Re: [PATCH] Add option -mfence-as-lock-add=[no|yes]

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Tue, Jan 26, 2016 at 5:13 AM, Andrew Senkevich
<andrew.n.senkevich@gmail.com> wrote:
> 2016-01-25 22:26 GMT+03:00 H.J. Lu <hjl.tools@gmail.com>:
>> On Mon, Jan 25, 2016 at 10:50 AM, Andrew Senkevich
>> <andrew.n.senkevich@gmail.com> wrote:
>>> Hi,
>>>
>>> this patch adds -mfence-as-lock-add=[no|yes] option.
>>> With -mfence-as-lock-add=yes lfence, mfence and sfence will be encoded
>>> as lock addl $0x0, (%{r,e}sp).
>>>
>>> gas/
>>>     * config/tc-i386.c (avoid_fence): New.
>>>     (output_insn): Encode as lock addl $0x0, (%{r,e}sp) if avoid_fence is true.
>>>     (OPTION_FENCE_AS_LOCK_ADD): New.
>>
>> Please rename OPTION_FENCE_AS_LOCK_ADD to
>> OPTION_MFENCE_AS_LOCK_ADD.
>>
>>>     (md_longopts): Add -mfence-as-lock-add.
>>>     (md_parse_option): Handle -mfence-as-lock-add.
>>>     (md_show_usage): Add -mfence-as-lock-add=[no|yes].
>>>     * doc/c-i386.texi (-mfence-as-lock-add): Document.
>>
>> The doc change is wrong:
>>
>> hjl@gnu-6 gas]$ make info
>> Making info in doc
>> make[1]: Entering directory
>> '/export/build/gnu/binutils/build-x86_64-linux/gas/doc'
>> restore=: && backupdir=".am$$" && \
>> rm -rf $backupdir && mkdir $backupdir && \
>> if (makeinfo --split-size=5000000 --split-size=5000000 --version)
>>>/dev/null 2>&1; then \
>>   for f in as.info as.info-[0-9] as.info-[0-9][0-9] as.i[0-9]
>> as.i[0-9][0-9]; do \
>>     if test -f $f; then mv $f $backupdir; restore=mv; else :; fi; \
>>   done; \
>> else :; fi && \
>> if makeinfo --split-size=5000000 --split-size=5000000 -I
>> "/export/gnu/import/git/sources/binutils-gdb/gas/doc" -I
>> "/export/gnu/import/git/sources/binutils-gdb/gas/../libiberty" -I
>> "/export/gnu/import/git/sources/binutils-gdb/gas/../bfd/doc" -I
>> ../../bfd/doc  -I /export/gnu/import/git/sources/binutils-gdb/gas/doc
>> \
>>  -o as.info `test -f 'as.texinfo' || echo
>> '/export/gnu/import/git/sources/binutils-gdb/gas/doc/'`as.texinfo; \
>> then \
>>   rc=0; \
>> else \
>>   rc=$?; \
>>   $restore $backupdir/* `echo "./as.info" | sed 's|[^/]*$||'`; \
>> fi; \
>> rm -rf $backupdir; exit $rc
>> /export/gnu/import/git/sources/binutils-gdb/gas/doc/c-i386.texi:337: misplaced {
>> /export/gnu/import/git/sources/binutils-gdb/gas/doc/c-i386.texi:337: misplaced }
>> Makefile:400: recipe for target 'as.info' failed
>> make[1]: *** [as.info] Error 1
>> make[1]: Leaving directory
>> '/export/build/gnu/binutils/build-x86_64-linux/gas/doc'
>> Makefile:2211: recipe for target 'info-recursive' failed
>> make: *** [info-recursive] Error 1
>> [hjl@gnu-6 gas]$
>>
>>> gas/testsuite/
>>>
>>>     * gas/i386/i386.exp: Run new tests.
>>>     * gas/i386/fence-as-lock-add.s: New.
>>>     * gas/i386/fence-as-lock-add-yes.d: Likewise.
>>>     * gas/i386/fence-as-lock-add-no.d: Likewise.
>>
>> Need 64-bit testcase.
>
> Please look at attached.
>

+  -mfence-as-lock-add=[no|yes]\n\
+                          encode lfence, mfence and sfence as\n\
+   lock addl $0x0, (%%{re}sp)\n"));

Please use space instead of tab here.

+sfence as @samp{lock addl $0x0, (%rsp)} for 64-bit case;
+as @samp{lock addl $0x0, (%esp)} for 32-bit case.

Please change it to

sfence as @samp{lock addl $0x0, (%rsp)} in 64-bit mode and
@samp{lock addl $0x0, (%esp)} in 32-bit mode.

+++ b/gas/testsuite/gas/i386/x86-64-fence-as-lock-add.s

Please remove it since it isn't used.


-- 
H.J.