Commit Graph

5 Commits

Author SHA1 Message Date
Nick Alcock
791915db42 libctf: handle nonrepresentable types at link time
GCC can emit references to type 0 to indicate that this type is one that
is not representable in the version of CTF it emits (for instance,
version 3 cannot encode vector types).  Type 0 is already used in the
function section to indicate padding inserted to skip functions we do
not want to encode the type of, so using zero in this way is a good
extension of the format: but libctf reports such types as ECTF_BADID,
which is indistinguishable from file corruption via links to truly
nonexistent types with IDs like 0xDEADBEEF etc, which we really do want
to stop for.

In particular, this stops all traversals of types dead at this point,
preventing us from even dumping CTF files containing unrepresentable
types to see what's going on!

So add a new error, ECTF_NONREPRESENTABLE, which is returned by
recursive type resolution when a reference to a zero type is found.  (No
zero type is ever emitted into the CTF file by GCC, only references to
one).  We can't do much with types that are ultimately nonrepresentable,
but we can do enough to keep functioning.

Adjust ctf_add_type to ensure that top-level types of type zero and
structure and union members of ultimate type zero are simply skipped
without reporting an error, so we can copy structures and unions that
contain nonrepresentable members (skipping them and leaving a hole where
they would be, so no consumers downstream of the linker need to worry
about this): adjust the dumper so that we dump members of
nonrepresentable types in a simple form that indicates
nonrepresentability rather than terminating the dump, and do not falsely
assume all errors to be -ENOMEM: adjust the linker so that types that
fail to get added are simply skipped, so that both nonrepresentable
types and outright errors do not terminate the type addition, which
could skip many valid types and cause further errors when variables of
those types are added.

In future, when we gain the ability to call back to the linker to report
link-time type resolution errors, we should report failures to add all
but nonrepresentable types.  But we can't do that yet.

v5: Fix tabdamage.

include/
	* ctf-api.h (ECTF_NONREPRESENTABLE): New.
libctf/
	* ctf-types.c (ctf_type_resolve): Return ECTF_NONREPRESENTABLE on
	type zero.
	* ctf-create.c (ctf_add_type): Detect and skip nonrepresentable
	members and types.
	(ctf_add_variable): Likewise for variables pointing to them.
	* ctf-link.c (ctf_link_one_type): Do not warn for nonrepresentable
	type link failure, but do warn for others.
	* ctf-dump.c (ctf_dump_format_type): Likewise.  Do not assume all
	errors to be ENOMEM.
	(ctf_dump_member): Likewise.
	(ctf_dump_type): Likewise.
	(ctf_dump_header_strfield): Do not assume all errors to be ENOMEM.
	(ctf_dump_header_sectfield): Do not assume all errors to be ENOMEM.
	(ctf_dump_header): Likewise.
	(ctf_dump_label): likewise.
	(ctf_dump_objts): likewise.
	(ctf_dump_funcs): likewise.
	(ctf_dump_var): likewise.
	(ctf_dump_str): Likewise.
2019-10-03 17:04:56 +01:00
Nick Alcock
0ac6231298 libctf: Add iteration over non-root types
The existing function ctf_type_iter lets you iterate over root-visible
types (types you can look up by name).  There is no way to iterate over
non-root-visible types, which is troublesome because both the linker
and dumper want to do that.

So add a new function that can do it: the callback it takes accepts
an extra parameter which indicates whether the type is root-visible
or not.

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

libctf/
	* ctf_types.c (ctf_type_iter_all): New.
2019-10-03 17:04:55 +01:00
Nick Alcock
12a0b67d28 libctf: introduce ctf_func_type_{info,args}, ctf_type_aname_raw
The first two of these allow you to get function type info and args out
of the types section give a type ID: astonishingly, this was missing
from libctf before now: so even though types of kind CTF_K_FUNCTION were
supported, you couldn't find out anything about them.  (The existing
ctf_func_info and ctf_func_args only allow you to get info about
functions in the function section, i.e. given symbol table indexes, not
type IDs.)

The second of these allows you to get the raw undecorated name out of
the CTF section (strdupped for safety) without traversing subtypes to
build a full C identifier out of it.  It's useful for things that are
already tracking the type kind etc and just need an unadorned name.

include/
	* ctf-api.h (ECTF_NOTFUNC): Fix description.
	(ctf_func_type_info): New.
	(ctf_func_type_args): Likewise.
libctf/
	* ctf-types.c (ctf_type_aname_raw): New.
	(ctf_func_type_info): Likewise.
	(ctf_func_type_args): Likewise.
	* ctf-error.c (_ctf_errlist): Fix description.
2019-07-18 20:53:57 +01:00
Jose E. Marchesi
a0486bac41 libctf: fix a number of build problems found on Solaris and NetBSD
- Use of nonportable <endian.h>
- Use of qsort_r
- Use of zlib without appropriate magic to pull in the binutils zlib
- Use of off64_t without checking (fixed by dropping the unused fields
  that need off64_t entirely)
- signedness problems due to long being too short a type on 32-bit
  platforms: ctf_id_t is now 'unsigned long', and CTF_ERR must be
  used only for functions that return ctf_id_t
- One lingering use of bzero() and of <sys/errno.h>

All fixed, using code from gnulib where possible.

Relatedly, set cts_size in a couple of places it was missed
(string table and symbol table loading upon ctf_bfdopen()).

binutils/
	* objdump.c (make_ctfsect): Drop cts_type, cts_flags, and
	cts_offset.
	* readelf.c (shdr_to_ctf_sect): Likewise.
include/
	* ctf-api.h (ctf_sect_t): Drop cts_type, cts_flags, and cts_offset.
	(ctf_id_t): This is now an unsigned type.
	(CTF_ERR): Cast it to ctf_id_t.  Note that it should only be used
	for ctf_id_t-returning functions.
libctf/
	* Makefile.am (ZLIB): New.
	(ZLIBINC): Likewise.
	(AM_CFLAGS): Use them.
	(libctf_a_LIBADD): New, for LIBOBJS.
	* configure.ac: Check for zlib, endian.h, and qsort_r.
	* ctf-endian.h: New, providing htole64 and le64toh.
	* swap.h: Code style fixes.
	(bswap_identity_64): New.
	* qsort_r.c: New, from gnulib (with one added #include).
	* ctf-decls.h: New, providing a conditional qsort_r declaration,
	and unconditional definitions of MIN and MAX.
	* ctf-impl.h: Use it.  Do not use <sys/errno.h>.
	(ctf_set_errno): Now returns unsigned long.
	* ctf-util.c (ctf_set_errno): Adjust here too.
	* ctf-archive.c: Use ctf-endian.h.
	(ctf_arc_open_by_offset): Use memset, not bzero.  Drop cts_type,
	cts_flags and cts_offset.
	(ctf_arc_write): Drop debugging dependent on the size of off_t.
	* ctf-create.c: Provide a definition of roundup if not defined.
	(ctf_create): Drop cts_type, cts_flags and cts_offset.
	(ctf_add_reftype): Do not check if type IDs are below zero.
	(ctf_add_slice): Likewise.
	(ctf_add_typedef): Likewise.
	(ctf_add_member_offset): Cast error-returning ssize_t's to size_t
	when known error-free.  Drop CTF_ERR usage for functions returning
	int.
	(ctf_add_member_encoded): Drop CTF_ERR usage for functions returning
	int.
	(ctf_add_variable): Likewise.
	(enumcmp): Likewise.
	(enumadd): Likewise.
	(membcmp): Likewise.
	(ctf_add_type): Likewise.  Cast error-returning ssize_t's to size_t
	when known error-free.
	* ctf-dump.c (ctf_is_slice): Drop CTF_ERR usage for functions
	returning int: use CTF_ERR for functions returning ctf_type_id.
	(ctf_dump_label): Likewise.
	(ctf_dump_objts): Likewise.
	* ctf-labels.c (ctf_label_topmost): Likewise.
	(ctf_label_iter): Likewise.
	(ctf_label_info): Likewise.
	* ctf-lookup.c (ctf_func_args): Likewise.
	* ctf-open.c (upgrade_types): Cast to size_t where appropriate.
	(ctf_bufopen): Likewise.  Use zlib types as needed.
	* ctf-types.c (ctf_member_iter): Drop CTF_ERR usage for functions
	returning int.
	(ctf_enum_iter): Likewise.
	(ctf_type_size): Likewise.
	(ctf_type_align): Likewise.  Cast to size_t where appropriate.
	(ctf_type_kind_unsliced): Likewise.
	(ctf_type_kind): Likewise.
	(ctf_type_encoding): Likewise.
	(ctf_member_info): Likewise.
	(ctf_array_info): Likewise.
	(ctf_enum_value): Likewise.
	(ctf_type_rvisit): Likewise.
	* ctf-open-bfd.c (ctf_bfdopen): Drop cts_type, cts_flags and
	cts_offset.
	(ctf_simple_open): Likewise.
	(ctf_bfdopen_ctfsect): Likewise.  Set cts_size properly.
	* Makefile.in: Regenerate.
	* aclocal.m4: Likewise.
	* config.h: Likewise.
	* configure: Likewise.
2019-05-31 11:10:51 +02:00
Nick Alcock
316afdb130 libctf: core type lookup
Finally we get to the functions used to actually look up and enumerate
properties of types in a container (names, sizes, members, what type a
pointer or cv-qual references, determination of whether two types are
assignment-compatible, etc).

With a very few exceptions these do not work for types newly added via
ctf_add_*(): they only work on types in read-only containers, or types
added before the most recent call to ctf_update().

This also adds support for lookup of "variables" (string -> type ID
mappings) and for generation of C type names corresponding to a type ID.

libctf/
	* ctf-decl.c: New file.
	* ctf-types.c: Likewise.
	* ctf-impl.h: New declarations.

include/
	* ctf-api.h (ctf_visit_f): New definition.
	(ctf_member_f): Likewise.
	(ctf_enum_f): Likewise.
	(ctf_variable_f): Likewise.
	(ctf_type_f): Likewise.
	(ctf_type_isparent): Likewise.
	(ctf_type_ischild): Likewise.
	(ctf_type_resolve): Likewise.
	(ctf_type_aname): Likewise.
	(ctf_type_lname): Likewise.
	(ctf_type_name): Likewise.
	(ctf_type_sizee): Likewise.
	(ctf_type_align): Likewise.
	(ctf_type_kind): Likewise.
	(ctf_type_reference): Likewise.
	(ctf_type_pointer): Likewise.
	(ctf_type_encoding): Likewise.
	(ctf_type_visit): Likewise.
	(ctf_type_cmp): Likewise.
	(ctf_type_compat): Likewise.
	(ctf_member_info): Likewise.
	(ctf_array_info): Likewise.
	(ctf_enum_name): Likewise.
	(ctf_enum_value): Likewise.
	(ctf_member_iter): Likewise.
	(ctf_enum_iter): Likewise.
	(ctf_type_iter): Likewise.
	(ctf_variable_iter): Likewise.
2019-05-28 17:08:14 +01:00