Merge pull request swiftlang#34172 from rjmccall/compiler-abstraction

[NFC] A trio of patches to improve incremental build times and compiler abstraction

Author: rjmccall

cmake/modules/AddSwift.cmake

@@ -630,3 +630,9 @@ macro(add_swift_tool_symlink name dest component)
   add_llvm_tool_symlink(${name} ${dest} ALWAYS_GENERATE)
   llvm_install_symlink(${name} ${dest} ALWAYS_GENERATE COMPONENT ${component})
 endmacro()
+
+# Declare that files in this library are built with LLVM's support
+# libraries available.
+macro(set_swift_llvm_is_available)
+  add_compile_options(-DSWIFT_LLVM_SUPPORT_IS_AVAILABLE)
+endmacro()

include/swift/ABI/Metadata.h

@@ -38,7 +38,7 @@
 #include "swift/Basic/RelativePointer.h"
 #include "swift/Demangling/Demangle.h"
 #include "swift/Demangling/ManglingMacros.h"
-#include "swift/Runtime/Unreachable.h"
+#include "swift/Basic/Unreachable.h"
 #include "../../../stdlib/public/SwiftShims/HeapObject.h"
 #if SWIFT_OBJC_INTEROP
 #include <objc/runtime.h>
@@ -4664,7 +4664,7 @@ int32_t TargetTypeContextDescriptor<Runtime>::getGenericArgumentOffset() const {
     return llvm::cast<TargetStructDescriptor<Runtime>>(this)
         ->getGenericArgumentOffset();
   default:
-    swift_runtime_unreachable("Not a type context descriptor.");
+    swift_unreachable("Not a type context descriptor.");
   }
 }
 
@@ -4682,7 +4682,7 @@ TargetTypeContextDescriptor<Runtime>::getFullGenericContextHeader() const {
     return llvm::cast<TargetStructDescriptor<Runtime>>(this)
         ->getFullGenericContextHeader();
   default:
-    swift_runtime_unreachable("Not a type context descriptor.");
+    swift_unreachable("Not a type context descriptor.");
   }
 }
 
@@ -4699,7 +4699,7 @@ TargetTypeContextDescriptor<Runtime>::getGenericParams() const {
   case ContextDescriptorKind::OpaqueType:
     return llvm::cast<TargetOpaqueTypeDescriptor<Runtime>>(this)->getGenericParams();
   default:
-    swift_runtime_unreachable("Not a type context descriptor.");
+    swift_unreachable("Not a type context descriptor.");
   }
 }
 
@@ -4717,7 +4717,7 @@ TargetTypeContextDescriptor<Runtime>::getForeignMetadataInitialization() const {
     return llvm::cast<TargetStructDescriptor<Runtime>>(this)
         ->getForeignMetadataInitialization();
   default:
-    swift_runtime_unreachable("Not a type context descriptor.");
+    swift_unreachable("Not a type context descriptor.");
   }
 }
 
@@ -4735,7 +4735,7 @@ TargetTypeContextDescriptor<Runtime>::getSingletonMetadataInitialization() const
     return llvm::cast<TargetClassDescriptor<Runtime>>(this)
         ->getSingletonMetadataInitialization();
   default:
-    swift_runtime_unreachable("Not a enum, struct or class type descriptor.");
+    swift_unreachable("Not a enum, struct or class type descriptor.");
   }
 }
 
@@ -4753,7 +4753,7 @@ TargetTypeContextDescriptor<Runtime>::getCanonicicalMetadataPrespecializations()
     return llvm::cast<TargetClassDescriptor<Runtime>>(this)
         ->getCanonicicalMetadataPrespecializations();
   default:
-    swift_runtime_unreachable("Not a type context descriptor.");
+    swift_unreachable("Not a type context descriptor.");
   }
 }
 

include/swift/ABI/MetadataValues.h

@@ -20,10 +20,10 @@
 #define SWIFT_ABI_METADATAVALUES_H
 
 #include "swift/ABI/KeyPath.h"
+#include "swift/ABI/ProtocolDispatchStrategy.h"
 #include "swift/AST/Ownership.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/FlagSet.h"
-#include "swift/Runtime/Unreachable.h"
 
 #include <stdlib.h>
 #include <stdint.h>
@@ -410,20 +410,6 @@ enum class SpecialProtocol: uint8_t {
   Error = 1,
 };
 
-/// Identifiers for protocol method dispatch strategies.
-enum class ProtocolDispatchStrategy: uint8_t {
-  /// Uses ObjC method dispatch.
-  ///
-  /// This must be 0 for ABI compatibility with Objective-C protocol_t records.
-  ObjC = 0,
-  
-  /// Uses Swift protocol witness table dispatch.
-  ///
-  /// To invoke methods of this protocol, a pointer to a protocol witness table
-  /// corresponding to the protocol conformance must be available.
-  Swift = 1,
-};
-
 /// Flags for protocol descriptors.
 class ProtocolDescriptorFlags {
   typedef uint32_t int_type;
@@ -486,18 +472,7 @@ class ProtocolDescriptorFlags {
 
   /// Does the protocol require a witness table for method dispatch?
   bool needsWitnessTable() const {
-    return needsWitnessTable(getDispatchStrategy());
-  }
-  
-  static bool needsWitnessTable(ProtocolDispatchStrategy strategy) {
-    switch (strategy) {
-    case ProtocolDispatchStrategy::ObjC:
-      return false;
-    case ProtocolDispatchStrategy::Swift:
-      return true;
-    }
-
-    swift_runtime_unreachable("Unhandled ProtocolDispatchStrategy in switch.");
+    return swift::protocolRequiresWitnessTable(getDispatchStrategy());
   }
 
   /// Return the identifier if this is a special runtime-known protocol.

include/swift/ABI/ProtocolDispatchStrategy.h

@@ -0,0 +1,54 @@
+//===--- ProtocolDispatchStrategy.h - ---------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This header declares the ProtocolDispatchStrategy enum and some
+// related operations.  It's split out because we would otherwise need
+// to include MetadataValues.h in some relatively central headers.s
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_ABI_PROTOCOLDISPATCHSTRATEGY_H
+#define SWIFT_ABI_PROTOCOLDISPATCHSTRATEGY_H
+
+#include "swift/Basic/Unreachable.h"
+
+namespace swift {
+
+/// Identifiers for protocol method dispatch strategies.
+enum class ProtocolDispatchStrategy: uint8_t {
+  /// Uses ObjC method dispatch.
+  ///
+  /// This must be 0 for ABI compatibility with Objective-C protocol_t records.
+  ObjC = 0,
+  
+  /// Uses Swift protocol witness table dispatch.
+  ///
+  /// To invoke methods of this protocol, a pointer to a protocol witness table
+  /// corresponding to the protocol conformance must be available.
+  Swift = 1,
+};
+
+/// Does a protocol using the given strategy require a witness table?
+inline bool protocolRequiresWitnessTable(ProtocolDispatchStrategy strategy) {
+  switch (strategy) {
+  case ProtocolDispatchStrategy::ObjC:
+    return false;
+  case ProtocolDispatchStrategy::Swift:
+    return true;
+  }
+
+  swift_unreachable("Unhandled ProtocolDispatchStrategy in switch.");
+}
+
+}
+
+#endif

include/swift/Basic/Compiler.h

@@ -34,10 +34,59 @@
 #define SWIFT_ASSUME(x)
 #endif
 
+/// Attributes.
+
 #if __has_attribute(constructor)
 #define SWIFT_CONSTRUCTOR __attribute__((constructor))
 #else
 #define SWIFT_CONSTRUCTOR
 #endif
 
+/// \macro SWIFT_GNUC_PREREQ
+/// Extend the default __GNUC_PREREQ even if glibc's features.h isn't
+/// available.
+#ifndef SWIFT_GNUC_PREREQ
+# if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__)
+#  define SWIFT_GNUC_PREREQ(maj, min, patch) \
+    ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) + __GNUC_PATCHLEVEL__ >= \
+     ((maj) << 20) + ((min) << 10) + (patch))
+# elif defined(__GNUC__) && defined(__GNUC_MINOR__)
+#  define SWIFT_GNUC_PREREQ(maj, min, patch) \
+    ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) >= ((maj) << 20) + ((min) << 10))
+# else
+#  define SWIFT_GNUC_PREREQ(maj, min, patch) 0
+# endif
+#endif
+
+
+/// SWIFT_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so,
+/// mark a method "not for inlining".
+#if __has_attribute(noinline) || SWIFT_GNUC_PREREQ(3, 4, 0)
+#define SWIFT_ATTRIBUTE_NOINLINE __attribute__((noinline))
+#elif defined(_MSC_VER)
+#define SWIFT_ATTRIBUTE_NOINLINE __declspec(noinline)
+#else
+#define SWIFT_ATTRIBUTE_NOINLINE
+#endif
+
+/// SWIFT_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do
+/// so, mark a method "always inline" because it is performance sensitive. GCC
+/// 3.4 supported this but is buggy in various cases and produces unimplemented
+/// errors, just use it in GCC 4.0 and later.
+#if __has_attribute(always_inline) || SWIFT_GNUC_PREREQ(4, 0, 0)
+#define SWIFT_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline))
+#elif defined(_MSC_VER)
+#define SWIFT_ATTRIBUTE_ALWAYS_INLINE __forceinline
+#else
+#define SWIFT_ATTRIBUTE_ALWAYS_INLINE
+#endif
+
+#ifdef __GNUC__
+#define SWIFT_ATTRIBUTE_NORETURN __attribute__((noreturn))
+#elif defined(_MSC_VER)
+#define SWIFT_ATTRIBUTE_NORETURN __declspec(noreturn)
+#else
+#define SWIFT_ATTRIBUTE_NORETURN
+#endif
+
 #endif // SWIFT_BASIC_COMPILER_H

include/swift/Runtime/Unreachable.h renamed to include/swift/Basic/Unreachable.h

@@ -1,4 +1,4 @@
-//===--- Unreachable.h - Implements swift_runtime_unreachable ---*- C++ -*-===//
+//===--- Unreachable.h - Implements swift_unreachable ---*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //
@@ -10,24 +10,38 @@
 //
 //===----------------------------------------------------------------------===//
 //
-//  This file defines swift_runtime_unreachable, an LLVM-independent
-//  implementation of llvm_unreachable.
+//  This file defines swift_unreachable, which provides the
+//  functionality of llvm_unreachable without necessarily depending on
+//  the LLVM support libraries.
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef SWIFT_RUNTIME_UNREACHABLE_H
-#define SWIFT_RUNTIME_UNREACHABLE_H
+#ifndef SWIFT_BASIC_UNREACHABLE_H
+#define SWIFT_BASIC_UNREACHABLE_H
+
+#ifdef SWIFT_LLVM_SUPPORT_IS_AVAILABLE
+
+// The implementation when LLVM is available.
+
+#include "llvm/Support/ErrorHandling.h"
+#define swift_unreachable llvm_unreachable
+
+#else
+
+// The implementation when LLVM is not available.
 
 #include <assert.h>
 #include <stdlib.h>
 
 #include "swift/Runtime/Config.h"
 
 SWIFT_RUNTIME_ATTRIBUTE_NORETURN
-inline static void swift_runtime_unreachable(const char *msg) {
+inline static void swift_unreachable(const char *msg) {
   assert(false && msg);
   (void)msg;
   abort();
 }
 
-#endif // SWIFT_RUNTIME_UNREACHABLE_H
+#endif
+
+#endif

include/swift/Demangling/TypeDecoder.h

@@ -24,7 +24,7 @@
 #include "swift/Demangling/Demangler.h"
 #include "swift/Demangling/NamespaceMacros.h"
 #include "swift/Runtime/Portability.h"
-#include "swift/Runtime/Unreachable.h"
+#include "swift/Basic/Unreachable.h"
 #include "swift/Strings.h"
 #include "llvm/ADT/ArrayRef.h"
 #include <vector>

include/swift/Reflection/ReflectionContext.h

@@ -33,7 +33,7 @@
 #include "swift/Reflection/TypeLowering.h"
 #include "swift/Reflection/TypeRef.h"
 #include "swift/Reflection/TypeRefBuilder.h"
-#include "swift/Runtime/Unreachable.h"
+#include "swift/Basic/Unreachable.h"
 
 #include <set>
 #include <unordered_map>
@@ -1302,7 +1302,7 @@ class ReflectionContext
       return true;
     }
 
-    swift_runtime_unreachable("Unhandled MetadataSourceKind in switch.");
+    swift_unreachable("Unhandled MetadataSourceKind in switch.");
   }
 
   /// Read metadata for a captured generic type from a closure context.

include/swift/Reflection/TypeRef.h

@@ -22,7 +22,7 @@
 #include "llvm/Support/Casting.h"
 #include "swift/ABI/MetadataValues.h"
 #include "swift/Remote/MetadataReader.h"
-#include "swift/Runtime/Unreachable.h"
+#include "swift/Basic/Unreachable.h"
 
 namespace swift {
 namespace reflection {
@@ -856,7 +856,7 @@ class TypeRefVisitor {
 #include "swift/Reflection/TypeRefs.def"
     }
 
-    swift_runtime_unreachable("Unhandled TypeRefKind in switch.");
+    swift_unreachable("Unhandled TypeRefKind in switch.");
   }
 };
 

include/swift/Remote/MetadataReader.h

@@ -28,7 +28,7 @@
 #include "swift/ABI/TypeIdentity.h"
 #include "swift/Runtime/ExistentialContainer.h"
 #include "swift/Runtime/HeapObject.h"
-#include "swift/Runtime/Unreachable.h"
+#include "swift/Basic/Unreachable.h"
 
 #include <vector>
 #include <unordered_map>
@@ -923,7 +923,7 @@ class MetadataReader {
     }
     }
 
-    swift_runtime_unreachable("Unhandled MetadataKind in switch");
+    swift_unreachable("Unhandled MetadataKind in switch");
   }
 
   TypeLookupErrorOr<typename BuilderType::BuiltType>
@@ -1295,7 +1295,7 @@ class MetadataReader {
     }
     }
 
-    swift_runtime_unreachable("Unhandled IsaEncodingKind in switch.");
+    swift_unreachable("Unhandled IsaEncodingKind in switch.");
   }
 
   /// Read the offset of the generic parameters of a class from the nominal