Make fbstring libgcc-safe

[folly.git] / folly / Bits.h

diff --git a/folly/Bits.h b/folly/Bits.h
index 2b5225243ea74c2db0c54793879487a700ff7a52..78160533959ab4b7b43b84e8917ef9a20da907d7 100644 (file)
--- a/folly/Bits.h
+++ b/folly/Bits.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 Facebook, Inc.
+ * Copyright 2014 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -61,6 +61,13 @@
 #error GCC required
 #endif
 
+#ifndef __clang__
+#define FOLLY_INTRINSIC_CONSTEXPR constexpr
+#else
+// Unlike GCC, in Clang (as of 3.2) intrinsics aren't constexpr.
+#define FOLLY_INTRINSIC_CONSTEXPR const
+#endif
+
 #ifndef FOLLY_NO_CONFIG
 #include "folly/folly-config.h"
 #endif
@@ -86,7 +93,7 @@ namespace folly {
 // Generate overloads for findFirstSet as wrappers around
 // appropriate ffs, ffsl, ffsll gcc builtins
 template <class T>
-inline constexpr
+inline FOLLY_INTRINSIC_CONSTEXPR
 typename std::enable_if<
   (std::is_integral<T>::value &&
    std::is_unsigned<T>::value &&
@@ -97,7 +104,7 @@ typename std::enable_if<
 }
 
 template <class T>
-inline constexpr
+inline FOLLY_INTRINSIC_CONSTEXPR
 typename std::enable_if<
   (std::is_integral<T>::value &&
    std::is_unsigned<T>::value &&
@@ -109,7 +116,7 @@ typename std::enable_if<
 }
 
 template <class T>
-inline constexpr
+inline FOLLY_INTRINSIC_CONSTEXPR
 typename std::enable_if<
   (std::is_integral<T>::value &&
    std::is_unsigned<T>::value &&
@@ -121,7 +128,7 @@ typename std::enable_if<
 }
 
 template <class T>
-inline constexpr
+inline FOLLY_INTRINSIC_CONSTEXPR
 typename std::enable_if<
   (std::is_integral<T>::value && std::is_signed<T>::value),
   unsigned int>::type
@@ -135,7 +142,7 @@ typename std::enable_if<
 // findLastSet: return the 1-based index of the highest bit set
 // for x > 0, findLastSet(x) == 1 + floor(log2(x))
 template <class T>
-inline constexpr
+inline FOLLY_INTRINSIC_CONSTEXPR
 typename std::enable_if<
   (std::is_integral<T>::value &&
    std::is_unsigned<T>::value &&
@@ -146,7 +153,7 @@ typename std::enable_if<
 }
 
 template <class T>
-inline constexpr
+inline FOLLY_INTRINSIC_CONSTEXPR
 typename std::enable_if<
   (std::is_integral<T>::value &&
    std::is_unsigned<T>::value &&
@@ -158,7 +165,7 @@ typename std::enable_if<
 }
 
 template <class T>
-inline constexpr
+inline FOLLY_INTRINSIC_CONSTEXPR
 typename std::enable_if<
   (std::is_integral<T>::value &&
    std::is_unsigned<T>::value &&
@@ -170,7 +177,7 @@ typename std::enable_if<
 }
 
 template <class T>
-inline constexpr
+inline FOLLY_INTRINSIC_CONSTEXPR
 typename std::enable_if<
   (std::is_integral<T>::value &&
    std::is_signed<T>::value),
@@ -180,7 +187,7 @@ typename std::enable_if<
 }
 
 template <class T>
-inline constexpr
+inline FOLLY_INTRINSIC_CONSTEXPR
 typename std::enable_if<
   std::is_integral<T>::value && std::is_unsigned<T>::value,
   T>::type
@@ -378,11 +385,14 @@ class BitIterator
    * Construct a BitIterator that points at a given bit offset (default 0)
    * in iter.
    */
+  #pragma GCC diagnostic push // bitOffset shadows a member
+  #pragma GCC diagnostic ignored "-Wshadow"
   explicit BitIterator(const BaseIter& iter, size_t bitOffset=0)
     : bititerator_detail::BitIteratorBase<BaseIter>::type(iter),
       bitOffset_(bitOffset) {
     assert(bitOffset_ < bitsPerBlock());
   }
+  #pragma GCC diagnostic pop
 
   size_t bitOffset() const {
     return bitOffset_;
@@ -514,6 +524,7 @@ template <class T, class Enable=void> struct Unaligned;
 /**
  * Representation of an unaligned value of a POD type.
  */
+FOLLY_PACK_PUSH
 template <class T>
 struct Unaligned<
     T,
@@ -521,7 +532,8 @@ struct Unaligned<
   Unaligned() = default;  // uninitialized
   /* implicit */ Unaligned(T v) : value(v) { }
   T value;
-} __attribute__((packed));
+} FOLLY_PACK_ATTR;
+FOLLY_PACK_POP
 
 /**
  * Read an unaligned value of type T and return it.
@@ -546,4 +558,3 @@ inline void storeUnaligned(void* p, T value) {
 }  // namespace folly
 
 #endif /* FOLLY_BITS_H_ */
-