On 03/ 4/11 11:40 PM, luke-tier...@uiowa.edu wrote:
On Fri, 4 Mar 2011, Dr. David Kirkby wrote:

The R manual says R will not build with gcc on 64-bit Solaris x86 with
gcc

http://cran.r-project.org/doc/manuals/R-admin.html#Solaris

"Tests with gcc32 on ‘x86’ and ‘amd64’ have been less successful:
‘x86’ builds have failed on tests using complex arithmetic33, whereas
on ‘amd64’ the builds have failed to complete in several different
ways, most recently with relocation errors for libRblas.so. "

I know what the "relocation errors" problem is. That library (and in
fact two other R libraries) all have non-PIC code in them, despite the
fact the source is compiled with the -fPIC option.

http://blogs.sun.com/rie/entry/my_relocations_don_t_fit

shows how to prove this. If one runs this command on Solaris:

$ elfdump -d libRblas.so | fgrep TEXTREL

there is some output showing that theres non-PIC code present in the R
library.

R is compiled with -fPIC on Solaris, but certain things can cause
non-PIC code to be generated even with that option. One is by the use
of "computed gotos" which is a gcc extension. I'm wondering if R uses
any of these.

Yes -- in the byte code interpreter in eval.c

luke

Thank you Luke. Do you know if there may be any others?

Do you know if that bit of code gets compiled into all 3 of the R libraries? I tried replacing


#define NEXT() (__extension__ ({goto *(*pc++).v;}))


by a function which did absolutely nothing. The code built, but still had the library issues.

I'm almost certain that the definition of NEXT will cause problems, but I'm not convinced it is the only issue.

What happens if a non-GNU compiler is used? I assume these GNU extensions don't get used, so how comes the code builds? Is there any way I can disable the use of the GNU extensions, while still building with gcc.

It is rather annoying that the code has __extension__ in it, which disables the warnings about the use of GCC extensions.

http://gcc.gnu.org/onlinedocs/gcc/Alternate-Keywords.html

Why is there a need to hide the use of the extensions? I'd personally like to see just standard C used, without any extensions. Then problems like I'm having would be less likely to occur.


--
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

Dave

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