Support building swift/AST with MSVC on Windows

Author: hughbe

include/swift/AST/AnyFunctionRef.h

@@ -149,7 +149,12 @@ class AnyFunctionRef {
     }
     llvm_unreachable("unexpected AnyFunctionRef representation");
   }
-  
+
+// Disable "only for use within the debugger" warning.
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable: 4996)
+#endif
   LLVM_ATTRIBUTE_DEPRECATED(void dump() const LLVM_ATTRIBUTE_USED,
                             "only for use within the debugger") {
     if (auto afd = TheFunction.dyn_cast<AbstractFunctionDecl *>()) {
@@ -171,6 +176,9 @@ class AnyFunctionRef {
     llvm_unreachable("unexpected AnyFunctionRef representation");
   }
 };
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
 
 } // namespace swift
 

include/swift/AST/Decl.h

@@ -863,7 +863,11 @@ class alignas(1 << DeclAlignInBits) Decl {
 
   // Make vanilla new/delete illegal for Decls.
   void *operator new(size_t Bytes) = delete;
+
+  // Work around MSVC error: attempting to reference a deleted function.
+#if !defined(_MSC_VER) || defined(__clang__)
   void operator delete(void *Data) = delete;
+#endif
 
   // Only allow allocation of Decls using the allocator in ASTContext
   // or by doing a placement new.

include/swift/AST/Expr.h

@@ -662,13 +662,27 @@ class TrailingCallArguments
     return *static_cast<const Derived *>(this);
   }
 
+  // Work around MSVC bug: can't infer llvm::trailing_objects_internal,
+  // even though we granted friend access to it.
   size_t numTrailingObjects(
+#if defined(_MSC_VER) && !defined(__clang__)
+      llvm::trailing_objects_internal::TrailingObjectsBase::OverloadToken<
+      Identifier>) const {
+#else
       typename TrailingObjects::template OverloadToken<Identifier>) const {
+#endif
     return asDerived().getNumArguments();
   }
 
+  // Work around MSVC bug: can't infer llvm::trailing_objects_internal,
+  // even though we granted friend access to it.
   size_t numTrailingObjects(
+#if defined(_MSC_VER) && !defined(__clang__)
+      llvm::trailing_objects_internal::TrailingObjectsBase::OverloadToken<
+      SourceLoc>) const {
+#else
       typename TrailingObjects::template OverloadToken<SourceLoc>) const {
+#endif
     return asDerived().hasArgumentLabelLocs()
              ? asDerived().getNumArguments()
              : 0;
@@ -4447,6 +4461,8 @@ class ObjCSelectorExpr : public Expr {
     case ObjCSelectorKind::Setter:
       return true;
     }
+
+    llvm_unreachable("Unhandled ObjcSelectorKind in switch.");
   }
 
   /// Whether this selector references a method.

include/swift/AST/GenericEnvironment.h

@@ -183,7 +183,9 @@ class alignas(1 << DeclAlignInBits) GenericEnvironment final
 
   /// Make vanilla new/delete illegal.
   void *operator new(size_t Bytes) = delete;
+#if !defined(_MSC_VER) || defined(__clang__)
   void operator delete(void *Data) = delete;
+#endif
 
   /// Only allow placement new.
   void *operator new(size_t Bytes, void *Mem) {

include/swift/AST/Module.h

@@ -506,7 +506,11 @@ class ModuleDecl : public TypeDecl, public DeclContext {
 private:
   // Make placement new and vanilla new/delete illegal for Modules.
   void *operator new(size_t Bytes) throw() = delete;
+
+  // Work around MSVC error: attempting to reference a deleted function.
+#if !defined(_MSC_VER) && !defined(__clang__)
   void operator delete(void *Data) throw() = delete;
+#endif
   void *operator new(size_t Bytes, void *Mem) throw() = delete;
 public:
   // Only allow allocation of Modules using the allocator in ASTContext
@@ -515,6 +519,8 @@ class ModuleDecl : public TypeDecl, public DeclContext {
                      unsigned Alignment = alignof(ModuleDecl));
 };
 
+static inline unsigned alignOfFileUnit();
+
 /// A container for module-scope declarations that itself provides a scope; the
 /// smallest unit of code organization.
 ///
@@ -741,8 +747,12 @@ class FileUnit : public DeclContext {
   // Only allow allocation of FileUnits using the allocator in ASTContext
   // or by doing a placement new.
   void *operator new(size_t Bytes, ASTContext &C,
-                     unsigned Alignment = alignof(FileUnit));
+                     unsigned Alignment = alignOfFileUnit());
 };
+
+static inline unsigned alignOfFileUnit() {
+  return alignof(FileUnit&);
+}
 
 /// A file containing Swift source code.
 ///

include/swift/AST/ProtocolConformance.h

@@ -265,7 +265,11 @@ class alignas(1 << DeclAlignInBits) ProtocolConformance {
 
   // Make vanilla new/delete illegal for protocol conformances.
   void *operator new(size_t bytes) = delete;
+
+  // Work around MSVC error: attempting to reference a deleted function.
+#if !defined(_MSC_VER) || defined(__clang__)
   void operator delete(void *data) = delete;
+#endif
 
   // Only allow allocation of protocol conformances using the allocator in
   // ASTContext or by doing a placement new.

include/swift/AST/TypeMatcher.h

@@ -69,6 +69,8 @@ class TypeMatcher {
                         cast<CLASS##Type>(secondType.getPointer()));
 #include "swift/AST/TypeNodes.def"
       }
+
+      llvm_unreachable("Unhandled TypeKind in switch.");
     }
 
     /// Honeypot to catch cases where we should redispatch the second type, but

include/swift/AST/TypeRepr.h

@@ -42,7 +42,10 @@ enum class TypeReprKind : uint8_t {
 
 /// \brief Representation of a type as written in source.
 class alignas(8) TypeRepr {
+  // Fix MSVC error: attempting to reference a deleted function.
+#if !defined(_MSC_VER) || defined(__clang__)
   TypeRepr(const TypeRepr&) = delete;
+#endif
   void operator=(const TypeRepr&) = delete;
 
   class TypeReprBitfields {

include/swift/AST/Types.h

@@ -1381,7 +1381,7 @@ class ParameterTypeFlags {
     NumBits = 3
   };
   OptionSet<ParameterFlags> value;
-  static_assert(NumBits < 8*sizeof(value), "overflowed");
+  static_assert(NumBits < 8*sizeof(OptionSet<ParameterFlags>), "overflowed");
 
   ParameterTypeFlags(OptionSet<ParameterFlags, uint8_t> val) : value(val) {}
 
@@ -2255,6 +2255,8 @@ inline bool canBeCalledIndirectly(SILFunctionTypeRepresentation rep) {
   case SILFunctionTypeRepresentation::WitnessMethod:
     return true;
   }
+
+  llvm_unreachable("Unhandled SILFunctionTypeRepresentation in switch.");
 }
 
 /// Map a SIL function representation to the base language calling convention
@@ -2273,6 +2275,8 @@ getSILFunctionLanguage(SILFunctionTypeRepresentation rep) {
   case SILFunctionTypeRepresentation::Closure:
     return SILFunctionLanguage::Swift;
   }
+
+  llvm_unreachable("Unhandled SILFunctionTypeRepresentation in switch.");
 }
 
 /// AnyFunctionType - A function type has a single input and result, but
@@ -2357,6 +2361,8 @@ class AnyFunctionType : public TypeBase {
       case SILFunctionTypeRepresentation::WitnessMethod:
         return true;
       }
+
+      llvm_unreachable("Unhandled SILFunctionTypeRepresentation in switch.");
     }
 
     /// True if the function representation carries context.
@@ -2373,6 +2379,8 @@ class AnyFunctionType : public TypeBase {
       case SILFunctionTypeRepresentation::Closure:
         return false;
       }
+
+      llvm_unreachable("Unhandled SILFunctionTypeRepresentation in switch.");
     }
 
     // Note that we don't have setters. That is by design, use
@@ -3043,6 +3051,8 @@ class SILFunctionType final : public TypeBase, public llvm::FoldingSetNode,
       case Representation::WitnessMethod:
         return true;
       }
+
+      llvm_unreachable("Unhandled Representation in switch.");
     }
 
     bool hasGuaranteedSelfParam() const {
@@ -3058,6 +3068,8 @@ class SILFunctionType final : public TypeBase, public llvm::FoldingSetNode,
       case Representation::WitnessMethod:
         return true;
       }
+
+      llvm_unreachable("Unhandled Representation in switch.");
     }
 
     /// True if the function representation carries context.
@@ -3074,6 +3086,8 @@ class SILFunctionType final : public TypeBase, public llvm::FoldingSetNode,
       case Representation::Closure:
         return false;
       }
+
+      llvm_unreachable("Unhandled Representation in switch.");
     }
 
     // Note that we don't have setters. That is by design, use

lib/AST/ASTContext.cpp

@@ -275,8 +275,16 @@ struct ASTContext::Implementation {
     ~Arena() {
       for (auto &conformance : SpecializedConformances)
         conformance.~SpecializedProtocolConformance();
+      // Work around MSVC warning: local variable is initialized but
+      // not referenced.
+#if defined(_MSC_VER)
+#pragma warning (disable: 4189)
+#endif
       for (auto &conformance : InheritedConformances)
         conformance.~InheritedProtocolConformance();
+#if defined(_MSC_VER)
+#pragma warning (default: 4189)
+#endif
 
       // Call the normal conformance destructors last since they could be
       // referenced by the other conformance types.
@@ -536,6 +544,8 @@ EnumDecl *ASTContext::getOptionalDecl(OptionalTypeKind kind) const {
   case OTK_Optional:
     return getOptionalDecl();
   }
+
+  llvm_unreachable("Unhandled OptionalTypeKind in switch.");
 }
 
 static EnumElementDecl *findEnumElement(EnumDecl *e, Identifier name) {
@@ -1714,6 +1724,8 @@ std::pair<unsigned, DeclName> swift::getObjCMethodDiagInfo(
     // Normal method.
     return { 4, func->getFullName() };
   }
+
+  llvm_unreachable("Unhandled AccessorKind in switch.");
 }
 
 bool swift::fixDeclarationName(InFlightDiagnostic &diag, ValueDecl *decl,
@@ -3760,6 +3772,8 @@ ASTContext::getForeignRepresentationInfo(NominalTypeDecl *nominal,
   case ForeignLanguage::ObjectiveC:
     return entry;
   }
+
+  llvm_unreachable("Unhandled ForeignLanguage in switch.");
 }
 
 bool ASTContext::isTypeBridgedInExternalModule(