[GHC] #14261: ghc stopped recognizing some arm triplets that used to work: Failed to lookup the datalayout for armv7a-hardfloat-linux-gnueabi; available targets:

[GHC]

#14261: ghc stopped recognizing some arm triplets that used to work: Failed to
lookup the datalayout for armv7a-hardfloat-linux-gnueabi; available
targets:
-------------------------------------+-------------------------------------
        Reporter:  slyfox            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by angerman):

 * cc: bgamari, kavon (added)


Comment:

 Just for the record. The `*-hardfloat-*` vendor seems to be gentoo
 specific:
 https://gitweb.gentoo.org/repo/gentoo.git/tree/eclass/toolchain.eclass#n1069.

 The `gen-data-layout.sh` script actually interrogates `clang`, to obtain
 the `data-layout`,
 cpu, and additional flags. Frankly the additional flags are still a bit
 fragile.

 I'm ok with adding:
 `armv7a-unknown-linux-gnueabi` to the list of llvm-targets. The case of
 `armv7a-hardfloat-linux-gnueabi`, which is not recognized as a proper llvm
 target, and llvm would only recognize as `armv7a-unknown-linux-gnueabihf`,
 I'm a bit reluctant to add, as it would result in a seemingly accepted
 target, while llvm would generate code for soft float, which seem
 unintentional.

 The customizable vendor flag though, I believe we should allow. I'm not
 perfectly sure if we should just strip it out in autoconf, and replace any
 vendor that's not part of the llvm-targets, with `unknown` as a fallback.

 E.g. `x86_64-UNREG-linux-gnu` would end up as `LLVM_TARGET=x86_64-unknown-
 linux-gnu`.

 I'm also more comfortable to make the `*-hardfloat-*-gnueabi` gentoo hack
 into a special casing in the configure script to have it end up as
 `LLVM_TARGET=...-unknown-...-gnueabihf`.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14261#comment:3>
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