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//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2023–2025 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 Swift project authors
//
#include "Discovery.h"
#if !defined(SWT_NO_LEGACY_TEST_DISCOVERY)
#include <cstdint>
#include <cstring>
#include <type_traits>
#pragma mark - Swift ABI
#if defined(__PTRAUTH_INTRINSICS__)
#include <ptrauth.h>
#define SWT_PTRAUTH_SWIFT_TYPE_DESCRIPTOR __ptrauth(ptrauth_key_process_independent_data, 1, 0xae86)
#else
#define SWT_PTRAUTH_SWIFT_TYPE_DESCRIPTOR
#endif
/// A type representing a pointer relative to itself.
///
/// This type is derived from `RelativeDirectPointerIntPair` in the Swift
/// repository.
template <typename T, int32_t maskValue = 0>
struct SWTRelativePointer {
private:
int32_t _offset;
public:
SWTRelativePointer(const SWTRelativePointer&) = delete;
SWTRelativePointer(const SWTRelativePointer&&) = delete;
SWTRelativePointer& operator =(const SWTRelativePointer&) = delete;
SWTRelativePointer& operator =(const SWTRelativePointer&&) = delete;
int32_t getRawValue(void) const {
return _offset;
}
const T *_Nullable get(void) const& {
int32_t maskedOffset = getRawValue() & ~maskValue;
if (maskedOffset == 0) {
return nullptr;
}
auto offset = static_cast<uintptr_t>(static_cast<intptr_t>(maskedOffset));
auto result = reinterpret_cast<void *>(reinterpret_cast<uintptr_t>(this) + offset);
#if defined(__PTRAUTH_INTRINSICS__)
if (std::is_function_v<T> && result) {
result = ptrauth_strip(result, ptrauth_key_function_pointer);
result = ptrauth_sign_unauthenticated(result, ptrauth_key_function_pointer, 0);
}
#endif
return reinterpret_cast<const T *>(result);
}
};
/// A type representing a 32-bit absolute function pointer, usually used on platforms
/// where relative function pointers are not supported.
///
/// This type is derived from `AbsoluteFunctionPointer` in the Swift repository.
template <typename T>
struct SWTAbsoluteFunctionPointer {
private:
T *_pointer;
static_assert(sizeof(T *) == sizeof(int32_t), "Function pointer must be 32-bit when using compact absolute pointer");
public:
const T *_Nullable get(void) const & {
return _pointer;
}
};
/// A type representing a pointer relative to itself with low bits reserved for
/// use as flags.
///
/// This type is derived from `RelativeDirectPointerIntPair` in the Swift
/// repository.
template <typename T, typename I, int32_t maskValue = (alignof(int32_t) - 1)>
struct SWTRelativePointerIntPair: public SWTRelativePointer<T, maskValue> {
I getInt() const & {
return I(this->getRawValue() & maskValue);
}
};
template <typename T>
#if defined(__wasm32__)
using SWTCompactFunctionPointer = SWTAbsoluteFunctionPointer<T>;
#else
using SWTCompactFunctionPointer = SWTRelativePointer<T>;
#endif
/// A type representing a metatype as constructed during compilation of a Swift
/// module.
///
/// This type is derived from `TargetTypeContextDescriptor` in the Swift
/// repository.
struct SWTTypeContextDescriptor {
private:
uint32_t _flags;
SWTRelativePointer<void> _parent;
SWTRelativePointer<char> _name;
struct MetadataAccessResponse {
void *value;
size_t state;
};
using MetadataAccessFunction = __attribute__((swiftcall)) MetadataAccessResponse(size_t);
SWTCompactFunctionPointer<MetadataAccessFunction> _metadataAccessFunction;
public:
const char *_Nullable getName(void) const& {
return _name.get();
}
void *_Nullable getMetadata(void) const& {
if (auto fp = _metadataAccessFunction.get()) {
return (* fp)(0xFF).value;
}
return nullptr;
}
bool isGeneric(void) const& {
return (_flags & 0x80u) != 0;
}
};
/// A type representing a relative pointer to a type descriptor.
///
/// This type is derived from `TargetTypeMetadataRecord` in the Swift
/// repository.
struct SWTTypeMetadataRecord {
private:
SWTRelativePointerIntPair<void, unsigned int> _pointer;
public:
const SWTTypeContextDescriptor *_Nullable getContextDescriptor(void) const {
switch (_pointer.getInt()) {
case 0: // Direct pointer.
return reinterpret_cast<const SWTTypeContextDescriptor *>(_pointer.get());
case 1: // Indirect pointer (pointer to a pointer.)
// The inner pointer is signed when pointer authentication
// instructions are available.
if (auto contextDescriptor = reinterpret_cast<SWTTypeContextDescriptor *const SWT_PTRAUTH_SWIFT_TYPE_DESCRIPTOR *>(_pointer.get())) {
return *contextDescriptor;
}
[[fallthrough]];
default: // Unsupported or invalid.
return nullptr;
}
}
};
#pragma mark - Legacy test discovery
const size_t SWTTypeMetadataRecordByteCount = sizeof(SWTTypeMetadataRecord);
const void *swt_getTypeFromTypeMetadataRecord(const void *recordAddress, const char *nameSubstring) {
auto record = reinterpret_cast<const SWTTypeMetadataRecord *>(recordAddress);
auto contextDescriptor = record->getContextDescriptor();
if (!contextDescriptor) {
// This type metadata record is invalid (or we don't understand how to
// get its context descriptor), so skip it.
return nullptr;
} else if (contextDescriptor->isGeneric()) {
// Generic types cannot be fully instantiated without generic
// parameters, which is not something we can know abstractly.
return nullptr;
}
// Check that the type's name passes. This will be more expensive than the
// checks above, but should be cheaper than realizing the metadata.
const char *typeName = contextDescriptor->getName();
bool nameOK = typeName && nullptr != std::strstr(typeName, nameSubstring);
if (!nameOK) {
return nullptr;
}
if (void *typeMetadata = contextDescriptor->getMetadata()) {
return typeMetadata;
}
return nullptr;
}
#endif
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