xref: /netbsd-src/external/gpl3/gcc.old/dist/gcc/c-family/c-semantics.c (revision 946379e7b37692fc43f68eb0d1c10daa0a7f3b6c)
1 /* This file contains subroutine used by the C front-end to construct GENERIC.
2    Copyright (C) 2000-2013 Free Software Foundation, Inc.
3    Written by Benjamin Chelf (chelf@codesourcery.com).
4 
5 This file is part of GCC.
6 
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
11 
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15 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 "tm.h"
25 #include "tree.h"
26 #include "function.h"
27 #include "splay-tree.h"
28 #include "c-common.h"
29 #include "flags.h"
30 #include "tree-iterator.h"
31 
32 /* Create an empty statement tree rooted at T.  */
33 
34 tree
35 push_stmt_list (void)
36 {
37   tree t;
38   t = alloc_stmt_list ();
39   vec_safe_push (stmt_list_stack, t);
40   return t;
41 }
42 
43 /* Finish the statement tree rooted at T.  */
44 
45 tree
46 pop_stmt_list (tree t)
47 {
48   tree u = NULL_TREE;
49 
50   /* Pop statement lists until we reach the target level.  The extra
51      nestings will be due to outstanding cleanups.  */
52   while (1)
53     {
54       u = stmt_list_stack->pop ();
55       if (!stmt_list_stack->is_empty ())
56 	{
57 	  tree x = stmt_list_stack->last ();
58 	  STATEMENT_LIST_HAS_LABEL (x) |= STATEMENT_LIST_HAS_LABEL (u);
59 	}
60       if (t == u)
61 	break;
62     }
63 
64   gcc_assert (u != NULL_TREE);
65 
66   /* If the statement list is completely empty, just return it.  This is
67      just as good small as build_empty_stmt, with the advantage that
68      statement lists are merged when they appended to one another.  So
69      using the STATEMENT_LIST avoids pathological buildup of EMPTY_STMT_P
70      statements.  */
71   if (TREE_SIDE_EFFECTS (t))
72     {
73       tree_stmt_iterator i = tsi_start (t);
74 
75       /* If the statement list contained exactly one statement, then
76 	 extract it immediately.  */
77       if (tsi_one_before_end_p (i))
78 	{
79 	  u = tsi_stmt (i);
80 	  tsi_delink (&i);
81 	  free_stmt_list (t);
82 	  t = u;
83 	}
84     }
85 
86   return t;
87 }
88 
89 /* Build a generic statement based on the given type of node and
90    arguments. Similar to `build_nt', except that we set
91    EXPR_LOCATION to LOC. */
92 /* ??? This should be obsolete with the lineno_stmt productions
93    in the grammar.  */
94 
95 tree
96 build_stmt (location_t loc, enum tree_code code, ...)
97 {
98   tree ret;
99   int length, i;
100   va_list p;
101   bool side_effects;
102 
103   /* This function cannot be used to construct variably-sized nodes.  */
104   gcc_assert (TREE_CODE_CLASS (code) != tcc_vl_exp);
105 
106   va_start (p, code);
107 
108   ret = make_node (code);
109   TREE_TYPE (ret) = void_type_node;
110   length = TREE_CODE_LENGTH (code);
111   SET_EXPR_LOCATION (ret, loc);
112 
113   /* TREE_SIDE_EFFECTS will already be set for statements with
114      implicit side effects.  Here we make sure it is set for other
115      expressions by checking whether the parameters have side
116      effects.  */
117 
118   side_effects = false;
119   for (i = 0; i < length; i++)
120     {
121       tree t = va_arg (p, tree);
122       if (t && !TYPE_P (t))
123 	side_effects |= TREE_SIDE_EFFECTS (t);
124       TREE_OPERAND (ret, i) = t;
125     }
126 
127   TREE_SIDE_EFFECTS (ret) |= side_effects;
128 
129   va_end (p);
130   return ret;
131 }
132 
133 /* Build a REALPART_EXPR or IMAGPART_EXPR, according to CODE, from ARG.  */
134 
135 tree
136 build_real_imag_expr (location_t location, enum tree_code code, tree arg)
137 {
138   tree ret;
139   tree arg_type = TREE_TYPE (arg);
140 
141   gcc_assert (code == REALPART_EXPR || code == IMAGPART_EXPR);
142 
143   if (TREE_CODE (arg_type) == COMPLEX_TYPE)
144     {
145       ret = build1 (code, TREE_TYPE (TREE_TYPE (arg)), arg);
146       SET_EXPR_LOCATION (ret, location);
147     }
148   else if (INTEGRAL_TYPE_P (arg_type) || SCALAR_FLOAT_TYPE_P (arg_type))
149     {
150       ret = (code == REALPART_EXPR
151 	     ? arg
152 	     : omit_one_operand_loc (location, arg_type,
153 				     integer_zero_node, arg));
154     }
155   else
156     {
157       error_at (location, "wrong type argument to %s",
158 		code == REALPART_EXPR ? "__real" : "__imag");
159       ret = error_mark_node;
160     }
161 
162   return ret;
163 }
164