Introduce end_cow_mutation_addr instruction

Author: meg-gupta

SwiftCompilerSources/Sources/Optimizer/TestPasses/MemBehaviorDumper.swift

@@ -63,6 +63,7 @@ private extension Instruction {
          is BeginAccessInst,
          is EndAccessInst,
          is EndCOWMutationInst,
+         is EndCOWMutationAddrInst,
          is CopyValueInst,
          is DestroyValueInst,
          is StrongReleaseInst,

SwiftCompilerSources/Sources/Optimizer/Utilities/AddressUtils.swift

@@ -131,7 +131,7 @@ extension AddressUseVisitor {
          is DestroyAddrInst, is DeallocStackInst, 
          is DeinitExistentialAddrInst,
          is IsUniqueInst, is MarkFunctionEscapeInst,
-         is PackElementSetInst:
+         is PackElementSetInst, is EndCOWMutationAddrInst:
       return leafAddressUse(of: operand)
 
     case is LoadInst, is LoadUnownedInst,  is LoadWeakInst, is ValueMetatypeInst, is ExistentialMetatypeInst,

SwiftCompilerSources/Sources/SIL/Builder.swift

@@ -575,6 +575,11 @@ public struct Builder {
     return notifyNew(endMutation.getAs(EndCOWMutationInst.self))
   }
 
+  public func createEndCOWMutationAddr(address: Value) -> EndCOWMutationAddrInst {
+    let endMutation = bridged.createEndCOWMutationAddr(address.bridged)
+    return notifyNew(endMutation.getAs(EndCOWMutationAddrInst.self))
+  }
+
   public func createMarkDependence(value: Value, base: Value, kind: MarkDependenceKind) -> MarkDependenceInst {
     let markDependence = bridged.createMarkDependence(value.bridged, base.bridged,
                                                       BridgedInstruction.MarkDependenceKind(rawValue: kind.rawValue)!)

SwiftCompilerSources/Sources/SIL/Instruction.swift

@@ -1240,6 +1240,10 @@ final public class EndCOWMutationInst : SingleValueInstruction, UnaryInstruction
   public var doKeepUnique: Bool { bridged.EndCOWMutationInst_doKeepUnique() }
 }
 
+final public class EndCOWMutationAddrInst : Instruction, UnaryInstruction {
+  public var address: Value { operand.value }
+}
+
 final public
 class ClassifyBridgeObjectInst : SingleValueInstruction, UnaryInstruction {}
 

SwiftCompilerSources/Sources/SIL/Registration.swift

@@ -215,6 +215,7 @@ public func registerSILClasses() {
   register(MoveValueInst.self)
   register(DropDeinitInst.self)
   register(EndCOWMutationInst.self)
+  register(EndCOWMutationAddrInst.self)
   register(ClassifyBridgeObjectInst.self)
   register(PartialApplyInst.self)
   register(ApplyInst.self)

docs/SIL/Instructions.md

@@ -2146,6 +2146,22 @@ not replace this reference with a not uniquely reference object.
 
 For details see [Copy-on-Write Representation](SIL.md#Copy-on-Write-Representation).
 
+### end_cow_mutation_addr
+
+```
+sil-instruction ::= 'end_cow_mutation_addr' sil-operand
+
+end_cow_mutation_addr %0 : $*T
+// %0 must be of an address $*T type
+```
+
+This instruction marks the end of mutation of an address. The address could be
+an opaque archetype, a struct, tuple or enum type and the end_cow_mutation_addr
+will apply to all members contained within it.
+It is currently only generated in cases where we maybe deriving a MutableSpan from
+`%0` since it is not possible to schedule an `end_cow_mutation` in the standard
+library automatically for Array.mutableSpan etc.
+
 ### destroy_not_escaped_closure
 
 ```

include/swift/SIL/AddressWalker.h

@@ -229,7 +229,7 @@ TransitiveAddressWalker<Impl>::walk(SILValue projectedAddress) {
         isa<PackElementSetInst>(user) || isa<PackElementGetInst>(user) ||
         isa<DeinitExistentialAddrInst>(user) || isa<LoadBorrowInst>(user) ||
         isa<TupleAddrConstructorInst>(user) || isa<DeallocPackInst>(user) ||
-        isa<MergeIsolationRegionInst>(user)) {
+        isa<MergeIsolationRegionInst>(user) || isa<EndCOWMutationAddrInst>(user)) {
       callVisitUse(op);
       continue;
     }

include/swift/SIL/SILBridging.h

@@ -1277,6 +1277,7 @@ struct BridgedBuilder{
                                           BridgedASTType::MetatypeRepresentation representation) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createEndCOWMutation(BridgedValue instance,
                                                                              bool keepUnique) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createEndCOWMutationAddr(BridgedValue instance) const;                                                                             
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedInstruction createMarkDependence(
     BridgedValue value, BridgedValue base, BridgedInstruction::MarkDependenceKind dependenceKind) const;
 

include/swift/SIL/SILBridgingImpl.h

@@ -2501,6 +2501,12 @@ BridgedInstruction BridgedBuilder::createEndCOWMutation(BridgedValue instance, b
                                            keepUnique)};
 }
 
+BridgedInstruction
+BridgedBuilder::createEndCOWMutationAddr(BridgedValue instance) const {
+  return {unbridged().createEndCOWMutationAddr(regularLoc(),
+                                               instance.getSILValue())};
+}
+
 BridgedInstruction BridgedBuilder::createMarkDependence(BridgedValue value, BridgedValue base, BridgedInstruction::MarkDependenceKind kind) const {
   return {unbridged().createMarkDependence(regularLoc(), value.getSILValue(), base.getSILValue(), swift::MarkDependenceKind(kind))};
 }

include/swift/SIL/SILBuilder.h

@@ -2383,6 +2383,11 @@ class SILBuilder {
     return insert(new (getModule()) EndCOWMutationInst(getSILDebugLocation(Loc),
                                                   operand, keepUnique));
   }
+  EndCOWMutationAddrInst *createEndCOWMutationAddr(SILLocation Loc,
+                                                   SILValue operand) {
+    return insert(new (getModule()) EndCOWMutationAddrInst(
+        getSILDebugLocation(Loc), operand));
+  }
   DestroyNotEscapedClosureInst *createDestroyNotEscapedClosure(SILLocation Loc,
                                                  SILValue operand,
                                                  unsigned VerificationType) {