I give up.

[Jonathan Wilson]

ok, that tells me where the code is.
But that still doesnt tell me what any of the 1000s of different functions 
that relate to RTL actually DO.

What I need to output is something like this:
mov rega, dword ptr ds:__tls_index
mov regb, dword ptr fs:__tls_array
mov regc, [rega+regb*4]
then to get the address itself (ready to insert into the instruction), you do:
dword ptr ds:var[regc]

rega,regb,regc are registers
var is the address of the thread-local variable relative to the start of 
the segment that it resides in (and of course will be modified by the 
linker when all the segments are combined)

BTW, pre-calculating the value for regc isnt possible (because __tls_index 
can be changed at any time)

I have looked in all the code, all the manuals, all the documentation and 
all the resources that turn up on google but I still cant figure out how to 
do what I need :(.

I suspect that, since its target specific, someone that knows the i?86 
backend is going to need to help me.