Ensure MemoryRegion::Load & MemoryRegion::Store are word-aligned.
Change-Id: Ib19fb93abec4789a111dfd48fcac6065e2d3ec82
diff --git a/runtime/memory_region.h b/runtime/memory_region.h
index f867f6a..3dcb0dd 100644
--- a/runtime/memory_region.h
+++ b/runtime/memory_region.h
@@ -48,17 +48,20 @@
uint8_t* end() const { return start() + size_; }
// Load value of type `T` at `offset`. The memory address corresponding
- // to `offset` should be word-aligned.
+ // to `offset` should be word-aligned (on ARM, this is a requirement).
template<typename T> T Load(uintptr_t offset) const {
- // TODO: DCHECK that the address is word-aligned.
- return *ComputeInternalPointer<T>(offset);
+ T* address = ComputeInternalPointer<T>(offset);
+ DCHECK(IsWordAligned(address));
+ return *address;
}
// Store `value` (of type `T`) at `offset`. The memory address
- // corresponding to `offset` should be word-aligned.
+ // corresponding to `offset` should be word-aligned (on ARM, this is
+ // a requirement).
template<typename T> void Store(uintptr_t offset, T value) const {
- // TODO: DCHECK that the address is word-aligned.
- *ComputeInternalPointer<T>(offset) = value;
+ T* address = ComputeInternalPointer<T>(offset);
+ DCHECK(IsWordAligned(address));
+ *address = value;
}
// Load value of type `T` at `offset`. The memory address corresponding
@@ -141,6 +144,13 @@
return ComputeInternalPointer<uint8_t>(byte_offset);
}
+ // Is `address` aligned on a machine word?
+ template<typename T> static bool IsWordAligned(const T* address) {
+ // Word alignment in bytes.
+ size_t kWordAlignment = GetInstructionSetPointerSize(kRuntimeISA);
+ return IsAlignedParam(address, kWordAlignment);
+ }
+
void* pointer_;
size_t size_;
};
diff --git a/runtime/stack_map.h b/runtime/stack_map.h
index 6ec7cc8..2c6240a 100644
--- a/runtime/stack_map.h
+++ b/runtime/stack_map.h
@@ -28,9 +28,6 @@
// (signed) values.
static ssize_t constexpr kFrameSlotSize = 4;
-// Word alignment required on ARM, in bytes.
-static constexpr size_t kWordAlignment = 4;
-
// Size of Dex virtual registers.
static size_t constexpr kVRegSize = 4;