1 /* Callgraph based intraprocedural optimizations.
2 Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
3 Contributed by Jan Hubicka
5 This file is part of GCC.
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 2, or (at your option) any later
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
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
22 /* This module implements main driver of compilation process as well as
23 few basic intraprocedural optimizers.
25 The main scope of this file is to act as an interface in between
26 tree based frontends and the backend (and middle end)
28 The front-end is supposed to use following functionality:
30 - cgraph_finalize_function
32 This function is called once front-end has parsed whole body of function
33 and it is certain that the function body nor the declaration will change.
35 (There is one exception needed for implementing GCC extern inline function.)
37 - cgraph_varpool_finalize_variable
39 This function has same behavior as the above but is used for static
42 - cgraph_finalize_compilation_unit
44 This function is called once compilation unit is finalized and it will
47 In the unit-at-a-time the call-graph construction and local function
48 analysis takes place here. Bodies of unreachable functions are released
49 to conserve memory usage.
51 ??? The compilation unit in this point of view should be compilation
52 unit as defined by the language - for instance C frontend allows multiple
53 compilation units to be parsed at once and it should call function each
54 time parsing is done so we save memory.
58 In this unit-at-a-time compilation the intra procedural analysis takes
59 place here. In particular the static functions whose address is never
60 taken are marked as local. Backend can then use this information to
61 modify calling conventions, do better inlining or similar optimizations.
63 - cgraph_assemble_pending_functions
64 - cgraph_varpool_assemble_pending_variables
66 In non-unit-at-a-time mode these functions can be used to force compilation
67 of functions or variables that are known to be needed at given stage
70 - cgraph_mark_needed_node
71 - cgraph_varpool_mark_needed_node
73 When function or variable is referenced by some hidden way (for instance
74 via assembly code and marked by attribute "used"), the call-graph data structure
75 must be updated accordingly by this function.
77 - analyze_expr callback
79 This function is responsible for lowering tree nodes not understood by
80 generic code into understandable ones or alternatively marking
81 callgraph and varpool nodes referenced by the as needed.
83 ??? On the tree-ssa genericizing should take place here and we will avoid
84 need for these hooks (replacing them by genericizing hook)
86 - expand_function callback
88 This function is used to expand function and pass it into RTL back-end.
89 Front-end should not make any assumptions about when this function can be
90 called. In particular cgraph_assemble_pending_functions,
91 cgraph_varpool_assemble_pending_variables, cgraph_finalize_function,
92 cgraph_varpool_finalize_function, cgraph_optimize can cause arbitrarily
93 previously finalized functions to be expanded.
95 We implement two compilation modes.
97 - unit-at-a-time: In this mode analyzing of all functions is deferred
98 to cgraph_finalize_compilation_unit and expansion into cgraph_optimize.
100 In cgraph_finalize_compilation_unit the reachable functions are
101 analyzed. During analysis the call-graph edges from reachable
102 functions are constructed and their destinations are marked as
103 reachable. References to functions and variables are discovered too
104 and variables found to be needed output to the assembly file. Via
105 mark_referenced call in assemble_variable functions referenced by
106 static variables are noticed too.
108 The intra-procedural information is produced and its existence
109 indicated by global_info_ready. Once this flag is set it is impossible
110 to change function from !reachable to reachable and thus
111 assemble_variable no longer call mark_referenced.
113 Finally the call-graph is topologically sorted and all reachable functions
114 that has not been completely inlined or are not external are output.
116 ??? It is possible that reference to function or variable is optimized
117 out. We can not deal with this nicely because topological order is not
118 suitable for it. For tree-ssa we may consider another pass doing
119 optimization and re-discovering reachable functions.
121 ??? Reorganize code so variables are output very last and only if they
122 really has been referenced by produced code, so we catch more cases
123 where reference has been optimized out.
127 All functions are variables are output as early as possible to conserve
128 memory consumption. This may or may not result in less memory used but
129 it is still needed for some legacy code that rely on particular ordering
130 of things output from the compiler.
132 Varpool data structures are not used and variables are output directly.
134 Functions are output early using call of
135 cgraph_assemble_pending_function from cgraph_finalize_function. The
136 decision on whether function is needed is made more conservative so
137 uninlininable static functions are needed too. During the call-graph
138 construction the edge destinations are not marked as reachable and it
139 is completely relied upn assemble_variable to mark them. */
144 #include "coretypes.h"
148 #include "tree-flow.h"
149 #include "tree-inline.h"
150 #include "langhooks.h"
151 #include "pointer-set.h"
158 #include "diagnostic.h"
162 #include "c-common.h"
164 #include "function.h"
165 #include "tree-gimple.h"
166 #include "tree-pass.h"
169 static void cgraph_expand_all_functions (void);
170 static void cgraph_mark_functions_to_output (void);
171 static void cgraph_expand_function (struct cgraph_node
*);
172 static tree
record_reference (tree
*, int *, void *);
173 static void cgraph_analyze_function (struct cgraph_node
*node
);
175 /* Records tree nodes seen in record_reference. Simply using
176 walk_tree_without_duplicates doesn't guarantee each node is visited
177 once because it gets a new htab upon each recursive call from
178 record_reference itself. */
179 static struct pointer_set_t
*visited_nodes
;
181 static FILE *cgraph_dump_file
;
183 /* Determine if function DECL is needed. That is, visible to something
184 either outside this translation unit, something magic in the system
185 configury, or (if not doing unit-at-a-time) to something we havn't
189 decide_is_function_needed (struct cgraph_node
*node
, tree decl
)
192 if (MAIN_NAME_P (DECL_NAME (decl
))
193 && TREE_PUBLIC (decl
))
195 node
->local
.externally_visible
= true;
199 /* If the user told us it is used, then it must be so. */
200 if (node
->local
.externally_visible
201 || lookup_attribute ("used", DECL_ATTRIBUTES (decl
)))
204 /* ??? If the assembler name is set by hand, it is possible to assemble
205 the name later after finalizing the function and the fact is noticed
206 in assemble_name then. This is arguably a bug. */
207 if (DECL_ASSEMBLER_NAME_SET_P (decl
)
208 && TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl
)))
211 /* If we decided it was needed before, but at the time we didn't have
212 the body of the function available, then it's still needed. We have
213 to go back and re-check its dependencies now. */
217 /* Externally visible functions must be output. The exception is
218 COMDAT functions that must be output only when they are needed. */
219 if ((TREE_PUBLIC (decl
) && !flag_whole_program
)
220 && !DECL_COMDAT (decl
) && !DECL_EXTERNAL (decl
))
223 /* Constructors and destructors are reachable from the runtime by
225 if (DECL_STATIC_CONSTRUCTOR (decl
) || DECL_STATIC_DESTRUCTOR (decl
))
228 if (flag_unit_at_a_time
)
231 /* If not doing unit at a time, then we'll only defer this function
232 if its marked for inlining. Otherwise we want to emit it now. */
234 /* "extern inline" functions are never output locally. */
235 if (DECL_EXTERNAL (decl
))
237 /* Nested functions of extern inline function shall not be emit unless
238 we inlined the origin. */
239 for (origin
= decl_function_context (decl
); origin
;
240 origin
= decl_function_context (origin
))
241 if (DECL_EXTERNAL (origin
))
243 /* We want to emit COMDAT functions only when absolutely necessary. */
244 if (DECL_COMDAT (decl
))
246 if (!DECL_INLINE (decl
)
247 || (!node
->local
.disregard_inline_limits
248 /* When declared inline, defer even the uninlinable functions.
249 This allows them to be eliminated when unused. */
250 && !DECL_DECLARED_INLINE_P (decl
)
251 && (!node
->local
.inlinable
|| !cgraph_default_inline_p (node
))))
257 /* Walk the decls we marked as necessary and see if they reference new
258 variables or functions and add them into the worklists. */
260 cgraph_varpool_analyze_pending_decls (void)
262 bool changed
= false;
263 timevar_push (TV_CGRAPH
);
265 while (cgraph_varpool_first_unanalyzed_node
)
267 tree decl
= cgraph_varpool_first_unanalyzed_node
->decl
;
269 cgraph_varpool_first_unanalyzed_node
->analyzed
= true;
271 cgraph_varpool_first_unanalyzed_node
= cgraph_varpool_first_unanalyzed_node
->next_needed
;
273 if (DECL_INITIAL (decl
))
275 visited_nodes
= pointer_set_create ();
276 walk_tree (&DECL_INITIAL (decl
), record_reference
, NULL
, visited_nodes
);
277 pointer_set_destroy (visited_nodes
);
278 visited_nodes
= NULL
;
282 timevar_pop (TV_CGRAPH
);
286 /* Optimization of function bodies might've rendered some variables as
287 unnecessary so we want to avoid these from being compiled.
289 This is done by pruning the queue and keeping only the variables that
290 really appear needed (ie they are either externally visible or referenced
291 by compiled function). Re-doing the reachability analysis on variables
292 brings back the remaining variables referenced by these. */
294 cgraph_varpool_remove_unreferenced_decls (void)
296 struct cgraph_varpool_node
*next
, *node
= cgraph_varpool_nodes_queue
;
298 cgraph_varpool_reset_queue ();
300 if (errorcount
|| sorrycount
)
305 tree decl
= node
->decl
;
306 next
= node
->next_needed
;
310 && ((DECL_ASSEMBLER_NAME_SET_P (decl
)
311 && TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl
)))
312 || node
->force_output
313 || decide_is_variable_needed (node
, decl
)))
314 cgraph_varpool_mark_needed_node (node
);
318 cgraph_varpool_analyze_pending_decls ();
322 /* When not doing unit-at-a-time, output all functions enqueued.
323 Return true when such a functions were found. */
326 cgraph_assemble_pending_functions (void)
330 if (flag_unit_at_a_time
)
333 while (cgraph_nodes_queue
)
335 struct cgraph_node
*n
= cgraph_nodes_queue
;
337 cgraph_nodes_queue
= cgraph_nodes_queue
->next_needed
;
338 n
->next_needed
= NULL
;
339 if (!n
->global
.inlined_to
341 && !DECL_EXTERNAL (n
->decl
))
343 cgraph_expand_function (n
);
350 /* As an GCC extension we allow redefinition of the function. The
351 semantics when both copies of bodies differ is not well defined.
352 We replace the old body with new body so in unit at a time mode
353 we always use new body, while in normal mode we may end up with
354 old body inlined into some functions and new body expanded and
357 ??? It may make more sense to use one body for inlining and other
358 body for expanding the function but this is difficult to do. */
361 cgraph_reset_node (struct cgraph_node
*node
)
363 /* If node->output is set, then this is a unit-at-a-time compilation
364 and we have already begun whole-unit analysis. This is *not*
365 testing for whether we've already emitted the function. That
366 case can be sort-of legitimately seen with real function
367 redefinition errors. I would argue that the front end should
368 never present us with such a case, but don't enforce that for now. */
369 gcc_assert (!node
->output
);
371 /* Reset our data structures so we can analyze the function again. */
372 memset (&node
->local
, 0, sizeof (node
->local
));
373 memset (&node
->global
, 0, sizeof (node
->global
));
374 memset (&node
->rtl
, 0, sizeof (node
->rtl
));
375 node
->analyzed
= false;
376 node
->local
.redefined_extern_inline
= true;
377 node
->local
.finalized
= false;
379 if (!flag_unit_at_a_time
)
381 struct cgraph_node
*n
;
383 for (n
= cgraph_nodes
; n
; n
= n
->next
)
384 if (n
->global
.inlined_to
== node
)
385 cgraph_remove_node (n
);
388 cgraph_node_remove_callees (node
);
390 /* We may need to re-queue the node for assembling in case
391 we already proceeded it and ignored as not needed. */
392 if (node
->reachable
&& !flag_unit_at_a_time
)
394 struct cgraph_node
*n
;
396 for (n
= cgraph_nodes_queue
; n
; n
= n
->next_needed
)
404 /* DECL has been parsed. Take it, queue it, compile it at the whim of the
405 logic in effect. If NESTED is true, then our caller cannot stand to have
406 the garbage collector run at the moment. We would need to either create
407 a new GC context, or just not compile right now. */
410 cgraph_finalize_function (tree decl
, bool nested
)
412 struct cgraph_node
*node
= cgraph_node (decl
);
414 if (node
->local
.finalized
)
415 cgraph_reset_node (node
);
417 notice_global_symbol (decl
);
419 node
->local
.finalized
= true;
420 node
->lowered
= DECL_STRUCT_FUNCTION (decl
)->cfg
!= NULL
;
422 lower_nested_functions (decl
);
423 gcc_assert (!node
->nested
);
425 /* If not unit at a time, then we need to create the call graph
426 now, so that called functions can be queued and emitted now. */
427 if (!flag_unit_at_a_time
)
429 cgraph_analyze_function (node
);
430 cgraph_decide_inlining_incrementally (node
);
433 if (decide_is_function_needed (node
, decl
))
434 cgraph_mark_needed_node (node
);
436 /* Since we reclaim unreachable nodes at the end of every language
437 level unit, we need to be conservative about possible entry points
439 if ((TREE_PUBLIC (decl
) && !DECL_COMDAT (decl
) && !DECL_EXTERNAL (decl
)))
440 cgraph_mark_reachable_node (node
);
442 /* If not unit at a time, go ahead and emit everything we've found
443 to be reachable at this time. */
446 if (!cgraph_assemble_pending_functions ())
450 /* If we've not yet emitted decl, tell the debug info about it. */
451 if (!TREE_ASM_WRITTEN (decl
))
452 (*debug_hooks
->deferred_inline_function
) (decl
);
454 /* Possibly warn about unused parameters. */
455 if (warn_unused_parameter
)
456 do_warn_unused_parameter (decl
);
460 cgraph_lower_function (struct cgraph_node
*node
)
464 tree_lowering_passes (node
->decl
);
465 node
->lowered
= true;
468 /* Walk tree and record all calls. Called via walk_tree. */
470 record_reference (tree
*tp
, int *walk_subtrees
, void *data
)
474 switch (TREE_CODE (t
))
477 /* ??? Really, we should mark this decl as *potentially* referenced
478 by this function and re-examine whether the decl is actually used
479 after rtl has been generated. */
480 if (TREE_STATIC (t
) || DECL_EXTERNAL (t
))
482 cgraph_varpool_mark_needed_node (cgraph_varpool_node (t
));
483 if (lang_hooks
.callgraph
.analyze_expr
)
484 return lang_hooks
.callgraph
.analyze_expr (tp
, walk_subtrees
,
491 if (flag_unit_at_a_time
)
493 /* Record dereferences to the functions. This makes the
494 functions reachable unconditionally. */
495 tree decl
= TREE_OPERAND (*tp
, 0);
496 if (TREE_CODE (decl
) == FUNCTION_DECL
)
497 cgraph_mark_needed_node (cgraph_node (decl
));
502 /* Save some cycles by not walking types and declaration as we
503 won't find anything useful there anyway. */
504 if (IS_TYPE_OR_DECL_P (*tp
))
510 if ((unsigned int) TREE_CODE (t
) >= LAST_AND_UNUSED_TREE_CODE
)
511 return lang_hooks
.callgraph
.analyze_expr (tp
, walk_subtrees
, data
);
518 /* Create cgraph edges for function calls inside BODY from NODE. */
521 cgraph_create_edges (struct cgraph_node
*node
, tree body
)
525 struct function
*this_cfun
= DECL_STRUCT_FUNCTION (body
);
526 block_stmt_iterator bsi
;
528 visited_nodes
= pointer_set_create ();
530 /* Reach the trees by walking over the CFG, and note the
531 enclosing basic-blocks in the call edges. */
532 FOR_EACH_BB_FN (bb
, this_cfun
)
533 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
535 tree stmt
= bsi_stmt (bsi
);
536 tree call
= get_call_expr_in (stmt
);
539 if (call
&& (decl
= get_callee_fndecl (call
)))
541 cgraph_create_edge (node
, cgraph_node (decl
), stmt
,
544 walk_tree (&TREE_OPERAND (call
, 1),
545 record_reference
, node
, visited_nodes
);
546 if (TREE_CODE (stmt
) == MODIFY_EXPR
)
547 walk_tree (&TREE_OPERAND (stmt
, 0),
548 record_reference
, node
, visited_nodes
);
551 walk_tree (bsi_stmt_ptr (bsi
), record_reference
, node
, visited_nodes
);
554 /* Look for initializers of constant variables and private statics. */
555 for (step
= DECL_STRUCT_FUNCTION (body
)->unexpanded_var_list
;
557 step
= TREE_CHAIN (step
))
559 tree decl
= TREE_VALUE (step
);
560 if (TREE_CODE (decl
) == VAR_DECL
561 && (TREE_STATIC (decl
) && !DECL_EXTERNAL (decl
))
562 && flag_unit_at_a_time
)
563 cgraph_varpool_finalize_decl (decl
);
564 else if (TREE_CODE (decl
) == VAR_DECL
&& DECL_INITIAL (decl
))
565 walk_tree (&DECL_INITIAL (decl
), record_reference
, node
, visited_nodes
);
568 pointer_set_destroy (visited_nodes
);
569 visited_nodes
= NULL
;
573 /* Verify cgraph nodes of given cgraph node. */
575 verify_cgraph_node (struct cgraph_node
*node
)
577 struct cgraph_edge
*e
;
578 struct cgraph_node
*main_clone
;
579 struct function
*this_cfun
= DECL_STRUCT_FUNCTION (node
->decl
);
580 basic_block this_block
;
581 block_stmt_iterator bsi
;
582 bool error_found
= false;
584 timevar_push (TV_CGRAPH_VERIFY
);
585 for (e
= node
->callees
; e
; e
= e
->next_callee
)
588 error ("Aux field set for edge %s->%s",
589 cgraph_node_name (e
->caller
), cgraph_node_name (e
->callee
));
592 for (e
= node
->callers
; e
; e
= e
->next_caller
)
594 if (!e
->inline_failed
)
596 if (node
->global
.inlined_to
597 != (e
->caller
->global
.inlined_to
598 ? e
->caller
->global
.inlined_to
: e
->caller
))
600 error ("Inlined_to pointer is wrong");
603 if (node
->callers
->next_caller
)
605 error ("Multiple inline callers");
610 if (node
->global
.inlined_to
)
612 error ("Inlined_to pointer set for noninline callers");
616 if (!node
->callers
&& node
->global
.inlined_to
)
618 error ("Inlined_to pointer is set but no predecesors found");
621 if (node
->global
.inlined_to
== node
)
623 error ("Inlined_to pointer refers to itself");
627 for (main_clone
= cgraph_node (node
->decl
); main_clone
;
628 main_clone
= main_clone
->next_clone
)
629 if (main_clone
== node
)
633 error ("Node not found in DECL_ASSEMBLER_NAME hash");
638 && DECL_SAVED_TREE (node
->decl
) && !TREE_ASM_WRITTEN (node
->decl
)
639 && (!DECL_EXTERNAL (node
->decl
) || node
->global
.inlined_to
))
643 /* The nodes we're interested in are never shared, so walk
644 the tree ignoring duplicates. */
645 visited_nodes
= pointer_set_create ();
646 /* Reach the trees by walking over the CFG, and note the
647 enclosing basic-blocks in the call edges. */
648 FOR_EACH_BB_FN (this_block
, this_cfun
)
649 for (bsi
= bsi_start (this_block
); !bsi_end_p (bsi
); bsi_next (&bsi
))
651 tree stmt
= bsi_stmt (bsi
);
652 tree call
= get_call_expr_in (stmt
);
654 if (call
&& (decl
= get_callee_fndecl (call
)))
656 struct cgraph_edge
*e
= cgraph_edge (node
, stmt
);
661 error ("Shared call_stmt:");
662 debug_generic_stmt (stmt
);
665 if (e
->callee
->decl
!= cgraph_node (decl
)->decl
)
667 error ("Edge points to wrong declaration:");
668 debug_tree (e
->callee
->decl
);
669 fprintf (stderr
," Instead of:");
676 error ("Missing callgraph edge for call stmt:");
677 debug_generic_stmt (stmt
);
682 pointer_set_destroy (visited_nodes
);
683 visited_nodes
= NULL
;
686 /* No CFG available?! */
689 for (e
= node
->callees
; e
; e
= e
->next_callee
)
693 error ("Edge %s->%s has no corresponding call_stmt",
694 cgraph_node_name (e
->caller
),
695 cgraph_node_name (e
->callee
));
696 debug_generic_stmt (e
->call_stmt
);
704 dump_cgraph_node (stderr
, node
);
705 internal_error ("verify_cgraph_node failed.");
707 timevar_pop (TV_CGRAPH_VERIFY
);
710 /* Verify whole cgraph structure. */
714 struct cgraph_node
*node
;
716 if (sorrycount
|| errorcount
)
719 for (node
= cgraph_nodes
; node
; node
= node
->next
)
720 verify_cgraph_node (node
);
724 /* Output all variables enqueued to be assembled. */
726 cgraph_varpool_assemble_pending_decls (void)
728 bool changed
= false;
730 if (errorcount
|| sorrycount
)
733 /* EH might mark decls as needed during expansion. This should be safe since
734 we don't create references to new function, but it should not be used
736 cgraph_varpool_analyze_pending_decls ();
738 while (cgraph_varpool_nodes_queue
)
740 tree decl
= cgraph_varpool_nodes_queue
->decl
;
741 struct cgraph_varpool_node
*node
= cgraph_varpool_nodes_queue
;
743 cgraph_varpool_nodes_queue
= cgraph_varpool_nodes_queue
->next_needed
;
744 if (!TREE_ASM_WRITTEN (decl
) && !node
->alias
&& !DECL_EXTERNAL (decl
))
746 assemble_variable (decl
, 0, 1, 0);
747 /* Local static variables are never seen by check_global_declarations
748 so we need to output debug info by hand. */
749 if (decl_function_context (decl
) && errorcount
== 0 && sorrycount
== 0)
751 timevar_push (TV_SYMOUT
);
752 (*debug_hooks
->global_decl
) (decl
);
753 timevar_pop (TV_SYMOUT
);
757 node
->next_needed
= NULL
;
762 /* Analyze the function scheduled to be output. */
764 cgraph_analyze_function (struct cgraph_node
*node
)
766 tree decl
= node
->decl
;
767 struct cgraph_edge
*e
;
769 current_function_decl
= decl
;
770 push_cfun (DECL_STRUCT_FUNCTION (decl
));
771 cgraph_lower_function (node
);
773 /* First kill forward declaration so reverse inlining works properly. */
774 cgraph_create_edges (node
, decl
);
776 node
->local
.inlinable
= tree_inlinable_function_p (decl
);
777 node
->local
.self_insns
= estimate_num_insns (decl
);
778 if (node
->local
.inlinable
)
779 node
->local
.disregard_inline_limits
780 = lang_hooks
.tree_inlining
.disregard_inline_limits (decl
);
781 for (e
= node
->callers
; e
; e
= e
->next_caller
)
783 if (node
->local
.redefined_extern_inline
)
784 e
->inline_failed
= N_("redefined extern inline functions are not "
785 "considered for inlining");
786 else if (!node
->local
.inlinable
)
787 e
->inline_failed
= N_("function not inlinable");
789 e
->inline_failed
= N_("function not considered for inlining");
791 if (flag_really_no_inline
&& !node
->local
.disregard_inline_limits
)
792 node
->local
.inlinable
= 0;
793 /* Inlining characteristics are maintained by the cgraph_mark_inline. */
794 node
->global
.insns
= node
->local
.self_insns
;
796 node
->analyzed
= true;
798 current_function_decl
= NULL
;
801 /* Analyze the whole compilation unit once it is parsed completely. */
804 cgraph_finalize_compilation_unit (void)
806 struct cgraph_node
*node
;
807 /* Keep track of already processed nodes when called multiple times for
808 intermodule optimization. */
809 static struct cgraph_node
*first_analyzed
;
813 if (!flag_unit_at_a_time
)
815 cgraph_assemble_pending_functions ();
821 fprintf (stderr
, "\nAnalyzing compilation unit");
825 timevar_push (TV_CGRAPH
);
826 cgraph_varpool_analyze_pending_decls ();
827 if (cgraph_dump_file
)
829 fprintf (cgraph_dump_file
, "Initial entry points:");
830 for (node
= cgraph_nodes
; node
!= first_analyzed
; node
= node
->next
)
831 if (node
->needed
&& DECL_SAVED_TREE (node
->decl
))
832 fprintf (cgraph_dump_file
, " %s", cgraph_node_name (node
));
833 fprintf (cgraph_dump_file
, "\n");
836 /* Propagate reachability flag and lower representation of all reachable
837 functions. In the future, lowering will introduce new functions and
838 new entry points on the way (by template instantiation and virtual
839 method table generation for instance). */
840 while (cgraph_nodes_queue
)
842 struct cgraph_edge
*edge
;
843 tree decl
= cgraph_nodes_queue
->decl
;
845 node
= cgraph_nodes_queue
;
846 cgraph_nodes_queue
= cgraph_nodes_queue
->next_needed
;
847 node
->next_needed
= NULL
;
849 /* ??? It is possible to create extern inline function and later using
850 weak alias attribute to kill its body. See
851 gcc.c-torture/compile/20011119-1.c */
852 if (!DECL_SAVED_TREE (decl
))
854 cgraph_reset_node (node
);
858 gcc_assert (!node
->analyzed
&& node
->reachable
);
859 gcc_assert (DECL_SAVED_TREE (decl
));
861 cgraph_analyze_function (node
);
863 for (edge
= node
->callees
; edge
; edge
= edge
->next_callee
)
864 if (!edge
->callee
->reachable
)
865 cgraph_mark_reachable_node (edge
->callee
);
867 cgraph_varpool_analyze_pending_decls ();
870 /* Collect entry points to the unit. */
872 if (cgraph_dump_file
)
874 fprintf (cgraph_dump_file
, "Unit entry points:");
875 for (node
= cgraph_nodes
; node
!= first_analyzed
; node
= node
->next
)
876 if (node
->needed
&& DECL_SAVED_TREE (node
->decl
))
877 fprintf (cgraph_dump_file
, " %s", cgraph_node_name (node
));
878 fprintf (cgraph_dump_file
, "\n\nInitial ");
879 dump_cgraph (cgraph_dump_file
);
882 if (cgraph_dump_file
)
883 fprintf (cgraph_dump_file
, "\nReclaiming functions:");
885 for (node
= cgraph_nodes
; node
!= first_analyzed
; node
= node
->next
)
887 tree decl
= node
->decl
;
889 if (node
->local
.finalized
&& !DECL_SAVED_TREE (decl
))
890 cgraph_reset_node (node
);
892 if (!node
->reachable
&& DECL_SAVED_TREE (decl
))
894 if (cgraph_dump_file
)
895 fprintf (cgraph_dump_file
, " %s", cgraph_node_name (node
));
896 cgraph_remove_node (node
);
900 node
->next_needed
= NULL
;
901 gcc_assert (!node
->local
.finalized
|| DECL_SAVED_TREE (decl
));
902 gcc_assert (node
->analyzed
== node
->local
.finalized
);
904 if (cgraph_dump_file
)
906 fprintf (cgraph_dump_file
, "\n\nReclaimed ");
907 dump_cgraph (cgraph_dump_file
);
909 first_analyzed
= cgraph_nodes
;
911 timevar_pop (TV_CGRAPH
);
913 /* Figure out what functions we want to assemble. */
916 cgraph_mark_functions_to_output (void)
918 struct cgraph_node
*node
;
920 for (node
= cgraph_nodes
; node
; node
= node
->next
)
922 tree decl
= node
->decl
;
923 struct cgraph_edge
*e
;
925 gcc_assert (!node
->output
);
927 for (e
= node
->callers
; e
; e
= e
->next_caller
)
928 if (e
->inline_failed
)
931 /* We need to output all local functions that are used and not
932 always inlined, as well as those that are reachable from
933 outside the current compilation unit. */
934 if (DECL_SAVED_TREE (decl
)
935 && !node
->global
.inlined_to
937 || (e
&& node
->reachable
))
938 && !TREE_ASM_WRITTEN (decl
)
939 && !DECL_EXTERNAL (decl
))
943 /* We should've reclaimed all functions that are not needed. */
944 #ifdef ENABLE_CHECKING
945 if (!node
->global
.inlined_to
&& DECL_SAVED_TREE (decl
)
946 && !DECL_EXTERNAL (decl
))
948 dump_cgraph_node (stderr
, node
);
949 internal_error ("failed to reclaim unneeded function");
952 gcc_assert (node
->global
.inlined_to
|| !DECL_SAVED_TREE (decl
)
953 || DECL_EXTERNAL (decl
));
960 /* Expand function specified by NODE. */
963 cgraph_expand_function (struct cgraph_node
*node
)
965 tree decl
= node
->decl
;
967 /* We ought to not compile any inline clones. */
968 gcc_assert (!node
->global
.inlined_to
);
970 if (flag_unit_at_a_time
)
971 announce_function (decl
);
973 cgraph_lower_function (node
);
975 /* Generate RTL for the body of DECL. */
976 lang_hooks
.callgraph
.expand_function (decl
);
978 /* Make sure that BE didn't give up on compiling. */
979 /* ??? Can happen with nested function of extern inline. */
980 gcc_assert (TREE_ASM_WRITTEN (node
->decl
));
982 current_function_decl
= NULL
;
983 if (!cgraph_preserve_function_body_p (node
->decl
))
985 DECL_SAVED_TREE (node
->decl
) = NULL
;
986 DECL_STRUCT_FUNCTION (node
->decl
) = NULL
;
987 DECL_INITIAL (node
->decl
) = error_mark_node
;
988 /* Eliminate all call edges. This is important so the call_expr no longer
989 points to the dead function body. */
990 cgraph_node_remove_callees (node
);
993 cgraph_function_flags_ready
= true;
996 /* Return true when CALLER_DECL should be inlined into CALLEE_DECL. */
999 cgraph_inline_p (struct cgraph_edge
*e
, const char **reason
)
1001 *reason
= e
->inline_failed
;
1002 return !e
->inline_failed
;
1007 /* Expand all functions that must be output.
1009 Attempt to topologically sort the nodes so function is output when
1010 all called functions are already assembled to allow data to be
1011 propagated across the callgraph. Use a stack to get smaller distance
1012 between a function and its callees (later we may choose to use a more
1013 sophisticated algorithm for function reordering; we will likely want
1014 to use subsections to make the output functions appear in top-down
1018 cgraph_expand_all_functions (void)
1020 struct cgraph_node
*node
;
1021 struct cgraph_node
**order
=
1022 xcalloc (cgraph_n_nodes
, sizeof (struct cgraph_node
*));
1023 int order_pos
= 0, new_order_pos
= 0;
1026 order_pos
= cgraph_postorder (order
);
1027 gcc_assert (order_pos
== cgraph_n_nodes
);
1029 /* Garbage collector may remove inline clones we eliminate during
1030 optimization. So we must be sure to not reference them. */
1031 for (i
= 0; i
< order_pos
; i
++)
1032 if (order
[i
]->output
)
1033 order
[new_order_pos
++] = order
[i
];
1035 for (i
= new_order_pos
- 1; i
>= 0; i
--)
1040 gcc_assert (node
->reachable
);
1042 cgraph_expand_function (node
);
1048 /* Mark visibility of all functions.
1050 A local function is one whose calls can occur only in the current
1051 compilation unit and all its calls are explicit, so we can change
1052 its calling convention. We simply mark all static functions whose
1053 address is not taken as local.
1055 We also change the TREE_PUBLIC flag of all declarations that are public
1056 in language point of view but we want to overwrite this default
1057 via visibilities for the backend point of view. */
1060 cgraph_function_and_variable_visibility (void)
1062 struct cgraph_node
*node
;
1063 struct cgraph_varpool_node
*vnode
;
1065 for (node
= cgraph_nodes
; node
; node
= node
->next
)
1068 && (DECL_COMDAT (node
->decl
)
1069 || (TREE_PUBLIC (node
->decl
) && !DECL_EXTERNAL (node
->decl
))))
1070 node
->local
.externally_visible
= true;
1071 if (!node
->local
.externally_visible
&& node
->analyzed
1072 && !DECL_EXTERNAL (node
->decl
))
1074 gcc_assert (flag_whole_program
|| !TREE_PUBLIC (node
->decl
));
1075 TREE_PUBLIC (node
->decl
) = 0;
1077 node
->local
.local
= (!node
->needed
1079 && !DECL_EXTERNAL (node
->decl
)
1080 && !node
->local
.externally_visible
);
1082 for (vnode
= cgraph_varpool_nodes_queue
; vnode
; vnode
= vnode
->next_needed
)
1085 && (DECL_COMDAT (vnode
->decl
) || TREE_PUBLIC (vnode
->decl
)))
1086 vnode
->externally_visible
= 1;
1087 if (!vnode
->externally_visible
)
1089 gcc_assert (flag_whole_program
|| !TREE_PUBLIC (vnode
->decl
));
1090 TREE_PUBLIC (vnode
->decl
) = 0;
1092 gcc_assert (TREE_STATIC (vnode
->decl
));
1095 /* Because we have to be conservative on the boundaries of source
1096 level units, it is possible that we marked some functions in
1097 reachable just because they might be used later via external
1098 linkage, but after making them local they are really unreachable
1100 cgraph_remove_unreachable_nodes (true, cgraph_dump_file
);
1102 if (cgraph_dump_file
)
1104 fprintf (cgraph_dump_file
, "\nMarking local functions:");
1105 for (node
= cgraph_nodes
; node
; node
= node
->next
)
1106 if (node
->local
.local
)
1107 fprintf (cgraph_dump_file
, " %s", cgraph_node_name (node
));
1108 fprintf (cgraph_dump_file
, "\n\n");
1109 fprintf (cgraph_dump_file
, "\nMarking externally visible functions:");
1110 for (node
= cgraph_nodes
; node
; node
= node
->next
)
1111 if (node
->local
.externally_visible
)
1112 fprintf (cgraph_dump_file
, " %s", cgraph_node_name (node
));
1113 fprintf (cgraph_dump_file
, "\n\n");
1115 cgraph_function_flags_ready
= true;
1118 /* Return true when function body of DECL still needs to be kept around
1119 for later re-use. */
1121 cgraph_preserve_function_body_p (tree decl
)
1123 struct cgraph_node
*node
;
1124 /* Keep the body; we're going to dump it. */
1125 if (dump_enabled_p (TDI_tree_all
))
1127 if (!cgraph_global_info_ready
)
1128 return (DECL_INLINE (decl
) && !flag_really_no_inline
);
1129 /* Look if there is any clone around. */
1130 for (node
= cgraph_node (decl
); node
; node
= node
->next_clone
)
1131 if (node
->global
.inlined_to
)
1136 /* Perform simple optimizations based on callgraph. */
1139 cgraph_optimize (void)
1141 #ifdef ENABLE_CHECKING
1144 if (!flag_unit_at_a_time
)
1146 cgraph_varpool_assemble_pending_decls ();
1150 process_pending_assemble_externals ();
1152 /* Frontend may output common variables after the unit has been finalized.
1153 It is safe to deal with them here as they are always zero initialized. */
1154 cgraph_varpool_analyze_pending_decls ();
1156 timevar_push (TV_CGRAPHOPT
);
1158 fprintf (stderr
, "Performing intraprocedural optimizations\n");
1160 cgraph_function_and_variable_visibility ();
1161 if (cgraph_dump_file
)
1163 fprintf (cgraph_dump_file
, "Marked ");
1164 dump_cgraph (cgraph_dump_file
);
1167 /* This pass remove bodies of extern inline functions we never inlined.
1168 Do this later so other IPA passes see what is really going on. */
1169 cgraph_remove_unreachable_nodes (false, dump_file
);
1170 cgraph_global_info_ready
= true;
1171 if (cgraph_dump_file
)
1173 fprintf (cgraph_dump_file
, "Optimized ");
1174 dump_cgraph (cgraph_dump_file
);
1175 dump_varpool (cgraph_dump_file
);
1177 timevar_pop (TV_CGRAPHOPT
);
1179 /* Output everything. */
1181 fprintf (stderr
, "Assembling functions:\n");
1182 #ifdef ENABLE_CHECKING
1186 cgraph_mark_functions_to_output ();
1187 cgraph_expand_all_functions ();
1188 cgraph_varpool_remove_unreferenced_decls ();
1190 cgraph_varpool_assemble_pending_decls ();
1192 if (cgraph_dump_file
)
1194 fprintf (cgraph_dump_file
, "\nFinal ");
1195 dump_cgraph (cgraph_dump_file
);
1197 #ifdef ENABLE_CHECKING
1199 /* Double check that all inline clones are gone and that all
1200 function bodies have been released from memory. */
1201 if (flag_unit_at_a_time
1202 && !dump_enabled_p (TDI_tree_all
)
1203 && !(sorrycount
|| errorcount
))
1205 struct cgraph_node
*node
;
1206 bool error_found
= false;
1208 for (node
= cgraph_nodes
; node
; node
= node
->next
)
1210 && (node
->global
.inlined_to
1211 || DECL_SAVED_TREE (node
->decl
)))
1214 dump_cgraph_node (stderr
, node
);
1217 internal_error ("Nodes with no released memory found.");
1222 /* Generate and emit a static constructor or destructor. WHICH must be
1223 one of 'I' or 'D'. BODY should be a STATEMENT_LIST containing
1224 GENERIC statements. */
1227 cgraph_build_static_cdtor (char which
, tree body
, int priority
)
1229 static int counter
= 0;
1231 tree decl
, name
, resdecl
;
1233 sprintf (which_buf
, "%c_%d", which
, counter
++);
1234 name
= get_file_function_name_long (which_buf
);
1236 decl
= build_decl (FUNCTION_DECL
, name
,
1237 build_function_type (void_type_node
, void_list_node
));
1238 current_function_decl
= decl
;
1240 resdecl
= build_decl (RESULT_DECL
, NULL_TREE
, void_type_node
);
1241 DECL_ARTIFICIAL (resdecl
) = 1;
1242 DECL_IGNORED_P (resdecl
) = 1;
1243 DECL_RESULT (decl
) = resdecl
;
1245 allocate_struct_function (decl
);
1247 TREE_STATIC (decl
) = 1;
1248 TREE_USED (decl
) = 1;
1249 DECL_ARTIFICIAL (decl
) = 1;
1250 DECL_IGNORED_P (decl
) = 1;
1251 DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl
) = 1;
1252 DECL_SAVED_TREE (decl
) = body
;
1253 TREE_PUBLIC (decl
) = ! targetm
.have_ctors_dtors
;
1254 DECL_UNINLINABLE (decl
) = 1;
1256 DECL_INITIAL (decl
) = make_node (BLOCK
);
1257 TREE_USED (DECL_INITIAL (decl
)) = 1;
1259 DECL_SOURCE_LOCATION (decl
) = input_location
;
1260 cfun
->function_end_locus
= input_location
;
1265 DECL_STATIC_CONSTRUCTOR (decl
) = 1;
1268 DECL_STATIC_DESTRUCTOR (decl
) = 1;
1274 gimplify_function_tree (decl
);
1276 /* ??? We will get called LATE in the compilation process. */
1277 if (cgraph_global_info_ready
)
1279 tree_lowering_passes (decl
);
1280 tree_rest_of_compilation (decl
);
1283 cgraph_finalize_function (decl
, 0);
1285 if (targetm
.have_ctors_dtors
)
1287 void (*fn
) (rtx
, int);
1290 fn
= targetm
.asm_out
.constructor
;
1292 fn
= targetm
.asm_out
.destructor
;
1293 fn (XEXP (DECL_RTL (decl
), 0), priority
);
1300 cgraph_dump_file
= dump_begin (TDI_cgraph
, NULL
);