0005260: ocaml compiler presents static link libraries to GCC backwards

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0005260

OCaml

OCaml general

public

2011-05-01 22:40

2011-05-17 16:08

Reporter

nacl

Assigned To

Priority

normal

Severity

major

Reproducibility

always

Status

resolved

Resolution

no change required

Platform

OS Version

Product Version

3.12.0

Target Version

Fixed in Version

Summary

0005260: ocaml compiler presents static link libraries to GCC backwards

Description

Yeah, the title says it all.

OS: Linux/openSUSE 11.4
Kernel Version: 2.6.37.6
Arch: x86_64

The openSUSE build service compiles static libraries with the --as-needed linker flag, which causes the statically linking against the pcre library fail with GCC linker errors. This likely extends to other libraries as well.

This can be set to ocamlc or ocamlopt by adding '-ccopt -Wl,--as-needed'

For example, compiling the attached file with

ocamlc.opt -verbose -g -o test.byt -thread -I /usr/lib64/ocaml/pcre/ /usr/lib64/ocaml/pcre/pcre.cma test.ml

Works fine. The relevant linker arguments are '-lpcre' and '-lpcre_stubs', in that order However, when called as:

ocamlc.opt -ccopt -Wl,--as-needed -verbose -g -o test.byt -thread -I /usr/lib64/ocaml/pcre/ /usr/lib64/ocaml/pcre/pcre.cma test.ml

It fails. However, It works when I explicitly add a 'cclib -lpcre' to the mix, like so:

ocamlc.opt -ccopt -Wl,--as-needed -cclib -lpcre -verbose -g -o test.byt -thread -I /usr/lib64/ocaml/pcre/ /usr/lib64/ocaml/pcre/pcre.cma test.ml

It works perfectly fine, dumping the pcre linker flags as -lpcre -lpcre_stubs -lpcre, with the last '-lpcre' appearing to be appended as a result of the '-cclib -lpcre' argument.

The linker args at the bottom of the pcre.cma file appear to be specified in the correct order of '-lpcre_stubs -lpcre' as was seen by opening it in a text editor. Attempting to reverse the order of the flags in the file resulted in the compiler segfaulting.

It was suggested that the problem is somehow related to a list reversal, but I do not know for sure.

Additional Information

This problem was first noted in this thread: //www.mail-archive.com/godi-list@ocaml-programming.de/msg00347.html">http://www.mail-archive.com/godi-list@ocaml-programming.de/msg00347.html [//www.mail-archive.com/godi-list@ocaml-programming.de/msg00347.html" target="_blank">^]

It was unclear whether this was a problem with pcre or ocaml itself, but Gerd seems to suggest that it was related to ocaml itself.

This bug is likely the same as described in http://caml.inria.fr/mantis/view.php?id=5234 [^]

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Attached Files

test.ml [^] (99 bytes) 2011-05-01 22:40

Relationships

related to

0005234

closed

ocamlopt -shared does not preserve order of -cclib options

Notes
(0005900) doligez (manager) 2011-05-17 16:08	When I compile pcre 6.2.2, the command line that compiles pcre.cmxa is the following: ocamlopt -a -cclib "-L/opt/local/lib -lpcre" -cclib -lpcre_stubs -o pcre.cmxa pcre.cmx Note that "-lpcre" and "-lpcre_stubs" appear in this order (which is the wrong order, given the strange semantics of the Unix linker). OCaml preserves this order, as it should. I strongly claim that the problem is in pcre itself: it should list -lpcre_stubs before -lpcre.

Issue History
Date Modified	Username	Field	Change
2011-05-01 22:40	nacl	New Issue
2011-05-01 22:40	nacl	File Added: test.ml
2011-05-02 12:47	doligez	Relationship added	related to 0005234
2011-05-16 16:36	doligez	Status	new => acknowledged
2011-05-17 16:08	doligez	Note Added: 0005900
2011-05-17 16:08	doligez	Status	acknowledged => resolved
2011-05-17 16:08	doligez	Resolution	open => no change required