This patch is the next piece of work in my Large Watchpoint proposal,
https://discourse.llvm.org/t/rfc-large-watchpoint-support-in-lldb/72116
This patch breaks a user's watchpoint into one or more
WatchpointResources which reflect what the hardware registers can cover.
This means we can watch objects larger than 8 bytes, and we can watched
unaligned address ranges. On a typical 64-bit target with 4 watchpoint
registers you can watch 32 bytes of memory if the start address is
doubleword aligned.
Additionally, if the remote stub implements AArch64 MASK style
watchpoints (e.g. debugserver on Darwin), we can watch any power-of-2
size region of memory up to 2GB, aligned to that same size.
I updated the Watchpoint constructor and CommandObjectWatchpoint to
create a CompilerType of Array<UInt8> when the size of the watched
region is greater than pointer-size and we don't have a variable type to
use. For pointer-size and smaller, we can display the watched granule as
an integer value; for larger-than-pointer-size we will display as an
array of bytes.
I have `watchpoint list` now print the WatchpointResources used to
implement the watchpoint.
I added a WatchpointAlgorithm class which has a top-level static method
that takes an enum flag mask WatchpointHardwareFeature and a user
address and size, and returns a vector of WatchpointResources covering
the request. It does not take into account the number of watchpoint
registers the target has, or the number still available for use. Right
now there is only one algorithm, which monitors power-of-2 regions of
memory. For up to pointer-size, this is what Intel hardware supports.
AArch64 Byte Address Select watchpoints can watch any number of
contiguous bytes in a pointer-size memory granule, that is not currently
supported so if you ask to watch bytes 3-5, the algorithm will watch the
entire doubleword (8 bytes). The newly default "modify" style means we
will silently ignore modifications to bytes outside the watched range.
I've temporarily skipped TestLargeWatchpoint.py for all targets. It was
only run on Darwin when using the in-tree debugserver, which was a proxy
for "debugserver supports MASK watchpoints". I'll be adding the
aforementioned feature flag from the stub and enabling full mask
watchpoints when a debugserver with that feature is enabled, and
re-enable this test.
I added a new TestUnalignedLargeWatchpoint.py which only has one test
but it's a great one, watching a 22-byte range that is unaligned and
requires four 8-byte watchpoints to cover.
I also added a unit test, WatchpointAlgorithmsTests, which has a number
of simple tests against WatchpointAlgorithms::PowerOf2Watchpoints. I
think there's interesting possible different approaches to how we cover
these; I note in the unit test that a user requesting a watch on address
0x12e0 of 120 bytes will be covered by two watchpoints today, a
128-bytes at 0x1280 and at 0x1300. But it could be done with a 16-byte
watchpoint at 0x12e0 and a 128-byte at 0x1300, which would have fewer
false positives/private stops. As we try refining this one, it's helpful
to have a collection of tests to make sure things don't regress.
I tested this on arm64 macOS, (genuine) x86_64 macOS, and AArch64
Ubuntu. I have not modifed the Windows process plugins yet, I might try
that as a standalone patch, I'd be making the change blind, but the
necessary changes (see ProcessGDBRemote::EnableWatchpoint) are pretty
small so it might be obvious enough that I can change it and see what
the Windows CI thinks.
There isn't yet a packet (or a qSupported feature query) for the gdb
remote serial protocol stub to communicate its watchpoint capabilities
to lldb. I'll be doing that in a patch right after this is landed,
having debugserver advertise its capability of AArch64 MASK watchpoints,
and have ProcessGDBRemote add eWatchpointHardwareArmMASK to
WatchpointAlgorithms so we can watch larger than 32-byte requests on
Darwin.
I haven't yet tackled WatchpointResource *sharing* by multiple
Watchpoints. This is all part of the goal, especially when we may be
watching a larger memory range than the user requested, if they then add
another watchpoint next to their first request, it may be covered by the
same WatchpointResource (hardware watchpoint register). Also one "read"
watchpoint and one "write" watchpoint on the same memory granule need to
be handled, making the WatchpointResource cover all requests.
As WatchpointResources aren't shared among multiple Watchpoints yet,
there's no handling of running the conditions/commands/etc on multiple
Watchpoints when their shared WatchpointResource is hit. The goal beyond
"large watchpoint" is to unify (much more) the Watchpoint and Breakpoint
behavior and commands. I have a feeling I may be slowly chipping away at
this for a while.
Re-landing this patch after fixing two undefined behaviors in
WatchpointAlgorithms found by UBSan and by failures on different
CI bots.
rdar://108234227
In https://reviews.llvm.org/D136620 I changed debugserver to stop using
the kernel-provided functions
arm_thread_state64_get_{pc,lr,sp,fp} to postprocess those four registers
on aarch64 systems after we thread_get_state() them. The kernel stores
these four registers with signing internally, either from the inferior
process' actual signing, or its own.
When a program had crashed by doing an authenticated BL to an address
with improper signing, the inferior process would crash and that
improperly signed pc would be given to debugserver via thread_get_state.
debugserver would run that through arm_thread_state64_get_pc() and then
debugserver would crash when authenticating & stripping the value, on
newer Mac hardware.
To avoid debugserver crashing on a crashed inferior process, I switched
from using these system functions to strip the values, to simply
clearing the bits outright in debugserver.
However, lr is a special case where the inferior may have signed this
value (against the stack pointer value at the time). Or it may not yet
have any authentication bits, right after a BL. In the latter case, the
kernel will add its own auth bits for while it is stored inside the
kernel. In the case of a user lr value, we cannot authenticate it in
debugserver without knowing the sp value it was signed against (and the
way it is signed is not specified by the ABI) so an "improperly" signed
lr (whatever that means) won't cause debugserver to crash.
debugserver can thread_get_state the inferior's lr, run it through
arm_thread_state64_get_lr(), and get the actual signed 64-bit value that
the inferior process is using. And the specifics of how that lr is
signed may be important for debugging the process, instead of how I am
currently clearing the auth bits outright.
This patch reverts that change for lr only, and also adds a new logging
to debugserver specifically for the four sp/fp/lr/pc values that
thread_get_state hands to us, before we process them at all.
Add suport for MASK style watchpoints on AArch64 in debugserver
on Darwin systems, for watching power-of-2 sized memory ranges.
More work needed in lldb before this can be exposed to the user
(because they will often try watching memory ranges that are not
exactly power-of-2 in size/alignment) but this is the first part
of adding that capability.
Differential Revision: https://reviews.llvm.org/D149792
rdar://108233371
Refactor the debugserver watchpiont support in anticipating of
adding support for AArch64 MASK hardware watchpoints to watch
larger regions of memory. debugserver already had support for
handling a request to watch an unaligned region of memory up
to 8 bytes using Byte Address Select watchpoints - it would split
an unaligned watch request into two aligned doublewords that
could be watched with two hardware watchpoints using the BAS
specification.
This patch generalizes that code for properly aligning, and
possibly splitting, a watchpoint request into two hardware watchpoints
to handle any size request. And separates out the specifics
about BAS watchpoints into its own method, so a sibling method
for MASK watchpoints can be dropped in next.
Differential Revision: https://reviews.llvm.org/D149040
rdar://108233371
The arm64 register context on Darwin has the 29 general purpose
registers, then pc/sp/lr/fp with different field names depending
on compile-time flags. Instead of accessing beyond the end of
the uint64_t[29] array, and upsetting the sanitizers, access those
registers correctly with the correct name.
Fixes a test failure on the ASAN CI bot, currently being
skipped, in TestEarlyProcessLaunch.py.
Differential Revision: https://reviews.llvm.org/D140067
rdar://103359354
debugserver is currently using kernel supplied macros,
arm_thread_state64_get_{pc,fp,sp,lr} which can crash on an authorization
failure when the inferior has crashed with an invalid pc value, for
instance. debugserver needs to be resistant to crashing in this
scenario, and we're merely clearing the bits, so do it with a bit
mask operation instead.
Differential Revision: https://reviews.llvm.org/D136620
rdar://98073271
rdar://100663221
Report the correct register number (GENERIC_REGNUM_FLAGS) for cpsr. This
fixes TestLldbGdbServer.py on Apple Silicon.
Differential revision: https://reviews.llvm.org/D126076
The C headers are deprecated so as requested in D102845, this is replacing them
all with their (not deprecated) C++ equivalent.
Reviewed By: shafik
Differential Revision: https://reviews.llvm.org/D103084
This fixes the following two warnings in code that's only compiled on
arm64:
- warning: cast from 'const void *' to 'unsigned char *' drops const
qualifier [-Wcast-qual]
- warning: embedding a directive within macro arguments has undefined
behavior [-Wembedded-directive]
On x86_64, when you hit a __builtin_debugtrap instruction, you
can continue past this in the debugger. This patch has debugserver
recognize the specific instruction used for __builtin_debugtrap
and advance the pc past it, so that the user can continue execution
once they've hit one of these.
In the patch discussion, we were in agreement that it would be better
to have this knowledge up in lldb instead of depending on each
stub rewriting the pc behind the debugger's back, but that's a
larger scale change for another day.
<rdar://problem/65521634>
Differential revision: https://reviews.llvm.org/D91238
LLDB has a few different styles of header guards and they're not very
consistent because things get moved around or copy/pasted. This patch
unifies the header guards across LLDB and converts everything to match
LLVM's style.
Differential revision: https://reviews.llvm.org/D74743
The changes are minor; primarily debugserver needs to go through
accessor functions/macros when changing pc/fp/sp/lr, and debugserver
needs to clear any existing pointer auth bits from values in two
cases. debugserver can fetch the number of bits used for addressing
from a sysctl, and will include that in the qHostInfo reply. Update
qHostInfo documentation to document it.
debugserver had been using an instruction that would work
for armv7 or aarch64 processes, but we don't have armv7 code
running on arm64 devices any more so this is unnecessary.
<rdar://problem/56133118>
llvm-svn: 374264
Adrian's changes to support Catalyst processes and my
changes to support debugserver running on an arm64_32
device (Apple Watch Series 4, which uses an IPL32 model
on arm64 cpus).
llvm-svn: 368118
A lot of comments in LLDB are surrounded by an ASCII line to delimit the
begging and end of the comment.
Its use is not really consistent across the code base, sometimes the
lines are longer, sometimes they are shorter and sometimes they are
omitted. Furthermore, it looks kind of weird with the 80 column limit,
where the comment actually extends past the line, but not by much.
Furthermore, when /// is used for Doxygen comments, it looks
particularly odd. And when // is used, it incorrectly gives the
impression that it's actually a Doxygen comment.
I assume these lines were added to improve distinguishing between
comments and code. However, given that todays editors and IDEs do a
great job at highlighting comments, I think it's worth to drop this for
the sake of consistency. The alternative is fixing all the
inconsistencies, which would create a lot more churn.
Differential revision: https://reviews.llvm.org/D60508
llvm-svn: 358135
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
This renames the LLDB error class to Status, as discussed
on the lldb-dev mailing list.
A change of this magnitude cannot easily be done without
find and replace, but that has potential to catch unwanted
occurrences of common strings such as "Error". Every effort
was made to find all the obvious things such as the word "Error"
appearing in a string, etc, but it's possible there are still
some lingering occurences left around. Hopefully nothing too
serious.
llvm-svn: 302872
*** to conform to clang-format’s LLVM style. This kind of mass change has
*** two obvious implications:
Firstly, merging this particular commit into a downstream fork may be a huge
effort. Alternatively, it may be worth merging all changes up to this commit,
performing the same reformatting operation locally, and then discarding the
merge for this particular commit. The commands used to accomplish this
reformatting were as follows (with current working directory as the root of
the repository):
find . \( -iname "*.c" -or -iname "*.cpp" -or -iname "*.h" -or -iname "*.mm" \) -exec clang-format -i {} +
find . -iname "*.py" -exec autopep8 --in-place --aggressive --aggressive {} + ;
The version of clang-format used was 3.9.0, and autopep8 was 1.2.4.
Secondly, “blame” style tools will generally point to this commit instead of
a meaningful prior commit. There are alternatives available that will attempt
to look through this change and find the appropriate prior commit. YMMV.
llvm-svn: 280751
debugserver to match. "gcc" is now "ehframe" and "gdb" is now
"debugserver". Because this is debugserver, what we call the Process
Plugin register numbers up in lldb are the debugserver register
numbers down here - they are the register numbers that debugserver
will use to refer to these registers over the gdb-remote protocol.
debugserver was already reporting the registers with the key
"ehframe"; this change is just cleaning up the internal variable
names to match.
llvm-svn: 247751
Summary:
This replaces (void)x; usages where they x was subsequently
involved in an assertion with this macro to make the
intent more clear.
Reviewers: clayborg
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D11451
llvm-svn: 243074
Replace adhoc inline implementation of llvm::array_lengthof in favour of the
implementation in LLVM. This is simply a cleanup change, no functional change
intended.
llvm-svn: 211868
These changes were written by Greg Clayton, Jim Ingham, Jason Molenda.
It builds cleanly against TOT llvm with xcodebuild. I updated the
cmake files by visual inspection but did not try a build. I haven't
built these sources on any non-Mac platforms - I don't think this
patch adds any code that requires darwin, but please let me know if
I missed something.
In debugserver, MachProcess.cpp and MachTask.cpp were renamed to
MachProcess.mm and MachTask.mm as they picked up some new Objective-C
code needed to launch processes when running on iOS.
llvm-svn: 205113
