Building Hiphop PHP gotcha

Tonight I’ve delved into the world of Facebook’s HipHop for PHP. Let me early on point out that I’m not doing so because I believe that I will need it any time soon, but I am convinced  that I without a shadow of a doubt  will be approached by customers who think they do, and I rather not have opinions or advise against things I haven’t tried myself or at least have a very good understanding of.

Unfortunately I set about this task on an RHEL 5.4 box, and it hasn’t been a walk in the park. Quite a few dependencies were out of date or didn’t exist in the repositories, libicu, boost, onig, tbb etc.

Though, CMake did a good job of telling me what was wrong, so it wasn’t a huge deal, I just compiled the missing pieces from source and put them in $CMAKE_PREFIX_PATH. One thing CMake didn’t pick up on however, was that the flex version shipped with current RHEL is rather outdated. Once I thought I had everything configured, I set about the compilation, and my joy was swiftly abrupted by this:

[  3%] [FLEX][XHPScanner] Building scanner with flex /usr/bin/flex version 2.5.4
/usr/bin/flex: unknown flag '-'.  For usage, try /usr/bin/flex --help

Not entirely sure what it was actually doing here, I took the shortcut of replacing /usr/bin/flex with a shell script which just exited after putting $@ in a file in /tmp/ and re-ran `make`. Looking in the resulting file, this is the argument flex is given:

-C --header-file=scanner.lex.hpp -o/home/erik/dev/hiphop-php/src/third_party/xhp/xhp/scanner.lex.cpp /home/erik/dev/hiphop-php/src/third_party/xhp/xhp/scanner.l

To me that looks quite valid, and there’s certainly no single – in that command line.

Long story short, flex introduced –header-file in a relatively “recent” version (2.5.33 it seems, but I may be wrong on that one, doesn’t matter). Unlike most other programs (using getopt), it won’t tell you “Invalid option ‘–header-file’”. So after compiling a newer version of flex, I was sailing again.