glslang/SPIRV/bitutils.h
Dennis Luxen fc89f065e9
Fix compiler warning emitted from GCC8
the following warning gets emitted:

```
In file included from ./Vulkan/glslang/SPIRV/hex_float.h:39,
                 from ./Vulkan/glslang/SPIRV/SpvBuilder.cpp:49:
./Vulkan/glslang/SPIRV/bitutils.h: In instantiation of ‘Dest spvutils::BitwiseCast(Src) [with Dest = spvutils::Float16; Src = short unsigned int]’:
./Vulkan/glslang/SPIRV/hex_float.h:138:47:   required from ‘T spvutils::FloatProxy<T>::getAsFloat() const [with T = spvutils::Float16]’
./Vulkan/glslang/SPIRV/hex_float.h:821:52:   required from here
./Vulkan/glslang/SPIRV/bitutils.h:29:14: warning: ‘void* memcpy(void*, const void*, size_t)’ writing to an object of non-trivially copyable type ‘class spvutils::Float16’; use copy-assignment or copy-initialization instead [-Wclass-memaccess]
   std::memcpy(&dest, &source, sizeof(dest));
   ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ./Vulkan/glslang/SPIRV/SpvBuilder.cpp:49:
./Vulkan/glslang/SPIRV/hex_float.h:43:7: note: ‘class spvutils::Float16’ declared here
 class Float16 {
       ^~~~~~~
In file included from ./Vulkan/glslang/SPIRV/hex_float.h:39,
                 from ./Vulkan/glslang/SPIRV/SpvBuilder.cpp:49:
./Vulkan/glslang/SPIRV/bitutils.h: In instantiation of ‘Dest spvutils::BitwiseCast(Src) [with Dest = spvutils::FloatProxy<spvutils::Float16>; Src = short unsigned int]’:
./Vulkan/glslang/SPIRV/hex_float.h:431:28:   required from ‘void spvutils::HexFloat<T, Traits>::setFromSignUnbiasedExponentAndNormalizedSignificand(bool, spvutils::HexFloat<T, Traits>::int_type, spvutils::HexFloat<T, Traits>::uint_type, bool) [with T = spvutils::FloatProxy<spvutils::Float16>; Traits = spvutils::HexFloatTraits<spvutils::FloatProxy<spvutils::Float16> >; spvutils::HexFloat<T, Traits>::int_type = short int; spvutils::HexFloat<T, Traits>::uint_type = short unsigned int]’
./Vulkan/glslang/SPIRV/hex_float.h:633:5:   required from ‘void spvutils::HexFloat<T, Traits>::castTo(other_T&, spvutils::round_direction) [with other_T = spvutils::HexFloat<spvutils::FloatProxy<spvutils::Float16>, spvutils::HexFloatTraits<spvutils::FloatProxy<spvutils::Float16> > >; T = spvutils::FloatProxy<float>; Traits = spvutils::HexFloatTraits<spvutils::FloatProxy<float> >]’
./Vulkan/glslang/SPIRV/hex_float.h:817:39:   required from here
./Vulkan/glslang/SPIRV/bitutils.h:29:14: warning: ‘void* memcpy(void*, const void*, size_t)’ copying an object of non-trivial type ‘class spvutils::FloatProxy<spvutils::Float16>’ from an array of ‘short unsigned int’ [-Wclass-memaccess]
   std::memcpy(&dest, &source, sizeof(dest));
   ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ./Vulkan/glslang/SPIRV/SpvBuilder.cpp:49:
./Vulkan/glslang/SPIRV/hex_float.h:115:7: note: ‘class spvutils::FloatProxy<spvutils::Float16>’ declared here
 class FloatProxy {
       ^~~~~~~~~~
```
2018-09-12 10:34:54 +02:00

82 lines
3.2 KiB
C++

// Copyright (c) 2015-2016 The Khronos Group Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef LIBSPIRV_UTIL_BITUTILS_H_
#define LIBSPIRV_UTIL_BITUTILS_H_
#include <cstdint>
#include <cstring>
namespace spvutils {
// Performs a bitwise copy of source to the destination type Dest.
template <typename Dest, typename Src>
Dest BitwiseCast(Src source) {
Dest dest;
static_assert(sizeof(source) == sizeof(dest),
"BitwiseCast: Source and destination must have the same size");
std::memcpy(static_cast<void*>(&dest), &source, sizeof(dest));
return dest;
}
// SetBits<T, First, Num> returns an integer of type <T> with bits set
// for position <First> through <First + Num - 1>, counting from the least
// significant bit. In particular when Num == 0, no positions are set to 1.
// A static assert will be triggered if First + Num > sizeof(T) * 8, that is,
// a bit that will not fit in the underlying type is set.
template <typename T, size_t First = 0, size_t Num = 0>
struct SetBits {
static_assert(First < sizeof(T) * 8,
"Tried to set a bit that is shifted too far.");
const static T get = (T(1) << First) | SetBits<T, First + 1, Num - 1>::get;
};
template <typename T, size_t Last>
struct SetBits<T, Last, 0> {
const static T get = T(0);
};
// This is all compile-time so we can put our tests right here.
static_assert(SetBits<uint32_t, 0, 0>::get == uint32_t(0x00000000),
"SetBits failed");
static_assert(SetBits<uint32_t, 0, 1>::get == uint32_t(0x00000001),
"SetBits failed");
static_assert(SetBits<uint32_t, 31, 1>::get == uint32_t(0x80000000),
"SetBits failed");
static_assert(SetBits<uint32_t, 1, 2>::get == uint32_t(0x00000006),
"SetBits failed");
static_assert(SetBits<uint32_t, 30, 2>::get == uint32_t(0xc0000000),
"SetBits failed");
static_assert(SetBits<uint32_t, 0, 31>::get == uint32_t(0x7FFFFFFF),
"SetBits failed");
static_assert(SetBits<uint32_t, 0, 32>::get == uint32_t(0xFFFFFFFF),
"SetBits failed");
static_assert(SetBits<uint32_t, 16, 16>::get == uint32_t(0xFFFF0000),
"SetBits failed");
static_assert(SetBits<uint64_t, 0, 1>::get == uint64_t(0x0000000000000001LL),
"SetBits failed");
static_assert(SetBits<uint64_t, 63, 1>::get == uint64_t(0x8000000000000000LL),
"SetBits failed");
static_assert(SetBits<uint64_t, 62, 2>::get == uint64_t(0xc000000000000000LL),
"SetBits failed");
static_assert(SetBits<uint64_t, 31, 1>::get == uint64_t(0x0000000080000000LL),
"SetBits failed");
static_assert(SetBits<uint64_t, 16, 16>::get == uint64_t(0x00000000FFFF0000LL),
"SetBits failed");
} // namespace spvutils
#endif // LIBSPIRV_UTIL_BITUTILS_H_