[Lldb-commits] [lldb] [lldb][TypeSystemClang] Fix enum signedness in CompleteEnumType (PR #125203)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

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Author: Michael Buch (Michael137)

<details>
<summary>Changes</summary>

I tried using `CompleteEnumType` to replace some duplicated code in `DWARFASTParserClang::ParseEnum` but tests started failing.

`CompleteEnumType` parses/attaches the child enumerators using the signedness it got from `CompilerType::IsIntegerType`. However, this would only report the correct signedness for builtin integer types (never for `clang::EnumType`s). We have a different API for that in `CompilerType::IsIntegerOrEnumerationType` which could've been used there instead. This patch calls `IsEnumerationIntegerTypeSigned` to determine signedness because we always pass an enum type into `CompleteEnumType` anyway.

Based on git history this has been the case for a long time, but possibly never caused issues because `ParseEnum` was completing the definition manually instead of through `CompleteEnumType`.

I couldn't find a good way to test `CompleteEnumType` on its own because it expects an enum type to be passed to it, which only gets created in `ParseEnum` (at which point we already call `CompleteEnumType`). The only other place we call `CompleteEnumType` at is in [`CompleteTypeFromDWARF`](https://github.com/llvm/llvm-project/blob/466217eb0334d467ec8e9b96c52ee988aaadc389/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp#L2260-L2262). Though I think we don't actually ever end up calling into that codepath because we eagerly complete enum definitions. Maybe we can remove that call to `CompleteEnumType` in a follow-up.

---
Full diff: https://github.com/llvm/llvm-project/pull/125203.diff


1 Files Affected:

- (modified) lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp (+6-14) 


``````````diff
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
index 6602dd763ba6930..ee99fd6f16cc44d 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
@@ -1020,15 +1020,7 @@ TypeSP DWARFASTParserClang::ParseEnum(const SymbolContext &sc,
   }
 
 
-  if (TypeSystemClang::StartTagDeclarationDefinition(clang_type)) {
-    if (def_die.HasChildren()) {
-      bool is_signed = false;
-      enumerator_clang_type.IsIntegerType(is_signed);
-      ParseChildEnumerators(clang_type, is_signed,
-                            type_sp->GetByteSize(nullptr).value_or(0), def_die);
-    }
-    TypeSystemClang::CompleteTagDeclarationDefinition(clang_type);
-  } else {
+  if (!CompleteEnumType(def_die, type_sp.get(), clang_type)) {
     dwarf->GetObjectFile()->GetModule()->ReportError(
         "DWARF DIE at {0:x16} named \"{1}\" was not able to start its "
         "definition.\nPlease file a bug and attach the file at the "
@@ -2221,13 +2213,13 @@ bool DWARFASTParserClang::CompleteRecordType(const DWARFDIE &die,
 bool DWARFASTParserClang::CompleteEnumType(const DWARFDIE &die,
                                            lldb_private::Type *type,
                                            const CompilerType &clang_type) {
+  assert(clang_type.IsEnumerationType());
+
   if (TypeSystemClang::StartTagDeclarationDefinition(clang_type)) {
-    if (die.HasChildren()) {
-      bool is_signed = false;
-      clang_type.IsIntegerType(is_signed);
-      ParseChildEnumerators(clang_type, is_signed,
+    if (die.HasChildren())
+      ParseChildEnumerators(clang_type, clang_type.IsEnumerationIntegerTypeSigned(),
                             type->GetByteSize(nullptr).value_or(0), die);
-    }
+
     TypeSystemClang::CompleteTagDeclarationDefinition(clang_type);
   }
   return (bool)clang_type;

``````````

</details>


https://github.com/llvm/llvm-project/pull/125203