This patch started when I noticed that the unordered_set include
wasn't needed in abbrev-cache.h. (That was probably leftover from
some earlier implementation of the class.) Then, I noticed that the
class itself was under-commented. This patch fixes both issues.
PR cli/17151 points out that "set height 1" has pathological behavior
in gdb. What I see is that gdb will endlessly print the pagination
prompt. This patch takes a simple and expedient approach to a fix:
pretend that the height is really 2.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=17151
PR cli/20741 points out that when pagination is disabled, this also
disabled word wrapping. However, the manual documents that these
settings are separate -- if you intend to disable the wrapping, you
must use "set width unlimited".
This patch fixes the bug by letting the pagination-disabled case fall
through to the code that also handles word-wrapping.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=20741
This adds an implementation of the value_print method to Rust. As
described in PR rust/22254, this removes a bit of weird-looking output
from some "print"s -- because c_value_print is bypassed. I don't have
a test for the bug that inspired this patch, because I only know how
to reproduce it when using a relatively old Rust compiler. However,
the new "cast-printing" code in value_print is required, because
omitting this causes some existing tests to fail.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=22254
The current nightly Rust compiler (aka 1.61) added better DWARF
representation for unsized types. Fixing this is PR rust/21466; but
the code is actually the same as what is required to make slice
printing more useful, which is PR rust/23871. This patch implements
this. I tested this against various Rust compilers: 1.48, current
stable, current beta, and current nightly.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=21466
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=23871
This removes a bit of dead code from the Rust value printer. This
code wasn't always dead -- it fixed a real bug, and a test case was
added for it. However, once val_print was removed, it became
unnecessary.
The rust_compiler_version proc extracts the Rust compiler version from
the "rustc --version" output. For a beta compiler, the output looks
like:
rustc 1.60.0-beta.6 (7bccde197 2022-03-22)
This patch slightly relaxes the regexp -- removing a space -- so that
this can be understood by this proc.
With test-case gdb.ada/float-bits.exp and native we get:
...
(gdb) print 16llf#7FFFF7FF4054A56FA5B99019A5C8#^M
$9 = 5.0e+25^M
(gdb) PASS: gdb.ada/float-bits.exp: print 16llf#7FFFF7FF4054A56FA5B99019A5C8#
...
but with target board unix/-m32 we have instead:
...
(gdb) print 16llf#7FFFF7FF4054A56FA5B99019A5C8#^M
Cannot export value 2596145952482202326224873165792712 as 96-bits \
unsigned integer (must be between 0 and 79228162514264337593543950335)^M
(gdb) FAIL: gdb.ada/float-bits.exp: print 16llf#7FFFF7FF4054A56FA5B99019A5C8#
...
Fix this by testing whether 16llf is supported by doing ptype long_long_float
which gets us either:
...
type = <16-byte float>^M
...
or:
...
type = <12-byte float>^M
...
Tested on x86_64-linux with native and unix/-m32.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29041
Since score-tdep.c was removed, the WITH_SIM define is not used in
gdb. This patch removes it.
Note that re-running autoheader shows a separate change that was
missed. I've kept it in this patch to avoid extra work.
When running test-case gdb.go/methods.exp with make check we have:
...
(gdb) break main.T.Foo^M
Function "main.T.Foo" not defined.^M
Make breakpoint pending on future shared library load? (y or [n]) n^M
(gdb) XFAIL: gdb.go/methods.exp: gdb_breakpoint: set breakpoint at main.T.Foo
...
but with make check-readmore the XFAIL fails to trigger:
...
(gdb) break main.T.Foo^M
Function "main.T.Foo" not defined.^M
Make breakpoint pending on future shared library load? (y or [n]) n^M
(gdb) FAIL: gdb.go/methods.exp: gdb_breakpoint: set breakpoint at main.T.Foo
...
This happens because this gdb_test_multiple "maintenance print symbols"
regexp:
...
-re "\r\n$gdb_prompt $" {
...
matches the entire command output.
Fix this by adding the missing ^ at the regexp start.
Tested on x86_64-linux.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29064
Given:
- The prepare_to_access_memory machinery was added for non-stop mode.
- Only Linux supports non-stop.
- Linux no longer needs the prepare_to_access_memory machinery. In
fact, after the previous patch,
linux_process_target::prepare_to_access_memory became a nop.
Thus, prepare_to_access_memory can go away, simplifying core GDBserver
code.
Change-Id: I93ac8bfe66bd61c3d1c4a0e7d419335163120ecf
Similarly to how the native Linux target was changed
and subsequently reworked in these commits:
05c06f318fd9 Linux: Access memory even if threads are running
8a89ddbda2ec Avoid /proc/pid/mem races (PR 28065)
... teach GDBserver to access memory even when the current thread is
running, by always accessing memory via /proc/PID/mem.
The existing comment:
/* Neither ptrace nor /proc/PID/mem allow accessing memory through a
running LWP. */
... is incorrect for /proc/PID/mem does allow that.
Actually, from GDB's perspective, GDBserver could already access
memory while threads were running, but at the expense of pausing all
threads for the duration of the memory access, via
prepare_to_access_memory. This new implementation does not require
pausing any thread, thus
linux_process_target::prepare_to_access_memory /
linux_process_target::done_accessing_memory become nops. A subsequent
patch will remove the whole prepare_to_access_memory infrastructure
completely.
The GDBserver linux-low.cc implementation is simpler than GDB's
linux-nat.c's, because GDBserver always adds the unfollowed vfork/fork
children to the process list immediately when the fork/vfork event is
seen out of ptrace. I.e., there's no need to keep the file descriptor
stored on a side map, we can store it directly in the process
structure.
Change-Id: I0abfd782ceaa4ddce8d3e5f3e2dfc5928862ef61
The next patch in this series adds a common helper routine for both
memory reads and writes, like this:
static int
proc_xfer_memory (CORE_ADDR memaddr, unsigned char *readbuf,
const gdb_byte *writebuf, int len)
{
gdb_assert ((readbuf == nullptr) != (writebuf == nullptr));
...
}
int
linux_process_target::read_memory (CORE_ADDR memaddr,
unsigned char *myaddr, int len)
{
return proc_xfer_memory (memaddr, myaddr, nullptr, len);
}
linux_process_target::write_memory (CORE_ADDR memaddr,
const unsigned char *myaddr, int len)
{
return proc_xfer_memory (memaddr, nullptr, myaddr, len);
}
Surprisingly, the assertion fails. That happens because it can happen
that target_write_memory is called with LEN==0, due to this in
gdb/remote.c:
/* Determine whether the remote target supports binary downloading.
This is accomplished by sending a no-op memory write of zero length
to the target at the specified address. (...) */
void
remote_target::check_binary_download (CORE_ADDR addr)
{
...
p = rs->buf.data ();
*p++ = 'X';
p += hexnumstr (p, (ULONGEST) addr);
*p++ = ',';
p += hexnumstr (p, (ULONGEST) 0);
*p++ = ':';
*p = '\0';
In this scenario, in gdbserver's target_write_memory, the "myaddr"
argument of the_target->write_memory is passed the data() of a local
gdb::byte_vector (which is a specialized std::vector). It's valid for
std::vector::data() to return NULL when the vector is empty.
This commit adds an early return to target_write_memory to avoid
target backends having to care about this. For good measure, do the
same on the read side, in read_inferior_memory.
Change-Id: Iac8f04fcf99014c624ef4036bd318ca1771ad491
handle_qxfer_threads_proper needs to pause all threads even if the
target can read memory when threads are running, so use
target_pause_all instead, which is what the Linux implementation of
prepare_to_access_memory uses. (Only Linux implements this hook.)
A following patch will make the Linux backend be able to access memory
when threads are running, and thus will also make
prepare_to_access_memory do nothing, which would cause testsuite
regressions without this change.
Change-Id: I127fec7246b7c45b60dfa7341e781606bf54b5da
When running the internal AdaCore test suite against the new DWARF
indexer, I found one regression on RISC-V. The test in question uses
--gc-sections, and winds up with an entry in the middle of a
.debug_aranges that has both address and length of 0. In this
scenario, gdb assumes the entries are terminated and then proceeds to
reject the section because it reads a subsequent entry as if it were a
header.
It seems to me that, because each header describes the size of each
.debug_aranges CU, it's better to simply ignore 0,0 entries and simply
read to the end. That is what this patch does.
I've patched an existing test to provide a regression test for this.
Windows 10 introduced SetThreadDescription and GetThreadDescription, a
simpler way to set a thread's name. This changes gdb and gdbserver to
use this convention when it is available.
This is part of PR win32/29050.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29050
This patch is a bit different from the rest of the series, in that it
is a change to gdb's behavior on the host. It changes gdb's thread
pool to try to set the thread name on Windows, if SetThreadDescription
is available.
This is part of PR win32/29050.
This patch isn't likely to be useful to many people in the short term,
because the Windows port of the libstdc++ thread code is not upstream.
(AdaCore uses it, and sent it upstream, but it did not land, I don't
know why.) However, if that patch does ever go in, or presumably if
you build using some other C++ runtime library, then this will be
useful.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29050
Currently, gdb's native Windows target implements the exception-based
approach for setting thread names, but gdbserver does not. This patch
moves handle_ms_vc_exception to the shared nat/windows-nat.c code, as
preparation for adding this support to gdbserver.
target_read_string takes a byte order parameter, but only uses this to
check whether a given character is zero. This is readily done without
requiring the parameter, so remove it.
I noticed that nat/windows-nat.c checks __USEWIDE, but nothing sets it
there -- I forgot to copy over the definition when making this file.
This patch tries to fix the problem. I don't have a Cygwin setup, so
I don't know whether this is sufficient, but it's probably necessary.
Pedro Alves warned me that there is a race in
gdb.dwarf2/calling-convention.exp making the test sometimes fail on his
setup. This can be reliably reproduced using :
make check-read1 TESTS="gdb.dwarf2/calling-convention.exp"
The relevant part of the gdb.log file is:
return 35
Function 'foo' does not follow the target calling convention.
If you continue, setting the return value will probably lead to unpredictable behaviors.
Make foo return now? (y or n) PASS: gdb.dwarf2/calling-convention.exp: return 35
n
Not confirmed
(gdb) FAIL: gdb.dwarf2/calling-convention.exp: finish
The issue is that when doing the test for "return 35", the DejaGnu test
sends "n" (to tell GDB not to perform the return action) but never
consumes the "Not confirmed" acknowledgment sent by GDB. Later, when
trying to do the next test, DejaGnu tries to match the leftover output
from the "return" test. As this output is not expected, the test fails.
Fix by using gdb_test to send the "n" answer and match the confirmation
and consume all output to the prompt.
Also do minor adjustments to the main regex:
- Remove the leading ".*" which is not required.
- Ensure that the "?" from the question is properly escaped.
Tested on x86_64-gnu-linux, using
- make check TESTS="gdb.dwarf2/calling-convention.exp"
- make check-read1 TESTS="gdb.dwarf2/calling-convention.exp"
- make check-readmore TESTS="gdb.dwarf2/calling-convention.exp"
Co-authored-by: Pedro Alves <pedro@palves.net>
Change-Id: I42858b13db2cbd623c5c1739de65ad423e0c0938
Currently, one use of target_waitstatus yields a warning:
target/waitstatus.h: In function 'void stop_all_threads()':
target/waitstatus.h:175:13: warning: 'ws.target_waitstatus::m_value' may be used uninitialized in this function [-Wmaybe-uninitialized]
175 | m_value = other.m_value;
| ~~~~~~~~^~~~~~~~~~~~~~~
This patch silences the warning. I tried the "volatile member"
approach that was used for gdb::optional, but that didn't work, so
this patch simply initializes the member.
Internally at AdaCore, we recently started testing a 64-bit gdb
debugging 32-bit processes. This failed with gdb head, but not with
gdb 11.
The tests fail like this:
Starting program: [...].exe
warning: Could not load shared library symbols for WOW64_IMAGE_SECTION.
Do you need "set solib-search-path" or "set sysroot"?
warning: Could not load shared library symbols for WOW64_IMAGE_SECTION.
Do you need "set solib-search-path" or "set sysroot"?
warning: Could not load shared library symbols for NOT_AN_IMAGE.
Do you need "set solib-search-path" or "set sysroot"?
warning: Could not load shared library symbols for NOT_AN_IMAGE.
Do you need "set solib-search-path" or "set sysroot"?
After some debugging and bisecting, to my surprise the bug was
introduced by commit 183be222 ("gdb, gdbserver: make target_waitstatus
safe").
The problem occurs in handle_exception. Previously the code did:
- ourstatus->kind = TARGET_WAITKIND_STOPPED;
[...]
case EXCEPTION_BREAKPOINT:
[...]
- ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
[...]
/* FALLTHROUGH */
case STATUS_WX86_BREAKPOINT:
DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_BREAKPOINT");
- ourstatus->value.sig = GDB_SIGNAL_TRAP;
[...]
- last_sig = ourstatus->value.sig;
However, in the new code, the fallthrough case does:
+ ourstatus->set_stopped (GDB_SIGNAL_TRAP);
... which changes the 'kind' in 'ourstatus' after falling through.
This patch rearranges the 'last_sig' setting to more closely match
what was done before (this is probably not strictly needed but also
seemed harmless), and removes the fall-through in the
'ignore_first_breakpoint' case when __x86_64__ is defined.
This slightly reorganizes the Python events documentation. It hoists
the "ThreadEvent" text out of the list of events, where it seemed to
be misplaced. It tidies the formatting a little bit (adding some
vertical space for easier reading in info), fixes a typo, adds some
missing commas, and fixes an incorrect reference to NewInferiorEvent.
Building with clang++-14, I see:
CXX dwarf2/cooked-index.o
In file included from /home/smarchi/src/binutils-gdb/gdb/dwarf2/cooked-index.c:21:
/home/smarchi/src/binutils-gdb/gdb/dwarf2/cooked-index.h:172:12: error: explicitly defaulted move constructor is implicitly deleted [-Werror,-Wdefaulted-function-deleted]
explicit cooked_index (cooked_index &&other) = default;
^
/home/smarchi/src/binutils-gdb/gdb/dwarf2/cooked-index.h:225:16: note: move constructor of 'cooked_index' is implicitly deleted because field 'm_storage' has a deleted move constructor
auto_obstack m_storage;
^
/home/smarchi/src/binutils-gdb/gdb/../gdbsupport/gdb_obstack.h:128:28: note: 'auto_obstack' has been explicitly marked deleted here
DISABLE_COPY_AND_ASSIGN (auto_obstack);
^
In file included from /home/smarchi/src/binutils-gdb/gdb/dwarf2/cooked-index.c:21:
/home/smarchi/src/binutils-gdb/gdb/dwarf2/cooked-index.h:174:17: error: explicitly defaulted move assignment operator is implicitly deleted [-Werror,-Wdefaulted-function-deleted]
cooked_index &operator= (cooked_index &&other) = default;
^
/home/smarchi/src/binutils-gdb/gdb/dwarf2/cooked-index.h:225:16: note: move assignment operator of 'cooked_index' is implicitly deleted because field 'm_storage' has a deleted move assignment operator
auto_obstack m_storage;
^
/home/smarchi/src/binutils-gdb/gdb/../gdbsupport/gdb_obstack.h:128:3: note: 'operator=' has been explicitly marked deleted here
DISABLE_COPY_AND_ASSIGN (auto_obstack);
^
/home/smarchi/src/binutils-gdb/gdb/../include/ansidecl.h:425:8: note: expanded from macro 'DISABLE_COPY_AND_ASSIGN'
void operator= (const TYPE &) = delete
^
We explicitly make cooked_index have a default move constructor and
move assignment operator. But it doesn't actually happen because
cooked_index has a field of type auto_obstack, which isn't movable.
We don't actually need cooked_index to be movable at the moment, so
remove those lines.
Change-Id: Ifc1fe3d7d67e3ae1a14363d6c1869936fe80b0a2
Currently, the configure check for std::thread relies on pthreads
existing. However, this means that if std::thread is implemented for
a non-pthreads host, then the check will yield the wrong answer. This
happened in AdaCore internal builds. Here, we have this GCC patch:
https://gcc.gnu.org/legacy-ml/gcc-patches/2019-06/msg01840.html
... which adds mingw support to GCC's gthreads implementation, and
also to std::thread.
This configure change fixes this problem and enables threading for
gdb.
When I build gdb with gcc 8.3, there exist the following build errors,
rename the typedef to task_t to fix them.
CXX thread-pool.o
In file included from /home/loongson/gdb.git/gdbsupport/thread-pool.cc:21:
/home/loongson/gdb.git/gdbsupport/../gdbsupport/thread-pool.h: In member function ‘std::future<void> gdb::thread_pool::post_task(std::function<void()>&&)’:
/home/loongson/gdb.git/gdbsupport/../gdbsupport/thread-pool.h:69:44: error: declaration of ‘task’ shadows a previous local [-Werror=shadow=local]
std::packaged_task<void ()> task (std::move (func));
^~~~
/home/loongson/gdb.git/gdbsupport/../gdbsupport/thread-pool.h:102:39: note: shadowed declaration is here
typedef std::packaged_task<void ()> task;
^~~~
/home/loongson/gdb.git/gdbsupport/../gdbsupport/thread-pool.h: In member function ‘std::future<_Res> gdb::thread_pool::post_task(std::function<T()>&&)’:
/home/loongson/gdb.git/gdbsupport/../gdbsupport/thread-pool.h:80:41: error: declaration of ‘task’ shadows a previous local [-Werror=shadow=local]
std::packaged_task<T ()> task (std::move (func));
^~~~
/home/loongson/gdb.git/gdbsupport/../gdbsupport/thread-pool.h:102:39: note: shadowed declaration is here
typedef std::packaged_task<void ()> task;
^~~~
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
On openSUSE Leap 15.3, mpx support has been disabled for m32, so I run into:
...
(gdb) run ^M
Starting program: outputs/gdb.arch/i386-mpx/i386-mpx ^M
[Thread debugging using libthread_db enabled]^M
Using host libthread_db library "/lib64/libthread_db.so.1".^M
No MPX support^M
...
and eventually into all sort of fails in this and other mpx test-cases.
Fix this by detecting the "No MPX support" message in have_mpx.
Tested on x86_64-linux with target boards unix and unix/-m32.
Before the change tc-m68k maintained a list of seen labels.
Alignment check traversed label list to resolve symbol to label.
This caused quadratic slowdown as each symbol was checked against
each label. Worst affected files are the ones built with debugging
enabled as DWARF generates many labels.
The change embeds auxiliary label information right into symbol using
TC_SYMFIELD_TYPE.
Before the change test from PR 29058 did not finish in 10 minutes. After
the change it finishes in 2 seconds.
gas/ChangeLog:
PR 29058
* config/tc-m68k.h (TC_SYMFIELD_TYPE): define as m68k_tc_sy.
* config/tc-m68k.c (m68k_frob_label): Use TC_SYMFIELD_TYPE to
store label information.
Fix this error when building with clang++-14:
CXX complaints.o
/home/smarchi/src/binutils-gdb/gdb/complaints.c:130:65: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
g_complaint_interceptor->m_complaints.insert (string_vprintf (fmt, args));
^~~
Change-Id: I0ef11f970510eb8638d1651fa0d5eeecd6a9d31a
Building with clang++-14, I see:
CXX mips-tdep.o
/home/smarchi/src/binutils-gdb/gdb/mips-tdep.c:453:12: error: use of bitwise '|' with boolean operands [-Werror,-Wbitwise-instead-of-logical]
return !(MSYMBOL_TARGET_FLAG_MIPS16 (msym)
~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/smarchi/src/binutils-gdb/gdb/mips-tdep.h:54:2: note: expanded from macro 'MSYMBOL_TARGET_FLAG_MIPS16'
(sym)->target_flag_1 ()
^
/home/smarchi/src/binutils-gdb/gdb/mips-tdep.c:453:12: note: cast one or both operands to int to silence this warning
/home/smarchi/src/binutils-gdb/gdb/mips-tdep.h:54:2: note: expanded from macro 'MSYMBOL_TARGET_FLAG_MIPS16'
(sym)->target_flag_1 ()
^
That's since commit e165fcef1e7 ("gdb: remove MSYMBOL_TARGET_FLAG_{1,2}
macros"). Fix this by using the boolean || rather than the bitwise |,
since the new methods return bool values. No change in behavior
expected.
Change-Id: Ia82664135aa25db64c29c92f5c1141859d345bf7
Tromey noticed that intrusive_list_node leaves its data members
public, which seems sub-optimal.
This commit makes intrusive_list_node's data fields private.
intrusive_list_iterator, intrusive_list_reverse_iterator, and
intrusive_list do need to access the fields, so they are made friends.
Change-Id: Ia8b306b40344cc218d423c8dfb8355207a612ac5
Now that Ada is able to parse & print 0xffffffffffffffff (2^64-1) in
hex, move it to the else branch like most other languages.
Change-Id: Ib305f6bb2b6b230a1190ea783b245b865821094c
On irc, Pedro pointed out that Ada couldn't properly handle
0xffffffffffffffff. This used to work, but is a regression due to
some patches I wrote in the Ada lexer. This patch fixes the bug.
Reading a simple file compiled with :
$ gcc -DONE=1 -gdwarf-4 -g3 test.c
$ gcc --version
gcc (Ubuntu 9.4.0-1ubuntu1~20.04) 9.4.0
I get:
Reading symbols from /tmp/cwd/a.out...
/home/smarchi/src/binutils-gdb/gdb/dwarf2/cooked-index.c:332:11: runtime error: null pointer passed as argument 2, which is declared to never be null
It looks like even if the size is 0 (the size of the `entries` vector is
0), we shouldn't be passing a NULL pointer to memcpy. And
`entries.data ()` returns NULL.
Fix that by using std::vector::insert to insert the items of entries
into m_entries. I haven't checked, but it should essentially compile
down to a memcpy, since the vector elements are trivially copyiable.
Change-Id: I75f1c901e9b522e42e89eb5936e2c70d68eb21e5
Change this field to an std::vector to facilitate memory management.
Since the linetable_entry array is copied into the symtab resulting from
the subfile, it is possible to change it without changing how symtab
stores the linetable entries (which would be a much larger change).
There is a small change in buildsym_compunit::record_line to avoid
accessing a now invalid linetable_entry. Before this patch, we keep a
pointer to the last linetable entry, pop it from the vector, and then
read last->line. It works with the manually-maintained array, but since
we now use std::vector::pop_back, I am afraid that it could be flagged
as an invalid access by the various static / dynamic analysis tools to
access the linetable_entry object after popping it from the vector.
Instead, record just the line number in an optional and use it.
There are substantial changes in xcoffread.c that simplify the code, but
I can't test them. I was hesitant to do this change because of that,
but I decided to send it anyway. I don't think that an almost dead
platform should hold back improving the code in the common parts of GDB.
The changes in xcoffread.c are:
- Make arrange_linetable "arrange" the linetable passed as a parameter,
instead of returning possibly a new one, possibly the same one.
- In the "Process main file's line numbers.", I'm not too sure what
happens. We get the lintable from "main_subfile", "arrange" it, but
then assign the result to the current subfile, obtained with
get_current_subfile. I assume that the current subfile is also the
main one, so now I just call arrange_linetable on the main subfile's
line table.
- Remove that weird "Useless if!!!" FIXME comment. It's been there
forever, but the "if" is still there, so I guess the "if" can stay
there.
Change-Id: I11799006fd85189e8cf5bd3a168f8f38c2c27a80
Reduce manual memory management and make the code a bit easier to read.
This helps me a bit in the following patch.
I don't have a way to test this, it's best-effort.
Change-Id: I64af9cd756311deabc6cd95e701dfb21234a40a5
Change subfile::name to be a string, for easier memory management.
Change buildsym_compunit::m_comp_dir as well, since we move one in to
the other at some point in patch_subfile_names, so it's easier to do
both at the same time. There are various NULL checks for both fields
currently, replace them with empty checks, I think it ends up
equivalent.
I can't test the change in xcoffread.c, it's best-effort.
Change-Id: I62b5fb08b2089e096768a090627ac7617e90a016
