Go to file
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
bfd bfd, ld: add CTF section linking 2019-10-03 17:04:56 +01:00
binutils objdump: get CTF parent importing right 2019-10-03 17:04:56 +01:00
config
contrib
cpu
elfcpp
etc
gas
gdb gdb: Don't ignore all SIGSTOP when the signal handler is set to pass 2019-10-03 16:12:02 +01:00
gnulib
gold PR16794, gold ignores R_386_GOTOFF addend 2019-09-28 16:47:52 +09:30
gprof
include libctf: handle nonrepresentable types at link time 2019-10-03 17:04:56 +01:00
intl
ld libctf: installable libctf as a shared library 2019-10-03 17:04:56 +01:00
libctf libctf: handle nonrepresentable types at link time 2019-10-03 17:04:56 +01:00
libdecnumber
libiberty
opcodes
readline
sim
texinfo
zlib
.cvsignore
.gitattributes
.gitignore
ar-lib
ChangeLog libctf: installable libctf as a shared library 2019-10-03 17:04:56 +01:00
compile
config-ml.in
config.guess
config.rpath
config.sub
configure
configure.ac
COPYING
COPYING3
COPYING3.LIB
COPYING.LIB
COPYING.LIBGLOSS
COPYING.NEWLIB
depcomp
djunpack.bat
install-sh
libtool.m4
lt~obsolete.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
MAINTAINERS
Makefile.def libctf: installable libctf as a shared library 2019-10-03 17:04:56 +01:00
Makefile.in libctf: installable libctf as a shared library 2019-10-03 17:04:56 +01:00
Makefile.tpl
makefile.vms
missing
mkdep
mkinstalldirs
move-if-change
multilib.am
README
README-maintainer-mode
setup.com
src-release.sh
symlink-tree
test-driver
ylwrap

		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.