[lldb][TypeSystemClang] Pass around enum value as uint64_t (#125244)

The `DWARFASTParserClang` reads enum values as `int64_t`s regardless of
the enumerators signedness. Then we pass it to
`AddEnumerationValueToEnumerationType` and only then do we create an
`APSInt` from it. However, there are other places where we read/pass
around the enum value as unsigned. This patch makes sure we consistently
use the same integer type for the enum value and let `APSInt` take care
of signedness. This shouldn't have any observable effect.

Author: Michael137

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp

@@ -2321,8 +2321,7 @@ size_t DWARFASTParserClang::ParseChildEnumerators(
       continue;
 
     const char *name = nullptr;
-    bool got_value = false;
-    int64_t enum_value = 0;
+    std::optional<uint64_t> enum_value;
     Declaration decl;
 
     for (size_t i = 0; i < attributes.Size(); ++i) {
@@ -2331,7 +2330,6 @@ size_t DWARFASTParserClang::ParseChildEnumerators(
       if (attributes.ExtractFormValueAtIndex(i, form_value)) {
         switch (attr) {
         case DW_AT_const_value:
-          got_value = true;
           if (is_signed)
             enum_value = form_value.Signed();
           else
@@ -2360,9 +2358,9 @@ size_t DWARFASTParserClang::ParseChildEnumerators(
       }
     }
 
-    if (name && name[0] && got_value) {
+    if (name && name[0] && enum_value) {
       m_ast.AddEnumerationValueToEnumerationType(
-          clang_type, decl, name, enum_value, enumerator_byte_size * 8);
+          clang_type, decl, name, *enum_value, enumerator_byte_size * 8);
       ++enumerators_added;
     }
   }

lldb/source/Plugins/SymbolFile/PDB/PDBASTParser.cpp

@@ -1155,7 +1155,7 @@ bool PDBASTParser::AddEnumValue(CompilerType enum_type,
   Variant v = enum_value.getValue();
   std::string name =
       std::string(MSVCUndecoratedNameParser::DropScope(enum_value.getName()));
-  int64_t raw_value;
+  uint64_t raw_value;
   switch (v.Type) {
   case PDB_VariantType::Int8:
     raw_value = v.Value.Int8;

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp

@@ -8541,12 +8541,10 @@ clang::EnumConstantDecl *TypeSystemClang::AddEnumerationValueToEnumerationType(
 
 clang::EnumConstantDecl *TypeSystemClang::AddEnumerationValueToEnumerationType(
     const CompilerType &enum_type, const Declaration &decl, const char *name,
-    int64_t enum_value, uint32_t enum_value_bit_size) {
-  CompilerType underlying_type = GetEnumerationIntegerType(enum_type);
-  bool is_signed = false;
-  underlying_type.IsIntegerType(is_signed);
-
-  llvm::APSInt value(enum_value_bit_size, !is_signed);
+    uint64_t enum_value, uint32_t enum_value_bit_size) {
+  assert(enum_type.IsEnumerationType());
+  llvm::APSInt value(enum_value_bit_size,
+                     !enum_type.IsEnumerationIntegerTypeSigned());
   value = enum_value;
 
   return AddEnumerationValueToEnumerationType(enum_type, decl, name, value);

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h

@@ -1040,7 +1040,7 @@ class TypeSystemClang : public TypeSystem {
   // Modifying Enumeration types
   clang::EnumConstantDecl *AddEnumerationValueToEnumerationType(
       const CompilerType &enum_type, const Declaration &decl, const char *name,
-      int64_t enum_value, uint32_t enum_value_bit_size);
+      uint64_t enum_value, uint32_t enum_value_bit_size);
   clang::EnumConstantDecl *AddEnumerationValueToEnumerationType(
       const CompilerType &enum_type, const Declaration &decl, const char *name,
       const llvm::APSInt &value);