Nick Alcock 49da556c65 libctf, include: support an alternative encoding for nonrepresentable types ... Before now, types that could not be encoded in CTF were represented as references to type ID 0, which does not itself appear in the dictionary. This choice is annoying in several ways, principally that it forces generators and consumers of CTF to grow special cases for types that are referenced in valid dicts but don't appear. Allow an alternative representation (which will become the only representation in format v4) whereby nonrepresentable types are encoded as actual types with kind CTF_K_UNKNOWN (an already-existing kind theoretically but not in practice used for padding, with value 0). This is backward-compatible, because CTF_K_UNKNOWN was not used anywhere before now: it was used in old-format function symtypetabs, but these were never emitted by any compiler and the code to handle them in libctf likely never worked and was removed last year, in favour of new-format symtypetabs that contain only type IDs, not type kinds. In order to link this type, we need an API addition to let us add types of unknown kind to the dict: we let them optionally have names so that GCC can emit many different unknown types and those types with identical names will be deduplicated together. There are also small tweaks to the deduplicator to actually dedup such types, to let opening of dicts with unknown types with names work, to return the ECTF_NONREPRESENTABLE error on resolution of such types (like ID 0), and to print their names as something useful but not a valid C identifier, mostly for the sake of the dumper. Tests added in the next commit. include/ChangeLog 2021-05-06 Nick Alcock <nick.alcock@oracle.com> * ctf.h (CTF_K_UNKNOWN): Document that it can be used for nonrepresentable types, not just padding. * ctf-api.h (ctf_add_unknown): New. libctf/ChangeLog 2021-05-06 Nick Alcock <nick.alcock@oracle.com> * ctf-open.c (init_types): Unknown types may have names. * ctf-types.c (ctf_type_resolve): CTF_K_UNKNOWN is as non-representable as type ID 0. (ctf_type_aname): Print unknown types. * ctf-dedup.c (ctf_dedup_hash_type): Do not early-exit for CTF_K_UNKNOWN types: they have real hash values now. (ctf_dedup_rwalk_one_output_mapping): Treat CTF_K_UNKNOWN types like other types with no referents: call the callback and do not skip them. (ctf_dedup_emit_type): Emit via... * ctf-create.c (ctf_add_unknown): ... this new function. * libctf.ver (LIBCTF_1.2): Add it.		2021-05-06 09:30:59 +01:00
..
testsuite	libctf: fix memory leak in a test	2021-03-25 16:32:50 +00:00
.gitignore
aclocal.m4	Implement a workaround for GNU mak jobserver	2021-01-12 05:45:44 -08:00
ChangeLog	libctf, include: support an alternative encoding for nonrepresentable types	2021-05-06 09:30:59 +01:00
ChangeLog-2020
config.h.in
configure	libctf: fix ELF-in-BFD checks in the presence of ASAN	2021-03-25 16:32:51 +00:00
configure.ac	libctf: fix ELF-in-BFD checks in the presence of ASAN	2021-03-25 16:32:51 +00:00
ctf-archive.c	libctf: fix GNU style for do {} while	2021-03-18 12:37:55 +00:00
ctf-create.c	libctf, include: support an alternative encoding for nonrepresentable types	2021-05-06 09:30:59 +01:00
ctf-decl.c
ctf-decls.h
ctf-dedup.c	libctf, include: support an alternative encoding for nonrepresentable types	2021-05-06 09:30:59 +01:00
ctf-dump.c	libctf, dump: do not emit size or alignment if it would error	2021-03-25 16:32:46 +00:00
ctf-endian.h
ctf-error.c
ctf-hash.c	libctf: do not corrupt strings across ctf_serialize	2021-03-18 12:40:40 +00:00
ctf-impl.h	Provide an inline startswith function in bfd.h	2021-03-21 23:00:32 +10:30
ctf-inlines.h
ctf-intl.h
ctf-labels.c
ctf-link.c	libctf: fix some tabdamage and move some code around	2021-03-18 12:37:52 +00:00
ctf-lookup.c	libctf: don't dereference out-of-bounds locations in the qualifier hashtab	2021-03-25 16:32:49 +00:00
ctf-open-bfd.c	libctf: make ctf_bfdopen_ctfsect a debugger entry point	2021-03-25 16:32:49 +00:00
ctf-open.c	libctf, include: support an alternative encoding for nonrepresentable types	2021-05-06 09:30:59 +01:00
ctf-qsort_r.c
ctf-serialize.c	libctf, serialize: functions with no args have a NULL dtd_vlen	2021-03-25 16:32:48 +00:00
ctf-sha1.c
ctf-sha1.h
ctf-string.c	libctf: eliminate dtd_u, part 4: enums	2021-03-18 12:40:40 +00:00
ctf-subr.c
ctf-types.c	libctf, include: support an alternative encoding for nonrepresentable types	2021-05-06 09:30:59 +01:00
ctf-util.c
elf.h
libctf.ver	libctf, include: support an alternative encoding for nonrepresentable types	2021-05-06 09:30:59 +01:00
Makefile.am	libctf: split serialization and file writeout into its own file	2021-03-18 12:37:53 +00:00
Makefile.in	libctf: split serialization and file writeout into its own file	2021-03-18 12:37:53 +00:00
NEWS	libctf, include: support an alternative encoding for nonrepresentable types	2021-05-06 09:30:59 +01:00
swap.h	libctf: fix GNU style for do {} while	2021-03-18 12:37:55 +00:00