[clang][Sema] Move computing best enum types to a separate function

clang/include/clang/AST/ASTContext.h

@@ -1726,6 +1726,13 @@ class ASTContext : public RefCountedBase<ASTContext> {
 
   QualType getEnumType(const EnumDecl *Decl) const;
 
+  /// Compute BestType and BestPromotionType for an enum based on the highest
+  /// number of negative and positive bits of its elements.
+  /// Returns true if enum width is too large.
+  bool computeBestEnumTypes(bool IsPacked, unsigned NumNegativeBits,
+                            unsigned NumPositiveBits, QualType &BestType,
+                            QualType &BestPromotionType);
+
   QualType
   getUnresolvedUsingType(const UnresolvedUsingTypenameDecl *Decl) const;
 

clang/lib/AST/ASTContext.cpp

@@ -5209,6 +5209,85 @@ QualType ASTContext::getEnumType(const EnumDecl *Decl) const {
   return QualType(newType, 0);
 }
 
+bool ASTContext::computeBestEnumTypes(bool IsPacked, unsigned NumNegativeBits,
+                                      unsigned NumPositiveBits,
+                                      QualType &BestType,
+                                      QualType &BestPromotionType) {
+  unsigned IntWidth = Target->getIntWidth();
+  unsigned CharWidth = Target->getCharWidth();
+  unsigned ShortWidth = Target->getShortWidth();
+  bool EnumTooLarge = false;
+  unsigned BestWidth;
+  if (NumNegativeBits) {
+    // If there is a negative value, figure out the smallest integer type (of
+    // int/long/longlong) that fits.
+    // If it's packed, check also if it fits a char or a short.
+    if (IsPacked && NumNegativeBits <= CharWidth &&
+        NumPositiveBits < CharWidth) {
+      BestType = SignedCharTy;
+      BestWidth = CharWidth;
+    } else if (IsPacked && NumNegativeBits <= ShortWidth &&
+               NumPositiveBits < ShortWidth) {
+      BestType = ShortTy;
+      BestWidth = ShortWidth;
+    } else if (NumNegativeBits <= IntWidth && NumPositiveBits < IntWidth) {
+      BestType = IntTy;
+      BestWidth = IntWidth;
+    } else {
+      BestWidth = Target->getLongWidth();
+
+      if (NumNegativeBits <= BestWidth && NumPositiveBits < BestWidth) {
+        BestType = LongTy;
+      } else {
+        BestWidth = Target->getLongLongWidth();
+
+        if (NumNegativeBits > BestWidth || NumPositiveBits >= BestWidth)
+          EnumTooLarge = true;
+        BestType = LongLongTy;
+      }
+    }
+    BestPromotionType = (BestWidth <= IntWidth ? IntTy : BestType);
+  } else {
+    // If there is no negative value, figure out the smallest type that fits
+    // all of the enumerator values.
+    // If it's packed, check also if it fits a char or a short.
+    if (IsPacked && NumPositiveBits <= CharWidth) {
+      BestType = UnsignedCharTy;
+      BestPromotionType = IntTy;
+      BestWidth = CharWidth;
+    } else if (IsPacked && NumPositiveBits <= ShortWidth) {
+      BestType = UnsignedShortTy;
+      BestPromotionType = IntTy;
+      BestWidth = ShortWidth;
+    } else if (NumPositiveBits <= IntWidth) {
+      BestType = UnsignedIntTy;
+      BestWidth = IntWidth;
+      BestPromotionType = (NumPositiveBits == BestWidth || !LangOpts.CPlusPlus)
+                              ? UnsignedIntTy
+                              : IntTy;
+    } else if (NumPositiveBits <= (BestWidth = Target->getLongWidth())) {
+      BestType = UnsignedLongTy;
+      BestPromotionType = (NumPositiveBits == BestWidth || !LangOpts.CPlusPlus)
+                              ? UnsignedLongTy
+                              : LongTy;
+    } else {
+      BestWidth = Target->getLongLongWidth();
+      if (NumPositiveBits > BestWidth) {
+        // This can happen with bit-precise integer types, but those are not
+        // allowed as the type for an enumerator per C23 6.7.2.2p4 and p12.
+        // FIXME: GCC uses __int128_t and __uint128_t for cases that fit within
+        // a 128-bit integer, we should consider doing the same.
+        EnumTooLarge = true;
+      }
+      BestType = UnsignedLongLongTy;
+      BestPromotionType = (NumPositiveBits == BestWidth || !LangOpts.CPlusPlus)
+                              ? UnsignedLongLongTy
+                              : LongLongTy;
+    }
+  }
+  return EnumTooLarge;
+}
+
 QualType ASTContext::getUnresolvedUsingType(
     const UnresolvedUsingTypenameDecl *Decl) const {
   if (Decl->TypeForDecl)

clang/lib/Sema/SemaDecl.cpp

@@ -20030,10 +20030,6 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange,
     return;
   }
 
-  unsigned IntWidth = Context.getTargetInfo().getIntWidth();
-  unsigned CharWidth = Context.getTargetInfo().getCharWidth();
-  unsigned ShortWidth = Context.getTargetInfo().getShortWidth();
-
   // Verify that all the values are okay, compute the size of the values, and
   // reverse the list.
   unsigned NumNegativeBits = 0;
@@ -20099,73 +20095,12 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange,
       BestPromotionType = BestType;
 
     BestWidth = Context.getIntWidth(BestType);
-  }
-  else if (NumNegativeBits) {
-    // If there is a negative value, figure out the smallest integer type (of
-    // int/long/longlong) that fits.
-    // If it's packed, check also if it fits a char or a short.
-    if (Packed && NumNegativeBits <= CharWidth && NumPositiveBits < CharWidth) {
-      BestType = Context.SignedCharTy;
-      BestWidth = CharWidth;
-    } else if (Packed && NumNegativeBits <= ShortWidth &&
-               NumPositiveBits < ShortWidth) {
-      BestType = Context.ShortTy;
-      BestWidth = ShortWidth;
-    } else if (NumNegativeBits <= IntWidth && NumPositiveBits < IntWidth) {
-      BestType = Context.IntTy;
-      BestWidth = IntWidth;
-    } else {
-      BestWidth = Context.getTargetInfo().getLongWidth();
-
-      if (NumNegativeBits <= BestWidth && NumPositiveBits < BestWidth) {
-        BestType = Context.LongTy;
-      } else {
-        BestWidth = Context.getTargetInfo().getLongLongWidth();
-
-        if (NumNegativeBits > BestWidth || NumPositiveBits >= BestWidth)
-          Diag(Enum->getLocation(), diag::ext_enum_too_large);
-        BestType = Context.LongLongTy;
-      }
-    }
-    BestPromotionType = (BestWidth <= IntWidth ? Context.IntTy : BestType);
   } else {
-    // If there is no negative value, figure out the smallest type that fits
-    // all of the enumerator values.
-    // If it's packed, check also if it fits a char or a short.
-    if (Packed && NumPositiveBits <= CharWidth) {
-      BestType = Context.UnsignedCharTy;
-      BestPromotionType = Context.IntTy;
-      BestWidth = CharWidth;
-    } else if (Packed && NumPositiveBits <= ShortWidth) {
-      BestType = Context.UnsignedShortTy;
-      BestPromotionType = Context.IntTy;
-      BestWidth = ShortWidth;
-    } else if (NumPositiveBits <= IntWidth) {
-      BestType = Context.UnsignedIntTy;
-      BestWidth = IntWidth;
-      BestPromotionType
-        = (NumPositiveBits == BestWidth || !getLangOpts().CPlusPlus)
-                           ? Context.UnsignedIntTy : Context.IntTy;
-    } else if (NumPositiveBits <=
-               (BestWidth = Context.getTargetInfo().getLongWidth())) {
-      BestType = Context.UnsignedLongTy;
-      BestPromotionType
-        = (NumPositiveBits == BestWidth || !getLangOpts().CPlusPlus)
-                           ? Context.UnsignedLongTy : Context.LongTy;
-    } else {
-      BestWidth = Context.getTargetInfo().getLongLongWidth();
-      if (NumPositiveBits > BestWidth) {
-        // This can happen with bit-precise integer types, but those are not
-        // allowed as the type for an enumerator per C23 6.7.2.2p4 and p12.
-        // FIXME: GCC uses __int128_t and __uint128_t for cases that fit within
-        // a 128-bit integer, we should consider doing the same.
-        Diag(Enum->getLocation(), diag::ext_enum_too_large);
-      }
-      BestType = Context.UnsignedLongLongTy;
-      BestPromotionType
-        = (NumPositiveBits == BestWidth || !getLangOpts().CPlusPlus)
-                           ? Context.UnsignedLongLongTy : Context.LongLongTy;
-    }
+    bool EnumTooLarge = Context.computeBestEnumTypes(
+        Packed, NumNegativeBits, NumPositiveBits, BestType, BestPromotionType);
+    BestWidth = Context.getIntWidth(BestType);
+    if (EnumTooLarge)
+      Diag(Enum->getLocation(), diag::ext_enum_too_large);
   }
 
   // Loop over all of the enumerator constants, changing their types to match
@@ -20197,7 +20132,7 @@ void Sema::ActOnEnumBody(SourceLocation EnumLoc, SourceRange BraceRange,
       //  int; or,
       //  - the enumerated type
       NewTy = Context.IntTy;
-      NewWidth = IntWidth;
+      NewWidth = Context.getTargetInfo().getIntWidth();
       NewSign = true;
     } else if (ECD->getType() == BestType) {
       // Already the right type!