Switch the primary implementation of EPC lookupSymbols to be async,
keeping a synchronous wrapper for compatibility. Use the new async
implementation inside EPCDynamicLibrarySearchGenerator to work
working towards a fully async search generator.
Provide an asynchronous lookup API for EPCGenericDylibManager and adopt
that from the SimpleRemoteEPC. This enables an end-to-end async
EPCDynamicLibrarySearchGenerator. Note: currently we keep the current
per-dlhandle lookup model, but a future improvement could do a single
async call for a given lookup operation.
This migrates the dylib manager lookup and related APIs to replace
ExecutorAddress with ExecutorSymbolDef so that in the future we can
model JITSymbolFlags for these symbols. The current change should be NFC
as we are only setting the Exported symbol flag.
Updates tpctypes::DylibHandle to be an ExecutorAddr (rather than a uint64_t),
and SimpleExecutorDylibManager to hold and return raw OS handle values (as
ExecutorAddrs) rather than index values into a map of DynamicLibrary instances.
This will allow clients to use EPCGenericDylibManager in contexts where the
existing DynamicLibrary interface is too limited to be used. (e.g. to look up
JIT symbols in a dylib that was loaded with RTLD_LOCAL).
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.
