These are useless because they can't match any address. In fact,
worse than useless because the .eh_frame_hdr lookup table matching
addresses to FDEs does not contain information about the FDE range.
The table is sorted by address; Range is inferred by the address
delta from one entry to the next. So if a zero address range FDE is
followed by a normal non-zero range FDE for the same address,
everything is good. However, the qsort could just as easily sort the
FDEs in the other order, in which case the normal FDE would
effectively be seen to have a zero range.
bfd/
PR 17447
* elf-bfd.h (struct eh_cie_fde): Comment re NULL u.fde.cie_inf.
* elf-eh-frame.c (_bfd_elf_parse_eh_frame): Mark zero address
range FDEs for discarding.
(vma_compare): Sort on range after address.
(_bfd_elf_gc_mark_fdes): Test for NULL u.fde.cie_inf.
(_bfd_elf_discard_section_eh_frame): Likewise. Write "FDE" in
error message rather than "fde".
(_bfd_elf_write_section_eh_frame_hdr): Write "PC" and "FDE" in
error message.
ld/testsuite/
* ld-elf/eh1.s: Don't create FDEs with zero address ranges.
* ld-elf/eh3.s: Likewise.
* ld-elf/eh1.d, * ld-elf/eh2.d, * ld-elf/eh3.d: Adjust.
* ld-mips-elf/eh-frame1-n32.d: Warning match update.
* ld-mips-elf/eh-frame1-n64.d: Likewise.
* ld-mips-elf/eh-frame2-n32.d: Likewise.
* ld-mips-elf/eh-frame2-n64.d: Likewise.
This patch was committed to GCC trunk as revision 215865.
2014-10-03 Jing Yu <jingyu@google.com>
* configure.ac: Add aarch64 to list of targets that support gold.
* configure: Regenerate.
In installing minimal symbols for ELF shared library trampolines
we "forget" to make individual symbols special where required. This
leads to problems on the MIPS target using microMIPS SVR4 lazy stubs.
Lacking the special annotation these stubs are treated as standard
MIPS code and this makes GDB insert the wrong software breakpoint
instruction, breaking e.g. single-stepping through these stubs. This
is not a very frequent scenario as microMIPS SVR4 lazy stubs are
typically only used in shared libraries with the main executable
using PLT, handled elsewhere. Still it triggers e.g. when a software
watchpoint has been installed. The symptom is SIGILL or the program
going astray, depending on the endianness. Disassembly of these stubs
is also wrong.
* elfread.c (elf_symtab_read): Also mark solib trampoline minimal
symbols special.
This change:
commit b775012e84
Author: Luis Machado <luisgpm@br.ibm.com>
Date: Fri Feb 24 15:10:59 2012 +0000
2012-02-24 Luis Machado <lgustavo@codesourcery.com>
* remote.c (remote_supports_cond_breakpoints): New forward
declaration.
[...]
changed the way breakpoints are inserted and removed such that
`insert_bp_location' can now be called with the breakpoint being handled
already in place, while previously the call was only ever made for
breakpoints that have not been put in place. This in turn caused an
issue for software breakpoints and targets for which a breakpoint's
`placed_address' may not be the same as the original requested address.
The issue is `insert_bp_location' overwrites the previously adjusted
value in `placed_address' with the original address, that is only
replaced back with the correct adjusted address later on when
`gdbarch_breakpoint_from_pc' is called. Meanwhile there's a window
where the value in `placed_address' does not correspond to data stored
in `shadow_contents', leading to incorrect instruction bytes being
supplied when `one_breakpoint_xfer_memory' is called to supply the
instruction overlaid by the breakpoint.
And this is exactly what happens on the MIPS target with software
breakpoints placed in microMIPS code. In this case not only
`placed_address' is not the original address because of the ISA bit, but
`mips_breakpoint_from_pc' has to read the original instruction to
determine which one of the two software breakpoint instruction encodings
to choose as well. The 16-bit encoding is used to replace 16-bit
instructions and similarly the 32-bit one is used with 32-bit
instructions, to satisfy branch delay slot size requirements.
The mismatch between `placed_address' and the address data in
`shadow_contents' has been obtained from leads to the wrong encoding
being used in some cases, which in the case of a 32-bit software
breakpoint instruction replacing a 16-bit instruction causes corruption
to the adjacent following instruction and leads the debug session astray
if execution reaches there e.g. with a jump.
To address this problem I made the change below, that adds a
`reqstd_address' field to `struct bp_target_info' and leaves
`placed_address' unchanged once it has been set. This ensures data in
`shadow_contents' is always consistent with `placed_address'.
This approach also has this good side effect that all the places that
examine the breakpoint's address see a consistent value, either
`reqstd_address' or `placed_address', as required. Currently some
places see either the original or the adjusted address in
`placed_address', depending on whether they have been called before
`gdbarch_remote_breakpoint_from_pc' or afterwards. This is in
particular true for subsequent calls to
`gdbarch_remote_breakpoint_from_pc' itself, e.g. from
`one_breakpoint_xfer_memory'. This is also important for places like
`find_single_step_breakpoint' where a breakpoint's address is compared
to the raw value of $pc.
* breakpoint.h (bp_target_info): Add `reqstd_address' member,
update comments.
* breakpoint.c (one_breakpoint_xfer_memory): Use `reqstd_address'
for the breakpoint's address. Don't preinitialize `placed_size'.
(insert_bp_location): Set `reqstd_address' rather than
`placed_address'.
(bp_target_info_copy_insertion_state): Also copy `placed_address'.
(bkpt_insert_location): Use `reqstd_address' for the breakpoint's
address.
(bkpt_remove_location): Likewise.
(deprecated_insert_raw_breakpoint): Likewise.
(deprecated_remove_raw_breakpoint): Likewise.
(find_single_step_breakpoint): Likewise.
* mem-break.c (default_memory_insert_breakpoint): Use
`reqstd_address' for the breakpoint's address. Don't set
`placed_address' or `placed_size' if breakpoint contents couldn't
have been determined.
* remote.c (remote_insert_breakpoint): Use `reqstd_address' for
the breakpoint's address.
(remote_insert_hw_breakpoint): Likewise. Don't set
`placed_address' or `placed_size' if breakpoint couldn't have been
set.
* aarch64-linux-nat.c (aarch64_linux_insert_hw_breakpoint): Use
`reqstd_address' for the breakpoint's address.
* arm-linux-nat.c (arm_linux_hw_breakpoint_initialize): Likewise.
* ia64-tdep.c (ia64_memory_insert_breakpoint): Likewise.
* m32r-tdep.c (m32r_memory_insert_breakpoint): Likewise.
* microblaze-linux-tdep.c
(microblaze_linux_memory_remove_breakpoint): Likewise.
* monitor.c (monitor_insert_breakpoint): Likewise.
* nto-procfs.c (procfs_insert_breakpoint): Likewise.
(procfs_insert_hw_breakpoint): Likewise.
* ppc-linux-nat.c (ppc_linux_insert_hw_breakpoint): Likewise.
* ppc-linux-tdep.c (ppc_linux_memory_remove_breakpoint): Likewise.
* remote-m32r-sdi.c (m32r_insert_breakpoint): Likewise.
* remote-mips.c (mips_insert_breakpoint): Likewise.
* x86-nat.c (x86_insert_hw_breakpoint): Likewise.
On MIPS64 little endian, attempting an assignment to a bit field
that lives in a register yields the wrong result. It just corrupts
the data in the register depending on the specific position of the
bit field inside the structure.
FAIL: gdb.base/store.exp: f_1.j
FAIL: gdb.base/store.exp: f_1.k
FAIL: gdb.base/store.exp: F_1.i
FAIL: gdb.base/store.exp: F_1.j
FAIL: gdb.base/store.exp: F_1.k
FAIL: gdb.base/store.exp: f_2.j
FAIL: gdb.base/store.exp: f_2.k
FAIL: gdb.base/store.exp: F_2.i
FAIL: gdb.base/store.exp: F_2.j
FAIL: gdb.base/store.exp: F_2.k
FAIL: gdb.base/store.exp: f_3.j
FAIL: gdb.base/store.exp: f_3.k
FAIL: gdb.base/store.exp: F_3.i
FAIL: gdb.base/store.exp: F_3.j
FAIL: gdb.base/store.exp: F_3.k
FAIL: gdb.base/store.exp: f_4.j
FAIL: gdb.base/store.exp: f_4.k
FAIL: gdb.base/store.exp: F_4.i
FAIL: gdb.base/store.exp: F_4.j
FAIL: gdb.base/store.exp: F_4.k
=== gdb Summary ===
Now, GDB knows how to do bit field assignment properly, but MIPS is
one of those architectures that uses a hook for the register-to-value
conversion. Although we can properly tell when the type being passed
is a structure or union, we cannot tell when it is a bit field,
because the bit field data lives in a value structure. Such data
only lives in a "type" structure when the parent structure is being
referenced, thus you can collect them from the flds_bnds members.
A bit field type structure looks pretty much the same as any other
primitive type like int or char, so we can't distinguish them.
Forcing more fields into the type structure wouldn't help much,
because the type structs are shared.
2014-10-03 Luis Machado <lgustavo@codesourcery.com>
* valops.c (value_assign): Check for bit field assignments
before calling architecture-specific register value
conversion functions.
Trying to debug gdb with itself,
I stumbled on the following complaints
Unknown symbol type 0x2e
or
Unknown symbol type 0x4e
It appears that those corrspond to N_BNSYM and N_ENSYM,
which are MacOS extensions of stabs debugging format.
But these extensions have been used inside gcc probalby
for a while already, see:
https://gcc.gnu.org/ml/gcc/2004-08/msg00157.html
As the only purpose of these entries is to allow for removal
of stabs information if the function is removed,
it can be safely ignored by GDB.
This patch simply adds those two entry types to the list
of ignored entry type in read_dbx_symtab function.
Is this OK?
Pierre Muller
2014-10-03 Pierre Muller <muller@sourceware.org>
* dbxread.c (read_dbx_symtab): Also ignore N_BNSYM/N_ENSYM.
In git b57bacec, I said:
> With that in place, the need to delay "Program received signal FOO"
> was actually caught by the manythreads.exp test. Without that bit, I
> was getting:
>
> [Thread 0x7ffff7f13700 (LWP 4499) exited]
> [New Thread 0x7ffff7f0b700 (LWP 4500)]
> ^C
> Program received signal SIGINT, Interrupt.
> [New Thread 0x7ffff7f03700 (LWP 4501)] <<< new output
> [Switching to Thread 0x7ffff7f0b700 (LWP 4500)]
> __GI___nptl_death_event () at events.c:31
> 31 {
> (gdb) FAIL: gdb.threads/manythreads.exp: stop threads 1
>
> That is, I was now getting "New Thread" lines after the "Program
> received signal" line, and the test doesn't expect them. As the
> number of new threads discovered before and after the "Program
> received signal" output is unbounded, it's much nicer to defer
> "Program received signal" until after synching the thread list, thus
> close to the "switching to thread" output and "current frame/source"
> info:
>
> [Thread 0x7ffff7863700 (LWP 7647) exited]
> ^C[New Thread 0x7ffff786b700 (LWP 7648)]
>
> Program received signal SIGINT, Interrupt.
> [Switching to Thread 0x7ffff7fc4740 (LWP 6243)]
> __GI___nptl_create_event () at events.c:25
> 25 {
> (gdb) PASS: gdb.threads/manythreads.exp: stop threads 1
This commit factors out the two places in the test that are effected
by this, and adds there a destilled version of the comment above.
gdb/testsuite/
2014-10-02 Pedro Alves <palves@redhat.com>
* gdb.threads/manythreads.exp (interrupt_and_wait): New procedure.
(top level) <stop threads 1, stop threads 2>: Use it.
Commit a25a5a45 (Fix "breakpoint always-inserted off"; remove
"breakpoint always-inserted auto") regressed non-stop remote
debugging.
This was exposed by mi-nsintrall.exp intermittently failing with a
spurious SIGTRAP.
The problem is that when debugging with "target remote", new threads
the target has spawned but have never reported a stop aren't visible
to GDB until it explicitly resyncs its thread list with the target's.
For example, in a program like this:
int
main (void)
{
pthread_t child_thread;
pthread_create (&child_thread, NULL, child_function, NULL);
return 0; <<<< set breakpoint here
}
If the user sets a breakpoint at the "return" statement, and runs the
program, when that breakpoint hit is reported, GDB is only aware of
the main thread. So if we base the decision to remove or insert
breakpoints from the target based on whether all the threads we know
about are stopped, we'll miss that child_thread is running, and thus
we'll remove breakpoints from the target, even through they should
still remain inserted, otherwise child_thread will miss them.
The break-while-running.exp test actually should also be exposing this
thread-list-out-of-synch problem. That test sets a breakpoint while
the main thread is stopped, but other threads are running. Because
other threads are running, the breakpoint is supposed to be inserted
immediately. But, unless something forces a refetch of the thread
list, like, e.g., "info threads", GDB won't be aware of the other
threads that had been spawned by the main thread, and so won't insert
new or old breakpoints in the target. And it turns out that the test
is exactly doing an explicit "info threads", masking out the
problem... This commit adjust the test to exercise the case of not
issuing "info threads". The test then fails without the GDB fix.
In the ni-nsintrall.exp case, what happens is that several threads hit
the same breakpoint, and when the first thread reports the stop,
because GDB wasn't aware other threads exist, all threads known to GDB
are found stopped, so GDB removes the breakpoints from the target.
The other threads follow up with SIGTRAPs too for that same
breakpoint, which has already been removed. For the first few
threads, the moribund breakpoints machinery suppresses the SIGTRAPs,
but after a few events (precisely '3 * thread_count () + 1' at the
time the breakpoint was removed, see update_global_location_list), the
moribund breakpoint machinery is no longer aware of the removed
breakpoint, and the SIGTRAP is reported as a spurious stop.
The fix is naturally then to stop assuming that if no thread in the
list is executing, then the target is fully stopped. We can't know
that until we fully sync the thread list. Because updating the thread
list on every stop would be too much RSP traffic, I chose instead to
update it whenever we're about to present a stop to the user.
Actually updating the thread list at that point happens to be an item
I had added to the local/remote parity wiki page a while ago:
Native GNU/Linux debugging adds new threads to the thread list as
the program creates them "The [New Thread foo] messages". Remote
debugging can't do that, and it's arguable whether we shouldn't even
stop native debugging from doing that, as it hinders inferior
performance. However, a related issue is that with remote targets
(and gdbserver), even after the program stops, the user still needs
to do "info threads" to pull an updated thread list. This, should
most likely be addressed, so that GDB pulls the list itself, perhaps
just before presenting a stop to the user.
With that in place, the need to delay "Program received signal FOO"
was actually caught by the manythreads.exp test. Without that bit, I
was getting:
[Thread 0x7ffff7f13700 (LWP 4499) exited]
[New Thread 0x7ffff7f0b700 (LWP 4500)]
^C
Program received signal SIGINT, Interrupt.
[New Thread 0x7ffff7f03700 (LWP 4501)] <<< new output
[Switching to Thread 0x7ffff7f0b700 (LWP 4500)]
__GI___nptl_death_event () at events.c:31
31 {
(gdb) FAIL: gdb.threads/manythreads.exp: stop threads 1
That is, I was now getting "New Thread" lines after the "Program
received signal" line, and the test doesn't expect them. As the
number of new threads discovered before and after the "Program
received signal" output is unbounded, it's much nicer to defer
"Program received signal" until after synching the thread list, thus
close to the "switching to thread" output and "current frame/source"
info:
[Thread 0x7ffff7863700 (LWP 7647) exited]
^C[New Thread 0x7ffff786b700 (LWP 7648)]
Program received signal SIGINT, Interrupt.
[Switching to Thread 0x7ffff7fc4740 (LWP 6243)]
__GI___nptl_create_event () at events.c:25
25 {
(gdb) PASS: gdb.threads/manythreads.exp: stop threads 1
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/
2014-10-02 Pedro Alves <palves@redhat.com>
* breakpoint.c (breakpoints_should_be_inserted_now): Use
threads_are_executing.
* breakpoint.h (breakpoints_should_be_inserted_now): Add
describing comment.
* gdbthread.h (threads_are_executing): Declare.
(handle_signal_stop) <random signals>: Don't print about the
signal here if stopping.
(end_stepping_range): Don't notify observers here.
(normal_stop): Update the thread list. If stopped by a random
signal or a stepping range ended, notify observers.
* thread.c (threads_executing): New global.
(init_thread_list): Clear 'threads_executing'.
(set_executing): Set or clear 'threads_executing'.
(threads_are_executing): New function.
(update_threads_executing): New function.
(update_thread_list): Use it.
gdb/testsuite/
2014-10-02 Pedro Alves <palves@redhat.com>
* gdb.threads/break-while-running.exp (test): Add new
'update_thread_list' argument. Skip "info threads" if false.
(top level): Add new 'update_thread_list' axis.
Following an exec with "breakpoint always-inserted on" tries to insert
breakpoints in the new image at the addresses the symbols had in the
old image.
With "always-inserted off", we see:
gdb gdb.multi/multi-arch-exec -ex "set breakpoint always-inserted off"
GNU gdb (GDB) 7.8.50.20140924-cvs
...
(gdb) b main
Breakpoint 1 at 0x400664: file gdb.multi/multi-arch-exec.c, line 24.
^^^^^^^^
(gdb) c
The program is not being run.
(gdb) r
Starting program: testsuite/gdb.multi/multi-arch-exec
Breakpoint 1, main () at gdb/testsuite/gdb.multi/multi-arch-exec.c:24
24 execl (BASEDIR "/multi-arch-exec-hello",
(gdb) c
Continuing.
process 9212 is executing new program: gdb/testsuite/gdb.multi/multi-arch-exec-hello
Breakpoint 1, main () at gdb/testsuite/gdb.multi/hello.c:40
40 bar();
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y 0x080484e4 in main at gdb/testsuite/gdb.multi/hello.c:40
^^^^^^^^^^
breakpoint already hit 2 times
(gdb)
Note how main was 0x400664 in multi-arch-exec, and 0x080484e4 in
gdb.multi/hello.
With "always-inserted on", we get:
Breakpoint 1, main () at gdb/testsuite/gdb.multi/multi-arch-exec.c:24
24 execl (BASEDIR "/multi-arch-exec-hello",
(gdb) c
Continuing.
infrun: target_wait (-1, status) =
infrun: 9444 [process 9444],
infrun: status->kind = execd
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_EXECD
Warning:
Cannot insert breakpoint 1.
Cannot access memory at address 0x400664
(gdb)
That is, GDB is trying to insert a breakpoint at 0x400664, after the
exec, and then that address happens to not be mapped at all in the new
image.
The problem is that update_breakpoints_after_exec is creating
breakpoints, which ends up in update_global_location_list immediately
inserting breakpoints if "breakpoints always-inserted" is "on".
update_breakpoints_after_exec is called very early when we see an exec
event. At that point, we haven't loaded the symbols of the new
post-exec image yet, and thus haven't reset breakpoint's addresses to
whatever they may be in the new image. All we should be doing in
update_breakpoints_after_exec is deleting breakpoints that no longer
make sense after an exec. So the fix removes those breakpoint
creations.
The question is then, if not here, where are those breakpoints
re-created? Turns out we don't need to do anything else, because at
the end of follow_exec, we call breakpoint_re_set, whose tail is also
creating exactly the same breakpoints update_breakpoints_after_exec is
currently creating:
breakpoint_re_set (void)
{
...
create_overlay_event_breakpoint ();
create_longjmp_master_breakpoint ();
create_std_terminate_master_breakpoint ();
create_exception_master_breakpoint ();
}
A new test is added to exercise this.
Tested on x86_64 Fedora 20.
gdb/
2014-10-02 Pedro Alves <palves@redhat.com>
PR breakpoints/17431
* breakpoint.c (update_breakpoints_after_exec): Don't create
overlay, longjmp, std terminate nor exception breakpoints here.
gdb/testsuite/
2014-10-02 Pedro Alves <palves@redhat.com>
PR breakpoints/17431
* gdb.base/execl-update-breakpoints.c: New file.
* gdb.base/execl-update-breakpoints.exp: New file.
A patch I wrote made GDB pull the thread list sooner when debugging
with target remote, and I noticed an intended consequence. GDB
started bouncing around the currently selected remote/general thread
more frequently. E.g.:
Sending packet: $qTMinFTPILen#3b...Packet received: 5
+Sending packet: $Hgp726d.726d#53...Packet received: OK
Sending packet: $m400680,40#2f...Packet received: 85c0741455bff00d60004889e5ffd05de97bffffff0f1f00e973ffffff0f1f00554889e5c745fc00000000c745fc01000000e900000000c745fc02000000b800
+Sending packet: $Hgp726d.7278#28...Packet received: OK
Sending packet: $m4006b2,1#28...Packet received: e9
Fast tracepoint 2 at 0x4006b2: file gdb/testsuite/gdb.trace/range-stepping.c, line 53.
Sending packet: $qTStatus#49...Packet received: T0;tnotrun:0;tframes:0;tcreated:0;tfree:500000;tsize:500000;circular:0;disconn:0;starttime:0;stoptime:0;username:;notes::
This ended up breaking "tstart" when one has fast tracepoints set,
because gdbserver isn't expecting an Hg packet in response to
qRelocInsn:
(gdb) ftrace *set_point
Fast tracepoint 3 at 0x4006b2: file gdb/testsuite/gdb.trace/range-stepping.c, line 53.
(gdb) PASS: gdb.trace/range-stepping.exp: ftrace: ftrace *set_point
tstart
gdbserver: Malformed response to qRelocInsn, ignoring: Hgp2783.2783
Target does not support this command.
(gdb) FAIL: gdb.trace/range-stepping.exp: ftrace: tstart
remote_trace_start should probably start by making sure the remote
current thread matches inferior_ptid (calling set_general_thread), but
still, reducing unnecessary bouncing is a good idea. It happens
because the memory/symbol/breakpoint routines use
switch_to_program_space_and_thread to do something in the right
context and then revert back to the previously current thread.
The fix is to simply make any_thread_of_process,
find_inferior_for_program_space, etc. give preference to the current
thread/inferior it if matches.
gdb/
2014-10-02 Pedro Alves <palves@redhat.com>
* gdbthread.h (any_thread_of_process, any_live_thread_of_process):
Adjust comments.
* inferior.c (find_inferior_for_program_space): Give preference to
the current inferior.
* inferior.h (find_inferior_for_program_space): Update comment.
* progspace.c (switch_to_program_space_and_thread): Prefer the
current inferior if it's bound to the program space requested. If
the inferior found doesn't have a PID yet, don't bother looking up
a thread.
* progspace.h (switch_to_program_space_and_thread): Adjust
comment.
* thread.c (any_thread_of_process, any_live_thread_of_process):
Give preference to the current thread.
Currently, with "set breakpoint auto-hw off", we'll still try to
insert a software breakpoint at addresses covered by supposedly
read-only or inacessible regions:
(top-gdb) mem 0x443000 0x450000 ro
(top-gdb) set mem inaccessible-by-default off
(top-gdb) disassemble
Dump of assembler code for function main:
0x0000000000443956 <+34>: movq $0x0,0x10(%rax)
=> 0x000000000044395e <+42>: movq $0x0,0x18(%rax)
0x0000000000443966 <+50>: mov -0x24(%rbp),%eax
0x0000000000443969 <+53>: mov %eax,-0x20(%rbp)
End of assembler dump.
(top-gdb) b *0x0000000000443969
Breakpoint 5 at 0x443969: file ../../src/gdb/gdb.c, line 29.
(top-gdb) c
Continuing.
warning: cannot set software breakpoint at readonly address 0x443969
Breakpoint 5, 0x0000000000443969 in main (argc=1, argv=0x7fffffffd918) at ../../src/gdb/gdb.c:29
29 args.argc = argc;
(top-gdb)
We warn, saying that the insertion can't be done, but then proceed
attempting the insertion anyway, and in case of manually added
regions, the insert actually succeeds.
This is a regression; GDB used to fail inserting the breakpoint. More
below.
I stumbled on this as I wrote a test that manually sets up a read-only
memory region with the "mem" command, in order to test GDB's behavior
with breakpoints set on read-only regions, even when the real memory
the breakpoints are set at isn't really read-only. I wanted that in
order to add a test that exercises software single-stepping through
read-only regions.
Note that the memory regions that target_memory_map returns aren't
like e.g., what would expect to see in /proc/PID/maps on Linux.
Instead, they're the physical memory map from the _debuggers_
perspective. E.g., a read-only region would be real ROM or flash
memory, while a read-only+execute mapping in /proc/PID/maps is still
read-write to the debugger (otherwise the debugger wouldn't be able to
set software breakpoints in the code segment).
If one tries to manually write to memory that falls within a memory
region that is known to be read-only, with e.g., "p foo = 1", then we
hit a check in memory_xfer_partial_1 before the write mananges to make
it to the target side.
But writing a software/memory breakpoint nowadays goes through
target_write_raw_memory, and unlike when writing memory with
TARGET_OBJECT_MEMORY, nothing on the TARGET_OBJECT_RAW_MEMORY path
checks whether we're trying to write to a read-only region.
At the time "breakpoint auto-hw" was added, we didn't have the
TARGET_OBJECT_MEMORY vs TARGET_OBJECT_RAW_MEMORY target object
distinction yet, and the code path in memory_xfer_partial that blocks
writes to read-only memory was hit for memory breakpoints too. With
GDB 6.8 we had:
warning: cannot set software breakpoint at readonly address 0000000000443943
Warning:
Cannot insert breakpoint 1.
Error accessing memory address 0x443943: Input/output error.
So I started out by fixing this by adding the memory region validation
to TARGET_OBJECT_RAW_MEMORY too.
But later, when testing against GDBserver, I realized that that would
only block software/memory breakpoints GDB itself inserts with
gdb/mem-break.c. If a target has a to_insert_breakpoint method, the
insertion request will still pass through to the target. So I ended
up converting the "cannot set breakpoint" warning in breakpoint.c to a
real error return, thus blocking the insertion sooner.
With that, we'll end up no longer needing the TARGET_OBJECT_RAW_MEMORY
changes once software single-step breakpoints are converted to real
breakpoints. We need them today as software single-step breakpoints
bypass insert_bp_location. But, it'll be best to leave that in as
safeguard anyway, for other direct uses of TARGET_OBJECT_RAW_MEMORY.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/
2014-10-01 Pedro Alves <palves@redhat.com>
* breakpoint.c (insert_bp_location): Error out if inserting a
software breakpoint at a read-only address.
* target.c (memory_xfer_check_region): New function, factored out
from ...
(memory_xfer_partial_1): ... this. Make the 'reg_len' local a
ULONGEST.
(target_xfer_partial) <TARGET_OBJECT_RAW_MEMORY>: Check the access
against the memory region attributes.
gdb/testsuite/
2014-10-01 Pedro Alves <palves@redhat.com>
* gdb.base/breakpoint-in-ro-region.c: New file.
* gdb.base/breakpoint-in-ro-region.exp: New file.
Don't reset the exit code at inferior exit and print it in
-list-thread-groups.
gdb/ChangeLog:
* NEWS: Announce new exit-code field in -list-thread-groups
output.
* inferior.c (exit_inferior_1): Don't clear exit code.
(inferior_appeared): Clear exit code.
* mi/mi-main.c (print_one_inferior): Add printing of the exit
code.
gdb/testsuite/ChangeLog:
* gdb.mi/mi-exit-code.exp: New file.
* gdb.mi/mi-exit-code.c: New file.
gdb/doc/ChangeLog:
* gdb.texinfo (Miscellaneous gdb/mi Commands): Document new
exit-code field in -list-thread-groups output.
This makes it easier to rebuild all GDB's generated target description
C files.
It also clarifies the comments a bit. One might think we need a GDB
configured for the particular arquitecture (--target=foo). But a
build that includes support for the target description is sufficient.
(GDB rejects target descriptions that explicitly specify the
architecture, with an <architecture> element, if the architecture is
unknown.)
Tested that "make clean-cfiles" deletes all .c files under
src/gdb/features/, and that "make cfiles" generates them all without
error, and that diffing the newly generated C files against master
comes out an empty diff.
gdb/
2014-10-01 Pedro Alves <palves@redhat.com>
* features/Makefile: Update comments.
(XMLTOC): List all xml files we build C files from.
(clean-cfiles): New rule.
I regenerated all the .c files under src/gdb/features/ and this is
what I got.
gdb/
2014-10-01 Pedro Alves <palves@redhat.com>
* features/i386/amd64-avx512-linux.c: Regenerate.
* features/i386/amd64-avx512.c: Regenerate.
* features/i386/x32-avx512-linux.c: Regenerate.
* features/i386/x32-avx512.c: Regenerate.
The only reason .dat files exist is for GBBserver to use them in its
build system.
A few .dat files are listed as targets for generation that shouldn't.
The target descriptions these files are built from aren't used by
GDBserver. They're fallback descriptions GDB itself has baked in.
Remove them from the list of .dat files to be generated, otherwise a
plain "make" under src/gdb/features/ generates new .dat files that
aren't even in the tree today.
gdb/
2014-10-01 Pedro Alves <palves@redhat.com>
* features/Makefile (WHICH): Remove arm-with-m,
arm-with-m-fpa-layout and arm-with-m-vfp-d16.
So that we can do "make clean all" to regenerate all the renerated
.dat files.
gdb/
2014-10-01 Pedro Alves <palves@redhat.com>
* features/Makefile (clean): New rule.
This file's format is invalid, as it's missing some end quotes.
I noticed this because I tried to regenerate all the .dat files in
gdb/regformats/. I got:
sh ../../move-if-change ../regformats/i386/x32-avx.tmp ../regformats/i386/x32-avx.dat
echo "# DO NOT EDIT: generated from i386/x32-avx512.xml" > ../regformats/i386/x32-avx512.tmp
echo "name:`echo x32-avx512 | sed 's/-/_/g'`" >> ../regformats/i386/x32-avx512.tmp
echo "xmltarget:x32-avx512.xml" >> ../regformats/i386/x32-avx512.tmp
echo "expedite:rbp,rsp,rip" \
>> ../regformats/i386/x32-avx512.tmp
xsltproc --path "/home/pedro/gdb/mygit/src/gdb/features" --xinclude number-regs.xsl i386/x32-avx512.xml | \
xsltproc sort-regs.xsl - | \
xsltproc gdbserver-regs.xsl - >> ../regformats/i386/x32-avx512.tmp
i386/64bit-avx512.xml:81: parser error : Unescaped '<' not allowed in attributes values
<reg name="zmm11h" bitsize="256" type="v2ui128/>
^
i386/64bit-avx512.xml:81: parser error : attributes construct error
<reg name="zmm11h" bitsize="256" type="v2ui128/>
^
i386/64bit-avx512.xml:81: parser error : Couldn't find end of Start Tag reg line 80
<reg name="zmm11h" bitsize="256" type="v2ui128/>
^
i386/64bit-avx512.xml:82: parser error : Unescaped '<' not allowed in attributes values
<reg name="zmm12h" bitsize="256" type="v2ui128/>
^
i386/64bit-avx512.xml:82: parser error : attributes construct error
<reg name="zmm12h" bitsize="256" type="v2ui128/>
^
...
i386/x32-avx512.xml:17: element include: XInclude error : could not load i386/64bit-avx512.xml, and no fallback was found
-:1: parser error : Document is empty
^
-:1: parser error : Start tag expected, '<' not found
^
unable to parse -
-:1: parser error : Document is empty
^
-:1: parser error : Start tag expected, '<' not found
^
unable to parse -
make: *** [../regformats/i386/x32-avx512.dat] Error 6
Interestingly, gdb/expat manages to grok the broken file.
gdb/
2014-10-01 Pedro Alves <palves@redhat.com>
* features/i386/64bit-avx512.xml (zmm10h, zmm11h, zmm12h, zmm13h)
(zmm14h): Add missing end quotes.
This reverts commit a4d9ba85 - 'AARCH64: Change cpsr type to be
64bit.'.
Even though Linux's ptrace exposes CPSR as 64-bit, CPSR is really
32-bit, and basing GDB's fundamentals on a particular OS's ptrace(2)
implementation is a bad idea.
In addition, while that commit intended to fix big endian Aarch64, it
ended up breaking floating point debugging against GDBserver, for both
big and little endian, because it changed the CPSR to be 64-bit in the
features/aarch64-core.xml file, but missed regenerating the
regformats/aarch64.dat file. If we generate it now, we see this:
diff --git c/gdb/regformats/aarch64.dat w/gdb/regformats/aarch64.dat
index afe1028..0d32183 100644
--- c/gdb/regformats/aarch64.dat
+++ w/gdb/regformats/aarch64.dat
@@ -35,7 +35,7 @@ expedite:x29,sp,pc
64:x30
64:sp
64:pc
-32:cpsr
+64:cpsr
128:v0
128:v1
128:v2
IOW, that commit left regformats/aarch64.dat still considering CPSR as
32-bits. regformats/aarch64.dat is used by GDBserver for its internal
regcache layout, and for the g/G packet register block. See the
generated aarch64.c file in GDBserver's build dir.
So the target description xml file that GDBserver reports to GDB is
now claiming that CPSR is 64-bit, but what GDBserver actually puts in
the g/G register packets is 32-bits. Because GDB thinks CPSR is
64-bit (because that's what the XML description says), GDB will be
reading the remaining 32-bit bits of CPSR out of v0 (the register
immediately afterwards), and then all the registers that follow CPSR
in the register packet end up wrong in GDB, because they're being read
from the wrong offsets...
gdb/
2014-10-01 Pedro Alves <palves@redhat.com>
* features/aarch64-core.xml (cpsr): Change back to 32-bit.
* features/aarch64.c: Regenerate.
When --hash-style-both is used, gold currently builds the sysv hash
table first, then the gnu hash table. Building the gnu hash table
renumbers the dynamic symbol table, invalidating the sysv hash
table. This patch reverses the order in which the hash tables are
build so that both hash tables are correct.
gold/
PR gold/13597
* layout.cc (Layout::create_dynamic_symtab): Build gnu-style
hash table before sysv-style hash table.
This patch reorganizes the code that implements follow-fork and
detach-on-fork in preparation for implementation of those features for the
extended-remote target. The function linux-nat.c:linux_child_follow_fork
contained target-independent code mixed in with target-dependent code. The
target-independent pieces need to be accessible for the host-side
implementation of follow-fork for extended-remote Linux targets.
The changes are fairly mechanical. A new routine, follow_fork_inferior,
is implemented in infrun.c, containing those parts of
linux_child_follow_fork that manage inferiors and the inferior list. The
parts of linux_child_follow_fork that deal with LWPs and target-specifics
were left in-place. Although the order of some operations was changed, the
resulting functionality was not.
Modifications were made to the other native target follow-fork functions,
inf_ttrace_follow_fork and inf_ptrace_follow_fork, that should allow them
to work with follow_fork_inferior. Some other adjustments were necessary
in inf-ttrace.c. The changes to inf-ttrace.c and inf-ptrace.c were not
tested.
gdb/ChangeLog:
* inf-ptrace.c (inf_ptrace_follow_fork): Remove target-independent
code so as to work with follow_fork_inferior.
* inf-ttrace.c (inf_ttrace_follow_fork): Ditto.
(inf_ttrace_create_inferior): Remove reference to
inf_ttrace_vfork_ppid.
(inf_ttrace_attach): Ditto.
(inf_ttrace_detach): Ditto.
(inf_ttrace_kill): Use current_inferior instead of
inf_ttrace_vfork_ppid.
(inf_ttrace_wait): Eliminate use of inf_ttrace_vfork_ppid, report
TARGET_WAITKIND_VFORK_DONE event, delete HACK that switched the
inferior away from the parent.
* infrun.c (follow_fork): Call follow_fork_inferior instead of
target_follow_fork.
(follow_fork_inferior): New function.
(follow_inferior_reset_breakpoints): Make function static.
* infrun.h (follow_inferior_reset_breakpoints): Remove declaration.
* linux-nat.c (linux_child_follow_fork): Move target-independent
code to infrun.c:follow_fork_inferior.
Now that all instances of the regset_from_core_section gdbarch method
have been replaced by the new iterator method, delete the obsolete
method from the gdbarch interface. Adjust all invocations and
references to it.
gdb/ChangeLog:
* gdbarch.sh (regset_from_core_section): Remove gdbarch method.
* gdbarch.c: Regenerate.
* gdbarch.h: Likewise.
* corelow.c (sniff_core_bfd): Drop presence check for deleted
gdbarch method 'regset_from_core_section'.
(get_core_register_section): Remove handling for the case that
regset == NULL and regset_from_core_section is defined.
(get_core_registers): Drop check for deleted method.
* procfs.c (procfs_do_thread_registers): Adjust comment.
Now that all Linux targets use the regset iterator, the fall back to
the deprecated target method is dropped.
gdb/ChangeLog:
* linux-nat.c (linux_nat_collect_thread_registers): Remove.
(linux_nat_make_corefile_notes): Remove.
(linux_target_install_ops): Do not set target method
'make_corefile_notes'.
* linux-tdep.c (struct linux_corefile_thread_data)<collect>:
Remove field.
(linux_corefile_thread_callback): Instead of args->collect, call
linux_collect_thread_registers.
(linux_make_corefile_notes): Remove 'collect' parameter. Return
NULL unless there is a regset iterator.
(linux_make_corefile_notes_1): Remove.
(linux_init_abi): Replace reference to linux_make_corefile_notes_1
by linux_make_corefile_notes.
* linux-tdep.h (linux_make_corefile_notes): Remove prototype.
Now that all users of the target method 'fbsd_make_corefile_notes'
have been converted to the version in fbsd-tdep.c, the old method is
removed.
gdb/ChangeLog:
* fbsd-nat.c (find_signalled_thread, find_stop_signal)
(fbsd_collect_regset_section_cb, fbsd_make_corefile_notes):
Remove.
* fbsd-nat.h (fbsd_make_corefile_notes): Remove prototype.
For TILE-Gx GNU/Linux targets, no longer define the gdbarch method
'regset_from_core_section', but the iterator method instead.
gdb/ChangeLog:
* tilegx-linux-tdep.c (TILEGX_LINUX_SIZEOF_GREGSET): New macro.
(tilegx_regset_from_core_section): Remove.
(tilegx_iterate_over_regset_sections): New.
(tilegx_linux_init_abi): Adjust gdbarch initialization.
For Super-H targets, no longer define the gdbarch method
'regset_from_core_section', but the iterator method instead.
gdb/ChangeLog:
* sh-linux-tdep.c (sh_linux_init_abi): Set tdep fields
'sizeof_gregset' and 'sizeof_fpregset'.
* sh-tdep.c (sh_regset_from_core_section): Remove.
(sh_iterate_over_regset_sections): New.
(sh_gdbarch_init): Adjust gdbarch initialization.
* sh-tdep.h (struct gdbarch_tdep): New fields sizeof_gregset and
sizeof_fpregset.
* shnbsd-tdep.c (shnbsd_init_abi): Set tdep field
'sizeof_gregset'.
For Nios II GNU/Linux targets, no longer define the gdbarch method
'regset_from_core_section', but the iterator method instead.
gdb/ChangeLog:
* nios2-linux-tdep.c (NIOS2_GREGS_SIZE): New macro.
(nios2_regset_from_core_section): Remove.
(nios2_iterate_over_regset_sections): New.
(nios2_linux_init_abi): Adjust gdbarch initialization.
