Commit Graph

172 Commits

Author SHA1 Message Date
Pavel Labath 8d1de7b34a [lldb/gdb-server] Better reporting of launch errors
Use our "rich error" facility to propagate error reported by the stub to
the user. lldb-server reports rich launch errors as of D133352.

To make this easier to implement, and reduce code duplication, I have
moved the vRun/A/qLaunchSuccess handling into a single
GDBRemoteCommunicationClient function.

Differential Revision: https://reviews.llvm.org/D134754
2022-10-06 17:18:51 +02:00
Jonas Devlieghere 70599d7027
[lldb] Remove LLDB reproducers
This patch removes the remaining reproducer code. The SBReproducer class
remains for ABI stability but is just an empty shell. This completes the
removal process outlined on the mailing list [1].

[1] https://lists.llvm.org/pipermail/lldb-dev/2021-September/017045.html
2022-09-19 14:43:31 -07:00
Michał Górny 2f50883c13 [lldb] [gdb-remote] Include PID in vCont packets if multiprocess
Try to always send vCont packets and include the PID in them if running
multiprocess.  This is necessary to ensure that with the upcoming full
multiprocess support always resumes the correct process without having
to resort to the legacy Hc packets.

Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D131758
2022-08-20 08:21:32 +02:00
Michael Buch 5517401f93 Revert "[lldb] [gdb-remote] Include PID in vCont packets if multiprocess"
This reverts commit ccb9d4d4ad.

https://reviews.llvm.org/D131758

Differential Revision: https://reviews.llvm.org/D132250
2022-08-19 18:05:41 +01:00
Michał Górny ccb9d4d4ad [lldb] [gdb-remote] Include PID in vCont packets if multiprocess
Try to always send vCont packets and include the PID in them if running
multiprocess.  This is necessary to ensure that with the upcoming full
multiprocess support always resumes the correct process without having
to resort to the legacy Hc packets.

Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D131758
2022-08-19 09:02:20 +02:00
Jason Molenda 96d12187b3 Allow firmware binaries to be specified only by load address
Add support to Mach-O corefiles and to live gdb remote serial protocol
connections for the corefile/remote stub to provide a list of load
addresses of binaries that should be found & loaded by lldb, and nothing
else.  lldb will try to parse the binary out of memory, and if it can
find a UUID, try to find a binary & its debug information based on the
UUID, falling back to using the memory image if it must.

A bit of code unification from three parts of lldb that were loading
individual binaries already, so there is a shared method in
DynamicLoader to handle all of the variations they were doing.

Re-landing this with a uuid_is_null() implementation added to
Utility/UuidCompatibility.h for non-Darwin systems.

Differential Revision: https://reviews.llvm.org/D130813
rdar://94249937
rdar://94249384
2022-08-02 14:14:16 -07:00
Jason Molenda 803386da2f Revert "Allow firmware binaries to be specified only by load address"
This reverts commit d8879fba88.

Debian bot failure; I included <uuid/uuid.h> to get uuid_is_null() but
don't get it there.  Will memcmp or whatever & recommit.
2022-08-02 13:53:34 -07:00
Jason Molenda d8879fba88 Allow firmware binaries to be specified only by load address
Add support to Mach-O corefiles and to live gdb remote serial protocol
connections for the corefile/remote stub to provide a list of load
addresses of binaries that should be found & loaded by lldb, and nothing
else.  lldb will try to parse the binary out of memory, and if it can
find a UUID, try to find a binary & its debug information based on the
UUID, falling back to using the memory image if it must.

A bit of code unification from three parts of lldb that were loading
individual binaries already, so there is a shared method in
DynamicLoader to handle all of the variations they were doing.

Differential Revision: https://reviews.llvm.org/D130813
rdar://94249937
rdar://94249384
2022-08-02 13:49:30 -07:00
Michał Górny 8068751189 [lldb] [gdb-remote] Refactor killing process and move it to client
Refactor the code responsible for sending the "k" packet and move it
into GDBRemoteCommunicationClient::KillProcess() method.  This is part
of refactoring to enable multiprocess support in the client,
and to support using the vKill packet instead.

As part of the refactoring, the following functional changes apply:

- Some redundant logging has been removed, as any failures are returned
  via exit_string anyway.

- SetLastStopPacket() is no longer called.  It is used only to populate
  the thread list, and since the process has just exited and we're
  terminating the process instance, there's really no reason to set it.

- On successful kill, exit_string is set to "killed", to clearly
  indicate that the process has terminated on our request rather than
  on its own.

Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D130340
2022-07-25 18:43:32 +02:00
Michał Górny c164efb006 [lldb] [gdb-remote] Remove stray GetSupportsThreadSuffix() method (NFC)
Remove stray GDBRemoteCommunicationClient::GetSupportsThreadSuffix()
method that is not implemented nor used anywhere.
2022-07-14 12:18:17 +02:00
Michał Górny ac666d1799 [lldb] [gdb-remote] Support getting siginfo via API
Add Thread::GetSiginfo() and SBThread::GetSiginfo() methods to retrieve
the siginfo value from server.

Differential Revision: https://reviews.llvm.org/D118055
2022-01-28 17:47:47 +01:00
Michał Górny 59a3f65f5e Revert "[lldb] [gdb-remote] Support getting siginfo via API"
This reverts commit 1a8f60f5f5.
The API requires further work.
2022-01-28 10:15:52 +01:00
Michał Górny 1a8f60f5f5 [lldb] [gdb-remote] Support getting siginfo via API
Add Thread::GetSiginfo() and SBThread::GetSiginfo() methods to retrieve
the siginfo value from server.

Differential Revision: https://reviews.llvm.org/D118055
2022-01-27 13:33:47 +01:00
Jason Molenda 8a26ba6a02 Load binary by UUID from qProcessInfo packet fields
Support three new keys in the qProcessInfo response from the remote
gdb stub to handle the case of attaching to a core running some type
of standalone/firmware code and the stub knows the UUID and load
address-or-slide for the binary.  There will be no proper DynamicLoader
plugin in this scenario, but we can try to locate and load the binary
into lldb at the correct offset.

Differential Revision: https://reviews.llvm.org/D116211
rdar://75191077
2021-12-23 15:20:50 -08:00
Michał Górny 3f1372365a [lldb] Support gdbserver signals
GDB and LLDB use different signal models.  GDB uses a predefined set
of signal codes, and maps platform's signos to them.  On the other hand,
LLDB has historically simply passed native signos.

In order to improve compatibility between LLDB and gdbserver, the GDB
signal model should be used.  However, GDB does not provide a mapping
for all existing signals on Linux and unsupported signals are passed
as 'unknown'.  Limiting LLDB to this behavior could be considered
a regression.

To get the best of both worlds, use the LLDB signal model when talking
to lldb-server, and the GDB signal model otherwise.  For this purpose,
new versions of lldb-server indicate "native-signals+" via qSupported.
At the same time, we also detect older versions of lldb-server
via QThreadSuffixSupported for backwards compatibility.  If neither test
succeeds, we assume gdbserver or another implementation using GDB model.

Differential Revision: https://reviews.llvm.org/D108078
2021-11-10 09:38:55 +01:00
Pavel Labath f5158ca48c Modernize Platform::GetOSKernelDescription 2021-10-27 10:46:47 +02:00
Pavel Labath 40e4ac3e5b [lldb] Modernize Platform::GetOSBuildString 2021-10-25 15:58:58 +02:00
Pavel Labath f4145c074c [lldb/gdb-remote] Refactor ReadExtFeature
replace stl and lldb apis with standard llvm ones.
2021-10-08 10:43:37 +02:00
Pavel Labath 81a2f39307 [lldb/gdb-remote] Delete SendPacketsAndConcatenateResponses
ReadExtFeature provides equivalent functionality. Also fix a but in
ReadExtFeature, which prevented it from being used for auxv data (it
contains nul characters).
2021-10-07 13:09:27 +02:00
Pavel Labath 156cb4cc64 [lldb] Remove non-stop mode code
We added some support for this mode back in 2015, but the feature was
never productionized. It is completely untested, and there are known
major structural lldb issues that need to be resolved before this
feature can really be supported.

It also complicates making further changes to stop reply packet
handling, which is what I am about to do.

Differential Revision: https://reviews.llvm.org/D110553
2021-09-28 14:13:50 +02:00
Michał Górny 6ba3f7237d [lldb] [gdb-remote] Implement the vRun packet
Implement the simpler vRun packet and prefer it over the A packet.
Unlike the latter, it tranmits command-line arguments without redundant
indices and lengths.  This also improves GDB compatibility since modern
versions of gdbserver do not implement the A packet at all.

Make qLaunchSuccess not obligatory when using vRun.  It is not
implemented by gdbserver, and since vRun returns the stop reason,
we can assume it to be successful.

Differential Revision: https://reviews.llvm.org/D107931
2021-09-10 14:08:36 +02:00
Michał Górny 501eaf8877 [lldb] [gdb-remote] Add fallbacks for vFile:mode and vFile:exists
Add a GDB-compatible fallback to vFile:fstat for vFile:mode, and to
vFile:open for vFile:exists.  Note that this is only partial fallback,
as it fails if the file cannot be opened.

Differential Revision: https://reviews.llvm.org/D107811
2021-09-10 14:08:36 +02:00
Michał Górny 21e2d7ce43 [lldb] [gdb-remote] Implement fallback to vFile:stat for GetFileSize()
Implement a fallback to getting the file size via vFile:stat packet
when the remote server does not implement vFile:size.  This makes it
possible to query file sizes from remote gdbserver.

Note that unlike vFile:size, the fallback will not work if the server is
unable to open the file.

While at it, add a few tests for the 'platform get-size' command.

Differential Revision: https://reviews.llvm.org/D107780
2021-09-10 11:09:35 +02:00
David Spickett d2189b5c4b [lldb] Remove unused GDBRemoteCommunicationClient::SendAttach function
Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D109427
2021-09-08 15:14:02 +00:00
Michał Górny 25fbbc5936 [lldb] Support SaveCore() from gdb-remote client
Extend PluginManager::SaveCore() to support saving core dumps
via Process plugins.  Implement the client-side part of qSaveCore
request in the gdb-remote plugin, that creates the core dump
on the remote host and then uses vFile packets to transfer it.

Differential Revision: https://reviews.llvm.org/D101329
2021-09-06 18:33:02 +02:00
Michał Górny 0a1d80d56e [lldb] [gdb-remote client] Support minimal fork/vfork handling
Add a support for handling fork/vfork stops in LLGS client.  At this
point, it only sends a detach packet for the newly forked child
(and implicitly resumes the parent).

Differential Revision: https://reviews.llvm.org/D100206
2021-08-30 10:24:38 +02:00
David Spickett 5ea091a817 [lldb][AArch64] Add memory tag writing to lldb
This adds memory tag writing to Process and the
GDB remote code. Supporting work for the
"memory tag write" command. (to follow)

Process WriteMemoryTags is similair to ReadMemoryTags.
It will pack the tags then call DoWriteMemoryTags.
That function will send the QMemTags packet to the gdb-remote.

The QMemTags packet follows the GDB specification in:
https://sourceware.org/gdb/current/onlinedocs/gdb/General-Query-Packets.html#General-Query-Packets

Note that lldb-server will be treating partial writes as
complete failures. So lldb doesn't need to handle the partial
write case in any special way.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D105181
2021-07-27 15:18:42 +01:00
Jim Ingham 379f24ffde Revert "Revert "Reset the wakeup timeout when we re-enter the continue wait.""
This reverts commit 82a3883715.

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
Michał Górny aa319f544a [lldb] [gdb-remote client] Support switching PID along with TID
Extend the SetCurrentThread() method to support specifying an alternate
PID to switch to.  This makes it possible to issue requests to forked
processes.

Differential Revision: https://reviews.llvm.org/D100262
2021-07-02 21:33:50 +02:00
Michał Górny 02ef0f5ab4 [lldb] [gdb-remote client] Refactor SetCurrentThread*()
Refactor SetCurrentThread() and SetCurrentThreadForRun() to reduce code
duplication and simplify it.  Both methods now call common
SendSetCurrentThreadPacket() that implements the common protocol
exchange part (the only variable is sending `Hg` vs `Hc`) and returns
the selected TID.  The logic is rewritten to use a StreamString
instead of snprintf().

A side effect of the change is that thread-id sent is now zero-padded.
However, this should not have practical impact on the server as both
forms are equivalent.

Differential Revision: https://reviews.llvm.org/D100459
2021-07-02 14:36:17 +02:00
David Spickett 5d34362001 [lldb][AArch64] Add MTE memory tag reading to lldb
This adds GDB client support for the qMemTags packet
which reads memory tags. Following the design
which was recently committed to GDB.

https://sourceware.org/gdb/current/onlinedocs/gdb/General-Query-Packets.html#General-Query-Packets
(look for qMemTags)

lldb commands will use the new Process methods
GetMemoryTagManager and ReadMemoryTags.

The former takes a range and checks that:
* The current process architecture has an architecture plugin
* That plugin provides a MemoryTagManager
* That the range of memory requested lies in a tagged range
  (it will expand it to granules for you)

If all that was true you get a MemoryTagManager you
can give to ReadMemoryTags.

This two step process is done to allow commands to get the
tag manager without having to read tags as well. For example
you might just want to remove a logical tag, or error early
if a range with tagged addresses is inverted.

Note that getting a MemoryTagManager doesn't mean that the process
or a specific memory range is tagged. Those are seperate checks.
Having a tag manager just means this architecture *could* have
a tagging feature enabled.

An architecture plugin has been added for AArch64 which
will return a MemoryTagManagerAArch64MTE, which was added in a
previous patch.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D95602
2021-06-24 17:17:10 +01:00
David Spickett 8d58fbd09e [lldb][AArch64] Add memory-tagging qSupported feature
This feature "memory-tagging+" indicates that lldb-server
supports memory tagging packets. (added in a later patch)

We check HWCAP2_MTE to decide whether to enable this
feature for Linux.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D97282
2021-06-24 15:43:20 +01:00
Jason Molenda 9ea6dd5cfa Add a corefile style option to process save-core; skinny corefiles
Add a new feature to process save-core on Darwin systems -- for
lldb to create a user process corefile with only the dirty (modified
memory) pages included.  All of the binaries that were used in the
corefile are assumed to still exist on the system for the duration
of the use of the corefile.  A new --style option to process save-core
is added, so a full corefile can be requested if portability across
systems, or across time, is needed for this corefile.

debugserver can now identify the dirty pages in a memory region
when queried with qMemoryRegionInfo, and the size of vm pages is
given in qHostInfo.

Create a new "all image infos" LC_NOTE for Mach-O which allows us
to describe all of the binaries that were loaded in the process --
load address, UUID, file path, segment load addresses, and optionally
whether code from the binary was executing on any thread.  The old
"read dyld_all_image_infos and then the in-memory Mach-O load
commands to get segment load addresses" no longer works when we
only have dirty memory.

rdar://69670807
Differential Revision: https://reviews.llvm.org/D88387
2021-06-20 12:26:54 -07:00
Jonas Devlieghere 9494c510af [lldb] Use C++11 default member initializers
This converts a default constructor's member initializers into C++11
default member initializers. This patch was automatically generated with
clang-tidy and the modernize-use-default-member-init check.

$ run-clang-tidy.py -header-filter='lldb' -checks='-*,modernize-use-default-member-init' -fix

This is a mass-refactoring patch and this commit will be added to
.git-blame-ignore-revs.

Differential revision: https://reviews.llvm.org/D103483
2021-06-09 09:43:13 -07:00
Jim Ingham 82a3883715 Revert "Reset the wakeup timeout when we re-enter the continue wait."
This reverts commit bd5751f3d2.
This patch series is causing us to every so often miss switching
the state from eStateRunning to eStateStopped when we get the stop
packet from the debug server.

Reverting till I can figure out how that could be happening.
2021-05-17 15:37:26 -07:00
Jim Ingham 9558b602b2 Add an "interrupt timeout" to Process, and pipe that through the
ProcessGDBRemote plugin layers.

Also fix a bug where if we tried to interrupt, but the ReadPacket
wakeup timer woke us up just after the timeout, we would break out
the switch, but then since we immediately check if the response is
empty & fail if it is, we could end up actually only giving a
small interval to the interrupt.

Differential Revision: https://reviews.llvm.org/D102085
2021-05-11 11:57:08 -07:00
Jonas Devlieghere db2da0c8f9 [lldb] Set addressable bits from qHostInfo
Read the number of addressable bits from the qHostInfo packet and use it
to set the code and data address mask in the process. The data
(addressing_bits) is already present in the packet.

Differential revision: https://reviews.llvm.org/D100520
2021-04-16 13:49:38 -07:00
Michał Górny ff31af4f55 [lldb] [gdb-remote client] Refactor handling qSupported
Refactor the qSupported handler to split the reply into an array,
and identify features within the array rather than searching the string
for partial matches.  While at it, use StringRef.split() to process
the compression list instead of reinventing the wheel.

Switch the arguments to MaybeEnableCompression() to use an ArrayRef
of StringRefs to simplify parameter passing from GetRemoteQSupported().

Differential Revision: https://reviews.llvm.org/D100146
2021-04-13 11:20:11 +02:00
Ahmed Bougacha 6c4f2508e4 Revert "[lldb] [gdb-remote client] Refactor handling qSupported"
This reverts commit 3842de49f6.

It fails to build, with errors such as:
  GDBRemoteCommunicationClient.cpp:1005:20:
  error: no viable overloaded '='
          avail_name = compression;
2021-04-12 18:06:09 -07:00
Michał Górny 3842de49f6 [lldb] [gdb-remote client] Refactor handling qSupported
Refactor the qSupported handler to split the reply into an array,
and identify features within the array rather than searching the string
for partial matches.  While at it, use StringRef.split() to process
the compression list instead of reinventing the wheel.

Switch the arguments to MaybeEnableCompression() to use an ArrayRef
of StringRefs to simplify parameter passing from GetRemoteQSupported().

Differential Revision: https://reviews.llvm.org/D100146
2021-04-13 00:23:07 +02:00
Michał Górny b601c67192 [lldb] [client] Support for multiprocess extension
Add a minimal support for the multiprocess extension in gdb-remote
client.  It accepts PIDs as part of thread-ids, and rejects PIDs that
do not match the current inferior.

Differential Revision: https://reviews.llvm.org/D99603
2021-04-08 13:45:07 +02:00
Walter Erquinigo 0b69756110 [trace][intel-pt] Implement trace start and trace stop
This implements the interactive trace start and stop methods.

This diff ended up being much larger than I anticipated because, by doing it, I found that I had implemented in the beginning many things in a non optimal way. In any case, the code is much better now.

There's a lot of boilerplate code due to the gdb-remote protocol, but the main changes are:

- New tracing packets: jLLDBTraceStop, jLLDBTraceStart, jLLDBTraceGetBinaryData. The gdb-remote packet definitions are quite comprehensive.
- Implementation of the "process trace start|stop" and "thread trace start|stop" commands.
- Implementaiton of an API in Trace.h to interact with live traces.
- Created an IntelPTDecoder for live threads, that use the debugger's stop id as checkpoint for its internal cache.
- Added a functionality to stop the process in case "process tracing" is enabled and a new thread can't traced.
- Added tests

I have some ideas to unify the code paths for post mortem and live threads, but I'll do that in another diff.

Differential Revision: https://reviews.llvm.org/D91679
2021-03-30 17:31:37 -07:00
Michał Górny 6c1a8039de [lldb] [server] Support for multiprocess extension
Add a minimal support for the multiprocess extension in lldb-server.
The server indicates support for it via qSupported, and accepts
thread-ids containing a PID.  However, it still does not support
debugging more than one inferior, so any other PID value results
in an error.

Differential Revision: https://reviews.llvm.org/D98482
2021-03-30 15:09:27 +02:00
Walter Erquinigo 21555fff4d [intel-pt][trace] Implement a "get supported trace type" packet
Depends on D89283.

The goal of this packet (jTraceGetSupportedType) is to be able to query the gdb-server for the tracing technology that can work for the current debuggeer, which can make the user experience simpler but allowing the user to simply type

  thread trace start

to start tracing the current thread without even telling the debugger to use "intel-pt", for example. Similarly, `thread trace start [args...]` would accept args beloging to the working trace type.

Also, if the user typed

  help thread trace start

We could directly show the help information of the trace type that is supported for the target, or mention instead that no tracing is supported, if that's the case.

I added some simple tests, besides, when I ran this on my machine with intel-pt support, I got

  $ process plugin packet send "jTraceSupportedType"
    packet: jTraceSupportedType
  response: {"description":"Intel Processor Trace","pluginName":"intel-pt"}

On a machine without intel-pt support, I got

  $ process plugin packet send "jTraceSupportedType"
    packet: jTraceSupportedType
  response: E00;

Reviewed By: clayborg, labath

Differential Revision: https://reviews.llvm.org/D90490
2020-11-11 10:35:58 -08:00
Med Ismail Bennani addb5148f5 [lldb/Target] Add custom interpreter option to `platform shell`
This patch adds the ability to use a custom interpreter with the
`platform shell` command. If the user set the `-s|--shell` option
with the path to a binary, lldb passes it down to the platform's
`RunShellProcess` method and set it as the shell to use in
`ProcessLaunchInfo to run commands.

Note that not all the Platforms support running shell commands with
custom interpreters (i.e. RemoteGDBServer is only expected to use the
default shell).

This patch also makes some refactoring and cleanups, like swapping
CString for StringRef when possible and updating `SBPlatformShellCommand`
with new methods and a new constructor.

rdar://67759256

Differential Revision: https://reviews.llvm.org/D86667

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2020-09-02 16:36:10 +02:00
Gongyu Deng 3cd8d7b172 [lldb] Remote disk file/directory completion for platform commands
1. Extended the gdb-remote communication related classes with disk file/directory
   completion functions;
2. Added two common completion functions RemoteDiskFiles and
   RemoteDiskDirectories based on the functions above;
3. Added completion for these commands:
   A. platform get-file <remote-file> <local-file>;
   B. platform put-file <local-file> <remote-file>;
   C. platform get-size <remote-file>;
   D. platform settings -w <remote-dir>;
   E. platform open file <remote-file>.
4. Added related tests for client and server;
5. Updated docs/lldb-platform-packets.txt.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D85284
2020-08-24 17:55:54 +02:00
Konrad Kleine eaebcbc679 [lldb] NFC remove DISALLOW_COPY_AND_ASSIGN
Summary:
This is how I applied my clang-tidy check (see
https://reviews.llvm.org/D80531) in order to remove
`DISALLOW_COPY_AND_ASSIGN` and have deleted copy ctors and deleted
assignment operators instead.

```
lang=bash
grep DISALLOW_COPY_AND_ASSIGN /opt/notnfs/kkleine/llvm/lldb -r -l | sort | uniq > files

for i in $(cat files);
do
  clang-tidy \
    --checks="-*,modernize-replace-disallow-copy-and-assign-macro" \
    --format-style=LLVM \
    --header-filter=.* \
    --fix \
    -fix-errors \
    $i;
done
```

Reviewers: espindola, labath, aprantl, teemperor

Reviewed By: labath, aprantl, teemperor

Subscribers: teemperor, aprantl, labath, emaste, sbc100, aheejin, MaskRay, arphaman, usaxena95, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D80543
2020-06-02 13:23:53 -04:00
Jonas Devlieghere 638b06cf29 [lldb/Utility] Replace ProcessInstanceInfoList with std::vector. (NFCI)
Replace ProcessInstanceInfoList with std::vector<ProcessInstanceInfo>
and update the call sites.
2020-03-12 14:10:25 -07:00
Pavel Labath d4eca120ac [lldb/gdb-remote] Add support for the qOffsets packet
Summary:
This packet is necessary to make lldb work with the remote-gdb stub in
user mode qemu when running position-independent binaries. It reports
the relative position (load bias) of the loaded executable wrt. the
addresses in the file itself.

Lldb needs to know this information in order to correctly set the load
address of the executable. Normally, lldb would be able to find this out
on its own by following the breadcrumbs in the process auxiliary vector,
but we can't do this here because qemu does not support the
qXfer:auxv:read packet.

This patch does not implement full scope of the qOffsets packet (it only
supports packets with identical code, data and bss offsets), because it
is not fully clear how should the different offsets be handled and I am
not aware of a producer which would make use of this feature (qemu will
always
<https://github.com/qemu/qemu/blob/master/linux-user/elfload.c#L2436>
return the same value for code and data offsets). In fact, even gdb
ignores the offset for the bss sections, and uses the "data" offset
instead.  So, until the we need more of this packet, I think it's best
to stick to the simplest solution possible. This patch simply rejects
replies with non-uniform offsets.

Reviewers: clayborg, jasonmolenda

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D74598
2020-02-26 10:18:58 +01:00
Jonas Devlieghere cdc514e4c6 [lldb] Update header guards to be consistent and compliant with LLVM (NFC)
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
2020-02-17 23:15:40 -08:00