1 | /* Tree lowering to gimple for middle end use only. |
2 | This converts the GENERIC functions-as-trees tree representation into |
3 | the GIMPLE form. |
4 | Copyright (C) 2013-2023 Free Software Foundation, Inc. |
5 | Major work done by Sebastian Pop <s.pop@laposte.net>, |
6 | Diego Novillo <dnovillo@redhat.com> and Jason Merrill <jason@redhat.com>. |
7 | |
8 | This file is part of GCC. |
9 | |
10 | GCC is free software; you can redistribute it and/or modify it under |
11 | the terms of the GNU General Public License as published by the Free |
12 | Software Foundation; either version 3, or (at your option) any later |
13 | version. |
14 | |
15 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
16 | WARRANTY; without even the implied warranty of MERCHANTABILITY or |
17 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
18 | for more details. |
19 | |
20 | You should have received a copy of the GNU General Public License |
21 | along with GCC; see the file COPYING3. If not see |
22 | <http://www.gnu.org/licenses/>. */ |
23 | |
24 | #include "config.h" |
25 | #include "system.h" |
26 | #include "coretypes.h" |
27 | #include "backend.h" |
28 | #include "tree.h" |
29 | #include "gimple.h" |
30 | #include "ssa.h" |
31 | #include "stmt.h" |
32 | #include "stor-layout.h" |
33 | #include "tree-eh.h" |
34 | #include "gimple-iterator.h" |
35 | #include "gimplify.h" |
36 | #include "gimplify-me.h" |
37 | |
38 | |
39 | /* Expand EXPR to list of gimple statements STMTS. GIMPLE_TEST_F specifies |
40 | the predicate that will hold for the result. If VAR is not NULL, make the |
41 | base variable of the final destination be VAR if suitable. */ |
42 | |
43 | tree |
44 | force_gimple_operand_1 (tree expr, gimple_seq *stmts, |
45 | gimple_predicate gimple_test_f, tree var) |
46 | { |
47 | enum gimplify_status ret; |
48 | location_t saved_location; |
49 | |
50 | *stmts = NULL; |
51 | |
52 | /* gimple_test_f might be more strict than is_gimple_val, make |
53 | sure we pass both. Just checking gimple_test_f doesn't work |
54 | because most gimple predicates do not work recursively. */ |
55 | if (is_gimple_val (expr) |
56 | && (*gimple_test_f) (expr)) |
57 | return expr; |
58 | |
59 | push_gimplify_context (in_ssa: gimple_in_ssa_p (cfun), rhs_cond_ok: true); |
60 | saved_location = input_location; |
61 | input_location = UNKNOWN_LOCATION; |
62 | |
63 | if (var) |
64 | { |
65 | if (gimple_in_ssa_p (cfun) && is_gimple_reg (var)) |
66 | var = make_ssa_name (var); |
67 | expr = build2 (MODIFY_EXPR, TREE_TYPE (var), var, expr); |
68 | } |
69 | |
70 | if (TREE_CODE (expr) != MODIFY_EXPR |
71 | && TREE_TYPE (expr) == void_type_node) |
72 | { |
73 | gimplify_and_add (expr, stmts); |
74 | expr = NULL_TREE; |
75 | } |
76 | else |
77 | { |
78 | ret = gimplify_expr (&expr, stmts, NULL, gimple_test_f, fb_rvalue); |
79 | gcc_assert (ret != GS_ERROR); |
80 | } |
81 | |
82 | input_location = saved_location; |
83 | pop_gimplify_context (NULL); |
84 | |
85 | return expr; |
86 | } |
87 | |
88 | /* Expand EXPR to list of gimple statements STMTS. If SIMPLE is true, |
89 | force the result to be either ssa_name or an invariant, otherwise |
90 | just force it to be a rhs expression. If VAR is not NULL, make the |
91 | base variable of the final destination be VAR if suitable. */ |
92 | |
93 | tree |
94 | force_gimple_operand (tree expr, gimple_seq *stmts, bool simple, tree var) |
95 | { |
96 | return force_gimple_operand_1 (expr, stmts, |
97 | gimple_test_f: simple ? is_gimple_val : is_gimple_reg_rhs, |
98 | var); |
99 | } |
100 | |
101 | /* Invoke force_gimple_operand_1 for EXPR with parameters GIMPLE_TEST_F |
102 | and VAR. If some statements are produced, emits them at GSI. |
103 | If BEFORE is true. the statements are appended before GSI, otherwise |
104 | they are appended after it. M specifies the way GSI moves after |
105 | insertion (GSI_SAME_STMT or GSI_CONTINUE_LINKING are the usual values). */ |
106 | |
107 | tree |
108 | force_gimple_operand_gsi_1 (gimple_stmt_iterator *gsi, tree expr, |
109 | gimple_predicate gimple_test_f, |
110 | tree var, bool before, |
111 | enum gsi_iterator_update m) |
112 | { |
113 | gimple_seq stmts; |
114 | |
115 | expr = force_gimple_operand_1 (expr, stmts: &stmts, gimple_test_f, var); |
116 | |
117 | if (!gimple_seq_empty_p (s: stmts)) |
118 | { |
119 | if (before) |
120 | gsi_insert_seq_before (gsi, stmts, m); |
121 | else |
122 | gsi_insert_seq_after (gsi, stmts, m); |
123 | } |
124 | |
125 | return expr; |
126 | } |
127 | |
128 | /* Invoke force_gimple_operand_1 for EXPR with parameter VAR. |
129 | If SIMPLE is true, force the result to be either ssa_name or an invariant, |
130 | otherwise just force it to be a rhs expression. If some statements are |
131 | produced, emits them at GSI. If BEFORE is true, the statements are |
132 | appended before GSI, otherwise they are appended after it. M specifies |
133 | the way GSI moves after insertion (GSI_SAME_STMT or GSI_CONTINUE_LINKING |
134 | are the usual values). */ |
135 | |
136 | tree |
137 | force_gimple_operand_gsi (gimple_stmt_iterator *gsi, tree expr, |
138 | bool simple_p, tree var, bool before, |
139 | enum gsi_iterator_update m) |
140 | { |
141 | return force_gimple_operand_gsi_1 (gsi, expr, |
142 | gimple_test_f: simple_p |
143 | ? is_gimple_val : is_gimple_reg_rhs, |
144 | var, before, m); |
145 | } |
146 | |
147 | /* Some transformations like inlining may invalidate the GIMPLE form |
148 | for operands. This function traverses all the operands in STMT and |
149 | gimplifies anything that is not a valid gimple operand. Any new |
150 | GIMPLE statements are inserted before *GSI_P. */ |
151 | |
152 | void |
153 | gimple_regimplify_operands (gimple *stmt, gimple_stmt_iterator *gsi_p) |
154 | { |
155 | size_t i, num_ops; |
156 | tree lhs; |
157 | gimple_seq pre = NULL; |
158 | gimple *post_stmt = NULL; |
159 | |
160 | push_gimplify_context (in_ssa: gimple_in_ssa_p (cfun)); |
161 | |
162 | switch (gimple_code (g: stmt)) |
163 | { |
164 | case GIMPLE_COND: |
165 | { |
166 | gcond *cond_stmt = as_a <gcond *> (p: stmt); |
167 | gimplify_expr (gimple_cond_lhs_ptr (gs: cond_stmt), &pre, NULL, |
168 | is_gimple_val, fb_rvalue); |
169 | gimplify_expr (gimple_cond_rhs_ptr (gs: cond_stmt), &pre, NULL, |
170 | is_gimple_val, fb_rvalue); |
171 | } |
172 | break; |
173 | case GIMPLE_SWITCH: |
174 | gimplify_expr (gimple_switch_index_ptr (gs: as_a <gswitch *> (p: stmt)), |
175 | &pre, NULL, is_gimple_val, fb_rvalue); |
176 | break; |
177 | case GIMPLE_OMP_ATOMIC_LOAD: |
178 | gimplify_expr (gimple_omp_atomic_load_rhs_ptr ( |
179 | load_stmt: as_a <gomp_atomic_load *> (p: stmt)), |
180 | &pre, NULL, is_gimple_val, fb_rvalue); |
181 | break; |
182 | case GIMPLE_ASM: |
183 | { |
184 | gasm *asm_stmt = as_a <gasm *> (p: stmt); |
185 | size_t i, noutputs = gimple_asm_noutputs (asm_stmt); |
186 | const char *constraint, **oconstraints; |
187 | bool allows_mem, allows_reg, is_inout; |
188 | |
189 | oconstraints |
190 | = (const char **) alloca ((noutputs) * sizeof (const char *)); |
191 | for (i = 0; i < noutputs; i++) |
192 | { |
193 | tree op = gimple_asm_output_op (asm_stmt, index: i); |
194 | constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (op))); |
195 | oconstraints[i] = constraint; |
196 | parse_output_constraint (&constraint, i, 0, 0, &allows_mem, |
197 | &allows_reg, &is_inout); |
198 | gimplify_expr (&TREE_VALUE (op), &pre, NULL, |
199 | is_inout ? is_gimple_min_lval : is_gimple_lvalue, |
200 | fb_lvalue | fb_mayfail); |
201 | } |
202 | for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++) |
203 | { |
204 | tree op = gimple_asm_input_op (asm_stmt, index: i); |
205 | constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (op))); |
206 | parse_input_constraint (&constraint, 0, 0, noutputs, 0, |
207 | oconstraints, &allows_mem, &allows_reg); |
208 | if (TREE_ADDRESSABLE (TREE_TYPE (TREE_VALUE (op))) && allows_mem) |
209 | allows_reg = 0; |
210 | if (!allows_reg && allows_mem) |
211 | gimplify_expr (&TREE_VALUE (op), &pre, NULL, |
212 | is_gimple_lvalue, fb_lvalue | fb_mayfail); |
213 | else |
214 | gimplify_expr (&TREE_VALUE (op), &pre, NULL, |
215 | is_gimple_asm_val, fb_rvalue); |
216 | } |
217 | } |
218 | break; |
219 | default: |
220 | /* NOTE: We start gimplifying operands from last to first to |
221 | make sure that side-effects on the RHS of calls, assignments |
222 | and ASMs are executed before the LHS. The ordering is not |
223 | important for other statements. */ |
224 | num_ops = gimple_num_ops (gs: stmt); |
225 | for (i = num_ops; i > 0; i--) |
226 | { |
227 | tree op = gimple_op (gs: stmt, i: i - 1); |
228 | if (op == NULL_TREE) |
229 | continue; |
230 | if (i == 1 && (is_gimple_call (gs: stmt) || is_gimple_assign (gs: stmt))) |
231 | gimplify_expr (&op, &pre, NULL, is_gimple_lvalue, fb_lvalue); |
232 | else if (i == 2 |
233 | && gimple_assign_single_p (gs: stmt) |
234 | && num_ops == 2) |
235 | gimplify_expr (&op, &pre, NULL, |
236 | rhs_predicate_for (gimple_assign_lhs (gs: stmt)), |
237 | fb_rvalue); |
238 | else if (i == 2 && is_gimple_call (gs: stmt)) |
239 | { |
240 | if (TREE_CODE (op) == FUNCTION_DECL) |
241 | continue; |
242 | gimplify_expr (&op, &pre, NULL, is_gimple_call_addr, fb_rvalue); |
243 | } |
244 | else |
245 | gimplify_expr (&op, &pre, NULL, is_gimple_val, fb_rvalue); |
246 | gimple_set_op (gs: stmt, i: i - 1, op); |
247 | } |
248 | |
249 | lhs = gimple_get_lhs (stmt); |
250 | /* If the LHS changed it in a way that requires a simple RHS, |
251 | create temporary. */ |
252 | if (lhs && !is_gimple_reg (lhs)) |
253 | { |
254 | bool need_temp = false; |
255 | |
256 | if (gimple_assign_single_p (gs: stmt) |
257 | && num_ops == 2) |
258 | gimplify_expr (gimple_assign_rhs1_ptr (gs: stmt), &pre, NULL, |
259 | rhs_predicate_for (gimple_assign_lhs (gs: stmt)), |
260 | fb_rvalue); |
261 | else if (is_gimple_reg (lhs)) |
262 | { |
263 | if (is_gimple_reg_type (TREE_TYPE (lhs))) |
264 | { |
265 | if (is_gimple_call (gs: stmt)) |
266 | { |
267 | i = gimple_call_flags (stmt); |
268 | if ((i & ECF_LOOPING_CONST_OR_PURE) |
269 | || !(i & (ECF_CONST | ECF_PURE))) |
270 | need_temp = true; |
271 | } |
272 | if (stmt_can_throw_internal (cfun, stmt)) |
273 | need_temp = true; |
274 | } |
275 | } |
276 | else |
277 | { |
278 | if (is_gimple_reg_type (TREE_TYPE (lhs))) |
279 | need_temp = true; |
280 | else if (TYPE_MODE (TREE_TYPE (lhs)) != BLKmode) |
281 | { |
282 | if (is_gimple_call (gs: stmt)) |
283 | { |
284 | tree fndecl = gimple_call_fndecl (gs: stmt); |
285 | |
286 | if (!aggregate_value_p (TREE_TYPE (lhs), fndecl) |
287 | && !(fndecl && DECL_RESULT (fndecl) |
288 | && DECL_BY_REFERENCE (DECL_RESULT (fndecl)))) |
289 | need_temp = true; |
290 | } |
291 | else |
292 | need_temp = true; |
293 | } |
294 | } |
295 | if (need_temp) |
296 | { |
297 | tree temp = create_tmp_reg (TREE_TYPE (lhs)); |
298 | if (gimple_in_ssa_p (cfun) |
299 | && is_gimple_reg_type (TREE_TYPE (lhs))) |
300 | temp = make_ssa_name (var: temp); |
301 | gimple_set_lhs (stmt, temp); |
302 | post_stmt = gimple_build_assign (lhs, temp); |
303 | } |
304 | } |
305 | break; |
306 | } |
307 | |
308 | if (!gimple_seq_empty_p (s: pre)) |
309 | gsi_insert_seq_before (gsi_p, pre, GSI_SAME_STMT); |
310 | if (post_stmt) |
311 | gsi_insert_after (gsi_p, post_stmt, GSI_NEW_STMT); |
312 | |
313 | pop_gimplify_context (NULL); |
314 | |
315 | update_stmt (s: stmt); |
316 | } |
317 | |
318 | |
319 | |