The tag was overwritten after resolve when a prior field caused a non-zero offset. This then caused the runtime to treat is a relative instead of an absolute pointer, causing invalid pointers to be dereferenced.
* [IRGen+Runtime] Layout string getEnumTag for fixed size enums subset
getEnumTag impl for layout strings of fixed sized enums that use a function to fetch the enum tag
* Fix potential UB in IRGen
* [IRGen] Handle complex single payload enum cases
rdar://110138498
Handles single payload enum cases with more complex bit patterns (e.g. >64 bits or scattered) by storing a relative pointer to a function that reads the tag.
* Use proper symbol for enum tag helper
* [IRGen] Fix layout string generation for pre-specialized metadata
rdar://108012057
Pre-specialized metadata has to be specifically handled by using the bound generic type instead of the unbound one. All the necessary information is already being passed down as BoundGenericTypeCharacteristics, we just need to apply them when present.
* Add tests and a few fixes
* Fixes after rebase
* Attempt to fix Windows linker issue in test
* [IRGen] Make pointers to accessor functions in layout strings relative
rdar://106319336
Pointers embedded in static layout strings should always be relative, so layout strings can reside in read-only memory.
* Properly handle reference storage ownership
* Pass layout tag and metadata / type layout ppointers separately
* Layout string instantiation fully working
* Fix cases where hasLayoutString flag was not set when it should have
* Update include/swift/ABI/Metadata.h
* [IRGen] Add layout strings for generic and resilient types
rdar://105837048
* Add some corner cases
* Add flag to enable generic instantiation and some fixes
* Fix resilient types
* Fix metadata accessor function pointers in combined layout strings
rdar://105837040
* WIP: Store layout string in type metadata
* WIP: More cases working
* WIP: Layout strings almost working
* Add layout string pointer to struct metadata
* Fetch bytecode layout strings from metadata in runtime
* More efficient bytecode layout
* Add support for interpreted generics in layout strings
* Layout string instantiation, take and more
* Remove duplicate information from layout strings
* Include size of previous object in next objects offset to reduce number of increments at runtime
* Add support for existentials
* Build type layout strings with StructBuilder to support target sizes and metadata pointers
* Add support for resilient types
* Properly cache layout strings in compiler
* Generic resilient types working
* Non-generic resilient types working
* Instantiate resilient type in layout when possible
* Fix a few issues around alignment and signing
* Disable generics, fix static alignment
* Fix MultiPayloadEnum size when no extra tag is necessary
* Fixes after rebase
* Cleanup
* Fix most tests
* Fix objcImplementattion and non-Darwin builds
* Fix BytecodeLayouts on non-Darwin
* Fix Linux build
* Fix sizes in linux tests
* Sign layout string pointers
* Use nullptr instead of debug value
