commit a0c4c3407d57296eb914cd1c6e0f588f86fe8404
author Mike Klein <mtklein@chromium.org> Tue Nov 29 13:58:49 2016 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Tue Nov 29 19:56:49 2016 +0000
tree 8bbf81b2facc0180ba02de483743b9a05a573a26
parent 94efbf51f5a88d9e8aa961d3fbe38c5e335d6108

teach MSAN about maskload

There is a very telling FIXME in the MSAN source code:
    // FIXME: detect and handle SSE maskstore/maskload

For now, just tell MSAN (correctly) that it's initialized.

CQ_INCLUDE_TRYBOTS=skia.primary:Test-Ubuntu-Clang-GCE-CPU-AVX2-x86_64-Debug-MSAN,Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD


Change-Id: I6aec67b99e4d930cb72e438458b33ed116535009
Reviewed-on: https://skia-review.googlesource.com/5311
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Brian Osman <brianosman@google.com>

src/opts/SkRasterPipeline_opts.h

diff --git a/src/opts/SkRasterPipeline_opts.h b/src/opts/SkRasterPipeline_opts.h
index d38e0ca..88a872c 100644
--- a/src/opts/SkRasterPipeline_opts.h
+++ b/src/opts/SkRasterPipeline_opts.h
@@ -14,6 +14,7 @@
 #include "SkColorSpaceXformPriv.h"
 #include "SkHalf.h"
 #include "SkImageShaderContext.h"
+#include "SkMSAN.h"
 #include "SkPM4f.h"
 #include "SkPM4fPriv.h"
 #include "SkRasterPipeline.h"
@@ -193,13 +194,22 @@
         return _mm256_mask_i32gather_epi32(SkNi(0).fVec,
                                            (const int*)src, offset.fVec, mask(tail), 4);
     }
+
+    static const char* bug = "I don't think MSAN understands maskstore.";
+
     SI void store(size_t tail, const SkNi& v,  int32_t* dst) {
-        tail ? _mm256_maskstore_epi32((int*)dst, mask(tail), v.fVec)
-             : v.store(dst);
+        if (tail) {
+            _mm256_maskstore_epi32((int*)dst, mask(tail), v.fVec);
+            return sk_msan_mark_initialized(dst, dst+tail, bug);
+        }
+        v.store(dst);
     }
     SI void store(size_t tail, const SkNu& v, uint32_t* dst) {
-        tail ? _mm256_maskstore_epi32((int*)dst, mask(tail), v.fVec)
-             : v.store(dst);
+        if (tail) {
+            _mm256_maskstore_epi32((int*)dst, mask(tail), v.fVec);
+            return sk_msan_mark_initialized(dst, dst+tail, bug);
+        }
+        v.store(dst);
     }
 #endif