[src/trunk]: src/sys/net Two tweaks: don't use a temporary register to derefe...

[alnsn <alnsn%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/bc0d56b9edcb
branches:  trunk
changeset: 797563:bc0d56b9edcb
user:      alnsn <alnsn%NetBSD.org@localhost>
date:      Tue Jul 22 08:29:51 2014 +0000

description:
Two tweaks: don't use a temporary register to dereference the err agrument
after xcall and don't generate ((tmp1 & 0xf) << 2) twice in emit_msh().

diffstat:

 sys/net/bpfjit.c |  59 +++++++++++++++----------------------------------------
 1 files changed, 16 insertions(+), 43 deletions(-)

diffs (117 lines):

diff -r 3f4e3564550a -r bc0d56b9edcb sys/net/bpfjit.c
--- a/sys/net/bpfjit.c  Tue Jul 22 08:20:08 2014 +0000
+++ b/sys/net/bpfjit.c  Tue Jul 22 08:29:51 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: bpfjit.c,v 1.29 2014/07/22 08:20:08 alnsn Exp $        */
+/*     $NetBSD: bpfjit.c,v 1.30 2014/07/22 08:29:51 alnsn Exp $        */
 
 /*-
  * Copyright (c) 2011-2014 Alexander Nasonov.
@@ -31,9 +31,9 @@
 
 #include <sys/cdefs.h>
 #ifdef _KERNEL
-__KERNEL_RCSID(0, "$NetBSD: bpfjit.c,v 1.29 2014/07/22 08:20:08 alnsn Exp $");
+__KERNEL_RCSID(0, "$NetBSD: bpfjit.c,v 1.30 2014/07/22 08:29:51 alnsn Exp $");
 #else
-__RCSID("$NetBSD: bpfjit.c,v 1.29 2014/07/22 08:20:08 alnsn Exp $");
+__RCSID("$NetBSD: bpfjit.c,v 1.30 2014/07/22 08:29:51 alnsn Exp $");
 #endif
 
 #include <sys/types.h>
@@ -612,19 +612,11 @@
                        return status;
        }
 
-       /* tmp2 = *err; */
-       status = sljit_emit_op1(compiler,
-           SLJIT_MOV_UI,
-           BJ_TMP2REG, 0,
+       /* if (*err != 0) return 0; */
+       jump = sljit_emit_cmp(compiler,
+           SLJIT_C_NOT_EQUAL|SLJIT_INT_OP,
            SLJIT_MEM1(SLJIT_LOCALS_REG),
-           offsetof(struct bpfjit_stack, err));
-       if (status != SLJIT_SUCCESS)
-               return status;
-
-       /* if (tmp2 != 0) return 0; */
-       jump = sljit_emit_cmp(compiler,
-           SLJIT_C_NOT_EQUAL,
-           BJ_TMP2REG, 0,
+           offsetof(struct bpfjit_stack, err),
            SLJIT_IMM, 0);
        if (jump == NULL)
                return SLJIT_ERR_ALLOC_FAILED;
@@ -989,24 +981,6 @@
        if (status != SLJIT_SUCCESS)
                return status;
 
-       /* tmp1 &= 0xf */
-       status = sljit_emit_op2(compiler,
-           SLJIT_AND,
-           BJ_TMP1REG, 0,
-           BJ_TMP1REG, 0,
-           SLJIT_IMM, 0xf);
-       if (status != SLJIT_SUCCESS)
-               return status;
-
-       /* tmp1 = tmp1 << 2 */
-       status = sljit_emit_op2(compiler,
-           SLJIT_SHL,
-           BJ_XREG, 0,
-           BJ_TMP1REG, 0,
-           SLJIT_IMM, 2);
-       if (status != SLJIT_SUCCESS)
-               return status;
-
 #ifdef _KERNEL
        over_mchain_jump = sljit_emit_jump(compiler, SLJIT_JUMP);
        if (over_mchain_jump == NULL)
@@ -1035,6 +1009,12 @@
        if (status != SLJIT_SUCCESS)
                return status;
 
+       label = sljit_emit_label(compiler);
+       if (label == NULL)
+               return SLJIT_ERR_ALLOC_FAILED;
+       sljit_set_label(over_mchain_jump, label);
+#endif
+
        /* tmp1 &= 0xf */
        status = sljit_emit_op2(compiler,
            SLJIT_AND,
@@ -1044,7 +1024,7 @@
        if (status != SLJIT_SUCCESS)
                return status;
 
-       /* tmp1 = tmp1 << 2 */
+       /* X = tmp1 << 2 */
        status = sljit_emit_op2(compiler,
            SLJIT_SHL,
            BJ_XREG, 0,
@@ -1053,13 +1033,6 @@
        if (status != SLJIT_SUCCESS)
                return status;
 
-
-       label = sljit_emit_label(compiler);
-       if (label == NULL)
-               return SLJIT_ERR_ALLOC_FAILED;
-       sljit_set_label(over_mchain_jump, label);
-#endif
-
        return SLJIT_SUCCESS;
 }
 
@@ -2107,8 +2080,8 @@
        sljit_compiler_verbose(compiler, stderr);
 #endif
 
-       status = sljit_emit_enter(compiler, 2, nscratches(hints),
-           nsaveds(hints), sizeof(struct bpfjit_stack));
+       status = sljit_emit_enter(compiler,
+           2, nscratches(hints), nsaveds(hints), sizeof(struct bpfjit_stack));
        if (status != SLJIT_SUCCESS)
                goto fail;