Add getLifetimeDependenceInfoOrNull to FunctionType/GenericFunctionType/AnyFunctionType

Author: meg-gupta

include/swift/AST/Types.h

@@ -3433,7 +3433,14 @@ class AnyFunctionType : public TypeBase {
   Type getGlobalActor() const;
   Type getThrownError() const;
 
-  LifetimeDependenceInfo getLifetimeDependenceInfo() const;
+  const LifetimeDependenceInfo *getLifetimeDependenceInfoOrNull() const;
+
+  LifetimeDependenceInfo getLifetimeDependenceInfo() const {
+    if (auto *depInfo = getLifetimeDependenceInfoOrNull()) {
+      return *depInfo;
+    }
+    return LifetimeDependenceInfo();
+  }
 
   FunctionTypeIsolation getIsolation() const {
     if (hasExtInfo())
@@ -3765,14 +3772,19 @@ class FunctionType final
     return getTrailingObjects<Type>()[hasGlobalActor()];
   }
 
-  LifetimeDependenceInfo getLifetimeDependenceInfo() const {
-    if (!hasLifetimeDependenceInfo()) {
-      return LifetimeDependenceInfo();
+  inline LifetimeDependenceInfo getLifetimeDependenceInfo() const {
+    if (auto *depInfo = getLifetimeDependenceInfoOrNull()) {
+      return *depInfo;
     }
+    return LifetimeDependenceInfo();
+  }
+
+  /// Returns nullptr for an empty dependence list.
+  const LifetimeDependenceInfo *getLifetimeDependenceInfoOrNull() const {
     auto *info = getTrailingObjects<LifetimeDependenceInfo>();
     assert(!info->empty() && "If the LifetimeDependenceInfo was empty, we "
                              "shouldn't have stored it.");
-    return *info;
+    return info;
   }
 
   void Profile(llvm::FoldingSetNodeID &ID) {
@@ -3914,14 +3926,19 @@ class GenericFunctionType final
     return getTrailingObjects<Type>()[hasGlobalActor()];
   }
 
-  LifetimeDependenceInfo getLifetimeDependenceInfo() const {
-    if (!hasLifetimeDependenceInfo()) {
-      return LifetimeDependenceInfo();
+  inline LifetimeDependenceInfo getLifetimeDependenceInfo() const {
+    if (auto *depInfo = getLifetimeDependenceInfoOrNull()) {
+      return *depInfo;
     }
+    return LifetimeDependenceInfo();
+  }
+
+  /// Returns nullptr for an empty dependence list.
+  const LifetimeDependenceInfo *getLifetimeDependenceInfoOrNull() const {
     auto *info = getTrailingObjects<LifetimeDependenceInfo>();
     assert(!info->empty() && "If the LifetimeDependenceInfo was empty, we "
                              "shouldn't have stored it.");
-    return *info;
+    return info;
   }
 
   /// Retrieve the generic signature of this function type.

lib/AST/Type.cpp

@@ -3896,12 +3896,13 @@ Type AnyFunctionType::getGlobalActor() const {
   }
 }
 
-LifetimeDependenceInfo AnyFunctionType::getLifetimeDependenceInfo() const {
+const LifetimeDependenceInfo *
+AnyFunctionType::getLifetimeDependenceInfoOrNull() const {
   switch (getKind()) {
   case TypeKind::Function:
-    return cast<FunctionType>(this)->getLifetimeDependenceInfo();
+    return cast<FunctionType>(this)->getLifetimeDependenceInfoOrNull();
   case TypeKind::GenericFunction:
-    return cast<GenericFunctionType>(this)->getLifetimeDependenceInfo();
+    return cast<GenericFunctionType>(this)->getLifetimeDependenceInfoOrNull();
 
   default:
     llvm_unreachable("Illegal type kind for AnyFunctionType.");