libswift: implement isFieldOnlyNonTrivialField

Author: MaxDesiatov

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ReleaseDevirtualizer.swift

@@ -59,7 +59,7 @@ let releaseDevirtualizerPass = FunctionPass(
   }
 )
 
-/// Tries to de-virtualize the final release of a stack promoted object.
+/// Tries to de-virtualize the final release of a stack-promoted object.
 private func tryDevirtualizeReleaseOfObject(
   _ context: PassContext,
   _ release: RefCountingInst,
@@ -157,12 +157,12 @@ private extension Instruction {
     let function = self.function
 
     // For each operand...
-    for op in operands.enumerated() {
+    for op in operands {
       // If the operand is not trivial...
-      if !op.type.isTrivial(in: function) {
+      if !op.value.type.isTrivial(in: function) {
         // And we have not found a `candidateElt` yet, set index to `op` and continue.
         if candidateElt == nil {
-          candidateElt = op
+          candidateElt = op.value
           continue
         }
 
@@ -186,7 +186,7 @@ private extension TupleExtractInst {
 
     // Ok, we know that the elt we are extracting is non-trivial. Make sure that
     // we have no other non-trivial elts.
-    let opTy = operand[0].type
+    let opType = operand.type
     let fieldNo = self.fieldIndex
 
     // For each element index of the tuple...
@@ -212,3 +212,25 @@ private extension TupleExtractInst {
     return true
   }
 }
+
+private extension StructExtractInst {
+  var isFieldOnlyNonTrivialField: Bool {
+    let function = self.function
+
+    if type.isTrivial(in: function) {
+      return false
+    }
+
+    let structType = operand.type
+
+    for (i, fieldType) in structType.getStructFields(in: function).enumerated() {
+      if i == fieldIndex || fieldType.isTrivial(in: function) {
+        continue
+      }
+
+      return false
+    }
+
+    return true
+  }
+}

SwiftCompilerSources/Sources/SIL/Instruction.swift

@@ -388,9 +388,6 @@ public final class StructInst: SingleValueInstruction {
 
 public final class StructExtractInst: SingleValueInstruction, UnaryInstruction {
   public var fieldIndex: Int { StructExtractInst_fieldIndex(bridged) }
-  public var isFieldOnlyNonTrivialField: Bool {
-    StructExtractInst_isFieldOnlyNonTrivialField(bridged)
-  }
 }
 
 public

SwiftCompilerSources/Sources/SIL/Type.swift

@@ -13,7 +13,7 @@
 import SILBridging
 
 public struct Type : CustomStringConvertible, CustomReflectable {
-  var bridged: BridgedType
+  public let bridged: BridgedType
 
   public var isAddress: Bool { SILType_isAddress(bridged) != 0 }
   public var isObject: Bool { !isAddress }
@@ -37,17 +37,23 @@ public struct Type : CustomStringConvertible, CustomReflectable {
     return idx >= 0 ? idx : nil
   }
 
-  public func getFieldTypeOfNominal(fieldIndex: Int, in function: Function) -> Type {
-    SILType_getTypeOfField(bridged, fieldIndex, function.bridged).type
+  public func getStructFields(in function: Function) -> StructElementArray {
+    StructElementArray(type: self, function: function)
   }
 
   public var description: String { SILType_debugDescription(bridged).takeString() }
 
   public var customMirror: Mirror { Mirror(self, children: []) }
 }
 
+extension Type: Equatable {
+  public static func ==(lhs: Type, rhs: Type) -> Bool { 
+    lhs.bridged.typePtr == rhs.bridged.typePtr
+  }
+}
+
 public struct TupleElementArray : RandomAccessCollection, FormattedLikeArray {
-  fileprivate let type: Type
+  public let type: Type
 
   public var startIndex: Int { return 0 }
   public var endIndex: Int { SILType_getNumTupleElements(type.bridged) }
@@ -60,3 +66,15 @@ public struct TupleElementArray : RandomAccessCollection, FormattedLikeArray {
 extension BridgedType {
   var type: Type { Type(bridged: self) }
 }
+
+public struct StructElementArray : RandomAccessCollection, FormattedLikeArray {
+  public let type: Type
+  let function: Function
+
+  public var startIndex: Int { return 0 }
+  public var endIndex: Int { SILType_getNumStructFields(type.bridged) }
+
+  public subscript(_ index: Int) -> Type {
+    SILType_getStructFieldType(type.bridged, index, function.bridged).type
+  }
+}

include/swift/SIL/SILBridging.h

@@ -214,11 +214,12 @@ SwiftInt SILType_isTuple(BridgedType type);
 SwiftInt SILType_isEnum(BridgedType type);
 SwiftInt SILType_getFieldIdxOfNominalType(BridgedType type,
                                           BridgedStringRef fieldName);
-BridgedType SILType_getTypeOfField(BridgedType type, SwiftInt fieldIndex,
-                                   BridgedFunction inFunction);
 SwiftInt SILType_getNumTupleElements(BridgedType type);
 BridgedType SILType_getTupleElementType(BridgedType type, SwiftInt elementIdx);
 BridgedSubstitutionMap SILType_getContextSubstitutionMap(BridgedType);
+SwiftInt SILType_getNumStructFields(BridgedType type);
+BridgedType SILType_getStructFieldType(BridgedType type, SwiftInt index,
+                                       BridgedFunction function);
 
 BridgedBasicBlock SILArgument_getParent(BridgedArgument argument);
 
@@ -246,7 +247,6 @@ BridgedFunction FunctionRefInst_getReferencedFunction(BridgedInstruction fri);
 SwiftInt TupleExtractInst_fieldIndex(BridgedInstruction tei);
 SwiftInt TupleElementAddrInst_fieldIndex(BridgedInstruction teai);
 SwiftInt StructExtractInst_fieldIndex(BridgedInstruction sei);
-bool StructExtractInst_isFieldOnlyNonTrivialField(BridgedInstruction sei);
 OptionalBridgedValue StructInst_getUniqueNonTrivialFieldValue(BridgedInstruction si);
 SwiftInt StructElementAddrInst_fieldIndex(BridgedInstruction seai);
 SwiftInt EnumInst_caseIndex(BridgedInstruction ei);

lib/SIL/Utils/SILBridging.cpp

@@ -380,12 +380,6 @@ SwiftInt SILType_isEnum(BridgedType type) {
   return castToSILType(type).getEnumOrBoundGenericEnum() ? 1 : 0;
 }
 
-SwiftInt SILType_isNonTrivialOrContainsRawPointer(BridgedType type,
-                                                  BridgedFunction function) {
-  SILFunction *f = castToFunction(function);
-  return castToSILType(type).isNonTrivialOrContainsRawPointer(*f);
-}
-
 SwiftInt SILType_getFieldIdxOfNominalType(BridgedType type,
                                           BridgedStringRef fieldName) {
   SILType ty = castToSILType(type);
@@ -414,20 +408,6 @@ SwiftInt SILType_getFieldIdxOfNominalType(BridgedType type,
   return -1;
 }
 
-BridgedType SILType_getTypeOfField(BridgedType type, SwiftInt fieldIndex,
-                                   BridgedFunction inFunction) {
-  SILType ty = castToSILType(type);
-  auto *nominal = ty.getNominalOrBoundGenericNominal();
-  assert(nominal);
-
-  VarDecl *field = getIndexedField(nominal, (unsigned)fieldIndex);
-  assert(field);
-
-  SILFunction *f = castToFunction(inFunction);
-  SILType fieldTy = ty.getFieldType(field, f->getModule(),f->getTypeExpansionContext());
-  return {fieldTy.getOpaqueValue()};
-}
-
 SwiftInt SILType_getNumTupleElements(BridgedType type) {
   TupleType *tupleTy = castToSILType(type).castTo<TupleType>();
   return tupleTy->getNumElements();
@@ -439,6 +419,25 @@ BridgedType SILType_getTupleElementType(BridgedType type, SwiftInt elementIdx) {
   return {elmtTy.getOpaqueValue()};
 }
 
+SwiftInt SILType_getNumStructFields(BridgedType type) {
+  StructType *ty = castToSILType(type).castTo<StructType>();
+  return ty->getDecl()->getStoredProperties().size();
+}
+
+BridgedType SILType_getStructFieldType(BridgedType type, SwiftInt index,
+                                       BridgedFunction function) {
+  SILType silType = castToSILType(type);
+  SILFunction *silFunction = castToFunction(function);
+
+  StructType *ty = silType.castTo<StructType>();
+  VarDecl *property = ty->getDecl()->getStoredProperties()[index];
+
+  SILType propertyType = silType.getFieldType(
+      property, silFunction->getModule(), TypeExpansionContext(*silFunction));
+
+  return {propertyType.getOpaqueValue()};
+}
+
 //===----------------------------------------------------------------------===//
 //                            SILGlobalVariable
 //===----------------------------------------------------------------------===//
@@ -553,10 +552,6 @@ SwiftInt StructExtractInst_fieldIndex(BridgedInstruction sei) {
   return castToInst<StructExtractInst>(sei)->getFieldIndex();
 }
 
-bool StructExtractInst_isFieldOnlyNonTrivialField(BridgedInstruction sei) {
-  return castToInst<StructExtractInst>(sei)->isFieldOnlyNonTrivialField();
-}
-
 OptionalBridgedValue StructInst_getUniqueNonTrivialFieldValue(BridgedInstruction si) {
   return {castToInst<StructInst>(si)->getUniqueNonTrivialFieldValue()};
 }