Commit Graph

1158 Commits

Author SHA1 Message Date
Jason Molenda c7afda5a09 Add support for using armv7 compact unwind information
as an asynchronous unwind plan source.

Two small fixes to the compact unwind dumper tool for
armv7 encodings.

A change to DWARFCallFrameInfo to strip the 0th bit on
addresses in eh_frame sections when armv7.  In the 
clang generated examples I have, the 0th bit is set for
thumb functions and that's causing the unwinder to pick
the wrong function for eh_frame info.

llvm-svn: 271970
2016-06-07 02:19:54 +00:00
Jason Molenda 159ccb49b3 Add armv7 compact unwind printing to the compact-unwind-dumper.c tool
as a prototype for adding armv7 compact unwind reading to lldb.

llvm-svn: 271774
2016-06-04 04:10:15 +00:00
Pavel Labath 23ef3695d4 [cmake] Add ability to customize (and skip) debugserver codesign
Summary:
This adds the ability to customize the debugserver codesign process via cmake cache variable. The
user can set the codesign indentity (with the default being the customary lldb_codesign), and if
the identity is set to a empty string, the codesign step is skipped completely.

We needed the last feature to enable building lldb on buildservers which do not have the right
certificates installed.

Reviewers: sas, tberghammer

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D20623

llvm-svn: 270832
2016-05-26 08:38:10 +00:00
Jason Molenda b667c20222 Add support for arm64 compact unwind tables, used on darwin arm64
systems (ios, tvos, watchos).  It's a simple format to use now that
I have i386/x86_64 supported already.

The unwind instructions are only valid at call sites -- that is,
when lldb is unwinding a frame in the middle of the stack.  It
cannot be used for the currently executing frame; it has no information
about prologues/epilogues/etc.

<rdar://problem/12062336> 

llvm-svn: 270658
2016-05-25 04:20:28 +00:00
Jason Molenda 1fec404da0 Check that __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ is defined
before comparing the value of it.
<rdar://problem/26333564> 

llvm-svn: 270015
2016-05-19 02:16:41 +00:00
Enrico Granata 109dd2e2a2 Fix an issue where debugserver would not properly vend OS version information on iOS devices
The __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED macro is only defined on OS X, so the check as written compiled the code out for iOS
The right thing to do is compile the code out for older OSX versions, but leave iOS alone

rdar://26333564

llvm-svn: 270004
2016-05-18 23:59:24 +00:00
Greg Clayton 1059a067f9 Don't crash when a process' task port goes bad.
<rdar://problem/26256049>

llvm-svn: 269373
2016-05-12 22:36:47 +00:00
Saleem Abdulrasool d97dd11f2f debugserver; fix -Wunused-local-typedef, -Wunused-variable warnings
Remove the typedef and local structure which was unused.  Fixes last of the new
clang warnings in the debugserver build.  NFC.

llvm-svn: 268759
2016-05-06 17:33:13 +00:00
Saleem Abdulrasool 247731d4d3 debugserver: fix a couple of -Wmissing-field-initializers warnings
Explicitly provide an initializer for the std::vector in the constructed type.
Addresses -Wmissing-field-initializers warnings from clang.  NFC.

llvm-svn: 268758
2016-05-06 17:33:09 +00:00
Saleem Abdulrasool 4533f7b6e8 debugserver: fix some -Wpessimizing-move warnings
Remove the unnecessary use of std::move to permit the compiler to perform NVRO
instead.  Fixes more warnings from clang.  NFC.

llvm-svn: 268757
2016-05-06 17:33:04 +00:00
Saleem Abdulrasool 2bb818880b debugserver: fix a few -Wcovered-swift-default warnings
Remove a couple of `default` cases from switches which are covered.  This is
beneficial since it would allow the compiler to indicate when a new enum value
is added and the switch is not updated.  Fixes some warnings from clang.  NFC.

llvm-svn: 268756
2016-05-06 17:33:01 +00:00
Saleem Abdulrasool bd7ecf4b02 debugserver: fix some -Wformat-pedantic warnings
Perform explicit casts for the log message to address some `-Wformat-pedantic`
warnings from clang.  NFC.

llvm-svn: 268755
2016-05-06 17:32:58 +00:00
Greg Clayton 7301d39401 debugserver should fflush its log stream in FileLogCallback, now it does.
<rdar://problem/24728287> 

llvm-svn: 268325
2016-05-02 22:53:08 +00:00
Adrian McCarthy f6034c4f3d Don't disable stdin buffering on Windows
Disabling buffering exposes a bug in the MS VS 2015 CRT implementation of fgets, where you sometimes have to hit Enter twice, depending on if the input had an odd or even number of characters.

This was hidden until a few days ago by the Python initialization which was re-enabling buffering on the streams. A few days ago, Enrico make the Python initialization on-demand, which exposed this problem.

llvm-svn: 266384
2016-04-14 23:31:17 +00:00
Pavel Labath bb5c39d79e [Driver] Fix a segfault in signal handlers
Summary:
If we recieve a SIGCONT or SIGTSTP, while the driver is shutting down (which, sometimes, we do,
for reasons which are not completely clear to me), we would crash to due a null pointer
dereference. Guard against this situation.

Reviewers: clayborg

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D18965

llvm-svn: 265958
2016-04-11 16:40:09 +00:00
Chuck Ries da21e98932 -thread-info in lldbmi does not conform to protocol. Should end with current thread id
-thread-info in lldbmi does not conform to protocol. Should end with
current thread id as described here:
https://sourceware.org/gdb/onlinedocs/gdb/GDB_002fMI-Thread-Commands.html#GDB_002fMI-Thread-Commands

When printing all threads, the current thread id should be printed
afterwards.

Example:
-thread-info
     ^done,threads=[
     {id="2",target-id="Thread 0xb7e14b90 (LWP 21257)",
        frame={level="0",addr="0xffffe410",func="__kernel_vsyscall",
                args=[]},state="running"},
     {id="1",target-id="Thread 0xb7e156b0 (LWP 21254)",
        frame={level="0",addr="0x0804891f",func="foo",
                args=[{name="i",value="10"}],
                file="/tmp/a.c",fullname="/tmp/a.c",line="158"},
                state="running"}],
     current-thread-id="1"
     (gdb)

Patch from jacdavis@microsoft.com

Reviewers: zturner, chuckr

Differential Revision: http://reviews.llvm.org/differential/revision/edit/18880/

llvm-svn: 265858
2016-04-08 22:17:53 +00:00
Greg Clayton 830c81d511 Fixed an issue that could cause debugserver to return two stop reply packets ($T packets) for one \x03 interrupt. The problem was that when a \x03 byte is sent to debugserver while the process is running, and up calling:
rnb_err_t
RNBRemote::HandlePacket_stop_process (const char *p)
{
    if (!DNBProcessInterrupt(m_ctx.ProcessID()))
        HandlePacket_last_signal (NULL);
    return rnb_success;
}

In the call to DNBProcessInterrupt we did:

nub_bool_t
DNBProcessInterrupt(nub_process_t pid)
{
    MachProcessSP procSP;
    if (GetProcessSP (pid, procSP))
        return procSP->Interrupt();
    return false;
}

This would always return false. It would cause HandlePacket_stop_process to always call "HandlePacket_last_signal (NULL);" which would send an extra stop reply packet _if_ the process is stopped. On a machine with enough cores, it would call DNBProcessInterrupt(...) and then HandlePacket_last_signal(NULL) so quickly that it will never send out an extra stop reply packet. But if the machine is slow enough or doesn't have enough cores, it could cause the call to HandlePacket_last_signal() to actually succeed and send an extra stop reply packet. This would cause problems up in GDBRemoteCommunicationClient::SendContinuePacketAndWaitForResponse() where it would get the first stop reply packet and then possibly return or execute an async packet. If it returned, then the next packet that was sent will get the second stop reply as its response. If it executes an async packet, the async packet will get the wrong response.

To fix this I did the following:
1 - in debugserver, I fixed "bool MachProcess::Interrupt()" to return true if it sends the signal so we avoid sending the stop reply twice on slower machines
2 - Added a log line to RNBRemote::HandlePacket_stop_process() to say if we ever send an extra stop reply so we will see this in the darwin console output if this does happen
3 - Added response validators to StringExtractorGDBRemote so that we can verify some responses to some packets. 
4 - Added validators to packets that often follow stop reply packets like the "m" packet for memory reads, JSON packets since "jThreadsInfo" is often sent immediately following a stop reply.
5 - Modified GDBRemoteCommunicationClient::SendPacketAndWaitForResponseNoLock() to validate responses. Any "StringExtractorGDBRemote &response" that contains a valid response verifier will verify the response and keep looking for correct responses up to 3 times. This will help us get back on track if we do get extra stop replies. If a StringExtractorGDBRemote does not have a response validator, it will accept any packet in response.
6 - In GDBRemoteCommunicationClient::SendPacketAndWaitForResponse we copy the response validator from the "response" argument over into m_async_response so that if we send the packet by interrupting the running process, we can validate the response we actually get in GDBRemoteCommunicationClient::SendContinuePacketAndWaitForResponse()
7 - Modified GDBRemoteCommunicationClient::SendContinuePacketAndWaitForResponse() to always check for an extra stop reply packet for 100ms when the process is interrupted. We were already doing this because we might interrupt a process with a \x03 packet, yet the process was in the process of stopping due to another reason. This race condition could cause an extra stop reply packet because the GDB remote protocol says if a \x03 packet is sent while the process is stopped, we should send a stop reply packet back. Now we always check for an extra stop reply packet when we manually interrupt a process.

The issue was showing up when our IDE would attempt to set a breakpoint while the process is running and this would happen:

--> \x03
<-- $T<stop reply 1>
--> z0,AAAAA,BB (set breakpoint)
<-- $T<stop reply 1> (incorrect extra stop reply packet)
--> c
<-- OK (response from z0 packet)

Now all packet traffic was off by one response. Since we now have a validator on the response for "z" packets, we do this:

--> \x03
<-- $T<stop reply 1>
--> z0,AAAAA,BB (set breakpoint)
<-- $T<stop reply 1> (Ignore this because this can't be the response to z0 packets)
<-- OK -- (we are back on track as this is a valid response to z0)
...

As time goes on we should add more packet validators.

<rdar://problem/22859505>

llvm-svn: 265086
2016-04-01 00:41:29 +00:00
Pavel Labath 6315e7f000 Revert the "build fix" in r264104
this was needed because lldb-mi temporarily contained references to private lldb symbols
(lldb_private namespace), which it shouldn't have. The situation has since been rectified and
this wasn't the right fix anyway, since it can lead to funny ODR violations.

llvm-svn: 264733
2016-03-29 14:39:10 +00:00
Jason Molenda 5109bfd165 Update the INFOPLIST_FILE setting in the xcode project file
so that the lldb command line binary's version #'s are updated
correctly.
<rdar://problem/25346711> 

llvm-svn: 264353
2016-03-24 22:27:52 +00:00
Sean Callanan cd46960e6b Reverted a change in r264074 that made lldb-mi use lldb_private APIs.
FileSystem::Fopen is a lldb_private API, but lldb-mi uses only the
public API.  Depending on lldb_private APIs makes Xcode builds fail.
I reverted the portion of r264074 that added such a dependency.

llvm-svn: 264113
2016-03-22 22:42:42 +00:00
Siva Chandra c8391975e3 [lldb-mi] Uncomment a line in CMakeLists.txt to make linux build happy.
Reviewers: zturner

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D18377

llvm-svn: 264104
2016-03-22 21:37:56 +00:00
Zachary Turner 190fadcdb2 Unicode support on Win32.
Win32 API calls that are Unicode aware require wide character
strings, but LLDB uses UTF8 everywhere.  This patch does conversions
wherever necessary when passing strings into and out of Win32 API
calls.

Patch by Cameron
Differential Revision: http://reviews.llvm.org/D17107
Reviewed By: zturner, amccarth

llvm-svn: 264074
2016-03-22 17:58:09 +00:00
Sean Callanan 579e70c9b0 Add a DiagnosticManager replace error streams in the expression parser.
We want to do a better job presenting errors that occur when evaluating
expressions. Key to this effort is getting away from a model where all
errors are spat out onto a stream where the client has to take or leave
all of them.

To this end, this patch adds a new class, DiagnosticManager, which
contains errors produced by the compiler or by LLDB as an expression
is created. The DiagnosticManager can dump itself to a log as well as
to a string. Clients will (in the future) be able to filter out the
errors they're interested in by ID or present subsets of these errors
to the user.

This patch is not intended to change the *users* of errors - only to
thread DiagnosticManagers to all the places where streams are used. I
also attempt to standardize our use of errors a bit, removing trailing
newlines and making clients omit 'error:', 'warning:' etc. and instead
pass the Severity flag.

The patch is testsuite-neutral, with modifications to one part of the
MI tests because it relied on "error: error:" being erroneously
printed. This patch fixes the MI variable handling and the testcase.

<rdar://problem/22864976>

llvm-svn: 263859
2016-03-19 00:03:59 +00:00
Zachary Turner 29365da0e8 Delete the custom implementation of signal() on Windows.
The Windows SDK provides a version of signal() that is much more
limited compared to other platforms.  It only supports about 5-6
signal values.  LLDB uses signals for a number of things, most
notably to handle Ctrl+C so we can gracefully shut down.  The
portability solution to this on Windows has been to provide a
hand-rolled implementation of `signal` using the name `signal`
so that you could write code that simply calls signal directly
and it would work.

But this introduces a multiply defined symbol with the builtin
version and depending on how you included header files, you could
get yourself into a situation where you had linker errors.  To
make matters worse, it led to a ton of compiler warnings.  Worst
of all though is that this custom implementation of signal was,
in fact, identical for the purposes of handling Ctrl+C as the
builtin implementation of signal.  So it seems to have literally
not been serving any useful purpose.

This patch deletes all the custom signal() functions for Windows,
and includes the signal.h system header, so that any calls to
signal now go to the actual version provided by the Windows SDK.

Differential Revision: http://reviews.llvm.org/D18287

llvm-svn: 263858
2016-03-18 23:47:48 +00:00
Greg Clayton 5ba3d3e632 Added a break statement that was needed. Caught by clang's unannotated case fall through warning.
llvm-svn: 263830
2016-03-18 20:53:35 +00:00
Jason Molenda e2a35c728c Bump the lldb version # in the xcode project files from
350.99.0 to 360.99.0.

llvm-svn: 263529
2016-03-15 04:36:11 +00:00
Greg Clayton cec91ef921 Fix all of the unannotated switch cases to annotate the fall through or do the right thing and break.
llvm-svn: 261950
2016-02-26 01:20:20 +00:00
Greg Clayton 6ae1a11d4d Removed unused functions.
llvm-svn: 261768
2016-02-24 20:47:13 +00:00
Pavel Labath 7326c01aaa [linux] Remove all traces of signalfd(2)
Summary:
Signalfd is not used in the code anymore, and given that the same functionality can be achieved
with the new MainLoop class, it's unlikely we will need it in the future. Remove all traces of
it.

Reviewers: tberghammer, ovyalov

Subscribers: tberghammer, danalbert, srhines, lldb-commits

Differential Revision: http://reviews.llvm.org/D17510

llvm-svn: 261631
2016-02-23 12:26:08 +00:00
Jason Molenda 878ae01889 This patch stops lldb from loading a .lldbinit file from the current
working directory by default -- a typical security problem that we
need to be more conservative about.

It adds a new target setting, target.load-cwd-lldbinit which may
be true (always read $cwd/.lldbinit), false (never read $cwd/.lldbinit)
or warn (warn if there is a $cwd/.lldbinit and don't read it).  The
default is set to warn.  If this is met with unhappiness, we can look
at changing the default to true (to match current behavior) on a 
different platform.

This does not affect reading of ~/.lldbinit - that will still be read,
as before.  If you run lldb in your home directory, it will not warn
about the presence of a .lldbinit file there.

I had to add two SB API - SBHostOS::GetUserHomeDirectory and 
SBFileSpec::AppendPathComponent - for the lldb driver code to be
able to get the home directory path in an OS neutral manner.

The warning text is

There is a .lldbinit file in the current directory which is not being read.
To silence this warning without sourcing in the local .lldbinit,
add the following to the lldbinit file in your home directory:
    settings set target.load-cwd-lldbinit false
To allow lldb to source .lldbinit files in the current working directory,
set the value of this variable to true.  Only do so if you understand and
accept the security risk.

<rdar://problem/24199163> 

llvm-svn: 261280
2016-02-19 00:05:17 +00:00
Saleem Abdulrasool 1ee07253c7 Silence some clang warnings
Silences -Wmissing-brace and -Wformat-pedantic warnings from clang on Linux.  NFC.

llvm-svn: 260914
2016-02-15 21:50:28 +00:00
Tamas Berghammer 2e912ec705 Add new option to lldb-server to display its version
llvm-svn: 260366
2016-02-10 10:35:48 +00:00
Jim Ingham 78591726fd Add a missing break.
llvm-svn: 260345
2016-02-10 01:33:58 +00:00
Greg Clayton 0e14c04479 If we set the DYLD_INSERT_LIBRARIES environment variable when launching debugserver, for use with /usr/lib/libgmalloc.dylib, then make sure we don't pass this environment variable on to any child processes.
llvm-svn: 260284
2016-02-09 21:20:17 +00:00
Eugene Leviant ed203da558 Show real error message in -data-evaluate-expression
llvm-svn: 260082
2016-02-08 10:04:51 +00:00
Pavel Labath 6698f6f4e5 Have lldb-server log the timestamp in its log messages
llvm-svn: 260078
2016-02-08 09:35:53 +00:00
Eugene Leviant ec4d04e507 Fix crash in lldb-mi when stack variable name is nullptr. This always happens when execution stops in try scope with unnamed catch clause
llvm-svn: 259189
2016-01-29 12:17:09 +00:00
Pavel Labath 941ca06688 Fix linking of lldb-server with BUILD_SHARED_LIBS
Summary:
The BUILD_SHARED_LIBS branch of lldb-server link flags was hopelessly broken, at least since we
started restricting the symbols exported by liblldb. lldb-server depends on symbols from the
lldb_private namespace, so it cannot link to the public interface of liblldb. Instead I make it
link to the individual libraries constituting liblldb, just like it does in the
!BUILD_SHARED_LIBS case.

This does not make the BUILD_SHARED_LIBS build of lldb fully functional yet, due to the way
liblldb dependencies are managed, but it's a step in that direction.

Reviewers: zturner, tfiala

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D16678

llvm-svn: 259188
2016-01-29 11:59:57 +00:00
Todd Fiala 56d2073319 add back an Xcode-specific Makefile for header installation
llvm-svn: 259102
2016-01-28 22:34:36 +00:00
Eugene Zelenko c33088f41e Remove autoconf support from source directories.
Differential revision: http://reviews.llvm.org/D16662

llvm-svn: 259098
2016-01-28 22:05:24 +00:00
Greg Clayton 17499dde46 A while back in revison 244716 we added support for getting the host OS version info from debugserver. We added keys to "qHostInfo" that were "osmajor", "osminor" and "ospatch", but no one ever parsed those, so I am removing them from debugserver. We accidentally also added a "version" key to qHostInfo instead of "os_version". So now we need to support both "version" and "os_version" in qHostInfo since we have debugserver binaries out in the wild that support this old packet type. I have updated debugserver ot use the correct "os_version" for future compatability or correctness.
<rdar://problem/24378699> 

llvm-svn: 259003
2016-01-28 00:16:11 +00:00
Sean Callanan 10badfc924 Fixed some #ifdefs. We were erroneously not supporting certain simulators.
We had some #ifdefs that were looking for the wrong #defines and as a result
debugserver didn't have support for certain simulators.  This patch resolves
the problem.

llvm-svn: 258365
2016-01-20 23:12:39 +00:00
Jason Molenda 77f8935218 Changes to lldb and debugserver to reduce extraneous memory reads
at each public stop to improve performance a bit.  Most of the 
information lldb needed was already in the jThreadsInfo response;
complete that information and catch a few cases where we could still
fall back to getting the information via discrete memory reads.


debugserver adds 'associated_with_dispatch_queue' and 'dispatch_queue_t
keys to the jThreadsInfo response for all the threads.  lldb needs the
dispatch_queue_t value.  And associated_with_dispatch_queue helps to
identify which threads definitively don't have any queue information so
lldb doesn't try to do memory reads to get that information just because
it was absent in the jThreadsInfo response.

Remove the queue information from the questionmark (T) packet.  We'll
get the information for all threads via the jThreadsInfo response -
sending the information for the stopping thread (on all the private
stops, plus the less frequent public stop) was unnecessary information
being sent over the wire.

SystemRuntimeMacOSX will try to get information about queues by asking
the Threads for them, instead of reading memory.  

ProcessGDBRemote changes to recognize the new keys being sent in the
jThreadsInfo response.  Changes to ThreadGDBRemote to track the new
information.  Also, when a thread is marked as definitively not 
associated with a libdispatch queue, don't fall back to the system
runtime to try memory reads to find the queue name / kind / ID etc.


<rdar://problem/23309359> 

llvm-svn: 257453
2016-01-12 07:09:16 +00:00
Jason Molenda 0c015c6279 In the questionmark packet ("T"), print the "threads:" and "thread-pcs:"
keys before we print the libdispatch queues keys (qname, qkind, qserialnum)
to make it easier to read the packet by hand.  No function difference, just
reordering the keys in the output.

llvm-svn: 257229
2016-01-08 23:16:03 +00:00
Jason Molenda 26d84e8097 Change the key name for the libdispatch queue serial number from
"qserial" to "qserialnum" because "qserial" looks a lot like the
queue type (either 'serial' or 'concurrent') and can be confusing
to read through.  debugserver passes these up either in the questionmark
("T") packet, or in the response to the jThreadsInfo packet.

llvm-svn: 257121
2016-01-08 00:20:48 +00:00
Dawn Perchik 07ac14fa48 Apply missed changes from svn r256863 "Add support for "source info" and use it to fix MI's -symbol-list-lines.".
Patch is part of Differential Revision: http://reviews.llvm.org/D15593
Differential Revision: http://reviews.llvm.org/D15904

llvm-svn: 256877
2016-01-06 00:03:43 +00:00
Dawn Perchik 954b40bf63 Add support for "source info" and use it to fix MI's -symbol-list-lines.
This patch adds support the command 'source info' as follows:
    (lldb) help source info
         Display source line information (as specified) based on the current executable's
         debug info.
    
    Syntax: source info <cmd-options>
    
    Command Options Usage:
      source info [-c <count>] [-s <shlib-name>] [-f <filename>] [-l <linenum>] [-e <linenum>]
      source info [-c <count>] [-s <shlib-name>] [-n <symbol>]
      source info [-c <count>] [-a <address-expression>]
    
           -a <address-expression> ( --address <address-expression> )
                Lookup the address and display the source information for the corresponding
                file and line.
    
           -c <count> ( --count <count> )
                The number of line entries to display.
    
           -e <linenum> ( --end-line <linenum> )
                The line number at which to stop displaying lines.
    
           -f <filename> ( --file <filename> )
                The file from which to display source.
    
           -l <linenum> ( --line <linenum> )
                The line number at which to start the displaying lines.
    
           -n <symbol> ( --name <symbol> )
                The name of a function whose source to display.
    
           -s <shlib-name> ( --shlib <shlib-name> )
                Look up the source in the given module or shared library (can be specified
                more than once).
For example:
    (lldb) source info --file x.h
    Lines for file x.h in compilation unit x.cpp in `x
    [0x0000000100000d00-0x0000000100000d10): /Users/dawn/tmp/./x.h:10
    [0x0000000100000d10-0x0000000100000d1b): /Users/dawn/tmp/./x.h:10

The new options are used to fix the MI command:
    -symbol-list-lines <file>
which didn't work for header files because it called:
    target modules dump line-table <file>
which only dumps line tables for a compilation unit.

The patch also fixes a bug in the error reporting when no files were supplied to the command. Previously you'd get:
    (lldb) target modules dump line-table
    error:
    Syntax:
    error: no source filenames matched any command arguments
Now you get:
    error: file option must be specified.

Reviewed by: clayborg, jingham, ki.stfu
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D15593

llvm-svn: 256863
2016-01-05 19:51:51 +00:00
Ed Maste a6b380652d Wrap Notes in --help output to 80 columns
llvm-svn: 255774
2015-12-16 15:49:38 +00:00
Jason Molenda 7e9bd599a2 Add a new "thread-pcs" key-value pair to the T packet response from
debugserver.  thread-pcs has a comma separated list of base 16
addresses - the current pc value for every thread in the process.
It is a partner of the "threads:" key where a list of thread IDs
is given.  The pc values in thread-pcs correspond one-to-one with
the thread IDs in the threads list.

This is a part of performance work.  When lldb is instruction
stepping / fast stepping over a range of addresses for e.g. a "next"
command, and it steps in to another function, lldb will put a
breakpoint on the return address and continue the process.  Before
it calls continue, it calls Thread::SetupForResume on all the
threads, and SetupForResume needs to get the current pc value for
every thread to see if any are at a breakpoint site.

The result is that issuing a "c" continue requires that we send
"read pc register" packets for every thread.

We may do this sequence of step-into-function / continue-to-get-out
many times for a single user-visible "next" or "step" command, and
with highly multithreaded programs, we are sending many extra
packets to get all the thread values.

I looked at including this data in the "jstopinfo" JSON that
we already have in the T packet.  But there are three problems that
would make this increase the size of the T packet significantly.
First, numbers in JSON are base 10.  Second, a proper JSON would
have something like "thread_pcs": { "34224331112":383772734222, ...}
for thread-id 34224331112 and pc 383772734222 - so we're including
a whole extra copy of the thread id in addition to the pc.  Third,
the JSON text is hex-ascii'fied so the size of it is doubled.
In one example, 

threads:585db8,585dc7,585dc8,585dc9,585dca,585dce;thread-pcs:100001400,7fff8badc6de,7fff8badcff6,7fff8badc6de,7fff8badc6de,7fff8badc6de;

The "thread-pcs" adds 86 characters - 136 characters for both 
threads and thread-pcs.  Doing this in JSON would look like

threads={"5791160":4294972416,"5791175":140735536809694,"5791176":140735536812022,"5791177":140735536809694,"5791178":140735536809694,"5791182":140735536809694}

or 160 characters -- or 320 characters once it is hex-asciified.

Given that it's 86 characters vrs 320, I went with the old style
approach.  I've seen real world programs that have up to 60 threads
in them, so this could result in vastly larger packets if it
was all done in the JSON with hex-ascii expansion.

If we had an all-JSON T packet, where we didn't need to hex-ascii
encode anything, that would have been the better approach.  But
we'd already have a list of threads in JSON at that point so
the additional text wouldn't be too bad.

I'm working on finishing the patches to lldb to use this data;
will commit those once I've had a chance to test them more.  But
I wanted to commit the debugserver bits which are more
straightforward.


<rdar://problem/21963031> 

llvm-svn: 255711
2015-12-15 23:47:44 +00:00
Jason Molenda 0071be6590 When supplying memory to expedite the unwinds in the T packet,
include two stack frames worth of unwind information instead of
just one -- the unwinder is trying to fetch two stack frames in
more instances now and we're sending extra memory reads resulting
in a performance degredation while stepping.

llvm-svn: 255417
2015-12-12 01:32:09 +00:00