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After a few weeks of mindnumbing work on treehydra gutts, I finally have something exciting to talk about!

We will be presenting  Dehydra at the GCC Developer’s Summit in lovely Ottawa. The GCC version of Dehydra exceeded all of my expectations, so it will be exciting to meet awesome GCC hackers who lay the groundwork to make this possible. Got suggestions for other venues to present Dehydra?

Packaging Help Needed

I feel that the Dehydra concept is getting mature enough for a 1.0 release. Recently baked GCC 4.3 means I’ll be able to distribute a 4.3-specific plugin patch(currently it’s against trunk, aka 4.4to-be). Now I need README, LICENSE, configure files, etc.

I will need help with packaging dehydra + patched gcc into .dpkg and .rpm files. Leave a comment, email me/static analysis list or poke me in #mmgc on irc.mozilla.org if you can help with packaging.

Logo/Mascot Wanted

Since every serious project has a cool mascot, it would be cool to get one for Dehydra. I’d be curious to see what people think could symbolize a code scanning monster that makes grep feel inadequate. I have a feeling a cartoon version of a giant Heavy Metal Duck might be it, but I haven’t made up my mind yet.

Treehydra What?

Treehydra is a work-in-progress name for the low-level equivalent of Dehydra. Currently it is built as separate GCC plugin. I haven’t yet made up mind on whether Treehydra will end up extending Dehydra or stay a separate tool. Since treehydra needs dehydra for bootstrap, they’ll stay separate for now.

Last week I managed to run treehydra to completition on my mozilla checkout and walk the resulting AST in JS correctly. Now comes the fun part of making it do useful tricks.

I got this question in the mail today.

Seems like a simple enough question, but grep won’t provide that answer It also happens to be an excellent usecase for Dehydra.

My script:

var classes = []
function process_type (c) {
if (!/class|struct/(c.kind)) return
classes.push (c.name)
}

function input_end() {
var f = this.aux_base_name + ".counter"
print(f)
write_file (f, classes.join ("\n"))
}

process_type is called every time GCC hits a class declaration or a template is instantiated(also for enums and unions, but those get ignored with the .kind check). Then input_end is called when GCC is done processing the file. this.aux_base_name is the input filename.

I hooked up this script to the mozilla build by adding the following to .mozconfig:

export CXX=$HOME/gcc/bin/g++
export CXXFLAGS="-fplugin=$HOME/work/gccplugin/gcc_dehydra.so -fplugin-arg=$HOME/work/gccplugin/test/count_classes.js"

Then I built:

make -f client.mk build WARNINGS_AS_ERRORS=

Count:

find -name \*.counter|xargs cat |sort |uniq > /tmp/classes.txt
wc /tmp/classes.txt


Answer: 15001

There are a million other trivial queries that could be accomplished in a similar manner that weren’t easy or possible before.

Update: Fixed typo, had an extra zero in the answer