commit c6c2a8aff3f35c665bd78e716f2c5d2026ef02e9
author Ivan Lozano <ivanlozano@google.com> Mon Oct 30 11:24:08 2017 -0700
committer Ivan Lozano <ivanlozano@google.com> Wed Dec 20 15:03:11 2017 -0800
tree bace6901df623aadf358906feccc4aaa2680c7ef
parent a9c7e6d15201dbb701dc1f535689910a581912b0

Fix surfaceflinger on integer sanitized builds.

Refactors unsigned integer overflows in do_compare to fix integer
overflow sanitized builds. Also disables sanitization in
Layer::makeTraversalList.

Test: Compiled and checked output from sanitizer.
Bug: 30969751
Change-Id: I1a6d73435495e8b3ba3edb2587f62e4a0f2662f3
Merged-In: I1a6d73435495e8b3ba3edb2587f62e4a0f2662f3

services/surfaceflinger/LayerVector.cpp

diff --git a/services/surfaceflinger/LayerVector.cpp b/services/surfaceflinger/LayerVector.cpp
index 2233e78..d0f8fbe 100644
--- a/services/surfaceflinger/LayerVector.cpp
+++ b/services/surfaceflinger/LayerVector.cpp
@@ -35,14 +35,17 @@
     uint32_t ls = l->getCurrentState().layerStack;
     uint32_t rs = r->getCurrentState().layerStack;
     if (ls != rs)
-        return ls - rs;
+        return (ls > rs) ? 1 : -1;
 
     uint32_t lz = l->getCurrentState().z;
     uint32_t rz = r->getCurrentState().z;
     if (lz != rz)
-        return lz - rz;
+        return (lz > rz) ? 1 : -1;
 
-    return l->sequence - r->sequence;
+    if (l->sequence == r->sequence)
+        return 0;
+
+    return (l->sequence > r->sequence) ? 1 : -1;
 }
 
 void LayerVector::traverseInZOrder(StateSet stateSet, const Visitor& visitor) const {