1 /* Convert language-specific tree expression to rtl instructions,
3 Copyright (C) 1988-2018 Free Software Foundation, Inc.
5 This file is part of GCC.
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)
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.
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/>. */
24 #include "coretypes.h"
27 /* Expand C++-specific constants. Currently, this means PTRMEM_CST. */
30 cplus_expand_constant (tree cst)
32 switch (TREE_CODE (cst))
36 tree type = TREE_TYPE (cst);
39 /* Find the member. */
40 member = PTRMEM_CST_MEMBER (cst);
42 /* We can't lower this until the class is complete. */
43 if (!COMPLETE_TYPE_P (DECL_CONTEXT (member)))
46 if (TREE_CODE (member) == FIELD_DECL)
48 /* Find the offset for the field. */
49 cst = byte_position (member);
50 while (!same_type_p (DECL_CONTEXT (member),
51 TYPE_PTRMEM_CLASS_TYPE (type)))
53 /* The MEMBER must have been nestled within an
54 anonymous aggregate contained in TYPE. Find the
55 anonymous aggregate. */
56 member = lookup_anon_field (TYPE_PTRMEM_CLASS_TYPE (type),
57 DECL_CONTEXT (member));
58 cst = size_binop (PLUS_EXPR, cst, byte_position (member));
60 cst = fold (build_nop (type, cst));
67 expand_ptrmemfunc_cst (cst, &delta, &pfn);
68 cst = build_ptrmemfunc1 (type, delta, pfn);
76 unsigned HOST_WIDE_INT idx;
77 FOR_EACH_VEC_SAFE_ELT (CONSTRUCTOR_ELTS (cst), idx, elt)
78 elt->value = cplus_expand_constant (elt->value);
82 /* There's nothing to do. */
89 /* We've seen an actual use of EXPR. Possibly replace an outer variable
90 reference inside with its constant value or a lambda capture. */
93 mark_use (tree expr, bool rvalue_p, bool read_p,
94 location_t loc /* = UNKNOWN_LOCATION */,
95 bool reject_builtin /* = true */)
97 #define RECUR(t) mark_use ((t), rvalue_p, read_p, loc, reject_builtin)
99 if (expr == NULL_TREE || expr == error_mark_node)
102 if (reject_builtin && reject_gcc_builtin (expr, loc))
103 return error_mark_node;
106 mark_exp_read (expr);
109 bool recurse_op[3] = { false, false, false };
110 switch (TREE_CODE (expr))
114 if (rvalue_p && is_normal_capture_proxy (expr))
116 /* Look through capture by copy. */
117 tree cap = DECL_CAPTURED_VARIABLE (expr);
118 if (TREE_CODE (TREE_TYPE (cap)) == TREE_CODE (TREE_TYPE (expr))
119 && decl_constant_var_p (cap))
121 tree val = RECUR (cap);
122 if (!is_capture_proxy (val))
124 tree l = current_lambda_expr ();
125 LAMBDA_EXPR_CAPTURE_OPTIMIZED (l) = true;
130 if (outer_automatic_var_p (expr)
131 && decl_constant_var_p (expr))
135 tree t = maybe_constant_value (expr);
136 if (TREE_CONSTANT (t))
142 temp_override<location_t> l (input_location);
143 if (loc != UNKNOWN_LOCATION)
144 input_location = loc;
145 expr = process_outer_var_ref (expr, tf_warning_or_error, true);
146 if (!(TREE_TYPE (oexpr)
147 && TREE_CODE (TREE_TYPE (oexpr)) == REFERENCE_TYPE))
148 expr = convert_from_reference (expr);
152 case NON_DEPENDENT_EXPR:
153 recurse_op[0] = true;
156 recurse_op[1] = true;
159 recurse_op[2] = true;
160 if (TREE_OPERAND (expr, 1))
161 recurse_op[1] = true;
164 if (REFERENCE_REF_P (expr))
166 /* Try to look through the reference. */
167 tree ref = TREE_OPERAND (expr, 0);
168 if (rvalue_p && is_normal_capture_proxy (ref))
170 /* Look through capture by reference. */
171 tree cap = DECL_CAPTURED_VARIABLE (ref);
172 if (TREE_CODE (TREE_TYPE (cap)) != REFERENCE_TYPE
173 && decl_constant_var_p (cap))
175 tree val = RECUR (cap);
176 if (!is_capture_proxy (val))
178 tree l = current_lambda_expr ();
179 LAMBDA_EXPR_CAPTURE_OPTIMIZED (l) = true;
184 tree r = mark_rvalue_use (ref, loc, reject_builtin);
186 expr = convert_from_reference (r);
191 case VIEW_CONVERT_EXPR:
192 if (location_wrapper_p (expr))
193 loc = EXPR_LOCATION (expr);
194 recurse_op[0] = true;
201 for (int i = 0; i < 3; ++i)
204 tree op = TREE_OPERAND (expr, i);
206 if (op == error_mark_node)
207 return error_mark_node;
208 TREE_OPERAND (expr, i) = op;
215 /* Called whenever the expression EXPR is used in an rvalue context.
216 When REJECT_BUILTIN is true the expression is checked to make sure
217 it doesn't make it possible to obtain the address of a GCC built-in
218 function with no library fallback (or any of its bits, such as in
219 a conversion to bool). */
222 mark_rvalue_use (tree e,
223 location_t loc /* = UNKNOWN_LOCATION */,
224 bool reject_builtin /* = true */)
226 return mark_use (e, true, true, loc, reject_builtin);
229 /* Called whenever an expression is used in an lvalue context. */
232 mark_lvalue_use (tree expr)
234 return mark_use (expr, false, true, input_location, false);
237 /* As above, but don't consider this use a read. */
240 mark_lvalue_use_nonread (tree expr)
242 return mark_use (expr, false, false, input_location, false);
245 /* Called when expr appears as a discarded-value expression. */
248 mark_discarded_use (tree expr)
250 /* The lvalue-to-rvalue conversion (7.1) is applied if and only if the
251 expression is a glvalue of volatile-qualified type and it is one of the
253 * ( expression ), where expression is one of these expressions,
254 * id-expression (8.1.4),
255 * subscripting (8.2.1),
256 * class member access (8.2.5),
257 * indirection (8.3.1),
258 * pointer-to-member operation (8.5),
259 * conditional expression (8.16) where both the second and the third
260 operands are one of these expressions, or
261 * comma expression (8.19) where the right operand is one of these
263 if (expr == NULL_TREE)
266 switch (TREE_CODE (expr))
269 TREE_OPERAND (expr, 2) = mark_discarded_use (TREE_OPERAND (expr, 2));
272 TREE_OPERAND (expr, 1) = mark_discarded_use (TREE_OPERAND (expr, 1));
287 /* Like mark_rvalue_use, but don't reject built-ins. */
288 return mark_use (expr, true, true, input_location, false);
291 /* Called whenever an expression is used in a type use context. */
294 mark_type_use (tree expr)
296 mark_exp_read (expr);
300 /* Mark EXP as read, not just set, for set but not used -Wunused
304 mark_exp_read (tree exp)
309 switch (TREE_CODE (exp))
312 if (DECL_DECOMPOSITION_P (exp))
313 mark_exp_read (DECL_DECOMP_BASE (exp));
316 DECL_READ_P (exp) = 1;
327 case NON_DEPENDENT_EXPR:
328 case VIEW_CONVERT_EXPR:
329 mark_exp_read (TREE_OPERAND (exp, 0));
332 mark_exp_read (TREE_OPERAND (exp, 1));
335 if (TREE_OPERAND (exp, 1))
336 mark_exp_read (TREE_OPERAND (exp, 1));
337 if (TREE_OPERAND (exp, 2))
338 mark_exp_read (TREE_OPERAND (exp, 2));
345 /* Fold X for consideration by one of the warning functions when checking
346 whether an expression has a constant value. */
349 fold_for_warn (tree x)
351 /* C++ implementation. */
353 /* It's not generally safe to fully fold inside of a template, so
354 call fold_non_dependent_expr instead. */
355 if (processing_template_decl)
356 return fold_non_dependent_expr (x);
358 return c_fully_fold (x, /*for_init*/false, /*maybe_constp*/NULL);