Re: [PATCH] Update array address space in c_build_qualified_type

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

On Wed, Jun 21, 2023 at 7:57 AM <SenthilKumar.Selvaraj@microchip.com> wrote:
>
> Hi,
>
>   When c-typeck.cc:c_build_qualified_type builds an array type
>   from its element type, it does not copy the address space of
>   the element type to the array type itself. This is unlike
>   tree.cc:build_array_type_1, which explicitly does
>
> TYPE_ADDR_SPACE (t) = TYPE_ADDR_SPACE (elt_type);
>
>   This causes the ICE described in
>   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86869.
>
> struct S {
>   char y[2];
> };
>
> extern const __memx  struct S *s;
>
> extern void bar(const __memx void*);
>
> void foo(void) {
>   bar(&s->y);
> }
>
>   build_component_ref calls c_build_qualified_type, passing in the
>   array type and quals including the address space (ADDR_SPACE_MEMX
>   in this case). Because of this missing address space copy, the
>   returned array type remains in the generic address space.  Later
>   down the line, expand_expr_addr_expr detects the mismatch in
>   address space/mode and tries to convert, and that leads to the
>   ICE described in the bug.
>
>   This patch sets the address space of the array type to that of the
>   element type.
>
>   Regression tests for avr look ok. Ok for trunk?

The patch looks OK to me but please let a C frontend maintainer
double-check (I've CCed Joseph for this).

Thanks,
Richard.

> Regards
> Senthil
>
>         PR 86869
>
> gcc/c/ChangeLog:
>
>         * c-typeck.cc (c_build_qualified_type): Set
>         TYPE_ADDR_SPACE for ARRAY_TYPE.
>
> gcc/testsuite/ChangeLog:
>
>         * gcc.target/avr/pr86869.c: New test.
>
> diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
> index 22e240a3c2a..d4ab1d1bd46 100644
> --- a/gcc/c/c-typeck.cc
> +++ b/gcc/c/c-typeck.cc
> @@ -16284,6 +16284,7 @@ c_build_qualified_type (tree type, int type_quals, tree orig_qual_type,
>
>           t = build_variant_type_copy (type);
>           TREE_TYPE (t) = element_type;
> +         TYPE_ADDR_SPACE (t) = TYPE_ADDR_SPACE (element_type);
>
>            if (TYPE_STRUCTURAL_EQUALITY_P (element_type)
>                || (domain && TYPE_STRUCTURAL_EQUALITY_P (domain)))
> diff --git a/gcc/testsuite/gcc.target/avr/pr86869.c b/gcc/testsuite/gcc.target/avr/pr86869.c
> new file mode 100644
> index 00000000000..54cd984276e
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/avr/pr86869.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile } */
> +/* { dg-options "-std=gnu99" } */
> +
> +extern void bar(const __memx void* p);
> +
> +struct S {
> +  char y[2];
> +};
> +extern const __memx struct S *s;
> +
> +void foo(void) {
> +  bar(&s->y);
> +}