CompactUnwindSplitter splits compact-unwind sections on record boundaries and
adds keep-alive edges from target functions back to their respective records.
In MachO_arm64.cpp, a CompactUnwindSplitter pass is added to the pre-prune pass
list when setting up the standard pipeline.
This patch does not provide runtime support for compact-unwind, but is a first
step towards enabling it.
The getPerDylibResources method may be called concurrently from multiple
threads, so we need to protect access to the underlying map.
Possible for fix https://llvm.org/PR51064
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.
This reintroduces "[ORC] Introduce EPCGenericRTDyldMemoryManager."
(bef55a2b47) and "[lli] Add ChildTarget dependence
on OrcTargetProcess library." (7a219d801b) which were
reverted in 99951a5684 due to bot failures.
The root cause of the bot failures should be fixed by "[ORC] Fix uninitialized
variable." (0371049277) and "[ORC] Wait for
handleDisconnect to complete in SimpleRemoteEPC::disconnect."
(320832cc9b).
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.
This reverts commit bef55a2b47 while I investigate
failures on some bots. Also reverts "[lli] Add ChildTarget dependence on
OrcTargetProcess library." (7a219d801b) which was
a fallow-up to bef55a2b47.
EPCGenericRTDyldMemoryMnaager is an EPC-based implementation of the
RuntimeDyld::MemoryManager interface. It enables remote-JITing via EPC (backed
by a SimpleExecutorMemoryManager instance on the executor side) for RuntimeDyld
clients.
The lli and lli-child-target tools are updated to use SimpleRemoteEPC and
SimpleRemoteEPCServer (rather than OrcRemoteTargetClient/Server), and
EPCGenericRTDyldMemoryManager for MCJIT tests.
By enabling remote-JITing for MCJIT and RuntimeDyld-based ORC clients,
EPCGenericRTDyldMemoryManager allows us to deprecate older remote-JITing
support, including OrcTargetClient/Server, OrcRPCExecutorProcessControl, and the
Orc RPC system itself. These will be removed in future patches.
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.
This should have been included with ExecutorBootstrapService in 78b083dbb7,
but was accidentally left out. It give services a chance to release any
resources that they have acquired.
Two typos, one unsused include and some leftovers from the TargetProcessControl -> ExecutorProcessControl renaming
Reviewed By: xgupta
Differential Revision: https://reviews.llvm.org/D110260
Following D109516, this patch re-uses the new helper function for ELF relocation traversal in the RISCV backend.
Reviewed By: StephenFan
Differential Revision: https://reviews.llvm.org/D109522
Following D109516, this patch re-uses the new helper function for ELF relocation traversal in the x86-64 backend.
Reviewed By: StephenFan
Differential Revision: https://reviews.llvm.org/D109520
This commit fixes an order-of-initialization issue: If the default mmapper
object is destroyed while some global SectionMemoryManager is still using it
then calls to the mapper from ~SectionMemoryManager will fail. This issue was
causing failures when running the LLVM Kaleidoscope examples on windows.
Switching to a ManagedStatic solves the initialization order issue.
Patch by Justice Adams. Thanks Justice!
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D107087
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.
First step in reducing redundancy in `addRelocations()` implementations across ELF JITLink backends. The patch factors out common logic for ELF relocation traversal into the new helper function `forEachRelocation()` in the `ELFLinkGraphBuilder` base class. For now, this is applied to the Aarch64 implementation. Others may follow soon.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D109516
This patch use the same way as the https://reviews.llvm.org/rGfe1fa43f16beac1506a2e73a9f7b3c81179744eb to handle the thread local variable.
It allocates 2 * pointerSize space in GOT to represent the thread key and data address. Instead of using the _tls_get_addr function, I customed a function __orc_rt_elfnix_tls_get_addr to get the address of thread local varible. Currently, this is a wip patch, only one TLS relocation R_X86_64_TLSGD is supported and I need to add the corresponding test cases.
To allocate the TLS descriptor in GOT, I need to get the edge kind information in PerGraphGOTAndPLTStubBuilder, So I add a `Edge::Kind K` argument in some functions in PerGraphGOTAndPLTStubBuilder.h. If it is not suitable, I can think further to solve this problem.
Differential Revision: https://reviews.llvm.org/D109293
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.
Refactors copyBlockContentToWorkingMemory to use offsets rather than direct
pointers to working memory. This simplifies the problem of maintaining
alignments between blocks in working memory, without requiring the working
memory itself to be aligned.
Set up basic infrastructure for 64-bit ARM architecture support in JITLink. It allows for loading a minimal object file and resolving a single relocation. Advanced features like GOT and PLT handling or relaxations were intentionally left out for the moment.
This patch follows the idea to keep implementations for ARM (32-bit) and Aaarch64 (64-bit) separate, because:
* it might be easier to share code with the MachO "arm64" JITLink backend
* LLVM has individual targets for ARM and Aaarch64 as well
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D108986
All ExecutorProcessControl subclasses must provide a JITLinkMemoryManager object
that can be used to allocate memory in the executor process. The
EPCGenericJITLinkMemoryManager class provides an off-the-shelf
JITLinkMemoryManager implementation for JITs that do not need (or cannot
provide) a specialized JITLinkMemoryManager implementation. This simplifies the
process of creating new ExecutorProcessControl implementations.
This patch add the R_RISCV_GOT_HI20 and R_RISCV_CALL_PLT relocation support. And the basic got/plt was implemented. Because of riscv32 and riscv64 has different pointer size, the got entry size and instructions of plt entry is different. This patch is the basic support, the optimization pass at preFixup stage has not been implemented.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D107688
This was already the case, but the recent change (957334382c) altered
the behavior on some of our bots where __unw_add_dynamic_fde is not
found. This restores the prior behavior on Darwin while also retaining
the new behavior from that change.
This patch supported the R_X86_64_32S relocation and add the Pointer32Signed generic edge kind.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D108446
All ExecutorProcessControl subclasses must provide an
ExecutorProcessControl::MemoryAccess object that can be used to access executor
memory from the JIT process. The EPCGenericMemoryAccess class provides an
off-the-shelf MemoryAccess implementation for JITs that do not need (or cannot
provide) a specialized MemoryAccess implementation. This simplifies the process
of creating new ExecutorProcessControl implementations.
This prevents the async methods (which shoud be overridden by subclasses) from
hiding the blocking helper methods, avoiding a lot of 'using MemoryAccess::...'
boilerplate.
Accepts a vector of (SymbolStringPtr, ExecutorAddress*) pairs, looks up all the
symbols, then writes their address to each of the corresponding
ExecutorAddresses.
This idiom (looking up and recording addresses into a specific set of variables)
is used in MachOPlatform and the (temporarily reverted) ELFNixPlatform, and is
likely to be used in other places in the near future, so wrapping it in a
utility function should save us some boilerplate.
This patch optimize the GOTPCRELX Reloations, which is described in X86-64 psabi chapter B.2. And Not all optimization of this chapter is implemented.
1. Convert call and jmp has been implemented
2. Convert mov, but the optimization that when the symbol is defined in the lower 32-bit address space, memory operand in `mov` can be convertted into immediate operand has not been implemented.
3. Conver Test and Binop has not been implemented.
The new test file named ELF_got_plt_optimizations.s has been added, and I moved some test cases about optimization of got/plt from ELF_x86_64_small_pic_relocations.s to the new test file.
By referencing the lld, so, the optimization `Convert call and jmp` is not same as what psabi says, and I have explained it in the comment.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D108280
This change adds support to ORCv2 and the Orc runtime library for static
initializers, C++ static destructors, and exception handler registration for
ELF-based platforms, at present Linux and FreeBSD on x86_64. It is based on the
MachO platform and runtime support introduced in bb5f97e3ad.
Patch by Peter Housel. Thanks very much Peter!
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D108081
libgcc and libunwind have different flavours of __register_frame. Both
flavours are already correctly handled, except that the code to handle
the libunwind flavour is guarded by __APPLE__. This change uses the
presence of __unw_add_dynamic_fde in libunwind instead to detect whether
libunwind is used, rather than hardcoding it as Apple vs. non-Apple.
Fixes PR44074.
Thanks to Albert Jin <albert.jin@gmail.com> and Chris Schafmeister
<chris.schaf@verizon.net> for identifying the problem.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D106129
This patch unify optimizeELF_x86_64_GOTAndStubs and optimizeMachO_x86_64_GOTAndStubs into a pure optimize_x86_64_GOTAndStubs
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D108025
This patch uses a switch statement to map the ELF_x86_64's edge kind to generic edge kind, and merge the ELF_x86_64 's applyFixup function to the x86_64 's applyFixup function. Some edge kinds were not have corresponding generic edge kinds, so I added three generic edge kinds asa follows:
1. RequestGOTAndTransformToDelta64, which is similar to RequestGOTAndTransformToDelta32.
2. GOTDelta64. This generic kind is similar to Delta64, except the GOTDelta64 computes the delta relative to GOTSymbol
3. RequestGOTAndTransformToGOTDelta64. This edge kind was used to deal with ELF_x86_64's GOT64 edge kind, it request the fixGOTEdge function to change the target to GOT entry, and set the edge kind to generic edge kind GOTDelta64.
These added generic edge kinds may named haphazardly, or can't express its meaning well.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D107967
Some files still contained the old University of Illinois Open Source
Licence header. This patch replaces that with the Apache 2 with LLVM
Exception licence.
Differential Revision: https://reviews.llvm.org/D107528
In RISCV's relocations, some relocations are comprised of two relocation types. For example, R_RISCV_PCREL_HI20 and R_RISCV_PCREL_LO12_I compose a PC relative relocation. In general the compiler will set a label in the position of R_RISCV_PCREL_HI20. So, to test the R_RISCV_PCREL_LO12_I relocation, we need decode instruction at position of the label points to R_RISCV_PCREL_HI20 plus 4 (the size of a riscv non-compress instruction).
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D105528
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 patch is the initial support, it implements translation from object file to JIT link graph, and very few relocations were supported. Currently, the test file ELF_pc_indirect.s is passed, the HelloWorld program(compiled with mno-relax flag) can be linked correctly and run on instruction emulator correctly.
In the downstream implementation, I have implemented the GOT, PLT function, and EHFrame and some optimization will be implement soon. I will organize the code in to patches, then gradually send it to upstream.
Differential Revision: https://reviews.llvm.org/D105429
By replacing a lambda expression with a functor class instance, this
patch works around an issue encountered on AIX where the IBM XL compiler
appears to make no progress for many hours.
Reviewed By: jsji
Differential Revision: https://reviews.llvm.org/D106554
This reverts commit 6b2a96285b.
The ccache builders are still failing. Looks like they need to be updated to
get the llvm-zorg config change in 490633945677656ba75d42ff1ca9d4a400b7b243.
I'll re-apply this as soon as the builders are updated.
This reapplies commit a7733e9556 ("Re-apply
[ORC][ORC-RT] Add initial native-TLV support to MachOPlatform."), and
d4abdefc99 ("[ORC-RT] Rename macho_tlv.x86-64.s
to macho_tlv.x86-64.S (uppercase suffix)").
These patches were reverted in 48aa82cacb while I
investigated bot failures (e.g.
https://lab.llvm.org/buildbot/#/builders/109/builds/18981). The fix was to
disable building of the ORC runtime on buliders using ccache (which is the same
fix used for other compiler-rt projects containing assembly code). This fix was
commited to llvm-zorg in 490633945677656ba75d42ff1ca9d4a400b7b243.
This reverts commit d4abdefc99 ("[ORC-RT] Rename
macho_tlv.x86-64.s to macho_tlv.x86-64.S (uppercase suffix)", and
a7733e9556 ("Re-apply "[ORC][ORC-RT] Add initial
native-TLV support to MachOPlatform."), while I investigate failures on
ccache builders (e.g. https://lab.llvm.org/buildbot/#/builders/109/builds/18981)
Reapplies fe1fa43f16, which was reverted in
6d8c63946c, with fixes:
1. Remove .subsections_via_symbols directive from macho_tlv.x86-64.s (it's
not needed here anyway).
2. Return error from pthread_key_create to the MachOPlatform to silence unused
variable warning.
Adds code to LLVM (MachOPlatform) and the ORC runtime to support native MachO
thread local variables. Adding new TLVs to a JITDylib at runtime is supported.
On the LLVM side MachOPlatform is updated to:
1. Identify thread local variables in the LinkGraph and lower them to GOT
accesses to data in the __thread_data or __thread_bss sections.
2. Merge and report the address range of __thread_data and thread_bss sections
to the runtime.
On the ORC runtime a MachOTLVManager class introduced which records the address
range of thread data/bss sections, and creates thread-local instances from the
initial data on demand. An orc-runtime specific tlv_get_addr implementation is
included which saves all register state then calls the MachOTLVManager to get
the address of the requested variable for the current thread.
LinkGraph::transferBlock can be used to move a block and all associated symbols
from one section to another.
LinkGraph::mergeSections moves all blocks and sections from a source section to
a destination section.
Adds support for MachO static initializers/deinitializers and eh-frame
registration via the ORC runtime.
This commit introduces cooperative support code into the ORC runtime and ORC
LLVM libraries (especially the MachOPlatform class) to support macho runtime
features for JIT'd code. This commit introduces support for static
initializers, static destructors (via cxa_atexit interposition), and eh-frame
registration. Near-future commits will add support for MachO native
thread-local variables, and language runtime registration (e.g. for Objective-C
and Swift).
The llvm-jitlink tool is updated to use the ORC runtime where available, and
regression tests for the new MachOPlatform support are added to compiler-rt.
Notable changes on the ORC runtime side:
1. The new macho_platform.h / macho_platform.cpp files contain the bulk of the
runtime-side support. This includes eh-frame registration; jit versions of
dlopen, dlsym, and dlclose; a cxa_atexit interpose to record static destructors,
and an '__orc_rt_macho_run_program' function that defines running a JIT'd MachO
program in terms of the jit- dlopen/dlsym/dlclose functions.
2. Replaces JITTargetAddress (and casting operations) with ExecutorAddress
(copied from LLVM) to improve type-safety of address management.
3. Adds serialization support for ExecutorAddress and unordered_map types to
the runtime-side Simple Packed Serialization code.
4. Adds orc-runtime regression tests to ensure that static initializers and
cxa-atexit interposes work as expected.
Notable changes on the LLVM side:
1. The MachOPlatform class is updated to:
1.1. Load the ORC runtime into the ExecutionSession.
1.2. Set up standard aliases for macho-specific runtime functions. E.g.
___cxa_atexit -> ___orc_rt_macho_cxa_atexit.
1.3. Install the MachOPlatformPlugin to scrape LinkGraphs for information
needed to support MachO features (e.g. eh-frames, mod-inits), and
communicate this information to the runtime.
1.4. Provide entry-points that the runtime can call to request initializers,
perform symbol lookup, and request deinitialiers (the latter is
implemented as an empty placeholder as macho object deinits are rarely
used).
1.5. Create a MachO header object for each JITDylib (defining the __mh_header
and __dso_handle symbols).
2. The llvm-jitlink tool (and llvm-jitlink-executor) are updated to use the
runtime when available.
3. A `lookupInitSymbolsAsync` method is added to the Platform base class. This
can be used to issue an async lookup for initializer symbols. The existing
`lookupInitSymbols` method is retained (the GenericIRPlatform code is still
using it), but is deprecated and will be removed soon.
4. JIT-dispatch support code is added to ExecutorProcessControl.
The JIT-dispatch system allows handlers in the JIT process to be associated with
'tag' symbols in the executor, and allows the executor to make remote procedure
calls back to the JIT process (via __orc_rt_jit_dispatch) using those tags.
The primary use case is ORC runtime code that needs to call bakc to handlers in
orc::Platform subclasses. E.g. __orc_rt_macho_jit_dlopen calling back to
MachOPlatform::rt_getInitializers using __orc_rt_macho_get_initializers_tag.
(The system is generic however, and could be used by non-runtime code).
The new ExecutorProcessControl::JITDispatchInfo struct provides the address
(in the executor) of the jit-dispatch function and a jit-dispatch context
object, and implementations of the dispatch function are added to
SelfExecutorProcessControl and OrcRPCExecutorProcessControl.
5. OrcRPCTPCServer is updated to support JIT-dispatch calls over ORC-RPC.
6. Serialization support for StringMap is added to the LLVM-side Simple Packed
Serialization code.
7. A JITLink::allocateBuffer operation is introduced to allocate writable memory
attached to the graph. This is used by the MachO header synthesis code, and will
be generically useful for other clients who want to create new graph content
from scratch.
At most these use the StringRef/Twine wrappers and don't have any implicit uses of std::string.
Move the include down to any cpp implementation where std::string is actually used.
Renames CommonOrcRuntimeTypes.h to ExecutorAddress.h and moves ExecutorAddress
into the 'orc' namespace (rather than orc::shared).
Also makes ExecutorAddress a class, adds an ExecutorAddrDiff type and some
arithmetic operations on the pair (subtracting two addresses yields an addrdiff,
adding an addrdiff and an address yields an address).
The computeNamedSymbolDependencies and computeLocalDeps methods on
ObjectLinkingLayerJITLinkContext are responsible for computing, for each symbol
in the current MaterializationResponsibility, the set of non-locally-scoped
symbols that are depended on. To calculate this we have to consider the effect
of chains of dependence through locally scoped symbols in the LinkGraph. E.g.
.text
.globl foo
foo:
callq bar ## foo depneds on external 'bar'
movq Ltmp1(%rip), %rcx ## foo depends on locally scoped 'Ltmp1'
addl (%rcx), %eax
retq
.data
Ltmp1:
.quad x ## Ltmp1 depends on external 'x'
In this example symbol 'foo' depends directly on 'bar', and indirectly on 'x'
via 'Ltmp1', which is locally scoped.
Performance of the existing implementations appears to have been mediocre:
Based on flame graphs posted by @drmeister (in #jit on the LLVM discord server)
the computeLocalDeps function was taking up a substantial amount of time when
starting up Clasp (https://github.com/clasp-developers/clasp).
This commit attempts to address the performance problems in three ways:
1. Using jitlink::Blocks instead of jitlink::Symbols as the nodes of the
dependencies-introduced-by-locally-scoped-symbols graph.
Using either Blocks or Symbols as nodes provides the same information, but since
there may be more than one locally scoped symbol per block the block-based
version of the dependence graph should always be a subgraph of the Symbol-based
version, and so faster to operate on.
2. Improved worklist management.
The older version of computeLocalDeps used a fixed worklist containing all
nodes, and iterated over this list propagating dependencies until no further
changes were required. The worklist was not sorted into a useful order before
the loop started.
The new version uses a variable work-stack, visiting nodes in DFS order and
only adding nodes when there is meaningful work to do on them.
Compared to the old version the new version avoids revisiting nodes which
haven't changed, and I suspect it converges more quickly (due to the DFS
ordering).
3. Laziness and caching.
Mappings of...
jitlink::Symbol* -> Interned Name (as SymbolStringPtr)
jitlink::Block* -> Immediate dependencies (as SymbolNameSet)
jitlink::Block* -> Transitive dependencies (as SymbolNameSet)
are all built lazily and cached while running computeNamedSymbolDependencies.
According to @drmeister these changes reduced Clasp startup time in his test
setup (averaged over a handful of starts) from 4.8 to 2.8 seconds (with
ORC/JITLink linking ~11,000 object files in that time), which seems like
enough to justify switching to the new algorithm in the absence of any other
perf numbers.
MachOJITDylibInitializers::SectionExtent represented the address range of a
section as an (address, size) pair. The new ExecutorAddressRange type
generalizes this to an address range (for any object, not necessarily a section)
represented as a (start-address, end-address) pair.
The aim is to express more of ORC (and the ORC runtime) in terms of simple types
that can be serialized/deserialized via SPS. This will simplify SPS-based RPC
involving arguments/return-values of these types.
Adds support for both synchronous and asynchronous calls to wrapper functions
using SPS (Simple Packed Serialization). Also adds support for wrapping
functions on the JIT side in SPS-based wrappers that can be called from the
executor.
These new methods simplify calls between the JIT and Executor, and will be used
in upcoming ORC runtime patches to enable communication between ORC and the
runtime.
This is a first step towards consistently using the term 'executor' for the
process that executes JIT'd code. I've opted for 'executor' as the preferred
term over 'target' as target is already heavily overloaded ("the target
machine for the executor" is much clearer than "the target machine for the
target").
Lang Hames