Commit e3a22b53 authored by Benjamin Philip's avatar Benjamin Philip Committed by Julia Lawall
Browse files

Documentation: Coccinelle: document debug log handling 



The current debug documentation does not mention that logs are printed
to stdout unless DEBUG_FILE is set. It also doesn't mention that
Coccinelle cannot overwrite debug files.

Document this behaviour in the examples and reference it in the
debugging section.

Signed-off-by: default avatarBenjamin Philip <benjamin.philip495@gmail.com>
Signed-off-by: default avatarJulia Lawall <julia.lawall@inria.fr>
parent bb1c9ccf

Documentation/dev-tools/coccinelle.rst

+16 −5
Original line number Diff line number Diff line
@@ -127,6 +127,18 @@ To enable verbose messages set the V= variable, for example:: 


   make coccicheck MODE=report V=1



By default, coccicheck will print debug logs to stdout and redirect stderr to

/dev/null. This can make coccicheck output difficult to read and understand.

Debug and error messages can instead be written to a debug file instead by

setting the ``DEBUG_FILE`` variable::



    make coccicheck MODE=report DEBUG_FILE="cocci.log"



Coccinelle cannot overwrite a debug file. Instead of repeatedly deleting a log

file, you could include the datetime in the debug file name::



    make coccicheck MODE=report DEBUG_FILE="cocci-$(date -Iseconds).log"



Coccinelle parallelization

--------------------------
@@ -208,11 +220,10 @@ include options matching the options used when we compile the kernel. 
You can learn what these options are by using V=1; you could then

manually run Coccinelle with debug options added.



Alternatively you can debug running Coccinelle against SmPL patches

by asking for stderr to be redirected to stderr. By default stderr

is redirected to /dev/null; if you'd like to capture stderr you

can specify the ``DEBUG_FILE="file.txt"`` option to coccicheck. For

instance::

An easier approach to debug running Coccinelle against SmPL patches is to ask

coccicheck to redirect stderr to a debug file. As mentioned in the examples, by

default stderr is redirected to /dev/null; if you'd like to capture stderr you

can specify the ``DEBUG_FILE="file.txt"`` option to coccicheck. For instance::



    rm -f cocci.err

    make coccicheck COCCI=scripts/coccinelle/free/kfree.cocci MODE=report DEBUG_FILE=cocci.err