[PATCH] Don't allow mask/sse/mmx mov in TLS code sequences.

Uros Bizjak ubizjak@gmail.com
Fri Nov 19 07:50:23 GMT 2021


On Fri, Nov 19, 2021 at 2:14 AM liuhongt <hongtao.liu@intel.com> wrote:
>
> >Why is the above declared as a special memory constraint? Also the
> Change to define_memory_constraint since it's ok for
> reload can make them match by converting the operand to the form
> ‘(mem (reg X))’.where X is a base register (from the register class specified
> by BASE_REG_CLASS
>
> >predicate comment is missing and the description should say something
> >like:
> >
> >@internal TLS address that allows insn using non-integer registers
> Changed.
>
> >I think it is better to avoid negative logic. So, something like
> >
> >Return true if the TLS address requires insn using integer registers.
> >
> >bool
> >ix86_gpr_tls_address_pattern_p
> >
> >(and use not in the predicate)
>
> Changed.
>
> >> +{
> >> +  gcc_assert (MEM_P (mem));
> >> +
> >> +  rtx addr = XEXP (mem, 0);
> >> +  subrtx_var_iterator::array_type array;
> >> +  FOR_EACH_SUBRTX_VAR (iter, array, addr, ALL)
> >> +    {
> >> +      rtx op = *iter;
> >> +      if (GET_CODE (op) == UNSPEC)
> >> +       switch (XINT (op, 1))
> >> +         {
> >> +         case UNSPEC_GOTNTPOFF:
> >> +           return false;
> >> +         case UNSPEC_TPOFF:
> >> +           if (!TARGET_64BIT)
> >> +             return false;
> >> +           break;
> >> +         default:
> >> +           break;
> >> +         }
> >> +      /* Should iter.skip_subrtxes ();
> >> +        if there's no inner UNSPEC in addr???.  */
>
> >You should figure the above before submitting the patch.
> ix86_print_operand_address_as shows there could be inner UNSPEC in addr, so
> remove comments.
>
> >Can you please minimize the testcase?
> Done;
>
> As change in assembler, refer to [1], this patch disallow mask/sse/mmx
> mov in TLS code sequences which require integer MOV instructions.
>
> [1] https://sourceware.org/git/?p=binutils-gdb.git;a=patch;h=d7e3e627027fcf37d63e284144fe27ff4eba36b5
>
> gcc/ChangeLog:
>
>         PR target/103275
>         * config/i386/i386-protos.h (ix86_gpr_tls_address_pattern_p):
>         Declare.
>         * config/i386/i386.c (ix86_gpr_tls_address_pattern_p): New
>         function.
>         * config/i386/i386.md (*movsi_internal): Don't allow
>         mask/sse/mmx move in TLS code sequences.
>         (*movdi_internal): Ditto.
>
> gcc/testsuite/ChangeLog:
>
>         * gcc.target/i386/pr103275.c: New test.

OK, with a small comment adjustment below.

Thanks,
Uros.

> ---
>  gcc/config/i386/constraints.md           |  5 ++
>  gcc/config/i386/i386-protos.h            |  1 +
>  gcc/config/i386/i386.c                   | 32 +++++++++
>  gcc/config/i386/i386.md                  | 18 ++---
>  gcc/testsuite/gcc.target/i386/pr103275.c | 83 ++++++++++++++++++++++++
>  5 files changed, 130 insertions(+), 9 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr103275.c
>
> diff --git a/gcc/config/i386/constraints.md b/gcc/config/i386/constraints.md
> index eaa582d2055..15c5950ee6f 100644
> --- a/gcc/config/i386/constraints.md
> +++ b/gcc/config/i386/constraints.md
> @@ -185,6 +185,11 @@ (define_special_memory_constraint "Bc"
>    (and (match_operand 0 "memory_operand")
>         (match_test "constant_address_p (XEXP (op, 0))")))
>
> +(define_memory_constraint "Bk"
> +  "@internal TLS address that allows insn using non-integer registers."
> +  (and (match_operand 0 "memory_operand")
> +       (not (match_test "ix86_gpr_tls_address_pattern_p (op)"))))
> +
>  (define_special_memory_constraint "Bn"
>    "@internal Memory operand without REX prefix."
>    (match_operand 0 "norex_memory_operand"))
> diff --git a/gcc/config/i386/i386-protos.h b/gcc/config/i386/i386-protos.h
> index 7782cf1163f..941e91636d8 100644
> --- a/gcc/config/i386/i386-protos.h
> +++ b/gcc/config/i386/i386-protos.h
> @@ -240,6 +240,7 @@ extern unsigned int ix86_get_callcvt (const_tree);
>  #endif
>
>  extern rtx ix86_tls_module_base (void);
> +extern bool ix86_gpr_tls_address_pattern_p (rtx);
>  extern bool ix86_tls_address_pattern_p (rtx);
>  extern rtx ix86_rewrite_tls_address (rtx);
>
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index 42c47d2b12b..68079e4230e 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -11468,6 +11468,38 @@ legitimize_tls_address (rtx x, enum tls_model model, bool for_mov)
>    return dest;
>  }
>
> +/* Return true if the TLS address requires insn using integer registers.
> +   NB: it's different from ix86_tls_address_pattern_p since it also matchs
> +   gottpoff/gotntpoff.

The above NB comment is not needed, the fact is obvious from the code.

> +   It's used to prevent KMOV/VMOV in TLS code sequences which require integer
> +   MOV instructions, refer to PR103275.  */
> +bool
> +ix86_gpr_tls_address_pattern_p (rtx mem)
> +{
> +  gcc_assert (MEM_P (mem));
> +
> +  rtx addr = XEXP (mem, 0);
> +  subrtx_var_iterator::array_type array;
> +  FOR_EACH_SUBRTX_VAR (iter, array, addr, ALL)
> +    {
> +      rtx op = *iter;
> +      if (GET_CODE (op) == UNSPEC)
> +       switch (XINT (op, 1))
> +         {
> +         case UNSPEC_GOTNTPOFF:
> +           return true;
> +         case UNSPEC_TPOFF:
> +           if (!TARGET_64BIT)
> +             return true;
> +           break;
> +         default:
> +           break;
> +         }
> +    }
> +
> +  return false;
> +}
> +
>  /* Return true if OP refers to a TLS address.  */
>  bool
>  ix86_tls_address_pattern_p (rtx op)
> diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
> index 97325e38676..82b85b26059 100644
> --- a/gcc/config/i386/i386.md
> +++ b/gcc/config/i386/i386.md
> @@ -2085,9 +2085,9 @@ (define_split
>
>  (define_insn "*movdi_internal"
>    [(set (match_operand:DI 0 "nonimmediate_operand"
> -    "=r  ,o  ,r,r  ,r,m ,*y,*y,?*y,?m,?r,?*y,*v,*v,*v,m ,m,?r ,?*Yd,?r,?*v,?*y,?*x,*k,*k ,*r,*m,*k")
> +    "=r  ,o  ,r,r  ,r,m ,*y,*y,?*y,?m,?r,?*y,*v,*v,*v,m ,m,?r ,?*Yd,?r,?*v,?*y,?*x,*k,*k,*k ,*r,*m,*k")
>         (match_operand:DI 1 "general_operand"
> -    "riFo,riF,Z,rem,i,re,C ,*y,m  ,*y,*y,r  ,C ,*v,m ,*v,v,*Yd,r   ,*v,r  ,*x ,*y ,*r,*km,*k,*k,CBC"))]
> +    "riFo,riF,Z,rem,i,re,C ,*y,Bk ,*y,*y,r  ,C ,*v,Bk,*v,v,*Yd,r   ,*v,r  ,*x ,*y ,*r,*k,*Bk,*k,*k,CBC"))]
>    "!(MEM_P (operands[0]) && MEM_P (operands[1]))
>     && ix86_hardreg_mov_ok (operands[0], operands[1])"
>  {
> @@ -2149,7 +2149,7 @@ (define_insn "*movdi_internal"
>    [(set (attr "isa")
>       (cond [(eq_attr "alternative" "0,1,17,18")
>               (const_string "nox64")
> -           (eq_attr "alternative" "2,3,4,5,10,11,23,25")
> +           (eq_attr "alternative" "2,3,4,5,10,11,23,26")
>               (const_string "x64")
>             (eq_attr "alternative" "19,20")
>               (const_string "x64_sse2")
> @@ -2170,9 +2170,9 @@ (define_insn "*movdi_internal"
>               (const_string "ssemov")
>             (eq_attr "alternative" "21,22")
>               (const_string "ssecvt")
> -           (eq_attr "alternative" "23,24,25,26")
> +           (eq_attr "alternative" "23,24,25,26,27")
>               (const_string "mskmov")
> -           (eq_attr "alternative" "27")
> +           (eq_attr "alternative" "28")
>               (const_string "msklog")
>             (and (match_operand 0 "register_operand")
>                  (match_operand 1 "pic_32bit_operand"))
> @@ -2306,9 +2306,9 @@ (define_peephole2
>
>  (define_insn "*movsi_internal"
>    [(set (match_operand:SI 0 "nonimmediate_operand"
> -    "=r,m ,*y,*y,?*y,?m,?r,?*y,*v,*v,*v,m ,?r,?*v,*k,*k ,*rm,*k")
> +    "=r,m ,*y,*y,?*y,?m,?r,?*y,*v,*v,*v,m ,?r,?*v,*k,*k ,*k,*rm,*k")
>         (match_operand:SI 1 "general_operand"
> -    "g ,re,C ,*y,m  ,*y,*y,r  ,C ,*v,m ,*v,*v,r  ,*r,*km,*k ,CBC"))]
> +    "g ,re,C ,*y,Bk ,*y,*y,r  ,C ,*v,Bk,*v,*v,r  ,*r,*k, *Bk,*k ,CBC"))]
>    "!(MEM_P (operands[0]) && MEM_P (operands[1]))
>     && ix86_hardreg_mov_ok (operands[0], operands[1])"
>  {
> @@ -2373,9 +2373,9 @@ (define_insn "*movsi_internal"
>               (const_string "sselog1")
>             (eq_attr "alternative" "9,10,11,12,13")
>               (const_string "ssemov")
> -           (eq_attr "alternative" "14,15,16")
> +           (eq_attr "alternative" "14,15,16,17")
>               (const_string "mskmov")
> -           (eq_attr "alternative" "17")
> +           (eq_attr "alternative" "18")
>               (const_string "msklog")
>             (and (match_operand 0 "register_operand")
>                  (match_operand 1 "pic_32bit_operand"))
> diff --git a/gcc/testsuite/gcc.target/i386/pr103275.c b/gcc/testsuite/gcc.target/i386/pr103275.c
> new file mode 100644
> index 00000000000..c93413f3cde
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr103275.c
> @@ -0,0 +1,83 @@
> +/* { dg-do compile { target ia32 } }  */
> +/* { dg-options "-O2 -march=tigerlake -fPIC" } */
> +/* { dg-final { scan-assembler-not {(?n)kmovd.*@gotntpoff} } }  */
> +
> +typedef unsigned short uint16_t;
> +typedef int int32_t;
> +typedef unsigned int uint32_t;
> +typedef unsigned char uint8_t;
> +
> +typedef uint32_t in_addr_t;
> +struct in_addr { in_addr_t s_addr; };
> +
> +extern __thread const uint16_t * __libc_tsd_CTYPE_B __attribute__ ((tls_model ("initial-exec")));
> +extern __thread int __libc_errno __attribute__ ((tls_model ("initial-exec")));
> +
> +extern unsigned long strtoul (const char*, char**, int);
> +extern uint32_t __bswap_32 (in_addr_t);
> +int
> +inet_aton_end (const char *cp, struct in_addr *addr, const char **endp)
> +{
> +  static const in_addr_t max[4] = { 0xffffffff, 0xffffff, 0xffff, 0xff };
> +  in_addr_t val;
> +  char c;
> +  union iaddr
> +  {
> +    uint8_t bytes[4];
> +    uint32_t word;
> +  } res;
> +  uint8_t *pp = res.bytes;
> +  int digit;
> +
> +  int saved_errno = __libc_errno;
> +  __libc_errno = 0;
> +  res.word = 0;
> +  c = *cp;
> +
> +  for (;;)
> +    {
> +      if (c < '0' || c > '9')
> +       goto ret_0;
> +      {
> +       char *endp;
> +       unsigned long ul = strtoul (cp, &endp, 0);
> +       if (ul == 0x7fffffffL && __libc_errno == 34)
> +         goto ret_0;
> +       if (ul > 0xfffffffful)
> +         goto ret_0;
> +       val = ul;
> +       digit = cp != endp;
> +       cp = endp;
> +      }
> +      c = *cp;
> +      if (c == '.')
> +       {
> +         if (pp > res.bytes + 2 || val > 0xff)
> +           goto ret_0;
> +         *pp++ = val;
> +         c = *++cp;
> +       }
> +      else
> +       break;
> +    }
> +
> +  if (!(__libc_tsd_CTYPE_B[(int)c] & 8192))
> +    goto ret_0;
> +
> +  if (!digit)
> +    goto ret_0;
> +
> +  if (val > max[pp - res.bytes])
> +    goto ret_0;
> +
> +  if (addr != 0)
> +    addr->s_addr = res.word | __bswap_32 (val);
> +  *endp = cp;
> +
> +  __libc_errno = saved_errno;
> +  return 1;
> +
> + ret_0:
> +  __libc_errno = saved_errno;
> +  return 0;
> +}
> --
> 2.18.1
>


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