at the cost of
having to traverse one enum: an obvious major performance win.)
Addition of enums themselves (and also structs/unions later) is a bit
trickier than earlier forms, because the type might be being promoted
from a forward, and forwards have no vlen: so we have to spot that and
create it if needed.
Serialization of enums simplifies down to just telling the string
machinery about the string refs; all the enum type-lookup code loses all
its dynamic member lookup complexity entirely.
A new test is added that iterates over (and gets values of) an enum with
enough members to force a round of vlen growth.
libctf/ChangeLog
2021-03-18 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (ctf_dtdef_t) <dtd_vlen_alloc>: New.
(ctf_str_move_pending): Declare.
* ctf-string.c (ctf_str_add_ref_internal): Fix error return.
(ctf_str_move_pending): New.
* ctf-create.c (ctf_grow_vlen): New.
(ctf_dtd_delete): Zero out the vlen_alloc after free. Free the
vlen later: iterate over it and free enum name refs first.
(ctf_add_generic): Populate dtd_vlen_alloc from vlen.
(ctf_add_enum): populate the vlen; do it by hand if promoting
forwards.
(ctf_add_enumerator): Set up the vlen rather than the dmd. Expand
it as needed, repointing string refs via ctf_str_move_pending. Add
the enumerand names as pending strings.
* ctf-serialize.c (ctf_copy_emembers): Remove.
(ctf_emit_type_sect): Copy the vlen into place and ref the
strings.
* ctf-types.c (ctf_enum_next): The dynamic portion now uses
the same code as the non-dynamic.
(ctf_enum_name): Likewise.
(ctf_enum_value): Likewise.
* testsuite/libctf-lookup/enum-many-ctf.c: New test.
* testsuite/libctf-lookup/enum-many.lk: New test.
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The preceding change revealed a new bug: the string table is sorted for
better compression, so repeated serialization with type (or member)
additions in the middle can move strings around. But every
serialization flushes the set of refs (the memory locations that are
automatically updated with a final string offset when the strtab is
updated), so if we are not to have string offsets go stale, we must do
all ref additions within the serialization code (which walks the
complete set of types and symbols anyway). Unfortunately, we were adding
one ref in another place: the type name in the dynamic type definitions,
which has a ref added to it by ctf_add_generic.
So adding a type, serializing (via, say, one of the ctf_write
functions), adding another type with a name that sorts earlier, and
serializing again will corrupt the name of the first type because it no
longer had a ref pointing to its dtd entry's name when its string offset
was shifted later in the strtab to mae way for the other type.
To ensure that we don't miss strings, we also maintain a set of *pending
refs* that will be added later (during serialization), and remove
entries from that set when the ref is finally added. We always use
ctf_str_add_pending outside ctf-serialize.c, ensure that ctf_serialize
adds all strtab offsets as refs (even those in the dtds) on every
serialization, and mandate that no refs are live on entry to
ctf_serialize and that all pending refs are gone before strtab
finalization. (Of necessity ctf_serialize has to traverse all strtab
offsets in the dtds in order to serialize them, so adding them as refs
at the same time is easy.)
(Note that we still can't erase unused atoms when we roll back, though
we can erase unused refs: members and enums are still not removed by
rollbacks and might reference strings added after the snapshot.)
libctf/ChangeLog
2021-03-18 Nick Alcock <nick.alcock@oracle.com>
* ctf-hash.c (ctf_dynset_elements): New.
* ctf-impl.h (ctf_dynset_elements): Declare it.
(ctf_str_add_pending): Likewise.
(ctf_dict_t) <ctf_str_pending_ref>: New, set of refs that must be
added during serialization.
* ctf-string.c (ctf_str_create_atoms): Initialize it.
(CTF_STR_ADD_REF): New flag.
(CTF_STR_MAKE_PROVISIONAL): Likewise.
(CTF_STR_PENDING_REF): Likewise.
(ctf_str_add_ref_internal): Take a flags word rather than int
params. Populate, and clear out, ctf_str_pending_ref.
(ctf_str_add): Adjust accordingly.
(ctf_str_add_external): Likewise.
(ctf_str_add_pending): New.
(ctf_str_remove_ref): Also remove the potential ref if it is a
pending ref.
* ctf-serialize.c (ctf_serialize): Prohibit addition of strings
with ctf_str_add_ref before serialization. Ensure that the
ctf_str_pending_ref set is empty before strtab finalization.
(ctf_emit_type_sect): Add a ref to the ctt_name.
* ctf-create.c (ctf_add_generic): Add the ctt_name as a pending
ref.
* testsuite/libctf-writable/reserialize-strtab-corruption.*: New test.
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One more member vanishes from the dtd_u, leaving only the member for
struct/union/enum members.
There's not much to do here, since as of commit afd78bd6f0a30ba5 we use
the same representation (type sizes, etc) in the dtu_argv as we will
use in the final vlen, with one exception: the vlen has alignment
padding, and the dtu_argv did not. Simplify things by adding suitable
padding in both cases.
libctf/ChangeLog
2021-03-18 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (ctf_dtdef_t) <dtd_u.dtu_argv>: Remove.
* ctf-create.c (ctf_dtd_delete): No longer free it.
(ctf_add_function): Use the dtd_vlen, not dtu_argv. Properly align.
* ctf-serialize.c (ctf_emit_type_sect): Just copy the dtd_vlen.
* ctf-types.c (ctf_func_type_info): Just use the vlen.
(ctf_func_type_args): Likewise.
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This is even simpler than ints, floats and slices, with the only extra
complication being the need to manually transfer the array parameter in
the rarely-used function ctf_set_array. (Arrays are unique in libctf in
that they can be modified post facto, not just created and appended to.
I'm not sure why they got this exemption, but it's easy to maintain.)
libctf/ChangeLog
2021-03-18 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (ctf_dtdef_t) <dtd_u.dtu_arr>: Remove.
* ctf-create.c (ctf_add_array): Use the dtd_vlen, not dtu_arr.
(ctf_set_array): Likewise.
* ctf-serialize.c (ctf_emit_type_sect): Just copy the dtd_vlen.
* ctf-types.c (ctf_array_info): Just use the vlen.
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This series eliminates a lot of special-case code to handle dynamic
types (types added to writable dicts and not yet serialized).
Historically, when such types have variable-length data in their final
CTF representations, libctf has always worked by adding such types to a
special union (ctf_dtdef_t.dtd_u) in the dynamic type definition
structure, then picking the members out of this structure at
serialization time and packing them into their final form.
This has the advantage that the ctf_add_* code doesn't need to know
anything about the final CTF representation, but the significant
disadvantage that all code that looks up types in any way needs two code
paths, one for dynamic types, one for all others. Historically libctf
"handled" this by not supporting most type lookups on dynamic types at
all until ctf_update was called to do a complete reserialization of the
entire dict (it didn't emit an error, it just emitted wrong results).
Since commit 676c3ecbad6e9c4, which eliminated ctf_update in favour of
the internal-only ctf_serialize function, all the type-lookup paths
grew an extra branch to handle dynamic types.
We can eliminate this branch again by dropping the dtd_u stuff and
simply writing out the vlen in (close to) its final form at ctf_add_*
time: type lookup for types using this approach is then identical for
types in writable dicts and types that are in read-only ones, and
serialization is also simplified (we just need to write out the vlen
we already created).
The only complexity lies in type kinds for which multiple
vlen representations are valid depending on properties of the type,
e.g. structures. But we can start simple, adjusting ints, floats,
and slices to work this way, and leaving everything else as is.
libctf/ChangeLog
2021-03-18 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (ctf_dtdef_t) <dtd_u.dtu_enc>: Remove.
<dtd_u.dtu_slice>: Likewise.
<dtd_vlen>: New.
* ctf-create.c (ctf_add_generic): Perhaps allocate it. All
callers adjusted.
(ctf_dtd_delete): Free it.
(ctf_add_slice): Use the dtd_vlen, not dtu_enc.
(ctf_add_encoded): Likewise. Assert that this must be an int or
float.
* ctf-serialize.c (ctf_emit_type_sect): Just copy the dtd_vlen.
* ctf-dedup.c (ctf_dedup_rhash_type): Use the dtd_vlen, not
dtu_slice.
* ctf-types.c (ctf_type_reference): Likewise.
(ctf_type_encoding): Remove most dynamic-type-specific code: just
get the vlen from the right place. Report failure to look up the
underlying type's encoding.
|
|
It is perfectly possible to have dynamically allocated data owned by a
specific dict: you just have to teach ctf_serialize about it.
libctf/ChangeLog
2021-03-18 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (ctf_dict_t): Fix comment.
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|
When CTF linking is done, the linker has to track the association
between types in the inputs and types in the outputs. The deduplicator
does this via the cd_output_emission_hashes, which maps from hashes of
types (valid in both the input and output) to the IDs of types in the
specific dict in which the cd_emission_hashes is held. However, the
nondeduplicating linker and ctf_add_type used a different mechanism, a
dedicated hashtab stored in the ctf_link_type_mapping, populated via
ctf_add_type_mapping and queried via the ctf_type_mapping function. To
allow the same functions to be used for variable and symbol population
in both the deduplicating and nondeduplicating linker, the deduplicator
carefully transferred all its input->output mappings into this hashtab
before returning.
This is *expensive*. The number of entries in this hashtab scales as the
number of input types, and unlike the hashing machinery the type mapping
machinery (the only other thing which scales that way) has not been much
optimized.
Now the nondeduplicating linker is gone, we can throw this out, move
the existing type mapping machinery to ctf-create.c and dedicate it to
ctf_add_type alone, and add a new function ctf_dedup_type_mapping which
uses the deduplicator's built-in knowledge of type mappings directly,
without requiring an expensive repopulation phase.
This speeds up a test link of nouveau.ko (a good worst-case candidate
with a lot of types in each of a lot of input files) from 9.11s to 7.15s
in my testing, a speedup of over 20%.
libctf/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (ctf_dict_t) <ctf_link_type_mapping>: No longer used
by the nondeduplicating linker.
(ctf_add_type_mapping): Removed, now static.
(ctf_type_mapping): Likewise.
(ctf_dedup_type_mapping): New.
(ctf_dedup_t) <cd_input_nums>: New.
* ctf-dedup.c (ctf_dedup_init): Populate it.
(ctf_dedup_fini): Free it again. Emphasise that this has to be
the last thing called.
(ctf_dedup): Populate it.
(ctf_dedup_populate_type_mapping): Removed.
(ctf_dedup_populate_type_mappings): Likewise.
(ctf_dedup_emit): No longer call it. No longer call
ctf_dedup_fini either.
(ctf_dedup_type_mapping): New.
* ctf-link.c (ctf_unnamed_cuname): New.
(ctf_create_per_cu): Arguments must be non-null now.
(ctf_in_member_cb_arg): Removed.
(ctf_link): No longer populate it. No longer discard the
mapping table.
(ctf_link_deduplicating_one_symtypetab): Use
ctf_dedup_type_mapping, not ctf_type_mapping. Use
ctf_unnamed_cuname.
(ctf_link_one_variable): Likewise. Pass in args individually: no
longer a ctf_variable_iter callback.
(empty_link_type_mapping): Removed.
(ctf_link_deduplicating_variables): Use ctf_variable_next, not
ctf_variable_iter. No longer pack arguments to
ctf_link_one_variable into a struct.
(ctf_link_deduplicating_per_cu): Call ctf_dedup_fini once
all link phases are done.
(ctf_link_deduplicating): Likewise.
(ctf_link_intern_extern_string): Improve comment.
(ctf_add_type_mapping): Migrate...
(ctf_type_mapping): ... these functions...
* ctf-create.c (ctf_add_type_mapping): ... here...
(ctf_type_mapping): ... and make static, for the sole use of
ctf_add_type.
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The existing ctf_lookup_by_symbol and ctf_arc_lookup_symbol functions
suffice to look up the types of symbols if the caller already has a
symbol number. But the caller often doesn't have one of those and only
knows the name of the symbol: also, in object files, the caller might
not have a useful symbol number in any sense (and neither does libctf:
the 'symbol number' we use in that case literally starts at 0 for the
lexicographically first-sorted symbol in the symtypetab and counts those
symbols, so it corresponds to nothing useful).
This means that even though object files have a symtypetab (generated by
the compiler or by ld -r), the only way we can look up anything in it is
to iterate over all symbols in turn with ctf_symbol_next until we find
the one we want.
This is unhelpful and pointlessly inefficient.
So add a pair of functions to look up symbols by name in a dict and in a
whole archive: ctf_lookup_by_symbol_name and ctf_arc_lookup_symbol_name.
These are identical to the existing functions except that they take
symbol names rather than symbol numbers.
To avoid insane repetition, we do some refactoring in the process, so
that both ctf_lookup_by_symbol and ctf_arc_lookup_symbol turn into thin
wrappers around internal functions that do both lookup by symbol index
and lookup by name. This massively reduces code duplication because
even the existing lookup-by-index stuff wants to use a name sometimes
(when looking up in indexed sections), and the new lookup-by-name stuff
has to turn it into an index sometimes (when looking up in non-indexed
sections): doing it this way lets us share most of that.
The actual name->index lookup is done by ctf_lookup_symbol_idx. We do
not anticipate this lookup to be as heavily used as ld.so symbol lookup
by many orders of magnitude, so using the ELF symbol hashes would
probably take more time to read them than is saved by using the hashes,
and it adds a lot of complexity. Instead, do a linear search for the
symbol name, caching all the name -> index mappings as we go, so that
future searches are likely to hit in the cache. To avoid having to
repeat this search over and over in a CTF archive when
ctf_arc_lookup_symbol_name is used, have cached archive lookups (the
sort done by ctf_arc_lookup_symbol* and the ctf_archive_next iterator)
pick out the first dict they cache in a given archive and store it in a
new ctf_archive field, ctfi_crossdict_cache. This can be used to store
cross-dictionary cached state that depends on things like the ELF symbol
table rather than the contents of any one dict. ctf_lookup_symbol_idx
then caches its name->index mappings in the dictionary named in the
crossdict cache, if any, so that ctf_lookup_symbol_idx in other dicts
in the same archive benefit from the previous linear search, and the
symtab only needs to be scanned at most once.
(Note that if you call ctf_lookup_by_symbol_name in one specific dict,
and then follow it with a ctf_arc_lookup_symbol_name, the former will
not use the crossdict cache because it's only populated by the dict
opens in ctf_arc_lookup_symbol_name. This is harmless except for a small
one-off waste of memory and time: it's only a cache, after all. We can
fix this later by using the archive caching machinery more
aggressively.)
In ctf-archive, we do similar things, turning ctf_arc_lookup_symbol into
a wrapper around a new function that does both index -> ID and name ->
ID lookups across all dicts in an archive. We add a new
ctfi_symnamedicts cache that maps symbol names to the ctf_dict_t * that
it was found in (so that linear searches for symbols don't need to be
repeated): but we also *remove* a cache, the ctfi_syms cache that was
memoizing the actual ctf_id_t returned from every call to
ctf_arc_lookup_symbol. This is pointless: all it saves is one call to
ctf_lookup_by_symbol, and that's basically an array lookup and nothing
more so isn't worth caching. (Equally, given that symbol -> index
mappings are cached by ctf_lookup_by_symbol_name, those calls are nearly
free after the first call, so there's no point caching the ctf_id_t in
that case either.)
We fix up one test that was doing manual symbol lookup to use
ctf_arc_lookup_symbol instead, and enhance it to check that the caching
layer is not totally broken: we also add a new test to do lookups in a
.o file, and another to do lookups in an archive with conflicted types
and make sure that sort of multi-dict lookup is actually working.
include/ChangeLog
2021-02-17 Nick Alcock <nick.alcock@oracle.com>
* ctf-api.h (ctf_arc_lookup_symbol_name): New.
(ctf_lookup_by_symbol_name): Likewise.
libctf/ChangeLog
2021-02-17 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (ctf_dict_t) <ctf_symhash>: New.
<ctf_symhash_latest>: Likewise.
(struct ctf_archive_internal) <ctfi_crossdict_cache>: New.
<ctfi_symnamedicts>: New.
<ctfi_syms>: Remove.
(ctf_lookup_symbol_name): Remove.
* ctf-lookup.c (ctf_lookup_symbol_name): Propagate errors from
parent properly. Make static.
(ctf_lookup_symbol_idx): New, linear search for the symbol name,
cached in the crossdict cache's ctf_symhash (if available), or
this dict's (otherwise).
(ctf_try_lookup_indexed): Allow the symname to be passed in.
(ctf_lookup_by_symbol): Turn into a wrapper around...
(ctf_lookup_by_sym_or_name): ... this, supporting name lookup too,
using ctf_lookup_symbol_idx in non-writable dicts. Special-case
name lookup in dynamic dicts without reported symbols, which have
no symtab or dynsymidx but where name lookup should still work.
(ctf_lookup_by_symbol_name): New, another wrapper.
* ctf-archive.c (enosym): Note that this is present in
ctfi_symnamedicts too.
(ctf_arc_close): Adjust for removal of ctfi_syms. Free the
ctfi_symnamedicts.
(ctf_arc_flush_caches): Likewise.
(ctf_dict_open_cached): Memoize the first cached dict in the
crossdict cache.
(ctf_arc_lookup_symbol): Turn into a wrapper around...
(ctf_arc_lookup_sym_or_name): ... this. No longer cache
ctf_id_t lookups: just call ctf_lookup_by_symbol as needed (but
still cache the dicts those lookups succeed in). Add
lookup-by-name support, with dicts of successful lookups cached in
ctfi_symnamedicts. Refactor the caching code a bit.
(ctf_arc_lookup_symbol_name): New, another wrapper.
* ctf-open.c (ctf_dict_close): Free the ctf_symhash.
* libctf.ver (LIBCTF_1.2): New version. Add
ctf_lookup_by_symbol_name, ctf_arc_lookup_symbol_name.
* testsuite/libctf-lookup/enum-symbol.c (main): Use
ctf_arc_lookup_symbol rather than looking up the name ourselves.
Fish it out repeatedly, to make sure that symbol caching isn't
broken.
(symidx_64): Remove.
(symidx_32): Remove.
* testsuite/libctf-lookup/enum-symbol-obj.lk: Test symbol lookup
in an unlinked object file (indexed symtypetab sections only).
* testsuite/libctf-writable/symtypetab-nonlinker-writeout.c
(try_maybe_reporting): Check symbol types via
ctf_lookup_by_symbol_name as well as ctf_symbol_next.
* testsuite/libctf-lookup/conflicting-type-syms.*: New test of
lookups in a multi-dict archive.
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The variable section in a CTF dict is meant to contain the types of
variables that do not appear in the symbol table (mostly file-scope
static declarations). We implement this by having the compiler emit
all potential data symbols into both sections, then delete those
symbols from the variable section that correspond to data symbols the
linker has reported.
Unfortunately, the check for this in ctf_serialize is wrong: rather than
checking the set of linker-reported symbols, we check the set of names
in the data object symtypetab section: if the linker has reported no
symbols at all (usually if ld -r has been run, or if a non-linker
program that does not use symbol tables is calling ctf_link) this will
include every single symbol, emptying the variable section completely.
Worse, when ld -r is in use, we want to force writeout of every
symtypetab entry on the inputs, in an indexed section, whether or not
the linker has reported them, since this isn't a final link yet and the
symbol table is not finalized (and may grow more symbols than the linker
has yet reported). But the check for this is flawed too: we were
relying on ctf_link_shuffle_syms not having been called if no symbols
exist, but that function is *always* called by ld even when ld -r is in
use: ctf_link_add_linker_symbol is the one that's not called when there
are no symbols.
We clearly need to rethink this. Using the emptiness of the set of
reported symbols as a test for ld -r is just ugly: the linker already
knows if ld -r is underway and can just tell us. So add a new linker
flag CTF_LINK_NO_FILTER_REPORTED_SYMS that is set to stop the linker
filtering the symbols in the symtypetab sections using the set that the
linker has reported: use the presence or absence of this flag to
determine whether to emit unindexed symtabs: we only remove entries from
the variable section when filtering symbols, and we only remove them if
they are in the reported symbol set, fixing the case where no symbols
are reported by the linker at all.
(The negative sense of the new CTF_LINK flag is intentional: the common
case, both for ld and for simple tools that want to do a ctf_link with
no ELF symbol table in sight, is probably to filter out symbols that no
linker has reported: i.e., for the simple tools, all of them.)
There's another wrinkle, though. It is quite possible for a non-linker
to add symbols to a dict via ctf_add_*_sym and then write it out via the
ctf_write APIs: perhaps it's preparing a dict for a later linker
invocation. Right now this would not lead to anything terribly
meaningful happening: ctf_serialize just assumes it was called via
ctf_link if symbols are present. So add an (internal-to-libctf) flag
that indicates that a writeout is happening via ctf_link_write, and set
it there (propagating it to child dicts as needed). ctf_serialize can
then spot when it is not being called by a linker, and arrange to always
write out an indexed, sorted symtypetab for fastest possible future
symbol lookup by name in that case. (The writeouts done by ld -r are
unsorted, because the only thing likely to use those symtabs is the
linker, which doesn't benefit from symtypetab sorting.)
Tests added for all three linking cases (ld -r, ld -shared, ld), with a
bit of testsuite framework enhancement to stop it unconditionally
linking the CTF to be checked by the lookup program with -shared, so
tests can now examine CTF linked with -r or indeed with no flags at all,
though the output filename is still foo.so even in this case.
Another test added for the non-linker case that endeavours to determine
whether the symtypetab is sorted by examining the order of entries
returned from ctf_symbol_next: nobody outside libctf should rely on
this ordering, but this test is not outside libctf :)
include/ChangeLog
2021-01-26 Nick Alcock <nick.alcock@oracle.com>
* ctf-api.h (CTF_LINK_NO_FILTER_REPORTED_SYMS): New.
ld/ChangeLog
2021-01-26 Nick Alcock <nick.alcock@oracle.com>
* ldlang.c (lang_merge_ctf): Set CTF_LINK_NO_FILTER_REPORTED_SYMS
when appropriate.
libctf/ChangeLog
2021-01-27 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.c (_libctf_nonnull_): Add parameters.
(LCTF_LINKING): New flag.
(ctf_dict_t) <ctf_link_flags>: Mention it.
* ctf-link.c (ctf_link): Keep LCTF_LINKING set across call.
(ctf_write): Likewise, including in child dictionaries.
(ctf_link_shuffle_syms): Make sure ctf_dynsyms is NULL if there
are no reported symbols.
* ctf-create.c (symtypetab_delete_nonstatic_vars): Make sure
the variable has been reported as a symbol by the linker.
(symtypetab_skippable): Mention relationship between SYMFP and the
flags.
(symtypetab_density): Adjust nonnullity. Exit early if no symbols
were reported and force-indexing is off (i.e., we are doing a
final link).
(ctf_serialize): Handle the !LCTF_LINKING case by writing out an
indexed, sorted symtypetab (and allow SYMFP to be NULL in this
case). Turn sorting off if this is a non-final link. Only delete
nonstatic vars if we are filtering symbols and the linker has
reported some.
* testsuite/libctf-regression/nonstatic-var-section-ld-r*:
New test of variable and symtypetab section population when
ld -r is used.
* testsuite/libctf-regression/nonstatic-var-section-ld-executable.lk:
Likewise, when ld of an executable is used.
* testsuite/libctf-regression/nonstatic-var-section-ld.lk:
Likewise, when ld -shared alone is used.
* testsuite/libctf-regression/nonstatic-var-section-ld*.c:
Lookup programs for the above.
* testsuite/libctf-writable/symtypetab-nonlinker-writeout.*: New
test, testing survival of symbols across ctf_write paths.
* testsuite/lib/ctf-lib.exp (run_lookup_test): New option,
nonshared, suppressing linking of the SOURCE with -shared.
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When you look up a type by name using ctf_lookup_by_name, in most cases
libctf can just strip off any qualifiers and look for the name, but for
pointer types this doesn't work, since the caller will want the pointer
type itself. But pointer types are nameless, and while they cite the
types they point to, looking up a type by name requires a link going the
*other way*, from the type pointed to to the pointer type that points to
it.
libctf has always built this up at open time: ctf_ptrtab is an array of
type indexes pointing from the index of every type to the index of the
type that points to it. But because it is built up at open time (and
because it uses type indexes and not type IDs) it is restricted to
working within a single dict and ignoring parent/child
relationships. This is normally invisible, unless you manage to get a
dict with a type in the parent but the only pointer to it in a child.
The ctf_ptrtab will not track this relationship, so lookups of this
pointer type by name will fail. Since which type is in the parent and
which in the child is largely opaque to the user (which goes where is up
to the deduplicator, and it can and does reshuffle things to save
space), this leads to a very bad user experience, with an
obviously-visible pointer type which ctf_lookup_by_name claims doesn't
exist.
The fix is to have another array, ctf_pptrtab, which is populated in
child dicts: like the parent's ctf_ptrtab, it has one element per type
in the parent, but is all zeroes except for those types which are
pointed to by types in the child: so it maps parent dict indices to
child dict indices. The array is grown, and new child types scanned,
whenever a lookup happens and new types have been added to the child
since the last time a lookup happened that might need the pptrtab.
(So for non-writable dicts, this only happens once, since new types
cannot be added to non-writable dicts at all.)
Since this introduces new complexity (involving updating only part of
the ctf_pptrtab) which is only seen when a writable dict is in use, we
introduce a new libctf-writable testsuite that contains lookup tests
with no corresponding CTF-containing .c files (which can thus be run
even on platforms with no .ctf-section support in the linker yet), and
add a test to check that creation of pointers in children to types in
parents and a following lookup by name works as expected. The non-
writable case is tested in a new libctf-regression testsuite which is
used to track now-fixed outright bugs in libctf.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (ctf_dict_t) <ctf_pptrtab>: New.
<ctf_pptrtab_len>: New.
<ctf_pptrtab_typemax>: New.
* ctf-create.c (ctf_serialize): Update accordingly.
(ctf_add_reftype): Note that we don't need to update pptrtab here,
despite updating ptrtab.
* ctf-open.c (ctf_dict_close): Destroy the pptrtab.
(ctf_import): Likewise.
(ctf_import_unref): Likewise.
* ctf-lookup.c (grow_pptrtab): New.
(refresh_pptrtab): New, update a pptrtab.
(ctf_lookup_by_name): Turn into a wrapper around (and rename to)...
(ctf_lookup_by_name_internal): ... this: construct the pptrtab, and
use it in addition to the parent's ptrtab when parent dicts are
searched.
* testsuite/libctf-regression/regression.exp: New testsuite for
regression tests.
* testsuite/libctf-regression/pptrtab*: New test.
* testsuite/libctf-writable/writable.exp: New testsuite for tests of
writable CTF dicts.
* testsuite/libctf-writable/pptrtab*: New test.
|
|
libctf has no intrinsic support for the GCC unnamed structure member
extension. This principally means that you can't look up named members
inside unnamed struct or union members via ctf_member_info: you have to
tiresomely find out the type ID of the unnamed members via iteration,
then look in each of these.
This is ridiculous. Fix it by extending ctf_member_info so that it
recurses into unnamed members for you: this is still unambiguous because
GCC won't let you create ambiguously-named members even in the presence
of this extension.
For consistency, and because the release hasn't happened and we can
still do this, break the ctf_member_next API and add flags: we specify
one flag, CTF_MN_RECURSE, which if set causes ctf_member_next to
automatically recurse into unnamed members for you, returning not only
the members themselves but all their contained members, so that you can
use ctf_member_next to identify every member that it would be valid to
call ctf_member_info with.
New lookup tests are added for all of this.
include/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* ctf-api.h (CTF_MN_RECURSE): New.
(ctf_member_next): Add flags argument.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (struct ctf_next) <u.ctn_next>: Move to...
<ctn_next>: ... here.
* ctf-util.c (ctf_next_destroy): Unconditionally destroy it.
* ctf-lookup.c (ctf_symbol_next): Adjust accordingly.
* ctf-types.c (ctf_member_iter): Reimplement in terms of...
(ctf_member_next): ... this. Support recursive unnamed member
iteration (off by default).
(ctf_member_info): Look up members in unnamed sub-structs.
* ctf-dedup.c (ctf_dedup_rhash_type): Adjust ctf_member_next call.
(ctf_dedup_emit_struct_members): Likewise.
* testsuite/libctf-lookup/struct-iteration-ctf.c: Test empty unnamed
members, and a normal member after the end.
* testsuite/libctf-lookup/struct-iteration.c: Verify that
ctf_member_count is consistent with the number of successful returns
from a non-recursive ctf_member_next.
* testsuite/libctf-lookup/struct-iteration-*: New, test iteration
over struct members.
* testsuite/libctf-lookup/struct-lookup.c: New test.
* testsuite/libctf-lookup/struct-lookup.lk: New test.
|
|
|
|
The CTF symbol lookup machinery added recently has one deficit: it
assumes the symtab is in the machine's native endianness. This is
always true when the linker is writing out symtabs (because cross
linkers byteswap symbols only after libctf has been called on them), but
may be untrue in the cross case when the linker or another tool
(objdump, etc) is reading them.
Unfortunately the easy way to model this to the caller, as an endianness
field in the ctf_sect_t, is precluded because doing so would change the
size of the ctf_sect_t, which would be an ABI break. So, instead, allow
the endianness of the symtab to be set after open time, by calling one
of the two new API functions ctf_symsect_endianness (for ctf_dict_t's)
or ctf_arc_symsect_endianness (for entire ctf_archive_t's). libctf
calls these functions automatically for objects opened via any of the
BFD-aware mechanisms (ctf_bfdopen, ctf_bfdopen_ctfsect, ctf_fdopen,
ctf_open, or ctf_arc_open), but the various mechanisms that just take
raw ctf_sect_t's will assume the symtab is in native endianness and need
a later call to ctf_*symsect_endianness to adjust it if needed. (This
call is basically free if the endianness is actually native: it only
costs anything if the symtab endianness was previously guessed wrong,
and there is a symtab, and we are using it directly rather than using
symtab indexing.)
Obviously, calling ctf_lookup_by_symbol or ctf_symbol_next before the
symtab endianness is correctly set will probably give wrong answers --
but you can set it at any time as long as it is before then.
include/ChangeLog
2020-11-23 Nick Alcock <nick.alcock@oracle.com>
* ctf-api.h: Style nit: remove () on function names in comments.
(ctf_sect_t): Mention endianness concerns.
(ctf_symsect_endianness): New declaration.
(ctf_arc_symsect_endianness): Likewise.
libctf/ChangeLog
2020-11-23 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (ctf_dict_t) <ctf_symtab_little_endian>: New.
(struct ctf_archive_internal) <ctfi_symsect_little_endian>: Likewise.
* ctf-create.c (ctf_serialize): Adjust for new field.
* ctf-open.c (init_symtab): Note the semantics of repeated calls.
(ctf_symsect_endianness): New.
(ctf_bufopen_internal): Set ctf_symtab_little_endian suitably for
the native endianness.
(_Static_assert): Moved...
(swap_thing): ... with this...
* swap.h: ... to here.
* ctf-util.c (ctf_elf32_to_link_sym): Use it, byteswapping the
Elf32_Sym if the ctf_symtab_little_endian demands it.
(ctf_elf64_to_link_sym): Likewise swap the Elf64_Sym if needed.
* ctf-archive.c (ctf_arc_symsect_endianness): New, set the
endianness of the symtab used by the dicts in an archive.
(ctf_archive_iter_internal): Initialize to unknown (assumed native,
do not call ctf_symsect_endianness).
(ctf_dict_open_by_offset): Call ctf_symsect_endianness if need be.
(ctf_dict_open_internal): Propagate the endianness down.
(ctf_dict_open_sections): Likewise.
* ctf-open-bfd.c (ctf_bfdopen_ctfsect): Get the endianness from the
struct bfd and pass it down to the archive.
* libctf.ver: Add ctf_symsect_endianness and
ctf_arc_symsect_endianness.
|
|
CTF archives may contain multiple dicts, each of which contain many
types and possibly a bunch of symtypetab entries relating to those
types: each symtypetab entry is going to appear in exactly one dict,
with the corresponding entries in the other dicts empty (either pads, or
indexed symtypetabs that do not mention that symbol). But users of
libctf usually want to get back the type associated with a symbol
without having to dig around to find out which dict that type might be
in.
This adds machinery to do that -- and since you probably want to do it
repeatedly, it adds internal caching to the ctf-archive machinery so
that iteration over archives via ctf_archive_next and repeated symbol
lookups do not have to repeatedly reopen the archive. (Iteration using
ctf_archive_iter will gain caching soon.)
Two new API functions:
ctf_dict_t *
ctf_arc_lookup_symbol (ctf_archive_t *arc, unsigned long symidx,
ctf_id_t *typep, int *errp);
This looks up the symbol with index SYMIDX in the archive ARC, returning
the dictionary in which it resides and optionally the type index as
well. Errors are returned in ERRP. The dict should be
ctf_dict_close()d when done, but is also cached inside the ctf_archive
so that the open cost is only paid once. The result of the symbol
lookup is also cached internally, so repeated lookups of the same symbol
are nearly free.
void ctf_arc_flush_caches (ctf_archive_t *arc);
Flush all the caches. Done at close time, but also available as an API
function if users want to do it by hand.
include/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* ctf-api.h (ctf_arc_lookup_symbol): New.
(ctf_arc_flush_caches): Likewise.
* ctf.h: Document new auto-ctf_import behaviour.
libctf/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (struct ctf_archive_internal) <ctfi_dicts>: New, dicts
the archive machinery has opened and cached.
<ctfi_symdicts>: New, cache of dicts containing symbols looked up.
<ctfi_syms>: New, cache of types of symbols looked up.
* ctf-archive.c (ctf_arc_close): Free them on close.
(enosym): New, flag entry for 'symbol not present'.
(ctf_arc_import_parent): New, automatically import the parent from
".ctf" if this is a child in an archive and ".ctf" is present.
(ctf_dict_open_sections): Use it.
(ctf_archive_iter_internal): Likewise.
(ctf_cached_dict_close): New, thunk around ctf_dict_close.
(ctf_dict_open_cached): New, open and cache a dict.
(ctf_arc_flush_caches): New, flush the caches.
(ctf_arc_lookup_symbol): New, look up a symbol in (all members of)
an archive, and cache the lookup.
(ctf_archive_iter): Note the new caching behaviour.
(ctf_archive_next): Use ctf_dict_open_cached.
* libctf.ver: Add ctf_arc_lookup_symbol and ctf_arc_flush_caches.
|
|
This adds facilities to write out the function info and data object
sections, which efficiently map from entries in the symbol table to
types. The write-side code is entirely new: the read-side code was
merely significantly changed and support for indexed tables added
(pointed to by the no-longer-unused cth_objtidxoff and cth_funcidxoff
header fields).
With this in place, you can use ctf_lookup_by_symbol to look up the
types of symbols of function and object type (and, as before, you can
use ctf_lookup_variable to look up types of file-scope variables not
present in the symbol table, as long as you know their name: but
variables that are also data objects are now found in the data object
section instead.)
(Compatible) file format change:
The CTF spec has always said that the function info section looks much
like the CTF_K_FUNCTIONs in the type section: an info word (including an
argument count) followed by a return type and N argument types. This
format is suboptimal: it means function symbols cannot be deduplicated
and it causes a lot of ugly code duplication in libctf. But
conveniently the compiler has never emitted this! Because it has always
emitted a rather different format that libctf has never accepted, we can
be sure that there are no instances of this function info section in the
wild, and can freely change its format without compatibility concerns or
a file format version bump. (And since it has never been emitted in any
code that generated any older file format version, either, we need keep
no code to read the format as specified at all!)
So the function info section is now specified as an array of uint32_t,
exactly like the object data section: each entry is a type ID in the
type section which must be of kind CTF_K_FUNCTION, the prototype of
this function.
This allows function types to be deduplicated and also correctly encodes
the fact that all functions declared in C really are types available to
the program: so they should be stored in the type section like all other
types. (In format v4, we will be able to represent the types of static
functions as well, but that really does require a file format change.)
We introduce a new header flag, CTF_F_NEWFUNCINFO, which is set if the
new function info format is in use. A sufficiently new compiler will
always set this flag. New libctf will always set this flag: old libctf
will refuse to open any CTF dicts that have this flag set. If the flag
is not set on a dict being read in, new libctf will disregard the
function info section. Format v4 will remove this flag (or, rather, the
flag has no meaning there and the bit position may be recycled for some
other purpose).
New API:
Symbol addition:
ctf_add_func_sym: Add a symbol with a given name and type. The
type must be of kind CTF_K_FUNCTION (a function
pointer). Internally this adds a name -> type
mapping to the ctf_funchash in the ctf_dict.
ctf_add_objt_sym: Add a symbol with a given name and type. The type
kind can be anything, including function pointers.
This adds to ctf_objthash.
These both treat symbols as name -> type mappings: the linker associates
symbol names with symbol indexes via the ctf_link_shuffle_syms callback,
which sets up the ctf_dynsyms/ctf_dynsymidx/ctf_dynsymmax fields in the
ctf_dict. Repeated relinks can add more symbols.
Variables that are also exposed as symbols are removed from the variable
section at serialization time.
CTF symbol type sections which have enough pads, defined by
CTF_INDEX_PAD_THRESHOLD (whether because they are in dicts with symbols
where most types are unknown, or in archive where most types are defined
in some child or parent dict, not in this specific dict) are sorted by
name rather than symidx and accompanied by an index which associates
each symbol type entry with a name: the existing ctf_lookup_by_symbol
will map symbol indexes to symbol names and look the names up in the
index automatically. (This is currently ELF-symbol-table-dependent, but
there is almost nothing specific to ELF in here and we can add support
for other symbol table formats easily).
The compiler also uses index sections to communicate the contents of
object file symbol tables without relying on any specific ordering of
symbols: it doesn't need to sort them, and libctf will detect an
unsorted index section via the absence of the new CTF_F_IDXSORTED header
flag, and sort it if needed.
Iteration:
ctf_symbol_next: Iterator which returns the types and names of symbols
one by one, either for function or data symbols.
This does not require any sorting: the ctf_link machinery uses it to
pull in all the compiler-provided symbols cheaply, but it is not
restricted to that use.
(Compatible) changes in API:
ctf_lookup_by_symbol: can now be called for object and function
symbols: never returns ECTF_NOTDATA (which is
now not thrown by anything, but is kept for
compatibility and because it is a plausible
error that we might start throwing again at some
later date).
Internally we also have changes to the ctf-string functionality so that
"external" strings (those where we track a string -> offset mapping, but
only write out an offset) can be consulted via the usual means
(ctf_strptr) before the strtab is written out. This is important
because ctf_link_add_linker_symbol can now be handed symbols named via
strtab offsets, and ctf_link_shuffle_syms must figure out their actual
names by looking in the external symtab we have just been fed by the
ctf_link_add_strtab callback, long before that strtab is written out.
include/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* ctf-api.h (ctf_symbol_next): New.
(ctf_add_objt_sym): Likewise.
(ctf_add_func_sym): Likewise.
* ctf.h: Document new function info section format.
(CTF_F_NEWFUNCINFO): New.
(CTF_F_IDXSORTED): New.
(CTF_F_MAX): Adjust accordingly.
libctf/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h (CTF_INDEX_PAD_THRESHOLD): New.
(_libctf_nonnull_): Likewise.
(ctf_in_flight_dynsym_t): New.
(ctf_dict_t) <ctf_funcidx_names>: Likewise.
<ctf_objtidx_names>: Likewise.
<ctf_nfuncidx>: Likewise.
<ctf_nobjtidx>: Likewise.
<ctf_funcidx_sxlate>: Likewise.
<ctf_objtidx_sxlate>: Likewise.
<ctf_objthash>: Likewise.
<ctf_funchash>: Likewise.
<ctf_dynsyms>: Likewise.
<ctf_dynsymidx>: Likewise.
<ctf_dynsymmax>: Likewise.
<ctf_in_flight_dynsym>: Likewise.
(struct ctf_next) <u.ctn_next>: Likewise.
(ctf_symtab_skippable): New prototype.
(ctf_add_funcobjt_sym): Likewise.
(ctf_dynhash_sort_by_name): Likewise.
(ctf_sym_to_elf64): Rename to...
(ctf_elf32_to_link_sym): ... this, and...
(ctf_elf64_to_link_sym): ... this.
* ctf-open.c (init_symtab): Check for lack of CTF_F_NEWFUNCINFO
flag, and presence of index sections. Refactor out
ctf_symtab_skippable and ctf_elf*_to_link_sym, and use them. Use
ctf_link_sym_t, not Elf64_Sym. Skip initializing objt or func
sxlate sections if corresponding index section is present. Adjust
for new func info section format.
(ctf_bufopen_internal): Add ctf_err_warn to corrupt-file error
handling. Report incorrect-length index sections. Always do an
init_symtab, even if there is no symtab section (there may be index
sections still).
(flip_objts): Adjust comment: func and objt sections are actually
identical in structure now, no need to caveat.
(ctf_dict_close): Free newly-added data structures.
* ctf-create.c (ctf_create): Initialize them.
(ctf_symtab_skippable): New, refactored out of
init_symtab, with st_nameidx_set check added.
(ctf_add_funcobjt_sym): New, add a function or object symbol to the
ctf_objthash or ctf_funchash, by name.
(ctf_add_objt_sym): Call it.
(ctf_add_func_sym): Likewise.
(symtypetab_delete_nonstatic_vars): New, delete vars also present as
data objects.
(CTF_SYMTYPETAB_EMIT_FUNCTION): New flag to symtypetab emitters:
this is a function emission, not a data object emission.
(CTF_SYMTYPETAB_EMIT_PAD): New flag to symtypetab emitters: emit
pads for symbols with no type (only set for unindexed sections).
(CTF_SYMTYPETAB_FORCE_INDEXED): New flag to symtypetab emitters:
always emit indexed.
(symtypetab_density): New, figure out section sizes.
(emit_symtypetab): New, emit a symtypetab.
(emit_symtypetab_index): New, emit a symtypetab index.
(ctf_serialize): Call them, emitting suitably sorted symtypetab
sections and indexes. Set suitable header flags. Copy over new
fields.
* ctf-hash.c (ctf_dynhash_sort_by_name): New, used to impose an
order on symtypetab index sections.
* ctf-link.c (ctf_add_type_mapping): Delete erroneous comment
relating to code that was never committed.
(ctf_link_one_variable): Improve variable name.
(check_sym): New, symtypetab analogue of check_variable.
(ctf_link_deduplicating_one_symtypetab): New.
(ctf_link_deduplicating_syms): Likewise.
(ctf_link_deduplicating): Call them.
(ctf_link_deduplicating_per_cu): Note that we don't call them in
this case (yet).
(ctf_link_add_strtab): Set the error on the fp correctly.
(ctf_link_add_linker_symbol): New (no longer a do-nothing stub), add
a linker symbol to the in-flight list.
(ctf_link_shuffle_syms): New (no longer a do-nothing stub), turn the
in-flight list into a mapping we can use, now its names are
resolvable in the external strtab.
* ctf-string.c (ctf_str_rollback_atom): Don't roll back atoms with
external strtab offsets.
(ctf_str_rollback): Adjust comment.
(ctf_str_write_strtab): Migrate ctf_syn_ext_strtab population from
writeout time...
(ctf_str_add_external): ... to string addition time.
* ctf-lookup.c (ctf_lookup_var_key_t): Rename to...
(ctf_lookup_idx_key_t): ... this, now we use it for syms too.
<clik_names>: New member, a name table.
(ctf_lookup_var): Adjust accordingly.
(ctf_lookup_variable): Likewise.
(ctf_lookup_by_id): Shuffle further up in the file.
(ctf_symidx_sort_arg_cb): New, callback for...
(sort_symidx_by_name): ... this new function to sort a symidx
found to be unsorted (likely originating from the compiler).
(ctf_symidx_sort): New, sort a symidx.
(ctf_lookup_symbol_name): Support dynamic symbols with indexes
provided by the linker. Use ctf_link_sym_t, not Elf64_Sym.
Check the parent if a child lookup fails.
(ctf_lookup_by_symbol): Likewise. Work for function symbols too.
(ctf_symbol_next): New, iterate over symbols with types (without
sorting).
(ctf_lookup_idx_name): New, bsearch for symbol names in indexes.
(ctf_try_lookup_indexed): New, attempt an indexed lookup.
(ctf_func_info): Reimplement in terms of ctf_lookup_by_symbol.
(ctf_func_args): Likewise.
(ctf_get_dict): Move...
* ctf-types.c (ctf_get_dict): ... here.
* ctf-util.c (ctf_sym_to_elf64): Re-express as...
(ctf_elf64_to_link_sym): ... this. Add new st_symidx field, and
st_nameidx_set (always 0, so st_nameidx can be ignored). Look in
the ELF strtab for names.
(ctf_elf32_to_link_sym): Likewise, for Elf32_Sym.
(ctf_next_destroy): Destroy ctf_next_t.u.ctn_next if need be.
* libctf.ver: Add ctf_symbol_next, ctf_add_objt_sym and
ctf_add_func_sym.
|
|
This is embarrassing.
The whole point of CTF is that it remains intact even after a binary is
stripped, providing a compact mapping from symbols to types for
everything in the externally-visible interface of an ELF object: it has
connections to the symbol table for that purpose, and to the string
table to avoid duplicating symbol names. So it's a shame that the hooks
I implemented last year served to hook it up to the .symtab and .strtab,
which obviously disappear on strip, leaving any accompanying the CTF
dict containing references to strings (and, soon, symbols) which don't
exist any more because their containing strtab has been vaporized. The
original Solaris design used .dynsym and .dynstr (well, actually,
.ldynsym, which has more symbols) which do not disappear. So should we.
Thankfully the work we did before serves as guide rails, and adjusting
things to use the .dynstr and .dynsym was fast and easy. The only
annoyance is that the dynsym is assembled inside elflink.c in a fairly
piecemeal fashion, so that the easiest way to get the symbols out was to
hook in before every call to swap_symbol_out (we also leave in a hook in
front of symbol additions to the .symtab because it seems plausible that
we might want to hook them in future too: for now that hook is unused).
We adjust things so that rather than being offered a whole hash table of
symbols at once, libctf is now given symbols one at a time, with st_name
indexes already resolved and pointing at their final .dynstr offsets:
it's now up to libctf to resolve these to names as needed using the
strtab info we pass it separately.
Some bits might be contentious. The ctf_new_dynstr callback takes an
elf_internal_sym, and this remains an elf_internal_sym right down
through the generic emulation layers into ldelfgen. This is no worse
than the elf_sym_strtab we used to pass down, but in the future when we
gain non-ELF CTF symtab support we might want to lower the
elf_internal_sym to some other representation (perhaps a
ctf_link_symbol) in bfd or in ldlang_ctf_new_dynsym. We rename the
'apply_strsym' hooks to 'acquire_strings' instead, becuse they no longer
have anything to do with symbols.
There are some API changes to pieces of API which are technically public
but actually totally unused by anything and/or unused by anything but ld
so they can change freely: the ctf_link_symbol gains new fields to allow
symbol names to be given as strtab offsets as well as strings, and a
symidx so that the symbol index can be passed in. ctf_link_shuffle_syms
loses its callback parameter: the idea now is that linkers call the new
ctf_link_add_linker_symbol for every symbol in .dynsym, feed in all the
strtab entries with ctf_link_add_strtab, and then a call to
ctf_link_shuffle_syms will apply both and arrange to use them to reorder
the CTF symtab at CTF serialization time (which is coming in the next
commit).
Inside libctf we have a new preamble flag CTF_F_DYNSTR which is always
set in v3-format CTF dicts from this commit forwards: CTF dicts without
this flag are associated with .strtab like they used to be, so that old
dicts' external strings don't turn to garbage when loaded by new libctf.
Dicts with this flag are associated with .dynstr and .dynsym instead.
(The flag is not the next in sequence because this commit was written
quite late: the missing flags will be filled in by the next commit.)
Tests forthcoming in a later commit in this series.
bfd/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* elflink.c (elf_finalize_dynstr): Call examine_strtab after
dynstr finalization.
(elf_link_swap_symbols_out): Don't call it here. Call
ctf_new_symbol before swap_symbol_out.
(elf_link_output_extsym): Call ctf_new_dynsym before
swap_symbol_out.
(bfd_elf_final_link): Likewise.
* elf.c (swap_out_syms): Pass in bfd_link_info. Call
ctf_new_symbol before swap_symbol_out.
(_bfd_elf_compute_section_file_positions): Adjust.
binutils/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* readelf.c (dump_section_as_ctf): Use .dynsym and .dynstr, not
.symtab and .strtab.
include/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* bfdlink.h (struct elf_sym_strtab): Replace with...
(struct elf_internal_sym): ... this.
(struct bfd_link_callbacks) <examine_strtab>: Take only a
symstrtab argument.
<ctf_new_symbol>: New.
<ctf_new_dynsym>: Likewise.
* ctf-api.h (struct ctf_link_sym) <st_symidx>: New.
<st_nameidx>: Likewise.
<st_nameidx_set>: Likewise.
(ctf_link_iter_symbol_f): Removed.
(ctf_link_shuffle_syms): Remove most parameters, just takes a
ctf_dict_t now.
(ctf_link_add_linker_symbol): New, split from
ctf_link_shuffle_syms.
* ctf.h (CTF_F_DYNSTR): New.
(CTF_F_MAX): Adjust.
ld/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* ldelfgen.c (struct ctf_strsym_iter_cb_arg): Rename to...
(struct ctf_strtab_iter_cb_arg): ... this, changing fields:
<syms>: Remove.
<symcount>: Remove.
<symstrtab>: Rename to...
<strtab>: ... this.
(ldelf_ctf_strtab_iter_cb): Adjust.
(ldelf_ctf_symbols_iter_cb): Remove.
(ldelf_new_dynsym_for_ctf): New, tell libctf about a single
symbol.
(ldelf_examine_strtab_for_ctf): Rename to...
(ldelf_acquire_strings_for_ctf): ... this, only doing the strtab
portion and not symbols.
* ldelfgen.h: Adjust declarations accordingly.
* ldemul.c (ldemul_examine_strtab_for_ctf): Rename to...
(ldemul_acquire_strings_for_ctf): ... this.
(ldemul_new_dynsym_for_ctf): New.
* ldemul.h: Adjust declarations accordingly.
* ldlang.c (ldlang_ctf_apply_strsym): Rename to...
(ldlang_ctf_acquire_strings): ... this.
(ldlang_ctf_new_dynsym): New.
(lang_write_ctf): Call ldemul_new_dynsym_for_ctf with NULL to do
the actual symbol shuffle.
* ldlang.h (struct elf_strtab_hash): Adjust accordingly.
* ldmain.c (bfd_link_callbacks): Wire up new/renamed callbacks.
libctf/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* ctf-link.c (ctf_link_shuffle_syms): Adjust.
(ctf_link_add_linker_symbol): New, unimplemented stub.
* libctf.ver: Add it.
* ctf-create.c (ctf_serialize): Set CTF_F_DYNSTR on newly-serialized
dicts.
* ctf-open-bfd.c (ctf_bfdopen_ctfsect): Check for the flag: open the
symtab/strtab if not present, dynsym/dynstr otherwise.
* ctf-archive.c (ctf_arc_bufpreamble): New, get the preamble from
some arbitrary member of a CTF archive.
* ctf-impl.h (ctf_arc_bufpreamble): Declare it.
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The naming of the ctf_file_t type in libctf is a historical curiosity.
Back in the Solaris days, CTF dictionaries were originally generated as
a separate file and then (sometimes) merged into objects: hence the
datatype was named ctf_file_t, and known as a "CTF file". Nowadays, raw
CTF is essentially never written to a file on its own, and the datatype
changed name to a "CTF dictionary" years ago. So the term "CTF file"
refers to something that is never a file! This is at best confusing.
The type has also historically been known as a 'CTF container", which is
even more confusing now that we have CTF archives which are *also* a
sort of container (they contain CTF dictionaries), but which are never
referred to as containers in the source code.
So fix this by completing the renaming, renaming ctf_file_t to
ctf_dict_t throughout, and renaming those few functions that refer to
CTF files by name (keeping compatibility aliases) to refer to dicts
instead. Old users who still refer to ctf_file_t will see (harmless)
pointer-compatibility warnings at compile time, but the ABI is unchanged
(since C doesn't mangle names, and ctf_file_t was always an opaque type)
and things will still compile fine as long as -Werror is not specified.
All references to CTF containers and CTF files in the source code are
fixed to refer to CTF dicts instead.
Further (smaller) renamings of annoyingly-named functions to come, as
part of the process of souping up queries across whole archives at once
(needed for the function info and data object sections).
binutils/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* objdump.c (dump_ctf_errs): Rename ctf_file_t to ctf_dict_t.
(dump_ctf_archive_member): Likewise.
(dump_ctf): Likewise. Use ctf_dict_close, not ctf_file_close.
* readelf.c (dump_ctf_errs): Rename ctf_file_t to ctf_dict_t.
(dump_ctf_archive_member): Likewise.
(dump_section_as_ctf): Likewise. Use ctf_dict_close, not
ctf_file_close.
gdb/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* ctfread.c: Change uses of ctf_file_t to ctf_dict_t.
(ctf_fp_info::~ctf_fp_info): Call ctf_dict_close, not ctf_file_close.
include/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* ctf-api.h (ctf_file_t): Rename to...
(ctf_dict_t): ... this. Keep ctf_file_t around for compatibility.
(struct ctf_file): Likewise rename to...
(struct ctf_dict): ... this.
(ctf_file_close): Rename to...
(ctf_dict_close): ... this, keeping compatibility function.
(ctf_parent_file): Rename to...
(ctf_parent_dict): ... this, keeping compatibility function.
All callers adjusted.
* ctf.h: Rename references to ctf_file_t to ctf_dict_t.
(struct ctf_archive) <ctfa_nfiles>: Rename to...
<ctfa_ndicts>: ... this.
ld/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* ldlang.c (ctf_output): This is a ctf_dict_t now.
(lang_ctf_errs_warnings): Rename ctf_file_t to ctf_dict_t.
(ldlang_open_ctf): Adjust comment.
(lang_merge_ctf): Use ctf_dict_close, not ctf_file_close.
* ldelfgen.h (ldelf_examine_strtab_for_ctf): Rename ctf_file_t to
ctf_dict_t. Change opaque declaration accordingly.
* ldelfgen.c (ldelf_examine_strtab_for_ctf): Adjust.
* ldemul.h (examine_strtab_for_ctf): Likewise.
(ldemul_examine_strtab_for_ctf): Likewise.
* ldeuml.c (ldemul_examine_strtab_for_ctf): Likewise.
libctf/ChangeLog
2020-11-20 Nick Alcock <nick.alcock@oracle.com>
* ctf-impl.h: Rename ctf_file_t to ctf_dict_t: all declarations
adjusted.
(ctf_fileops): Rename to...
(ctf_dictops): ... this.
(ctf_dedup_t) <cd_id_to_file_t>: Rename to...
<cd_id_to_dict_t>: ... this.
(ctf_file_t): Fix outdated comment.
<ctf_fileops>: Rename to...
<ctf_dictops>: ... this.
(struct ctf_archive_internal) <ctfi_file>: Rename to...
<ctfi_dict>: ... this.
* ctf-archive.c: Rename ctf_file_t to ctf_dict_t.
Rename ctf_archive.ctfa_nfiles to ctfa_ndicts.
Rename ctf_file_close to ctf_dict_close. All users adjusted.
* ctf-create.c: Likewise. Refer to CTF dicts, not CTF containers.
(ctf_bundle_t) <ctb_file>: Rename to...
<ctb_dict): ... this.
* ctf-decl.c: Rename ctf_file_t to ctf_dict_t.
* ctf-dedup.c: Likewise. Rename ctf_file_close to
ctf_dict_close. Refer to CTF dicts, not CTF containers.
* ctf-dump.c: Likewise.
* ctf-error.c: Likewise.
* ctf-hash.c: Likewise.
* ctf-inlines.h: Likewise.
* ctf-labels.c: Likewise.
* ctf-link.c: Likewise.
* ctf-lookup.c: Likewise.
* ctf-open-bfd.c: Likewise.
* ctf-string.c: Likewise.
* ctf-subr.c: Likewise.
* ctf-types.c: Likewise.
* ctf-util.c: Likewise.
* ctf-open.c: Likewise.
(ctf_file_close): Rename to...
(ctf_dict_close): ...this.
(ctf_file_close): New trivial wrapper around ctf_dict_close, for
compatibility.
(ctf_parent_file): Rename to...
(ctf_parent_dict): ... this.
(ctf_parent_file): New trivial wrapper around ctf_parent_dict, for
compatibility.
* libctf.ver: Add ctf_dict_close and ctf_parent_dict.
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This commit follows on from the earlier commit "libctf, ld, binutils:
add textual error/warning reporting for libctf" and converts every error
in libctf that was reported using ctf_dprintf to use ctf_err_warn
instead, gettextizing them in the process, using N_() where necessary to
avoid doing gettext calls unless an error message is actually generated,
and rephrasing some error messages for ease of translation.
This requires a slight change in the ctf_errwarning_next API: this API
is public but has not been in a release yet, so can still change freely.
The problem is that many errors are emitted at open time (whether
opening of a CTF dict, or opening of a CTF archive): the former of these
throws away its incompletely-initialized ctf_file_t rather than return
it, and the latter has no ctf_file_t at all. So errors and warnings
emitted at open time cannot be stored in the ctf_file_t, and have to go
elsewhere.
We put them in a static local in ctf-subr.c (which is not very
thread-safe: a later commit will improve things here): ctf_err_warn with
a NULL fp adds to this list, and the public interface
ctf_errwarning_next with a NULL fp retrieves from it.
We need a slight exception from the usual iterator rules in this case:
with a NULL fp, there is nowhere to store the ECTF_NEXT_END "error"
which signifies the end of iteration, so we add a new err parameter to
ctf_errwarning_next which is used to report such iteration-related
errors. (If an fp is provided -- i.e., if not reporting open errors --
this is optional, but even if it's optional it's still an API change.
This is actually useful from a usability POV as well, since
ctf_errwarning_next is usually called when there's been an error, so
overwriting the error code with ECTF_NEXT_END is not very helpful!
So, unusually, ctf_errwarning_next now uses the passed fp for its
error code *only* if no errp pointer is passed in, and leaves it
untouched otherwise.)
ld, objdump and readelf are adapted to call ctf_errwarning_next with a
NULL fp to report open errors where appropriate.
The ctf_err_warn API also has to change, gaining a new error-number
parameter which is used to add the error message corresponding to that
error number into the debug stream when LIBCTF_DEBUG is enabled:
changing this API is easy at this point since we are already touching
all existing calls to gettextize them. We need this because the debug
stream should contain the errno's message, but the error reported in the
error/warning stream should *not*, because the caller will probably
report it themselves at failure time regardless, and reporting it in
every error message that leads up to it leads to a ridiculous chattering
on failure, which is likely to end up as ridiculous chattering on stderr
(trimmed a bit):
CTF error: `ld/testsuite/ld-ctf/A.c (0): lookup failure for type 3: flags 1: The parent CTF dictionary is unavailable'
CTF error: `ld/testsuite/ld-ctf/A.c (0): struct/union member type hashing error during type hashing for type 80000001, kind 6: The parent CTF dictionary is unavailable'
CTF error: `deduplicating link variable emission failed for ld/testsuite/ld-ctf/A.c: The parent CTF dictionary is unavailable'
ld/.libs/lt-ld-new: warning: CTF linking failed; output will have no CTF section: `The parent CTF dictionary is unavailable'
We only need to be told that the parent CTF dictionary is unavailable
*once*, not over and over again!
errmsgs are still emitted on warning generation, because warnings do not
usually lead to a failure propagated up to the caller and reported
there.
Debug-stream messages are not translated. If translation is turned on,
there will be a mixture of English and translated messages in the debug
stream, but rather that than burden the translators with debug-only
output.
binutils/ChangeLog
2020-08-27 Nick Alcock <nick.alcock@oracle.com>
* objdump.c (dump_ctf_archive_member): Move error-
reporting...
(dump_ctf_errs): ... into this separate function.
(dump_ctf): Call it on open errors.
* readelf.c (dump_ctf_archive_member): Move error-
reporting...
(dump_ctf_errs): ... into this separate function. Support
calls with NULL fp. Adjust for new err parameter to
ctf_errwarning_next.
(dump_section_as_ctf): Call it on open errors.
include/ChangeLog
2020-08-27 Nick Alcock <nick.alcock@oracle.com>
* ctf-api.h (ctf_errwarning_next): New err parameter.
ld/ChangeLog
2020-08-27 Nick Alcock <nick.alcock@oracle.com>
* ldlang.c (lang_ctf_errs_warnings): Support calls with NULL fp.
Adjust for new err parameter to ctf_errwarning_next. Only
check for assertion failures when fp is non-NULL.
(ldlang_open_ctf): Call it on open errors.
* testsuite/ld-ctf/ctf.exp: Always use the C locale to avoid
breaking the diags tests.
libctf/ChangeLog
2020-08-27 Nick Alcock <nick.alcock@oracle.com>
* ctf-subr.c (open_errors): New list.
(ctf_err_warn): Calls with NULL fp append to open_errors. Add err
parameter, and use it to decorate the debug stream with errmsgs.
(ctf_err_warn_to_open): Splice errors from a CTF dict into the
open_errors.
(ctf_errwarning_next): Calls with NULL fp report from open_errors.
New err param to report iteration errors (including end-of-iteration)
when fp is NULL.
(ctf_assert_fail_internal): Adjust ctf_err_warn call for new err
parameter: gettextize.
* ctf-impl.h (ctfo_get_vbytes): Add ctf_file_t parameter.
(LCTF_VBYTES): Adjust.
(ctf_err_warn_to_open): New.
(ctf_err_warn): Adjust.
(ctf_bundle): Used in only one place: move...
* ctf-create.c: ... here.
(enumcmp): Use ctf_err_warn, not ctf_dprintf, passing the err number
down as needed. Don't emit the errmsg. Gettextize.
(membcmp): Likewise.
(ctf_add_type_internal): Likewise.
(ctf_write_mem): Likewise.
(ctf_compress_write): Likewise. Report errors writing the header or
body.
(ctf_write): Likewise.
* ctf-archive.c (ctf_arc_write_fd): Use ctf_err_warn, not
ctf_dprintf, and gettextize, as above.
(ctf_arc_write): Likewise.
(ctf_arc_bufopen): Likewise.
(ctf_arc_open_internal): Likewise.
* ctf-labels.c (ctf_label_iter): Likewise.
* ctf-open-bfd.c (ctf_bfdclose): Likewise.
(ctf_bfdopen): Likewise.
(ctf_bfdopen_ctfsect): Likewise.
(ctf_fdopen): Likewise.
* ctf-string.c (ctf_str_write_strtab): Likewise.
* ctf-types.c (ctf_type_resolve): Likewise.
* ctf-open.c (get_vbytes_common): Likewise. Pass down the ctf dict.
(get_vbytes_v1): Pass down the ctf dict.
(get_vbytes_v2): Likewise.
(flip_ctf): Likewise.
(flip_types): Likewise. Use ctf_err_warn, not ctf_dprintf, and
gettextize, as above.
(upgrade_types_v1): Adjust calls.
(init_types): Use ctf_err_warn, not ctf_dprintf, as above.
(ctf_bufopen_internal): Likewise. Adjust calls. Transplant errors
emitted into individual dicts into the open errors if this turns
out to be a failed open in the end.
* ctf-dump.c (ctf_dump_format_type): Adjust ctf_err_warn for new err
argument. Gettextize. Don't emit the errmsg.
(ctf_dump_funcs): Likewise. Collapse err label into its only case.
(ctf_dump_type): Likewise.
* ctf-link.c (ctf_create_per_cu): Adjust ctf_err_warn for new err
argument. Gettextize. Don't emit the errmsg.
(ctf_link_one_type): Likewise.
(ctf_link_lazy_open): Likewise.
(ctf_link_one_input_archive): Likewise.
(ctf_link_deduplicating_count_inputs): Likewise.
(ctf_link_deduplicating_open_inputs): Likewise.
(ctf_link_deduplicating_close_inputs): Likewise.
(ctf_link_deduplicating): Likewise.
(ctf_link): Likewise.
(ctf_link_deduplicating_per_cu): Likewise. Add some missed
ctf_set_errnos to obscure error cases.
* ctf-dedup.c (ctf_dedup_rhash_type): Adjust ctf_err_warn for new
err argument. Gettextize. Don't emit the errmsg.
(ctf_dedup_populate_mappings): Likewise.
(ctf_dedup_detect_name_ambiguity): Likewise.
(ctf_dedup_init): Likewise.
(ctf_dedup_multiple_input_dicts): Likewise.
(ctf_dedup_conflictify_unshared): Likewise.
(ctf_dedup): Likewise.
(ctf_dedup_rwalk_one_output_mapping): Likewise.
(ctf_dedup_id_to_target): Likewise.
(ctf_dedup_emit_type): Likewise.
(ctf_dedup_emit_struct_members): Likewise.
(ctf_dedup_populate_type_mapping): Likewise.
(ctf_dedup_populate_type_mappings): Likewise.
(ctf_dedup_emit): Likewise.
(ctf_dedup_hash_type): Likewise. Fix a bit of messed-up error
status setting.
(ctf_dedup_rwalk_one_output_mapping): Likewise. Don't hide
unknown-type-kind messages (which signify file corruption).
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We gettextize under our package name, which we change to a more
reasonable 'libctf'. Our internationalization support is mostly
provided by ctf-intl.h, which is a copy of opcodes/opintl.h with
the non-gettext_noop N_() expansion debracketed to avoid pedantic
compiler warnings.
The libctf error strings returned by ctf_errmsg are marked up for
internationalization.
(We also adjust binutils's Makefile a tiny bit to allow for the
fact that libctf now uses functions from libintl.)
binutils/ChangeLog
2020-08-27 Nick Alcock <nick.alcock@oracle.com>
* Makefile.am (readelf_LDADD): Move $(LIBINTL) after $(LIBCTF_NOBFD).
* Makefile.in: Regenerated.
libctf/ChangeLog
2020-08-27 Nick Alcock <nick.alcock@oracle.com>
* configure.ac: Adjust package name to simply 'libctf': arbitrarily
declare this to be version 1.2.0.
* Makefile.am (AM_CPPFLAGS): Add @INCINTL@.
* Makefile.in: Regenerated.
* configure: Regenerated.
* ctf-intl.h: New file, lightly modified from opcodes/opintl.h.
* ctf-impl.h: Include it.
* ctf-error.r (_ctf_errlist_t): Mark strings as noop-translatable.
(ctf_errmsg): Actually translate them.
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This fairly intricate commit connects up the CTF linker machinery (which
operates in terms of ctf_archive_t's on ctf_link_inputs ->
ctf_link_outputs) to the deduplicator (which operates in terms of arrays
of ctf_file_t's, all the archives exploded).
The nondeduplicating linker is retained, but is not called unless the
CTF_LINK_NONDEDUP flag is passed in (which ld never does), or the
environment variable LD_NO_CTF_DEDUP is set. Eventually, once we have
confidence in the much-more-complex deduplicating linker, I hope the
nondeduplicating linker can be removed.
In brief, what this does is traverses each input archive in
ctf_link_inputs, opening every member (if not already open) and tying
child dicts to their parents, shoving them into an array and
constructing a corresponding parents array that tells the deduplicator
which dict is the parent of which child. We then call ctf_dedup and
ctf_dedup_emit with that array of inputs, taking the outputs that result
and putting them into ctf_link_outputs where the rest of the CTF linker
expects to find them, then linking in the variables just as is done by
the nondeduplicating linker.
It also implements much of the CU-mapping side of things. The problem
CU-mapping introduces is that if you map many input CUs into one output,
this is saying that you want many translation units to produce at most
one child dict if conflicting types are found in any of them. This
means you can suddenly have multiple distinct types with the same name
in the same dict, which libctf cannot really represent because it's not
something you can do with C translation units.
The deduplicator machinery already committed does as best it can with
these, hiding types with conflicting names rather than making child
dicts out of them: but we still need to call it. This is done similarly
to the main link, taking the inputs (one CU output at a time),
deduplicating them, taking the output and making it an input to the
final link. Two (significant) optimizations are done: we share atoms
tables between all these links and the final link (so e.g. all type hash
values are shared, all decorated type names, etc); and any CU-mapped
links with only one input (and no child dicts) doesn't need to do
anything other than renaming the CU: the CU-mapped link phase can be
skipped for it. Put together, large CU-mapped links can save 50% of
their memory usage and about as much time (and the memory usage for
CU-mapped links is significant, because all those output CUs have to
have all their types stored in memory all at once).
include/
* ctf-api.h (CTF_LINK_NONDEDUP): New, turn off the
deduplicator.
libctf/
* ctf-impl.h (ctf_list_splice): New.
* ctf-util.h (ctf_list_splice): Likewise.
* ctf-link.c (link_sort_inputs_cb_arg_t): Likewise.
(ctf_link_sort_inputs): Likewise.
(ctf_link_deduplicating_count_inputs): Likewise.
(ctf_link_deduplicating_open_inputs): Likewise.
(ctf_link_deduplicating_close_inputs): Likewise.
(ctf_link_deduplicating_variables): Likewise.
(ctf_link_deduplicating_per_cu): Likewise.
(ctf_link_deduplicating): Likewise.
(ctf_link): Call it.
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This adds the core deduplicator that the ctf_link machinery calls
(possibly repeatedly) to link the CTF sections: it takes an array
of input ctf_file_t's and another array that indicates which entries in
the input array are parents of which other entries, and returns an array
of outputs. The first output is always the ctf_file_t on which
ctf_link/ctf_dedup/etc was called: the other outputs are child dicts
that have the first output as their parent.
include/
* ctf-api.h (CTF_LINK_SHARE_DUPLICATED): No longer unimplemented.
libctf/
* ctf-impl.h (ctf_type_id_key): New, the key in the
cd_id_to_file_t.
(ctf_dedup): New, core deduplicator state.
(ctf_file_t) <ctf_dedup>: New.
<ctf_dedup_atoms>: New.
<ctf_dedup_atoms_alloc>: New.
(ctf_hash_type_id_key): New prototype.
(ctf_hash_eq_type_id_key): Likewise.
(ctf_dedup_atoms_init): Likewise.
* ctf-hash.c (ctf_hash_eq_type_id_key): New.
(ctf_dedup_atoms_init): Likewise.
* ctf-create.c (ctf_serialize): Adjusted.
(ctf_add_encoded): No longer static.
(ctf_add_reftype): Likewise.
* ctf-open.c (ctf_file_close): Destroy the
ctf_dedup_atoms_alloc.
* ctf-dedup.c: New file.
* ctf-decls.h [!HAVE_DECL_STPCPY]: Add prototype.
* configure.ac: Check for stpcpy.
* Makefile.am: Add it.
* Makefile.in: Regenerate.
* config.h.in: Regenerate.
* configure: Regenerate.
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Add a new debugging configure option, --enable-libctf-hash-debugging,
off by default, which lets you configure in expensive internal
consistency checks and enable the printing of debugging output when
LIBCTF_DEBUG=t before type deduplication has happened.
In this commit we just add the option and cause it to turn ctf_assert
into a real, hard assert for easier debugging.
libctf/
* configure.ac: Add --enable-libctf-hash-debugging.
* aclocal.m4: Pull in enable.m4, for GCC_ENABLE.
* Makefile.in: Regenerated.
* configure: Likewise.
* config.h.in: Likewise.
* ctf-impl.h [ENABLE_LIBCTF_HASH_DEBUGGING]
(ctf_assert): Define to assert.
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This very thin abstraction layer provides SHA-1ing facilities to all of
libctf, almost all inlined wrappers around the libiberty functionality
other than ctf_sha1_fini.
The deduplicator will use this to recursively hash types to prove their
identity.
libctf/
* ctf-sha1.h: New, inline wrappers around sha1_init_ctx and
sha1_process_bytes.
* ctf-impl.h: Include it.
(ctf_sha1_init): New.
(ctf_sha1_add): Likewise.
(ctf_sha1_fini): Likewise.
* ctf-sha1.c: New, non-inline wrapper around sha1_finish_ctx
producing strings.
* Makefile.am: Add file.
* Makefile.in: Regenerate.
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