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 afd78bd6f0 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.
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.
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 676c3ecbad, 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.
ctf_serialize and its various pieces may be split out into a separate
file now, but ctf_serialize is still far too long and disordered, mixing
header initialization, sizing of multiple CTF sections, sorting and
emission of multiple CTF sections, strtab construction and ctf_dict_t
copying into a single ugly organically-grown mess.
Fix the worst of this by migrating all section sizing and emission into
separate functions, two per section (or class of section in the case of
the symtypetabs). Only the variable section is now sized and emitted
directly in ctf_serialize (because it only takes about three lines to do
so).
The section sizes themselves are still maintained by ctf_serialize so
that it can work out the header offsets, but ctf_symtypetab_sect_sizes
and ctf_emit_symtypetab_sects share a lot of extra state: migrate that
into a shared structure, emit_symtypetab_state_t.
(Test results unchanged.)
libctf/ChangeLog
2021-03-18 Nick Alcock <nick.alcock@oracle.com>
* ctf-serialize.c: General reshuffling, and...
(emit_symtypetab_state_t): New, migrated from
local variables in ctf_serialize.
(ctf_serialize): Split out most section sizing and
emission.
(ctf_symtypetab_sect_sizes): New (split out).
(ctf_emit_symtypetab_sects): Likewise.
(ctf_type_sect_size): Likewise.
(ctf_emit_type_sect): Likewise.
The code to serialize CTF dicts just gets bigger and bigger as the
dictionary's complexity grows: adding symtypetabs almost doubled it on
its own. It's long past time to split this out into its own source
file, accompanied by the functions that do the actual writeout.
This leaves ctf-create.c populated exclusively by functions related to
actual writable dict creation (ctf_add_*, ctf_create etc), and leaves
both files a much more reasonable size.
libctf/ChangeLog
2021-03-18 Nick Alcock <nick.alcock@oracle.com>
* ctf-create.c (symtypetab_delete_nonstatic_vars): Move
into ctf-serialize.c.
(ctf_symtab_skippable): Likewise.
(CTF_SYMTYPETAB_EMIT_FUNCTION): Likewise.
(CTF_SYMTYPETAB_EMIT_PAD): Likewise.
(CTF_SYMTYPETAB_FORCE_INDEXED): Likewise.
(symtypetab_density): Likewise.
(emit_symtypetab): Likewise.
(emit_symtypetab_index): Likewise.
(ctf_copy_smembers): Likewise.
(ctf_copy_lmembers): Likewise.
(ctf_copy_emembers): Likewise.
(ctf_sort_var): Likewise.
(ctf_serialize): Likewise.
(ctf_gzwrite): Likewise.
(ctf_compress_write): Likewise.
(ctf_write_mem): Likewise.
(ctf_write): Likewise.
* ctf-serialize.c: New file.
* Makefile.am (libctf_nobfd_la_SOURCES): Add it.
* Makefile.in: Regenerate.
