raw_ostream: add operator<< overload for std::error_code

Summary:
The main motivation for this is unit tests, which contain a large macro
for pretty-printing std::error_code, and this macro is duplicated in
every file that needs to do this. However, the functionality may be
useful elsewhere too.

In this patch I have reimplemented the existing ASSERT_NO_ERROR macros
to reuse the new functionality, but I have kept the macro (as a
one-liner) as it is slightly more readable than ASSERT_EQ(...,
std::error_code()).

Reviewers: sammccall, ilya-biryukov

Subscribers: zturner, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65643

llvm-svn: 368849

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
index b9989371f5e..4a2d6d20951 100644
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -139,6 +139,11 @@ raw_ostream &raw_ostream::operator<<(long long N) {
   return *this;
 }
 
+raw_ostream &raw_ostream::operator<<(std::error_code EC) {
+  return *this << EC.message() << " (" << EC.category().name() << ':'
+               << EC.value() << ')';
+}
+
 raw_ostream &raw_ostream::write_hex(unsigned long long N) {
   llvm::write_hex(*this, N, HexPrintStyle::Lower);
   return *this;