R devel - Mar 2011 - Does R use "computed gotos" - a gcc extension of C?

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.

I'd love to track down this problem, so R can build with gcc. R is used in
the
Sage maths project

http://www.sagemath.org/

and R is the only component of Sage which will not build with gcc on 64-bit 
Solaris x86. Many components will not build with Sun Studio, but this R issue 
means we need to have two compilers, not just one.

-- 
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.
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Dave

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
>
> I'd love to track down this problem, so R can build with gcc. R is used
in
> the Sage maths project
>
> http://www.sagemath.org/
>
> and R is the only component of Sage which will not build with gcc on 64-bit
> Solaris x86. Many components will not build with Sun Studio, but this R
issue
> means we need to have two compilers, not just one.
>
>
-- 
Luke Tierney
Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
241 Schaeffer Hall                  email:      luke at stat.uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu