[sil] Also give Placeholder a parent SILFunction.

Author: gottesmm

include/swift/SIL/SILValue.h

@@ -1592,16 +1592,20 @@ inline llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, SILValue V) {
 
 /// Used internally in e.g. the SIL parser and deserializer to handle forward-
 /// referenced values.
+///
 /// A PlaceholderValue must not appear in valid SIL.
 class PlaceholderValue : public ValueBase {
+  SILFunction *parentFunction;
   static int numPlaceholderValuesAlive;
 
 public:
-  PlaceholderValue(SILType type);
+  PlaceholderValue(SILFunction *parentFunction, SILType type);
   ~PlaceholderValue();
 
   static int getNumPlaceholderValuesAlive() { return numPlaceholderValuesAlive; }
 
+  SILFunction *getParent() const { return parentFunction; }
+
   static bool classof(const SILArgument *) = delete;
   static bool classof(const SILInstruction *) = delete;
   static bool classof(SILNodePointer node) {

lib/SIL/IR/SILModule.cpp

@@ -680,7 +680,8 @@ SILValue SILModule::getRootLocalArchetypeDef(CanLocalArchetypeType archetype,
   SILValue &def = RootLocalArchetypeDefs[{archetype, inFunction}];
   if (!def) {
     numUnresolvedLocalArchetypes++;
-    def = ::new PlaceholderValue(SILType::getPrimitiveAddressType(archetype));
+    def = ::new PlaceholderValue(inFunction,
+                                 SILType::getPrimitiveAddressType(archetype));
   }
 
   return def;

lib/SIL/IR/SILValue.cpp

@@ -224,6 +224,9 @@ SILFunction *SILNode::getFunction() const {
   if (auto *undef = dyn_cast<SILUndef>(this))
     return undef->getParent();
 
+  if (auto *placeHolder = dyn_cast<PlaceholderValue>(this))
+    return placeHolder->getParent();
+
   return nullptr;
 }
 
@@ -540,8 +543,8 @@ llvm::raw_ostream &swift::operator<<(llvm::raw_ostream &os,
 
 int PlaceholderValue::numPlaceholderValuesAlive = 0;
 
-PlaceholderValue::PlaceholderValue(SILType type)
-      : ValueBase(ValueKind::PlaceholderValue, type) {
+PlaceholderValue::PlaceholderValue(SILFunction *fn, SILType type)
+    : ValueBase(ValueKind::PlaceholderValue, type), parentFunction(fn) {
   numPlaceholderValuesAlive++;
 }
 

lib/SIL/Parser/ParseSIL.cpp

@@ -376,7 +376,7 @@ SILValue SILParser::getLocalValue(UnresolvedValueName Name, SILType Type,
   // it until we see a real definition.
   ForwardRefLocalValues[Name.Name] = Name.NameLoc;
 
-  Entry = ::new PlaceholderValue(Type);
+  Entry = ::new PlaceholderValue(&B.getFunction(), Type);
   return Entry;
 }
 

lib/Serialization/DeserializeSIL.cpp

@@ -319,7 +319,7 @@ SILValue SILDeserializer::getLocalValue(SILFunction *inContext, ValueID Id,
   if (!Entry) {
     // Otherwise, this is a forward reference.  Create a dummy node to represent
     // it until we see a real definition.
-    Entry = ::new PlaceholderValue(Type);
+    Entry = ::new PlaceholderValue(inContext, Type);
   }
   // If this value was already defined, check it to make sure types match.
   assert(Entry->getType() == Type && "Value Type mismatch?");