[Fix] GoTLS function offset

[wlingze]

No description provided.

[wlingze]

I have created some test cases for the docker arm64 binary file, See #2 for details.
When i use IdaPro, readelf or simplely retrieve all symbols from *elf.File, it works and I obtain the correct address.
When I use *gosym.Table, the address is incorrect. address = 0x00635cb0
Also, when *gosym.Table is built, the data contains errors.

you can set a condition breakpoint in /usr/lib/go/src/debug/gosym/pclntab.go at line 308 with i==6626, where the *gosym.Func is built.

And I used go-parser with IdaPro, which shows that gopclntab contains incorrect data.

in this address: data(0x238980) + .textbase(0x3fd1e0) = 0x00635cb0

There's another thing:
I've previously built some simple binary files for testing, see #1, and they run well after removing the IdaProOffset.

So debug/gosym get wrong address, because binary file gopclntable data wrong or need other calculate.

debug/gosym get wrong, but go-parser get correct data.

in go-parser use this text-start:

in debug/gosym use this text-start:

[wlingze]

why this f.textStart error?

this f.textStart data from here:
/usr/lib/go/src/debug/gosym/pclntab.go:258

and this t.PC come from NewLineTable, in code ~/ecapture/user/config/config_gotls.go:333.

in other side, go-parser get this textStart data from pclntbl table.

rootcause:

debug/gosym use PC passed by call NewLineTable for textStart.
But this textStart should get from pclntable.

The relevant code changed by go pr 366695

solution:

1. use symbols from *elf.File like nopie case, you can get correct address. (Checked)
2. use symbols get runtime.text address, pass to NewLineTable, like go pr 366695 (NoChecked)