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This commit aims to address a problem that exists with the current
approach to displaced stepping, and was identified in PR gdb/22921.
Displaced stepping is currently supported on AArch64, ARM, amd64,
i386, rs6000 (ppc), and s390. Of these, I believe there is a problem
with the current approach which will impact amd64 and ARM, and can
lead to random register corruption when the inferior makes use of
asynchronous signals and GDB is using displaced stepping.
The problem can be found in displaced_step_buffers::finish in
displaced-stepping.c, and is this; after GDB tries to perform a
displaced step, and the inferior stops, GDB classifies the stop into
one of two states, either the displaced step succeeded, or the
displaced step failed.
If the displaced step succeeded then gdbarch_displaced_step_fixup is
called, which has the job of fixing up the state of the current
inferior as if the step had not been performed in a displaced manner.
This all seems just fine.
However, if the displaced step is considered to have not completed
then GDB doesn't call gdbarch_displaced_step_fixup, instead GDB
remains in displaced_step_buffers::finish and just performs a minimal
fixup which involves adjusting the program counter back to its
original value.
The problem here is that for amd64 and ARM setting up for a displaced
step can involve changing the values in some temporary registers. If
the displaced step succeeds then this is fine; after the step the
temporary registers are restored to their original values in the
architecture specific code.
But if the displaced step does not succeed then the temporary
registers are never restored, and they retain their modified values.
In this context a temporary register is simply any register that is
not otherwise used by the instruction being stepped that the
architecture specific code considers safe to borrow for the lifetime
of the instruction being stepped.
In the bug PR gdb/22921, the amd64 instruction being stepped is
an rip-relative instruction like this:
jmp *0x2fe2(%rip)
When we displaced step this instruction we borrow a register, and
modify the instruction to something like:
jmp *0x2fe2(%rcx)
with %rcx having its value adjusted to contain the original %rip
value.
Now if the displaced step does not succeed, then %rcx will be left
with a corrupted value. Obviously corrupting any register is bad; in
the bug report this problem was spotted because %rcx is used as a
function argument register.
And finally, why might a displaced step not succeed? Asynchronous
signals provides one reason. GDB sets up for the displaced step and,
at that precise moment, the OS delivers a signal (SIGALRM in the bug
report), the signal stops the inferior at the address of the displaced
instruction. GDB cancels the displaced instruction, handles the
signal, and then tries again with the displaced step. But it is that
first cancellation of the displaced step that causes the problem; in
that case GDB (correctly) sees the displaced step as having not
completed, and so does not perform the architecture specific fixup,
leaving the register corrupted.
The reason why I think AArch64, rs600, i386, and s390 are not effected
by this problem is that I don't believe these architectures make use
of any temporary registers, so when a displaced step is not completed
successfully, the minimal fix up is sufficient.
On amd64 we use at most one temporary register.
On ARM, looking at arm_displaced_step_copy_insn_closure, we could
modify up to 16 temporary registers, and the instruction being
displaced stepped could be expanded to multiple replacement
instructions, which increases the chances of this bug triggering.
This commit only aims to address the issue on amd64 for now, though I
believe that the approach I'm proposing here might be applicable for
ARM too.
What I propose is that we always call gdbarch_displaced_step_fixup.
We will now pass an extra argument to gdbarch_displaced_step_fixup,
this a boolean that indicates whether GDB thinks the displaced step
completed successfully or not.
When this flag is false this indicates that the displaced step halted
for some "other" reason. On ARM GDB can potentially read the
inferior's program counter in order figure out how far through the
sequence of replacement instructions we got, and from that GDB can
figure out what fixup needs to be performed.
On targets like amd64 the problem is slightly easier as displaced
stepping only uses a single replacement instruction. If the displaced
step didn't complete the GDB knows that the single instruction didn't
execute.
The point is that by always calling gdbarch_displaced_step_fixup, each
architecture can now ensure that the inferior state is fixed up
correctly in all cases, not just the success case.
On amd64 this ensures that we always restore the temporary register
value, and so bug PR gdb/22921 is resolved.
In order to move all architectures to this new API, I have moved the
minimal roll-back version of the code inside the architecture specific
fixup functions for AArch64, rs600, s390, and ARM. For all of these
except ARM I think this is good enough, as no temporaries are used all
that's needed is the program counter restore anyway.
For ARM the minimal code is no worse than what we had before, though I
do consider this architecture's displaced-stepping broken.
I've updated the gdb.arch/amd64-disp-step.exp test to cover the
'jmpq*' instruction that was causing problems in the original bug, and
also added support for testing the displaced step in the presence of
asynchronous signal delivery.
I've also added two new tests (for amd64 and i386) that check that GDB
can correctly handle displaced stepping over a single instruction that
branches to itself. I added these tests after a first version of this
patch relied too much on checking the program-counter value in order
to see if the displaced instruction had executed. This works fine in
almost all cases, but when an instruction branches to itself a pure
program counter check is not sufficient. The new tests expose this
problem.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=22921
Approved-By: Pedro Alves <pedro@palves.net>
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It was pointed out during review of another patch that the function
displaced_step_dump_bytes really isn't specific to displaced stepping,
and should really get a more generic name and move into gdbsupport/.
This commit does just that. The function is renamed to
bytes_to_string and is moved into gdbsupport/common-utils.{cc,h}. The
function implementation doesn't really change. Much...
... I have updated the function to take an array view, which makes it
slightly easier to call in a couple of places where we already have a
gdb::bytes_vector. I've then added an inline wrapper to convert a raw
pointer and length into an array view, which is used in places where
we don't easily have a gdb::bytes_vector (or similar).
Updated all users of displaced_step_dump_bytes.
There should be no user visible changes after this commit.
Finally, I ended up having to add an include of gdb_assert.h into
array-view.h. When I include array-view.h into common-utils.h I ran
into build problems because array-view.h calls gdb_assert.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
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This turns many functions that are related to optimized-out or
availability-checking to be methods of value. The static function
value_entirely_covered_by_range_vector is also converted to be a
private method.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
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This turns the remaining value_contents functions -- value_contents,
value_contents_all, value_contents_for_printing, and
value_contents_for_printing_const -- into methods of value. It also
converts the static functions require_not_optimized_out and
require_available to be private methods.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
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This turns allocate_optimized_out_value into a static "constructor" of
value.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
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This changes value_offset to be a method of value. Much of this patch
was written by script.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
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This changes value_type to be a method of value. Much of this patch
was written by script.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
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It's currently not clear how the ownership of gdbarch_tdep objects
works. In fact, nothing ever takes ownership of it. This is mostly
fine because we never free gdbarch objects, and thus we never free
gdbarch_tdep objects. There is an exception to that however: when
initialization fails, we do free the gdbarch object that is not going to
be used, and we free the tdep too. Currently, i386 and s390 do it.
To make things clearer, change gdbarch_alloc so that it takes ownership
of the tdep. The tdep is thus automatically freed if the gdbarch is
freed.
Change all gdbarch initialization functions to pass a new gdbarch_tdep
object to gdbarch_alloc and then retrieve a non-owning reference from
the gdbarch object.
Before this patch, the xtensa architecture had a single global instance
of xtensa_gdbarch_tdep. Since we need to pass a dynamically allocated
gdbarch_tdep_base instance to gdbarch_alloc, remove this global
instance, and dynamically allocate one as needed, like we do for all
other architectures. Make the `rmap` array externally visible and
rename it to the less collision-prone `xtensa_rmap` name.
Change-Id: Id3d70493ef80ce4bdff701c57636f4c79ed8aea2
Approved-By: Andrew Burgess <aburgess@redhat.com>
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This commit is the result of running the gdb/copyright.py script,
which automated the update of the copyright year range for all
source files managed by the GDB project to be updated to include
year 2023.
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On s390x-linux with target board unix/-m31, I run into:
...
(gdb) PASS: gdb.guile/scm-lazy-string.exp: bad length
print ptr^M
$1 = 0x804006b0 <error: Cannot access memory at address 0x804006b0>^M
(gdb) FAIL: gdb.guile/scm-lazy-string.exp: ptr: print ptr
...
A minimal example is:
...
$ gdb -q -batch -ex "set trace-commands on" -x gdb.in
+file scm-lazy-string
+break main
Breakpoint 1 at 0x4005d2: file scm-lazy-string.c, line 23.
+run
Breakpoint 1, main () at scm-lazy-string.c:23
23 const char *ptr = "pointer";
+step
24 const char array[] = "array";
+print ptr
$1 = 0x804006b0 <error: Cannot access memory at address 0x804006b0>
...
If we delete the breakpoint after running to it, we have instead the expected:
...
+delete
+step
24 const char array[] = "array";
+print ptr
$1 = 0x4006b0 "pointer"
...
The problem is in displaced stepping, forced by the presence of the breakpoint,
when stepping over this insn:
...
0x4005d2 <main+10> larl %r1,0x4006b0
...
With normal stepping we have:
...
(gdb) p /x $r1
$2 = 0x3ff004006b0
...
but with displaced stepping we have instead (note the 0x80000000 difference):
...
(gdb) p /x $r1
$1 = 0x3ff804006b0
(gdb)
...
The difference comes from this code in s390_displaced_step_fixup:
...
/* Handle LOAD ADDRESS RELATIVE LONG. */
else if (is_ril (insn, op1_larl, op2_larl, &r1, &i2))
{
/* Update PC. */
regcache_write_pc (regs, from + insnlen);
/* Recompute output address in R1. */
regcache_cooked_write_unsigned (regs, S390_R0_REGNUM + r1,
amode | (from + i2 * 2));
}
...
where the "amode |" adds the 0x80000000.
Fix this by removing the "amode |".
Tested on s390-linux, with native and target board unix/-m31.
Approved-By: Ulrich Weigand <uweigand@de.ibm.com>
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Currently, every internal_error call must be passed __FILE__/__LINE__
explicitly, like:
internal_error (__FILE__, __LINE__, "foo %d", var);
The need to pass in explicit __FILE__/__LINE__ is there probably
because the function predates widespread and portable variadic macros
availability. We can use variadic macros nowadays, and in fact, we
already use them in several places, including the related
gdb_assert_not_reached.
So this patch renames the internal_error function to something else,
and then reimplements internal_error as a variadic macro that expands
__FILE__/__LINE__ itself.
The result is that we now should call internal_error like so:
internal_error ("foo %d", var);
Likewise for internal_warning.
The patch adjusts all calls sites. 99% of the adjustments were done
with a perl/sed script.
The non-mechanical changes are in gdbsupport/errors.h,
gdbsupport/gdb_assert.h, and gdb/gdbarch.py.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Change-Id: Ia6f372c11550ca876829e8fd85048f4502bdcf06
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This changes GDB to use frame_info_ptr instead of frame_info *
The substitution was done with multiple sequential `sed` commands:
sed 's/^struct frame_info;/class frame_info_ptr;/'
sed 's/struct frame_info \*/frame_info_ptr /g' - which left some
issues in a few files, that were manually fixed.
sed 's/\<frame_info \*/frame_info_ptr /g'
sed 's/frame_info_ptr $/frame_info_ptr/g' - used to remove whitespace
problems.
The changed files were then manually checked and some 'sed' changes
undone, some constructors and some gets were added, according to what
made sense, and what Tromey originally did
Co-Authored-By: Bruno Larsen <blarsen@redhat.com>
Approved-by: Tom Tomey <tom@tromey.com>
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Remove the macro, replace all uses with calls to type::length.
Change-Id: Ib9bdc954576860b21190886534c99103d6a47afb
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Remove the macro, replace all uses by calls to type::target_type.
Change-Id: Ie51d3e1e22f94130176d6abd723255282bb6d1ed
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This removes the deprecated register_gdbarch_init in favor a default
argument to gdbarch_register. Regression tested on x86-64 Fedora 34.
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I built GDB for all targets on a x86-64/GNU-Linux system, and
then (accidentally) passed GDB a RISC-V binary, and asked GDB to "run"
the binary on the native target. I got this error:
(gdb) show architecture
The target architecture is set to "auto" (currently "i386").
(gdb) file /tmp/hello.rv32.exe
Reading symbols from /tmp/hello.rv32.exe...
(gdb) show architecture
The target architecture is set to "auto" (currently "riscv:rv32").
(gdb) run
Starting program: /tmp/hello.rv32.exe
../../src/gdb/i387-tdep.c:596: internal-error: i387_supply_fxsave: Assertion `tdep->st0_regnum >= I386_ST0_REGNUM' failed.
What's going on here is this; initially the architecture is i386, this
is based on the default architecture, which is set based on the native
target. After loading the RISC-V executable the architecture of the
current inferior is updated based on the architecture of the
executable.
When we "run", GDB does a fork & exec, with the inferior being
controlled through ptrace. GDB sees an initial stop from the inferior
as soon as the inferior comes to life. In response to this stop GDB
ends up calling save_stop_reason (linux-nat.c), which ends up trying
to read register from the inferior, to do this we end up calling
target_ops::fetch_registers, which, for the x86-64 native target,
calls amd64_linux_nat_target::fetch_registers.
After this I eventually end up in i387_supply_fxsave, different x86
based targets will end in different functions to fetch registers, but
it doesn't really matter which function we end up in, the problem is
this line, which is repeated in many places:
i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
The problem here is that the ARCH in this line comes from the current
inferior, which, as we discussed above, will be a RISC-V gdbarch, the
tdep field will actually be of type riscv_gdbarch_tdep, not
i386_gdbarch_tdep. After this cast we are relying on undefined
behaviour, in my case I happen to trigger an assert, but this might
not always be the case.
The thing I tried that exposed this problem was of course, trying to
start an executable of the wrong architecture on a native target. I
don't think that the correct solution for this problem is to detect,
at the point of cast, that the gdbarch_tdep object is of the wrong
type, but, I did wonder, is there a way that we could protect
ourselves from incorrectly casting the gdbarch_tdep object?
I think that there is something we can do here, and this commit is the
first step in that direction, though no actual check is added by this
commit.
This commit can be split into two parts:
(1) In gdbarch.h and arch-utils.c. In these files I have modified
gdbarch_tdep (the function) so that it now takes a template argument,
like this:
template<typename TDepType>
static inline TDepType *
gdbarch_tdep (struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep_1 (gdbarch);
return static_cast<TDepType *> (tdep);
}
After this change we are no better protected, but the cast is now
done within the gdbarch_tdep function rather than at the call sites,
this leads to the second, much larger change in this commit,
(2) Everywhere gdbarch_tdep is called, we make changes like this:
- i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
+ i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (arch);
There should be no functional change after this commit.
In the next commit I will build on this change to add an assertion in
gdbarch_tdep that checks we are casting to the correct type.
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Change gdbarch_register_reggroup_p to take a 'const struct reggroup *'
argument. This requires a change to the gdb/gdbarch-components.py
script, regeneration of gdbarch.{c,h}, and then updates to all the
architectures that implement this method.
There should be no user visible changes after this commit.
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It is better to rename floatformats_ia64_quad to floatformats_ieee_quad
to reflect the reality, and then we can clean up the related code.
As Tom Tromey said [1]:
These files are maintained in gcc and then imported into the
binutils-gdb repository, so any changes to them will have to
be proposed there first.
the related changes have been merged into gcc master now [2], it is time
to do it for gdb.
[1] https://sourceware.org/pipermail/gdb-patches/2022-March/186569.html
[2] https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=b2dff6b2d9d6
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
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Now that filtered and unfiltered output can be treated identically, we
can unify the printf family of functions. This is done under the name
"gdb_printf". Most of this patch was written by script.
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This commit brings all the changes made by running gdb/copyright.py
as per GDB's Start of New Year Procedure.
For the avoidance of doubt, all changes in this commits were
performed by the script.
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The process record code often emits unfiltered output. In some cases,
this output ought to go to gdb_stderr (but see below). In other
cases, the output is guarded by a logging variable and so ought to go
to gdb_stdlog. This patch makes these changes.
Note that in many cases, the output to stderr is followed by a
"return -1", which is how process record indicates an error. It seems
to me that calling error here would be preferable, because, in many
cases, that's all the caller does when it sees a -1. However, I
haven't made this change.
This is part of PR gdb/7233.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=7233
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I would like to be able to use non-trivial types in gdbarch_tdep types.
This is not possible at the moment (in theory), because of the one
definition rule.
To allow it, rename all gdbarch_tdep types to <arch>_gdbarch_tdep, and
make them inherit from a gdbarch_tdep base class. The inheritance is
necessary to be able to pass pointers to all these <arch>_gdbarch_tdep
objects to gdbarch_alloc, which takes a pointer to gdbarch_tdep.
These objects are never deleted through a base class pointer, so I
didn't include a virtual destructor. In the future, if gdbarch objects
deletable, I could imagine that the gdbarch_tdep objects could become
owned by the gdbarch objects, and then it would become useful to have a
virtual destructor (so that the gdbarch object can delete the owned
gdbarch_tdep object). But that's not necessary right now.
It turns out that RISC-V already has a gdbarch_tdep that is
non-default-constructible, so that provides a good motivation for this
change.
Most changes are fairly straightforward, mostly needing to add some
casts all over the place. There is however the xtensa architecture,
doing its own little weird thing to define its gdbarch_tdep. I did my
best to adapt it, but I can't test those changes.
Change-Id: Ic001903f91ddd106bd6ca09a79dabe8df2d69f3b
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The bug fixed by this [1] patch was caused by an out-of-bounds access to
a value's content. The code gets the value's content (just a pointer)
and then indexes it with a non-sensical index.
This made me think of changing functions that return value contents to
return array_views instead of a plain pointer. This has the advantage
that when GDB is built with _GLIBCXX_DEBUG, accesses to the array_view
are checked, making bugs more apparent / easier to find.
This patch changes the return types of these functions, and updates
callers to call .data() on the result, meaning it's not changing
anything in practice. Additional work will be needed (which can be done
little by little) to make callers propagate the use of array_view and
reap the benefits.
[1] https://sourceware.org/pipermail/gdb-patches/2021-September/182306.html
Change-Id: I5151f888f169e1c36abe2cbc57620110673816f3
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According to bug 28056, running an s390x binary gives:
(gdb) run
Starting program: /usr/bin/ls
/home/ubuntu/tmp/gdb-11.0.90.20210705/gdb/linux-tdep.c:2550: internal-error: displaced_step_prepare_status linux_displaced_step_prepare(gdbarch*, thread_info*, CORE_ADDR&): Assertion `gdbarch_data->num_disp_step_buffers > 0' failed.
This is because the s390 architecture registers some Linux-specific
displaced stepping callbacks in the OS-agnostic s390_gdbarch_init:
set_gdbarch_displaced_step_prepare (gdbarch, linux_displaced_step_prepare);
set_gdbarch_displaced_step_finish (gdbarch, linux_displaced_step_finish);
set_gdbarch_displaced_step_restore_all_in_ptid
(gdbarch, linux_displaced_step_restore_all_in_ptid);
But then the Linux-specific s390_linux_init_abi_any passes
num_disp_step_buffers=0 to linux_init_abi:
linux_init_abi (info, gdbarch, 0);
The problem happens when linux_displaced_step_prepare is called for the
first time. It tries to allocate the displaced stepping buffers, but
sees that the number of displaced stepping buffers for that architecture
is 0, which is unexpected / invalid.
s390_gdbarch_init should not register the linux_* callbacks, that is
expected to be done by linux_init_abi. If debugging a bare-metal s390
program, or an s390 program on another OS GDB doesn't know about, we
wouldn't want to use them. We would either register no callbacks, if
displaced stepping isn't supported, or register a different set of
callbacks if we wanted to support displaced stepping in those cases.
The commit that refactored the displaced stepping machinery and
introduced these set_gdbarch_displaced_step_* calls is 187b041e2514
("gdb: move displaced stepping logic to gdbarch, allow starting
concurrent displaced steps"). However, even before that,
s390_gdbarch_init did:
set_gdbarch_displaced_step_location (gdbarch, linux_displaced_step_location);
... which already seemed wrong. The Linux-specific callback was used
even for non-Linux system. Maybe that was on purpose, because it would
also happen to work in some other non-Linux case, or maybe it was simply
a mistake. I'll assume that this was a small mistake when
s390-tdep.{h,c} where factored out of s390-linux-tdep.c, in d6e589456475
("s390: Split up s390-linux-tdep.c into two files").
Fix this by removing the setting of these displaced step callbacks from
s390_gdbarch_init. Instead, pass num_disp_step_buffers=1 to
linux_init_abi, in s390_linux_init_abi_any. Doing so will cause
linux_init_abi to register these same callbacks. It will also mean that
when debugging a bare-metal s390 executable or an executable on another
OS that GDB doesn't know about, gdbarch_displaced_step_prepare won't be
set, so displaced stepping won't be used.
This patch will need to be merged in the gdb-11-branch, since this is a
GDB 11 regression, so here's the ChangeLog entry:
gdb/ChangeLog:
* s390-linux-tdep.c (s390_linux_init_abi_any): Pass 1 (number
of displaced stepping buffers to linux_init_abi.
* s390-tdep.c (s390_gdbarch_init): Don't set the Linux-specific
displaced-stepping gdbarch callbacks.
Change-Id: Ieab2f8990c78fde845ce7378d6fd4ee2833800d5
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28056
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I wrote this while debugging a problem where the expected unwinder for a
frame wasn't used. It adds messages to show which unwinders are
considered for a frame, why they are not selected (if an exception is
thrown), and finally which unwinder is selected in the end.
To be able to show a meaningful, human-readable name for the unwinders,
add a "name" field to struct frame_unwind, and update all instances to
include a name.
Here's an example of the output:
[frame] frame_unwind_find_by_frame: this_frame=0
[frame] frame_unwind_try_unwinder: trying unwinder "dummy"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "dwarf2 tailcall"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "inline"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "jit"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "python"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "amd64 epilogue"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "i386 epilogue"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "dwarf2"
[frame] frame_unwind_try_unwinder: yes
gdb/ChangeLog:
* frame-unwind.h (struct frame_unwind) <name>: New. Update
instances everywhere to include this field.
* frame-unwind.c (frame_unwind_try_unwinder,
frame_unwind_find_by_frame): Add debug messages.
Change-Id: I813f17777422425f0d08b22499817b23922e8ddb
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I wrote a small script to spot a pattern of indentation mistakes I saw
happened in breakpoint.c. And while at it I ran it on all files and
fixed what I found. No behavior changes intended, just indentation and
addition / removal of curly braces.
gdb/ChangeLog:
* Fix some indentation mistakes throughout.
gdbserver/ChangeLog:
* Fix some indentation mistakes throughout.
Change-Id: Ia01990c26c38e83a243d8f33da1d494f16315c6e
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The current_top_target function is a hidden dependency on the current
inferior. Since I'd like to slowly move towards reducing our dependency
on the global current state, remove this function and make callers use
current_inferior ()->top_target ()
There is no expected change in behavior, but this one step towards
making those callers use the inferior from their context, rather than
refer to the global current inferior.
gdb/ChangeLog:
* target.h (current_top_target): Remove, make callers use the
current inferior instead.
* target.c (current_top_target): Remove.
Change-Id: Iccd457036f84466cdaa3865aa3f9339a24ea001d
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The code to access the target section table can be made more const, so
lets do that. There should be no user visible changes after this
commit.
gdb/ChangeLog:
* gdb/bfd-target.c (class target_bfd) <get_section_table>: Make
return type const.
* gdb/exec.c (struct exec_target) <get_section_table>: Likewise.
(section_table_read_available_memory): Make local const.
(exec_target::xfer_partial): Make local const.
(print_section_info): Make parameter const.
* gdb/exec.h (print_section_info): Likewise.
* gdb/ppc64-tdep.c (ppc64_convert_from_func_ptr_addr): Make local
const.
* gdb/record-btrace.c (record_btrace_target::xfer_partial):
Likewise.
* gdb/remote.c (remote_target::remote_xfer_live_readonly_partial):
Likewise.
* gdb/s390-tdep.c (s390_load): Likewise.
* gdb/solib-dsbt.c (scan_dyntag): Likewise.
* gdb/solib-svr4.c (scan_dyntag): Likewise.
* gdb/target-debug.h (target_debug_print_target_section_table_p):
Rename to...
(target_debug_print_const_target_section_table_p): ...this.
* gdb/target-delegates.c: Regenerate.
* gdb/target.c (target_get_section_table): Make return type const.
(target_section_by_addr): Likewise. Also make some locals const.
(memory_xfer_partial_1): Make some locals const.
* gdb/target.h (struct target_ops) <get_section_table>: Make
return type const.
(target_section_by_addr): Likewise.
(target_get_section_table): Likewise.
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With the new member functions for struct trad_frame_saved_reg, there is no
need to invoke some of the set/get functions anymore. This patch removes
those and adjusts all callers.
Even though the most natural initial state of a saved register value is
UNKNOWN, there are target backends relying on the previous initial state
of REALREG set to a register's own number. I noticed this in at least a
couple targets: aarch64 and riscv.
Because of that, I decided to keep the reset function that sets the set of
register values to REALREG. I can't exercise all the targets to make sure
the initial state change won't break things, hence why it is risky to change
the default.
Validated with --enable-targets=all on aarch64-linux Ubuntu 18.04/20.04.
gdb/ChangeLog
2021-01-19 Luis Machado <luis.machado@linaro.org>
* trad-frame.h (trad_frame_saved_reg) <set_value_bytes>: Allocate
memory and save data.
(trad_frame_set_value, trad_frame_set_realreg, trad_frame_set_addr)
(trad_frame_set_unknown, trad_frame_set_value_bytes)
(trad_frame_value_p, trad_frame_addr_p, trad_frame_realreg_p)
(trad_frame_value_bytes_p): Remove.
(trad_frame_reset_saved_regs): Adjust documentation.
* trad-frame.c (trad_frame_alloc_saved_regs): Initialize via a
constructor and reset the state of the registers.
(trad_frame_value_p, trad_frame_addr_p, trad_frame_realreg_p)
(trad_frame_value_bytes_p, trad_frame_set_value)
(trad_frame_set_realreg, trad_frame_set_addr)
(trad_frame_set_unknown, trad_frame_set_value_bytes): Remove.
(trad_frame_set_reg_realreg): Update to call member function.
(trad_frame_set_reg_addr, trad_frame_set_reg_value_bytes): Likewise.
(trad_frame_get_prev_register): Likewise.
* aarch64-tdep.c (aarch64_analyze_prologue)
(aarch64_analyze_prologue_test, aarch64_make_prologue_cache_1)
(aarch64_prologue_prev_register): Update to use member functions.
* alpha-mdebug-tdep.c (alpha_mdebug_frame_unwind_cache): Likewise.
* alpha-tdep.c (alpha_heuristic_frame_unwind_cache): Likewise.
* arc-tdep.c (arc_print_frame_cache, arc_make_frame_cache): Likewise.
* arm-tdep.c (arm_make_prologue_cache, arm_exidx_fill_cache)
(arm_make_epilogue_frame_cache): Likewise.
* avr-tdep.c (avr_frame_unwind_cache)
(avr_frame_prev_register): Likewise.
* cris-tdep.c (cris_scan_prologue): Likewise.
* csky-tdep.c (csky_frame_unwind_cache): Likewise.
* frv-tdep.c (frv_analyze_prologue): Likewise.
* hppa-tdep.c (hppa_frame_cache, hppa_fallback_frame_cache): Likewise.
* lm32-tdep.c (lm32_frame_cache): Likewise.
* m32r-tdep.c (m32r_frame_unwind_cache): Likewise.
* m68hc11-tdep.c (m68hc11_frame_unwind_cache): Likewise.
* mips-tdep.c (set_reg_offset, mips_insn16_frame_cache)
(mips_micro_frame_cache, mips_insn32_frame_cache): Likewise.
(reset_saved_regs): Adjust to set realreg.
* riscv-tdep.c (riscv_scan_prologue, riscv_frame_cache): Adjust to
call member functions.
* rs6000-tdep.c (rs6000_frame_cache, rs6000_epilogue_frame_cache)
* s390-tdep.c (s390_prologue_frame_unwind_cache)
(s390_backchain_frame_unwind_cache): Likewise.
* score-tdep.c (score7_analyze_prologue)
(score3_analyze_prologue, score_make_prologue_cache): Likewise.
* sparc-netbsd-tdep.c (sparc32nbsd_sigcontext_saved_regs): Likewise.
* sparc-sol2-tdep.c (sparc32_sol2_sigtramp_frame_cache): Likewise.
* sparc64-netbsd-tdep.c (sparc64nbsd_sigcontext_saved_regs): Likewise.
* sparc64-sol2-tdep.c (sparc64_sol2_sigtramp_frame_cache): Likewise.
* tilegx-tdep.c (tilegx_analyze_prologue)
(tilegx_frame_cache): Likewise.
* v850-tdep.c (v850_frame_cache): Likewise.
* vax-tdep.c (vax_frame_cache): Likewise.
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The following patch drops the overloading going on with the trad_frame_saved_reg
struct and defines a new struct with a KIND enum and a union of different
fields.
The new struct looks like this:
struct trad_frame_saved_reg
{
setters/getters
...
private:
trad_frame_saved_reg_kind m_kind;
union {
LONGEST value;
int realreg;
LONGEST addr;
const gdb_byte *value_bytes;
} m_reg;
};
And the enums look like this:
/* Describes the kind of encoding a stored register has. */
enum class trad_frame_saved_reg_kind
{
/* Register value is unknown. */
UNKNOWN = 0,
/* Register value is a constant. */
VALUE,
/* Register value is in another register. */
REALREG,
/* Register value is at an address. */
ADDR,
/* Register value is a sequence of bytes. */
VALUE_BYTES
};
The patch also adds setters/getters and updates all the users of the old
struct.
It is worth mentioning that due to the previous overloaded nature of the
fields, some tdep files like to store negative offsets and indexes in the ADDR
field, so I kept the ADDR as LONGEST instead of CORE_ADDR. Those cases may
be better supported by a new enum entry.
I have not addressed those cases in this patch to prevent unwanted breakage,
given I have no way to test some of the targets. But it would be nice to
clean those up eventually.
The change to frame-unwind.* is to constify the parameter being passed to the
unwinding functions, given we now accept a "const gdb_byte *" for value bytes.
Tested on aarch64-linux/Ubuntu 20.04/18.04 and by building GDB with
--enable-targets=all.
gdb/ChangeLog:
2021-01-04 Luis Machado <luis.machado@linaro.org>
Update all users of trad_frame_saved_reg to use the new member
functions.
Remote all struct keywords from declarations of trad_frame_saved_reg
types, except on forward declarations.
* aarch64-tdep.c: Update.
* alpha-mdebug-tdep.c: Update.
* alpha-tdep.c: Update.
* arc-tdep.c: Update.
* arm-tdep.c: Update.
* avr-tdep.c: Update.
* cris-tdep.c: Update.
* csky-tdep.c: Update.
* frv-tdep.c: Update.
* hppa-linux-tdep.c: Update.
* hppa-tdep.c: Update.
* hppa-tdep.h: Update.
* lm32-tdep.c: Update.
* m32r-linux-tdep.c: Update.
* m32r-tdep.c: Update.
* m68hc11-tdep.c: Update.
* mips-tdep.c: Update.
* moxie-tdep.c: Update.
* riscv-tdep.c: Update.
* rs6000-tdep.c: Update.
* s390-linux-tdep.c: Update.
* s390-tdep.c: Update.
* score-tdep.c: Update.
* sparc-netbsd-tdep.c: Update.
* sparc-sol2-tdep.c: Update.
* sparc64-fbsd-tdep.c: Update.
* sparc64-netbsd-tdep.c: Update.
* sparc64-obsd-tdep.c: Update.
* sparc64-sol2-tdep.c: Update.
* tilegx-tdep.c: Update.
* v850-tdep.c: Update.
* vax-tdep.c: Update.
* frame-unwind.c (frame_unwind_got_bytes): Make parameter const.
* frame-unwind.h (frame_unwind_got_bytes): Likewise.
* trad-frame.c: Update.
Remove TF_REG_* enum.
(trad_frame_alloc_saved_regs): Add a static assertion to check for
a trivially-constructible struct.
(trad_frame_reset_saved_regs): Adjust to use member function.
(trad_frame_value_p): Likewise.
(trad_frame_addr_p): Likewise.
(trad_frame_realreg_p): Likewise.
(trad_frame_value_bytes_p): Likewise.
(trad_frame_set_value): Likewise.
(trad_frame_set_realreg): Likewise.
(trad_frame_set_addr): Likewise.
(trad_frame_set_unknown): Likewise.
(trad_frame_set_value_bytes): Likewise.
(trad_frame_get_prev_register): Likewise.
* trad-frame.h: Update.
(trad_frame_saved_reg_kind): New enum.
(struct trad_frame_saved_reg) <addr, realreg, data>: Remove.
<m_kind, m_reg>: New member fields.
<set_value, set_realreg, set_addr, set_unknown, set_value_bytes>
<kind, value, realreg, addr, value_bytes, is_value, is_realreg>
<is_addr, is_unknown, is_value_bytes>: New member functions.
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This commits the result of running gdb/copyright.py as per our Start
of New Year procedure...
gdb/ChangeLog
Update copyright year range in copyright header of all GDB files.
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displaced steps
Today, GDB only allows a single displaced stepping operation to happen
per inferior at a time. There is a single displaced stepping buffer per
inferior, whose address is fixed (obtained with
gdbarch_displaced_step_location), managed by infrun.c.
In the case of the AMD ROCm target [1] (in the context of which this
work has been done), it is typical to have thousands of threads (or
waves, in SMT terminology) executing the same code, hitting the same
breakpoint (possibly conditional) and needing to to displaced step it at
the same time. The limitation of only one displaced step executing at a
any given time becomes a real bottleneck.
To fix this bottleneck, we want to make it possible for threads of a
same inferior to execute multiple displaced steps in parallel. This
patch builds the foundation for that.
In essence, this patch moves the task of preparing a displaced step and
cleaning up after to gdbarch functions. This allows using different
schemes for allocating and managing displaced stepping buffers for
different platforms. The gdbarch decides how to assign a buffer to a
thread that needs to execute a displaced step.
On the ROCm target, we are able to allocate one displaced stepping
buffer per thread, so a thread will never have to wait to execute a
displaced step.
On Linux, the entry point of the executable if used as the displaced
stepping buffer, since we assume that this code won't get used after
startup. From what I saw (I checked with a binary generated against
glibc and musl), on AMD64 we have enough space there to fit two
displaced stepping buffers. A subsequent patch makes AMD64/Linux use
two buffers.
In addition to having multiple displaced stepping buffers, there is also
the idea of sharing displaced stepping buffers between threads. Two
threads doing displaced steps for the same PC could use the same buffer
at the same time. Two threads stepping over the same instruction (same
opcode) at two different PCs may also be able to share a displaced
stepping buffer. This is an idea for future patches, but the
architecture built by this patch is made to allow this.
Now, the implementation details. The main part of this patch is moving
the responsibility of preparing and finishing a displaced step to the
gdbarch. Before this patch, preparing a displaced step is driven by the
displaced_step_prepare_throw function. It does some calls to the
gdbarch to do some low-level operations, but the high-level logic is
there. The steps are roughly:
- Ask the gdbarch for the displaced step buffer location
- Save the existing bytes in the displaced step buffer
- Ask the gdbarch to copy the instruction into the displaced step buffer
- Set the pc of the thread to the beginning of the displaced step buffer
Similarly, the "fixup" phase, executed after the instruction was
successfully single-stepped, is driven by the infrun code (function
displaced_step_finish). The steps are roughly:
- Restore the original bytes in the displaced stepping buffer
- Ask the gdbarch to fixup the instruction result (adjust the target's
registers or memory to do as if the instruction had been executed in
its original location)
The displaced_step_inferior_state::step_thread field indicates which
thread (if any) is currently using the displaced stepping buffer, so it
is used by displaced_step_prepare_throw to check if the displaced
stepping buffer is free to use or not.
This patch defers the whole task of preparing and cleaning up after a
displaced step to the gdbarch. Two new main gdbarch methods are added,
with the following semantics:
- gdbarch_displaced_step_prepare: Prepare for the given thread to
execute a displaced step of the instruction located at its current PC.
Upon return, everything should be ready for GDB to resume the thread
(with either a single step or continue, as indicated by
gdbarch_displaced_step_hw_singlestep) to make it displaced step the
instruction.
- gdbarch_displaced_step_finish: Called when the thread stopped after
having started a displaced step. Verify if the instruction was
executed, if so apply any fixup required to compensate for the fact
that the instruction was executed at a different place than its
original pc. Release any resources that were allocated for this
displaced step. Upon return, everything should be ready for GDB to
resume the thread in its "normal" code path.
The displaced_step_prepare_throw function now pretty much just offloads
to gdbarch_displaced_step_prepare and the displaced_step_finish function
offloads to gdbarch_displaced_step_finish.
The gdbarch_displaced_step_location method is now unnecessary, so is
removed. Indeed, the core of GDB doesn't know how many displaced step
buffers there are nor where they are.
To keep the existing behavior for existing architectures, the logic that
was previously implemented in infrun.c for preparing and finishing a
displaced step is moved to displaced-stepping.c, to the
displaced_step_buffer class. Architectures are modified to implement
the new gdbarch methods using this class. The behavior is not expected
to change.
The other important change (which arises from the above) is that the
core of GDB no longer prevents concurrent displaced steps. Before this
patch, start_step_over walks the global step over chain and tries to
initiate a step over (whether it is in-line or displaced). It follows
these rules:
- if an in-line step is in progress (in any inferior), don't start any
other step over
- if a displaced step is in progress for an inferior, don't start
another displaced step for that inferior
After starting a displaced step for a given inferior, it won't start
another displaced step for that inferior.
In the new code, start_step_over simply tries to initiate step overs for
all the threads in the list. But because threads may be added back to
the global list as it iterates the global list, trying to initiate step
overs, start_step_over now starts by stealing the global queue into a
local queue and iterates on the local queue. In the typical case, each
thread will either:
- have initiated a displaced step and be resumed
- have been added back by the global step over queue by
displaced_step_prepare_throw, because the gdbarch will have returned
that there aren't enough resources (i.e. buffers) to initiate a
displaced step for that thread
Lastly, if start_step_over initiates an in-line step, it stops
iterating, and moves back whatever remaining threads it had in its local
step over queue to the global step over queue.
Two other gdbarch methods are added, to handle some slightly annoying
corner cases. They feel awkwardly specific to these cases, but I don't
see any way around them:
- gdbarch_displaced_step_copy_insn_closure_by_addr: in
arm_pc_is_thumb, arm-tdep.c wants to get the closure for a given
buffer address.
- gdbarch_displaced_step_restore_all_in_ptid: when a process forks
(at least on Linux), the address space is copied. If some displaced
step buffers were in use at the time of the fork, we need to restore
the original bytes in the child's address space.
These two adjustments are also made in infrun.c:
- prepare_for_detach: there may be multiple threads doing displaced
steps when we detach, so wait until all of them are done
- handle_inferior_event: when we handle a fork event for a given
thread, it's possible that other threads are doing a displaced step at
the same time. Make sure to restore the displaced step buffer
contents in the child for them.
[1] https://github.com/ROCm-Developer-Tools/ROCgdb
gdb/ChangeLog:
* displaced-stepping.h (struct
displaced_step_copy_insn_closure): Adjust comments.
(struct displaced_step_inferior_state) <step_thread,
step_gdbarch, step_closure, step_original, step_copy,
step_saved_copy>: Remove fields.
(struct displaced_step_thread_state): New.
(struct displaced_step_buffer): New.
* displaced-stepping.c (displaced_step_buffer::prepare): New.
(write_memory_ptid): Move from infrun.c.
(displaced_step_instruction_executed_successfully): New,
factored out of displaced_step_finish.
(displaced_step_buffer::finish): New.
(displaced_step_buffer::copy_insn_closure_by_addr): New.
(displaced_step_buffer::restore_in_ptid): New.
* gdbarch.sh (displaced_step_location): Remove.
(displaced_step_prepare, displaced_step_finish,
displaced_step_copy_insn_closure_by_addr,
displaced_step_restore_all_in_ptid): New.
* gdbarch.c: Re-generate.
* gdbarch.h: Re-generate.
* gdbthread.h (class thread_info) <displaced_step_state>: New
field.
(thread_step_over_chain_remove): New declaration.
(thread_step_over_chain_next): New declaration.
(thread_step_over_chain_length): New declaration.
* thread.c (thread_step_over_chain_remove): Make non-static.
(thread_step_over_chain_next): New.
(global_thread_step_over_chain_next): Use
thread_step_over_chain_next.
(thread_step_over_chain_length): New.
(global_thread_step_over_chain_enqueue): Add debug print.
(global_thread_step_over_chain_remove): Add debug print.
* infrun.h (get_displaced_step_copy_insn_closure_by_addr):
Remove.
* infrun.c (get_displaced_stepping_state): New.
(displaced_step_in_progress_any_inferior): Remove.
(displaced_step_in_progress_thread): Adjust.
(displaced_step_in_progress): Adjust.
(displaced_step_in_progress_any_thread): New.
(get_displaced_step_copy_insn_closure_by_addr): Remove.
(gdbarch_supports_displaced_stepping): Use
gdbarch_displaced_step_prepare_p.
(displaced_step_reset): Change parameter from inferior to
thread.
(displaced_step_prepare_throw): Implement using
gdbarch_displaced_step_prepare.
(write_memory_ptid): Move to displaced-step.c.
(displaced_step_restore): Remove.
(displaced_step_finish): Implement using
gdbarch_displaced_step_finish.
(start_step_over): Allow starting more than one displaced step.
(prepare_for_detach): Handle possibly multiple threads doing
displaced steps.
(handle_inferior_event): Handle possibility that fork event
happens while another thread displaced steps.
* linux-tdep.h (linux_displaced_step_prepare): New.
(linux_displaced_step_finish): New.
(linux_displaced_step_copy_insn_closure_by_addr): New.
(linux_displaced_step_restore_all_in_ptid): New.
(linux_init_abi): Add supports_displaced_step parameter.
* linux-tdep.c (struct linux_info) <disp_step_buf>: New field.
(linux_displaced_step_prepare): New.
(linux_displaced_step_finish): New.
(linux_displaced_step_copy_insn_closure_by_addr): New.
(linux_displaced_step_restore_all_in_ptid): New.
(linux_init_abi): Add supports_displaced_step parameter,
register displaced step methods if true.
(_initialize_linux_tdep): Register inferior_execd observer.
* amd64-linux-tdep.c (amd64_linux_init_abi_common): Add
supports_displaced_step parameter, adjust call to
linux_init_abi. Remove call to
set_gdbarch_displaced_step_location.
(amd64_linux_init_abi): Adjust call to
amd64_linux_init_abi_common.
(amd64_x32_linux_init_abi): Likewise.
* aarch64-linux-tdep.c (aarch64_linux_init_abi): Adjust call to
linux_init_abi. Remove call to
set_gdbarch_displaced_step_location.
* arm-linux-tdep.c (arm_linux_init_abi): Likewise.
* i386-linux-tdep.c (i386_linux_init_abi): Likewise.
* alpha-linux-tdep.c (alpha_linux_init_abi): Adjust call to
linux_init_abi.
* arc-linux-tdep.c (arc_linux_init_osabi): Likewise.
* bfin-linux-tdep.c (bfin_linux_init_abi): Likewise.
* cris-linux-tdep.c (cris_linux_init_abi): Likewise.
* csky-linux-tdep.c (csky_linux_init_abi): Likewise.
* frv-linux-tdep.c (frv_linux_init_abi): Likewise.
* hppa-linux-tdep.c (hppa_linux_init_abi): Likewise.
* ia64-linux-tdep.c (ia64_linux_init_abi): Likewise.
* m32r-linux-tdep.c (m32r_linux_init_abi): Likewise.
* m68k-linux-tdep.c (m68k_linux_init_abi): Likewise.
* microblaze-linux-tdep.c (microblaze_linux_init_abi): Likewise.
* mips-linux-tdep.c (mips_linux_init_abi): Likewise.
* mn10300-linux-tdep.c (am33_linux_init_osabi): Likewise.
* nios2-linux-tdep.c (nios2_linux_init_abi): Likewise.
* or1k-linux-tdep.c (or1k_linux_init_abi): Likewise.
* riscv-linux-tdep.c (riscv_linux_init_abi): Likewise.
* s390-linux-tdep.c (s390_linux_init_abi_any): Likewise.
* sh-linux-tdep.c (sh_linux_init_abi): Likewise.
* sparc-linux-tdep.c (sparc32_linux_init_abi): Likewise.
* sparc64-linux-tdep.c (sparc64_linux_init_abi): Likewise.
* tic6x-linux-tdep.c (tic6x_uclinux_init_abi): Likewise.
* tilegx-linux-tdep.c (tilegx_linux_init_abi): Likewise.
* xtensa-linux-tdep.c (xtensa_linux_init_abi): Likewise.
* ppc-linux-tdep.c (ppc_linux_init_abi): Adjust call to
linux_init_abi. Remove call to
set_gdbarch_displaced_step_location.
* arm-tdep.c (arm_pc_is_thumb): Call
gdbarch_displaced_step_copy_insn_closure_by_addr instead of
get_displaced_step_copy_insn_closure_by_addr.
* rs6000-aix-tdep.c (rs6000_aix_init_osabi): Adjust calls to
clear gdbarch methods.
* rs6000-tdep.c (struct ppc_inferior_data): New structure.
(get_ppc_per_inferior): New function.
(ppc_displaced_step_prepare): New function.
(ppc_displaced_step_finish): New function.
(ppc_displaced_step_restore_all_in_ptid): New function.
(rs6000_gdbarch_init): Register new gdbarch methods.
* s390-tdep.c (s390_gdbarch_init): Don't call
set_gdbarch_displaced_step_location, set new gdbarch methods.
gdb/testsuite/ChangeLog:
* gdb.arch/amd64-disp-step-avx.exp: Adjust pattern.
* gdb.threads/forking-threads-plus-breakpoint.exp: Likewise.
* gdb.threads/non-stop-fair-events.exp: Likewise.
Change-Id: I387cd235a442d0620ec43608fd3dc0097fcbf8c8
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Since we're going to introduce other "displaced step" functions and
another kind of displaced step closure, make it clear that this is the
return type of the gdbarch_displaced_step_copy_insn function.
gdb/ChangeLog:
* infrun.h (get_displaced_step_closure_by_addr): Rename to...
(get_displaced_step_copy_insn_closure_by_addr): ... this.
Update all users.
(displaced_step_closure): Rename to...
(displaced_step_copy_insn_closure): ... this. Update all users.
(displaced_step_closure_up): Rename to...
(displaced_step_copy_insn_closure_up). ... this. Update all
users.
(buf_displaced_step_closure): Rename to...
(buf_displaced_step_copy_insn_closure): ... this. Update all
users.
* infrun.c (get_displaced_step_closure_by_addr): Rename to...
(get_displaced_step_copy_insn_closure_by_addr): ... this.
Update all users.
* aarch64-tdep.c (aarch64_displaced_step_closure): Rename to...
(aarch64_displaced_step_copy_insn_closure): ... this. Update
all users.
* amd64-tdep.c (amd64_displaced_step_closure): Rename to...
(amd64_displaced_step_copy_insn_closure): ... this. Update all
users.
* arm-tdep.h (arm_displaced_step_closure): Rename to...
(arm_displaced_step_copy_insn_closure): ... this. Update all
users.
* i386-tdep.h (i386_displaced_step_closure): Rename to...
(i386_displaced_step_copy_insn_closure): ... this. Update all
users.
* rs6000-tdep.c (ppc_displaced_step_closure): Rename to...
(ppc_displaced_step_copy_insn_closure): ... this. Update all
users.
* s390-tdep.c (s390_displaced_step_closure): Rename to...
(s390_displaced_step_copy_insn_closure): ... this. Update all
users.
* gdbarch.h: Re-generate.
* gdbarch.c: Re-generate.
Change-Id: I11f56dbcd4c3532fb195a08ba93bccf1d12a03c8
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The "store on condition" instructions STOC, STOCG, and STOCFH are recorded
as if their instruction formats resembled that of STG. This is wrong,
usually resulting in "failed to record execution log" errors when trying
to record code with any of these instructions.
This patch fixes the recording of these instructions.
gdb/ChangeLog:
PR tdep/26916
* s390-tdep.c (s390_process_record): Fix recording of STOC, STOCG,
and STOCFH.
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Move all debug prints of the "displaced" category to use a new
displaced_debug_printf macro, like what was done for infrun and others
earlier.
The debug output for one displaced step one amd64 looks like:
[displaced] displaced_step_prepare_throw: stepping process 3367044 now
[displaced] displaced_step_prepare_throw: saved 0x555555555042: 1e fa 31 ed 49 89 d1 5e 48 89 e2 48 83 e4 f0 50
[displaced] amd64_displaced_step_copy_insn: copy 0x555555555131->0x555555555042: b8 00 00 00 00 5d c3 0f 1f 84 00 00 00 00 00 f3
[displaced] displaced_step_prepare_throw: displaced pc to 0x555555555042
[displaced] resume_1: run 0x555555555042: b8 00 00 00
[displaced] displaced_step_restore: restored process 3367044 0x555555555042
[displaced] amd64_displaced_step_fixup: fixup (0x555555555131, 0x555555555042), insn = 0xb8 0x00 ...
[displaced] amd64_displaced_step_fixup: relocated %rip from 0x555555555047 to 0x555555555136
On test case needed to be updated because it relied on the specific
formatting of the message.
gdb/ChangeLog:
* infrun.h (displaced_debug_printf): New macro. Replace
displaced debug prints throughout to use it.
(displaced_debug_printf_1): New declaration.
(displaced_step_dump_bytes): Return string, remove ui_file
parameter, update all callers.
* infrun.c (displaced_debug_printf_1): New function.
(displaced_step_dump_bytes): Return string, remove ui_file
parameter
gdb/testsuite/ChangeLog:
* gdb.arch/amd64-disp-step-avx.exp: Update displaced step debug
expected output.
Change-Id: Ie78837f56431f6f98378790ba1e6051337bf6533
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I noticed that the closure parameter of
gdbarch_displaced_step_hw_singlestep is never used by any
implementation of the method, so this patch removes it.
gdb/ChangeLog:
* gdbarch.sh (displaced_step_hw_singlestep): Remove closure
parameter.
* aarch64-tdep.c (aarch64_displaced_step_hw_singlestep):
Likewise.
* aarch64-tdep.h (aarch64_displaced_step_hw_singlestep):
Likewise.
* arch-utils.c (default_displaced_step_hw_singlestep):
Likewise.
* arch-utils.h (default_displaced_step_hw_singlestep):
Likewise.
* rs6000-tdep.c (ppc_displaced_step_hw_singlestep):
Likewise.
* s390-tdep.c (s390_displaced_step_hw_singlestep):
Likewise.
* gdbarch.c: Re-generate.
* gdbarch.h: Re-generate.
* infrun.c (resume_1): Adjust.
Change-Id: I7354f0b22afc2692ebff0cd700a462db8f389fc1
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Replace the int-used-as-a-bool with a bool.
gdb/ChangeLog:
* gdbarch.sh (displaced_step_hw_singlestep): Return bool.
* gdbarch.c: Re-generate.
* gdbarch.h: Re-generate.
* aarch64-tdep.c (aarch64_displaced_step_hw_singlestep): Return
bool.
* aarch64-tdep.h (aarch64_displaced_step_hw_singlestep):
Likewise.
* arch-utils.h (default_displaced_step_hw_singlestep): Likewise.
* arch-utils.c (default_displaced_step_hw_singlestep): Likewise.
* rs6000-tdep.c (ppc_displaced_step_hw_singlestep): Likewise.
* s390-tdep.c (s390_displaced_step_hw_singlestep): Likewise.
Change-Id: I76a78366dc5c0afb03f8f4bddf9f4e8d68fe3114
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While working on something else, I noticed that tdesc_data_cleanup
took a void* parameter. Looking more into this, I found that
tdesc_use_registers expected a transfer of ownership.
I think it's better to express this sort of thing via the type system,
when possible. This patch changes tdesc_data_alloc to return a unique
pointer, changes tdesc_use_registers to accept an rvalue reference,
and then adapts all the users.
Note that a deleter structure is introduced to avoid having to move
tdesc_arch_data to the header file.
2020-09-17 Tom Tromey <tromey@adacore.com>
* tic6x-tdep.c (tic6x_gdbarch_init): Update.
* target-descriptions.h (struct tdesc_arch_data_deleter): New.
(tdesc_arch_data_up): New typedef.
(tdesc_use_registers, tdesc_data_alloc): Update.
(tdesc_data_cleanup): Don't declare.
* target-descriptions.c (tdesc_data_alloc): Return a
tdesc_arch_data_up.
(tdesc_arch_data_deleter::operator()): Rename from
tdesc_data_cleanup. Change argument type.
(tdesc_use_registers): Change early_data to an rvalue reference.
(tdesc_use_registers): Don't use delete.
* sparc-tdep.c (sparc32_gdbarch_init): Update.
* s390-tdep.c (s390_gdbarch_init): Update.
* rx-tdep.c (rx_gdbarch_init): Update.
* rs6000-tdep.c (rs6000_gdbarch_init): Update.
* riscv-tdep.c (riscv_gdbarch_init): Update.
* or1k-tdep.c (or1k_gdbarch_init): Update.
* nios2-tdep.c (nios2_gdbarch_init): Update.
* nds32-tdep.c (nds32_gdbarch_init): Update.
* mips-tdep.c (mips_gdbarch_init): Update.
* microblaze-tdep.c (microblaze_gdbarch_init): Update.
* m68k-tdep.c (m68k_gdbarch_init): Update.
* i386-tdep.c (i386_gdbarch_init): Update.
* arm-tdep.c (arm_gdbarch_init): Update.
* arc-tdep.c (arc_tdesc_init): Update.
(arc_gdbarch_init): Update.
* aarch64-tdep.c (aarch64_gdbarch_init): Update.
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A later patch in this series will rewrite enum_flags fixing some API
holes. That would cause build failures around code using
type_instance_flags. Or rather, that should be using it, but wasn't.
This patch fixes it by using type_instance_flags throughout instead of
plain integers.
Note that we can't make the seemingly obvious change to struct
type::instance_flags:
- unsigned instance_flags : 9;
+ ENUM_BITFIELD (type_instance_flag_value) instance_flags : 9;
Because G++ complains then that 9 bits isn't sufficient for holding
all values of type_instance_flag_value.
So the patch adds an type::instance_flags() method, which takes care
of casting appropriately, and adds a separate type::set_instance_flags
method, following the pattern of the ongoing TYPE_XXX macro
elimination. This converts uses of TYPE_INSTANCE_FLAGS to
type::instance_flags() in the places where the code was already being
touched, but there are still many references to the
TYPE_INSTANCE_FLAGS macro left behind. Those could/should be fully
replaced at some point.
gdb/ChangeLog:
* avr-tdep.c (avr_address_class_type_flags): Return
type_instance_flags.
(avr_address_class_type_flags_to_name): Take a
type_instance_flags.
(avr_address_class_name_to_type_flags): Return bool and take a
type_instance_flags.
* d-lang.c (build_d_types): Use type::set_instance_flags.
* ft32-tdep.c (ft32_address_class_type_flags): Return
type_instance_flags.
(ft32_address_class_type_flags_to_name): Take a
type_instance_flags.
(ft32_address_class_name_to_type_flags): Return bool and take a
type_instance_flags.
(ft32_gdbarch_init): Use type::set_instance_flags.
* eval.c (fake_method::fake_method): Use type::set_instance_flags.
* gdbarch.h, gdbarch.c: Regenerate.
* gdbarch.sh (address_class_type_flags): Use type_instance_flags.
(address_class_name_to_type_flags): Use type_instance_flags and
bool.
* gdbtypes.c (address_space_name_to_int)
(address_space_int_to_name, make_qualified_type): Use
type_instance_flags.
(make_qualified_type): Use type_instance_flags and
type::set_instance_flags.
(make_type_with_address_space, make_cv_type, make_vector_type)
(check_typedef): Use type_instance_flags.
(recursive_dump_type): Cast type_instance_flags to unsigned for
printing.
(copy_type_recursive): Use type::set_instance_flags.
(gdbtypes_post_init): Use type::set_instance_flags.
* gdbtypes.h (struct type) <instance_flags>: Rename to ...
<m_instance_flags>: ... this.
<instance_flags, set_instance_flags>: New methods.
(TYPE_INSTANCE_FLAGS): Use the instance_flags method.
(SET_TYPE_INSTANCE_FLAGS): New.
(address_space_name_to_int, address_space_int_to_name)
(make_type_with_address_space): Pass flags using
type_instance_flags instead of int.
* stabsread.c (cleanup_undefined_types_noname): Use
type::set_instance_flags.
* s390-tdep.c (s390_address_class_type_flags): Return
type_instance_flags.
(s390_address_class_type_flags_to_name): Take a
type_instance_flags.
(s390_address_class_name_to_type_flags): Return bool and take a
type_instance_flags.
* type-stack.c (type_stack::follow_types): Use
type_instance_flags.
* dwarf2/read.c (read_tag_pointer_type): Use type_instance_flags.
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gdb/ChangeLog:
* gdbtypes.h (TYPE_VECTOR): Remove, replace all
uses with type::is_vector.
Change-Id: I1ac28755af44b1585c190553f9961288c8fb9137
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gdb/ChangeLog:
* gdbtypes.h (TYPE_VARARGS): Remove, replace all
uses with type::has_varargs.
Change-Id: Ieea4a64b4bfa4b8be643e68cb403081881133740
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|
gdb/ChangeLog:
* gdbtypes.h (TYPE_UNSIGNED): Remove, replace all uses with
type::is_unsigned.
Change-Id: I84f76f5cd44ff7294e421d317376a9e476bc8666
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When building gdb with CFLAGS/CXXFLAGS="-O2 -g -Wall", I see:
...
src/gdb/s390-tdep.c: In function 'void s390_displaced_step_fixup(gdbarch*, \
displaced_step_closure*, CORE_ADDR, CORE_ADDR, regcache*)':
src/gdb/s390-tdep.c:528:30: warning: 'r2' may be used uninitialized in this \
function [-Wmaybe-uninitialized]
528 | if (insn[0] == op_basr && r2 == 0)
| ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~
...
The problem is that the compiler is unaware that
'is_rr (insn, op_basr, &r1, &r2) == 1' ensures that 'insn[0] == op_basr':
...
if (is_rr (insn, op_basr, &r1, &r2)
|| is_rx (insn, op_bas, &r1, &d2, &x2, &b2))
{
/* Recompute saved return address in R1. */
regcache_cooked_write_unsigned (regs, S390_R0_REGNUM + r1,
amode | (from + insnlen));
/* Update PC iff the instruction doesn't actually branch. */
if (insn[0] == op_basr && r2 == 0)
regcache_write_pc (regs, from + insnlen);
}
...
Fix this by storing the result of the call, and using it instead of
'insn[0] ==op_basr'.
Build on x86_64-linux with --enable-targets=s390-suse-linux,s390x-suse-linux.
gdb/ChangeLog:
2020-07-29 Tom de Vries <tdevries@suse.de>
PR tdep/26280
* s390-tdep.c (s390_displaced_step_fixup): Fix Wmaybe-uninitialized.
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|
Remove the `FIELD_TYPE` macro, changing all the call sites to use
`field::type` directly.
gdb/ChangeLog:
* gdbtypes.h (FIELD_TYPE): Remove. Change all call sites
to use field::type instead.
Change-Id: I7673fedaa276e485189c87991a9043495da22ef5
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Replace all uses of it by type::field.
Note that since type::field returns a reference to the field, some spots
are used to assign the whole field structure. See ctfread.c, function
attach_fields_to_type, for example. This is the same as was happening
with the macro, so I don't think it's a problem, but if anybody sees a
really nicer way to do this, now could be a good time to implement it.
gdb/ChangeLog:
* gdbtypes.h (TYPE_FIELD): Remove. Replace all uses with
type::field.
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Remove `TYPE_NFIELDS`, changing all the call sites to use
`type::num_fields` directly. This is quite a big diff, but this was
mostly done using sed and coccinelle. A few call sites were done by
hand.
gdb/ChangeLog:
* gdbtypes.h (TYPE_NFIELDS): Remove. Change all cal sites to use
type::num_fields instead.
Change-Id: Ib73be4c36f9e770e0f729bac3b5257d7cb2f9591
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|
Remove TYPE_CODE, changing all the call sites to use type::code
directly. This is quite a big diff, but this was mostly done using sed
and coccinelle. A few call sites were done by hand.
gdb/ChangeLog:
* gdbtypes.h (TYPE_CODE): Remove. Change all call sites to use
type::code instead.
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Use an explicit conversion from unique_ptr<T> to
displaced_step_closure_up to avoid a compiler bug
with gcc-4.8.4:
../../binutils-gdb/gdb/amd64-tdep.c:1514:10: error: cannot bind
'std::unique_ptr<amd64_displaced_step_closure>' lvalue to
'std::unique_ptr<amd64_displaced_step_closure>&&'
gdb:
2020-02-18 Bernd Edlinger <bernd.edlinger@hotmail.de>
* aarch64-tdep.c (aarch64_displaced_step_copy_insn): Use an explicit
conversion.
* amd64-tdep.c (amd64_displaced_step_copy_insn): Likewise.
* arm-linux-tdep.c (arm_linux_displaced_step_copy_insn): Likewise.
* i386-tdep.c (i386_displaced_step_copy_insn): Likewise.
* rs6000-tdep.c (ppc_displaced_step_copy_insn): Likewise.
* s390-tdep.c (s390_displaced_step_copy_insn): Likewise.
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|
To help with readability, add the type displaced_step_closure_up, an
alias for std::unique_ptr<displaced_step_closure>, and use it throughout
the code base.
gdb/ChangeLog:
* aarch64-tdep.c (aarch64_displaced_step_copy_insn): Use
displaced_step_closure_up.
* aarch64-tdep.h (aarch64_displaced_step_copy_insn): Likewise.
(struct displaced_step_closure_up):
* amd64-tdep.c (amd64_displaced_step_copy_insn): Likewise.
* amd64-tdep.h (amd64_displaced_step_copy_insn): Likewise.
* arm-linux-tdep.c (arm_linux_displaced_step_copy_insn):
Likewise.
* gdbarch.sh (displaced_step_copy_insn): Likewise.
* gdbarch.c, gdbarch.h: Re-generate.
* i386-linux-tdep.c (i386_linux_displaced_step_copy_insn): Use
displaced_step_closure_up.
* i386-tdep.c (i386_displaced_step_copy_insn): Likewise.
* i386-tdep.h (i386_displaced_step_copy_insn): Likewise.
* infrun.h (displaced_step_closure_up): New type alias.
(struct displaced_step_inferior_state) <step_closure>: Change
type to displaced_step_closure_up.
* rs6000-tdep.c (ppc_displaced_step_copy_insn): Use
displaced_step_closure_up.
* s390-tdep.c (s390_displaced_step_copy_insn): Likewise.
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This callback dynamically allocates a specialized displaced_step_closure, and
gives the ownership of the object to its caller. So I think it would make
sense for the callback to return an std::unique_ptr, this is what this patch
implements.
gdb/ChangeLog:
* gdbarch.sh (displaced_step_copy_insn): Change return type to an
std::unique_ptr.
* gdbarch.c: Re-generate.
* gdbarch.h: Re-generate.
* infrun.c (displaced_step_prepare_throw): Adjust to std::unique_ptr
change.
* aarch64-tdep.c (aarch64_displaced_step_copy_insn): Change return
type to std::unique_ptr.
* aarch64-tdep.h (aarch64_displaced_step_copy_insn): Likewise.
* amd64-tdep.c (amd64_displaced_step_copy_insn): Likewise.
* amd64-tdep.h (amd64_displaced_step_copy_insn): Likewise.
* arm-linux-tdep.c (arm_linux_displaced_step_copy_insn): Likewise.
* i386-linux-tdep.c (i386_linux_displaced_step_copy_insn): Likewise.
* i386-tdep.c (i386_displaced_step_copy_insn): Likewise.
* i386-tdep.h (i386_displaced_step_copy_insn): Likewise.
* rs6000-tdep.c (ppc_displaced_step_copy_insn): Likewise.
* s390-tdep.c (s390_displaced_step_copy_insn): Likewise.
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