Emit standard DWARF3 opcode for TLS address

[Geod24]

DW_OP_GNU_push_tls_address is a GNU extension prior to DWARF2.
DWARF3 introduced DW_OP_form_tls_address with the exact same semantic, as can be seen here:

• https://sourceware.org/legacy-ml/gdb-patches/2016-08/msg00222.html
• https://reviews.llvm.org/rL274366

Caveat: GDB support was "only" added in 7.12, which was released on 2016-10-07.

Since I don't use DMD (debug infos are utterly broken on MacOSX), I didn't observe any downside of this, but I was going over the DWARF code and found this oddity and figured it was time to replace it.

CC @ibuclaw

[dlang-bot]

Thanks for your pull request, @Geod24!

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Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#11087"

[thewilsonator]

Looks fine to me.

[ibuclaw]

Ok. Compiler should support the latest gdb/dwarf features, and gdb should support old versions of compilers. Not the other way around.

[thewilsonator]

Test runnable/gdb4181.d failed.  The logged output:
/media/disk1/braddr/sandbox/at-client/pull-4031940-Linux_32/dmd/generated/linux/release/32/dmd -conf= -m32 -Irunnable -g  -odgenerated/runnable -ofgenerated/runnable/gdb4181_0  runnable/gdb4181.d 
gdb generated/runnable/gdb4181_0 --batch -x generated/runnable/gdb4181_0.gdb
Breakpoint 1 at 0x8048687: file runnable/gdb4181.d, line 22.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, D main () at runnable/gdb4181.d:23
23	}
RESULT=generated/runnable/gdb4181_0.gdb:5: Error in sourced command file:
Unhandled dwarf expression opcode 0x9b


==============================
Test runnable/gdb4181.d failed: 
GDB regex: 'RESULT=.*33' didn't match output:
----
Breakpoint 1 at 0x8048687: file runnable/gdb4181.d, line 22.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, D main () at runnable/gdb4181.d:23
23	}
RESULT=generated/runnable/gdb4181_0.gdb:5: Error in sourced command file:
Unhandled dwarf expression opcode 0x9b

----

[Geod24]

gdb (gdb): GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.5) 7.11.1

Sigh
So I guess we can't do that.

[WalterBright]

Saved it for the future.

[WalterBright]

https://issues.dlang.org/show_bug.cgi?id=20792