SIL: remove the private_external SILLinkage

include/swift/SIL/SILLinkage.h

@@ -85,11 +85,6 @@ enum class SILLinkage : uint8_t {
   /// shared.
   SharedExternal,
 
-  /// The same as SharedExternal, except that the definition is private in the
-  /// other module. This can only occur if an inlined fragile function from
-  /// another module references a private definition in the other module.
-  PrivateExternal,
-
   /// The default linkage for a definition.
   DefaultForDefinition = Public,
 
@@ -138,8 +133,6 @@ inline SILLinkage stripExternalFromLinkage(SILLinkage linkage) {
     return SILLinkage::Hidden;
   if (linkage == SILLinkage::SharedExternal)
     return SILLinkage::Shared;
-  if (linkage == SILLinkage::PrivateExternal)
-    return SILLinkage::Private;
   return linkage;
 }
 
@@ -158,10 +151,8 @@ inline SILLinkage addExternalToLinkage(SILLinkage linkage) {
   case SILLinkage::Hidden:
     return SILLinkage::HiddenExternal;
   case SILLinkage::Private:
-    return SILLinkage::PrivateExternal;
   case SILLinkage::PublicExternal:
   case SILLinkage::SharedExternal:
-  case SILLinkage::PrivateExternal:
   case SILLinkage::HiddenExternal:
     return linkage;
   }
@@ -197,7 +188,6 @@ inline bool hasPublicVisibility(SILLinkage linkage) {
   case SILLinkage::Shared:
   case SILLinkage::SharedExternal:
   case SILLinkage::Private:
-  case SILLinkage::PrivateExternal:
   case SILLinkage::HiddenExternal:
     return false;
   }
@@ -216,7 +206,6 @@ inline bool hasSharedVisibility(SILLinkage linkage) {
   case SILLinkage::Hidden:
   case SILLinkage::HiddenExternal:
   case SILLinkage::Private:
-  case SILLinkage::PrivateExternal:
     return false;
   }
 
@@ -226,7 +215,6 @@ inline bool hasSharedVisibility(SILLinkage linkage) {
 inline bool hasPrivateVisibility(SILLinkage linkage) {
   switch (linkage) {
   case SILLinkage::Private:
-  case SILLinkage::PrivateExternal:
     return true;
   case SILLinkage::Public:
   case SILLinkage::PublicExternal:
@@ -247,8 +235,7 @@ inline SILLinkage effectiveLinkageForClassMember(SILLinkage linkage,
   case SubclassScope::External:
     if (linkage == SILLinkage::Private || linkage == SILLinkage::Hidden)
       return SILLinkage::Public;
-    if (linkage == SILLinkage::PrivateExternal ||
-        linkage == SILLinkage::HiddenExternal)
+    if (linkage == SILLinkage::HiddenExternal)
       return SILLinkage::PublicExternal;
     break;
 

include/swift/SIL/SILWitnessTable.h

@@ -48,7 +48,8 @@ class SILWitnessTable : public llvm::ilist_node<SILWitnessTable>,
     /// The method required.
     SILDeclRef Requirement;
     /// The witness for the method.
-    /// This can be null in case dead function elimination has removed the method.
+    /// This can be null in case dead function elimination has removed the method
+    /// or if the method was not serialized (for de-serialized witness tables).
     SILFunction *Witness;
   };
 

lib/IRGen/GenDecl.cpp

@@ -2074,7 +2074,6 @@ getIRLinkage(const UniversalLinkageInfo &info, SILLinkage linkage,
   }
 
   case SILLinkage::HiddenExternal:
-  case SILLinkage::PrivateExternal:
     if (isDefinition)
       return RESULT(AvailableExternally, Hidden, Default);
 

lib/IRGen/GenMeta.cpp

@@ -2023,7 +2023,6 @@ namespace {
       case SILLinkage::Hidden:
       case SILLinkage::HiddenExternal:
       case SILLinkage::Private:
-      case SILLinkage::PrivateExternal:
         return true;
 
       case SILLinkage::Shared:

lib/IRGen/Linking.cpp

@@ -609,7 +609,8 @@ SILLinkage LinkEntity::getLinkage(ForDefinition_t forDefinition) const {
     auto *nominal = getType().getAnyNominal();
     if (getDeclLinkage(nominal) == FormalLinkage::PublicNonUnique)
       return SILLinkage::Shared;
-    return forDefinition ? SILLinkage::Private : SILLinkage::PrivateExternal;
+    assert(forDefinition);
+    return SILLinkage::Private;
   }
 
   case Kind::TypeMetadataAccessFunction:

lib/SIL/IR/SIL.cpp

@@ -86,7 +86,7 @@ swift::getLinkageForProtocolConformance(const RootProtocolConformance *C,
   switch (access) {
     case AccessLevel::Private:
     case AccessLevel::FilePrivate:
-      return (definition ? SILLinkage::Private : SILLinkage::PrivateExternal);
+      return SILLinkage::Private;
 
     case AccessLevel::Internal:
       return (definition ? SILLinkage::Hidden : SILLinkage::HiddenExternal);
@@ -280,7 +280,6 @@ bool AbstractStorageDecl::exportsPropertyDescriptor() const {
     return false;
 
   case SILLinkage::HiddenExternal:
-  case SILLinkage::PrivateExternal:
   case SILLinkage::PublicExternal:
   case SILLinkage::SharedExternal:
     llvm_unreachable("should be definition linkage?");

lib/SIL/IR/SILDeclRef.cpp

@@ -412,7 +412,7 @@ SILLinkage SILDeclRef::getLinkage(ForDefinition_t forDefinition) const {
   switch (effectiveAccess) {
   case AccessLevel::Private:
   case AccessLevel::FilePrivate:
-    return maybeAddExternal(SILLinkage::Private);
+    return SILLinkage::Private;
 
   case AccessLevel::Internal:
     if (limit == Limit::OnDemand)

lib/SIL/IR/SILDefaultWitnessTable.cpp

@@ -90,7 +90,8 @@ convertToDefinition(ArrayRef<Entry> entries) {
   // Bump the reference count of witness functions referenced by this table.
   for (auto entry : getEntries()) {
     if (entry.isValid() && entry.getKind() == SILWitnessTable::Method) {
-      entry.getMethodWitness().Witness->incrementRefCount();
+      if (SILFunction *f = entry.getMethodWitness().Witness)
+        f->incrementRefCount();
     }
   }
 }
@@ -105,7 +106,8 @@ SILDefaultWitnessTable::~SILDefaultWitnessTable() {
   // Drop the reference count of witness functions referenced by this table.
   for (auto entry : getEntries()) {
     if (entry.isValid() && entry.getKind() == SILWitnessTable::Method) {
-      entry.getMethodWitness().Witness->decrementRefCount();
+      if (SILFunction *f = entry.getMethodWitness().Witness)
+        f->decrementRefCount();
     }
   }
 }

lib/SIL/IR/SILModule.cpp

@@ -79,12 +79,10 @@ class SILModule::SerializationCallback final
       decl->setLinkage(SILLinkage::SharedExternal);
       return;
     case SILLinkage::Private:
-      decl->setLinkage(SILLinkage::PrivateExternal);
-      return;
+      llvm_unreachable("cannot make a private external symbol");
     case SILLinkage::PublicExternal:
     case SILLinkage::HiddenExternal:
     case SILLinkage::SharedExternal:
-    case SILLinkage::PrivateExternal:
       return;
     }
   }

lib/SIL/IR/SILPrinter.cpp

@@ -2746,7 +2746,6 @@ static StringRef getLinkageString(SILLinkage linkage) {
   case SILLinkage::PublicExternal: return "public_external ";
   case SILLinkage::HiddenExternal: return "hidden_external ";
   case SILLinkage::SharedExternal: return "shared_external ";
-  case SILLinkage::PrivateExternal: return "private_external ";
   }
   llvm_unreachable("bad linkage");
 }

lib/SIL/Parser/ParseSIL.cpp

@@ -779,7 +779,6 @@ static bool parseSILLinkage(Optional<SILLinkage> &Result, Parser &P) {
     .Case("public_external", SILLinkage::PublicExternal)
     .Case("hidden_external", SILLinkage::HiddenExternal)
     .Case("shared_external", SILLinkage::SharedExternal)
-    .Case("private_external", SILLinkage::PrivateExternal)
     .Default(None);
 
   // If we succeed, consume the token.

lib/SIL/Verifier/SILVerifier.cpp

@@ -5958,6 +5958,8 @@ void SILDefaultWitnessTable::verify(const SILModule &M) const {
       continue;
 
     SILFunction *F = E.getMethodWitness().Witness;
+    if (!F)
+      continue;
 
 #if 0
     // FIXME: For now, all default witnesses are private.

lib/SILGen/SILGen.cpp

@@ -65,6 +65,26 @@ SILGenModule::SILGenModule(SILModule &M, ModuleDecl *SM)
 
 SILGenModule::~SILGenModule() {
   assert(!TopLevelSGF && "active source file lowering!?");
+
+  // Update the linkage of external private functions to public_external,
+  // because there is no private_external linkage. External private functions
+  // can occur in the following cases:
+  //
+  // * private class methods which are referenced from the vtable of a derived
+  //   class  in a different file/module. Such private methods are always
+  //   generated with public linkage in the other file/module.
+  //
+  // * in lldb: lldb can access private declarations in other files/modules
+  //
+  // * private functions with a @_silgen_name attribute but without a body
+  //
+  // * when compiling with -disable-access-control
+  //
+  for (SILFunction &f : M.getFunctionList()) {
+    if (f.getLinkage() == SILLinkage::Private && f.isExternalDeclaration())
+      f.setLinkage(SILLinkage::PublicExternal);
+  }
+
   M.verify();
 }
 

lib/SILOptimizer/IPO/CrossModuleSerializationSetup.cpp

@@ -404,7 +404,6 @@ bool CrossModuleSerializationSetup::canUseFromInline(SILFunction *func,
   case SILLinkage::Private:
   case SILLinkage::PublicExternal:
   case SILLinkage::SharedExternal:
-  case SILLinkage::PrivateExternal:
   case SILLinkage::HiddenExternal:
     break;
   }

lib/SILOptimizer/UtilityPasses/InstCount.cpp

@@ -50,7 +50,6 @@ STATISTIC(TotalPrivateFuncs, "Number of private funcs");
 STATISTIC(TotalSharedFuncs, "Number of shared funcs");
 STATISTIC(TotalPublicExternalFuncs, "Number of public external funcs");
 STATISTIC(TotalHiddenExternalFuncs, "Number of hidden external funcs");
-STATISTIC(TotalPrivateExternalFuncs, "Number of private external funcs");
 STATISTIC(TotalSharedExternalFuncs, "Number of shared external funcs");
 
 // Individual instruction statistics
@@ -139,9 +138,6 @@ class InstCount : public SILFunctionTransform {
     case SILLinkage::SharedExternal:
       ++TotalSharedExternalFuncs;
       break;
-    case SILLinkage::PrivateExternal:
-      ++TotalPrivateExternalFuncs;
-      break;
     }
   }
 };

lib/Serialization/DeserializeSIL.cpp

@@ -70,7 +70,6 @@ fromStableSILLinkage(unsigned value) {
   case SIL_LINKAGE_PUBLIC_EXTERNAL: return SILLinkage::PublicExternal;
   case SIL_LINKAGE_HIDDEN_EXTERNAL: return SILLinkage::HiddenExternal;
   case SIL_LINKAGE_SHARED_EXTERNAL: return SILLinkage::SharedExternal;
-  case SIL_LINKAGE_PRIVATE_EXTERNAL: return SILLinkage::PrivateExternal;
   default: return None;
   }
 }

lib/Serialization/ModuleFormat.h

@@ -56,7 +56,7 @@ const uint16_t SWIFTMODULE_VERSION_MAJOR = 0;
 /// describe what change you made. The content of this comment isn't important;
 /// it just ensures a conflict if two people change the module format.
 /// Don't worry about adhering to the 80-column limit for this line.
-const uint16_t SWIFTMODULE_VERSION_MINOR = 633; // remove value_buffer insts
+const uint16_t SWIFTMODULE_VERSION_MINOR = 634; // remove PrivateExternal
 
 /// A standard hash seed used for all string hashes in a serialized module.
 ///

lib/Serialization/SILFormat.h

@@ -45,7 +45,6 @@ enum SILLinkageEncoding : uint8_t {
   SIL_LINKAGE_PUBLIC_EXTERNAL,
   SIL_LINKAGE_HIDDEN_EXTERNAL,
   SIL_LINKAGE_SHARED_EXTERNAL,
-  SIL_LINKAGE_PRIVATE_EXTERNAL,
 };
 using SILLinkageField = BCFixed<4>;
 

lib/Serialization/SerializeSIL.cpp

@@ -66,7 +66,6 @@ static unsigned toStableSILLinkage(SILLinkage linkage) {
   case SILLinkage::PublicExternal: return SIL_LINKAGE_PUBLIC_EXTERNAL;
   case SILLinkage::HiddenExternal: return SIL_LINKAGE_HIDDEN_EXTERNAL;
   case SILLinkage::SharedExternal: return SIL_LINKAGE_SHARED_EXTERNAL;
-  case SILLinkage::PrivateExternal: return SIL_LINKAGE_PRIVATE_EXTERNAL;
   }
   llvm_unreachable("bad linkage");
 }
@@ -2666,7 +2665,8 @@ void SILSerializer::writeSILWitnessTableEntry(
   SmallVector<ValueID, 4> ListOfValues;
   handleSILDeclRef(S, methodWitness.Requirement, ListOfValues);
   IdentifierID witnessID = 0;
-  if (SILFunction *witness = methodWitness.Witness) {
+  SILFunction *witness = methodWitness.Witness;
+  if (witness && witness->hasValidLinkageForFragileRef()) {
     addReferencedSILFunction(witness, true);
     witnessID = S.addUniquedStringRef(witness->getName());
   }

test/IRGen/sil_linkage.sil

@@ -15,7 +15,6 @@ sil_stage canonical
 // CHECK: declare{{( dllimport)?}} swiftcc void @public_external_fragile_function_def_test()
 // CHECK: define{{( protected)?}} available_externally{{ (hidden)?}}{{( dllimport)?}} swiftcc void @hidden_external_fragile_function_def_test() {{.*}} {
 // CHECK: define linkonce_odr hidden swiftcc void @shared_external_fragile_function_def_test() {{.*}} {
-// CHECK: define{{( protected)?}} available_externally{{ (hidden)?}}{{( dllimport)?}} swiftcc void @private_external_fragile_function_def_test() {{.*}} {
 // CHECK: define{{( protected)?}}{{( dllexport)?}} swiftcc void @public_resilient_function_test() {{.*}} {
 // CHECK: define hidden swiftcc void @hidden_resilient_function_test() {{.*}} {
 // CHECK: define linkonce_odr hidden swiftcc void @shared_resilient_function_test() {{.*}} {
@@ -75,11 +74,6 @@ sil shared_external [serialized] @shared_external_fragile_function_def_test : $@
   return %0 : $()
 }
 
-sil private_external [serialized] @private_external_fragile_function_def_test : $@convention(thin) () -> () {
-  %0 = tuple()
-  return %0 : $()
-}
-
 sil public_external [serialized] @public_external_fragile_function_decl_test : $@convention(thin) () -> ()
 
 sil hidden_external [serialized] @hidden_external_fragile_function_decl_test : $@convention(thin) () -> ()
@@ -153,7 +147,6 @@ sil public @use_all_symbols : $@convention(thin) () -> () {
   %4 = function_ref @public_external_fragile_function_def_test : $@convention(thin) () -> ()
   %5 = function_ref @hidden_external_fragile_function_def_test : $@convention(thin) () -> ()
   %6 = function_ref @shared_external_fragile_function_def_test : $@convention(thin) () -> ()
-  %7 = function_ref @private_external_fragile_function_def_test : $@convention(thin) () -> ()
   %8 = function_ref @public_external_fragile_function_decl_test : $@convention(thin) () -> ()
   %9 = function_ref @hidden_external_fragile_function_decl_test : $@convention(thin) () -> ()
   // %10 = function_ref @shared_external_fragile_function_decl_test : $@convention(thin) () -> ()
@@ -178,7 +171,6 @@ sil public @use_all_symbols : $@convention(thin) () -> () {
   apply %4() : $@convention(thin) () -> ()
   apply %5() : $@convention(thin) () -> ()
   apply %6() : $@convention(thin) () -> ()
-  apply %7() : $@convention(thin) () -> ()
   apply %8() : $@convention(thin) () -> ()
   apply %9() : $@convention(thin) () -> ()
   // apply %10() : $@convention(thin) () -> ()

test/SILOptimizer/devirt_try_apply.sil

@@ -70,7 +70,7 @@ public func test6() -> Int32?
 sil_global [serialized] @_TZvOs7Process5_argcVs5Int32 : $Int32
 
 
-sil_global private_external [serialized] @globalinit_33_1BDF70FFC18749BAB495A73B459ED2F0_token5 : $Builtin.Word
+sil_global [serialized] @globalinit_33_1BDF70FFC18749BAB495A73B459ED2F0_token5 : $Builtin.Word
 
 
 sil_global [serialized] @_TZvOs7Process11_unsafeArgvGVs20UnsafeMutablePointerGS0_Vs4Int8__ : $UnsafeMutablePointer<UnsafeMutablePointer<Int8>>
@@ -780,7 +780,7 @@ bb4(%19 : $Error):
 }
 
 
-sil private_external [serialized] @globalinit_33_1BDF70FFC18749BAB495A73B459ED2F0_func5 : $@convention(thin) () -> ()
+sil [serialized] @globalinit_33_1BDF70FFC18749BAB495A73B459ED2F0_func5 : $@convention(thin) () -> ()
 
 
 public class A {

test/SILOptimizer/devirt_try_apply_ownership.sil

@@ -69,7 +69,7 @@ public func test6() -> Int32?
 sil_global [serialized] @_TZvOs7Process5_argcVs5Int32 : $Int32
 
 
-sil_global private_external [serialized] @globalinit_33_1BDF70FFC18749BAB495A73B459ED2F0_token5 : $Builtin.Word
+sil_global [serialized] @globalinit_33_1BDF70FFC18749BAB495A73B459ED2F0_token5 : $Builtin.Word
 
 
 sil_global [serialized] @_TZvOs7Process11_unsafeArgvGVs20UnsafeMutablePointerGS0_Vs4Int8__ : $UnsafeMutablePointer<UnsafeMutablePointer<Int8>>
@@ -736,7 +736,7 @@ bb4(%19 : @owned $Error):
 }
 
 
-sil private_external [serialized] [ossa] @globalinit_33_1BDF70FFC18749BAB495A73B459ED2F0_func5 : $@convention(thin) () -> ()
+sil [serialized] [ossa] @globalinit_33_1BDF70FFC18749BAB495A73B459ED2F0_func5 : $@convention(thin) () -> ()
 
 
 public class A {

test/SILOptimizer/optimize_never.sil

@@ -75,7 +75,7 @@ public func boo4(c: C) -> Int32
 sil_global [serialized] @$ss7ProcessO5_argcs5Int32VvZ : $Int32
 
 
-sil_global private_external [serialized] @globalinit_33_1BDF70FFC18749BAB495A73B459ED2F0_token5 : $Builtin.Word
+sil_global [serialized] @globalinit_33_1BDF70FFC18749BAB495A73B459ED2F0_token5 : $Builtin.Word
 
 
 sil_global [serialized] @$ss7ProcessO11_unsafeArgvSpySpys4Int8VGGvZ : $UnsafeMutablePointer<UnsafeMutablePointer<Int8>>