Use std::error_code instead of llvm::error_code.

The idea of this patch is to turn llvm/Support/system_error.h into a
transitional header that just brings in the erorr_code api to the llvm
namespace. I will remove it shortly afterwards.

The cases where the general idea needed some tweaking:

* std::errc is a namespace in msvc, so we cannot use "using std::errc". I could
add an #ifdef, but there were not that many uses, so I just added std:: to
them in this patch.

* Template specialization had to be moved to the std namespace in this
patch set already.

* The msvc implementation of default_error_condition doesn't seem to
provide the same transformations as we need. Not too surprising since
the standard doesn't actually say what "equivalent" means. I fixed the
problem by keeping our old mapping and using it at error_code
construction time.

Despite these shortcomings I think this is still a good thing. Some reasons:

* The different implementations of system_error might improve over time.
* It removes 925 lines of code from llvm already.
* It removes 6313 bytes from the text segment of the clang binary when
it is built with gcc and 2816 bytes when building with clang and
libstdc++.

llvm-svn: 210687

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Support/MemoryBuffer.cpp b/llvm/lib/Support/MemoryBuffer.cpp
index b729809..1f69326 100644
--- a/llvm/lib/Support/MemoryBuffer.cpp
+++ b/llvm/lib/Support/MemoryBuffer.cpp
@@ -361,7 +361,7 @@ static error_code getOpenFileImpl(int FD, const char *Filename,
   if (!Buf) {
     // Failed to create a buffer. The only way it can fail is if
     // new(std::nothrow) returns 0.
-    return make_error_code(errc::not_enough_memory);
+    return make_error_code(std::errc::not_enough_memory);
   }
 
   std::unique_ptr<MemoryBuffer> SB(Buf);