GHC build system does not detect opt-3.0 and friends

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So I'm not that familiar with the build system and m4 but looking at this.

However, wouldn't a user typically install llvm on Debian by installing the 'llvm' package. This installs the tools without version suffixes. Its arguable that in the case of a user installing llvm-3.0 package and not the llvm package we shouldn't be trying to handle this for them.

My concern is that I'll only be able to detect opt-3.0 or opt-2.7 or opt-3.2 by enumerating different version possibilities in the configure.ac. Which seems ugly...

Well, those distributions typically make the GHC package (which you may use for a bootstrap compiler) depend specifically on llvm-3.0, for those co-existence reasons. So out of the box, you're not necessarily aware that you need the llvm package, or that it's even there! This is very much the case on my ARM/Linux installs (Ubuntu 12.10.) This is the annoying bit. In general I just fix this by symlinking appropriately into my $HOME/bin.

I think you could probably encapsulate most of the hairy machinery in an m4 macro to search for 'llc-X.Y' and 'opt-X.Y' variants, after looking for non-suffixed versions.

assigned to @trac-dterei

Interesting. What do you mean by co-existence reasons sorry? This reason seems fairly compelling to me, just checked the ghc package on Ubuntu then. I'll sleep on it and write out the m4 macro tomorrow. (the ugliness of the macro isn't the concern, that is trivial, it's the maintenance of it for future llvm versions. Easy but annoying).

In my case I'm using llvm-3.0 because default llvm is 3.1, which has regressions when it comes to ARM.

I'd suggest searching for opt-* and then checking if llc-samething exists and using both if found. Hardcoding a list of known suffixes seems bad.

mentioned in commit 64aaaa19

closed

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Resolution	Unresolved → ResolvedFixed

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unassigned @trac-dterei

Hi David,

unfortunately this is not working on my Ubuntu 12.04.2 LTS on pandaboard. I do have both llc-3.0 and opt-3.0 in /usr/bin and in PATH:

$ which llc-3.0
/usr/bin/llc-3.0
$ which opt-3.0
/usr/bin/opt-3.0

but GHC's configure does not detect them. Configuring with simple ./configure ends with:

Configure completed successfully.

   Building GHC version  : 7.7.20130214

   Build platform        : arm-unknown-linux
   Host platform         : arm-unknown-linux
   Target platform       : arm-unknown-linux

   Bootstrapping using   : /usr/bin/ghc
      which is version   : 7.4.1

   Using gcc                 : /usr/bin/gcc
      which is version       : 4.6.3
   Building a cross compiler : NO

   ld       : /usr/bin/ld
   Happy    : /usr/bin/happy (1.18.9)
   Alex     : /usr/bin/alex (3.0.1)
   Perl     : /usr/bin/perl
   dblatex  : 
   xsltproc : 

   Using LLVM tools
      llc   : 
      opt   : 

   HsColour was not found; documentation will not contain source links

and settings file looks:

$ cat settings
[("GCC extra via C opts", " -fwrapv"),
 ("C compiler command", "/usr/bin/gcc"),
 ("C compiler flags", " -fno-stack-protector  -Wl,--hash-size=31 -Wl,--reduce-memory-overheads"),
 ("ld command", "/usr/bin/ld"),
 ("ld flags", "     --hash-size=31     --reduce-memory-overheads"),
 ("ld supports compact unwind", "YES"),
 ("ld supports build-id", "YES"),
 ("ld is GNU ld", "YES"),
 ("ar command", "/usr/bin/ar"),
 ("ar flags", "q"),
 ("ar supports at file", "YES"),
 ("touch command", "touch"),
 ("dllwrap command", "/bin/false"),
 ("windres command", "/bin/false"),
 ("perl command", "/usr/bin/perl"),
 ("target os", "OSLinux"),
 ("target arch", "ArchARM {armISA = ARMv7, armISAExt = [VFPv3,NEON], armABI = HARD}"),
 ("target word size", "4"),
 ("target has GNU nonexec stack", "False"),
 ("target has .ident directive", "True"),
 ("target has subsections via symbols", "False"),
 ("Unregisterised", "NO"),
 ("LLVM llc command", "llc"),
 ("LLVM opt command", "opt")
 ]

There are two issues with this patch I'm able to see now.

in aclocal.m4 in FIND_LLVM_PROG you use

    if test "$1" == ""; then

but this should be:

    if test "$$1" == ""; then

to result in for example "$LLC" == "" instead of "LLC" == ""

Ubuntu (and Debian probably does the same), installs LLVM-3.0 package into /usr/lib/llvm-3.0 directory and creates a links to opt/llc into /usr/bin with the prefixes -3.0. That means:

$ ls -la /usr/bin/llc-3.0 
lrwxrwxrwx 1 root root 23 Dec 11  2011 /usr/bin/llc-3.0 -> ../lib/llvm-3.0/bin/llc

The result is that your find test where you find for file will not work as this is not a file, but link. You will also need to find for link (i.e. -type l)

Both issues are fixed by attached patch.

Trac metadata

Trac field	Value
Resolution	ResolvedFixed → Unresolved

Attached file 0001-fix-Find-LLVM-tools-when-version-number-at-end-e.g.-.patch (download).

assigned to @trac-dterei

closed

Thanks Karel!

I went with a slightly modified version of your patch as I want configure to find the highest version of the llvm tools regardless if the some of the binaries are files or links.

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed

mentioned in commit c0437321

reopened

unassigned @trac-dterei

Trac field	Value
Version	7.7
Type	FeatureRequest
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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GHC build system does not detect opt-3.0 and friends

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