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Re: [PATCH V5 2/3] Add AVX512 register support to gdbserver.
- From: Andreas Arnez <arnez at linux dot vnet dot ibm dot com>
- To: Michael Sturm <michael dot sturm at intel dot com>
- Cc: palves at redhat dot com, eliz at gnu dot org, mark dot kettenis at xs4all dot nl, walfred dot tedeschi at intel dot com, gdb-patches at sourceware dot org
- Date: Fri, 21 Nov 2014 11:21:11 +0100
- Subject: Re: [PATCH V5 2/3] Add AVX512 register support to gdbserver.
- Authentication-results: sourceware.org; auth=none
- References: <1398258160-9070-1-git-send-email-michael dot sturm at intel dot com> <1398258160-9070-3-git-send-email-michael dot sturm at intel dot com>
Hi,
While building GDB I encountered a gcc warning (array subscript above
array bounds) and tracked it down to the patch below.
On Wed, Apr 23 2014, Michael Sturm wrote:
> # Linux object files. This is so we don't have to repeat
> diff --git a/gdb/gdbserver/i387-fp.c b/gdb/gdbserver/i387-fp.c
> index e655f74..c2d0bdf 100644
> --- a/gdb/gdbserver/i387-fp.c
> +++ b/gdb/gdbserver/i387-fp.c
> @@ -22,6 +22,11 @@
>
> static const int num_mpx_bnd_registers = 4;
> static const int num_mpx_cfg_registers = 2;
> +static const int num_avx512_k_registers = 8;
> +static const int num_avx512_zmmh_low_registers = 16;
> +static const int num_avx512_zmmh_high_registers = 16;
> +static const int num_avx512_ymmh_registers = 16;
> +static const int num_avx512_xmm_registers = 16;
>
> /* Note: These functions preserve the reserved bits in control registers.
> However, gdbserver promptly throws away that information. */
> @@ -120,6 +125,17 @@ struct i387_xsave {
> /* Space for 2 MPX configuration registers of 64 bits
> plus reserved space. */
> unsigned char mpx_cfg_space[16];
> +
> + unsigned char reserved5[48];
> +
> + /* Space for 8 OpMask register values of 64 bits. */
> + unsigned char k_space[64];
> +
> + /* Space for 16 256-bit zmm0-15. */
> + unsigned char zmmh_low_space[512];
> +
> + /* Space for 16 512-bit zmm16-31 values. */
> + unsigned char zmmh_high_space[1024];
> };
>
> [...]
> +
> + /* Check if any of ZMM16H-ZMM31H registers are changed. */
> + if ((x86_xcr0 & I386_XSTATE_ZMM))
> + {
> + int zmm16h_regnum = find_regno (regcache->tdesc, "zmm16h");
> +
> + for (i = 0; i < num_avx512_zmmh_high_registers; i++)
> + {
> + collect_register (regcache, i + zmm16h_regnum, raw);
> + p = ((char *) &fp->zmmh_low_space[0]) + 32 + i * 64;
^^^^^^^^^^^^^^
Should this really mean 'zmm_high_space'?
> + if (memcmp (raw, p, 32) != 0)
The warning occurs for this memcmp().
> + {
> + xstate_bv |= I386_XSTATE_ZMM;
> + memcpy (p, raw, 32);
> + }
> + }
> + }