SIL: add the Argument.set(reborrow:) and Argument.hasBorrowEndingUse APIs

Author: eeckstein

SwiftCompilerSources/Sources/Optimizer/PassManager/Context.swift

@@ -628,6 +628,13 @@ extension BasicBlock {
   }
 }
 
+extension Argument {
+  func set(reborrow: Bool, _ context: some MutatingContext) {
+    context.notifyInstructionsChanged()
+    bridged.setReborrow(reborrow)
+  }
+}
+
 extension AllocRefInstBase {
   func setIsStackAllocatable(_ context: some MutatingContext) {
     context.notifyInstructionsChanged()

SwiftCompilerSources/Sources/SIL/Argument.swift

@@ -24,8 +24,8 @@ public class Argument : Value, Hashable {
     return bridged.getParent().block
   }
 
-  var bridged: BridgedArgument { BridgedArgument(obj: SwiftObject(self)) }
-  
+  public var bridged: BridgedArgument { BridgedArgument(obj: SwiftObject(self)) }
+
   public var index: Int {
     return parentBlock.arguments.firstIndex(of: self)!
   }
@@ -165,6 +165,18 @@ public struct Phi {
     return nil
   }
 
+  // Returns true if the phi has an end_borrow or a re-borrowing branch as user.
+  // This should be consistent with the `isReborrow` flag.
+  public var hasBorrowEndingUse: Bool {
+    let phiValue: Value = borrowedFrom ?? value
+    return phiValue.uses.contains {
+      switch $0.ownership {
+        case .endBorrow, .reborrow: return true
+        default:                    return false
+      }
+    }
+  }
+
   public static func ==(lhs: Phi, rhs: Phi) -> Bool {
     lhs.value === rhs.value
   }

include/swift/SIL/SILBridging.h

@@ -864,6 +864,7 @@ struct BridgedArgument {
   BRIDGED_INLINE swift::SILArgument * _Nonnull getArgument() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedBasicBlock getParent() const;
   BRIDGED_INLINE bool isReborrow() const;
+  BRIDGED_INLINE 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

@@ -672,6 +672,9 @@ BridgedBasicBlock BridgedArgument::getParent() const {
 }
 
 bool BridgedArgument::isReborrow() const { return getArgument()->isReborrow(); }
+void BridgedArgument::setReborrow(bool reborrow) const {
+  getArgument()->setReborrow(reborrow);
+}
 
 OptionalBridgedDeclObj BridgedArgument::getVarDecl() const {
   return {llvm::dyn_cast_or_null<swift::VarDecl>(getArgument()->getDecl())};