[embedded] Stop emitting metadata for extensions

Author: kubamracek

lib/IRGen/GenDecl.cpp

@@ -5678,6 +5678,10 @@ static bool shouldEmitCategory(IRGenModule &IGM, ExtensionDecl *ext) {
 void IRGenModule::emitExtension(ExtensionDecl *ext) {
   emitNestedTypeDecls(ext->getMembers());
 
+  if (ext->getASTContext().LangOpts.hasFeature(Feature::Embedded)) {
+    return;
+  }
+
   addLazyConformances(ext);
 
   // Generate a category if the extension either introduces a

lib/IRGen/IRGenModule.cpp

@@ -1295,6 +1295,8 @@ bool IRGenerator::canEmitWitnessTableLazily(SILWitnessTable *wt) {
 }
 
 void IRGenerator::addLazyWitnessTable(const ProtocolConformance *Conf) {
+  assert(!SIL.getASTContext().LangOpts.hasFeature(Feature::Embedded));
+
   if (auto *wt = SIL.lookUpWitnessTable(Conf)) {
     // Add it to the queue if it hasn't already been put there.
     if (canEmitWitnessTableLazily(wt) &&

test/embedded/extensions.swift

@@ -0,0 +1,23 @@
+// RUN: %empty-directory(%t)
+// RUN: %{python} %utils/split_file.py -o %t %s
+
+// RUN: %target-swift-frontend -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift -parse-stdlib -enable-experimental-feature Embedded
+// RUN: %target-swift-frontend -emit-ir     -I %t                      %t/Main.swift     -parse-stdlib -enable-experimental-feature Embedded | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
+
+// BEGIN MyModule.swift
+
+public protocol MyProtocol {}
+
+// BEGIN Main.swift
+
+import MyModule
+
+struct MyStruct {}
+
+extension MyStruct: MyProtocol {}
+
+// CHECK: define {{.*}}i32 @main(i32 %0, ptr %1)
+// CHECK-NOT: MyStruct
+// CHECK-NOT: MyProtocol