Re: [PATCH] Make Warray-bounds alias to Warray-bounds= [PR107787]

[Richard Biener <richard.guenther@gmail.com>]

On Thu, Nov 24, 2022 at 4:27 PM Iskander Shakirzyanov
<iskander@ispras.ru> wrote:
>
> How did you test the patch? If you bootstrapped it and ran the
> testsuite then it's OK.
>
> Yes, i ran testsuite and  bootstrapped and everything seemed OK, but i missed fail of tests gcc.dg/Warray-bounds-34.c and gcc.dg/Warray-bounds-43.c, so Franz is right. After that I fixed the regexps in dg directives and now everything seems OK.
>
> I'm pretty sure the testsuite will have regressions, as I have a very similar patch lying around that needs these testsuite changes.
>
> You are right, thank you. I missed this, attaching corrected version of patch.
>
> This also shows nicely why I don't like warnings with levels, what if I want -Werror=array-bounds=2 + -Warray-bounds=1?
>
> I completely agree with you, because I also thought about using -Werror=opt=X + -Wopt=Y, this functionality looks useful. As I know, gcc, while parsing an option with the same OPT,  overwrites the old config of OPT.
>
> Because I think at least -Wuse-after-free= and Wattributes= have the same problem.
>
> Yes, looks like this, probably should be fixed too.
>
> BTW, is the duplicated warning description "Warn if an array is accessed out of bounds." needed or not with Alias()?
>
> According to other examples in common.opt, duplicated description is not necessary, you are right.
>
> I've attached my patch, feel free to integrate the testsuite changes.
>
> Thanks, but it seems to me that duplicating existing tests seems redundant to test functionality of -Werror=array-bounds=X.
>
>
> From bf047e36392dab138db10be2ec257d08c376ada5 Mon Sep 17 00:00:00 2001
> From: Iskander Shakirzyanov <iskander@ispras.ru>
> Date: Thu, 24 Nov 2022 14:26:59 +0000
> Subject: [PATCH] Make Warray-bounds alias to Warray-bounds= [PR107787]
>
> According to documentation the -Werror= option makes the specified warning
> into an error and also automatically implies this option. Then it seems that
> the behavior of the compiler when specifying -Werror=array-bounds=X should be
> the same as specifying "-Werror=array-bounds -Warray-bounds=X", so we expect to
> receive array-bounds pass triggers and they must be processed as errors.
> In practice, we observe that the array-bounds pass is indeed called, but
> its responses are processed as warnings, not errors.
> As I understand, this happens because Warray-bounds and Warray-bounds= are
> declared as 2 different options in common.opt, so when
> diagnostic_classify_diagnostic() is called, DK_ERROR is set for
> the Warray-bounds= option, but in diagnostic_report_diagnostic() through
> warning_at() passes opt_index of Warray-bounds, so information about
> DK_ERROR is lost. Fixed by using Alias() in declaration of
> Warray-bounds (similarly as in Wattribute-alias etc.)

OK if this passed bootstrap & regtest.

Thanks,
Richard.

> PR driver/107787
>
> Co-authored-by: Franz Sirl <Franz.Sirl-kernel@lauterbach.com>
>
> gcc/ChangeLog:
>
> * common.opt (Warray-bounds): Turn into alias to
> -Warray-bounds=1.
> * builtins.cc (warn_array_bounds): Use OPT_Warray_bounds_
> instead of OPT_Warray_bounds.
> * diagnostic-spec.cc: Likewise.
> * gimple-array-bounds.cc: Likewise.
> * gimple-ssa-warn-restrict.cc: Likewise.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/Warray-bounds-34.c: Correct the regular
> expression for -Warray-bounds=.
> * gcc.dg/Warray-bounds-43.c: Likewise.
> * gcc.dg/pr107787.c: New test.
>
> gcc/c-family/ChangeLog:
>
> * c-common.cc (warn_array_bounds): Use OPT_Warray_bounds_
> instead of OPT_Warray_bounds.
> ---
>  gcc/builtins.cc                         |  6 ++--
>  gcc/c-family/c-common.cc                |  4 +--
>  gcc/common.opt                          |  3 +-
>  gcc/diagnostic-spec.cc                  |  1 -
>  gcc/gimple-array-bounds.cc              | 38 ++++++++++++-------------
>  gcc/gimple-ssa-warn-restrict.cc         |  2 +-
>  gcc/testsuite/gcc.dg/Warray-bounds-34.c |  2 +-
>  gcc/testsuite/gcc.dg/Warray-bounds-43.c |  6 ++--
>  gcc/testsuite/gcc.dg/pr107787.c         | 13 +++++++++
>  9 files changed, 43 insertions(+), 32 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.dg/pr107787.c
>
> diff --git a/gcc/builtins.cc b/gcc/builtins.cc
> index 4dc1ca672b2..02c4fefa86f 100644
> --- a/gcc/builtins.cc
> +++ b/gcc/builtins.cc
> @@ -696,14 +696,14 @@ c_strlen (tree arg, int only_value, c_strlen_data *data, unsigned eltsize)
>      {
>        /* Suppress multiple warnings for propagated constant strings.  */
>        if (only_value != 2
> -  && !warning_suppressed_p (arg, OPT_Warray_bounds)
> -  && warning_at (loc, OPT_Warray_bounds,
> +  && !warning_suppressed_p (arg, OPT_Warray_bounds_)
> +  && warning_at (loc, OPT_Warray_bounds_,
>   "offset %qwi outside bounds of constant string",
>   eltoff))
>   {
>    if (decl)
>      inform (DECL_SOURCE_LOCATION (decl), "%qE declared here", decl);
> -  suppress_warning (arg, OPT_Warray_bounds);
> +  suppress_warning (arg, OPT_Warray_bounds_);
>   }
>        return NULL_TREE;
>      }
> diff --git a/gcc/c-family/c-common.cc b/gcc/c-family/c-common.cc
> index 6f1f21bc4c1..b0da6886ccf 100644
> --- a/gcc/c-family/c-common.cc
> +++ b/gcc/c-family/c-common.cc
> @@ -6811,7 +6811,7 @@ fold_offsetof (tree expr, tree type, enum tree_code ctx)
>       definition thereof.  */
>    if (TREE_CODE (v) == ARRAY_REF
>        || TREE_CODE (v) == COMPONENT_REF)
> -    warning (OPT_Warray_bounds,
> +    warning (OPT_Warray_bounds_,
>       "index %E denotes an offset "
>       "greater than size of %qT",
>       t, TREE_TYPE (TREE_OPERAND (expr, 0)));
> @@ -8534,7 +8534,7 @@ convert_vector_to_array_for_subscript (location_t loc,
>        if (TREE_CODE (index) == INTEGER_CST)
>          if (!tree_fits_uhwi_p (index)
>      || maybe_ge (tree_to_uhwi (index), TYPE_VECTOR_SUBPARTS (type)))
> -          warning_at (loc, OPT_Warray_bounds, "index value is out of bound");
> +          warning_at (loc, OPT_Warray_bounds_, "index value is out of bound");
>
>        /* We are building an ARRAY_REF so mark the vector as addressable
>           to not run into the gimplifiers premature setting of DECL_GIMPLE_REG_P
> diff --git a/gcc/common.opt b/gcc/common.opt
> index 26e9d1cc4e7..f91b631f257 100644
> --- a/gcc/common.opt
> +++ b/gcc/common.opt
> @@ -539,8 +539,7 @@ Common Var(warn_aggressive_loop_optimizations) Init(1) Warning
>  Warn if a loop with constant number of iterations triggers undefined behavior.
>
>  Warray-bounds
> -Common Var(warn_array_bounds) Warning
> -Warn if an array is accessed out of bounds.
> +Common Alias(Warray-bounds=, 1, 0) Warning
>
>  Warray-bounds=
>  Common Joined RejectNegative UInteger Var(warn_array_bounds) Warning IntegerRange(0, 2)
> diff --git a/gcc/diagnostic-spec.cc b/gcc/diagnostic-spec.cc
> index aece89619e7..7a03fc493e6 100644
> --- a/gcc/diagnostic-spec.cc
> +++ b/gcc/diagnostic-spec.cc
> @@ -79,7 +79,6 @@ nowarn_spec_t::nowarn_spec_t (opt_code opt)
>        break;
>
>        /* Access warning group.  */
> -    case OPT_Warray_bounds:
>      case OPT_Warray_bounds_:
>      case OPT_Wformat_overflow_:
>      case OPT_Wformat_truncation_:
> diff --git a/gcc/gimple-array-bounds.cc b/gcc/gimple-array-bounds.cc
> index fbf448e045d..7af85b86f75 100644
> --- a/gcc/gimple-array-bounds.cc
> +++ b/gcc/gimple-array-bounds.cc
> @@ -182,7 +182,7 @@ bool
>  array_bounds_checker::check_array_ref (location_t location, tree ref,
>         gimple *stmt, bool ignore_off_by_one)
>  {
> -  if (warning_suppressed_p (ref, OPT_Warray_bounds))
> +  if (warning_suppressed_p (ref, OPT_Warray_bounds_))
>      /* Return true to have the caller prevent warnings for enclosing
>         refs.  */
>      return true;
> @@ -287,7 +287,7 @@ array_bounds_checker::check_array_ref (location_t location, tree ref,
>
>    /* Empty array.  */
>    if (up_bound && tree_int_cst_equal (low_bound, up_bound_p1))
> -    warned = warning_at (location, OPT_Warray_bounds,
> +    warned = warning_at (location, OPT_Warray_bounds_,
>   "array subscript %E is outside array bounds of %qT",
>   low_sub, artype);
>
> @@ -313,7 +313,7 @@ array_bounds_checker::check_array_ref (location_t location, tree ref,
>        : tree_int_cst_le (up_bound, up_sub))
>    && TREE_CODE (low_sub) == INTEGER_CST
>    && tree_int_cst_le (low_sub, low_bound))
> - warned = warning_at (location, OPT_Warray_bounds,
> + warned = warning_at (location, OPT_Warray_bounds_,
>       "array subscript [%E, %E] is outside "
>       "array bounds of %qT",
>       low_sub, up_sub, artype);
> @@ -323,12 +323,12 @@ array_bounds_checker::check_array_ref (location_t location, tree ref,
>     && (ignore_off_by_one
>         ? !tree_int_cst_le (up_sub, up_bound_p1)
>         : !tree_int_cst_le (up_sub, up_bound)))
> -    warned = warning_at (location, OPT_Warray_bounds,
> +    warned = warning_at (location, OPT_Warray_bounds_,
>   "array subscript %E is above array bounds of %qT",
>   up_sub, artype);
>    else if (TREE_CODE (low_sub) == INTEGER_CST
>     && tree_int_cst_lt (low_sub, low_bound))
> -    warned = warning_at (location, OPT_Warray_bounds,
> +    warned = warning_at (location, OPT_Warray_bounds_,
>   "array subscript %E is below array bounds of %qT",
>   low_sub, artype);
>
> @@ -353,7 +353,7 @@ array_bounds_checker::check_array_ref (location_t location, tree ref,
>        /* Avoid more warnings when checking more significant subscripts
>   of the same expression.  */
>        ref = TREE_OPERAND (ref, 0);
> -      suppress_warning (ref, OPT_Warray_bounds);
> +      suppress_warning (ref, OPT_Warray_bounds_);
>
>        if (decl)
>   ref = decl;
> @@ -393,7 +393,7 @@ bool
>  array_bounds_checker::check_mem_ref (location_t location, tree ref,
>       bool ignore_off_by_one)
>  {
> -  if (warning_suppressed_p (ref, OPT_Warray_bounds))
> +  if (warning_suppressed_p (ref, OPT_Warray_bounds_))
>      return false;
>
>    /* The statement used to allocate the array or null.  */
> @@ -493,12 +493,12 @@ array_bounds_checker::check_mem_ref (location_t location, tree ref,
>    if (lboob)
>      {
>        if (offrange[0] == offrange[1])
> - warned = warning_at (location, OPT_Warray_bounds,
> + warned = warning_at (location, OPT_Warray_bounds_,
>       "array subscript %wi is outside array bounds "
>       "of %qT",
>       offrange[0].to_shwi (), reftype);
>        else
> - warned = warning_at (location, OPT_Warray_bounds,
> + warned = warning_at (location, OPT_Warray_bounds_,
>       "array subscript [%wi, %wi] is outside "
>       "array bounds of %qT",
>       offrange[0].to_shwi (),
> @@ -513,7 +513,7 @@ array_bounds_checker::check_mem_ref (location_t location, tree ref,
>   backtype = build_array_type_nelts (unsigned_char_type_node,
>     aref.sizrng[1].to_uhwi ());
>
> -      warned = warning_at (location, OPT_Warray_bounds,
> +      warned = warning_at (location, OPT_Warray_bounds_,
>     "array subscript %<%T[%wi]%> is partly "
>     "outside array bounds of %qT",
>     axstype, offrange[0].to_shwi (), backtype);
> @@ -523,7 +523,7 @@ array_bounds_checker::check_mem_ref (location_t location, tree ref,
>      {
>        /* TODO: Determine the access from the statement and use it.  */
>        aref.inform_access (access_none);
> -      suppress_warning (ref, OPT_Warray_bounds);
> +      suppress_warning (ref, OPT_Warray_bounds_);
>        return true;
>      }
>
> @@ -536,11 +536,11 @@ array_bounds_checker::check_mem_ref (location_t location, tree ref,
>      {
>        HOST_WIDE_INT tmpidx = (aref.offmax[i] / eltsize).to_shwi ();
>
> -      if (warning_at (location, OPT_Warray_bounds,
> +      if (warning_at (location, OPT_Warray_bounds_,
>        "intermediate array offset %wi is outside array bounds "
>        "of %qT", tmpidx, reftype))
>   {
> -  suppress_warning (ref, OPT_Warray_bounds);
> +  suppress_warning (ref, OPT_Warray_bounds_);
>    return true;
>   }
>      }
> @@ -572,7 +572,7 @@ array_bounds_checker::check_addr_expr (location_t location, tree t,
>   warned = check_mem_ref (location, t, ignore_off_by_one);
>
>        if (warned)
> - suppress_warning (t, OPT_Warray_bounds);
> + suppress_warning (t, OPT_Warray_bounds_);
>
>        t = TREE_OPERAND (t, 0);
>      }
> @@ -580,7 +580,7 @@ array_bounds_checker::check_addr_expr (location_t location, tree t,
>
>    if (TREE_CODE (t) != MEM_REF
>        || TREE_CODE (TREE_OPERAND (t, 0)) != ADDR_EXPR
> -      || warning_suppressed_p (t, OPT_Warray_bounds))
> +      || warning_suppressed_p (t, OPT_Warray_bounds_))
>      return;
>
>    tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
> @@ -615,7 +615,7 @@ array_bounds_checker::check_addr_expr (location_t location, tree t,
>    dump_generic_expr (MSG_NOTE, TDF_SLIM, t);
>    fprintf (dump_file, "\n");
>   }
> -      warned = warning_at (location, OPT_Warray_bounds,
> +      warned = warning_at (location, OPT_Warray_bounds_,
>     "array subscript %wi is below "
>     "array bounds of %qT",
>     idx.to_shwi (), TREE_TYPE (tem));
> @@ -629,7 +629,7 @@ array_bounds_checker::check_addr_expr (location_t location, tree t,
>    dump_generic_expr (MSG_NOTE, TDF_SLIM, t);
>    fprintf (dump_file, "\n");
>   }
> -      warned = warning_at (location, OPT_Warray_bounds,
> +      warned = warning_at (location, OPT_Warray_bounds_,
>     "array subscript %wu is above "
>     "array bounds of %qT",
>     idx.to_uhwi (), TREE_TYPE (tem));
> @@ -640,7 +640,7 @@ array_bounds_checker::check_addr_expr (location_t location, tree t,
>        if (DECL_P (t))
>   inform (DECL_SOURCE_LOCATION (t), "while referencing %qD", t);
>
> -      suppress_warning (t, OPT_Warray_bounds);
> +      suppress_warning (t, OPT_Warray_bounds_);
>      }
>  }
>
> @@ -740,7 +740,7 @@ array_bounds_checker::check_array_bounds (tree *tp, int *walk_subtree,
>    /* Propagate the no-warning bit to the outer statement to avoid also
>       issuing -Wstringop-overflow/-overread for the out-of-bounds accesses.  */
>    if (warned)
> -    suppress_warning (wi->stmt, OPT_Warray_bounds);
> +    suppress_warning (wi->stmt, OPT_Warray_bounds_);
>
>    return NULL_TREE;
>  }
> diff --git a/gcc/gimple-ssa-warn-restrict.cc b/gcc/gimple-ssa-warn-restrict.cc
> index 832456ba6fc..107ba278798 100644
> --- a/gcc/gimple-ssa-warn-restrict.cc
> +++ b/gcc/gimple-ssa-warn-restrict.cc
> @@ -1734,7 +1734,7 @@ maybe_diag_access_bounds (gimple *call, tree func, int strict,
>    if (!oobref)
>      return no_warning;
>
> -  const opt_code opt = OPT_Warray_bounds;
> +  const opt_code opt = OPT_Warray_bounds_;
>    /* Return true without issuing a warning.  */
>    if (!do_warn)
>      return opt;
> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-34.c b/gcc/testsuite/gcc.dg/Warray-bounds-34.c
> index cea7c4b32a2..1b2a098ad86 100644
> --- a/gcc/testsuite/gcc.dg/Warray-bounds-34.c
> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-34.c
> @@ -7,7 +7,7 @@ int x;
>
>  inline void foo (int i)
>  {
> -  a[i + 1] = 123;   /* { dg-warning "\\\[-Warray-bounds]" } */
> +  a[i + 1] = 123;   /* { dg-warning "\\\[-Warray-bounds" } */
>  }
>
>  int bar (void)
> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-43.c b/gcc/testsuite/gcc.dg/Warray-bounds-43.c
> index 0f521a7250d..43a83315787 100644
> --- a/gcc/testsuite/gcc.dg/Warray-bounds-43.c
> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-43.c
> @@ -19,7 +19,7 @@ NOIPA int g2 (int i)
>
>    sink (p0, p1, p2);
>
> -  return p2[8];     // { dg-warning "\\\[-Warray-bounds]" }
> +  return p2[8];     // { dg-warning "\\\[-Warray-bounds" }
>  }
>
>  NOIPA int g3 (int i)
> @@ -33,7 +33,7 @@ NOIPA int g3 (int i)
>
>    sink (p0, p1, p2, p3);
>
> -  return p3[7];     // { dg-warning "\\\[-Warray-bounds]" }
> +  return p3[7];     // { dg-warning "\\\[-Warray-bounds" }
>  }
>
>  NOIPA int g4 (int i)
> @@ -48,7 +48,7 @@ NOIPA int g4 (int i)
>
>    sink (p0, p1, p2, p3, p4);
>
> -  return p4[6];     // { dg-warning "\\\[-Warray-bounds]" }
> +  return p4[6];     // { dg-warning "\\\[-Warray-bounds" }
>  }
>
>  NOIPA int g5 (int i)
> diff --git a/gcc/testsuite/gcc.dg/pr107787.c b/gcc/testsuite/gcc.dg/pr107787.c
> new file mode 100644
> index 00000000000..922dbff8b2a
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/pr107787.c
> @@ -0,0 +1,13 @@
> +/* PR driver/107787 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -Werror=array-bounds=1" } */
> +/* { dg-message "some warnings being treated as errors" "" {target "*-*-*"} 0 } */
> +
> +int a[10];     /* { dg-note "while referencing" } */
> +
> +int* f(void) {
> +
> +    a[-1] = 0; /* { dg-error "is below array bounds" } */
> +
> +    return a;
> +}
> --
> 2.25.1
>