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.
> 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.
In particular I find, say, -fstrict-flex-arrays=2 -Wstrict-flex-arrays=1
hardly useful.
But I'm interested in other opinions.
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)
