Commit Graph

630 Commits

Author SHA1 Message Date
Pavel Labath e4fc4ef463 [LLGS] Limit jThreadsInfo to only the most important registers for now
Summary:
It seems that reading of register data is the biggest bottleneck in LLGS at the moment. Sending
four registers instead of the full GPR set increases the jThreadsInfo processing time about
6-fold. Until we figure out where is this time going, this commit limits the amount of data we
send to provide a more fluid debugging experience.

Reviewers: tberghammer, ovyalov

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D11264

llvm-svn: 242517
2015-07-17 10:27:42 +00:00
Pavel Labath 4a4bb12e0d Add jThreadsInfo support to lldb-server
Summary:
This commit adds initial support for the jThreadsInfo packet to lldb-server. The current
implementation does not expedite inferior memory.  I have also added a description of the new
packet to our protocol documentation (mostly taken from Greg's earlier commit message).

Reviewers: clayborg, ovyalov, tberghammer

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D11187

llvm-svn: 242402
2015-07-16 14:14:35 +00:00
Pavel Labath 5abe726911 Revert "[NativeProcessLinux] Integrate MainLoop"
This seems to be causing major slowdows on the android buildbot. Reverting while I investigate.

llvm-svn: 242391
2015-07-16 08:45:03 +00:00
Greg Clayton a5801ade5a Added the ability to get JSON thread stop info with thread ID and stop info only in the normal stop reply packets using the new "jthreads" key value pair.
This allows stepping operations that don't ever do a public stop to get all the info they need without having to send a jThreadsInfo packet since those tend to be large.

This patch will be followed by a patch that will detect when we do a public stop, and when that happens we will send a jThreadsInfo packet at that time to get all expedited registers and memory.

llvm-svn: 242352
2015-07-15 22:59:03 +00:00
Pavel Labath 827965c33c [NativeProcessLinux] Integrate MainLoop
Summary:
This commit integrates MainLoop into NativeProcessLinux. By registering a SIGCHLD handler with
the llgs main loop, we can get rid of the special monitor thread in NPL, which saves as a lot of
thread ping-pong when responding to client requests (e.g. qThreadInfo processing time has been
reduced by about 40%). It also makes the code simpler, IMHO.

Reviewers: ovyalov, clayborg, tberghammer, chaoren

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D11150

llvm-svn: 242305
2015-07-15 17:20:01 +00:00
Jim Ingham 4920a4ef56 Fix another little nit with detach and keep stopped, you have to check
both for packet success and that the response is OK.

llvm-svn: 242262
2015-07-15 00:59:25 +00:00
Jason Molenda 2a66738f5c Correct length of packet that GDBRemoteCommunicationClient::Detach
should send when detaching and leaving the remote process/system
halted.  Previously only the 'D' initial char was sent, which
resumed the process like a normal detach.

llvm-svn: 242256
2015-07-15 00:16:09 +00:00
Jason Molenda fea7765219 Add comment explaning sanity check on packet size in the packet decompression method.
llvm-svn: 242184
2015-07-14 19:19:07 +00:00
Jason Molenda 21c34ac419 Fix off-by-one error in the packet decompression routine
that would not pass through empty ("unsupported packet") replies
correctly.

llvm-svn: 242119
2015-07-14 04:51:05 +00:00
Chaoren Lin 98d0a4b39a Refactor Unix signals.
Summary:
- Consolidate Unix signals selection in UnixSignals.
- Make Unix signals available from platform.
- Add jSignalsInfo packet to retrieve Unix signals from remote platform.
- Get a copy of the platform signal for each remote process.
- Update SB API for signals.
- Update signal utility in test suite.

Reviewers: ovyalov, clayborg

Subscribers: chaoren, jingham, labath, emaste, tberghammer, lldb-commits

Differential Revision: http://reviews.llvm.org/D11094

llvm-svn: 242101
2015-07-14 01:09:28 +00:00
Pavel Labath 77dc9569c6 Introduce a MainLoop class and switch llgs to use it
Summary:
This is the first part of our effort to make llgs single threaded. Currently, llgs consists of
about three threads and the synchronisation between them is a major source of latency when
debugging linux and android applications.

In order to be able to go single threaded, we must have the ability to listen for events from
multiple sources (primarily, client commands coming over the network and debug events from the
inferior) and perform necessary actions. For this reason I introduce the concept of a MainLoop.
A main loop has the ability to register callback's which will be invoked upon receipt of certain
events. MainLoopPosix has the ability to listen for file descriptors and signals.

For the moment, I have merely made the GDBRemoteCommunicationServerLLGS class use MainLoop
instead of waiting on the network socket directly, but the other threads still remain. In the
followup patches I indend to migrate NativeProcessLinux to this class and remove the remaining
threads.

Reviewers: ovyalov, clayborg, amccarth, zturner, emaste

Subscribers: tberghammer, lldb-commits

Differential Revision: http://reviews.llvm.org/D11066

llvm-svn: 242018
2015-07-13 10:44:55 +00:00
Jason Molenda 20ee21bde6 Add a another packet to the gdb-remote protocol,
jGetLoadedDynamicLibrariesInfos.  This packet is similar to
qXfer:libraries:read except that lldb supplies the number of solibs
that should be reported about, and the start address for the list
of them.  At the initial process launch we'll read the full list
of solibs linked by the process -- at this point we could be using
qXfer:libraries:read -- but on subsequence solib-loaded notifications,
we'll be fetching a smaller number of solibs, often only one or two.

A typical Mac/iOS GUI app may have a couple hundred different 
solibs loaded  - doing all of the loads via memory reads takes 
a couple of megabytes of traffic between lldb and debugserver.
Having debugserver summarize the load addresses of all the solibs
and sending it in JSON requires a couple of hundred kilobytes
of traffic.  It's a significant performance improvement when 
communicating over a slower channel.

This patch leaves all of the logic for loading the libraries
in DynamicLoaderMacOSXDYLD -- it only call over ot ProcesGDBRemote
to get the JSON result.

If the jGetLoadedDynamicLibrariesInfos packet is not implemented,
the normal technique of using memory read packets to get all of
the details from the target will be used.

<rdar://problem/21007465>

llvm-svn: 241964
2015-07-10 23:15:22 +00:00
Pavel Labath d5b310f2a3 Avoid going through Platform when creating a NativeProcessProtocol instance
Summary:
This commit avoids the Platform instance when spawning or attaching to a process in lldb-server.
Instead, I have the server call a (static) method of NativeProcessProtocol directly. The reason
for this is that I believe that NativeProcessProtocol should be decoupled from the Platform
(after all, it always knows which platform it is running on, unlike the rest of lldb).
Additionally, the kind of platform actions a NativeProcessProtocol instance is likely to differ
greatly from the platform actions of the lldb client, so I think the separation makes sense.

After this, the only dependency NativeProcessLinux has on PlatformLinux is the ResolveExecutable
method, which needs additional refactoring.

This is a resubmit of r241672, after it was reverted due to build failueres on non-linux
platforms.

Reviewers: ovyalov, clayborg

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D10996

llvm-svn: 241796
2015-07-09 11:51:11 +00:00
Stephane Sezer 9a7cacb5f6 Implement qXfer:libraries:read.
Summary:
This is used on non-unix platforms, where qXfer:libraries-svr4:read
doesn't make sense. Windows uses that for instance.

Reviewers: clayborg

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D11036

llvm-svn: 241712
2015-07-08 19:14:03 +00:00
Sean Callanan c307c27035 Revert r241672, which breaks the OS X build by introducing a dependency on
platform-specific symbols that are not implemented on OS X.

The build error that caused this is

Undefined symbols for architecture x86_64:
  "lldb_private::NativeProcessProtocol::Attach(unsigned long long, lldb_private::NativeProcessProtocol::NativeDelegate&, std::__1::shared_ptr<lldb_private::NativeProcessProtocol>&)", referenced from:
      lldb_private::process_gdb_remote::GDBRemoteCommunicationServerLLGS::AttachToProcess(unsigned long long) in liblldb-core.a(GDBRemoteCommunicationServerLLGS.o)
  "lldb_private::NativeProcessProtocol::Launch(lldb_private::ProcessLaunchInfo&, lldb_private::NativeProcessProtocol::NativeDelegate&, std::__1::shared_ptr<lldb_private::NativeProcessProtocol>&)", referenced from:
      lldb_private::process_gdb_remote::GDBRemoteCommunicationServerLLGS::LaunchProcess() in liblldb-core.a(GDBRemoteCommunicationServerLLGS.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

llvm-svn: 241688
2015-07-08 16:33:46 +00:00
Pavel Labath 235c8405eb Avoid going through Platform when creating a NativeProcessProtocol instance
Summary:
This commit avoids the Platform instance when spawning or attaching to a process in lldb-server.
Instead, I have the server call a (static) method of NativeProcessProtocol directly. The reason
for this is that I believe that NativeProcessProtocol should be decoupled from the Platform
(after all, it always knows which platform it is running on, unlike the rest of lldb).
Additionally, the kind of platform actions a NativeProcessProtocol instance is likely to differ
greatly from the platform actions of the lldb client, so I think the separation makes sense.

After this, the only dependency NativeProcessLinux has on PlatformLinux is the ResolveExecutable
method, which needs additional refactoring.

Reviewers: ovyalov, clayborg

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D10996

llvm-svn: 241672
2015-07-08 09:08:53 +00:00
Pavel Labath f805e1905c Fix cmake build after recent JSON changes
I have moved StringExtractor.h into the include/ folder so that it can be properly included by
everyone.

llvm-svn: 241572
2015-07-07 10:08:41 +00:00
Bruce Mitchener a868c13c51 Fix typos
Summary: Fixes more typos.

Reviewers: clayborg

Subscribers: lldb-commits-list

Differential Revision: http://reviews.llvm.org/D10898

llvm-svn: 241289
2015-07-02 18:48:40 +00:00
Ewan Crawford 0c996a9a06 Change search order of target definition files.
Make the python target definition file have highest priority so that we can set 
the remote stub breakpoint pc offset using it.

Reviewers: clayborg
Subscribers: ted, deepak2427, lldb-commits 

Differential revision: http://reviews.llvm.org/D10775

llvm-svn: 241063
2015-06-30 13:08:44 +00:00
Greg Clayton 2e59d4fffe More packet reduction when debugging with GDB server.
- Avoid sending the qfThreadInfo, qsThreadInfo packets if we have a stop reply packet with the threads already (save 2 round trip packets)
- Include the qname, qserial and qkind in the JSON info
- Report the qname, qserial and qkind to the thread so it can cache it to avoid many packets on MacOSX and iOS
- Don't clear all discoverable settings when we exec, just the ones we need to saves 1-5 packets for each exec.

llvm-svn: 240988
2015-06-29 20:08:51 +00:00
Ewan Crawford 682e842855 XML register info fix
There are a couple of bugs in the XML register info handling which this patch fixes:

+ conflicting variable names in lambda, both capture list and parameters contains a variable called 'name'.

+ prev_reg_num, which sets the register number, should be incremented after each register is processed.

+ Windows errors regarding empty strings and the 'xi:' prefix disappearing from 'xi:include' node name.

Reviewers: clayborg

Subscribers: lldb-commits, deepak2427

Differential Revision: http://reviews.llvm.org/D10731

llvm-svn: 240768
2015-06-26 09:38:27 +00:00
Greg Clayton 358cf1ea30 Resubmitting 240466 after fixing the linux test suite failures.
A few extras were fixed

- Symbol::GetAddress() now returns an Address object, not a reference. There were places where people were accessing the address of a symbol when the symbol's value wasn't an address symbol. On MacOSX, undefined symbols have a value zero and some places where using the symbol's address and getting an absolute address of zero (since an Address object with no section and an m_offset whose value isn't LLDB_INVALID_ADDRESS is considered an absolute address). So fixing this required some changes to make sure people were getting what they expected. 
- Since some places want to access the address as a reference, I added a few new functions to symbol:
    Address &Symbol::GetAddressRef();
    const Address &Symbol::GetAddressRef() const;

Linux test suite passes just fine now.

<rdar://problem/21494354>

llvm-svn: 240702
2015-06-25 21:46:34 +00:00
Ewan Crawford aa7eda7a9e Proper handling of QNonStop packet response.
Turn non-stop mode off if reply to QNonStop packet isn't an OK.

llvm-svn: 240546
2015-06-24 15:14:26 +00:00
Greg Clayton 0b90be1c4f Implement the "qSymbol" packet in order to be able to read queue information in debugserver and return the info in the stop reply packets.
A "qSymbol::" is sent when shared libraries have been loaded by hooking into the Process::ModulesDidLoad() function from within ProcessGDBRemote. This function was made virtual so that the ProcessGDBRemote version is called, which then first calls the Process::ModulesDidLoad(), and then it queries for any symbol lookups that the remote GDB server might want to do.

This allows debugserver to request the "dispatch_queue_offsets" symbol so that it can read the queue name, queue kind and queue serial number and include this data as part of the stop reply packet. Previously each thread would have to do 3 memory reads in order to read the queue name.

This is part of reducing the number of packets that are sent between LLDB and the remote GDB server.

<rdar://problem/21494354>

llvm-svn: 240466
2015-06-23 21:27:50 +00:00
Ewan Crawford 76df2881ba Add handling of async notify packets
This patch adds a listener to the AynscThread in ProcessGDBRemote, specifically for dealing with any async notification packets.

From the broadcast our listener receives we can process the notify packet from the event data. A handler function then sets the thread stop info from this packet, and updates lldb by setting the process private state to stopped. Allowing the async thread to go back to sleep and getting the main thread to handle the implications of a state change.

When sending a vCont in nonstop mode we also get a different reply from all-stop mode, an OK response as opposed to a stop reply. So a condition is added to handle this and set the process state without the stop-reply data.

Reviewers: clayborg

Subscribers: lldb-commits, labath, ted, aidan.dodds, deepak2427

Differential Revision: http://reviews.llvm.org/D10544

llvm-svn: 240397
2015-06-23 12:32:06 +00:00
Chaoren Lin 7a30608026 Revert "Reduced packet counts to the remote GDB server where possible."
This reverts commit 0cc0745ea9c68d7fdcadc9904cee3f13c96dae60.

Due to breakage on Linux build bot:

http://lab.llvm.org:8011/builders/lldb-x86_64-ubuntu-14.04-cmake/builds/3436

llvm-svn: 240371
2015-06-23 03:17:01 +00:00
Greg Clayton ffb2d44ab9 Reduced packet counts to the remote GDB server where possible.
We have been working on reducing the packet count that is sent between LLDB and the debugserver on MacOSX and iOS. Our approach to this was to reduce the packets required when debugging multiple threads. We currently make one qThreadStopInfoXXXX call (where XXXX is the thread ID in hex) per thread except the thread that stopped with a stop reply packet. In order to implement multiple thread infos in a single reply, we need to use structured data, which means JSON. The new jThreadsInfo packet will attempt to retrieve all thread infos in a single packet. The data is very similar to the stop reply packets, but packaged in JSON and uses JSON arrays where applicable. The JSON output looks like:


[
  { "tid":1580681,
    "metype":6,
    "medata":[2,0],
    "reason":"exception",
    "qaddr":140735118423168,
    "registers": {
      "0":"8000000000000000",
      "1":"0000000000000000",
      "2":"20fabf5fff7f0000",
      "3":"e8f8bf5fff7f0000",
      "4":"0100000000000000",
      "5":"d8f8bf5fff7f0000",
      "6":"b0f8bf5fff7f0000",
      "7":"20f4bf5fff7f0000",
      "8":"8000000000000000",
      "9":"61a8db78a61500db",
      "10":"3200000000000000",
      "11":"4602000000000000",
      "12":"0000000000000000",
      "13":"0000000000000000",
      "14":"0000000000000000",
      "15":"0000000000000000",
      "16":"960b000001000000",
      "17":"0202000000000000",
      "18":"2b00000000000000",
      "19":"0000000000000000",
      "20":"0000000000000000"},
    "memory":[
      {"address":140734799804592,"bytes":"c8f8bf5fff7f0000c9a59e8cff7f0000"},
      {"address":140734799804616,"bytes":"00000000000000000100000000000000"}
    ]
  }
]

It contains an array of dicitionaries with all of the key value pairs that are normally in the stop reply packet. Including the expedited registers. Notice that is also contains expedited memory in the "memory" key. Any values in this memory will get included in a new L1 cache in lldb_private::Process where if a memory read request is made and that memory request fits into one of the L1 memory cache blocks, it will use that memory data. If a memory request fails in the L1 cache, it will fall back to the L2 cache which is the same block sized caching we were using before these changes. This allows a process to expedite memory that you are likely to use and it reduces packet count. On MacOSX with debugserver, we expedite the frame pointer backchain for a thread (up to 256 entries) by reading 2 pointers worth of bytes at the frame pointer (for the previous FP and PC), and follow the backchain. Most backtraces on MacOSX and iOS now don't require us to read any memory!

We will try these packets out and if successful, we should port these to lldb-server in the near future. 

<rdar://problem/21494354>

llvm-svn: 240354
2015-06-22 23:12:45 +00:00
Jason Molenda 91ffe0a570 Add a new wart, I mean feature, on to gdb-remote protocol: compression.
For some communication channels, sending large packets can be very 
slow.  In those cases, it may be faster to compress the contents of
the packet on the target device and decompress it on the debug host
system.  For instance, communicating with a device using something
like Bluetooth may be an environment where this tradeoff is a good one.

This patch adds a new field to the response to the "qSupported" packet
(which returns a "qXfer:features:" response) -- SupportedCompressions
and DefaultCompressionMinSize.  These tell you what the remote
stub can support.

lldb, if it wants to enable compression and can handle one of those 
algorithms, it can send a QEnableCompression packet specifying the
algorithm and optionally the minimum packet size to use compression
on.  lldb may have better knowledge about the best tradeoff for
a given communication channel.

I added support to debugserver an lldb to use the zlib APIs
(if -DHAVE_LIBZ=1 is in CFLAGS and -lz is in LDFLAGS) and the
libcompression APIs on Mac OS X 10.11 and later 
(if -DHAVE_LIBCOMPRESSION=1).  libz "zlib-deflate" compression.
libcompression can support deflate, lz4, lzma, and a proprietary
lzfse algorithm.  libcompression has been hand-tuned for Apple
hardware so it should be preferred if available.

debugserver currently only adds the SupportedCompressions when
it is being run on an Apple watch (TARGET_OS_WATCH).  Comment
that #if out from RNBRemote.cpp if you want to enable it to
see how it works.  I haven't tested this on a native system
configuration but surely it will be slower to compress & decompress
the packets in a same-system debug session.

I haven't had a chance to add support for this to 
GDBRemoteCommunciationServer.cpp yet.

<rdar://problem/21090180> 

llvm-svn: 240066
2015-06-18 21:46:06 +00:00
Tamas Berghammer 783bfc8caa Fetch object file load address if it isn't specified by the linker
Differential revision: http://reviews.llvm.org/D10490

llvm-svn: 240052
2015-06-18 20:43:56 +00:00
Mohit K. Bhakkad 3579996399 [LLDB][MIPS] Hardware Watchpoints for MIPS
Reviewers: clayborg, jingham.
Subscribers: jaydeep, bhushan, dsanders, sagar, lldb-commits.
Differential Revision: http://reviews.llvm.org/D9142

llvm-svn: 239991
2015-06-18 04:53:18 +00:00
Ewan Crawford fab40d3911 Add Read Thread to GDBRemoteCommunication
In order to support asynchronous notifications for non-stop mode this patch adds a packet read thread. This is done by implementing AppendBytesToCache() from the communications class, which continually reads packets into a packet queue. To initialize this thread StartReadThread() must be called by the client, so since llgs and platform tools use the GBDRemoteCommunicatos code they must also call this function as well as ProcessGDBRemote.

When the read thread detects an async notify packet it broadcasts this event, where the matching listener will be added in the next non-stop patch.

Packets are now accessed by calling ReadPacket() which pops a packet from the queue, instead of using WaitForPacketWithTimeoutMicroSecondsNoLock()

Reviewers: vharron, clayborg

Subscribers: lldb-commits, labath, ted, domipheus, deepak2427 

Differential Revision: http://reviews.llvm.org/D10085

llvm-svn: 239824
2015-06-16 15:50:18 +00:00
Chaoren Lin 44145d79cc Working directory FileSpec should use remote path syntax to display correctly.
Summary: Depends on D9728.

Reviewers: ovyalov, zturner, clayborg

Reviewed By: clayborg

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D9806

llvm-svn: 238605
2015-05-29 19:52:37 +00:00
Chaoren Lin d3173f34e8 Refactor many file functions to use FileSpec over strings.
Summary:
This should solve the issue of sending denormalized paths over gdb-remote
if we stick to GetPath(false) in GDBRemoteCommunicationClient, and let the
server handle any denormalization.

Reviewers: ovyalov, zturner, vharron, clayborg

Reviewed By: clayborg

Subscribers: tberghammer, emaste, lldb-commits

Differential Revision: http://reviews.llvm.org/D9728

llvm-svn: 238604
2015-05-29 19:52:29 +00:00
Zachary Turner 1124045ac7 Don't #include "lldb-python.h" from anywhere.
Since interaction with the python interpreter is moving towards
being more isolated, we won't be able to include this header from
normal files anymore, all includes of it should be localized to
the python library which will live under source/bindings/API/Python
after a future patch.

None of the files that were including this header actually depended
on it anyway, so it was just a dead include in every single instance.

llvm-svn: 238581
2015-05-29 17:41:47 +00:00
Pavel Labath c4e25c9648 Report inferior SIGSEGV as a signal instead of an exception on linux
Summary:
Previously, we reported inferior receiving SIGSEGV (or SIGILL, SIGFPE, SIGBUS) as an "exception"
to LLDB, presumably to match OSX behaviour. Beside the fact that we were basically lying to the
user, this was also causing problems with inferiors which handle SIGSEGV by themselves, since
LLDB was unable to reinject this signal back into the inferior.

This commit changes LLGS to report SIGSEGV as a signal. This has necessitated some changes in the
test-suite, which had previously used eStopReasonException to locate threads that crashed. Now it
uses platform-specific logic, which in the case of linux searches for eStopReasonSignaled with
signal=SIGSEGV.

I have also added the ability to set the description of StopInfoUnixSignal using the description
field of the gdb-remote packet. The linux stub uses this to display additional information about
the segfault (invalid address, address access protected, etc.).

Test Plan: All tests pass on linux and osx.

Reviewers: ovyalov, clayborg, emaste

Subscribers: emaste, lldb-commits

Differential Revision: http://reviews.llvm.org/D10057

llvm-svn: 238549
2015-05-29 10:13:03 +00:00
Ying Chen 5340683e7a Add '+' sign at the end of echo package
Summary:
-Fix lldb test failures introduced by r238530
-This fix TestGdbRemoteAuxvSupport.py and TestLldbGdbServer.py

Test Plan:
./dotest -p TestGdbRemoteAuxvSupport.py
./dotest -p TestLldbGdbServer.py

Reviewers: clayborg, chaoren, vharron

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D10116

llvm-svn: 238535
2015-05-29 01:02:07 +00:00
Greg Clayton 420562aa82 Add support for the qEcho command to lldb-server in the common packets.
llvm-svn: 238533
2015-05-29 00:15:15 +00:00
Greg Clayton b30c50c8fa Add a new "qEcho" packet with the following format:
qEcho:%s

where '%s' is any valid string. The response to this packet is the exact packet itself with no changes, just reply with what you received!

This will help us to recover from packets timing out much more gracefully. Currently if a packet times out, LLDB quickly will hose up the debug session. For example, if we send a "abc" packet and we expect "ABC" back in response, but the "abc" command takes longer than the current timeout value this will happen:


--> "abc"
<-- <<<error: timeout>>>

Now we want to send "def" and get "DEF" back:

--> "def"
<-- "ABC"

We got the wrong response for the "def" packet because we didn't sync up with the server to clear any current responses from previously issues commands.

The fix is to modify GDBRemoteCommunication::WaitForPacketWithTimeoutMicroSecondsNoLock() so that when it gets a timeout, it syncs itself up with the client by sending a "qEcho:%u" where %u is an increasing integer, one for each time we timeout. We then wait for 3 timeout periods to sync back up. So the above "abc" session would look like:

--> "abc"
<-- <<<error: timeout>>> 1 second
--> "qEcho:1"
<-- <<<error: timeout>>> 1 second
<-- <<<error: timeout>>> 1 second
<-- "abc"
<-- "qEcho:1"

The first timeout is from trying to get the response, then we know we timed out and we send the "qEcho:1" packet and wait for 3 timeout periods to get back in sync knowing that we might actually get the response for the "abc" packet in the mean time...

In this case we would actually succeed in getting the response for "abc". But lets say the remote GDB server is deadlocked and will never response, it would look like:

--> "abc"
<-- <<<error: timeout>>> 1 second
--> "qEcho:1"
<-- <<<error: timeout>>> 1 second
<-- <<<error: timeout>>> 1 second
<-- <<<error: timeout>>> 1 second

We then disconnect and say we lost connection.

We might also have a bad GDB server that just dropped the "abc" packet on the floor. We can still recover in this case and it would look like:

--> "abc"
<-- <<<error: timeout>>> 1 second
--> "qEcho:1"
<-- "qEcho:1"

Then we know our remote GDB server is still alive and well, and it just dropped the "abc" response on the floor and we can continue to debug.

<rdar://problem/21082939>

llvm-svn: 238530
2015-05-29 00:01:55 +00:00
Ewan Crawford 9aa2da0025 Change ProcessGDBRemote last stop packet to a container.
In ProcessGDBRemote we currently have a single packet, m_last_stop_packet, used to set the thread stop info.
However in non-stop mode we can receive several stop reply packets in a sequence for different threads. As a result we need to use a container to hold them before they are processed.

This patch also changes the return type of CheckPacket() so we can detect async notification packets.

Reviewers: clayborg

Subscribers: labath, ted, deepak2427, lldb-commits

Differential Revision: http://reviews.llvm.org/D9853

llvm-svn: 238323
2015-05-27 14:12:34 +00:00
Tamas Berghammer 9c9ecce077 Make log options uniform betwwen lldb-platform and lldb-gdbserver
This change also get rid of an unused Debugger instance in
GDBRemoteCommunicationServerLLGS and the command interpreter from
lldb-platform what was used only for enabling logging.

Differential revision: http://reviews.llvm.org/D9876

llvm-svn: 238319
2015-05-27 13:34:04 +00:00
Greg Clayton d04f0edad9 Added XML to the host layer.
We know have on API we should use for all XML within LLDB in XML.h. This API will be easy back the XML parsing by different libraries in case libxml2 doesn't work on all platforms. It also allows the only place for #ifdef ...XML... to be in XML.h and XML.cpp. The API is designed so it will still compile with or without XML support and there is a static function "bool XMLDocument::XMLEnabled()" that can be called to see if XML is currently supported. All APIs will return errors, false, or nothing when XML isn't enabled.

Converted all locations that used XML over to using the host XML implementation.

Added target.xml support to debugserver. Extended the XML register format to work for LLDB by including extra attributes and elements where needed. This allows the target.xml to replace the qRegisterInfo packets and allows us to fetch all register info in a single packet.

<rdar://problem/21090173>

llvm-svn: 238224
2015-05-26 18:00:51 +00:00
Greg Clayton 5df78fa35b Did some cleanup to stop us from leaking Pipe file descriptors.
The main issue was the Communication::Disconnect() was calling its Connection::Disconnect() but this wouldn't release the pipes that the ConnectionFileDescriptor was using. We also have someone that is holding a strong reference to the Process so that when you re-run, target replaces its m_process_sp, but it doesn't get destructed because someone has a strong reference to it. I need to track that down. But, even if we have a strong reference to the a process that is outstanding, we need to call Process::Finalize() to have it release as much of its resources as possible to avoid memory bloat. 

Removed the ProcessGDBRemote::SetExitStatus() override and replaced it with ProcessGDBRemote::DidExit().

Now we aren't leaking file descriptors and the stand alone test suite should run much better.

llvm-svn: 238089
2015-05-23 03:54:53 +00:00
Oleksiy Vyalov 755d58a463 Use target's SIGSTOP and SIGINT when making decision about continue after async packet.
http://reviews.llvm.org/D9857

llvm-svn: 238068
2015-05-22 23:14:39 +00:00
Greg Clayton e034a04e4f Added a new command in ProcessGDBRemote that can figure out the performance characterisitics of your GDB remote server.
To addess this, attach to any GDB server and when stopped type:

(lldb) process plugin packet speed-test

The default will send a variety of packets with different amounts of data to send/receive and print the performance of each packet type:

Testing sending 1000 packets of various sizes:
qSpeedTest(send=0      , recv=0      ) in 0.057837000 sec for  17289.97 packets/sec (  0.057837 ms per packet) with standard deviation of   0.007705 ms
qSpeedTest(send=0      , recv=4      ) in 0.056162000 sec for  17805.63 packets/sec (  0.056162 ms per packet) with standard deviation of   0.004439 ms
qSpeedTest(send=0      , recv=8      ) in 0.057687000 sec for  17334.93 packets/sec (  0.057687 ms per packet) with standard deviation of   0.008135 ms
qSpeedTest(send=0      , recv=16     ) in 0.058547000 sec for  17080.29 packets/sec (  0.058547 ms per packet) with standard deviation of   0.005884 ms
qSpeedTest(send=0      , recv=32     ) in 0.058289000 sec for  17155.89 packets/sec (  0.058289 ms per packet) with standard deviation of   0.004057 ms
qSpeedTest(send=0      , recv=64     ) in 0.061324000 sec for  16306.83 packets/sec (  0.061324 ms per packet) with standard deviation of   0.010838 ms
qSpeedTest(send=0      , recv=128    ) in 0.065688000 sec for  15223.48 packets/sec (  0.065688 ms per packet) with standard deviation of   0.006997 ms
qSpeedTest(send=0      , recv=256    ) in 0.070621000 sec for  14160.09 packets/sec (  0.070621 ms per packet) with standard deviation of   0.006188 ms
qSpeedTest(send=0      , recv=512    ) in 0.086738000 sec for  11528.97 packets/sec (  0.086738 ms per packet) with standard deviation of   0.007867 ms
qSpeedTest(send=0      , recv=1024   ) in 0.146375000 sec for   6831.77 packets/sec (  0.146375 ms per packet) with standard deviation of   0.010313 ms
qSpeedTest(send=4      , recv=0      ) in 0.057807000 sec for  17298.94 packets/sec (  0.057807 ms per packet) with standard deviation of   0.009702 ms
....

It will then also use various sizes to receive 4MB of data from the GDB server and print out the stats:

Testing receiving 4.0MB of data using varying receive packet sizes:
qSpeedTest(send=0      , recv=32     ) 131072 packets needed to receive 4.0MB in 7.721290000 sec for 0.518048 MB/sec for  16975.40 packets/sec (  0.058909 ms per packet)
qSpeedTest(send=0      , recv=64     )  65536 packets needed to receive 4.0MB in 4.029236000 sec for 0.992744 MB/sec for  16265.12 packets/sec (  0.061481 ms per packet)
qSpeedTest(send=0      , recv=128    )  32768 packets needed to receive 4.0MB in 2.233854000 sec for 1.790627 MB/sec for  14668.82 packets/sec (  0.068172 ms per packet)
qSpeedTest(send=0      , recv=256    )  16384 packets needed to receive 4.0MB in 1.160024000 sec for 3.448204 MB/sec for  14123.84 packets/sec (  0.070802 ms per packet)
qSpeedTest(send=0      , recv=512    )   8192 packets needed to receive 4.0MB in 0.701603000 sec for 5.701230 MB/sec for  11676.12 packets/sec (  0.085645 ms per packet)
qSpeedTest(send=0      , recv=1024   )   4096 packets needed to receive 4.0MB in 0.596786000 sec for 6.702570 MB/sec for   6863.43 packets/sec (  0.145700 ms per packet)

There is a JSON mode so we can use this in the test suite to track GDB server performance for each platform:

(lldb) process plugin packet speed-test --json
{ "packet_speeds" : {
    "num_packets" : 1000,
    "results" : [
     {"send_size" :      0, "recv_size" :      0, "total_time_nsec" :     64516000, "standard_deviation_nsec" :     20566 },
     {"send_size" :      0, "recv_size" :      4, "total_time_nsec" :     59648000, "standard_deviation_nsec" :     10493 },
     {"send_size" :      0, "recv_size" :      8, "total_time_nsec" :     56894000, "standard_deviation_nsec" :      5480 },
     {"send_size" :      0, "recv_size" :     16, "total_time_nsec" :     59422000, "standard_deviation_nsec" :      6557 },
     {"send_size" :      0, "recv_size" :     32, "total_time_nsec" :     61159000, "standard_deviation_nsec" :     12384 },
     {"send_size" :      0, "recv_size" :     64, "total_time_nsec" :     61386000, "standard_deviation_nsec" :      9208 },
     {"send_size" :      0, "recv_size" :    128, "total_time_nsec" :     64768000, "standard_deviation_nsec" :      4737 },
     {"send_size" :      0, "recv_size" :    256, "total_time_nsec" :     71046000, "standard_deviation_nsec" :      5904 },
     {"send_size" :      0, "recv_size" :    512, "total_time_nsec" :     87233000, "standard_deviation_nsec" :      8967 },
     {"send_size" :      0, "recv_size" :   1024, "total_time_nsec" :    146629000, "standard_deviation_nsec" :      9526 },
     {"send_size" :      4, "recv_size" :      0, "total_time_nsec" :     57131000, "standard_deviation_nsec" :      7884 },
     {"send_size" :      4, "recv_size" :      4, "total_time_nsec" :     56772000, "standard_deviation_nsec" :      6064 },
     {"send_size" :      4, "recv_size" :      8, "total_time_nsec" :     57450000, "standard_deviation_nsec" :      6341 },
     {"send_size" :      4, "recv_size" :     16, "total_time_nsec" :     58279000, "standard_deviation_nsec" :      5998 },
     {"send_size" :      4, "recv_size" :     32, "total_time_nsec" :     59995000, "standard_deviation_nsec" :      6294 },
     {"send_size" :      4, "recv_size" :     64, "total_time_nsec" :     61632000, "standard_deviation_nsec" :      7838 },
     {"send_size" :      4, "recv_size" :    128, "total_time_nsec" :     66535000, "standard_deviation_nsec" :      8026 },
     {"send_size" :      4, "recv_size" :    256, "total_time_nsec" :     72754000, "standard_deviation_nsec" :      9519 },
     {"send_size" :      4, "recv_size" :    512, "total_time_nsec" :     87072000, "standard_deviation_nsec" :      9268 },
     {"send_size" :      4, "recv_size" :   1024, "total_time_nsec" :    147221000, "standard_deviation_nsec" :      9702 },
     {"send_size" :      8, "recv_size" :      0, "total_time_nsec" :     57900000, "standard_deviation_nsec" :      7356 },
     {"send_size" :      8, "recv_size" :      4, "total_time_nsec" :     58116000, "standard_deviation_nsec" :      7630 },
     {"send_size" :      8, "recv_size" :      8, "total_time_nsec" :     57745000, "standard_deviation_nsec" :      8541 },
     {"send_size" :      8, "recv_size" :     16, "total_time_nsec" :     59091000, "standard_deviation_nsec" :      7851 },
     {"send_size" :      8, "recv_size" :     32, "total_time_nsec" :     59943000, "standard_deviation_nsec" :      6761 },
     {"send_size" :      8, "recv_size" :     64, "total_time_nsec" :     62097000, "standard_deviation_nsec" :      8580 },
     {"send_size" :      8, "recv_size" :    128, "total_time_nsec" :     69942000, "standard_deviation_nsec" :     16645 },
     {"send_size" :      8, "recv_size" :    256, "total_time_nsec" :     72927000, "standard_deviation_nsec" :     11031 },
     {"send_size" :      8, "recv_size" :    512, "total_time_nsec" :     87221000, "standard_deviation_nsec" :      8002 },
     {"send_size" :      8, "recv_size" :   1024, "total_time_nsec" :    148696000, "standard_deviation_nsec" :     10383 },
     {"send_size" :     16, "recv_size" :      0, "total_time_nsec" :     59890000, "standard_deviation_nsec" :     15160 },
     {"send_size" :     16, "recv_size" :      4, "total_time_nsec" :     56664000, "standard_deviation_nsec" :      4650 },
     {"send_size" :     16, "recv_size" :      8, "total_time_nsec" :     57574000, "standard_deviation_nsec" :      7787 },
     {"send_size" :     16, "recv_size" :     16, "total_time_nsec" :     59312000, "standard_deviation_nsec" :      8104 },
     {"send_size" :     16, "recv_size" :     32, "total_time_nsec" :     59764000, "standard_deviation_nsec" :      7496 },
     {"send_size" :     16, "recv_size" :     64, "total_time_nsec" :     61644000, "standard_deviation_nsec" :      8331 },
     {"send_size" :     16, "recv_size" :    128, "total_time_nsec" :     66476000, "standard_deviation_nsec" :      9251 },
     {"send_size" :     16, "recv_size" :    256, "total_time_nsec" :     72386000, "standard_deviation_nsec" :      8627 },
     {"send_size" :     16, "recv_size" :    512, "total_time_nsec" :     87810000, "standard_deviation_nsec" :     12318 },
     {"send_size" :     16, "recv_size" :   1024, "total_time_nsec" :    146918000, "standard_deviation_nsec" :     11595 },
     {"send_size" :     32, "recv_size" :      0, "total_time_nsec" :     56493000, "standard_deviation_nsec" :      6577 },
     {"send_size" :     32, "recv_size" :      4, "total_time_nsec" :     57069000, "standard_deviation_nsec" :      5931 },
     {"send_size" :     32, "recv_size" :      8, "total_time_nsec" :     57563000, "standard_deviation_nsec" :      8157 },
     {"send_size" :     32, "recv_size" :     16, "total_time_nsec" :     59694000, "standard_deviation_nsec" :      6932 },
     {"send_size" :     32, "recv_size" :     32, "total_time_nsec" :     60852000, "standard_deviation_nsec" :      8010 },
     {"send_size" :     32, "recv_size" :     64, "total_time_nsec" :     61926000, "standard_deviation_nsec" :      8372 },
     {"send_size" :     32, "recv_size" :    128, "total_time_nsec" :     66734000, "standard_deviation_nsec" :      8047 },
     {"send_size" :     32, "recv_size" :    256, "total_time_nsec" :     72000000, "standard_deviation_nsec" :      8103 },
     {"send_size" :     32, "recv_size" :    512, "total_time_nsec" :     88268000, "standard_deviation_nsec" :     12289 },
     {"send_size" :     32, "recv_size" :   1024, "total_time_nsec" :    147946000, "standard_deviation_nsec" :     12122 },
     {"send_size" :     64, "recv_size" :      0, "total_time_nsec" :     58126000, "standard_deviation_nsec" :      5895 },
     {"send_size" :     64, "recv_size" :      4, "total_time_nsec" :     58927000, "standard_deviation_nsec" :      8933 },
     {"send_size" :     64, "recv_size" :      8, "total_time_nsec" :     58163000, "standard_deviation_nsec" :      6663 },
     {"send_size" :     64, "recv_size" :     16, "total_time_nsec" :     59901000, "standard_deviation_nsec" :      8340 },
     {"send_size" :     64, "recv_size" :     32, "total_time_nsec" :     60365000, "standard_deviation_nsec" :      6319 },
     {"send_size" :     64, "recv_size" :     64, "total_time_nsec" :     61776000, "standard_deviation_nsec" :      7461 },
     {"send_size" :     64, "recv_size" :    128, "total_time_nsec" :     66984000, "standard_deviation_nsec" :      6810 },
     {"send_size" :     64, "recv_size" :    256, "total_time_nsec" :     73913000, "standard_deviation_nsec" :      8826 },
     {"send_size" :     64, "recv_size" :    512, "total_time_nsec" :     88134000, "standard_deviation_nsec" :      8356 },
     {"send_size" :     64, "recv_size" :   1024, "total_time_nsec" :    146932000, "standard_deviation_nsec" :      7571 },
     {"send_size" :    128, "recv_size" :      0, "total_time_nsec" :     57616000, "standard_deviation_nsec" :      6158 },
     {"send_size" :    128, "recv_size" :      4, "total_time_nsec" :     59091000, "standard_deviation_nsec" :      7458 },
     {"send_size" :    128, "recv_size" :      8, "total_time_nsec" :     60263000, "standard_deviation_nsec" :     11999 },
     {"send_size" :    128, "recv_size" :     16, "total_time_nsec" :     59238000, "standard_deviation_nsec" :      6102 },
     {"send_size" :    128, "recv_size" :     32, "total_time_nsec" :     60783000, "standard_deviation_nsec" :      6244 },
     {"send_size" :    128, "recv_size" :     64, "total_time_nsec" :     62975000, "standard_deviation_nsec" :      8947 },
     {"send_size" :    128, "recv_size" :    128, "total_time_nsec" :     65742000, "standard_deviation_nsec" :      5907 },
     {"send_size" :    128, "recv_size" :    256, "total_time_nsec" :     72402000, "standard_deviation_nsec" :      6601 },
     {"send_size" :    128, "recv_size" :    512, "total_time_nsec" :     87457000, "standard_deviation_nsec" :      9004 },
     {"send_size" :    128, "recv_size" :   1024, "total_time_nsec" :    148412000, "standard_deviation_nsec" :     10532 },
     {"send_size" :    256, "recv_size" :      0, "total_time_nsec" :     58705000, "standard_deviation_nsec" :      7274 },
     {"send_size" :    256, "recv_size" :      4, "total_time_nsec" :     58818000, "standard_deviation_nsec" :      5453 },
     {"send_size" :    256, "recv_size" :      8, "total_time_nsec" :     59451000, "standard_deviation_nsec" :      6926 },
     {"send_size" :    256, "recv_size" :     16, "total_time_nsec" :     60237000, "standard_deviation_nsec" :      5781 },
     {"send_size" :    256, "recv_size" :     32, "total_time_nsec" :     61456000, "standard_deviation_nsec" :      5591 },
     {"send_size" :    256, "recv_size" :     64, "total_time_nsec" :     62615000, "standard_deviation_nsec" :      7588 },
     {"send_size" :    256, "recv_size" :    128, "total_time_nsec" :     68554000, "standard_deviation_nsec" :      7766 },
     {"send_size" :    256, "recv_size" :    256, "total_time_nsec" :     74557000, "standard_deviation_nsec" :      8748 },
     {"send_size" :    256, "recv_size" :    512, "total_time_nsec" :     87929000, "standard_deviation_nsec" :      9510 },
     {"send_size" :    256, "recv_size" :   1024, "total_time_nsec" :    148522000, "standard_deviation_nsec" :     11394 },
     {"send_size" :    512, "recv_size" :      0, "total_time_nsec" :     59697000, "standard_deviation_nsec" :      7825 },
     {"send_size" :    512, "recv_size" :      4, "total_time_nsec" :     59427000, "standard_deviation_nsec" :      5706 },
     {"send_size" :    512, "recv_size" :      8, "total_time_nsec" :     59538000, "standard_deviation_nsec" :      6863 },
     {"send_size" :    512, "recv_size" :     16, "total_time_nsec" :     61139000, "standard_deviation_nsec" :      7645 },
     {"send_size" :    512, "recv_size" :     32, "total_time_nsec" :     62203000, "standard_deviation_nsec" :      7985 },
     {"send_size" :    512, "recv_size" :     64, "total_time_nsec" :     62577000, "standard_deviation_nsec" :      8118 },
     {"send_size" :    512, "recv_size" :    128, "total_time_nsec" :     68722000, "standard_deviation_nsec" :     10581 },
     {"send_size" :    512, "recv_size" :    256, "total_time_nsec" :     74290000, "standard_deviation_nsec" :      8931 },
     {"send_size" :    512, "recv_size" :    512, "total_time_nsec" :     88635000, "standard_deviation_nsec" :      7771 },
     {"send_size" :    512, "recv_size" :   1024, "total_time_nsec" :    149589000, "standard_deviation_nsec" :     11456 },
     {"send_size" :   1024, "recv_size" :      0, "total_time_nsec" :     63243000, "standard_deviation_nsec" :      6331 },
     {"send_size" :   1024, "recv_size" :      4, "total_time_nsec" :     64381000, "standard_deviation_nsec" :      8372 },
     {"send_size" :   1024, "recv_size" :      8, "total_time_nsec" :     63481000, "standard_deviation_nsec" :      5608 },
     {"send_size" :   1024, "recv_size" :     16, "total_time_nsec" :     65549000, "standard_deviation_nsec" :      8826 },
     {"send_size" :   1024, "recv_size" :     32, "total_time_nsec" :     65485000, "standard_deviation_nsec" :      6822 },
     {"send_size" :   1024, "recv_size" :     64, "total_time_nsec" :     67125000, "standard_deviation_nsec" :      9829 },
     {"send_size" :   1024, "recv_size" :    128, "total_time_nsec" :     72680000, "standard_deviation_nsec" :      7641 },
     {"send_size" :   1024, "recv_size" :    256, "total_time_nsec" :     79206000, "standard_deviation_nsec" :      9854 },
     {"send_size" :   1024, "recv_size" :    512, "total_time_nsec" :     92418000, "standard_deviation_nsec" :      9107 },
     {"send_size" :   1024, "recv_size" :   1024, "total_time_nsec" :    152392000, "standard_deviation_nsec" :     11124 }
    ]
  },
  "download_speed" : {
    "byte_size" : 4194304,
    "results" : [
     {"send_size" :      0, "recv_size" :     32, "total_time_nsec" :   7735630000 },
     {"send_size" :      0, "recv_size" :     64, "total_time_nsec" :   3985169000 },
     {"send_size" :      0, "recv_size" :    128, "total_time_nsec" :   2128791000 },
     {"send_size" :      0, "recv_size" :    256, "total_time_nsec" :   1172077000 },
     {"send_size" :      0, "recv_size" :    512, "total_time_nsec" :    703833000 },
     {"send_size" :      0, "recv_size" :   1024, "total_time_nsec" :    594966000 }
    ]
  }
}

llvm-svn: 237953
2015-05-21 20:52:06 +00:00
Siva Chandra 8fd94c9e68 [GDBRemoteCommunicationClient] Increase timeout for qfProcessInfo packet.
Summary:
The test in TestPlatformCommand which runs "platform process list" has
been timing out for Android when running running dosep.py with
LLDB_TEST_THREADS=8. This patch increases the packet timeout to a large
value of 1min to accommodate the long time required for a response for
the qfProcessInfo packet on Android.

Test Plan: LLDB_TEST_THREADS=8 ./dosep.py on Android.

Reviewers: chaoren

Reviewed By: chaoren

Subscribers: tberghammer, lldb-commits

Differential Revision: http://reviews.llvm.org/D9866

llvm-svn: 237752
2015-05-20 00:30:31 +00:00
Pavel Labath 48fca3b982 Fix StopInfoWatchpoint handling after r237411
r237411 exposed the following issue: ProcessGDBRemote used the description field in the
stop-reply to set the description of the StopInfo. In the case of watchpoints, the packet
description contains the raw address that got hit, which is not exactly the information we want
to display to the user as the stop info. Therefore, I have changed the code to use the packet
description only if the StopInfo does not already have a description. This makes the behavior
equivalent to the pre-r237411 behavior as then the SetDecription call got ignored for
watchpoints.

llvm-svn: 237436
2015-05-15 10:14:51 +00:00
Ilia K d50ea2fc15 Fix a few compile warnings
llvm-svn: 237425
2015-05-15 09:15:27 +00:00
Zachary Turner 1aa755ce77 Remove DoAttachToProcessWithId(lldb::pid_t).
There were two versions of DoAttachToprocessWithId.  One that takes
a pid_t, and the other which takes a pid_t and a ProcessAttachInfo.
There were no callers of the former version, and all of the
implementations of this version were simply forwarding calls to
one version or the other.

llvm-svn: 237281
2015-05-13 19:44:44 +00:00
Ewan Crawford 78baa19781 Remote Non-Stop Support
Summary:
 
This patch is the beginnings of support for Non-stop mode in the remote protocol. Letting a user examine stopped threads, while other threads execute freely.

Non-stop mode is enabled using the setting target.non-stop-mode, which sends a QNonStop packet when establishing the remote connection.
Changes are also made to treat the '?' stop reply packet differently in non-stop mode, according to spec https://sourceware.org/gdb/current/onlinedocs/gdb/Remote-Non_002dStop.html#Remote-Non_002dStop.
A setting for querying the remote for default thread on setup is also included.

Handling of '%' async notification packets will be added next.

Reviewers: clayborg

Subscribers: lldb-commits, ADodds, ted, deepak2427

Differential Revision: http://reviews.llvm.org/D9656

llvm-svn: 237239
2015-05-13 09:18:18 +00:00
Vince Harron d7e6a4f2f0 Fixed a ton of gcc compile warnings
Removed some unused variables, added some consts, changed some casts
to const_cast. I don't think any of these changes are very
controversial.

Differential Revision: http://reviews.llvm.org/D9674

llvm-svn: 237218
2015-05-13 00:25:54 +00:00