__attribute__((__section__(x))) symbols generation problems

[llvmbot]

Bugzilla Link	3564
Resolution	FIXED
Resolved on	Feb 13, 2009 16:58
Version	unspecified
OS	FreeBSD
Attachments	test case
Reporter	LLVM Bugzilla Contributor
CC	@asl

Extended Description

when I compile the attached with clang and gcc I am getting different things:

lev /tmp$ gcc -c dataset.c; nm dataset.o
0000000000000000 r __set_foo_sym_bar.1873
0000000000000000 b bar
0000000000000000 T foo

lev /tmp$ ccc -c dataset.c ; nm dataset.o
ccc: Unknown host 'freebsd', using generic host information.
0000000000000000 b bar
0000000000000000 T foo
0000000000000000 d foo.__set_foo_sym_bar

[asl]

Roman, could you please attach assembler outputs?

[llvmbot]

gcc assembler

[llvmbot]

clang assembler

[asl]

Well, at least section is totally omitted from clang output. Could you please attach .bc file as well?

[llvmbot]

bc as requested

[asl]

Ok, so, this is clang problem - there is no section specified in .bc file for internal symbol

[llvmbot]

Incremental improvement here: http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20090209/012221.html

Note that this still won't work with -O2 because we aren't handling attribute used.

[llvmbot]

it does not work with -O1 either.

lev /tmp$ cat dataset.clang.nm
0000000000000000 b bar
0000000000000000 T foo
0000000000000000 d foo.__set_foo_sym_bar
lev /tmp$ cat dataset.gcc.nm
0000000000000000 r __set_foo_sym_bar.1873
0000000000000000 b bar
0000000000000000 T foo
lev /tmp$

note that the gcc puts this in read only data section while clang initialized data section. also the name differs

[llvmbot]

Proposed fix for marking the global as read-only
This fixed the read-only part of this for me. The test-suit does't show any regression, but I'm not sure if there are some weird cases.

[llvmbot]

the proposed fix does not make the FreeBSD kenrel link though so please dont close this. I'll come with another test case

[asl]

the proposed fix does not make the FreeBSD kenrel link though so please dont
close this. I'll come with another test case
What is the error message (from linker)?

[llvmbot]

the proposed fix does not make the FreeBSD kenrel link though so please dont
close this. I'll come with another test case
What is the error message (from linker)?

I analyzed it and found another problem..

http://llvm.org/bugs/show_bug.cgi?id=3572

if the proposed fix is accepted this can be closed. thnx!

[lattner]

Daniel, plz take a look at this patch when you have time, thanks!

[llvmbot]

Fixed here: http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20090209/012321.html