Ping.
This isn't a regression, but I think the fix is simple enough.
Thanks.
On 2/2/26 10:43, David Faust wrote:
> ctf_die_bitsize was reading DW_AT_byte_size or DW_AT_bit_size using
> AT_unsigned, which fails with an assert if the value is not constant.
> This can be the case with variable length vectors such as those used
> by aarch64 SVE, which CTF does not support.
>
> Check that the size is a constant before reading with AT_unsigned in
> ctf_die_bitsize, and return 0 if the entity size is variable.
> This change results in such vector types being emitted in CTF as
> unrepresentable types rather than causing an ICE.
>
> Tested on x86_64-linux-gnu host for aarch64-linux-gnu and native
> targets, ok for trunk?
>
> PR debug/114016
>
> gcc/
> * dwarf2ctf.cc (is_AT_unsigned): New static helper.
> (ctf_die_bitsize): Use it here before reading with AT_unsigned.
>
> gcc/testsuite/
> * gcc.dg/debug/ctf/pr114016.c: New test.
> ---
> gcc/dwarf2ctf.cc | 17 +++++++++++++----
> gcc/testsuite/gcc.dg/debug/ctf/pr114016.c | 7 +++++++
> 2 files changed, 20 insertions(+), 4 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/debug/ctf/pr114016.c
>
> diff --git a/gcc/dwarf2ctf.cc b/gcc/dwarf2ctf.cc
> index a561087b047..ef744e4d5ec 100644
> --- a/gcc/dwarf2ctf.cc
> +++ b/gcc/dwarf2ctf.cc
> @@ -201,10 +201,19 @@ gen_ctf_unknown_type (ctf_container_ref ctfc)
> return dtd;
> }
>
> +/* Return whether A can be read as AT_unsigned. */
> +
> +static bool
> +is_AT_unsigned (dw_attr_node *a)
> +{
> + return (AT_class (a) == dw_val_class_unsigned_const
> + || AT_class (a) == dw_val_class_unsigned_const_implicit);
> +}
> +
> /* Sizes of entities can be given in bytes or bits. This function
> abstracts this by returning the size in bits of the given entity.
> - If no DW_AT_byte_size nor DW_AT_bit_size are defined, this function
> - returns 0. */
> + If no DW_AT_byte_size nor DW_AT_bit_size are defined, or if the
> + size is variable, this function returns 0. */
>
> static unsigned HOST_WIDE_INT
> ctf_die_bitsize (dw_die_ref die)
> @@ -212,9 +221,9 @@ ctf_die_bitsize (dw_die_ref die)
> dw_attr_node *attr_byte_size = get_AT (die, DW_AT_byte_size);
> dw_attr_node *attr_bit_size = get_AT (die, DW_AT_bit_size);
>
> - if (attr_bit_size)
> + if (attr_bit_size && is_AT_unsigned (attr_bit_size))
> return AT_unsigned (attr_bit_size);
> - else if (attr_byte_size)
> + else if (attr_byte_size && is_AT_unsigned (attr_byte_size))
> return (AT_unsigned (attr_byte_size) * 8);
> else
> return 0;
> diff --git a/gcc/testsuite/gcc.dg/debug/ctf/pr114016.c
> b/gcc/testsuite/gcc.dg/debug/ctf/pr114016.c
> new file mode 100644
> index 00000000000..5344b293e32
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/debug/ctf/pr114016.c
> @@ -0,0 +1,7 @@
> +/* PR debug/114016
> + CTF generation for variable length vector using aarch64 SVE. */
> +/* { dg-do compile { target aarch64-*-* } } */
> +/* { dg-options "-march=armv8.2-a+sve -gctf" } */
> +
> +#pragma GCC aarch64 "arm_sve.h"
> +svuint64x4_t *p;
