SILGen/stdlib: Remove _diagnoseUnavailableCodeReached_aeic().

It should no longer be necessary to provide an `@_alwaysEmitIntoClient` version
of `_diagnoseUnavailableCodeReached()`. This workaround was originally added to
provide compatibility with projects that were misconfigured to compile against
a newer stdlib but link against an older one.

Resolves rdar://119892482.

Author: tshortli

include/swift/AST/ASTContext.h

@@ -1499,10 +1499,6 @@ class ASTContext final {
   /// The declared interface type of Builtin.TheTupleType.
   BuiltinTupleType *getBuiltinTupleType();
 
-  /// The declaration for the `_diagnoseUnavailableCodeReached()` declaration
-  /// that ought to be used for the configured deployment target.
-  FuncDecl *getDiagnoseUnavailableCodeReachedDecl();
-
   Type getNamedSwiftType(ModuleDecl *module, StringRef name);
 
   /// Set the plugin loader.

include/swift/AST/KnownDecls.def

@@ -73,7 +73,6 @@ FUNC_DECL(DiagnoseUnexpectedNilOptional, "_diagnoseUnexpectedNilOptional")
 FUNC_DECL(DiagnoseUnexpectedEnumCase, "_diagnoseUnexpectedEnumCase")
 FUNC_DECL(DiagnoseUnexpectedEnumCaseValue, "_diagnoseUnexpectedEnumCaseValue")
 FUNC_DECL(DiagnoseUnavailableCodeReached, "_diagnoseUnavailableCodeReached")
-FUNC_DECL(DiagnoseUnavailableCodeReachedAEIC, "_diagnoseUnavailableCodeReached_aeic")
 
 FUNC_DECL(GetErrorEmbeddedNSError, "_getErrorEmbeddedNSError")
 

lib/AST/ASTContext.cpp

@@ -6591,14 +6591,6 @@ BuiltinTupleType *ASTContext::getBuiltinTupleType() {
   return result;
 }
 
-FuncDecl *ASTContext::getDiagnoseUnavailableCodeReachedDecl() {
-  // FIXME: Remove this with rdar://119892482
-  if (AvailabilityContext::forDeploymentTarget(*this).isContainedIn(
-      getSwift59Availability()))
-    return getDiagnoseUnavailableCodeReached();
-  return getDiagnoseUnavailableCodeReachedAEIC();
-}
-
 void ASTContext::setPluginLoader(std::unique_ptr<PluginLoader> loader) {
   getImpl().Plugins = std::move(loader);
 }

lib/SILGen/SILGenApply.cpp

@@ -6397,7 +6397,7 @@ void SILGenFunction::emitApplyOfUnavailableCodeReached() {
     return;
 
   auto loc = RegularLocation::getAutoGeneratedLocation(F.getLocation());
-  FuncDecl *fd = getASTContext().getDiagnoseUnavailableCodeReachedDecl();
+  FuncDecl *fd = getASTContext().getDiagnoseUnavailableCodeReached();
 
   if (!fd) {
     // Broken stdlib?

lib/Sema/DerivedConformances.cpp

@@ -498,7 +498,7 @@ DerivedConformance::createBuiltinCall(ASTContext &ctx,
 
 CallExpr *DerivedConformance::createDiagnoseUnavailableCodeReachedCallExpr(
     ASTContext &ctx) {
-  FuncDecl *diagnoseDecl = ctx.getDiagnoseUnavailableCodeReachedDecl();
+  FuncDecl *diagnoseDecl = ctx.getDiagnoseUnavailableCodeReached();
   assert(diagnoseDecl);
   auto diagnoseDeclRefExpr =
       new (ctx) DeclRefExpr(diagnoseDecl, DeclNameLoc(), true);
@@ -936,7 +936,7 @@ CaseStmt *DerivedConformance::unavailableEnumElementCaseStmt(
   // If the stdlib isn't new enough to contain the helper function for
   // diagnosing execution of unavailable code then just synthesize this case
   // normally.
-  if (!C.getDiagnoseUnavailableCodeReachedDecl())
+  if (!C.getDiagnoseUnavailableCodeReached())
     return nullptr;
 
   auto createElementPattern = [&]() -> EnumElementPattern * {

stdlib/public/core/AssertCommon.swift

@@ -338,17 +338,6 @@ internal func _diagnoseUnexpectedEnumCase<SwitchedValue>(
 @_semantics("unavailable_code_reached")
 @usableFromInline // COMPILER_INTRINSIC
 internal func _diagnoseUnavailableCodeReached() -> Never {
-  _diagnoseUnavailableCodeReached_aeic()
-}
-
-// FIXME: Remove this with rdar://119892482
-/// An `@_alwaysEmitIntoClient` variant of `_diagnoseUnavailableCodeReached()`.
-/// This is temporarily needed by the compiler to reference from back deployed
-/// clients.
-@_alwaysEmitIntoClient
-@inline(never)
-@_semantics("unavailable_code_reached")
-internal func _diagnoseUnavailableCodeReached_aeic() -> Never {
   _assertionFailure(
     "Fatal error", "Unavailable code reached", flags: _fatalErrorFlags())
 }

test/SILGen/unavailable_decl_optimization_stub.swift

@@ -3,7 +3,7 @@
 public struct S {}
 
 // CHECK-LABEL: sil{{.*}}@$s4Test15unavailableFuncAA1SVyF
-// CHECK:         [[FNREF:%.*]] = function_ref @$[[DIAGNOSEFN:(ss36_diagnoseUnavailableCodeReached_aeics5NeverOyF|ss31_diagnoseUnavailableCodeReacheds5NeverOyF|ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb)]] : $@convention(thin) () -> Never
+// CHECK:         [[FNREF:%.*]] = function_ref @$[[DIAGNOSEFN:(ss31_diagnoseUnavailableCodeReacheds5NeverOyF|ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb)]] : $@convention(thin) () -> Never
 // CHECK-NEXT:    [[APPLY:%.*]] = apply [[FNREF]]()
 // CHECK:         function_ref @$s4Test1SVACycfC
 // CHECK:       } // end sil function '$s4Test15unavailableFuncAA1SVyF'

test/SILGen/unavailable_decl_optimization_stub_class.swift

@@ -7,7 +7,7 @@ func foo() {}
 public class ExplicitInitClass {
   // ExplicitInitClass.s.getter
   // CHECK-LABEL: sil{{.*}}@$s4Test17ExplicitInitClassC1sAA1SVvg
-  // CHECK:         [[FNREF:%.*]] = function_ref @$[[DIAGNOSEFN:(ss36_diagnoseUnavailableCodeReached_aeics5NeverOyF|ss31_diagnoseUnavailableCodeReacheds5NeverOyF|ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb)]] : $@convention(thin) () -> Never
+  // CHECK:         [[FNREF:%.*]] = function_ref @$[[DIAGNOSEFN:(ss31_diagnoseUnavailableCodeReacheds5NeverOyF|ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb)]] : $@convention(thin) () -> Never
   // CHECK-NEXT:    [[APPLY:%.*]] = apply [[FNREF]]()
   // CHECK:         load
   // CHECK:       } // end sil function '$s4Test17ExplicitInitClassC1sAA1SVvg'

test/SILGen/unavailable_decl_optimization_stub_macos.swift

@@ -6,23 +6,23 @@
 // REQUIRES: OS=macosx
 
 // CHECK-LABEL:     sil{{.*}}@$s4Test15unavailableFuncyyF
-// CHECK-SWIFT5_8:    [[FNREF:%.*]] = function_ref @$ss36_diagnoseUnavailableCodeReached_aeics5NeverOyF : $@convention(thin) () -> Never
+// CHECK-SWIFT5_8:    [[FNREF:%.*]] = function_ref @$ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb : $@convention(thin) () -> Never
 // CHECK-SWIFT5_9:    [[FNREF:%.*]] = function_ref @$ss31_diagnoseUnavailableCodeReacheds5NeverOyF : $@convention(thin) () -> Never
 // CHECK-NEXT:        [[APPLY:%.*]] = apply [[FNREF]]()
 // CHECK:           } // end sil function '$s4Test15unavailableFuncyyF'
 @available(*, unavailable)
 public func unavailableFunc() {}
 
 // CHECK-LABEL:     sil{{.*}}@$s4Test24unavailableInlinableFuncyyF
-// CHECK-SWIFT5_8:    [[FNREF:%.*]] = function_ref @$ss36_diagnoseUnavailableCodeReached_aeics5NeverOyF : $@convention(thin) () -> Never
+// CHECK-SWIFT5_8:    [[FNREF:%.*]] = function_ref @$ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb : $@convention(thin) () -> Never
 // CHECK-SWIFT5_9:    [[FNREF:%.*]] = function_ref @$ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb : $@convention(thin) () -> Never
 // CHECK-NEXT:        [[APPLY:%.*]] = apply [[FNREF]]()
 // CHECK:           } // end sil function '$s4Test24unavailableInlinableFuncyyF'
 @available(*, unavailable)
 @inlinable public func unavailableInlinableFunc() {}
 
 // CHECK-LABEL:     sil{{.*}}@$s4Test22unavailableOnMacOSFuncyyF
-// CHECK-SWIFT5_8:    [[FNREF:%.*]] = function_ref @$ss36_diagnoseUnavailableCodeReached_aeics5NeverOyF : $@convention(thin) () -> Never
+// CHECK-SWIFT5_8:    [[FNREF:%.*]] = function_ref @$ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb : $@convention(thin) () -> Never
 // CHECK-SWIFT5_9:    [[FNREF:%.*]] = function_ref @$ss31_diagnoseUnavailableCodeReacheds5NeverOyF : $@convention(thin) () -> Never
 // CHECK-NEXT:        [[APPLY:%.*]] = apply [[FNREF]]()
 // CHECK:           } // end sil function '$s4Test22unavailableOnMacOSFuncyyF'
@@ -36,7 +36,7 @@ public func unavailableOnMacOSFunc() {}
 public func unavailableOnMacOSExtensionFunc() {}
 
 // CHECK-LABEL:     sil{{.*}}@$s4Test021unavailableOnMacOSAndD15OSExtensionFuncyyF
-// CHECK-SWIFT5_8:    [[FNREF:%.*]] = function_ref @$ss36_diagnoseUnavailableCodeReached_aeics5NeverOyF : $@convention(thin) () -> Never
+// CHECK-SWIFT5_8:    [[FNREF:%.*]] = function_ref @$ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb : $@convention(thin) () -> Never
 // CHECK-SWIFT5_9:    [[FNREF:%.*]] = function_ref @$ss31_diagnoseUnavailableCodeReacheds5NeverOyF : $@convention(thin) () -> Never
 // CHECK-NEXT:        [[APPLY:%.*]] = apply [[FNREF]]()
 // CHECK:           } // end sil function '$s4Test021unavailableOnMacOSAndD15OSExtensionFuncyyF'

test/SILGen/unavailable_decl_optimization_stub_macos_zippered.swift

@@ -3,7 +3,7 @@
 // REQUIRES: OS=macosx
 
 // CHECK-LABEL:     sil{{.*}}@$s4Test15unavailableFuncyyF
-// CHECK:             [[FNREF:%.*]] = function_ref @$ss36_diagnoseUnavailableCodeReached_aeics5NeverOyF : $@convention(thin) () -> Never
+// CHECK:             [[FNREF:%.*]] = function_ref @$ss31_diagnoseUnavailableCodeReacheds5NeverOyFTwb : $@convention(thin) () -> Never
 // CHECK-NEXT:        [[APPLY:%.*]] = apply [[FNREF]]()
 // CHECK:           } // end sil function '$s4Test15unavailableFuncyyF'
 @available(*, unavailable)