third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/src/google/protobuf/stubs/port.h

Index: third_party/protobuf/src/google/protobuf/stubs/port.h
diff --git a/third_party/protobuf/src/google/protobuf/stubs/port.h b/third_party/protobuf/src/google/protobuf/stubs/port.h
index 80e60746531404a403c89661e3ff683034fddbbe..d1e5bee0a4aff09d5bb20d4a0700496f67a41703 100644
--- a/third_party/protobuf/src/google/protobuf/stubs/port.h
+++ b/third_party/protobuf/src/google/protobuf/stubs/port.h
@@ -60,8 +60,12 @@
   #endif
 #else
   #include <sys/param.h>   // __BYTE_ORDER
+  #if defined(__OpenBSD__)
+    #include <endian.h>
+  #endif
   #if ((defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)) || \
-         (defined(__BYTE_ORDER) && __BYTE_ORDER == __LITTLE_ENDIAN)) && \
+         (defined(__BYTE_ORDER) && __BYTE_ORDER == __LITTLE_ENDIAN) || \
+         (defined(BYTE_ORDER) && BYTE_ORDER == LITTLE_ENDIAN)) && \
       !defined(PROTOBUF_DISABLE_LITTLE_ENDIAN_OPT_FOR_TEST)
     #define PROTOBUF_LITTLE_ENDIAN 1
   #endif
@@ -125,12 +129,12 @@ typedef unsigned __int16 uint16;
 typedef unsigned __int32 uint32;
 typedef unsigned __int64 uint64;
 #else
-typedef int8_t  int8;
+typedef int8_t int8;
 typedef int16_t int16;
 typedef int32_t int32;
 typedef int64_t int64;
 
-typedef uint8_t  uint8;
+typedef uint8_t uint8;
 typedef uint16_t uint16;
 typedef uint32_t uint32;
 typedef uint64_t uint64;
@@ -147,8 +151,10 @@ typedef uint64_t uint64;
 #define GOOGLE_ULONGLONG(x) x##UI64
 #define GOOGLE_LL_FORMAT "I64"  // As in printf("%I64d", ...)
 #else
+// By long long, we actually mean int64.
 #define GOOGLE_LONGLONG(x) INT64_C(x)
 #define GOOGLE_ULONGLONG(x) UINT64_C(x)
+// Used to format real long long integers.
 #define GOOGLE_LL_FORMAT "ll"  // As in "%lld". Note that "q" is poor form also.
 #endif
 
@@ -190,6 +196,15 @@ static const uint64 kuint64max = GOOGLE_ULONGLONG(0xFFFFFFFFFFFFFFFF);
 #endif
 #endif
 
+#ifndef GOOGLE_ATTRIBUTE_NORETURN
+#ifdef __GNUC__
+// Tell the compiler that a given function never returns.
+#define GOOGLE_ATTRIBUTE_NORETURN __attribute__((noreturn))
+#else
+#define GOOGLE_ATTRIBUTE_NORETURN
+#endif
+#endif
+
 #ifndef GOOGLE_ATTRIBUTE_DEPRECATED
 #ifdef __GNUC__
 // If the method/variable/type is used anywhere, produce a warning.
@@ -292,10 +307,8 @@ inline void GOOGLE_UNALIGNED_STORE64(void *p, uint64 v) {
 #define GOOGLE_THREAD_LOCAL __thread
 #endif
 
-// The following guarantees declaration of the byte swap functions, and
-// defines __BYTE_ORDER for MSVC
+// The following guarantees declaration of the byte swap functions.
 #ifdef _MSC_VER
-#define __BYTE_ORDER __LITTLE_ENDIAN
 #define bswap_16(x) _byteswap_ushort(x)
 #define bswap_32(x) _byteswap_ulong(x)
 #define bswap_64(x) _byteswap_uint64(x)
@@ -334,6 +347,61 @@ static inline uint64 bswap_64(uint64 x) {
 #endif
 
 // ===================================================================
+// from google3/util/bits/bits.h
+
+class Bits {
+ public:
+  static uint32 Log2FloorNonZero(uint32 n) {
+#if defined(__GNUC__)
+  return 31 ^ __builtin_clz(n);
+#elif defined(COMPILER_MSVC) && defined(_M_IX86)
+  _asm {
+    bsr ebx, n
+    mov n, ebx
+  }
+  return n;
+#else
+  return Log2FloorNonZero_Portable(n);
+#endif
+  }
+
+  static uint64 Log2FloorNonZero64(uint64 n) {
+#if defined(__GNUC__)
+  return 63 ^ __builtin_clzll(n);
+#else
+  return Log2FloorNonZero64_Portable(n);
+#endif
+  }
+ private:
+  static int Log2FloorNonZero_Portable(uint32 n) {
+    if (n == 0)
+      return -1;
+    int log = 0;
+    uint32 value = n;
+    for (int i = 4; i >= 0; --i) {
+      int shift = (1 << i);
+      uint32 x = value >> shift;
+      if (x != 0) {
+        value = x;
+        log += shift;
+      }
+    }
+    assert(value == 1);
+    return log;
+  }
+
+  static int Log2FloorNonZero64_Portable(uint64 n) {
+    const uint32 topbits = static_cast<uint32>(n >> 32);
+    if (topbits == 0) {
+      // Top bits are zero, so scan in bottom bits
+      return Log2FloorNonZero(static_cast<uint32>(n));
+    } else {
+      return 32 + Log2FloorNonZero(topbits);
+    }
+  }
+};
+
+// ===================================================================
 // from google3/util/endian/endian.h
 LIBPROTOBUF_EXPORT uint32 ghtonl(uint32 x);