Add an extra opaque field to AddressSpace, which can be used by clients
of RemoteInspection to distinguish between different address spaces.
LLDB employs an optimization where it reads memory from files instead of
the running process whenever it can to speed up memory reads (these can
be slow when debugging something over a network). To do this, it needs
to keep track whether an address originated from a process or a file. It
currently distinguishes addresses by setting an unused high bit on the
address, but because of pointer authentication this is not a reliable
solution. In order to keep this optimization working, this patch adds an
extra opaque AddressSpace field to RemoteAddress, which LLDB can use on
its own implementation of MemoryReader to distinguish between addresses.
This patch is NFC for the other RemoteInspection clients, as it adds
extra information to RemoteAddress, which is entirely optional and if
unused should not change the behavior of the library.
Although this patch is quite big the changes are largely mechanical,
replacing threading StoredPointer with RemoteAddress.
rdar://148361743
We can end up querying the pointer size and similar things very frequently, which can be slow. These values don't change for any given reader, so call them once and cache the values locally instead.
rdar://150221008
Fix readMetadataBoundsOfSuperclass to recursively apply adjustForSubclass while going through the superclass chain.
Strip indirect descriptor pointers so we can deal with signed pointers here.
Make CMemoryReader assert (in asserts builds) that the addresses being read don't have any signature bits set, which helps track down places where we need to add stripping.
rdar://134448718
The CMemoryReader interface relies on a `GetStringLength` callback, which
returns zero either if the address is invalid or if a valid zero-length
string exists at the given address. We don't want to break ABI with
RemoteMirror, but we can work around this by issuing a one-byte read
at the address and confirming that a null terminator exists there.
* Change the RemoteMirror API to have extensible data layout callback
* Use DLQ_Get prefix on DataLayoutQueryType enum values
* Simplify MemoryReaderImpl and synthesize minimalDataLayoutQueryFunction
This tool should test the usage from SwiftRemoteMirror dylib and
the C API, since that is the public interface from which we're
vending the remote reflection functionality.
Memory readers on the C-side of the API may actually have an object-
oriented design, so they may want to pass an instance to revive
when callbacks make it to the other side of the API boundary.
