r? @brson

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My understanding is that gnueabihf originated in Debian, and defined to allow ARMv7 and Thumb-2. If the platform does not support ARMv7 and Thumb-2, it should use gnueabi, not gnueabihf.

Rust can choose to interpret gnueabi/gnueabihf differently, but there should be a good reason to do so.

I do think that many of our triples (especially these for embedded targets typically) are somewhat ad-hoc. Most of our "prior art" here in general has come from what clang does. The clang default cpu for this target is arm1136jf-s which is ARM v6 plus Thumb (not thumb2 I think).

From that wiki:

Some concern for fast-enough, pretty awesome (600MHz+) ARMv6 + VFPv2 processors here - i.MX37 etc. - which will not be supported by armhf default flavour, but.. we will have to live with that

An entire distro cannot afford the level of backward compatibility a compiler, like rustc, can.

And besides we're mostly talking about compiler runtime here (and jemalloc) - the codegen options can still be tweaked with -C flags so there's not going to be a whole lot of difference on armv7 (as long as both ISAs remain hard-float).

For llvm the default target for arm-unknown-linux-gnueabi is arm7tdmi, which is an ARMv4. However, rust tells llvm to use the v6 instructions: https://github.com/rust-lang/rust/blob/master/src/librustc_back/target/arm_unknown_linux_gnueabi.rs#L25.

As the ARM architecture is backward compatible maybe we should remove this restriction of setting v6 and rely to the compiler default.

It is quite unfortunate that GCC and Clang disagree, but I guess following Clang is as good as any choice.

I've verified this patch solves the issue I have, thanks!

@joerg-krause
That's a good point! Now that there's a modern ARMv7 target and ARMv6-hf takes care of the original Rpi, the soft-float target should at least cater to armv5.

I remember your fixing the target in question so why not start a discussion in a dedicated issue or PR?

@bors r+

📌 Commit d4fda66 has been approved by brson

@petevine I'll do it, if this comment gets accepted.

@alexcrichton Please consider to specify ARMv6 only for the hard-float target and specify as the default target architecture for the soft-float is the arm7tdmi CPU, which is an ARMv4. Or at least cater to ARMv5 as @petevine suggested. Note that the ARM architectures are backward-compatible.

⌛ Testing commit d4fda66 with merge 3154ede...

💔 Test failed - auto-linux-64-nopt-t

@bors: retry

On Thu, Feb 25, 2016 at 8:26 AM, bors notifications@github.com wrote:

[image: 💔] Test failed - auto-linux-64-nopt-t
http://buildbot.rust-lang.org/builders/auto-linux-64-nopt-t/builds/8174

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