SILGen: Remove selfType parameter from SILGenFunction::emitProtocolWitness()

Author: slavapestov

lib/SILGen/SILGenFunction.h

@@ -548,8 +548,7 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   ///
   /// This is used for both concrete witness thunks and default witness
   /// thunks.
-  void emitProtocolWitness(Type selfType,
-                           AbstractionPattern reqtOrigTy,
+  void emitProtocolWitness(AbstractionPattern reqtOrigTy,
                            CanAnyFunctionType reqtSubstTy,
                            SILDeclRef requirement,
                            SILDeclRef witness,

lib/SILGen/SILGenPoly.cpp

@@ -3304,8 +3304,7 @@ static CanType dropLastElement(CanType type) {
   return TupleType::get(elts, type->getASTContext())->getCanonicalType();
 }
 
-void SILGenFunction::emitProtocolWitness(Type selfType,
-                                         AbstractionPattern reqtOrigTy,
+void SILGenFunction::emitProtocolWitness(AbstractionPattern reqtOrigTy,
                                          CanAnyFunctionType reqtSubstTy,
                                          SILDeclRef requirement,
                                          SILDeclRef witness,
@@ -3325,12 +3324,6 @@ void SILGenFunction::emitProtocolWitness(Type selfType,
   SmallVector<ManagedValue, 8> origParams;
   collectThunkParams(loc, origParams);
 
-  // Handle special abstraction differences in "self".
-  // If the witness is a free function, drop it completely.
-  // WAY SPECULATIVE TODO: What if 'self' comprised multiple SIL-level params?
-  if (isFree)
-    origParams.pop_back();
-
   // Get the type of the witness.
   auto witnessInfo = getConstantInfo(witness);
   CanAnyFunctionType witnessSubstTy = witnessInfo.LoweredType;
@@ -3349,6 +3342,7 @@ void SILGenFunction::emitProtocolWitness(Type selfType,
   // For a free function witness, discard the 'self' parameter of the
   // requirement.
   if (isFree) {
+    origParams.pop_back();
     reqtOrigInputTy = reqtOrigInputTy.dropLastTupleElement();
     reqtSubstInputTy = dropLastElement(reqtSubstInputTy);
   }

lib/SILGen/SILGenType.cpp

@@ -609,24 +609,6 @@ SILGenModule::getWitnessTable(ProtocolConformance *conformance) {
   return table;
 }
 
-static bool maybeOpenCodeProtocolWitness(
-    SILGenFunction &SGF, ProtocolConformanceRef conformance, SILLinkage linkage,
-    Type selfInterfaceType, Type selfType, GenericEnvironment *genericEnv,
-    SILDeclRef requirement, SILDeclRef witness, SubstitutionList witnessSubs) {
-  if (auto witnessFn = dyn_cast<FuncDecl>(witness.getDecl())) {
-    if (witnessFn->getAccessorKind() == AccessorKind::IsMaterializeForSet) {
-      auto reqFn = cast<FuncDecl>(requirement.getDecl());
-      assert(reqFn->getAccessorKind() == AccessorKind::IsMaterializeForSet);
-      return SGF.maybeEmitMaterializeForSetThunk(conformance, linkage,
-                                                 selfInterfaceType, selfType,
-                                                 genericEnv, reqFn, witnessFn,
-                                                 witnessSubs);
-    }
-  }
-
-  return false;
-}
-
 SILFunction *SILGenModule::emitProtocolWitness(
     ProtocolConformanceRef conformance, SILLinkage linkage,
     IsSerialized_t isSerialized, SILDeclRef requirement, SILDeclRef witnessRef,
@@ -695,34 +677,36 @@ SILFunction *SILGenModule::emitProtocolWitness(
   PrettyStackTraceSILFunction trace("generating protocol witness thunk", f);
 
   // Create the witness.
-  Type selfInterfaceType;
-  Type selfType;
-
-  // If the witness is a free function, there is no Self type.
-  if (!isFree) {
-    auto *proto = cast<ProtocolDecl>(requirement.getDecl()->getDeclContext());
-    selfInterfaceType = proto->getSelfInterfaceType().subst(reqtSubMap);
-    selfType = GenericEnvironment::mapTypeIntoContext(
-        genericEnv, selfInterfaceType);
-  }
-
   SILGenFunction SGF(*this, *f);
 
   // Substitutions mapping the generic parameters of the witness to
   // archetypes of the witness thunk generic environment.
   auto witnessSubs = witness.getSubstitutions();
 
-  // Open-code certain protocol witness "thunks".
-  if (maybeOpenCodeProtocolWitness(SGF, conformance, linkage,
-                                   selfInterfaceType, selfType, genericEnv,
-                                   requirement, witnessRef, witnessSubs)) {
-    assert(!isFree);
-    return f;
+  // Open-code protocol witness thunks for materializeForSet.
+  if (auto witnessFn = dyn_cast<FuncDecl>(witnessRef.getDecl())) {
+    if (witnessFn->getAccessorKind() == AccessorKind::IsMaterializeForSet) {
+      assert(!isFree);
+
+      auto *proto = cast<ProtocolDecl>(requirement.getDecl()->getDeclContext());
+      auto selfInterfaceType = proto->getSelfInterfaceType().subst(reqtSubMap);
+      auto selfType = GenericEnvironment::mapTypeIntoContext(
+          genericEnv, selfInterfaceType);
+
+      auto reqFn = cast<FuncDecl>(requirement.getDecl());
+      assert(reqFn->getAccessorKind() == AccessorKind::IsMaterializeForSet);
+
+      if (SGF.maybeEmitMaterializeForSetThunk(conformance, linkage,
+                                              selfInterfaceType, selfType,
+                                              genericEnv, reqFn, witnessFn,
+                                              witnessSubs))
+        return f;
+
+      // Proceed down the normal path.
+    }
   }
 
-  SGF.emitProtocolWitness(selfType,
-                          AbstractionPattern(reqtOrigTy),
-                          reqtSubstTy,
+  SGF.emitProtocolWitness(AbstractionPattern(reqtOrigTy), reqtSubstTy,
                           requirement, witnessRef,
                           witnessSubs, isFree);