runFinalizeActions takes an AllocActions vector and attempts to run its finalize
actions. If any finalize action fails then all paired dealloc actions up to the
failing pair are run, and the error(s) returned. If all finalize actions succeed
then a vector containing the dealloc actions is returned.
runDeallocActions takes a vector<WrapperFunctionCall> containing dealloc action
calls and runs them all, returning any error(s).
These helpers are intended to simplify the implementation of
JITLinkMemoryManager::InFlightAlloc::finalize and
JITLinkMemoryManager::deallocate overrides by taking care of execution (and
potential roll-back) of allocation actions.
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.
This reapplies e1933a0488 (which was reverted in
f55ba3525e due to bot failures, e.g.
https://lab.llvm.org/buildbot/#/builders/117/builds/2768).
The bot failures were due to a missing symbol error: We use the input object's
mangling to decide how to mangle the debug-info registration function name. This
caused lookup of the registration function to fail when the input object
mangling didn't match the host mangling.
Disbaling the test on non-Darwin platforms is the easiest short-term solution.
I have filed https://llvm.org/PR52503 with a proposed longer term solution.
This commit adds a new plugin, GDBJITDebugInfoRegistrationPlugin, that checks
for objects containing debug info and registers any debug info found via the
GDB JIT registration API.
To enable this registration without redundantly representing non-debug sections
this plugin synthesizes a new embedded object within a section of the LinkGraph.
An allocation action is used to make the registration call.
Currently MachO only. ELF users can still use the DebugObjectManagerPlugin. The
two are likely to be merged in the near future.
We need to skip the length field when generating error strings.
No test case: This hand-hacked deserializer should be removed in the near future
once JITLink can use generic ORC APIs (including SPS and WrapperFunction).
Alloc actions should return a CWrapperFunctionResult. JITLink does not have
access to this type yet, due to library layering issues, so add a cut-down
version with a fixme.
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.
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
GCC warning:
```
In file included from /usr/include/c++/9/cassert:44,
from /home/vsts/work/1/llvm-project/llvm/include/llvm/ADT/BitVector.h:21,
from /home/vsts/work/1/llvm-project/llvm/include/llvm/Support/Program.h:17,
from /home/vsts/work/1/llvm-project/llvm/include/llvm/Support/Process.h:32,
from /home/vsts/work/1/llvm-project/llvm/lib/ExecutionEngine/JITLink/JITLinkMemoryManager.cpp:11:
/home/vsts/work/1/llvm-project/llvm/lib/ExecutionEngine/JITLink/JITLinkMemoryManager.cpp: In member function ‘virtual llvm::Expected<std::unique_ptr<llvm::jitlink::JITLinkMemoryManager::Allocation> > llvm::jitlink::InProcessMemoryManager::allocate(const llvm::jitlink::JITLinkDylib*, const SegmentsRequestMap&)’:
/home/vsts/work/1/llvm-project/llvm/lib/ExecutionEngine/JITLink/JITLinkMemoryManager.cpp:129:40: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
129 | assert(SlabRemaining.allocatedSize() >= 0 && "Mapping exceeds allocation");
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
```
The return type of `allocatedSize()` is `size_t`, thus the expression
`SlabRemaining.allocatedSize() >= 0` always evaluate to `true`.
JITLinkDylib represents a target dylib for a JITLink link. By representing this
explicitly we can:
- Enable JITLinkMemoryManagers to manage allocations on a per-dylib basis
(e.g by maintaining a seperate allocation pool for each JITLinkDylib).
- Enable new features and diagnostics that require information about the
target dylib (not implemented in this patch).
reinterpret_cast'ing the block base address directly to a uint64_t leaves the
high bits in an implementation-defined state, but JITLink expects them to be
zero. Switching to pointerToJITTargetAddress for the cast should fix this.
This should fix the jitlink test failures that we have seen on some of the
32-bit testers.
InProcessMemoryManager used to make separate memory allocation calls for each
permission level (RW, RX, RO), which could lead to target-out-of-range errors
if data and code were placed too far apart (this was the source of failures in
the JITLink/AArch64 testcase when it was first landed).
This patch updates InProcessMemoryManager to allocate a single slab which is
subdivided between text and data. This should guarantee that accesses remain
in-range provided that individual object files do not exceed 1Mb in size.
This patch also re-enables the JITLink/AArch64 testcase.
llvm-svn: 374948
In the Atom model the symbols, content and relocations of a relocatable object
file are represented as a graph of atoms, where each Atom represents a
contiguous block of content with a single name (or no name at all if the
content is anonymous), and where edges between Atoms represent relocations.
If more than one symbol is associated with a contiguous block of content then
the content is broken into multiple atoms and layout constraints (represented by
edges) are introduced to ensure that the content remains effectively contiguous.
These layout constraints must be kept in mind when examining the content
associated with a symbol (it may be spread over multiple atoms) or when applying
certain relocation types (e.g. MachO subtractors).
This patch replaces the Atom model in JITLink with a blocks-and-symbols model.
The blocks-and-symbols model represents relocatable object files as bipartite
graphs, with one set of nodes representing contiguous content (Blocks) and
another representing named or anonymous locations (Symbols) within a Block.
Relocations are represented as edges from Blocks to Symbols. This scheme
removes layout constraints (simplifying handling of MachO alt-entry symbols,
and hopefully ELF sections at some point in the future) and simplifies some
relocation logic.
llvm-svn: 373689
Lang Hames