1 | /* -Wnonnull-compare warning support. |
2 | Copyright (C) 2016-2024 Free Software Foundation, Inc. |
3 | Contributed by Jakub Jelinek <jakub@redhat.com> |
4 | |
5 | This file is part of GCC. |
6 | |
7 | GCC is free software; you can redistribute it and/or modify |
8 | it under the terms of the GNU General Public License as published by |
9 | the Free Software Foundation; either version 3, or (at your option) |
10 | any later version. |
11 | |
12 | GCC is distributed in the hope that it will be useful, |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
15 | GNU General Public License for more details. |
16 | |
17 | You should have received a copy of the GNU General Public License |
18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ |
20 | |
21 | #include "config.h" |
22 | #include "system.h" |
23 | #include "coretypes.h" |
24 | #include "backend.h" |
25 | #include "tree.h" |
26 | #include "gimple.h" |
27 | #include "tree-pass.h" |
28 | #include "ssa.h" |
29 | #include "diagnostic-core.h" |
30 | #include "tree-dfa.h" |
31 | |
32 | /* Warn about comparison of nonnull_arg_p argument initial values |
33 | with NULL. */ |
34 | |
35 | static void |
36 | do_warn_nonnull_compare (function *fun, tree arg) |
37 | { |
38 | if (!POINTER_TYPE_P (TREE_TYPE (arg)) |
39 | && TREE_CODE (TREE_TYPE (arg)) != OFFSET_TYPE) |
40 | return; |
41 | |
42 | if (!nonnull_arg_p (arg)) |
43 | return; |
44 | |
45 | tree d = ssa_default_def (fun, arg); |
46 | if (d == NULL_TREE) |
47 | return; |
48 | |
49 | use_operand_p use_p; |
50 | imm_use_iterator iter; |
51 | |
52 | FOR_EACH_IMM_USE_FAST (use_p, iter, d) |
53 | { |
54 | gimple *stmt = USE_STMT (use_p); |
55 | tree op = NULL_TREE; |
56 | location_t loc = gimple_location (g: stmt); |
57 | if (gimple_code (g: stmt) == GIMPLE_COND) |
58 | switch (gimple_cond_code (gs: stmt)) |
59 | { |
60 | case EQ_EXPR: |
61 | case NE_EXPR: |
62 | if (gimple_cond_lhs (gs: stmt) == d) |
63 | op = gimple_cond_rhs (gs: stmt); |
64 | break; |
65 | default: |
66 | break; |
67 | } |
68 | else if (is_gimple_assign (gs: stmt)) |
69 | switch (gimple_assign_rhs_code (gs: stmt)) |
70 | { |
71 | case EQ_EXPR: |
72 | case NE_EXPR: |
73 | if (gimple_assign_rhs1 (gs: stmt) == d) |
74 | op = gimple_assign_rhs2 (gs: stmt); |
75 | break; |
76 | case COND_EXPR: |
77 | switch (TREE_CODE (gimple_assign_rhs1 (stmt))) |
78 | { |
79 | case EQ_EXPR: |
80 | case NE_EXPR: |
81 | op = gimple_assign_rhs1 (gs: stmt); |
82 | if (TREE_OPERAND (op, 0) != d) |
83 | { |
84 | op = NULL_TREE; |
85 | break; |
86 | } |
87 | loc = EXPR_LOC_OR_LOC (op, loc); |
88 | op = TREE_OPERAND (op, 1); |
89 | break; |
90 | default: |
91 | break; |
92 | } |
93 | break; |
94 | default: |
95 | break; |
96 | } |
97 | if (op |
98 | && (POINTER_TYPE_P (TREE_TYPE (arg)) |
99 | ? integer_zerop (op) : integer_minus_onep (op)) |
100 | && !warning_suppressed_p (stmt, OPT_Wnonnull_compare)) |
101 | warning_at (loc, OPT_Wnonnull_compare, |
102 | "%<nonnull%> argument %qD compared to NULL" , arg); |
103 | } |
104 | } |
105 | |
106 | namespace { |
107 | |
108 | const pass_data pass_data_warn_nonnull_compare = |
109 | { |
110 | .type: GIMPLE_PASS, /* type */ |
111 | .name: "*nonnullcmp" , /* name */ |
112 | .optinfo_flags: OPTGROUP_NONE, /* optinfo_flags */ |
113 | .tv_id: TV_NONE, /* tv_id */ |
114 | PROP_ssa, /* properties_required */ |
115 | .properties_provided: 0, /* properties_provided */ |
116 | .properties_destroyed: 0, /* properties_destroyed */ |
117 | .todo_flags_start: 0, /* todo_flags_start */ |
118 | .todo_flags_finish: 0, /* todo_flags_finish */ |
119 | }; |
120 | |
121 | class pass_warn_nonnull_compare : public gimple_opt_pass |
122 | { |
123 | public: |
124 | pass_warn_nonnull_compare (gcc::context *ctxt) |
125 | : gimple_opt_pass (pass_data_warn_nonnull_compare, ctxt) |
126 | {} |
127 | |
128 | /* opt_pass methods: */ |
129 | bool gate (function *) final override { return warn_nonnull_compare; } |
130 | |
131 | unsigned int execute (function *) final override; |
132 | |
133 | }; // class pass_warn_nonnull_compare |
134 | |
135 | unsigned int |
136 | pass_warn_nonnull_compare::execute (function *fun) |
137 | { |
138 | if (fun->static_chain_decl) |
139 | do_warn_nonnull_compare (fun, arg: fun->static_chain_decl); |
140 | |
141 | for (tree arg = DECL_ARGUMENTS (cfun->decl); arg; arg = DECL_CHAIN (arg)) |
142 | do_warn_nonnull_compare (fun, arg); |
143 | return 0; |
144 | } |
145 | |
146 | } // anon namespace |
147 | |
148 | gimple_opt_pass * |
149 | make_pass_warn_nonnull_compare (gcc::context *ctxt) |
150 | { |
151 | return new pass_warn_nonnull_compare (ctxt); |
152 | } |
153 | |