5404 Commits

Author SHA1 Message Date
Jim Ingham
69529286ce Add a test for top-level expressions using "expr --top-level".
This was broken for a while even though the Python version
continued to work.  This adds a test so it doesn't regress.
2021-07-27 13:38:09 -07:00
Jim Ingham
0018c7123b Fix "break delete --disabled" with no arguments.
The code that figured out which breakpoints to delete was supposed
to set the result status if it found breakpoints, and then the code
that actually deleted them checked that the result's status was set.

The code for "break delete --disabled" failed to set the status if
no "protected" breakpoints were provided.  This was a confusing way
to implement this, so I reworked it with early returns so it was less
error prone, and added a test case for the no arguments case.

Differential Revision: https://reviews.llvm.org/D106623
2021-07-27 13:38:09 -07:00
Raphael Isemann
43e45f0ec9 [lldb] Wait in TestGuiBasicDebug for the interface to open before quitting the welcome screen
Speculative fix for the failing lldb-aarch64-ubuntu bot.
2021-07-27 13:58:49 +02:00
David Spickett
7d27230de3 [lldb][AArch64] Add memory tag writing to lldb-server
This is implemented using the QMemTags packet, as specified
by GDB in:
https://sourceware.org/gdb/current/onlinedocs/gdb/General-Query-Packets.html#General-Query-Packets

(recall that qMemTags was previously added to read tags)

On receipt of a valid packet lldb-server will:
* align the given address and length to granules
  (most of the time lldb will have already done this
  but the specification doesn't guarantee it)
* Repeat the supplied tags as many times as needed to cover
  the range. (if tags > range we just use as many as needed)
* Call ptrace POKEMTETAGS to write the tags.

The ptrace step will loop just like the tag read does,
until all tags are written or we get an error.
Meaning that if ptrace succeeds it could be a partial write.
So we call it again and if we then get an error, return an error to
lldb.

We are not going to attempt to restore tags after a partial
write followed by an error. This matches the behaviour of the
existing memory writes.

The lldb-server tests have been extended to include read and
write in the same test file. With some updated function names
since "qMemTags" vs "QMemTags" isn't very clear when they're
next to each other.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D105180
2021-07-27 12:02:17 +01:00
Amy Huang
1a3bf2953a [DebugInfo] Switch to using constructor homing (-debug-info-kind=constructor) by default when debug info is enabled
Constructor homing reduces the amount of class type info that is emitted
by emitting conmplete type info for a class only when a constructor for
that class is emitted.

This will mainly reduce the amount of duplicate debug info in object
files. In Chrome enabling ctor homing decreased total build directory sizes
by about 30%.

It's also expected that some class types (such as unused classes)
will no longer be emitted in the debug info. This is fine, since we wouldn't
expect to need these types when debugging.

In some cases (e.g. libc++, https://reviews.llvm.org/D98750), classes
are used without calling the constructor. Since this is technically
undefined behavior, enabling constructor homing should be fine.
However Clang now has an attribute
`__attribute__((standalone_debug))` that can be used on classes to
ignore ctor homing.

Bug: https://bugs.llvm.org/show_bug.cgi?id=46537

Differential Revision: https://reviews.llvm.org/D106084
2021-07-26 17:24:42 -07:00
Omar Emara
fed25ddc1c [LLDB][GUI] Expand selected thread tree item by default
This patch expands the tree item that corresponds to the selected thread
by default in the Threads window. Additionally, the tree root item is
always expanded, which is the process in the Threads window.

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D100243
2021-07-26 14:20:50 -07:00
Fangrui Song
b71b25008f [test] Fix PayloadString: in lldb tests 2021-07-26 10:00:05 -07:00
Walter Erquinigo
ef8c6849a2 [source maps] fix source mapping when there are multiple matching rules
D104406 introduced an error in which, if there are multiple matchings rules for a given path, lldb was only checking for the validity in the filesystem of the first match instead of looking exhaustively one by one until a valid file is found.

Besides that, a call to consume_front was being done incorrectly, as it was modifying the input, which renders subsequent matches incorrect.

I added a test that checks for both cases.

Differential Revision: https://reviews.llvm.org/D106723
2021-07-23 17:53:12 -07:00
Jim Ingham
bcce8e0fcc Fix the logic so stop-hooks get run after a breakpoint that ran an expression
Code was added to Target::RunStopHook to make sure that we don't run stop hooks when
you stop after an expression evaluation. But the way it was done was to check that we
hadn't run an expression since the last natural stop. That failed in the case where you
stopped for a breakpoint which had run an expression, because the stop-hooks get run
after the breakpoint actions, and so by the time we got to running the stop-hooks,
we had already run a user expression.

I fixed this by adding a target ivar tracking the last natural stop ID at which we had
run a stop-hook. Then we keep track of this and make sure we run the stop-hooks only
once per natural stop.

Differential Revision: https://reviews.llvm.org/D106514
2021-07-22 15:06:41 -07:00
Raphael Isemann
3d9a9fa691 [lldb] Remove a wrong assert in TestStructTypes that checks that empty structs in C always have size 0
D105471 fixes the way we assign sizes to empty structs in C mode. Instead of
just giving them a size 0, we instead use the size we get from DWARF if possible.

After landing D105471 the TestStructTypes test started failing on Windows. The
tests checked that the size of an empty C struct is 0 while the size LLDB now
reports is 4 bytes. It turns out that 4 bytes are the actual size Clang is using
for C structs with the MicrosoftRecordLayoutBuilder. The commit that introduced
that behaviour is 00a061dccc6671c96412d7b28ab2012963208579.

This patch removes that specific check from TestStructTypes. Note that D105471
added a series of tests that already cover this case (and the added checks
automatically adjust to whatever size the target compiler chooses for empty
structs).
2021-07-22 16:56:50 +02:00
Raphael Isemann
eb61ffbcb2 [lldb] Fix TestCompletion by using SIGPIPE instead of SIGINT as test signal
The test I added in commit 078003482e90ff5c7ba047a3d3152f0b0c392b31 was using
SIGINT for testing the tab completion. The idea is to have a signal that only
has one possible completion and I ended up picking SIGIN -> SIGINT for the test.
However on non-Linux systems there is SIGINFO which is a valid completion for
`SIGIN' and so the test fails there.

This replaces SIGIN -> SIGINT with SIGPIP -> SIGPIPE completion which according
to LLDB's signal list in Host.cpp is the only valid completion.
2021-07-22 15:35:28 +02:00
Med Ismail Bennani
312b43da05 [lldb/Plugins] Add ScriptedProcess Process Plugin
This patch introduces Scripted Processes to lldb.

The goal, here, is to be able to attach in the debugger to fake processes
that are backed by script files (in Python, Lua, Swift, etc ...) and
inspect them statically.

Scripted Processes can be used in cooperative multithreading environments
like the XNU Kernel or other real-time operating systems, but it can
also help us improve the debugger testing infrastructure by writting
synthetic tests that simulates hard-to-reproduce process/thread states.

Although ScriptedProcess is not feature-complete at the moment, it has
basic execution capabilities and will improve in the following patches.

rdar://65508855

Differential Revision: https://reviews.llvm.org/D100384

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-07-22 14:47:33 +02:00
Raphael Isemann
078003482e [lldb] Fix that process signal completion always returns all signals
`CompletionRequest::AddCompletion` adds the given string as completion of the
current command token. `CompletionRequest::TryCompleteCurrentArg` only adds it
if the current token is a prefix of the given string. We're using
`AddCompletion` for the `process signal` handler which means that `process
signal SIGIN` doesn't get uniquely completed to `process signal SIGINT` as we
unconditionally add all other signals (such as `SIGABRT`) as possible
completions.

By using `TryCompleteCurrentArg` we actually do the proper filtering which will
only add `SIGINT` (as that's the only signal with the prefix 'SIGIN' in the
example above).

Reviewed By: mib

Differential Revision: https://reviews.llvm.org/D105028
2021-07-22 13:51:21 +02:00
Raphael Isemann
67c588c481 [lldb] Generalize empty record size computation to avoid giving empty C++ structs a size of 0
C doesn't allow empty structs but Clang/GCC support them and give them a size of 0.

LLDB implements this by checking the tag kind and if it's `DW_TAG_structure_type` then
we give it a size of 0 via an empty external RecordLayout. This is done because our
internal TypeSystem is always in C++ mode (which means we would give them a size
of 1).

The current check for when we have this special case is currently too lax as types with
`DW_TAG_structure_type` can also occur in C++ with types defined using the `struct`
keyword. This means that in a C++ program with `struct Empty{};`, LLDB would return
`0` for `sizeof(Empty)` even though the correct size is 1.

This patch removes this special case and replaces it with a generic approach that just
assigns empty structs the byte_size as specified in DWARF. The GCC/Clang special
case is handles as they both emit an explicit `DW_AT_byte_size` of 0. And if another
compiler decides to use a different byte size for this case then this should also be
handled by the same code as long as that information is provided via `DW_AT_byte_size`.

Reviewed By: werat, shafik

Differential Revision: https://reviews.llvm.org/D105471
2021-07-22 13:30:48 +02:00
Jason Molenda
cdc6f8d728 Read and write a LC_NOTE "addrable bits" for addressing mask
This patch adds code to process save-core for Mach-O files which
embeds an "addrable bits" LC_NOTE when the process is using a
code address mask (e.g. AArch64 v8.3 with ptrauth aka arm64e).
Add code to ObjectFileMachO to read that LC_NOTE from corefiles,
and ProcessMachCore to set the process masks based on it when reading
a corefile back in.

Also have "process status --verbose" print the current address masks
that lldb is using internally to strip ptrauth bits off of addresses.

Differential Revision: https://reviews.llvm.org/D106348
rdar://68630113
2021-07-22 01:06:44 -07:00
Walter Erquinigo
345ace026b [trace] [intel pt] Create a "thread trace dump stats" command
When the user types that command 'thread trace dump info' and there's a running Trace session in LLDB, a raw trace in bytes should be printed; the command 'thread trace dump info all' should print the info for all the threads.

Original Author: hanbingwang

Reviewed By: clayborg, wallace

Differential Revision: https://reviews.llvm.org/D105717
2021-07-21 09:50:15 -07:00
Walter Erquinigo
04195843ef [intel pt] Add TSC timestamps
Differential Revision: https://reviews.llvm.org/D106328
2021-07-20 16:29:17 -07:00
Jason Molenda
b2e25572d2 Remove the DarwinLog functionality from debguserver
Remove the DarwinLog and qStructuredDataPlugins support
from debugserver.  The DarwinLog plugin was never debugged
fully and made reliable, and the underlying private APIs
it uses have migrated since 2016 so none of them exist
any longer.

Differential Revision: https://reviews.llvm.org/D106324
rdar://75073283
2021-07-20 00:36:56 -07:00
Walter Erquinigo
b0aa70761b [trace][intel pt] Implement the Intel PT cursor
D104422 added the interface for TraceCursor, which is the main way to traverse instructions in a trace. This diff implements the corresponding cursor class for Intel PT and deletes the now obsolete code.

Besides that, the logic for the "thread trace dump instructions" was adapted to use this cursor (pretty much I ended up moving code from Trace.cpp to TraceCursor.cpp). The command by default traverses the instructions backwards, and if the user passes --forwards, then it's not forwards. More information about that is in the Options.td file.

Regarding the Intel PT cursor. All Intel PT cursors for the same thread share the same DecodedThread instance. I'm not yet implementing lazy decoding because we don't need it. That'll be for later. For the time being, the entire thread trace is decoded when the first cursor for that thread is requested.

Differential Revision: https://reviews.llvm.org/D105531
2021-07-16 16:47:43 -07:00
Peter S. Housel
2e7ec447cc [lldb] Add AllocateMemory/DeallocateMemory to the SBProcess API
This change adds AllocateMemory and DeallocateMemory methods to the SBProcess
API, so that clients can allocate and deallocate memory blocks within the
process being debugged (for storing JIT-compiled code or other uses).

(I am developing a debugger + REPL using the API; it will need to store
JIT-compiled code within the target.)

Reviewed By: clayborg, jingham

Differential Revision: https://reviews.llvm.org/D105389
2021-07-16 00:45:22 +02:00
Jim Ingham
379f24ffde Revert "Revert "Reset the wakeup timeout when we re-enter the continue wait.""
This reverts commit 82a38837150099288a1262391ef43e1fd69ffde4.

The original version had a copy-paste error: using the Interrupt timeout
for the ResumeSynchronous wait, which is clearly wrong.  This error would
have been evident with real use, but the interrupt is long enough that it
only caused one testsuite failure (in the Swift fork).

Anyway, I found that mistake and fixed it and checked all the other places
where I had to plumb through a timeout, and added a test with a short
interrupt timeout stepping over a function that takes 3x the interrupt timeout
to complete, so that should detect a similar mistake in the future.
2021-07-12 14:20:49 -07:00
Muhammad Omair Javaid
10f5e08a71 [LLDB] Testsuite: Add helper to check for AArch64 target
This patch adds a helper function to test target architecture is
AArch64 or not. This also tightens isAArch64* helpers by adding an
extra architecture check.

Reviewed By: DavidSpickett

Differential Revision: https://reviews.llvm.org/D105483
2021-07-12 14:21:45 +05:00
Muhammad Omair Javaid
7c7447e344 [LLDB] Only build TestWatchTaggedAddress.py on aarch64 PAC targets
This patch fixes buildbot failures caused by TestWatchTaggedAddress.py

Differential Revision: https://reviews.llvm.org/D101361
2021-07-12 08:42:24 +05:00
Muhammad Omair Javaid
5e6aabd48e Support AArch64/Linux watchpoint on tagged addresses
AArch64 architecture support virtual addresses with some of the top bits ignored.
These ignored bits can host memory tags or bit masks that can serve to check for
authentication of address integrity. We need to clear away the top ignored bits
from watchpoint address to reliably hit and set watchpoints on addresses
containing tags or masks in their top bits.

This patch adds support to watch tagged addresses on AArch64/Linux.

Reviewed By: DavidSpickett

Differential Revision: https://reviews.llvm.org/D101361
2021-07-12 07:39:26 +05:00
Jonas Devlieghere
3338819b08 [lldb] Drop REQUIRES where redundant because of lit.local.cfg 2021-07-09 13:25:10 -07:00
Jonas Devlieghere
488fcea3b5 [lldb] Use custom script instead of lldb.macosx.crashlog in test
I'm not entirely sure this is the problem, but the Windows bot doesn't
seem to like this test. Let's do something similar to
command_import.test which doesn't have that issue.
2021-07-09 12:42:11 -07:00
Jonas Devlieghere
f951735395 [lldb] Add the ability to silently import scripted commands
Add the ability to silence command script import. The motivation for
this change is being able to add command script import -s
lldb.macosx.crashlog to your ~/.lldbinit without it printing the
following message at the beginning of every debug session.

  "malloc_info", "ptr_refs", "cstr_refs", "find_variable", and
  "objc_refs" commands have been installed, use the "--help" options on
  these commands for detailed help.

In addition to forwarding the silent option to LoadScriptingModule, this
also changes ScriptInterpreterPythonImpl::ExecuteOneLineWithReturn and
ScriptInterpreterPythonImpl::ExecuteMultipleLines to honor the enable IO
option in ExecuteScriptOptions, which until now was ignored.

Note that IO is only enabled (or disabled) at the start of a session,
and for this particular use case, that's done when taking the Python
lock in LoadScriptingModule, which means that the changes to these two
functions are not strictly necessary, but (IMO) desirable nonetheless.

Differential revision: https://reviews.llvm.org/D105327
2021-07-09 10:05:39 -07:00
Siger Yang
e81ba28313 [lldb/lua] Add scripted watchpoints for Lua
Add support for Lua scripted watchpoints, with basic tests.

Differential Revision: https://reviews.llvm.org/D105034
2021-07-07 14:51:02 -03:00
Walter Erquinigo
d4cb286b05 [NFC][lldb-vscode] Fix launch test
Using br for creating breakpoints fails if there are other commands that
start with br.
2021-07-07 10:01:19 -07:00
Jonas Devlieghere
6b0d266036 Revert "Create synthetic symbol names on demand to improve memory consumption and startup times."
This reverts commit c8164d0276b97679e80db01adc860271ab4a5d11 and
43f6dad2344247976d5777f56a1fc29e39c6c717 because it breaks
TestDyldTrieSymbols.py on GreenDragon.
2021-07-02 16:21:47 -07:00
Med Ismail Bennani
707bda6e6c [lldb/test] Fix failure caused by synthetic symbol name refactoring
This patch fixes a failure in `TestFunctionStarts.py` that appeared
following a change of implementation for synthetic symbol names:

https://reviews.llvm.org/D105160

The failure is caused because the previously mentioned patch removes the
object file basename from the generated synthetic symbol names to allow
them to be shared in the constant string pool.

Hence, that last check is not necessary anymore.

rdar://80092322

Differential Revision: https://reviews.llvm.org/D105366

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-07-02 22:26:30 +02:00
Michał Górny
4d2503cd54 [lldb] [test] Add missing category to test_detach_current 2021-07-02 11:44:41 +02:00
Michał Górny
b7c140335b [lldb] [gdb-remote server] Support selecting process via Hg
Support using the extended thread-id syntax with Hg packet to select
a subprocess.  This makes it possible to start providing support for
running some of the debugger packets against another subprocesses.

Differential Revision: https://reviews.llvm.org/D100261
2021-07-02 10:23:11 +02:00
Greg Clayton
c8164d0276 Create synthetic symbol names on demand to improve memory consumption and startup times.
This fix was created after profiling the target creation of a large C/C++/ObjC application that contained almost 4,000,000 redacted symbol names. The symbol table parsing code was creating names for each of these synthetic symbols and adding them to the name indexes. The code was also adding the object file basename to the end of the symbol name which doesn't allow symbols from different shared libraries to share the names in the constant string pool.

Prior to this fix this was creating 180MB of "___lldb_unnamed_symbol" symbol names and was taking a long time to generate each name, add them to the string pool and then add each of these names to the name index.

This patch fixes the issue by:
- not adding a name to synthetic symbols at creation time, and allows name to be dynamically generated when accessed
- doesn't add synthetic symbol names to the name indexes, but catches this special case as name lookup time. Users won't typically set breakpoints or lookup these synthetic names, but support was added to do the lookup in case it does happen
- removes the object file baseanme from the generated names to allow the names to be shared in the constant string pool

Prior to this fix the startup times for a large application was:
12.5 seconds (cold file caches)
8.5 seconds (warm file caches)

After this fix:
9.7 seconds (cold file caches)
5.7 seconds (warm file caches)

The names of the symbols are auto generated by appending the symbol's UserID to the end of the "___lldb_unnamed_symbol" string and is only done when the name is requested from a synthetic symbol if it has no name.

Differential Revision: https://reviews.llvm.org/D105160
2021-06-29 17:44:33 -07:00
Stella Stamenova
c8a9c78e17 [lldb] Fix debug_loc.s which was broken after https://reviews.llvm.org/D103502
An empty location is now printed as <empty>
2021-06-29 13:54:48 -07:00
Stella Stamenova
9952d591cc [lldb] Fix globals-bss.cpp which was broken in https://reviews.llvm.org/D105055
-S replaced -s, so the test needs to be updated to use the new option
2021-06-29 13:39:18 -07:00
Stella Stamenova
bb2cfca2f3 Revert D104488 and friends since it broke the windows bot
Reverts commits:
"Fix failing tests after https://reviews.llvm.org/D104488."
"Fix buildbot failure after https://reviews.llvm.org/D104488."
"Create synthetic symbol names on demand to improve memory consumption and startup times."

This series of commits broke the windows lldb bot and then failed to fix all of the failing tests.
2021-06-29 12:58:55 -07:00
Raphael Isemann
c00032321a [lldb] Skip TestPairFromStdModule for now
I didn't get around to fix this change and the original commit itself seems
fine, so this looks like an existing LLDB/Clang bug that was just uncovered
by this change. Skipping while I'm investigating.
2021-06-29 19:01:11 +02:00
Med Ismail Bennani
d6b64612bd [lldb/Interpreter] Fix session-save-on-quit when using ^D
Previously, when `interpreter.save-session-on-quit` was enabled, lldb
would save the session transcript only when running the `quit` command.

This patch changes that so the transcripts are saved when the debugger
object is destroyed if the setting is enabled.

rdar://72902650

Differential Revision: https://reviews.llvm.org/D105038

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-06-29 10:54:29 +02:00
Med Ismail Bennani
fe1874dd2d [lldb/Interpreter] Add setting to set session transcript save directory
This patch introduces a new interpreter setting
`interpreter.save-session-directory` so the user can specify a directory
where the session transcripts will be saved.

If not set, the session transcript are saved on a temporary file.

rdar://72902842

Differential Revision: https://reviews.llvm.org/D105030

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-06-29 10:54:29 +02:00
Greg Clayton
42c05ed8be Fix failing tests after https://reviews.llvm.org/D104488.
Synthetic names no longer have the shared library name appended to the end.
2021-06-28 19:59:24 -07:00
Jim Ingham
4eabb12057 Add support for the NSMutableDictionary variant: "__NSFrozenDictionaryM"
This was an oversight of the commit: bb93483c119b92c1ec2b7a58505e21b9dce6a333 that
added support for the Frozen variants.  Also added a test case for the way that
currently produces one of these variants (a copy).
2021-06-25 14:59:26 -07:00
Raphael Isemann
c3549d4d7a [lldb] Skip TestDataFormatterSynthVal.py with GCC as the test compiler 2021-06-25 11:48:12 +02:00
Raphael Isemann
0adc66ff83 [lldb] Skip libstdc++ tests failing with GCC
Tracked in llvm.org/pr50861

These tests fail with all GCC versions I tested (8.5, 9.4, 10.3, 11.1).
2021-06-25 11:45:59 +02:00
Raphael Isemann
487ac0b3ee [lldb] Skip tests failing with GCC due to LLDB not being able to call constructors
Tracked in llvm.org/pr50814

These tests fail with all GCC versions I tested (8.5, 9.4, 10.3, 11.1).
2021-06-25 11:33:09 +02:00
David Spickett
64f98aae40 [lldb] Fix memory tag unsupported test
This corrects the test added in
31f9960c38529ce805edf9764535eb0ce188cadf
and temporarily patched in
3b4aad1186e8e8e6f6c7887cb5e8d9bfd7d3ce2f.

This test checks that the memory tag read
command errors when you use it on a platform
without memory tagging.
(which is why we skip the test if you actually
have MTE)

The problem with this test is that there's
two levels of unsupported each with it's own
specific error.

On anything that isn't AArch64, there's no
tagging extension we support. So you're told
that that is the case. As in "this won't ever work".

When you're on AArch64 we know that MTE could
be present on the remote and when we find that it
isn't, we tell you that instead.

Expect a different error message on AArch64 to fix
the test.
2021-06-25 08:57:05 +00:00
Muhammad Omair Javaid
975af861f3 Disable TestAArch64UnwindPAC.py for non PAC targets
TestAArch64UnwindPAC.py started failing on LLDB buildbot as underlying
hardware does not support PAC. This patch skips this test for targets
which do not support PAC feature.
2021-06-24 22:50:36 +00:00
Muhammad Omair Javaid
3b4aad1186 Fix typo in TestMemoryTag.py
TestMemoryTag.py should fail if underlying target doesnt support MTE.

Differential Revision: https://reviews.llvm.org/D97285
2021-06-24 22:19:51 +00:00
David Spickett
31f9960c38 [lldb][AArch64] Add "memory tag read" command
This new command looks much like "memory read"
and mirrors its basic behaviour.

(lldb) memory tag read new_buf_ptr new_buf_ptr+32
Logical tag: 0x9
Allocation tags:
[0x900fffff7ffa000, 0x900fffff7ffa010): 0x9
[0x900fffff7ffa010, 0x900fffff7ffa020): 0x0

Important proprties:
* The end address is optional and defaults to reading
  1 tag if ommitted
* It is an error to try to read tags if the architecture
  or process doesn't support it, or if the range asked
  for is not tagged.
* It is an error to read an inverted range (end < begin)
  (logical tags are removed for this check so you can
  pass tagged addresses here)
* The range will be expanded to fit the tagging granule,
  so you can get more tags than simply (end-begin)/granule size.
  Whatever you get back will always cover the original range.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D97285
2021-06-24 17:35:45 +01:00
David Spickett
da2e614f56 [lldb][AArch64] Add memory tag reading to lldb-server
This adds memory tag reading using the new "qMemTags"
packet and ptrace on AArch64 Linux.

This new packet is following the one used by GDB.
(https://sourceware.org/gdb/current/onlinedocs/gdb/General-Query-Packets.html)

On AArch64 Linux we use ptrace's PEEKMTETAGS to read
tags and we assume that lldb has already checked that the
memory region actually has tagging enabled.

We do not assume that lldb has expanded the requested range
to granules and expand it again to be sure.
(although lldb will be sending aligned ranges because it happens
to need them client side anyway)
Also we don't assume untagged addresses. So for AArch64 we'll
remove the top byte before using them. (the top byte includes
MTE and other non address data)

To do the ptrace read NativeProcessLinux will ask the native
register context for a memory tag manager based on the
type in the packet. This also gives you the ptrace numbers you need.
(it's called a register context but it also has non register data,
so it saves adding another per platform sub class)

The only supported platform for this is AArch64 Linux and the only
supported tag type is MTE allocation tags. Anything else will
error.

Ptrace can return a partial result but for lldb-server we will
be treating that as an error. To succeed we need to get all the tags
we expect.

(Note that the protocol leaves room for logical tags to be
read via qMemTags but this is not going to be implemented for lldb
at this time.)

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D95601
2021-06-24 17:02:55 +01:00