X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FSupport%2FAlignOf.h;h=07da02d063c7d863b7848c83a5e9ca93398aa9cc;hb=8bd55b5451112a16df49711ec735f77a9a1a4f75;hp=979e5975aa001a310d33eece7c0bf05b15a20888;hpb=16c3b647eb100fe404ee65f106d563ddef6c74b7;p=oota-llvm.git

diff --git a/include/llvm/Support/AlignOf.h b/include/llvm/Support/AlignOf.h
index 979e5975aa0..07da02d063c 100644
--- a/include/llvm/Support/AlignOf.h
+++ b/include/llvm/Support/AlignOf.h
@@ -15,11 +15,21 @@
 #ifndef LLVM_SUPPORT_ALIGNOF_H
 #define LLVM_SUPPORT_ALIGNOF_H
 
-namespace llvm {
+#include "llvm/Support/Compiler.h"
+#include <cstddef>
 
+namespace llvm {
 template <typename T>
 struct AlignmentCalcImpl {
   char x;
+#if defined(_MSC_VER)
+// Disables "structure was padded due to __declspec(align())" warnings that are
+// generated by any class using AlignOf<T> with a manually specified alignment.
+// Although the warning is disabled in the LLVM project we need this pragma
+// as AlignOf.h is a published support header that's available for use
+// out-of-tree, and we would like that to compile cleanly at /W4.
+#pragma warning(suppress : 4324)
+#endif
   T t;
 private:
   AlignmentCalcImpl() {} // Never instantiate.
@@ -34,9 +44,18 @@ private:
 ///  compile-time constant (e.g., for template instantiation).
 template <typename T>
 struct AlignOf {
+#ifndef _MSC_VER
+  // Avoid warnings from GCC like:
+  //   comparison between 'enum llvm::AlignOf<X>::<anonymous>' and 'enum
+  //   llvm::AlignOf<Y>::<anonymous>' [-Wenum-compare]
+  // by using constexpr instead of enum.
+  // (except on MSVC, since it doesn't support constexpr yet).
+  static constexpr unsigned Alignment =
+      static_cast<unsigned int>(sizeof(AlignmentCalcImpl<T>) - sizeof(T));
+#else
   enum { Alignment =
          static_cast<unsigned int>(sizeof(AlignmentCalcImpl<T>) - sizeof(T)) };
-
+#endif
   enum { Alignment_GreaterEqual_2Bytes = Alignment >= 2 ? 1 : 0 };
   enum { Alignment_GreaterEqual_4Bytes = Alignment >= 4 ? 1 : 0 };
   enum { Alignment_GreaterEqual_8Bytes = Alignment >= 8 ? 1 : 0 };
@@ -46,15 +65,167 @@ struct AlignOf {
   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
+#ifndef _MSC_VER
+template <typename T> constexpr unsigned AlignOf<T>::Alignment;
+#endif
+
+/// 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.
 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 ten 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 ten types can
+/// be added at the cost of more boilerplate.
+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