Allow us to find stdlib types in the current file when there's no Swift library

Some type checker invariants require that certain types like Error or
Never exist in the standard library. When the standard library isn't
loaded, we can get crashes. This only happens under `-parse-stdlib`,
which is used in some test cases. Allow lookup for standard library
types to look into the main module in such cases, and add the
appropriate declarations to these tests.

Author: DougGregor

lib/AST/ASTContext.cpp

@@ -940,7 +940,10 @@ DECL_CLASS *ASTContext::get##NAME##Decl() const { \
   if (getImpl().NAME##Decl) \
     return getImpl().NAME##Decl; \
   SmallVector<ValueDecl *, 1> results; \
-  lookupInSwiftModule(#NAME, results); \
+  if (auto stdlibModule = getStdlibModule()) \
+    lookupInModule(stdlibModule, #NAME, results); \
+  else \
+    lookupInModule(MainModule, #NAME, results); \
   for (auto result : results) { \
     if (auto type = dyn_cast<DECL_CLASS>(result)) { \
       auto params = type->getGenericParams(); \
@@ -1169,6 +1172,12 @@ ProtocolDecl *ASTContext::getProtocol(KnownProtocolKind kind) const {
     break;
   default:
     M = getStdlibModule();
+
+    // Fall back to looking into the current module for these types.
+    // This only happens with -parse-stdlib when the Swift module isn't
+    // imported, e.g., in test cases.
+    if (!M)
+      M = MainModule;
     break;
   }
 

test/IRGen/dllimport.swift

@@ -3,6 +3,9 @@
 
 // REQUIRES: CODEGENERATOR=ARM
 
+protocol Error { }
+enum Never { }
+
 import dllexport
 
 public func get_ci() -> dllexport.c {

test/IRGen/ivar_destroyer.sil

@@ -2,6 +2,9 @@
 
 // REQUIRES: CPU=x86_64
 
+protocol Error { }
+enum Never { }
+
 // CHECK: [[OBJCCLASS:%objc_class]] = type
 // CHECK: [[OPAQUE:%swift.opaque]] = type opaque
 // CHECK: [[TYPE:%swift.type]] = type

test/IRGen/protocol_synthesized.swift

@@ -302,3 +302,6 @@ public protocol ExpressibleByArrayLiteral {
 
 public protocol Equatable {
 }
+
+protocol Error { }
+enum Never { }

test/IRGen/vtable_non_overridden.sil

@@ -10,6 +10,9 @@ class InternalA {
   func bas()
 }
 
+protocol Error { }
+enum Never { }
+
 sil @InternalA_foo : $@convention(method) (@guaranteed InternalA) -> ()
 sil @InternalA_bar : $@convention(method) (@guaranteed InternalA) -> ()
 sil @InternalA_bas : $@convention(method) (@guaranteed InternalA) -> ()

test/SIL/OwnershipVerifier/definite_init.sil

@@ -14,6 +14,9 @@ struct Bool {
   var value: Builtin.Int1
 }
 
+protocol Error { }
+enum Never { }
+
 // This file is meant to contain tests that previously the verifier treated
 // incorrectly. This is important to ensure that the verifier does not
 // regress. It should only deal with use matching in a DI context.

test/SIL/OwnershipVerifier/objc_use_verifier.sil

@@ -6,6 +6,9 @@
 
 class Protocol : NSBurrito {}
 
+protocol Error { }
+enum Never { }
+
 sil [ossa] @test_objc_protocol : $@convention(thin) () -> @owned Protocol {
 bb0:
   %0 = objc_protocol #NSBurrito : $Protocol

test/SIL/Serialization/vtable.sil

@@ -6,6 +6,9 @@ sil_stage canonical
 
 import Builtin
 
+protocol Error { }
+enum Never { }
+
 public class Base {
   func m1()
   func m2()

test/SILGen/auto_closures.swift

@@ -1,6 +1,9 @@
 
 // RUN: %target-swift-emit-silgen -module-name auto_closures -parse-stdlib -swift-version 5 %s | %FileCheck %s
 
+protocol Error { }
+enum Never { }
+
 struct Bool {}
 var false_ = Bool()
 

test/SILOptimizer/basic-callee-printer.sil

@@ -3,6 +3,9 @@
 
 sil_stage canonical
 
+protocol Error { }
+enum Never { }
+
 sil private @private_bottom : $@convention(thin) () -> () {
 bb0:
   %0 = tuple ()

test/SILOptimizer/function_order.sil

@@ -4,6 +4,9 @@ sil_stage canonical
 
 import Builtin
 
+protocol Error { }
+enum Never { }
+
 // CHECK: Bottom up function order:
 // CHECK-NEXT: private_bottom
 // CHECK-NEXT: private_middle

test/SILOptimizer/prune-vtables.sil

@@ -3,6 +3,9 @@
 
 sil_stage canonical
 
+protocol Error { }
+enum Never { }
+
 private class PrivateA {
   func noOverrides() {}
   func yesOverrides() {}

test/SILOptimizer/rcidentity.sil

@@ -2,6 +2,9 @@
 
 import Builtin
 
+protocol Error { }
+enum Never { }
+
 ///////////////////////
 // NonTest Utilities //
 ///////////////////////

test/SILOptimizer/typed-access-tb-aa.sil

@@ -4,6 +4,9 @@
 
 import Builtin
 
+protocol Error { }
+enum Never { }
+
 ///////////////////////
 // Type Declarations //
 ///////////////////////

test/embedded/classes-methods-no-stdlib.swift

@@ -11,6 +11,9 @@ public class MySubClass: MyClass {
   override func foo() { }
 }
 
+protocol Error { }
+enum Never { }
+
 // CHECK: @"$s4main7MyClassCN" = {{.*}}<{ ptr, ptr, ptr, ptr, ptr }> <{ ptr null, ptr @"$s4main7MyClassCfD", ptr @"$s4main7MyClassC3fooyyF", ptr @"$s4main7MyClassC3baryyF", ptr @swift_deletedMethodError }>
 // CHECK: @"$s4main10MySubClassCN" = {{.*}}<{ ptr, ptr, ptr, ptr, ptr }> <{ ptr @"$s4main7MyClassCN", ptr @"$s4main10MySubClassCfD", ptr @"$s4main10MySubClassC3fooyyF", ptr @"$s4main7MyClassC3baryyF", ptr @"$s4main10MySubClassCACycfC" }>