[Volatile] Add a -enable-experimental-feature Volatile

Author: kubamracek

include/swift/AST/DiagnosticsSema.def

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

include/swift/Basic/Features.def

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

lib/AST/FeatureSet.cpp

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

lib/Sema/ImportResolution.cpp

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

test/Volatile/volatile-feature-flag.swift

@@ -0,0 +1,8 @@
+// RUN: %empty-directory(%t)
+// RUN: not %target-swift-emit-ir %s -module-name main -parse-as-library 2>&1 | %FileCheck %s
+// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Volatile
+// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Embedded
+
+import _Volatile
+
+// CHECK: importing _Volatile module requires '-enable-experimental-feature Volatile'

test/Volatile/volatile-ir.swift

@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -Onone | %FileCheck %s
-// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -O | %FileCheck %s
-// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -Osize | %FileCheck %s
+// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Volatile -Onone | %FileCheck %s
+// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Volatile -O | %FileCheck %s
+// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Volatile -Osize | %FileCheck %s
 
 import _Volatile
 
 public func test_uint8() -> UInt8 {
-  let p = VolatileMappedRegister<UInt8>(bitPattern: 0xf000baaa)
+  let p = VolatileMappedRegister<UInt8>(unsafeBitPattern: 0xf000baaa)
   p.store(42)
   return p.load()
 }
@@ -18,7 +18,7 @@ public func test_uint8() -> UInt8 {
 // CHECK: }
 
 public func test_uint16() -> UInt16 {
-  let p = VolatileMappedRegister<UInt16>(bitPattern: 0xf000baaa)
+  let p = VolatileMappedRegister<UInt16>(unsafeBitPattern: 0xf000baaa)
   p.store(42)
   return p.load()
 }
@@ -30,7 +30,7 @@ public func test_uint16() -> UInt16 {
 // CHECK: }
 
 public func test_uint32() -> UInt32 {
-  let p = VolatileMappedRegister<UInt32>(bitPattern: 0xf000baaa)
+  let p = VolatileMappedRegister<UInt32>(unsafeBitPattern: 0xf000baaa)
   p.store(42)
   return p.load()
 }
@@ -42,7 +42,7 @@ public func test_uint32() -> UInt32 {
 // CHECK: }
 
 public func test_uint64() -> UInt64 {
-  let p = VolatileMappedRegister<UInt64>(bitPattern: 0xf000baaa)
+  let p = VolatileMappedRegister<UInt64>(unsafeBitPattern: 0xf000baaa)
   p.store(42)
   return p.load()
 }

test/Volatile/volatile-repeat-loads.swift

@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -Onone | %FileCheck %s
-// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -O | %FileCheck %s
-// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -Osize | %FileCheck %s
+// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Volatile -Onone | %FileCheck %s
+// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Volatile -O | %FileCheck %s
+// RUN: %target-swift-emit-ir %s -module-name main -parse-as-library -enable-experimental-feature Volatile -Osize | %FileCheck %s
 
 import _Volatile
 
 public func test_volatilepointer() -> UInt8 {
-  let p = VolatileMappedRegister<UInt8>(bitPattern: 0xf000baaa)
+  let p = VolatileMappedRegister<UInt8>(unsafeBitPattern: 0xf000baaa)
   p.store(42)
   let a = p.load()
   let b = p.load()