[Reflection] Implement an SPI to iterate types who conform to some protocol

stdlib/public/runtime/ImageInspection.h → include/swift/Runtime/ImageInspection.h

@@ -22,6 +22,7 @@
 #define SWIFT_RUNTIME_IMAGEINSPECTION_H
 
 #include "swift/Runtime/Config.h"
+#include "swift/Runtime/SymbolInfo.h"
 
 #include <cstdint>
 #include <cstddef>
@@ -35,8 +36,6 @@
 #include <Windows.h>
 #endif
 
-#include "SymbolInfo.h"
-
 namespace swift {
 
 /// Load the metadata from the image necessary to find protocols by name.

include/swift/Runtime/ImageInspectionMachO.h

@@ -0,0 +1,142 @@
+//===--- ImageInspectionMachO.cpp - Mach-O image inspection ---------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+///
+/// This file includes routines that interact with dyld on Mach-O-based
+/// platforms to extract runtime metadata embedded in images generated by the
+/// Swift compiler.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_RUNTIME_IMAGEINSPECTIONMACHO_H
+#define SWIFT_RUNTIME_IMAGEINSPECTIONMACHO_H
+
+#if defined(__APPLE__) && defined(__MACH__) &&                                 \
+    !defined(SWIFT_RUNTIME_STATIC_IMAGE_INSPECTION)
+
+#include "swift/Runtime/Config.h"
+#include "swift/Runtime/ImageInspection.h"
+#include "swift/Runtime/ImageInspectionCommon.h"
+#include <mach-o/dyld.h>
+#include <mach-o/getsect.h>
+#include <objc/runtime.h>
+#include <assert.h>
+#include <dlfcn.h>
+
+namespace {
+
+constexpr const char ProtocolsSection[] = MachOProtocolsSection;
+constexpr const char ProtocolConformancesSection[] =
+    MachOProtocolConformancesSection;
+constexpr const char TypeMetadataRecordSection[] =
+    MachOTypeMetadataRecordSection;
+constexpr const char DynamicReplacementSection[] =
+    MachODynamicReplacementSection;
+constexpr const char DynamicReplacementSomeSection[] =
+    MachODynamicReplacementSomeSection;
+constexpr const char AccessibleFunctionsSection[] =
+    MachOAccessibleFunctionsSection;
+constexpr const char TextSegment[] = MachOTextSegment;
+
+#if __POINTER_WIDTH__ == 64
+using mach_header_platform = mach_header_64;
+#else
+using mach_header_platform = mach_header;
+#endif
+
+template <const char *SEGMENT_NAME, const char *SECTION_NAME,
+         void CONSUME_BLOCK(const void *baseAddress,
+                            const void *start, uintptr_t size)>
+void addImageCallback(const mach_header *mh) {
+#if __POINTER_WIDTH__ == 64
+  assert(mh->magic == MH_MAGIC_64 && "loaded non-64-bit image?!");
+#endif
+
+  // Look for a __swift5_proto section.
+  unsigned long size;
+  const uint8_t *section =
+  getsectiondata(reinterpret_cast<const mach_header_platform *>(mh),
+                 SEGMENT_NAME, SECTION_NAME,
+                 &size);
+
+  if (!section)
+    return;
+
+  CONSUME_BLOCK(mh, section, size);
+}
+template <const char *SEGMENT_NAME, const char *SECTION_NAME,
+         void CONSUME_BLOCK(const void *baseAddress,
+                            const void *start, uintptr_t size)>
+void addImageCallback(const mach_header *mh, intptr_t vmaddr_slide) {
+  addImageCallback<SEGMENT_NAME, SECTION_NAME, CONSUME_BLOCK>(mh);
+}
+
+template <const char *SEGMENT_NAME, const char *SECTION_NAME,
+          const char *SEGMENT_NAME2, const char *SECTION_NAME2,
+          void CONSUME_BLOCK(const void *baseAddress,
+                             const void *start, uintptr_t size,
+                             const void *start2, uintptr_t size2)>
+void addImageCallback2Sections(const mach_header *mh) {
+#if __POINTER_WIDTH__ == 64
+  assert(mh->magic == MH_MAGIC_64 && "loaded non-64-bit image?!");
+#endif
+
+  // Look for a section.
+  unsigned long size;
+  const uint8_t *section =
+  getsectiondata(reinterpret_cast<const mach_header_platform *>(mh),
+                 SEGMENT_NAME, SECTION_NAME,
+                 &size);
+
+  if (!section)
+    return;
+
+  // Look for another section.
+  unsigned long size2;
+  const uint8_t *section2 =
+  getsectiondata(reinterpret_cast<const mach_header_platform *>(mh),
+                 SEGMENT_NAME2, SECTION_NAME2,
+                 &size2);
+  if (!section2)
+    size2 = 0;
+
+  CONSUME_BLOCK(mh, section, size, section2, size2);
+}
+template <const char *SEGMENT_NAME, const char *SECTION_NAME,
+          const char *SEGMENT_NAME2, const char *SECTION_NAME2,
+          void CONSUME_BLOCK(const void *baseAddress,
+                             const void *start, uintptr_t size,
+                             const void *start2, uintptr_t size2)>
+void addImageCallback2Sections(const mach_header *mh, intptr_t vmaddr_slide) {
+  addImageCallback2Sections<SEGMENT_NAME, SECTION_NAME,
+                            SEGMENT_NAME2, SECTION_NAME2,
+                            CONSUME_BLOCK>(mh);
+}
+
+} // end anonymous namespace
+
+#if OBJC_ADDLOADIMAGEFUNC_DEFINED && SWIFT_OBJC_INTEROP
+#define REGISTER_FUNC(...)                                               \
+  if (__builtin_available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)) { \
+    objc_addLoadImageFunc(__VA_ARGS__);                                  \
+  } else {                                                               \
+    _dyld_register_func_for_add_image(__VA_ARGS__);                      \
+  }
+#else
+#define REGISTER_FUNC(...) _dyld_register_func_for_add_image(__VA_ARGS__)
+#endif
+
+#endif // defined(__APPLE__) && defined(__MACH__) &&
+       // !defined(SWIFT_RUNTIME_STATIC_IMAGE_INSPECTION)
+
+#endif 

stdlib/public/CompatibilityOverride/CompatibilityOverride.cpp

@@ -18,7 +18,7 @@
 
 #ifdef SWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT
 
-#include "../runtime/ImageInspection.h"
+#include "swift/Runtime/ImageInspection.h"
 #include "swift/Runtime/Once.h"
 #include <assert.h>
 #include <atomic>

stdlib/public/Reflection/Sources/Reflection/CMakeLists.txt

@@ -17,6 +17,7 @@ list(APPEND SWIFT_REFLECTION_SWIFT_FLAGS
 
 add_swift_target_library(swiftReflection ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
   Case.swift
+  Conformances.swift
   Field.swift
   GenericArguments.swift
   KeyPath.swift

stdlib/public/Reflection/Sources/Reflection/Conformances.swift

@@ -0,0 +1,66 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+//
+//===----------------------------------------------------------------------===//
+
+#if os(macOS) || os(iOS) || os(tvOS) || os(watchOS)
+
+import Swift
+import _Runtime
+
+@available(SwiftStdlib 5.9, *)
+@_silgen_name("_swift_reflection_withConformanceCache")
+func _withConformanceCache(
+  _ proto: ProtocolDescriptor,
+  _ context: UnsafeMutableRawPointer,
+  _ callback: @convention(c) (
+    /* Array of types */ UnsafePointer<UnsafeRawPointer>,
+    /* Number of types */ Int,
+    /* Context we just passed */ UnsafeMutableRawPointer
+  ) -> ()
+)
+
+@available(SwiftStdlib 5.9, *)
+@_spi(Reflection)
+public func _typesThatConform(to type: Any.Type) -> [Any.Type]? {
+  let meta = Metadata(type)
+
+  guard meta.kind == .existential else {
+    return nil
+  }
+
+  let existential = meta.existential
+
+  let protos = existential.protocols
+
+  guard protos.count == 1 else {
+    return nil
+  }
+
+  let proto = protos[0]
+
+  var result: [Any.Type] = []
+
+  withUnsafeMutablePointer(to: &result) {
+    _withConformanceCache(proto, UnsafeMutableRawPointer($0)) {
+      let buffer = UnsafeBufferPointer<Any.Type>(
+        start: UnsafePointer<Any.Type>($0._rawValue),
+        count: $1
+      )
+
+      let arrayPtr = $2.assumingMemoryBound(to: [Any.Type].self)
+
+      arrayPtr.pointee = Array(buffer)
+    }
+  }
+
+  return result
+}
+
+#endif

stdlib/public/Reflection/Sources/_Runtime/CMakeLists.txt

@@ -64,6 +64,7 @@ add_swift_target_library(swift_Runtime ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_ST
   Utils/RelativePointer.swift
   Utils/TypeCache.swift
 
+  Caches.cpp
   ConformanceDescriptor.swift
   ExistentialContainer.swift
   Functions.swift