Merge pull request #74952 from drexin/wip-129627898

[IRGen] Always load extra tag bits as full bytes in CVW to avoid elem…

Author: drexin

lib/IRGen/GenEnum.cpp

@@ -1688,11 +1688,22 @@ namespace {
       auto payload = EnumPayload::load(IGF, projectPayload(IGF, addr),
                                        PayloadSchema);
       if (ExtraTagBitCount > 0) {
-        extraTag = IGF.Builder.CreateLoad(projectExtraTagBits(IGF, addr));
         if (maskExtraTagBits) {
-          auto maskBits = llvm::NextPowerOf2(NumExtraTagValues) - 1;
+          auto projectedBits = projectExtraTagBits(IGF, addr);
+          // LLVM assumes that loads of fractional byte sizes have been stored
+          // with the same type, so all unused bits would be 0. Since we are
+          // re-using spare bits for tag storage, that assumption is wrong here.
+          // In CVW we have to mask the extra bits, which requires us to make
+          // this cast here, otherwise LLVM would optimize away the bit mask.
+          if (projectedBits.getElementType()->getIntegerBitWidth() < 8) {
+            projectedBits = IGF.Builder.CreateElementBitCast(addr, IGM.Int8Ty);
+          }
+          extraTag = IGF.Builder.CreateLoad(projectedBits);
+          auto maskBits = llvm::PowerOf2Ceil(NumExtraTagValues) - 1;
           auto mask = llvm::ConstantInt::get(extraTag->getType(), maskBits);
           extraTag = IGF.Builder.CreateAnd(extraTag, mask);
+        } else {
+          extraTag = IGF.Builder.CreateLoad(projectExtraTagBits(IGF, addr));
         }
       }
       return {std::move(payload), extraTag};

test/Interpreter/Inputs/layout_string_witnesses_types.swift

@@ -619,6 +619,16 @@ public enum MultiPayloadError {
     case error2(Int, Error)
 }
 
+public enum TwoPayloadInner {
+    case x(AnyObject)
+    case y(Int)
+}
+
+public enum TwoPayloadOuter {
+    case x(Int)
+    case y(TwoPayloadInner)
+}
+
 @inline(never)
 public func consume<T>(_ x: T.Type) {
     withExtendedLifetime(x) {}

test/Interpreter/layout_string_witnesses_static.swift

@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -I %S/Inputs/CTypes -enable-experimental-feature LayoutStringValueWitnesses -enable-layout-string-value-witnesses -parse-stdlib -emit-module -emit-module-path=%t/layout_string_witnesses_types.swiftmodule %S/Inputs/layout_string_witnesses_types.swift
+// RUN: %target-swift-frontend -O -I %S/Inputs/CTypes -enable-experimental-feature LayoutStringValueWitnesses -enable-layout-string-value-witnesses -parse-stdlib -emit-module -emit-module-path=%t/layout_string_witnesses_types.swiftmodule %S/Inputs/layout_string_witnesses_types.swift
 
 // NOTE: We have to build this as dylib to turn private external symbols into local symbols, so we can observe potential issues with linkage
-// RUN: %target-build-swift-dylib(%t/%target-library-name(layout_string_witnesses_types)) -I %S/Inputs/CTypes -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnesses -Xfrontend -enable-layout-string-value-witnesses -Xfrontend -parse-stdlib -parse-as-library %S/Inputs/layout_string_witnesses_types.swift
+// RUN: %target-build-swift-dylib(%t/%target-library-name(layout_string_witnesses_types)) -O -I %S/Inputs/CTypes -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnesses -Xfrontend -enable-layout-string-value-witnesses -Xfrontend -parse-stdlib -parse-as-library %S/Inputs/layout_string_witnesses_types.swift
 // RUN: %target-codesign %t/%target-library-name(layout_string_witnesses_types)
-// RUN: %target-swift-frontend -enable-experimental-feature LayoutStringValueWitnesses -enable-layout-string-value-witnesses -enable-library-evolution -emit-module -emit-module-path=%t/layout_string_witnesses_types_resilient.swiftmodule %S/Inputs/layout_string_witnesses_types_resilient.swift
-// RUN: %target-build-swift -g -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnesses -Xfrontend -enable-layout-string-value-witnesses -Xfrontend -enable-library-evolution -c -parse-as-library -o %t/layout_string_witnesses_types_resilient.o %S/Inputs/layout_string_witnesses_types_resilient.swift
-// RUN: %target-build-swift -g -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnesses -Xfrontend -enable-layout-string-value-witnesses -Xfrontend -enable-type-layout -Xfrontend -parse-stdlib -module-name layout_string_witnesses_static -llayout_string_witnesses_types -L%t %t/layout_string_witnesses_types_resilient.o -I %t -o %t/main %s %target-rpath(%t)
+// RUN: %target-swift-frontend -O -enable-experimental-feature LayoutStringValueWitnesses -enable-layout-string-value-witnesses -enable-library-evolution -emit-module -emit-module-path=%t/layout_string_witnesses_types_resilient.swiftmodule %S/Inputs/layout_string_witnesses_types_resilient.swift
+// RUN: %target-build-swift -O -g -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnesses -Xfrontend -enable-layout-string-value-witnesses -Xfrontend -enable-library-evolution -c -parse-as-library -o %t/layout_string_witnesses_types_resilient.o %S/Inputs/layout_string_witnesses_types_resilient.swift
+// RUN: %target-build-swift -O -g -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnesses -Xfrontend -enable-layout-string-value-witnesses -Xfrontend -enable-type-layout -Xfrontend -parse-stdlib -module-name layout_string_witnesses_static -llayout_string_witnesses_types -L%t %t/layout_string_witnesses_types_resilient.o -I %t -o %t/main %s %target-rpath(%t)
 // RUN: %target-codesign %t/main
 // RUN: %target-run %t/main %t/%target-library-name(layout_string_witnesses_types) | %FileCheck %s --check-prefix=CHECK -check-prefix=CHECK-%target-os
 
@@ -1290,6 +1290,35 @@ func testCTypeUnderAligned() {
 
 testCTypeUnderAligned()
 
+func testNestedTwoPayload() {
+    let ptr = UnsafeMutablePointer<TwoPayloadOuter>.allocate(capacity: 1)
+
+    do {
+        let x = TwoPayloadOuter.y(TwoPayloadInner.x(SimpleClass(x: 23)))
+        testInit(ptr, to: x)
+    }
+
+    do {
+        let y = TwoPayloadOuter.y(TwoPayloadInner.x(SimpleClass(x: 1)))
+
+        // CHECK: Before deinit
+        print("Before deinit")
+
+        // CHECK-NEXT: SimpleClass deinitialized!
+        testAssign(ptr, from: y)
+    }
+
+    // CHECK-NEXT: Before deinit
+    print("Before deinit")
+
+    // CHECK-NEXT: SimpleClass deinitialized!
+    testDestroy(ptr)
+
+    ptr.deallocate()
+}
+
+testNestedTwoPayload()
+
 #if os(macOS)
 func testObjc() {
     let ptr = UnsafeMutablePointer<ObjcWrapper>.allocate(capacity: 1)