1 /* Control and data flow functions for trees.
2 Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
23 #include "coretypes.h"
26 #include "tree-inline.h"
28 #include "langhooks.h"
36 /* Called to move the SAVE_EXPRs for parameter declarations in a
37 nested function into the nested function. DATA is really the
38 nested FUNCTION_DECL. */
41 set_save_expr_context (tree *tp,
45 if (TREE_CODE (*tp) == SAVE_EXPR && !SAVE_EXPR_CONTEXT (*tp))
46 SAVE_EXPR_CONTEXT (*tp) = (tree) data;
47 /* Do not walk back into the SAVE_EXPR_CONTEXT; that will cause
49 else if (DECL_P (*tp))
55 /* Clear out the DECL_RTL for the non-static local variables in BLOCK and
56 its sub-blocks. DATA is the decl of the function being processed. */
59 clear_decl_rtl (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED, void *data)
61 bool nonstatic_p, local_p;
64 switch (TREE_CODE (t))
67 nonstatic_p = !TREE_STATIC (t) && !DECL_EXTERNAL (t);
68 local_p = DECL_CONTEXT (t) == data;
74 local_p = DECL_CONTEXT (t) == data;
78 nonstatic_p = local_p = true;
82 nonstatic_p = local_p = false;
86 if (nonstatic_p && local_p)
87 SET_DECL_RTL (t, NULL);
92 /* For functions-as-trees languages, this performs all optimization and
93 compilation for FNDECL. */
96 tree_rest_of_compilation (tree fndecl, bool nested_p)
98 timevar_push (TV_EXPAND);
100 if (flag_unit_at_a_time && !cgraph_global_info_ready)
103 /* Initialize the RTL code for the function. */
104 current_function_decl = fndecl;
105 input_location = DECL_SOURCE_LOCATION (fndecl);
106 init_function_start (fndecl);
108 /* This function is being processed in whole-function mode. */
109 cfun->x_whole_function_mode_p = 1;
111 /* Even though we're inside a function body, we still don't want to
112 call expand_expr to calculate the size of a variable-sized array.
113 We haven't necessarily assigned RTL to all variables yet, so it's
114 not safe to try to expand expressions involving them. */
115 immediate_size_expand = 0;
116 cfun->x_dont_save_pending_sizes_p = 1;
118 /* If the function has a variably modified type, there may be
119 SAVE_EXPRs in the parameter types. Their context must be set to
120 refer to this function; they cannot be expanded in the containing
122 if (decl_function_context (fndecl)
123 && variably_modified_type_p (TREE_TYPE (fndecl)))
124 walk_tree (&TREE_TYPE (fndecl), set_save_expr_context, fndecl,
127 /* Set up parameters and prepare for return, for the function. */
128 expand_function_start (fndecl, 0);
130 /* Allow language dialects to perform special processing. */
131 (*lang_hooks.rtl_expand.start) ();
133 /* If this function is `main', emit a call to `__main'
134 to run global initializers, etc. */
135 if (DECL_NAME (fndecl)
136 && MAIN_NAME_P (DECL_NAME (fndecl))
137 && DECL_FILE_SCOPE_P (fndecl))
138 expand_main_function ();
140 /* Generate the RTL for this function. */
141 (*lang_hooks.rtl_expand.stmt) (DECL_SAVED_TREE (fndecl));
143 /* We hard-wired immediate_size_expand to zero above.
144 expand_function_end will decrement this variable. So, we set the
145 variable to one here, so that after the decrement it will remain
147 immediate_size_expand = 1;
149 /* Allow language dialects to perform special processing. */
150 (*lang_hooks.rtl_expand.end) ();
152 /* Generate rtl for function exit. */
153 expand_function_end ();
155 /* If this is a nested function, protect the local variables in the stack
156 above us from being collected while we're compiling this function. */
160 /* There's no need to defer outputting this function any more; we
161 know we want to output it. */
162 DECL_DEFER_OUTPUT (fndecl) = 0;
164 /* Run the optimizers and output the assembler code for this function. */
165 rest_of_compilation (fndecl);
167 /* Undo the GC context switch. */
171 /* If requested, warn about function definitions where the function will
172 return a value (usually of some struct or union type) which itself will
173 take up a lot of stack space. */
174 if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))
176 tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));
178 if (ret_type && TYPE_SIZE_UNIT (ret_type)
179 && TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST
180 && 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),
183 const location_t *locus = &DECL_SOURCE_LOCATION (fndecl);
184 unsigned int size_as_int
185 = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));
187 if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)
188 warning ("%Hsize of return value of '%D' is %u bytes",
189 locus, fndecl, size_as_int);
191 warning ("%Hsize of return value of '%D' is larger than %wd bytes",
192 locus, fndecl, larger_than_size);
196 /* ??? Looks like some of this could be combined. */
198 /* If possible, obliterate the body of the function so that it can
199 be garbage collected. */
200 if (dump_enabled_p (TDI_all))
201 /* Keep the body; we're going to dump it. */
203 else if (DECL_INLINE (fndecl) && flag_inline_trees)
204 /* We might need the body of this function so that we can expand
205 it inline somewhere else. */
208 /* We don't need the body; blow it away. */
209 DECL_SAVED_TREE (fndecl) = NULL;
211 /* Since we don't need the RTL for this function anymore, stop pointing to
212 it. That's especially important for LABEL_DECLs, since you can reach all
213 the instructions in the function from the CODE_LABEL stored in the
214 DECL_RTL for the LABEL_DECL. Walk the BLOCK-tree, clearing DECL_RTL for
215 LABEL_DECLs and non-static local variables. Note that we must check the
216 context of the variables, otherwise processing a nested function can kill
217 the rtl of a variable from an outer function. */
218 walk_tree_without_duplicates (&DECL_SAVED_TREE (fndecl),
222 if (DECL_SAVED_INSNS (fndecl) == 0 && !nested_p && !flag_inline_trees)
224 /* Stop pointing to the local nodes about to be freed.
225 But DECL_INITIAL must remain nonzero so we know this
226 was an actual function definition.
227 For a nested function, this is done in c_pop_function_context.
228 If rest_of_compilation set this to 0, leave it 0. */
229 if (DECL_INITIAL (fndecl) != 0)
230 DECL_INITIAL (fndecl) = error_mark_node;
232 DECL_ARGUMENTS (fndecl) = 0;
235 timevar_pop (TV_EXPAND);