Commit Graph

47 Commits

Author SHA1 Message Date
Walter Erquinigo bf9f21a28b [trace][intel-pt] Create basic SB API
This adds a basic SB API for creating and stopping traces.
Note: This doesn't add any APIs for inspecting individual instructions. That'd be a more complicated change and it might be better to enhande the dump functionality to output the data in binary format. I'll leave that for a later diff.

This also enhances the existing tests so that they test the same flow using both the command interface and the SB API.

I also did some cleanup of legacy code.

Differential Revision: https://reviews.llvm.org/D103500
2021-06-17 15:14:47 -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
Walter Erquinigo a4ee79c8ae Fix errors in 0b69756110
Errors found in
https://lab.llvm.org/buildbot/#/builders/68/builds/9681/steps/6/logs/stdio
2021-03-30 18:03:02 -07:00
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
David Spickett 32541685b2 [lldb][AArch64/Linux] Show memory tagged memory regions
This extends the "memory region" command to
show tagged regions on AArch64 Linux when the MTE
extension is enabled.

(lldb) memory region the_page
[0x0000fffff7ff8000-0x0000fffff7ff9000) rw-
memory tagging: enabled

This is done by adding an optional "flags" field to
the qMemoryRegion packet. The only supported flag is
"mt" but this can be extended.

This "mt" flag is read from /proc/{pid}/smaps on Linux,
other platforms will leave out the "flags" field.

Where this "mt" flag is received "memory region" will
show that it is enabled. If it is not or the target
doesn't support memory tagging, the line is not shown.
(since majority of the time tagging will not be enabled)

Testing is added for the existing /proc/{pid}/maps
parsing and the new smaps parsing.
Minidump parsing has been updated where needed,
though it only uses maps not smaps.

Target specific tests can be run with QEMU and I have
added MTE flags to the existing helper scripts.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D87442
2020-11-20 11:21:59 +00:00
Walter Erquinigo d2f18e6b1e Fix 21555fff4d
Buildbot failed on Windows
http://lab.llvm.org:8011/#/builders/83/builds/693

Error: On Windows, std::future can't hold an Expected, as it doesn't have a default
constructor.

Solution: Use std::future<bool> instead of std::future<Expected<T>>
2020-11-11 12:30:24 -08:00
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
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
Benjamin Kramer 777180a32b [ADT] Make StringRef's std::string conversion operator explicit
This has the same behavior as converting std::string_view to
std::string. This is an expensive conversion, so explicit conversions
are helpful for avoiding unneccessary string copies.
2020-01-28 23:47:07 +01:00
Benjamin Kramer adcd026838 Make llvm::StringRef to std::string conversions explicit.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.
2020-01-28 23:25:25 +01:00
Raphael Isemann 808142876c [lldb][NFC] Fix all formatting errors in .cpp file headers
Summary:
A *.cpp file header in LLDB (and in LLDB) should like this:
```
//===-- TestUtilities.cpp -------------------------------------------------===//
```
However in LLDB most of our source files have arbitrary changes to this format and
these changes are spreading through LLDB as folks usually just use the existing
source files as templates for their new files (most notably the unnecessary
editor language indicator `-*- C++ -*-` is spreading and in every review
someone is pointing out that this is wrong, resulting in people pointing out that this
is done in the same way in other files).

This patch removes most of these inconsistencies including the editor language indicators,
all the different missing/additional '-' characters, files that center the file name, missing
trailing `===//` (mostly caused by clang-format breaking the line).

Reviewers: aprantl, espindola, jfb, shafik, JDevlieghere

Reviewed By: JDevlieghere

Subscribers: dexonsmith, wuzish, emaste, sdardis, nemanjai, kbarton, MaskRay, atanasyan, arphaman, jfb, abidh, jsji, JDevlieghere, usaxena95, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D73258
2020-01-24 08:52:55 +01:00
Jonas Devlieghere 2783d81791 [JSON] Use LLVM's library for encoding JSON in StructuredData
This patch replaces the hand-rolled JSON emission in StructuredData with
LLVM's JSON library.

Differential revision: https://reviews.llvm.org/D68248

llvm-svn: 373359
2019-10-01 17:41:48 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
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
2019-01-19 08:50:56 +00:00
Jonas Devlieghere 9e046f02e3 Add GDB remote packet reproducer.
llvm-svn: 346780
2018-11-13 19:18:16 +00:00
Jonas Devlieghere 8f3be7a32b [FileSystem] Move path resolution logic out of FileSpec
This patch removes the logic for resolving paths out of FileSpec and
updates call sites to rely on the FileSystem class instead.

Differential revision: https://reviews.llvm.org/D53915

llvm-svn: 345890
2018-11-01 21:05:36 +00:00
Pavel Labath 2f93fd1f50 Represent invalid UUIDs as UUIDs with length zero
Summary:
During the previous attempt to generalize the UUID class, it was
suggested that we represent invalid UUIDs as length zero (previously, we
used an all-zero UUID for that). This meant that some valid build-ids
could not be represented (it's possible however unlikely that a checksum of
some file would be zero) and complicated adding support for variable
length build-ids (should a 16-byte empty UUID compare equal to a 20-byte
empty UUID?).

This patch resolves these issues by introducing a canonical
representation for an invalid UUID. The slight complication here is that
some clients (MachO) actually use the all-zero notation to mean "no UUID
has been set". To keep this use case working (while making it very
explicit about which construction semantices are wanted), replaced the
UUID constructors and the SetBytes functions with named factory methods.
- "fromData" creates a UUID from the given data, and it treats all bytes
  equally.
- "fromOptionalData" first checks the data contents - if all bytes are
  zero, it treats this as an invalid/empty UUID.

Reviewers: clayborg, sas, lemo, davide, espindola

Subscribers: emaste, lldb-commits, arichardson

Differential Revision: https://reviews.llvm.org/D48479

llvm-svn: 335612
2018-06-26 15:12:20 +00:00
Pavel Labath 2cb7cf8e87 FileSpec: Remove PathSyntax enum and use llvm version instead
Summary:
The llvm version of the enum has the same enumerators, with stlightly
different names, so this is mostly just a search&replace exercise. One
concrete benefit of this is that we can remove the function for
converting between the two enums.

To avoid typing llvm::sys::path::Style::windows everywhere I import the
enum into the FileSpec class, so it can be referenced as
FileSpec::Style::windows.

Reviewers: zturner, clayborg

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D46753

llvm-svn: 332247
2018-05-14 14:52:47 +00:00
Pavel Labath 47776cbd2c Fix gdb-remote qMemoryRegionInfo unit tests for xml-enabled builds
In case we are building with xml enabled, the GetMemoryRegionInfo
function will send extra packets to query te extended memory map, which
the tests were not expecting.

Add an expectation for this to the test. Right now, it's just a basic
one which pretends we don't support the extension, however, it would be
also interesting the add a test which verifies the extension-enabled
case.

I also noticed that the test does a pretty lousy job of validating the
returned memory region info, so I add a couple of extra assertions to
improve that.

llvm-svn: 331374
2018-05-02 17:00:33 +00:00
Pavel Labath 8c92c899c6 Fix regression in jModulesInfo packet handling
The recent UUID cleanups exposed a bug in the parsing code for the
jModulesInfo response, which was passing wrong value for the second
argument to UUID::SetFromStringRef (it passed the length of the string,
whereas the correct value should be the number of decoded bytes we
expect to receive).

This was not picked up by tests, because they test with 16-byte uuids,
for which the function happens to do the right thing even if the length
does not match (if the length does not match, the function does not
update m_num_uuid_bytes member, but that member is already 16 to begin
with).

I fix that and add a test with 20-byte uuid to catch if this regresses.
I have also added more safeguards into the parsing code to fail if we
cannot parse the entire uuid field we recieve. While testing the latter
part, I noticed that the "negative" jModulesInfo tests were succeeding
because we were sending malformed json (and not because the json
contents was invalid), so I make those tests a bit more robuts as well.

llvm-svn: 320985
2017-12-18 14:31:44 +00:00
Pavel Labath 38d0632e6a Move Timer and TraceOptions from Core to Utility
Summary:
The classes have no dependencies, and they are used both by lldb and
lldb-server, so it makes sense for them to live in the lowest layers.

Reviewers: zturner, jingham

Subscribers: emaste, mgorny, lldb-commits

Differential Revision: https://reviews.llvm.org/D34746

llvm-svn: 306682
2017-06-29 14:32:17 +00:00
Pavel Labath f2a8bccf85 Move StructuredData from Core to Utility
Summary:
It had a dependency on StringConvert and file reading code, which is not
in Utility. I've replaced that code by equivalent llvm operations.

I've added a unit test to demonstrate that parsing a file still works.

Reviewers: zturner, jingham

Subscribers: kubamracek, mgorny, lldb-commits

Differential Revision: https://reviews.llvm.org/D34625

llvm-svn: 306394
2017-06-27 10:45:31 +00:00
Pavel Labath 93df2fbeab Simplify the gdb-remote unit tests
Instead of every test creating a client-server combo, do that in the
SetUp method of the test fixture. This also means that we can rely on
gtest to not run the test if the SetUp method fails and delete the
if(HasFailure) calls.

llvm-svn: 306013
2017-06-22 15:54:21 +00:00
Pavel Labath 32f29fac41 Fix assorted compiler warnings. NFC
llvm-svn: 304796
2017-06-06 14:06:22 +00:00
Pavel Labath 9f9422b699 Remove unused variables. NFC
llvm-svn: 304794
2017-06-06 13:40:21 +00:00
Abhishek Aggarwal d2746dda60 Replaced StructuredData::Type with eStructuredDataType
...missing from r304138 "Added new API to SBStructuredData class"

llvm-svn: 304147
2017-05-29 11:13:30 +00:00
Ravitheja Addepally e714c4f535 Implementation of remote packets for Trace data.
Summary:
The changes consist of new packets for trace manipulation and
trace collection. The new packets are also documented. The packets
are capable of providing custom trace specific parameters to start
tracing and also retrieve such configuration from the server.

Reviewers: clayborg, lldb-commits, tberghammer, labath, zturner

Reviewed By: clayborg, labath

Subscribers: krytarowski, lldb-commits

Differential Revision: https://reviews.llvm.org/D32585

llvm-svn: 303972
2017-05-26 11:46:27 +00:00
Zachary Turner 97206d5727 Rename Error -> Status.
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
2017-05-12 04:51:55 +00:00
Stephane Sezer 48d1427c30 Verify memory address range validity in GDBRemoteCommunicationClient
Summary:
This aims to verify the validity of the response from the debugging
server in GDBRemoteCommunicationClient::GetMemoryRegionInfo. I was
working with ds2 (https://github.com/facebook/ds2) and encountered a bug
that caused the server's response to have a 'size' value of 0, which
caused lldb to behave incorrectly.

Reviewers: k8stone, labath, clayborg

Reviewed By: labath, clayborg

Subscribers: clayborg, sas, lldb-commits

Differential Revision: https://reviews.llvm.org/D31485

Change by Alex Langford <apl@fb.com>

llvm-svn: 299239
2017-03-31 18:00:48 +00:00
Eugene Zemtsov 7993cc5eed Make LLDB skip server-client roundtrip for signals that don't require any actions
If QPassSignals packaet is supported by lldb-server, lldb-client will
utilize it and ask the server to ignore signals that don't require stops
or notifications.
Such signals will be immediately re-injected into inferior to continue
normal execution.

Differential Revision: https://reviews.llvm.org/D30520

llvm-svn: 297231
2017-03-07 21:34:40 +00:00
Zachary Turner 666cc0b291 Move DataBuffer / DataExtractor and friends from Core -> Utility.
llvm-svn: 296943
2017-03-04 01:30:05 +00:00
Zachary Turner 1e021a162e [Windows] Remove the #include <eh.h> hack.
Prior to MSVC 2015 we had to manually include this header any
time we were going to include <thread> or <future> due to a
bug in MSVC's STL implementation.  This has been fixed in MSVC
for some time now, and we require VS 2015 minimum, so we can
remove this across all subprojects.

llvm-svn: 296906
2017-03-03 20:21:59 +00:00
Pavel Labath 2f7cfaf4ad Switch TestPacketSpeedJSON to use the llvm chrono formatter
llvm-svn: 294739
2017-02-10 11:49:40 +00:00
Pavel Labath 763f1c453b Fix jModulesInfo handling for cross-path syntax debugging
We were sending paths with the host path separator, which meant the remote
target did not understand our packets correctly.

llvm-svn: 291103
2017-01-05 13:18:46 +00:00
Pavel Labath 2fd9a1e0d9 Fix GDBRemoteCommunicationClientTest.TestPacketSpeedJSON
The mock server was listening for only one packet (I forgot to put a loop around
it), which caused the client to stall in debug builds, as the timeout there is
1000 seconds. In case of a release builds the test would just silently succeed as
the tested function does not check or report errors (which should be fixed).

This fixes the test by adding the server loop. Since the test was taking quite a
long time now (8s), I have added a parameter to control the amount of data sent
(default 4MB), and call it with a smaller value in the test, to make the test run
faster.

llvm-svn: 285992
2016-11-04 11:49:06 +00:00
Pavel Labath 3aa049102f Remove usages of TimeValue from gdb-remote process plugin
Summary:
Most of the changes are very straight-forward, the only tricky part was the
"packet speed-test" function, which is very time-heavy. As the function was
completely untested, I added a quick unit smoke test for it.

Reviewers: clayborg, zturner

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D25391

llvm-svn: 285602
2016-10-31 17:19:42 +00:00
Pavel Labath 6e5e49fbdf Fix new gdb-remote client unit test for windows
The behaviour of FileSpec differed between host OS versions. Hardcode the path
syntax to posix, as we don't care about that in this test.

llvm-svn: 281025
2016-09-09 09:49:54 +00:00
Pavel Labath 2f1fbaebe2 gdb-remote: Add jModulesInfo packet
Summary:
This adds the jModulesInfo packet, which is the equivalent of qModulesInfo, but it enables us to
query multiple modules at once. This makes a significant speed improvement in case the
application has many (over a hundred) modules, and the communication link has a non-negligible
latency. This functionality is accessed by ProcessGdbRemote::PrefetchModuleSpecs(), which does
the caching. GetModuleSpecs() is modified to first consult the cache before asking the remote
stub. PrefetchModuleSpecs is currently only called from POSIX-DYLD dynamic loader plugin, after
it reads the list of modules from the inferior memory, but other uses are possible.

This decreases the attach time to an android application by about 40%.

Reviewers: clayborg

Subscribers: tberghammer, lldb-commits, danalbert

Differential Revision: https://reviews.llvm.org/D24236

llvm-svn: 280919
2016-09-08 10:07:04 +00:00
Pavel Labath 46031e6fec Fix unittest compilation on windows
After the reformat, the unittests do not compile due to missing due to redefinition errors
between PosixApi.h and ucrt/direct.h. This is a bit of a shot in the dark, as I have not tested
it on windows, but I am restoring the original include order, so it should hopefully fix it.

llvm-svn: 280793
2016-09-07 08:46:50 +00:00
Kate Stone b9c1b51e45 *** This commit represents a complete reformatting of the LLDB source code
*** 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
2016-09-06 20:57:50 +00:00
Pavel Labath 5c95ee4dd8 Revert "gdb-remote: Make the sequence mutex non-recursive"
This reverts commit r279725 as it breaks "dynamic register size" feature of mips.

llvm-svn: 280088
2016-08-30 13:56:11 +00:00
Pavel Labath 0faf37333c gdb-remote: Make the sequence mutex non-recursive
Summary:
This is a preparatory commit for D22914, where I'd like to replace this mutex by an R/W lock
(which is also not recursive). This required a couple of changes:
- The only caller of Read/WriteRegister, GDBRemoteRegisterContext class, was already acquiring
  the mutex, so these functions do not need to. All functions which now do not take a lock, take
  an lock argument instead, to remind the caller of this fact.
- GetThreadSuffixSupported() was being called from locked and unlocked contexts (including
  contexts where the process was running, and the call would fail if it did not have the result
  cached). I have split this into two functions, one which computes the thread suffix support and
  caches it (this one always takes the lock), and another, which returns the cached value (and
  never needs to take the lock). This feels quite natural as ProcessGdbRemote was already
  pre-caching this value at the start.

Reviewers: clayborg

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D23802

llvm-svn: 279725
2016-08-25 08:34:57 +00:00
Pavel Labath b42b48e051 Remove the last manually constructed packet from gdb-remote register context + small refactor
Summary:
The tricky part here was that the exisiting implementation of WriteAllRegisters was expecting
hex-encoded data (as that was what the first implementation I replaced was using, but here we had
binary data to begin with. I thought the read/write register functions would be more useful if
they handled the hex-encoding themselves (all the other client functions provide the responses in
a more-or-less digested form). The read functions return a DataBuffer, so they can allocate as
much memory as they need to, while the write functions functions take an llvm::ArrayRef, as that
can be constructed from pretty much anything.

Reviewers: clayborg

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D23659

llvm-svn: 279232
2016-08-19 12:31:49 +00:00
Pavel Labath 27402d2a12 Move QSyncThreadState packet generation to the gdb-remote client
llvm-svn: 279057
2016-08-18 12:32:41 +00:00
Pavel Labath 4b6f9591d3 gdb-remote: Centralize thread specific packet handling
Summary:
Before this, each function had a copy of the code which handled appending of the thread suffix to
the packet (or using $Hg instead). I have moved that code into a single function and made
everyone else use that. The function takes the partial packet as a StreamString rvalue reference,
to avoid a copy and to remind the users that the packet will have undeterminate contents after
the call.

This also fixes the incorrect formatting of the QRestoreRegisterState packet in case thread
suffix is not supported.

Reviewers: clayborg

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D23604

llvm-svn: 279040
2016-08-18 08:30:03 +00:00
Pavel Labath 8e8e5061b8 Fix unittests on windows after r278915
Apparently clang will happily capture a const variable in a lambda without it being specified in
the capture clause. MSVC does not like that.

llvm-svn: 278925
2016-08-17 12:00:19 +00:00
Pavel Labath 56d7262b69 Move packet construction from GDBRemoteRegisterContext go the communication class
Summary:
When saving/restoring registers the GDBRemoteRegisterContext class was manually constructing
the register save/restore packets. This creates appropriate helper functions in
GDBRemoteCommunicationClient, and switches the class to use those. It also removes what a
duplicate packet send in some of those functions, a thing that I can only attribute to a bad
merge artefact.

I also add a test framework for testing gdb-remote client functionality and add tests for the new
functions I introduced. I'd like to be able to test the register context changes in isolation as
well, but currently there doesn't seem to be a way to reasonably construct a standalone register
context object, so we'll have to rely on the end-to-end tests to verify that.

Reviewers: clayborg

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D23553

llvm-svn: 278915
2016-08-17 08:53:31 +00:00