Add padding back to make msan happy

SkGlyph are stored directly in the hash table with uninitialized
pad bytes. When the hash table is resized, the uninitialized pad
bytes are moved causing msan to complain.

Change-Id: I559ff1bd369d12be061cce7d3c826c2afdd3a03c
Reviewed-on: https://skia-review.googlesource.com/125240
Commit-Queue: Herb Derby <herb@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
Auto-Submit: Herb Derby <herb@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/core/SkGlyph.h b/src/core/SkGlyph.h
index 87cd852bd8..959f9b78c8 100644
--- a/src/core/SkGlyph.h
+++ b/src/core/SkGlyph.h
@@ -131,6 +131,10 @@ struct SkPackedUnicharID : public SkPackedID {
     }
 };
 
+// Because SkGlyph is used directly in a hash table, it can be moved around using memcpy, and any
+// uninitialized pad bytes will be considered uninitialized. Make sure all pad bytes have an
+// initialized value.
+SK_BEGIN_REQUIRE_DENSE
 class SkGlyph {
     // Support horizontal and vertical skipping strike-through / underlines.
     // The caller walks the linked list looking for a match. For a horizontal underline,
@@ -160,6 +164,9 @@ public:
     uint8_t     fMaskFormat;
 #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
     int8_t      fRsbDelta, fLsbDelta;  // used by auto-kerning
+#else
+    int8_t      pad0{0}, pad1{0}; // It's simplest to add pads here. This will all change once
+                                  // we rip androids hand out of this data structure.
 #endif
     int8_t      fForceBW;
 
@@ -225,5 +232,6 @@ public:
 #endif
     SkPackedGlyphID fID;
 };
+SK_END_REQUIRE_DENSE
 
 #endif