Fix a DCHECK failure due to unmatching numbers of cards scanned.
- See the bug for details of the failure.
- After a discussion, we decided to get rid of the DCHECK as a simple
solution would not detect corner failure cases and a full solution
would add undesired complexity, and left a comment that explains
what situation had caused a DCHECK failure.
- Fix a potential error of failing to scan the last card that the end
of the image space falls on as a result of the image end being not
necessarily aligned by the card size.
- Remove dead/unused MarkSweep::ScanRoot().
- Add AlignUp and AlignDown for aligning pointers.
Bug: 11465268
Change-Id: Iee3018a42c48a159feb0e9cf77b1a6b303f5d245
diff --git a/runtime/utils.h b/runtime/utils.h
index 0174b37..51035b6 100644
--- a/runtime/utils.h
+++ b/runtime/utils.h
@@ -119,6 +119,7 @@
typedef B value;
};
+// For rounding integers.
template<typename T>
static inline T RoundDown(T x, int n) {
CHECK(IsPowerOfTwo(n));
@@ -130,6 +131,18 @@
return RoundDown(x + n - 1, n);
}
+// For aligning pointers.
+template<typename T>
+static inline T* AlignDown(T* x, int n) {
+ CHECK(IsPowerOfTwo(n));
+ return reinterpret_cast<T*>(reinterpret_cast<uintptr_t>(x) & -static_cast<uintptr_t>(n));
+}
+
+template<typename T>
+static inline T* AlignUp(T* x, int n) {
+ return AlignDown(reinterpret_cast<T*>(reinterpret_cast<uintptr_t>(x) + static_cast<uintptr_t>(n - 1)), n);
+}
+
// Implementation is from "Hacker's Delight" by Henry S. Warren, Jr.,
// figure 3-3, page 48, where the function is called clp2.
static inline uint32_t RoundUpToPowerOfTwo(uint32_t x) {