[Lldb-commits] [clang] [lldb] [lldb] Analyze enum promotion type during parsing (PR #115005)

[Michael Buch via lldb-commits]

================
@@ -2367,11 +2369,38 @@ size_t DWARFASTParserClang::ParseChildEnumerators(
     }
 
     if (name && name[0] && got_value) {
-      m_ast.AddEnumerationValueToEnumerationType(
+      auto ECD = m_ast.AddEnumerationValueToEnumerationType(
           clang_type, decl, name, enum_value, enumerator_byte_size * 8);
       ++enumerators_added;
+
+      llvm::APSInt InitVal = ECD->getInitVal();
+      // Keep track of the size of positive and negative values.
+      if (InitVal.isUnsigned() || InitVal.isNonNegative()) {
+        // If the enumerator is zero that should still be counted as a positive
+        // bit since we need a bit to store the value zero.
+        unsigned ActiveBits = InitVal.getActiveBits();
+        NumPositiveBits = std::max({NumPositiveBits, ActiveBits, 1u});
+      } else {
+        NumNegativeBits =
+            std::max(NumNegativeBits, (unsigned)InitVal.getSignificantBits());
+      }
     }
   }
+
+  if (!NumPositiveBits && !NumNegativeBits)
+    NumPositiveBits = 1;
+
+  clang::EnumDecl *enum_decl =
+      ClangUtil::GetQualType(clang_type)->getAs<clang::EnumType>()->getDecl();
+  enum_decl->setNumPositiveBits(NumPositiveBits);
+  enum_decl->setNumNegativeBits(NumNegativeBits);
+
+  clang::QualType BestPromotionType;
+  clang::QualType BestType;
+  m_ast.getASTContext().computeBestEnumTypes(
+      false, NumNegativeBits, NumPositiveBits, BestType, BestPromotionType);
----------------
Michael137 wrote:

```suggestion
      /*IsPacked=*/false, NumNegativeBits, NumPositiveBits, BestType, BestPromotionType);
```

https://github.com/llvm/llvm-project/pull/115005