SkNx_abi for passing Sk4f as function arguments, etc.

CQ_INCLUDE_TRYBOTS=master.client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot,Test-Ubuntu-Clang-GCE-CPU-AVX2-x86_64-Debug-ASAN-Trybot

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3422

Change-Id: Idc0a192faa7ff843aef023229186580c69baf1f7
Reviewed-on: https://skia-review.googlesource.com/3422
Reviewed-by: Mike Klein <mtklein@chromium.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/core/SkNx.h b/src/core/SkNx.h
index afba75a487..6d9af9fe47 100644
--- a/src/core/SkNx.h
+++ b/src/core/SkNx.h
@@ -16,6 +16,11 @@
 #include <math.h>
 #include <type_traits>
 
+// These _abi types are data-only, and so can be used to store SkNx in structs or
+// pass them as function parameters or return values, even across compilation units.
+template <int N, typename T> struct SkNx_abi      { SkNx_abi<N/2,T> lo, hi; };
+template <       typename T> struct SkNx_abi<1,T> {              T     val; };
+
 namespace {
 
 #define SI static inline
@@ -42,6 +47,9 @@ struct SkNx {
         static_assert(N==16, "");
     }
 
+    SkNx(const SkNx_abi<N,T>& a) : fLo(a.lo), fHi(a.hi) {}
+    operator SkNx_abi<N,T>() const { return { (SkNx_abi<N/2,T>)fLo, (SkNx_abi<N/2,T>)fHi }; }
+
     T operator[](int k) const {
         SkASSERT(0 <= k && k < N);
         return k < N/2 ? fLo[k] : fHi[k-N/2];
@@ -129,6 +137,9 @@ struct SkNx<1,T> {
     SkNx() = default;
     SkNx(T v) : fVal(v) {}
 
+    SkNx(const SkNx_abi<1,T>& a) : fVal(a.val) {}
+    operator SkNx_abi<1,T>() const { return { fVal }; }
+
     // Android complains against unused parameters, so we guard it
     T operator[](int SkDEBUGCODE(k)) const {
         SkASSERT(k == 0);