The existing lookup uses a hash table with the type's mangled name as the key. Building that key is costly. Add a new table that uses pointer keys, so that we can use the descriptor and arguments directly as the key.
rdar://127621414
Read a list of disabled process names from the prespecializations library, and turn the feature off if the current process matches. Also allow passing process names in environment variables. Processes can be disabled by name using SWIFT_DEBUG_LIB_PRESPECIALIZED_DISABLED_PROCESSES, and a disable can be overridden with SWIFT_DEBUG_LIB_PRESPECIALIZED_ENABLED_PROCESSES.
rdar://126216786
The descriptor and arguments for prespecialized metadata will always be in the shared cache. Skip creating the mangling for any lookup involving pointers outside the shared cache, as an optimization.
We need to check for overridden images on every image load, otherwise
XCTest (among others) may `dlopen()` an image that pulls in something
that is overridden, at which point the prespecialized metadata won't
match the image we loaded.
rdar://125727356
When we fail to look up a type by name, we print an error, then try to compare anyway, which crashes. Skip the comparison when that happens.
While we're in there, modify _swift_validatePrespecializedMetadata to be more useful for debugging, by removing the parameters and having it print the results directly.
Have SWIFT_DEBUG_LIB_PRESPECIALIZED_PATH use dlopen with RTLD_NOLOAD. We don't want it to allow loading arbitrary dylibs. Instead, a user can use something like DYLD_INSERT_LIBRARIES to load the dylib, which we will then pick up in the runtime, and processes that deny DYLD_INSERT_LIBRARIES will not be able to work around it with SWIFT_DEBUG_LIB_PRESPECIALIZED_PATH.
rdar://123643585
We run the builder, then use a small program that converts the JSON output into C code that generates the data. Compile that into a bundle, then load it as the prespecializations library. Then scan all the entries in the table and compare them with what the runtime builds dynamically.
We were doing a linear scan of the table contents as a stopgap. Stop doing that, and compute the proper key for the lookup, matching the one used in the builder.
This library uses GenericMetadataBuilder with a ReaderWriter that can read data and resolve pointers from MachO files, and emit a JSON representation of a dylib containing the built metadata.
We use LLVM's binary file readers to parse the MachO files and resolve fixups so we can follow pointers. This code is somewhat MachO specific, but could be generalized to other formats that LLVM supports.
rdar://116592577
