Dear Monks,

I have been asked to test the LLVM environment for compiling Perl on Linux, similar to what BrowserUK did for windows. At first, I used the Debian “squeeze” Release 'apt-get' to get the LLVM package version 2.7. It installed fine, but couldn't compile Perl5.16.0.

I contacted Sylvestre Ledru who quickly responded that "Perl seems to build fine during my latest rebuild with clang 3.1." So I set out to build the LLVM environment from source. The steps are below and hopefully I used the <readmore> correctly.

Just a caution, this takes a lot of time to compile and may need as much as 3GB of space. So plan accordingly. Also notice that

../llvm/configure --enable-optimized --disable-assertions
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mkdir /home/llvm/             # Home directory for LLVM versions
cd /home/llvm/            # change directory to LLVM HOME
mkdir llvm-3.2.src/        # make directory for version
cd llvm-3.2.src/            # change directory for LLVM verson

# Creates the 'llvm' directory in /home/llvm/llvm-3.2.src/
#     This gives the directory structure for the build process

svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm

cd llvm/tools            # where to install clang

# Creates the 'clang' directory in /home/llvm/llvm-3.2.src/llvm/tools/
svn co http://llvm.org/svn/llvm-project/cfe/trunk clang

cd ../projects/            # where to install compiler-rt
svn co http://llvm.org/svn/llvm-project/compiler-rt/trunk compiler-rt
cd ..
mkdir build/
cd build/
## Update: added --enable-jit to next line to always enable
../llvm/configure --enable-optimized --disable-assertions --enable-jit
+ 

## Update: next line was missing 'make' first, then 'make check-all' t
+o test
make

make check-all
### note: using clang: '/home/llvm/llvm-3.1.src/build/Release/bin/clan
+g'

make update

/home/llvm/llvm-3.1.src/build# ./Release/bin/clang -v
clang version 3.2 (trunk 163314)
Target: i386-pc-linux-gnu
Thread model: posix

/home/llvm/llvm-3.1.src/build# make install

make -C runtime install-bytecode

make install
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cd /home/pyr/PRODUCTS/perl/perllvm

email7:/home/pyr/PRODUCTS/perl/perllvm# clang -v
clang version 3.2 (trunk 163323)
Target: i386-pc-linux-gnu
Thread model: posix

tar -xf./perl-5.16.0.tar
cd  perl-5.16.0 
./Configure -des  -Dprefix=/usr/opt/perllVm -Dusethreads -Dcc=clang -D
+ccflags='-O2'
make
make tests
make install
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We now have a Perl 5.16.0 built with 'clang' 3.1. 100% of the Perl tests ran correctly, which says good things about the 5.16.0 distribution. Some tests follow. I tested the Debian default 5.10.0, a 5.16.0 that I compiled with 'gcc' and finally the 5.16.0 built with 'clang'.

email7:/home/pyr/PRODUCTS/perl/perllvm# cat BrowserUK_991333.pl
#!perl -sw
use strict;
use 5.010;
use Time::HiRes qw[ time ];
no warnings 'recursion';

sub Ack {
    my( $M, $N ) = @_;
    return $N + 1           if $M == 0;
    return Ack( $M - 1, 1 ) if $N == 0;
    return Ack( $M - 1, Ack( $M, $N - 1 ) );
}

my $start = time;
say Ack( @ARGV );
say 'Took: ', time() - $start;



email7:/home/pyr/PRODUCTS/perl/perllvm# perl5.10.0 -sw BrowserUK_99133
+3.pl 3 9
4093
Took: 15.1458311080933

email7:/home/pyr/PRODUCTS/perl/perllvm# perl5.16.0 -sw BrowserUK_99133
+3.pl 3 9
4093
Took: 15.2425358295441

email7:/home/pyr/PRODUCTS/perl/perllvm# perllvm -sw BrowserUK_991333.p
+l 3 9
4093
Took: 14.7814569950104

email7:/home/pyr/Git/FB# time perl5.16.0  FBtest.plx
## Start: VSZ-8008_KB-0 RSS-5108_KB-0  BLOCK: 2048/8/2048 ( 1,000,000 
+)
...
## End: VSZ-50332 RSS-47468  Diff:42324|42360_KB-0  BLOCK: 2048

real    15m5.879s
user    14m24.102s
sys     0m38.442s

email7:/home/pyr/Git/FB# time perllvm  FBtest.plx  
## Start: VSZ-8008_KB-0 RSS-5108_KB-0  BLOCK: 2048/8/2048 ( 1,000,000 
+)
...
## End: VSZ-50332 RSS-47468  Diff:42324|42360_KB-0  BLOCK: 2048

real    15m33.238s
user    14m45.243s
sys     0m41.359s
[download]

In summary it doesn't look great yet, but I didn't use the JIT LLVM. You need to modify the Perl source to take advantage of it, and that will be another post.

Thank you