Update Subzero to start parsing PNaCl bitcode files.

This patch only handles global addresses in PNaCl bitcode files.
Function blocks are still not parsed. Also, factors out a common API
for translation, so that generated ICE can always be translated using
the same code.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3892
R=jvoung@chromium.org, stichnot@chromium.org

Review URL: https://codereview.chromium.org/361733002
diff --git a/src/IceTranslator.cpp b/src/IceTranslator.cpp
new file mode 100644
index 0000000..7eb0fc0
--- /dev/null
+++ b/src/IceTranslator.cpp
@@ -0,0 +1,58 @@
+//===- subzero/src/IceTranslator.cpp - ICE to machine code ------*- C++ -*-===//
+//
+//                        The Subzero Code Generator
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the general driver class for translating ICE to
+// machine code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "IceTranslator.h"
+
+#include "IceCfg.h"
+#include "IceClFlags.h"
+#include "IceTargetLowering.h"
+
+#include <iostream>
+
+using namespace Ice;
+
+Translator::~Translator() {}
+
+void Translator::translateFcn(Ice::Cfg *Fcn) {
+  Func.reset(Fcn);
+  if (Flags.DisableInternal)
+    Func->setInternal(false);
+  if (Flags.DisableTranslation) {
+    Func->dump();
+  } else {
+    Ice::Timer TTranslate;
+    Func->translate();
+    if (Flags.SubzeroTimingEnabled) {
+      std::cerr << "[Subzero timing] Translate function "
+                << Func->getFunctionName() << ": " << TTranslate.getElapsedSec()
+                << " sec\n";
+    }
+    if (Func->hasError()) {
+      std::cerr << "ICE translation error: " << Func->getError() << "\n";
+      ExitStatus = 1;
+    }
+
+    Ice::Timer TEmit;
+    Func->emit();
+    if (Flags.SubzeroTimingEnabled) {
+      std::cerr << "[Subzero timing] Emit function " << Func->getFunctionName()
+                << ": " << TEmit.getElapsedSec() << " sec\n";
+    }
+  }
+}
+
+void Translator::emitConstants() {
+  if (!Flags.DisableTranslation && Func)
+    Func->getTarget()->emitConstants();
+}