A64: Handle a few TODOs.

src/a64/simulator-a64.cc

Index: src/a64/simulator-a64.cc
diff --git a/src/a64/simulator-a64.cc b/src/a64/simulator-a64.cc
index c80266bea69cfb229e8c7b304e1f8ba356281abc..64307fae6241052f7b0956c70107b6d2a446361c 100644
--- a/src/a64/simulator-a64.cc
+++ b/src/a64/simulator-a64.cc
@@ -304,12 +304,14 @@ void Simulator::CorruptAllCallerSavedCPURegisters() {
 
 
 // Extending the stack by 2 * 64 bits is required for stack alignment purposes.
-// TODO(all): Insert a marker in the extra space allocated on the stack.
 uintptr_t Simulator::PushAddress(uintptr_t address) {
   ASSERT(sizeof(uintptr_t) < 2 * kXRegSize);
   intptr_t new_sp = sp() - 2 * kXRegSize;
+  uintptr_t* alignment_slot =
+    reinterpret_cast<uintptr_t*>(new_sp + kXRegSize);
+  memcpy(alignment_slot, &kSlotsZapValue, kPointerSize);
   uintptr_t* stack_slot = reinterpret_cast<uintptr_t*>(new_sp);
-  *stack_slot = address;
+  memcpy(stack_slot, &address, kPointerSize);
   set_sp(new_sp);
   return new_sp;
 }
@@ -442,12 +444,6 @@ void Simulator::RunFrom(Instruction* start) {
 }
 
 
-void Simulator::CheckStackAlignment() {
-  // TODO(aleram): The sp alignment check to perform depends on the processor
-  // state. Check the specifications for more details.
-}
-
-
 // When the generated code calls an external reference we need to catch that in
 // the simulator.  The external reference will be a function compiled for the
 // host architecture.  We need to call that function instead of trying to
@@ -1711,11 +1707,6 @@ uint64_t Simulator::ReverseBytes(uint64_t value, ReverseByteMode mode) {
 
 
 void Simulator::VisitDataProcessing2Source(Instruction* instr) {
-  // TODO(mcapewel) move these to a higher level file, as they are global
-  //                assumptions.
-  ASSERT((static_cast<int32_t>(-1) >> 1) == -1);
-  ASSERT((static_cast<uint32_t>(-1) >> 1) == 0x7FFFFFFF);
-
   Shift shift_op = NO_SHIFT;
   int64_t result = 0;
   switch (instr->Mask(DataProcessing2SourceMask)) {
@@ -2917,7 +2908,6 @@ void Simulator::Debug() {
       } else if ((strcmp(cmd, "print") == 0) || (strcmp(cmd, "p") == 0)) {
         if (argc == 2) {
           if (strcmp(arg1, "all") == 0) {
-            // TODO(all): better support for printing in the debugger.
             PrintRegisters(true);
             PrintFPRegisters(true);
           } else {