Swift SIL: add MultipleValueInstructionResult.index

And make DestructureStructInst and DestructureTupleInst a UnaryInstruction

Author: eeckstein

SwiftCompilerSources/Sources/SIL/Instruction.swift

@@ -144,6 +144,8 @@ public final class MultipleValueInstructionResult : Value {
 
   public var definingInstruction: Instruction? { instruction }
 
+  public var index: Int { MultiValueInstResult_getIndex(bridged) }
+
   var bridged: BridgedMultiValueResult {
     BridgedMultiValueResult(obj: SwiftObject(self))
   }
@@ -568,10 +570,10 @@ final public class BeginCOWMutationInst : MultipleValueInstruction,
   public var bufferResult: Value { return getResult(index: 1) }
 }
 
-final public class DestructureStructInst : MultipleValueInstruction {
+final public class DestructureStructInst : MultipleValueInstruction, UnaryInstruction {
 }
 
-final public class DestructureTupleInst : MultipleValueInstruction {
+final public class DestructureTupleInst : MultipleValueInstruction, UnaryInstruction {
 }
 
 final public class BeginApplyInst : MultipleValueInstruction, FullApplySite {

include/swift/SIL/SILBridging.h

@@ -247,6 +247,7 @@ BridgedMemoryBehavior SILInstruction_getMemBehavior(BridgedInstruction inst);
 bool SILInstruction_mayRelease(BridgedInstruction inst);
 
 BridgedInstruction MultiValueInstResult_getParent(BridgedMultiValueResult result);
+SwiftInt MultiValueInstResult_getIndex(BridgedMultiValueResult result);
 SwiftInt MultipleValueInstruction_getNumResults(BridgedInstruction inst);
 BridgedMultiValueResult
   MultipleValueInstruction_getResult(BridgedInstruction inst, SwiftInt index);

lib/SIL/Utils/SILBridging.cpp

@@ -520,6 +520,11 @@ BridgedInstruction MultiValueInstResult_getParent(BridgedMultiValueResult result
   return {static_cast<MultipleValueInstructionResult *>(result.obj)->getParent()};
 }
 
+SwiftInt MultiValueInstResult_getIndex(BridgedMultiValueResult result) {
+  auto *rs = static_cast<MultipleValueInstructionResult *>(result.obj);
+  return (SwiftInt)rs->getIndex();
+}
+
 SwiftInt MultipleValueInstruction_getNumResults(BridgedInstruction inst) {
   return castToInst<MultipleValueInstruction>(inst)->getNumResults();
 }