Commit Graph

2419 Commits

Author SHA1 Message Date
Jonas Devlieghere
971f9ca612 Let tablegen generate property definitions
Property definitions are currently defined in a PropertyDefinition array
and have a corresponding enum to index in this array. Unfortunately this
is quite error prone. Indeed, just today we found an incorrect merge
where a discrepancy between the order of the enum values and their
definition caused the test suite to fail spectacularly.

Tablegen can streamline the process of generating the property
definition table while at the same time guaranteeing that the enums stay
in sync. That's exactly what this patch does. It adds a new tablegen
file for the properties, building on top of the infrastructure that
Raphael added recently for the command options. It also introduces two
new tablegen backends: one for the property definitions and one for
their corresponding enums.

It might be worth mentioning that I generated most of the tablegen
definitions from the existing property definitions, by adding a dump
method to the struct. This seems both more efficient and less error
prone that copying everything over by hand. Only Enum properties needed
manual fixup for the EnumValues and DefaultEnumValue fields.

Differential revision: https://reviews.llvm.org/D65185

llvm-svn: 367058
2019-07-25 21:36:37 +00:00
Michal Gorny
e1c159e86a [lldb] [Process/NetBSD] Report stopped process on SIGSTOP
Mark the process as stopped when SIGSTOP arrives.  This is necessary
for lldb-server to generate correct response to 'process interrupt',
and therefore to prevent the whole stack crashing when process
is stopped.

Thanks to Pavel Labath for the tip.

Differential Revision: https://reviews.llvm.org/D65289

llvm-svn: 367047
2019-07-25 20:27:40 +00:00
Antonio Afonso
d668260f1a Correctly use GetLoadedModuleList to take advantage of libraries-svr4
Summary:
Here's a replacement for D62504. I thought I could use LoadModules to implement this but in reality I can't because there are at few issues with it:
* The LoadModules assumes that the list returned by GetLoadedModuleList is comprehensive in the sense that reflects all the mapped segments, however, this is not true, for instance VDSO entry is not there since it's loaded manually by LoadVDSO using GetMemoryRegionInfo and it doesn't represent a specific shared object in disk. Because of this LoadModules will unload the VDSO module.
* The loader (interpreter) module might have also been loaded using GetMemoryRegionInfo, this is true when we launch the process and the rendezvous structure is not yet available (done through LoadInterpreterModule()). The problem here is that this entry will point to the same file name as the one found in /proc/pid/maps, however, when we read the same module from the r_debug.link_map structure it might be under a different name. This is true at least on CentOS where the loader is a symlink. Because of this LoadModules will unload and load the module in a way where the rendezvous breakpoint is unresolved but not resolved again (because we add the new module first and remove the old one after).

The symlink issue might be fixable by first unloading the old and loading the news (but sounds super brittle), however, I'm not sure how to fix the VDSO issue.
Since I can't trust it I'm just going to use GetLoadedModuleList directly with the same logic that we use today for when we read the linked list in lldb. The only safe thing to do here is to only calculate differences between different snapshots of the svr4 packet itself. This will also cut the dependency this plugin has from LoadModules.

I separated the 2 logics into 2 different functions (remote and not remote) because I don't like mixing 2 different logics in the same function with if/else's. Two different functions makes it easier to reason with I believe. However, I did abstract away the logic that decides if we should take a snapshot or add/remove modules so both functions could reuse it.

The other difference between the two is that on the UpdateSOEntriesFromRemote I take the snapshot only once when state = Consistent because I didn't find a good reason to always update that, as we already got the list from state = Add | Remove. I probably should use the same logic on UpdateSOEntries though I don't see a reason not to since it's really using the same data, just read in different places. Any thoughts here?

It might also be worthwhile to add a test to make sure we don't unload modules that were not actually "unloaded" like the vdso. I haven't done this yet though.
This diff is also missing the option for svr4 like proposed in https://reviews.llvm.org/D62503#1564296, I'll start working on this but wanted to have this up first.

Reviewers: labath, jankratochvil, clayborg, xiaobai

Reviewed By: labath

Subscribers: srhines, JDevlieghere, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D64013

llvm-svn: 367020
2019-07-25 14:28:21 +00:00
Pavel Labath
ee74c9e5fd LLGS: fix tracking execve on linux
Summary:
Due to a logic error, lldb-server ended up asserting/crashing every time
the debugged process attempted an execve(). This fixes the error, and
extends TestExec to work on other platforms too. The "extension"
consists of avoiding non-standard posix_spawn extensions and using the
classic execve() call, which should be available on any platform that
actually supports re-execing. I change the test decorator from
@skipUnlessDarwin to @skipIfWindows.

Reviewers: clayborg, jasonmolenda

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D65207

llvm-svn: 366985
2019-07-25 06:38:33 +00:00
Jonas Devlieghere
63e5fb76ec [Logging] Replace Log::Printf with LLDB_LOG macro (NFC)
This patch replaces explicit calls to log::Printf with the new LLDB_LOGF
macro. The macro is similar to LLDB_LOG but supports printf-style format
strings, instead of formatv-style format strings.

So instead of writing:

  if (log)
    log->Printf("%s\n", str);

You'd write:

  LLDB_LOG(log, "%s\n", str);

This change was done mechanically with the command below. I replaced the
spurious if-checks with vim, since I know how to do multi-line
replacements with it.

  find . -type f -name '*.cpp' -exec \
  sed -i '' -E 's/log->Printf\(/LLDB_LOGF\(log, /g' "{}" +

Differential revision: https://reviews.llvm.org/D65128

llvm-svn: 366936
2019-07-24 17:56:10 +00:00
Michal Gorny
b09bc8a27d Revert "Revert "[lldb] [Process/NetBSD] Fix constructor after r363707""
The relevant changes have been reapplied, and broke build again.

llvm-svn: 366889
2019-07-24 11:44:43 +00:00
Antonio Afonso
70795c1e3a Revert "Revert "Add ReadCStringFromMemory for faster string reads""
This reverts commit 9c10b620c0.

llvm-svn: 366848
2019-07-23 20:40:37 +00:00
Antonio Afonso
05e32bad13 Revert "Revert "Implement xfer:libraries-svr4:read packet""
This reverts commit 08c38f77c5.

llvm-svn: 366847
2019-07-23 20:40:30 +00:00
Pavel Labath
c4c25e11b1 ProcessMachCore: Fix a -Wmisleading-indentation warning
llvm-svn: 366803
2019-07-23 12:53:45 +00:00
Jonas Devlieghere
b2a9cf7764 [Logging] Replace LogIfAnyCategoriesSet with LLDB_LOG.
This patch removes any remaining instances of LogIfAnyCategoriesSet and
replaces them with the LLDB_LOG macro. This in turn made it possible to
make Log::VAPrintf and Log::VAError private.

llvm-svn: 366768
2019-07-22 23:48:01 +00:00
Adrian McCarthy
3f06210295 [Windows] Fix race condition between state changes
Patch by Martin Andersson (martin.andersson@evoma.se)

If the process is resumed before the state is changed to "running"
there is a possibility (when single stepping) that the debugger stops
and changes the state to "stopped" before it is first changed to
"running". This causes the process to ignore the stop event (since
the state did not change) which in turn leads the DebuggerThread to
wait indefinitely for the exception predicate in HandleExceptionEvent.

Differential Revision: https://reviews.llvm.org/D62183

llvm-svn: 366703
2019-07-22 17:03:20 +00:00
Joseph Tremoulet
3fd917d886 Support Linux signal return trampolines in frame initialization
Summary:
Add __kernel_rt_sigreturn to the list of trap handlers for Linux (it's
used as such on aarch64 at least), and __restore_rt as well (used on
x86_64).

Skip decrement-and-recompute for trap handlers in
InitializeNonZerothFrame, as signal dispatch may point the child frame's
return address to the start of the return trampoline.

Parse the 'S' flag for signal handlers from eh_frame augmentation, and
propagate it to the unwind plan.

Reviewers: labath, jankratochvil, compnerd, jfb, jasonmolenda

Reviewed By: jasonmolenda

Subscribers: clayborg, MaskRay, wuzish, nemanjai, kbarton, jrtc27, atanasyan, jsji, javed.absar, kristof.beyls, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D63667

llvm-svn: 366580
2019-07-19 14:05:55 +00:00
Jason Molenda
be4be6120f Add support to ProcessMachCore::DoLoadCore to handle an EFI UUID str.
If a core file has an EFI version string which includes a UUID
(similar to what it returns for the kdp KDP_KERNELVERSION packet)
in the LC_IDENT or LC_NOTE 'kern ver str' load command.  In that
case, we should try to find the binary and dSYM for the UUID
listed.  The dSYM may have python code which knows how to relocate
the binary to the correct address in lldb's target section load
list and loads other ancillary binaries.

The test case is a little involved,

1. it compiles an inferior hello world apple (a.out),
2. it compiles a program which can create a corefile manually
   with a specific binary's UUID encoded in it,
3. it gets the UUID of the a.out binary,
4. it creates a shell script, dsym-for-uuid.sh, which will
   return the full path to the a.out + a.out.dSYM when called
   with teh correct UUID,
5. it sets the LLDB_APPLE_DSYMFORUUID_EXECUTABLE env var before
   creating the lldb target, to point to this dsym-for-uuid.sh,
6. runs the create-corefile binary we compiled in step #2,
7. loads the corefile from step #6 into lldb,
8. verifies that lldb loaded a.out by reading the LC_NOTE
   load command from the corefile, calling dsym-for-uuid.sh with
   that UUID, got back the path to a.out and loaded it.

whew!

<rdar://problem/47562911>

llvm-svn: 366378
2019-07-17 21:44:05 +00:00
David Carlier
65d49fa60f [LLDB] Fix FreeBSD build.
To align with the LaunchThread change.

Reviewers: MaskRay, mgorny

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D64398

llvm-svn: 365761
2019-07-11 12:21:04 +00:00
Aaron Smith
053eb35651 Try again to move common functionality from ProcessWindows into ProcessDebugger
This reverts commit ed499a36b6 and addresses
a problem causing a Windows build bot to hang.

llvm-svn: 365592
2019-07-10 03:34:57 +00:00
Stella Stamenova
631b5f7dc0 [lldb, windows] Update two more locations that use LaunchThread to the new function signature
llvm-svn: 365526
2019-07-09 18:10:36 +00:00
Stella Stamenova
ed499a36b6 Revert "Move common functionality from processwindows into processdebugger"
This reverts commit 9c01eaff6a.

The changes in this commit are causing several of the LLDB tests to hang and/or timeout.

llvm-svn: 365371
2019-07-08 18:53:32 +00:00
Saleem Abdulrasool
842f55f3ef Process: generalise Windows thread setup
The Windows build currently cannot support debugging foreign targets or
debugging Windows ARM NT and Windows ARM64 targets.  Do not assume a
x64/x86 host.  This enables building lldb for Windows ARM64.

llvm-svn: 365282
2019-07-07 17:58:11 +00:00
Jonas Devlieghere
f39c2e188d Change LaunchThread interface to return an expected.
Change the interface to return an expected, instead of taking a Status
pointer.

Differential revision: https://reviews.llvm.org/D64163

llvm-svn: 365226
2019-07-05 17:42:08 +00:00
Saleem Abdulrasool
1522073fed Plugins: permit building on Windows ARM64
Rather than relying on `sizeof(void *)` to determine the architecture,
use the `CMAKE_SYSTEM_PROCESSOR` variable.  This should allow us to
build for Windows and cross-compile.  Without this, we would attempt to
build the x64 plugin on ARM64 which would fail due to the `CONTEXT` type
being defined for ARM64 rather than `x64`.

llvm-svn: 365155
2019-07-04 19:26:49 +00:00
Antonio Afonso
f8251f1ee6 Add plugin.process.gdb-remote.use-libraries-svr4 option
Summary:
This option allow the toggling of the libraries-svr4 usage in ProcessGDBRemote. It's a follow up of https://reviews.llvm.org/D62503#1564296 and it's meant to test / tweak this new packet with, hopefully, minimum impact and in a faster way.

Enable it with `settings set plugin.process.gdb-remote.use-libraries-svr4 true`. For now, by default it's false.

I didn't put tests up for this but I did test it manually.

Reviewers: labath, jankratochvil

Reviewed By: labath

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D64112

llvm-svn: 365059
2019-07-03 17:30:07 +00:00
Jonas Devlieghere
730bed5c83 [Reproducer] Assert on unexpected packet
I'm not able to reproduce the reproducer flakiness we're seeing on
GreenDragon. I want to add this assert to find out if the GDB remote
packets are somehow getting out of sync when this happens.

llvm-svn: 364852
2019-07-01 21:25:34 +00:00
Michal Gorny
0856721e3a [lldb] [Process/NetBSD] Use global enable bits for watchpoints
Set global enable bits (i.e. bits 1, 3, 5, 7) to enable watchpoints
on NetBSD rather than the local enable bits (0, 2, 4, 6).  The former
are necessary for watchpoints to be correctly recognized by the NetBSD
kernel.  The latter cause them to be reported as trace points.

Differential Revision: https://reviews.llvm.org/D63792

llvm-svn: 364781
2019-07-01 15:11:42 +00:00
Michal Gorny
baf64b6505 [lldb] [Process/NetBSD] Fix segfault when handling watchpoint
Fix the watchpoint/breakpoint code to search for matching thread entry
in m_threads explicitly rather than assuming that it will be present
at specified index.  The previous code segfault since it wrongly assumed
that the index will match LWP ID which was incorrect even for a single
thread (where index was 0 and LWP ID was 1).

While fixing that off-by-one error would help for this specific task,
I believe it is better to be explicit in what we are searching for.

Differential Revision: https://reviews.llvm.org/D63791

llvm-svn: 364780
2019-07-01 15:11:10 +00:00
Michal Gorny
2b2ad9342e [lldb] [Process/NetBSD] Support reading YMM registers via PT_*XSTATE
Provide a (conditional) support for the new PT_GETXSTATE
and PT_SETXSTATE ptrace() requests, and use them to implement getting
and setting YMM registers.  The functions used for splitting
and recombining YMM register data are based on matching functions
in FreeBSD plugin, with some simplification and updates to match NetBSD
structures.

Differential Revision: https://reviews.llvm.org/D63545

llvm-svn: 364779
2019-07-01 15:11:04 +00:00
Michal Gorny
535f39ce52 Revert "[lldb] [Process/NetBSD] Fix constructor after r363707"
Now that r364751 has been reverted, we need to revert this fixup
as well.

llvm-svn: 364776
2019-07-01 14:38:47 +00:00
Pavel Labath
c12dfcf1f5 Don't check the validity of newly contructed data buffers
A bunch of places were checking that DataBufferHeap::GetBytes returns a
non-null pointer right after constructing it. The only time when
GetBytes returns a null pointer is if it is empty (and I'm not sure that
even this is a good idea), but that is clearly not the case here, as the
buffer was constructed with a non-zero size just a couple of lines back.

llvm-svn: 364754
2019-07-01 13:18:19 +00:00
Pavel Labath
08c38f77c5 Revert "Implement xfer:libraries-svr4:read packet"
D62502, together with D62503 have broken the builds which have XML
support enabled. Reverting D62503 (r364355) fixed that, but has broken
has left some of the tests introduced by D62502 broken more or less
nondeternimistically (it depended on whether the system happens to place
the library list near unreadable pages of memory). I attempted to make a
partial fix for this in r364748, but Jan Kratochvil pointed out that
this reintroduces the problem which reverting D62503 was trying to
solve.

So instead, I back out the whole thing so we can get back to a clean
slate that works for everyone. We can figure out a way forward from
there.

This reverts r364748, r363772 and r363707.

llvm-svn: 364751
2019-07-01 12:41:20 +00:00
Pavel Labath
4f0a377280 Fix TestGdbRemoteLibrariesSvr4Support
D62502 had a bug (visible only with D62503 reverted), where it would
error out if attempting to read a string from memory and the memory page
after the string happened to be unmapped.

This fixes the problem by checking for whether ReadMemory read *any*
bytes, instead of checking whether it returned an error. A greater
question is whether ReadMemory should even return an error if it read at
least one byte, but I'm leaving that for a separate patch.

llvm-svn: 364748
2019-07-01 12:00:25 +00:00
Pavel Labath
0f73709cb7 Remove null checks of results of new expressions
operator new doesn't return a null pointer, even if one turns off
exceptions (it calls std::terminate instead). Therefore, all of this is
dead code.

llvm-svn: 364744
2019-07-01 11:09:15 +00:00
Jonas Devlieghere
135cf982e8 Revert "[GDBRemote] Remove code that flushes GDB remote packets"
Reverting this again as it doesn't appear to solve the flakiness on the
LLDB standalone bot.

llvm-svn: 364722
2019-06-30 19:00:09 +00:00
Jonas Devlieghere
9db6073381 [GDBRemote] Remove code that flushes GDB remote packets
The arbitrary timeout when flushing GDB remote packets caused
non-determinism and flakiness between test runs. I suspect it is what's
causing the flakiness of the reproducer tests on GreenDragon, and want
to see if removing it causes that to go away.

This change was originally introduced in r197579 to discard a
`$T02thread:01;#4` that QEMU was sending. If anybody knows how to test
that this continues working after removing this code, I'd love to hear
it.

llvm-svn: 364669
2019-06-28 18:14:27 +00:00
Jim Ingham
8864b4360a Make sure the thread list is updated before you set the stop reason
on a thread.  When talking to some older gdb-remote stubs, We were getting
a stop reason from the stop reply packet and setting it on the relevant
thread before we updated the full stop list.  That would get discarded when
the full list was updated.

Also, if you already have a thread list when you go to see if there is an
Operating System plugin, and you do indeed load a new OS plugin, you have to
re-fetch the thread list or it will only show the raw threads.

Differential Revision: https://reviews.llvm.org/D62887

llvm-svn: 364666
2019-06-28 17:57:19 +00:00
Jonas Devlieghere
d661a06bed [Reproducers] Fix flakiness and off-by-one during replay.
This fixes two replay issues that caused the tests to behave
erratically:

1. It fixes an off-by-one error, where all replies where shifted by 1
   because of a `+` packet that should've been ignored.

2. It fixes another off-by-one-error, where an asynchronous ^C was
   offsetting all subsequent packets. The reason is that we
   'synchronize' requests and replies. In reality, a stop reply is only
   sent when the process halt. During replay however, we instantly
   report the stop, as the reply to packets like continue (vCont).

Both packets should be ignored, and indeed, checking the gdb-remote log,
no unexpected packets are received anymore.

Additionally, be more pedantic when it comes to unexpected packets and
return an failure form the replay server. This way we should be able to
catch these things faster in the future.

llvm-svn: 364494
2019-06-27 02:03:34 +00:00
Jason Molenda
1659276bee Support nested target.xml register definition files, lack of reg group markers.
The qemu x86_64 target returns a target.xml register definition file which
includes other xml files and they include others, etc.  Also, the registers
are not put in register groups like lldb wants to see.

This patch (1) puts registers that aren't in a register group in a "general"
register group, (2) change ProcessGDBRemote::GetGDBServerRegisterInfo to
be a method that starts the parsing, asking a recurisve function to fetch
and parse target.xml, (3) adds 
ProcessGDBRemote::GetGDBServerRegisterInfoXMLAndProcess which can recusively
call itself to read and parse included xml files, (4) in addition to expecting
the top-level <target> element (which only happens in the top level xml file),
also an xml file that consists of a <feature> node - read the register 
defintions and includes from that <feature> element.  

<rdar://problem/49537922> 
Differential revision: https://reviews.llvm.org/D63802

llvm-svn: 364484
2019-06-26 21:59:39 +00:00
Antonio Afonso
9c10b620c0 Revert "Add ReadCStringFromMemory for faster string reads"
This reverts commit a7335393f5.

It seems this is breaking a bunch of tests (https://reviews.llvm.org/D62503#1549874) so reverting until I find the time to repro and fix.

llvm-svn: 364355
2019-06-25 22:22:13 +00:00
Alex Langford
09ede9d65f [ABI] Implement Windows ABI for x86_64
Summary:
Implement the ABI for WIndows-x86_64 including register info and calling convention.
Handled nested struct returned in register (SysV doesn't have it supported)

Reviewers: xiaobai, compnerd

Reviewed By: compnerd

Subscribers: labath, jasonmolenda, fedor.sergeev, mgorny, teemperor, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D62213

llvm-svn: 364216
2019-06-24 18:21:05 +00:00
Aaron Smith
9c01eaff6a Move common functionality from processwindows into processdebugger
Summary:
This change extracts functionalities from processwindows into a
introduced processdebugger that can be reused in native process
debugging. 

The main reason is that the native process debugging
can't directly be based on processwindows or be implemented
as a pass-through to this plugin since the plugin has ties to
Target and Process classes that are needed in host debugging but
not necessary in native debugging.

Reviewers: labath, Hui, jfb, clayborg, amccarth

Reviewed By: labath

Subscribers: amccarth, dexonsmith, mgorny, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D63166

llvm-svn: 364210
2019-06-24 17:43:47 +00:00
Michal Gorny
8805829289 [lldb] [Process] Introduce common helpers to split/recombine YMM data
Introduce two common helpers to take care of splitting and recombining
YMM registers to/from XSAVE-like data.  Since FreeBSD, Linux and NetBSD
all use XSAVE-like data structures but with potentially different field
layouts, the function takes two pointers -- to XMM register and to YMM
high bits, and copies the data from/to YMMReg type.

While at it, remove support for big endian.  To mine and Pavel Labath's
combined knowledge, there is no such thing on x86.  Furthermore,
assuming that the YMM register data would be swapped for big endian
seems to be a weird assumption.

Differential Revision: https://reviews.llvm.org/D63610

llvm-svn: 364042
2019-06-21 13:19:34 +00:00
Michal Gorny
d687fa7d02 [lldb] [Process/NetBSD] Remove unnecessary register buffer abstraction
Remove most of the abstraction over ptrace() register operations,
as it has little value and introduces more code than it saves.
Instead, leave a single ptrace() wrapper method and call it directly
from ReadRegisterSet() and WriteRegisterSet() with correct PT_* request
and buffer.

Remove the remaining direct ReadGPR() and WriteGPR() invocations
with ReadRegisterSet() and WriteRegisterSet().

Cleanup suggested by Pavel Labath in D63545.

Differential Revision: https://reviews.llvm.org/D63594

llvm-svn: 363923
2019-06-20 12:44:37 +00:00
Alex Langford
86df61cc93 [Process] Remove unused field from HistoryThread
Summary:
These fields are unused and have been since their inception, from what
I can tell.

Reviewers: compnerd, JDevlieghere, davide, labath

Subscribers: kubamracek, lldb-commits

Differential Revision: https://reviews.llvm.org/D63357

llvm-svn: 363881
2019-06-19 21:33:44 +00:00
Michal Gorny
a5992997d9 [lldb] [Process/NetBSD] Fix constructor after r363707
llvm-svn: 363827
2019-06-19 15:49:47 +00:00
Michal Gorny
a644b04b8c [lldb] [Process/NetBSD] Remove unnecessary FPU presence checks for x86_64
Remove the checks for FPU presence, FXSAVE support and usage from
the code for x86_64.  Those are always true for this architecture,
and in fact are hardcoded to true inside NetBSD kernel.

Differential Revision: https://reviews.llvm.org/D63554

llvm-svn: 363823
2019-06-19 15:35:01 +00:00
Antonio Afonso
a7335393f5 Add ReadCStringFromMemory for faster string reads
Summary:
This is the fifth patch to improve module loading in a series that started here (where I explain the motivation and solution): D62499

Reading strings with ReadMemory is really slow when reading the path of the shared library. This is because we don't know the length of the path so use PATH_MAX (4096) and these strings are actually super close to the boundary of an unreadable page. So even though we use process_vm_readv it will usually fail because the read size spans to the unreadable page and we then default to read the string word by word with ptrace.

This new function is very similar to another ReadCStringFromMemory that already exists in lldb that makes sure it never reads cross page boundaries and checks if we already read the entire string by finding '\0'.

I was able to reduce the GetLoadedSharedLibraries call from 30ms to 4ms (or something of that order).

Reviewers: clayborg, xiaobai, labath

Reviewed By: labath

Subscribers: emaste, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D62503

llvm-svn: 363750
2019-06-18 23:27:57 +00:00
Antonio Afonso
fda83c9b0b Implement xfer:libraries-svr4:read packet
Summary:
This is the fourth patch to improve module loading in a series that started here (where I explain the motivation and solution): D62499

Implement the `xfer:libraries-svr4` packet by adding a new function that generates the list and then in Handle_xfer I generate the XML for it. The XML is really simple so I'm just using string concatenation because I believe it's more readable than having to deal with a DOM api.

Reviewers: clayborg, xiaobai, labath

Reviewed By: labath

Subscribers: emaste, mgorny, srhines, krytarowski, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D62502

llvm-svn: 363707
2019-06-18 17:51:56 +00:00
Antonio Afonso
f4335b8e3c Implement GetSharedLibraryInfoAddress
Summary:
This is the third patch to improve module loading in a series that started here (where I explain the motivation and solution): D62499

Add functions to read the r_debug location to know where the linked list of loaded libraries are so I can generate the `xfer:libraries-svr4` packet.
I'm also using this function to implement `GetSharedLibraryInfoAddress` that was "not implemented" for linux.
Most of this code was inspired by the current ds2 implementation here: https://github.com/facebook/ds2/blob/master/Sources/Target/POSIX/ELFProcess.cpp.

Reviewers: clayborg, xiaobai, labath

Reviewed By: clayborg, labath

Subscribers: emaste, krytarowski, mgorny, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D62501

llvm-svn: 363458
2019-06-14 21:15:08 +00:00
Jonas Devlieghere
ef96e985fc [Reproducers] Simplify providers with nested Info struct (NFC)
This replaces the `info` typedef with a nested struct named Info. This
means we now have FooProvider and FooProvider::Info, instead of two
related but separate classes FooProvider and FooInfo. This change is
mostly cosmetic.

llvm-svn: 363211
2019-06-12 22:17:38 +00:00
David Carlier
f243ca4af8 [LLDB] Fix FreeBSD build
The auxiliary vector method had the wrong signature.

Reviewers: MaskRay, teemperor, aadsm

Reviewed By: MaskRay, teemperor

Differential Revision: https://reviews.llvm.org/D63187

llvm-svn: 363135
2019-06-12 08:54:14 +00:00
Antonio Afonso
943faef1fa Add support to read aux vector values
Summary:
This is the second patch to improve module loading in a series that started here (where I explain the motivation and solution): https://reviews.llvm.org/D62499

I need to read the aux vector to know where the r_debug map with the loaded libraries are.
The AuxVector class was made generic so it could be reused between the POSIX-DYLD plugin and NativeProcess*. The class itself ended up in the ProcessUtility plugin.

Reviewers: clayborg, xiaobai, labath, JDevlieghere

Reviewed By: clayborg, labath, JDevlieghere

Subscribers: emaste, JDevlieghere, mgorny, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D62500

llvm-svn: 363098
2019-06-11 20:16:13 +00:00
Antonio Afonso
57e2da4f32 Create a generic handler for Xfer packets
Summary:
This is the first of a few patches I have to improve the performance of dynamic module loading on Android.

In this first diff I'll describe the context of my main motivation and will then link to it in the other diffs to avoid repeating myself.

## Motivation
I have a few scenarios where opening a specific feature on an Android app takes around 40s when lldb is attached to it. The reason for that is because 40 modules are dynamicly loaded at that point in time and each one of them is taking ~1s.

## The problem
To learn about new modules we have a breakpoint on a linker function that is called twice whenever a module is loaded. One time just before it's loaded (so lldb can check which modules are loaded) and another right after it's loaded (so lldb can check again which ones are loaded and calculate the diference).
It's figuring out which modules are loaded that is taking quite some time. This is currently done by traversing the linked list of loaded shared libraries that the linker maintains in memory. Each item in the linked list requires its own `x` packet sent to the gdb server (this is android so the network also plays a part). In my scenario there are 400+ loaded libraries and even though we read 0x800 worth of bytes at a time we still make ~180 requests that end up taking 150-200ms.
We also do this twice, once before the module is loaded (state = eAdd) and another right after (state = eConsistent) which easly adds up to ~400ms per module.

## A solution

**Implement `xfer:libraries-svr4` in lldb-server:**
I noticed in the code that loads the new modules that it had support for the `xfer:libraries-svr4` packet (added ~4 years ago to support the ds2 debug server) but we didn't support it in lldb-server. This single packet returns an xml list of all the loaded modules by the process. The advantage is that there's no more need to make 180 requests to read the linked list. Additionally this new requests takes around 10ms.

**More efficient usage of the `xfer:libraries-svr4` packet in lldb:**
When `xfer:libraries-svr4` is available the Process class has a `LoadModules` function that requests this packet and then loads or unloads modules based on the current list of loaded modules by the process.
This is the function that is used by the DYLDRendezvous class to get the list of loaded modules before and after the module is loaded. However, this is really not needed since the LoadModules function already loaded or unloaded the modules accordingly. I changed this strategy to call LoadModules only once (after the process has loaded the module).

**Bugs**
I found a few issues in lldb while implementing this and have submitted independent patches for them.

I tried to devide this into multiple logical patches to make it easier to review and discuss.

## Tests

I wanted to put these set of diffs up before having all the tests up and running to start having them reviewed from a techical point of view. I'm also having some trouble making the tests running on linux so I need more time to make that happen.

# This diff

The `xfer` packages follow the same protocol, they are requested with `xfer:<object>:<read|write>:<annex>:<offset,length>` and a return that starts with `l` or `m` depending if the offset and length covers the entire data or not. Before implementing the `xfer:libraries-svr4` I refactored the `xfer:auxv` to generically handle xfer packets so we can easly add new ones.

The overall structure of the function ends up being:
* Parse the packet into its components: object, offset etc.
* Depending on the object do its own logic to generate the data.
* Return the data based on its size, the requested offset and length.

Reviewers: clayborg, xiaobai, labath

Reviewed By: labath

Subscribers: mgorny, krytarowski, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D62499

llvm-svn: 362982
2019-06-10 20:59:58 +00:00