Avoiding repacking payload for v8::Arguments and v8::AccessorInfo (arm).

src/arm/stub-cache-arm.cc

Index: src/arm/stub-cache-arm.cc
===================================================================
--- src/arm/stub-cache-arm.cc	(revision 5834)
+++ src/arm/stub-cache-arm.cc	(working copy)
@@ -607,18 +607,18 @@
   if (Heap::InNewSpace(callback)) {
     info_loaded = true;
     __ Move(r0, Handle<CallHandlerInfo>(optimization.api_call_info()));
-    __ ldr(r6, FieldMemOperand(r0, CallHandlerInfo::kCallbackOffset));
+    __ ldr(r5, FieldMemOperand(r0, CallHandlerInfo::kCallbackOffset));
   } else {
-    __ Move(r6, Handle<Object>(callback));
+    __ Move(r5, Handle<Object>(callback));
   }
   Object* call_data = optimization.api_call_info()->data();
   if (Heap::InNewSpace(call_data)) {
     if (!info_loaded) {
       __ Move(r0, Handle<CallHandlerInfo>(optimization.api_call_info()));
     }
-    __ ldr(r5, FieldMemOperand(r0, CallHandlerInfo::kDataOffset));
+    __ ldr(r6, FieldMemOperand(r0, CallHandlerInfo::kDataOffset));
   } else {
-    __ Move(r5, Handle<Object>(call_data));
+    __ Move(r6, Handle<Object>(call_data));
   }
 
   __ add(sp, sp, Operand(1 * kPointerSize));
@@ -1081,11 +1081,11 @@
                       name, miss);
 
   // Push the arguments on the JS stack of the caller.
-  __ push(receiver);  // Receiver.
-  __ push(reg);  // Holder.
+  __ push(receiver);  // Receiver

[antonm, 2010/11/17 14:10:32]

nit: probably change R -> r as you remove a dot.

[SeRya, 2010/11/17 15:36:29]

Reverted change in this line.

   __ mov(ip, Operand(Handle<AccessorInfo>(callback)));  // callback data

[antonm, 2010/11/17 14:10:32]

why such a change, __ Push(reg, ip, name_reg) apparently should have done the
trick, what am I missing

[SeRya, 2010/11/17 15:36:29]

It would work, but generates more instructions. |Push| preferes arguments with
decreasing codes. ip=r13, scratch3=r4, name_reg=r0|r2. So here are 2 decreasing
subsequences. Actually I was wrong (thought it needs increasing codes) and now
fixing.

-  __ ldr(reg, FieldMemOperand(ip, AccessorInfo::kDataOffset));
-  __ Push(ip, reg, name_reg);
+  __ ldr(scratch3, FieldMemOperand(ip, AccessorInfo::kDataOffset));
+  __ Push(reg, scratch3, ip);
+  __ push(name_reg);
 
   // Do tail-call to the runtime system.
   ExternalReference load_callback_property =
@@ -1208,15 +1208,15 @@
       // holder_reg is either receiver or scratch1.
       if (!receiver.is(holder_reg)) {
         ASSERT(scratch1.is(holder_reg));
-        __ Push(receiver, holder_reg, scratch2);
-        __ ldr(scratch1,
+        __ ldr(scratch3,

[antonm, 2010/11/17 14:10:32]

why scratch3?  it looks like the diff might be made easier to read by something
like:

__ Push(receiver, holder_reg);
__ ldr(....)
__ Push(.......)

[SeRya, 2010/11/17 15:36:29]

Done.

                FieldMemOperand(holder_reg, AccessorInfo::kDataOffset));
-        __ Push(scratch1, name_reg);
+        __ Push(receiver, holder_reg, scratch3);
+        __ Push(scratch2, name_reg);
       } else {
         __ push(receiver);
         __ ldr(scratch1,
                FieldMemOperand(holder_reg, AccessorInfo::kDataOffset));
-        __ Push(holder_reg, scratch2, scratch1, name_reg);
+        __ Push(holder_reg, scratch1, scratch2, name_reg);
       }
 
       ExternalReference ref =