1 files changed, 38 insertions, 4 deletions

diff --git a/include/llvm/MC/MCSymbol.h b/include/llvm/MC/MCSymbol.h
index 06f50ae..235e661 100644
--- a/include/llvm/MC/MCSymbol.h
+++ b/include/llvm/MC/MCSymbol.h
@@ -6,6 +6,10 @@
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
+//
+// This file contains the declaration of the MCSymbol class.
+//
+//===----------------------------------------------------------------------===//
 
 #ifndef LLVM_MC_MCSYMBOL_H
 #define LLVM_MC_MCSYMBOL_H
@@ -13,18 +17,48 @@
 #include <string>
 
 namespace llvm {
+  class MCSection;
+  class MCContext;
+
+  /// MCSymbol - Instances of this class represent a symbol name in the MC file,
+  /// and MCSymbols are created and unique'd by the MCContext class.
+  ///
+  /// If the symbol is defined/emitted into the current translation unit, the
+  /// Section member is set to indicate what section it lives in.  Otherwise, if
+  /// it is a reference to an external entity, it has a null section.  
+  /// 
   class MCSymbol {
-    MCSection *Section;
+    /// Name - The name of the symbol.
     std::string Name;
+    /// Section - The section the symbol is defined in, or null if the symbol
+    /// has not been defined in the associated translation unit.
+    MCSection *Section;
+    
+    /// IsTemporary - True if this is an assembler temporary label, which
+    /// typically does not survive in the .o file's symbol table.  Usually
+    /// "Lfoo" or ".foo".
     unsigned IsTemporary : 1;
+    
+    /// IsExternal - True if this symbol has been implicitly defined as an
+    /// external, for example by using it in an expression without ever emitting
+    /// it as a label. The @var Section for an external symbol is always null.
+    unsigned IsExternal : 1;
 
-  public:
+  private:  // MCContext creates and uniques these.
+    friend class MCContext;
     MCSymbol(const char *_Name, bool _IsTemporary) 
-      : Section(0), Name(_Name), IsTemporary(_IsTemporary) {}
-
+      : Name(_Name), Section(0), IsTemporary(_IsTemporary), IsExternal(false) {}
+    
+    MCSymbol(const MCSymbol&);       // DO NOT IMPLEMENT
+    void operator=(const MCSymbol&); // DO NOT IMPLEMENT
+  public:
+    
     MCSection *getSection() const { return Section; }
     void setSection(MCSection *Value) { Section = Value; }
 
+    bool isExternal() const { return IsExternal; }
+    void setExternal(bool Value) { IsExternal = Value; }
+
     const std::string &getName() const { return Name; }
   };