SimpleRemoteEPC notionally allowed subclasses to override the
createMemoryManager and createMemoryAccess methods to use custom objects, but
could not actually be subclassed in practice (The construction process in
SimpleRemoteEPC::Create could not be re-used).
Instead of subclassing, this commit adds a SimpleRemoteEPC::Setup class that
can be used by clients to set up the memory manager and memory access members.
A default-constructed Setup object results in no change from previous behavior
(EPCGeneric* memory manager and memory access objects used by default).
f341161689 added a task dispatcher for async handlers, but didn't add a
TaskDispatcher::shutdown call to SelfExecutorProcessControl or SimpleRemoteEPC.
This patch adds the missing call, which ensures that we don't destroy the
dispatcher while tasks are still running.
This should fix the use-after-free crash seen in
https://lab.llvm.org/buildbot/#/builders/5/builds/13063
In SimpleRemoteEPC, calls to from callWrapperAsync to sendMessage may fail.
The handlers may or may not be sent failure messages by handleDisconnect,
depending on when that method is run. This patch adds a check for an un-failed
handler, and if it finds one sends it a failure message.
On the controller-side, handle `Hangup` messages from the executor. The executor passed `Error::success()` or a failure message as payload.
Hangups cause an immediate disconnect of the transport layer. The disconnect function may be called later again and so implementations should be prepared. `FDSimpleRemoteEPCTransport::disconnect()` already has a flag to check that:
cd1bd95d87/llvm/lib/ExecutionEngine/Orc/Shared/SimpleRemoteEPCUtils.cpp (L112)
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D111527
The callWrapperAsync and callSPSWrapperAsync methods take a handler object
that is run on the return value of the call when it is ready. The new RunPolicy
parameters allow clients to control how these handlers are run. If no policy is
specified then the handler will be packaged as a GenericNamedTask and dispatched
using the ExecutorProcessControl's TaskDispatch member. Callers can use the
ExecutorProcessControl::RunInPlace policy to cause the handler to be run
directly instead, which may be preferrable for simple handlers, or they can
write their own policy object (e.g. to dispatch as some other kind of Task,
rather than GenericNamedTask).
The callee address is now the first parameter and the 'SendResult' function
the second. This change improves consistentency with the non-async functions
where the callee is the first address and the return value the second.
Adds a 'start' method to SimpleRemoteEPCTransport to defer transport startup
until the client has been configured. This avoids races on client members if the
first messages arrives while the client is being configured.
Also fixes races on the file descriptors in FDSimpleRemoteEPCTransport.
Disconnect should block until handleDisconnect completes, otherwise we might
destroy the SimpleRemoteEPC instance while it's still in use.
Thanks to Dave Blaikie for helping me track this down.
Removing the 'ess' suffix improves the ergonomics without sacrificing clarity.
Since this class is likely to be used more frequently in the future it's worth
some short term pain to fix this now.
EPCGenericDylibManager provides an interface for loading dylibs and looking up
symbols in the executor, implemented using EPC-calls to functions in the
executor.
SimpleExecutorDylibManager is an executor-side service that provides the
functions used by EPCGenericDylibManager.
SimpleRemoteEPC is updated to use an EPCGenericDylibManager instance to
implement the ExecutorProcessControl loadDylib and lookup methods. In a future
commit these methods will be removed, and clients updated to use
EPCGenericDylibManagers directly.
Finalization and deallocation actions are a key part of the upcoming
JITLinkMemoryManager redesign: They generalize the existing finalization and
deallocate concepts (basically "copy-and-mprotect", and "munmap") to include
support for arbitrary registration and deregistration of parts of JIT linked
code. This allows us to register and deregister eh-frames, TLV sections,
language metadata, etc. using regular memory management calls with no additional
IPC/RPC overhead, which should both improve JIT performance and simplify
interactions between ORC and the ORC runtime.
The SimpleExecutorMemoryManager class provides executor-side support for memory
management operations, including finalization and deallocation actions.
This support is being added in advance of the rest of the memory manager
redesign as it will simplify the introduction of an EPC based
RuntimeDyld::MemoryManager (since eh-frame registration/deregistration will be
expressible as actions). The new RuntimeDyld::MemoryManager will in turn allow
us to remove older remote allocators that are blocking the rest of the memory
manager changes.
This is a small first step towards reorganization of the ORC libraries:
Declarations for types and function names (as strings) to be found in the
"ORC runtime bootstrap" set are moved into OrcRTBridge.h / OrcRTBridge.cpp.
The current implementation of the "ORC runtime bootstrap" functions is moved
into OrcRTBootstrap.h and OrcRTBootstrap.cpp. It is likely that this code will
eventually be moved into ORT-RT proper (in compiler RT).
The immediate goal of this change is to make these bootstrap functions usable
for clients other than SimpleRemoteEPC/SimpleRemoteEPCServer. The first planned
client is a new RuntimeDyld::MemoryManager that will run over EPC, which will
allow us to remove the old OrcRemoteTarget code.
Bootstrap symbols are symbols whose addresses may be required to bootstrap
the rest of the JIT. The bootstrap symbols map generalizes the existing
JITDispatchInfo class provide an arbitrary map of symbol names to addresses.
The JITDispatchInfo class will be replaced by bootstrap symbols with reserved
names in upcoming commits.
This reapplies bb27e45643 (SimpleRemoteEPC
support) and 2269a941a4 (#include <mutex>
fix) with further fixes to support building with LLVM_ENABLE_THREADS=Off.
This reverts commit 5629afea91 ("[ORC] Add missing
include."), and bb27e45643 ("[ORC] Add
SimpleRemoteEPC: ExecutorProcessControl over SPS + abstract transport.").
The SimpleRemoteEPC patch currently assumes availability of threads, and needs
to be rewritten with LLVM_ENABLE_THREADS guards.
SimpleRemoteEPC is an ExecutorProcessControl implementation (with corresponding
new server class) that uses ORC SimplePackedSerialization (SPS) to serialize and
deserialize EPC-messages to/from byte-buffers. The byte-buffers are sent and
received via a new SimpleRemoteEPCTransport interface that can be implemented to
run SimpleRemoteEPC over whatever underlying transport system (IPC, RPC, network
sockets, etc.) best suits your use case.
The SimpleRemoteEPCServer class provides executor-side support. It uses a
customizable SimpleRemoteEPCServer::Dispatcher object to dispatch wrapper
function calls to prevent the RPC thread from being blocked (a problem in some
earlier remote-JIT server implementations). Almost all functionality (beyond the
bare basics needed to bootstrap) is implemented as wrapper functions to keep the
implementation simple and uniform.
Compared to previous remote JIT utilities (OrcRemoteTarget*,
OrcRPCExecutorProcessControl), more consideration has been given to
disconnection and error handling behavior: Graceful disconnection is now always
initiated by the ORC side of the connection, and failure at either end (or in
the transport) will result in Errors being delivered to both ends to enable
controlled tear-down of the JIT and Executor (in the Executor's case this means
"as controlled as the JIT'd code allows").
The introduction of SimpleRemoteEPC will allow us to remove other remote-JIT
support from ORC (including the legacy OrcRemoteTarget* code used by lli, and
the OrcRPCExecutorProcessControl and OrcRPCEPCServer classes), and then remove
ORC RPC itself.
The llvm-jitlink and llvm-jitlink-executor tools have been updated to use
SimpleRemoteEPC over file descriptors. Future commits will move lli and other
tools and example code to this system, and remove ORC RPC.
Lang Hames