The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the testsuite
library files (in boards/, config/, and lib/). Previous commits have
removed all uses of the 'then' keyword from the test script files,
this commit just cleans up the library files.
There should be no changes in what is tested after this commit.
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the remaining
gdb.*/*.exp scripts. Previous commits have done the bulk of this
removal, this commit just handles the remaining directories that each
contain a low number of instances.
There should be no changes in what is tested after this commit.
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.multi/
test script directory.
There should be no changes in what is tested after this commit.
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.fortran/
test script directory.
There should be no changes in what is tested after this commit.
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.disasm/
test script directory.
There should be no changes in what is tested after this commit.
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.reverse/
test script directory.
There should be no changes in what is tested after this commit.
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.trace/
test script directory.
There should be no changes in what is tested after this commit.
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.threads/
test script directory.
There should be no changes in what is tested after this commit.
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.python/
test script directory.
There should be no changes in what is tested after this commit.
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.cp/
test script directory.
There should be no changes in what is tested after this commit.
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.arch/
test script directory.
There should be no changes in what is tested after this commit.
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.base/
test script directory.
There should be no changes in what is tested after this commit.
The canonical form of 'if' in modern TCL is 'if {} {}'. But there's
still a bunch of places in the testsuite where we make use of the
'then' keyword, and sometimes these get copies into new tests, which
just spreads poor practice.
This commit removes all use of the 'then' keyword from the gdb.ada/
test script directory.
There should be no changes in what is tested after this commit.
The gdb.fortran/nested-funcs.exp test script has DOS line endings. I
can see no reason why this script needs DOS line endings.
Convert to UNIX line endings.
There should be no change in what is tested after this commit.
When using the "set logging" commands, cli_interp_base::set_logging
will send gdb_stdlog output (among others) to the tee it makes for
gdb_stdout. However, this has the side effect of also causing logging
to use the pager. This is PR gdb/29787.
This patch fixes the problem by keeping stderr and stdlog separate
from stdout, preserving the rule that only gdb_stdout should page.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29787
Right now, tee_file owns the second stream it writes to. This is done
for the convenience of the users. In a subsequent patch, this will no
longer be convenient, so this patch moves the responsibility for
ownership to the users of tee_file.
CLI redirect uses a global variable, 'saved_output'. However, globals
are generally bad, and there is no need for this one -- it can be a
member of cli_interp_base. This patch makes this change.
Older gcc versions (here 4.9.2) can't handle auto for a lambda parameter:
../../gdb/windows-nat.c: In member function 'void windows_nat_target::delete_thread(ptid_t, DWORD, bool)':
../../gdb/windows-nat.c:629:12: error: use of 'auto' in lambda parameter declaration only available with -std=c++1y or -std=gnu++1y [-Werror]
[=] (auto &th)
^
For i686 the CreateThread entry point function needs the WINAPI (stdcall)
calling convention:
../../gdb/windows-nat.c: In constructor 'windows_nat_target::windows_nat_target()':
../../gdb/windows-nat.c:450:56: error: invalid user-defined conversion from 'windows_nat_target::windows_nat_target()::<lambda(LPVOID)>' to 'LPTHREAD_START_ROUTINE' {aka 'long unsigned int (__attribute__((stdcall)) *)(void*)'} [-fpermissive]
450 | HANDLE bg_thread = CreateThread (nullptr, 64 * 1024, fn, this, 0, nullptr);
| ^~
../../gdb/windows-nat.c:444:13: note: candidate is: 'constexpr windows_nat_target::windows_nat_target()::<lambda(LPVOID)>::operator DWORD (*)(LPVOID)() const' (near match)
444 | auto fn = [] (LPVOID self) -> DWORD
| ^
../../gdb/windows-nat.c:444:13: note: no known conversion from 'DWORD (*)(LPVOID)' {aka 'long unsigned int (*)(void*)'} to 'LPTHREAD_START_ROUTINE' {aka 'long unsigned int (__attribute__((stdcall)) *)(void*)'}
Since it's not possible to change the calling convention of a lambda, I've
moved it to a separate function.
In disasm.h we define a set of types that are used by the various
disassembler classes to hold callback functions before passing the
callbacks into libopcodes.
Because libopcodes is C code, and on some (many?) targets, C code is
compiled without exception support, it is important that GDB not try
to throw an exception over libopcode code.
In the previous commit all the existing callbacks were marked as
noexcept, however, this doesn't protect us from a future change to GDB
either adding a new callback that is not noexcept, or removing the
noexcept keyword from an existing callback.
In this commit I mark all the callback types as noexcept. This means
that GDB's disassembler classes will no longer compile if we try to
pass a callback that is not marked as noexcept.
At least, that's the idea. Unfortunately, it's not that easy.
Before C++17, the noexcept keyword on a function typedef would be
ignored, thus:
using func_type = void (*) (void) noexcept;
void
a_func ()
{
throw 123;
}
void
some_func (func_type f)
{
f ();
}
int
main ()
{
some_func (a_func);
return 0;
}
Will compile just fine for C++11 and C++14 with GCC. Clang on the
other hand complains that 'noexcept' should not appear on function
types, but then does appear to correctly complain that passing a_func
is a mismatch in the set of exceptions that could be thrown.
Switching to C++17 and both GCC and Clang correctly point out that
passing a_func is an invalid conversion relating to the noexcept
keyword. Changing a_func to:
void
a_func () noexcept
{ /* Nothing. */ }
And for C++17 both GCC and Clang compile this just fine.
My conclusion then is that adding the noexcept keyword to the function
types is pointless while GDB is not compiled as C++17, and silencing
the warnings would require us to jump through a bunch of hoops.
And so, in this commit, I define a macro LIBOPCODE_CALLBACK_NOEXCEPT,
this macro expands to noexcept when compiling for C++17, but otherwise
expands to nothing. I then add this macro to the function types.
I've compiled GDB as the default C++11 and also forced the compile to
C++17. When compiling as C++17 I spotted a few additional places
where callbacks needed to be marked noexcept (these fixes were merged
into the previous commit, but this confirmed to be that the macro is
working as expected).
While working on another patch, Simon pointed out that GDB could be
improved by marking the functions passed to the disassembler as
noexcept.
https://sourceware.org/pipermail/gdb-patches/2022-October/193084.html
The reason this is important is the on some hosts, libopcodes, being C
code, will not be compiled with support for handling exceptions. As
such, an attempt to throw an exception over libopcodes code will cause
GDB to terminate.
See bug gdb/29712 for an example of when this happened.
In this commit all the functions that are passed to the disassembler,
and which might be used as callbacks by libopcodes are marked
noexcept.
Ideally, I would have liked to change these typedefs:
using read_memory_ftype = decltype (disassemble_info::read_memory_func);
using memory_error_ftype = decltype (disassemble_info::memory_error_func);
using print_address_ftype = decltype (disassemble_info::print_address_func);
using fprintf_ftype = decltype (disassemble_info::fprintf_func);
using fprintf_styled_ftype = decltype (disassemble_info::fprintf_styled_func);
which are declared in disasm.h, as including the noexcept keyword.
However, when I tried this, I ran into this warning/error:
In file included from ../../src/gdb/disasm.c:25:
../../src/gdb/disasm.h: In constructor ‘gdb_printing_disassembler::gdb_printing_disassembler(gdbarch*, ui_file*, gdb_disassemble_info::read_memory_ftype, gdb_disassemble_info::memory_error_ftype, gdb_disassemble_info::print_address_ftype)’:
../../src/gdb/disasm.h:116:3: error: mangled name for ‘gdb_printing_disassembler::gdb_printing_disassembler(gdbarch*, ui_file*, gdb_disassemble_info::read_memory_ftype, gdb_disassemble_info::memory_error_ftype, gdb_disassemble_info::print_address_ftype)’ will change in C++17 because the exception specification is part of a function type [-Werror=noexcept-type]
116 | gdb_printing_disassembler (struct gdbarch *gdbarch,
| ^~~~~~~~~~~~~~~~~~~~~~~~~
So I've left that change out. This does mean that if somebody adds a
new use of the disassembler classes in the future, and forgets to mark
the callbacks as noexcept, this will compile fine. We'll just have to
manually check for that during review.
Bug gdb/29712 identifies a problem with the Python disassembler API.
In some cases GDB will try to throw an exception through the
libopcodes disassembler code, however, not all targets include
exception unwind information when compiling C code, for targets that
don't include this information GDB will terminate when trying to pass
the exception through libopcodes.
To explain what GDB is trying to do, consider the following trivial
use of the Python disassembler API:
class ExampleDisassembler(gdb.disassembler.Disassembler):
class MyInfo(gdb.disassembler.DisassembleInfo):
def __init__(self, info):
super().__init__(info)
def read_memory(self, length, offset):
return super().read_memory(length, offset)
def __init__(self):
super().__init__("ExampleDisassembler")
def __call__(self, info):
info = self.MyInfo(info)
return gdb.disassembler.builtin_disassemble(info)
This disassembler doesn't add any value, it defers back to GDB to do
all the actual work, but it serves to allow us to discuss the problem.
The problem occurs when a Python exception is raised by the
MyInfo.read_memory method. The MyInfo.read_memory method is called
from the C++ function gdbpy_disassembler::read_memory_func. The C++
stack at the point this function is called looks like this:
#0 gdbpy_disassembler::read_memory_func (memaddr=4198805, buff=0x7fff9ab9d2a8 "\220ӹ\232\377\177", len=1, info=0x7fff9ab9d558) at ../../src/gdb/python/py-disasm.c:510
#1 0x000000000104ba06 in fetch_data (info=0x7fff9ab9d558, addr=0x7fff9ab9d2a9 "ӹ\232\377\177") at ../../src/opcodes/i386-dis.c:305
#2 0x000000000104badb in ckprefix (ins=0x7fff9ab9d100) at ../../src/opcodes/i386-dis.c:8571
#3 0x000000000104e28e in print_insn (pc=4198805, info=0x7fff9ab9d558, intel_syntax=-1) at ../../src/opcodes/i386-dis.c:9548
#4 0x000000000104f4d4 in print_insn_i386 (pc=4198805, info=0x7fff9ab9d558) at ../../src/opcodes/i386-dis.c:9949
#5 0x00000000004fa7ea in default_print_insn (memaddr=4198805, info=0x7fff9ab9d558) at ../../src/gdb/arch-utils.c:1033
#6 0x000000000094fe5e in i386_print_insn (pc=4198805, info=0x7fff9ab9d558) at ../../src/gdb/i386-tdep.c:4072
#7 0x0000000000503d49 in gdbarch_print_insn (gdbarch=0x5335560, vma=4198805, info=0x7fff9ab9d558) at ../../src/gdb/gdbarch.c:3351
#8 0x0000000000bcc8c6 in disasmpy_builtin_disassemble (self=0x7f2ab07f54d0, args=0x7f2ab0789790, kw=0x0) at ../../src/gdb/python/py-disasm.c:324
### ... snip lots of frames as we pass through Python itself ...
#22 0x0000000000bcd860 in gdbpy_print_insn (gdbarch=0x5335560, memaddr=0x401195, info=0x7fff9ab9e3c8) at ../../src/gdb/python/py-disasm.c:783
#23 0x00000000008995a5 in ext_lang_print_insn (gdbarch=0x5335560, address=0x401195, info=0x7fff9ab9e3c8) at ../../src/gdb/extension.c:939
#24 0x0000000000741aaa in gdb_print_insn_1 (gdbarch=0x5335560, vma=0x401195, info=0x7fff9ab9e3c8) at ../../src/gdb/disasm.c:1078
#25 0x0000000000741bab in gdb_disassembler::print_insn (this=0x7fff9ab9e3c0, memaddr=0x401195, branch_delay_insns=0x0) at ../../src/gdb/disasm.c:1101
So gdbpy_disassembler::read_memory_func is called from the libopcodes
disassembler to read memory, this C++ function then calls into user
supplied Python code to do the work.
If the user supplied Python code raises an gdb.MemoryError exception
indicating the memory read failed, this is fine. The C++ code
converts this exception back into a return value that libopcodes can
understand, and returns to libopcodes.
However, if the user supplied Python code raises some other exception,
what we want is for this exception to propagate through GDB and appear
as if raised by the call to gdb.disassembler.builtin_disassemble. To
achieve this, when gdbpy_disassembler::read_memory_func spots an
unknown Python exception, we must pass the information about this
exception from frame #0 to frame #8 in the above backtrace. Frame #8
is the C++ implementation of gdb.disassembler.builtin_disassemble, and
so it is this function that we want to re-raise the unknown Python
exception, so the user can, if they want, catch the exception in their
code.
The previous mechanism by which the exception was passed was to pack
the details of the Python exception into a C++ exception, then throw
the exception from frame #0, and catch the exception in frame #8,
unpack the details of the Python exception, and re-raise it.
However, this relies on the exception passing through frames #1 to #7,
some of which are in libopcodes, which is C code, and so, might not be
compiled with exception support.
This commit proposes an alternative solution that does not rely on
throwing a C++ exception.
When we spot an unhandled Python exception in frame #0, we will store
the details of this exception within the gdbpy_disassembler object
currently in use. Then we return to libopcodes a value indicating
that the memory_read failed.
libopcodes will now continue to disassemble as though that memory read
failed (with one special case described below), then, when we
eventually return to disasmpy_builtin_disassemble we check to see if
there is an exception stored in the gdbpy_disassembler object. If
there is then this exception can immediately be installed, and then we
return back to Python, when the user will be able to catch the
exception.
There is one extra change in gdbpy_disassembler::read_memory_func.
After the first call that results in an exception being stored on the
gdbpy_disassembler object, any future calls to the ::read_memory_func
function will immediately return as if the read failed. This avoids
any additional calls into user supplied Python code.
My thinking here is that should the first call fail with some unknown
error, GDB should not keep trying with any additional calls. This
maintains the illusion that the exception raised from
MyInfo.read_memory is immediately raised by
gdb.disassembler.builtin_disassemble. I have no tests for this change
though - to trigger this issue would rely on a libopcodes disassembler
that will try to read further memory even after the first failed
read. I'm not aware of any such disassembler that currently does
this, but that doesn't mean such a disassembler couldn't exist in the
future.
With this change in place the gdb.python/py-disasm.exp test should now
pass on AArch64.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29712
Approved-By: Simon Marchi <simon.marchi@efficios.com>
I noticed that execution_control_state has a 'reset' method, and
there's also a 'reset_ecs' function that calls it. This patch cleans
this area up a little by adding a parameter to the constructor and (a
change Simon suggested) removing the reset method. Some extraneous
variables are also removed, like:
- struct execution_control_state ecss;
- struct execution_control_state *ecs = &ecss;
Here 'ecs' is never changed, so this patch removes it entirely in
favor of just using the object everywhere.
Regression tested on x86-64 Fedora 34.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
From glibc 2.35 and later, the "map_failed" stap probe is no longer
included in glibc. The removal of the probe looks like an accident,
but it was caused by a glibc commit which meant that the "map_failed"
probe could no longer be reached; the compiler then helpfully
optimised out the probe.
In GDB, in solib-svr4.c, we have a list of probes that we look for
related to the shared library loading detection. If any of these
probes are missing then GDB will fall back to the non-probe based
mechanism for detecting shared library loading. The "map_failed"
probe is include in the list of required probes.
This means that on glibc 2.35 (or later) systems, GDB is going to
always fall back to the non-probes based mechanism for detecting
shared library loading.
I raised a glibc bug to discuss this issue:
https://sourceware.org/bugzilla/show_bug.cgi?id=29818
But, whatever the ultimate decision from the glibc team, given there
are version of glibc in the wild without the "map_failed" probe, we
probably should update GDB to handle this situation.
The "map_failed" probe is already a little strange, very early
versions of glibc didn't include this probe, so, in some cases, if
this probe is missing GDB is happy to ignore it. This is fine, the
action associated with this probe inside GDB is DO_NOTHING, this means
the probe isn't actually required in order for GDB to correctly detect
the loading of shared libraries.
In this commit I propose changing the rules so that any probe whose
action is DO_NOTHING, is optional.
There is one possible downside to this change, and that concerns 'set
stop-on-solib-events on'. If a probe is removed from glibc, but the
old style breakpoint based mechanism is still in place within glibc
for that same event, then GDB will stop when using the old style
non-probe based mechanism, but not when using the probes based
mechanism.
For the map_failed case this is not a problem, both the map_failed
probe, and the call to the old style breakpoint location were
optimised out, and so neither event (probes based, or breakpoint
based) will trigger. This would only become an issue if glibc removed
a probe, but left the breakpoint in place (this would almost certainly
be a bug in glibc).
For now, I'm proposing that we just don't worry about this. Because
some probes have actions that are not DO_NOTHING, then we know the
user will always seem _some_ stops when a shared library is
loaded/unloaded, and (I'm guessing), in most cases, that's all they
care about. I figure when someone complains then we can figure out
what the right solution is then.
With this commit in place, then, when using a glibc 2.35 or later
system, GDB will once again use the stap probes for shared library
detection.
Reviewed-By: Lancelot SIX <lancelot.six@amd.com>
On powerpc64le-linux I run into:
...
(gdb) PASS: gdb.ada/task_watch.exp: info tasks before inserting breakpoint
watch -location value task 3^M
Watchpoint 2: -location value^M
(gdb) PASS: gdb.ada/task_watch.exp: watch -location value task 3
continue^M
Continuing.^M
[Thread 0x7ffff7ccf170 (LWP 65550) exited]^M
[Thread 0x7ffff7abf170 (LWP 65551) exited]^M
FAIL: gdb.ada/task_watch.exp: continue to watchpoint (timeout)
...
On x86_64-linux (where the test-case passes), a hardware watchpoint is used:
...
(gdb) PASS: gdb.ada/task_watch.exp: info tasks before inserting breakpoint
watch -location value task 3^M
Hardware watchpoint 2: -location value^M
...
and after forcing "set can-use-hw-watchpoints 0" we can intermittently
reproduce the same failure.
In the gdb documentation related to watchpoints in multi-threaded programs, we
read:
...
Warning: In multi-threaded programs, software watchpoints have only limited
usefulness. If GDB creates a software watchpoint, it can only watch the value
of an expression in a single thread. If you are confident that the expression
can only change due to the current thread’s activity (and if you are also
confident that no other thread can become current), then you can use software
watchpoints as usual. However, GDB may not notice when a non-current thread’s
activity changes the expression. (Hardware watchpoints, in contrast, watch an
expression in all threads.)
...
Since the ada task construct is mapped onto threads, it seems that the
same limitation holds for tasks.
Fix this by using skip_hw_watchpoint_tests.
Tested on powerpc64-linux.
Tested-By: Carl Love <cel@us.ibm.com>
On powerpc64le-linux, with test-case gdb.ada/out_of_line_in_inlined.exp I run
into:
...
(gdb) run ^M
Starting program: foo_o224_021-all ^M
^M
Breakpoint 1, 0x0000000010002f48 in foo_o224_021.child1.child2 (s=...) at \
foo_o224_021.adb:24^M
24 function Child2 (S : String) return Boolean is -- STOP^M
(gdb) FAIL: gdb.ada/out_of_line_in_inlined.exp: scenario=all: \
run to foo_o224_021.child1.child2
...
The breakpoint is correctly set at the local entry point, and given that the
local entry point doesn't correspond to a line number entry, the instruction
address of the breakpoint is shown.
The problem is that test-case doesn't expect the breakpoint address.
Fix this by allowing the breakpoint address to occur.
Tested on powerpc64le-linux.
there's no reason why the tree-based variant can't always be used
when sorting is required, it merely needs to also support filename
sorting and have a fast path for insertion at end (aka rightmost tree
leaf).
The filename sorting isn't tested anywhere and the only scripttempl
that uses it is avr (for 'SORT(*)(.ctors)'), and I believe even there it
was a mistake. Either way, this adds a testcase for filename sorting as
well.
Then the non-BST based sorting can be simplified to only support
the fast case of no sorting required at all (at the same time renaming
the two variants to _sort and _nosort).
fnmatch is slow, so avoiding it in more cases is good. This implements
a more generic version of match_simple_wild which needs some
pre-processing of patterns. In particular it supports patterns of the
form PREFIX*SUFFIX (where all parts are optional), i.e. a super set of
what's handled now. Most section matchers of this form and hence don't
need any calls to fnmatch anymore.
We retain the implementation of match_simple_wild for the filename
matchers (they aren't called often enough to matter).
I broke gdb.ada/start.exp, and did not notice it, because it outputs an
UNTESTED if gdb_start_cmd fails. I don't really see when start would
fail and it's not a problem that should be looked at. Change all spots
that call untested after a gdb_start_cmd failure, use fail instead.
Doing so caused some failures with the native-gdbserver board. Some
tests that use "start" were relying on the fact that start would fail
with that board to just return with "untested". Change them to add an
early return if use_gdb_stub returns true.
Some gdb.pascal tests also failed with native-gdbserver, because they
did use gdb_start_cmd to start the inferior, for no good reason.
Convert them to use runto_main instead, which does the right thing if
the target is a stub.
A further refactoring could be to make gdb_start_cmd match the expected
breakpoint hit and the prompt, which it doesn't do currently (it leaves
that to the callers, but not all of them do).
Change-Id: I097370851213e798ff29fb6cf8ba25ef7d2be007
Reviewed-By: Bruno Larsen <blarsen@redhat.com>
Approved-By: Andrew Burgess <aburgess@redhat.com>
The code to create a range type has a heuristic to decide whether the
range is unsigned. However, this heuristic can fail if the upper
bound of the range has its high bit set, because the test is done
using LONGEST.
With this patch, if the underlying type of a range is unsigned, then
the range will always be unsigned. A new test is included.
Regression tested on x86-64 Fedora 34. We've also been using this
internally at AdaCore for a while.
New in this version:
- Better comment in target_kill
- Uncomment line in test to avoid hanging when exiting, when testing on
native-extended-gdbserver
PR 28275 shows that doing a sequence of:
- Run inferior in background (run &)
- kill that inferior
- Run again
We get into this assertion:
/home/smarchi/src/binutils-gdb/gdb/target.c:2590: internal-error: target_wait: Assertion `!proc_target->commit_resumed_state' failed.
#0 internal_error_loc (file=0x5606b344e740 "/home/smarchi/src/binutils-gdb/gdb/target.c", line=2590, fmt=0x5606b344d6a0 "%s: Assertion `%s' failed.") at /home/smarchi/src/binutils-gdb/gdbsupport/errors.cc:54
#1 0x00005606b6296475 in target_wait (ptid=..., status=0x7fffb9390630, options=...) at /home/smarchi/src/binutils-gdb/gdb/target.c:2590
#2 0x00005606b5767a98 in startup_inferior (proc_target=0x5606bfccb2a0 <the_amd64_linux_nat_target>, pid=3884857, ntraps=1, last_waitstatus=0x0, last_ptid=0x0) at /home/smarchi/src/binutils-gdb/gdb/nat/fork-inferior.c:482
#3 0x00005606b4e6c9c5 in gdb_startup_inferior (pid=3884857, num_traps=1) at /home/smarchi/src/binutils-gdb/gdb/fork-child.c:132
#4 0x00005606b50f14a5 in inf_ptrace_target::create_inferior (this=0x5606bfccb2a0 <the_amd64_linux_nat_target>, exec_file=0x604000039f50 "/home/smarchi/build/binutils-gdb/gdb/test", allargs="", env=0x61500000a580, from_tty=1)
at /home/smarchi/src/binutils-gdb/gdb/inf-ptrace.c:105
#5 0x00005606b53b6d23 in linux_nat_target::create_inferior (this=0x5606bfccb2a0 <the_amd64_linux_nat_target>, exec_file=0x604000039f50 "/home/smarchi/build/binutils-gdb/gdb/test", allargs="", env=0x61500000a580, from_tty=1)
at /home/smarchi/src/binutils-gdb/gdb/linux-nat.c:978
#6 0x00005606b512b79b in run_command_1 (args=0x0, from_tty=1, run_how=RUN_NORMAL) at /home/smarchi/src/binutils-gdb/gdb/infcmd.c:468
#7 0x00005606b512c236 in run_command (args=0x0, from_tty=1) at /home/smarchi/src/binutils-gdb/gdb/infcmd.c:526
When running the kill command, commit_resumed_state for the
process_stratum_target (linux-nat, here) is true. After the kill, when
there are no more threads, commit_resumed_state is still true, as
nothing touches this flag during the kill operation. During the
subsequent run command, run_command_1 does:
scoped_disable_commit_resumed disable_commit_resumed ("running");
We would think that this would clear the commit_resumed_state flag of
our native target, but that's not the case, because
scoped_disable_commit_resumed iterates on non-exited inferiors in order
to find active process targets. And after the kill, the inferior is
exited, and the native target was unpushed from it anyway. So
scoped_disable_commit_resumed doesn't touch the commit_resumed_state
flag of the native target, it stays true. When reaching target_wait, in
startup_inferior (to consume the initial expect stop events while the
inferior is starting up and working its way through the shell),
commit_resumed_state is true, breaking the contract saying that
commit_resumed_state is always false when calling the targets' wait
method.
(note: to be correct, I think that startup_inferior should toggle
commit_resumed between the target_wait and target_resume calls, but I'll
ignore that for now)
I can see multiple ways to fix this. In the end, we need
commit_resumed_state to be cleared by the time we get to that
target_wait. It could be done at the end of the kill command, or at the
beginning of the run command.
To keep things in a coherent state, I'd like to make it so that after
the kill command, when the target is left with no threads, its
commit_resumed_state flag is left to false. This way, we can keep
working with the assumption that a target with no threads (and therefore
no running threads) has commit_resumed_state == false.
Do this by adding a scoped_disable_commit_resumed in target_kill. It
clears the target's commit_resumed_state on entry, and leaves it false
if the target does not have any resumed thread on exit. That means,
even if the target has another inferior with stopped threads,
commit_resumed_state will be left to false, which makes sense.
Add a test that tries to cover various combinations of actions done
while an inferior is running (and therefore while commit_resumed_state
is true on the process target).
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28275
Change-Id: I8e6fe6dc1f475055921520e58cab68024039a1e9
Approved-By: Andrew Burgess <aburgess@redhat.com>
New in this version: add a dedicated test.
When I do this:
$ ./gdb -nx --data-directory=data-directory -q \
/bin/sleep \
-ex "maint set target-non-stop on" \
-ex "tar ext :1234" \
-ex "set remote exec-file /bin/sleep" \
-ex "run 1231 &" \
-ex add-inferior \
-ex "inferior 2"
Reading symbols from /bin/sleep...
(No debugging symbols found in /bin/sleep)
Remote debugging using :1234
Starting program: /bin/sleep 1231
Reading /lib64/ld-linux-x86-64.so.2 from remote target...
warning: File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead.
Reading /lib64/ld-linux-x86-64.so.2 from remote target...
Reading /usr/lib/debug/.build-id/a6/7a1408f18db3576757eea210d07ba3fc560dff.debug from remote target...
[New inferior 2]
Added inferior 2 on connection 1 (extended-remote :1234)
[Switching to inferior 2 [<null>] (<noexec>)]
(gdb) Reading /lib/x86_64-linux-gnu/libc.so.6 from remote target...
attach 3659848
Attaching to process 3659848
/home/smarchi/src/binutils-gdb/gdb/thread.c:85: internal-error: inferior_thread: Assertion `current_thread_ != nullptr' failed.
Note the "attach" command just above. When doing it on the command-line
with a -ex switch, the bug doesn't trigger.
The internal error of GDB is actually caused by GDBserver crashing, and
the error recovery of GDB is not on point. This patch aims to fix just
the GDBserver crash, not the GDB problem.
GDBserver crashes with a segfault here:
(gdb) bt
#0 0x00005555557fb3f4 in find_one_thread (ptid=...) at /home/smarchi/src/binutils-gdb/gdbserver/thread-db.cc:177
#1 0x00005555557fd5cf in thread_db_thread_handle (ptid=<error reading variable: Cannot access memory at address 0xffffffffffffffa0>, handle=0x7fffffffc400, handle_len=0x7fffffffc3f0)
at /home/smarchi/src/binutils-gdb/gdbserver/thread-db.cc:461
#2 0x000055555578a0b6 in linux_process_target::thread_handle (this=0x5555558a64c0 <the_x86_target>, ptid=<error reading variable: Cannot access memory at address 0xffffffffffffffa0>, handle=0x7fffffffc400,
handle_len=0x7fffffffc3f0) at /home/smarchi/src/binutils-gdb/gdbserver/linux-low.cc:6905
#3 0x00005555556dfcc6 in handle_qxfer_threads_worker (thread=0x60b000000510, buffer=0x7fffffffc8a0) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:1645
#4 0x00005555556e00e6 in operator() (__closure=0x7fffffffc5e0, thread=0x60b000000510) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:1696
#5 0x00005555556f54be in for_each_thread<handle_qxfer_threads_proper(buffer*)::<lambda(thread_info*)> >(struct {...}) (func=...) at /home/smarchi/src/binutils-gdb/gdbserver/gdbthread.h:159
#6 0x00005555556e0242 in handle_qxfer_threads_proper (buffer=0x7fffffffc8a0) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:1694
#7 0x00005555556e04ba in handle_qxfer_threads (annex=0x629000000213 "", readbuf=0x621000019100 '\276' <repeats 200 times>..., writebuf=0x0, offset=0, len=4097)
at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:1732
#8 0x00005555556e1989 in handle_qxfer (own_buf=0x629000000200 "qXfer:threads", packet_len=26, new_packet_len_p=0x7fffffffd630) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:2045
#9 0x00005555556e720a in handle_query (own_buf=0x629000000200 "qXfer:threads", packet_len=26, new_packet_len_p=0x7fffffffd630) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:2685
#10 0x00005555556f1a01 in process_serial_event () at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:4176
#11 0x00005555556f4457 in handle_serial_event (err=0, client_data=0x0) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:4514
#12 0x0000555555820f56 in handle_file_event (file_ptr=0x607000000250, ready_mask=1) at /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:573
#13 0x0000555555821895 in gdb_wait_for_event (block=1) at /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:694
#14 0x000055555581f533 in gdb_do_one_event (mstimeout=-1) at /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:264
#15 0x00005555556ec9fb in start_event_loop () at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:3512
#16 0x00005555556f0769 in captured_main (argc=4, argv=0x7fffffffe0d8) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:3992
#17 0x00005555556f0e3f in main (argc=4, argv=0x7fffffffe0d8) at /home/smarchi/src/binutils-gdb/gdbserver/server.cc:4078
The reason is a wrong current process when find_one_thread is called.
The current process is the 2nd one, which was just attached. It does
not yet have thread_db data (proc->priv->thread_db is nullptr). As we
iterate on all threads of all process to fulfull the qxfer:threads:read
request, we get to a thread of process 1 for which we haven't read
thread_db information yet (lwp_info::thread_known is false), so we get
into find_one_thread. find_one_thread uses
`current_process ()->priv->thread_db`, assuming the current process
matches the ptid passed as a parameter, which is wrong. A segfault
happens when trying to dereference that thread_db pointer.
Fix this by making find_one_thread not assume what the current process /
current thread is. If it needs to call into libthread_db, which we know
will try to read memory from the current process, then temporarily set
the current process.
In the case where the thread is already know and we return early, we
don't need to switch process.
Add a test to reproduce this specific situation.
Change-Id: I09b00883e8b73b7e5f89d0f47cb4e9c0f3d6caaa
Approved-By: Andrew Burgess <aburgess@redhat.com>
PR cli/29800 points out that "document" will now crash when the
argument is an undefined command. This is a regression due to the
"document user-defined aliases" patch.
Approved-By: Joel Brobecker <brobecker@adacore.com>
Reviewed-By: Philippe Waroquiers <philippe.waroquiers@skynet.be>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29800
On powerpc64le-linux, I run into:
...
(gdb) PASS: gdb.opt/solib-intra-step.exp: first-hit
step^M
28 { /* first-retry */^M
(gdb) FAIL: gdb.opt/solib-intra-step.exp: second-hit
...
It's a bit easier to understand what happens if we do a full stepping session:
...
Temporary breakpoint 1, main ()
at solib-intra-step-main.c:23
23 shlib_first ();
(gdb) step
shlib_first () at solib-intra-step-lib.c:29
29 shlib_second (0); /* first-hit */
(gdb) step
28 { /* first-retry */
(gdb) step
29 shlib_second (0); /* first-hit */
(gdb) step
shlib_second (dummy=0)
at solib-intra-step-lib.c:23
23 abort (); /* second-hit */
...
and compare that to the line info:
...
CU: solib-intra-step-lib.c:
File name Line number Starting address View Stmt
solib-intra-step-lib.c 22 0x710 x
solib-intra-step-lib.c 23 0x724 x
solib-intra-step-lib.c 28 0x740 x
solib-intra-step-lib.c 29 0x74c x
solib-intra-step-lib.c 28 0x750 x
solib-intra-step-lib.c 29 0x758 x
solib-intra-step-lib.c 30 0x760 x
solib-intra-step-lib.c - 0x77c
...
So we step from line 29 to line 28, and back to line 29, which is behaviour
that matches the line table. The peculiar order is due to using optimization.
The problem is that the test-case doesn't expect this order.
Fix this by allowing this order in the test-case.
Tested on powerpc64le-linux.
PR testsuite/29792
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29792
This commit addresses one of the issues identified in PR gdb/28275.
Bug gdb/28275 identifies a number of situations in which this assert:
Assertion `!proc_target->commit_resumed_state' failed.
could be triggered. There's actually a number of similar places where
this assert is found in GDB, the two of interest in gdb/28275 are in
target_wait and target_stop.
In one of the comments:
https://sourceware.org/bugzilla/show_bug.cgi?id=28275#c1
steps to trigger the assertion within target_stop were identified when
using a modified version of the gdb.threads/detach-step-over.exp test
script.
In the gdb.threads/detach-step-over.exp test, we attach to a
multi-threaded inferior, and continue the inferior in asynchronous
(background) mode. Each thread is continuously hitting a conditional
breakpoint where the condition is always false. While the inferior is
running we detach. The goal is that we detach while GDB is performing a
step-over for the conditional breakpoint in at least one thread.
While detaching, if a step-over is in progress, then GDB has to
complete the step over before we can detach. This involves calling
target_stop and target_wait (see prepare_for_detach).
As far as gdb/28275 is concerned, the interesting part here, is the
the process_stratum_target::commit_resumed_state variable must be
false when target_stop and target_wait are called.
This is currently ensured because, in detach_command (infrun.c), we
create an instance of scoped_disable_commit_resumed, this ensures that
when target_detach is called, ::commit_resumed_state will be false.
The modification to the test that I propose here, and which exposed
the bug, is that, instead of using "detach" to detach from the
inferior, we instead use "quit". Quitting GDB after attaching to an
inferior will cause GDB to first detach, and then exit.
When we quit GDB we end up calling target_detach via a different code
path, the stack looks like:
#0 target_detach
#1 kill_or_detach
#2 quit_force
#3 quit_command
Along this path there is no scoped_disable_commit_resumed created.
::commit_resumed_state can be true when we reach prepare_for_detach,
which calls target_wait and target_stop, so the assertion will trigger.
In this commit, I propose fixing this by adding the creation of a
scoped_disable_commit_resumed into target_detach. This will ensure
that ::commit_resumed_state is false when calling prepare_for_detach
from within target_detach.
I did consider placing the scoped_disable_commit_resumed in
prepare_for_detach, however, placing it in target_detach ensures that
the target's commit_resumed_state flag is left to false if the detached
inferior was the last one for that target. It's the same rationale as
for patch "gdb: disable commit resumed in target_kill" that comes later
in this series, but for detach instead of kill.
detach_command still includes a scoped_disable_commit_resumed too, but I
think it is still relevant to cover the resumption at the end of the
function.
Co-Authored-By: Simon Marchi <simon.marchi@efficios.com>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28275
Change-Id: Ie128f7aba6ef0e018859275eca372e6ea738e96f
Factor out some bits of gdb.threads/detach-step-over.exp to procs in
preparation to adding some new variations of the test. Rename the
existing "test" proc and make it use proc_with_prefix.
Co-Authored-By: Simon Marchi <simon.marchi@efficios.com>
Change-Id: Ib4412545c81c8556029e0f7bfa9dd48d7a9f3189
Before doing further changes to this file, change to use the :: notation
instead of declaring global variables with the `global` keyword.
Change-Id: I72301fd8f4693fea61aac054ba17245a1f4442fb
Approved-By: Andrew Burgess <aburgess@redhat.com>
On powerpc64le-linux, using gcc 4.8.5, I run into:
...
(gdb) PASS: gdb.arch/altivec-regs.exp: next (1)
next^M
11 c = vec_add (a, b);^M
(gdb) PASS: gdb.arch/altivec-regs.exp: next (2)
print/x a^M
$67 = {0xfefefefe, 0xfefefefe, 0xfefefefe, 0xfefefefe}^M
(gdb) FAIL: gdb.arch/altivec-regs.exp: print vector parameter a
...
Looking at the disassembly and the debug info, it's clear why there's
a FAIL.
The debug info says that the variable can be found at some stack location, but
the instructions don't seem to be writing there.
We can work around this by marking variable a volatile. Likewise for b.
Note that marking the variables as volatile doesn't change the location
information.
Tested on power64le-linux.
With test-case gdb.base/msym-bp-shl.exp on powerpc64le-linux, I run into:
...
(gdb) PASS: gdb.base/msym-bp-shl.exp: debug=0: before run: break foo
info breakpoint^M
Num Type Disp Enb Address What^M
1 breakpoint keep y <MULTIPLE> ^M
1.1 y 0x00000000000008d4 <foo+12>^M
1.2 y 0x0000000000000a34 crti.S:88^M
(gdb) FAIL: gdb.base/msym-bp-shl.exp: debug=0: before run: info breakpoint
...
The problem is that the prologue skipper walks from foo@plt at 0xa28 to 0xa34:
...
0000000000000a28 <foo@plt>:
a28: c0 ff ff 4b b 9e8 <__glink_PLTresolve>
Disassembly of section .fini:
0000000000000a2c <_fini>:
a2c: 02 00 4c 3c addis r2,r12,2
a30: d4 74 42 38 addi r2,r2,29908
a34: a6 02 08 7c mflr r0
...
This is caused by ppc_elfv2_elf_make_msymbol_special which marks foo@plt as
having a local entry point, due to incorrectly accessing an asymbol struct
using a (larger) elf_symbol_type.
Fix this by simply ignoring artificial symbols in
ppc_elfv2_elf_make_msymbol_special.
Tested on powerpc64le.
Approved-By: Ulrich Weigand <uweigand@de.ibm.com>
Reviewed-By: Carl Love <cel@us.ibm.com>
Tested-By: Carl Love <cel@us.ibm.com>
PR tdep/29814
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29814
* emultempl/msp430.em (add_region_prefix <REGION_EITHER>): Use
bfd_rename_section.
* testsuite/ld-msp430-elf/msp430-tiny-rom.ld: Handle varian data
and bss input sections.
Because riscv_merge_std_ext function did not merge the 'H' extension, linked
executables lacked 'H' extension when multiple objects are merged.
This issue is found while building OpenSBI with 'H' extension (resulting
ELF files did not contain "h1p0" in "Tag_RISCV_arch" even if *all* linked
object files contained it).
This commit adds 'h' to standard_exts variable to merge 'H' extension.
bfd/ChangeLog:
* elfnn-riscv.c (riscv_merge_std_ext): Add 'H' extension merging.
This commit tests both (assembler and disassembler) fixes of "Better support
for long instructions".
gas/ChangeLog:
* testsuite/gas/riscv/insn.s: Add testcases such that big number
handling is required and should be disassembled as long ".byte"
sequence with correct instruction bits.
* testsuite/gas/riscv/insn.d: Likewise.
* testsuite/gas/riscv/insn-na.d: Likewise.
* testsuite/gas/riscv/insn-dwarf.d: Likewise.
Commit bb996692bd ("RISC-V/gas: allow generating up to 176-bit
instructions with .insn") tried to start supporting long instructions but
it was insufficient.
1. It heavily depended on the bignum internals (radix of 2^16),
2. It generates "value conflicts with instruction length" even if a big
number instruction encoding does not exceed its expected length and
3. Because long opcode was handled separately (from struct riscv_cl_insn),
some information like DWARF line number correspondence was missing.
To resolve these problems, this commit:
1. Handles bignum (and its encodings) precisely and
2. Incorporates long opcode handling into regular instruction handling.
This commit will be tested on the separate commit.
gas/ChangeLog:
* config/tc-riscv.c (struct riscv_cl_insn): Add long opcode field.
(create_insn) Clear long opcode marker.
(install_insn) Install longer opcode as well.
(s_riscv_insn) Likewise.
(riscv_ip_hardcode): Make big number handling stricter. Length and
the value conflicts only if the bignum size exceeds the expected
maximum length.
Commit bb996692bd ("RISC-V/gas: allow generating up to 176-bit
instructions with .insn") tried to start supporting long instructions but
it was insufficient.
On the disassembler, correct ".byte" output was limited to the first 64-bits
of an instruction. After that, zeroes are incorrectly printed.
Note that, it only happens on ".byte" output (instruction part) and not on
hexdump (data) part. For example, before this commit, hexdump and ".byte"
produces different values:
Assembly:
.insn 22, 0xfedcba98765432100123456789abcdef55aa33cc607f
objdump output example (before the fix):
10: 607f 33cc 55aa cdef .byte 0x7f, 0x60, 0xcc, 0x33, 0xaa, 0x55, 0xef, 0xcd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
18: 89ab 4567 0123 3210
20: 7654 ba98 fedc
Note that, after 0xcd (after first 64-bits of the target instruction), all
".byte" values are incorrectly printed as zero while hexdump prints correct
instruction bits.
To resolve this, this commit adds "packet" argument to support dumping
instructions longer than 64-bits (to print correct instruction bits on
".byte"). This commit will be tested on the separate commit.
Assembly:
.insn 22, 0xfedcba98765432100123456789abcdef55aa33cc607f
objdump output example (after the fix):
10: 607f 33cc 55aa cdef .byte 0x7f, 0x60, 0xcc, 0x33, 0xaa, 0x55, 0xef, 0xcd, 0xab, 0x89, 0x67, 0x45, 0x23, 0x01, 0x10, 0x32, 0x54, 0x76, 0x98, 0xba, 0xdc, 0xfe
18: 89ab 4567 0123 3210
20: 7654 ba98 fedc
opcodes/ChangeLog:
* riscv-dis.c (riscv_disassemble_insn): Print unknown instruction
using the new argument packet.
(riscv_disassemble_data): Add unused argument packet.
(print_insn_riscv): Pass packet to the disassemble function.
