Initial support for dumping DWARF corresponding to Swift code

src/common/language.h

Index: src/common/language.h
diff --git a/src/common/language.h b/src/common/language.h
index bbe303347a32a160f6da2aeb69284e6563620e2f..9e92d8139f7471e33e27857da9c45237879e3d3b 100644
--- a/src/common/language.h
+++ b/src/common/language.h
@@ -77,9 +77,24 @@ class Language {
   virtual string MakeQualifiedName (const string &parent_name,
                                     const string &name) const = 0;
 
+  // Special return value from DemangleName() to indicate that demangling was
+  // not performed because it’s not appropriate to attempt.
+  static const int kDontDemangle;
+
+  // Wraps abi::__cxa_demangle() or similar for languages where appropriate.
+  // Returns the demangler's status value, or kDontDemangle if demangling (and
+  // error reporting) is inappropriate. Returns 0 on success, with |demangled|
+  // set.
+  virtual int DemangleName(const string& mangled, std::string* demangled)

[Ted Mielczarek, 2016/09/14 10:20:10]

I think it would be better to make this return an enum with three possible
values:
* Success
* Failure
* DontDemangle

The `__cxa_demangle` status codes aren't likely to be of any use to the caller
anyway.

+      const {
+    demangled->clear();
+    return kDontDemangle;
+  }
+
   // Instances for specific languages.
   static const Language * const CPlusPlus,
                         * const Java,
+                        * const Swift,
                         * const Assembler;
 };