[pypy-commit] pypy stmgc-c4: reintroduce the medium fastpath for PRIVATE_FROM_PROTECTED objects

[Raemi]

Author: Remi Meier <remi.meier at gmail.com>
Branch: stmgc-c4
Changeset: r68660:1f646fa9a6ac
Date: 2014-01-14 10:28 +0100
http://bitbucket.org/pypy/pypy/changeset/1f646fa9a6ac/

Log:	reintroduce the medium fastpath for PRIVATE_FROM_PROTECTED objects

diff --git a/rpython/jit/backend/x86/assembler.py b/rpython/jit/backend/x86/assembler.py
--- a/rpython/jit/backend/x86/assembler.py
+++ b/rpython/jit/backend/x86/assembler.py
@@ -529,6 +529,31 @@
         mc = codebuf.MachineCodeBlockWrapper()
         #
         if not for_frame:
+            if descr.stmcat in ['A2W', 'A2V']:
+                # slow fastpath
+                # check if PRIV_FROM_PROT is set, but not
+                # WRITE_BARRIER
+                mc.MOV_rs(X86_64_SCRATCH_REG.value, WORD)
+                
+                flag = StmGC.GCFLAG_WRITE_BARRIER >> 32
+                off = 4
+                assert 0 < flag < 256
+                mc.TEST8_mi((X86_64_SCRATCH_REG.value, off), flag)
+                mc.J_il8(rx86.Conditions['NZ'], 0)
+                jz1 = mc.get_relative_pos()
+                # if flag set, jump over the next check & RET
+                
+                flag = StmGC.GCFLAG_PRIVATE_FROM_PROTECTED >> 40
+                off = 5
+                assert 0 < flag < 256
+                mc.TEST8_mi((X86_64_SCRATCH_REG.value, off), flag)
+                mc.J_il8(rx86.Conditions['Z'], 0)
+                jz2 = mc.get_relative_pos()
+                # if PRIV_F_PROT, RET
+                mc.RET()
+                mc.overwrite(jz2 - 1, chr(mc.get_relative_pos() - jz2))
+                mc.overwrite(jz1 - 1, chr(mc.get_relative_pos() - jz1))
+                
             self._push_all_regs_to_frame(mc, [], withfloats, callee_only=True)
             if IS_X86_32:
                 # we have 2 extra words on stack for retval and we pass 1 extra