Just autolink every imported module, public or private

This is unfortunate in that it makes the linker do extra work, but in
practice it probably doesn't matter much, and meanwhile it handles all
our problems with @inlinable.

Alternate solution to rdar://problem/39338239

Author: jrose-apple

lib/AST/Module.cpp

@@ -1214,13 +1214,15 @@ void ModuleDecl::collectLinkLibraries(LinkLibraryCallback callback) {
 
 void
 SourceFile::collectLinkLibraries(ModuleDecl::LinkLibraryCallback callback) const {
-
-  const_cast<SourceFile *>(this)->forAllVisibleModules([&](swift::ModuleDecl::ImportedModule import) {
+  forAllImportedModules<false>(getParentModule(), /*thisPath*/{},
+                               /*includePrivateTopLevelImports*/false,
+                               [=](ModuleDecl::ImportedModule import) -> bool {
     swift::ModuleDecl *next = import.second;
     if (next->getName() == getParentModule()->getName())
-      return;
+      return true;
 
     next->collectLinkLibraries(callback);
+    return true;
   });
 }
 

test/ClangImporter/autolinking.swift

@@ -7,7 +7,9 @@
 // RUN: %FileCheck %s < %t/with-adapter.ll
 // RUN: %FileCheck -check-prefix CHECK-WITH-SWIFT %s < %t/with-adapter.ll
 
-// RUN: %target-swift-frontend %s -sdk %S/Inputs -I %S/Inputs/custom-modules -emit-ir -disable-autolink-framework LinkFramework -o - | %FileCheck -check-prefix CHECK-WITH-DISABLED %s
+// RUN: %target-swift-frontend %s -sdk %S/Inputs -I %S/Inputs/custom-modules -emit-ir -disable-autolink-framework LinkFramework -o - > %t/with-disabled.ll
+// RUN: %FileCheck -check-prefix CHECK-WITH-DISABLED %s < %t/with-disabled.ll
+// RUN: %FileCheck -check-prefix NEGATIVE-WITH-DISABLED %s < %t/with-disabled.ll
 
 // Linux uses a different autolinking mechanism, based on
 // swift-autolink-extract. This file tests the Darwin mechanism.
@@ -37,6 +39,6 @@ UsesSubmodule.useSomethingFromSubmodule()
 
 // CHECK-WITH-SWIFT: !{{[0-9]+}} = !{!"-lSwiftAdapter"}
 
-// CHECK-WITH-DISABLED: !{!"-framework", !"Barrel"}
-// CHECK-WITH-DISABLED-NOT: !{!"-framework", !"LinkFramework"}
-// CHECK-WITH-DISABLED: !{!"-framework", !"Indirect"}
+// CHECK-WITH-DISABLED-DAG: !{!"-framework", !"Barrel"}
+// CHECK-WITH-DISABLED-DAG: !{!"-framework", !"Indirect"}
+// NEGATIVE-WITH-DISABLED-NOT: !"LinkFramework"

test/Serialization/Inputs/autolinking_indirect.swift

@@ -0,0 +1 @@
+@_exported import autolinking_other2

test/Serialization/Inputs/autolinking_module_inferred.swift

@@ -0,0 +1,8 @@
+@_exported import autolinking_public
+import autolinking_other
+import autolinking_indirect
+import autolinking_private
+
+public func bfunc(x: Int = afunc(), y: Int = afunc2()) {
+  cfunc()
+}

test/Serialization/Inputs/autolinking_other.swift

@@ -0,0 +1 @@
+public func afunc() -> Int { return 0 }

test/Serialization/Inputs/autolinking_other2.swift

@@ -0,0 +1 @@
+public func afunc2() -> Int { return 0 }

test/Serialization/Inputs/autolinking_private.swift

@@ -0,0 +1 @@
+public func cfunc() {}

test/Serialization/Inputs/autolinking_public.swift

@@ -0,0 +1 @@
+// Empty module

test/Serialization/autolinking-inlinable-inferred.swift

@@ -0,0 +1,36 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend -emit-module %S/Inputs/autolinking_public.swift -emit-module-path %t/autolinking_public.swiftmodule -module-link-name autolinking_public -swift-version 4
+// RUN: %target-swift-frontend -emit-module %S/Inputs/autolinking_other.swift -emit-module-path %t/autolinking_other.swiftmodule -module-link-name autolinking_other -swift-version 4
+// RUN: %target-swift-frontend -emit-module %S/Inputs/autolinking_private.swift -emit-module-path %t/autolinking_private.swiftmodule -module-link-name autolinking_private -I %t -swift-version 4
+// RUN: %target-swift-frontend -emit-module %S/Inputs/autolinking_other2.swift -emit-module-path %t/autolinking_other2.swiftmodule -module-link-name autolinking_other2 -swift-version 4
+// RUN: %target-swift-frontend -emit-module %S/Inputs/autolinking_indirect.swift -emit-module-path %t/autolinking_indirect.swiftmodule -module-link-name autolinking_indirect -I %t -swift-version 4
+
+// RUN: %target-swift-frontend -emit-module %S/Inputs/autolinking_module_inferred.swift -emit-module-path %t/autolinking_module_inferred.swiftmodule -module-link-name autolinking_module_inferred -I %t -swift-version 4
+// RUN: %target-swift-frontend -emit-ir %s -I %t -swift-version 4 | %FileCheck %s
+
+// Linux uses a different autolinking mechanism, based on
+// swift-autolink-extract. This file tests the Darwin mechanism.
+// UNSUPPORTED: OS=linux-gnu
+// UNSUPPORTED: OS=linux-gnueabihf
+// UNSUPPORTED: OS=freebsd
+// UNSUPPORTED: OS=linux-androideabi
+
+import autolinking_module_inferred
+
+bfunc()
+
+// CHECK: !llvm.linker.options = !{[[MODULE:![0-9]+]], [[PUBLIC:![0-9]+]], [[SWIFTONONESUPPORT:![0-9]+]], [[SWIFTCORE:![0-9]+]], [[PRIVATE:![0-9]+]], [[OTHER:![0-9]+]], [[INDIRECT:![0-9]+]], [[OTHER2:![0-9]+]], [[OBJC:![0-9]+]]}
+
+// CHECK-DAG: [[SWIFTCORE]] = !{!"-lswiftCore"}
+// CHECK-DAG: [[SWIFTONONESUPPORT]] = !{!"-lswiftSwiftOnoneSupport"}
+// CHECK-DAG: [[MODULE]] = !{!"-lautolinking_module_inferred"}
+// CHECK-DAG: [[PUBLIC]] = !{!"-lautolinking_public"}
+// CHECK-DAG: [[OTHER]] = !{!"-lautolinking_other"}
+// CHECK-DAG: [[OTHER2]] = !{!"-lautolinking_other2"}
+// CHECK-DAG: [[OBJC]] = !{!"-lobjc"}
+
+// We don't actually care about these two. As long as we autolink the libraries
+// that get used, we're okay.
+// CHECK-DAG: [[PRIVATE]] = !{!"-lautolinking_private"}
+// CHECK-DAG: [[INDIRECT]] = !{!"-lautolinking_indirect"}