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
Until recently, `MemoryReader` had a single function `resovlePointer` which did two things, and has a somewhat vague name. The two things were:
1. Tool-specific mapping between real addresses and tagged addresses (first implemented in `swift-reflection-dump` and then later in lldb)
2. Finding a "symbol" for a given address
Recently, `resolvePointerAsSymbol` was added, which overloaded the term "resolve" and it added another way to deal with symbols for addresses. Symbols themselves were a bit muddled, as `swift-reflection-dump` was dealing with dynamic symbols aka bindings, while lldb was dealing in regular (static) symbols.
This change separates these two parts of functionality, and also divides symbol lookup into two cases. The API surface will now be:
1. `resolvePointer` for mapping/tagging addresses
3. `getSymbol` for looking up a symbol for an address
4. `getDynamicSymbol` for looking up a dyld binding for an address
Note: each of these names could be improved. Some alternative terms: `lookup` instead of `get`, `Binding` or `BindingName` instead of `DynamicSymbol`. Maybe even another term instead of "resolve". Suggestions welcome!
Currently, `swift-reflection-dump` supports `getDynamicSymbol` but not `getSymbol`. For lldb it's the reverse, `getSymbol` is supported but `getDynamicSymbol` needs to be implemented.
For everything but lldb, this change is NFC. For lldb it fixes a bug where `LLDBMemoryReader` returns regular symbols where we should instead be returning dynamic symbols.
This commit adds new entry-points to `libSwiftScan` that operate on the new BinaryScanningTool, which reads out Swift type information from object files, starting with a query of all protocol conformances.
Previously, the code assumed that such an indirect target will always point to an external symbol pointer, but it can also be an absolute pointer to an in-image protocol descriptor.
