This reapplies 2cc64df0bd6a802eab592dbc282463c3e4a4281c, which was reverted in
5379c46d490640bfa80283e00240b6f1006092b4 due to bot failures.
The new patch contains fixes to ELFLinkGraphBuilder.h to better handle
non-SHT_ALLOC sections (these were being accidentally skipped in the previous
patch), and to skip SHT_NULL sections.
The original MemDeallocPolicy had two options:
* Standard: allocated memory lives until deallocated or abandoned.
* Finalize: allocated memory lives until all finalize actions have been run,
then is destroyed.
This patch introduces a new 'NoAlloc' option. NoAlloc indicates that the
section should be ignored by the JITLinkMemoryManager -- the memory manager
should allocate neither working memory nor executor address space to blocks in
NoAlloc sections. The NoAlloc option is intended to support metadata sections
(e.g. debug info) that we want to keep in the graph and have fixed up if
necessary, but don't want allocated or transmitted to the executor (or we want
that allocation and transmission to be managed manually by plugins).
Since NoAlloc blocks are ignored by the JITLinkMemoryManager they will not have
working memory allocated to them by default post-allocation. Clients wishing to
modify the content of a block in a NoAlloc section should call
`Block::getMutableMemory(LinkGraph&)` to get writable memory allocated on the
LinkGraph's allocator (this memory will exist for the lifetime of the graph).
If no client requests mutable memory prior to the fixup phase then the generic
link algorithm will do so when it encounters the first edge in any given block.
Addresses of blocks in NoAlloc sections are initialized by the LinkGraph
creator (a LinkGraphBuilder, if the graph is generated from an object file),
and should not be modified by the JITLinkMemoryManager. Plugins are responsible
for updating addresses if they add/remove content from these sections. The
meaning of addresses in NoAlloc-sections is backend/plugin defined, but for
fixup purposes they will be treated the same as addresses in Standard/Finalize
sections. References from Standard/Finalize sections to NoAlloc sections are
expected to be common (these represent metadata tracking executor addresses).
References from NoAlloc sections to Standard/Finalize sections are expected to
be rare/non-existent (they would represent JIT'd code / data tracking metadata
in the controller, which would be surprising). LinkGraphBuilders and specific
backends may impose additional constraints on edges between Standard/Finalize
and NoAlloc sections where required for correctness.
Differential Revision: https://reviews.llvm.org/D146183
This updates the ExecutorSharedMemoryMapperService::deinitialize and
InProcessMemoryMapper::deinitialize methods to deinitialize in reverse order,
bringing them into alignment with the behavior of
InProcessMemoryManager::deallocate and SimpleExecutorMemoryManager::deallocate.
Reverse deinitialization is required because later allocations can depend on
earlier ones.
This fixes failures in the ORC runtime test suite.
When deinitializing, the allocation needs to be removed from the
allocation list of its associated reservation so that remaining
allocations can be deinitialized when releasing the reservation.
Differential Revision: https://reviews.llvm.org/D132313
...with more fixes.
The original patch was reverted in 3e9cc543f22 due to bot failures caused by
a missing dependence on librt. That issue was fixed in 32d8d23cd0, but that
commit also broke sanitizer bots due to a bug in SimplePackedSerialization:
empty ArrayRef<char>s triggered a zero-byte memcpy from a null source. The
ArrayRef<char> serialization issue was fixed in 67220c2ad7, and this patch has
also been updated with a new custom SharedMemorySegFinalizeRequest message that
should avoid serializing empty ArrayRefs in the first place.
https://reviews.llvm.org/D128544
This reverts commit 32d8d23cd0b2d4d010eb112dfe5216f11b2681f9.
Reason: Broke the UBSan buildbots. See more details on Phabricator:
https://reviews.llvm.org/D128544
The original commit was reverted in 3e9cc543f223 due to buildbot failures, which
should be fixed by the addition of dependencies on librt.
Differential Revision: https://reviews.llvm.org/D128544
This is an implementation of orc::MemoryMapper that maps shared memory
pages in both executor and controller process and writes directly to
them avoiding transferring content over EPC. All allocations are properly
deinitialized automatically on the executor side at shutdown by the
ExecutorSharedMemoryMapperService.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D128544
