Date: Sat, 19 Jul 2003 09:24:06 -0700 From: Marcel Moolenaar <marcel@xcllnt.net> To: Alexander Kabaev <kabaev@mail.ru> Cc: threads@freebsd.org Subject: Re: Some more on TLS Message-ID: <20030719162406.GA16766@dhcp01.pn.xcllnt.net> In-Reply-To: <20030719095406.02c51beb.kabaev@mail.ru> References: <20030719045625.GB45759@dhcp01.pn.xcllnt.net> <20030719095406.02c51beb.kabaev@mail.ru>
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On Sat, Jul 19, 2003 at 09:54:06AM -0400, Alexander Kabaev wrote:
>
> > o There's no assembler support for TLS on i386 and amd64.
>
> amd64 is new and TLS is probably not activated enabled in binutils yet.
>
> i386 assebmly thing: what do you mean?
>
> % cat test.c
> .section ".tdata","awT",@progbits
> foo: .long 25
> .text
> movl %gs:0, %eax
> leal foo@TLSGD(,%ebx,1), %eax
> leal foo@TLSLDM(%ebx), %eax
> leal foo@DTPOFF(%eax), %edx
> movl foo@GOTTPOFF(%ebx), %eax
> subl foo@GOTTPOFF(%ebx), %eax
> addl foo@GOTNTPOFF(%ebx), %eax
> movl foo@INDNTPOFF, %eax
> movl $foo@TPOFF, %eax
> subl $foo@TPOFF, %eax
> leal foo@NTPOFF(%ecx), %eax
Our in-tree compiler emits assembly that our assembler doesn't like.
Given the following C program:
\begin{c}
int __thread i = 3;
int x()
{
return i;
}
\end{c}
Our compiler emits:
\begin{as}
.file "t.c"
.globl %li
.section .tdata,"awT",@progbits
.p2align 2
.type %li, @object
.size %li, 4
%li:
.long 3
.text
.p2align 2,,3
.globl x
.type x, @function
x:
pushl %ebp
movl %esp, %ebp
movl %gs:0, %eax
movl %li@NTPOFF(%eax), %eax
leave
ret
.size x, .-x
.ident "GCC: (GNU) 3.3.1 [FreeBSD] 20030711 (prerelease)"
\end{as}
And the assembler does not like that:
/var/tmp//ccVMU4H6.s: Assembler messages:
/var/tmp//ccVMU4H6.s:2: Warning: rest of line ignored; first ignored character is `%'
/var/tmp//ccVMU4H6.s:5: Error: unrecognized symbol type "li"
/var/tmp//ccVMU4H6.s:5: Warning: rest of line ignored; first ignored character is `,'
/var/tmp//ccVMU4H6.s:6: Error: expected comma after name `' in .size directive
/var/tmp//ccVMU4H6.s:6: Warning: rest of line ignored; first ignored character is `%'
/var/tmp//ccVMU4H6.s:7: Warning: rest of line ignored; first ignored character is `%'
/var/tmp//ccVMU4H6.s:17: Error: bad register name `%li@NTPOFF(%eax)'
It's probably just the %l and %G prefix, but it makes the use of the
__thread keyword rather pointless at this time.
--
Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net
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