Re: [PATCH v2] arch/x86/tools/gen-insn-attr-x86.awk: remove duplicateconst

[Masami Hiramatsu]

(2012/12/10 10:34), H. Peter Anvin wrote:
> You're changing the array from an array of insn_attr_t to pointers to insn_attr_t?

No, please look at the code carefully,

-	print "const insn_attr_t const *inat_escape_tables[INAT_ESC_MAX + 1]" \
                                      ^^
+	print "const insn_attr_t * const inat_escape_tables[INAT_ESC_MAX + 1]" \
                                ^^
Both are pointers of array.

I'd just change the position of const.

const insn_attr_t const * -> const insn_attr_t * const

Thank you,

> 
> Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> wrote:
> 
>> (2012/12/10 10:03), H. Peter Anvin wrote:
>>> Yes, if you add a * it becomes an array of pointers.
>>
>> Right, I would like to make each pointer in the array read-only.
>>
>> And, of course, the data itself which pointed by the pointer
>> is already protected.
>> You can see this in (builddir)/arch/x86/lib/inat_table.c
>> ----
>> /* Table: 2-byte opcode (0x0f) */
>> const insn_attr_t inat_escape_table_1[INAT_OPCODE_TABLE_SIZE] = {
>> [...]
>> /* Escape opcode map array */
>> const insn_attr_t * const inat_escape_tables[INAT_ESC_MAX +
>> 1][INAT_LSTPFX_MAX +
>> 1] = {
>>        [1][0] = inat_escape_table_1,
>> ----
>>
>> So I think Cong's v3 is good :)
>>
>> Thank you,
>>
>>>
>>> Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> wrote:
>>>
>>>> (2012/12/10 0:50), H. Peter Anvin wrote:
>>>>> No, that would really be wrong - changing the type.
>>>>
>>>> What would be wrong? IMHO, this is just a fix to add a fool
>>>> proof 'const' to array instance itself.
>>>> ...Or, am I missed anything?
>>>>
>>>> Thank you,
>>>>
>>>>> Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> wrote:
>>>>>
>>>>>> (2012/12/08 8:17), Cong Ding wrote:
>>>>>>>>>>>> Patch description please?
>>>>>>>>>>> there are 2 consts in the definition of one variable
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Please put in an actual patch description.  The first line
>>>>>> (subject
>>>>>>>>>> line) is a title; the patch should make sense without it.
>>>>>>>>> sorry for that. so like this is fine?
>>>>>>>>>
>>>>>>>>
>>>>>>>> Well, except that typically you should explain which variable it
>>>> is.
>>>>>>>> Yes, it is obvious if you look at the patch, but you're making
>> the
>>>>>>>> reader spend a few more moments than necessary.
>>>>>>>>
>>>>>>>> Also, you should explain what the harm is -- if it breaks
>> anything
>>>>>>>> or is just a cosmetic issue.
>>>>>>> sorry again for lacking of experience...
>>>>>>> and I missed another same error, so send version 2.
>>>>>>
>>>>>> Ah, sorry for my mistake. I would like to make both the value
>>>>>> pointed by the pointers and the pointers itself read-only.
>>>>>> Thus the right way of the patch should be;
>>>>>>
>>>>>> -	print "const insn_attr_t const *inat_escape_tables[INAT_ESC_MAX
>> +
>>>> 1]"
>>>>>> \
>>>>>> +	print "const insn_attr_t * const inat_escape_tables[INAT_ESC_MAX
>> +
>>>>>> 1]" \
>>>>>>
>>>>>> Cong, could you update your patch? then I can Ack that.
>>>>>>
>>>>>> Thank you,
>>>>>>
>>>>>>>
>>>>>>> - cong
>>>>>>> ---
>>>>>>> From 6cf729b913287a6fc06325ca75ccf0efff9274e8 Mon Sep 17 00:00:00
>>>>>> 2001
>>>>>>> From: Cong Ding <dinggnu@xxxxxxxxx>
>>>>>>> Date: Fri, 7 Dec 2012 23:14:32 +0000
>>>>>>> Subject: [PATCH] arch/x86/tools/gen-insn-attr-x86.awk: remove
>>>>>> duplicate const
>>>>>>>
>>>>>>> fix the following sparse warning:
>>>>>>> arch/x86/lib/inat-tables.c:1080:25: warning: duplicate const
>>>>>>> arch/x86/lib/inat-tables.c:1095:25: warning: duplicate const
>>>>>>> arch/x86/lib/inat-tables.c:1118:25: warning: duplicate const
>>>>>>>
>>>>>>> for variable inat_escape_tables, inat_group_tables, and
>>>>>> inat_avx_tables
>>>>>>>
>>>>>>> Signed-off-by: Cong Ding <dinggnu@xxxxxxxxx>
>>>>>>> ---
>>>>>>>  arch/x86/tools/gen-insn-attr-x86.awk |    6 +++---
>>>>>>>  1 files changed, 3 insertions(+), 3 deletions(-)
>>>>>>>
>>>>>>> diff --git a/arch/x86/tools/gen-insn-attr-x86.awk
>>>>>> b/arch/x86/tools/gen-insn-attr-x86.awk
>>>>>>> index ddcf39b..987c7b2 100644
>>>>>>> --- a/arch/x86/tools/gen-insn-attr-x86.awk
>>>>>>> +++ b/arch/x86/tools/gen-insn-attr-x86.awk
>>>>>>> @@ -356,7 +356,7 @@ END {
>>>>>>>  		exit 1
>>>>>>>  	# print escape opcode map's array
>>>>>>>  	print "/* Escape opcode map array */"
>>>>>>> -	print "const insn_attr_t const *inat_escape_tables[INAT_ESC_MAX
>> +
>>>>>> 1]" \
>>>>>>> +	print "const insn_attr_t *inat_escape_tables[INAT_ESC_MAX + 1]"
>> \
>>>>>>>  	      "[INAT_LSTPFX_MAX + 1] = {"
>>>>>>>  	for (i = 0; i < geid; i++)
>>>>>>>  		for (j = 0; j < max_lprefix; j++)
>>>>>>> @@ -365,7 +365,7 @@ END {
>>>>>>>  	print "};\n"
>>>>>>>  	# print group opcode map's array
>>>>>>>  	print "/* Group opcode map array */"
>>>>>>> -	print "const insn_attr_t const *inat_group_tables[INAT_GRP_MAX
>> +
>>>>>> 1]"\
>>>>>>> +	print "const insn_attr_t *inat_group_tables[INAT_GRP_MAX + 1]"\
>>>>>>>  	      "[INAT_LSTPFX_MAX + 1] = {"
>>>>>>>  	for (i = 0; i < ggid; i++)
>>>>>>>  		for (j = 0; j < max_lprefix; j++)
>>>>>>> @@ -374,7 +374,7 @@ END {
>>>>>>>  	print "};\n"
>>>>>>>  	# print AVX opcode map's array
>>>>>>>  	print "/* AVX opcode map array */"
>>>>>>> -	print "const insn_attr_t const *inat_avx_tables[X86_VEX_M_MAX +
>>>>>> 1]"\
>>>>>>> +	print "const insn_attr_t *inat_avx_tables[X86_VEX_M_MAX + 1]"\
>>>>>>>  	      "[INAT_LSTPFX_MAX + 1] = {"
>>>>>>>  	for (i = 0; i < gaid; i++)
>>>>>>>  		for (j = 0; j < max_lprefix; j++)
>>>>>>>
>>>>>
>>>
> 


-- 
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx


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