Set print symbol off in mi-var-display.exp

Hi,
I see the following fail on arm-none-eabi target,

-var-evaluate-expression -f nat foo^M
^done,value="0x3 <_ftext+2>"^M
(gdb) ^M
FAIL: gdb.mi/mi-var-display.exp: eval variable -f nat foo

the "<_ftext+2>" isn't expected in the test, so "set print symbol off"
can prevent printing it.  It is obvious and I'll commit it in three
days if no comments.

gdb/testsuite:

2014-09-09  Yao Qi  <yao@codesourcery.com>

	* gdb.mi/mi-var-display.exp: Set print symbol off.
Replace use of magic number with named constant.

gdb/ChangeLog:

	* guile/scm-cmd.c (gdbscm_parse_command_name): Replace magic number
	with named constant.  Fix style of pointer comparison.
	* python/py-cmd.c (gdbpy_parse_command_name): Ditto.
gdb.guile/scm-error.exp: Handle guile 2.2 backtrace output.

gdb/testsuite/ChangeLog:

	* gdb.guile/scm-error.exp: Handle guile 2.2 backtrace output.
Fix for PR 17247: Block SIGCHLD while initializing Guile.

The problem here is that if a thread other than gdb's main thread
gets a SIGCHLD (it's an asynchronous signal so the kernel will
essentially pick a random thread) then gdb will hang if it is
in sigsuspend when the SIGCHLD is delivered.  The other thread
will see the signal and the sigsuspend won't "wake up".

Guile and libgc should be blocking SIGCHLD in their threads,
but we need to work with Guile 2.0 and libgc 7.4.
The problem first shows up in libgc 7.4 because it is the first
release that enables multiple marker threads by default.

gdb/ChangeLog:

	PR 17247
	* guile.c: #include <signal.h>.
	(_initialize_guile): Block SIGCHLD while initializing Guile.

	Replaces the following, which is reverted.

	2014-07-26  Doug Evans  <xdje42@gmail.com>

	PR 17185
	* configure.ac: Add check for header gc/gc.h.
	Add check for function setenv.
	* configure: Regenerate.
	* config.in: Regenerate.
	* guile/guile.c (_initialize_guile): Add workaround for libgc 7.4.0.
Fix regression in default.exp caused by _caller_is, etc.

gdb/testsuite/ChangeLog:

	* gdb.base/default.exp (show_conv_list): Add _caller_is,
	_caller_matches, _any_caller_is, _any_caller_matches.
[PATCH][ARM] Add Cortex-A17 support to gas

     * config/tc-arm.c (arm_cpus): Add cortex-a17.
Fix missing "struct iovec" definition on some x86-linux.

The following patch...

    commit 3116063bd617de56fbc3bad046a692b1fb363a9d
    Date:   Fri Jun 27 09:52:29 2014 +0100
    Subject: Tidy #include lists

... introduced a build failure on certain x86 GNU/Linux distributions
(reproduced on SuSE 10 and RHES4) due to "struct iovec" not being
defined. This struct is defined in <sys/uio.h>, which used to be
explicitly included, but no longer is after the commit above was
applied.

    [...]/i386-linux-nat.c: In function 'fetch_xstateregs':
    [...]/i386-linux-nat.c:325:16: error: storage size of 'iov' isn't known
    [...]/i386-linux-nat.c: In function 'store_xstateregs':
    [...]/i386-linux-nat.c:348:16: error: storage size of 'iov' isn't known
    make[2]: *** [i386-linux-nat.o] Error 1

It seems to be working on newer GNU/Linux distros thanks to indirect
inclusion of <sys/uio.h>, but it does not work on some other versions
of the same distros. This is why indirect includes of public APIs
should be avoided if at all possible.

This patch fixes the issue by adding the explicit include back.

gdb/ChangeLog:

        * i386-linux-nat.c, x86-linux-nat.c: Add <sys/uio.h> #include.
GDB/testsuite: Extend the time gdbserver is waited for

Gdbserver support code uses the global timeout value to determine when
to stop waiting for a gdbserver process being started to respond before
continuing anyway.  This timeout is usually as low as 10s and may not
be enough in this context, for example on the first run where the
filesystem cache is cold, even if it is elsewhere.

E.g. I observe this reliably with gdbserver started the first time in
QEMU running in the system emulation mode:

(gdb) file .../gdb.base/advance
Reading symbols from .../gdb.base/advance...done.
(gdb) delete breakpoints
(gdb) info breakpoints
No breakpoints or watchpoints.
(gdb) break main
Breakpoint 1 at 0x87f8: file .../gdb.base/advance.c,
line 41.
(gdb) set remotetimeout 15
(gdb) kill
The program is not being run.
(gdb)
[...]
.../bin/gdbserver --once :6014 advance
target remote localhost:6014
Remote debugging using localhost:6014
Remote communication error.  Target disconnected.: Connection reset by peer.
(gdb) continue
The program is not being run.
(gdb) Process advance created; pid = 999
Listening on port 6014
FAIL: gdb.base/advance.exp: Can't run to main

-- notice how the test harness proceeded with the `target remote ...'
command even though gdbserver hasn't completed its startup yet.  A
while later when it's finally ready it's too late already.  I checked
the timing here and it takes gdbserver roughly 25 seconds to start in
this scenario.  Subsequent gdbserver starts in the same test run take
less time and usually complete within 10 seconds although occasionally
`target remote ...' precedes the corresponding `Listening on port...'
message again.

Therefore I have fixed this problem by setting an explicit timeout to
120s on the expect call in question.  If this turns out too arbitrary
sometime, then perhaps a separate `gdbserver_timeout' setting might be
due.

	* lib/gdbserver-support.exp (gdbserver_start): Set timeout to
	120 on waiting for the TCP socket to open.
gdbserver-support: Handle gdbserver start failures

As it happens we have a board that fails a gdb.base/gcore-relro.exp
test case reproducibly and moreover the case appears to trigger a
kernel bug making the it less than usable.  Specifically the board
remains responsive to some extent, however processes do not appear
to be able to successfully complete termination anymore and perhaps
more importantly further gdbserver processes can be started, but they
never reach the stage of listening on the RSP socket.

This change handles timeouts in gdbserver start properly, by throwing
a TCL error exception when gdbserver does not report listening on the
RSP socket in time.  This is then caught at the outer level and
reported, and 2 rather than 1 is returned so that the caller may tell
the failure to start gdbserver and other issues apart and act
accordingly (or do nothing).

I thought letting the exception unwind further on might be a good idea
for any test harnesses out there to break outright where a gdbserver
start error is silently ignored right now, however I figured out the
calls to gdbserver-support.exp are buried down too deep in the GDB test
suite for such a change to be made easily.  I think returning a distinct
return value is good enough (the API says "non-zero", so 2 is as good as
1) and we can always make the error harder in a later step if required.

With config/gdbserver.exp being used this change remains transparent
to the target board, the return value is passed up by gdb_reload and
the error exception unwinds through gdbserver_gdb_load and is caught
and handled by mi_gdb_target_load.  A call to perror is still made,
reporting the timeout, and in the case of mi_gdb_target_load the
procedure returns a value denoting unsuccessful completion.  An
unsuccessful completion of gdb_reload is already handled elsewhere.

An alternative gdbserver board configuration can interpret the return
value in its gdb_reload implementation and catch the error in
gdbserver_gdb_load in an attempt to recover a target board that has
gone astray, for example by rebooting the board somehow.  This has
proved effective with our failing board, that now completes the
remaining test cases with no further hiccups.

	* lib/gdbserver-support.exp (gdbserver_start): Throw an error
	exception on timeout.
	(gdbserver_run): Catch any `gdbserver_spawn' error exceptions.
	(gdbserver_start_extended): Catch any `gdbserver_start' error
	exceptions.
	(gdbserver_start_multi, mi_gdbserver_start_multi): Likewise.
	* lib/mi-support.exp (mi_gdb_target_load): Catch any
	`gdbserver_gdb_load' error exceptions.
Remove trad_frame_set_reg_unknown declaration

The trad_frame_set_reg_unknown declaration was added in commit
0db9b4b70969 (March 2004), but apparently never defined or referenced.

gdb/ChangeLog:

	* trad-frame.h (trad_frame_set_reg_unknown): Remove declaration.
GDB/testsuite: Avoid timeout lowering

The recent change to introduce `gdb_reverse_timeout' turned out
ineffective for board setups that set the `gdb,timeout' target variable.
A lower `gdb,timeout' setting takes precedence and defeats the effect of
`gdb_reverse_timeout'.  This is because the global timeout is overridden
in gdb_test_multiple and then again in gdb_expect.

Three timeout variables are taken into account in these two places, in
this precedence:

1. The `gdb,timeout' target variable.

2. The caller's local `timeout' variable (upvar timeout)

3. The global `timeout' variable.

This precedence is obeyed by gdb_test_multiple strictly.  OTOH
gdb_expect will select the higher of the two formers and will only take
the latter into account if none of the formers is present.  However the
two timeout selections are conceptually the same and gdb_test_multiple
does its only for the purpose of passing it down to gdb_expect.

Therefore I decided there is no point to keep carrying on this
duplication and removed the sequence from gdb_test_multiple, however
retaining the `upvar timeout' variable definition.  This way gdb_expect
will still access gdb_test_multiple's caller `timeout' variable (if any)
via its own `upvar timeout' reference.

Now as to the sequence in gdb_expect.  In addition to the three
variables described above it also takes a timeout argument into account,
as the fourth value to choose from.  It is currently used if it is
higher than the timeout selected from the variables as described above.

With the timeout selection code from gdb_test_multiple gone, gone is
also the most prominent use of this timeout argument, it's now used in
a couple of places only, mostly within this test framework library code
itself for preparatory commands or suchlike.  With this being the case
this timeout selection code can be simplified as follows:

1. Among the three timeout variables, the highest is always chosen.
   This is so that a test case doesn't inadvertently lower a high value
   timeout needed by slow target boards.  This is what all test cases
   use.

2. Any timeout argument takes precedence.  This is for special cases
   such as within the framework library code, e.g. it doesn't make sense
   to send `set height 0' with a timeout of 7200 seconds.  This is a
   local command that does not interact with the target and setting a
   high timeout here only risks a test suite run taking ages if it goes
   astray for some reason.

3. The fallback timeout of 60s remains.

	* lib/gdb.exp (gdb_test_multiple): Remove code to select the
	timeout, don't pass one down to gdb_expect.
	(gdb_expect): Rework timeout selection.
GDB/testsuite: Add/correct gdb.reverse timeout tweaks

There are three cases in two scripts in the gdb.reverse subset that
take a particularly long time.  Two of them are already attempted to
take care of by extending the timeout from the default.  The remaining
one has no precautions taken.  The timeout extension is ineffective
though, it is done by adding a constant rather than by scaling and as
a result while it may work for target boards that get satisfied with
the detault test timeout of 10s, it does not serve its purpose for
slower ones.

Here are indicative samples of execution times (in seconds) observed
for these cases respectively, for an ARMv7 Panda board running Linux
and a `-march=armv5te' multilib:

PASS: gdb.reverse/sigall-reverse.exp: continue to signal exit
elapsed: 385
PASS: gdb.reverse/until-precsave.exp: run to end of main
elapsed: 4440
PASS: gdb.reverse/until-precsave.exp: save process recfile
elapsed: 965

for the same board and a `-mthumb -march=armv5te' multilib:

PASS: gdb.reverse/sigall-reverse.exp: continue to signal exit
elapsed: 465
PASS: gdb.reverse/until-precsave.exp: run to end of main
elapsed: 4191
PASS: gdb.reverse/until-precsave.exp: save process recfile
elapsed: 669

and for QEMU in the system emulation mode and a `-march=armv4t'
multilib:

PASS: gdb.reverse/sigall-reverse.exp: continue to signal exit
elapsed: 45
PASS: gdb.reverse/until-precsave.exp: run to end of main
elapsed: 433
PASS: gdb.reverse/until-precsave.exp: save process recfile
elapsed: 104

Based on the performance of other tests these two test configurations
have their default timeout set to 450s and 60s respectively.

The remaining two multilibs (`-mthumb -march=armv4t' and `-mthumb
-march=armv7-a') do not produce test results usable enough to have data
available for these cases.

 Based on these results I have tweaked timeouts for these cases as
follows.  This, together with a suitable board timeout setting, removes
timeouts for these cases.  Note that for the default timeout of 10s the
new setting for the first case in gdb.reverse/until-precsave.exp is
compatible with the old one, just a bit higher to keep the convention
of longer timeouts to remain multiples of 30s.  The second case there
does not need such a high setting so I have lowered it a bit to avoid
an unnecessary delay where this test case genuinely times out.

	* gdb.reverse/sigall-reverse.exp: Increase the timeout by
	a factor of 2 for a slow test case.  Take the `gdb,timeout'
	target setting into account for this calculation.
	* gdb.reverse/until-precsave.exp: Increase the timeout by
	a factor of 15 and 3 respectively rather than adding 120
	for a pair of slow test cases.  Take the `gdb,timeout'
	target setting into account for this calculation.
GDB/testsuite: Correct gdb.base/watchpoint-solib.exp timeout tweak

Similarly to the previous changes to gdb.reverse/sigall-reverse.exp and
gdb.reverse/until-precsave.exp this corrects the timeout tweak in
gdb.base/watchpoint-solib.exp.

This test case executes a large amount of code with a software watchpoint
enabled.  This means single-stepping all the way through and takes a lot
of time, e.g. for an ARMv7 Panda board and a `-march=armv5te' multilib:

PASS: gdb.base/watchpoint-solib.exp: continue to foo again
elapsed: 714

for the same board and a `-mthumb -march=armv5te' multilib:

PASS: gdb.base/watchpoint-solib.exp: continue to foo again
elapsed: 1275

and for QEMU in the system emulation mode and a `-march=armv4t'
multilib:

PASS: gdb.base/watchpoint-solib.exp: continue to foo again
elapsed: 115

(values in seconds) -- all of which having the default timeout of 60s,
set based on the requirement of the remaining test cases (other than
gdb.reverse ones).

Here again the timeout extension to have a meaning should be calculated
by scaling rather than using an arbitrary constant, and a larger factor
of 30 will do, leaving some margin.  Hopefully for everyone or otherwise
we'll probably have to come up with a smarter solution.

OTOH the other test cases in this script do not require the extension so
they can be moved outside its umbrella so as to avoid unnecessary delays
if something goes wrong and a genuine timeout triggers.

	* gdb.base/watchpoint-solib.exp: Increase the timeout by a factor
	of 30 rather than hardcoding 120 for a slow test case.  Take the
	`gdb,timeout' target setting into account for this calculation.
	Don't extend the timeout for the test cases that don't need it.
Add myself as write-after-approval GDB maintainer

gdb/ChangeLog:

	* MAINTAINERS (Write After Approval): Add "James Hogan".
MIPS: Don't infer IRIX OS ABI from generic section names

There are `.MIPS.abiflags', `.MIPS.options' and `.MIPS.stubs' sections
also present in Linux executables, so we can't infer IRIX OS ABI solely
from the existence of these sections.  This is not going to be a problem
as there are bound to be other sections whose names start with `.MIPS.'
in IRIX executables and this selection only matters for a non-default OS
ABI in a multiple-target GDB executable.  As a last resort the automatic
selection can be overridden with `set osabi'.

	* mips-irix-tdep.c (mips_irix_elf_osabi_sniff_abi_tag_sections):
	Exclude `.MIPS.abiflags', `.MIPS.options' and `.MIPS.stubs' from
	the list of sections determining GDB_OSABI_IRIX.
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