SIL: make isLexical a protocol requirement of Value

This avoids the need for checking if a value is a `move_value`, `begin_borrow` or function argument to get the is-lexical information.

Author: eeckstein

SwiftCompilerSources/Sources/SIL/Argument.swift

@@ -32,6 +32,8 @@ public class Argument : Value, Hashable {
 
   public var isReborrow: Bool { bridged.isReborrow() }
 
+  public var isLexical: Bool { false }
+
   public var varDecl: VarDecl? { bridged.getVarDecl().getAs(VarDecl.self) }
 
   public var sourceLoc: SourceLoc? { varDecl?.nameLoc }
@@ -50,6 +52,10 @@ final public class FunctionArgument : Argument {
     parentFunction.argumentConventions[index]
   }
 
+  public override var isLexical: Bool {
+    bridged.FunctionArgument_isLexical()
+  }
+
   public var isSelf: Bool {
     parentFunction.argumentConventions.selfIndex == index
   }

SwiftCompilerSources/Sources/SIL/Instruction.swift

@@ -198,6 +198,8 @@ public class SingleValueInstruction : Instruction, Value {
   public static func ==(lhs: SingleValueInstruction, rhs: SingleValueInstruction) -> Bool {
     lhs === rhs
   }
+
+  public var isLexical: Bool { false }
 }
 
 public final class MultipleValueInstructionResult : Value, Hashable {
@@ -209,6 +211,8 @@ public final class MultipleValueInstructionResult : Value, Hashable {
 
   public var parentBlock: BasicBlock { parentInstruction.parentBlock }
 
+  public var isLexical: Bool { false }
+
   public var index: Int { bridged.getIndex() }
 
   var bridged: BridgedMultiValueResult {
@@ -1028,7 +1032,7 @@ final public class UncheckedOwnershipConversionInst : SingleValueInstruction {}
 final public class MoveValueInst : SingleValueInstruction, UnaryInstruction {
   public var fromValue: Value { operand.value }
 
-  public var isLexical: Bool { bridged.MoveValue_isLexical() }
+  public override var isLexical: Bool { bridged.MoveValue_isLexical() }
   public var hasPointerEscape: Bool { bridged.MoveValue_hasPointerEscape() }
   public var isFromVarDecl: Bool { bridged.MoveValue_isFromVarDecl() }
 }
@@ -1253,7 +1257,7 @@ extension BorrowIntroducingInstruction {
 final public class BeginBorrowInst : SingleValueInstruction, UnaryInstruction, BorrowIntroducingInstruction {
   public var borrowedValue: Value { operand.value }
 
-  public var isLexical: Bool { bridged.BeginBorrow_isLexical() }
+  public override var isLexical: Bool { bridged.BeginBorrow_isLexical() }
   public var hasPointerEscape: Bool { bridged.BeginBorrow_hasPointerEscape() }
   public var isFromVarDecl: Bool { bridged.BeginBorrow_isFromVarDecl() }
 

SwiftCompilerSources/Sources/SIL/Value.swift

@@ -37,6 +37,8 @@ public protocol Value : AnyObject, CustomStringConvertible {
 
   /// True if the value has a trivial type which is and does not contain a Builtin.RawPointer.
   var hasTrivialNonPointerType: Bool { get }
+
+  var isLexical: Bool { get }
 }
 
 public enum Ownership {
@@ -269,6 +271,8 @@ public final class Undef : Value {
   /// Undef has not parent function, therefore the default `hasTrivialNonPointerType` does not work.
   /// Return the conservative default in this case.
   public var hasTrivialNonPointerType: Bool { false }
+
+  public var isLexical: Bool { false }
 }
 
 final class PlaceholderValue : Value {
@@ -278,6 +282,8 @@ final class PlaceholderValue : Value {
     fatalError("PlaceholderValue has no defining block")
   }
 
+  public var isLexical: Bool { false }
+
   public var parentFunction: Function { bridged.PlaceholderValue_getParentFunction().function }
 }
 

include/swift/SIL/SILBridging.h

@@ -865,6 +865,7 @@ struct BridgedArgument {
   BRIDGED_INLINE swift::SILArgument * _Nonnull getArgument() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock getParent() const;
   BRIDGED_INLINE bool isReborrow() const;
+  BRIDGED_INLINE bool FunctionArgument_isLexical() const;
   BRIDGED_INLINE void setReborrow(bool reborrow) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE OptionalBridgedDeclObj getVarDecl() const;
   BRIDGED_INLINE void copyFlags(BridgedArgument fromArgument) const;

include/swift/SIL/SILBridgingImpl.h

@@ -676,6 +676,10 @@ void BridgedArgument::setReborrow(bool reborrow) const {
   getArgument()->setReborrow(reborrow);
 }
 
+bool BridgedArgument::FunctionArgument_isLexical() const {
+  return llvm::cast<swift::SILFunctionArgument>(getArgument())->getLifetime().isLexical();
+}
+
 OptionalBridgedDeclObj BridgedArgument::getVarDecl() const {
   return {llvm::dyn_cast_or_null<swift::VarDecl>(getArgument()->getDecl())};
 }