Change in I/O Streams

Hi all,

There is going to be a sweeping change in how the I/O streams are used. We'll no longer be using std::cout, std::cerr, std::cin, etc. in each file. Instead, new LLVM streams will be used. The reason for this is because each "#include <iostream>" introduces an overhead in each compilation unit due to it needing to make sure that all of the std::c* streams are constructed first. This is a terrible waste of resources and one which we can do without.

The changes should be pretty transparent. There may be a few places which need a hack to support sstreams. This will be solved in the future.

Here's what the changes are:

Old Way New Way
------- -------
#include <iostream> #include "llvm/Support/Streams.h"
        class llvm_ostream; // forward declaration

std::cout llvm_cout
std::cerr llvm_cerr
std::cin llvm_cin

DEBUG(std::cerr << "foo"); DOUT << "foo";

The changes are going to be gradual. I'll be checking them in over the next week. I'll send out more information about changes in the future.