This re-applies 133f86e954, which was reverted in
c5965a411c while I investigated bot failures.
The original failure contained an arithmetic conversion think-o (on line 419 of
EHFrameSupport.cpp) that could cause failures on 32-bit platforms. The issue
should be fixed in this patch.
Adds explicit narrowing casts to JITLinkMemoryManager.cpp.
Honors -slab-address option in llvm-jitlink.cpp, which was accidentally
dropped in the refactor.
This effectively reverts commit 6641d29b70.
This commit substantially refactors the JITLinkMemoryManager API to: (1) add
asynchronous versions of key operations, (2) give memory manager implementations
full control over link graph address layout, (3) enable more efficient tracking
of allocated memory, and (4) support "allocation actions" and finalize-lifetime
memory.
Together these changes provide a more usable API, and enable more powerful and
efficient memory manager implementations.
To support these changes the JITLinkMemoryManager::Allocation inner class has
been split into two new classes: InFlightAllocation, and FinalizedAllocation.
The allocate method returns an InFlightAllocation that tracks memory (both
working and executor memory) prior to finalization. The finalize method returns
a FinalizedAllocation object, and the InFlightAllocation is discarded. Breaking
Allocation into InFlightAllocation and FinalizedAllocation allows
InFlightAllocation subclassses to be written more naturally, and FinalizedAlloc
to be implemented and used efficiently (see (3) below).
In addition to the memory manager changes this commit also introduces a new
MemProt type to represent memory protections (MemProt replaces use of
sys::Memory::ProtectionFlags in JITLink), and a new MemDeallocPolicy type that
can be used to indicate when a section should be deallocated (see (4) below).
Plugin/pass writers who were using sys::Memory::ProtectionFlags will have to
switch to MemProt -- this should be straightworward. Clients with out-of-tree
memory managers will need to update their implementations. Clients using
in-tree memory managers should mostly be able to ignore it.
Major features:
(1) More asynchrony:
The allocate and deallocate methods are now asynchronous by default, with
synchronous convenience wrappers supplied. The asynchronous versions allow
clients (including JITLink) to request and deallocate memory without blocking.
(2) Improved control over graph address layout:
Instead of a SegmentRequestMap, JITLinkMemoryManager::allocate now takes a
reference to the LinkGraph to be allocated. The memory manager is responsible
for calculating the memory requirements for the graph, and laying out the graph
(setting working and executor memory addresses) within the allocated memory.
This gives memory managers full control over JIT'd memory layout. For clients
that don't need or want this degree of control the new "BasicLayout" utility can
be used to get a segment-based view of the graph, similar to the one provided by
SegmentRequestMap. Once segment addresses are assigned the BasicLayout::apply
method can be used to automatically lay out the graph.
(3) Efficient tracking of allocated memory.
The FinalizedAlloc type is a wrapper for an ExecutorAddr and requires only
64-bits to store in the controller. The meaning of the address held by the
FinalizedAlloc is left up to the memory manager implementation, but the
FinalizedAlloc type enforces a requirement that deallocate be called on any
non-default values prior to destruction. The deallocate method takes a
vector<FinalizedAlloc>, allowing for bulk deallocation of many allocations in a
single call.
Memory manager implementations will typically store the address of some
allocation metadata in the executor in the FinalizedAlloc, as holding this
metadata in the executor is often cheaper and may allow for clean deallocation
even in failure cases where the connection with the controller is lost.
(4) Support for "allocation actions" and finalize-lifetime memory.
Allocation actions are pairs (finalize_act, deallocate_act) of JITTargetAddress
triples (fn, arg_buffer_addr, arg_buffer_size), that can be attached to a
finalize request. At finalization time, after memory protections have been
applied, each of the "finalize_act" elements will be called in order (skipping
any elements whose fn value is zero) as
((char*(*)(const char *, size_t))fn)((const char *)arg_buffer_addr,
(size_t)arg_buffer_size);
At deallocation time the deallocate elements will be run in reverse order (again
skipping any elements where fn is zero).
The returned char * should be null to indicate success, or a non-null
heap-allocated string error message to indicate failure.
These actions allow finalization and deallocation to be extended to include
operations like registering and deregistering eh-frames, TLS sections,
initializer and deinitializers, and language metadata sections. Previously these
operations required separate callWrapper invocations. Compared to callWrapper
invocations, actions require no extra IPC/RPC, reducing costs and eliminating
a potential source of errors.
Finalize lifetime memory can be used to support finalize actions: Sections with
finalize lifetime should be destroyed by memory managers immediately after
finalization actions have been run. Finalize memory can be used to support
finalize actions (e.g. with extra-metadata, or synthesized finalize actions)
without incurring permanent memory overhead.
Wrapper function call and dispatch handler helpers are moved to
ExecutionSession, and existing EPC-based tools are re-written to take an
ExecutionSession argument instead.
Requiring an ExecutorProcessControl instance simplifies existing EPC based
utilities (which only need to take an ES now), and should encourage more
utilities to use the EPC interface. It also simplifies process termination,
since the session can automatically call ExecutorProcessControl::disconnect
(previously this had to be done manually, and carefully ordered with the
rest of JIT tear-down to work correctly).
This is separate from (but builds on) the support added in ec6b71df70 for
emitting LinkGraphs in the context of an active materialization. This commit
makes LinkGraphs a first-class data structure with features equivalent to
object files within ObjectLinkingLayer.
The current ObjectLinkingLayer (now RTDyldObjectLinkingLayer) links objects
in-process using MCJIT's RuntimeDyld class. In the near future I hope to add new
object linking layers (e.g. a remote linking layer that links objects in the JIT
target process, rather than the client), so I'm renaming this class to be more
descriptive.
llvm-svn: 295636
This patch replaces RuntimeDyld::SymbolInfo with JITSymbol: A symbol class
that is capable of lazy materialization (i.e. the symbol definition needn't be
emitted until the address is requested). This can be used to support common
and weak symbols in the JIT (though this is not implemented in this patch).
For consistency, RuntimeDyld::SymbolResolver is renamed to JITSymbolResolver.
For space efficiency a new class, JITEvaluatedSymbol, is introduced that
behaves like the old RuntimeDyld::SymbolInfo - i.e. it is just a pair of an
address and symbol flags. Instances of JITEvaluatedSymbol can be used in
symbol-tables to avoid paying the space cost of the materializer.
llvm-svn: 277386
This tidies up some code that was manually constructing RuntimeDyld::SymbolInfo
instances from JITSymbols. It will save more mess in the future when
JITSymbol::getAddress is extended to return an Expected<TargetAddress> rather
than just a TargetAddress, since we'll be able to embed the error checking in
the conversion.
llvm-svn: 271350
At the same time, fixes InstructionsTest::CastInst unittest: yes
you can leave the IR in an invalid state and exit when you don't
destroy the context (like the global one), no longer now.
This is the first part of http://reviews.llvm.org/D19094
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266379
they're needed.
Prior to this patch objects were loaded (via RuntimeDyld::loadObject) when they
were added to the ObjectLinkingLayer, but were not relocated and finalized until
a symbol address was requested. In the interim, another object could be loaded
and finalized with the same memory manager, causing relocation/finalization of
the first object to fail (as the first finalization call may have marked the
allocated memory for the first object read-only).
By deferring the loadObject call (and subsequent memory allocations) until an
object file is needed we can avoid prematurely finalizing memory.
llvm-svn: 258185
llvm\unittests\ExecutionEngine\Orc\ObjectLinkingLayerTest.cpp(115) : error C2327: 'llvm::OrcExecutionTest::TM' : is not a type name, static, or enumerator
llvm\unittests\ExecutionEngine\Orc\ObjectLinkingLayerTest.cpp(115) : error C2065: 'TM' : undeclared identifier
FYI, "this->TM" was valid even before moving class SectionMemoryManagerWrapper.
llvm-svn: 257290
managers.
Prior to this patch, recursive finalization (where finalization of one
RuntimeDyld instance triggers finalization of another instance on which the
first depends) could trigger memory access failures: When the inner (dependent)
RuntimeDyld instance and its memory manager are finalized, memory allocated
(but not yet relocated) by the outer instance is locked, and relocation in the
outer instance fails with a memory access error.
This patch adds a latch to the RuntimeDyld::MemoryManager base class that is
checked by a new method: RuntimeDyld::finalizeWithMemoryManagerLocking, ensuring
that shared memory managers are only finalized by the outermost RuntimeDyld
instance.
This allows ORC clients to supply the same memory manager to multiple calls to
addModuleSet. In particular it enables the use of user-supplied memory managers
with the CompileOnDemandLayer which must reuse the supplied memory manager for
each function that is lazily compiled.
llvm-svn: 257263
Lang Hames