[NFC] Extract the parts of TupleElementAddressGenerator that just deal

with walking the tuple so that they can be used without an address.

Author: rjmccall

lib/SILGen/SILGenPoly.cpp

@@ -2124,18 +2124,18 @@ TupleElementAddressGenerator::projectElementAddress(SILGenFunction &SGF,
       SGF.B.createTupleElementAddr(loc, tupleAddr, eltIndex, eltTy));
   } else if (isSubstPackExpansion()) {
     eltValue = cloner.cloneForTuplePackExpansionComponent(tupleAddr,
-                                                         inducedPackType,
-                                                         eltIndex);
+                                                          getInducedPackType(),
+                                                          eltIndex);
   } else {
     auto packIndex =
-      SGF.B.createScalarPackIndex(loc, eltIndex, inducedPackType);
+      SGF.B.createScalarPackIndex(loc, eltIndex, getInducedPackType());
     auto eltAddr =
       SGF.B.createTuplePackElementAddr(loc, packIndex, tupleAddr, eltTy);
     eltValue = cloner.clone(eltAddr);
   }
 
   tupleValue = cloner.cloneForRemainingTupleComponents(tupleAddr,
-                                                       inducedPackType,
+                                                       getInducedPackTypeIfPresent(),
                                                        eltIndex + 1);
   this->tupleAddr = tupleValue;
 

lib/SILGen/TupleGenerators.h

@@ -279,12 +279,9 @@ class ExpandedTupleInputGenerator {
                         ManagedValue elt);
 };
 
-/// A generator for visiting the addresses of the elements of
-/// a tuple.  Unlike the other tuple generators, this does not
-/// require the original abstraction pattern to be a tuple pattern:
-/// like forEachExpandedTupleElement, it permits an opaque
-/// abstraction pattern.
-class TupleElementAddressGenerator {
+/// A generator for visiting the substituted elements of a tuple
+/// (unlike TupleElementGenerator, which visits the orig elements).
+class TupleSubstElementGenerator {
   struct OpaquePatternStorage {
     AbstractionPattern origType;
     CanTupleType substType;
@@ -297,9 +294,6 @@ class TupleElementAddressGenerator {
   }
   ExternalUnion<bool, Members, getIndexForKind> origElt;
 
-  /// The address of the tuple value.
-  ManagedValue tupleAddr;
-
   /// If the substituted tuple type contains pack expansions, this is
   /// the induced pack type for the element sequence.
   CanPackType inducedPackType;
@@ -341,12 +335,9 @@ class TupleElementAddressGenerator {
   }
 
 public:
-  TupleElementAddressGenerator(const ASTContext &ctx,
-                               ManagedValue tupleAddr,
-                               AbstractionPattern origType,
-                               CanTupleType substType)
-      : tupleAddr(tupleAddr) {
-
+  TupleSubstElementGenerator(const ASTContext &ctx,
+                             AbstractionPattern origType,
+                             CanTupleType substType) {
     if (substType->containsPackExpansionType()) {
       inducedPackType = CanPackType::get(ctx, substType.getElementTypes());
     }
@@ -420,6 +411,13 @@ class TupleElementAddressGenerator {
     return inducedPackType;
   }
 
+  /// Return the induced pack type if the substituted tuple contains
+  /// pack expansions or null if it does not.  Suitable for use with
+  /// e.g. enterDestroyRemainingTupleComponentsCleanup.
+  CanPackType getInducedPackTypeIfPresent() const {
+    return inducedPackType;
+  }
+
   /// Given that we just processed an input, advance to the next,
   /// if there is on.
   ///
@@ -444,6 +442,26 @@ class TupleElementAddressGenerator {
       gen.finish();
     }
   }
+};
+
+/// A generator for visiting the addresses of the elements of
+/// a tuple.  Unlike the other tuple generators, this does not
+/// require the original abstraction pattern to be a tuple pattern:
+/// like forEachExpandedTupleElement, it permits an opaque
+/// abstraction pattern.
+class TupleElementAddressGenerator : public TupleSubstElementGenerator {
+  /// The address of the tuple value.
+  ManagedValue tupleAddr;
+
+public:
+  TupleElementAddressGenerator(const ASTContext &ctx,
+                               ManagedValue tupleAddr,
+                               AbstractionPattern origType,
+                               CanTupleType substType)
+    : TupleSubstElementGenerator(ctx, origType, substType),
+      tupleAddr(tupleAddr) {
+    assert(tupleAddr.getType().isAddress());
+  }
 
   /// Project out the current tuple element.  Call this exactly once
   /// per element.