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From: Jan Beulich <jbeulich@suse.com>
To: Binutils <binutils@sourceware.org>
Subject: [PATCH 3/4] x86: avoid string copy when swapping Vex.W controlled operands
Date: Fri, 10 Jun 2022 15:35:52 +0200	[thread overview]
Message-ID: <c34029b6-a66e-8dab-1b42-87ee8da91af8@suse.com> (raw)
In-Reply-To: <6fd28ca0-2af4-7335-18d3-31036dea7a4f@suse.com>

Now that op_out[] is an array of pointers, there's no need anymore to
copy strings. Simply swap the pointers.

--- a/opcodes/i386-dis.c
+++ b/opcodes/i386-dis.c
@@ -13473,9 +13473,10 @@ OP_VexW (instr_info *ins, int bytemode,
   if (ins->vex.w)
     {
       /* Swap 2nd and 3rd operands.  */
-      strcpy (ins->scratchbuf, ins->op_out[2]);
-      strcpy (ins->op_out[2], ins->op_out[1]);
-      strcpy (ins->op_out[1], ins->scratchbuf);
+      char *tmp = ins->op_out[2];
+
+      ins->op_out[2] = ins->op_out[1];
+      ins->op_out[1] = tmp;
     }
 }
 
@@ -13503,9 +13504,10 @@ OP_REG_VexI4 (instr_info *ins, int bytem
   if (ins->vex.w)
     {
       /* Swap 3rd and 4th operands.  */
-      strcpy (ins->scratchbuf, ins->op_out[3]);
-      strcpy (ins->op_out[3], ins->op_out[2]);
-      strcpy (ins->op_out[2], ins->scratchbuf);
+      char *tmp = ins->op_out[3];
+
+      ins->op_out[3] = ins->op_out[2];
+      ins->op_out[2] = tmp;
     }
 }
 


  parent reply	other threads:[~2022-06-10 13:35 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-10 13:33 [PATCH 0/4] x86: follow-on to making disassembler thread-safe Jan Beulich
2022-06-10 13:35 ` [PATCH 1/4] x86: properly initialize struct instr_info instance(s) Jan Beulich
2022-06-10 13:35 ` [PATCH 2/4] x86: shrink prefix related disassembler state fields Jan Beulich
2022-06-10 13:35 ` Jan Beulich [this message]
2022-06-10 13:36 ` [PATCH 4/4] x86: replace global scratch buffer Jan Beulich
2022-06-13 13:59   ` H.J. Lu
2022-06-13 14:55     ` Jan Beulich
2022-06-13 20:58       ` H.J. Lu
2022-06-10 19:43 ` [PATCH 0/4] x86: follow-on to making disassembler thread-safe H.J. Lu
2022-06-13  7:54   ` Jan Beulich

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