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7675e968 | 1 | /* -Wnonnull-compare warning support. |
fbd26352 | 2 | Copyright (C) 2016-2019 Free Software Foundation, Inc. |
7675e968 | 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 (stmt); | |
57 | if (gimple_code (stmt) == GIMPLE_COND) | |
58 | switch (gimple_cond_code (stmt)) | |
59 | { | |
60 | case EQ_EXPR: | |
61 | case NE_EXPR: | |
62 | if (gimple_cond_lhs (stmt) == d) | |
63 | op = gimple_cond_rhs (stmt); | |
64 | break; | |
65 | default: | |
66 | break; | |
67 | } | |
68 | else if (is_gimple_assign (stmt)) | |
69 | switch (gimple_assign_rhs_code (stmt)) | |
70 | { | |
71 | case EQ_EXPR: | |
72 | case NE_EXPR: | |
73 | if (gimple_assign_rhs1 (stmt) == d) | |
74 | op = gimple_assign_rhs2 (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 (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)) | |
fc3527e3 | 99 | ? integer_zerop (op) : integer_minus_onep (op)) |
100 | && !gimple_no_warning_p (stmt)) | |
7675e968 | 101 | warning_at (loc, OPT_Wnonnull_compare, |
62c34df8 | 102 | "%<nonnull%> argument %qD compared to NULL", arg); |
7675e968 | 103 | } |
104 | } | |
105 | ||
106 | namespace { | |
107 | ||
108 | const pass_data pass_data_warn_nonnull_compare = | |
109 | { | |
110 | GIMPLE_PASS, /* type */ | |
111 | "*nonnullcmp", /* name */ | |
112 | OPTGROUP_NONE, /* optinfo_flags */ | |
113 | TV_NONE, /* tv_id */ | |
114 | PROP_ssa, /* properties_required */ | |
115 | 0, /* properties_provided */ | |
116 | 0, /* properties_destroyed */ | |
117 | 0, /* todo_flags_start */ | |
118 | 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 | virtual bool gate (function *) { return warn_nonnull_compare; } | |
130 | ||
131 | virtual unsigned int execute (function *); | |
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, 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 | } |