Remove unused function.

Author: adrian-prantl

lib/IRGen/IRGenDebugInfo.cpp

@@ -739,9 +739,6 @@ llvm::DISubprogram *IRGenDebugInfo::emitFunction(
   return SP;
 }
 
-/// TODO: This is no longer needed.
-void IRGenDebugInfo::eraseFunction(llvm::Function *Fn) {}
-
 void IRGenDebugInfo::emitImport(ImportDecl *D) {
   if (Opts.DebugInfoKind == IRGenDebugInfoKind::LineTables)
     return;

lib/IRGen/IRGenDebugInfo.h

@@ -197,9 +197,6 @@ class IRGenDebugInfo {
   /// Return the DIBuilder.
   llvm::DIBuilder &getBuilder() { return DBuilder; }
 
-  /// Removes the function from the Functions map again.
-  void eraseFunction(llvm::Function *Fn);
-
 private:
   StringRef BumpAllocatedString(const char *Data, size_t Length);
   StringRef BumpAllocatedString(std::string S);