This patch moves definition generation out from the session lock, instead
running it under a per-dylib generator lock. It also makes the
DefinitionGenerator::tryToGenerate method optionally asynchronous: Generators
are handed an opaque LookupState object which can be captured to stop/restart
the lookup process.
The new scheme provides the following benefits and guarantees:
(1) Queries that do not need to attempt definition generation (because all
requested symbols matched against existing definitions in the JITDylib)
can proceed without being blocked by any running definition generators.
(2) Definition generators can capture the LookupState to continue their work
asynchronously. This allows generators to run for an arbitrary amount of
time without blocking a thread. Definition generators that do not need to
run asynchronously can return without capturing the LookupState to eliminate
unnecessary recursion and improve lookup performance.
(3) Definition generators still do not need to worry about concurrency or
re-entrance: Since they are still run under a (per-dylib) lock, generators
will never be re-entered concurrently, or given overlapping symbol sets to
generate.
Finally, the new system distinguishes between symbols that are candidates for
generation (generation candidates) and symbols that failed to match for a query
(due to symbol visibility). This fixes a bug where an unresolved symbol could
trigger generation of a duplicate definition for an existing hidden symbol.
MaterializationResponsibility, JITDylib, and ExecutionSession collectively
manage the OrcV2 core JIT state. Responsibility for maintaining and
updating this state has previously been spread among these classes, resulting
in implementations that are each non-trivial, but all tightly coupled. This has
in turn made reading the code and reasoning about state update and locking
rules difficult.
The core state model can be simplified by thinking of
MaterializationResponsibility and JITDylib as facets of ExecutionSession. This
commit is the first in a series intended to refactor Core.cpp to reflect this
model. Operations on MaterializationResponsibility and JITDylib will forward to
implementation methods inside ExecutionSession. Raw state will remain with the
original classes, but in most cases will only be modified by the
ExecutionSession.
This patch updates the Kaleidoscope and BuildingAJIT tutorial series (chapter
1-4) to OrcV2. Chapter 5 of the BuildingAJIT series is removed -- it will be
re-instated once we have in-tree support for out-of-process JITing.
This patch only updates the tutorial code, not the text. Patches welcome for
that, otherwise I will try to update it in a few weeks.
This patch introduces new APIs to support resource tracking and removal in Orc.
It is intended as a thread-safe generalization of the removeModule concept from
OrcV1.
Clients can now create ResourceTracker objects (using
JITDylib::createResourceTracker) to track resources for each MaterializationUnit
(code, data, aliases, absolute symbols, etc.) added to the JIT. Every
MaterializationUnit will be associated with a ResourceTracker, and
ResourceTrackers can be re-used for multiple MaterializationUnits. Each JITDylib
has a default ResourceTracker that will be used for MaterializationUnits added
to that JITDylib if no ResourceTracker is explicitly specified.
Two operations can be performed on ResourceTrackers: transferTo and remove. The
transferTo operation transfers tracking of the resources to a different
ResourceTracker object, allowing ResourceTrackers to be merged to reduce
administrative overhead (the source tracker is invalidated in the process). The
remove operation removes all resources associated with a ResourceTracker,
including any symbols defined by MaterializationUnits associated with the
tracker, and also invalidates the tracker. These operations are thread safe, and
should work regardless of the the state of the MaterializationUnits. In the case
of resource transfer any existing resources associated with the source tracker
will be transferred to the destination tracker, and all future resources for
those units will be automatically associated with the destination tracker. In
the case of resource removal all already-allocated resources will be
deallocated, any if any program representations associated with the tracker have
not been compiled yet they will be destroyed. If any program representations are
currently being compiled then they will be prevented from completing: their
MaterializationResponsibility will return errors on any attempt to update the
JIT state.
Clients (usually Layer writers) wishing to track resources can implement the
ResourceManager API to receive notifications when ResourceTrackers are
transferred or removed. The MaterializationResponsibility::withResourceKeyDo
method can be used to create associations between the key for a ResourceTracker
and an allocated resource in a thread-safe way.
RTDyldObjectLinkingLayer and ObjectLinkingLayer are updated to use the
ResourceManager API to enable tracking and removal of memory allocated by the
JIT linker.
The new JITDylib::clear method can be used to trigger removal of every
ResourceTracker associated with the JITDylib (note that this will only
remove resources for the JITDylib, it does not run static destructors).
This patch includes unit tests showing basic usage. A follow-up patch will
update the Kaleidoscope and BuildingAJIT tutorial series to OrcV2 and will
use this API to release code associated with anonymous expressions.
This removes all legacy layers, legacy utilities, the old Orc C bindings,
OrcMCJITReplacement, and OrcMCJITReplacement regression tests.
ExecutionEngine and MCJIT are not affected by this change.
Making MaterializationResponsibility instances immovable allows their
associated VModuleKeys to be updated by the ExecutionSession while the
responsibility is still in-flight. This will be used in the upcoming
removable code feature to enable safe merging of resource keys even if
there are active compiles using the keys being merged.
TPCDynamicLibrarySearchGenerator was generating errors on missing
symbols, but that doesn't fit the DefinitionGenerator contract: A symbol
that isn't generated by a particular generator should not cause an
error.
This commit fixes the error by using SymbolLookupFlags::WeaklyReferencedSymbol
for all elements of the lookup, and switches llvm-jitlink to use
TPCDynamicLibrarySearchGenerator.
If there's no initializer symbol in the current MaterializationResponsibility
then bail out without installing JITLink passes: they're going to be no-ops
anyway.
A think-o in the existing code meant that dependencies were never registered.
This failure could lead to crashes rather than orderly error propagation if
initialization dependencies failed to materialize.
No test case: The bug was discovered in an out-of-tree code and requires
pathalogically misconfigured JIT to generate the original error that lead to
the crash.
DFS and Reverse-DFS linkage orders are used to order execution of
deinitializers and initializers respectively.
This patch replaces uses of special purpose DFS order functions in
MachOPlatform and LLJIT with uses of the new methods.
This loop caused me a little headache once, because I didn't see the assigned variable is a member. The refactored version appears more readable to me.
Differential Revision: https://reviews.llvm.org/D85922
Archives can now be specified as input files the same way that object
files are. Archives will always be linked after all objects (regardless
of the relative order of the inputs) but before any dynamic libraries or
process symbols.
This patch also relaxes matching for slice triples in
StaticLibraryDefinitionGenerator in order to support this feature:
Vendors need not match if the source vendor is unknown.
This allows clients to detect invalid transformations applied by JITLink passes
(e.g. inserting or removing symbols in unexpected ways) and terminate linking
with an error.
This change is used to simplify the error propagation logic in
ObjectLinkingLayer.
Subclasses will commonly gather that information from a remote during
construction, in which case they won't have meaningful values to pass to
TargetProcessControl's constructor.
This patch makes ownership of the JITLinkMemoryManager by ObjectLinkingLayer
optional: the layer can still own the memory manager but no longer has to.
Evevntually we want to move to a state where ObjectLinkingLayer never owns its
memory manager. For now allowing optional ownership makes it easier to develop
classes that can dynamically use either RTDyldObjectLinkingLayer, which owns
its memory managers, or ObjectLinkingLayer (e.g. LLJIT).
TPCDynamicLibrarySearchGenerator uses a TargetProcessControl instance to
load libraries and search for symbol addresses in a target process. It
can be used in place of a DynamicLibrarySearchGenerator to enable
target-process agnostic lookup.
TargetProcessControl is a new API for communicating with JIT target processes.
It supports memory allocation and access, and inspection of some process
properties, e.g. the target proces triple and page size.
Centralizing these APIs allows utilities written against TargetProcessControl
to remain independent of the communication procotol with the target process
(which may be direct memory access/allocation for in-process JITing, or may
involve some form of IPC or RPC).
An initial set of TargetProcessControl-based utilities for lazy compilation is
provided by the TPCIndirectionUtils class.
An initial implementation of TargetProcessControl for in-process JITing
is provided by the SelfTargetProcessControl class.
An example program showing how the APIs can be used is provided in
llvm/examples/OrcV2Examples/LLJITWithTargetProcessControl.
Summary: This PR contains a build failure fix that occurs on both AIX and z/OS as a result of this commit https://reviews.llvm.org/rG670915094462d831e3733e5b01a76471b8cf6dd8.
Reviewers: uweigand, Kai, hubert.reinterpretcast, daltenty, lhames
Reviewed By: Kai, hubert.reinterpretcast, daltenty
Subscribers: SeanP, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83889
destructor via a pointer of the wrong static type.
This caused crashes during deallocation in C++14 builds when using a
deallocator whose sized delete requires the size argument to be correct.
Also make the LazyCallThroughManager destructor protected to catch this
sort of bug in the future.
LazyReexportsManager instances use the trampoline pool, but they don't need to
own it. Keeping TrampolinePool ownership separate allows re-use of the
trampoline pool by other clients.
This patch generalizes the APIs for writing re-entry blocks, trampolines and
stubs to allow their final linked address to differ from the address of
their initial working memory. This will allow these routines to be used with
JITLinkMemoryManagers, which will in turn allow for unification of code paths
for in-process and cross-process lazy JITing.
JITLink supports all code and relocation models, so there's no reason to
conditionalize using JITLink on the code or relocation model settings.
Clients wanting to use RTDyldObjectLinkingLayer/RuntimeDyld will now
need to use a custom object linking layer creator.
MaterializationResponsibility.
MaterializationResponsibility objects provide a connection between a
materialization process (compiler, jit linker, etc.) and the JIT state held in
the ExecutionSession and JITDylib objects. Switching to shared ownership
extends the lifetime of JITDylibs to ensure they remain accessible until all
materializers targeting them have completed. This will allow (in a follow-up
patch) JITDylibs to be removed from the ExecutionSession and placed in a
pending-destruction state while they are kept alive to communicate errors
to/from any still-runnning materialization processes. The intent is to enable
JITDylibs to be safely removed even if they have running compiles targeting
them.
Refering to the link order of a dylib better matches the terminology used in
static compilation. As upcoming patches will increase the number of places where
link order matters (for example when closing JITDylibs) it's better to get this
name change out of the way early.
