orc::SymbolResolver to JITSymbolResolver adapter.
The new orc::SymbolResolver interface uses asynchronous queries for better
performance. (Asynchronous queries with bulk lookup minimize RPC/IPC overhead,
support parallel incoming queries, and expose more available work for
distribution). Existing ORC layers will soon be updated to use the
orc::SymbolResolver API rather than the legacy llvm::JITSymbolResolver API.
Because RuntimeDyld still uses JITSymbolResolver, this patch also includes an
adapter that wraps an orc::SymbolResolver with a JITSymbolResolver API.
llvm-svn: 323073
lookupFlags returns a SymbolFlagsMap for the requested symbols, along with a
set containing the SymbolStringPtr for any symbol not found in the VSO.
The JITSymbolFlags for each symbol will have been stripped of its transient
JIT-state flags (i.e. NotMaterialized, Materializing).
Calling lookupFlags does not trigger symbol materialization.
llvm-svn: 323060
ExternalSymbolMap now stores the string key (rather than using a StringRef),
as the object file backing the key may be removed at any time.
llvm-svn: 323001
Bulk queries reduce IPC/RPC overhead for cross-process JITing and expose
opportunities for parallel compilation.
The two new query methods are lookupFlags, which finds the flags for each of a
set of symbols; and lookup, which finds the address and flags for each of a
set of symbols. (See doxygen comments for more details.)
The existing JITSymbolResolver class is renamed LegacyJITSymbolResolver, and
modified to extend the new JITSymbolResolver class using the following scheme:
- lookupFlags is implemented by calling findSymbolInLogicalDylib for each of the
symbols, then returning the result of calling getFlags() on each of these
symbols. (Importantly: lookupFlags does NOT call getAddress on the returned
symbols, so lookupFlags will never trigger materialization, and lookupFlags will
never call findSymbol, so only symbols that are part of the logical dylib will
return results.)
- lookup is implemented by calling findSymbolInLogicalDylib for each symbol and
falling back to findSymbol if findSymbolInLogicalDylib returns a null result.
Assuming a symbol is found its getAddress method is called to materialize it and
the result (if getAddress succeeds) is stored in the result map, or the error
(if getAddress fails) is returned immediately from lookup. If any symbol is not
found then lookup returns immediately with an error.
This change will break any out-of-tree derivatives of JITSymbolResolver. This
can be fixed by updating those classes to derive from LegacyJITSymbolResolver
instead.
llvm-svn: 322913
version being used on some of the green dragon builders (plus a clang-format).
Workaround: AsynchronousSymbolQuery and VSO want to work with
JITEvaluatedSymbols anyway, so just use them (instead of JITSymbol, which
happens to tickle the bug).
The libcxx bug being worked around was fixed in r276003, and there are plans to
update the offending builders.
llvm-svn: 322140
The original commit broke the builders due to a think-o in an assertion:
AsynchronousSymbolQuery's constructor needs to check the callback member
variables, not the constructor arguments.
llvm-svn: 321853
SymbolSource.
These new APIs are a first stab at tackling some current shortcomings of ORC,
especially in performance and threading support.
VSO (Virtual Shared Object) is a symbol table representing the symbol
definitions of a set of modules that behave as if they had been statically
linked together into a shared object or dylib. Symbol definitions, either
pre-defined addresses or lazy definitions, can be added and queries for symbol
addresses made. The table applies the same linkage strength rules that static
linkers do when constructing a dylib or shared object: duplicate definitions
result in errors, strong definitions override weak or common ones. This class
should improve symbol lookup speed by providing centralized symbol tables (as
compared to the findSymbol implementation in the in-tree ORC layers, which
maintain one symbol table per object file / module added).
AsynchronousSymbolQuery is a query for the addresses of a set of symbols.
Query results are returned via a callback once they become available. Querying
for a set of symbols, rather than one symbol at a time (as the current lookup
scheme does) the JIT has the opportunity to make better use of available
resources (e.g. by spawning multiple jobs to materialize the requested symbols
if possible). Returning results via a callback makes queries asynchronous, so
queries from multiple threads of JIT'd code can proceed simultaneously.
SymbolSource represents a source of symbol definitions. It is used when
adding lazy symbol definitions to a VSO. Symbol definitions can be materialized
when needed or discarded if a stronger definition is found. Materializing on
demand via SymbolSources should (eventually) allow us to remove the lazy
materializers from JITSymbol, which will in turn allow the removal of many
current error checks and reduce the number of RPC round-trips involved in
materializing remote symbols. Adding a discard function allows sources to
discard symbol definitions (or mark them as available_externally), reducing the
amount of redundant code generated by the JIT for ODR symbols.
llvm-svn: 321838
This patch introduces RemoteObjectClientLayer and RemoteObjectServerLayer,
which can be used to forward ORC object-layer operations from a JIT stack in
the client to a JIT stack (consisting only of object-layers) in the server.
This is a new way to support remote-JITing in LLVM. The previous approach
(supported by OrcRemoteTargetClient and OrcRemoteTargetServer) used a
remote-mapping memory manager that sat "beneath" the JIT stack and sent
fully-relocated binary blobs to the server. The main advantage of the new
approach is that relocatable objects can be cached on the server and re-used
(if the code that they represent hasn't changed), whereas fully-relocated blobs
can not (since the addresses they have been permanently bound to will change
from run to run).
llvm-svn: 312511
This patch adds support for thumb relocations to RuntimeDyldMachOARM, and adds
a target-specific flags field to JITSymbolFlags (so that on ARM we can record
whether each symbol is Thumb-mode code).
RuntimeDyldImpl::emitSection is modified to ensure that stubs memory is
correctly aligned based on the size returned by getStubAlignment().
llvm-svn: 310517
This patch updates the ORC layers and utilities to return and propagate
llvm::Errors where appropriate. This is necessary to allow ORC to safely handle
error cases in cross-process and remote JITing.
llvm-svn: 307350
It breaks ExecutionEngine/OrcLazy/weak-function.ll on most bots.
Script:
--
...
--
Exit Code: 1
Command Output (stderr):
--
Could not find main function.
llvm-svn: 277907
This adds partial support for weak functions to the CompileOnDemandLayer by
modifying the addLogicalModule method to check for existing stub definitions
before building a new stub for a weak function. This scheme is sufficient to
support ODR definitions, but fails for general weak definitions if strong
definition is encountered after the first weak definition. (A more extensive
refactor will be required to fully support weak symbols).
This patch does *not* add weak symbol support to RuntimeDyld: I hope to add
that in the near future.
llvm-svn: 277896
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
