ubsan shift fixes

include/core/SkTypes.h

Index: include/core/SkTypes.h
diff --git a/include/core/SkTypes.h b/include/core/SkTypes.h
index 6c2e6361530ac9674da7f69f7b2dd978bb80ce32..77acbfded734821f3d599be8291d698c072e603f 100644
--- a/include/core/SkTypes.h
+++ b/include/core/SkTypes.h
@@ -303,6 +303,22 @@ static inline bool SkIsU16(long x) {
     return (uint16_t)x == x;
 }
 
+static inline int32_t SkLeftShift(int32_t value, int32_t shift) {
+#ifdef SK_BUILT_WITH_SANITIZER
+    return (int32_t) ((uint32_t) value << shift);

[reed1, 2015/12/09 15:54:26]

do we think we can't always use the version here (line 308)? Wonder if we need
the if/else

[mtklein, 2015/12/09 16:48:11]

agree... both'll generate the same code.

[caryclark, 2015/12/09 19:13:12]

Done.

+#else
+    return value << shift;
+#endif
+}
+
+static inline int64_t SkLeftShift(int64_t value, int32_t shift) {
+#ifdef SK_BUILT_WITH_SANITIZER
+    return (int64_t) ((uint64_t) value << shift);
+#else
+    return value << shift;
+#endif
+}
+
 //////////////////////////////////////////////////////////////////////////////
 
 /** Returns the number of entries in an array (not a pointer) */