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kubamracekkubamracek
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Merge pull request #70944 from kubamracek/volatile
Add experimental _Volatile module providing low-level primitives for MMIO
2 parents 512ac6c + 62f1e3b commit 70afeef

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+407
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‎include/swift/AST/DiagnosticsSema.def‎

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@@ -925,6 +925,9 @@ ERROR(cannot_import_embedded_module,none,
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ERROR(cannot_import_non_embedded_module,none,
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"module %0 cannot be imported in embedded Swift mode",
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(Identifier))
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ERROR(volatile_is_experimental,none,
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"importing _Volatile module requires '-enable-experimental-feature Volatile'", ())
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ERROR(need_cxx_interop_to_import_module,none,
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"module %0 was built with C++ interoperability enabled, but "
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"current compilation does not enable C++ interoperability",

‎include/swift/Basic/Features.def‎

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@@ -317,6 +317,9 @@ EXPERIMENTAL_FEATURE(RawLayout, true)
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/// Enables the "embedded" swift mode (no runtime).
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EXPERIMENTAL_FEATURE(Embedded, true)
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/// Enables importing the Volatile module
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EXPERIMENTAL_FEATURE(Volatile, true)
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/// Enables noncopyable generics
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SUPPRESSIBLE_EXPERIMENTAL_FEATURE(NoncopyableGenerics, true)
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‎lib/AST/FeatureSet.cpp‎

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@@ -505,6 +505,7 @@ static bool usesFeatureRawLayout(Decl *decl) {
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}
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UNINTERESTING_FEATURE(Embedded)
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UNINTERESTING_FEATURE(Volatile)
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UNINTERESTING_FEATURE(SuppressedAssociatedTypes)
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static bool usesFeatureNoncopyableGenerics(Decl *decl) {

‎lib/Sema/ImportResolution.cpp‎

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@@ -397,6 +397,15 @@ ImportResolver::getModule(ImportPath::Module modulePath) {
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}
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}
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// Only allow importing "Volatile" with Feature::Volatile or Feature::Embedded
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if (!ctx.LangOpts.hasFeature(Feature::Volatile) &&
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!ctx.LangOpts.hasFeature(Feature::Embedded)) {
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if (ctx.getRealModuleName(moduleID.Item).str() == "_Volatile") {
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ctx.Diags.diagnose(SourceLoc(), diag::volatile_is_experimental);
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return nullptr;
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}
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}
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// If the imported module name is the same as the current module,
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// skip the Swift module loader and use the Clang module loader instead.
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// This allows a Swift module to extend a Clang module of the same name.

‎stdlib/public/CMakeLists.txt‎

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@@ -280,6 +280,8 @@ if(SWIFT_BUILD_STDLIB AND NOT SWIFT_STDLIB_BUILD_ONLY_CORE_MODULES)
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if(SWIFT_ENABLE_SYNCHRONIZATION)
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add_subdirectory(Synchronization)
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endif()
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add_subdirectory(Volatile)
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endif()
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if(SWIFT_BUILD_REMOTE_MIRROR)

‎stdlib/public/Volatile/CMakeLists.txt‎

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@@ -0,0 +1,56 @@
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#===--- CMakeLists.txt ---------------------------------------------------===#
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#
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# This source file is part of the Swift.org open source project
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#
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# Copyright (c) 2019 - 2022 Apple Inc. and the Swift project authors
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# Licensed under Apache License v2.0 with Runtime Library Exception
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#
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# See https://swift.org/LICENSE.txt for license information
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# See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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#
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#===----------------------------------------------------------------------===#
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add_swift_target_library(swift_Volatile ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
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Volatile.swift
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SWIFT_COMPILE_FLAGS
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${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
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-parse-stdlib
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LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
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INSTALL_IN_COMPONENT stdlib
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)
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if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
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add_custom_target(embedded-volatile ALL)
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foreach(entry ${EMBEDDED_STDLIB_TARGET_TRIPLES})
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string(REGEX REPLACE "[ \t]+" ";" list "${entry}")
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list(GET list 0 arch)
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list(GET list 1 mod)
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list(GET list 2 triple)
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set(SWIFT_SDK_embedded_ARCH_${arch}_MODULE "${mod}")
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set(SWIFT_SDK_embedded_LIB_SUBDIR "embedded")
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set(SWIFT_SDK_embedded_ARCH_${arch}_TRIPLE "${triple}")
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add_swift_target_library_single(
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embedded-volatile-${mod}
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swift_Volatile
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ONLY_SWIFTMODULE
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IS_SDK_OVERLAY IS_FRAGILE
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Volatile.swift
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SWIFT_COMPILE_FLAGS
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-Xcc -D__MACH__ -Xcc -D__APPLE__ -Xcc -ffreestanding -enable-experimental-feature Embedded
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-parse-stdlib
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C_COMPILE_FLAGS
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-D__MACH__ -D__APPLE__ -ffreestanding
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MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
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SDK "embedded"
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ARCHITECTURE "${arch}"
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DEPENDS embedded-stdlib-${mod}
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INSTALL_IN_COMPONENT stdlib
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)
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add_dependencies(embedded-volatile embedded-volatile-${mod})
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endforeach()
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endif()

‎stdlib/public/Volatile/Volatile.swift‎

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//===----------------------------------------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2020 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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import Swift
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/// A pointer for accessing "volatile" memory, e.g. memory-mapped I/O registers.
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///
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/// Do not use for inter-thread synchronization. This is only meaningful for
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/// low-level operations on special memory addresses performed from OS kernels,
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/// embedded firmware, and similar environments.
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///
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/// The semantics of volatile load and volatile store operations match the LLVM
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/// volatile semantics. Notably, a volatile operation cannot be added, removed,
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/// or reordered with other volatile operations by the compiler. They may be
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/// reordered with non-volatile operations. For details, see
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/// <https://llvm.org/docs/LangRef.html#volatile-memory-accesses>.
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@frozen
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public struct VolatileMappedRegister<Pointee> {
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@usableFromInline
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let _rawPointer: Builtin.RawPointer
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@_transparent
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public init(unsafeBitPattern: UInt) {
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self._rawPointer = Builtin.inttoptr_Word(unsafeBitPattern._builtinWordValue)
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}
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}
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extension VolatileMappedRegister where Pointee == UInt8 {
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/// Perform an 8-bit volatile load operation from the target pointer.
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///
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/// Do not use for inter-thread synchronization.
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@_transparent
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public func load() -> Pointee {
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UInt8(Builtin.atomicload_monotonic_volatile_Int8(_rawPointer))
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}
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/// Perform an 8-bit volatile store operation on the target pointer.
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///
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/// Do not use for inter-thread synchronization.
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@_transparent
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public func store(_ value: Pointee) {
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Builtin.atomicstore_monotonic_volatile_Int8(_rawPointer, value._value)
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}
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}
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extension VolatileMappedRegister where Pointee == UInt16 {
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/// Perform a 16-bit volatile load operation from the target pointer.
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///
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/// Do not use for inter-thread synchronization.
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@_transparent
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public func load() -> Pointee {
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UInt16(Builtin.atomicload_monotonic_volatile_Int16(_rawPointer))
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}
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/// Perform a 16-bit volatile store operation on the target pointer.
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///
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/// Do not use for inter-thread synchronization.
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@_transparent
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public func store(_ value: Pointee) {
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Builtin.atomicstore_monotonic_volatile_Int16(_rawPointer, value._value)
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}
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}
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extension VolatileMappedRegister where Pointee == UInt32 {
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/// Perform a 32-bit volatile load operation from the target pointer.
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///
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/// Do not use for inter-thread synchronization.
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@_transparent
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public func load() -> Pointee {
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UInt32(Builtin.atomicload_monotonic_volatile_Int32(_rawPointer))
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}
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/// Perform a 32-bit volatile store operation on the target pointer.
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///
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/// Do not use for inter-thread synchronization.
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@_transparent
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public func store(_ value: Pointee) {
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Builtin.atomicstore_monotonic_volatile_Int32(_rawPointer, value._value)
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}
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}
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extension VolatileMappedRegister where Pointee == UInt64 {
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/// Perform a 64-bit volatile load operation from the target pointer.
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///
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/// Do not use for inter-thread synchronization.
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@_transparent
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public func load() -> Pointee {
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UInt64(Builtin.atomicload_monotonic_volatile_Int64(_rawPointer))
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}
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/// Perform a 64-bit volatile store operation on the target pointer.
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///
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/// Do not use for inter-thread synchronization.
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@_transparent
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public func store(_ value: Pointee) {
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Builtin.atomicstore_monotonic_volatile_Int64(_rawPointer, value._value)
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}
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}

‎test/Volatile/volatile-exec.swift‎

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// RUN: %target-run-simple-swift(-parse-as-library -enable-experimental-feature Volatile) | %FileCheck %s
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// REQUIRES: executable_test
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import _Volatile
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@main
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struct Main {
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static func main() {
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var byte: UInt8 = 42
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withUnsafePointer(to: &byte) { p in
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let volatilePointer = VolatileMappedRegister<UInt8>(unsafeBitPattern: UInt(bitPattern: p))
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print("byte = \(volatilePointer.load())")
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// CHECK: byte = 42
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volatilePointer.store(77)
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}
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print("byte = \(byte)")
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// CHECK: byte = 77
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var heapPointer = UnsafeMutablePointer<UInt8>.allocate(capacity: 16) // uninitialized content
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for i in 0 ..< 16 {
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let pointerWithOffset = heapPointer.advanced(by: i)
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let volatilePointer = VolatileMappedRegister<UInt8>(unsafeBitPattern: UInt(bitPattern: pointerWithOffset))
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volatilePointer.store(UInt8(0x61 + i))
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}
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heapPointer[15] = 0
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print(String(cString: heapPointer))
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// CHECK: abcdefghijklmno
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}
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}

‎test/Volatile/volatile-feature-flag.swift‎

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// RUN: %empty-directory(%t)
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// RUN: not %target-swift-emit-ir %s -module-name main -parse-as-library 2>&1 | %FileCheck %s
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// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Volatile
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import _Volatile
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// CHECK: importing _Volatile module requires '-enable-experimental-feature Volatile'

‎test/Volatile/volatile-ir.swift‎

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// RUN: %empty-directory(%t)
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// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Volatile -Onone | %FileCheck %s
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// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Volatile -O | %FileCheck %s
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// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Volatile -Osize | %FileCheck %s
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import _Volatile
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public func test_uint8() -> UInt8 {
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let p = VolatileMappedRegister<UInt8>(unsafeBitPattern: 0xf000baa9)
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p.store(42)
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return p.load()
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}
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// CHECK: define {{.*}}i8 @"$s4main10test_uint8s5UInt8VyF"()
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// CHECK: store atomic volatile i8 42, ptr {{.*}} monotonic, align 1
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// CHECK: [[RET:%.*]] = load atomic volatile i8, ptr {{.*}} monotonic, align 1
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// CHECK: ret i8 [[RET]]
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// CHECK: }
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public func test_uint16() -> UInt16 {
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let p = VolatileMappedRegister<UInt16>(unsafeBitPattern: 0xf000baaa)
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p.store(42)
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return p.load()
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}
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// CHECK: define {{.*}}i16 @"$s4main11test_uint16s6UInt16VyF"()
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// CHECK: store atomic volatile i16 42, ptr {{.*}} monotonic, align 2
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// CHECK: [[RET:%.*]] = load atomic volatile i16, ptr {{.*}} monotonic, align 2
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// CHECK: ret i16 [[RET]]
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// CHECK: }
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public func test_uint32() -> UInt32 {
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let p = VolatileMappedRegister<UInt32>(unsafeBitPattern: 0xf000baaa)
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p.store(42)
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return p.load()
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}
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// CHECK: define {{.*}}i32 @"$s4main11test_uint32s6UInt32VyF"()
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// CHECK: store atomic volatile i32 42, ptr {{.*}} monotonic, align 4
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// CHECK: [[RET:%.*]] = load atomic volatile i32, ptr {{.*}} monotonic, align 4
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// CHECK: ret i32 [[RET]]
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// CHECK: }
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public func test_uint64() -> UInt64 {
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let p = VolatileMappedRegister<UInt64>(unsafeBitPattern: 0xf000baaa)
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p.store(42)
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return p.load()
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}
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// CHECK: define {{.*}}i64 @"$s4main11test_uint64s6UInt64VyF"()
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// CHECK: store atomic volatile i64 42, ptr {{.*}} monotonic, align 8
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// CHECK: [[RET:%.*]] = load atomic volatile i64, ptr {{.*}} monotonic, align 8
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// CHECK: ret i64 [[RET]]
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// CHECK: }

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