Tag Archives: tools

Eclipse 4.2 Juno and C projects detecting include paths

Eclipse moved from 3.7 right up to 4.2, and it includes Lua now as well, so I thought I’d have a quick go at trying it out on some C projects again. It was less than awesome, but well, that’s eclipse I guess.

I chose File->New->”Makefile project with existing sources”, and selected the path to my project. I can’t find a combined “clean and build” but I cleaned and built, and it all mostly sort of worked.

Except, it completely failed to recognise the -I and -L flags from my Makefile. Which are important. That’s why they’re there. So, it builds, but you can’t navigate to any of the libraries you’re using, and your screen is full of red errors about undefined fields.

Under Project Properties->C/C++ build->Discovery options, there’s an unchecked setting for “Automate discovery…” but checking it just produces a warning that this is deprecated, and to use, “Preprocessor include paths, macros, etc” Good fucking job eclipse. Why have an option that you’ve decided to remove.

So, Project Properties->C/C++ General->Preprocessor include paths… (What’s the difference between build and general? fuck knows, classic eclipse UI design) And then “CDT GCC Build Output Parser”

Now, I never would have actually found this, but they have this pattern that’s apparently meant to help it find the calls to GCC in the makefile output. The default is (gcc)|([gc]\+\+)|(clang)

Now, on linux, by default, “cc” is gcc. and if you don’t override the CC variable in your own makefile, it will be invoked as cc. Which eclipse then completely ignores. I know that it’s not a good idea to always assume that cc is gcc, but hey, if it detected nothing when I ran the build, perhaps it should offer some other alternatives? Perhaps it should try and run cc and look at it’s version? Perhaps it should follow the symlinks?

If you want to fix it, use this text instead (gcc)|([gc]\+\+)|(clang)|(cc)
Then do a clean, a build, then right click your project, chose index, and choose rebuild.

Presto. The eclipse way.

Static analysis for AVR code with Splint

Over on #avr, static analysis came up, particularly, getting Splint to run. _abc_ put this guide together, which I’ve reproduced verbatim below.

Running splint(1) on avr-gcc source code

Version 0.0 - tested 15.05.2012

by _abc_ @irc.freenode.org

software versions:
splint 3.1.2 compiled from source
avr-gcc-4.5.1 as supplied by Atmel (binary build for Linux)

Splint is a static C source code analyzer which can help
keep C source files and headers tidy and consistent. It can
also prevent a lot of silly errors, which is more important
in embedded C code than elsewhere. Many embedded code error
signals involve smoke, sparks, and lost devices.

Splint was never designed to run on embedded C, with its
extensions. In addition to that, splint has not been maintained
that much. The Wikipedia article on splint mentions that is is
'not relevant' as software anymore and that its Wikipedia page
should be removed. I disagree with that statement.

The following shows how splint (3.1.2) can be run successfully
on abr-gcc source code in 2012.


1. Install splint (it compiles cleanly from source on any gnu
compiler equipped system, using ./configure && make && sudo
make install). Alternately, get the distribution specific
package of splint if it exists.

2. Make a copy of your embedded source files for backup in case
something goes wrong.

3. Get used to the fact that the splint manual page is not so
useful. Running splint -help [something] 2>&1|less is much more
so. The pdf manual which comes in the package of splint 3.1.2 is
dated 2003 (proudly, on the first page). That's okay, since the
C standard most used today is dated 1999 (C99)...

4. Copy the following commands into a shell command file in
your project directory, and edit the relevant parts (path to
avr installed toolchain include, source file name etc):

# splint-avr-gcc-code.sh 644
# V0.0 tested 15.05.2012 by _abc_ @ irc.freenode.org
# run the splint static source analyzer on a avr-gcc C source code file,
# in a avr-gcc compatible way.
# initial revision, tested with avr-gcc, throws lots of warnings on avr-gcc
# includes but runs AS LONG AS:
# i. __fuses and __lockbits sections are hidden from splint using 
#    #ifndef S_SPLINT_S
#      ...
#    #endif
# ii. any binary constants (0b000f) in the C source are either rewritten as
#   decimal or hex numbers, OR their sections are guarded as above, and
#   binary or hex values are provided instead.
# Comment: the splint parser should be patched to accept binary constants.
# The usual makefile used for project building should have a new section
# (target) called lint or splint which should lint the source. It can be
# easily written by adding the code below:

## adjust to suit your installation
AVR_TOOLCHAIN_INSTALLED_LOCATION="/some/where/" ;# edit me

SRC="mysource.c" ;# edit me, ONE source file per shell file for now

DEFS="-D__AVR_ATmega8__" ;# etc, edit this

## actually run
splint \
	-preproc \
	-unrecogcomments \

5. while editing the required areas of the command file above, also 
read its header. It explains how the source can be splint proofed. It is
really easy. The -unrecogcomments comment is needed because there are
some semantic comments in the header files which throw errors. The other
ways to splint proof your code are explained by executing the commands:

  splint -help parseerrors 2>&1|less

in a shell.

6. splint should really be updated with embedded C extensions, especially
the 0b0001 style binary constant support.

7. avr-libc maintainers should run splint as above on sources which include
them (hello_world.c with just #include  and #include  are
enough for a start), as splint shows more than 90 warnings on running through
the avr-libc headers included by the simple main alluded to above at the
time of this writing.

-- the end --

Note, I haven’t actually used splint myself, on AVR code or regular desktop code. I do however endorse static analysis, having used PMD and friends on java code quite a lot. If you don’t like splint, or are looking for alternatives, perhaps something still being maintained, abcminiuser suggests Cppcheck, which covers both C and C++. There’s also the commercial Coverity and gimpel. I’ve not used any of these, but it seemed like such a worthwhile record that I was loathe to lose the discussion the depths of IRC logs.

Early impressions with PyDev 2.2 and Eclipse 3.7

I’ve been happily using netbeans for C/C++ and python work, which works well enough to not really complain much. Mostly, I want IntelliJ for C code. I find eclipse big and clunky and awkward on the keyboard, and just generally a pain. No Eclipse, I do NOT want to have some sort of “workspace” I want you to just leave things where they are on the disk. Anyway, in Oracle’s infinite wisdom, they are continuing to destroy things that Sun built, and python support has been dropped in netbeans 7. A pity, as netbeans 7 added some nice debugging support for C/C++, and netbeans is much more tightly integrated than eclipse. Still a pale shadow of IntelliJ, but I digress.

So, I had to go and look for some alternative python editors. I’m currently trying out PyDev 2.2 with Eclipse 3.7. It mostly works ok too. It’s capable of running some unit tests, and has the basic highlighting and so on. However, it’s completion is not as good as I would like, nor think it should be. Take this for example.

def something(self):
    self.mylist = []
    # on this line, self.mylist. will give me the full builtin completion for lists
    self.otherlist = "blah blah".split()
    # split returns a list, but self.otherlist. has no completion here

It seems this can be worked around by “pre declaring” the type.

def something(self):
  self.somelist = []
  self.somelist = "blah blah".split()
  # self.somelist. produces full completion for list here....

This is…. odd?

Possibly related is that in python unit tests, I at least, normally use the self.assertEquals(left, right, msg) form, probably because I came from Java. However, self.assertEquals in PyDev doesn’t give me any completion guidance on the parameters at all. It turns out that in the implementation of python’s unittest, assertEquals is simply an alias for another function (assertEqual = assertEquals = failUnlessEqual) For whatever reason, this means that I get full completion and parameter help if I use the _real_ implementation, failUnlessEqual but no advice/help whatsoever if I use the assertEquals form.

Google says this is unhelpful.

  • “self.assertEquals python” returns 74300 results
  • “self.failUnlessEqual python” returns 35800 results

Update: this assertEquals vs failUnlessEqual is apparently only a problem for python < 2.7. Unfortunately debian stable (squeeze) at present still uses python 2.6 :( In more mundane items, I would _really_ like to know how to get IntelliJ's "ctrl-W" shortcut, for expanding a selection. (From the cursor in the middle of "karl" in the following line, 'self.wop = "this is karl in python".split()', pressing ctrl-w once would highlight 'karl', once more would select 'this is karl in python' (without the quotes), once more with the quotes, and then on to the entire rvalue, then the entire line. This stackoverflow post mentions a solution, but it doesn’t seem to work in PyDev windows, even after getting into the keymap and adding a “Select Enclosing Element” for the PyDev views (or the editor scope? the difference being?) it still doesn’t work.

Oh well, life goes on.