[AST][NFC] Pack CXXThrowExpr

Use the newly available space in the bit-fields of Stmt.
This saves 8 bytes per CXXThrowExpr.

llvm-svn: 347136

3 files changed, 38 insertions, 23 deletions

diff --git a/clang/include/clang/AST/ExprCXX.h b/clang/include/clang/AST/ExprCXX.h
index 94fba581c1b..847a9fe2a17 100644
--- a/clang/include/clang/AST/ExprCXX.h
+++ b/clang/include/clang/AST/ExprCXX.h
@@ -1003,42 +1003,43 @@ public:
 class CXXThrowExpr : public Expr {
   friend class ASTStmtReader;
 
-  Stmt *Op;
-  SourceLocation ThrowLoc;
-
-  /// Whether the thrown variable (if any) is in scope.
-  unsigned IsThrownVariableInScope : 1;
+  /// The optional expression in the throw statement.
+  Stmt *Operand;
 
 public:
   // \p Ty is the void type which is used as the result type of the
-  // expression.  The \p l is the location of the throw keyword.  \p expr
-  // can by null, if the optional expression to throw isn't present.
-  CXXThrowExpr(Expr *expr, QualType Ty, SourceLocation l,
+  // expression. The \p Loc is the location of the throw keyword.
+  // \p Operand is the expression in the throw statement, and can be
+  // null if not present.
+  CXXThrowExpr(Expr *Operand, QualType Ty, SourceLocation Loc,
                bool IsThrownVariableInScope)
       : Expr(CXXThrowExprClass, Ty, VK_RValue, OK_Ordinary, false, false,
-             expr && expr->isInstantiationDependent(),
-             expr && expr->containsUnexpandedParameterPack()),
-        Op(expr), ThrowLoc(l),
-        IsThrownVariableInScope(IsThrownVariableInScope) {}
+             Operand && Operand->isInstantiationDependent(),
+             Operand && Operand->containsUnexpandedParameterPack()),
+        Operand(Operand) {
+    CXXThrowExprBits.ThrowLoc = Loc;
+    CXXThrowExprBits.IsThrownVariableInScope = IsThrownVariableInScope;
+  }
   CXXThrowExpr(EmptyShell Empty) : Expr(CXXThrowExprClass, Empty) {}
 
-  const Expr *getSubExpr() const { return cast_or_null<Expr>(Op); }
-  Expr *getSubExpr() { return cast_or_null<Expr>(Op); }
+  const Expr *getSubExpr() const { return cast_or_null<Expr>(Operand); }
+  Expr *getSubExpr() { return cast_or_null<Expr>(Operand); }
 
-  SourceLocation getThrowLoc() const { return ThrowLoc; }
+  SourceLocation getThrowLoc() const { return CXXThrowExprBits.ThrowLoc; }
 
   /// Determines whether the variable thrown by this expression (if any!)
   /// is within the innermost try block.
   ///
   /// This information is required to determine whether the NRVO can apply to
   /// this variable.
-  bool isThrownVariableInScope() const { return IsThrownVariableInScope; }
-
-  SourceLocation getBeginLoc() const LLVM_READONLY { return ThrowLoc; }
+  bool isThrownVariableInScope() const {
+    return CXXThrowExprBits.IsThrownVariableInScope;
+  }
 
+  SourceLocation getBeginLoc() const { return getThrowLoc(); }
   SourceLocation getEndLoc() const LLVM_READONLY {
     if (!getSubExpr())
-      return ThrowLoc;
+      return getThrowLoc();
     return getSubExpr()->getEndLoc();
   }
 
@@ -1048,7 +1049,7 @@ public:
 
   // Iterators
   child_range children() {
-    return child_range(&Op, Op ? &Op+1 : &Op);
+    return child_range(&Operand, Operand ? &Operand + 1 : &Operand);
   }
 };
 
diff --git a/clang/include/clang/AST/Stmt.h b/clang/include/clang/AST/Stmt.h
index b3394a81f47..34667d1df56 100644
--- a/clang/include/clang/AST/Stmt.h
+++ b/clang/include/clang/AST/Stmt.h
@@ -535,6 +535,19 @@ protected:
     SourceLocation Loc;
   };
 
+  class CXXThrowExprBitfields {
+    friend class ASTStmtReader;
+    friend class CXXThrowExpr;
+
+    unsigned : NumExprBits;
+
+    /// Whether the thrown variable (if any) is in scope.
+    unsigned IsThrownVariableInScope : 1;
+
+    /// The location of the "throw".
+    SourceLocation ThrowLoc;
+  };
+
   class TypeTraitExprBitfields {
     friend class ASTStmtReader;
     friend class ASTStmtWriter;
@@ -636,6 +649,7 @@ protected:
     CXXBoolLiteralExprBitfields CXXBoolLiteralExprBits;
     CXXNullPtrLiteralExprBitfields CXXNullPtrLiteralExprBits;
     CXXThisExprBitfields CXXThisExprBits;
+    CXXThrowExprBitfields CXXThrowExprBits;
     TypeTraitExprBitfields TypeTraitExprBits;
     ExprWithCleanupsBitfields ExprWithCleanupsBits;
 
diff --git a/clang/lib/Serialization/ASTReaderStmt.cpp b/clang/lib/Serialization/ASTReaderStmt.cpp
index 15e89db2092..184ae372231 100644
--- a/clang/lib/Serialization/ASTReaderStmt.cpp
+++ b/clang/lib/Serialization/ASTReaderStmt.cpp
@@ -1473,9 +1473,9 @@ void ASTStmtReader::VisitCXXThisExpr(CXXThisExpr *E) {
 
 void ASTStmtReader::VisitCXXThrowExpr(CXXThrowExpr *E) {
   VisitExpr(E);
-  E->ThrowLoc = ReadSourceLocation();
-  E->Op = Record.readSubExpr();
-  E->IsThrownVariableInScope = Record.readInt();
+  E->CXXThrowExprBits.ThrowLoc = ReadSourceLocation();
+  E->Operand = Record.readSubExpr();
+  E->CXXThrowExprBits.IsThrownVariableInScope = Record.readInt();
 }
 
 void ASTStmtReader::VisitCXXDefaultArgExpr(CXXDefaultArgExpr *E) {