Add passes for applying SFI sandboxing at the LLVM IR level

lib/Transforms/NaCl/StripTls.cpp

+//===- StripTls.cpp - Remove the thread_local attribute from variables-----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// XXX
+//
+//===----------------------------------------------------------------------===//
+
+// #include "llvm/IR/Function.h"
+// #include "llvm/IR/Instructions.h"
+// #include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+// #include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/NaCl.h"
+
+using namespace llvm;
+
+namespace {
+  // This is a ModulePass so that XXX...
+  class StripTls : public ModulePass {
+  public:
+    static char ID; // Pass identification, replacement for typeid
+    StripTls() : ModulePass(ID) {
+      initializeStripTlsPass(*PassRegistry::getPassRegistry());
+    }
+
+    virtual bool runOnModule(Module &M);
+  };
+}
+
+char StripTls::ID = 0;
+INITIALIZE_PASS(StripTls, "strip-tls",
+                "Remove the thread_local attribute from variables",
+                false, false)
+
+bool StripTls::runOnModule(Module &M) {
+  bool Changed = false;
+  for (Module::global_iterator GV = M.global_begin(), E = M.global_end();
+       GV != E;
+       ++GV) {
+    if (GV->isThreadLocal()) {
+      GV->setThreadLocal(false);
+      Changed = true;
+    }
+  }
+  return Changed;
+}
+
+ModulePass *llvm::createStripTlsPass() {
+  return new StripTls();
+}