[Volatile] Add executable tests for VolatileMappedRegister

Author: kubamracek

test/Volatile/volatile-exec.swift

@@ -0,0 +1,30 @@
+// RUN: %target-run-simple-swift(-parse-as-library -enable-experimental-feature Volatile) | %FileCheck %s
+
+// REQUIRES: executable_test
+
+import _Volatile
+
+@main
+struct Main {
+  static func main() {
+    var byte: UInt8 = 42
+    withUnsafePointer(to: &byte) { p in
+      let volatilePointer = VolatileMappedRegister<UInt8>(unsafeBitPattern: UInt(bitPattern: p))
+      print("byte = \(volatilePointer.load())")
+      // CHECK: byte = 42
+      volatilePointer.store(77)
+    }
+    print("byte = \(byte)")
+    // CHECK: byte = 77
+
+    var heapPointer = UnsafeMutablePointer<UInt8>.allocate(capacity: 16) // uninitialized content
+    for i in 0 ..< 16 {
+      let pointerWithOffset = heapPointer.advanced(by: i)
+      let volatilePointer = VolatileMappedRegister<UInt8>(unsafeBitPattern: UInt(bitPattern: pointerWithOffset))
+      volatilePointer.store(UInt8(0x61 + i))
+    }
+    heapPointer[15] = 0
+    print(String(cString: heapPointer))
+    // CHECK: abcdefghijklmno
+  }
+}

test/embedded/volatile-exec.swift

@@ -0,0 +1,39 @@
+// RUN: %target-run-simple-swift(-parse-as-library -enable-experimental-feature Embedded -wmo -runtime-compatibility-version none) | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: executable_test
+// REQUIRES: optimized_stdlib
+// REQUIRES: OS=macosx || OS=linux-gnu
+
+import _Volatile
+
+@_silgen_name("putchar")
+@discardableResult
+func putchar(_: CInt) -> CInt
+
+@main
+struct Main {
+  static func main() {
+    var byte: UInt8 = 42
+    withUnsafePointer(to: &byte) { p in
+      let volatilePointer = VolatileMappedRegister<UInt8>(unsafeBitPattern: UInt(bitPattern: p))
+      print("byte = ", terminator: "")
+      print(volatilePointer.load())
+      // CHECK: byte = 42
+      volatilePointer.store(77)
+    }
+    print("byte = ", terminator: "")
+    print(byte)
+    // CHECK: byte = 77
+
+    var heapPointer = UnsafeMutablePointer<UInt8>.allocate(capacity: 16) // uninitialized content
+    for i in 0 ..< 16 {
+      let pointerWithOffset = heapPointer.advanced(by: i)
+      let volatilePointer = VolatileMappedRegister<UInt8>(unsafeBitPattern: UInt(bitPattern: pointerWithOffset))
+      volatilePointer.store(UInt8(0x61 + i))
+    }
+    for i in 0 ..< 16 { putchar(CInt(heapPointer[i])) }
+    putchar(CInt(("\n" as Unicode.Scalar).value))
+    // CHECK: abcdefghijklmnop
+  }
+}