[Clang] NFC: Move Arm type attributes to separate trailing object.

clang/include/clang/AST/Type.h

@@ -4029,6 +4029,22 @@ class FunctionType : public Type {
   /// because TrailingObjects cannot handle repeated types.
   struct ExceptionType { QualType Type; };
 
+  /// A simple holder for various uncommon bits which do not fit in
+  /// FunctionTypeBitfields. Aligned to alignof(void *) to maintain the
+  /// alignment of subsequent objects in TrailingObjects.
+  struct alignas(void *) FunctionTypeExtraBitfields {
+    /// The number of types in the exception specification.
+    /// A whole unsigned is not needed here and according to
+    /// [implimits] 8 bits would be enough here.
+    unsigned NumExceptionType : 10;
+
+    LLVM_PREFERRED_TYPE(bool)
+    unsigned HasArmTypeAttributes : 1;
+
+    FunctionTypeExtraBitfields()
+        : NumExceptionType(0), HasArmTypeAttributes(false) {}
+  };
+
   /// The AArch64 SME ACLE (Arm C/C++ Language Extensions) define a number
   /// of function type attributes that can be set on function types, including
   /// function pointers.
@@ -4042,7 +4058,8 @@ class FunctionType : public Type {
     SME_ZAMask = 0b111 << SME_ZAShift,
 
     SME_AttributeMask = 0b111'111 // We only support maximum 6 bits because of
-                                  // the bitmask in FunctionTypeExtraBitfields.
+                                  // the bitmask in FunctionTypeArmAttributes
+                                  // and ExtProtoInfo.
   };
 
   enum ArmStateValue : unsigned {
@@ -4057,20 +4074,15 @@ class FunctionType : public Type {
     return (ArmStateValue)((AttrBits & SME_ZAMask) >> SME_ZAShift);
   }
 
-  /// A simple holder for various uncommon bits which do not fit in
-  /// FunctionTypeBitfields. Aligned to alignof(void *) to maintain the
-  /// alignment of subsequent objects in TrailingObjects.
-  struct alignas(void *) FunctionTypeExtraBitfields {
-    /// The number of types in the exception specification.
-    /// A whole unsigned is not needed here and according to
-    /// [implimits] 8 bits would be enough here.
-    unsigned NumExceptionType : 10;
-
+  /// A holder for Arm type attributes as described in the Arm C/C++
+  /// Language extensions which are not particularly common to all
+  /// types and therefore accounted separately from FunctionTypeBitfields.
+  struct alignas(void *) FunctionTypeArmAttributes {
     /// Any AArch64 SME ACLE type attributes that need to be propagated
     /// on declarations and function pointers.
     unsigned AArch64SMEAttributes : 6;
-    FunctionTypeExtraBitfields()
-        : NumExceptionType(0), AArch64SMEAttributes(SME_NormalFunction) {}
+
+    FunctionTypeArmAttributes() : AArch64SMEAttributes(SME_NormalFunction) {}
   };
 
 protected:
@@ -4169,7 +4181,8 @@ class FunctionProtoType final
       public llvm::FoldingSetNode,
       private llvm::TrailingObjects<
           FunctionProtoType, QualType, SourceLocation,
-          FunctionType::FunctionTypeExtraBitfields, FunctionType::ExceptionType,
+          FunctionType::FunctionTypeExtraBitfields,
+          FunctionType::FunctionTypeArmAttributes, FunctionType::ExceptionType,
           Expr *, FunctionDecl *, FunctionType::ExtParameterInfo, Qualifiers> {
   friend class ASTContext; // ASTContext creates these.
   friend TrailingObjects;
@@ -4276,7 +4289,11 @@ class FunctionProtoType final
 
     bool requiresFunctionProtoTypeExtraBitfields() const {
       return ExceptionSpec.Type == EST_Dynamic ||
-             AArch64SMEAttributes != SME_NormalFunction;
+             requiresFunctionProtoTypeArmAttributes();
+    }
+
+    bool requiresFunctionProtoTypeArmAttributes() const {
+      return AArch64SMEAttributes != SME_NormalFunction;
     }
 
     void setArmSMEAttribute(AArch64SMETypeAttributes Kind, bool Enable = true) {
@@ -4296,6 +4313,10 @@ class FunctionProtoType final
     return isVariadic();
   }
 
+  unsigned numTrailingObjects(OverloadToken<FunctionTypeArmAttributes>) const {
+    return hasArmTypeAttributes();
+  }
+
   unsigned numTrailingObjects(OverloadToken<FunctionTypeExtraBitfields>) const {
     return hasExtraBitfields();
   }
@@ -4384,6 +4405,12 @@ class FunctionProtoType final
 
   }
 
+  bool hasArmTypeAttributes() const {
+    return FunctionTypeBits.HasExtraBitfields &&
+           getTrailingObjects<FunctionTypeExtraBitfields>()
+               ->HasArmTypeAttributes;
+  }
+
   bool hasExtQualifiers() const {
     return FunctionTypeBits.HasExtQuals;
   }
@@ -4595,9 +4622,9 @@ class FunctionProtoType final
   /// Return a bitmask describing the SME attributes on the function type, see
   /// AArch64SMETypeAttributes for their values.
   unsigned getAArch64SMEAttributes() const {
-    if (!hasExtraBitfields())
+    if (!hasArmTypeAttributes())
       return SME_NormalFunction;
-    return getTrailingObjects<FunctionTypeExtraBitfields>()
+    return getTrailingObjects<FunctionTypeArmAttributes>()
         ->AArch64SMEAttributes;
   }
 

clang/lib/AST/ASTContext.cpp

@@ -4484,10 +4484,11 @@ QualType ASTContext::getFunctionTypeInternal(
       EPI.ExceptionSpec.Type, EPI.ExceptionSpec.Exceptions.size());
   size_t Size = FunctionProtoType::totalSizeToAlloc<
       QualType, SourceLocation, FunctionType::FunctionTypeExtraBitfields,
-      FunctionType::ExceptionType, Expr *, FunctionDecl *,
-      FunctionProtoType::ExtParameterInfo, Qualifiers>(
+      FunctionType::FunctionTypeArmAttributes, FunctionType::ExceptionType,
+      Expr *, FunctionDecl *, FunctionProtoType::ExtParameterInfo, Qualifiers>(
       NumArgs, EPI.Variadic, EPI.requiresFunctionProtoTypeExtraBitfields(),
-      ESH.NumExceptionType, ESH.NumExprPtr, ESH.NumFunctionDeclPtr,
+      EPI.requiresFunctionProtoTypeArmAttributes(), ESH.NumExceptionType,
+      ESH.NumExprPtr, ESH.NumFunctionDeclPtr,
       EPI.ExtParameterInfos ? NumArgs : 0,
       EPI.TypeQuals.hasNonFastQualifiers() ? 1 : 0);
 

clang/lib/AST/Type.cpp

@@ -3459,6 +3459,14 @@ FunctionProtoType::FunctionProtoType(QualType result, ArrayRef<QualType> params,
     FunctionTypeBits.HasExtraBitfields = false;
   }
 
+  if (epi.requiresFunctionProtoTypeArmAttributes()) {
+    auto &ArmTypeAttrs = *getTrailingObjects<FunctionTypeArmAttributes>();
+    ArmTypeAttrs = FunctionTypeArmAttributes();
+
+    // Also set the bit in FunctionTypeExtraBitfields
+    auto &ExtraBits = *getTrailingObjects<FunctionTypeExtraBitfields>();
+    ExtraBits.HasArmTypeAttributes = true;
+  }
 
   // Fill in the trailing argument array.
   auto *argSlot = getTrailingObjects<QualType>();
@@ -3470,10 +3478,10 @@ FunctionProtoType::FunctionProtoType(QualType result, ArrayRef<QualType> params,
 
   // Propagate the SME ACLE attributes.
   if (epi.AArch64SMEAttributes != SME_NormalFunction) {
-    auto &ExtraBits = *getTrailingObjects<FunctionTypeExtraBitfields>();
+    auto &ArmTypeAttrs = *getTrailingObjects<FunctionTypeArmAttributes>();
     assert(epi.AArch64SMEAttributes <= SME_AttributeMask &&
            "Not enough bits to encode SME attributes");
-    ExtraBits.AArch64SMEAttributes = epi.AArch64SMEAttributes;
+    ArmTypeAttrs.AArch64SMEAttributes = epi.AArch64SMEAttributes;
   }
 
   // Fill in the exception type array if present.