On Mon, 2023-08-07 at 14:31 -0400, Eric Feng wrote:
> On Fri, Aug 4, 2023 at 6:46 PM David Malcolm <dmalc...@redhat.com>
> wrote:
> >
> > On Fri, 2023-08-04 at 18:42 -0400, David Malcolm wrote:
> > > On Fri, 2023-08-04 at 16:48 -0400, Eric Feng wrote:
> > > > On Fri, Aug 4, 2023 at 11:39 AM David Malcolm
> > > > <dmalc...@redhat.com>
> > > > wrote:
> > > > >
> > > > > On Fri, 2023-08-04 at 11:02 -0400, Eric Feng wrote:
> > > > > > Hi Dave,
> > > > > >
> > > > > > Tests related to our plugin which depend on Python-specific
> > > > > > definitions have been run by including /* { dg-options "-
> > > > > > fanalyzer
> > > > > > -I/usr/include/python3.9" } */. This is undoubtedly not
> > > > > > ideal;
> > > > > > is
> > > > > > it
> > > > > > best to approach this problem by adapting a subset of
> > > > > > relevant
> > > > > > definitions like in gil.h?
> > > > >
> > > > > That might be acceptable in the very short-term, but to
> > > > > create a
> > > > > plugin
> > > > > that's useful to end-user (authors of CPython extension
> > > > > modules)
> > > > > we
> > > > > want to be testing against real Python headers.
> > > > >
> > > > > As I understand it, https://peps.python.org/pep-0394/ allows
> > > > > for
> > > > > distributors of Python to symlink "python3-config" in the
> > > > > PATH to
> > > > > a
> > > > > python3.X-config script (for some X).
> > > > >
> > > > > So on such systems running:
> > > > > python3-config --includes
> > > > > should emit the correct -I option. On my box it emits:
> > > > >
> > > > > -I/usr/include/python3.8 -I/usr/include/python3.8
> > > > >
> > > > >
> > > > > It's more complicated, but I believe:
> > > > > python3-config --cflags
> > > > > should emit the build flags that C/C++ extensions ought to
> > > > > use
> > > > > when
> > > > > building. On my box this emits:
> > > > >
> > > > > -I/usr/include/python3.8 -I/usr/include/python3.8 -Wno-
> > > > > unused-
> > > > > result -
> > > > > Wsign-compare -O2 -g -pipe -Wall -Werror=format-security -
> > > > > Wp,-
> > > > > D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -
> > > > > fstack-
> > > > > protector-strong -grecord-gcc-switches -m64 -mtune=generic
> > > > > -
> > > > > fasynchronous-unwind-tables -fstack-clash-protection -fcf-
> > > > > protection -
> > > > > D_GNU_SOURCE -fPIC -fwrapv -DDYNAMIC_ANNOTATIONS_ENABLED=1 -
> > > > > DNDEBUG -
> > > > > O2 -g -pipe -Wall -Werror=format-security -Wp,-
> > > > > D_FORTIFY_SOURCE=2
> > > > > -
> > > > > Wp,-
> > > > > D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -
> > > > > grecord-
> > > > > gcc-switches -m64 -mtune=generic -fasynchronous-unwind-
> > > > > tables -
> > > > > fstack-clash-protection -fcf-protection -D_GNU_SOURCE -fPIC -
> > > > > fwrapv
> > > > >
> > > > > and it's likely going to vary from distribution to
> > > > > distribution.
> > > > > Some
> > > > > of those options *are* going to affect the gimple that -
> > > > > fanalyzer
> > > > > "sees".
> > > > >
> > > > > Does your installation of Python have such a script?
> > > > >
> > > > > So in the short term you could hack in a minimal subset of
> > > > > the
> > > > > decls/defns from Python.h, but I'd prefer it if target-
> > > > > supports.exp
> > > > > gained a DejaGnu directive that invokes python3-config,
> > > > > captures
> > > > > the
> > > > > result (or fails with UNSUPPORTED for systems without python3
> > > > > development headers), and then adds the result to the build
> > > > > flags
> > > > > of
> > > > > the file being tested. The .exp files are implemented in
> > > > > Tcl,
> > > > > alas;
> > > > > let me know if you want help with that.
> > > > >
> > > > > Dave
> > > > Sounds good; thanks! Following existing examples in
> > > > target-supports.exp, the following works as expected in terms
> > > > of
> > > > extracting the build flags we are interested in.
> > > >
> > > > In target-supports.exp:
> > > > proc check_python_flags { } {
> > > > set result [remote_exec host "python3-config --cflags"]
> > > > set status [lindex $result 0]
> > > > if { $status == 0 } {
> > > > return [lindex $result 1]
> > > > } else {
> > > > return "UNSUPPORTED"
> > > > }
> > > > }
> > > >
> > > > However, I'm having some trouble figuring out the specifics as
> > > > to
> > > > how
> > > > we may add the build flags to our test cases. My intuition
> > > > looks
> > > > like
> > > > something like the following:
> > > >
> > > > In plugin.exp:
> > > > foreach plugin_test $plugin_test_list {
> > > > if {[lindex $plugin_test 0] eq "analyzer_cpython_plugin.c"}
> > > > {
> > > > set python_flags [check_python_flags]
> > > > if { $python_flags ne "UNSUPPORTED" } {
> > > > // append $python_flags to build flags here
> > > > }
> > > > }
> > > > ....
> > > > }
> > > >
> > > > How might we do so?
> > >
> > > Good question.
> > >
> > > Looking at plugin.exp I see it uses plugin-test-execute, which is
> > > defined in gcc/testsuite/lib/plugin-support.exp.
> > >
> > > Looking there, I see it attempts to build the plugin, and then if
> > > it
> > > succeeds, it calls
> > > dg-runtest $plugin_tests $plugin_enabling_flags $default_flags
> > > where $plugin_tests is the list of source files to be compiled
> > > using
> > > the plugin. So one way to do this would be to modify that code
> > > from
> > > plugin.exp to pass in a different value, rather than
> > > $default_flags.
> > > Though it seems hackish to special-case this.
> >
> > Sorry, I think I misspoke here; that line that uses $default_flags
> > is
> > from plugin-support.exp, not from plugin.exp; $default_flags is a
> > global variable.
> >
> > So I think my 2nd approach below may be the one to try:
> >
> > >
> > > As another way, that avoids adding special-casing to plugin.exp,
> > > there's an existing directive:
> > > dg-additional-options
> > > implemented in gcc/testsuite/lib/gcc-defs.exp which appends
> > > options
> > > to
> > > the default options. Unfortunately, it works via:
> > > upvar dg-extra-tool-flags extra-tool-flags
> > > which is a nasty Tcl hack meaning access the local variable named
> > > "dg-
> > > extra-tool-flags" in *the frame above*, referring to it as
> > > "extra-
> > > tool-
> > > flags". (this is why I don't like Tcl)
> > >
> > > So I think what could be done is to invoke your
> > > "check_python_flags"
> > > test as a directive from the test case, so that in target-
> > > supports.exp
> > > you'd have something like:
> > >
> > > proc dg-require-python-h {} {
> > >
> > > which could do the invocation/output-capture of python3-config,
> > > and
> > > would also have code similar to that in dg-additional-options to
> > > append
> > > to the options (or it could possibly just call dg-additional-
> > > options
> > > provided there's an "upvar" before the callsite to make the
> > > nested
> > > stack manipulation work).
> > >
> > > The individual test cases could then have:
> > >
> > > /* { dg-require-python-h } */
> > >
> > > in them.
> > >
> > > That way the Tcl stack at the point where the new directive runs
> > > should
> > > be similar enough to how dg-additional-options gets run for
> > > similar
> > > option-injection code to work (yuck!).
> Gotcha, thanks for the tip! I've been trying to make this approach
> work, but despite trying many things just having /* {
> dg-require-python-h } */ in the relevant test cases does not seem to
> invoke proc dg-require-python-h {} { ... } in target-supports.exp. Am
> I missing something else? Do we need to also "register" it somewhere
> else for it to recognize the command? For context, previously I was
> able to see the results of "check_python_flags" (i.e the output of
> python3-config) by invoking it in plugin.exp.
My understanding is that ultimately we call into DejGnu's dg.exp's dg-
get-options, which has this grep:
set tmp [grep $prog "{\[ \t\]\+dg-\[-a-z\]\+\[ \t\]\+.*\[ \t\]\+}" line]
to find directives in the source file, the first part of which are
function names. plugin.exp has a load_lib of target-supports.exp, so
it *should* know about the dg-require-python-h function.
Have a look in the .log for lines that say "ERROR", which can appear if
the syntax of a directive is wrong. Failing that, please post a patch
with the work-in-progress version of the various parts of this that
you're using, so I can see exactly what you're doing, and I can have a
go at debugging it.
Thanks
Dave
> > >
> > > Maybe someone else on the list can see a less hackish way to get
> > > this
> > > to work?
> > >
> > > Let me know if any of the above is unclear.
> > > Dave
> > >
> > >
> > >
> > >
> > >
> > >
> > > > >
> > > > >
> > > > > >
> > > > > > Best,
> > > > > > Eric
> > > > > >
> > > > > > On Tue, Aug 1, 2023 at 1:06 PM David Malcolm
> > > > > > <dmalc...@redhat.com>
> > > > > > wrote:
> > > > > > >
> > > > > > > On Tue, 2023-08-01 at 09:57 -0400, Eric Feng wrote:
> > > > > > > > >
> > > > > > > > > My guess is that you were trying to do it from the
> > > > > > > > > PLUGIN_ANALYZER_INIT
> > > > > > > > > hook rather than from the plugin_init function, but
> > > > > > > > > it's
> > > > > > > > > hard
> > > > > > > > > to be
> > > > > > > > > sure without seeing the code.
> > > > > > > > >
> > > > > > > >
> > > > > > > > Thanks Dave, you are entirely right — I made the
> > > > > > > > mistake of
> > > > > > > > trying to
> > > > > > > > do it from PLUGIN_ANALYZER_INIT hook and not from the
> > > > > > > > plugin_init
> > > > > > > > function. After following your suggestion, the
> > > > > > > > callbacks
> > > > > > > > are
> > > > > > > > getting
> > > > > > > > registered as expected.
> > > > > > >
> > > > > > > Ah, good.
> > > > > > >
> > > > > > > > I submitted a patch to review for this feature
> > > > > > > > on gcc-patches; please let me know if it looks OK.
> > > > > > >
> > > > > > > Thanks Eric; I've posted a reply to your email there, so
> > > > > > > let's
> > > > > > > discuss
> > > > > > > the details there.
> > > > > > >
> > > > > > > Dave
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
