ARM: Fix jumptargets to actually merge virtual frames....

src/arm/virtual-frame-arm.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 54 matching lines @@
   where_to_go.top_of_stack_state_ = R0_TOS;
   MergeTo(&where_to_go);
   // Pop the register off the stack so it is detached from the frame.
   element_count_ -= 1;
   top_of_stack_state_ = NO_TOS_REGISTERS;
 }
 
 
 void VirtualFrame::MergeTo(VirtualFrame* expected) {
   if (Equals(expected)) return;
+  MergeTOSTo(expected->top_of_stack_state_);
+  ASSERT(register_allocation_map_ == expected->register_allocation_map_);
+}
+
+
+void VirtualFrame::MergeTOSTo(
+    VirtualFrame::TopOfStack expected_top_of_stack_state) {
 #define CASE_NUMBER(a, b) ((a) * TOS_STATES + (b))
-  switch (CASE_NUMBER(top_of_stack_state_, expected->top_of_stack_state_)) {
+  switch (CASE_NUMBER(top_of_stack_state_, expected_top_of_stack_state)) {
     case CASE_NUMBER(NO_TOS_REGISTERS, NO_TOS_REGISTERS):
       break;
     case CASE_NUMBER(NO_TOS_REGISTERS, R0_TOS):
       __ pop(r0);
       break;
     case CASE_NUMBER(NO_TOS_REGISTERS, R1_TOS):
       __ pop(r1);
       break;
     case CASE_NUMBER(NO_TOS_REGISTERS, R0_R1_TOS):
       __ pop(r0);
@@ skipping 60 matching lines @@
       break;
     case CASE_NUMBER(R1_R0_TOS, R0_R1_TOS):
       __ Swap(r0, r1, ip);
       break;
     case CASE_NUMBER(R1_R0_TOS, R1_R0_TOS):
       break;
     default:
       UNREACHABLE();
 #undef CASE_NUMBER
   }
-  ASSERT(register_allocation_map_ == expected->register_allocation_map_);
+  top_of_stack_state_ = expected_top_of_stack_state;
 }
 
 
 void VirtualFrame::Enter() {
   Comment cmnt(masm(), "[ Enter JS frame");
 
 #ifdef DEBUG
   // Verify that r1 contains a JS function.  The following code relies
   // on r2 being available for use.
   if (FLAG_debug_code) {
@@ skipping 452 matching lines @@
       return;
     }
   }
   EnsureOneFreeTOSRegister();
   top_of_stack_state_ = kStateAfterPush[top_of_stack_state_];
   Register dest = kTopRegister[top_of_stack_state_];
   __ Move(dest, reg);
 }
 
 
+void VirtualFrame::OverwriteStackPosition(Register reg, int this_far_down) {
+  int virtual_elements = kVirtualElements[top_of_stack_state_];
+  if (this_far_down == 0) {
+    Pop();
+    Register dest = GetTOSRegister();
+    if (dest.is(reg)) {
+      // We already popped one item off the top of the stack.  If the only
+      // free register is the one we were asked to push then we have been
+      // asked to push a register that was already in use, which cannot
+      // happen.  It therefore folows that there are two free TOS registers:
+      ASSERT(top_of_stack_state_ == NO_TOS_REGISTERS);
+      dest = dest.is(r0) ? r1 : r0;
+    }
+    __ mov(dest, reg);
+    EmitPush(dest);
+  } else if (this_far_down == 1) {
+    int virtual_elements = kVirtualElements[top_of_stack_state_];
+    if (virtual_elements < 2) {
+      __ str(reg, ElementAt(this_far_down));
+    } else {
+      ASSERT(virtual_elements == 2);
+      ASSERT(!reg.is(r0));
+      ASSERT(!reg.is(r1));
+      Register dest = kBottomRegister[top_of_stack_state_];
+      __ mov(dest, reg);
+    }
+  } else {
+    ASSERT(this_far_down >= 2);
+    ASSERT(virtual_elements <= 2);
+    __ str(reg, ElementAt(this_far_down));
+  }
+}
+
+
 Register VirtualFrame::GetTOSRegister() {
   if (SpilledScope::is_spilled()) return r0;
 
   EnsureOneFreeTOSRegister();
   return kTopRegister[kStateAfterPush[top_of_stack_state_]];
 }
 
 
 void VirtualFrame::EmitPush(Operand operand) {
   element_count_++;
@@ skipping 62 matching lines @@
     default:
       UNREACHABLE();
       break;
   }
   ASSERT(register_allocation_map_ == 0);  // Not yet implemented.
 }
 
 #undef __
 
 } }  // namespace v8::internal