[RemoteInspection] Add a hook to process addresses before converting

them to hex strings when creating anonymous context descriptors. This
aims to solve a problem when LLDB reads reflection metadata directly
from local binary files instead of downloading them from in-process
memory.

LLDB's MemoryReader implements this to convert the file address into
an in-process address, so mangled names created from instance metadata
can be matched with the field info data read from the local files.

rdar://152743797
(cherry picked from commit 540df14)

Author: adrian-prantl

include/swift/Remote/MemoryReader.h

@@ -150,6 +150,13 @@ class MemoryReader {
     return RemoteAbsolutePointer("", readValue);
   }
 
+  /// Performs the inverse operation of \ref resolvePointer.
+  /// A use-case for this is to turn file addresses into in-process addresses.
+  virtual std::optional<RemoteAddress>
+  resolveRemoteAddress(RemoteAddress address) const {
+    return std::nullopt;
+  }
+
   virtual std::optional<RemoteAbsolutePointer>
   resolvePointerAsSymbol(RemoteAddress address) {
     return std::nullopt;

include/swift/Remote/MetadataReader.h

@@ -2907,8 +2907,10 @@ class MetadataReader {
     case ContextDescriptorKind::Anonymous: {
       // Use the remote address to identify the anonymous context.
       char addressBuf[18];
+      RemoteAddress address(descriptor.getAddressData());
+      address = Reader->resolveRemoteAddress(address).value_or(address);
       snprintf(addressBuf, sizeof(addressBuf), "$%" PRIx64,
-               (uint64_t)descriptor.getAddressData());
+               (uint64_t)address.getAddressData());
       auto anonNode = dem.createNode(Node::Kind::AnonymousContext);
       CharVector addressStr;
       addressStr.append(addressBuf, dem);