On MIPS, uses more branch delay slots.

runtime/vm/assembler_mips.h

Index: runtime/vm/assembler_mips.h
===================================================================
--- runtime/vm/assembler_mips.h	(revision 22187)
+++ runtime/vm/assembler_mips.h	(working copy)
@@ -171,6 +171,9 @@
   // a stub frame.
   void EnterStubFrame(bool uses_pp = false);
   void LeaveStubFrame(bool uses_pp = false);
+  // A separate macro for restoring the SP that we can put in the delay slot
+  // of jumps that often follow LeaveStubFrame.
+  void LeaveStubFrameSPRestore(bool uses_pp = false);

[regis, 2013/05/01 01:21:46]

I think it would be clearer to leave LeaveStubFrame untouched (it would restore
sp as before) and add instead a LeaveStubFrameAndRet that would make use of the
delay slot.

[zra, 2013/05/01 16:53:17]

Done.

 
   // Instruction pattern from entrypoint is used in dart frame prologs
   // to set up the frame and save a PC which can be used to figure out the