[lldb] Upgrade CompilerType::GetBitSize to return llvm::Expected (#129601)

This patch pushes the error handling boundary for the GetBitSize()
methods from Runtime into the Type and CompilerType APIs. This makes it
easier to diagnose problems thanks to more meaningful error messages
being available. GetBitSize() is often the first thing LLDB asks about a
type, so this method is particularly important for a better user
experience.

rdar://145667239

Author: adrian-prantl

lldb/include/lldb/Expression/ExpressionVariable.h

@@ -33,7 +33,7 @@ class ExpressionVariable
 
   virtual ~ExpressionVariable() = default;
 
-  std::optional<uint64_t> GetByteSize() { return m_frozen_sp->GetByteSize(); }
+  llvm::Expected<uint64_t> GetByteSize() { return m_frozen_sp->GetByteSize(); }
 
   ConstString GetName() { return m_frozen_sp->GetName(); }
 

lldb/include/lldb/Symbol/CompilerType.h

@@ -391,9 +391,9 @@ class CompilerType {
   struct IntegralTemplateArgument;
 
   /// Return the size of the type in bytes.
-  std::optional<uint64_t> GetByteSize(ExecutionContextScope *exe_scope) const;
+  llvm::Expected<uint64_t> GetByteSize(ExecutionContextScope *exe_scope) const;
   /// Return the size of the type in bits.
-  std::optional<uint64_t> GetBitSize(ExecutionContextScope *exe_scope) const;
+  llvm::Expected<uint64_t> GetBitSize(ExecutionContextScope *exe_scope) const;
 
   lldb::Encoding GetEncoding(uint64_t &count) const;
 

lldb/include/lldb/Symbol/Type.h

@@ -480,7 +480,7 @@ class Type : public std::enable_shared_from_this<Type>, public UserID {
 
   ConstString GetBaseName();
 
-  std::optional<uint64_t> GetByteSize(ExecutionContextScope *exe_scope);
+  llvm::Expected<uint64_t> GetByteSize(ExecutionContextScope *exe_scope);
 
   llvm::Expected<uint32_t> GetNumChildren(bool omit_empty_base_classes);
 

lldb/include/lldb/Symbol/TypeSystem.h

@@ -312,7 +312,7 @@ class TypeSystem : public PluginInterface,
 
   virtual const llvm::fltSemantics &GetFloatTypeSemantics(size_t byte_size) = 0;
 
-  virtual std::optional<uint64_t>
+  virtual llvm::Expected<uint64_t>
   GetBitSize(lldb::opaque_compiler_type_t type,
              ExecutionContextScope *exe_scope) = 0;
 

lldb/include/lldb/Target/StackFrameRecognizer.h

@@ -180,7 +180,7 @@ class ValueObjectRecognizerSynthesizedValue : public ValueObject {
     SetName(parent.GetName());
   }
 
-  std::optional<uint64_t> GetByteSize() override {
+  llvm::Expected<uint64_t> GetByteSize() override {
     return m_parent->GetByteSize();
   }
   lldb::ValueType GetValueType() const override { return m_type; }

lldb/include/lldb/ValueObject/ValueObject.h

@@ -357,7 +357,7 @@ class ValueObject {
   virtual bool CanProvideValue();
 
   // Subclasses must implement the functions below.
-  virtual std::optional<uint64_t> GetByteSize() = 0;
+  virtual llvm::Expected<uint64_t> GetByteSize() = 0;
 
   virtual lldb::ValueType GetValueType() const = 0;
 

lldb/include/lldb/ValueObject/ValueObjectCast.h

@@ -30,7 +30,7 @@ class ValueObjectCast : public ValueObject {
   static lldb::ValueObjectSP Create(ValueObject &parent, ConstString name,
                                     const CompilerType &cast_type);
 
-  std::optional<uint64_t> GetByteSize() override;
+  llvm::Expected<uint64_t> GetByteSize() override;
 
   llvm::Expected<uint32_t> CalculateNumChildren(uint32_t max) override;
 

lldb/include/lldb/ValueObject/ValueObjectChild.h

@@ -29,7 +29,7 @@ class ValueObjectChild : public ValueObject {
 public:
   ~ValueObjectChild() override;
 
-  std::optional<uint64_t> GetByteSize() override { return m_byte_size; }
+  llvm::Expected<uint64_t> GetByteSize() override { return m_byte_size; }
 
   lldb::offset_t GetByteOffset() override { return m_byte_offset; }
 

lldb/include/lldb/ValueObject/ValueObjectConstResult.h

@@ -64,7 +64,7 @@ class ValueObjectConstResult : public ValueObject {
   static lldb::ValueObjectSP Create(ExecutionContextScope *exe_scope,
                                     Status &&error);
 
-  std::optional<uint64_t> GetByteSize() override;
+  llvm::Expected<uint64_t> GetByteSize() override;
 
   lldb::ValueType GetValueType() const override;
 

lldb/include/lldb/ValueObject/ValueObjectDynamicValue.h

@@ -35,7 +35,7 @@ class ValueObjectDynamicValue : public ValueObject {
 public:
   ~ValueObjectDynamicValue() override = default;
 
-  std::optional<uint64_t> GetByteSize() override;
+  llvm::Expected<uint64_t> GetByteSize() override;
 
   ConstString GetTypeName() override;