ApplySite::getPseudoResult

This returns the fake tuple value for either an apply or
try_apply. This is not actually a result. It is composed of the
results.

Author: atrick

include/swift/SIL/ApplySite.h

@@ -580,18 +580,19 @@ class FullApplySite : public ApplySite {
     return getSubstCalleeConv().hasIndirectSILResults();
   }
 
-  /// If our apply site has a single direct result SILValue, return that
-  /// SILValue. Return SILValue() otherwise.
+  /// Get the SIL value that represents all of the given call's results. For a
+  /// single direct result, returns the result. For multiple results, returns a
+  /// fake tuple value. The tuple has no storage of its own. The real results
+  /// must be extracted from it.
   ///
-  /// This means that:
+  /// For ApplyInst, returns the single-value instruction itself.
   ///
-  /// 1. If we have an ApplyInst, we just visit the apply.
-  /// 2. If we have a TryApplyInst, we visit the first argument of the normal
-  ///    block.
-  /// 3. If we have a BeginApplyInst, we return SILValue() since the begin_apply
-  ///    yields values instead of returning them. A returned value should only
-  ///    be valid after a full apply site has completely finished executing.
-  SILValue getSingleDirectResult() const {
+  /// For TryApplyInst returns the continuation block argument.
+  ///
+  /// For BeginApplyInst, returns an invalid value. For coroutines, there is no
+  /// single value representing all results. Yielded values are generally
+  /// handled differently since they have the convention of incoming arguments.
+  SILValue getPseudoResult() const {
     switch (getKind()) {
     case FullApplySiteKind::ApplyInst:
       return SILValue(cast<ApplyInst>(getInstruction()));

lib/SILOptimizer/Utils/Generics.cpp

@@ -2244,8 +2244,8 @@ SILFunction *ReabstractionThunkGenerator::createThunk() {
       Arguments.push_back(NewArg);
     }
     FullApplySite ApplySite = createReabstractionThunkApply(Builder);
-    SILValue ReturnValue = ApplySite.getSingleDirectResult();
-    assert(ReturnValue && "getSingleDirectResult out of sync with ApplySite?!");
+    SILValue ReturnValue = ApplySite.getPseudoResult();
+    assert(ReturnValue && "getPseudoResult out of sync with ApplySite?!");
     Builder.createReturn(Loc, ReturnValue);
 
     return Thunk;
@@ -2257,8 +2257,8 @@ SILFunction *ReabstractionThunkGenerator::createThunk() {
 
   FullApplySite ApplySite = createReabstractionThunkApply(Builder);
 
-  SILValue ReturnValue = ApplySite.getSingleDirectResult();
-  assert(ReturnValue && "getSingleDirectResult out of sync with ApplySite?!");
+  SILValue ReturnValue = ApplySite.getPseudoResult();
+  assert(ReturnValue && "getPseudoResult out of sync with ApplySite?!");
 
   if (ReturnValueAddr) {
     // Need to store the direct results to the original indirect address.