[metadata prespecialization] On by default.

include/swift/AST/IRGenOptions.h

@@ -262,7 +262,7 @@ class IRGenOptions {
         EnableAnonymousContextMangledNames(false), ForcePublicLinkage(false),
         LazyInitializeClassMetadata(false),
         LazyInitializeProtocolConformances(false), DisableLegacyTypeInfo(false),
-        PrespecializeGenericMetadata(false), UseIncrementalLLVMCodeGen(true),
+        PrespecializeGenericMetadata(true), UseIncrementalLLVMCodeGen(true),
         UseSwiftCall(false), GenerateProfile(false),
         EnableDynamicReplacementChaining(false),
         DisableRoundTripDebugTypes(false), DisableDebuggerShadowCopies(false),

include/swift/Option/FrontendOptions.td

@@ -651,9 +651,9 @@ def disable_verify_exclusivity : Flag<["-"], "disable-verify-exclusivity">,
 def disable_legacy_type_info : Flag<["-"], "disable-legacy-type-info">,
   HelpText<"Completely disable legacy type layout">;
 
-def prespecialize_generic_metadata : Flag<["-"], "prespecialize-generic-metadata">,
-  HelpText<"Statically specialize metadata for generic types at types that "
-           "are known to be used in source.">;
+def disable_generic_metadata_prespecialization : Flag<["-"], "disable-generic-metadata-prespecialization">,
+  HelpText<"Do not statically specialize metadata for generic types at types "
+           "that are known to be used in source.">;
 
 def read_legacy_type_info_path_EQ : Joined<["-"], "read-legacy-type-info-path=">,
   HelpText<"Read legacy type layout from the given path instead of default path">;

lib/Frontend/CompilerInvocation.cpp

@@ -1327,8 +1327,8 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
     Opts.DisableLegacyTypeInfo = true;
   }
 
-  if (Args.hasArg(OPT_prespecialize_generic_metadata)) {
-    Opts.PrespecializeGenericMetadata = true;
+  if (Args.hasArg(OPT_disable_generic_metadata_prespecialization)) {
+    Opts.PrespecializeGenericMetadata = false;
   }
 
   if (const Arg *A = Args.getLastArg(OPT_read_legacy_type_info_path_EQ)) {

lib/IRGen/IRGenModule.cpp

@@ -1340,7 +1340,8 @@ bool IRGenModule::shouldPrespecializeGenericMetadata() {
       AvailabilityContext::forDeploymentTarget(context);
   return IRGen.Opts.PrespecializeGenericMetadata && 
     deploymentAvailability.isContainedIn(
-      context.getPrespecializedGenericMetadataAvailability());
+      context.getPrespecializedGenericMetadataAvailability()) &&
+    (Triple.isOSDarwin() || Triple.isTvOS() || Triple.isOSLinux());
 }
 
 void IRGenerator::addGenModule(SourceFile *SF, IRGenModule *IGM) {

lib/IRGen/MetadataRequest.cpp

@@ -701,36 +701,40 @@ bool irgen::isNominalGenericContextTypeMetadataAccessTrivial(
   auto substitutions =
       type->getContextSubstitutionMap(IGM.getSwiftModule(), &nominal);
 
-  return llvm::all_of(environment->getGenericParams(), [&](auto parameter) {
-    auto conformances =
-        environment->getGenericSignature()->getConformsTo(parameter);
-    auto witnessTablesAreReferenceable =
-        llvm::all_of(conformances, [&](ProtocolDecl *conformance) {
-          return conformance->getModuleContext() == IGM.getSwiftModule() &&
-                 !conformance->isResilient(IGM.getSwiftModule(),
-                                           ResilienceExpansion::Minimal);
-        });
+  auto allWitnessTablesAreReferenceable = llvm::all_of(environment->getGenericParams(), [&](auto parameter) {
+    auto signature = environment->getGenericSignature();
+    auto protocols = signature->getConformsTo(parameter);
     auto argument = ((Type *)parameter)->subst(substitutions);
-    auto genericArgument = argument->getAnyGeneric();
-    // For now, to avoid statically specializing generic protocol witness
-    // tables, don't statically specialize metadata for types any of whose
-    // arguments are generic.
-    //
-    // TODO: This is more pessimistic than necessary.  Specialize even in
-    //       the face of generic arguments so long as those arguments
-    //       aren't required to conform to any protocols.
-    //
+    auto canonicalType = argument->getCanonicalType();
+    auto witnessTablesAreReferenceable = [&]() {
+      return llvm::all_of(protocols, [&](ProtocolDecl *protocol) {
+        auto conformance =
+            signature->lookupConformance(canonicalType, protocol);
+        if (!conformance.isConcrete()) {
+          return false;
+        }
+        auto rootConformance = conformance.getConcrete()->getRootConformance();
+        return !IGM.isDependentConformance(rootConformance) &&
+               !IGM.isResilientConformance(rootConformance);
+      });
+    };
     // TODO: Once witness tables are statically specialized, check whether the
     //       ConformanceInfo returns nullptr from tryGetConstantTable.
-    //       early return.
-    auto isGeneric = genericArgument && genericArgument->isGenericContext();
-    auto isNominal = argument->getNominalOrBoundGenericNominal();
-    auto isExistential = argument->isExistentialType();
-    return isNominal && !isGeneric && !isExistential &&
-           witnessTablesAreReferenceable &&
-           irgen::isTypeMetadataAccessTrivial(IGM,
-                                              argument->getCanonicalType());
-  }) && IGM.getTypeInfoForUnlowered(type).isFixedSize(ResilienceExpansion::Maximal);
+    auto isGenericWithoutPrespecializedConformance = [&]() {
+      auto genericArgument = argument->getAnyGeneric();
+      return genericArgument && genericArgument->isGenericContext() && 
+        (protocols.size() > 0);
+    };
+    auto isExistential = [&]() { return argument->isExistentialType(); };
+    auto metadataAccessIsTrivial = [&]() {
+      return irgen::isTypeMetadataAccessTrivial(IGM,
+                                                argument->getCanonicalType());
+    };
+    return !isGenericWithoutPrespecializedConformance() && !isExistential() && 
+           metadataAccessIsTrivial() && witnessTablesAreReferenceable();
+  });
+  return allWitnessTablesAreReferenceable
+  && IGM.getTypeInfoForUnlowered(type).isFixedSize(ResilienceExpansion::Maximal);
 }
 
 /// Is it basically trivial to access the given metadata?  If so, we don't
@@ -1753,28 +1757,33 @@ static void emitCanonicalSpecializationsForGenericTypeMetadataAccessFunction(
     SmallVector<std::pair<llvm::BasicBlock *, llvm::Value *>, 4>
         specializationBlocks;
     auto switchDestination = llvm::BasicBlock::Create(IGM.getLLVMContext());
-    unsigned long index = 0;
+    unsigned long blockIndex = 0;
     for (auto specialization : specializations) {
-      auto conditionBlock = conditionBlocks[index];
+      auto conditionBlock = conditionBlocks[blockIndex];
       IGF.Builder.emitBlock(conditionBlock);
-      auto successorBlock = index < conditionBlocks.size() - 1
-                                ? conditionBlocks[index + 1]
+      auto successorBlock = blockIndex < conditionBlocks.size() - 1
+                                ? conditionBlocks[blockIndex + 1]
                                 : switchDestination;
       auto specializationBlock = llvm::BasicBlock::Create(IGM.getLLVMContext());
       auto substitutions = specialization->getContextSubstitutionMap(
           IGM.getSwiftModule(), nominal);
 
       llvm::Value *condition = llvm::ConstantInt::get(IGM.Int1Ty, 1);
-      auto generic = specialization->getAnyGeneric();
-      auto parameters = generic->getGenericEnvironment()->getGenericParams();
-      for (size_t index = 0; index < parameters.size(); ++index) {
-        auto parameter = parameters[index];
-        auto argument = ((Type *)parameter)->subst(substitutions);
+      auto nominal = specialization->getAnyNominal();
+      auto requirements = GenericTypeRequirements(IGF.IGM, nominal);
+      int requirementIndex = 0;
+      for (auto requirement : requirements.getRequirements()) {
+        if (requirement.Protocol) {
+          continue;
+        }
+        auto parameter = requirement.TypeParameter;
+        auto argument = parameter.subst(substitutions);
         llvm::Constant *addr =
             IGM.getAddrOfTypeMetadata(argument->getCanonicalType());
         auto addrInt = IGF.Builder.CreateBitCast(addr, IGM.Int8PtrTy);
         condition = IGF.Builder.CreateAnd(
-            condition, IGF.Builder.CreateICmpEQ(addrInt, valueAtIndex(index)));
+            condition, IGF.Builder.CreateICmpEQ(addrInt, valueAtIndex(requirementIndex)));
+        ++requirementIndex;
       }
       IGF.Builder.CreateCondBr(condition, specializationBlock, successorBlock);
 
@@ -1793,7 +1802,7 @@ static void emitCanonicalSpecializationsForGenericTypeMetadataAccessFunction(
       response = IGF.Builder.CreateInsertValue(
           response, state, 1, "insert metadata state into response");
       specializationBlocks.push_back({specializationBlock, response});
-      ++index;
+      ++blockIndex;
     }
 
     for (auto pair : specializationBlocks) {

test/IRGen/conditional_conformances.swift

@@ -1,7 +1,7 @@
-// RUN: %target-swift-frontend -emit-ir %S/../Inputs/conditional_conformance_basic_conformances.swift | %FileCheck %S/../Inputs/conditional_conformance_basic_conformances.swift --check-prefix=CHECK --check-prefix=%target-os
-// RUN: %target-swift-frontend -emit-ir %S/../Inputs/conditional_conformance_with_assoc.swift | %FileCheck %S/../Inputs/conditional_conformance_with_assoc.swift --check-prefix=CHECK --check-prefix=%target-os
-// RUN: %target-swift-frontend -emit-ir %S/../Inputs/conditional_conformance_subclass.swift | %FileCheck %S/../Inputs/conditional_conformance_subclass.swift --check-prefix=CHECK --check-prefix=%target-os
-// RUN: %target-swift-frontend -emit-ir %S/../Inputs/conditional_conformance_recursive.swift | %FileCheck %S/../Inputs/conditional_conformance_recursive.swift --check-prefix=CHECK --check-prefix=%target-os
+// RUN: %target-swift-frontend -disable-generic-metadata-prespecialization -emit-ir %S/../Inputs/conditional_conformance_basic_conformances.swift | %FileCheck %S/../Inputs/conditional_conformance_basic_conformances.swift --check-prefix=CHECK --check-prefix=%target-os
+// RUN: %target-swift-frontend -disable-generic-metadata-prespecialization -emit-ir %S/../Inputs/conditional_conformance_with_assoc.swift | %FileCheck %S/../Inputs/conditional_conformance_with_assoc.swift --check-prefix=CHECK --check-prefix=%target-os
+// RUN: %target-swift-frontend -disable-generic-metadata-prespecialization -emit-ir %S/../Inputs/conditional_conformance_subclass.swift | %FileCheck %S/../Inputs/conditional_conformance_subclass.swift --check-prefix=CHECK --check-prefix=%target-os
+// RUN: %target-swift-frontend -disable-generic-metadata-prespecialization -emit-ir %S/../Inputs/conditional_conformance_recursive.swift | %FileCheck %S/../Inputs/conditional_conformance_recursive.swift --check-prefix=CHECK --check-prefix=%target-os
 
 // Too many pointer-sized integers in the IR
 // REQUIRES: PTRSIZE=64

test/IRGen/conditional_conformances_future.swift

@@ -0,0 +1,9 @@
+// RUN: %target-swift-frontend -target %module-target-future -emit-ir %S/../Inputs/conditional_conformance_basic_conformances.swift | %FileCheck %S/../Inputs/conditional_conformance_basic_conformances_future.swift -DINT=i%target-ptrsize --check-prefix=CHECK --check-prefix=%target-os
+// RUN: %target-swift-frontend -target %module-target-future -emit-ir %S/../Inputs/conditional_conformance_with_assoc.swift | %FileCheck %S/../Inputs/conditional_conformance_with_assoc_future.swift -DINT=i%target-ptrsize --check-prefix=CHECK --check-prefix=%target-os
+// RUN: %target-swift-frontend -target %module-target-future -emit-ir %S/../Inputs/conditional_conformance_subclass.swift | %FileCheck %S/../Inputs/conditional_conformance_subclass_future.swift -DINT=i%target-ptrsize --check-prefix=CHECK --check-prefix=%target-os
+// RUN: %target-swift-frontend -target %module-target-future -emit-ir %S/../Inputs/conditional_conformance_recursive.swift | %FileCheck %S/../Inputs/conditional_conformance_recursive.swift -DINT=i%target-ptrsize --check-prefix=CHECK --check-prefix=%target-os
+
+// Too many pointer-sized integers in the IR
+// REQUIRES: PTRSIZE=64
+// REQUIRES: OS=macosx || OS=ios || OS=tvos || OS=watchos || OS=linux-gnu
+

test/IRGen/conditional_conformances_gettypemetdatabyname.swift

@@ -1,4 +1,5 @@
-// RUN: %target-swift-frontend -target x86_64-apple-macosx10.99 -emit-ir %S/../Inputs/conditional_conformance_basic_conformances.swift | %FileCheck %S/../Inputs/conditional_conformance_basic_conformances.swift --check-prefix=TYPEBYNAME
+// RUN: %target-swift-frontend -disable-generic-metadata-prespecialization -target x86_64-apple-macosx10.99 -emit-ir %S/../Inputs/conditional_conformance_basic_conformances.swift | %FileCheck %S/../Inputs/conditional_conformance_basic_conformances.swift --check-prefix=TYPEBYNAME
+// RUN: %target-swift-frontend -target x86_64-apple-macosx10.99 -emit-ir %S/../Inputs/conditional_conformance_basic_conformances.swift | %FileCheck %S/../Inputs/conditional_conformance_basic_conformances.swift --check-prefix=TYPEBYNAME_PRESPECIALIZED
 
 // Too many pointer-sized integers in the IR
 // REQUIRES: PTRSIZE=64

test/IRGen/dynamic_self_metadata.swift

@@ -1,5 +1,6 @@
-// RUN: %target-swift-frontend %s -emit-ir -parse-as-library | %FileCheck %s
+// RUN: %target-swift-frontend -disable-generic-metadata-prespecialization %s -emit-ir -parse-as-library | %FileCheck %s
 
+// UNSUPPORTED: OS=windows-msvc
 // REQUIRES: CPU=x86_64
 
 // FIXME: Not a SIL test because we can't parse dynamic Self in SIL.

test/IRGen/dynamic_self_metadata_future.swift

@@ -0,0 +1,79 @@
+// RUN: %target-swift-frontend %s -target %module-target-future -emit-ir -parse-as-library | %FileCheck %s -DINT=i%target-ptrsize -DALIGNMENT=%target-alignment
+
+
+// REQUIRES: OS=macosx || OS=ios || OS=tvos || OS=watchos || OS=linux-gnu
+// REQUIRES: CPU=x86_64
+
+// FIXME: Not a SIL test because we can't parse dynamic Self in SIL.
+// <rdar://problem/16931299>
+
+// CHECK: [[TYPE:%.+]] = type <{ [8 x i8] }>
+
+@inline(never) func id<T>(_ t: T) -> T {
+  return t
+}
+// CHECK-LABEL: define hidden swiftcc void @"$s28dynamic_self_metadata_future2idyxxlF"
+
+protocol P {
+  associatedtype T
+}
+
+extension P {
+  func f() {}
+}
+
+struct G<T> : P {
+  var t: T
+}
+
+class C {
+  class func fromMetatype() -> Self? { return nil }
+  // CHECK-LABEL: define hidden swiftcc i64 @"$s28dynamic_self_metadata_future1CC12fromMetatypeACXDSgyFZ"(%swift.type* swiftself)
+  // CHECK: ret i64 0
+
+  func fromInstance() -> Self? { return nil }
+  // CHECK-LABEL: define hidden swiftcc i64 @"$s28dynamic_self_metadata_future1CC12fromInstanceACXDSgyF"(%T28dynamic_self_metadata_future1CC* swiftself)
+  // CHECK: ret i64 0
+
+  func dynamicSelfArgument() -> Self? {
+    return id(nil)
+  }
+  // CHECK-LABEL: define hidden swiftcc i64 @"$s28dynamic_self_metadata_future1CC0A12SelfArgumentACXDSgyF"(%T28dynamic_self_metadata_future1CC* swiftself)
+  // CHECK: [[GEP1:%.+]] = getelementptr {{.*}} %0
+  // CHECK: [[TYPE1:%.+]] = load {{.*}} [[GEP1]]
+  // CHECK: [[T0:%.+]] = call swiftcc %swift.metadata_response @"$sSqMa"(i64 0, %swift.type* [[TYPE1]])
+  // CHECK: [[TYPE2:%.+]] = extractvalue %swift.metadata_response [[T0]], 0
+  // CHECK: call swiftcc void @"$s28dynamic_self_metadata_future2idyxxlF"({{.*}}, %swift.type* [[TYPE2]])
+
+  func dynamicSelfConformingType() -> Self? {
+    _ = G(t: self).f()
+    return nil
+  }
+  // CHECK-LABEL: define hidden swiftcc i64 @"$s28dynamic_self_metadata_future1CC0A18SelfConformingTypeACXDSgyF"(%T28dynamic_self_metadata_future1CC* swiftself)
+  // CHECK: [[SELF_GEP:%.+]] = getelementptr {{.*}} %0
+  // CHECK: [[SELF_TYPE:%.+]] = load {{.*}} [[SELF_GEP]]
+  // CHECK: call i8** @swift_getWitnessTable(
+  // CHECK-SAME:   %swift.protocol_conformance_descriptor* bitcast (
+  // CHECK-SAME:     {{.*}} @"$s28dynamic_self_metadata_future1GVyxGAA1PAAMc" 
+  // CHECK-SAME:     to %swift.protocol_conformance_descriptor*
+  // CHECK-SAME:   ), 
+  // CHECK-SAME:   %swift.type* getelementptr inbounds (
+  // CHECK-SAME:     %swift.full_type, 
+  // CHECK-SAME:     %swift.full_type* bitcast (
+  // CHECK-SAME:       <{ 
+  // CHECK-SAME:         i8**, 
+  // CHECK-SAME:         [[INT]], 
+  // CHECK-SAME:         %swift.type_descriptor*, 
+  // CHECK-SAME:         %swift.type*, 
+  // CHECK-SAME:         i32, 
+  // CHECK-SAME:         {{(\[4 x i8\])?}}, 
+  // CHECK-SAME:         i64 
+  // CHECK-SAME:       }>* @"$s28dynamic_self_metadata_future1GVyAA1CCXDGMf" 
+  // CHECK-SAME:       to %swift.full_type*
+  // CHECK-SAME:     ), 
+  // CHECK-SAME:     i32 0, 
+  // CHECK-SAME:     i32 1
+  // CHECK-SAME:   ), 
+  // CHECK-SAME:   i8*** undef
+  // CHECK-SAME: )
+}

test/IRGen/foreign_types.sil

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -I %S/Inputs/abi %s -emit-ir | %FileCheck %s -DINT=i%target-ptrsize
+// RUN: %target-swift-frontend -disable-generic-metadata-prespecialization -I %S/Inputs/abi %s -emit-ir | %FileCheck %s -DINT=i%target-ptrsize
 
 sil_stage canonical
 import c_layout

test/IRGen/foreign_types_future.sil

@@ -0,0 +1,44 @@
+// RUN: %target-swift-frontend -target %module-target-future -I %S/Inputs/abi %s -emit-ir | %FileCheck %s -DINT=i%target-ptrsize
+
+// REQUIRES: OS=macosx || OS=ios || OS=tvos || OS=watchos || OS=linux-gnu
+// UNSUPPORTED: CPU=i386 && OS=ios
+// UNSUPPORTED: CPU=armv7 && OS=ios
+// UNSUPPORTED: CPU=armv7s && OS=ios
+
+sil_stage canonical
+import c_layout
+
+// CHECK: [[AMAZING_COLOR_NAME:@.*]] = private constant [13 x i8] c"AmazingColor\00"
+
+// CHECK-LABEL: @"$sSo12AmazingColorVMn" = linkonce_odr hidden constant
+// CHECK-SAME: [[AMAZING_COLOR_NAME]]
+// CHECK-SAME: @"$sSo12AmazingColorVMa"
+
+// CHECK: [[HAS_NESTED_UNION_NAME:@.*]] = private constant [15 x i8] c"HasNestedUnion\00"
+
+// CHECK-LABEL: @"$sSo14HasNestedUnionVMn" = linkonce_odr hidden constant
+// CHECK-SAME: [[HAS_NESTED_UNION_NAME]]
+// CHECK-SAME: @"$sSo14HasNestedUnionVMa"
+
+// CHECK-LABEL: @"$sSo14HasNestedUnionV18__Unnamed_struct_sVMf" = linkonce_odr hidden constant
+// CHECK-SAME:  @"$sSo14HasNestedUnionV18__Unnamed_struct_sVWV"
+// CHECK-SAME:  [[INT]] 512,
+// CHECK-SAME:  @"$sSo14HasNestedUnionV18__Unnamed_struct_sVMn"
+// CHECK-SAME:  i32 0,
+// CHECK-SAME:  i32 4, 
+// CHECK-SAME:  i64 0 }
+
+// CHECK-LABEL: @"\01l_type_metadata_table" = private constant
+// CHECK-SAME: @"$sSo12AmazingColorVMn"
+// CHECK-SAME: @"$sSo14HasNestedUnionVMn"
+// CHECK-SAME: @"$sSo14HasNestedUnionV18__Unnamed_struct_sVMn"
+
+sil @test0 : $() -> () {
+bb0:
+  %0 = metatype $@thick HasNestedUnion.Type
+  %1 = metatype $@thick AmazingColor.Type
+
+  %ret = tuple ()
+  return %ret : $()
+}
+