X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FSupport%2FAlignOf.h;h=061d5acf2322b570ad197b753db150d10c2f1b4b;hb=7610ba7d241256653b7225245d439646cc1450e5;hp=108c59f0eb40de7b5087a697600b206441747fcd;hpb=9d695d5f7d31e912a2be74229b3e2baab2564820;p=oota-llvm.git

diff --git a/include/llvm/Support/AlignOf.h b/include/llvm/Support/AlignOf.h
index 108c59f0eb4..061d5acf232 100644
--- a/include/llvm/Support/AlignOf.h
+++ b/include/llvm/Support/AlignOf.h
@@ -15,8 +15,10 @@
 #ifndef LLVM_SUPPORT_ALIGNOF_H
 #define LLVM_SUPPORT_ALIGNOF_H
 
+#include "llvm/Support/Compiler.h"
+#include <cstddef>
+
 namespace llvm {
-  
 template <typename T>
 struct AlignmentCalcImpl {
   char x;
@@ -24,7 +26,7 @@ struct AlignmentCalcImpl {
 private:
   AlignmentCalcImpl() {} // Never instantiate.
 };
-  
+
 /// AlignOf - A templated class that contains an enum value representing
 ///  the alignment of the template argument.  For example,
 ///  AlignOf<int>::Alignment represents the alignment of type "int".  The
@@ -34,26 +36,175 @@ private:
 ///  compile-time constant (e.g., for template instantiation).
 template <typename T>
 struct AlignOf {
-  enum { Alignment = sizeof(AlignmentCalcImpl<T>) - sizeof(T) };
+  enum { Alignment =
+         static_cast<unsigned int>(sizeof(AlignmentCalcImpl<T>) - sizeof(T)) };
 
   enum { Alignment_GreaterEqual_2Bytes = Alignment >= 2 ? 1 : 0 };
   enum { Alignment_GreaterEqual_4Bytes = Alignment >= 4 ? 1 : 0 };
   enum { Alignment_GreaterEqual_8Bytes = Alignment >= 8 ? 1 : 0 };
   enum { Alignment_GreaterEqual_16Bytes = Alignment >= 16 ? 1 : 0 };
-  
+
   enum { Alignment_LessEqual_2Bytes = Alignment <= 2 ? 1 : 0 };
-  enum { Alignment_LessEqual_4Bytes = Alignment <= 4 ? 1 : 0 }; 
+  enum { Alignment_LessEqual_4Bytes = Alignment <= 4 ? 1 : 0 };
   enum { Alignment_LessEqual_8Bytes = Alignment <= 8 ? 1 : 0 };
   enum { Alignment_LessEqual_16Bytes = Alignment <= 16 ? 1 : 0 };
-
 };
 
-/// alignof - A templated function that returns the mininum alignment of
+/// alignOf - A templated function that returns the minimum alignment of
 ///  of a type.  This provides no extra functionality beyond the AlignOf
 ///  class besides some cosmetic cleanliness.  Example usage:
-///  alignof<int>() returns the alignment of an int.
+///  alignOf<int>() returns the alignment of an int.
 template <typename T>
-static inline unsigned alignof() { return AlignOf<T>::Alignment; }
-  
+inline unsigned alignOf() { return AlignOf<T>::Alignment; }
+
+/// \struct AlignedCharArray
+/// \brief Helper for building an aligned character array type.
+///
+/// This template is used to explicitly build up a collection of aligned
+/// character array types. We have to build these up using a macro and explicit
+/// specialization to cope with old versions of MSVC and GCC where only an
+/// 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.
+
+// MSVC requires special handling here.
+#ifndef _MSC_VER
+
+#if __has_feature(cxx_alignas)
+template<std::size_t Alignment, std::size_t Size>
+struct AlignedCharArray {
+  alignas(Alignment) char buffer[Size];
+};
+
+#elif defined(__GNUC__) || defined(__IBM_ATTRIBUTES)
+/// \brief Create a type with an aligned char buffer.
+template<std::size_t Alignment, std::size_t Size>
+struct AlignedCharArray;
+
+#define LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(x) \
+  template<std::size_t Size> \
+  struct AlignedCharArray<x, Size> { \
+    __attribute__((aligned(x))) char buffer[Size]; \
+  };
+
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(1)
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(2)
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(4)
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(8)
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(16)
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(32)
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(64)
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(128)
+
+#undef LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT
+
+#else
+# error No supported align as directive.
+#endif
+
+#else // _MSC_VER
+
+/// \brief Create a type with an aligned char buffer.
+template<std::size_t Alignment, std::size_t Size>
+struct AlignedCharArray;
+
+// 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. Note that we can't
+// even include the declspec with the union that forces the alignment because
+// MSVC warns on the existence of the declspec despite the union member forcing
+// proper alignment.
+
+template<std::size_t Size>
+struct AlignedCharArray<1, Size> {
+  union {
+    char aligned;
+    char buffer[Size];
+  };
+};
+
+template<std::size_t Size>
+struct AlignedCharArray<2, Size> {
+  union {
+    short aligned;
+    char buffer[Size];
+  };
+};
+
+template<std::size_t Size>
+struct AlignedCharArray<4, Size> {
+  union {
+    int aligned;
+    char buffer[Size];
+  };
+};
+
+template<std::size_t Size>
+struct AlignedCharArray<8, Size> {
+  union {
+    double aligned;
+    char buffer[Size];
+  };
+};
+
+
+// The rest of these are provided with a __declspec(align(...)) and we simply
+// can't pass them by-value as function arguments on MSVC.
+
+#define LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(x) \
+  template<std::size_t Size> \
+  struct AlignedCharArray<x, Size> { \
+    __declspec(align(x)) char buffer[Size]; \
+  };
+
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(16)
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(32)
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(64)
+LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(128)
+
+#undef LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT
+
+#endif // _MSC_VER
+
+namespace detail {
+template <typename T1,
+          typename T2 = char, typename T3 = char, typename T4 = char,
+          typename T5 = char, typename T6 = char, typename T7 = char,
+          typename T8 = char, typename T9 = char, typename T10 = char>
+class AlignerImpl {
+  T1 t1; T2 t2; T3 t3; T4 t4; T5 t5; T6 t6; T7 t7; T8 t8; T9 t9; T10 t10;
+
+  AlignerImpl(); // Never defined or instantiated.
+};
+
+template <typename T1,
+          typename T2 = char, typename T3 = char, typename T4 = char,
+          typename T5 = char, typename T6 = char, typename T7 = char,
+          typename T8 = char, typename T9 = char, typename T10 = char>
+union SizerImpl {
+  char arr1[sizeof(T1)], arr2[sizeof(T2)], arr3[sizeof(T3)], arr4[sizeof(T4)],
+       arr5[sizeof(T5)], arr6[sizeof(T6)], arr7[sizeof(T7)], arr8[sizeof(T8)],
+       arr9[sizeof(T9)], arr10[sizeof(T10)];
+};
+} // end namespace detail
+
+/// \brief This union template exposes a suitably aligned and sized character
+/// array member which can hold elements of any of up to four types.
+///
+/// These types may be arrays, structs, or any other types. The goal is to
+/// expose a char array buffer member which can be used as suitable storage for
+/// a placement new of any of these types. Support for more than seven types can
+/// be added at the cost of more boiler plate.
+template <typename T1,
+          typename T2 = char, typename T3 = char, typename T4 = char,
+          typename T5 = char, typename T6 = char, typename T7 = char,
+          typename T8 = char, typename T9 = char, typename T10 = char>
+struct AlignedCharArrayUnion : llvm::AlignedCharArray<
+    AlignOf<detail::AlignerImpl<T1, T2, T3, T4, T5,
+                                T6, T7, T8, T9, T10> >::Alignment,
+    sizeof(detail::SizerImpl<T1, T2, T3, T4, T5,
+                             T6, T7, T8, T9, T10>)> {
+};
 } // end namespace llvm
 #endif