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glslang
Commit fa6e3c27 by David Neto Committed by Jeremy Hayes
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Add IntLog2 and use it

Replace uses of floating point log2 when we want an integer result from an integer operand. This avoids concerns about accuracy of floating point library functions.
parent 5c4f4211
Showing with 179 additions and 8 deletions
glslang/Include/Common.h
......@@ -286,6 +286,18 @@ template <class T> bool IsMultipleOfPow2(T number, int powerOf2)
return ! (number & (powerOf2 - 1));
}
// Returns log2 of an integer power of 2.
// T should be integral.
template <class T> int IntLog2(T n)
{
assert(IsPow2(n));
int result = 0;
while ((T(1) << result) != n) {
result++;
}
return result;
}
} // end namespace glslang
#endif // _COMMON_INCLUDED_
glslang/MachineIndependent/ParseHelper.cpp
......@@ -5469,14 +5469,7 @@ void TParseContext::setLayoutQualifier(const TSourceLoc& loc, TPublicType& publi
if (! IsPow2(value))
error(loc, "must be a power of 2", "buffer_reference_align", "");
else
#ifdef __ANDROID__
// Android NDK r15c tageting ABI 15 doesn't have full support for C++11
// (no std::exp2/log2). ::exp2 is available from C99 but ::log2 isn't
// available up until ABI 18 so we use the mathematical equivalent form
publicType.qualifier.layoutBufferReferenceAlign = (unsigned int)(std::log(value) / std::log(2.0));
#else
publicType.qualifier.layoutBufferReferenceAlign = (unsigned int)std::log2(value);
#endif
publicType.qualifier.layoutBufferReferenceAlign = IntLog2(value);
if (nonLiteral)
error(loc, "needs a literal integer", "buffer_reference_align", "");
return;
......
gtests/CMakeLists.txt
......@@ -47,6 +47,7 @@ if(BUILD_TESTING)
# Test related source files
${CMAKE_CURRENT_SOURCE_DIR}/AST.FromFile.cpp
${CMAKE_CURRENT_SOURCE_DIR}/BuiltInResource.FromFile.cpp
${CMAKE_CURRENT_SOURCE_DIR}/Common.cpp
${CMAKE_CURRENT_SOURCE_DIR}/Config.FromFile.cpp
${CMAKE_CURRENT_SOURCE_DIR}/HexFloat.cpp
${CMAKE_CURRENT_SOURCE_DIR}/Hlsl.FromFile.cpp
......
gtests/Common.cpp 0 → 100644
// Copyright (c) 2021 Google LLC
//
// 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.
#include <cstdint>
#include <gmock/gmock.h>
#include "glslang/Include/Common.h"
namespace {
TEST(IsPow2, Int_Negative) {
EXPECT_EQ(false, glslang::IsPow2(-5));
EXPECT_EQ(false, glslang::IsPow2(-1));
EXPECT_EQ(false, glslang::IsPow2(INT_MIN));
EXPECT_EQ(false, glslang::IsPow2(int64_t(-10)));
}
TEST(IsPow2, Zero) {
EXPECT_EQ(false, glslang::IsPow2(0));
EXPECT_EQ(false, glslang::IsPow2(0u));
EXPECT_EQ(false, glslang::IsPow2(0));
EXPECT_EQ(false, glslang::IsPow2(uint64_t(0)));
EXPECT_EQ(false, glslang::IsPow2(int64_t(0)));
}
TEST(IsPow2, Int_Positive_PowersOf2) {
EXPECT_EQ(true, glslang::IsPow2(1));
EXPECT_EQ(true, glslang::IsPow2(2));
EXPECT_EQ(true, glslang::IsPow2(4));
EXPECT_EQ(true, glslang::IsPow2(8));
EXPECT_EQ(true, glslang::IsPow2(16));
EXPECT_EQ(true, glslang::IsPow2(32768));
EXPECT_EQ(true, glslang::IsPow2(65536));
EXPECT_EQ(true, glslang::IsPow2(2147483648));
}
TEST(IsPow2, Int_Positive_NonPowersOf2) {
EXPECT_EQ(false, glslang::IsPow2(3));
EXPECT_EQ(false, glslang::IsPow2(5));
EXPECT_EQ(false, glslang::IsPow2(2147483647));
}
TEST(IsPow2, Uint_Positive_PowersOf2) {
EXPECT_EQ(true, glslang::IsPow2(1u));
EXPECT_EQ(true, glslang::IsPow2(2u));
EXPECT_EQ(true, glslang::IsPow2(4u));
EXPECT_EQ(true, glslang::IsPow2(8u));
EXPECT_EQ(true, glslang::IsPow2(16u));
EXPECT_EQ(true, glslang::IsPow2(32768u));
EXPECT_EQ(true, glslang::IsPow2(65536u));
EXPECT_EQ(true, glslang::IsPow2(2147483648u));
}
TEST(IsPow2, Uint_Positive_NonPowersOf2) {
EXPECT_EQ(false, glslang::IsPow2(3u));
EXPECT_EQ(false, glslang::IsPow2(5u));
EXPECT_EQ(false, glslang::IsPow2(2147483647u));
}
TEST(IntLog2, Int) {
EXPECT_EQ(0, glslang::IntLog2(1));
EXPECT_EQ(1, glslang::IntLog2(2));
EXPECT_EQ(2, glslang::IntLog2(4));
EXPECT_EQ(3, glslang::IntLog2(8));
EXPECT_EQ(4, glslang::IntLog2(16));
EXPECT_EQ(5, glslang::IntLog2(32));
EXPECT_EQ(6, glslang::IntLog2(64));
EXPECT_EQ(7, glslang::IntLog2(128));
EXPECT_EQ(8, glslang::IntLog2(256));
EXPECT_EQ(9, glslang::IntLog2(512));
EXPECT_EQ(10, glslang::IntLog2(1024));
EXPECT_EQ(11, glslang::IntLog2(2048));
EXPECT_EQ(12, glslang::IntLog2(0x1000));
EXPECT_EQ(13, glslang::IntLog2(0x2000));
EXPECT_EQ(14, glslang::IntLog2(0x4000));
EXPECT_EQ(15, glslang::IntLog2(0x8000));
EXPECT_EQ(16, glslang::IntLog2(0x10000));
EXPECT_EQ(17, glslang::IntLog2(0x20000));
EXPECT_EQ(18, glslang::IntLog2(0x40000));
EXPECT_EQ(19, glslang::IntLog2(0x80000));
EXPECT_EQ(20, glslang::IntLog2(0x100000));
EXPECT_EQ(21, glslang::IntLog2(0x200000));
EXPECT_EQ(22, glslang::IntLog2(0x400000));
EXPECT_EQ(23, glslang::IntLog2(0x800000));
EXPECT_EQ(24, glslang::IntLog2(0x1000000));
EXPECT_EQ(25, glslang::IntLog2(0x2000000));
EXPECT_EQ(26, glslang::IntLog2(0x4000000));
EXPECT_EQ(27, glslang::IntLog2(0x8000000));
EXPECT_EQ(28, glslang::IntLog2(0x10000000));
EXPECT_EQ(29, glslang::IntLog2(0x20000000));
EXPECT_EQ(30, glslang::IntLog2(0x40000000));
}
TEST(IntLog2, Uint) {
EXPECT_EQ(0, glslang::IntLog2(1u));
EXPECT_EQ(1, glslang::IntLog2(2u));
EXPECT_EQ(2, glslang::IntLog2(4u));
EXPECT_EQ(3, glslang::IntLog2(8u));
EXPECT_EQ(4, glslang::IntLog2(16u));
EXPECT_EQ(5, glslang::IntLog2(32u));
EXPECT_EQ(6, glslang::IntLog2(64u));
EXPECT_EQ(7, glslang::IntLog2(128u));
EXPECT_EQ(8, glslang::IntLog2(256u));
EXPECT_EQ(9, glslang::IntLog2(512u));
EXPECT_EQ(10, glslang::IntLog2(1024u));
EXPECT_EQ(11, glslang::IntLog2(2048u));
EXPECT_EQ(12, glslang::IntLog2(0x1000u));
EXPECT_EQ(13, glslang::IntLog2(0x2000u));
EXPECT_EQ(14, glslang::IntLog2(0x4000u));
EXPECT_EQ(15, glslang::IntLog2(0x8000u));
EXPECT_EQ(16, glslang::IntLog2(0x10000u));
EXPECT_EQ(17, glslang::IntLog2(0x20000u));
EXPECT_EQ(18, glslang::IntLog2(0x40000u));
EXPECT_EQ(19, glslang::IntLog2(0x80000u));
EXPECT_EQ(20, glslang::IntLog2(0x100000u));
EXPECT_EQ(21, glslang::IntLog2(0x200000u));
EXPECT_EQ(22, glslang::IntLog2(0x400000u));
EXPECT_EQ(23, glslang::IntLog2(0x800000u));
EXPECT_EQ(24, glslang::IntLog2(0x1000000u));
EXPECT_EQ(25, glslang::IntLog2(0x2000000u));
EXPECT_EQ(26, glslang::IntLog2(0x4000000u));
EXPECT_EQ(27, glslang::IntLog2(0x8000000u));
EXPECT_EQ(28, glslang::IntLog2(0x10000000u));
EXPECT_EQ(29, glslang::IntLog2(0x20000000u));
EXPECT_EQ(30, glslang::IntLog2(0x40000000u));
EXPECT_EQ(31, glslang::IntLog2(0x80000000u));
}
TEST(IntLog2, Int64) {
EXPECT_EQ(0, glslang::IntLog2(int64_t(1)));
EXPECT_EQ(1, glslang::IntLog2(int64_t(2)));
EXPECT_EQ(2, glslang::IntLog2(int64_t(4)));
EXPECT_EQ(3, glslang::IntLog2(int64_t(8)));
EXPECT_EQ(30, glslang::IntLog2(int64_t(0x40000000u)));
EXPECT_EQ(31, glslang::IntLog2(int64_t(0x80000000u)));
EXPECT_EQ(32, glslang::IntLog2(int64_t(0x10000) * int64_t(0x10000)));
EXPECT_EQ(48, glslang::IntLog2(int64_t(0x10000) * int64_t(0x10000) * int64_t(0x10000)));
EXPECT_EQ(62, glslang::IntLog2(int64_t(0x10000) * int64_t(0x10000) * int64_t(0x10000) * int64_t(0x4000)));
}
TEST(IntLog2, Uint64) {
EXPECT_EQ(0, glslang::IntLog2(uint64_t(1)));
EXPECT_EQ(1, glslang::IntLog2(uint64_t(2)));
EXPECT_EQ(2, glslang::IntLog2(uint64_t(4)));
EXPECT_EQ(3, glslang::IntLog2(uint64_t(8)));
EXPECT_EQ(30, glslang::IntLog2(uint64_t(0x40000000u)));
EXPECT_EQ(31, glslang::IntLog2(uint64_t(0x80000000u)));
EXPECT_EQ(32, glslang::IntLog2(uint64_t(0x10000) * uint64_t(0x10000)));
EXPECT_EQ(48, glslang::IntLog2(uint64_t(0x10000) * uint64_t(0x10000) * uint64_t(0x10000)));
EXPECT_EQ(62, glslang::IntLog2(uint64_t(0x10000) * uint64_t(0x10000) * uint64_t(0x10000) * uint64_t(0x4000)));
EXPECT_EQ(63, glslang::IntLog2(uint64_t(0x10000) * uint64_t(0x10000) * uint64_t(0x10000) * uint64_t(0x8000)));
}
} // anonymous namespace
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