[SILGen] InitAccessors: Generalize AccessorComponent::emitValue

Instead of taking a setter type, let's switch over to a more general
`AccessorKind` which allows us to cover init accessors and simplify
`emitApplySetterToBase`.

Author: xedin

lib/SILGen/SILGenFunction.cpp

@@ -1747,7 +1747,7 @@ ParamDecl *SILGenFunction::isMappedToInitAccessorArgument(VarDecl *property) {
   return arg->second;
 }
 
-std::pair<SILValue, CanSILFunctionType>
+SILValue
 SILGenFunction::emitApplyOfSetterToBase(SILLocation loc, SILDeclRef setter,
                                         ManagedValue base,
                                         SubstitutionMap substitutions) {
@@ -1775,8 +1775,7 @@ SILGenFunction::emitApplyOfSetterToBase(SILLocation loc, SILDeclRef setter,
                                       getTypeExpansionContext());
   };
 
-  auto setterTy = getSetterType(setterFRef);
-  SILFunctionConventions setterConv(setterTy, SGM.M);
+  SILFunctionConventions setterConv(getSetterType(setterFRef), SGM.M);
 
   // Emit captures for the setter
   SmallVector<SILValue, 4> capturedArgs;
@@ -1814,5 +1813,5 @@ SILGenFunction::emitApplyOfSetterToBase(SILLocation loc, SILDeclRef setter,
   PartialApplyInst *setterPAI =
       B.createPartialApply(loc, setterFRef, substitutions, capturedArgs,
                            ParameterConvention::Direct_Guaranteed);
-  return {emitManagedRValueWithCleanup(setterPAI).getValue(), setterTy};
+  return emitManagedRValueWithCleanup(setterPAI).getValue();
 }

lib/SILGen/SILGenFunction.h

@@ -814,9 +814,9 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   void emitInitAccessor(AccessorDecl *accessor);
 
   /// Generates code to emit the given setter reference to the given base value.
-  std::pair<SILValue, CanSILFunctionType>
-  emitApplyOfSetterToBase(SILLocation loc, SILDeclRef setter, ManagedValue base,
-                          SubstitutionMap substitutions);
+  SILValue emitApplyOfSetterToBase(SILLocation loc, SILDeclRef setter,
+                                   ManagedValue base,
+                                   SubstitutionMap substitutions);
 
   /// Generates code to destroy the instance variables of a class.
   ///

lib/SILGen/SILGenLValue.cpp

@@ -1439,8 +1439,23 @@ namespace {
     }
 
     ManagedValue emitValue(SILGenFunction &SGF, SILLocation loc, VarDecl *field,
-                           Type fieldType, ArgumentSource &&value,
-                           CanSILFunctionType accessorTy) {
+                           ArgumentSource &&value, AccessorKind accessorKind) {
+      auto accessorInfo = SGF.getConstantInfo(
+          SGF.getTypeExpansionContext(),
+          SILDeclRef(field->getOpaqueAccessor(accessorKind)));
+
+      auto fieldTy = field->getValueInterfaceType();
+      auto accessorTy = SGF.SGM.Types
+                            .getLoweredType(accessorInfo.SILFnType,
+                                            SGF.getTypeExpansionContext())
+                            .castTo<SILFunctionType>();
+
+      if (!Substitutions.empty()) {
+        fieldTy = fieldTy.subst(Substitutions);
+        accessorTy = accessorTy->substGenericArgs(
+            SGF.SGM.M, Substitutions, SGF.getTypeExpansionContext());
+      }
+
       SILFunctionConventions accessorConv(accessorTy, SGF.SGM.M);
 
       // FIXME: This should use CallEmission instead of doing everything
@@ -1454,19 +1469,23 @@ namespace {
         loweredSubstArgType =
             SILType::getPrimitiveAddressType(loweredSubstArgType.getASTType());
       }
+
       auto loweredSubstParamTy = SILType::getPrimitiveType(
           param.getArgumentType(SGF.SGM.M, accessorTy,
                                 SGF.getTypeExpansionContext()),
           loweredSubstArgType.getCategory());
+
       // Handle reabstraction differences.
       if (Mval.getType() != loweredSubstParamTy) {
         Mval = SGF.emitSubstToOrigValue(
             loc, Mval, SGF.SGM.Types.getAbstractionPattern(field),
-            fieldType->getCanonicalType());
+            fieldTy->getCanonicalType());
       }
 
+      auto newValueArgIdx = accessorConv.getNumIndirectSILResults();
       // If we need the argument in memory, materialize an address.
-      if (accessorConv.getSILArgumentConvention(0).isIndirectConvention() &&
+      if (accessorConv.getSILArgumentConvention(newValueArgIdx)
+              .isIndirectConvention() &&
           !Mval.getType().isAddress()) {
         Mval = Mval.materialize(SGF, loc);
       }
@@ -1503,29 +1522,21 @@ namespace {
     void set(SILGenFunction &SGF, SILLocation loc, ArgumentSource &&value,
              ManagedValue base) &&
         override {
-      VarDecl *field = cast<VarDecl>(Storage);
-      auto fieldType = field->getValueInterfaceType();
-      if (!Substitutions.empty()) {
-        fieldType = fieldType.subst(Substitutions);
-      }
-
+      auto *field = cast<VarDecl>(Storage);
       // Emit the init accessor function partially applied to the base.
       SILValue initFRef =
           emitPartialInitAccessorReference(SGF, loc, getAccessorDecl());
 
       SILValue setterFRef;
-      CanSILFunctionType setterTy;
-
       if (auto *setter = field->getOpaqueAccessor(AccessorKind::Set)) {
-        std::tie(setterFRef, setterTy) = SGF.emitApplyOfSetterToBase(
-            loc, SILDeclRef(setter), base, Substitutions);
+        setterFRef = SGF.emitApplyOfSetterToBase(loc, SILDeclRef(setter), base,
+                                                 Substitutions);
       } else {
         setterFRef = SILUndef::get(initFRef->getType(), SGF.F);
-        setterTy = initFRef->getType().castTo<SILFunctionType>();
       }
 
       auto Mval =
-          emitValue(SGF, loc, field, fieldType, std::move(value), setterTy);
+          emitValue(SGF, loc, field, std::move(value), AccessorKind::Init);
 
       SGF.B.createAssignOrInit(loc, base.getValue(), Mval.forward(SGF),
                                initFRef, setterFRef, AssignOrInitInst::Unknown);
@@ -1818,15 +1829,13 @@ namespace {
         ManagedValue initFn = SGF.emitManagedRValueWithCleanup(initPAI);
 
         // Create the allocating setter function. It captures the base address.
-        SILValue setterFn;
-        CanSILFunctionType setterTy;
-        std::tie(setterFn, setterTy) =
+        SILValue setterFn =
             SGF.emitApplyOfSetterToBase(loc, Accessor, base, Substitutions);
 
         // Create the assign_by_wrapper with the initializer and setter.
 
         auto Mval =
-            emitValue(SGF, loc, field, FieldType, std::move(value), setterTy);
+            emitValue(SGF, loc, field, std::move(value), AccessorKind::Set);
 
         SGF.B.createAssignByWrapper(loc, Mval.forward(SGF), proj.forward(SGF),
                                     initFn.getValue(), setterFn,