ExistentialSpecializer Pass (without SILCombine/ConcreteType Propagation)

Author: Raj Barik

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

@@ -424,6 +424,9 @@ 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

@@ -160,6 +160,8 @@ 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",

lib/Frontend/CompilerInvocation.cpp

@@ -608,6 +608,9 @@ 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 +3,6 @@ silopt_register_sources(
   DeadArgumentTransform.cpp
   ArgumentExplosionTransform.cpp
   OwnedToGuaranteedTransform.cpp
+  ExistentialSpecializer.cpp
+  ExistentialTransform.cpp
 )