[PATCH, i386, Pointer Bounds Checker 34/x] Vararg functions support

Ilya Enkovich enkovich.gnu@gmail.com
Mon Sep 15 07:17:00 GMT 2014


Ping

2014-06-11 18:06 GMT+04:00 Ilya Enkovich <enkovich.gnu@gmail.com>:
> Hi,
>
> This patch introduces initialization of incoming bounds for vararg function on i386 target.
>
> Bootstrapped and tested on linux-x86_64.
>
> Thanks,
> Ilya
> --
> gcc/
>
> 2014-06-11  Ilya Enkovich  <ilya.enkovich@intel.com>
>
>         * config/i386/i386.c (ix86_setup_incoming_varargs): New.
>         (ix86_va_start): Initialize bounds for pointers in va_list.
>         (TARGET_SETUP_INCOMING_VARARG_BOUNDS): New.
>
>
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index a67e6e7..c520f26 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -8456,6 +8456,72 @@ ix86_setup_incoming_varargs (cumulative_args_t cum_v, enum machine_mode mode,
>      setup_incoming_varargs_64 (&next_cum);
>  }
>
> +static void
> +ix86_setup_incoming_vararg_bounds (cumulative_args_t cum_v,
> +                                  enum machine_mode mode,
> +                                  tree type,
> +                                  int *pretend_size ATTRIBUTE_UNUSED,
> +                                  int no_rtl)
> +{
> +  CUMULATIVE_ARGS *cum = get_cumulative_args (cum_v);
> +  CUMULATIVE_ARGS next_cum;
> +  tree fntype;
> +  rtx save_area;
> +  int bnd_reg, i, max;
> +
> +  gcc_assert (!no_rtl);
> +
> +  if (!TARGET_64BIT)
> +    return;
> +
> +  fntype = TREE_TYPE (current_function_decl);
> +
> +  /* For varargs, we do not want to skip the dummy va_dcl argument.
> +     For stdargs, we do want to skip the last named argument.  */
> +  next_cum = *cum;
> +  if (stdarg_p (fntype))
> +    ix86_function_arg_advance (pack_cumulative_args (&next_cum), mode, type,
> +                              true);
> +  if (cum->call_abi == MS_ABI)
> +    return;
> +
> +  save_area = frame_pointer_rtx;
> +
> +  max = cum->regno + cfun->va_list_gpr_size / UNITS_PER_WORD;
> +  if (max > X86_64_REGPARM_MAX)
> +    max = X86_64_REGPARM_MAX;
> +
> +  bnd_reg = cum->bnd_regno + cum->force_bnd_pass;
> +  if (chkp_function_instrumented_p (current_function_decl))
> +    for (i = cum->regno; i < max; i++)
> +      {
> +       rtx addr = plus_constant (Pmode, save_area, i * UNITS_PER_WORD);
> +       rtx reg = gen_rtx_REG (DImode,
> +                              x86_64_int_parameter_registers[i]);
> +       rtx ptr = reg;
> +       rtx bounds;
> +
> +       if (bnd_reg <= LAST_BND_REG)
> +         bounds = gen_rtx_REG (BNDmode, bnd_reg);
> +       else
> +         {
> +           rtx ldx_addr = plus_constant (Pmode, arg_pointer_rtx,
> +                                         (LAST_BND_REG - bnd_reg) * 8);
> +           bounds = gen_reg_rtx (BNDmode);
> +           emit_insn (TARGET_64BIT
> +                      ? gen_bnd64_ldx (bounds, ldx_addr, ptr)
> +                      : gen_bnd32_ldx (bounds, ldx_addr, ptr));
> +         }
> +
> +       emit_insn (TARGET_64BIT
> +                  ? gen_bnd64_stx (addr, ptr, bounds)
> +                  : gen_bnd32_stx (addr, ptr, bounds));
> +
> +       bnd_reg++;
> +      }
> +}
> +
> +
>  /* Checks if TYPE is of kind va_list char *.  */
>
>  static bool
> @@ -8478,7 +8544,7 @@ ix86_va_start (tree valist, rtx nextarg)
>  {
>    HOST_WIDE_INT words, n_gpr, n_fpr;
>    tree f_gpr, f_fpr, f_ovf, f_sav;
> -  tree gpr, fpr, ovf, sav, t;
> +  tree gpr, fpr, ovf, sav, t, t1;
>    tree type;
>    rtx ovf_rtx;
>
> @@ -8529,6 +8595,13 @@ ix86_va_start (tree valist, rtx nextarg)
>                                crtl->args.arg_offset_rtx,
>                                NULL_RTX, 0, OPTAB_LIB_WIDEN);
>           convert_move (va_r, next, 0);
> +
> +         /* Store zero bounds for va_list.  */
> +         if (chkp_function_instrumented_p (current_function_decl))
> +           chkp_expand_bounds_reset_for_mem (valist,
> +                                             make_tree (TREE_TYPE (valist),
> +                                                        next));
> +
>         }
>        return;
>      }
> @@ -8582,10 +8655,15 @@ ix86_va_start (tree valist, rtx nextarg)
>    t = make_tree (type, ovf_rtx);
>    if (words != 0)
>      t = fold_build_pointer_plus_hwi (t, words * UNITS_PER_WORD);
> +  t1 = t;
>    t = build2 (MODIFY_EXPR, type, ovf, t);
>    TREE_SIDE_EFFECTS (t) = 1;
>    expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
>
> +  /* Store zero bounds for overflow area pointer.  */
> +  if (chkp_function_instrumented_p (current_function_decl))
> +    chkp_expand_bounds_reset_for_mem (ovf, t1);
> +
>    if (ix86_varargs_gpr_size || ix86_varargs_fpr_size)
>      {
>        /* Find the register save area.
> @@ -8594,9 +8672,14 @@ ix86_va_start (tree valist, rtx nextarg)
>        t = make_tree (type, frame_pointer_rtx);
>        if (!ix86_varargs_gpr_size)
>         t = fold_build_pointer_plus_hwi (t, -8 * X86_64_REGPARM_MAX);
> +      t1 = t;
>        t = build2 (MODIFY_EXPR, type, sav, t);
>        TREE_SIDE_EFFECTS (t) = 1;
>        expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
> +
> +      /* Store zero bounds for save area pointer.  */
> +      if (chkp_function_instrumented_p (current_function_decl))
> +       chkp_expand_bounds_reset_for_mem (sav, t1);
>      }
>  }
>
> @@ -48057,6 +48140,9 @@ ix86_initialize_bounds (tree var, tree lb, tree ub, tree *stmts)
>  #undef TARGET_CHKP_INITIALIZE_BOUNDS
>  #define TARGET_CHKP_INITIALIZE_BOUNDS ix86_initialize_bounds
>
> +#undef TARGET_SETUP_INCOMING_VARARG_BOUNDS
> +#define TARGET_SETUP_INCOMING_VARARG_BOUNDS ix86_setup_incoming_vararg_bounds
> +
>  struct gcc_target targetm = TARGET_INITIALIZER;
>
>  #include "gt-i386.h"



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