Running automated tests with fsanitize=enum produces errors like: > [task 2017-09-25T00:47:27.425Z] 00:47:27 INFO - REFTEST INFO | RESTORE PREFERENCE pref(layout.css.servo.enabled,true) > [task 2017-09-25T00:47:27.427Z] 00:47:27 INFO - REFTEST TEST-LOAD | file:///builds/worker/workspace/build/tests/reftest/tests/layout/reftests/w3c-css/submitted/masking/clip-path-mix-blend-mode-1.html | 1524 / 1937 (78%) > [task 2017-09-25T00:47:27.467Z] 00:47:27 INFO - /builds/worker/workspace/build/src/gfx/skia/skia/src/core/SkXfermode_proccoeff.h:29:25: runtime error: load of value 4294967295, which is not a valid value for type 'Coeff' > [task 2017-09-25T00:47:27.468Z] 00:47:27 INFO - /builds/worker/workspace/build/src/gfx/skia/skia/src/core/SkXfermode_proccoeff.h:30:25: runtime error: load of value 4294967295, which is not a valid value for type 'Coeff' Probably this will need to be fixed upstream?

Here's an example stack trace: [task 2017-10-03T08:48:10.653Z] 08:48:10 INFO - REFTEST TEST-LOAD | file:///builds/worker/workspace/build/tests/reftest/tests/layout/reftests/async-scrolling/offscreen-clipped-blendmode-2.html | 1442 / 1953 (73%) -10-03T08:48:10.687Z] 08:48:10 INFO - /builds/worker/workspace/build/src/gfx/skia/skia/src/core/SkXfermode_proccoeff.h:29:25: runtime error: load of value 4294967295, which is not a valid value for type 'Coeff' [task 2017-10-03T08:48:10.688Z] 08:48:10 INFO - #0 0xf25800d1 in SkProcCoeffXfermode::SkProcCoeffXfermode(ProcCoeff const&, SkBlendMode) (/builds/worker/workspace/build/application/firefox/libxul.so+0x32850d1) [task 2017-10-03T08:48:10.689Z] 08:48:10 INFO - #1 0xf263da3e in ssse3::create_xfermode(ProcCoeff const&, SkBlendMode) (/builds/worker/workspace/build/application/firefox/libxul.so+0x3342a3e) [task 2017-10-03T08:48:10.691Z] 08:48:10 INFO - #2 0xf2596fdd in SkXfermode::Make(SkBlendMode) (/builds/worker/workspace/build/application/firefox/libxul.so+0x329bfdd) [task 2017-10-03T08:48:10.691Z] 08:48:10 INFO - #3 0xf258ce6d in SkSpriteBlitter::ChooseL32(SkPixmap const&, SkPaint const&, SkArenaAlloc*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x3291e6d) [task 2017-10-03T08:48:10.693Z] 08:48:10 INFO - #4 0xf2527c0d in SkBlitter::ChooseSprite(SkPixmap const&, SkPaint const&, SkPixmap const&, int, int, SkArenaAlloc*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x322cc0d) [task 2017-10-03T08:48:10.693Z] 08:48:10 INFO - #5 0xf2756a83 in SkDraw::drawBitmap(SkBitmap const&, SkMatrix const&, SkRect const*, SkPaint const&) const (/builds/worker/workspace/build/application/firefox/libxul.so+0x345ba83) [task 2017-10-03T08:48:10.694Z] 08:48:10 INFO - #6 0xf264d1b6 in SkBitmapDevice::drawBitmapRect(SkBitmap const&, SkRect const*, SkRect const&, SkPaint const&, SkCanvas::SrcRectConstraint) (/builds/worker/workspace/build/application/firefox/libxul.so+0x33521b6) [task 2017-10-03T08:48:10.695Z] 08:48:10 INFO - #7 0xf27479a4 in SkBaseDevice::drawImageRect(SkImage const*, SkRect const*, SkRect const&, SkPaint const&, SkCanvas::SrcRectConstraint) (/builds/worker/workspace/build/application/firefox/libxul.so+0x344c9a4) [task 2017-10-03T08:48:10.695Z] 08:48:10 INFO - #8 0xf2665bc6 in SkCanvas::onDrawImageRect(SkImage const*, SkRect const*, SkRect const&, SkPaint const*, SkCanvas::SrcRectConstraint) (/builds/worker/workspace/build/application/firefox/libxul.so+0x336abc6) [task 2017-10-03T08:48:10.703Z] 08:48:10 INFO - #9 0xf02c0ded in mozilla::gfx::DrawTargetSkia::DrawSurface(mozilla::gfx::SourceSurface*, mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float> const&, mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float> const&, mozilla::gfx::DrawSurfaceOptions const&, mozilla::gfx::DrawOptions const&) (/builds/worker/workspace/build/application/firefox/libxul.so+0xfc5ded) [task 2017-10-03T08:48:10.708Z] 08:48:10 INFO - #10 0xf04a1707 in mozilla::layers::BasicLayerManager::PopGroupForLayer(mozilla::layers::BasicLayerManager::PushedGroup&) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11a6707) [task 2017-10-03T08:48:10.709Z] 08:48:10 INFO - #11 0xf04a6756 in mozilla::layers::BasicPaintedLayer::PaintThebes(gfxContext*, mozilla::layers::Layer*, void (*)(mozilla::layers::PaintedLayer*, gfxContext*, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::layers::DrawRegionClip, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, void*), void*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11ab756) [task 2017-10-03T08:48:10.711Z] 08:48:10 INFO - #12 0xf04a79ab in mozilla::layers::BasicLayerManager::PaintSelfOrChildren(mozilla::layers::PaintLayerContext&, gfxContext*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11ac9ab) [task 2017-10-03T08:48:10.712Z] 08:48:10 INFO - #13 0xf04a6fe0 in mozilla::layers::BasicLayerManager::PaintLayer(gfxContext*, mozilla::layers::Layer*, void (*)(mozilla::layers::PaintedLayer*, gfxContext*, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::layers::DrawRegionClip, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, void*), void*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11abfe0) [task 2017-10-03T08:48:10.713Z] 08:48:10 INFO - #14 0xf04a7855 in mozilla::layers::BasicLayerManager::PaintSelfOrChildren(mozilla::layers::PaintLayerContext&, gfxContext*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11ac855) [task 2017-10-03T08:48:10.716Z] 08:48:10 INFO - #15 0xf04a6fe0 in mozilla::layers::BasicLayerManager::PaintLayer(gfxContext*, mozilla::layers::Layer*, void (*)(mozilla::layers::PaintedLayer*, gfxContext*, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::layers::DrawRegionClip, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, void*), void*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11abfe0) [task 2017-10-03T08:48:10.718Z] 08:48:10 INFO - #16 0xf04a7855 in mozilla::layers::BasicLayerManager::PaintSelfOrChildren(mozilla::layers::PaintLayerContext&, gfxContext*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11ac855) [task 2017-10-03T08:48:10.719Z] 08:48:10 INFO - #17 0xf04a772b in mozilla::layers::BasicLayerManager::PaintLayer(gfxContext*, mozilla::layers::Layer*, void (*)(mozilla::layers::PaintedLayer*, gfxContext*, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::layers::DrawRegionClip, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, void*), void*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11ac72b) [task 2017-10-03T08:48:10.720Z] 08:48:10 INFO - #18 0xf04a7855 in mozilla::layers::BasicLayerManager::PaintSelfOrChildren(mozilla::layers::PaintLayerContext&, gfxContext*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11ac855) [task 2017-10-03T08:48:10.721Z] 08:48:10 INFO - #19 0xf04a6fe0 in mozilla::layers::BasicLayerManager::PaintLayer(gfxContext*, mozilla::layers::Layer*, void (*)(mozilla::layers::PaintedLayer*, gfxContext*, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::layers::DrawRegionClip, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, void*), void*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11abfe0) [task 2017-10-03T08:48:10.723Z] 08:48:10 INFO - #20 0xf04a7d12 in mozilla::layers::BasicLayerManager::EndTransactionInternal(void (*)(mozilla::layers::PaintedLayer*, gfxContext*, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::layers::DrawRegionClip, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, void*), void*, mozilla::layers::LayerManager::EndTransactionFlags) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11acd12) [task 2017-10-03T08:48:10.724Z] 08:48:10 INFO - #21 0xf1eba2f6 in mozilla::FrameLayerBuilder::PaintItems(nsTArray<mozilla::FrameLayerBuilder::ClippedDisplayItem>&, mozilla::gfx::IntRectTyped<mozilla::gfx::UnknownUnits> const&, gfxContext*, nsDisplayListBuilder*, nsPresContext*, mozilla::gfx::IntPointTyped<mozilla::gfx::UnknownUnits> const&, float, float, int) (/builds/worker/workspace/build/application/firefox/libxul.so+0x2bbf2f6) [task 2017-10-03T08:48:10.726Z] 08:48:10 INFO - #22 0xf1ebb143 in mozilla::FrameLayerBuilder::DrawPaintedLayer(mozilla::layers::PaintedLayer*, gfxContext*, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::layers::DrawRegionClip, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, void*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x2bc0143) [task 2017-10-03T08:48:10.733Z] 08:48:10 INFO - #23 0xf04b542c in mozilla::layers::ClientPaintedLayer::PaintThebes(nsTArray<mozilla::layers::ReadbackProcessor::Update>*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11ba42c) [task 2017-10-03T08:48:10.734Z] 08:48:10 INFO - #24 0xf04bc23f in mozilla::layers::ClientPaintedLayer::RenderLayerWithReadback(mozilla::layers::ReadbackProcessor*) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11c123f) [task 2017-10-03T08:48:10.735Z] 08:48:10 INFO - #25 0xf04b8a4f in mozilla::layers::ClientContainerLayer::RenderLayer() (/builds/worker/workspace/build/application/firefox/libxul.so+0x11bda4f) [task 2017-10-03T08:48:10.736Z] 08:48:10 INFO - #26 0xf04bdae2 in mozilla::layers::ClientLayerManager::EndTransactionInternal(void (*)(mozilla::layers::PaintedLayer*, gfxContext*, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::layers::DrawRegionClip, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, void*), void*, mozilla::layers::LayerManager::EndTransactionFlags) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11c2ae2) [task 2017-10-03T08:48:10.737Z] 08:48:10 INFO - #27 0xf04c4cff in mozilla::layers::ClientLayerManager::EndTransaction(void (*)(mozilla::layers::PaintedLayer*, gfxContext*, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, mozilla::layers::DrawRegionClip, mozilla::gfx::IntRegionTyped<mozilla::gfx::UnknownUnits> const&, void*), void*, mozilla::layers::LayerManager::EndTransactionFlags) (/builds/worker/workspace/build/application/firefox/libxul.so+0x11c9cff) [task 2017-10-03T08:48:10.738Z] 08:48:10 INFO - #28 0xf1ec3ab4 in nsDisplayList::PaintRoot(nsDisplayListBuilder*, gfxContext*, unsigned int) (/builds/worker/workspace/build/application/firefox/libxul.so+0x2bc8ab4) [task 2017-10-03T08:48:10.739Z] 08:48:10 INFO - #29 0xf1bf2f6e in nsLayoutUtils::PaintFrame(gfxContext*, nsIFrame*, nsRegion const&, unsigned int, nsDisplayListBuilderMode, nsLayoutUtils::PaintFrameFlags) (/builds/worker/workspace/build/application/firefox/libxul.so+0x28f7f6e) [task 2017-10-03T08:48:10.740Z] 08:48:10 INFO - #30 0xf1b87d15 in mozilla::PresShell::Paint(nsView*, nsRegion const&, unsigned int) (/builds/worker/workspace/build/application/firefox/libxul.so+0x288cd15) [task 2017-10-03T08:48:10.741Z] 08:48:10 INFO - #31 0xf06b3634 in nsDOMWindowUtils::UpdateLayerTree() (/builds/worker/workspace/build/application/firefox/libxul.so+0x13b8634) [task 2017-10-03T08:48:10.742Z] 08:48:10 INFO - #32 0xef78a1a9 in NS_InvokeByIndex (/builds/worker/workspace/build/application/firefox/libxul.so+0x48f1a9) [task 2017