commit 05a3eac35c58295caf5937da42c32da540b05cb0
author cblume <cblume@chromium.org> Mon Sep 19 21:05:18 2016 -0700
committer Commit bot <commit-bot@chromium.org> Mon Sep 19 21:05:18 2016 -0700
tree 023564e7babe5d9a8221431a0e48e5153e0114c1
parent 4562f6ecda4dd819561e3eee17defd525017b3e1

SkASSERT firing because pointer wraps negative.

Some pointers are being cast to intptr_t so they can be used with
SkAlign8(). However, a large pointer value might become a negative
integer since intptr_t is signed.

When comparing these intptr_ts, we expect the larger pointer value to be
greater. But it might be so large that it becomes negative, causing it
to be less than.

A SkASSERT is firing for this exact reason.

BUG=648452
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2353453004

Review-Url: https://codereview.chromium.org/2353453004

src/image/SkImage_Gpu.cpp

diff --git a/src/image/SkImage_Gpu.cpp b/src/image/SkImage_Gpu.cpp
index 55fb47a..f8e3b94 100644
--- a/src/image/SkImage_Gpu.cpp
+++ b/src/image/SkImage_Gpu.cpp
@@ -409,7 +409,7 @@
 class DTIBufferFiller
 {
 public:
-    explicit DTIBufferFiller(intptr_t bufferAsInt)
+    explicit DTIBufferFiller(uintptr_t bufferAsInt)
         : bufferAsInt_(bufferAsInt) {}
 
     void fillMember(const void* source, size_t memberOffset, size_t size) {
@@ -418,7 +418,7 @@
 
 private:
 
-    intptr_t bufferAsInt_;
+    uintptr_t bufferAsInt_;
 };
 }
 
@@ -552,8 +552,8 @@
     if (!fillMode) {
         return size;
     }
-    intptr_t bufferAsInt = reinterpret_cast<intptr_t>(buffer);
-    intptr_t pixelsAsInt = bufferAsInt + pixelOffset;
+    uintptr_t bufferAsInt = reinterpret_cast<uintptr_t>(buffer);
+    uintptr_t pixelsAsInt = bufferAsInt + pixelOffset;
     void* pixels = reinterpret_cast<void*>(pixelsAsInt);
     void* ct = nullptr;
     if (ctSize) {
@@ -604,7 +604,7 @@
     }
 
     // Fill in the mipmap levels if they exist
-    intptr_t mipLevelPtr = pixelsAsInt + SkAlign8(pixmap.getSafeSize());
+    uintptr_t mipLevelPtr = pixelsAsInt + SkAlign8(pixmap.getSafeSize());
 
     if (useMipMaps) {
         static_assert(std::is_standard_layout<MipMapLevelData>::value,