1 /* Nested function decomposition for trees.
2 Copyright (C) 2004 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"
29 #include "tree-dump.h"
30 #include "tree-inline.h"
31 #include "tree-gimple.h"
32 #include "tree-iterator.h"
33 #include "tree-flow.h"
36 #include "langhooks.h"
40 /* The object of this pass is to lower the representation of a set of nested
41 functions in order to expose all of the gory details of the various
42 nonlocal references. We want to do this sooner rather than later, in
43 order to give us more freedom in emitting all of the functions in question.
45 Back in olden times, when gcc was young, we developed an insanely
46 complicated scheme whereby variables which were referenced nonlocally
47 were forced to live in the stack of the declaring function, and then
48 the nested functions magically discovered where these variables were
49 placed. In order for this scheme to function properly, it required
50 that the outer function be partially expanded, then we switch to
51 compiling the inner function, and once done with those we switch back
52 to compiling the outer function. Such delicate ordering requirements
53 makes it difficult to do whole translation unit optimizations
54 involving such functions.
56 The implementation here is much more direct. Everything that can be
57 referenced by an inner function is a member of an explicitly created
58 structure herein called the "nonlocal frame struct". The incomming
59 static chain for a nested function is a pointer to this struct in
60 the parent. In this way, we settle on known offsets from a known
61 base, and so are decoupled from the logic that places objects in the
62 function's stack frame. More importantly, we don't have to wait for
63 that to happen -- since the compilation of the inner function is no
64 longer tied to a real stack frame, the nonlocal frame struct can be
65 allocated anywhere. Which means that the outer function is now
68 Theory of operation here is very simple. Iterate over all the
69 statements in all the functions (depth first) several times,
70 allocating structures and fields on demand. In general we want to
71 examine inner functions first, so that we can avoid making changes
72 to outer functions which are unnecessary.
74 The order of the passes matters a bit, in that later passes will be
75 skipped if it is discovered that the functions don't actually interact
76 at all. That is, they're nested in the lexical sense but could have
77 been written as independent functions without change. */
88 struct nesting_info *outer;
89 struct nesting_info *inner;
90 struct nesting_info *next;
94 tree new_local_var_chain;
101 bool any_parm_remapped;
102 bool any_tramp_created;
106 /* Hashing and equality functions for nesting_info->var_map. */
109 var_map_hash (const void *x)
111 const struct var_map_elt *a = x;
112 return htab_hash_pointer (a->old);
116 var_map_eq (const void *x, const void *y)
118 const struct var_map_elt *a = x;
119 const struct var_map_elt *b = y;
120 return a->old == b->old;
123 /* We're working in so many different function contexts simultaneously,
124 that create_tmp_var is dangerous. Prevent mishap. */
125 #define create_tmp_var cant_use_create_tmp_var_here_dummy
127 /* Like create_tmp_var, except record the variable for registration at
128 the given nesting level. */
131 create_tmp_var_for (struct nesting_info *info, tree type, const char *prefix)
135 #if defined ENABLE_CHECKING
136 /* If the type is of variable size or a type which must be created by the
137 frontend, something is wrong. Note that we explicitly allow
138 incomplete types here, since we create them ourselves here. */
139 if (TREE_ADDRESSABLE (type)
140 || (TYPE_SIZE_UNIT (type)
141 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST))
145 tmp_var = create_tmp_var_raw (type, prefix);
146 DECL_CONTEXT (tmp_var) = info->context;
147 TREE_CHAIN (tmp_var) = info->new_local_var_chain;
148 info->new_local_var_chain = tmp_var;
153 /* Take the address of EXP. Mark it for addressability as necessary. */
156 build_addr (tree exp)
160 while (TREE_CODE (base) == REALPART_EXPR || TREE_CODE (base) == IMAGPART_EXPR
161 || handled_component_p (base))
162 base = TREE_OPERAND (base, 0);
165 TREE_ADDRESSABLE (base) = 1;
167 return build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
170 /* Insert FIELD into TYPE, sorted by alignment requirements. */
173 insert_field_into_struct (tree type, tree field)
177 DECL_CONTEXT (field) = type;
179 for (p = &TYPE_FIELDS (type); *p ; p = &TREE_CHAIN (*p))
180 if (DECL_ALIGN (field) >= DECL_ALIGN (*p))
183 TREE_CHAIN (field) = *p;
187 /* Build or return the RECORD_TYPE that describes the frame state that is
188 shared between INFO->CONTEXT and its nested functions. This record will
189 not be complete until finalize_nesting_tree; up until that point we'll
190 be adding fields as necessary.
192 We also build the DECL that represents this frame in the function. */
195 get_frame_type (struct nesting_info *info)
197 tree type = info->frame_type;
202 type = make_node (RECORD_TYPE);
204 name = concat ("FRAME.",
205 IDENTIFIER_POINTER (DECL_NAME (info->context)),
207 TYPE_NAME (type) = get_identifier (name);
210 info->frame_type = type;
211 info->frame_decl = create_tmp_var_for (info, type, "FRAME");
216 /* Return true if DECL should be referenced by pointer in the non-local
220 use_pointer_in_frame (tree decl)
222 if (TREE_CODE (decl) == PARM_DECL)
224 /* It's illegal to copy TREE_ADDRESSABLE, impossible to copy variable
225 sized decls, and inefficient to copy large aggregates. Don't bother
226 moving anything but scalar variables. */
227 return AGGREGATE_TYPE_P (TREE_TYPE (decl));
231 /* Variable sized types make things "interesting" in the frame. */
232 return DECL_SIZE (decl) == NULL || !TREE_CONSTANT (DECL_SIZE (decl));
236 /* Given DECL, a non-locally accessed variable, find or create a field
237 in the non-local frame structure for the given nesting context. */
240 lookup_field_for_decl (struct nesting_info *info, tree decl,
241 enum insert_option insert)
243 struct var_map_elt *elt, dummy;
248 slot = htab_find_slot (info->var_map, &dummy, insert);
251 if (insert == INSERT)
257 if (!elt && insert == INSERT)
259 field = make_node (FIELD_DECL);
260 DECL_NAME (field) = DECL_NAME (decl);
262 if (use_pointer_in_frame (decl))
264 TREE_TYPE (field) = build_pointer_type (TREE_TYPE (decl));
265 DECL_ALIGN (field) = TYPE_ALIGN (TREE_TYPE (field));
266 DECL_NONADDRESSABLE_P (field) = 1;
270 TREE_TYPE (field) = TREE_TYPE (decl);
271 DECL_SOURCE_LOCATION (field) = DECL_SOURCE_LOCATION (decl);
272 DECL_ALIGN (field) = DECL_ALIGN (decl);
273 DECL_USER_ALIGN (field) = DECL_USER_ALIGN (decl);
274 TREE_ADDRESSABLE (field) = TREE_ADDRESSABLE (decl);
275 DECL_NONADDRESSABLE_P (field) = !TREE_ADDRESSABLE (decl);
276 TREE_THIS_VOLATILE (field) = TREE_THIS_VOLATILE (decl);
279 insert_field_into_struct (get_frame_type (info), field);
281 elt = xmalloc (sizeof (*elt));
286 if (TREE_CODE (decl) == PARM_DECL)
287 info->any_parm_remapped = true;
290 field = elt ? elt->new : NULL;
295 /* Build or return the variable that holds the static chain within
296 INFO->CONTEXT. This variable may only be used within INFO->CONTEXT. */
299 get_chain_decl (struct nesting_info *info)
301 tree decl = info->chain_decl;
306 type = get_frame_type (info->outer);
307 type = build_pointer_type (type);
309 /* Note that this variable is *not* entered into any BIND_EXPR;
310 the construction of this variable is handled specially in
311 expand_function_start and initialize_inlined_parameters.
312 Note also that it's represented as a parameter. This is more
313 close to the truth, since the initial value does come from
315 decl = build_decl (PARM_DECL, create_tmp_var_name ("CHAIN"), type);
316 DECL_ARTIFICIAL (decl) = 1;
317 DECL_IGNORED_P (decl) = 1;
318 TREE_USED (decl) = 1;
319 DECL_CONTEXT (decl) = info->context;
320 DECL_ARG_TYPE (decl) = type;
322 /* Tell tree-inline.c that we never write to this variable, so
323 it can copy-prop the replacement value immediately. */
324 TREE_READONLY (decl) = 1;
326 info->chain_decl = decl;
331 /* Build or return the field within the non-local frame state that holds
332 the static chain for INFO->CONTEXT. This is the way to walk back up
333 multiple nesting levels. */
336 get_chain_field (struct nesting_info *info)
338 tree field = info->chain_field;
341 tree type = build_pointer_type (get_frame_type (info->outer));
343 field = make_node (FIELD_DECL);
344 DECL_NAME (field) = get_identifier ("__chain");
345 TREE_TYPE (field) = type;
346 DECL_ALIGN (field) = TYPE_ALIGN (type);
347 DECL_NONADDRESSABLE_P (field) = 1;
349 insert_field_into_struct (get_frame_type (info), field);
351 info->chain_field = field;
356 /* Copy EXP into a temporary. Allocate the temporary in the context of
357 INFO and insert the initialization statement before TSI. */
360 init_tmp_var (struct nesting_info *info, tree exp, tree_stmt_iterator *tsi)
364 t = create_tmp_var_for (info, TREE_TYPE (exp), NULL);
365 stmt = build (MODIFY_EXPR, TREE_TYPE (t), t, exp);
366 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (tsi_stmt (*tsi)));
367 tsi_link_before (tsi, stmt, TSI_SAME_STMT);
372 /* Similarly, but only do so to force EXP to satisfy is_gimple_val. */
375 gimplify_val (struct nesting_info *info, tree exp, tree_stmt_iterator *tsi)
377 if (is_gimple_val (exp))
380 return init_tmp_var (info, exp, tsi);
383 /* Build or return the type used to represent a nested function trampoline. */
385 static GTY(()) tree trampoline_type;
388 get_trampoline_type (void)
391 unsigned align, size;
394 return trampoline_type;
396 align = TRAMPOLINE_ALIGNMENT;
397 size = TRAMPOLINE_SIZE;
399 /* If we won't be able to guarantee alignment simply via TYPE_ALIGN,
400 then allocate extra space so that we can do dynamic alignment. */
401 if (align > STACK_BOUNDARY)
403 size += ((align/BITS_PER_UNIT) - 1) & -(STACK_BOUNDARY/BITS_PER_UNIT);
404 align = STACK_BOUNDARY;
407 t = build_index_type (build_int_2 (size - 1, 0));
408 t = build_array_type (char_type_node, t);
409 t = build_decl (FIELD_DECL, get_identifier ("__data"), t);
410 DECL_ALIGN (t) = align;
411 DECL_USER_ALIGN (t) = 1;
413 record = make_node (RECORD_TYPE);
414 TYPE_NAME (record) = get_identifier ("__builtin_trampoline");
415 TYPE_FIELDS (record) = t;
416 layout_type (record);
421 /* Given DECL, a nested function, find or create a field in the non-local
422 frame structure for a trampoline for this function. */
425 lookup_tramp_for_decl (struct nesting_info *info, tree decl,
426 enum insert_option insert)
428 struct var_map_elt *elt, dummy;
433 slot = htab_find_slot (info->var_map, &dummy, insert);
436 if (insert == INSERT)
442 if (!elt && insert == INSERT)
444 field = make_node (FIELD_DECL);
445 DECL_NAME (field) = DECL_NAME (decl);
446 TREE_TYPE (field) = get_trampoline_type ();
447 TREE_ADDRESSABLE (field) = 1;
449 insert_field_into_struct (get_frame_type (info), field);
451 elt = xmalloc (sizeof (*elt));
456 info->any_tramp_created = true;
459 field = elt ? elt->new : NULL;
464 /* Build or return the field within the non-local frame state that holds
465 the non-local goto "jmp_buf". The buffer itself is maintained by the
466 rtl middle-end as dynamic stack space is allocated. */
469 get_nl_goto_field (struct nesting_info *info)
471 tree field = info->nl_goto_field;
477 /* For __builtin_nonlocal_goto, we need N words. The first is the
478 frame pointer, the rest is for the target's stack pointer save
479 area. The number of words is controlled by STACK_SAVEAREA_MODE;
480 not the best interface, but it'll do for now. */
481 if (Pmode == ptr_mode)
482 type = ptr_type_node;
484 type = lang_hooks.types.type_for_mode (Pmode, 1);
486 size = GET_MODE_SIZE (STACK_SAVEAREA_MODE (SAVE_NONLOCAL));
487 size = size / GET_MODE_SIZE (Pmode);
490 type = build_array_type (type, build_index_type (build_int_2 (size, 0)));
492 field = make_node (FIELD_DECL);
493 DECL_NAME (field) = get_identifier ("__nl_goto_buf");
494 TREE_TYPE (field) = type;
495 DECL_ALIGN (field) = TYPE_ALIGN (type);
496 TREE_ADDRESSABLE (field) = 1;
498 insert_field_into_struct (get_frame_type (info), field);
500 info->nl_goto_field = field;
506 /* Convenience routines to walk all statements of a gimple function.
508 For each statement, we invoke CALLBACK via walk_tree. The passed
509 data is a walk_stmt_info structure. Of note here is a TSI that
510 points to the current statement being walked. The VAL_ONLY flag
511 that indicates whether the *TP being examined may be replaced
512 with something that matches is_gimple_val (if true) or something
513 slightly more complicated (if false). "Something" technically
514 means the common subset of is_gimple_lvalue and is_gimple_rhs,
515 but we never try to form anything more complicated than that, so
516 we don't bother checking. */
518 struct walk_stmt_info
520 walk_tree_fn callback;
521 tree_stmt_iterator tsi;
522 struct nesting_info *info;
526 /* A subroutine of walk_function. Iterate over all sub-statements of *TP. */
529 walk_stmts (struct walk_stmt_info *wi, tree *tp)
535 switch (TREE_CODE (t))
539 tree_stmt_iterator i;
540 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
543 walk_stmts (wi, tsi_stmt_ptr (i));
549 walk_tree (&COND_EXPR_COND (t), wi->callback, wi, NULL);
550 walk_stmts (wi, &COND_EXPR_THEN (t));
551 walk_stmts (wi, &COND_EXPR_ELSE (t));
554 walk_stmts (wi, &CATCH_BODY (t));
557 walk_stmts (wi, &EH_FILTER_FAILURE (t));
560 case TRY_FINALLY_EXPR:
561 walk_stmts (wi, &TREE_OPERAND (t, 0));
562 walk_stmts (wi, &TREE_OPERAND (t, 1));
565 walk_stmts (wi, &BIND_EXPR_BODY (t));
569 walk_stmts (wi, &TREE_OPERAND (t, 0));
573 /* The immediate arguments of a MODIFY_EXPR may use COMPONENT_REF. */
574 wi->val_only = false;
575 walk_tree (&TREE_OPERAND (t, 0), wi->callback, wi, NULL);
576 wi->val_only = false;
577 walk_tree (&TREE_OPERAND (t, 1), wi->callback, wi, NULL);
583 walk_tree (tp, wi->callback, wi, NULL);
588 /* Invoke CALLBACK on all statements of INFO->CONTEXT. */
591 walk_function (walk_tree_fn callback, struct nesting_info *info)
593 struct walk_stmt_info wi;
595 memset (&wi, 0, sizeof (wi));
596 wi.callback = callback;
600 walk_stmts (&wi, &DECL_SAVED_TREE (info->context));
603 /* Similarly for ROOT and all functions nested underneath, depth first. */
606 walk_all_functions (walk_tree_fn callback, struct nesting_info *root)
611 walk_all_functions (callback, root->inner);
612 walk_function (callback, root);
619 /* Construct our local datastructure describing the function nesting
620 tree rooted by CGN. */
622 static struct nesting_info *
623 create_nesting_tree (struct cgraph_node *cgn)
625 struct nesting_info *info = xcalloc (1, sizeof (*info));
626 info->var_map = htab_create (7, var_map_hash, var_map_eq, free);
627 info->context = cgn->decl;
629 for (cgn = cgn->nested; cgn ; cgn = cgn->next_nested)
631 struct nesting_info *sub = create_nesting_tree (cgn);
633 sub->next = info->inner;
640 /* Return an expression computing the static chain for TARGET_CONTEXT
641 from INFO->CONTEXT. Insert any necessary computations before TSI. */
644 get_static_chain (struct nesting_info *info, tree target_context,
645 tree_stmt_iterator *tsi)
647 struct nesting_info *i;
650 if (info->context == target_context)
652 x = build_addr (info->frame_decl);
656 x = get_chain_decl (info);
658 for (i = info->outer; i->context != target_context; i = i->outer)
660 tree field = get_chain_field (i);
662 x = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (x)), x);
663 x = build (COMPONENT_REF, TREE_TYPE (field), x, field, NULL_TREE);
664 x = init_tmp_var (info, x, tsi);
671 /* Return an expression referencing FIELD from TARGET_CONTEXT's non-local
672 frame as seen from INFO->CONTEXT. Insert any necessary computations
676 get_frame_field (struct nesting_info *info, tree target_context,
677 tree field, tree_stmt_iterator *tsi)
679 struct nesting_info *i;
682 if (info->context == target_context)
684 /* Make sure frame_decl gets created. */
685 (void) get_frame_type (info);
686 x = info->frame_decl;
690 x = get_chain_decl (info);
692 for (i = info->outer; i->context != target_context; i = i->outer)
694 tree field = get_chain_field (i);
696 x = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (x)), x);
697 x = build (COMPONENT_REF, TREE_TYPE (field), x, field, NULL_TREE);
698 x = init_tmp_var (info, x, tsi);
701 x = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (x)), x);
704 x = build (COMPONENT_REF, TREE_TYPE (field), x, field, NULL_TREE);
708 /* Called via walk_function+walk_tree, rewrite all references to VAR
709 and PARM_DECLs that belong to outer functions.
711 The rewrite will involve some number of structure accesses back up
712 the static chain. E.g. for a variable FOO up one nesting level it'll
713 be CHAIN->FOO. For two levels it'll be CHAIN->__chain->FOO. Further
714 indirections apply to decls for which use_pointer_in_frame is true. */
717 convert_nonlocal_reference (tree *tp, int *walk_subtrees, void *data)
719 struct walk_stmt_info *wi = data;
720 struct nesting_info *info = wi->info;
724 switch (TREE_CODE (t))
727 /* Non-automatic variables are never processed. */
728 if (TREE_STATIC (t) || DECL_EXTERNAL (t))
733 if (decl_function_context (t) != info->context)
735 tree target_context = decl_function_context (t);
736 struct nesting_info *i;
739 for (i = info->outer; i->context != target_context; i = i->outer)
741 x = lookup_field_for_decl (i, t, INSERT);
742 x = get_frame_field (info, target_context, x, &wi->tsi);
743 if (use_pointer_in_frame (t))
745 x = init_tmp_var (info, x, &wi->tsi);
746 x = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (x)), x);
749 x = init_tmp_var (info, x, &wi->tsi);
756 /* Don't walk non-local gotos for now. */
757 if (TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL)
765 /* We're taking the address of a label from a parent function, but
766 this is not itself a non-local goto. Mark the label such that it
767 will not be deleted, much as we would with a label address in
769 if (decl_function_context (t) != info->context)
770 FORCED_LABEL (t) = 1;
775 bool save_val_only = wi->val_only;
776 tree save_sub = TREE_OPERAND (t, 0);
778 wi->val_only = false;
779 walk_tree (&TREE_OPERAND (t, 0), convert_nonlocal_reference, wi, NULL);
782 if (save_sub != TREE_OPERAND (t, 0))
784 /* If we changed anything, then TREE_INVARIANT is be wrong,
785 since we're no longer directly referencing a decl. */
786 TREE_INVARIANT (t) = 0;
788 /* If the callback converted the address argument in a context
789 where we only accept variables (and min_invariant, presumably),
790 then compute the address into a temporary. */
792 *tp = gimplify_val (wi->info, t, &wi->tsi);
801 case ARRAY_RANGE_REF:
803 /* Go down this entire nest and just look at the final prefix and
804 anything that describes the references. Otherwise, we lose track
805 of whether a NOP_EXPR or VIEW_CONVERT_EXPR needs a simple value. */
807 for (; handled_component_p (t)
808 || TREE_CODE (t) == REALPART_EXPR || TREE_CODE (t) == IMAGPART_EXPR;
809 tp = &TREE_OPERAND (t, 0), t = *tp)
811 if (TREE_CODE (t) == COMPONENT_REF)
812 walk_tree (&TREE_OPERAND (t, 2), convert_nonlocal_reference, wi,
814 else if (TREE_CODE (t) == ARRAY_REF
815 || TREE_CODE (t) == ARRAY_RANGE_REF)
817 walk_tree (&TREE_OPERAND (t, 1), convert_nonlocal_reference, wi,
819 walk_tree (&TREE_OPERAND (t, 2), convert_nonlocal_reference, wi,
821 walk_tree (&TREE_OPERAND (t, 3), convert_nonlocal_reference, wi,
824 else if (TREE_CODE (t) == BIT_FIELD_REF)
826 walk_tree (&TREE_OPERAND (t, 1), convert_nonlocal_reference, wi,
828 walk_tree (&TREE_OPERAND (t, 2), convert_nonlocal_reference, wi,
832 wi->val_only = false;
833 walk_tree (tp, convert_nonlocal_reference, wi, NULL);
837 if (!DECL_P (t) && !TYPE_P (t))
848 /* Called via walk_function+walk_tree, rewrite all references to VAR
849 and PARM_DECLs that were referenced by inner nested functions.
850 The rewrite will be a structure reference to the local frame variable. */
853 convert_local_reference (tree *tp, int *walk_subtrees, void *data)
855 struct walk_stmt_info *wi = data;
856 struct nesting_info *info = wi->info;
857 tree t = *tp, field, x, y;
859 switch (TREE_CODE (t))
862 /* Non-automatic variables are never processed. */
863 if (TREE_STATIC (t) || DECL_EXTERNAL (t))
868 if (decl_function_context (t) == info->context)
870 /* If we copied a pointer to the frame, then the original decl
871 is used unchanged in the parent function. */
872 if (use_pointer_in_frame (t))
875 /* No need to transform anything if no child references the
877 field = lookup_field_for_decl (info, t, NO_INSERT);
881 x = get_frame_field (info, info->context, field, &wi->tsi);
883 x = init_tmp_var (info, x, &wi->tsi);
890 bool save_val_only = wi->val_only;
891 tree save_sub = TREE_OPERAND (t, 0);
893 wi->val_only = false;
894 walk_tree (&TREE_OPERAND (t, 0), convert_local_reference, wi, NULL);
895 wi->val_only = save_val_only;
897 /* If we converted anything ... */
898 if (TREE_OPERAND (t, 0) != save_sub)
900 /* Then the frame decl is now addressable. */
901 TREE_ADDRESSABLE (info->frame_decl) = 1;
903 /* If we are in a context where we only accept values, then
904 compute the address into a temporary. */
906 *tp = gimplify_val (wi->info, t, &wi->tsi);
914 /* Ready for some fun? We need to recognize
915 __builtin_stack_alloc (&x, n)
918 after that. X should have use_pointer_in_frame set. We can't
919 do this any earlier, since we can't meaningfully evaluate &x. */
921 x = get_callee_fndecl (t);
922 if (!x || DECL_BUILT_IN_CLASS (x) != BUILT_IN_NORMAL)
924 if (DECL_FUNCTION_CODE (x) != BUILT_IN_STACK_ALLOC)
926 t = TREE_VALUE (TREE_OPERAND (t, 1));
927 if (TREE_CODE (t) != ADDR_EXPR)
929 t = TREE_OPERAND (t, 0);
930 if (TREE_CODE (t) != VAR_DECL)
932 field = lookup_field_for_decl (info, t, NO_INSERT);
935 if (!use_pointer_in_frame (t))
939 y = get_frame_field (info, info->context, field, &wi->tsi);
940 x = build (MODIFY_EXPR, void_type_node, y, x);
941 SET_EXPR_LOCUS (x, EXPR_LOCUS (tsi_stmt (wi->tsi)));
942 tsi_link_after (&wi->tsi, x, TSI_SAME_STMT);
949 case ARRAY_RANGE_REF:
951 /* Go down this entire nest and just look at the final prefix and
952 anything that describes the references. Otherwise, we lose track
953 of whether a NOP_EXPR or VIEW_CONVERT_EXPR needs a simple value. */
955 for (; handled_component_p (t)
956 || TREE_CODE (t) == REALPART_EXPR || TREE_CODE (t) == IMAGPART_EXPR;
957 tp = &TREE_OPERAND (t, 0), t = *tp)
959 if (TREE_CODE (t) == COMPONENT_REF)
960 walk_tree (&TREE_OPERAND (t, 2), convert_local_reference, wi,
962 else if (TREE_CODE (t) == ARRAY_REF
963 || TREE_CODE (t) == ARRAY_RANGE_REF)
965 walk_tree (&TREE_OPERAND (t, 1), convert_local_reference, wi,
967 walk_tree (&TREE_OPERAND (t, 2), convert_local_reference, wi,
969 walk_tree (&TREE_OPERAND (t, 3), convert_local_reference, wi,
972 else if (TREE_CODE (t) == BIT_FIELD_REF)
974 walk_tree (&TREE_OPERAND (t, 1), convert_local_reference, wi,
976 walk_tree (&TREE_OPERAND (t, 2), convert_local_reference, wi,
980 wi->val_only = false;
981 walk_tree (tp, convert_local_reference, wi, NULL);
985 if (!DECL_P (t) && !TYPE_P (t))
996 /* Called via walk_function+walk_tree, rewrite all GOTO_EXPRs that
997 reference labels from outer functions. The rewrite will be a
998 call to __builtin_nonlocal_goto. */
1001 convert_nl_goto_reference (tree *tp, int *walk_subtrees, void *data)
1003 struct walk_stmt_info *wi = data;
1004 struct nesting_info *info = wi->info, *i;
1005 tree t = *tp, label, new_label, target_context, x, arg, field;
1006 struct var_map_elt *elt;
1010 if (TREE_CODE (t) != GOTO_EXPR)
1012 label = GOTO_DESTINATION (t);
1013 if (TREE_CODE (label) != LABEL_DECL)
1015 target_context = decl_function_context (label);
1016 if (target_context == info->context)
1019 for (i = info->outer; target_context != i->context; i = i->outer)
1022 /* The original user label may also be use for a normal goto, therefore
1023 we must create a new label that will actually receive the abnormal
1024 control transfer. This new label will be marked LABEL_NONLOCAL; this
1025 mark will trigger proper behavior in the cfg, as well as cause the
1026 (hairy target-specific) non-local goto receiver code to be generated
1027 when we expand rtl. */
1028 new_label = create_artificial_label ();
1029 DECL_NONLOCAL (new_label) = 1;
1031 /* Enter this association into var_map so that we can insert the new
1032 label into the IL during a second pass. */
1033 elt = xmalloc (sizeof (*elt));
1035 elt->new = new_label;
1036 slot = htab_find_slot (i->var_map, elt, INSERT);
1039 /* Build: __builtin_nl_goto(new_label, &chain->nl_goto_field). */
1040 field = get_nl_goto_field (i);
1041 x = get_frame_field (info, target_context, field, &wi->tsi);
1043 x = gimplify_val (info, x, &wi->tsi);
1044 arg = tree_cons (NULL, x, NULL);
1045 x = build_addr (new_label);
1046 arg = tree_cons (NULL, x, arg);
1047 x = implicit_built_in_decls[BUILT_IN_NONLOCAL_GOTO];
1048 x = build_function_call_expr (x, arg);
1050 SET_EXPR_LOCUS (x, EXPR_LOCUS (tsi_stmt (wi->tsi)));
1051 *tsi_stmt_ptr (wi->tsi) = x;
1056 /* Called via walk_function+walk_tree, rewrite all LABEL_EXPRs that
1057 are referenced via nonlocal goto from a nested function. The rewrite
1058 will involve installing a newly generated DECL_NONLOCAL label, and
1059 (potentially) a branch around the rtl gunk that is assumed to be
1060 attached to such a label. */
1063 convert_nl_goto_receiver (tree *tp, int *walk_subtrees, void *data)
1065 struct walk_stmt_info *wi = data;
1066 struct nesting_info *info = wi->info;
1067 tree t = *tp, label, new_label, x;
1068 struct var_map_elt *elt, dummy;
1069 tree_stmt_iterator tmp_tsi;
1072 if (TREE_CODE (t) != LABEL_EXPR)
1074 label = LABEL_EXPR_LABEL (t);
1077 elt = htab_find (info->var_map, &dummy);
1080 new_label = elt->new;
1082 /* If there's any possibility that the previous statement falls through,
1083 then we must branch around the new non-local label. */
1085 tsi_prev (&tmp_tsi);
1086 if (tsi_end_p (tmp_tsi) || block_may_fallthru (tsi_stmt (tmp_tsi)))
1088 x = build1 (GOTO_EXPR, void_type_node, label);
1089 tsi_link_before (&wi->tsi, x, TSI_SAME_STMT);
1091 x = build1 (LABEL_EXPR, void_type_node, new_label);
1092 tsi_link_before (&wi->tsi, x, TSI_SAME_STMT);
1097 /* Called via walk_function+walk_tree, rewrite all references to addresses
1098 of nested functions that require the use of trampolines. The rewrite
1099 will involve a reference a trampoline generated for the occasion. */
1102 convert_tramp_reference (tree *tp, int *walk_subtrees, void *data)
1104 struct walk_stmt_info *wi = data;
1105 struct nesting_info *info = wi->info, *i;
1106 tree t = *tp, decl, target_context, x, arg;
1109 switch (TREE_CODE (t))
1113 T.1 = &CHAIN->tramp;
1114 T.2 = __builtin_adjust_trampoline (T.1);
1115 T.3 = (func_type)T.2;
1118 decl = TREE_OPERAND (t, 0);
1119 if (TREE_CODE (decl) != FUNCTION_DECL)
1122 /* Only need to process nested functions. */
1123 target_context = decl_function_context (decl);
1124 if (!target_context)
1127 /* If the nested function doesn't use a static chain, then
1128 it doesn't need a trampoline. */
1129 if (DECL_NO_STATIC_CHAIN (decl))
1132 /* Lookup the immediate parent of the callee, as that's where
1133 we need to insert the trampoline. */
1134 for (i = info; i->context != target_context; i = i->outer)
1136 x = lookup_tramp_for_decl (i, decl, INSERT);
1138 /* Compute the address of the field holding the trampoline. */
1139 x = get_frame_field (info, target_context, x, &wi->tsi);
1141 x = gimplify_val (info, x, &wi->tsi);
1142 arg = tree_cons (NULL, x, NULL);
1144 /* Do machine-specific ugliness. Normally this will involve
1145 computing extra alignment, but it can really be anything. */
1146 x = implicit_built_in_decls[BUILT_IN_ADJUST_TRAMPOLINE];
1147 x = build_function_call_expr (x, arg);
1148 x = init_tmp_var (info, x, &wi->tsi);
1150 /* Cast back to the proper function type. */
1151 x = build1 (NOP_EXPR, TREE_TYPE (t), x);
1152 x = init_tmp_var (info, x, &wi->tsi);
1158 /* Only walk call arguments, lest we generate trampolines for
1160 walk_tree (&TREE_OPERAND (t, 1), convert_tramp_reference, wi, NULL);
1164 if (!DECL_P (t) && !TYPE_P (t))
1172 /* Called via walk_function+walk_tree, rewrite all CALL_EXPRs that
1173 reference nested functions to make sure that the static chain is
1174 set up properly for the call. */
1177 convert_call_expr (tree *tp, int *walk_subtrees, void *data)
1179 struct walk_stmt_info *wi = data;
1180 struct nesting_info *info = wi->info;
1181 tree t = *tp, decl, target_context;
1184 switch (TREE_CODE (t))
1187 decl = get_callee_fndecl (t);
1190 target_context = decl_function_context (decl);
1191 if (target_context && !DECL_NO_STATIC_CHAIN (decl))
1193 = get_static_chain (info, target_context, &wi->tsi);
1198 /* Only return and modify may contain calls. */
1209 /* Walk the nesting tree starting with ROOT, depth first. Convert all
1210 trampolines and call expressions. On the way back up, determine if
1211 a nested function actually uses its static chain; if not, remember that. */
1214 convert_all_function_calls (struct nesting_info *root)
1219 convert_all_function_calls (root->inner);
1221 walk_function (convert_tramp_reference, root);
1222 walk_function (convert_call_expr, root);
1224 /* If the function does not use a static chain, then remember that. */
1225 if (root->outer && !root->chain_decl && !root->chain_field)
1226 DECL_NO_STATIC_CHAIN (root->context) = 1;
1229 #ifdef ENABLE_CHECKING
1230 if (DECL_NO_STATIC_CHAIN (root->context))
1240 /* Do "everything else" to clean up or complete state collected by the
1241 various walking passes -- lay out the types and decls, generate code
1242 to initialize the frame decl, store critical expressions in the
1243 struct function for rtl to find. */
1246 finalize_nesting_tree_1 (struct nesting_info *root)
1248 tree stmt_list = NULL;
1249 tree context = root->context;
1250 struct function *sf;
1252 /* If we created a non-local frame type or decl, we need to lay them
1253 out at this time. */
1254 if (root->frame_type)
1256 layout_type (root->frame_type);
1257 layout_decl (root->frame_decl, 0);
1260 /* If any parameters were referenced non-locally, then we need to
1261 insert a copy. Likewise, if any variables were referenced by
1262 pointer, we need to initialize the address. */
1263 if (root->any_parm_remapped)
1266 for (p = DECL_ARGUMENTS (context); p ; p = TREE_CHAIN (p))
1270 field = lookup_field_for_decl (root, p, NO_INSERT);
1274 if (use_pointer_in_frame (p))
1279 y = build (COMPONENT_REF, TREE_TYPE (field),
1280 root->frame_decl, field, NULL_TREE);
1281 x = build (MODIFY_EXPR, TREE_TYPE (field), y, x);
1282 append_to_statement_list (x, &stmt_list);
1286 /* If a chain_field was created, then it needs to be initialized
1288 if (root->chain_field)
1290 tree x = build (COMPONENT_REF, TREE_TYPE (root->chain_field),
1291 root->frame_decl, root->chain_field, NULL_TREE);
1292 x = build (MODIFY_EXPR, TREE_TYPE (x), x, get_chain_decl (root));
1293 append_to_statement_list (x, &stmt_list);
1296 /* If trampolines were created, then we need to initialize them. */
1297 if (root->any_tramp_created)
1299 struct nesting_info *i;
1300 for (i = root->inner; i ; i = i->next)
1304 field = lookup_tramp_for_decl (root, i->context, NO_INSERT);
1308 if (DECL_NO_STATIC_CHAIN (i->context))
1309 x = null_pointer_node;
1311 x = build_addr (root->frame_decl);
1312 arg = tree_cons (NULL, x, NULL);
1314 x = build_addr (i->context);
1315 arg = tree_cons (NULL, x, arg);
1317 x = build (COMPONENT_REF, TREE_TYPE (field),
1318 root->frame_decl, field, NULL_TREE);
1320 arg = tree_cons (NULL, x, arg);
1322 x = implicit_built_in_decls[BUILT_IN_INIT_TRAMPOLINE];
1323 x = build_function_call_expr (x, arg);
1325 append_to_statement_list (x, &stmt_list);
1329 /* If we created initialization statements, insert them. */
1332 annotate_all_with_locus (&stmt_list,
1333 DECL_SOURCE_LOCATION (context));
1334 append_to_statement_list (BIND_EXPR_BODY (DECL_SAVED_TREE (context)),
1336 BIND_EXPR_BODY (DECL_SAVED_TREE (context)) = stmt_list;
1339 /* If a chain_decl was created, then it needs to be registered with
1340 struct function so that it gets initialized from the static chain
1341 register at the beginning of the function. */
1342 sf = DECL_STRUCT_FUNCTION (root->context);
1343 sf->static_chain_decl = root->chain_decl;
1345 /* Similarly for the non-local goto save area. */
1346 if (root->nl_goto_field)
1348 sf->nonlocal_goto_save_area
1349 = get_frame_field (root, context, root->nl_goto_field, NULL);
1350 sf->has_nonlocal_label = 1;
1353 /* Make sure all new local variables get inserted into the
1354 proper BIND_EXPR. */
1355 if (root->new_local_var_chain)
1356 declare_tmp_vars (root->new_local_var_chain,
1357 DECL_SAVED_TREE (root->context));
1359 /* Dump the translated tree function. */
1360 dump_function (TDI_nested, root->context);
1364 finalize_nesting_tree (struct nesting_info *root)
1369 finalize_nesting_tree (root->inner);
1370 finalize_nesting_tree_1 (root);
1376 /* Free the data structures allocated during this pass. */
1379 free_nesting_tree (struct nesting_info *root)
1381 struct nesting_info *next;
1385 free_nesting_tree (root->inner);
1386 htab_delete (root->var_map);
1394 /* Main entry point for this pass. Process FNDECL and all of its nested
1395 subroutines and turn them into something less tightly bound. */
1398 lower_nested_functions (tree fndecl)
1400 struct nesting_info *root;
1401 struct cgraph_node *cgn;
1403 /* If there are no nested functions, there's nothing to do. */
1404 cgn = cgraph_node (fndecl);
1408 root = create_nesting_tree (cgn);
1409 walk_all_functions (convert_nonlocal_reference, root);
1410 walk_all_functions (convert_local_reference, root);
1411 walk_all_functions (convert_nl_goto_reference, root);
1412 walk_all_functions (convert_nl_goto_receiver, root);
1413 convert_all_function_calls (root);
1414 finalize_nesting_tree (root);
1415 free_nesting_tree (root);
1418 #include "gt-tree-nested.h"