> On Dec 14, 2022, at 9:08 AM, Qing Zhao via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
>
>
>
>> On Dec 14, 2022, at 4:03 AM, Richard Biener <rguent...@suse.de> wrote:
>>
>> On Tue, 13 Dec 2022, Qing Zhao wrote:
>>
>>> Richard,
>>>
>>> Do you have any decision on this one?
>>> Do we need this warning option For GCC?
>>
>> Looking at the testcases it seems that the diagnostic amends
>> -Warray-bounds diagnostics for trailing but not flexible arrays?
>
> Yes.
>
>> Wouldn't it be better to generally diagnose this, so have
>> -Warray-bounds, with -fstrict-flex-arrays, for
>>
>> struct X { int a[1]; };
>> int foo (struct X *p)
>> {
>> return p->a[1];
>> }
>>
>> emit
>>
>> warning: array subscript 1 is above array bounds ...
>> note: the trailing array is only a flexible array member with
>> -fno-strict-flex-arrays
>
> This is good too.
> My only concern with doing this is, the default warning messages of
> -Warray-bounds would be different than
> the current ones, will this have any impact on the current users?
My bad, the default warning message of -Warray-bounds without
-fstrict-flex-arrays should not be changed.
Only when -fstrict-flex-arrays=N (N>0), the warning messages of -Warray-bounds
will be different than the current one.
This should be fine.
>
>>
>> ? Having -Wstrict-flex-arrays=N and N not agree with the
>> -fstrict-flex-arrays level sounds hardly useful to me but the
>> information that we ran into a trailing array but didn't consider
>> it a flex array because of -fstrict-flex-arrays is always a
>> useful information?
>
> -Wstrict-flex-arrays does NOT have the argument “N”. Its level will be
> consistent with the level “N” of the corresponding
> -fstrict-flex-array=N.
> -Wstrict-flex-arrays option is only valid when -fstrict-flex-arrays is
> present, it will report any misuse of treating trailing array
> as flexible array at the LEVEL of -fstrict-flex-arrays.
>
> Let me know if it is still not very clear.
>
> thanks.
>
> Qing
>>
>> But maybe I misunderstood this new diagnostic?
>>
>> Thanks,
>> Richard.
>>
>>
>>> thanks.
>>>
>>> Qing
>>>
>>>> On Dec 6, 2022, at 11:18 AM, Qing Zhao <qing.z...@oracle.com> wrote:
>>>>
>>>> '-Wstrict-flex-arrays'
>>>> Warn about inproper usages of flexible array members according to
>>>> the LEVEL of the 'strict_flex_array (LEVEL)' attribute attached to
>>>> the trailing array field of a structure if it's available,
>>>> otherwise according to the LEVEL of the option
>>>> '-fstrict-flex-arrays=LEVEL'.
>>>>
>>>> This option is effective only when LEVEL is bigger than 0.
>>>> Otherwise, it will be ignored with a warning.
>>>>
>>>> when LEVEL=1, warnings will be issued for a trailing array
>>>> reference of a structure that have 2 or more elements if the
>>>> trailing array is referenced as a flexible array member.
>>>>
>>>> when LEVEL=2, in addition to LEVEL=1, additional warnings will be
>>>> issued for a trailing one-element array reference of a structure if
>>>> the array is referenced as a flexible array member.
>>>>
>>>> when LEVEL=3, in addition to LEVEL=2, additional warnings will be
>>>> issued for a trailing zero-length array reference of a structure if
>>>> the array is referenced as a flexible array member.
>>>>
>>>> gcc/ChangeLog:
>>>>
>>>> * doc/invoke.texi: Document -Wstrict-flex-arrays option.
>>>> * gimple-array-bounds.cc (check_out_of_bounds_and_warn): Add two more
>>>> arguments.
>>>> (array_bounds_checker::check_array_ref): Issue warnings for
>>>> -Wstrict-flex-arrays.
>>>> * opts.cc (finish_options): Issue warning for unsupported combination
>>>> of -Wstrict_flex_arrays and -fstrict-flex-array.
>>>> * tree-vrp.cc (execute_ranger_vrp): Enable the pass when
>>>> warn_strict_flex_array is true.
>>>>
>>>> gcc/c-family/ChangeLog:
>>>>
>>>> * c.opt (Wstrict-flex-arrays): New option.
>>>>
>>>> gcc/testsuite/ChangeLog:
>>>>
>>>> * gcc.dg/Warray-bounds-flex-arrays-1.c: Update testing case with
>>>> -Wstrict-flex-arrays.
>>>> * gcc.dg/Warray-bounds-flex-arrays-2.c: Likewise.
>>>> * gcc.dg/Warray-bounds-flex-arrays-3.c: Likewise.
>>>> * gcc.dg/Warray-bounds-flex-arrays-4.c: Likewise.
>>>> * gcc.dg/Warray-bounds-flex-arrays-5.c: Likewise.
>>>> * gcc.dg/Warray-bounds-flex-arrays-6.c: Likewise.
>>>> * c-c++-common/Wstrict-flex-arrays.c: New test.
>>>> * gcc.dg/Wstrict-flex-arrays-2.c: New test.
>>>> * gcc.dg/Wstrict-flex-arrays-3.c: New test.
>>>> * gcc.dg/Wstrict-flex-arrays.c: New test.
>>>> ---
>>>> gcc/c-family/c.opt | 5 +
>>>> gcc/doc/invoke.texi | 27 ++++-
>>>> gcc/gimple-array-bounds.cc | 103 ++++++++++++++----
>>>> gcc/opts.cc | 8 ++
>>>> .../c-c++-common/Wstrict-flex-arrays.c | 9 ++
>>>> .../gcc.dg/Warray-bounds-flex-arrays-1.c | 5 +-
>>>> .../gcc.dg/Warray-bounds-flex-arrays-2.c | 6 +-
>>>> .../gcc.dg/Warray-bounds-flex-arrays-3.c | 7 +-
>>>> .../gcc.dg/Warray-bounds-flex-arrays-4.c | 5 +-
>>>> .../gcc.dg/Warray-bounds-flex-arrays-5.c | 6 +-
>>>> .../gcc.dg/Warray-bounds-flex-arrays-6.c | 7 +-
>>>> gcc/testsuite/gcc.dg/Wstrict-flex-arrays-2.c | 39 +++++++
>>>> gcc/testsuite/gcc.dg/Wstrict-flex-arrays-3.c | 39 +++++++
>>>> gcc/testsuite/gcc.dg/Wstrict-flex-arrays.c | 39 +++++++
>>>> gcc/tree-vrp.cc | 2 +-
>>>> 15 files changed, 273 insertions(+), 34 deletions(-)
>>>> create mode 100644 gcc/testsuite/c-c++-common/Wstrict-flex-arrays.c
>>>> create mode 100644 gcc/testsuite/gcc.dg/Wstrict-flex-arrays-2.c
>>>> create mode 100644 gcc/testsuite/gcc.dg/Wstrict-flex-arrays-3.c
>>>> create mode 100644 gcc/testsuite/gcc.dg/Wstrict-flex-arrays.c
>>>>
>>>> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
>>>> index 0d0ad0a6374..33edeefd285 100644
>>>> --- a/gcc/c-family/c.opt
>>>> +++ b/gcc/c-family/c.opt
>>>> @@ -976,6 +976,11 @@ Wstringop-truncation
>>>> C ObjC C++ LTO ObjC++ Var(warn_stringop_truncation) Warning Init (1)
>>>> LangEnabledBy(C ObjC C++ LTO ObjC++, Wall)
>>>> Warn about truncation in string manipulation functions like strncat and
>>>> strncpy.
>>>>
>>>> +Wstrict-flex-arrays
>>>> +C C++ Var(warn_strict_flex_arrays) Warning
>>>> +Warn about inproper usages of flexible array members
>>>> +according to the level of -fstrict-flex-arrays.
>>>> +
>>>> Wsuggest-attribute=format
>>>> C ObjC C++ ObjC++ Var(warn_suggest_attribute_format) Warning
>>>> Warn about functions which might be candidates for format attributes.
>>>> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
>>>> index 726392409b6..4402b0427ef 100644
>>>> --- a/gcc/doc/invoke.texi
>>>> +++ b/gcc/doc/invoke.texi
>>>> @@ -398,7 +398,7 @@ Objective-C and Objective-C++ Dialects}.
>>>> -Wstrict-aliasing=n -Wstrict-overflow -Wstrict-overflow=@var{n} @gol
>>>> -Wstring-compare @gol
>>>> -Wno-stringop-overflow -Wno-stringop-overread @gol
>>>> --Wno-stringop-truncation @gol
>>>> +-Wno-stringop-truncation -Wstrict-flex-arrays @gol
>>>> -Wsuggest-attribute=@r{[}pure@r{|}const@r{|}noreturn@r{|}format@r{|}malloc@r{]}
>>>> @gol
>>>> -Wswitch -Wno-switch-bool -Wswitch-default -Wswitch-enum @gol
>>>> -Wno-switch-outside-range -Wno-switch-unreachable -Wsync-nand @gol
>>>> @@ -7835,6 +7835,31 @@ however, are not suitable arguments to functions
>>>> that expect
>>>> such arrays GCC issues warnings unless it can prove that the use is
>>>> safe. @xref{Common Variable Attributes}.
>>>>
>>>> +@item -Wstrict-flex-arrays
>>>> +@opindex Wstrict-flex-arrays
>>>> +@opindex Wno-strict-flex-arrays
>>>> +Warn about inproper usages of flexible array members
>>>> +according to the @var{level} of the @code{strict_flex_array (@var{level})}
>>>> +attribute attached to the trailing array field of a structure if it's
>>>> +available, otherwise according to the @var{level} of the option
>>>> +@option{-fstrict-flex-arrays=@var{level}}.
>>>> +
>>>> +This option is effective only when @var{level} is bigger than 0.
>>>> Otherwise,
>>>> +it will be ignored with a warning.
>>>> +
>>>> +when @var{level}=1, warnings will be issued for a trailing array reference
>>>> +of a structure that have 2 or more elements if the trailing array is
>>>> referenced
>>>> +as a flexible array member.
>>>> +
>>>> +when @var{level}=2, in addition to @var{level}=1, additional warnings
>>>> will be
>>>> +issued for a trailing one-element array reference of a structure
>>>> +if the array is referenced as a flexible array member.
>>>> +
>>>> +when @var{level}=3, in addition to @var{level}=2, additional warnings
>>>> will be
>>>> +issued for a trailing zero-length array reference of a structure
>>>> +if the array is referenced as a flexible array member.
>>>> +
>>>> +
>>>> @item
>>>> -Wsuggest-attribute=@r{[}pure@r{|}const@r{|}noreturn@r{|}format@r{|}cold@r{|}malloc@r{]}
>>>> @opindex Wsuggest-attribute=
>>>> @opindex Wno-suggest-attribute=
>>>> diff --git a/gcc/gimple-array-bounds.cc b/gcc/gimple-array-bounds.cc
>>>> index db3459af325..825f11331b5 100644
>>>> --- a/gcc/gimple-array-bounds.cc
>>>> +++ b/gcc/gimple-array-bounds.cc
>>>> @@ -252,25 +252,34 @@ get_up_bounds_for_array_ref (tree ref, tree *decl,
>>>>
>>>> /* Given the LOW_SUB_ORG, LOW_SUB and UP_SUB, and the computed UP_BOUND
>>>> and UP_BOUND_P1, check whether the array reference REF is out of bound.
>>>> - Issue warnings if out of bound, return TRUE if warnings are issued.
>>>> */
>>>> + When out of bounds, set OUT_OF_BOUND to true.
>>>> + Issue warnings if FOR_ARRAY_BOUND is true.
>>>> + return TRUE if warnings are issued. */
>>>> +
>>>>
>>>> static bool
>>>> check_out_of_bounds_and_warn (location_t location, tree ref,
>>>> tree low_sub_org, tree low_sub, tree up_sub,
>>>> tree up_bound, tree up_bound_p1,
>>>> const value_range *vr,
>>>> - bool ignore_off_by_one)
>>>> + bool ignore_off_by_one, bool for_array_bound,
>>>> + bool *out_of_bound)
>>>> {
>>>> tree low_bound = array_ref_low_bound (ref);
>>>> tree artype = TREE_TYPE (TREE_OPERAND (ref, 0));
>>>>
>>>> bool warned = false;
>>>> + *out_of_bound = false;
>>>>
>>>> /* Empty array. */
>>>> if (up_bound && tree_int_cst_equal (low_bound, up_bound_p1))
>>>> - warned = warning_at (location, OPT_Warray_bounds_,
>>>> - "array subscript %E is outside array bounds of %qT",
>>>> - low_sub_org, artype);
>>>> + {
>>>> + *out_of_bound = true;
>>>> + if (for_array_bound)
>>>> + warned = warning_at (location, OPT_Warray_bounds_,
>>>> + "array subscript %E is outside array"
>>>> + " bounds of %qT", low_sub_org, artype);
>>>> + }
>>>>
>>>> if (warned)
>>>> ; /* Do nothing. */
>>>> @@ -283,24 +292,33 @@ check_out_of_bounds_and_warn (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_,
>>>> - "array subscript [%E, %E] is outside "
>>>> - "array bounds of %qT",
>>>> - low_sub, up_sub, artype);
>>>> + {
>>>> + *out_of_bound = true;
>>>> + warned = warning_at (location, OPT_Warray_bounds_,
>>>> + "array subscript [%E, %E] is outside "
>>>> + "array bounds of %qT",
>>>> + low_sub, up_sub, artype);
>>>> + }
>>>> }
>>>> else if (up_bound
>>>> && TREE_CODE (up_sub) == INTEGER_CST
>>>> && (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_,
>>>> - "array subscript %E is above array bounds of %qT",
>>>> - up_sub, artype);
>>>> + {
>>>> + *out_of_bound = true;
>>>> + 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_,
>>>> - "array subscript %E is below array bounds of %qT",
>>>> - low_sub, artype);
>>>> + {
>>>> + *out_of_bound = true;
>>>> + warned = warning_at (location, OPT_Warray_bounds_,
>>>> + "array subscript %E is below array bounds of %qT",
>>>> + low_sub, artype);
>>>> + }
>>>> return warned;
>>>> }
>>>>
>>>> @@ -333,14 +351,21 @@ array_bounds_checker::check_array_ref (location_t
>>>> location, tree ref,
>>>>
>>>> tree arg = TREE_OPERAND (ref, 0);
>>>> const bool compref = TREE_CODE (arg) == COMPONENT_REF;
>>>> + unsigned int strict_flex_array_level = flag_strict_flex_arrays;
>>>>
>>>> if (compref)
>>>> - /* Try to determine special array member type for this COMPONENT_REF.
>>>> */
>>>> - sam = component_ref_sam_type (arg);
>>>> + {
>>>> + /* Try to determine special array member type for this
>>>> COMPONENT_REF. */
>>>> + sam = component_ref_sam_type (arg);
>>>> + /* Get the level of strict_flex_array for this array field. */
>>>> + tree afield_decl = TREE_OPERAND (arg, 1);
>>>> + strict_flex_array_level = strict_flex_array_level_of (afield_decl);
>>>> + }
>>>>
>>>> get_up_bounds_for_array_ref (ref, &decl, &up_bound, &up_bound_p1);
>>>>
>>>> bool warned = false;
>>>> + bool out_of_bound = false;
>>>>
>>>> tree artype = TREE_TYPE (TREE_OPERAND (ref, 0));
>>>> tree low_sub_org = TREE_OPERAND (ref, 1);
>>>> @@ -361,7 +386,8 @@ array_bounds_checker::check_array_ref (location_t
>>>> location, tree ref,
>>>> warned = check_out_of_bounds_and_warn (location, ref,
>>>> low_sub_org, low_sub, up_sub,
>>>> up_bound, up_bound_p1, vr,
>>>> - ignore_off_by_one);
>>>> + ignore_off_by_one, warn_array_bounds,
>>>> + &out_of_bound);
>>>>
>>>>
>>>> if (!warned && sam == special_array_member::int_0)
>>>> @@ -373,19 +399,56 @@ array_bounds_checker::check_array_ref (location_t
>>>> location, tree ref,
>>>> "of an interior zero-length array %qT")),
>>>> low_sub, artype);
>>>>
>>>> - if (warned)
>>>> + if (warned || out_of_bound)
>>>> {
>>>> - if (dump_file && (dump_flags & TDF_DETAILS))
>>>> + if (warned && dump_file && (dump_flags & TDF_DETAILS))
>>>> {
>>>> fprintf (dump_file, "Array bound warning for ");
>>>> dump_generic_expr (MSG_NOTE, TDF_SLIM, ref);
>>>> fprintf (dump_file, "\n");
>>>> }
>>>>
>>>> + /* issue warnings for -Wstrict-flex-arrays according to the level of
>>>> + flag_strict_flex_arrays. */
>>>> + if (out_of_bound && warn_strict_flex_arrays)
>>>> + switch (strict_flex_array_level)
>>>> + {
>>>> + case 3:
>>>> + /* Issue additional warnings for trailing arrays [0]. */
>>>> + if (sam == special_array_member::trail_0)
>>>> + warned = warning_at (location, OPT_Wstrict_flex_arrays,
>>>> + "trailing array %qT should not be used as "
>>>> + "a flexible array member for level 3",
>>>> + artype);
>>>> + /* FALLTHROUGH. */
>>>> + case 2:
>>>> + /* Issue additional warnings for trailing arrays [1]. */
>>>> + if (sam == special_array_member::trail_1)
>>>> + warned = warning_at (location, OPT_Wstrict_flex_arrays,
>>>> + "trailing array %qT should not be used as "
>>>> + "a flexible array member for level 2 and "
>>>> + "above", artype);
>>>> + /* FALLTHROUGH. */
>>>> + case 1:
>>>> + /* Issue warnings for trailing arrays [n]. */
>>>> + if (sam == special_array_member::trail_n)
>>>> + warned = warning_at (location, OPT_Wstrict_flex_arrays,
>>>> + "trailing array %qT should not be used as "
>>>> + "a flexible array member for level 1 and "
>>>> + "above", artype);
>>>> + break;
>>>> + case 0:
>>>> + /* Do nothing. */
>>>> + break;
>>>> + default:
>>>> + gcc_unreachable ();
>>>> + }
>>>> +
>>>> /* 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_Wstrict_flex_arrays);
>>>>
>>>> if (decl)
>>>> ref = decl;
>>>> diff --git a/gcc/opts.cc b/gcc/opts.cc
>>>> index 73fc97756e4..8db53ad6c77 100644
>>>> --- a/gcc/opts.cc
>>>> +++ b/gcc/opts.cc
>>>> @@ -1411,6 +1411,14 @@ finish_options (struct gcc_options *opts, struct
>>>> gcc_options *opts_set,
>>>> opts->x_profile_flag = 0;
>>>> }
>>>>
>>>> + if (opts->x_warn_strict_flex_arrays)
>>>> + if (opts->x_flag_strict_flex_arrays == 0)
>>>> + {
>>>> + opts->x_warn_strict_flex_arrays = 0;
>>>> + warning_at (UNKNOWN_LOCATION, 0,
>>>> + "%<-Wstrict-flex-arrays%> is ignored when"
>>>> + " %<-fstrict-flex-arrays%> does not present");
>>>> + }
>>>>
>>>> diagnose_options (opts, opts_set, loc);
>>>> }
>>>> diff --git a/gcc/testsuite/c-c++-common/Wstrict-flex-arrays.c
>>>> b/gcc/testsuite/c-c++-common/Wstrict-flex-arrays.c
>>>> new file mode 100644
>>>> index 00000000000..72b4b7c6406
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/c-c++-common/Wstrict-flex-arrays.c
>>>> @@ -0,0 +1,9 @@
>>>> +/* Test the usage of option -Wstrict-flex-arrays. */
>>>> +/* { dg-do compile } */
>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays" } */
>>>> +
>>>> +int main(int argc, char *argv[])
>>>> +{
>>>> + return 0;
>>>> +}
>>>> +/* { dg-warning "is ignored when \'-fstrict-flex-arrays\' does not
>>>> present" "" { target *-*-* } 0 } */
>>>> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-1.c
>>>> b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-1.c
>>>> index d36ba4d86cb..65c9fec43af 100644
>>>> --- a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-1.c
>>>> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-1.c
>>>> @@ -1,6 +1,6 @@
>>>> -/* Test -fstrict-flex-arrays + -Warray-bounds. */
>>>> +/* Test -fstrict-flex-arrays + -Warray-bounds + -Wstrict-flex-arrays. */
>>>> /* { dg-do compile} */
>>>> -/* { dg-options "-O2 -fstrict-flex-arrays=1 -Warray-bounds" } */
>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=1
>>>> -Warray-bounds" } */
>>>>
>>>> struct trailing_array_1 {
>>>> int a;
>>>> @@ -32,6 +32,7 @@ void __attribute__((__noinline__)) stuff(
>>>> struct trailing_array_4 *trailing_flex)
>>>> {
>>>> normal->c[5] = 5; /*{ dg-warning "array subscript 5 is above
>>>> array bounds of" } */
>>>> + /*{ dg-warning "should not be used as a
>>>> flexible array member for level 1 and above" "" { target *-*-* } .-1 } */
>>>> trailing_1->c[2] = 2; /* { dg-bogus "array subscript " } */
>>>> trailing_0->c[1] = 1; /* { dg-bogus "array subscript " } */
>>>> trailing_flex->c[10] = 10; /* { dg-bogus "array subscript " } */
>>>> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-2.c
>>>> b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-2.c
>>>> index f63206e1948..2b5a895c598 100644
>>>> --- a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-2.c
>>>> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-2.c
>>>> @@ -1,6 +1,6 @@
>>>> -/* Test -fstrict-flex-arrays + -Warray-bounds. */
>>>> +/* Test -fstrict-flex-arrays + -Warray-bounds + -Wstrict-flex-arrays. */
>>>> /* { dg-do compile } */
>>>> -/* { dg-options "-O2 -fstrict-flex-arrays=2 -Warray-bounds" } */
>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=2
>>>> -Warray-bounds" } */
>>>>
>>>> struct trailing_array_1 {
>>>> int a;
>>>> @@ -32,7 +32,9 @@ void __attribute__((__noinline__)) stuff(
>>>> struct trailing_array_4 *trailing_flex)
>>>> {
>>>> normal->c[5] = 5; /*{ dg-warning "array subscript 5 is above
>>>> array bounds of" } */
>>>> + /*{ dg-warning "should not be used as a
>>>> flexible array member for level 1 and above" "" { target *-*-* } .-1 } */
>>>> trailing_1->c[2] = 2; /* { dg-warning "array subscript 2 is above array
>>>> bounds of" } */
>>>> + /* { dg-warning "should not be used as a
>>>> flexible array member for level 2 and above" "" { target *-*-* } .-1 } */
>>>> trailing_0->c[1] = 1; /* { dg-bogus "array subscript " } */
>>>> trailing_flex->c[10] = 10; /* { dg-bogus "array subscript " } */
>>>>
>>>> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-3.c
>>>> b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-3.c
>>>> index e3273714e8b..25b903f2615 100644
>>>> --- a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-3.c
>>>> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-3.c
>>>> @@ -1,6 +1,6 @@
>>>> -/* Test -fstrict-flex-arrays + -Warray-bounds. */
>>>> +/* Test -fstrict-flex-arrays + -Warray-bounds + -Wstrict-flex-arrays. */
>>>> /* { dg-do compile } */
>>>> -/* { dg-options "-O2 -fstrict-flex-arrays=3 -Warray-bounds" } */
>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=3
>>>> -Warray-bounds" } */
>>>>
>>>> struct trailing_array_1 {
>>>> int a;
>>>> @@ -32,8 +32,11 @@ void __attribute__((__noinline__)) stuff(
>>>> struct trailing_array_4 *trailing_flex)
>>>> {
>>>> normal->c[5] = 5; /*{ dg-warning "array subscript 5 is above
>>>> array bounds of" } */
>>>> + /*{ dg-warning "should not be used as a
>>>> flexible array member for level 1 and above" "" { target *-*-* } .-1 } */
>>>> trailing_1->c[2] = 2; /*{ dg-warning "array subscript 2 is above array
>>>> bounds of" } */
>>>> + /* { dg-warning "should not be used as a
>>>> flexible array member for level 2 and above" "" { target *-*-* } .-1 } */
>>>> trailing_0->c[1] = 1; /*{ dg-warning "array subscript 1 is outside array
>>>> bounds of" } */
>>>> + /* { dg-warning "should not be used as a
>>>> flexible array member for level 3" "" { target *-*-* } .-1 } */
>>>> trailing_flex->c[10] = 10; /* { dg-bogus "array subscript" } */
>>>>
>>>> }
>>>> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-4.c
>>>> b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-4.c
>>>> index cabaea77dc2..5fc500a19ca 100644
>>>> --- a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-4.c
>>>> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-4.c
>>>> @@ -1,6 +1,6 @@
>>>> -/* Test -fstrict-flex-arrays + -Warray-bounds=2. */
>>>> +/* Test -fstrict-flex-arrays + -Warray-bounds=2 + -Wstrict-flex-arrays.
>>>> */
>>>> /* { dg-do compile } */
>>>> -/* { dg-options "-O2 -fstrict-flex-arrays=1 -Warray-bounds=2" } */
>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=1
>>>> -Warray-bounds=2" } */
>>>>
>>>> struct trailing_array_1 {
>>>> int a;
>>>> @@ -32,6 +32,7 @@ void __attribute__((__noinline__)) stuff(
>>>> struct trailing_array_4 *trailing_flex)
>>>> {
>>>> normal->c[5] = 5; /*{ dg-warning "array subscript 5 is above
>>>> array bounds of" } */
>>>> + /*{ dg-warning "should not be used as a
>>>> flexible array member for level 1 and above" "" { target *-*-* } .-1 } */
>>>> trailing_1->c[2] = 2; /* { dg-bogus "array subscript " } */
>>>> trailing_0->c[1] = 1; /* { dg-bogus "array subscript " } */
>>>> trailing_flex->c[10] = 10; /* { dg-bogus "array subscript " } */
>>>> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-5.c
>>>> b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-5.c
>>>> index 8b7db6e4f39..30bb4ca8832 100644
>>>> --- a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-5.c
>>>> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-5.c
>>>> @@ -1,6 +1,6 @@
>>>> -/* Test -fstrict-flex-arrays + -Warray-bounds=2. */
>>>> +/* Test -fstrict-flex-arrays + -Warray-bounds=2 + -Wstrict-flex-arrays.
>>>> */
>>>> /* { dg-do compile } */
>>>> -/* { dg-options "-O2 -fstrict-flex-arrays=2 -Warray-bounds=2" } */
>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=2
>>>> -Warray-bounds=2" } */
>>>>
>>>> struct trailing_array_1 {
>>>> int a;
>>>> @@ -32,7 +32,9 @@ void __attribute__((__noinline__)) stuff(
>>>> struct trailing_array_4 *trailing_flex)
>>>> {
>>>> normal->c[5] = 5; /*{ dg-warning "array subscript 5 is above array
>>>> bounds of" } */
>>>> + /*{ dg-warning "should not be used as a
>>>> flexible array member for level 1 and above" "" { target *-*-* } .-1 } */
>>>> trailing_1->c[2] = 2; /*{ dg-warning "array subscript 2 is above array
>>>> bounds of" } */
>>>> + /* { dg-warning "should not be used as a
>>>> flexible array member for level 2 and above" "" { target *-*-* } .-1 } */
>>>> trailing_0->c[1] = 1; /* { dg-bogus "array subscript " } */
>>>> trailing_flex->c[10] = 10; /* { dg-bogus "array subscript " } */
>>>>
>>>> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-6.c
>>>> b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-6.c
>>>> index 035bf481396..e847a44516e 100644
>>>> --- a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-6.c
>>>> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-6.c
>>>> @@ -1,6 +1,6 @@
>>>> -/* Test -fstrict-flex-arrays + -Warray-bounds=2. */
>>>> +/* Test -fstrict-flex-arrays + -Warray-bounds=2 + -Wstrict-flex-arrays.
>>>> */
>>>> /* { dg-do compile } */
>>>> -/* { dg-options "-O2 -fstrict-flex-arrays=3 -Warray-bounds=2" } */
>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=3
>>>> -Warray-bounds=2" } */
>>>>
>>>> struct trailing_array_1 {
>>>> int a;
>>>> @@ -32,8 +32,11 @@ void __attribute__((__noinline__)) stuff(
>>>> struct trailing_array_4 *trailing_flex)
>>>> {
>>>> normal->c[5] = 5; /*{ dg-warning "array subscript 5 is above
>>>> array bounds of" } */
>>>> + /*{ dg-warning "should not be used as a
>>>> flexible array member for level 1 and above" "" { target *-*-* } .-1 } */
>>>> trailing_1->c[2] = 2; /*{ dg-warning "array subscript 2 is above array
>>>> bounds of" } */
>>>> + /* { dg-warning "should not be used as a
>>>> flexible array member for level 2 and above" "" { target *-*-* } .-1 } */
>>>> trailing_0->c[1] = 1; /*{ dg-warning "array subscript 1 is outside array
>>>> bounds of" } */
>>>> + /* { dg-warning "should not be used as a
>>>> flexible array member for level 3" "" { target *-*-* } .-1 } */
>>>> trailing_flex->c[10] = 10; /* { dg-bogus "array subscript " } */
>>>>
>>>> }
>>>> diff --git a/gcc/testsuite/gcc.dg/Wstrict-flex-arrays-2.c
>>>> b/gcc/testsuite/gcc.dg/Wstrict-flex-arrays-2.c
>>>> new file mode 100644
>>>> index 00000000000..2e241f96208
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/gcc.dg/Wstrict-flex-arrays-2.c
>>>> @@ -0,0 +1,39 @@
>>>> +/* Test -Wstrict-flex-arrays. */
>>>> +/* { dg-do compile } */
>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=2" } */
>>>> +
>>>> +struct trailing_array_1 {
>>>> + int a;
>>>> + int b;
>>>> + int c[4];
>>>> +};
>>>> +
>>>> +struct trailing_array_2 {
>>>> + int a;
>>>> + int b;
>>>> + int c[1];
>>>> +};
>>>> +
>>>> +struct trailing_array_3 {
>>>> + int a;
>>>> + int b;
>>>> + int c[0];
>>>> +};
>>>> +struct trailing_array_4 {
>>>> + int a;
>>>> + int b;
>>>> + int c[];
>>>> +};
>>>> +
>>>> +void __attribute__((__noinline__)) stuff(
>>>> + struct trailing_array_1 *normal,
>>>> + struct trailing_array_2 *trailing_1,
>>>> + struct trailing_array_3 *trailing_0,
>>>> + struct trailing_array_4 *trailing_flex)
>>>> +{
>>>> + normal->c[5] = 5; /*{ dg-warning "should not be used as a
>>>> flexible array member for level 1 and above" } */
>>>> + trailing_1->c[2] = 2; /* { dg-warning "should not be used as a
>>>> flexible array member for level 2 and above" } */
>>>> + trailing_0->c[1] = 1; /* { dg-bogus "should not be used as a flexible
>>>> array member for level 2 and above" } */
>>>> + trailing_flex->c[10] = 10; /* { dg-bogus "should not be used as a
>>>> flexible array member for level 2 and above" } */
>>>> +
>>>> +}
>>>> diff --git a/gcc/testsuite/gcc.dg/Wstrict-flex-arrays-3.c
>>>> b/gcc/testsuite/gcc.dg/Wstrict-flex-arrays-3.c
>>>> new file mode 100644
>>>> index 00000000000..97eb65ba0a9
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/gcc.dg/Wstrict-flex-arrays-3.c
>>>> @@ -0,0 +1,39 @@
>>>> +/* Test -Wstrict-flex-arrays. */
>>>> +/* { dg-do compile } */
>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=3" } */
>>>> +
>>>> +struct trailing_array_1 {
>>>> + int a;
>>>> + int b;
>>>> + int c[4];
>>>> +};
>>>> +
>>>> +struct trailing_array_2 {
>>>> + int a;
>>>> + int b;
>>>> + int c[1];
>>>> +};
>>>> +
>>>> +struct trailing_array_3 {
>>>> + int a;
>>>> + int b;
>>>> + int c[0];
>>>> +};
>>>> +struct trailing_array_4 {
>>>> + int a;
>>>> + int b;
>>>> + int c[];
>>>> +};
>>>> +
>>>> +void __attribute__((__noinline__)) stuff(
>>>> + struct trailing_array_1 *normal,
>>>> + struct trailing_array_2 *trailing_1,
>>>> + struct trailing_array_3 *trailing_0,
>>>> + struct trailing_array_4 *trailing_flex)
>>>> +{
>>>> + normal->c[5] = 5; /*{ dg-warning "should not be used as a
>>>> flexible array member for level 1 and above" } */
>>>> + trailing_1->c[2] = 2; /* { dg-warning "should not be used as a
>>>> flexible array member for level 2 and above" } */
>>>> + trailing_0->c[1] = 1; /* { dg-warning "should not be used as a
>>>> flexible array member for level 3" } */
>>>> + trailing_flex->c[10] = 10; /* { dg-bogus "should not be used as a
>>>> flexible array member for level 3" } */
>>>> +
>>>> +}
>>>> diff --git a/gcc/testsuite/gcc.dg/Wstrict-flex-arrays.c
>>>> b/gcc/testsuite/gcc.dg/Wstrict-flex-arrays.c
>>>> new file mode 100644
>>>> index 00000000000..110fdc72778
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/gcc.dg/Wstrict-flex-arrays.c
>>>> @@ -0,0 +1,39 @@
>>>> +/* Test -Wstrict-flex-arrays. */
>>>> +/* { dg-do compile } */
>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=1" } */
>>>> +
>>>> +struct trailing_array_1 {
>>>> + int a;
>>>> + int b;
>>>> + int c[4];
>>>> +};
>>>> +
>>>> +struct trailing_array_2 {
>>>> + int a;
>>>> + int b;
>>>> + int c[1];
>>>> +};
>>>> +
>>>> +struct trailing_array_3 {
>>>> + int a;
>>>> + int b;
>>>> + int c[0];
>>>> +};
>>>> +struct trailing_array_4 {
>>>> + int a;
>>>> + int b;
>>>> + int c[];
>>>> +};
>>>> +
>>>> +void __attribute__((__noinline__)) stuff(
>>>> + struct trailing_array_1 *normal,
>>>> + struct trailing_array_2 *trailing_1,
>>>> + struct trailing_array_3 *trailing_0,
>>>> + struct trailing_array_4 *trailing_flex)
>>>> +{
>>>> + normal->c[5] = 5; /*{ dg-warning "should not be used as a
>>>> flexible array member for level 1 and above" } */
>>>> + trailing_1->c[2] = 2; /* { dg-bogus "should not be used as a flexible
>>>> array member for level 1 and above" } */
>>>> + trailing_0->c[1] = 1; /* { dg-bogus "should not be used as a flexible
>>>> array member for level 1 and above" } */
>>>> + trailing_flex->c[10] = 10; /* { dg-bogus "should not be used as a
>>>> flexible array member for level 1 and above" } */
>>>> +
>>>> +}
>>>> diff --git a/gcc/tree-vrp.cc b/gcc/tree-vrp.cc
>>>> index 3846dc1d849..e6c6c5a301d 100644
>>>> --- a/gcc/tree-vrp.cc
>>>> +++ b/gcc/tree-vrp.cc
>>>> @@ -1087,7 +1087,7 @@ execute_ranger_vrp (struct function *fun, bool
>>>> warn_array_bounds_p,
>>>> if (dump_file && (dump_flags & TDF_DETAILS))
>>>> ranger->dump (dump_file);
>>>>
>>>> - if (warn_array_bounds && warn_array_bounds_p)
>>>> + if ((warn_array_bounds || warn_strict_flex_arrays) &&
>>>> warn_array_bounds_p)
>>>> {
>>>> // Set all edges as executable, except those ranger says aren't.
>>>> int non_exec_flag = ranger->non_executable_edge_flag;
>>>> --
>>>> 2.31.1
>>>>
>>>
>>>
>>
>> --
>> Richard Biener <rguent...@suse.de>
>> SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
>> Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
>> HRB 36809 (AG Nuernberg)
