# HG changeset patch
# Parent  548d0a2f3a22bfac32ec0c3921c6c969c8bf32a9
Skia does not support big endian. The places to fix are too numerous and upstream (skia, not Mozilla)
has no interest in maintaining big endian.
So here we try to swizzle the input for skia, so that skia always works on LE, and when it comes
out again, we transform back to BE.

diff -r 548d0a2f3a22 gfx/2d/ConvolutionFilter.cpp
--- a/gfx/2d/ConvolutionFilter.cpp	Mon Jul 22 16:57:54 2019 +0200
+++ b/gfx/2d/ConvolutionFilter.cpp	Thu Jul 25 14:27:59 2019 +0200
@@ -35,9 +35,38 @@
   return true;
 }
 
+static void ByteSwapArray(uint8_t *u8Array, int32_t size) {
+    uint32_t *array = reinterpret_cast<uint32_t*>(u8Array);
+    for (int pxl = 0; pxl < size; ++pxl) {
+        // Use an endian swap to move the bytes, i.e. BGRA -> ARGB.
+        uint32_t rgba = array[pxl];
+        array[pxl] = NativeEndian::swapToLittleEndian(rgba);
+    }
+}
+
 void ConvolutionFilter::ConvolveHorizontally(const uint8_t* aSrc, uint8_t* aDst,
                                              bool aHasAlpha) {
+#ifdef MOZ_BIG_ENDIAN
+    int outputSize = mFilter->numValues();
+
+    // Input size isn't handed in, so we have to calculate it quickly
+    int inputSize = 0;
+    for (int xx = 0; xx < outputSize; ++xx) {
+        // Get the filter that determines the current output pixel.
+        int filterOffset, filterLength;
+        mFilter->FilterForValue(xx, &filterOffset, &filterLength);
+        inputSize = std::max(inputSize, filterOffset + filterLength);
+    }
+
+    ByteSwapArray((uint8_t*)aSrc, inputSize);
+#endif
+
   SkOpts::convolve_horizontally(aSrc, *mFilter, aDst, aHasAlpha);
+
+#ifdef MOZ_BIG_ENDIAN
+    ByteSwapArray((uint8_t*)aSrc, inputSize);
+    ByteSwapArray(aDst, outputSize);
+#endif
 }
 
 void ConvolutionFilter::ConvolveVertically(uint8_t* const* aSrc, uint8_t* aDst,
@@ -49,8 +78,26 @@
   int32_t filterLength;
   auto filterValues =
       mFilter->FilterForValue(aRowIndex, &filterOffset, &filterLength);
+
+#ifdef MOZ_BIG_ENDIAN
+  for (int filterY = 0; filterY < filterLength; filterY++) {
+      // Skia only knows LE, so we have to swizzle the input
+    ByteSwapArray(aSrc[filterY], aRowSize);
+  }
+#endif
+
   SkOpts::convolve_vertically(filterValues, filterLength, aSrc, aRowSize, aDst,
                               aHasAlpha);
+
+#ifdef MOZ_BIG_ENDIAN
+  // After skia is finished, we swizzle back to BE, in case
+  // the input is used again somewhere else
+  for (int filterY = 0; filterY < filterLength; filterY++) {
+    ByteSwapArray(aSrc[filterY], aRowSize);
+  }
+  // The destination array as well
+  ByteSwapArray(aDst, aRowSize);
+#endif
 }
 
 /* ConvolutionFilter::ComputeResizeFactor is derived from Skia's
diff -r 548d0a2f3a22 gfx/skia/skia/include/core/SkPreConfig.h
--- a/gfx/skia/skia/include/core/SkPreConfig.h	Mon Jul 22 16:57:54 2019 +0200
+++ b/gfx/skia/skia/include/core/SkPreConfig.h	Thu Jul 25 14:27:59 2019 +0200
@@ -73,7 +73,7 @@
       defined(__ppc__) || defined(__hppa) || \
       defined(__PPC__) || defined(__PPC64__) || \
       defined(_MIPSEB) || defined(__ARMEB__) || \
-      defined(__s390__) || \
+      defined(__s390__) || defined(__s390x__) || \
       (defined(__sh__) && defined(__BIG_ENDIAN__)) || \
       (defined(__ia64) && defined(__BIG_ENDIAN__))
          #define SK_CPU_BENDIAN