Clang support for constexpr StringPiece constructor

[folly.git] / folly / Portability.h

diff --git a/folly/Portability.h b/folly/Portability.h
index 23568db0486d16cdfdaad8120383f6cf9443822f..594ab9aa6a73a267cf14e4832b9e456ba951245a 100644 (file)
--- a/folly/Portability.h
+++ b/folly/Portability.h
@@ -17,6 +17,10 @@
 #ifndef FOLLY_PORTABILITY_H_
 #define FOLLY_PORTABILITY_H_
 
+#include <string.h>
+
+#include <cstddef>
+
 #ifndef FOLLY_NO_CONFIG
 #include <folly/folly-config.h>
 #endif
@@ -53,16 +57,18 @@
   #endif
 #endif
 
-// MaxAlign: max_align_t isn't supported by gcc
-#ifdef __GNUC__
-struct MaxAlign { char c; } __attribute__((__aligned__));
-#else /* !__GNUC__ */
-# error Cannot define MaxAlign on this platform
-#endif
-
 // compiler specific attribute translation
 // msvc should come first, so if clang is in msvc mode it gets the right defines
 
+#if defined(__clang__) || defined(__GNUC__)
+# define FOLLY_ALIGNED(size) __attribute__((__aligned__(size)))
+#elif defined(_MSC_VER)
+# define FOLLY_ALIGNED(size) __declspec(align(size))
+#else
+# error Cannot define FOLLY_ALIGNED on this platform
+#endif
+#define FOLLY_ALIGNED_MAX FOLLY_ALIGNED(alignof(std::max_align_t))
+
 // NOTE: this will only do checking in msvc with versions that support /analyze
 #if _MSC_VER
 # ifdef _USE_ATTRIBUTES_FOR_SAL
@@ -85,7 +91,7 @@ struct MaxAlign { char c; } __attribute__((__aligned__));
 #elif defined(_MSC_VER)
 # define FOLLY_DEPRECATED(msg) __declspec(deprecated(msg))
 #else
-# define FOLLY_DEPRECATED
+# define FOLLY_DEPRECATED(msg)
 #endif
 
 // noreturn
@@ -112,7 +118,7 @@ struct MaxAlign { char c; } __attribute__((__aligned__));
 #elif defined(__clang__) || defined(__GNUC__)
 # define FOLLY_ALWAYS_INLINE inline __attribute__((__always_inline__))
 #else
-# define FOLLY_ALWAYS_INLINE
+# define FOLLY_ALWAYS_INLINE inline
 #endif
 
 // detection for 64 bit
@@ -128,6 +134,12 @@ struct MaxAlign { char c; } __attribute__((__aligned__));
 # define FOLLY_A64 0
 #endif
 
+#if defined (__powerpc64__)
+# define FOLLY_PPC64 1
+#else
+# define FOLLY_PPC64 0
+#endif
+
 // packing is very ugly in msvc
 #ifdef _MSC_VER
 # define FOLLY_PACK_ATTR /**/
@@ -155,20 +167,11 @@ struct MaxAlign { char c; } __attribute__((__aligned__));
 # endif
 #endif
 
-
-/* Define macro wrappers for C++11's "final" and "override" keywords, which
- * are supported in gcc 4.7 but not gcc 4.6. */
-#if !defined(FOLLY_FINAL) && !defined(FOLLY_OVERRIDE)
-# if defined(__clang__) || __GNUC_PREREQ(4, 7)
-#  define FOLLY_FINAL final
-#  define FOLLY_OVERRIDE override
-# elif defined(_MSC_VER) && _MSC_VER >= 1600
-#  define FOLLY_FINAL final
-#  define FOLLY_OVERRIDE override
-# else
-#  define FOLLY_FINAL /**/
-#  define FOLLY_OVERRIDE /**/
-# endif
+#if defined(__GNUC__) && !defined(__APPLE__) && !__GNUC_PREREQ(4,9)
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56019
+// gcc 4.8.x incorrectly placed max_align_t in the root namespace
+// Alias it into std (where it's found in 4.9 and later)
+namespace std { typedef ::max_align_t max_align_t; }
 #endif
 
 /* Platform specific TLS support
@@ -207,6 +210,16 @@ struct MaxAlign { char c; } __attribute__((__aligned__));
 #define FOLLY_NAMESPACE_STD_END       }
 #endif
 
+// If the new c++ ABI is used, __cxx11 inline namespace needs to be added to
+// some types, e.g. std::list.
+#if _GLIBCXX_USE_CXX11_ABI
+# define FOLLY_GLIBCXX_NAMESPACE_CXX11_BEGIN _GLIBCXX_BEGIN_NAMESPACE_CXX11
+# define FOLLY_GLIBCXX_NAMESPACE_CXX11_END   _GLIBCXX_END_NAMESPACE_CXX11
+#else
+# define FOLLY_GLIBCXX_NAMESPACE_CXX11_BEGIN
+# define FOLLY_GLIBCXX_NAMESPACE_CXX11_END
+#endif
+
 // Some platforms lack clock_gettime(2) and clock_getres(2). Inject our own
 // versions of these into the global namespace.
 #if FOLLY_HAVE_CLOCK_GETTIME
@@ -269,28 +282,39 @@ typedef SSIZE_T ssize_t;
 
 #ifdef _M_IX86_FP
 # define FOLLY_SSE _M_IX86_FP
+# define FOLLY_SSE_MINOR 0
 #endif
 
 #endif
 
 #ifndef FOLLY_SSE
 # if defined(__SSE4_2__)
-#  define FOLLY_SSE 4.2
+#  define FOLLY_SSE 4
+#  define FOLLY_SSE_MINOR 2
 # elif defined(__SSE4_1__)
-#  define FOLLY_SSE 4.1
+#  define FOLLY_SSE 4
+#  define FOLLY_SSE_MINOR 1
 # elif defined(__SSE4__)
 #  define FOLLY_SSE 4
+#  define FOLLY_SSE_MINOR 0
 # elif defined(__SSE3__)
 #  define FOLLY_SSE 3
+#  define FOLLY_SSE_MINOR 0
 # elif defined(__SSE2__)
 #  define FOLLY_SSE 2
+#  define FOLLY_SSE_MINOR 0
 # elif defined(__SSE__)
 #  define FOLLY_SSE 1
+#  define FOLLY_SSE_MINOR 0
 # else
 #  define FOLLY_SSE 0
+#  define FOLLY_SSE_MINOR 0
 # endif
 #endif
 
+#define FOLLY_SSE_PREREQ(major, minor) \
+  (FOLLY_SSE > major || FOLLY_SSE == major && FOLLY_SSE_MINOR >= minor)
+
 #if FOLLY_UNUSUAL_GFLAGS_NAMESPACE
 namespace FOLLY_GFLAGS_NAMESPACE { }
 namespace gflags {
@@ -322,6 +346,14 @@ inline size_t malloc_usable_size(void* ptr) {
 
 namespace folly {
 
+inline void asm_volatile_memory() {
+#if defined(__clang__) || defined(__GNUC__)
+  asm volatile("" : : : "memory");
+#elif defined(_MSC_VER)
+  ::_ReadWriteBarrier();
+#endif
+}
+
 inline void asm_volatile_pause() {
 #if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
   ::_mm_pause();
@@ -329,6 +361,8 @@ inline void asm_volatile_pause() {
   asm volatile ("pause");
 #elif FOLLY_A64
   asm volatile ("wfe");
+#elif FOLLY_PPC64
+  asm volatile("or 27,27,27");
 #endif
 }
 inline void asm_pause() {
@@ -338,9 +372,18 @@ inline void asm_pause() {
   asm ("pause");
 #elif FOLLY_A64
   asm ("wfe");
+#elif FOLLY_PPC64
+  asm ("or 31,31,31");
 #endif
 }
 
+constexpr size_t constexpr_strlen(const char* s) {
+#if defined(__clang__)
+  return __builtin_strlen(s);
+#else
+  return strlen(s);
+#endif
 }
 
+} // namespace folly
 #endif // FOLLY_PORTABILITY_H_