X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FSupport%2FEndian.h;h=bc93c9a66eef9a221a13ae534782c409ae06554e;hb=HEAD;hp=c98e2dc66cc16671aba39c973e571844c2d89796;hpb=523579e0758bfa5781b63eabdc079a3ff074c36a;p=oota-llvm.git

diff --git a/include/llvm/Support/Endian.h b/include/llvm/Support/Endian.h
index c98e2dc66cc..bc93c9a66ee 100644
--- a/include/llvm/Support/Endian.h
+++ b/include/llvm/Support/Endian.h
@@ -14,144 +14,218 @@
 #ifndef LLVM_SUPPORT_ENDIAN_H
 #define LLVM_SUPPORT_ENDIAN_H
 
-#include "llvm/Config/config.h"
-#include "llvm/System/SwapByteOrder.h"
-#include "llvm/Support/type_traits.h"
+#include "llvm/Support/AlignOf.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/SwapByteOrder.h"
 
 namespace llvm {
 namespace support {
+enum endianness {big, little, native};
 
-enum endianness {big, little};
-enum alignment {unaligned, aligned};
+// These are named values for common alignments.
+enum {aligned = 0, unaligned = 1};
 
-template<typename value_type, int host, int target>
-static typename enable_if_c<host == target, value_type>::type
-SwapByteOrderIfDifferent(value_type value) {
-  // Target endianess is the same as the host. Just pass the value through.
+namespace detail {
+  /// \brief ::value is either alignment, or alignof(T) if alignment is 0.
+  template<class T, int alignment>
+  struct PickAlignment {
+    enum {value = alignment == 0 ? AlignOf<T>::Alignment : alignment};
+  };
+} // end namespace detail
+
+namespace endian {
+/// Swap the bytes of value to match the given endianness.
+template<typename value_type, endianness endian>
+inline value_type byte_swap(value_type value) {
+  if (endian != native && sys::IsBigEndianHost != (endian == big))
+    sys::swapByteOrder(value);
   return value;
 }
 
-template<typename value_type, int host, int target>
-static typename enable_if_c<host != target, value_type>::type
-SwapByteOrderIfDifferent(value_type value) {
-    return sys::SwapByteOrder<value_type>(value);
+/// Read a value of a particular endianness from memory.
+template<typename value_type,
+         endianness endian,
+         std::size_t alignment>
+inline value_type read(const void *memory) {
+  value_type ret;
+
+  memcpy(&ret,
+         LLVM_ASSUME_ALIGNED(memory,
+           (detail::PickAlignment<value_type, alignment>::value)),
+         sizeof(value_type));
+  return byte_swap<value_type, endian>(ret);
 }
 
-namespace detail {
-
-template<typename value_type, alignment align>
-struct alignment_access_helper;
-
-template<typename value_type>
-struct alignment_access_helper<value_type, aligned>
-{
-  value_type val;
-};
-
-// Provides unaligned loads and stores.
-#pragma pack(push)
-#pragma pack(1)
-template<typename value_type>
-struct alignment_access_helper<value_type, unaligned>
-{
-  value_type val;
-};
-#pragma pack(pop)
-
-} // end namespace detail
+/// Read a value of a particular endianness from a buffer, and increment the
+/// buffer past that value.
+template<typename value_type, endianness endian, std::size_t alignment,
+         typename CharT>
+inline value_type readNext(const CharT *&memory) {
+  value_type ret = read<value_type, endian, alignment>(memory);
+  memory += sizeof(value_type);
+  return ret;
+}
 
-#if defined(LLVM_IS_HOST_BIG_ENDIAN) \
- || defined(_BIG_ENDIAN) || defined(__BIG_ENDIAN__)
-static const endianness host_endianness = big;
-#else
-static const endianness host_endianness = little;
-#endif
+/// Write a value to memory with a particular endianness.
+template<typename value_type,
+         endianness endian,
+         std::size_t alignment>
+inline void write(void *memory, value_type value) {
+  value = byte_swap<value_type, endian>(value);
+  memcpy(LLVM_ASSUME_ALIGNED(memory,
+           (detail::PickAlignment<value_type, alignment>::value)),
+         &value,
+         sizeof(value_type));
+}
 
-struct endian {
-  template<typename value_type, alignment align>
-  static value_type read_le(const void *memory) {
-    return SwapByteOrderIfDifferent<value_type, host_endianness, little>(
-      reinterpret_cast<const detail::alignment_access_helper
-        <value_type, align> *>(memory)->val);
+template <typename value_type>
+using make_unsigned_t = typename std::make_unsigned<value_type>::type;
+
+/// Read a value of a particular endianness from memory, for a location
+/// that starts at the given bit offset within the first byte.
+template <typename value_type, endianness endian, std::size_t alignment>
+inline value_type readAtBitAlignment(const void *memory, uint64_t startBit) {
+  assert(startBit < 8);
+  if (startBit == 0)
+    return read<value_type, endian, alignment>(memory);
+  else {
+    // Read two values and compose the result from them.
+    value_type val[2];
+    memcpy(&val[0],
+           LLVM_ASSUME_ALIGNED(
+               memory, (detail::PickAlignment<value_type, alignment>::value)),
+           sizeof(value_type) * 2);
+    val[0] = byte_swap<value_type, endian>(val[0]);
+    val[1] = byte_swap<value_type, endian>(val[1]);
+
+    // Shift bits from the lower value into place.
+    make_unsigned_t<value_type> lowerVal = val[0] >> startBit;
+    // Mask off upper bits after right shift in case of signed type.
+    make_unsigned_t<value_type> numBitsFirstVal =
+        (sizeof(value_type) * 8) - startBit;
+    lowerVal &= ((make_unsigned_t<value_type>)1 << numBitsFirstVal) - 1;
+
+    // Get the bits from the upper value.
+    make_unsigned_t<value_type> upperVal =
+        val[1] & (((make_unsigned_t<value_type>)1 << startBit) - 1);
+    // Shift them in to place.
+    upperVal <<= numBitsFirstVal;
+
+    return lowerVal | upperVal;
   }
+}
 
-  template<typename value_type, alignment align>
-  static void write_le(void *memory, value_type value) {
-    reinterpret_cast<detail::alignment_access_helper<value_type, align> *>
-      (memory)->val =
-        SwapByteOrderIfDifferent< value_type
-                                , host_endianness
-                                , little>(value);
+/// Write a value to memory with a particular endianness, for a location
+/// that starts at the given bit offset within the first byte.
+template <typename value_type, endianness endian, std::size_t alignment>
+inline void writeAtBitAlignment(void *memory, value_type value,
+                                uint64_t startBit) {
+  assert(startBit < 8);
+  if (startBit == 0)
+    write<value_type, endian, alignment>(memory, value);
+  else {
+    // Read two values and shift the result into them.
+    value_type val[2];
+    memcpy(&val[0],
+           LLVM_ASSUME_ALIGNED(
+               memory, (detail::PickAlignment<value_type, alignment>::value)),
+           sizeof(value_type) * 2);
+    val[0] = byte_swap<value_type, endian>(val[0]);
+    val[1] = byte_swap<value_type, endian>(val[1]);
+
+    // Mask off any existing bits in the upper part of the lower value that
+    // we want to replace.
+    val[0] &= ((make_unsigned_t<value_type>)1 << startBit) - 1;
+    make_unsigned_t<value_type> numBitsFirstVal =
+        (sizeof(value_type) * 8) - startBit;
+    make_unsigned_t<value_type> lowerVal = value;
+    if (startBit > 0) {
+      // Mask off the upper bits in the new value that are not going to go into
+      // the lower value. This avoids a left shift of a negative value, which
+      // is undefined behavior.
+      lowerVal &= (((make_unsigned_t<value_type>)1 << numBitsFirstVal) - 1);
+      // Now shift the new bits into place
+      lowerVal <<= startBit;
+    }
+    val[0] |= lowerVal;
+
+    // Mask off any existing bits in the lower part of the upper value that
+    // we want to replace.
+    val[1] &= ~(((make_unsigned_t<value_type>)1 << startBit) - 1);
+    // Next shift the bits that go into the upper value into position.
+    make_unsigned_t<value_type> upperVal = value >> numBitsFirstVal;
+    // Mask off upper bits after right shift in case of signed type.
+    upperVal &= ((make_unsigned_t<value_type>)1 << startBit) - 1;
+    val[1] |= upperVal;
+
+    // Finally, rewrite values.
+    val[0] = byte_swap<value_type, endian>(val[0]);
+    val[1] = byte_swap<value_type, endian>(val[1]);
+    memcpy(LLVM_ASSUME_ALIGNED(
+               memory, (detail::PickAlignment<value_type, alignment>::value)),
+           &val[0], sizeof(value_type) * 2);
   }
+}
+} // end namespace endian
 
-  template<typename value_type, alignment align>
-  static value_type read_be(const void *memory) {
-    return SwapByteOrderIfDifferent<value_type, host_endianness, big>(
-      reinterpret_cast<const detail::alignment_access_helper
-        <value_type, align> *>(memory)->val);
+namespace detail {
+template<typename value_type,
+         endianness endian,
+         std::size_t alignment>
+struct packed_endian_specific_integral {
+  operator value_type() const {
+    return endian::read<value_type, endian, alignment>(
+      (const void*)Value.buffer);
   }
 
-  template<typename value_type, alignment align>
-  static void write_be(void *memory, value_type value) {
-    reinterpret_cast<detail::alignment_access_helper
-      <value_type, align> *>(memory)->val =
-        SwapByteOrderIfDifferent< value_type
-                                , host_endianness
-                                , big>(value);
+  void operator=(value_type newValue) {
+    endian::write<value_type, endian, alignment>(
+      (void*)Value.buffer, newValue);
   }
-};
-
-namespace detail {
 
-template<typename value_type,
-         endianness target_endianness,
-         alignment target_alignment>
-class packed_endian_specific_integral;
+  packed_endian_specific_integral &operator+=(value_type newValue) {
+    *this = *this + newValue;
+    return *this;
+  }
 
-template<typename value_type>
-class packed_endian_specific_integral<value_type, little, unaligned> {
-public:
-  operator value_type() const {
-    return endian::read_le<value_type, unaligned>(Value);
+  packed_endian_specific_integral &operator-=(value_type newValue) {
+    *this = *this - newValue;
+    return *this;
   }
-private:
-  uint8_t Value[sizeof(value_type)];
-};
 
-template<typename value_type>
-class packed_endian_specific_integral<value_type, big, unaligned> {
-public:
-  operator value_type() const {
-    return endian::read_be<value_type, unaligned>(Value);
+  packed_endian_specific_integral &operator|=(value_type newValue) {
+    *this = *this | newValue;
+    return *this;
   }
-private:
-  uint8_t Value[sizeof(value_type)];
-};
 
-template<typename value_type>
-class packed_endian_specific_integral<value_type, little, aligned> {
-public:
-  operator value_type() const {
-    return endian::read_le<value_type, aligned>(&Value);
+  packed_endian_specific_integral &operator&=(value_type newValue) {
+    *this = *this & newValue;
+    return *this;
   }
+
 private:
-  value_type Value;
-};
+  AlignedCharArray<PickAlignment<value_type, alignment>::value,
+                   sizeof(value_type)> Value;
 
-template<typename value_type>
-class packed_endian_specific_integral<value_type, big, aligned> {
 public:
-  operator value_type() const {
-    return endian::read_be<value_type, aligned>(&Value);
-  }
-private:
-  value_type Value;
+  struct ref {
+    explicit ref(void *Ptr) : Ptr(Ptr) {}
+
+    operator value_type() const {
+      return endian::read<value_type, endian, alignment>(Ptr);
+    }
+
+    void operator=(value_type NewValue) {
+      endian::write<value_type, endian, alignment>(Ptr, NewValue);
+    }
+
+  private:
+    void *Ptr;
+  };
 };
 
 } // end namespace detail
 
-typedef detail::packed_endian_specific_integral
-                  <uint8_t, little, unaligned>  ulittle8_t;
 typedef detail::packed_endian_specific_integral
                   <uint16_t, little, unaligned> ulittle16_t;
 typedef detail::packed_endian_specific_integral
@@ -159,8 +233,6 @@ typedef detail::packed_endian_specific_integral
 typedef detail::packed_endian_specific_integral
                   <uint64_t, little, unaligned> ulittle64_t;
 
-typedef detail::packed_endian_specific_integral
-                   <int8_t, little, unaligned>  little8_t;
 typedef detail::packed_endian_specific_integral
                    <int16_t, little, unaligned> little16_t;
 typedef detail::packed_endian_specific_integral
@@ -168,8 +240,6 @@ typedef detail::packed_endian_specific_integral
 typedef detail::packed_endian_specific_integral
                    <int64_t, little, unaligned> little64_t;
 
-typedef detail::packed_endian_specific_integral
-                    <uint8_t, little, aligned>  aligned_ulittle8_t;
 typedef detail::packed_endian_specific_integral
                     <uint16_t, little, aligned> aligned_ulittle16_t;
 typedef detail::packed_endian_specific_integral
@@ -177,8 +247,6 @@ typedef detail::packed_endian_specific_integral
 typedef detail::packed_endian_specific_integral
                     <uint64_t, little, aligned> aligned_ulittle64_t;
 
-typedef detail::packed_endian_specific_integral
-                     <int8_t, little, aligned>  aligned_little8_t;
 typedef detail::packed_endian_specific_integral
                      <int16_t, little, aligned> aligned_little16_t;
 typedef detail::packed_endian_specific_integral
@@ -186,8 +254,6 @@ typedef detail::packed_endian_specific_integral
 typedef detail::packed_endian_specific_integral
                      <int64_t, little, aligned> aligned_little64_t;
 
-typedef detail::packed_endian_specific_integral
-                  <uint8_t, big, unaligned>     ubig8_t;
 typedef detail::packed_endian_specific_integral
                   <uint16_t, big, unaligned>    ubig16_t;
 typedef detail::packed_endian_specific_integral
@@ -195,8 +261,6 @@ typedef detail::packed_endian_specific_integral
 typedef detail::packed_endian_specific_integral
                   <uint64_t, big, unaligned>    ubig64_t;
 
-typedef detail::packed_endian_specific_integral
-                   <int8_t, big, unaligned>     big8_t;
 typedef detail::packed_endian_specific_integral
                    <int16_t, big, unaligned>    big16_t;
 typedef detail::packed_endian_specific_integral
@@ -204,8 +268,6 @@ typedef detail::packed_endian_specific_integral
 typedef detail::packed_endian_specific_integral
                    <int64_t, big, unaligned>    big64_t;
 
-typedef detail::packed_endian_specific_integral
-                    <uint8_t, big, aligned>     aligned_ubig8_t;
 typedef detail::packed_endian_specific_integral
                     <uint16_t, big, aligned>    aligned_ubig16_t;
 typedef detail::packed_endian_specific_integral
@@ -213,8 +275,6 @@ typedef detail::packed_endian_specific_integral
 typedef detail::packed_endian_specific_integral
                     <uint64_t, big, aligned>    aligned_ubig64_t;
 
-typedef detail::packed_endian_specific_integral
-                     <int8_t, big, aligned>     aligned_big8_t;
 typedef detail::packed_endian_specific_integral
                      <int16_t, big, aligned>    aligned_big16_t;
 typedef detail::packed_endian_specific_integral
@@ -222,7 +282,64 @@ typedef detail::packed_endian_specific_integral
 typedef detail::packed_endian_specific_integral
                      <int64_t, big, aligned>    aligned_big64_t;
 
-} // end namespace llvm
+typedef detail::packed_endian_specific_integral
+                  <uint16_t, native, unaligned> unaligned_uint16_t;
+typedef detail::packed_endian_specific_integral
+                  <uint32_t, native, unaligned> unaligned_uint32_t;
+typedef detail::packed_endian_specific_integral
+                  <uint64_t, native, unaligned> unaligned_uint64_t;
+
+typedef detail::packed_endian_specific_integral
+                   <int16_t, native, unaligned> unaligned_int16_t;
+typedef detail::packed_endian_specific_integral
+                   <int32_t, native, unaligned> unaligned_int32_t;
+typedef detail::packed_endian_specific_integral
+                   <int64_t, native, unaligned> unaligned_int64_t;
+
+namespace endian {
+template <typename T, endianness E> inline T read(const void *P) {
+  return *(const detail::packed_endian_specific_integral<T, E, unaligned> *)P;
+}
+
+template <endianness E> inline uint16_t read16(const void *P) {
+  return read<uint16_t, E>(P);
+}
+template <endianness E> inline uint32_t read32(const void *P) {
+  return read<uint32_t, E>(P);
+}
+template <endianness E> inline uint64_t read64(const void *P) {
+  return read<uint64_t, E>(P);
+}
+
+inline uint16_t read16le(const void *P) { return read16<little>(P); }
+inline uint32_t read32le(const void *P) { return read32<little>(P); }
+inline uint64_t read64le(const void *P) { return read64<little>(P); }
+inline uint16_t read16be(const void *P) { return read16<big>(P); }
+inline uint32_t read32be(const void *P) { return read32<big>(P); }
+inline uint64_t read64be(const void *P) { return read64<big>(P); }
+
+template <typename T, endianness E> inline void write(void *P, T V) {
+  *(detail::packed_endian_specific_integral<T, E, unaligned> *)P = V;
+}
+
+template <endianness E> inline void write16(void *P, uint16_t V) {
+  write<uint16_t, E>(P, V);
+}
+template <endianness E> inline void write32(void *P, uint32_t V) {
+  write<uint32_t, E>(P, V);
+}
+template <endianness E> inline void write64(void *P, uint64_t V) {
+  write<uint64_t, E>(P, V);
+}
+
+inline void write16le(void *P, uint16_t V) { write16<little>(P, V); }
+inline void write32le(void *P, uint32_t V) { write32<little>(P, V); }
+inline void write64le(void *P, uint64_t V) { write64<little>(P, V); }
+inline void write16be(void *P, uint16_t V) { write16<big>(P, V); }
+inline void write32be(void *P, uint32_t V) { write32<big>(P, V); }
+inline void write64be(void *P, uint64_t V) { write64<big>(P, V); }
+} // end namespace endian
 } // end namespace support
+} // end namespace llvm
 
 #endif