/*! @page uhood_tech Coding Standard and Technical Considerations
+This page describes the software infrastructure behind the SimGrid
+project. This is not the components' organisation (described in @ref
+uhood_arch) but informations on how to extend the framework, how the
+automatic tests are run, and so on. These informations are split on
+several pages, as follows:
-There is two main things you want to know about the internals of
-SimGrid. First, you need to understand the component organization, as
-SimGrid is heavily layered, with each level being rather highly
-specialized and optimized toward a task. For that, please head to
-@ref uhood_arch.
-
-Then, if you work actively on the SimGrid project, the second point
-you need to understand is about the infrastructure of the SimGrid
-project, ie how to extend the framework in any way, how the automatic
-tests are run, and so on. These informations are split on several
-pages, as follows:
-
+ - @ref uhood_tech_inside
- @subpage inside_tests
- @subpage inside_doxygen
- @subpage inside_extending
- @subpage inside_cmake
- @subpage inside_release
-@section uhood_tech_codstand Coding Standard
+@section uhood_tech_inside Insiders Considerations
+
+@subsection uhood_tech_inside_config Extra configuration
+
+The default build configuration of SimGrid fits the user needs, but
+they are not adapted to the ones actually working on SimGrid. See @ref
+install_src_config for more information. Note that this is very
+different from runtime configuration.
+In particular, the build is configured by default to produce highly
+optimized binaries, at the price of high compilation time. The
+rationale is that users will compile SimGrid only once, and use it many
+times. This is exactly the contrary for the insiders, so you want to
+turn off \b enable_compile_optimizations.
+
+Symmetrically, \b enable_compile_warnings is off for the users because
+we don't want to bother them with compiler warnings (that abort the
+build in SimGrid), but any insider must turn this option on, or your
+code will be refused from the main repository.
+
+@verbatim
+ cmake -Denable_compile_optimizations=OFF \
+ -Denable_compile_warnings=ON .
+@endverbatim
+
+@subsection uhood_tech_inside_commit Interacting with git
+
+During the Gran Refactoring to SimGrid4, things are evolving rather
+quickly, and some changes impact a large amount of files. You should
+thus not have long-standing branches, because they will rot very
+quickly and you will suffer to merge them back. Instead, you should
+work as much as possible with incremental changes that do not break
+things, and get them directly in master.
+
+Your commit message should follow the git habits, explained in this
+<a href="http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html">blog
+post</a>, or in the
+<a href="https://github.com/atom/atom/blob/master/CONTRIBUTING.md#git-commit-messages">
+git styleguide of Atom</a>.
+
+
+@subsection uhood_tech_inside_codstand Automatically Enforcing our Coding Standards
+
If you plan to commit code to the SimGrid project, you definitely need
to install the relevant tool to ensure that your changes follow our
coding standards:
@verbatim
-sudo apt-get install clang-format-3.8
-ln -s $PWD/tools/git-hooks/clang-format.pre-commit .git/hooks/pre-commit
+# install clang-format
+sudo apt-get install clang-format-3.9 # debian
+
+# tell git to call the script on each commit
+ln -s $(realpath tools/git-hooks/clang-format.pre-commit) .git/hooks/pre-commit
@endverbatim
This will add an extra verification before integrating any commit that
to improve your commit. Just carefully read the error message you get
to find the exact command with git-apply to fix your formating.
+If you find that for a specific commit, the formatter does a very bad
+job, then add --no-verify to your git commit command line.
+
+@subsection uhood_tech_tricks Random Tricks
+
+Over the years, we accumulated a few tricks that make it easier to
+work with SimGrid. Here is a somewhat unsorted list of such tricks.
+
+### Easy testing
+
+Launching all tests can be very time consuming, so you want to build
+and run the tests in parallel. Also, you want to save the build output
+to disk, for further reference. This is exactly what the
+BuildSimGrid.sh script does. It is upper-cased so that the shell
+completion works and allow to run it in 4 key press: `./B<tab>`
+
+Note that if you build out of tree (as you should, see below), the
+script builds the build/default directory. I usually copy the file in
+each build/ subdir to test each of them separately.
+
+### Easy out of tree builds
+
+It is easy to break one build configuration or another. That's
+perfectly OK and we will not point fingers if it happens. But it is
+somewhat forbidden to leave the tree broken for more than one working
+day. Monitor the build daemons after you push something, and strive to
+fix any breakage ASAP.
+
+To easily switch between the configs without rebuilding everything,
+create a set of out of tree builds (as explained in @ref
+install_cmake_outsrc) in addition to your main build tree.
+To not mess with git, you want to put your build tree under the build/
+directory, which is ignored by git. For example, I have the following
+directories: build/clang build/java build/full
+(but YMMV).
+
+Then, the problem is that when you traverse these directories, you
+cannot edit the sources (that are in the srcdir, while you're in
+bindir). This makes it difficult to launch the tests and everything.
+
+To solve that issue, just call `make hardlinks` from your build dir.
+This will create hard links allowing to share every source files into
+the build dir. They are not copied, but hard linked. It means that
+each file is accessible under several names, from the srcdir and from
+the bindirs. If you edit a source file found under bindir, the srcdir
+version (visible to git) will also be changed (that's the same file,
+after all).
+
+Note that the links sometimes broken by git or others. Relaunching
+`make hardlinks` may help if you're getting incoherent build results.
+
+### Unsorted hints
+
+* If you want to debug memory allocation problems, here are a few hints:
+ - disable compiler optimizations, to have better backtraces;
+ - disable the mallocators, or it will be hard to match malloc's with free's;
+ - disable model checking, unless your problem lies in the model
+ checker part of SimGrid (MC brings its own malloc implementation,
+ which valgrind does not really love).
+ All this is configured with:
+
+ cmake -Denable_model-checking=OFF
+ -Denable_mallocators=OFF
+ -Denable_compile_optimizations=OFF .
+
+* If you break the logs, you want to define XBT_LOG_MAYDAY at the
+ beginning of log.h. It deactivates the whole logging mechanism,
+ switching to printfs instead. SimGrid becomes incredibly verbose
+ when doing so, but it you let you fixing things.
+
+
*/
