IRGen: destructiveProjectEnumData() value witness doesn't need a return value

slavapestov · slavapestov · commit 9ee10e7d3913 · 2015-11-30T13:32:55.000-08:00
The rest of the runtime assumes the payload starts at the beginning
of the enum, so simplify some code by removing the return value here.
diff --git a/include/swift/Runtime/Metadata.h b/include/swift/Runtime/Metadata.h
@@ -542,8 +542,9 @@ typedef unsigned getEnumTag(const OpaqueValue *src,
 /// bits, leaving behind a value of the inhabited case payload type.
 /// If the case is indirect, the payload can then be projected from the box
 /// with swift_projectBox().
-typedef OpaqueValue *destructiveProjectEnumData(OpaqueValue *src,
-                                                const Metadata *self);
+typedef void destructiveProjectEnumData(OpaqueValue *src,
+                                        const Metadata *self);
+
 
 } // end namespace value_witness_types
 
@@ -1066,8 +1067,8 @@ struct Metadata {
   unsigned vw_getEnumTag(const OpaqueValue *value) const {
     return getValueWitnesses()->_asEVWT()->getEnumTag(value, this);
   }
-  OpaqueValue *vw_destructiveProjectEnumData(OpaqueValue *value) const {
-    return getValueWitnesses()->_asEVWT()->destructiveProjectEnumData(value, this);
+  void vw_destructiveProjectEnumData(OpaqueValue *value) const {
+    getValueWitnesses()->_asEVWT()->destructiveProjectEnumData(value, this);
   }
   
   /// Get the nominal type descriptor if this metadata describes a nominal type,
diff --git a/lib/IRGen/GenOpaque.cpp b/lib/IRGen/GenOpaque.cpp
@@ -171,14 +171,15 @@ static llvm::Type *createWitnessType(IRGenModule &IGM, ValueWitness index) {
       ->getPointerTo();
   }
 
-  /// U *(*destructiveProjectEnumData)(T *obj, M *self);
+  /// void (*destructiveProjectEnumData)(T *obj, M *self);
   case ValueWitness::DestructiveProjectEnumData: {
+    llvm::Type *voidTy = IGM.VoidTy;
     llvm::Type *ptrTy = IGM.OpaquePtrTy;
     llvm::Type *metaTy = IGM.TypeMetadataPtrTy;
 
     llvm::Type *args[] = {ptrTy, metaTy};
 
-    return llvm::FunctionType::get(ptrTy, args, /*isVarArg*/ false)
+    return llvm::FunctionType::get(voidTy, args, /*isVarArg*/ false)
       ->getPointerTo();
   }
 
diff --git a/lib/IRGen/GenProto.cpp b/lib/IRGen/GenProto.cpp
@@ -1135,7 +1135,7 @@ static void buildValueWitnessFunction(IRGenModule &IGM,
           Address(value, type.getBestKnownAlignment()));
     }
 
-    IGF.Builder.CreateRet(value);
+    IGF.Builder.CreateRetVoid();
     return;
   }
 
diff --git a/lib/IRGen/ValueWitness.h b/lib/IRGen/ValueWitness.h
@@ -286,9 +286,9 @@ enum class ValueWitness : unsigned {
   /// Given a valid object of this enum type, extracts the tag value indicating
   /// which case of the enum is inhabited.
   GetEnumTag = First_EnumValueWitness,
-  ///   U *(*destructiveProjectEnumData)(T *obj, unsigned tag, M *self);
+  ///   void (*destructiveProjectEnumData)(T *obj, M *self);
   /// Given a valid object of this enum type, destructively extracts the
-  /// associated payload and returns a pointer to that payload.
+  /// associated payload.
   DestructiveProjectEnumData,
   Last_EnumValueWitness = DestructiveProjectEnumData,
 
diff --git a/stdlib/public/runtime/Reflection.mm b/stdlib/public/runtime/Reflection.mm
@@ -544,7 +544,8 @@ StringMirrorTuple swift_EnumMirror_subscript(intptr_t i,
 
   owner = pair.first;
   type->vw_initializeWithTake(pair.second, const_cast<OpaqueValue *>(value));
-  value = type->vw_destructiveProjectEnumData(pair.second);
+  type->vw_destructiveProjectEnumData(pair.second);
+  value = pair.second;
 
   // If the payload is indirect, we need to jump through the box to get it.
   if (indirect) {
diff --git a/test/IRGen/enum_value_semantics.sil b/test/IRGen/enum_value_semantics.sil
@@ -32,7 +32,7 @@ import Builtin
 // CHECK:   i8* null,
 // CHECK:   i8* null,
 // CHECK:   i8* bitcast (i32 (%swift.opaque*, %swift.type*)* @_TwugO20enum_value_semantics20SinglePayloadTrivial to i8*),
-// CHECK:   i8* bitcast (%swift.opaque* (%swift.opaque*, %swift.type*)* @_TwupO20enum_value_semantics20SinglePayloadTrivial to i8*)
+// CHECK:   i8* bitcast (void (%swift.opaque*, %swift.type*)* @_TwupO20enum_value_semantics20SinglePayloadTrivial to i8*)
 // CHECK: ]
 
 // CHECK: @_TMfO20enum_value_semantics20SinglePayloadTrivial = internal constant { {{.*}}* } {
@@ -68,7 +68,7 @@ import Builtin
 // CHECK:   i8* bitcast (void (%swift.opaque*, i32, %swift.type*)* @_TwxsO20enum_value_semantics23SinglePayloadNontrivial to i8*)
 // CHECK:   i8* bitcast (i32 (%swift.opaque*, %swift.type*)* @_TwxgO20enum_value_semantics23SinglePayloadNontrivial to i8*)
 // CHECK:   i8* bitcast (i32 (%swift.opaque*, %swift.type*)* @_TwugO20enum_value_semantics23SinglePayloadNontrivial to i8*),
-// CHECK:   i8* bitcast (%swift.opaque* (%swift.opaque*, %swift.type*)* @_TwupO20enum_value_semantics23SinglePayloadNontrivial to i8*)
+// CHECK:   i8* bitcast (void (%swift.opaque*, %swift.type*)* @_TwupO20enum_value_semantics23SinglePayloadNontrivial to i8*)
 // CHECK: ]
 
 // CHECK: @_TMfO20enum_value_semantics23SinglePayloadNontrivial = internal constant { {{.*}}* } {

Original file line number	Diff line number	Diff line change
`@@ -171,14 +171,15 @@ static llvm::Type *createWitnessType(IRGenModule &IGM, ValueWitness index) {`
`171`	`171`	`->getPointerTo();`
`172`	`172`	`}`
`173`	`173`
`174`		`- /// U (destructiveProjectEnumData)(T obj, M self);`
	`174`	`+ /// void (destructiveProjectEnumData)(T obj, M *self);`
`175`	`175`	`case ValueWitness::DestructiveProjectEnumData: {`
	`176`	`+ llvm::Type *voidTy = IGM.VoidTy;`
`176`	`177`	`llvm::Type *ptrTy = IGM.OpaquePtrTy;`
`177`	`178`	`llvm::Type *metaTy = IGM.TypeMetadataPtrTy;`
`178`	`179`
`179`	`180`	`llvm::Type *args[] = {ptrTy, metaTy};`
`180`	`181`
`181`		`- return llvm::FunctionType::get(ptrTy, args, /isVarArg/ false)`
	`182`	`+ return llvm::FunctionType::get(voidTy, args, /isVarArg/ false)`
`182`	`183`	`->getPointerTo();`
`183`	`184`	`}`
`184`	`185`
Original file line number	Diff line number	Diff line change
`@@ -1135,7 +1135,7 @@ static void buildValueWitnessFunction(IRGenModule &IGM,`
`1135`	`1135`	`Address(value, type.getBestKnownAlignment()));`
`1136`	`1136`	`}`
`1137`	`1137`
`1138`		`- IGF.Builder.CreateRet(value);`
	`1138`	`+ IGF.Builder.CreateRetVoid();`
`1139`	`1139`	`return;`
`1140`	`1140`	`}`
`1141`	`1141`