Re: [WIP RFC] analyzer: Add optional trim of the analyzer diagnostics going too deep [PR110543]

[David Malcolm <dmalcolm@redhat.com>]

On Wed, 2023-07-26 at 11:27 +0200, Benjamin Priour wrote:
> On Sat, Jul 22, 2023 at 12:04 AM David Malcolm <dmalcolm@redhat.com>
> wrote:
> 
> > On Fri, 2023-07-21 at 17:35 +0200, Benjamin Priour wrote:
> > > Hi,
> > > 
> > > Upon David's request I've joined the in progress patch to the
> > > below
> > > email.
> > > I hope it makes more sense now.
> > > 
> > > Best,
> > > Benjamin.
> > 
> > Thanks for posting the work-in-progress patch; it makes the idea
> > clearer.
> > 
> > Some thoughts about this:
> > 
> > - I like the idea of defaulting to *not* showing events within
> > system
> > headers, which the patch achieves
> > - I don't like the combination of never/system with maxdepth, in
> > that
> > it seems complicated and I don't think a user is likely to
> > experiment
> > with different depths.
> > - Hence I think it would work better as a simple boolean, perhaps
> >   "-fanalyzer-show-events-in-system-headers"
> >   or somesuch?  It seems like the sort of thing that we want to
> > provide
> > a sensible default for, but have the option of turning off for
> > debugging the analyzer itself, but I don't expect an end-user to
> > touch
> > that option.
> > 
> 
> A boolean sounds good, I will trust your experience with the end-user
> here,
> especially since <maxdepth> and "never" had some overlap, it could
> have
> been confusing.
> 
> 
> > FWIW the patch seems to have been mangled somewhat via email, so I
> > don't have a sense of what the actual output from patched analyzer
> > looks like.  What should we output to the user with -fanalyzer and
> > no
> > other options for the case in PR 110543?  Currently, for
> > https://godbolt.org/z/sb9dM9Gqa trunk emits 12 events, of which
> > probably only this last one is useful:
> > 
> >   (12) dereference of NULL 'a.std::__shared_ptr_access<A,
> > __gnu_cxx::_S_atomic, false, false>::operator->()'
> > 
> > What does the output look like with your patch?
> > 
> 
> The plan with this patch was to get events :
> (1) entry to 'main'
> (2) calling 'std::__shared_ptr_access<A, __gnu_cxx::_S_atomic, false,
> false>::operator->' from 'main'
> (12) dereference of NULL 'a.std::__shared_ptr_access<A,
> __gnu_cxx::_S_atomic, false, false>::operator->()'
> (11) returning to 'main' from 'std::__shared_ptr_access<A,
> __gnu_cxx::_S_atomic, false, false>::operator->'
> 
> This way, we get the entry and exit point to the system headers ( (2)
> and
> (11) ), and the actual injurious event ( (12) ).
> We could however go as you suggest, with an even more succint path
> and only
> keep (1) and (12).

I think we could still have events (11) and (12): what if for call and
return events we consider the location of both the call site and the
called function: we suppress if both are in a system header, but don't
suppress if only one is a system header.  That way by default we'd show
the call into a system header and show the return from the system
header, but we'd suppress all the implementation details within the
system header.

Does that seem like it could work?

Thanks
Dave



> 
> Thanks,
> Benjamin
> 
> 
> > Thanks
> > Dave
> > 
> 
> > 
> > > 
> > > ---------- Forwarded message ---------
> > > From: Benjamin Priour <priour.be@gmail.com>
> > > Date: Tue, Jul 18, 2023 at 3:30 PM
> > > Subject: [RFC] analyzer: Add optional trim of the analyzer
> > > diagnostics
> > > going too deep [PR110543]
> > > To: <gcc-patches@gcc.gnu.org>, David Malcolm
> > > <dmalcolm@redhat.com>
> > > 
> > > 
> > > Hi,
> > > 
> > > I'd like to request comments on a patch I am writing for
> > > PR110543.
> > > The goal of this patch is to reduce the noise of the analyzer
> > > emitted
> > > diagnostics when dealing with
> > > system headers, or simply diagnostic paths that are too long. The
> > > new
> > > option only affects the display
> > > of the diagnostics, but doesn't hinder the actual analysis.
> > > 
> > > I've defaulted the new option to "system", thus preventing the
> > > diagnostic
> > > paths from showing system headers.
> > > "never" corresponds to the pre-patch behavior, whereas you can
> > > also
> > > specify
> > > an unsigned value <maxdepth>
> > > that prevents paths to go deeper than <maxdepth> frames.
> > > 
> > > fanalyzer-trim-diagnostics=
> > > > Common Joined RejectNegative ToLower
> > > > Var(flag_analyzer_trim_diagnostics)
> > > > Init("system")
> > > > -fanalyzer-trim-diagnostics=[never|system|<maxdepth>] Trim
> > > > diagnostics
> > > > path that are too long before emission.
> > > > 
> > > 
> > > Does it sounds reasonable and user-friendly ?
> > > 
> > > Regstrapping was a success against trunk, although one of the
> > > newly
> > > added
> > > test case fails for c++14.
> > > Note that the test case below was done with "never", thus behaves
> > > exactly
> > > as the pre-patch analyzer
> > > on x86_64-linux-gnu.
> > > 
> > > /* { dg-additional-options "-fdiagnostics-plain-output
> > > > -fdiagnostics-path-format=inline-events -fanalyzer-trim-
> > > > diagnostics=never"
> > > > } */
> > > > /* { dg-skip-if "" { c++98_only }  } */
> > > > 
> > > > #include <memory>
> > > > struct A {int x; int y;};
> > > > 
> > > > int main () {
> > > >   std::shared_ptr<A> a;
> > > >   a->x = 4; /* { dg-line deref_a } */
> > > >   /* { dg-warning "dereference of NULL" "" { target *-*-* }
> > > > deref_a
> > > > } */
> > > > 
> > > >   return 0;
> > > > }
> > > > 
> > > > /* { dg-begin-multiline-output "" }
> > > >   'int main()': events 1-2
> > > >     |
> > > >     |
> > > >     +--> 'std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > > <anonymous>
> > > > > ::element_type* std::__shared_ptr_access<_Tp, _Lp,
> > > > > <anonymous>,
> > > > <anonymous> >::operator->() const [with _Tp = A;
> > > > __gnu_cxx::_Lock_policy
> > > > _Lp = __gnu_cxx::_S_atomic; bool <anonymous> = false; bool
> > > > <anonymous> =
> > > > false]': events 3-4
> > > >            |
> > > >            |
> > > >            +--> 'std::__shared_ptr_access<_Tp, _Lp,
> > > > <anonymous>,
> > > > <anonymous> >::element_type* std::__shared_ptr_access<_Tp, _Lp,
> > > > <anonymous>, <anonymous> >::_M_get() const [with _Tp = A;
> > > > __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic; bool
> > > > <anonymous> =
> > > > false; bool <anonymous> = false]': events 5-6
> > > >                   |
> > > >                   |
> > > >                   +--> 'std::__shared_ptr<_Tp,
> > > > _Lp>::element_type*
> > > > std::__shared_ptr<_Tp, _Lp>::get() const [with _Tp = A;
> > > > __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]': events 7-
> > > > 8
> > > >                          |
> > > >                          |
> > > >                   <------+
> > > >                   |
> > > >                 'std::__shared_ptr_access<_Tp, _Lp,
> > > > <anonymous>,
> > > > <anonymous> >::element_type* std::__shared_ptr_access<_Tp, _Lp,
> > > > <anonymous>, <anonymous> >::_M_get() const [with _Tp = A;
> > > > __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic; bool
> > > > <anonymous> =
> > > > false; bool <anonymous> = false]': event 9
> > > >                   |
> > > >                   |
> > > >            <------+
> > > >            |
> > > >          'std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > > <anonymous>
> > > > > ::element_type* std::__shared_ptr_access<_Tp, _Lp,
> > > > > <anonymous>,
> > > > <anonymous> >::operator->() const [with _Tp = A;
> > > > __gnu_cxx::_Lock_policy
> > > > _Lp = __gnu_cxx::_S_atomic; bool <anonymous> = false; bool
> > > > <anonymous> =
> > > > false]': event 10
> > > >            |
> > > >            |
> > > >     <------+
> > > >     |
> > > >   'int main()': events 11-12
> > > >     |
> > > >     |
> > > >    { dg-end-multiline-output "" } */
> > > > 
> > > 
> > > 
> > > The first events "'int main()': events 1-2" vary in c++14 (get
> > > events
> > > 1-3).
> > > 
> > > > 
> > > > // c++14 with fully detailed output
> > > >   ‘int main()’: events 1-3
> > > >     |
> > > >     |    8 | int main () {
> > > >     |      |     ^~~~
> > > >     |      |     |
> > > >     |      |     (1) entry to ‘main’
> > > >     |    9 |   std::shared_ptr<A> a;
> > > >     |      |                      ~
> > > >     |      |                      |
> > > >     |      |                      (2)
> > > > ‘a.std::shared_ptr<A>::<anonymous>.std::__shared_ptr<A,
> > > > __gnu_cxx::_S_atomic>::_M_ptr’ is NULL
> > > >     |   10 |   a->x = 4; /* { dg-line deref_a } */
> > > >     |      |    ~~
> > > >     |      |    |
> > > >     |      |    (3) calling ‘std::__shared_ptr_access<A,
> > > > __gnu_cxx::_S_atomic, false, false>::operator->’ from ‘main’
> > > > 
> > > 
> > > whereas c++17 and posterior give
> > > 
> > > > // c++17 with fully detailed output
> > > > 
> > > // ./xg++ -fanalyzer
> > > >  ../../gcc/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-
> > > > diagnostics-never.C
> > > >  -B. -shared-libgcc -fanalyzer-trim-diagnostics=never -
> > > > std=c++17
> > > > 
> > >   ‘int main()’: events 1-2
> > > >     |
> > > >     |    8 | int main () {
> > > >     |      |     ^~~~
> > > >     |      |     |
> > > >     |      |     (1) entry to ‘main’
> > > >     |    9 |   std::shared_ptr<A> a;
> > > >     |   10 |   a->x = 4; /* { dg-line deref_a } */
> > > >     |      |    ~~
> > > >     |      |    |
> > > >     |      |    (2) calling ‘std::__shared_ptr_access<A,
> > > > __gnu_cxx::_S_atomic, false, false>::operator->’ from ‘main’
> > > > 
> > > 
> > > Is there a way to make dg-multiline-output check for a regex ? Or
> > > would
> > > checking the multiline-output only for c++17 and c++20 be
> > > acceptable
> > > ?
> > > This divergence results from two slightly different IPA:
> > > 
> > > // c++14 -fdump-ipa-analyzer
> > > > // std::shared_ptr<A> a; becomes
> > > > a.D.29392._M_ptr = 0B;
> > > > a.D.29392._M_refcount._M_pi = 0B;
> > > > 
> > > 
> > > whereas in c++17
> > > 
> > > > // c++17 -fdump-ipa-analyzer
> > > > // std::shared_ptr<A> a; becomes
> > > > a = {};
> > > > 
> > > 
> > > I know shared_ptr limited support is a coincidence more than a
> > > feature, but
> > > maybe there is still a way to make the above test case work ?
> > > Otherwise, I'd fallback to a supported system function. If you
> > > have
> > > any
> > > that you fancy, do tell me.
> > > 
> > > Thanks,
> > > Benjamin.
> > > 
> > > ---
> > >  gcc/analyzer/analyzer.cc                      |   2 +-
> > >  gcc/analyzer/analyzer.h                       |   1 +
> > >  gcc/analyzer/analyzer.opt                     |   4 +
> > >  gcc/analyzer/diagnostic-manager.cc            | 132
> > > ++++++++++++++++++
> > >  gcc/analyzer/diagnostic-manager.h             |   7 +
> > >  .../analyzer/fanalyzer-trim-diagnostics-0.C   |  19 +++
> > >  .../analyzer/fanalyzer-trim-diagnostics-1.C   |  28 ++++
> > >  .../analyzer/fanalyzer-trim-diagnostics-2.C   |  44 ++++++
> > >  .../fanalyzer-trim-diagnostics-default.C      |  21 +++
> > >  .../fanalyzer-trim-diagnostics-never.C        |  44 ++++++
> > >  .../fanalyzer-trim-diagnostics-system.C       |  19 +++
> > >  11 files changed, 320 insertions(+), 1 deletion(-)
> > >  create mode 100644
> > > gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-0.C
> > >  create mode 100644
> > > gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-1.C
> > >  create mode 100644
> > > gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-2.C
> > >  create mode 100644
> > > gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > default.C
> > >  create mode 100644
> > > gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-never.C
> > >  create mode 100644
> > > gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-system.C
> > > 
> > > diff --git a/gcc/analyzer/analyzer.cc b/gcc/analyzer/analyzer.cc
> > > index 5091fb7a583..b27d8e359db 100644
> > > --- a/gcc/analyzer/analyzer.cc
> > > +++ b/gcc/analyzer/analyzer.cc
> > > @@ -274,7 +274,7 @@ is_named_call_p (const_tree fndecl, const
> > > char
> > > *funcname)
> > >     Compare with cp/typeck.cc: decl_in_std_namespace_p, but this
> > > doesn't
> > >     rely on being the C++ FE (or handle inline namespaces inside
> > > of
> > > std).
> > >  */
> > > 
> > > -static inline bool
> > > +bool
> > >  is_std_function_p (const_tree fndecl)
> > >  {
> > >    tree name_decl = DECL_NAME (fndecl);
> > > diff --git a/gcc/analyzer/analyzer.h b/gcc/analyzer/analyzer.h
> > > index 579517c23e6..31597079153 100644
> > > --- a/gcc/analyzer/analyzer.h
> > > +++ b/gcc/analyzer/analyzer.h
> > > @@ -386,6 +386,7 @@ extern bool is_special_named_call_p (const
> > > gcall
> > > *call,
> > > const char *funcname,
> > >  extern bool is_named_call_p (const_tree fndecl, const char
> > > *funcname);
> > >  extern bool is_named_call_p (const_tree fndecl, const char
> > > *funcname,
> > >       const gcall *call, unsigned int num_args);
> > > +extern bool is_std_function_p (const_tree fndecl);
> > >  extern bool is_std_named_call_p (const_tree fndecl, const char
> > > *funcname);
> > >  extern bool is_std_named_call_p (const_tree fndecl, const char
> > > *funcname,
> > >   const gcall *call, unsigned int num_args);
> > > diff --git a/gcc/analyzer/analyzer.opt
> > > b/gcc/analyzer/analyzer.opt
> > > index 2760aaa8151..78ff2c07483 100644
> > > --- a/gcc/analyzer/analyzer.opt
> > > +++ b/gcc/analyzer/analyzer.opt
> > > @@ -362,4 +362,8 @@ fdump-analyzer-untracked
> > >  Common RejectNegative Var(flag_dump_analyzer_untracked)
> > >  Emit custom warnings with internal details intended for analyzer
> > > developers.
> > > 
> > > +fanalyzer-trim-diagnostics=
> > > +Common Joined RejectNegative ToLower
> > > Var(flag_analyzer_trim_diagnostics)
> > > Init("system")
> > > +-fanalyzer-trim-diagnostics=[never|system|<maxdepth>] Trim
> > > diagnostics
> > > path that are too long before emission.
> > > +
> > >  ; This comment is to ensure we retain the blank line above.
> > > diff --git a/gcc/analyzer/diagnostic-manager.cc
> > > b/gcc/analyzer/diagnostic-manager.cc
> > > index cfca305d552..d946ad5bac7 100644
> > > --- a/gcc/analyzer/diagnostic-manager.cc
> > > +++ b/gcc/analyzer/diagnostic-manager.cc
> > > @@ -20,9 +20,11 @@ along with GCC; see the file COPYING3.  If not
> > > see
> > > 
> > >  #include "config.h"
> > >  #define INCLUDE_MEMORY
> > > +#define INCLUDE_VECTOR
> > >  #include "system.h"
> > >  #include "coretypes.h"
> > >  #include "tree.h"
> > > +#include "input.h"
> > >  #include "pretty-print.h"
> > >  #include "gcc-rich-location.h"
> > >  #include "gimple-pretty-print.h"
> > > @@ -60,6 +62,37 @@ along with GCC; see the file COPYING3.  If not
> > > see
> > > 
> > >  #if ENABLE_ANALYZER
> > > 
> > > +/* Return positive value of fanalyzer-trim-diagnostics if a
> > > depth
> > > was given
> > > +  or a negative value otherwise.  */
> > > +
> > > +long trim_diagnostics_depth ()
> > > +{
> > > +  if (trim_diagnostics_system_p () ||  trim_diagnostics_never_p
> > > ())
> > > +    return -1;
> > > +
> > > +  char *end = NULL;
> > > +  long depth = strtol (flag_analyzer_trim_diagnostics, &end,
> > > 10);
> > > +  gcc_assert (end == NULL || *end == '\0');
> > > +  gcc_assert (!(end == flag_analyzer_trim_diagnostics && depth
> > > ==
> > > 0));
> > > +  return depth;
> > > +}
> > > +
> > > +/* Return true if fanalyzer-trim-diagnostics is set to
> > > "system".  */
> > > +
> > > +bool trim_diagnostics_system_p ()
> > > +{
> > > +  int len = strlen (flag_analyzer_trim_diagnostics);
> > > +  return len == 6 && strcmp (flag_analyzer_trim_diagnostics,
> > > "system") ==
> > > 0;
> > > +}
> > > +
> > > +/* Return true if fanalyzer-trim-diagnostics is set to "never". 
> > > */
> > > +
> > > +bool trim_diagnostics_never_p ()
> > > +{
> > > +  int len = strlen (flag_analyzer_trim_diagnostics);
> > > +  return len == 5 && strcmp (flag_analyzer_trim_diagnostics,
> > > "never") == 0;
> > > +}
> > > +
> > >  namespace ana {
> > > 
> > >  class feasible_worklist;
> > > @@ -2281,6 +2314,8 @@ diagnostic_manager::prune_path
> > > (checker_path
> > > *path,
> > >    path->maybe_log (get_logger (), "path");
> > >    prune_for_sm_diagnostic (path, sm, sval, state);
> > >    prune_interproc_events (path);
> > > +  if (! trim_diagnostics_never_p ())
> > > +    trim_diagnostic_path (path);
> > >    consolidate_conditions (path);
> > >    finish_pruning (path);
> > >    path->maybe_log (get_logger (), "pruned");
> > > @@ -2667,6 +2702,103 @@
> > > diagnostic_manager::prune_interproc_events
> > > (checker_path *path) const
> > >    while (changed);
> > >  }
> > > 
> > > +void
> > > +diagnostic_manager::trim_diagnostic_path (checker_path *path)
> > > const
> > > +{
> > > +  if (trim_diagnostics_system_p ())
> > > +    prune_system_headers (path);
> > > +  else
> > > +    prune_events_too_deep (path);
> > > +}
> > > +
> > > +/* Remove everything within ]callsite, IDX].  */
> > > +static void
> > > +prune_within_frame (checker_path *path, int &idx)
> > > +{
> > > +  int nesting = 1;
> > > +  while (idx >= 0 && nesting != 0)
> > > +    {
> > > +      if (path->get_checker_event (idx)->is_call_p ())
> > > +        nesting--;
> > > +      else if (path->get_checker_event (idx)->is_return_p ())
> > > +        nesting++;
> > > +
> > > +      path->delete_event (idx--);
> > > +    }
> > > +}
> > > +
> > > +void
> > > +diagnostic_manager::prune_system_headers (checker_path *path)
> > > const
> > > +{
> > > +  int idx = (signed)path->num_events () - 1;
> > > +  while (idx >= 0)
> > > +    {
> > > +      const checker_event *event = path->get_checker_event
> > > (idx);
> > > +      /* Prune everything between [..., system call, (...),
> > > system
> > > return,
> > > ...].  */
> > > +      if (event->is_return_p ()
> > > +          && in_system_header_at (event->get_location ()))
> > > +      {
> > > +        int ret_idx = idx;
> > > +        prune_within_frame (path, idx);
> > > +
> > > +        if (get_logger ())
> > > +        {
> > > +          label_text desc
> > > +            (path->get_checker_event (idx)->get_desc (false));
> > > +          log ("filtering event %i-%i:"
> > > +              " system header event: %s",
> > > +              idx, ret_idx, desc.get ());
> > > +        }
> > > +        // delete callsite
> > > +        if (idx >= 0)
> > > +          path->delete_event (idx);
> > > +      }
> > > +
> > > +      idx--;
> > > +    }
> > > +}
> > > +
> > > +void
> > > +diagnostic_manager::prune_events_too_deep (checker_path *path)
> > > const
> > > +{
> > > +  long depth = 0;
> > > +  long maxdepth = trim_diagnostics_depth ();
> > > +  gcc_assert (maxdepth >= 0);
> > > +  int idx = (signed)path->num_events () - 1;
> > > +  if (idx >= 0)
> > > +  {
> > > +    depth = path->get_checker_event (0)->get_stack_depth ();
> > > +    maxdepth += depth;
> > > +  }
> > > +
> > > +  while (idx >= 0)
> > > +    {
> > > +      const checker_event *event = path->get_checker_event
> > > (idx);
> > > +      /* Prune everything between [..., call too deep, (...),
> > > return
> > > too
> > > deep, ...].  */
> > > +      if (event->is_return_p ()
> > > +          && event->get_stack_depth () > maxdepth)
> > > +      {
> > > +        int ret_idx = idx;
> > > +        prune_within_frame (path, idx);
> > > +
> > > +        if (get_logger ())
> > > +        {
> > > +          label_text desc
> > > +            (path->get_checker_event (idx)->get_desc (false));
> > > +          log ("filtering event %i-%i:"
> > > +              " event too deep: %s",
> > > +              idx, ret_idx, desc.get ());
> > > +        }
> > > +        // delete callsite
> > > +        if (idx >= 0)
> > > +          path->delete_event (idx);
> > > +      }
> > > +
> > > +      idx--;
> > > +    }
> > > +
> > > +}
> > > +
> > >  /* Return true iff event IDX within PATH is on the same line as
> > > REF_EXP_LOC.  */
> > > 
> > >  static bool
> > > diff --git a/gcc/analyzer/diagnostic-manager.h
> > > b/gcc/analyzer/diagnostic-manager.h
> > > index 9b3e903fc5d..9afef0975be 100644
> > > --- a/gcc/analyzer/diagnostic-manager.h
> > > +++ b/gcc/analyzer/diagnostic-manager.h
> > > @@ -21,6 +21,10 @@ along with GCC; see the file COPYING3.  If not
> > > see
> > >  #ifndef GCC_ANALYZER_DIAGNOSTIC_MANAGER_H
> > >  #define GCC_ANALYZER_DIAGNOSTIC_MANAGER_H
> > > 
> > > +long trim_diagnostics_depth ();
> > > +bool trim_diagnostics_system_p ();
> > > +bool trim_diagnostics_never_p ();
> > > +
> > >  namespace ana {
> > > 
> > >  class epath_finder;
> > > @@ -180,6 +184,9 @@ private:
> > >   state_machine::state_t state) const;
> > >    void update_for_unsuitable_sm_exprs (tree *expr) const;
> > >    void prune_interproc_events (checker_path *path) const;
> > > +  void trim_diagnostic_path (checker_path *path) const;
> > > +  void prune_system_headers (checker_path *path) const;
> > > +  void prune_events_too_deep (checker_path *path) const;
> > >    void consolidate_conditions (checker_path *path) const;
> > >    void finish_pruning (checker_path *path) const;
> > > 
> > > diff --git a/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-
> > > diagnostics-0.C
> > > b/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-0.C
> > > new file mode 100644
> > > index 00000000000..ddf39ed1690
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > 0.C
> > > @@ -0,0 +1,19 @@
> > > +/* { dg-additional-options "-fdiagnostics-plain-output
> > > -fdiagnostics-path-format=inline-events -fanalyzer-trim-
> > > diagnostics=0" } */
> > > +/* { dg-skip-if "" { c++98_only }  } */
> > > +
> > > +#include <memory>
> > > +
> > > +struct A {int x; int y;};
> > > +
> > > +int main () {
> > > +  std::shared_ptr<A> a;
> > > +  a->x = 4; /* { dg-line deref_a } */
> > > +  /* { dg-warning "dereference of NULL" "" { target *-*-* }
> > > deref_a
> > > } */
> > > +
> > > +  return 0;
> > > +}
> > > +/* { dg-begin-multiline-output "" }
> > > +  'int main()': events 1-2
> > > +    |
> > > +    |
> > > +   { dg-end-multiline-output "" } */
> > > \ No newline at end of file
> > > diff --git a/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-
> > > diagnostics-1.C
> > > b/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-1.C
> > > new file mode 100644
> > > index 00000000000..83a132078a1
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > 1.C
> > > @@ -0,0 +1,28 @@
> > > +/* { dg-additional-options "-fdiagnostics-plain-output
> > > -fdiagnostics-path-format=inline-events -fanalyzer-trim-
> > > diagnostics=1" } */
> > > +/* { dg-skip-if "" { c++98_only }  } */
> > > +
> > > +#include <memory>
> > > +
> > > +struct A {int x; int y;};
> > > +
> > > +int main () {
> > > +  std::shared_ptr<A> a;
> > > +  a->x = 4; /* { dg-line deref_a } */
> > > +  /* { dg-warning "dereference of NULL" "" { target *-*-* }
> > > deref_a
> > > } */
> > > +
> > > +  return 0;
> > > +}
> > > +
> > > +/* { dg-begin-multiline-output "" }
> > > +  'int main()': events 1-2
> > > +    |
> > > +    |
> > > +    +--> 'std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous>
> > > > ::element_type* std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous> >::operator->() const [with _Tp = A;
> > > __gnu_cxx::_Lock_policy
> > > _Lp = __gnu_cxx::_S_atomic; bool <anonymous> = false; bool
> > > <anonymous> =
> > > false]': event 3
> > > +           |
> > > +           |
> > > +    <------+
> > > +    |
> > > +  'int main()': events 4-5
> > > +    |
> > > +    |
> > > +   { dg-end-multiline-output "" } */
> > > \ No newline at end of file
> > > diff --git a/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-
> > > diagnostics-2.C
> > > b/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-2.C
> > > new file mode 100644
> > > index 00000000000..cf065929ec9
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > 2.C
> > > @@ -0,0 +1,44 @@
> > > +/* { dg-additional-options "-fdiagnostics-plain-output
> > > -fdiagnostics-path-format=inline-events -fanalyzer-trim-
> > > diagnostics=2" } */
> > > +/* { dg-skip-if "" { c++98_only }  } */
> > > +
> > > +#include <memory>
> > > +
> > > +struct A {int x; int y;};
> > > +
> > > +int main () {
> > > +  std::shared_ptr<A> a;
> > > +  a->x = 4; /* { dg-line deref_a } */
> > > +  /* { dg-warning "dereference of NULL" "" { target *-*-* }
> > > deref_a
> > > } */
> > > +
> > > +  return 0;
> > > +}
> > > +
> > > +/* { dg-begin-multiline-output "" }
> > > +  'int main()': events 1-2
> > > +    |
> > > +    |
> > > +    +--> 'std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous>
> > > > ::element_type* std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous> >::operator->() const [with _Tp = A;
> > > __gnu_cxx::_Lock_policy
> > > _Lp = __gnu_cxx::_S_atomic; bool <anonymous> = false; bool
> > > <anonymous> =
> > > false]': events 3-4
> > > +           |
> > > +           |
> > > +           +--> 'std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous> >::element_type* std::__shared_ptr_access<_Tp, _Lp,
> > > <anonymous>, <anonymous> >::_M_get() const [with _Tp = A;
> > > __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic; bool
> > > <anonymous>
> > > =
> > > false; bool <anonymous> = false]': events 5-6
> > > +                  |
> > > +                  |
> > > +                  +--> 'std::__shared_ptr<_Tp,
> > > _Lp>::element_type*
> > > std::__shared_ptr<_Tp, _Lp>::get() const [with _Tp = A;
> > > __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]': events 7-8
> > > +                         |
> > > +                         |
> > > +                  <------+
> > > +                  |
> > > +                'std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous> >::element_type* std::__shared_ptr_access<_Tp, _Lp,
> > > <anonymous>, <anonymous> >::_M_get() const [with _Tp = A;
> > > __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic; bool
> > > <anonymous>
> > > =
> > > false; bool <anonymous> = false]': event 9
> > > +                  |
> > > +                  |
> > > +           <------+
> > > +           |
> > > +         'std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous>
> > > > ::element_type* std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous> >::operator->() const [with _Tp = A;
> > > __gnu_cxx::_Lock_policy
> > > _Lp = __gnu_cxx::_S_atomic; bool <anonymous> = false; bool
> > > <anonymous> =
> > > false]': event 10
> > > +           |
> > > +           |
> > > +    <------+
> > > +    |
> > > +  'int main()': events 11-12
> > > +    |
> > > +    |
> > > +   { dg-end-multiline-output "" } */
> > > \ No newline at end of file
> > > diff --git
> > > a/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > default.C
> > > b/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > default.C
> > > new file mode 100644
> > > index 00000000000..fc271309d4e
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > default.C
> > > @@ -0,0 +1,21 @@
> > > +/* { dg-additional-options "-O0 -fdiagnostics-plain-output
> > > -fdiagnostics-path-format=inline-events" } */
> > > +/* { dg-skip-if "" { c++98_only }  } */
> > > +
> > > +// Must behave like -fanalyzer-trim-diagnostics=system
> > > +
> > > +#include <memory>
> > > +
> > > +struct A {int x; int y;};
> > > +
> > > +int main () {
> > > +  std::shared_ptr<A> a;
> > > +  a->x = 4; /* { dg-line deref_a } */
> > > +  /* { dg-warning "dereference of NULL" "" { target *-*-* }
> > > deref_a
> > > } */
> > > +
> > > +  return 0;
> > > +}
> > > +/* { dg-begin-multiline-output "" }
> > > +  'int main()': events 1-2
> > > +    |
> > > +    |
> > > +   { dg-end-multiline-output "" } */
> > > \ No newline at end of file
> > > diff --git
> > > a/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > never.C
> > > b/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > never.C
> > > new file mode 100644
> > > index 00000000000..a69416608da
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > never.C
> > > @@ -0,0 +1,44 @@
> > > +/* { dg-additional-options "-fdiagnostics-plain-output
> > > -fdiagnostics-path-format=inline-events -fanalyzer-trim-
> > > diagnostics=never"
> > > } */
> > > +/* { dg-skip-if "" { c++98_only }  } */
> > > +
> > > +#include <memory>
> > > +
> > > +struct A {int x; int y;};
> > > +
> > > +int main () {
> > > +  std::shared_ptr<A> a;
> > > +  a->x = 4; /* { dg-line deref_a } */
> > > +  /* { dg-warning "dereference of NULL" "" { target *-*-* }
> > > deref_a
> > > } */
> > > +
> > > +  return 0;
> > > +}
> > > +
> > > +/* { dg-begin-multiline-output "" }
> > > +  'int main()': events 1-2
> > > +    |
> > > +    |
> > > +    +--> 'std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous>
> > > > ::element_type* std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous> >::operator->() const [with _Tp = A;
> > > __gnu_cxx::_Lock_policy
> > > _Lp = __gnu_cxx::_S_atomic; bool <anonymous> = false; bool
> > > <anonymous> =
> > > false]': events 3-4
> > > +           |
> > > +           |
> > > +           +--> 'std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous> >::element_type* std::__shared_ptr_access<_Tp, _Lp,
> > > <anonymous>, <anonymous> >::_M_get() const [with _Tp = A;
> > > __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic; bool
> > > <anonymous>
> > > =
> > > false; bool <anonymous> = false]': events 5-6
> > > +                  |
> > > +                  |
> > > +                  +--> 'std::__shared_ptr<_Tp,
> > > _Lp>::element_type*
> > > std::__shared_ptr<_Tp, _Lp>::get() const [with _Tp = A;
> > > __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]': events 7-8
> > > +                         |
> > > +                         |
> > > +                  <------+
> > > +                  |
> > > +                'std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous> >::element_type* std::__shared_ptr_access<_Tp, _Lp,
> > > <anonymous>, <anonymous> >::_M_get() const [with _Tp = A;
> > > __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic; bool
> > > <anonymous>
> > > =
> > > false; bool <anonymous> = false]': event 9
> > > +                  |
> > > +                  |
> > > +           <------+
> > > +           |
> > > +         'std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous>
> > > > ::element_type* std::__shared_ptr_access<_Tp, _Lp, <anonymous>,
> > > <anonymous> >::operator->() const [with _Tp = A;
> > > __gnu_cxx::_Lock_policy
> > > _Lp = __gnu_cxx::_S_atomic; bool <anonymous> = false; bool
> > > <anonymous> =
> > > false]': event 10
> > > +           |
> > > +           |
> > > +    <------+
> > > +    |
> > > +  'int main()': events 11-12
> > > +    |
> > > +    |
> > > +   { dg-end-multiline-output "" } */
> > > \ No newline at end of file
> > > diff --git
> > > a/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > system.C
> > > b/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > system.C
> > > new file mode 100644
> > > index 00000000000..22fadc84e75
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/analyzer/fanalyzer-trim-diagnostics-
> > > system.C
> > > @@ -0,0 +1,19 @@
> > > +/* { dg-additional-options "-fdiagnostics-plain-output
> > > -fdiagnostics-path-format=inline-events -fanalyzer-trim-
> > > diagnostics=system"
> > > } */
> > > +/* { dg-skip-if "" { c++98_only }  } */
> > > +
> > > +#include <memory>
> > > +
> > > +struct A {int x; int y;};
> > > +
> > > +int main () {
> > > +  std::shared_ptr<A> a;
> > > +  a->x = 4; /* { dg-line deref_a } */
> > > +  /* { dg-warning "dereference of NULL" "" { target *-*-* }
> > > deref_a
> > > } */
> > > +
> > > +  return 0;
> > > +}
> > > +/* { dg-begin-multiline-output "" }
> > > +  'int main()': events 1-2
> > > +    |
> > > +    |
> > > +   { dg-end-multiline-output "" } */
> > > \ No newline at end of file
> > 
> >