[Lldb-commits] [PATCH] D19604: Allow ObjectFilePECOFF to initialize with ARM binaries.

Renato Golin via lldb-commits lldb-commits at lists.llvm.org
Tue May 3 01:37:21 PDT 2016

rengolin added a comment.

In http://reviews.llvm.org/D19604#419284, @sas wrote:

> - We don't use thumb-* triples in lldb as far as I can see. Thumb is handled just fine regardless of the triple.

This is a good strategy. Thumb is an instruction set, the "arm-" in the triple means the Architecture.

> - `pc` vs `unknown` doesn't seem to matter either, and other code in this file uses `pc` (see a few lines above).

AFAIK, "pc" is accepted but ignored, just like "unknown" and "gobbedygook".

> - I could just use `arm` instead of `armv7` but as far as I know, Windows Phone is a pure thumb environment, so the CPUs used will be armv7 and up.

Er, this doesn't make sense. ARM cores support Thumb ever since ARMv4T (ARM7, circa '97). Thumb2, which is the version supported by ARMv7 cores, exists since ARMv6 (ARM11, circa '03).

It's best if you keep the triple free of sub-architecture choices and use -march to pick the right one. But some platforms have chosen to specify it on the triple, and we may have to follow suit to be compatible.

> - I could add support for aarch64 in this file, but I've got no way of testing it at the moment, and it seems likes a bad idea to advertise support for something we can't even test.


> Given all of these, it seems like sticking with `armv7-pc-windows` or using `arm-pc-windows` might be the better solutions. Let me know what you guys think.

"arm-pc-windows" seems good to me. I'm also ok with "armv7-pc-windows" if that's the "accepted" triple on Windows world.



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