sketch SkVx
Change-Id: I1cb8113af243ed6327179d295835295834a752aa
Reviewed-on: https://skia-review.googlesource.com/c/189581
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
diff --git a/gn/tests.gni b/gn/tests.gni
index 412da6d..4df8bae 100644
--- a/gn/tests.gni
+++ b/gn/tests.gni
@@ -241,6 +241,7 @@
"$_tests/SkSLMetalTest.cpp",
"$_tests/SkSLSPIRVTest.cpp",
"$_tests/SkUTFTest.cpp",
+ "$_tests/SkVxTest.cpp",
"$_tests/SortTest.cpp",
"$_tests/SpecialImageTest.cpp",
"$_tests/SpecialSurfaceTest.cpp",
diff --git a/include/private/SkVx.h b/include/private/SkVx.h
new file mode 100644
index 0000000..d233965
--- /dev/null
+++ b/include/private/SkVx.h
@@ -0,0 +1,213 @@
+/*
+ * Copyright 2019 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SKVX_DEFINED
+#define SKVX_DEFINED
+
+// skvx::Vec<N,T> are SIMD vectors of N T's, a v1.5 successor to SkNx<N,T>.
+//
+// This time we're leaning a bit less on platform-specific intrinsics and a bit
+// more on Clang/GCC vector extensions, but still keeping the option open to
+// drop in platform-specific intrinsics, actually more easily than before.
+//
+// We've also fixed a few of the caveats that used to make SkNx awkward to work
+// with across translation units. skvx::Vec<N,T> always has N*sizeof(T) size
+// and alignof(T) alignment and is safe to use across translation units freely.
+
+
+// It'd be nice to not pull in any Skia headers here, in case we want to spin this file off.
+#include <algorithm> // std::accumulate, std::copy, std::fill, std::transform, etc.
+#include <cstdint> // intXX_t
+#include <cstring> // memcpy()
+#include <functional> // std::plus, std::minus, std::multiplies, etc.
+#include <initializer_list> // std::initializer_list
+
+// We try to use <algorithm> and <functional> where natural so that the more
+// idiosyncratic parts that can't use them stand out. This is an experiment.
+
+namespace skvx {
+
+// All Vec have the same simple memory layout, the same as `T vec[N]`.
+// This gives Vec a consistent ABI, letting them pass between files compiled with
+// different instruction sets (e.g. SSE2 and AVX2) without fear of ODR violation.
+template <int N, typename T>
+struct Vec {
+ static_assert((N & (N-1)) == 0, "N must be a power of 2.");
+
+ T vals[N];
+
+ Vec() = default;
+
+ Vec(T x) { std::fill(vals,vals+N, x); }
+
+ Vec(std::initializer_list<T> xs) : Vec(0) {
+ std::copy(xs.begin(), xs.begin() + std::min(xs.size(), (size_t)N), vals);
+ }
+
+ T operator[](int i) const { return vals[i]; }
+ T& operator[](int i) { return vals[i]; }
+};
+
+
+#if defined(_MSC_VER)
+ #define ALWAYS_INLINE __forceinline
+#else
+ #define ALWAYS_INLINE __attribute__((always_inline))
+#endif
+
+// Helps tamp down on the repetitive boilerplate.
+#define ___ template <int N, typename T> static inline ALWAYS_INLINE
+
+#if defined(__GNUC__) && !defined(__clang__) && defined(__SSE__)
+ // GCC warns about ABI changes when returning >= 32 byte vectors when -mavx is not enabled.
+ // The functions that do that (BitPun::operator U() and vext()) are marked ALWAYS_INLINE,
+ // so we can just stifle the warning.
+ #pragma GCC diagnostic ignored "-Wpsabi"
+#endif
+
+// BitPun<V> holds a V and can implicitly bit-pun that V to any other equal sized type U.
+template <typename V>
+struct BitPun {
+ V v;
+
+ template <typename U>
+ ALWAYS_INLINE operator U() const {
+ static_assert(sizeof(U) == sizeof(V), "");
+ U u;
+ memcpy(&u, &v, sizeof(U));
+ return u;
+ }
+};
+template <typename V>
+static inline ALWAYS_INLINE BitPun<V> bit_pun(V v) { return {v}; }
+
+// Translate from a value type T to its corresponding Mask, the result of a comparison.
+template <typename T> struct Mask { using type = T; };
+template <> struct Mask<float > { using type = int32_t; };
+template <> struct Mask<double> { using type = int64_t; };
+template <typename T> using mask = typename Mask<T>::type;
+
+
+// Apply op() to each lane of one or two input vectors, returning a new vector of the results.
+template <int N, typename T, typename Op>
+static inline auto map(Vec<N,T> x, Op op) -> Vec<N, decltype(op(x[0]))> {
+ Vec<N, decltype(op(x[0]))> results;
+ std::transform(x.vals, x.vals+N, results.vals, op);
+ return results;
+}
+template <int N, typename T, typename Op>
+static inline auto map(Vec<N,T> x, Vec<N,T> y, Op op) -> Vec<N, decltype(op(x[0], y[0]))> {
+ Vec<N, decltype(op(x[0], y[0]))> results;
+ std::transform(x.vals, x.vals+N, y.vals, results.vals, op);
+ return results;
+}
+
+
+// We have two default strategies for implementing most operations:
+// 1) lean on Clang/GCC vector extensions when available;
+// 2) fall back to portable implementations when not.
+// At the end we can drop in platform-specific implementations that override these defaults.
+
+#if 1 && !defined(SKNX_NO_SIMD) && (defined(__clang__) || defined(__GNUC__))
+
+ // VExt<N,T> types have the same size as Vec<N,T> and support most operations directly.
+ // N.B. VExt<N,T> alignment is N*alignof(T), stricter than Vec<N,T>'s alignof(T).
+
+ #if defined(__clang__)
+ template <int N, typename T>
+ using VExt = T __attribute__((ext_vector_type(N)));
+
+ #elif defined(__GNUC__)
+ template <int N, typename T>
+ struct VExtHelper {
+ typedef T __attribute__((vector_size(N*sizeof(T)))) type;
+ };
+
+ template <int N, typename T>
+ using VExt = typename VExtHelper<N,T>::type;
+ #endif
+
+ ___ VExt<N,T> vext(Vec<N,T> v) { return bit_pun(v); }
+
+ ___ Vec<N,T> operator+(Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) + vext(y)); }
+ ___ Vec<N,T> operator-(Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) - vext(y)); }
+ ___ Vec<N,T> operator*(Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) * vext(y)); }
+ ___ Vec<N,T> operator/(Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) / vext(y)); }
+
+ ___ Vec<N,T> operator^(Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) ^ vext(y)); }
+ ___ Vec<N,T> operator&(Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) & vext(y)); }
+ ___ Vec<N,T> operator|(Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) | vext(y)); }
+
+ ___ Vec<N,T> operator!(Vec<N,T> x) { return bit_pun(!vext(x)); }
+ ___ Vec<N,T> operator-(Vec<N,T> x) { return bit_pun(-vext(x)); }
+ ___ Vec<N,T> operator~(Vec<N,T> x) { return bit_pun(~vext(x)); }
+
+ ___ Vec<N,T> operator<<(Vec<N,T> x, int bits) { return bit_pun(vext(x) << bits); }
+ ___ Vec<N,T> operator>>(Vec<N,T> x, int bits) { return bit_pun(vext(x) >> bits); }
+
+ ___ Vec<N, mask<T>> operator==(Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) == vext(y)); }
+ ___ Vec<N, mask<T>> operator!=(Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) != vext(y)); }
+ ___ Vec<N, mask<T>> operator<=(Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) <= vext(y)); }
+ ___ Vec<N, mask<T>> operator>=(Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) >= vext(y)); }
+ ___ Vec<N, mask<T>> operator< (Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) < vext(y)); }
+ ___ Vec<N, mask<T>> operator> (Vec<N,T> x, Vec<N,T> y) { return bit_pun(vext(x) > vext(y)); }
+
+#else
+
+ // Either SKNX_NO_SIMD is defined, or Clang/GCC vector extensions are not available.
+ // We'll implement things portably, in a way that should be easily autovectorizable.
+
+ ___ Vec<N,T> operator+(Vec<N,T> x, Vec<N,T> y) { return map(x,y, std::plus <T>{}); }
+ ___ Vec<N,T> operator-(Vec<N,T> x, Vec<N,T> y) { return map(x,y, std::minus <T>{}); }
+ ___ Vec<N,T> operator*(Vec<N,T> x, Vec<N,T> y) { return map(x,y, std::multiplies<T>{}); }
+ ___ Vec<N,T> operator/(Vec<N,T> x, Vec<N,T> y) { return map(x,y, std::divides <T>{}); }
+
+ ___ Vec<N,T> operator^(Vec<N,T> x, Vec<N,T> y) { return map(x,y, std::bit_xor<T>{}); }
+ ___ Vec<N,T> operator&(Vec<N,T> x, Vec<N,T> y) { return map(x,y, std::bit_and<T>{}); }
+ ___ Vec<N,T> operator|(Vec<N,T> x, Vec<N,T> y) { return map(x,y, std::bit_or <T>{}); }
+
+ ___ Vec<N,T> operator!(Vec<N,T> x) { return map(x, std::logical_not<T>{}); }
+ ___ Vec<N,T> operator-(Vec<N,T> x) { return map(x, std::negate <T>{}); }
+ ___ Vec<N,T> operator~(Vec<N,T> x) { return map(x, std::bit_not <T>{}); }
+
+ ___ Vec<N,T> operator<<(Vec<N,T> x, int bits) { return map(x, [bits](T a) { return a << bits; }); }
+ ___ Vec<N,T> operator>>(Vec<N,T> x, int bits) { return map(x, [bits](T a) { return a >> bits; }); }
+
+ ___ Vec<N, mask<T>> operator==(Vec<N,T> x, Vec<N,T> y) { return map(x,y, [](T a, T b) -> mask<T> { return a == b ? ~0 : 0; }); }
+ ___ Vec<N, mask<T>> operator!=(Vec<N,T> x, Vec<N,T> y) { return map(x,y, [](T a, T b) -> mask<T> { return a != b ? ~0 : 0; }); }
+ ___ Vec<N, mask<T>> operator<=(Vec<N,T> x, Vec<N,T> y) { return map(x,y, [](T a, T b) -> mask<T> { return a <= b ? ~0 : 0; }); }
+ ___ Vec<N, mask<T>> operator>=(Vec<N,T> x, Vec<N,T> y) { return map(x,y, [](T a, T b) -> mask<T> { return a >= b ? ~0 : 0; }); }
+ ___ Vec<N, mask<T>> operator< (Vec<N,T> x, Vec<N,T> y) { return map(x,y, [](T a, T b) -> mask<T> { return a < b ? ~0 : 0; }); }
+ ___ Vec<N, mask<T>> operator> (Vec<N,T> x, Vec<N,T> y) { return map(x,y, [](T a, T b) -> mask<T> { return a > b ? ~0 : 0; }); }
+#endif
+
+// Some operations we want are not expressible with Clang/GCC vector extensions,
+// so we implement them using the same approach as the alternate path above.
+
+___ Vec<N,T> if_then_else(Vec<N,mask<T>> cond, Vec<N,T> t, Vec<N,T> e) {
+ Vec<N,mask<T>> t_bits = bit_pun(t),
+ e_bits = bit_pun(e);
+ return bit_pun( (cond & t_bits) | (~cond & e_bits) );
+}
+
+___ Vec<N,T> min(Vec<N,T> x, Vec<N,T> y) { return map(x,y, [](T a, T b) { return std::min(a,b); }); }
+___ Vec<N,T> max(Vec<N,T> x, Vec<N,T> y) { return map(x,y, [](T a, T b) { return std::max(a,b); }); }
+
+___ T min(Vec<N,T> x) { return *std::min_element(x.vals, x.vals+N); }
+___ T max(Vec<N,T> x) { return *std::max_element(x.vals, x.vals+N); }
+
+___ bool any(Vec<N,T> x) { return std::any_of(x.vals, x.vals+N, [](T a) { return a != mask<T>(0); }); }
+___ bool all(Vec<N,T> x) { return std::all_of(x.vals, x.vals+N, [](T a) { return a != mask<T>(0); }); }
+
+// Platform-specific specializations and overloads can now drop in here.
+
+} // namespace skvx
+
+#undef ALWAYS_INLINE
+#undef ___
+
+#endif//SKVX_DEFINED
diff --git a/tests/SkVxTest.cpp b/tests/SkVxTest.cpp
new file mode 100644
index 0000000..71290ad
--- /dev/null
+++ b/tests/SkVxTest.cpp
@@ -0,0 +1,79 @@
+/*
+ * Copyright 2019 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkVx.h"
+#include "Test.h"
+
+using float2 = skvx::Vec<2,float>;
+using float4 = skvx::Vec<4,float>;
+using float8 = skvx::Vec<8,float>;
+
+using double2 = skvx::Vec<2,double>;
+using double4 = skvx::Vec<4,double>;
+using double8 = skvx::Vec<8,double>;
+
+using byte2 = skvx::Vec<2,uint8_t>;
+using byte4 = skvx::Vec<4,uint8_t>;
+using byte8 = skvx::Vec<8,uint8_t>;
+
+using int2 = skvx::Vec<2,int32_t>;
+using int4 = skvx::Vec<4,int32_t>;
+using int8 = skvx::Vec<8,int32_t>;
+
+using long2 = skvx::Vec<2,int64_t>;
+using long4 = skvx::Vec<4,int64_t>;
+using long8 = skvx::Vec<8,int64_t>;
+
+DEF_TEST(SkVx, r) {
+ static_assert(sizeof(float2) == 8, "");
+ static_assert(sizeof(float4) == 16, "");
+ static_assert(sizeof(float8) == 32, "");
+
+ static_assert(sizeof(byte2) == 2, "");
+ static_assert(sizeof(byte4) == 4, "");
+ static_assert(sizeof(byte8) == 8, "");
+
+ {
+ int4 mask = float4{1,2,3,4} < float4{1,2,4,8};
+ REPORTER_ASSERT(r, mask[0] == int32_t( 0));
+ REPORTER_ASSERT(r, mask[1] == int32_t( 0));
+ REPORTER_ASSERT(r, mask[2] == int32_t(-1));
+ REPORTER_ASSERT(r, mask[3] == int32_t(-1));
+
+ REPORTER_ASSERT(r, any(mask));
+ REPORTER_ASSERT(r, !all(mask));
+ }
+
+ {
+ long4 mask = double4{1,2,3,4} < double4{1,2,4,8};
+ REPORTER_ASSERT(r, mask[0] == int64_t( 0));
+ REPORTER_ASSERT(r, mask[1] == int64_t( 0));
+ REPORTER_ASSERT(r, mask[2] == int64_t(-1));
+ REPORTER_ASSERT(r, mask[3] == int64_t(-1));
+
+ REPORTER_ASSERT(r, any(mask));
+ REPORTER_ASSERT(r, !all(mask));
+ }
+
+ REPORTER_ASSERT(r, min(float4{1,2,3,4}) == 1);
+ REPORTER_ASSERT(r, max(float4{1,2,3,4}) == 4);
+
+ REPORTER_ASSERT(r, all(int4{1,2,3,4,5} == int4{1,2,3,4}));
+ REPORTER_ASSERT(r, all(int4{1,2,3,4} == int4{1,2,3,4}));
+ REPORTER_ASSERT(r, all(int4{1,2,3} == int4{1,2,3,0}));
+ REPORTER_ASSERT(r, all(int4{1,2} == int4{1,2,0,0}));
+ REPORTER_ASSERT(r, all(int4{1} == int4{1,0,0,0}));
+ REPORTER_ASSERT(r, all(int4(1) == int4{1,1,1,1}));
+ REPORTER_ASSERT(r, all(int4{} == int4{0,0,0,0}));
+ REPORTER_ASSERT(r, all(int4() == int4{0,0,0,0}));
+
+ REPORTER_ASSERT(r, all(int4{1,2,2,1} == min(int4{1,2,3,4}, int4{4,3,2,1})));
+ REPORTER_ASSERT(r, all(int4{4,3,3,4} == max(int4{1,2,3,4}, int4{4,3,2,1})));
+
+ REPORTER_ASSERT(r, all(if_then_else(float4{1,2,3,2} <= float4{2,2,2,2}, float4(42), float4(47))
+ == float4{42,42,47,42}));
+}
