Change GetNumChildren()/CalculateNumChildren() methods return llvm::Expected (#84219)

Change GetNumChildren()/CalculateNumChildren() methods return
llvm::Expected

This is an NFC change that does not yet add any error handling or change
any code to return any errors.

This is the second big change in the patch series started with
https://github.com/llvm/llvm-project/pull/83501

A follow-up PR will wire up error handling.

1 files changed, 12 insertions, 5 deletions

diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibStdcpp.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibStdcpp.cpp
index 5abb3d5..86bb575 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibStdcpp.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibStdcpp.cpp
@@ -43,7 +43,7 @@ class LibstdcppMapIteratorSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
 public:
   explicit LibstdcppMapIteratorSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
 
-  uint32_t CalculateNumChildren() override;
+  llvm::Expected<uint32_t> CalculateNumChildren() override;
 
   lldb::ValueObjectSP GetChildAtIndex(uint32_t idx) override;
 
@@ -64,7 +64,7 @@ class LibStdcppSharedPtrSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
 public:
   explicit LibStdcppSharedPtrSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
 
-  uint32_t CalculateNumChildren() override;
+  llvm::Expected<uint32_t> CalculateNumChildren() override;
 
   lldb::ValueObjectSP GetChildAtIndex(uint32_t idx) override;
 
@@ -132,7 +132,8 @@ lldb::ChildCacheState LibstdcppMapIteratorSyntheticFrontEnd::Update() {
   return lldb::ChildCacheState::eReuse;
 }
 
-uint32_t LibstdcppMapIteratorSyntheticFrontEnd::CalculateNumChildren() {
+llvm::Expected<uint32_t>
+LibstdcppMapIteratorSyntheticFrontEnd::CalculateNumChildren() {
   return 2;
 }
 
@@ -219,7 +220,10 @@ lldb::ChildCacheState VectorIteratorSyntheticFrontEnd::Update() {
   return lldb::ChildCacheState::eRefetch;
 }
 
-uint32_t VectorIteratorSyntheticFrontEnd::CalculateNumChildren() { return 1; }
+llvm::Expected<uint32_t>
+VectorIteratorSyntheticFrontEnd::CalculateNumChildren() {
+  return 1;
+}
 
 lldb::ValueObjectSP
 VectorIteratorSyntheticFrontEnd::GetChildAtIndex(uint32_t idx) {
@@ -371,7 +375,10 @@ LibStdcppSharedPtrSyntheticFrontEnd::LibStdcppSharedPtrSyntheticFrontEnd(
     Update();
 }
 
-uint32_t LibStdcppSharedPtrSyntheticFrontEnd::CalculateNumChildren() { return 1; }
+llvm::Expected<uint32_t>
+LibStdcppSharedPtrSyntheticFrontEnd::CalculateNumChildren() {
+  return 1;
+}
 
 lldb::ValueObjectSP
 LibStdcppSharedPtrSyntheticFrontEnd::GetChildAtIndex(uint32_t idx) {