On Thu, Oct 15, 2020 at 11:50:28PM +0200, Jan Hubicka wrote:
> Hi,
> this patch implements the discussed change to fnspecs to make it
> possible to specify parameters that are read and written. In addition
> to original plan I ended up adding 'b' for functions that are barriers
> (since those alias even with local refs) and 'o','O' for parameters that
> are written only (output parameters) so there is diffence betwen strcat
> and memcpy, for example.
>
> Bootstrapped/regtested x86_64-linux, OK?
>
> Honza
>
> 2020-10-15 Jan Hubicka <hubi...@ucw.cz>
>
> * attr-fnspec.h: Update toplevel comment.
> (attr_fnspec::attr_fnspec): New constructor.
> (attr_fnspec::arg_read_p,
> attr_fnspec::arg_written_p,
> attr_fnspec::arg_access_size_given_by_arg_p,
> attr_fnspec::arg_single_access_p
> attr_fnspec::loads_known_p
> attr_fnspec::stores_known_p,
> attr_fnspec::clobbers_errno_p): New member functions.
> (gimple_call_fnspec): Declare.
> (builtin_fnspec): Declare.
> * builtins.c: Include attr-fnspec.h
> (builtin_fnspec): New function.
> * builtins.def (BUILT_IN_MEMCPY): Do not specify RET1 fnspec.
> (BUILT_IN_MEMMOVE): Do not specify RET1 fnspec.
> (BUILT_IN_MEMSET): Do not specify RET1 fnspec.
> (BUILT_IN_STRCAT): Do not specify RET1 fnspec.
> (BUILT_IN_STRCPY): Do not specify RET1 fnspec.
> (BUILT_IN_STRNCAT): Do not specify RET1 fnspec.
> (BUILT_IN_STRNCPY): Do not specify RET1 fnspec.
> (BUILT_IN_MEMCPY_CHK): Do not specify RET1 fnspec.
> (BUILT_IN_MEMMOVE_CHK): Do not specify RET1 fnspec.
> (BUILT_IN_MEMSET_CHK): Do not specify RET1 fnspec.
> (BUILT_IN_STRCAT_CHK): Do not specify RET1 fnspec.
> (BUILT_IN_STRCPY_CHK): Do not specify RET1 fnspec.
> (BUILT_IN_STRNCAT_CHK): Do not specify RET1 fnspec.
> (BUILT_IN_STRNCPY_CHK): Do not specify RET1 fnspec.
> * gimple.c (gimple_call_fnspec): Return attr_fnspec.
> (gimple_call_arg_flags): Update.
> (gimple_call_return_flags): Update.
> * tree-ssa-alias.c (check_fnspec): New function.
> (ref_maybe_used_by_call_p_1): Use fnspec for builtin handling.
> (call_may_clobber_ref_p_1): Likewise.
> (attr_fnspec::verify): Update verifier.
> * calls.c (decl_fnspec): New function.
> (decl_return_flags): Use it.
> diff --git a/gcc/attr-fnspec.h b/gcc/attr-fnspec.h
> index d38b84a969e..e524798c4ca 100644
> --- a/gcc/attr-fnspec.h
> +++ b/gcc/attr-fnspec.h
> @@ -27,11 +27,19 @@
> '.' specifies that nothing is known.
> character 1 specifies additional function properties
> ' ' specifies that nothing is known
> + 'p' or 'P' specifies that function is pure except for described side
> + effects.
> + 'c' or 'C' specifies that function is const except for described side
> + effects.
> + 'b' specifies that functions is a memory barrier.
> + The uppercase letter in addition specifies that function clobbers errno.
>
> character 2+2i specifies properties of argument number i as follows:
> 'x' or 'X' specifies that parameter is unused.
> 'r' or 'R' specifies that the memory pointed to by the parameter is only
> read and does not escape
> + 'o' or 'O' specifies that the memory pointed to by the parameter is only
> + written and does not escape
> 'w' or 'W' specifies that the memory pointed to by the parameter does
> not
> escape
> '.' specifies that nothing is known.
> @@ -42,6 +50,10 @@
> character 3+2i specifies additional properties of argument number i
> as follows:
> ' ' nothing is known
> + 't' the size of value written/read corresponds to the size of
> + of the pointed-to type of the argument type
> + '1'...'9' the size of value written/read is given by the specified
> + argument
> */
>
> #ifndef ATTR_FNSPEC_H
> @@ -72,6 +84,12 @@ public:
> if (flag_checking)
> verify ();
> }
> + attr_fnspec (const char *str)
> + : str (str), len (strlen (str))
> + {
> + if (flag_checking)
> + verify ();
> + }
> attr_fnspec (const_tree identifier)
> : str (TREE_STRING_POINTER (identifier)),
> len (TREE_STRING_LENGTH (identifier))
> @@ -79,6 +97,17 @@ public:
> if (flag_checking)
> verify ();
> }
> + attr_fnspec ()
> + : str (NULL), len (0)
> + {
> + }
> +
> + /* Return true if fn spec is known. */
> + bool
> + known_p ()
> + {
> + return len;
> + }
>
> /* Return true if arg I is specified. */
> bool
> @@ -94,7 +123,7 @@ public:
> {
> unsigned int idx = arg_idx (i);
> gcc_checking_assert (arg_specified_p (i));
> - return str[idx] == 'R' || str[idx] == 'W';
> + return str[idx] == 'R' || str[idx] == 'O' || str[idx] == 'W';
> }
>
> /* True if argument is used. */
> @@ -115,6 +144,56 @@ public:
> return str[idx] == 'r' || str[idx] == 'R';
> }
>
> + /* True if memory reached by the argument is read.
> + Valid only if all loads are known. */
> + bool
> + arg_read_p (unsigned int i)
> + {
> + unsigned int idx = arg_idx (i);
> + gcc_checking_assert (arg_specified_p (i));
> + gcc_checking_assert (loads_known_p ());
> + return str[idx] == 'r' || str[idx] == 'R'
> + || str[idx] == 'w' || str[idx] == 'W';
> + }
> +
> + /* True if memory reached by the argument is read.
> + Valid only if all loads are known. */
> + bool
> + arg_written_p (unsigned int i)
> + {
> + unsigned int idx = arg_idx (i);
> + gcc_checking_assert (arg_specified_p (i));
> + gcc_checking_assert (stores_known_p ());
> + return str[idx] == 'w' || str[idx] == 'W'
> + || str[idx] == 'o' || str[idx] == 'O';
> + }
> +
> + /* Return true if load of memory pointed to by argument I is specified
> + by another argument. In this case set ARG. */
> + bool
> + arg_access_size_given_by_arg_p (unsigned int i, unsigned int *arg)
> + {
> + unsigned int idx = arg_idx (i);
> + gcc_checking_assert (arg_specified_p (i));
> + if (str[idx + 1] >= '1' && str[idx + 1] <= '9')
> + {
> + *arg = str[idx + 1] - '1';
> + return true;
> + }
> + else
> + return false;
> + }
> +
> + /* Return true if the pointed-to type of the argument correspond to the
> + size of the memory acccess. */
> + bool
> + arg_single_access_p (unsigned int i)
> + {
> + unsigned int idx = arg_idx (i);
> + gcc_checking_assert (arg_specified_p (i));
> + return str[idx + 1] == 't';
> + }
> +
> /* True if the argument does not escape. */
> bool
> arg_noescape_p (unsigned int i)
> @@ -122,7 +201,8 @@ public:
> unsigned int idx = arg_idx (i);
> gcc_checking_assert (arg_specified_p (i));
> return str[idx] == 'w' || str[idx] == 'W'
> - || str[idx] == 'R' || str[idx] == 'r';
> + || str[idx] == 'r' || str[idx] == 'R'
> + || str[idx] == 'o' || str[idx] == 'o';
Did you mean
|| str[idx] == 'o' || str[idx] == 'O';
here?
Marek
