Create a MCSymbolELF.

This create a MCSymbolELF class and moves SymbolSize since only ELF
needs a size expression.

This reduces the size of MCSymbol from 56 to 48 bytes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238801 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCSymbolELF.h

@@ -0,0 +1,31 @@
+//===- MCSymbolELF.h -  -----------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_MC_MCSYMBOLELF_H
+#define LLVM_MC_MCSYMBOLELF_H
+
+#include "llvm/MC/MCSymbol.h"
+
+namespace llvm {
+class MCSymbolELF : public MCSymbol {
+  /// An expression describing how to calculate the size of a symbol. If a
+  /// symbol has no size this field will be NULL.
+  const MCExpr *SymbolSize = nullptr;
+
+public:
+  MCSymbolELF(const StringMapEntry<bool> *Name, bool isTemporary)
+      : MCSymbol(true, Name, isTemporary) {}
+  void setSize(const MCExpr *SS) { SymbolSize = SS; }
+
+  const MCExpr *getSize() const { return SymbolSize; }
+
+  static bool classof(const MCSymbol *S) { return S->isELF(); }
+};
+}
+
+#endif