Existential Specializer Pass

include/swift/AST/SILOptions.h

@@ -50,6 +50,9 @@ class SILOptions {
   /// Remove all runtime assertions during optimizations.
   bool RemoveRuntimeAsserts = false;
 
+  /// Enable existential specializer optimization.
+  bool ExistentialSpecializer = false;
+
   /// Controls whether the SIL ARC optimizations are run.
   bool EnableARCOptimizations = true;
 

include/swift/Option/FrontendOptions.td

@@ -393,6 +393,9 @@ def sil_unroll_threshold : Separate<["-"], "sil-unroll-threshold">,
   MetaVarName<"<250>">,
   HelpText<"Controls the aggressiveness of loop unrolling">;
 
+def sil_existential_specializer : Flag<["-"], "sil-existential-specializer">,
+  HelpText<"Enable SIL existential specializer optimization">;
+
 def sil_merge_partial_modules : Flag<["-"], "sil-merge-partial-modules">,
   HelpText<"Merge SIL from all partial swiftmodules into the final module">;
 

include/swift/SILOptimizer/PassManager/Passes.def

@@ -156,6 +156,8 @@ PASS(DeadStoreElimination, "dead-store-elim",
      "Dead Store Elimination")
 PASS(GenericSpecializer, "generic-specializer",
      "Generic Function Specialization on Static Types")
+PASS(ExistentialSpecializer, "existential-specializer",
+     "Existential Specializer")
 PASS(GlobalOpt, "global-opt",
      "SIL Global Optimization")
 PASS(GlobalPropertyOpt, "global-property-opt",

include/swift/SILOptimizer/Utils/Existential.h

@@ -17,9 +17,11 @@
 
 namespace swift {
 
-/// Find InitExistential from global_addr and copy_addr.
-SILValue findInitExistentialFromGlobalAddr(GlobalAddrInst *GAI,
-                                           CopyAddrInst *CAI);
+/// Find init_existential from global_addr, if any.
+SILValue findInitExistentialFromGlobalAddrAndCopyAddr(GlobalAddrInst *GAI,
+                                                  CopyAddrInst *CAI);
+SILValue findInitExistentialFromGlobalAddrAndApply(GlobalAddrInst *GAI,
+                                                  ApplySite AI, int ArgIdx);
 
 /// Returns the address of an object with which the stack location \p ASI is
 /// initialized. This is either a init_existential_addr or the destination of a

lib/Frontend/CompilerInvocation.cpp

@@ -573,6 +573,9 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
       return true;
     }
   }
+  if (Args.hasArg(OPT_sil_existential_specializer)) {
+    Opts.ExistentialSpecializer = true;
+  }
   if (const Arg *A = Args.getLastArg(OPT_num_threads)) {
     if (StringRef(A->getValue()).getAsInteger(10, Opts.NumThreads)) {
       Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,

lib/SILOptimizer/FunctionSignatureTransforms/CMakeLists.txt

@@ -3,4 +3,5 @@ set(FUNCTIONSIGNATURETRANSFORMS_SOURCES
   FunctionSignatureTransforms/DeadArgumentTransform.cpp
   FunctionSignatureTransforms/ArgumentExplosionTransform.cpp
   FunctionSignatureTransforms/OwnedToGuaranteedTransform.cpp
+  FunctionSignatureTransforms/ExistentialSpecializer.cpp
   PARENT_SCOPE)