Use correct associated context for SIL parsing

Adjust `SILModule::createEmptyModule` to accept a
FileUnit or ModuleDecl, and pass the corresponding
context for SIL generation and parsing. This
change means that SIL parsing will now correctly
use a SourceFile associated context when in
single-file mode.

Author: hamishknight

include/swift/SIL/SILModule.h

@@ -107,8 +107,6 @@ enum class SILStage {
 /// when a Swift compilation context is lowered to SIL.
 class SILModule {
   friend class SILFunctionBuilder;
-  friend class SILGenSourceFileRequest;
-  friend class SILGenWholeModuleRequest;
 
 public:
   using FunctionListType = llvm::ilist<SILFunction>;
@@ -276,8 +274,8 @@ class SILModule {
   /// invalidation message is sent.
   llvm::SetVector<DeleteNotificationHandler*> NotificationHandlers;
 
-  SILModule(ModuleDecl *M, Lowering::TypeConverter &TC,
-            const SILOptions &Options, const DeclContext *associatedDC);
+  SILModule(llvm::PointerUnion<FileUnit *, ModuleDecl *> context,
+            Lowering::TypeConverter &TC, const SILOptions &Options);
 
   SILModule(const SILModule&) = delete;
   void operator=(const SILModule&) = delete;
@@ -348,11 +346,14 @@ class SILModule {
   /// Erase a global SIL variable from the module.
   void eraseGlobalVariable(SILGlobalVariable *G);
 
-  /// Create and return an empty SIL module that we can
-  /// later parse SIL bodies directly into, without converting from an AST.
+  /// Create and return an empty SIL module suitable for generating or parsing
+  /// SIL into.
+  ///
+  /// \param context The associated decl context. This should be a FileUnit in
+  /// single-file mode, and a ModuleDecl in whole-module mode.
   static std::unique_ptr<SILModule>
-  createEmptyModule(ModuleDecl *M, Lowering::TypeConverter &TC,
-                    const SILOptions &Options);
+  createEmptyModule(llvm::PointerUnion<FileUnit *, ModuleDecl *> context,
+                    Lowering::TypeConverter &TC, const SILOptions &Options);
 
   /// Get the Swift module associated with this SIL module.
   ModuleDecl *getSwiftModule() const { return TheSwiftModule; }

lib/SIL/IR/SILModule.cpp

@@ -92,13 +92,17 @@ class SILModule::SerializationCallback final
   }
 };
 
-SILModule::SILModule(ModuleDecl *SwiftModule, TypeConverter &TC,
-                     const SILOptions &Options, const DeclContext *associatedDC)
-    : TheSwiftModule(SwiftModule),
-      AssociatedDeclContext(associatedDC),
-      Stage(SILStage::Raw), Options(Options), serialized(false),
+SILModule::SILModule(llvm::PointerUnion<FileUnit *, ModuleDecl *> context,
+                     Lowering::TypeConverter &TC, const SILOptions &Options)
+    : Stage(SILStage::Raw), Options(Options), serialized(false),
       SerializeSILAction(), Types(TC) {
-  assert(AssociatedDeclContext);
+  assert(!context.isNull());
+  if (auto *file = context.dyn_cast<FileUnit *>()) {
+    AssociatedDeclContext = file;
+  } else {
+    AssociatedDeclContext = context.get<ModuleDecl *>();
+  }
+  TheSwiftModule = AssociatedDeclContext->getParentModule();
 
   // We always add the base SILModule serialization callback.
   std::unique_ptr<DeserializationNotificationHandler> callback(
@@ -123,10 +127,10 @@ SILModule::~SILModule() {
   }
 }
 
-std::unique_ptr<SILModule>
-SILModule::createEmptyModule(ModuleDecl *M, TypeConverter &TC,
-                             const SILOptions &Options) {
-  return std::unique_ptr<SILModule>(new SILModule(M, TC, Options, M));
+std::unique_ptr<SILModule> SILModule::createEmptyModule(
+    llvm::PointerUnion<FileUnit *, ModuleDecl *> context,
+    Lowering::TypeConverter &TC, const SILOptions &Options) {
+  return std::unique_ptr<SILModule>(new SILModule(context, TC, Options));
 }
 
 ASTContext &SILModule::getASTContext() const {

lib/SIL/Parser/ParseSIL.cpp

@@ -115,8 +115,8 @@ ParseSILModuleRequest::evaluate(Evaluator &evaluator,
   auto bufferID = SF->getBufferID();
   assert(bufferID);
 
-  auto *mod = SF->getParentModule();
-  auto silMod = SILModule::createEmptyModule(mod, desc.conv, desc.opts);
+  auto silMod = SILModule::createEmptyModule(desc.context, desc.conv,
+                                             desc.opts);
   SILParserState parserState(silMod.get());
   Parser parser(*bufferID, *SF, parserState.Impl.get());
   PrettyStackTraceParser StackTrace(parser);
@@ -125,7 +125,7 @@ ParseSILModuleRequest::evaluate(Evaluator &evaluator,
   if (hadError) {
     // The rest of the SIL pipeline expects well-formed SIL, so if we encounter
     // a parsing error, just return an empty SIL module.
-    return SILModule::createEmptyModule(mod, desc.conv, desc.opts);
+    return SILModule::createEmptyModule(desc.context, desc.conv, desc.opts);
   }
   return silMod;
 }

lib/SILGen/SILGen.cpp

@@ -1867,8 +1867,7 @@ SILGenSourceFileRequest::evaluate(Evaluator &evaluator,
 
   auto *unit = desc.context.get<FileUnit *>();
   auto *mod = unit->getParentModule();
-  auto M = std::unique_ptr<SILModule>(
-      new SILModule(mod, desc.conv, desc.opts, unit));
+  auto M = SILModule::createEmptyModule(desc.context, desc.conv, desc.opts);
   SILGenModuleRAII scope(*M, mod);
 
   if (auto *file = dyn_cast<SourceFile>(unit)) {
@@ -1890,8 +1889,7 @@ SILGenWholeModuleRequest::evaluate(Evaluator &evaluator,
   }
 
   auto *mod = desc.context.get<ModuleDecl *>();
-  auto M = std::unique_ptr<SILModule>(
-      new SILModule(mod, desc.conv, desc.opts, mod));
+  auto M = SILModule::createEmptyModule(desc.context, desc.conv, desc.opts);
   SILGenModuleRAII scope(*M, mod);
 
   for (auto file : mod->getFiles()) {

test/IRGen/multi_file_resilience.swift

@@ -7,6 +7,11 @@
 
 // RUN: %target-swift-frontend -module-name main -I %t -emit-ir -primary-file %s %S/Inputs/OtherModule.swift | %FileCheck %s -DINT=i%target-ptrsize
 
+// Check that we correctly handle resilience when parsing as SIL + SIB.
+// RUN: %target-swift-frontend -emit-sib -module-name main %S/Inputs/OtherModule.swift -I %t -o %t/other.sib
+// RUN: %target-swift-frontend -emit-silgen -module-name main -primary-file %s %S/Inputs/OtherModule.swift -I %t -o %t/main.sil
+// RUN: %target-swift-frontend -emit-ir -module-name main -primary-file %t/main.sil %t/other.sib -I %t | %FileCheck %s -DINT=i%target-ptrsize
+
 // This is a single-module version of the test case in
 // multi_module_resilience.
 // rdar://39763787