Refactor optimization pass handling.

Refactor the optimization passes to explicitly use the passes. This commit
just re-implements the same passes as were already being run.

It also adds an option (behind `-Z`) to run the LLVM lint pass on the
unoptimized IR.

src/rustllvm/rustllvm.h

@@ -0,0 +1,57 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#include "llvm/IR/InlineAsm.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/Linker.h"
+#include "llvm/PassManager.h"
+#include "llvm/IR/InlineAsm.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/Analysis/Verifier.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/Analysis/Lint.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/Assembly/Parser.h"
+#include "llvm/Assembly/PrintModulePass.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/DynamicLibrary.h"
+#include "llvm/Support/Memory.h"
+#include "llvm/ExecutionEngine/ExecutionEngine.h"
+#include "llvm/ExecutionEngine/JIT.h"
+#include "llvm/ExecutionEngine/JITMemoryManager.h"
+#include "llvm/ExecutionEngine/MCJIT.h"
+#include "llvm/ExecutionEngine/Interpreter.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/Instrumentation.h"
+#include "llvm/Transforms/Vectorize.h"
+#include "llvm-c/Core.h"
+#include "llvm-c/BitReader.h"
+#include "llvm-c/Object.h"
+
+// Used by RustMCJITMemoryManager::getPointerToNamedFunction()
+// to get around glibc issues. See the function for more information.
+#ifdef __linux__
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#endif
+