1 /* Mudflap: narrow-pointer bounds-checking by tree rewriting.
2 Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007
3 Free Software Foundation, Inc.
4 Contributed by Frank Ch. Eigler <fche@redhat.com>
5 and Graydon Hoare <graydon@redhat.com>
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify it under
10 the terms of the GNU General Public License as published by the Free
11 Software Foundation; either version 2, or (at your option) any later
14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING. If not, write to the Free
21 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
27 #include "coretypes.h"
29 #include "hard-reg-set.h"
33 #include "basic-block.h"
36 #include "tree-inline.h"
37 #include "tree-gimple.h"
38 #include "tree-flow.h"
39 #include "tree-mudflap.h"
40 #include "tree-dump.h"
41 #include "tree-pass.h"
43 #include "diagnostic.h"
45 #include "langhooks.h"
50 /* Internal function decls */
54 #define flag_mudflap_threads (flag_mudflap == 2)
57 static tree mf_build_string (const char *string);
58 static tree mf_varname_tree (tree);
59 static tree mf_file_function_line_tree (location_t);
61 /* Indirection-related instrumentation. */
62 static void mf_decl_cache_locals (void);
63 static void mf_decl_clear_locals (void);
64 static void mf_xform_derefs (void);
65 static unsigned int execute_mudflap_function_ops (void);
67 /* Addressable variables instrumentation. */
68 static void mf_xform_decls (tree, tree);
69 static tree mx_xfn_xform_decls (tree *, int *, void *);
70 static void mx_register_decls (tree, tree *);
71 static unsigned int execute_mudflap_function_decls (void);
74 /* ------------------------------------------------------------------------ */
75 /* Some generally helpful functions for mudflap instrumentation. */
77 /* Build a reference to a literal string. */
79 mf_build_string (const char *string)
81 size_t len = strlen (string);
82 tree result = mf_mark (build_string (len + 1, string));
84 TREE_TYPE (result) = build_array_type
85 (char_type_node, build_index_type (build_int_cst (NULL_TREE, len)));
86 TREE_CONSTANT (result) = 1;
87 TREE_INVARIANT (result) = 1;
88 TREE_READONLY (result) = 1;
89 TREE_STATIC (result) = 1;
91 result = build1 (ADDR_EXPR, build_pointer_type (char_type_node), result);
93 return mf_mark (result);
96 /* Create a properly typed STRING_CST node that describes the given
97 declaration. It will be used as an argument for __mf_register().
98 Try to construct a helpful string, including file/function/variable
102 mf_varname_tree (tree decl)
104 static pretty_printer buf_rec;
105 static int initialized = 0;
106 pretty_printer *buf = & buf_rec;
107 const char *buf_contents;
114 pp_construct (buf, /* prefix */ NULL, /* line-width */ 0);
117 pp_clear_output_area (buf);
119 /* Add FILENAME[:LINENUMBER[:COLUMNNUMBER]]. */
121 expanded_location xloc = expand_location (DECL_SOURCE_LOCATION (decl));
122 const char *sourcefile;
123 unsigned sourceline = xloc.line;
124 unsigned sourcecolumn = 0;
125 #ifdef USE_MAPPED_LOCATION
126 sourcecolumn = xloc.column;
128 sourcefile = xloc.file;
129 if (sourcefile == NULL && current_function_decl != NULL_TREE)
130 sourcefile = DECL_SOURCE_FILE (current_function_decl);
131 if (sourcefile == NULL)
132 sourcefile = "<unknown file>";
134 pp_string (buf, sourcefile);
138 pp_string (buf, ":");
139 pp_decimal_int (buf, sourceline);
141 if (sourcecolumn != 0)
143 pp_string (buf, ":");
144 pp_decimal_int (buf, sourcecolumn);
149 if (current_function_decl != NULL_TREE)
152 pp_string (buf, " (");
154 const char *funcname = NULL;
155 if (DECL_NAME (current_function_decl))
156 funcname = lang_hooks.decl_printable_name (current_function_decl, 1);
157 if (funcname == NULL)
158 funcname = "anonymous fn";
160 pp_string (buf, funcname);
162 pp_string (buf, ") ");
165 pp_string (buf, " ");
167 /* Add <variable-declaration>, possibly demangled. */
169 const char *declname = NULL;
171 if (DECL_NAME (decl) != NULL)
173 if (strcmp ("GNU C++", lang_hooks.name) == 0)
175 /* The gcc/cp decl_printable_name hook doesn't do as good a job as
176 the libiberty demangler. */
177 declname = cplus_demangle (IDENTIFIER_POINTER (DECL_NAME (decl)),
178 DMGL_AUTO | DMGL_VERBOSE);
180 if (declname == NULL)
181 declname = lang_hooks.decl_printable_name (decl, 3);
183 if (declname == NULL)
184 declname = "<unnamed variable>";
186 pp_string (buf, declname);
189 /* Return the lot as a new STRING_CST. */
190 buf_contents = pp_base_formatted_text (buf);
191 result = mf_build_string (buf_contents);
192 pp_clear_output_area (buf);
198 /* And another friend, for producing a simpler message. */
201 mf_file_function_line_tree (location_t location)
203 expanded_location xloc = expand_location (location);
204 const char *file = NULL, *colon, *line, *op, *name, *cp;
205 char linecolbuf[30]; /* Enough for two decimal numbers plus a colon. */
209 /* Add FILENAME[:LINENUMBER[:COLUMNNUMBER]]. */
211 if (file == NULL && current_function_decl != NULL_TREE)
212 file = DECL_SOURCE_FILE (current_function_decl);
214 file = "<unknown file>";
218 #ifdef USE_MAPPED_LOCATION
220 sprintf (linecolbuf, "%d:%d", xloc.line, xloc.column);
223 sprintf (linecolbuf, "%d", xloc.line);
230 /* Add (FUNCTION). */
231 name = lang_hooks.decl_printable_name (current_function_decl, 1);
240 string = concat (file, colon, line, op, name, cp, NULL);
241 result = mf_build_string (string);
248 /* global tree nodes */
250 /* Global tree objects for global variables and functions exported by
251 mudflap runtime library. mf_init_extern_trees must be called
252 before using these. */
254 /* uintptr_t (usually "unsigned long") */
255 static GTY (()) tree mf_uintptr_type;
257 /* struct __mf_cache { uintptr_t low; uintptr_t high; }; */
258 static GTY (()) tree mf_cache_struct_type;
260 /* struct __mf_cache * const */
261 static GTY (()) tree mf_cache_structptr_type;
263 /* extern struct __mf_cache __mf_lookup_cache []; */
264 static GTY (()) tree mf_cache_array_decl;
266 /* extern unsigned char __mf_lc_shift; */
267 static GTY (()) tree mf_cache_shift_decl;
269 /* extern uintptr_t __mf_lc_mask; */
270 static GTY (()) tree mf_cache_mask_decl;
272 /* Their function-scope local shadows, used in single-threaded mode only. */
274 /* auto const unsigned char __mf_lc_shift_l; */
275 static GTY (()) tree mf_cache_shift_decl_l;
277 /* auto const uintptr_t __mf_lc_mask_l; */
278 static GTY (()) tree mf_cache_mask_decl_l;
280 /* extern void __mf_check (void *ptr, size_t sz, int type, const char *); */
281 static GTY (()) tree mf_check_fndecl;
283 /* extern void __mf_register (void *ptr, size_t sz, int type, const char *); */
284 static GTY (()) tree mf_register_fndecl;
286 /* extern void __mf_unregister (void *ptr, size_t sz, int type); */
287 static GTY (()) tree mf_unregister_fndecl;
289 /* extern void __mf_init (); */
290 static GTY (()) tree mf_init_fndecl;
292 /* extern int __mf_set_options (const char*); */
293 static GTY (()) tree mf_set_options_fndecl;
296 /* Helper for mudflap_init: construct a decl with the given category,
297 name, and type, mark it an external reference, and pushdecl it. */
299 mf_make_builtin (enum tree_code category, const char *name, tree type)
301 tree decl = mf_mark (build_decl (category, get_identifier (name), type));
302 TREE_PUBLIC (decl) = 1;
303 DECL_EXTERNAL (decl) = 1;
304 lang_hooks.decls.pushdecl (decl);
308 /* Helper for mudflap_init: construct a tree corresponding to the type
309 struct __mf_cache { uintptr_t low; uintptr_t high; };
310 where uintptr_t is the FIELD_TYPE argument. */
312 mf_make_mf_cache_struct_type (tree field_type)
314 /* There is, abominably, no language-independent way to construct a
315 RECORD_TYPE. So we have to call the basic type construction
316 primitives by hand. */
317 tree fieldlo = build_decl (FIELD_DECL, get_identifier ("low"), field_type);
318 tree fieldhi = build_decl (FIELD_DECL, get_identifier ("high"), field_type);
320 tree struct_type = make_node (RECORD_TYPE);
321 DECL_CONTEXT (fieldlo) = struct_type;
322 DECL_CONTEXT (fieldhi) = struct_type;
323 TREE_CHAIN (fieldlo) = fieldhi;
324 TYPE_FIELDS (struct_type) = fieldlo;
325 TYPE_NAME (struct_type) = get_identifier ("__mf_cache");
326 layout_type (struct_type);
331 #define build_function_type_0(rtype) \
332 build_function_type (rtype, void_list_node)
333 #define build_function_type_1(rtype, arg1) \
334 build_function_type (rtype, tree_cons (0, arg1, void_list_node))
335 #define build_function_type_3(rtype, arg1, arg2, arg3) \
336 build_function_type (rtype, \
337 tree_cons (0, arg1, \
338 tree_cons (0, arg2, \
339 tree_cons (0, arg3, \
341 #define build_function_type_4(rtype, arg1, arg2, arg3, arg4) \
342 build_function_type (rtype, \
343 tree_cons (0, arg1, \
344 tree_cons (0, arg2, \
345 tree_cons (0, arg3, \
346 tree_cons (0, arg4, \
349 /* Initialize the global tree nodes that correspond to mf-runtime.h
354 static bool done = false;
355 tree mf_const_string_type;
356 tree mf_cache_array_type;
357 tree mf_check_register_fntype;
358 tree mf_unregister_fntype;
360 tree mf_set_options_fntype;
366 mf_uintptr_type = lang_hooks.types.type_for_mode (ptr_mode,
369 = build_pointer_type (build_qualified_type
370 (char_type_node, TYPE_QUAL_CONST));
372 mf_cache_struct_type = mf_make_mf_cache_struct_type (mf_uintptr_type);
373 mf_cache_structptr_type = build_pointer_type (mf_cache_struct_type);
374 mf_cache_array_type = build_array_type (mf_cache_struct_type, 0);
375 mf_check_register_fntype =
376 build_function_type_4 (void_type_node, ptr_type_node, size_type_node,
377 integer_type_node, mf_const_string_type);
378 mf_unregister_fntype =
379 build_function_type_3 (void_type_node, ptr_type_node, size_type_node,
382 build_function_type_0 (void_type_node);
383 mf_set_options_fntype =
384 build_function_type_1 (integer_type_node, mf_const_string_type);
386 mf_cache_array_decl = mf_make_builtin (VAR_DECL, "__mf_lookup_cache",
387 mf_cache_array_type);
388 mf_cache_shift_decl = mf_make_builtin (VAR_DECL, "__mf_lc_shift",
389 unsigned_char_type_node);
390 mf_cache_mask_decl = mf_make_builtin (VAR_DECL, "__mf_lc_mask",
392 /* Don't process these in mudflap_enqueue_decl, should they come by
393 there for some reason. */
394 mf_mark (mf_cache_array_decl);
395 mf_mark (mf_cache_shift_decl);
396 mf_mark (mf_cache_mask_decl);
397 mf_check_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_check",
398 mf_check_register_fntype);
399 mf_register_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_register",
400 mf_check_register_fntype);
401 mf_unregister_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_unregister",
402 mf_unregister_fntype);
403 mf_init_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_init",
405 mf_set_options_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_set_options",
406 mf_set_options_fntype);
408 #undef build_function_type_4
409 #undef build_function_type_3
410 #undef build_function_type_1
411 #undef build_function_type_0
414 /* ------------------------------------------------------------------------ */
415 /* Memory reference transforms. Perform the mudflap indirection-related
416 tree transforms on the current function.
418 This is the second part of the mudflap instrumentation. It works on
419 low-level GIMPLE using the CFG, because we want to run this pass after
420 tree optimizations have been performed, but we have to preserve the CFG
421 for expansion from trees to RTL. */
424 execute_mudflap_function_ops (void)
426 /* Don't instrument functions such as the synthetic constructor
427 built during mudflap_finish_file. */
428 if (mf_marked_p (current_function_decl) ||
429 DECL_ARTIFICIAL (current_function_decl))
432 push_gimplify_context ();
434 /* In multithreaded mode, don't cache the lookup cache parameters. */
435 if (! flag_mudflap_threads)
436 mf_decl_cache_locals ();
440 if (! flag_mudflap_threads)
441 mf_decl_clear_locals ();
443 pop_gimplify_context (NULL);
447 /* Create and initialize local shadow variables for the lookup cache
448 globals. Put their decls in the *_l globals for use by
449 mf_build_check_statement_for. */
452 mf_decl_cache_locals (void)
454 tree t, shift_init_stmts, mask_init_stmts;
455 tree_stmt_iterator tsi;
457 /* Build the cache vars. */
458 mf_cache_shift_decl_l
459 = mf_mark (create_tmp_var (TREE_TYPE (mf_cache_shift_decl),
460 "__mf_lookup_shift_l"));
463 = mf_mark (create_tmp_var (TREE_TYPE (mf_cache_mask_decl),
464 "__mf_lookup_mask_l"));
466 /* Build initialization nodes for the cache vars. We just load the
467 globals into the cache variables. */
468 t = build_gimple_modify_stmt (mf_cache_shift_decl_l, mf_cache_shift_decl);
469 SET_EXPR_LOCATION (t, DECL_SOURCE_LOCATION (current_function_decl));
470 gimplify_to_stmt_list (&t);
471 shift_init_stmts = t;
473 t = build_gimple_modify_stmt (mf_cache_mask_decl_l, mf_cache_mask_decl);
474 SET_EXPR_LOCATION (t, DECL_SOURCE_LOCATION (current_function_decl));
475 gimplify_to_stmt_list (&t);
478 /* Anticipating multiple entry points, we insert the cache vars
479 initializers in each successor of the ENTRY_BLOCK_PTR. */
480 for (tsi = tsi_start (shift_init_stmts);
483 insert_edge_copies (tsi_stmt (tsi), ENTRY_BLOCK_PTR);
485 for (tsi = tsi_start (mask_init_stmts);
488 insert_edge_copies (tsi_stmt (tsi), ENTRY_BLOCK_PTR);
489 bsi_commit_edge_inserts ();
494 mf_decl_clear_locals (void)
496 /* Unset local shadows. */
497 mf_cache_shift_decl_l = NULL_TREE;
498 mf_cache_mask_decl_l = NULL_TREE;
502 mf_build_check_statement_for (tree base, tree limit,
503 block_stmt_iterator *instr_bsi,
504 location_t *locus, tree dirflag)
506 tree_stmt_iterator head, tsi;
507 block_stmt_iterator bsi;
508 basic_block cond_bb, then_bb, join_bb;
515 /* We first need to split the current basic block, and start altering
516 the CFG. This allows us to insert the statements we're about to
517 construct into the right basic blocks. */
519 cond_bb = bb_for_stmt (bsi_stmt (*instr_bsi));
522 if (! bsi_end_p (bsi))
523 e = split_block (cond_bb, bsi_stmt (bsi));
525 e = split_block_after_labels (cond_bb);
529 /* A recap at this point: join_bb is the basic block at whose head
530 is the gimple statement for which this check expression is being
531 built. cond_bb is the (possibly new, synthetic) basic block the
532 end of which will contain the cache-lookup code, and a
533 conditional that jumps to the cache-miss code or, much more
534 likely, over to join_bb. */
536 /* Create the bb that contains the cache-miss fallback block (mf_check). */
537 then_bb = create_empty_bb (cond_bb);
538 make_edge (cond_bb, then_bb, EDGE_TRUE_VALUE);
539 make_single_succ_edge (then_bb, join_bb, EDGE_FALLTHRU);
541 /* Mark the pseudo-fallthrough edge from cond_bb to join_bb. */
542 e = find_edge (cond_bb, join_bb);
543 e->flags = EDGE_FALSE_VALUE;
544 e->count = cond_bb->count;
545 e->probability = REG_BR_PROB_BASE;
547 /* Update dominance info. Note that bb_join's data was
548 updated by split_block. */
549 if (dom_info_available_p (CDI_DOMINATORS))
551 set_immediate_dominator (CDI_DOMINATORS, then_bb, cond_bb);
552 set_immediate_dominator (CDI_DOMINATORS, join_bb, cond_bb);
555 /* Build our local variables. */
556 mf_elem = create_tmp_var (mf_cache_structptr_type, "__mf_elem");
557 mf_base = create_tmp_var (mf_uintptr_type, "__mf_base");
558 mf_limit = create_tmp_var (mf_uintptr_type, "__mf_limit");
560 /* Build: __mf_base = (uintptr_t) <base address expression>. */
561 t = build_gimple_modify_stmt (mf_base,
562 fold_convert (mf_uintptr_type,
563 unshare_expr (base)));
564 SET_EXPR_LOCUS (t, locus);
565 gimplify_to_stmt_list (&t);
566 head = tsi_start (t);
569 /* Build: __mf_limit = (uintptr_t) <limit address expression>. */
570 t = build_gimple_modify_stmt (mf_limit,
571 fold_convert (mf_uintptr_type,
572 unshare_expr (limit)));
573 SET_EXPR_LOCUS (t, locus);
574 gimplify_to_stmt_list (&t);
575 tsi_link_after (&tsi, t, TSI_CONTINUE_LINKING);
577 /* Build: __mf_elem = &__mf_lookup_cache [(__mf_base >> __mf_shift)
579 t = build2 (RSHIFT_EXPR, mf_uintptr_type, mf_base,
580 flag_mudflap_threads ? mf_cache_shift_decl
581 : mf_cache_shift_decl_l);
582 t = build2 (BIT_AND_EXPR, mf_uintptr_type, t,
583 flag_mudflap_threads ? mf_cache_mask_decl
584 : mf_cache_mask_decl_l);
585 t = build4 (ARRAY_REF,
586 TREE_TYPE (TREE_TYPE (mf_cache_array_decl)),
587 mf_cache_array_decl, t, NULL_TREE, NULL_TREE);
588 t = build1 (ADDR_EXPR, mf_cache_structptr_type, t);
589 t = build_gimple_modify_stmt (mf_elem, t);
590 SET_EXPR_LOCUS (t, locus);
591 gimplify_to_stmt_list (&t);
592 tsi_link_after (&tsi, t, TSI_CONTINUE_LINKING);
594 /* Quick validity check.
596 if (__mf_elem->low > __mf_base
597 || (__mf_elem_high < __mf_limit))
600 ... and only if single-threaded:
601 __mf_lookup_shift_1 = f...;
602 __mf_lookup_mask_l = ...;
605 It is expected that this body of code is rarely executed so we mark
606 the edge to the THEN clause of the conditional jump as unlikely. */
608 /* Construct t <-- '__mf_elem->low > __mf_base'. */
609 t = build3 (COMPONENT_REF, mf_uintptr_type,
610 build1 (INDIRECT_REF, mf_cache_struct_type, mf_elem),
611 TYPE_FIELDS (mf_cache_struct_type), NULL_TREE);
612 t = build2 (GT_EXPR, boolean_type_node, t, mf_base);
614 /* Construct '__mf_elem->high < __mf_limit'.
617 1) u <-- '__mf_elem->high'
618 2) v <-- '__mf_limit'.
620 Then build 'u <-- (u < v). */
622 u = build3 (COMPONENT_REF, mf_uintptr_type,
623 build1 (INDIRECT_REF, mf_cache_struct_type, mf_elem),
624 TREE_CHAIN (TYPE_FIELDS (mf_cache_struct_type)), NULL_TREE);
628 u = build2 (LT_EXPR, boolean_type_node, u, v);
630 /* Build the composed conditional: t <-- 't || u'. Then store the
631 result of the evaluation of 't' in a temporary variable which we
632 can use as the condition for the conditional jump. */
633 t = build2 (TRUTH_OR_EXPR, boolean_type_node, t, u);
634 cond = create_tmp_var (boolean_type_node, "__mf_unlikely_cond");
635 t = build_gimple_modify_stmt (cond, t);
636 gimplify_to_stmt_list (&t);
637 tsi_link_after (&tsi, t, TSI_CONTINUE_LINKING);
639 /* Build the conditional jump. 'cond' is just a temporary so we can
640 simply build a void COND_EXPR. We do need labels in both arms though. */
641 t = build3 (COND_EXPR, void_type_node, cond, NULL_TREE, NULL_TREE);
642 SET_EXPR_LOCUS (t, locus);
643 tsi_link_after (&tsi, t, TSI_CONTINUE_LINKING);
645 /* At this point, after so much hard work, we have only constructed
646 the conditional jump,
648 if (__mf_elem->low > __mf_base
649 || (__mf_elem_high < __mf_limit))
651 The lowered GIMPLE tree representing this code is in the statement
652 list starting at 'head'.
654 We can insert this now in the current basic block, i.e. the one that
655 the statement we're instrumenting was originally in. */
656 bsi = bsi_last (cond_bb);
657 for (tsi = head; ! tsi_end_p (tsi); tsi_next (&tsi))
658 bsi_insert_after (&bsi, tsi_stmt (tsi), BSI_CONTINUE_LINKING);
660 /* Now build up the body of the cache-miss handling:
665 This is the body of the conditional. */
667 u = mf_file_function_line_tree (locus == NULL ? UNKNOWN_LOCATION : *locus);
668 /* NB: we pass the overall [base..limit] range to mf_check. */
669 v = fold_build2 (PLUS_EXPR, integer_type_node,
670 fold_build2 (MINUS_EXPR, mf_uintptr_type, mf_limit, mf_base),
672 t = build_call_expr (mf_check_fndecl, 4, mf_base, v, dirflag, u);
673 gimplify_to_stmt_list (&t);
674 head = tsi_start (t);
677 if (! flag_mudflap_threads)
679 t = build_gimple_modify_stmt (mf_cache_shift_decl_l,
680 mf_cache_shift_decl);
681 tsi_link_after (&tsi, t, TSI_CONTINUE_LINKING);
683 t = build_gimple_modify_stmt (mf_cache_mask_decl_l,
685 tsi_link_after (&tsi, t, TSI_CONTINUE_LINKING);
688 /* Insert the check code in the THEN block. */
689 bsi = bsi_start (then_bb);
690 for (tsi = head; ! tsi_end_p (tsi); tsi_next (&tsi))
691 bsi_insert_after (&bsi, tsi_stmt (tsi), BSI_CONTINUE_LINKING);
693 *instr_bsi = bsi_start (join_bb);
697 /* Check whether the given decl, generally a VAR_DECL or PARM_DECL, is
698 eligible for instrumentation. For the mudflap1 pass, this implies
699 that it should be registered with the libmudflap runtime. For the
700 mudflap2 pass this means instrumenting an indirection operation with
701 respect to the object.
704 mf_decl_eligible_p (tree decl)
706 return ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
707 /* The decl must have its address taken. In the case of
708 arrays, this flag is also set if the indexes are not
709 compile-time known valid constants. */
710 /* XXX: not sufficient: return-by-value structs! */
711 && TREE_ADDRESSABLE (decl)
712 /* The type of the variable must be complete. */
713 && COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (decl))
714 /* The decl hasn't been decomposed somehow. */
715 && !DECL_HAS_VALUE_EXPR_P (decl));
720 mf_xform_derefs_1 (block_stmt_iterator *iter, tree *tp,
721 location_t *locus, tree dirflag)
723 tree type, base, limit, addr, size, t;
725 /* Don't instrument read operations. */
726 if (dirflag == integer_zero_node && flag_mudflap_ignore_reads)
729 /* Don't instrument marked nodes. */
730 if (mf_marked_p (*tp))
734 type = TREE_TYPE (t);
736 if (type == error_mark_node)
739 size = TYPE_SIZE_UNIT (type);
741 switch (TREE_CODE (t))
746 /* This is trickier than it may first appear. The reason is
747 that we are looking at expressions from the "inside out" at
748 this point. We may have a complex nested aggregate/array
749 expression (e.g. "a.b[i].c"), maybe with an indirection as
750 the leftmost operator ("p->a.b.d"), where instrumentation
751 is necessary. Or we may have an innocent "a.b.c"
752 expression that must not be instrumented. We need to
753 recurse all the way down the nesting structure to figure it
754 out: looking just at the outer node is not enough. */
756 int component_ref_only = (TREE_CODE (t) == COMPONENT_REF);
757 /* If we have a bitfield component reference, we must note the
758 innermost addressable object in ELT, from which we will
759 construct the byte-addressable bounds of the bitfield. */
760 tree elt = NULL_TREE;
761 int bitfield_ref_p = (TREE_CODE (t) == COMPONENT_REF
762 && DECL_BIT_FIELD_TYPE (TREE_OPERAND (t, 1)));
764 /* Iterate to the top of the ARRAY_REF/COMPONENT_REF
765 containment hierarchy to find the outermost VAR_DECL. */
766 var = TREE_OPERAND (t, 0);
769 if (bitfield_ref_p && elt == NULL_TREE
770 && (TREE_CODE (var) == ARRAY_REF
771 || TREE_CODE (var) == COMPONENT_REF))
774 if (TREE_CODE (var) == ARRAY_REF)
776 component_ref_only = 0;
777 var = TREE_OPERAND (var, 0);
779 else if (TREE_CODE (var) == COMPONENT_REF)
780 var = TREE_OPERAND (var, 0);
781 else if (INDIRECT_REF_P (var))
783 base = TREE_OPERAND (var, 0);
788 gcc_assert (TREE_CODE (var) == VAR_DECL
789 || TREE_CODE (var) == PARM_DECL
790 || TREE_CODE (var) == RESULT_DECL
791 || TREE_CODE (var) == STRING_CST);
792 /* Don't instrument this access if the underlying
793 variable is not "eligible". This test matches
794 those arrays that have only known-valid indexes,
795 and thus are not labeled TREE_ADDRESSABLE. */
796 if (! mf_decl_eligible_p (var) || component_ref_only)
800 base = build1 (ADDR_EXPR,
801 build_pointer_type (TREE_TYPE (var)), var);
807 /* Handle the case of ordinary non-indirection structure
808 accesses. These have only nested COMPONENT_REF nodes (no
809 INDIRECT_REF), but pass through the above filter loop.
810 Note that it's possible for such a struct variable to match
811 the eligible_p test because someone else might take its
814 /* We need special processing for bitfield components, because
815 their addresses cannot be taken. */
818 tree field = TREE_OPERAND (t, 1);
820 if (TREE_CODE (DECL_SIZE_UNIT (field)) == INTEGER_CST)
821 size = DECL_SIZE_UNIT (field);
824 elt = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (elt)),
826 addr = fold_convert (ptr_type_node, elt ? elt : base);
827 addr = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
828 addr, fold_convert (sizetype,
829 byte_position (field)));
832 addr = build1 (ADDR_EXPR, build_pointer_type (type), t);
834 limit = fold_build2 (MINUS_EXPR, mf_uintptr_type,
835 fold_build2 (PLUS_EXPR, mf_uintptr_type,
836 convert (mf_uintptr_type, addr),
843 addr = TREE_OPERAND (t, 0);
845 limit = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
846 fold_build2 (POINTER_PLUS_EXPR, ptr_type_node, base,
852 addr = tree_mem_ref_addr (ptr_type_node, t);
854 limit = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
855 fold_build2 (POINTER_PLUS_EXPR, ptr_type_node, base,
860 case ARRAY_RANGE_REF:
861 warning (0, "mudflap checking not yet implemented for ARRAY_RANGE_REF");
865 /* ??? merge with COMPONENT_REF code above? */
869 /* If we're not dereferencing something, then the access
871 if (TREE_CODE (TREE_OPERAND (t, 0)) != INDIRECT_REF)
874 bpu = bitsize_int (BITS_PER_UNIT);
875 ofs = convert (bitsizetype, TREE_OPERAND (t, 2));
876 rem = size_binop (TRUNC_MOD_EXPR, ofs, bpu);
877 ofs = fold_convert (sizetype, size_binop (TRUNC_DIV_EXPR, ofs, bpu));
879 size = convert (bitsizetype, TREE_OPERAND (t, 1));
880 size = size_binop (PLUS_EXPR, size, rem);
881 size = size_binop (CEIL_DIV_EXPR, size, bpu);
882 size = convert (sizetype, size);
884 addr = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
885 addr = convert (ptr_type_node, addr);
886 addr = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node, addr, ofs);
889 limit = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
890 fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
900 mf_build_check_statement_for (base, limit, iter, locus, dirflag);
904 mf_xform_derefs (void)
906 basic_block bb, next;
907 block_stmt_iterator i;
908 int saved_last_basic_block = last_basic_block;
910 bb = ENTRY_BLOCK_PTR ->next_bb;
914 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
916 tree s = bsi_stmt (i);
918 /* Only a few GIMPLE statements can reference memory. */
919 switch (TREE_CODE (s))
921 case GIMPLE_MODIFY_STMT:
922 mf_xform_derefs_1 (&i, &GIMPLE_STMT_OPERAND (s, 0),
923 EXPR_LOCUS (s), integer_one_node);
924 mf_xform_derefs_1 (&i, &GIMPLE_STMT_OPERAND (s, 1),
925 EXPR_LOCUS (s), integer_zero_node);
929 if (TREE_OPERAND (s, 0) != NULL_TREE)
931 if (TREE_CODE (TREE_OPERAND (s, 0)) == GIMPLE_MODIFY_STMT)
932 mf_xform_derefs_1 (&i, &GIMPLE_STMT_OPERAND
933 (TREE_OPERAND (s, 0), 1),
934 EXPR_LOCUS (s), integer_zero_node);
936 mf_xform_derefs_1 (&i, &TREE_OPERAND (s, 0), EXPR_LOCUS (s),
947 while (bb && bb->index <= saved_last_basic_block);
950 /* ------------------------------------------------------------------------ */
951 /* ADDR_EXPR transforms. Perform the declaration-related mudflap tree
952 transforms on the current function.
954 This is the first part of the mudflap instrumentation. It works on
955 high-level GIMPLE because after lowering, all variables are moved out
956 of their BIND_EXPR binding context, and we lose liveness information
957 for the declarations we wish to instrument. */
960 execute_mudflap_function_decls (void)
962 /* Don't instrument functions such as the synthetic constructor
963 built during mudflap_finish_file. */
964 if (mf_marked_p (current_function_decl) ||
965 DECL_ARTIFICIAL (current_function_decl))
968 push_gimplify_context ();
970 mf_xform_decls (DECL_SAVED_TREE (current_function_decl),
971 DECL_ARGUMENTS (current_function_decl));
973 pop_gimplify_context (NULL);
977 /* This struct is passed between mf_xform_decls to store state needed
978 during the traversal searching for objects that have their
980 struct mf_xform_decls_data
986 /* Synthesize a CALL_EXPR and a TRY_FINALLY_EXPR, for this chain of
987 _DECLs if appropriate. Arrange to call the __mf_register function
988 now, and the __mf_unregister function later for each. */
990 mx_register_decls (tree decl, tree *stmt_list)
992 tree finally_stmts = NULL_TREE;
993 tree_stmt_iterator initially_stmts = tsi_start (*stmt_list);
995 while (decl != NULL_TREE)
997 if (mf_decl_eligible_p (decl)
998 /* Not already processed. */
999 && ! mf_marked_p (decl)
1000 /* Automatic variable. */
1001 && ! DECL_EXTERNAL (decl)
1002 && ! TREE_STATIC (decl))
1004 tree size = NULL_TREE, variable_name;
1005 tree unregister_fncall, unregister_fncall_param;
1006 tree register_fncall, register_fncall_param;
1008 size = convert (size_type_node, TYPE_SIZE_UNIT (TREE_TYPE (decl)));
1011 unregister_fncall_param =
1012 convert (ptr_type_node,
1013 mf_mark (build1 (ADDR_EXPR,
1014 build_pointer_type (TREE_TYPE (decl)),
1016 /* __mf_unregister (&VARIABLE, sizeof (VARIABLE), __MF_TYPE_STACK) */
1017 unregister_fncall = build_call_expr (mf_unregister_fndecl, 3,
1018 unregister_fncall_param,
1020 build_int_cst (NULL_TREE, 3));
1023 variable_name = mf_varname_tree (decl);
1024 register_fncall_param =
1025 convert (ptr_type_node,
1026 mf_mark (build1 (ADDR_EXPR,
1027 build_pointer_type (TREE_TYPE (decl)),
1029 /* __mf_register (&VARIABLE, sizeof (VARIABLE), __MF_TYPE_STACK,
1031 register_fncall = build_call_expr (mf_register_fndecl, 4,
1032 register_fncall_param,
1034 build_int_cst (NULL_TREE, 3),
1038 /* Accumulate the two calls. */
1039 /* ??? Set EXPR_LOCATION. */
1040 gimplify_stmt (®ister_fncall);
1041 gimplify_stmt (&unregister_fncall);
1043 /* Add the __mf_register call at the current appending point. */
1044 if (tsi_end_p (initially_stmts))
1045 warning (0, "mudflap cannot track %qs in stub function",
1046 IDENTIFIER_POINTER (DECL_NAME (decl)));
1049 tsi_link_before (&initially_stmts, register_fncall,
1052 /* Accumulate the FINALLY piece. */
1053 append_to_statement_list (unregister_fncall, &finally_stmts);
1058 decl = TREE_CHAIN (decl);
1061 /* Actually, (initially_stmts!=NULL) <=> (finally_stmts!=NULL) */
1062 if (finally_stmts != NULL_TREE)
1064 tree t = build2 (TRY_FINALLY_EXPR, void_type_node,
1065 *stmt_list, finally_stmts);
1067 append_to_statement_list (t, stmt_list);
1072 /* Process every variable mentioned in BIND_EXPRs. */
1074 mx_xfn_xform_decls (tree *t, int *continue_p, void *data)
1076 struct mf_xform_decls_data* d = (struct mf_xform_decls_data*) data;
1078 if (*t == NULL_TREE || *t == error_mark_node)
1086 switch (TREE_CODE (*t))
1090 /* Process function parameters now (but only once). */
1091 mx_register_decls (d->param_decls, &BIND_EXPR_BODY (*t));
1092 d->param_decls = NULL_TREE;
1094 mx_register_decls (BIND_EXPR_VARS (*t), &BIND_EXPR_BODY (*t));
1105 /* Perform the object lifetime tracking mudflap transform on the given function
1106 tree. The tree is mutated in place, with possibly copied subtree nodes.
1108 For every auto variable declared, if its address is ever taken
1109 within the function, then supply its lifetime to the mudflap
1110 runtime with the __mf_register and __mf_unregister calls.
1114 mf_xform_decls (tree fnbody, tree fnparams)
1116 struct mf_xform_decls_data d;
1117 d.param_decls = fnparams;
1118 walk_tree_without_duplicates (&fnbody, mx_xfn_xform_decls, &d);
1122 /* ------------------------------------------------------------------------ */
1123 /* Externally visible mudflap functions. */
1126 /* Mark and return the given tree node to prevent further mudflap
1128 static GTY ((param_is (union tree_node))) htab_t marked_trees = NULL;
1135 if (marked_trees == NULL)
1136 marked_trees = htab_create_ggc (31, htab_hash_pointer, htab_eq_pointer,
1139 slot = htab_find_slot (marked_trees, t, INSERT);
1145 mf_marked_p (tree t)
1149 if (marked_trees == NULL)
1152 entry = htab_find (marked_trees, t);
1153 return (entry != NULL);
1156 /* Remember given node as a static of some kind: global data,
1157 function-scope static, or an anonymous constant. Its assembler
1160 /* A list of globals whose incomplete declarations we encountered.
1161 Instead of emitting the __mf_register call for them here, it's
1162 delayed until program finish time. If they're still incomplete by
1163 then, warnings are emitted. */
1165 static GTY (()) VEC(tree,gc) *deferred_static_decls;
1167 /* A list of statements for calling __mf_register() at startup time. */
1168 static GTY (()) tree enqueued_call_stmt_chain;
1171 mudflap_register_call (tree obj, tree object_size, tree varname)
1173 tree arg, call_stmt;
1175 arg = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (obj)), obj);
1176 arg = convert (ptr_type_node, arg);
1178 call_stmt = build_call_expr (mf_register_fndecl, 4,
1180 convert (size_type_node, object_size),
1181 /* __MF_TYPE_STATIC */
1182 build_int_cst (NULL_TREE, 4),
1185 append_to_statement_list (call_stmt, &enqueued_call_stmt_chain);
1189 mudflap_enqueue_decl (tree obj)
1191 if (mf_marked_p (obj))
1194 /* We don't need to process variable decls that are internally
1195 generated extern. If we did, we'd end up with warnings for them
1196 during mudflap_finish_file (). That would confuse the user,
1197 since the text would refer to variables that don't show up in the
1198 user's source code. */
1199 if (DECL_P (obj) && DECL_EXTERNAL (obj) && DECL_ARTIFICIAL (obj))
1202 VEC_safe_push (tree, gc, deferred_static_decls, obj);
1207 mudflap_enqueue_constant (tree obj)
1209 tree object_size, varname;
1211 if (mf_marked_p (obj))
1214 if (TREE_CODE (obj) == STRING_CST)
1215 object_size = build_int_cst (NULL_TREE, TREE_STRING_LENGTH (obj));
1217 object_size = size_in_bytes (TREE_TYPE (obj));
1219 if (TREE_CODE (obj) == STRING_CST)
1220 varname = mf_build_string ("string literal");
1222 varname = mf_build_string ("constant");
1224 mudflap_register_call (obj, object_size, varname);
1228 /* Emit any file-wide instrumentation. */
1230 mudflap_finish_file (void)
1232 tree ctor_statements = NULL_TREE;
1234 /* No need to continue when there were errors. */
1235 if (errorcount != 0 || sorrycount != 0)
1238 /* Insert a call to __mf_init. */
1240 tree call2_stmt = build_call_expr (mf_init_fndecl, 0);
1241 append_to_statement_list (call2_stmt, &ctor_statements);
1244 /* If appropriate, call __mf_set_options to pass along read-ignore mode. */
1245 if (flag_mudflap_ignore_reads)
1247 tree arg = mf_build_string ("-ignore-reads");
1248 tree call_stmt = build_call_expr (mf_set_options_fndecl, 1, arg);
1249 append_to_statement_list (call_stmt, &ctor_statements);
1252 /* Process all enqueued object decls. */
1253 if (deferred_static_decls)
1257 for (i = 0; VEC_iterate (tree, deferred_static_decls, i, obj); i++)
1259 gcc_assert (DECL_P (obj));
1261 if (mf_marked_p (obj))
1264 /* Omit registration for static unaddressed objects. NB:
1265 Perform registration for non-static objects regardless of
1266 TREE_USED or TREE_ADDRESSABLE, because they may be used
1267 from other compilation units. */
1268 if (! TREE_PUBLIC (obj) && ! TREE_ADDRESSABLE (obj))
1271 if (! COMPLETE_TYPE_P (TREE_TYPE (obj)))
1273 warning (0, "mudflap cannot track unknown size extern %qs",
1274 IDENTIFIER_POINTER (DECL_NAME (obj)));
1278 mudflap_register_call (obj,
1279 size_in_bytes (TREE_TYPE (obj)),
1280 mf_varname_tree (obj));
1283 VEC_truncate (tree, deferred_static_decls, 0);
1286 /* Append all the enqueued registration calls. */
1287 if (enqueued_call_stmt_chain)
1289 append_to_statement_list (enqueued_call_stmt_chain, &ctor_statements);
1290 enqueued_call_stmt_chain = NULL_TREE;
1293 cgraph_build_static_cdtor ('I', ctor_statements,
1294 MAX_RESERVED_INIT_PRIORITY-1);
1301 return flag_mudflap != 0;
1304 struct tree_opt_pass pass_mudflap_1 =
1306 "mudflap1", /* name */
1307 gate_mudflap, /* gate */
1308 execute_mudflap_function_decls, /* execute */
1311 0, /* static_pass_number */
1313 PROP_gimple_any, /* properties_required */
1314 0, /* properties_provided */
1315 0, /* properties_destroyed */
1316 0, /* todo_flags_start */
1317 TODO_dump_func, /* todo_flags_finish */
1321 struct tree_opt_pass pass_mudflap_2 =
1323 "mudflap2", /* name */
1324 gate_mudflap, /* gate */
1325 execute_mudflap_function_ops, /* execute */
1328 0, /* static_pass_number */
1330 PROP_gimple_leh, /* properties_required */
1331 0, /* properties_provided */
1332 0, /* properties_destroyed */
1333 0, /* todo_flags_start */
1334 TODO_verify_flow | TODO_verify_stmts
1335 | TODO_dump_func, /* todo_flags_finish */
1339 #include "gt-tree-mudflap.h"