(gdb) b syms_of_threads
Breakpoint 1 at 0x8245e40: file thread.c, line 1097.
(gdb) r -Q
Starting program: /home/eggert/src/gnu/emacs/master-tmp/src/temacs -Q
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Breakpoint 1, syms_of_threads () at thread.c:1097
(gdb) p &main_thread
$1 = (struct thread_state *) 0x85f2920 <main_thread>
(gdb) disas syms_of_threads
Dump of assembler code for function syms_of_threads:
=> 0x08245e40 <+0>:	push   %ebx
   0x08245e41 <+1>:	sub    $0x14,%esp
   0x08245e44 <+4>:	push   $0x8597340
   0x08245e49 <+9>:	call   0x8203e00 <defsubr>
   0x08245e4e <+14>:	movl   $0x8597320,(%esp)
   0x08245e55 <+21>:	call   0x8203e00 <defsubr>
   0x08245e5a <+26>:	movl   $0x8597300,(%esp)
   0x08245e61 <+33>:	call   0x8203e00 <defsubr>
   0x08245e66 <+38>:	movl   $0x85972e0,(%esp)
   0x08245e6d <+45>:	call   0x8203e00 <defsubr>
   0x08245e72 <+50>:	movl   $0x85972c0,(%esp)
   0x08245e79 <+57>:	call   0x8203e00 <defsubr>
   0x08245e7e <+62>:	movl   $0x85972a0,(%esp)
   0x08245e85 <+69>:	call   0x8203e00 <defsubr>
   0x08245e8a <+74>:	movl   $0x8597260,(%esp)
   0x08245e91 <+81>:	call   0x8203e00 <defsubr>
   0x08245e96 <+86>:	movl   $0x8597280,(%esp)
   0x08245e9d <+93>:	call   0x8203e00 <defsubr>
   0x08245ea2 <+98>:	movl   $0x8597240,(%esp)
   0x08245ea9 <+105>:	call   0x8203e00 <defsubr>
   0x08245eae <+110>:	movl   $0x8597460,(%esp)
   0x08245eb5 <+117>:	call   0x8203e00 <defsubr>
   0x08245eba <+122>:	movl   $0x8597440,(%esp)
   0x08245ec1 <+129>:	call   0x8203e00 <defsubr>
   0x08245ec6 <+134>:	movl   $0x8597420,(%esp)
   0x08245ecd <+141>:	call   0x8203e00 <defsubr>
   0x08245ed2 <+146>:	movl   $0x8597400,(%esp)
   0x08245ed9 <+153>:	call   0x8203e00 <defsubr>
   0x08245ede <+158>:	movl   $0x85973e0,(%esp)
   0x08245ee5 <+165>:	call   0x8203e00 <defsubr>
   0x08245eea <+170>:	movl   $0x85973c0,(%esp)
   0x08245ef1 <+177>:	call   0x8203e00 <defsubr>
   0x08245ef6 <+182>:	movl   $0x85973a0,(%esp)
   0x08245efd <+189>:	call   0x8203e00 <defsubr>
   0x08245f02 <+194>:	movl   $0x8597380,(%esp)
   0x08245f09 <+201>:	call   0x8203e00 <defsubr>
   0x08245f0e <+206>:	movl   $0x8597360,(%esp)
   0x08245f15 <+213>:	call   0x8203e00 <defsubr>
   0x08245f1a <+218>:	movl   $0x8597220,(%esp)
   0x08245f21 <+225>:	call   0x8203e00 <defsubr>
   0x08245f26 <+230>:	movl   $0x85f28e8,(%esp)
   0x08245f2d <+237>:	call   0x81b17a0 <staticpro>
   0x08245f32 <+242>:	pop    %edx
   0x08245f33 <+243>:	pop    %ecx
   0x08245f34 <+244>:	push   $0xd
   0x08245f36 <+246>:	push   $0x82acace
   0x08245f3b <+251>:	movl   $0x0,0x85f28e8
   0x08245f45 <+261>:	call   0x81ff540 <intern_c_string_1>
   0x08245f4a <+266>:	mov    %eax,%ebx
   0x08245f4c <+268>:	pop    %eax
   0x08245f4d <+269>:	pop    %edx
   0x08245f4e <+270>:	push   $0xe
   0x08245f50 <+272>:	push   $0x82acadc
   0x08245f55 <+277>:	call   0x81ff540 <intern_c_string_1>
   0x08245f5a <+282>:	add    $0xc,%esp
   0x08245f5d <+285>:	push   $0x0
   0x08245f5f <+287>:	push   %ebx
   0x08245f60 <+288>:	push   %eax
   0x08245f61 <+289>:	call   0x81b9d00 <Fdefalias>
   0x08245f66 <+294>:	pop    %ecx
   0x08245f67 <+295>:	pop    %ebx
   0x08245f68 <+296>:	push   $0x7
   0x08245f6a <+298>:	push   $0x82acb0d
   0x08245f6f <+303>:	call   0x81ff540 <intern_c_string_1>
   0x08245f74 <+308>:	pop    %edx
   0x08245f75 <+309>:	pop    %ecx
   0x08245f76 <+310>:	push   $0x0
   0x08245f78 <+312>:	push   %eax
   0x08245f79 <+313>:	call   0x81e15e0 <Fprovide>
   0x08245f7e <+318>:	add    $0xc,%esp
   0x08245f81 <+321>:	push   $0x85df124
   0x08245f86 <+326>:	push   $0x82acaeb
   0x08245f8b <+331>:	push   $0x85f28e0
   0x08245f90 <+336>:	call   0x82040e0 <defvar_lisp>
   0x08245f95 <+341>:	add    $0x10,%esp
   0x08245f98 <+344>:	cmpb   $0x0,0x85d64e0
   0x08245f9f <+351>:	movl   $0x85f2925,0x85df124
   0x08245fa9 <+361>:	jne    0x8245fbc <syms_of_threads+380>
   0x08245fab <+363>:	mov    0x85f2920,%eax
   0x08245fb0 <+368>:	and    $0x7f000000,%eax
   0x08245fb5 <+373>:	cmp    $0x54000000,%eax
   0x08245fba <+378>:	jne    0x8245fc1 <syms_of_threads+385>
   0x08245fbc <+380>:	add    $0x8,%esp
   0x08245fbf <+383>:	pop    %ebx
   0x08245fc0 <+384>:	ret
   0x08245fc1 <+385>:	push   %eax
   0x08245fc2 <+386>:	push   $0x46d
   0x08245fc7 <+391>:	push   $0x82acbfb
   0x08245fcc <+396>:	push   $0x82ac968
   0x08245fd1 <+401>:	call   0x81b1820 <die>
End of assembler dump.
(gdb) p &Vmain_thread
$2 = (Lisp_Object *) 0x85df124 <globals+740>
(gdb)