Some fixes for raw layout types and noncopyable types in the stdlib

Author: Azoy

lib/IRGen/GenMeta.cpp

@@ -3081,7 +3081,8 @@ static void emitInitializeRawLayout(IRGenFunction &IGF, SILType likeType,
   auto initRawAvail = IGF.IGM.Context.getInitRawStructMetadataAvailability();
 
   if (!IGF.IGM.Context.LangOpts.DisableAvailabilityChecking &&
-      !deploymentAvailability.isContainedIn(initRawAvail)) {
+      !deploymentAvailability.isContainedIn(initRawAvail) &&
+      !IGF.IGM.getSwiftModule()->isStdlibModule()) {
     emitInitializeRawLayoutOld(IGF, likeType, count, T, metadata, collector);
     return;
   }

lib/IRGen/GenReflection.cpp

@@ -279,11 +279,28 @@ getTypeRefByFunction(IRGenModule &IGM,
           llvm::Instruction *br = nullptr;
           llvm::BasicBlock *supportedBB = nullptr;
           if (useForwardCompatibility) {
-            auto runtimeSupportsNoncopyableTypesSymbol
-              = IGM.Module.getOrInsertGlobal("swift_runtimeSupportsNoncopyableTypes",
-                                             IGM.Int8Ty);
-            cast<llvm::GlobalVariable>(runtimeSupportsNoncopyableTypesSymbol)
-              ->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
+            llvm::Value *runtimeSupportsNoncopyableTypesSymbol = nullptr;
+
+            // This is weird. When building the stdlib, we don't have access to
+            // the swift_runtimeSupportsNoncopyableTypes symbol in the Swift.o,
+            // so we'll emit an adrp + ldr to resolve the GOT address. However,
+            // this symbol is defined as an abolsute in the runtime object files
+            // to address 0x0 right now and ld doesn't quite understand how to
+            // fixup this GOT address when merging the runtime and stdlib. Just
+            // unconditionally fail the branch.
+            //
+            // Note: When the value of this symbol changes, this MUST be
+            // updated.
+            if (IGM.getSwiftModule()->isStdlibModule()) {
+              runtimeSupportsNoncopyableTypesSymbol
+                  = llvm::ConstantInt::get(IGM.Int8Ty, 0);
+            } else {
+              runtimeSupportsNoncopyableTypesSymbol
+                  = IGM.Module.getOrInsertGlobal(
+                      "swift_runtimeSupportsNoncopyableTypes", IGM.Int8Ty);
+              cast<llvm::GlobalVariable>(runtimeSupportsNoncopyableTypesSymbol)
+                  ->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
+            }
 
             auto runtimeSupportsNoncopyableTypes
               = IGF.Builder.CreateIsNotNull(runtimeSupportsNoncopyableTypesSymbol,

lib/IRGen/GenStruct.cpp

@@ -990,6 +990,29 @@ namespace {
         return IGM.typeLayoutCache.getOrCreateResilientEntry(T);
       }
 
+      auto decl = T.getASTType()->getStructOrBoundGenericStruct();
+      auto rawLayout = decl->getAttrs().getAttribute<RawLayoutAttr>();
+
+      // If we have a raw layout struct who is fixed size, it means the
+      // layout of the struct is fully concrete.
+      if (rawLayout) {
+        auto likeType = rawLayout->getResolvedLikeType(decl)->getCanonicalType();
+        SILType loweredLikeType = IGM.getLoweredType(likeType);
+
+        // The given struct type T that we're building is fully concrete, but
+        // our like type is still in terms of the potential archetype of the
+        // type.
+        auto subs = T.getASTType()->getContextSubstitutionMap(
+          IGM.getSwiftModule(), decl);
+
+        loweredLikeType = loweredLikeType.subst(IGM.getSILModule(), subs);
+
+        // Array like raw layouts are still handled correctly even though the
+        // type layout entry is only that of the like type.
+        return IGM.getTypeInfo(loweredLikeType)
+            .buildTypeLayoutEntry(IGM, loweredLikeType, useStructLayouts);
+      }
+
       std::vector<TypeLayoutEntry *> fields;
       for (auto &field : getFields()) {
         auto fieldTy = field.getType(IGM, T);
@@ -1082,27 +1105,15 @@ namespace {
         return IGM.typeLayoutCache.getOrCreateResilientEntry(T);
       }
 
-      std::vector<TypeLayoutEntry *> fields;
-      for (auto &field : getFields()) {
-        auto fieldTy = field.getType(IGM, T);
-        fields.push_back(
-            field.getTypeInfo().buildTypeLayoutEntry(IGM, fieldTy, useStructLayouts));
-      }
-
       auto decl = T.getASTType()->getStructOrBoundGenericStruct();
       auto rawLayout = decl->getAttrs().getAttribute<RawLayoutAttr>();
 
       // If we have a raw layout struct who is non-fixed size, it means the
       // layout of the struct is dependent on the archetype of the thing it's
       // like.
       if (rawLayout) {
-        SILType loweredLikeType;
-
-        if (auto likeType = rawLayout->getResolvedScalarLikeType(decl)) {
-          loweredLikeType = IGM.getLoweredType(*likeType);
-        } else if (auto likeArray = rawLayout->getResolvedArrayLikeTypeAndCount(decl)) {
-          loweredLikeType = IGM.getLoweredType(likeArray->first);
-        }
+        auto likeType = rawLayout->getResolvedLikeType(decl)->getCanonicalType();
+        SILType loweredLikeType = IGM.getLoweredType(likeType);
 
         // The given struct type T that we're building may be in a generic
         // environment that is different than that which was built our
@@ -1113,10 +1124,18 @@ namespace {
 
         loweredLikeType = loweredLikeType.subst(IGM.getSILModule(), subs);
 
-        return IGM.getTypeInfo(loweredLikeType).buildTypeLayoutEntry(IGM,
-          loweredLikeType, useStructLayouts);
+        // Array like raw layouts are still handled correctly even though the
+        // type layout entry is only that of the like type.
+        return IGM.getTypeInfo(loweredLikeType)
+            .buildTypeLayoutEntry(IGM, loweredLikeType, useStructLayouts);
       }
 
+      std::vector<TypeLayoutEntry *> fields;
+      for (auto &field : getFields()) {
+        auto fieldTy = field.getType(IGM, T);
+        fields.push_back(
+            field.getTypeInfo().buildTypeLayoutEntry(IGM, fieldTy, useStructLayouts));
+      }
       assert(!fields.empty() &&
              "Empty structs should not be NonFixedStructTypeInfo");
 

stdlib/public/runtime/Metadata.cpp

@@ -85,6 +85,9 @@ using namespace metadataimpl;
 // types, so we explicitly define this symbol to be zero for now. Binaries
 // weak-import this symbol so they will resolve it to a zero address on older
 // runtimes as well.
+//
+// Note: If this symbol's value ever gets updated, the corresponding condition
+// handled by IRGen MUST be updated in tandem.
 __asm__("  .globl _swift_runtimeSupportsNoncopyableTypes\n");
 __asm__(".set _swift_runtimeSupportsNoncopyableTypes, 0\n");
 #endif

test/IRGen/Inputs/raw_layout_multifile_b.swift

@@ -1,5 +1,21 @@
+import Builtin
+
 extension Foo where T == Int32 {
 
 }
 
 public func foo(_: borrowing Foo<Int32>) {}
+
+@_rawLayout(like: T)
+public struct UnsafeCell<T>: ~Copyable {
+  var address: UnsafeMutablePointer<T> {
+    .init(Builtin.unprotectedAddressOfBorrow(self))
+  }
+}
+
+@_rawLayout(likeArrayOf: T, count: 3)
+public struct SmallVectorOf3<T>: ~Copyable {
+  var address: UnsafeMutablePointer<T> {
+    .init(Builtin.unprotectedAddressOfBorrow(self))
+  }
+}

test/IRGen/raw_layout.swift

@@ -98,6 +98,16 @@ struct PaddedCell<T>: ~Copyable {}
 @_rawLayout(likeArrayOf: T, count: 8)
 struct SmallVectorBuf<T>: ~Copyable {}
 
+// CHECK-LABEL: @"$s{{[A-Za-z0-9_]*}}14SmallVectorOf3VWV" = {{.*}} %swift.vwtable
+// size
+// CHECK-SAME:  , {{i64|i32}} 0
+// stride
+// CHECK-SAME:  , {{i64|i32}} 0
+// flags: alignment 0, incomplete
+// CHECK-SAME:  , <i32 0x400000>
+@_rawLayout(likeArrayOf: T, count: 3)
+struct SmallVectorOf3<T>: ~Copyable {}
+
 // CHECK-LABEL: @"$s{{[A-Za-z0-9_]*}}8UsesCellVWV" = {{.*}} %swift.vwtable
 // size
 // CHECK-SAME:  , {{i64|i32}} 8
@@ -110,6 +120,28 @@ struct UsesCell: ~Copyable {
     let specialInt: Cell<Int32>
 }
 
+// CHECK-LABEL: @"$s{{[A-Za-z0-9_]*}}13BufferOf3BoolVWV" = {{.*}} %swift.vwtable
+// size
+// CHECK-SAME:  , {{i64|i32}} 3
+// stride
+// CHECK-SAME:  , {{i64|i32}} 3
+// flags: alignment 0, noncopyable
+// CHECK-SAME:  , <i32 0x800000>
+struct BufferOf3Bool: ~Copyable {
+    let buffer: SmallVectorOf3<Bool>
+}
+
+// CHECK-LABEL: @"$s{{[A-Za-z0-9_]*}}9BadBufferVWV" = {{.*}} %swift.vwtable
+// size
+// CHECK-SAME:  , {{i64|i32}} 48
+// stride
+// CHECK-SAME:  , {{i64|i32}} 48
+// flags: alignment 7, noncopyable, is not inline
+// CHECK-SAME:  , <i32 0x820007>
+struct BadBuffer: ~Copyable {
+    let buffer: SmallVectorOf3<Int64?>
+}
+
 // Dependent layout metadata initialization:
 
 // Cell<T>

test/IRGen/raw_layout_multifile.swift

@@ -1,7 +1,40 @@
-// RUN: %target-swift-frontend -enable-experimental-feature RawLayout -emit-ir -primary-file %s %S/Inputs/raw_layout_multifile_b.swift
-// RUN: %target-swift-frontend -enable-experimental-feature RawLayout -emit-ir %s -primary-file %S/Inputs/raw_layout_multifile_b.swift
-
-import Swift
+// RUN: %empty-directory(%t)
+// RUN: %{python} %utils/chex.py < %s > %t/raw_layout_multifile.swift
+// RUN: %target-swift-frontend -enable-experimental-feature BuiltinModule -enable-experimental-feature RawLayout -emit-ir -O -disable-availability-checking %s %S/Inputs/raw_layout_multifile_b.swift | %FileCheck %t/raw_layout_multifile.swift --check-prefix=CHECK --check-prefix=CHECK-%target-ptrsize
 
 @_rawLayout(like: Int32)
 public struct Foo<T>: ~Copyable {}
+
+// CHECK-LABEL: @"$s{{[A-Za-z0-9_]*}}9BadBufferVWV" = {{.*}} %swift.vwtable
+// size
+// CHECK-SAME:  , {{i64|i32}} 48
+// stride
+// CHECK-SAME:  , {{i64|i32}} 48
+// flags: alignment 7, noncopyable, is not inline
+// CHECK-SAME:  , <i32 0x820007>
+struct BadBuffer: ~Copyable {
+  let buf = SmallVectorOf3<Int64?>()
+}
+
+// CHECK-LABEL: @"$s{{[A-Za-z0-9_]*}}5WeirdVWV" = {{.*}} %swift.vwtable
+// size
+// CHECK-SAME:  , {{i64|i32}} 8
+// stride
+// CHECK-SAME:  , {{i64|i32}} 8
+// flags: alignment 7, noncopyable
+// CHECK-SAME:  , <i32 0x800007>
+struct Weird: ~Copyable {
+  let value = UnsafeCell<Int64>()
+}
+
+// Force emission of Weird's descriptor to be lazy...
+public func something() -> Int64 {
+  let x = Weird()
+  return x.value.address.pointee
+}
+
+// Force emission of BadBuffer's descriptor to be lazy...
+public func something2() -> Int64? {
+  let buf = BadBuffer()
+  return buf.buf.address[1]
+}