This is a tricky one. BFD, on the linker's behalf, reports symbols to
libctf via the ctf_new_symbol and ctf_new_dynsym callbacks, which
ultimately call ctf_link_add_linker_symbol. But while this happens
after strtab offsets are finalized, it happens before the .dynstr is
actually laid out, so we can't iterate over it at this stage and
it is not clear what the reported symbols are actually called. So
a second callback, examine_strtab, is called after the .dynstr is
finalized, which calls ctf_link_add_strtab and ultimately leads
to ldelf_ctf_strtab_iter_cb being called back repeatedly until the
offsets of every string in the .dynstr is passed to libctf.
libctf can then use this to get symbol names out of the input (which
usually stores symbol types in the form of a name -> type mapping at
this stage) and extract the types of those symbols, feeding them back
into their final form as a 1:1 association with the real symtab's
STT_OBJ and STT_FUNC symbols (with a few skipped, see
ctf_symtab_skippable).
This representation is compact, but has one problem: if libctf somehow
gets confused about the st_type of a symbol, it'll stick an entry into
the function symtypetab when it should put it into the object
symtypetab, or vice versa, and *every symbol from that one on* will have
the wrong CTF type because it's actually looking up the type for a
different symbol.
And we have just such a bug. ctf_link_add_strtab was not taking the
refcounts of strings into consideration, so even strings that had been
eliminated from the strtab by virtue of being in objects eliminated via
--as-needed etc were being reported. This is harmful because it can
lead to multiple strings with the same apparent offset, and if the last
duplicate to be reported relates to an eliminated symbol, we look up the
wrong symbol from the input and gets its type wrong: if it's unlucky and
the eliminated symbol is also of the wrong st_type, we will end up with
a corrupted symtypetab.
Thankfully the wrong-st_type case is already diagnosed by a
this-can-never-happen paranoid warning:
CTF warning: Symbol 61a added to CTF as a function but is of type 1
or the converse
* CTF warning: Symbol a3 added to CTF as a data object but is of type 2
so at least we can tell when the corruption has spread to more than one
symbol's type.
Skipping zero-refcounted strings is easy: teach _bfd_elf_strtab_str to
skip them, and ldelf_ctf_strtab_iter_cb to loop over skipped strings
until it falls off the end or finds one that isn't skipped.
bfd/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* elf-strtab.c (_bfd_elf_strtab_str): Skip strings with zero refcount.
ld/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ldelfgen.c (ldelf_ctf_strtab_iter_cb): Skip zero-refcount strings.
libctf/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ctf-create.c (symtypetab_density): Report the symbol name as
well as index in the name != object error; note the likely
consequences.
* ctf-link.c (ctf_link_shuffle_syms): Report the symbol index
as well as name.
In the "no symbols" case (commonplace for executables), we were freeing
the ctf_dynsyms using free(), instead of ctf_dynhash_destroy(), leaking
a little memory.
(This is harmless in the common case of ld usage, but libctf might be
used by persistent processes too.)
libctf/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ctf-link.c (ctf_link_shuffle_syms): Free ctf_dynsyms properly.
Comparing an encoding's cte_bits to a ctf_type_size needs a cast:
one is a uint32_t and the other is an ssize_t.
libctf/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ctf-dump.c (ctf_dump_format_type): Fix signed/unsigned confusion.
A transient bug in the preceding change (fixed before commit) exposed a
new failure, of ld/testsuite/ld-ctf/diag-parname.d. This attempts to
ensure that if we link a dict with child type IDs but no attached
parent, we get a suitable ECTF_NOPARENT error. This was happening
before this commit, but only by chance, because ctf_variable_iter and
ctf_variable_next check to see if the dict they're passed is a child
dict without an associated parent. We forgot error-checking on the
ctf_variable_next call, and as a result this was concealed -- and
looking for the problem exposed a new bug.
If any of the lookups beneath ctf_dedup_hash_type fail, the CTF link
does *not* fail, but acts quite bizarrely, skipping the type but
emitting an error to the CTF error/warning log -- so the linker will
report an error, emit a partial CTF dict missing some types, and exit
with exitcode 0 as if nothing went wrong. Since ctf_dedup_hash_type is
never expected to fail in normal operation, this is surely wrong:
failures at emission time do not emit partial CTF dicts, so failures
at hashing time should not either.
So propagate the error back up.
Also fix a couple of smaller bugs where we fail to properly free things
and/or propagate error codes on various rare link-time errors and
out-of-memory conditions.
libctf/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ctf-dedup.c (ctf_dedup): Pass on errors from ctf_dedup_hash_type.
Call ctf_dedup_fini properly on other errors.
(ctf_dedup_emit_type): Set the errno on dynhash insertion failure.
* ctf-link.c (ctf_link_deduplicating_per_cu): Close outputs beyond
output 0 when asserting because >1 output is found.
(ctf_link_deduplicating): Likewise, when asserting because the
shared output is not the same as the passed-in fp.
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.
There is no such thing, and the comment makes no sense, and doesn't
match what the code is doing. We always want to put variables in the
same dicts as the types they relate to if at all possible.
libctf/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ctf-link.c (ctf_link_one_variable): Remove reference to
"unconflicted link mode".
The nondeduplicating CTF linker was kept around when the deduplicating
one was added so that people had something to fall back to in case the
deduplicating linker turned out to be buggy. It's now much more stable
than the nondeduplicating linker, in addition to much faster, using much
less memory and producing much better output. In addition, while
libctf has a linker flag to invoke the nondeduplicating linker, ld does
not expose it: the only way to turn it on within ld is an intentionally-
undocumented environment variable. So we can remove it without any ABI
or user-visibility concerns (the only thing we leave around is the
CTF_LINK_NONDEDUP flag, which can easily be interpreted as "deduplicate
less", though right now it does nothing).
This lets us remove a lot of complexity associated with tracking
filenames and CU names separately (something the deduplcating linker
never bothered with, since the cunames are always reliable and ld never
hands us useful filenames anyway)
The biggest lacuna left behind is the ctf_type_mapping machinery, which
slows down deduplicating links quite a lot. We can't just ditch it
because ctf_add_type uses it: removing the slowdown from the
deduplicating linker is a job for another commit.
include/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ctf-api.h (CTF_LINK_SHARE_DUPLICATED): Note that this might
merely change how much deduplication is done.
libctf/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ctf-link.c (ctf_create_per_cu): Drop FILENAME now that it is
always identical to CUNAME.
(ctf_link_deduplicating_one_symtypetab): Adjust.
(ctf_link_one_type): Remove.
(ctf_link_one_input_archive_member): Likewise.
(ctf_link_close_one_input_archive): Likewise.
(ctf_link_one_input_archive): Likewise.
(ctf_link): No longer call it. Drop CTF_LINK_NONDEDUP path.
Improve header comment a bit (dicts, not files). Adjust
ctf_create_per_cu call.
(ctf_link_deduplicating_variables): Simplify.
(ctf_link_in_member_cb_arg_t) <cu_name>: Remove.
<in_input_cu_file>: Likewise.
<in_fp_parent>: Likewise.
<done_parent>: Likewise.
(ctf_link_one_variable): Turn uses of in_file_name to in_cuname.
Ever since the generator-style _next iterators were introduced, there
have been separate implementations of the functional-style _iter
iterators that do the same thing as _next.
This is annoying and adds more dependencies on the internal guts of the
file format. Rip them all out and replace them with the corresponding
_next iterators. Only ctf_archive_raw_iter and ctf_label_iter survive,
the former because there is no access to the raw binary data of archives
via any _next iterator, and the latter because ctf_label_next hasn't
been implemented (because labels are currently not used for anything).
Tested by reverting the change (already applied) that reimplemented
ctf_member_iter in terms of ctf_member_next, then verifying that the
_iter and _next iterators produced the same results for every iterable
entity within a large type archive.
libctf/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ctf-types.c (ctf_member_iter): Move 'rc' to an inner scope.
(ctf_enum_iter): Reimplement in terms of ctf_enum_next.
(ctf_type_iter): Reimplement in terms of ctf_type_next.
(ctf_type_iter_all): Likewise.
(ctf_variable_iter): Reimplement in terms of ctf_variable_next.
* ctf-archive.c (ctf_archive_iter_internal): Remove.
(ctf_archive_iter): Reimplement in terms of ctf_archive_next.
The top level of CTF containers is a "CTF archive", which contains a
collection of named members (each a CTF dictionary). In the serialized
file format, this is optional and skipped if the archive would have only
one member, as when no ambiguous types are present: so it is commonplace
to have a simple ctf_dict_t written out, with no archive container
wrapped around it.
But, unlike ctf_archive_iter, ctf_archive_next didn't quite handle this
case right. It should set the name of this fake "member" to
_CTF_SECTION, i.e. ".ctf", but it was failing to do so, so callers got
an unintialized variable back instead and were understandably confused.
So set the name properly.
libctf/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ctf-archive.c (ctf_archive_next): Set the name of parents in
single-member archives.
AC_CANONICAL_TARGET is needed for @target@ substitution in the
makefile. AC_CANONICAL_HOST and AC_CANONICAL_BUILD are alread invoked
indirectly, make them explicit.
* configure.ac: Invoke AC_CANONICAL_TARGET, AC_CANONICAL_HOST
and AC_CANONICAL_BUILD.
* configure: Regenerate.
* Makefile.in: Regenerate.
I'm dividing this into three groups for now: new features, bugfixes,
and bugfixes also present on a stable branch.
Only user-visible bugfixes, not build-system fixes, are listed.
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.
Without this, GCC warns:
In file included from conftest.c:36:
../../libctf/../bfd/elf-bfd.h: In function 'bfd_section_is_ctf':
../../libctf/../bfd/elf-bfd.h:3089:10: warning: implicit declaration of function 'strncmp' [-Wimplicit-function-declaration]
3089 | return strncmp (name, ".ctf", 4) == 0 && (name[4] == 0 || name[4] == '.');
| ^~~~~~~
../../libctf/../bfd/elf-bfd.h:3089:33: warning: 'strncmp' argument 3 type is 'int' where 'long unsigned int' is expected in a call to built-in function declared without prototype [-Wbuiltin-declaration-mismatch]
3089 | return strncmp (name, ".ctf", 4) == 0 && (name[4] == 0 || name[4] == '.');
| ^
<built-in>: note: built-in 'strncmp' declared here
These warnings do not currently throw off the result of the configure
check, but it's better to squash them anyway.
libctf/ChangeLog
2021-02-03 Nick Alcock <nick.alcock@oracle.com>
* configure.ac (ac_cv_libctf_bfd_elf): Include string.h.
* configure: Regenerated.
The run_native_host_cmd implementation in testsuite/lib/ctf-lib.exp
uses try/catch, which are new in Tcl 8.6. Require a Tcl that knows
that try exists, as suggested by Jan Beulich.
libctf/ChangeLog
2021-02-03 Nick Alcock <nick.alcock@oracle.com>
* configure.ac (EXPECT): Check for, in order to define...
(TCL_TRY): ... this, if Tcl supports try/catch.
* Makefile.am (TCL_TRY): Run the testsuite only if set.
* configure: Regenerated.
* Makefile.in: Likewise.
Right now, these libraries hardwire -L../intl -lintl on a few fixed
platforms, which works fine on those platforms but on other platforms
leads to shared libraries that lack libintl_* symbols when configured
--with-included-gettext, and/or static libraries that contain libintl as
*another* static library. If we instead use the LIBINTL variable
defined in ../intl/config.intl, this gives us the right thing on all
three classes of platform (gettext in libc, gettext in system libintl,
gettext in ../intl/libintl.a).. This also means we can rip out some
Darwin-specific machinery from configure.ac and also simplify the Cygwin
side.
This also means that the libctf testsuite (and other places that include
libbfd, libopcodes or libctf) don't need to grow libintl dependencies
just on account of those libraries (though they still need such
dependencies if they themselves use gettext machinery).
bfd/ChangeLog
2021-02-03 Nick Alcock <nick.alcock@oracle.com>
* configure.ac (SHARED_LIBADD): Remove explicit -lintl population in
favour of LIBINTL.
* configure: Regenerated.
libctf/ChangeLog
2021-02-02 Nick Alcock <nick.alcock@oracle.com>
* configure.ac (CTF_LIBADD): Remove explicit -lintl population in
favour of LIBINTL.
* Makefile.am (libctf_nobfd_la_LIBADD): No longer explicitly
include $(LIBINTL).
(check-DEJAGNU): Pass down to tests as well.
* configure: Regenerated.
* Makefile.in: Likewise.
opcodes/ChangeLog
2021-02-04 Nick Alcock <nick.alcock@oracle.com>
* configure.ac (SHARED_LIBADD): Remove explicit -lintl population in
favour of LIBINTL.
* configure: Regenerated.
The ctf_type_name_raw and ctf_type_aname_raw functions, which return the
raw, unadorned name of CTF types, have one unfortunate wrinkle: they
return NULL not only on error but when returning the name of types
without a name in writable dicts. This was unintended: it not only
makes it impossible to reliably tell if a given call to
ctf_type_name_raw failed (due to a bad string offset say), but also
complicates all its callers, who now have to check for both NULL and "".
The written-out form of CTF has no concept of a NULL pointer instead of
a string: all null strings are strtab offset 0, "". So the more we can
do to remove this distinction from the writable form, the less complex
the rest of our code needs to be.
Armour against NULL in multiple places, arranging to return "" from
ctf_type_name_raw if offset 0 is passed in, and removing a risky
optimization from ctf_str_add* that avoided doing anything if a NULL was
passed in: this added needless irregularity to the functions' API
surface, since "" and NULL should be treated identically, and in the
case of ctf_str_add_ref, we shouldn't skip adding the passed-in REF to
the list of references to be updated no matter what the content of the
string happens to be.
This means we can simplify the deduplicator a tiny bit, also fixing a
bug (latent when used by ld) where if the input dict was writable,
we failed to realise when types were nameless and could end up creating
deeply unhelpful synthetic forwards with no name, which we just banned
a few commits ago, so the link failed.
libctf/ChangeLog
2021-01-27 Nick Alcock <nick.alcock@oracle.com>
* ctf-string.c (ctf_str_add): Treat adding a NULL as adding "".
(ctf_str_add_ref): Likewise.
(ctf_str_add_external): Likewise.
* ctf-types.c (ctf_type_name_raw): Always return "" for offset 0.
* ctf-dedup.c (ctf_dedup_multiple_input_dicts): Don't armour
against NULL name.
(ctf_dedup_maybe_synthesize_forward): Likewise.
We declare a variable to hold errors at two scopes, and then initialize
the inner one and jump to a scope where only the outer one is in scope.
The consequences are minor: only the version of the error message
printed in the debugging stream is impacted.
libctf/ChangeLog
2021-01-27 Nick Alcock <nick.alcock@oracle.com>
* ctf-create.c (ctf_serialize): Fix shadowing.
Now that "anonymous typedef nodes" have been extirpated, we can mandate
that things that have names in C must have names in CTF too. (Unlike
the no-forwards embarrassment, the deduplicator does nothing special
with names: types that have names in C will have the same name in CTF.
So we can assume that the CTF rules and the C rules are the same.)
include/ChangeLog
2021-01-27 Nick Alcock <nick.alcock@oracle.com>
* ctf-api.h (ECTF_NONAME): New.
(ECTF_NERR): Adjust.
libctf/ChangeLog
2021-01-27 Nick Alcock <nick.alcock@oracle.com>
* ctf-create.c (ctf_add_encoded): Add check for non-empty name.
(ctf_add_forward): Likewise.
(ctf_add_typedef): Likewise.
There is special code in libctf to handle typedefs with no name, which
the code calls "anonymous typedef nodes".
These monsters are obviously not something C programs can include: the
whole point of a ttypedef is to introduce a new name. Looking back at
the history of DWARF in GCC, the only thing (outside C++ anonymous
namespaces) which can generate a DW_TAG_typedef without a DW_AT_name is
obsolete code to handle the long-removed -feliminate-dwarf2-dups option.
Looking at OpenSolaris, typedef nodes with no name couldn't be generated
by the DWARF->CTF converter at all (and its deduplicator barfed on
them): the only reason for the existence of this code is a special case
working around a peculiarity of stabs whereby types could sometimes be
referenced before they were introduced.
We don't need to carry code in libctf to handle special cases in an
obsolete OpenSolaris converter (that yields a format that isn't readable
by libctf anyway). So drop it.
libctf/ChangeLog
2021-01-27 Nick Alcock <nick.alcock@oracle.com>
* ctf-open.c (init_types): Rip out code to check anonymous typedef
nodes.
* ctf-create.c (ctf_add_reftype): Likewise.
* ctf-lookup.c (refresh_pptrtab): Likewise.
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.
Our recent commit to support unnamed structure members better ditched
the old ctf_member_iter iterator body in favour of ctf_member_next.
However, these functions treat unnamed structure members differently:
ctf_member_iter just returned whatever the internal representation
contained, while ctf_member_next took care to always return "" rather
than sometimes returning "" and sometimes NULL depending on whether the
dict was dynamic (a product of ctf_create) or not (a product of
ctf_open). After this commit, ctf_member_iter did the same.
It was always a bug for external callers not to treat a "" return from
these functions as if it were NULL, so only buggy callers could be
affected -- but one of those buggy callers was ctf_add_type, which
assumed that it could just take whatever name was returned from
ctf_member_iter and slam it directly into the internal representation of
a dynamic dict -- which expects NULL for unnamed members, not "". The
net effect of all of this is that taking a struct containing unnamed
members and ctf_add_type'ing it into a dynamic dict produced a dict
whose unnamed members were inaccessible to ctf_member_info (though if
you wrote that dict out and then ctf_open'ed it, they would magically
reappear again).
Compensate for this by suitably transforming a "" name into NULL in the
internal representation, as should have been done all along.
libctf/ChangeLog
2021-01-19 Nick Alcock <nick.alcock@oracle.com>
* ctf-create.c (membadd): Transform ""-named members into
NULL-named ones.
* testsuite/libctf-regression/type-add-unnamed-struct*: New test.
The recent work allowing lookups of pointers in child dicts when the
pointed-to type is in the parent dict broke the case where a pointer
type that does not exist at all is looked up: we mistakenly return the
pointed-to type, which is likely not a pointer at all. This causes
considerable confusion.
Fixed, with a new testcase.
libctf/ChangeLog
2021-01-19 Nick Alcock <nick.alcock@oracle.com>
* ctf-lookup.c (ctf_lookup_by_name_internal): Do not return the
base type if looking up a nonexistent pointer type.
* testsuite/libctf-regression/pptrtab*: Test it.
commit f478212851 did the regen by hand, missed a change in
ld/configure and didn't update line numbers. Fix that, and an old
regen of ld/Makefile.in with the wrong automake.
bfd/
* configure: Regenerate.
binutils/
* configure: Regenerate.
gas/
* configure: Regenerate.
gprof/
* configure: Regenerate.
ld/
* Makefile.in: Regenerate.
* configure: Regenerate.
libctf/
* configure: Regenerate.
opcodes/
* configure: Regenerate.
zlib/
* configure: Regenerate.
This returns an int, not a long int or an ssize_t (as one test was
inconsistently assuming).
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* testsuite/libctf-lookup/struct-iteration.c (main):
ctf_member_count returns an int.
We never actually check to see if the compiler supports CTF,
or even if a suitable compiler exists.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* Makefile.am (BASEDIR): New.
(BFDDIR): Likewise.
(check-DEJAGNU): Add development.exp to prerequisites.
(development.exp): New.
(CONFIG_STATUS_DEPENDENCIES): New.
(EXTRA_DEJAGNU_SITE_CONFIG): Likewise.
(DISTCLEANFILES): Likewise.
* Makefile.in: Regenerated.
* testsuite/lib/ctf-lib.exp (check_ctf_available): Return boolean.
* testsuite/libctf-lookup/lookup.exp: Call check_ctf_available.
* testsuite/libctf-regression/regression.exp: Likewise.
The type printer was unconditionally printing these as if they were
forwards to structs, even if they were forwards to unions or enums.
ld/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* testsuite/ld-ctf/enum-forward.c: New test.
* testsuite/ld-ctf/enum-forward.c: New results.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* ctf-types.c (ctf_type_aname): Print forwards to unions and enums
properly.
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.
Parent dicts are nowadays imported automatically in most situations, so
the comment in ctf_archive_iter warning people that they need to import
parents by hand is wrong. Remove it.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* ctf-archive.c (ctf_archive_iter): Remove outdated comment.
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.
In the last cycle there have been various changes that have replaced
parts of the CTF format with other parts without format
compatibility. This was not a compat break, because the old format was
never accepted by any version of libctf (the not-in-official-release CTF
compiler patch was emitting an invalid func info section), but
nonetheless it can confuse users using that patch if they link together
object files and find the func info sections in the inputs silently
disappearing.
Scan the linker inputs for this problem and emit a warning if any are
found.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* ctf-link.c (ctf_link_warn_outdated_inputs): New.
(ctf_link_write): Call it.
I had reports that this doesn't work. This test shows it working (and
also shows how annoying it is to do symbol lookup by name with the
present API: we need a ctf_arc_lookup_symbol_name for users that don't
already have a symtab handy).
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* testsuite/libctf-lookup/enum-symbol.lk: New symbol-lookup test.
* testsuite/libctf-lookup/enum-symbol-ctf.c: New CTF input.
* testsuite/libctf-lookup/enum-symbol.c: New lookup test.
This introduces a new lookup testsuite under libctf, which operates by
compiling (with libtool) a "lookup" .c file that uses libctf to analyze
some other program, then compiling some number of test object files with
CTF and optionally linking them together and running the lookup program
on the test object files (or linked test binary), before diffing the
result much as run_dump_test does.
This lets us test the portions of libctf that are not previously
testable, notably the portions that do lookup on linked output and
that create dynamic dictionaries and then do lookup on them before
writing them out, something that is not tested by the ld-ctf testsuite
because the linker never does this.
A couple of simple tests are added: one testing the functionality of
enum lookups, and one testing that the recently-added commit adding
extra paranoia to incomplete type handling doesn't break linking and
that the result of the link is an (otherwise-impossible) array of
forward type in the shared CTF dict.
ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* Makefile.def (libctf): No longer no_check. Checking depends on
all-ld.
* Makefile.in: Regenerated.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* Makefile.am (EXPECT): New.
(RUNTEST): Likewise.
(RUNTESTFLAGS): Likewise.
(CC_FOR_TARGET): Likewise.
(check-DEJAGNU): Likewise.
(AUTOMAKE_OPTIONS): Add dejagnu.
* Makefile.in: Regenerated.
* testsuite/config/default.exp: New.
* testsuite/lib/ctf-lib.exp: Likewise.
* testsuite/libctf-lookup/enum.lk: New test.
* testsuite/libctf-lookup/enum-ctf.c: New CTF input.
* testsuite/libctf-lookup/enum.c: New lookup test.
* testsuite/libctf-lookup/ambiguous-struct*.c: New test.
* testsuite/libctf-lookup/lookup.exp: New.
This complex morass inherited from libopcodes, which endeavours to
implement the effect of specifying ../bfd/libbfd.la in _LIBADD without
actually doing so, appears to be working around a libtool bug which as
far as I can see is no longer present (i.e., the install directory no
longer appears in -L arguments in libtool link-mode invocations, so
there is no danger of picking up old libbfds or other dependent
libraries).
Replaced with a simple reference to libbfd.la in the appropriate place.
Also adjusted things a little more so that libctf.la and libctf-nobfd.la
are self-contained, even when linking statically. This opens up the
possibility of running libtool to link against libctf from inside the
(upcoming) testsuite.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* configure.ac (BFD_LIBADD): Remove.
(BFD_DEPENDENCIES): Likewise. Remove associated cases.
(SHARED_LIBADD): Rename to...
(CTF_LIBADD): ... this. Stick in a suitable libiberty even when
linking statically.
* Makefile.am (libctf_nobfd_la_LIBADD): Adjust accordingly.
libctf uses libintl.
(libctf_la_LIBADD): Reference libbfd.la directly, not via
BFD_LIBADD.
(libctf_la_DEPENDENCIES): Remove.
* Makefile.in: Regenerate.
* configure: Likewise.
This commit adds dumping of enumerands in this general form:
0x3: (kind 8) enum eleven_els (size 0x4) (aligned at 0x4)
ELEVEN_ONE: 10
ELEVEN_TWO: 11
ELEVEN_THREE: -256
ELEVEN_FOUR: -255
ELEVEN_FIVE: -254
...
ELEVEN_SEVEN: -252
ELEVEN_EIGHT: -251
ELEVEN_NINE: -250
ELEVEN_TEN: -249
ELEVEN_ELEVEN: -248
The first and last enumerands in the enumerated type are printed so that
you can tell if they've been cut off at one end or the other. (For now,
there is no way to control how many enumerands are printed.)
The dump output in general is improved, from this sort of thing a few
days ago:
4c: char [0x0:0x8] (size 0x1)
[0x0] (ID 0x4c) (kind 1) char:8 (aligned at 0x1, format 0x3, offset:bits 0x0:0x8)
4d: char * (size 0x8) -> 4c: char [0x0:0x8] (size 0x1)
[0x0] (ID 0x4d) (kind 3) char * (aligned at 0x8)
[...]
5a: struct _IO_FILE (size 0xd8)
[0x0] (ID 0x5a) (kind 6) struct _IO_FILE (aligned at 0x4)
[0x0] (ID 0x3) (kind 1) int _flags:32 (aligned at 0x4, format 0x1, offset:bits 0x0:0x20)
[0x40] (ID 0x4d) (kind 3) char * _IO_read_ptr (aligned at 0x8)
[0x80] (ID 0x4d) (kind 3) char * _IO_read_end (aligned at 0x8)
[0xc0] (ID 0x4d) (kind 3) char * _IO_read_base (aligned at 0x8)
5b: __FILE (size 0xd8) -> 5a: struct _IO_FILE (size 0xd8)
[0x0] (ID 0x5b) (kind 10) __FILE (aligned at 0x4)
[0x0] (ID 0x3) (kind 1) int _flags:32 (aligned at 0x4, format 0x1, offset:bits 0x0:0x20)
[0x40] (ID 0x4d) (kind 3) char * _IO_read_ptr (aligned at 0x8)
[0x80] (ID 0x4d) (kind 3) char * _IO_read_end (aligned at 0x8)
[0xc0] (ID 0x4d) (kind 3) char * _IO_read_base (aligned at 0x8)
[...]
406: struct coff_link_hash_entry (size 0x60)
[0x0] (ID 0x406) (kind 6) struct coff_link_hash_entry (aligned at 0x8)
[0x0] (ID 0x2b3) (kind 6) struct bfd_link_hash_entry root (aligned at 0x8)
[0x0] (ID 0x1d6) (kind 6) struct bfd_hash_entry root (aligned at 0x8)
[0x0] (ID 0x1d7) (kind 3) struct bfd_hash_entry * next (aligned at 0x8)
[0x40] (ID 0x61) (kind 3) const char * string (aligned at 0x8)
[0x80] (ID 0x1) (kind 1) long unsigned int hash:64 (aligned at 0x8, format 0x0, offset:bits 0x0:0x40)
[0xc0] (ID 0x397) (kind 8) enum bfd_link_hash_type type:8 (aligned at 0x1, format 0x0, offset:bits 0x0:0x8)
[0xc8] (ID 0x1c7) (kind 1) unsigned int non_ir_ref_regular:1 (aligned at 0x1, format 0x0, offset:bits 0x8:0x1)
[0xc9] (ID 0x1c8) (kind 1) unsigned int non_ir_ref_dynamic:1 (aligned at 0x1, format 0x0, offset:bits 0x9:0x1)
[0xca] (ID 0x1c9) (kind 1) unsigned int linker_def:1 (aligned at 0x1, format 0x0, offset:bits 0xa:0x1)
[0xcb] (ID 0x1ca) (kind 1) unsigned int ldscript_def:1 (aligned at 0x1, format 0x0, offset:bits 0xb:0x1)
[0xcc] (ID 0x1cb) (kind 1) unsigned int rel_from_abs:1 (aligned at 0x1, format 0x0, offset:bits 0xc:0x1)
... to this:
0x4c: (kind 1) char (format 0x3) (size 0x1) (aligned at 0x1)
0x4d: (kind 3) char * (size 0x8) (aligned at 0x8) -> 0x4c: (kind 1) char (format 0x3) (size 0x1) (aligned at 0x1)
0x5a: (kind 6) struct _IO_FILE (size 0xd8) (aligned at 0x4)
[0x0] _flags: ID 0x3: (kind 1) int (format 0x1) (size 0x4) (aligned at 0x4)
[0x40] _IO_read_ptr: ID 0x4d: (kind 3) char * (size 0x8) (aligned at 0x8)
[0x80] _IO_read_end: ID 0x4d: (kind 3) char * (size 0x8) (aligned at 0x8)
[0xc0] _IO_read_base: ID 0x4d: (kind 3) char * (size 0x8) (aligned at 0x8)
[0x100] _IO_write_base: ID 0x4d: (kind 3) char * (size 0x8) (aligned at 0x8)
0x5b: (kind 10) __FILE (size 0xd8) (aligned at 0x4) -> 0x5a: (kind 6) struct _IO_FILE (size 0xd8) (aligned at 0x4)
[...]
0x406: (kind 6) struct coff_link_hash_entry (size 0x60) (aligned at 0x8)
[0x0] root: ID 0x2b3: (kind 6) struct bfd_link_hash_entry (size 0x38) (aligned at 0x8)
[0x0] root: ID 0x1d6: (kind 6) struct bfd_hash_entry (size 0x18) (aligned at 0x8)
[0x0] next: ID 0x1d7: (kind 3) struct bfd_hash_entry * (size 0x8) (aligned at 0x8)
[0x40] string: ID 0x61: (kind 3) const char * (size 0x8) (aligned at 0x8)
[0x80] hash: ID 0x1: (kind 1) long unsigned int (format 0x0) (size 0x8) (aligned at 0x8)
[0xc0] type: ID 0x397: (kind 8) enum bfd_link_hash_type (format 0x7f2e) (size 0x1) (aligned at 0x1)
[0xc8] non_ir_ref_regular: ID 0x1c7: (kind 1) unsigned int:1 [slice 0x8:0x1] (format 0x0) (size 0x1) (aligned at 0x1)
[0xc9] non_ir_ref_dynamic: ID 0x1c8: (kind 1) unsigned int:1 [slice 0x9:0x1] (format 0x0) (size 0x1) (aligned at 0x1)
[0xca] linker_def: ID 0x1c9: (kind 1) unsigned int:1 [slice 0xa:0x1] (format 0x0) (size 0x1) (aligned at 0x1)
[0xcb] ldscript_def: ID 0x1ca: (kind 1) unsigned int:1 [slice 0xb:0x1] (format 0x0) (size 0x1) (aligned at 0x1)
[0xcc] rel_from_abs: ID 0x1cb: (kind 1) unsigned int:1 [slice 0xc:0x1] (format 0x0) (size 0x1) (aligned at 0x1)
[...]
In particular, indented subsections are only present for actual structs
and unions, not forwards to them, and the structure itself doesn't add a
spurious level of indentation; structure field names are easier to spot
(at the cost of not making them look so much like C field declarations
any more, but they weren't always shown in valid decl syntax even before
this change) the size, type kind, and alignment are shown for all types
for which they are meaningful; bitfield info is only shown for actual
bitfields within structures and not ordinary integral fields; and type
IDs are never omitted. Type printing is in general much more consistent
and there is much less duplicated code in the type dumper.
There is one user-visible effect outside the dumper: ctf_type_(a)name
was erroneously emitting a trailing space on the name of slice types,
even though a slice of an int and an int with the corresponding encoding
represent the same type and should have the same print form. This
trailing space is now gone.
ld/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* testsuite/ld-ctf/array.d: Adjust for dumper changes.
* testsuite/ld-ctf/conflicting-cycle-1.B-1.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-1.B-2.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-1.parent.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-2.A-1.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-2.A-2.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-2.parent.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-3.C-1.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-3.C-2.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-3.parent.d: Likewise.
* testsuite/ld-ctf/conflicting-enums.d: Likewise.
* testsuite/ld-ctf/conflicting-typedefs.d: Likewise.
* testsuite/ld-ctf/cross-tu-cyclic-conflicting.d: Likewise.
* testsuite/ld-ctf/cross-tu-cyclic-nonconflicting.d: Likewise.
* testsuite/ld-ctf/cross-tu-into-cycle.d: Likewise.
* testsuite/ld-ctf/cross-tu-noncyclic.d: Likewise.
* testsuite/ld-ctf/cycle-1.d: Likewise.
* testsuite/ld-ctf/cycle-2.A.d: Likewise.
* testsuite/ld-ctf/cycle-2.B.d: Likewise.
* testsuite/ld-ctf/cycle-2.C.d: Likewise.
* testsuite/ld-ctf/data-func-conflicted.d: Likewise.
* testsuite/ld-ctf/diag-cttname-null.d: Likewise.
* testsuite/ld-ctf/diag-cuname.d: Likewise.
* testsuite/ld-ctf/diag-parlabel.d: Likewise.
* testsuite/ld-ctf/diag-wrong-magic-number-mixed.d: Likewise.
* testsuite/ld-ctf/forward.d: Likewise.
* testsuite/ld-ctf/function.d: Likewise.
* testsuite/ld-ctf/slice.d: Likewise.
* testsuite/ld-ctf/super-sub-cycles.d: Likewise.
* testsuite/ld-ctf/enums.c: New test.
* testsuite/ld-ctf/enums.d: New test.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* ctf-decl.c (ctf_decl_push): Exclude slices from the decl stack.
* ctf-types.c (ctf_type_aname): No longer deal with slices here.
* ctf-dump.c (ctf_dump_membstate_t) <cdm_toplevel_indent>: Constify.
(CTF_FT_REFS): New.
(CTF_FT_BITFIELD): Likewise.
(CTF_FT_ID): Likewise.
(ctf_dump_member): Do not do indentation here. Migrate the
type-printing parts of this into...
(ctf_dump_format_type): ... here, to be shared by all type printers.
Get the errno value for non-representable types right. Do not print
bitfield info for non-bitfields. Improve the format and indentation
of other type output. Shuffle spacing around to make all indentation
either 'width of column' or 4 chars.
(ctf_dump_label): Pass CTF_FT_REFS to ctf_dump_format_type.
(ctf_dump_objts): Likewise. Spacing shuffle.
(ctf_dump_var): Likewise.
(type_hex_digits): Migrate down in the file, to above its new user.
(ctf_dump_type): Indent here instead. Pass CTF_FT_REFS to
ctf_dump_format_type. Don't trim off excess linefeeds now we no
longer generate them. Dump enumerated types.
C allows you to do only a very few things with entities of incomplete
type (as opposed to pointers to them): make pointers to them and give
them cv-quals, roughly. In particular you can't sizeof them and you
can't get their alignment.
We cannot impose all the requirements the standard imposes on CTF users,
because the deduplicator can transform any structure type into a forward
for the purposes of breaking cycles: so CTF type graphs can easily
contain things like arrays of forward type (if you want to figure out
their size or alignment, you need to chase down the types this forward
might be a forward to in child TU dicts: we will soon add API functions
to make doing this much easier).
Nonetheless, it is still meaningless to ask for the size or alignment of
forwards: but libctf didn't prohibit this and returned nonsense from
internal implementation details when you asked (it returned the kind of
the pointed-to type as both the size and alignment, because forwards
reuse ctt_type as a type kind, and ctt_type and ctt_size overlap). So
introduce a new error, ECTF_INCOMPLETE, which is returned when you try
to get the size or alignment of forwards: we also return it when you try
to do things that require libctf itself to get the size or alignment of
a forward, notably using a forward as an array index type (which C
should never do in any case) or adding forwards to structures without
specifying their offset explicitly.
The dumper will not emit size or alignment info for forwards any more.
(This should not be an API break since ctf_type_size and ctf_type_align
could both return errors before now: any code that isn't expecting error
returns is already potentially broken.)
include/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* ctf-api.h (ECTF_INCOMPLETE): New.
(ECTF_NERR): Adjust.
ld/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* testsuite/ld-ctf/conflicting-cycle-1.parent.d: Adjust for dumper
changes.
* testsuite/ld-ctf/cross-tu-cyclic-conflicting.d: Likewise.
* testsuite/ld-ctf/forward.c: New test...
* testsuite/ld-ctf/forward.d: ... and results.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* ctf-types.c (ctf_type_resolve): Improve comment.
(ctf_type_size): Yield ECTF_INCOMPLETE when applied to forwards.
Emit errors into the right dict.
(ctf_type_align): Likewise.
* ctf-create.c (ctf_add_member_offset): Yield ECTF_INCOMPLETE
when adding a member without explicit offset when this member, or
the previous member, is incomplete.
* ctf-dump.c (ctf_dump_format_type): Do not try to print the size of
forwards.
(ctf_dump_member): Do not try to print their alignment.
Dump more details about the types found in data object and function info
sections (the type ID and recursive info on the type itself, but not on
its members). Before now, this was being dumped for entries in the
variable section, but not for the closely-related function info and data
object sections, which is inconsistent and makes finding the
corresponding types in the type section unnecessarily hard. (This also
gets rid of code in which bugs have already been found in favour of the
same code everything else in the dumper uses to dump types.)
While we're doing that, change the recursive type dumper in question to
recursively dump info on arrays' element type, just as we do for all
types that reference other types. (Arrays are not a kind of reference
type in libctf, but perhaps we should change that in future and make
ctf_type_reference return the element type.)
ld/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* testsuite/ld-ctf/array.d: Adjust for dumper changes.
* testsuite/ld-ctf/data-func-conflicted.d: Likewise.
* testsuite/ld-ctf/diag-cttname-null.d: Likewise.
* testsuite/ld-ctf/diag-cuname.d: Likewise.
* testsuite/ld-ctf/diag-parlabel.d: Likewise.
* testsuite/ld-ctf/function.d: Likewise.
* testsuite/ld-ctf/slice.d: Likewise.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* ctf-dump.c (ctf_dump_objts): Dump by calling ctf_dump_format_type.
(ctf_dump_format_type): Don't emit the size for function objects.
Dump the element type of arrays like we dump the pointed-to type of
pointers, etc.
In most places in CTF dumper output, we emit 0x... for hex strings, but
in three places (top-level type IDs, string table offsets, and the file
magic number) we don't emit the 0x.
This is very confusing if by chance there are no hex digits in the
output. Add 0x consistently to everything, and adjust tests
accordingly. While we're at it, improve the indentation of the output
so that subsequent lines in aggregate output are indented by at least as
many columns as the colon in the type output. (Subsequent indentation
is still 4 spaces at a time.)
ld/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* testsuite/ld-ctf/array.d: Adjust for dumper changes.
* testsuite/ld-ctf/conflicting-cycle-1.B-1.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-1.B-2.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-1.parent.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-2.A-1.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-2.A-2.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-2.parent.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-3.C-1.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-3.C-2.d: Likewise.
* testsuite/ld-ctf/conflicting-cycle-3.parent.d: Likewise.
* testsuite/ld-ctf/conflicting-enums.d: Likewise.
* testsuite/ld-ctf/conflicting-typedefs.d: Likewise.
* testsuite/ld-ctf/cross-tu-cyclic-conflicting.d: Likewise.
* testsuite/ld-ctf/cross-tu-cyclic-nonconflicting.d: Likewise.
* testsuite/ld-ctf/cross-tu-into-cycle.d: Likewise.
* testsuite/ld-ctf/cross-tu-noncyclic.d: Likewise.
* testsuite/ld-ctf/cycle-1.d: Likewise.
* testsuite/ld-ctf/cycle-2.A.d: Likewise.
* testsuite/ld-ctf/cycle-2.B.d: Likewise.
* testsuite/ld-ctf/cycle-2.C.d: Likewise.
* testsuite/ld-ctf/data-func-conflicted.d: Likewise.
* testsuite/ld-ctf/diag-cttname-null.d: Likewise.
* testsuite/ld-ctf/diag-cuname.d: Likewise.
* testsuite/ld-ctf/diag-parlabel.d: Likewise.
* testsuite/ld-ctf/diag-wrong-magic-number-mixed.d: Likewise.
* testsuite/ld-ctf/function.d: Likewise.
* testsuite/ld-ctf/slice.d: Likewise.
* testsuite/ld-ctf/super-sub-cycles.d: Likewise.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* ctf-dump.c (ctf_dump_format_type): Add 0x to hex type IDs.
(ctf_dump_header): Add 0x to the hex magic number.
(ctf_dump_str): Add 0x to the hex string offsets.
(ctf_dump_membstate_t) <cdm_toplevel_indent>: New.
(ctf_dump_type): Adjust. Free it when we're done.
(type_hex_digits): New.
(ctf_dump_member): Align output depending on the width of the type
ID being generated. Use printf padding, not a loop, to generate
indentation.
The CTF declarator stack code (used by ctf_type_aname() and thus
ultimately by ctf-dump.c and objdump --ctf etc) contains careful
code to prepend array declarators to the stack it's building up
on the grounds that array declarators are ordered inside out: only
they're not, they're ordered outside in.
This has led to our (non-upstreamed) compiler emitting array declarators
backwards for years, because it looks backwards in the dumper unless
it's actually emitted backwards into the CTF so the dumper can wrongly
reverse it again: but
int[5][6]
should be an array of 6 int[5]s, not an array of 5 int[6]'s, so even if
the dumper gets it right, actual users calling ctf_array_info are going
to see a completely wrong type graph with the wrong bounds in it.
Fix trivial.
libctf/ChangeLog
2021-01-05 Nick Alcock <nick.alcock@oracle.com>
* ctf-decl.c (ctf_decl_push): Don't print array decls backwards.
