We remove the existing `swift_reflection_iterateAsyncTaskAllocations` API that attempts to provide all necessary information about a tasks's allocations starting from the task. Instead, we split it into two pieces: `swift_reflection_asyncTaskSlabPointer` to get the first slab for a task, and `+swift_reflection_asyncTaskSlabAllocations` to get the allocations in a slab, and a pointer to the next slab.
We also add a dummy metadata pointer to the beginning of each slab. This allows tools to identify slab allocations on the heap without needing to locate every single async task object. They can then use `swift_reflection_asyncTaskSlabAllocations` on such allocations to find out about the contents.
rdar://82549631
On Windows, std::max_align_t is only 8-byte aligned, but Swift assumes 16-byte alignment. MaximumAlignment is our notion of the maximum alignment of a type, so use that instead.
We remove the existing `swift_reflection_iterateAsyncTaskAllocations` API that attempts to provide all necessary information about a tasks's allocations starting from the task. Instead, we split it into two pieces: `swift_reflection_asyncTaskSlabPointer` to get the first slab for a task, and `+swift_reflection_asyncTaskSlabAllocations` to get the allocations in a slab, and a pointer to the next slab.
We also add a dummy metadata pointer to the beginning of each slab. This allows tools to identify slab allocations on the heap without needing to locate every single async task object. They can then use `swift_reflection_asyncTaskSlabAllocations` on such allocations to find out about the contents.
rdar://82549631
Fix the declaration of AsyncTask and add a test for iterateAsyncTaskAllocations. Reflection's declaration of AsyncTask had fallen out of sync with the real thing. The test that was supposed to catch this was never actually committed, oops.
Add a swift_reflection_libraryVersion variable to Remote Mirror to indicate the presence of this fix. In the future, the value can be incremented to signal the presence of other changes that can't otherwise be detected.
rdar://80035307
Implement a version of addImage that takes in a closure responsible
for finding the sections of interest. This allows for the registration
of metadata even in situations where the object file is not complete
(for example, when generated by the JIT).
This will allow the heap tool to work out which binary a dynamically allocated
class comes from, by looking up its nominal type descriptor address and then
seeing which binary contains that.
Fixes rdar://65742351.
Implement a version of projectExistential tailored for LLDB. There are 2
differences when projecting existentials for LLDB:
1 - When it comes to existentials, LLDB stores the address of the error
pointer, which must be dereferenced.
2 - When the existential wraps a class type, LLDB expects the address
returned is the class instance itself and not the address of the
reference.
This patch also adapts the swift reflection test machinery to test
projectExistentialAndUnwrapClass as well. This is done by exposing
the new functionality from swift reflection test. It is tested in
existentials.swift, and ensures that the typeref information is
exactly the same as what is expected from projectExistential,
except the out address.
(cherry picked from commit 55e971e06750c3ba29722d558cc5400298f6bdaf)
This changes how ReflectionContext reads machO reflection sections by reading them individually instead of as one big memory block spanning from the first to the last section (and including whatever else is in between). This change will enable an optimization on LLDB's side where, if we're reading read-only data, we read from the file-cache instead of the child process, which should speed up debugging when working with remote processes.
We found crashes deep in TypeRefBuilder that could traced back to a likely
nullptr RemoteRef<> section address. It is very plausible that this is
connected to a failed MemoryReader::getBytes() call, which can fail but
isn't checked.
This patch adds missing error checks to every call to readBytes().
rdar://74445486
(cherry picked from commit 714cefbba4)
swift::reflection::TypeInfo for (Clang-)imported non-Objective-C types. This is
needed to reflect on the size mixed Swift / Clang types, when no type metadata
is available for the C types.
This is a necessary ingredient for the TypeRef-based Swift context in
LLDB. Because we do not have reflection metadata for pure C types in Swift,
reflection cannot compute TypeInfo for NominalTypeRefs for those types. By
providing this callback, LLDB can supply this information for DWARF, and
reflection can compute TypeInfos for mixed Swift/C types.
to use it.
ConcurrentReadableHashMap is lock-free for readers, with writers using a lock to
ensure mutual exclusion amongst each other. The intent is to eventually replace
all uses ConcurrentMap with ConcurrentReadableHashMap.
ConcurrentReadableHashMap provides for relatively quick lookups by using a hash
table. Rearders perform an atomic increment/decrement in order to inform writers
that there are active readers. The design attempts to minimize wasted memory by
storing the actual elements out-of-line, and having the table store indices into
a separate array of elements.
The protocol conformance cache now uses ConcurrentReadableHashMap, which
provides faster lookups and less memory use than the previous ConcurrentMap
implementation. The previous implementation caches
ProtocolConformanceDescriptors and extracts the WitnessTable after the cache
lookup. The new implementation directly caches the WitnessTable, removing an
extra step (potentially a quite slow one) from the fast path.
The previous implementation used a generational scheme to detect when negative
cache entries became obsolete due to new dynamic libraries being loaded, and
update them in place. The new implementation just clears the entire cache when
libraries are loaded, greatly simplifying the code and saving the memory needed
to track the current generation in each negative cache entry. This means we need
to re-cache all requested conformances after loading a dynamic library, but
loading libraries at runtime is rare and slow anyway.
rdar://problem/67268325
This code rearchitects and simplifies the projectEnumValue support by
introducing a new `TypeInfo` subclass for each kind of enum, including trivial,
no-payload, single-payload, and three different classes for multi-payload enums:
* "UnsupportedEnum" that we don't understand. This returns "don't know" answers for all requests in cases where the runtime lacks enough information to accurately handle a particular enum.
* MP Enums that only use a separate tag value. This includes generic enums and other dynamic layouts, as well as enums whose payloads have no spare bits.
* MP Enums that use spare bits, possibly in addition to a separate tag. This logic can only be used, of course, if we can in fact compute a spare bit mask that agrees with the compiler.
The final challenge is to choose one of the above three handlings for every MPE. Currently, we do not have an accurate source of information for the spare bit mask, so we never choose the third option above. We use the second option for dynamic MPE layouts (including generics) and the first for everything else.
TODO: Once we can arrange for the compiler to expose spare bit mask data, we'll be able to use that to drive more MPE cases.
ownsAddress was a simple range check on images, but that won't find Metadatas that get allocated on the heap. If an address isn't found, try reading it as a Metadata and doing a range check on the type context descriptor too.
rdar://problem/60981575
This indirectly hardens the `swift_reflection_infoForTypeRef` API
against being invoked with a null TypeRef pointer. The API already
handles a nullptr being returned from `TypeConverter::getTypeInfo`
by converting it into a standard "UNKNOWN" type info descriptor.
Resolves rdar://60633988
* First part of multi-payload enum support
This handles multi-payload enums with fixed
layouts that don't use spare payload bits.
It includes XI calculations that allow us to
handle single-payload enums where the payload
ultimately includes a multi-payload enum
(For example, on 32-bit platforms, String uses
a multi-payload enum, so this now supports single-payload
enums carrying Strings.)
Teach RemoteMirror how to project enum values
This adds two new functions to the SwiftRemoteMirror
facility that support inspecting enum values.
Currently, these support non-payload enums and
single-payload enums, including nested enums and
payloads with struct, tuple, and reference payloads.
In particular, it handles nested `Optional` types.
TODO: Multi-payload enums use different strategies for
encoding the cases that aren't yet supported by this
code.
Note: This relies on information from dataLayoutQuery
to correctly decode invalid pointer values that are used
to encode enums. Existing clients will need to augment
their DLQ functions before using these new APIs.
Resolves rdar://59961527
```
/// Projects the value of an enum.
///
/// Takes the address and typeref for an enum and determines the
/// index of the currently-selected case within the enum.
///
/// Returns true iff the enum case could be successfully determined.
/// In particular, note that this code may fail for valid in-memory data
/// if the compiler is using a strategy we do not yet understand.
SWIFT_REMOTE_MIRROR_LINKAGE
int swift_reflection_projectEnumValue(SwiftReflectionContextRef ContextRef,
swift_addr_t EnumAddress,
swift_typeref_t EnumTypeRef,
uint64_t *CaseIndex);
/// Finds information about a particular enum case.
///
/// Given an enum typeref and index of a case, returns:
/// * Typeref of the associated payload or zero if there is no payload
/// * Name of the case if known.
///
/// The Name points to a freshly-allocated C string on the heap. You
/// are responsible for freeing the string (via `free()`) when you are finished.
SWIFT_REMOTE_MIRROR_LINKAGE
int swift_reflection_getEnumCaseTypeRef(SwiftReflectionContextRef ContextRef,
swift_typeref_t EnumTypeRef,
unsigned CaseIndex,
char **CaseName,
swift_typeref_t *PayloadTypeRef);
```
Co-authored-by: Mike Ash <mikeash@apple.com>
As the base of the "remote" address space ObjectMemoryReader presents for an image, use the
image's own preferred VM address mappings. If there are multiple images loaded, differentiate
them by using the top 16 bits of the remote address space as an index into the array of images.
This should make it so that absolute pointers in the file Just Work without sliding in most
cases; we'd only need to mix in the image index in order to have a value that is also a valid
remote address.
Pointer data in some remote reflection targets may required relocation, or may not be
fully resolvable, such as when we're dumping info from a single image on disk that
references other dynamic libraries. Add a `RemoteAbsolutePointer` type that can hold a
symbol, offset, or combination of both, and add APIs to `MemoryReader` and `MetadataReader`
for reading pointers that can get unresolved relocation info from an image, or apply
relocations to pointer information. MetadataReader can use the symbol name information to
fill in demanglings of symbolic-reference-bearing mangled names by using the information
from the symbol name to fill in the name even though the context descriptors are not
available.
For now, this is NFC (MemoryReader::resolvePointer just forwards the pointer data), but
lays the groundwork for implementation of relocation in ObjectMemoryReader.
