Fix sign problem, implement low-mem mmap wraparound

A signed value comparison meant that on 64b systems comparisons
were false when pointers > 2GB were in use (as happens in long-running
tests). Fix this to be uint.

Implement a simple wrap-around in the MAP_32BIT emulation code.

Change-Id: I09870b4755f2dca676e42e701fbb6f6eb4bb95d0

1 files changed, 3 insertions, 2 deletions

diff --git a/runtime/interpreter/interpreter_common.cc b/runtime/interpreter/interpreter_common.cc
index e8cea9d..297f1a8 100644
--- a/runtime/interpreter/interpreter_common.cc
+++ b/runtime/interpreter/interpreter_common.cc
@@ -30,9 +30,10 @@ static inline void AssignRegister(ShadowFrame* new_shadow_frame, const ShadowFra
                                   size_t dest_reg, size_t src_reg)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   // If both register locations contains the same value, the register probably holds a reference.
-  int32_t src_value = shadow_frame.GetVReg(src_reg);
+  // Uint required, so that sign extension does not make this wrong on 64b systems
+  uint32_t src_value = shadow_frame.GetVReg(src_reg);
   mirror::Object* o = shadow_frame.GetVRegReference<kVerifyNone>(src_reg);
-  if (src_value == reinterpret_cast<intptr_t>(o)) {
+  if (src_value == reinterpret_cast<uintptr_t>(o)) {
     new_shadow_frame->SetVRegReference(dest_reg, o);
   } else {
     new_shadow_frame->SetVReg(dest_reg, src_value);