Re: [PATCH, MPX, 2/X] Pointers Checker [10/25] Calls copy and verification

[Ilya Enkovich <enkovich dot gnu at gmail dot com>]

2013/11/4 Richard Biener <richard.guenther@gmail.com>:
> On Thu, Oct 31, 2013 at 10:24 AM, Ilya Enkovich <enkovich.gnu@gmail.com> wrote:
>> Hi,
>>
>> Here is a patch to support of instrumented code in calls verifiers and calls copy with skipped args.
>>
>> Thanks,
>> Ilya
>> --
>>
>> gcc/
>>
>> 2013-10-29  Ilya Enkovich  <ilya.enkovich@intel.com>
>>
>>         * cgraph.c (gimple_check_call_args): Handle bound args.
>>         * gimple.c (gimple_call_copy_skip_args): Likewise.
>>         (validate_call): Likewise.
>>
>>
>> diff --git a/gcc/cgraph.c b/gcc/cgraph.c
>> index 52d9ab0..9d7ae85 100644
>> --- a/gcc/cgraph.c
>> +++ b/gcc/cgraph.c
>> @@ -3030,40 +3030,54 @@ gimple_check_call_args (gimple stmt, tree fndecl, bool args_count_match)
>>      {
>>        for (i = 0, p = DECL_ARGUMENTS (fndecl);
>>            i < nargs;
>> -          i++, p = DECL_CHAIN (p))
>> +          i++)
>>         {
>> -         tree arg;
>> +         tree arg = gimple_call_arg (stmt, i);
>> +
>> +         /* Skip bound args inserted by Pointer Bounds Checker.  */
>> +         if (POINTER_BOUNDS_P (arg))
>> +           continue;
>> +
>>           /* We cannot distinguish a varargs function from the case
>>              of excess parameters, still deferring the inlining decision
>>              to the callee is possible.  */
>>           if (!p)
>>             break;
>> -         arg = gimple_call_arg (stmt, i);
>> +
>>           if (p == error_mark_node
>>               || arg == error_mark_node
>>               || (!types_compatible_p (DECL_ARG_TYPE (p), TREE_TYPE (arg))
>>                   && !fold_convertible_p (DECL_ARG_TYPE (p), arg)))
>>              return false;
>> +
>> +         p = DECL_CHAIN (p);
>>         }
>>        if (args_count_match && p)
>>         return false;
>>      }
>>    else if (parms)
>>      {
>> -      for (i = 0, p = parms; i < nargs; i++, p = TREE_CHAIN (p))
>> +      for (i = 0, p = parms; i < nargs; i++)
>>         {
>> -         tree arg;
>> +         tree arg = gimple_call_arg (stmt, i);
>> +
>> +         /* Skip bound args inserted by Pointer Bounds Checker.  */
>> +         if (POINTER_BOUNDS_P (arg))
>> +           continue;
>> +
>>           /* If this is a varargs function defer inlining decision
>>              to callee.  */
>>           if (!p)
>>             break;
>> -         arg = gimple_call_arg (stmt, i);
>> +
>>           if (TREE_VALUE (p) == error_mark_node
>>               || arg == error_mark_node
>>               || TREE_CODE (TREE_VALUE (p)) == VOID_TYPE
>>               || (!types_compatible_p (TREE_VALUE (p), TREE_TYPE (arg))
>>                   && !fold_convertible_p (TREE_VALUE (p), arg)))
>>              return false;
>> +
>> +         p = TREE_CHAIN (p);
>>         }
>>      }
>>    else
>> diff --git a/gcc/gimple.c b/gcc/gimple.c
>> index 20f6010..dc85bf8 100644
>> --- a/gcc/gimple.c
>> +++ b/gcc/gimple.c
>> @@ -3048,15 +3048,20 @@ canonicalize_cond_expr_cond (tree t)
>>  gimple
>>  gimple_call_copy_skip_args (gimple stmt, bitmap args_to_skip)
>>  {
>> -  int i;
>> +  int i, bit;
>>    int nargs = gimple_call_num_args (stmt);
>>    vec<tree> vargs;
>>    vargs.create (nargs);
>>    gimple new_stmt;
>>
>> -  for (i = 0; i < nargs; i++)
>> -    if (!bitmap_bit_p (args_to_skip, i))
>> -      vargs.quick_push (gimple_call_arg (stmt, i));
>> +  for (i = 0, bit = 0; i < nargs; i++, bit++)
>> +      if (POINTER_BOUNDS_P (gimple_call_arg (stmt, i)))
>> +       {
>> +         if (!bitmap_bit_p (args_to_skip, --bit))
>> +           vargs.quick_push (gimple_call_arg (stmt, i));
>> +       }
>> +      else if (!bitmap_bit_p (args_to_skip, bit))
>> +         vargs.quick_push (gimple_call_arg (stmt, i));
>
> The new code is completely confusing.  You need to update
> comments with what bits args_to_skip refers to and what happens
> with pointer bounds.  I suppose the bitmap also contains
> bound parameters as they are in calls (but not in fndecls -- I think
> this discrepancy still is a way to desaster).

args_to_skip here does not hold bits for bounds. It's content is equal
for both instrumented and original call.  Will make it explicit in
comments.

>
>>    if (gimple_call_internal_p (stmt))
>>      new_stmt = gimple_build_call_internal_vec (gimple_call_internal_fn (stmt),
>> @@ -3702,6 +3707,9 @@ validate_call (gimple stmt, tree fndecl)
>>        if (!targs)
>>         return true;
>>        tree arg = gimple_call_arg (stmt, i);
>> +      /* Skip bounds.  */
>> +      if (flag_check_pointer_bounds && POINTER_BOUNDS_P (arg))
>> +       continue;
>
> Why check flag_check_pointer_bounds here but not elsewhere?

No reason actually. I'll remove flag check here.

>
>>        if (INTEGRAL_TYPE_P (TREE_TYPE (arg))
>>           && INTEGRAL_TYPE_P (TREE_VALUE (targs)))
>>         ;