Re: [PATCH] Support running the selftests under valgrind

[David Malcolm <dmalcolm at redhat dot com>]

On Fri, 2016-07-08 at 22:55 -0700, Andrew Pinski wrote:
> On Fri, Jul 8, 2016 at 12:46 PM, David Malcolm <dmalcolm@redhat.com>
> wrote:
> > This patch adds a new phony target to gcc/Makefile.in to make it
> > easy
> > to run the selftests under valgrind, via "make selftest-valgrind".
> > This phony target isn't a dependency of anything; it's purely for
> > convenience (it takes about 4-5 seconds on my box).
> > 
> > Doing so uncovered a few leaks in the selftest suite, which the
> > patch also fixes, so that it runs cleanly under valgrind (on
> > x86_64-pc-linux-gnu, configured with --enable-valgrind-annotations,
> > at least).
> > 
> > Successfully bootstrapped&regrtested on x86_64-pc-linux-gnu.
> > Manually verified that the valgrind output is "clean" on
> > x86_64-pc-linux-gnu [1].
> > 
> > OK for trunk?
> 
> I think this is a good idea.  I assume this not turned on by default.
> valgrind is still not fully working on aarch64 :).

Correct; that's what I was trying to express by saying it isn't a
dependency of anything.  I wouldn't want to make that a requirement.

FWIW, it's very useful when writing new selftests; I was using it when
writing the string literal location patch I just posted.  It caught a
memory leak when tracking string concatenation, for the case of
concatenating a string that's fully <= LINE_MAP_MAX_LOCATION_WITH_COLS
with a string that is at least partly beyond that boundary.  This leak
would have been hard to find using our traditional test approach. (the
version of the string literal patch that I posted is clean under "make
selftest-valgrind").

> Thanks,
> Andrew
> 
> > 
> > [1]:
> > 
> >  HEAP SUMMARY:
> >      in use at exit: 1,203,983 bytes in 2,114 blocks
> >    total heap usage: 4,545 allocs, 2,431 frees, 3,212,841 bytes
> > allocated
> > 
> >  LEAK SUMMARY:
> >     definitely lost: 0 bytes in 0 blocks
> >     indirectly lost: 0 bytes in 0 blocks
> >       possibly lost: 0 bytes in 0 blocks
> >     still reachable: 1,203,983 bytes in 2,114 blocks
> >          suppressed: 0 bytes in 0 blocks
> >  Reachable blocks (those to which a pointer was found) are not
> > shown.
> >  To see them, rerun with: --leak-check=full --show-leak-kinds=all
> > 
> >  For counts of detected and suppressed errors, rerun with: -v
> >  ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2)
> > 
> > gcc/ChangeLog:
> >         * Makefile.in (selftest-valgrind): New phony target.
> >         * function-tests.c (selftest::build_cfg): Delete pass
> > instances
> >         created by the test.
> >         (selftest::convert_to_ssa): Likewise.
> >         (selftest::test_expansion_to_rtl): Likewise.
> >         * tree-cfg.c (selftest::test_linear_chain): Release
> > dominator
> >         vectors.
> >         (selftest::test_diamond): Likewise.
> > ---
> >  gcc/Makefile.in      | 6 ++++++
> >  gcc/function-tests.c | 4 ++++
> >  gcc/tree-cfg.c       | 6 ++++++
> >  3 files changed, 16 insertions(+)
> > 
> > diff --git a/gcc/Makefile.in b/gcc/Makefile.in
> > index 5e7422d..1a4b5d7 100644
> > --- a/gcc/Makefile.in
> > +++ b/gcc/Makefile.in
> > @@ -1869,6 +1869,12 @@ s-selftest: $(GCC_PASSES) cc1$(exeext) stmp
> > -int-hdrs
> >  selftest-gdb: $(GCC_PASSES) cc1$(exeext) stmp-int-hdrs
> >         $(GCC_FOR_TARGET) -xc -S -c /dev/null -fself-test -wrapper
> > gdb,--args
> > 
> > +# Convenience method for running selftests under valgrind:
> > +.PHONY: selftest-valgrind
> > +selftest-valgrind: $(GCC_PASSES) cc1$(exeext) stmp-int-hdrs
> > +       $(GCC_FOR_TARGET) -xc -S -c /dev/null -fself-test \
> > +         -wrapper valgrind,--leak-check=full
> > +
> >  # Recompile all the language-independent object files.
> >  # This is used only if the user explicitly asks for it.
> >  compilations: $(BACKEND)
> > diff --git a/gcc/function-tests.c b/gcc/function-tests.c
> > index c8188e7..edd355f 100644
> > --- a/gcc/function-tests.c
> > +++ b/gcc/function-tests.c
> > @@ -296,6 +296,7 @@ build_cfg (tree fndecl)
> >    push_cfun (fun);
> >    lower_cf_pass->execute (fun);
> >    pop_cfun ();
> > +  delete lower_cf_pass;
> > 
> >    /* We can now convert to CFG form; for our trivial test function
> > this
> >       gives us:
> > @@ -310,6 +311,7 @@ build_cfg (tree fndecl)
> >    push_cfun (fun);
> >    build_cfg_pass->execute (fun);
> >    pop_cfun ();
> > +  delete build_cfg_pass;
> >  }
> > 
> >  /* Convert a gimple+CFG function to SSA form.  */
> > @@ -325,6 +327,7 @@ convert_to_ssa (tree fndecl)
> >    push_cfun (fun);
> >    build_ssa_pass->execute (fun);
> >    pop_cfun ();
> > +  delete build_ssa_pass;
> >  }
> > 
> >  /* Assuming we have a simple 3-block CFG like this:
> > @@ -594,6 +597,7 @@ test_expansion_to_rtl ()
> >    init_function_start (fndecl);
> >    expand_pass->execute (fun);
> >    pop_cfun ();
> > +  delete expand_pass;
> > 
> >    /* On x86_64, I get this:
> >         (note 3 1 2 2 [bb 2] NOTE_INSN_BASIC_BLOCK)
> > diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
> > index 0fac49c..6d69435 100644
> > --- a/gcc/tree-cfg.c
> > +++ b/gcc/tree-cfg.c
> > @@ -9276,6 +9276,7 @@ test_linear_chain ()
> >    ASSERT_EQ (1, dom_by_b.length ());
> >    ASSERT_EQ (bb_c, dom_by_b[0]);
> >    free_dominance_info (CDI_DOMINATORS);
> > +  dom_by_b.release ();
> > 
> >    /* Similarly for post-dominance: each BB in our chain is post
> > -dominated
> >       by the one after it.  */
> > @@ -9286,6 +9287,7 @@ test_linear_chain ()
> >    ASSERT_EQ (1, postdom_by_b.length ());
> >    ASSERT_EQ (bb_a, postdom_by_b[0]);
> >    free_dominance_info (CDI_POST_DOMINATORS);
> > +  postdom_by_b.release ();
> > 
> >    pop_cfun ();
> >  }
> > @@ -9346,8 +9348,10 @@ test_diamond ()
> >    ASSERT_EQ (bb_a, get_immediate_dominator (CDI_DOMINATORS,
> > bb_d));
> >    vec<basic_block> dom_by_a = get_dominated_by (CDI_DOMINATORS,
> > bb_a);
> >    ASSERT_EQ (3, dom_by_a.length ()); /* B, C, D, in some order. 
> >  */
> > +  dom_by_a.release ();
> >    vec<basic_block> dom_by_b = get_dominated_by (CDI_DOMINATORS,
> > bb_b);
> >    ASSERT_EQ (0, dom_by_b.length ());
> > +  dom_by_b.release ();
> >    free_dominance_info (CDI_DOMINATORS);
> > 
> >    /* Similarly for post-dominance.  */
> > @@ -9357,8 +9361,10 @@ test_diamond ()
> >    ASSERT_EQ (bb_d, get_immediate_dominator (CDI_POST_DOMINATORS,
> > bb_c));
> >    vec<basic_block> postdom_by_d = get_dominated_by
> > (CDI_POST_DOMINATORS, bb_d);
> >    ASSERT_EQ (3, postdom_by_d.length ()); /* A, B, C in some order.
> >   */
> > +  postdom_by_d.release ();
> >    vec<basic_block> postdom_by_b = get_dominated_by
> > (CDI_POST_DOMINATORS, bb_b);
> >    ASSERT_EQ (0, postdom_by_b.length ());
> > +  postdom_by_b.release ();
> >    free_dominance_info (CDI_POST_DOMINATORS);
> > 
> >    pop_cfun ();
> > --
> > 1.8.5.3
> >