import of gcc-2.8
[official-gcc.git] / gcc / cp / class.h
blob12e45f78415c0f7610067fb0474afd2cffa2934e
1 /* Variables and structures for overloading rules.
2 Copyright (C) 1993 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /* The following structure is used when comparing various alternatives
22 for overloading. The unsigned quantity `strikes.i' is used
23 for fast comparison of two possibilities. This number is an
24 aggregate of four constituents:
26 EVIL: if this is non-zero, then the candidate should not be considered
27 ELLIPSIS: if this is non-zero, then some actual argument has been matched
28 against an ellipsis
29 USER: if this is non-zero, then a user-defined type conversion is needed
30 B_OR_D: if this is non-zero, then use a base pointer instead of the
31 type of the pointer we started with.
32 EASY: if this is non-zero, then we have a builtin conversion
33 (such as int to long, int to float, etc) to do.
35 If two candidates require user-defined type conversions, and the
36 type conversions are not identical, then an ambiguity error
37 is reported.
39 If two candidates agree on user-defined type conversions,
40 and one uses pointers of strictly higher type (derived where
41 another uses base), then that alternative is silently chosen.
43 Note that this technique really only works for 255 arguments. Perhaps
44 this is not enough. */
46 /* These macros and harshness_code are used by the NEW METHOD. */
47 #define EVIL_CODE (1<<7)
48 #define CONST_CODE (1<<6)
49 #define ELLIPSIS_CODE (1<<5)
50 #define USER_CODE (1<<4)
51 #define STD_CODE (1<<3)
52 #define PROMO_CODE (1<<2)
53 #define QUAL_CODE (1<<1)
54 #define TRIVIAL_CODE (1<<0)
56 struct harshness_code
58 /* What kind of conversion is involved. */
59 unsigned short code;
61 /* The inheritance distance. */
62 short distance;
64 /* For a PROMO_CODE, Any special penalties involved in integral conversions.
65 This exists because $4.1 of the ARM states that something like
66 `short unsigned int' should promote to `int', not `unsigned int'.
67 If, for example, it tries to match two fns, f(int) and f(unsigned),
68 f(int) should be a better match than f(unsigned) by this rule. Without
69 this extra metric, they both only appear as "integral promotions", which
70 will lead to an ambiguity.
71 For a TRIVIAL_CODE, This is also used by build_overload_call_real and
72 convert_harshness to keep track of other information we need. */
73 unsigned short int_penalty;
76 struct candidate
78 struct harshness_code h; /* Used for single-argument conversions. */
80 int h_len; /* The length of the harshness vector. */
82 tree function; /* A FUNCTION_DECL */
83 tree basetypes; /* The path to function. */
84 tree arg; /* first parm to function. */
86 /* Indexed by argument number, encodes evil, user, d_to_b, and easy
87 strikes for that argument. At end of array, we store the index+1
88 of where we started using default parameters, or 0 if there are
89 none. */
90 struct harshness_code *harshness;
92 union
94 tree field; /* If no evil strikes, the FUNCTION_DECL of
95 the function (if a member function). */
96 int bad_arg; /* the index of the first bad argument:
97 0 if no bad arguments
98 > 0 is first bad argument
99 -1 if extra actual arguments
100 -2 if too few actual arguments.
101 -3 if const/non const method mismatch.
102 -4 if type unification failed.
103 -5 if contravariance violation. */
104 } u;
106 int rank_for_overload PROTO ((struct candidate *, struct candidate *));
108 /* Variables shared between class.c and call.c. */
110 extern int n_vtables;
111 extern int n_vtable_entries;
112 extern int n_vtable_searches;
113 extern int n_vtable_elems;
114 extern int n_convert_harshness;
115 extern int n_compute_conversion_costs;
116 extern int n_build_method_call;
117 extern int n_inner_fields_searched;