The TargetData is not used for the isPowerOfTwo determination. It has never

[oota-llvm.git] / include / llvm / Support / AlignOf.h

diff --git a/include/llvm/Support/AlignOf.h b/include/llvm/Support/AlignOf.h
index cf7125173ee1e48efb0de076af102ad8e6d24093..d6b0ab8b3750f2a786ec53d7112de40b1b290963 100644 (file)
--- a/include/llvm/Support/AlignOf.h
+++ b/include/llvm/Support/AlignOf.h
@@ -68,24 +68,20 @@ inline unsigned alignOf() { return AlignOf<T>::Alignment; }
 /// integer literal can be used to specify an alignment constraint. Once built
 /// up here, we can then begin to indirect between these using normal C++
 /// template parameters.
-template <size_t Alignment> struct AlignedCharArrayImpl {};
-template <> struct AlignedCharArrayImpl<0> {
-  typedef char type;
-};
+template <size_t Alignment> struct AlignedCharArrayImpl;
+
+// MSVC requires special handling here.
+#ifndef _MSC_VER
+
 #if __has_feature(cxx_alignas)
 #define LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(x) \
   template <> struct AlignedCharArrayImpl<x> { \
-    typedef char alignas(x) type; \
+    char alignas(x) aligned; \
   }
-#elif defined(__clang__) || defined(__GNUC__)
+#elif defined(__GNUC__) || defined(__IBM_ATTRIBUTES)
 #define LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(x) \
   template <> struct AlignedCharArrayImpl<x> { \
-    typedef char type __attribute__((aligned(x))); \
-  }
-#elif defined(_MSC_VER)
-#define LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(x) \
-  template <> struct AlignedCharArrayImpl<x> { \
-    typedef __declspec(align(x)) char type; \
+    char aligned __attribute__((aligned(x))); \
   }
 #else
 # error No supported align as directive.
@@ -104,9 +100,38 @@ LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(1024);
 LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(2048);
 LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(4096);
 LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(8192);
+
+#undef LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT
+
+#else // _MSC_VER
+
+// We provide special variations of this template for the most common
+// alignments because __declspec(align(...)) doesn't actually work when it is
+// a member of a by-value function argument in MSVC, even if the alignment
+// request is something reasonably like 8-byte or 16-byte.
+template <> struct AlignedCharArrayImpl<1> { char aligned; };
+template <> struct AlignedCharArrayImpl<2> { short aligned; };
+template <> struct AlignedCharArrayImpl<4> { int aligned; };
+template <> struct AlignedCharArrayImpl<8> { double aligned; };
+
+#define LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(x) \
+  template <> struct AlignedCharArrayImpl<x> { \
+    __declspec(align(x)) char aligned; \
+  }
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(16);
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(32);
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(64);
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(128);
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(512);
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(1024);
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(2048);
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(4096);
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(8192);
 // Any larger and MSVC complains.
 #undef LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT
 
+#endif // _MSC_VER
+
 /// \brief This union template exposes a suitably aligned and sized character
 /// array member which can hold elements of any of up to four types.
 ///
@@ -134,17 +159,11 @@ public:
   /// constrain the layout of this character array.
   char buffer[sizeof(SizerImpl)];
 
-  // Sadly, Clang and GCC both fail to align a character array properly even
-  // with an explicit alignment attribute. To work around this, we union
-  // the character array that will actually be used with a struct that contains
-  // a single aligned character member. Tests seem to indicate that both Clang
-  // and GCC will properly register the alignment of a struct containing an
-  // aligned member, and this alignment should carry over to the character
-  // array in the union.
-  struct {
-    typename llvm::AlignedCharArrayImpl<AlignOf<AlignerImpl>::Alignment>::type
-      nonce_inner_member;
-  } nonce_member;
+private:
+  // Tests seem to indicate that both Clang and GCC will properly register the
+  // alignment of a struct containing an aligned member, and this alignment
+  // should carry over to the character array in the union.
+  llvm::AlignedCharArrayImpl<AlignOf<AlignerImpl>::Alignment> nonce_member;
 };
 
 } // end namespace llvm