Bug 1443342 - Don't blacklist nsCSSProps.cpp:SortPropertyAndCount from integer-overflow sanitizing. r=froydnj

--HG--
extra : rebase_source : b5d9da242923e0ae43abf6a508e0298b64741466

build/sanitizers/ubsan_signed_overflow_blacklist.txt

@@ -149,10 +149,6 @@ fun:*OT*collect_glyphs*
 # These look like harmless layouting-related overflows
 src:*/gfx/cairo/libpixman/src/pixman-region.c
 
-# Sorting code in layout/style/nsCSSProps.cpp that probably doesn't
-# care about overflows.
-fun:*SortPropertyAndCount*
-
 # Code in ipc/chromium/src/base/file_path.cc where a function returns -1
 # being cast to unsigned and then overflowed.
 fun:*FilePath*Append*

build/sanitizers/ubsan_unsigned_overflow_blacklist.txt

@@ -156,10 +156,6 @@ fun:*OT*collect_glyphs*
 # These look like harmless layouting-related overflows
 src:*/gfx/cairo/libpixman/src/pixman-region.c
 
-# Sorting code in layout/style/nsCSSProps.cpp that probably doesn't
-# care about overflows.
-fun:*SortPropertyAndCount*
-
 # Code in ipc/chromium/src/base/file_path.cc where a function returns -1
 # being cast to unsigned and then overflowed.
 fun:*FilePath*Append*

layout/style/nsCSSProps.cpp

@@ -12,6 +12,7 @@
 #include "nsCSSProps.h"
 
 #include "mozilla/ArrayUtils.h"
+#include "mozilla/Casting.h"
 
 #include "nsCSSKeywords.h"
 #include "nsLayoutUtils.h"
@@ -140,9 +141,13 @@ SortPropertyAndCount(const void* s1, const void* s2, void *closure)
 {
   const PropertyAndCount *pc1 = static_cast<const PropertyAndCount*>(s1);
   const PropertyAndCount *pc2 = static_cast<const PropertyAndCount*>(s2);
+
   // Primary sort by count (lowest to highest)
-  if (pc1->count != pc2->count)
-    return pc1->count - pc2->count;
+  if (pc1->count != pc2->count) {
+    return AssertedCast<int32_t>(pc1->count) -
+           AssertedCast<int32_t>(pc2->count);
+  }
+
   // Secondary sort by property index (highest to lowest)
   return pc2->property - pc1->property;
 }