From: Alex <alexinbeijing@gmail.com>
To: musl@lists.openwall.com
Subject: Re: [PATCH 3/3] Add script to add CFI directives to asm files in debug builds of x86_64
Date: Fri, 2 Oct 2015 13:01:40 +0200 [thread overview]
Message-ID: <CACsECNcP8_Fo8DkQ=JJ3gNQKQ5+dZOAJFQLFrtoa1doff=k6og@mail.gmail.com> (raw)
In-Reply-To: <CACsECNfxjZeEww7bOovP06SVb=dP4tuQHRRj7zDU-ZFSJpz=bQ@mail.gmail.com>
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On Fri, Oct 2, 2015 at 12:58 PM, Alex <alexinbeijing@gmail.com> wrote:
>
> On Fri, Oct 2, 2015 at 12:19 PM, Rich Felker <dalias@libc.org> wrote:
>
>> On Fri, Oct 02, 2015 at 12:02:03PM +0200, Alex Dowad wrote:
>> > +# this does NOT exhaustively check for all possible instructions which
>> could
>> > +# overwrite a register value inherited from the caller (just the
>> common ones)
>> > +/mov.*,%r(ax|bx|cx|dx|si|di|bp|8|9|10|11|12|13|14|15)/ {
>> trashed(get_reg2()) }
>> > +/(add|addl|sub|subl|and|or|xor|lea|sal|sar|shl|shr)
>> %r(ax|bx|cx|dx|si|di|bp|8|9|10|11|12|13|14|15),/ {
>> > + trashed(get_reg1())
>> > +}
>>
>> This looks wrong but maybe it's already wrong in existing code. Why
>> are you marking the first operand as trashed rather than the second?
>
>
> You're absolutely right!
>
I'm pretty sure the reason I made this mistake was because of reading
Intel's developer manuals, where they write the destination register as the
first operand, and then absentmindedly applying the GNU syntax used by musl.
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next prev parent reply other threads:[~2015-10-02 11:01 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-02 10:02 [PATCH 1/3] Pull a couple common AWK functions for CFI scripts into separate file Alex Dowad
2015-10-02 10:02 ` [PATCH 2/3] When generating CFI for i386 asm, don't mistake an FDIV instruction for DIV Alex Dowad
2015-10-02 10:02 ` [PATCH 3/3] Add script to add CFI directives to asm files in debug builds of x86_64 Alex Dowad
2015-10-02 10:19 ` Rich Felker
2015-10-02 10:58 ` Alex
2015-10-02 11:01 ` Alex [this message]
2015-10-02 10:18 ` [PATCH 1/3] Pull a couple common AWK functions for CFI scripts into separate file Rich Felker
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