At least x86-64's x32 sub-mode and RISC-V's 32-bit mode calculate
addends as 64-bit values, but store them in signed 32-bit fields when
generating the file without encountering any earlier error. When the
relocated field is a 64-bit one, the value resulting after processing
the relocation record when linking (or the latest when loading) may
thus be wrong due to the truncation.
With the code change in place, one x32 testcase actually triggers the
new diagnostic. That one case of too large a (negative) addend is being
adjusted alongside the addition of a new testcase to actually trigger
the new error. (Note that due to internal BFD behavior the relocation in
.data doesn't get processed anymore after the errors in .text.)
Note that in principle it is possible to express 64-bit relocations in
ELF32, but this would require .rel relocations, i.e. with the addend
stored in the 64-bit field being relocated. But I guess it would be a
lot of effort for little gain to actually support this.
Macro arguments may be separated by commas or just whitespace. Macro
arguments may also be quoted (where one level of quotes is removed in
the course of determining the values for the respective formal
parameters). Furthermore this quote removal knows _two_ somewhat odd
escaping mechanisms: One, apparently in existence forever, is that a
pair of quotes counts as the escaping of a quote, with the pair being
transformed to a single quote in the course of quote removal. The other
(introduced by c06ae4f232) looks more usual on the surface in that it
deals with \" sequences, but it _retains_ the escaping \. Hence only the
former mechanism is suitable when the value to be used by the macro body
is to contain a quote. Yet this results in ambiguity of what "a""b" is
intended to mean; elsewhere (e.g. for .ascii) it represents two
successive string literals. However, in any event is the above different
from "a" "b": I don't think this can be viewed the same as "a""b" when
processing macro arguments.
Change the scrubber to retain such whitespace, by making the processing
of strings more similar to that of symbols. And indeed this appears to
make sense when taking into account that for quite a while gas has been
supporting quoted symbol names.
Taking a more general view, however, the change doesn't go quite far
enough. There are further cases where significant whitespace is removed
by the scrubber. The new testcase enumerates a few in its ".if 0"
section. I'm afraid the only way that I see to deal with this would be
to significantly simplify the scrubber, such that it wouldn't do much
more than collapse sequences of unquoted whitespace into a single blank.
To be honest problems in this area aren't really surprising when seeing
that there's hardly any checking of .macro use throughout the testsuite
(and in particular in the [relatively] generic tests under all/).
If /proc/sys/kernel/yama/ptrace_scope is 1, when execute the following
command without superuser:
make check-gdb TESTS="gdb.base/jit-elf.exp"
we can see the following messages in gdb/testsuite/gdb.log:
(gdb) attach 1650108
Attaching to program: /home/yangtiezhu/build/gdb/testsuite/outputs/gdb.base/jit-elf/jit-elf-main, process 1650108
ptrace: Operation not permitted.
(gdb) FAIL: gdb.base/jit-elf.exp: attach: one_jit_test-2: break here 1: attach
use gdb_attach to fix the above issue, at the same time, the clean_reattach
proc should return a value to indicate whether it worked, and the callers
should return early as well on failure.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
If /proc/sys/kernel/yama/ptrace_scope is 1, when execute the following
command without superuser:
make check-gdb TESTS="gdb.base/attach-pie-noexec.exp"
we can see the following messages in gdb/testsuite/gdb.log:
(gdb) attach 6500
Attaching to process 6500
ptrace: Operation not permitted.
(gdb) PASS: gdb.base/attach-pie-noexec.exp: attach
It is obviously wrong, the expected result should be UNSUPPORTED in such
a case.
With this patch, we can see "Operation not permitted" in the log info,
and then we can do the following processes to test:
(1) set ptrace_scope as 0
$ echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
$ make check-gdb TESTS="gdb.base/attach-pie-noexec.exp"
(2) use sudo
$ sudo make check-gdb TESTS="gdb.base/attach-pie-noexec.exp"
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
This commit adds new gdb_attach to centralize the failure checking of
"attach" command. Return 0 if attach failed, otherwise return 1.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
As Pedro Alves said, caching procs should not issue pass/fail [1],
this commit removes attach test from can_spawn_for_attach, at the
same time, use "verbose -log" instead of "unsupported" to get a
trace about why a test run doesn't support spawning for attach.
[1] https://sourceware.org/pipermail/gdb-patches/2022-March/186311.html
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
This shares aarch64-nat.c and nat/aarch64-hw-point.c with the Linux
native target. Since FreeBSD writes all of the debug registers in one
ptrace op, use an unordered_set<> to track the "dirty" state for
threads rather than bitmasks of modified registers.
This method can be overridden by architecture-specific targets to
perform additional work when a thread is deleted.
Note that this method is only invoked on systems supporting LWP
events, but the pending use case (aarch64 debug registers) is not
supported on older kernels that do not support LWP events.
This class includes platform-independent target methods for hardware
breakpoints and watchpoints using routines from
nat/aarch64-hw-point.c.
stopped_data_address is not platform-independent since the FAR
register holding the address for a breakpoint hit must be fetched in a
platform-specific manner. However, aarch64_stopped_data_address is
provided as a helper routine which performs platform-independent
validation given the value of the FAR register.
For tracking the per-process debug register mirror state, use an
unordered_map indexed by pid as recently adopted in x86-nat.c rather
than a manual linked-list.
Move non-Linux-specific support for hardware break/watchpoints from
nat/aarch64-linux-hw-point.c to nat/aarch64-hw-point.c. Changes
beyond a simple split of the code are:
- aarch64_linux_region_ok_for_watchpoint and
aarch64_linux_any_set_debug_regs_state renamed to drop linux_ as
they are not platform specific.
- Platforms must implement the aarch64_notify_debug_reg_change
function which is invoked from the platform-independent code when a
debug register changes for a given debug register state. This does
not use the indirection of a 'low' structure as is done for x86.
- The handling for kernel_supports_any_contiguous_range is not
pristine. For non-Linux it is simply defined to true. Some uses of
this could perhaps be implemented as new 'low' routines for the
various places that check it instead?
- Pass down ptid into aarch64_handle_breakpoint and
aarch64_handle_watchpoint rather than using current_lwp_ptid which
is only defined on Linux. In addition, pass the ptid on to
aarch64_notify_debug_reg_change instead of the unused state
argument.
This class implements debug register support common between the i386
and amd64 native targets.
While here, remove #ifdef's for HAVE_PT_GETDBREGS in FreeBSD-specific
code. The ptrace request has been present on FreeBSD x86
architectures since 4.0 (released in March 2000). The last FreeBSD
release without this support is 3.5 released in June 2000.
I found a couple of spots that declare a symtab_and_line but don't
actually use it. I think this probably isn't detected as unused
because it has a constructor.
Add a new function, gdb.format_address, which is a wrapper around
GDB's print_address function.
This method takes an address, and returns a string with the format:
ADDRESS <SYMBOL+OFFSET>
Where, ADDRESS is the original address, formatted as hexadecimal,
SYMBOL is a symbol with an address lower than ADDRESS, and OFFSET is
the offset from SYMBOL to ADDRESS in decimal.
If there's no SYMBOL suitably close to ADDRESS then the
<SYMBOL+OFFSET> part is not included.
This is useful if a user wants to write a Python script that
pretty-prints addresses, the user no longer needs to do manual symbol
lookup, or worry about correctly formatting addresses.
Additionally, there are some settings that effect how GDB picks
SYMBOL, and whether the file name and line number should be included
with the SYMBOL name, the gdb.format_address function ensures that the
users Python script also benefits from these settings.
The gdb.format_address by default selects SYMBOL from the current
inferiors program space, and address is formatted using the
architecture for the current inferior. However, a user can also
explicitly pass a program space and architecture like this:
gdb.format_address(ADDRESS, PROGRAM_SPACE, ARCHITECTURE)
In order to format an address for a different inferior.
Notes on the implementation:
In py-arch.c I extended arch_object_to_gdbarch to add an assertion for
the type of the PyObject being worked on. Prior to this commit all
uses of arch_object_to_gdbarch were guaranteed to pass this function a
gdb.Architecture object, but, with this commit, this might not be the
case.
So, with this commit I've made it a requirement that the PyObject be a
gdb.Architecture, and this is checked with the assert. And in order
that callers from other files can check if they have a
gdb.Architecture object, I've added the new function
gdbpy_is_architecture.
In py-progspace.c I've added two new function, the first
progspace_object_to_program_space, converts a PyObject of type
gdb.Progspace to the associated program_space pointer, and
gdbpy_is_progspace checks if a PyObject is a gdb.Progspace or not.
Add debuginfod support to core_target::build_file_mappings and
locate_exec_from_corefile_build_id to enable the downloading of
missing executables and shared libraries referenced in core files.
Also add debuginfod support to solib_map_sections so that previously
downloaded shared libraries can be retrieved from the local debuginfod
cache.
When core file shared libraries are found locally, verify that their
build-ids match the corresponding build-ids found in the core file.
If there is a mismatch, attempt to query debuginfod for the correct
build and print a warning if unsuccessful:
warning: Build-id of /lib64/libc.so.6 does not match core file.
Also disable debuginfod when gcore invokes gdb. Debuginfo is not
needed for core file generation so debuginfod queries will slow down
gcore unnecessarily.
Since commit aa2d5a422 gdb has been able to read executable and shared
library build-ids within core files.
Expand this functionality so that each core file bfd maintains a map of
soname to build-id for each shared library referenced in the core file.
This feature may be used to verify that gdb has found the correct shared
libraries for core files and to facilitate downloading shared libaries via
debuginfod.
If GDB reports a watchpoint hit, and then the next event is not
TARGET_WAITKIND_STOPPED, but instead some event for which there's a
catchpoint, such that GDB calls bpstat_stop_status, GDB mistakenly
thinks the watchpoint triggered. Vis, using foll-fork.c:
(gdb) awatch v
Hardware access (read/write) watchpoint 2: v
(gdb) catch fork
Catchpoint 3 (fork)
(gdb) c
Continuing.
Hardware access (read/write) watchpoint 2: v
Old value = 0
New value = 5
main () at gdb.base/foll-fork.c:16
16 pid = fork ();
(gdb)
Continuing.
Hardware access (read/write) watchpoint 2: v <<<<
<<<< these lines are spurious
Value = 5 <<<<
Catchpoint 3 (forked process 1712369), arch_fork (ctid=0x7ffff7fa4810) at arch-fork.h:49
49 arch-fork.h: No such file or directory.
(gdb)
The problem is that when we handle the fork event, nothing called
watchpoints_triggered before calling bpstat_stop_status. Thus, each
watchpoint's watchpoint_triggered field was still set to
watch_triggered_yes from the previous (real) watchpoint stop.
watchpoint_triggered is only current called in the handle_signal_stop
path, when handling TARGET_WAITKIND_STOPPED.
This fixes it by adding watchpoint_triggered calls in the other events
paths that call bpstat_stop_status. But instead of adding them
explicitly, it adds a new function bpstat_stop_status_nowatch that
wraps bpstat_stop_status and calls watchpoint_triggered, and then
replaces most calls to bpstat_stop_status with calls to
bpstat_stop_status_nowatch.
This required constifying watchpoints_triggered.
New test included, which fails without the fix.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28621
Change-Id: I282b38c2eee428d25319af3bc842f9feafed461c
The previous prepare_resume_reply change missed updating the 'buf'
reference that overwrites the 'T', so if 'buf' was advanced, we'd
still overwrite the wrong character. This fixes it.
Change-Id: Ia8ce433366b85af4e268c1c49e7b447da3130a4d
While playing with adding a new event kind, I noticed that
prepare_resume_reply TARGET_WAITKIND_FORKED, etc. advance 'buf', so if
we force-disable the T packet, we'd fail the *buf == 'T' assertion.
Fix it by tweaking the assertion to always look at the beginning of
the buffer.
Change-Id: I8c38e32353db115edcde418b3b1e8ba12343c22b
On x86 machines with xmm register, and with recent versions of
systemtap (and gcc?), it can occur that stap probe arguments will be
placed into xmm registers.
I notice this happening on a current Fedora Rawhide install with the
following package versions installed:
$ rpm -q glibc systemtap gcc
glibc-2.35.9000-10.fc37.x86_64
systemtap-4.7~pre16468670g9f253544-1.fc37.x86_64
gcc-12.0.1-0.12.fc37.x86_64
If I check the probe data in libc, I see this:
$ readelf -n /lib64/libc.so.6
...
stapsdt 0x0000004d NT_STAPSDT (SystemTap probe descriptors)
Provider: libc
Name: pthread_start
Location: 0x0000000000090ac3, Base: 0x00000000001c65c4, Semaphore: 0x0000000000000000
Arguments: 8@%xmm1 8@1600(%rbx) 8@1608(%rbx)
stapsdt 0x00000050 NT_STAPSDT (SystemTap probe descriptors)
Provider: libc
Name: pthread_create
Location: 0x00000000000912f1, Base: 0x00000000001c65c4, Semaphore: 0x0000000000000000
Arguments: 8@%xmm1 8@%r13 8@8(%rsp) 8@16(%rsp)
...
Notice that for both of these probes, the first argument is a uint64_t
stored in the xmm1 register.
Unfortunately, if I try to use this probe within GDB, then I can't
view the first argument. Here's an example session:
$ gdb $(which gdb)
(gdb) start
...
(gdb) info probes stap libc pthread_create
...
(gdb) break *0x00007ffff729e2f1 # Use address of probe.
(gdb) continue
...
(gdb) p $_probe_arg0
Invalid cast.
What's going wrong? If I re-run my session, but this time use 'set
debug stap-expression 1', this is what I see:
(gdb) set debug stap-expression 1
(gdb) p $_probe_arg0
Operation: UNOP_CAST
Operation: OP_REGISTER
String: xmm1
Type: uint64_t
Operation: UNOP_CAST
Operation: OP_REGISTER
String: r13
Type: uint64_t
Operation: UNOP_CAST
Operation: UNOP_IND
Operation: UNOP_CAST
Operation: BINOP_ADD
Operation: OP_LONG
Type: long
Constant: 0x0000000000000008
Operation: OP_REGISTER
String: rsp
Type: uint64_t *
Type: uint64_t
Operation: UNOP_CAST
Operation: UNOP_IND
Operation: UNOP_CAST
Operation: BINOP_ADD
Operation: OP_LONG
Type: long
Constant: 0x0000000000000010
Operation: OP_REGISTER
String: rsp
Type: uint64_t *
Type: uint64_t
Invalid cast.
(gdb)
The important bit is this:
Operation: UNOP_CAST
Operation: OP_REGISTER
String: xmm1
Type: uint64_t
Which is where we cast the xmm1 register to uint64_t. And the final
piece of the puzzle is:
(gdb) ptype $xmm1
type = union vec128 {
v8bf16 v8_bfloat16;
v4f v4_float;
v2d v2_double;
v16i8 v16_int8;
v8i16 v8_int16;
v4i32 v4_int32;
v2i64 v2_int64;
uint128_t uint128;
}
So, we are attempting to cast a union type to a scalar type, which is
not supporting in C/C++, and as a consequence GDB's expression
evaluator throws an error when we attempt to do this.
The first approach I considered for solving this problem was to try
and make use of gdbarch_stap_adjust_register. We already have a
gdbarch method (gdbarch_stap_adjust_register) that allows us to tweak
the name of the register that we access. Currently only x86
architectures use this to transform things like ax to eax in some
cases.
I wondered, what if we change gdbarch_stap_adjust_register to do more
than just change the register names? What if this method instead
became gdbarch_stap_read_register. This new method would return a
operation_up, and would take the register name, and the type we are
trying to read from the register, and return the operation that
actually reads the register.
The default implementation of this method would just use
user_reg_map_name_to_regnum, and then create a register_operation,
like we already do in stap_parse_register_operand. But, for x86
architectures this method would fist possibly adjust the register
name, then do the default action to read the register. Finally, for
x86 this method would spot when we were accessing an xmm register,
and, based on the type being pulled from the register, would extract
the correct field from the union.
The benefit of this approach is that it would work with the expression
types that GDB currently supports. The draw back would be that this
approach would not be very generic. We'd need code to handle each
sub-field size with an xmm register. If other architectures started
using vector registers for probe arguments, those architectures would
have to create their own gdbarch_stap_read_register method. And
finally, the type of the xmm registers comes from the type defined in
the target description, there's a risk that GDB might end up
hard-coding the names of type sub-fields, then if a target uses a
different target description, with different field names for xmm
registers, the stap probes would stop working.
And so, based on all the above draw backs, I rejected this first
approach.
My second plan involves adding a new expression type to GDB called
unop_extract_operation. This new expression takes a value and a type,
during evaluation the value contents are fetched, and then a new value
is extracted from the value contents (based on type). This is similar
to the following C expression:
result_value = *((output_type *) &input_value);
Obviously we can't actually build this expression in this case, as the
input_value is in a register, but hopefully the above makes it clearer
what I'm trying to do.
The benefit of the new expression approach is that this code can be
shared across all architectures, and it doesn't care about sub-field
names within the union type.
The draw-backs that I see are potential future problems if arguments
are not stored within the least significant bytes of the register.
However if/when that becomes an issue we can adapt the
gdbarch_stap_read_register approach to allow architectures to control
how a value is extracted.
For testing, I've extended the existing gdb.base/stap-probe.exp test
to include a function that tries to force an argument into an xmm
register. Obviously, that will only work on a x86 target, so I've
guarded the new function with an appropriate GCC define. In the exp
script we use readelf to check if the probe exists, and is using the
xmm register.
If the probe doesn't exist then the associated tests are skipped.
If the probe exists, put isn't using the xmm register (which will
depend on systemtap/gcc versions), then again, the tests are skipped.
Otherwise, we can run the test. I think the cost of running readelf
is pretty low, so I don't feel too bad making all the non-xmm targets
running this step.
I found that on a Fedora 35 install, with these packages installed, I
was able to run this test and have the probe argument be placed in an
xmm register:
$ rpm -q systemtap gcc glibc
systemtap-4.6-4.fc35.x86_64
gcc-11.2.1-9.fc35.x86_64
glibc-2.34-7.fc35.x86_64
Finally, as this patch adds a new operation type, then I need to
consider how to generate an agent expression for the new operation
type.
I have kicked the can down the road a bit on this. In the function
stap_parse_register_operand, I only create a unop_extract_operation in
the case where the register type is non-scalar, this means that in
most cases I don't need to worry about generating an agent expression
at all.
In the xmm register case, when an unop_extract_operation will be
created, I have sketched out how the agent expression could be
handled, however, this code is currently not reached. When we try to
generate the agent expression to place the xmm register on the stack,
GDB hits this error:
(gdb) trace -probe-stap test:xmmreg
Tracepoint 1 at 0x401166
(gdb) actions
Enter actions for tracepoint 1, one per line.
End with a line saying just "end".
>collect $_probe_arg0
Value not scalar: cannot be an rvalue.
This is because GDB doesn't currently support placing non-scalar types
on the agent expression evaluation stack. Solving this is clearly
related to the original problem, but feels a bit like a second
problem. I'd like to get feedback on whether my approach to solving
the original problem is acceptable or not before I start looking at
how to handle xmm registers within agent expressions.
PR 28978
* dwarf2.c (scan_unit_for_symbols): When performing second pass,
check to see if the function or variable being processed is the
same as the previous one.
Unlike in 64-bit mode, where values wrap at the 64-bit boundary anyway,
there's no wrapping at the 32-bit boundary here, and hence overflow
detection shouldn't be suppressed just because rela relocations are
going to be used.
The extra check against NO_RELOC is actually a result of an ilp32 test
otherwise failing. But thinking about it, reporting overflows for
not-really-relocations (typically because of earlier errors) makes
little sense in general. Perhaps this should even be extended to non-
64-bit modes.
The test case added here is testing the bug gdb/28856, where calling a
function by hand from a pretty printer makes GDB crash. There are 6
mechanisms to trigger this crash in the current test, using the commands
backtrace, up, down, finish, step and continue. Since the failure happens
because of use-after-free (more details below) the tests will always
have a chance of passing through sheer luck, but anecdotally they seem
to fail all of the time.
The reason GDB is crashing is a use-after-free problem. The above
mentioned functions save a pointer to the current frame's information,
then calls the pretty printer, and uses the saved pointer for different
reasons, depending on the function. The issue happens because
call_function_by_hand needs to reset the obstack to get the current
frame, invalidating the saved pointer.
In testsuite/README, we suggest that you can run the testsuite against
some other GDB binary by using:
make check RUNTESTFLAGS=GDB=/usr/bin/gdb
However, that example isn't fully correct, because with that command
line, the testsuite will still pass
-data-directory=[pwd]/../data-directory
to /usr/bin/gdb, like e.g.:
...
builtin_spawn /usr/bin/gdb -nw -nx -data-directory /home/pedro/gdb/build/gdb/testsuite/../data-directory -iex set height 0 -iex set width 0
...
while if you're testing an installed GDB (the system GDB being the
most usual scenario), then you should normally let it use its own
configured directory, not the just-built GDB's data directory.
This commit improves the status quo with the following two changes:
- if the user specifies GDB on the command line, then by default,
don't start GDB with the -data-directory command line option.
I.e., let the tested GDB use its own configured data directory.
- let the user override the data directory, via a new
GDB_DATA_DIRECTORY global. This replaces the existing
BUILD_DATA_DIRECTORY variable in testsuite/lib/gdb.exp, which
wasn't overridable, and was a bit misnamed for the new purpose.
So after this, the following commands I believe behave intuitively:
# Test the non-installed GDB in some build dir:
make check \
RUNTESTFLAGS="GDB=/path/to/other/build/gdb \
GDB_DATA_DIRECTORY=/path/to/other/build/gdb/data-directory"
# Test the GDB installed in some prefix:
make check \
RUNTESTFLAGS="GDB=/opt/gdb/bin/gdb"
# Test the built GDB with some alternative data directory, e.g., the
system GDB's data directory:
make check \
RUNTESTFLAGS="GDB_DATA_DIRECTORY=/usr/share/gdb"
Change-Id: Icdc21c85219155d9564a9900961997e6624b78fb
PR 28791
* config/tc-z80.c (emit_data_val): Do not warn about overlarge
constants generated by bit manipulation operators.
* testsuite/gas/z80/pr28791.s: New test source file.
* testsuite/gas/z80/pr28791.d: New test driver file.
The change in read_a_source_file prevents the particular testcase in
the PR from triggering the assertion in demand_empty_rest_of_line.
I've also removed the assertion. Nothing much goes wrong with gas if
something else triggers it, so it's not worthy of an abort.
I've also changed my previous patch to ignore_rest_of_line to allow
that function to increment input_line_pointer past buffer_limit, like
demand_empty_rest_of_line: The two functions ought to behave the
same in that respect. Finally, demand_empty_rest_of_line gets a
little hardening to prevent accesses past buffer_limit plus one.
PR 28979
* read.c (read_a_source_file): Calculate known size for sbuf
rather than calling strlen.
(demand_empty_rest_of_line): Remove "know" check. Expand comment.
Don't dereference input_line_pointer when past buffer_limit.
(ignore_rest_of_line): Allow input_line_pointer to increment to
buffer_limit plus one. Expand comment.
Now that the GDB 12 branch has been created,
this commit bumps the version number in gdb/version.in to
13.0.50.DATE-git
For the record, the GDB 12 branch was created
from commit 2be64de603.
Also, as a result of the version bump, the following changes
have been made in gdb/testsuite:
* gdb.base/default.exp: Change $_gdb_major to 13.
ld/testsuite/ld-loongarch-elf
* ld-loongarch-elf.exp: Test LoongArch32 and LoongArch64 testcases respectively.
* jmp_op.d: Fix bug in test LoongArch32.
* disas-jirl-32.d: New test case for LoongArch32.
* disas-jirl-32.s: New test case for LoongArch32.
* disas-jirl.d: Skip test case LoongArch32.
* macro_op_32.d: New test case for LoongArch32.
* macro_op_32.s: New test case for LoongArch32.
* macro_op.d: Skip test case LoongArch32.
Some test cases about ifunc.
bfd/
* elfnn-loongarch.c
* elfxx-loongarch.h
=== ld Summary ===
of expected passes 1430
of expected failures 11
of untested testcases 1
of unsupported tests 154
