> On Dec 15, 2022, at 2:47 AM, Richard Biener <rguent...@suse.de> wrote:
>
> On Wed, 14 Dec 2022, Qing Zhao wrote:
>
>> Hi, Richard,
>>
>> I guess that we now agreed on the following:
>>
>> “ 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”
>>
>> The only thing we didn’t decide is:
>>
>> A. Amend such new information to -Warray-bounds when -fstrict-flex-arrays=N
>> (N>0) specified.
>>
>> OR
>>
>> B. Issue such new information with a new warning option -Wstrict-flex-arrays
>> when -fstrict-flex-arrays=N (N>0) specified.
>>
>> My current patch implemented B.
>
> Plus it implements it to specify a different flex-array variant for
> the extra diagnostic.
Could you clarify a little bit on this? (Don’t quite understand…)
>
>> If you think A is better, I will change the patch as A.
>
> I would tend to A since, as I said, it's useful information that
> shouldn't be hidden and not adding an option removes odd combination
> possibilities such as -Wno-array-bounds -Wstrict-flex-arrays.
With current implementation, the above combination will ONLY report the misuse
of trailing array as flex-array. No out-of-bounds warnings issued.
> In particular I find, say, -fstrict-flex-arrays=2 -Wstrict-flex-arrays=1
> hardly useful.
The above combination will NOT happen, because there is NO level argument for
-Wstrict-flex-arrays.
The only combination will be: -fstrict-flex-arrays=N -Wstrict-flex-arrays
When N > 0, -Wstrict-flex-arrays will report any misuse of trailing arrays as
flexible array per the value of N.
>
> But I'm interested in other opinions.
Adding a separate -Wstrict-flex-arrays will provide users a choice to ONLY look
at the mis-use of trailing arrays as flex-arrays. Without this new option,
such information will be buried into tons of out-of-bounds messges.
I think this is the major benefit to have one separate new warning
-Wstrict-flex-arrays.
Do we need to provide the users this choice?
Thanks.
Qing
>
> Thanks,
> Richard.
>
>> Let me know your opinion.
>>
>> thanks.
>>
>> Qing
>>
>>
>>> 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?
>>> 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
>>>
>>> ? 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?
>>>
>>> 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)
>>
>>
>
> --
> 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)
