I noticed in procfs.c that we use a static buffer for building error
strings when we could easily use std::string and string_printf to
achieve the same result, this commit does that.
I ran into this while performing a further refactor/cleanup that will
be presented in a later patch in this series, and thought this was
worth splitting out into its own patch.
As far as I can tell, only Solaris uses procfs.c, so I did a test
build on a Solaris machine, and I don't believe that I've broken
anything.
There should be no user visible changes after this commit.
Approved-By: Tom Tromey <tom@tromey.com>
While working on some other patch I noticed that in reread_symbols
there is a diagnostic message that can be printed, and in some cases
we might use the wrong filename in the message.
The code in question is checking to see if an objfile has changed on
disk, we do this by stat-ing the on disk file and checking the mtime.
If this file has been removed from disk then we print a message that
the file has been removed, however, if the objfile is within an
archive then we stat the archive itself, but then warn that the
component within the archive has disappeared. I think it makes more
sense to say that the archive has disappeared.
The last related commit is this one:
commit 02aeec7bde
Date: Tue Apr 27 21:01:30 2010 +0000
Check library name rather than member name when rereading symbols.
Though this just makes the code to stat the archive unconditional, the
code in question existed before this commit.
However, the above commit doesn't include any tests, and seems to
indicate that the problem being addressed was seen on Darwin. I'm not
sure how to setup a test where GDB is using an objfile from within an
archive, and so there's no tests for this commit...
... but if someone can let me know how I can setup a suitable test,
please let me know and I'll try to get something working.
Approved-By: Tom Tromey <tom@tromey.com>
Some gdb.base/fileio.exp tests expect the inferior to not have write
access to some files. If the test is being run as root, this is never
possible. This commit adds a way to identify if the user is root and
xfails the tests that expect no write access.
Approved-By: Tom de Vries <tdevries@suse.de>
Reusing the SME tests, this patch introduces additional tests to exercise
reading/writing ZT0, availability of the register set, signal context reading
for ZT0 and also core file generation.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
This patch adds support for ZT register dumps/reads for core files. The
ZT register is available when the SME2 feature is advertised as available
by the Linux Kernel.
Unlike the enablement for SME1 and the ZA register, support for SME2 is rather
simple given the fixed size of the ZT0 register.
Validated on the Fast Models.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Teach gdb about the ZT state on signal frames and how to restore
the contents of the registers.
There is a new ZT_MAGIC context that the Linux Kernel uses to communicate
the ZT register state to gdb.
As mentioned before, the ZT state should only be available when the ZA state
is available.
Validated under Fast Models.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
SME2 defines a new 512-bit register named ZT0, and it is only available
if SME is also supported. The ZT0 state is valid only if the SVCR ZA bit
is enabled. Otherwise its contents are empty (0).
The target description is dynamic and gets generated at runtime based on the
availability of the feature.
Validated under Fast Models.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Provide documentation for the SME feature and other information that
should be useful for users that need to debug a SME-capable target.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Add 5 SVE/SME tests to exercise all the new features like reading/writing
registers, pseudo-registers, signal frames and core files.
- Sanity check for SME: Gives a brief smoke test to make sure the most basic
of features are working correctly.
- ZA unavailability tests: Validates the behavior/content of the ZA register
is correct when no payload is available. It also exercises changing the
vector lengths.
- ZA availability tests: These tests exercise reading/writing to all the
possible ZA pseudo-registers, and validates the state is correct.
- Core file tests: Validates that core file reading and writing works
correctly and that all state dumped/loaded is sane. This is exercised for
both Linux Kernel core files and gcore core files.
- Signal frame tests: Validates the correct restoration of SME/SVE/FPSIMD
values across signal frames.
Since some of these tests are very lengthy and take a little while to run
(under QEMU at the moment), I decided to parallelize them into smaller
chunks so we can throw some more CPU power at them so they run faster.
I'd still like to add a few more tests to give the testsuite more coverage
in the areas of SME/SVE. Hopefully in the near future that will happen.
Just a reminder that these SME tests are currently unsupported when gdb is
connected to a remote target. That's because the RSP doesn't support
communicating changes in vector lenghts mid-execution, so gdb will always
get wrong state from the remote target.
Co-Authored-By: Ezra Sitorus <ezra.sitorus@arm.com>
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
This patch enables dumping SME state via gdb's gcore command and also
enables gdb to read SME state from a core file generated by the Linux
Kernel.
Regression-tested on aarch64-linux Ubuntu 22.04/20.04.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Due to the nature of the AArch64 SVE/SME extensions in GDB, each thread
can potentially have distinct target descriptions/gdbarches.
When loading a gcore-generated core file, at the moment GDB gives priority
to the target description dumped to NT_GDB_TDESC. Though technically correct
for most targets, it doesn't work correctly for AArch64 with SVE or SME
support.
The correct approach for AArch64/Linux is to either have per-thread target
description notes in the corefiles or to rely on the
gdbarch_core_read_description hook, so it can figure out the proper target
description for a given thread based on the various available register notes.
The former, although more correct, doesn't address the case of existing gdb's
that only output a single target description note.
This patch goes for the latter, and adds a new gdbarch hook to conditionalize
the use of the corefile target description note. The hook is called
use_target_description_from_corefile_notes.
The hook defaults to returning true, meaning targets will use the corefile
target description note. AArch64 Linux overrides the hook to return false
when it detects any of the SVE or SME register notes in the corefile.
Otherwise it should be fine for AArch64 Linux to use the corefile target
description note.
When we support per-thread target description notes, then we can augment
the AArch64 Linux hook to rely on those notes.
Regression-tested on aarch64-linux Ubuntu 22.04/20.04.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
When we have a core file generated by gdb (via the gcore command), gdb dumps
the target description to a note. During loading of that core file, gdb will
first try to load that saved target description.
This works fine for almost all architectures. But AArch64 has a few
dynamically-generated target descriptions/gdbarch depending on the vector
length that was in use at the time the core file was generated.
The target description gdb dumps to the core file note is the one generated
at the time of attachment/startup. If, for example, the SVE vector length
changed during execution, this would not reflect on the core file, as gdb
would still dump the initial target description.
Another issue is that the gdbarch potentially doesn't match the thread's
real gdbarch, and so things like the register cache may have different formats
and sizes.
To address this, fetch the thread's architecture before dumping its register
state. That way we will always use the correct target description/gdbarch.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Approved-By: Tom Tromey <tom@tromey.com>
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
This struct type seems to have been used in the past as a callback
parameter. Now it seems that case is no longer true, so we can simplify
things by passing the individual parameters linux_core_thread_data
encapsulates directly to the functions.
This is just a cleanup before the next change.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
The Linux Kernel defines a separate context for the TPIDR2 register in a
signal frame. Handle this additional context in gdb so this register
gets restored properly when unwinding through signal frames.
The TPIDR2 register is closely related to SME, and is available when SME
support is reported.
This is tested by testcases that are available in a later patch in the series.
Regressions-tested on aarch64-linux Ubuntu 22.04/20.04.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
With SME, where you have two different vector lengths (vl and svl), it may be
the case that the current frame has a set of vector lengths (A) but the signal
context has a distinct set of vector lengths (B).
In this case, we may run into a situation where GDB attempts to use a gdbarch
created for set A, but it is really dealing with a frame that was using set
B.
This is problematic, specially with SME, because now we have a different
number of pseudo-registers and types that gets cached on creation of each
gdbarch variation.
For AArch64 we really need to be able to use the correct gdbarch for each
frame, and I noticed the signal frame (tramp-frame) doesn't have a settable
prev_arch field. So it ends up using the default frame_unwind_arch function
and eventually calling get_frame_arch (next_frame). That means the previous
frame will always have the same gdbarch as the current frame.
This patch first refactors the AArch64/Linux signal context code, simplifying
it and making it reusable for our purposes of calculating the previous frame's
gdbarch.
I introduced a struct that holds information that we have found in the signal
context, and with which we can make various decisions.
Finally, a small change to tramp-frame.c and tramp-frame.h to expose a
prev_arch hook that the architecture can set.
With this new field, AArch64/Linux can implement a hook that looks at the
signal context and infers the gdbarch for the previous frame.
Regression-tested on aarch64-linux Ubuntu 22.04/20.04.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Teach gdb about the ZA/SSVE state on signal frames and how to restore
the contents of the registers.
There is a new ZA_MAGIC context that the Linux Kernel uses to communicate
the ZA register state to gdb.
The SVE_MAGIC context has also been adjusted to contain a flag indicating
whether it is a SVE or SSVE state.
Regression-tested on aarch64-linux Ubuntu 22.04/20.04.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
While doing some SME work, I ran into the situation where the Z register
contents restored from a signal frame are incorrect if the signal frame
only contains fpsimd state and no sve state.
This happens because we only restore the v register values in that case,
and don't do anything for the z registers.
Fix this by initializing the z registers to 0 and then copying over the
overlapping part of the v registers to the z registers.
While at it, refactor the code a bit to simplify it and make it smaller.
Regression-tested on aarch64-linux Ubuntu 22.04/20.04.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
The SME (Scalable Matrix Extension) [1] exposes a new matrix register ZA with
variable sizes. It also exposes a new mode called streaming mode.
Similarly to SVE, the ZA register size is dictated by a vector length, but the
SME vector length is called streaming vetor length. The total size for
ZA in a given moment is svl x svl.
In streaming mode, the SVE registers have their sizes based on svl rather than
the regular vector length (vl).
The feature detection is controlled by the HWCAP2_SME bit, but actual support
should be validated by attempting a ptrace call for one of the new register
sets: NT_ARM_ZA and NT_ARM_SSVE.
Due to its large size, the ZA register is exposed as a vector of bytes, but we
introduce a number of pseudo-registers that gives various different views
into the ZA contents. These can be arranged in a couple categories: tiles and
tile slices.
Tiles are matrices the same size or smaller than ZA. Tile slices are vectors
which map to ZA's rows/columns in different ways.
A new dynamic target description is provided containing the ZA register, the SVG
register and the SVCR register. The size of ZA, like the SVE vector registers,
is based on the vector length register SVG (VG for SVE).
This patch enables SME register support for gdb.
[1] https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/scalable-matrix-extension-armv9-a-architecture
Co-Authored-By: Ezra Sitorus <ezra.sitorus@arm.com>
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
In a target without SVE support, the V registers have a size of 16 bytes,
otherwise they may have a size bigger than 16 bytes (depending on the current
vector length for the Z registers, as they overlap the V registers).
In aarch64-tdep.c:aarch64_store_return_value, the code is laid
out in a way that allocates the buffer with the size of the register, but
only updates the amount of bytes for the particular type we're returning.
This may cause a situation where we have a register size of 32 bytes but
are returning a floating point value of 8 bytes. The temporary buffer
will therefore have 32 bytes, but we'll only update 8 bytes of it.
When we write the entire register back, it will have potentially 24 bytes
of garbage in it.
Fix this by first reading the original contents of the register and then
overriding only the bytes that we need for the return value.
Tested on aarch64-linux Ubuntu 22.04/20.04.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
This is a patch in preparation to upcoming patches enabling SME support. It
attempts to simplify the gdb/gdbserver shared interface used to read/write
SVE registers.
Where the current code makes use of unique_ptr, allocating a new buffer by
hand and passing a buffer around, this patch makes that code use
gdb::byte_vector and passes a reference to this byte vector to the functions,
allowing the functions to have ready access to the size of the buffer.
It also shares a bit more code between gdb and gdbserver, in particular around
handling of ptrace get/set requests for SVE.
I think gdbserver could be refactored to handle register reads/writes more
like gdb's native layer as opposed to letting the generic linux-low layer do
the ptrace calls. This is not very flexible and assumes one size for the
responses. If you have something like NT_ARM_SVE, where you can have either
FPSIMD or SVE contents, it doesn't work that well.
I didn't want to change that interface right now as it is a bit too much work
and touches all the targets, some of which I can't easily test.
Hence the reason why the buffer the generic linux-now passes down to
linux-aarch64-low is unused or ignored.
No user-visible changes should happen as part of this refactor other than a
slightly reworded warning message.
While doing the refactor, I also noticed what seems to be a mistake in checking
if the register cache contains active (non-zero) SVE data.
For instance, the original code did something like this in
aarch64_sve_regs_copy_from_reg_buf:
has_sve_state |= reg_buf->raw_compare (AARCH64_SVE_Z0_REGNUM + i
reg, sizeof (__int128_t));
"reg" is a zeroed-out buffer that we compare the Z register contents
past the first 128 bits. The problem here is that raw_compare returns
1 if the contents compare the same, which means has_sve_state will be
true. But if we compared the Z register contents to 0, it means we
*do not* have SVE state, and therefore has_sve_state should be false.
The consequence of this mistake is that we convert the initial
FPSIMD-formatted data we get from ptrace for the NT_ARM_SVE register
set to a SVE-formatted one.
In the end, this doesn't cause user-visible differences because the
values of both the Z and V registers will still be the same. But the
logic is not correct.
I used the opportunity to fix this, and it gets tested later on by
the additional SME tests.
I do plan on submitting some SVE-specific tests to make sure we have
a bit more coverage in GDB's testsuite.
Regression-tested on aarch64-linux Ubuntu 22.04/20.04.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
In preparation to the SME support patches, rename the SVE-specific files to
something a bit more meaningful that can be shared with the SME code.
In this case, I've renamed the "sve" in the names to "scalable".
No functional changes.
Regression-tested on aarch64-linux Ubuntu 22.04/20.04.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
I noticed we don't handle register reads/writes in the best way for native
AArch64 Linux. Some other registers are fetched/stored even if upper level
code told us to fetch a particular register number.
Fix this by being more strict about which registers we touch when
reading/writing them in the native AArch64 Linux layer.
There should be no user-visible changes due to this patch.
Regression-tested on aarch64-linux Ubuntu 22.04/20.04.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
When creating a core file from within GDB we include a NT_GDB_TDESC
that includes the target description of the architecture in use.
For architectures with dynamic architectures (e.g. AArch64 with
sve/sme) the original architecture, calculated from the original
target description, might not match the per-thread architecture.
In the general case, where each thread has a different architecture,
then we really need a separate NT_GDB_TDESC for each thread, however,
there's currently no way to read in multiple NT_GDB_TDESC.
This commit is a step towards per-thread NT_GDB_TDESC. In this commit
I have updated the function that writes the NT_GDB_TDESC to accept a
gdbarch (rather than calling target_gdbarch() to find a gdbarch), and
I now pass in the gdbarch of the signalled thread.
In many cases (though NOT all) targets with dynamic architectures
really only use a single architecture, even when there are multiple
threads, so in the common case, this should ensure that GDB emits an
architecture that is more likely to be correct.
Additional work will be needed in order to support corefiles with
truly per-thread architectures, but that will need to be done in the
future.
Reformat a Python file with black after this commit:
commit 59912fb2d2
Date: Tue Sep 19 11:45:36 2023 +0100
gdb: add Python events for program space addition and removal
There should be no functional change with this commit.
Yesterday I pushed a patch to fix a small oversight in the DAP code
that caused an instructionReference to be an array instead of a
string.
This patch adds a test case for that regression. This required
exposing the TON form of the response -- something I mentioned might
be necessary when this code was changed to return just the Tcl form.
I tested this by backing out yesterday's bug fix and verifying that a
failure is seen.
Following on Tom de Vries' work in the other array-printers, this
patch changes val_print_packed_array_elements to also avoid allocating
too many values when printing an Ada packed array.
I see this failure:
FAIL: gdb.base/jit-reader-simple.exp: standalone: change addr: initial run: maint info breakpoints shows jit breakpoint
The jit breakpoint expected by the test is there, it's just that the
number of spaces doesn't match what the test expects, after "jit
events":
-2 jit events keep y 0x0000555555555119 <__jit_debug_register_code> inf 1
Fix that by relaxing the regex a bit.
Change-Id: Ia3b04e6d5978399d940fd1a590f95f15275ca7ac
This setting controls whether GDB may attempt to download ELF/DWARF
sections from debuginfod servers.
This setting is enabled by default if gdb is built with debuginfod
section download support (requires libdebuginfod 0.188).
Also update debuginfod command help text and gdb.texinfo with
information on section downloading and the new command.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Andrew Burgess <aburgess@redhat.com>
Add new function debuginfod_section_query. This function queries
debuginfod servers for an individual ELF/DWARF section associated with
a given build-id.
Approved-By: Andrew Burgess <aburgess@redhat.com>
When running test-case gdb.ada/import.exp with gcc 7, most test fail:
...
FAIL: gdb.ada/import.exp: print imported_var_ada
FAIL: gdb.ada/import.exp: print local_imported_var
FAIL: gdb.ada/import.exp: print pkg.imported_var_ada
FAIL: gdb.ada/import.exp: print pkg.exported_var_ada
FAIL: gdb.ada/import.exp: print exported_var_ada
FAIL: gdb.ada/import.exp: gdb_breakpoint: set breakpoint at pkg.imported_func_ada
FAIL: gdb.ada/import.exp: gdb_breakpoint: set breakpoint at imported_func_ada
FAIL: gdb.ada/import.exp: gdb_breakpoint: set breakpoint at local_imported_func
...
When running with gcc 8 or 9, only 2 tests fail:
...
FAIL: gdb.ada/import.exp: gdb_breakpoint: set breakpoint at pkg.imported_func_ada
FAIL: gdb.ada/import.exp: gdb_breakpoint: set breakpoint at imported_func_ada
...
The test-case passes fully with gcc 10, 11, 12 and 13.
Debug info for pragma import seems to not have been supported before gcc 8, so
require that version.
The two FAILs with gcc 8 and 9 seem to be due to problems in debug info. Add
an xfail for these.
Tested on x86_64-linux.
Approved-By: Tom Tromey <tom@tromey.com>
With gcc 13.2.1, I run into a cluster of fails:
...
FAIL: gdb.ada/str_binop_equal.exp: print my_str = "ABCD"
FAIL: gdb.ada/widewide.exp: print my_wws = " helo"
FAIL: gdb.ada/widewide.exp: print my_ws = "wide"
...
The problem is that the debug info contains information about function
ada.strings.maps."=", and gdb uses it to implement the comparison.
The function is supposed to compare two char sets, not strings, so gdb
shouldn't use it. This is PR ada/30908.
I don't see the same problem with gcc 7.5.0, because the exec doesn't contain
the debug info for the function, because the corresponding object is not
linked in. Adter adding "with Ada.Strings.Maps; use Ada.Strings.Maps;" to
gdb.ada/widewide/foo.adb I run into the same problem with gcc 7.5.0.
Add KFAILs for the PR.
Tested on x86_64-linux:
- openSUSE Leap 15.4 (using gcc 7.5.0), and
- openSUSE Tumbleweed (using gcc 13.2.1).
Approved-By: Tom Tromey <tom@tromey.com>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30908
Initially I just wanted a Python event for when GDB removes a program
space, I'm writing a Python extension that caches information for each
program space, and need to know when I should discard entries for a
particular program space.
But, it seemed easy enough to also add an event for when GDB adds a
new program space, so I went ahead and added both new events.
Of course, we don't currently have an observable for program space
addition or removal, so I first needed to add these. After that it's
pretty simple to add two new Python events and have these trigger.
The two new event registries are:
events.new_progspace
events.free_progspace
These emit NewProgspaceEvent and FreeProgspaceEvent objects
respectively, each of these new event types has a 'progspace'
attribute that contains the relevant gdb.Progspace object.
There's a couple of things to be mindful of.
First, it is not possible to catch the NewProgspaceEvent for the very
first program space, the one that is created when GDB first starts, as
this program space is created before any Python scripts are sourced.
In order to allow this event to be caught we would need to defer
creating the first program space, and as a consequence the first
inferior, until some later time. But, existing scripts could easily
depend on there being an initial inferior, so I really don't think we
should change that -- and so, we end up with the consequence that we
can't catch the event for the first program space.
The second, I think minor, issue, is that GDB doesn't clean up its
program spaces upon exit -- or at least, they are not cleaned up
before Python is shut down. As a result, any program spaces in use at
the time GDB exits don't generate a FreeProgspaceEvent. I'm not
particularly worried about this for my use case, I'm using the event
to ensure that a cache doesn't hold stale entries within a single GDB
session. It's also easy enough to add a Python at-exit callback which
can do any final cleanup if needed.
Finally, when testing, I did hit a slightly weird issue with some of
the remote boards (e.g. remote-stdio-gdbserver). As a consequence of
this issue I see some output like this in the gdb.log:
(gdb) PASS: gdb.python/py-progspace-events.exp: inferior 1
step
FreeProgspaceEvent: <gdb.Progspace object at 0x7fb7e1d19c10>
warning: cannot close "target:/lib64/libm.so.6": Cannot execute this command while the target is running.
Use the "interrupt" command to stop the target
and then try again.
warning: cannot close "target:/lib64/libc.so.6": Cannot execute this command while the target is running.
Use the "interrupt" command to stop the target
and then try again.
warning: cannot close "target:/lib64/ld-linux-x86-64.so.2": Cannot execute this command while the target is running.
Use the "interrupt" command to stop the target
and then try again.
do_parent_stuff () at py-progspace-events.c:41
41 ++global_var;
(gdb) PASS: gdb.python/py-progspace-events.exp: step
The 'FreeProgspaceEvent ...' line is expected, that's my test Python
extension logging the event. What isn't expected are all the blocks
like:
warning: cannot close "target:/lib64/libm.so.6": Cannot execute this command while the target is running.
Use the "interrupt" command to stop the target
and then try again.
It turns out that this has nothing to do with my changes, this is just
a consequence of reading files over the remote protocol. The test
forks a child process which GDB stays attached too. When the child
exits, GDB cleans up by calling prune_inferiors, which in turn can
result in GDB trying to close some files that are open because of the
inferior being deleted.
If the prune_inferiors call occurs when the remote target is
running (and in non-async mode) then GDB will try to send a fileio
packet while the remote target is waiting for a stop reply, and the
remote target will throw an error, see remote_target::putpkt_binary in
remote.c for details.
I'm going to look at fixing this, but, as I said, this is nothing to
do with this change, I just mention it because I ended up needing to
account for these warning messages in one of my tests, and it all
looks a bit weird.
Approved-By: Tom Tromey <tom@tromey.com>
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
This backlink is not necessary, we always know the program space from
the context. Pass it down the solib_unloaded observer.
Change-Id: I45a503472dc791f517558b8141901472634e0556
Approved-By: Tom Tromey <tom@tromey.com>
I ran across this site:
https://no-color.org/
... which lobbies for tools to recognize the NO_COLOR environment
variable and disable any terminal styling when it is seen.
This patch implements this for gdb.
Regression tested on x86-64 Fedora 38.
Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
Reviewed-by: Kevin Buettner <kevinb@redhat.com>
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Andrew Burgess <aburgess@redhat.com>
At one time, circa 2006, there was a bug, which was presumably fixed
without adding a test case:
If you provided some relative path to the shared library, such as
with
export LD_LIBRARY_PATH=.
then gdb would fail to match the shared library name during the
TLS lookup.
I think there may have been a bit more to it than is provided by that
explanation, since the test also takes care to split the debug info
into a separate file.
In any case, this commit is based on one of Red Hat's really old
local patches. I've attempted to update it and remove a fair amount
of cruft, hopefully without losing any critical elements from the
test.
Testing on Fedora 38 (correctly) shows 1 unsupported test for
native-gdbserver and 5 PASSes for the native target as well as
native-extended-gdbserver.
In his review of v1 of this patch, Lancelot SIX observed that
'thread_local' could be used in place of '__thread' in the C source
files. But it only became available via the standard in C11, so I
used additional_flags=-std=c11 for compiling both the shared object
and the main program.
Also, while testing with CC_FOR_TARGET=clang, I found that
'additional_flags=-Wl,-soname=${binsharedbase}' caused clang
to complain that this linker flag was unused when compiling
the source file, so I moved this linker option to 'ldflags='.
My testing for this v2 patch shows the same results as with v1,
but I've done additional testing with CC_FOR_TARGET=clang as
well. The results are the same as when gcc is used.
Co-Authored-by: Jan Kratochvil <jan@jankratochvil.net>
Reviewed-By: Lancelot Six <lancelot.six@amd.com>
I'm starting to work on these files, I thought it would be a good time
to remove unused imports. These were identified by
include-what-you-use. Tested by rebuilding.
Change-Id: I3eaf3fa0ea3506c7ecfbc8ecff5031433b1dadb8
Reviewed-By: John Baldwin <jhb@FreeBSD.org>
PR29040 describes a FAIL for test-case gdb.threads/next-fork-other-thread.exp
and target board unix/-m32.
The FAIL happens due to the test executable running into an assert, which is
caused by a forked child segfaulting, like so:
...
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x00000000 in ?? ()
...
I tried to reproduce the segfault with exec next-fork-other-thread-fork, using
TUI layout asm.
I set a breakpoint at fork and ran to the breakpoint, and somewhere during the
following session I ran into a gdb segfault here in
tui_find_disassembly_address:
...
/* Disassemble forward. */
next_addr = tui_disassemble (gdbarch, asm_lines, new_low, max_lines);
last_addr = asm_lines.back ().addr;
...
due to asm_lines being empty after the call to tui_disassemble, while
asm_lines.back () assumes that it's not empty.
I have not been able to reproduce that segfault in that original setting, I'm
not sure of the exact scenario (though looking back it probably involved
"set detach-on-fork off").
What likely happened is that I managed to reproduce PR29040, and TUI (attempted
to) display the disassembly for address 0, which led to the gdb segfault.
When gdb_print_insn encounters an insn it cannot print because it can't read
the memory, it throws a MEMORY_ERROR that is caught by tui_disassemble.
The specific bit that causes the gdb segfault is that if gdb_print_insn throws
a MEMORY_ERROR for the first insn in tui_disassemble, it returns an empty
asm_lines.
FWIW, I did manage to reproduce the gdb segfault as follows:
...
$ gdb -q \
-iex "set pagination off" \
/usr/bin/rustc \
-ex "set breakpoint pending on" \
-ex "b dl_main" \
-ex run \
-ex "up 4" \
-ex "layout asm" \
-ex "print \$pc"
...
<TUI>
...
$1 = (void (*)()) 0x1
(gdb)
...
Now press <up>, and the segfault triggers.
Fix the segfault by handling asm_lines.empty () results of tui_disassemble in
tui_find_disassembly_address.
I've written a unit test that exercises this scenario.
Tested on x86_64-linux.
Reviewed-by: Kevin Buettner <kevinb@redhat.com>
PR tui/30823
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30823
This removes the old gdb_bfd_openr_iovec entirely. I think any new
code should use the type-safe approach.
Reviewed-By: Lancelot Six <lancelot.six@amd.com>
This converts the solib-rocm BFD iovec implementations to the new
type-safe gdb_bfd_openr_iovec. They were already essentially using
this approach, just without the type-safe wrapper.
Thanks to Lancelot Six for testing and fixing this patch.
Co-Authored-By: Lancelot Six <lancelot.six@amd.com>
Acked-by: Lancelot Six <lancelot.six@amd.com>
Reviewed-By: Lancelot Six <lancelot.six@amd.com>
This converts the target fileio BFD iovec implementation to use the
new type-safe gdb_bfd_openr_iovec.
Reviewed-By: Lancelot Six <lancelot.six@amd.com>
This patch adds a new, type-safe variant of gdb_bfd_openr_iovec. In
this approach, the underlying user data is simply an object, the
callbacks are methods, and the "open" function is a function view.
Nothing uses this new code yet.
Reviewed-By: Lancelot Six <lancelot.six@amd.com>
This commit fixes an issue that was discovered while writing the tests
for the previous commit.
I noticed that, when GDB restarts an inferior, the executable_changed
event would trigger twice. The first notification would originate
from:
#0 exec_file_attach (filename=0x4046680 "/tmp/hello.x", from_tty=0) at ../../src/gdb/exec.c:513
#1 0x00000000006f3adb in reopen_exec_file () at ../../src/gdb/corefile.c:122
#2 0x0000000000e6a3f2 in generic_mourn_inferior () at ../../src/gdb/target.c:3682
#3 0x0000000000995121 in inf_child_target::mourn_inferior (this=0x2fe95c0 <the_amd64_linux_nat_target>) at ../../src/gdb/inf-child.c:192
#4 0x0000000000995cff in inf_ptrace_target::mourn_inferior (this=0x2fe95c0 <the_amd64_linux_nat_target>) at ../../src/gdb/inf-ptrace.c:125
#5 0x0000000000a32472 in linux_nat_target::mourn_inferior (this=0x2fe95c0 <the_amd64_linux_nat_target>) at ../../src/gdb/linux-nat.c:3609
#6 0x0000000000e68a40 in target_mourn_inferior (ptid=...) at ../../src/gdb/target.c:2761
#7 0x0000000000a323ec in linux_nat_target::kill (this=0x2fe95c0 <the_amd64_linux_nat_target>) at ../../src/gdb/linux-nat.c:3593
#8 0x0000000000e64d1c in target_kill () at ../../src/gdb/target.c:924
#9 0x00000000009a19bc in kill_if_already_running (from_tty=1) at ../../src/gdb/infcmd.c:328
#10 0x00000000009a1a6f in run_command_1 (args=0x0, from_tty=1, run_how=RUN_STOP_AT_MAIN) at ../../src/gdb/infcmd.c:381
#11 0x00000000009a20a5 in start_command (args=0x0, from_tty=1) at ../../src/gdb/infcmd.c:527
#12 0x000000000068dc5d in do_simple_func (args=0x0, from_tty=1, c=0x35c7200) at ../../src/gdb/cli/cli-decode.c:95
While the second originates from:
#0 exec_file_attach (filename=0x3d7a1d0 "/tmp/hello.x", from_tty=0) at ../../src/gdb/exec.c:513
#1 0x0000000000dfe525 in reread_symbols (from_tty=1) at ../../src/gdb/symfile.c:2517
#2 0x00000000009a1a98 in run_command_1 (args=0x0, from_tty=1, run_how=RUN_STOP_AT_MAIN) at ../../src/gdb/infcmd.c:398
#3 0x00000000009a20a5 in start_command (args=0x0, from_tty=1) at ../../src/gdb/infcmd.c:527
#4 0x000000000068dc5d in do_simple_func (args=0x0, from_tty=1, c=0x35c7200) at ../../src/gdb/cli/cli-decode.c:95
In the first case the call to exec_file_attach first passes through
reopen_exec_file. The reopen_exec_file performs a modification time
check on the executable file, and only calls exec_file_attach if the
executable has changed on disk since it was last loaded.
However, in the second case things work a little differently. In this
case GDB is really trying to reread the debug symbol. As such, we
iterate over the objfiles list, and for each of those we check the
modification time, if the file on disk has changed then we reload the
debug symbols from that file.
However, there is an additional check, if the objfile has the same
name as the executable then we will call exec_file_attach, but we do
so without checking the cached modification time that indicates when
the executable was last reloaded, as a result, we reload the
executable twice.
In this commit I propose that reread_symbols be changed to
unconditionally call reopen_exec_file before performing the objfile
iteration. This will ensure that, if the executable has changed, then
the executable will be reloaded, however, if the executable has
already been recently reloaded, we will not reload it for a second
time.
After handling the executable, GDB can then iterate over the objfiles
list and reload them in the normal way.
With this done I now see the executable reloaded only once when GDB
restarts an inferior, which means I can remove the kfail that I added
to the gdb.python/py-exec-file.exp test in the previous commit.
Approved-By: Tom Tromey <tom@tromey.com>
This commit makes the executable_changed observable available through
the Python API as an event. There's nothing particularly interesting
going on here, it just follows the same pattern as many of the other
Python events we support.
The new event registry is called events.executable_changed, and this
emits an ExecutableChangedEvent object which has two attributes, a
gdb.Progspace called 'progspace', this is the program space in which
the executable changed, and a Boolean called 'reload', which is True
if the same executable changed on disk and has been reloaded, or is
False when a new executable has been loaded.
One interesting thing did come up during testing though, you'll notice
the test contains a setup_kfail call. During testing I observed that
the executable_changed event would trigger twice when GDB restarted an
inferior. However, the ExecutableChangedEvent object is identical for
both calls, so the wrong information is never sent out, we just see
one too many events.
I tracked this down to how the reload_symbols function (symfile.c)
takes care to also reload the executable, however, I've split fixing
this into a separate commit, so see the next commit for details.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>
