Fix clang folly::to failure

Summary:
Converting an enum class to a string fails with clang.
Adfinder clang build failure is http://ci-fbcode.fb.com:8080/builders/project/builds/146520/steps/build/logs/stdio
Our version of clang supports std::underlying_type so use that implementation instead.

Test Plan:
fbconfig -r folly && fbmake runtests (only failure is folly/experimental/symbolizer/test:symbolizer_test which failed before this diff)
fbconfig --clang folly/test:conv_test && fbmake runtests (fbconfig -r --clang folly fails and fbconfig --clang folly/test && fbmake has some unrelated compile errors)
Build adfinder with clang

Reviewed By: delong.j@fb.com

FB internal diff: D1178770

diff --git a/folly/Conv.h b/folly/Conv.h
index 12936cc3506aa2e7bc844e244e07c90349bd4078..8eb7e52cef789fdeef1fa3dc0476a3232be8381d 100644 (file)
--- a/folly/Conv.h
+++ b/folly/Conv.h
@@ -379,7 +379,7 @@ toAppend(Src value, Tgt * result) {
   toAppend<Tgt>(static_cast<Intermediate>(value), result);
 }
 
-#if defined(__GNUC__) && __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7)
+#if defined(__clang__) || __GNUC_PREREQ(4, 7)
 // std::underlying_type became available by gcc 4.7.0
 
 /**
@@ -1071,7 +1071,7 @@ to(const Src & value) {
  * Enum to anything and back
  ******************************************************************************/
 
-#if defined(__GNUC__) && __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7)
+#if defined(__clang__) || __GNUC_PREREQ(4, 7)
 // std::underlying_type became available by gcc 4.7.0
 
 template <class Tgt, class Src>

diff --git a/folly/test/ConvTest.cpp b/folly/test/ConvTest.cpp
index 49da954d8bfc9cecb661292c05cb1b7f8b17a035..3cd09149ff53ce42b44c43c86ad3224f96377dac 100644 (file)
--- a/folly/test/ConvTest.cpp
+++ b/folly/test/ConvTest.cpp
@@ -592,7 +592,7 @@ TEST(Conv, UnsignedEnum) {
   }
 }
 
-#if defined(__GNUC__) && __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7)
+#if defined(__clang__) || __GNUC_PREREQ(4, 7)
 // to<enum class> and to(enum class) only supported in gcc 4.7 onwards
 
 TEST(Conv, UnsignedEnumClass) {