[Runtime] Fast lookups of Concurrency types with standard manglings.

Have the Concurrency runtime register a struct containing pointers to all of its type descriptors with standard manglings. Then have the runtime use that struct to quickly look up those types, instead of using the standard, slower type lookup code.

rdar://109783861

Author: mikeash

include/swift/Runtime/Metadata.h

@@ -992,6 +992,21 @@ void swift_enableDynamicReplacementScope(const DynamicReplacementScope *scope);
 SWIFT_RUNTIME_EXPORT
 void swift_disableDynamicReplacementScope(const DynamicReplacementScope *scope);
 
+/// A struct containing pointers to all of the type descriptors in the
+/// Concurrency runtime which have standard manglings.
+struct ConcurrencyStandardTypeDescriptors {
+#define STANDARD_TYPE(KIND, MANGLING, TYPENAME)
+#define STANDARD_TYPE_CONCURRENCY(KIND, MANGLING, TYPENAME)                    \
+  const ContextDescriptor *TYPENAME;
+#include "swift/Demangling/StandardTypesMangling.def"
+};
+
+/// Register the type descriptors with standard manglings from the Concurrency
+/// runtime. The passed-in struct must be immortal.
+SWIFT_RUNTIME_STDLIB_SPI
+void _swift_registerConcurrencyStandardTypeDescriptors(
+    const ConcurrencyStandardTypeDescriptors *descriptors);
+
 #pragma clang diagnostic pop
 
 } // end namespace swift

stdlib/public/Concurrency/CMakeLists.txt

@@ -107,6 +107,7 @@ add_swift_target_library(swift_Concurrency ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} I
   GlobalActor.swift
   MainActor.swift
   PartialAsyncTask.swift
+  Setup.cpp
   SourceCompatibilityShims.swift
   Task.cpp
   Task.swift

stdlib/public/Concurrency/Setup.cpp

@@ -0,0 +1,47 @@
+//===--- Setup.cpp - Load-time setup code ---------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/Runtime/Metadata.h"
+
+// Helper macros for figuring out the mangled name of a context descriptor.
+#define DESCRIPTOR_MANGLING_SUFFIX_Structure Mn
+#define DESCRIPTOR_MANGLING_SUFFIX_Class Mn
+#define DESCRIPTOR_MANGLING_SUFFIX_Enum Mn
+#define DESCRIPTOR_MANGLING_SUFFIX_Protocol Mp
+
+#define DESCRIPTOR_MANGLING_SUFFIX_(X) X
+#define DESCRIPTOR_MANGLING_SUFFIX(KIND)                                       \
+  DESCRIPTOR_MANGLING_SUFFIX_(DESCRIPTOR_MANGLING_SUFFIX_##KIND)
+
+#define DESCRIPTOR_MANGLING_(CHAR, SUFFIX) $sSc##CHAR##SUFFIX
+#define DESCRIPTOR_MANGLING(CHAR, SUFFIX) DESCRIPTOR_MANGLING_(CHAR, SUFFIX)
+
+// Declare context descriptors for all of the concurrency descriptors with
+// standard manglings.
+#define STANDARD_TYPE(KIND, MANGLING, TYPENAME)
+#define STANDARD_TYPE_CONCURRENCY(KIND, MANGLING, TYPENAME)                    \
+  extern "C" const swift::ContextDescriptor DESCRIPTOR_MANGLING(               \
+      MANGLING, DESCRIPTOR_MANGLING_SUFFIX(KIND));
+#include "swift/Demangling/StandardTypesMangling.def"
+
+// Register our type descriptors with standard manglings when the concurrency
+// runtime is loaded. This allows the runtime to quickly resolve those standard
+// manglings.
+__attribute__((constructor)) static void setupStandardConcurrencyDescriptors() {
+  static const swift::ConcurrencyStandardTypeDescriptors descriptors = {
+#define STANDARD_TYPE(KIND, MANGLING, TYPENAME)
+#define STANDARD_TYPE_CONCURRENCY(KIND, MANGLING, TYPENAME)                    \
+  &DESCRIPTOR_MANGLING(MANGLING, DESCRIPTOR_MANGLING_SUFFIX(KIND)),
+#include "swift/Demangling/StandardTypesMangling.def"
+  };
+  _swift_registerConcurrencyStandardTypeDescriptors(&descriptors);
+}

stdlib/public/runtime/MetadataLookup.cpp

@@ -770,6 +770,8 @@ _searchTypeMetadataRecords(TypeMetadataPrivateState &T,
 
 #include "swift/Demangling/StandardTypesMangling.def"
 
+static const ConcurrencyStandardTypeDescriptors *concurrencyDescriptors;
+
 static const ContextDescriptor *
 _findContextDescriptor(Demangle::NodePointer node,
                        Demangle::Demangler &Dem) {
@@ -797,7 +799,10 @@ _findContextDescriptor(Demangle::NodePointer node,
     }
   // FIXME: When the _Concurrency library gets merged into the Standard Library,
   // we will be able to reference those symbols directly as well.
-#define STANDARD_TYPE_CONCURRENCY(KIND, MANGLING, TYPENAME)
+#define STANDARD_TYPE_CONCURRENCY(KIND, MANGLING, TYPENAME)                    \
+  if (concurrencyDescriptors && name.equals(#TYPENAME)) {                      \
+    return concurrencyDescriptors->TYPENAME;                                   \
+  }
 #if !SWIFT_OBJC_INTEROP
 # define OBJC_INTEROP_STANDARD_TYPE(KIND, MANGLING, TYPENAME)
 #endif
@@ -851,6 +856,11 @@ _findContextDescriptor(Demangle::NodePointer node,
   return foundContext;
 }
 
+void swift::_swift_registerConcurrencyStandardTypeDescriptors(
+    const ConcurrencyStandardTypeDescriptors *descriptors) {
+  concurrencyDescriptors = descriptors;
+}
+
 #pragma mark Protocol descriptor cache
 namespace {
   struct ProtocolSection {