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

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

On Wed, Nov 23, 2022 at 3:08 PM Iskander Shakirzyanov via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Hi!
> Sorry for the initially missing description.
> The following patch changes the definition of -Warray-bounds to an Alias to -Warray-bounds=1. This is necessary for the correct use of -Werror=array-bounds=X, for more information see bug report 107787 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107787)
> 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() (opts-common.cc:1880) is called, DK_ERROR is set for the -Warray-bounds= option, but in diagnostic_report_diagnostic() (diagnostic.cc:1446) through warning_at() passes opt_index of -Warray-bounds, so information about DK_ERROR is lost.

How did you test the patch?  If you bootstrapped it and ran the
testsuite then it's OK.

Thanks,
Richard.

>
> From 51559e862d191a1f51cc9af11f0d9be5fbc0b43c Mon Sep 17 00:00:00 2001
> From: Iskander Shakirzyanov <iskander@ispras.ru>
> Date: Wed, 23 Nov 2022 12:26:47 +0000
> Subject: [PATCH] Make Warray-bounds alias to Warray-bounds= [PR107787]
>
>         PR driver/107787
>
> 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:
>
>         * 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                  |  2 +-
>  gcc/diagnostic-spec.cc          |  1 -
>  gcc/gimple-array-bounds.cc      | 38 ++++++++++++++++-----------------
>  gcc/gimple-ssa-warn-restrict.cc |  2 +-
>  gcc/testsuite/gcc.dg/pr107787.c | 13 +++++++++++
>  7 files changed, 39 insertions(+), 27 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..e475d6e56eb 100644
> --- a/gcc/common.opt
> +++ b/gcc/common.opt
> @@ -539,7 +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
> +Common Alias(Warray-bounds=, 1, 0) Warning
>  Warn if an array is accessed out of bounds.
>
>  Warray-bounds=
> 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/pr107787.c b/gcc/testsuite/gcc.dg/pr107787.c
> new file mode 100644
> index 00000000000..79112691b63
> --- /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
>