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[stdlib] Fix cc mismatch violation on swift_isClassType #39119

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Merged
merged 1 commit into from
Aug 18, 2022
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[stdlib] Fix cc mismatch violation on swift_isClassType #39119

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7 changes: 7 additions & 0 deletions stdlib/public/SwiftShims/RuntimeShims.h
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Expand Up @@ -20,6 +20,7 @@

#include "SwiftStddef.h"
#include "SwiftStdint.h"
#include "SwiftStdbool.h"
#include "Visibility.h"

#ifdef __cplusplus
Expand Down Expand Up @@ -61,6 +62,12 @@ 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 ==
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7 changes: 5 additions & 2 deletions stdlib/public/core/ReflectionMirror.swift
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Expand Up @@ -12,8 +12,11 @@

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))
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I don't understand this. I guess I should look at the implementation. But this deserves a comment. You are passing the metatype structure as a pointer?

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According to here, a thick metatype is represented with a metadata pointer.
https://github.com/apple/swift/blob/dd32711a5f5c5bd28a6401fc3ede1a0bf344b49e/lib/IRGen/GenType.cpp#L2464-L2466

So the unsafeBitCast is a safe operation. But I agree this is not clear to everyone, so it should be described in comments.

}

@_silgen_name("swift_getMetadataKind")
internal func _metadataKind(_: Any.Type) -> UInt
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