[embedded] Only run the late DeadFunctionElimination if embedded mode is on

Author: kubamracek

include/swift/AST/SILOptions.h

@@ -276,6 +276,9 @@ class SILOptions {
   /// is a single SILModule in a single thread.
   bool checkSILModuleLeaks = false;
 
+  /// Are we building in embedded Swift mode?
+  bool EmbeddedSwift = false;
+
   /// The name of the file to which the backend should save optimization
   /// records.
   std::string OptRecordFile;

lib/Frontend/CompilerInvocation.cpp

@@ -3118,6 +3118,7 @@ bool CompilerInvocation::parseArgs(
     IRGenOpts.InternalizeAtLink = true;
     IRGenOpts.DisableLegacyTypeInfo = true;
     SILOpts.CMOMode = CrossModuleOptimizationMode::Everything;
+    SILOpts.EmbeddedSwift = true;
   }
 
   return false;

lib/SILOptimizer/PassManager/PassPipeline.cpp

@@ -891,8 +891,12 @@ SILPassPipelinePlan::getIRGenPreparePassPipeline(const SILOptions &Options) {
   // boundaries as required by the ABI.
   P.addLoadableByAddress();
 
-  // For embedded Swift: Remove all unspecialized functions.
-  P.addLateDeadFunctionAndGlobalElimination();
+  if (Options.EmbeddedSwift) {
+    // For embedded Swift: Remove all unspecialized functions. This is important
+    // to avoid having debuginfo references to these functions that we don't
+    // want to emit in IRGen.
+    P.addLateDeadFunctionAndGlobalElimination();
+  }
 
   if (Options.EnablePackMetadataStackPromotion) {
     // Insert marker instructions indicating where on-stack pack metadata