Merge pull request #39119 from kateinoigakukun/katei/fix-internal-cc-mismatch

[stdlib] Fix cc mismatch violation on swift_isClassType

Author: jckarter

stdlib/public/SwiftShims/RuntimeShims.h

@@ -21,6 +21,7 @@
 #include "SwiftStdbool.h"
 #include "SwiftStddef.h"
 #include "SwiftStdint.h"
+#include "SwiftStdbool.h"
 #include "Visibility.h"
 
 #ifdef __cplusplus
@@ -62,6 +63,12 @@ int _swift_stdlib_putc_stderr(int C);
 SWIFT_RUNTIME_STDLIB_API
 __swift_size_t _swift_stdlib_getHardwareConcurrency(void);
 
+#ifdef __swift__
+/// Called by ReflectionMirror in stdlib through C-calling-convention
+SWIFT_RUNTIME_STDLIB_API
+__swift_bool swift_isClassType(const void *type);
+#endif
+
 /// Manually allocated memory is at least 16-byte aligned in Swift.
 ///
 /// When swift_slowAlloc is called with "default" alignment (alignMask ==

stdlib/public/core/ReflectionMirror.swift

@@ -14,8 +14,11 @@
 
 import SwiftShims
 
-@_silgen_name("swift_isClassType")
-internal func _isClassType(_: Any.Type) -> Bool
+internal func _isClassType(_ type: Any.Type) -> Bool {
+  // a thick metatype is represented with a pointer metadata structure,
+  // so this unsafeBitCast is a safe operation here.
+  return swift_isClassType(unsafeBitCast(type, to: UnsafeRawPointer.self))
+}
 
 @_silgen_name("swift_getMetadataKind")
 internal func _metadataKind(_: Any.Type) -> UInt