Avoid SkFixed overflow in decal bitmap procs

The check for decal mode can overflow in SkFixed.  Promote to
64bit (48.16) instead.

Also update can_truncate_to_fixed_for_decal() to take SkFixed params and
used it in ClampX_ClampY_filter_scale_SSE2().

BUG=chromium:675444
R=reed@google.com

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

Change-Id: I759464cdaa5c005159e38e32167fb1937e2a1d28
Reviewed-on: https://skia-review.googlesource.com/6538
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>

1 files changed, 25 insertions, 20 deletions

diff --git a/src/core/SkBitmapProcState_matrix_template.h b/src/core/SkBitmapProcState_matrix_template.h
index 0c9371851c..c38610a077 100644
--- a/src/core/SkBitmapProcState_matrix_template.h
+++ b/src/core/SkBitmapProcState_matrix_template.h
@@ -36,32 +36,37 @@ void NoFilterProc_Scale(const SkBitmapProcState& s, uint32_t xy[],
 
     const SkFractionalInt dx = s.fInvSxFractionalInt;
 
-    if (tryDecal && can_truncate_to_fixed_for_decal(fx, dx, count, maxX)) {
-        decal_nofilter_scale(xy, SkFractionalIntToFixed(fx),
-                             SkFractionalIntToFixed(dx), count);
-    } else {
-        int i;
-        for (i = (count >> 2); i > 0; --i) {
-            unsigned a, b;
-            a = TileProc::X(s, SkFractionalIntToFixed(fx), maxX); fx += dx;
-            b = TileProc::X(s, SkFractionalIntToFixed(fx), maxX); fx += dx;
+    if (tryDecal) {
+        const SkFixed fixedFx = SkFractionalIntToFixed(fx);
+        const SkFixed fixedDx = SkFractionalIntToFixed(dx);
+
+        if (can_truncate_to_fixed_for_decal(fixedFx, fixedDx, count, maxX)) {
+            decal_nofilter_scale(xy, fixedFx, fixedDx, count);
+            return;
+        }
+    }
+
+    int i;
+    for (i = (count >> 2); i > 0; --i) {
+        unsigned a, b;
+        a = TileProc::X(s, SkFractionalIntToFixed(fx), maxX); fx += dx;
+        b = TileProc::X(s, SkFractionalIntToFixed(fx), maxX); fx += dx;
 #ifdef SK_CPU_BENDIAN
-            *xy++ = (a << 16) | b;
+        *xy++ = (a << 16) | b;
 #else
-            *xy++ = (b << 16) | a;
+        *xy++ = (b << 16) | a;
 #endif
-            a = TileProc::X(s, SkFractionalIntToFixed(fx), maxX); fx += dx;
-            b = TileProc::X(s, SkFractionalIntToFixed(fx), maxX); fx += dx;
+        a = TileProc::X(s, SkFractionalIntToFixed(fx), maxX); fx += dx;
+        b = TileProc::X(s, SkFractionalIntToFixed(fx), maxX); fx += dx;
 #ifdef SK_CPU_BENDIAN
-            *xy++ = (a << 16) | b;
+        *xy++ = (a << 16) | b;
 #else
-            *xy++ = (b << 16) | a;
+        *xy++ = (b << 16) | a;
 #endif
-        }
-        uint16_t* xx = (uint16_t*)xy;
-        for (i = (count & 3); i > 0; --i) {
-            *xx++ = TileProc::X(s, SkFractionalIntToFixed(fx), maxX); fx += dx;
-        }
+    }
+    uint16_t* xx = (uint16_t*)xy;
+    for (i = (count & 3); i > 0; --i) {
+        *xx++ = TileProc::X(s, SkFractionalIntToFixed(fx), maxX); fx += dx;
     }
 }