Defining a new API for debug options that doesn't rely on static global cl::opts.

Summary:
This is based on the discussions from the LLVMDev thread:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-August/075886.html

Reviewers: chandlerc

Reviewed By: chandlerc

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5389

llvm-svn: 219854
diff --git a/llvm/lib/Support/CMakeLists.txt b/llvm/lib/Support/CMakeLists.txt
index 8ba992a..daed4f1 100644
--- a/llvm/lib/Support/CMakeLists.txt
+++ b/llvm/lib/Support/CMakeLists.txt
@@ -40,6 +40,7 @@
   MemoryBuffer.cpp
   MemoryObject.cpp
   MD5.cpp
+  Options.cpp
   PluginLoader.cpp
   PrettyStackTrace.cpp
   RandomNumberGenerator.cpp
diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
index 2c5174dc..9d5f1580 100644
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -113,9 +113,15 @@
 }
 
 void Option::removeArgument() {
-  assert(NextRegistered && "argument never registered");
-  assert(RegisteredOptionList == this && "argument is not the last registered");
-  RegisteredOptionList = NextRegistered;
+  if (RegisteredOptionList == this) {
+    RegisteredOptionList = NextRegistered;
+    MarkOptionsChanged();
+    return;
+  }
+  Option *O = RegisteredOptionList;
+  for (; O->NextRegistered != this; O = O->NextRegistered)
+    ;
+  O->NextRegistered = NextRegistered;
   MarkOptionsChanged();
 }
 
diff --git a/llvm/lib/Support/Options.cpp b/llvm/lib/Support/Options.cpp
new file mode 100644
index 0000000..7125845
--- /dev/null
+++ b/llvm/lib/Support/Options.cpp
@@ -0,0 +1,33 @@
+//===- llvm/Support/Options.cpp - Debug options support ---------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the helper objects for defining debug options using the
+// new API built on cl::opt, but not requiring the use of static globals.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Options.h"
+#include "llvm/Support/ManagedStatic.h"
+
+using namespace llvm;
+
+OptionRegistry::~OptionRegistry() {
+  for (auto IT = Options.begin(); IT != Options.end(); ++IT)
+    delete IT->second;
+}
+
+void OptionRegistry::addOption(void *Key, cl::Option *O) {
+  assert(Options.find(Key) == Options.end() &&
+         "Argument with this key already registerd");
+  Options.insert(std::make_pair(Key, O));
+}
+
+static ManagedStatic<OptionRegistry> OR;
+
+OptionRegistry &OptionRegistry::instance() { return *OR; }