1 /* Mudflap: narrow-pointer bounds-checking by tree rewriting.
2 Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008
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 3, 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 COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
26 #include "coretypes.h"
28 #include "hard-reg-set.h"
32 #include "basic-block.h"
35 #include "tree-inline.h"
36 #include "tree-gimple.h"
37 #include "tree-flow.h"
38 #include "tree-mudflap.h"
39 #include "tree-dump.h"
40 #include "tree-pass.h"
42 #include "diagnostic.h"
44 #include "langhooks.h"
49 /* Internal function decls */
53 #define flag_mudflap_threads (flag_mudflap == 2)
56 static tree mf_build_string (const char *string);
57 static tree mf_varname_tree (tree);
58 static tree mf_file_function_line_tree (location_t);
60 /* Indirection-related instrumentation. */
61 static void mf_decl_cache_locals (void);
62 static void mf_decl_clear_locals (void);
63 static void mf_xform_derefs (void);
64 static unsigned int execute_mudflap_function_ops (void);
66 /* Addressable variables instrumentation. */
67 static void mf_xform_decls (tree, tree);
68 static tree mx_xfn_xform_decls (tree *, int *, void *);
69 static void mx_register_decls (tree, tree *);
70 static unsigned int execute_mudflap_function_decls (void);
73 /* ------------------------------------------------------------------------ */
74 /* Some generally helpful functions for mudflap instrumentation. */
76 /* Build a reference to a literal string. */
78 mf_build_string (const char *string)
80 size_t len = strlen (string);
81 tree result = mf_mark (build_string (len + 1, string));
83 TREE_TYPE (result) = build_array_type
84 (char_type_node, build_index_type (build_int_cst (NULL_TREE, len)));
85 TREE_CONSTANT (result) = 1;
86 TREE_READONLY (result) = 1;
87 TREE_STATIC (result) = 1;
89 result = build1 (ADDR_EXPR, build_pointer_type (char_type_node), result);
91 return mf_mark (result);
94 /* Create a properly typed STRING_CST node that describes the given
95 declaration. It will be used as an argument for __mf_register().
96 Try to construct a helpful string, including file/function/variable
100 mf_varname_tree (tree decl)
102 static pretty_printer buf_rec;
103 static int initialized = 0;
104 pretty_printer *buf = & buf_rec;
105 const char *buf_contents;
112 pp_construct (buf, /* prefix */ NULL, /* line-width */ 0);
115 pp_clear_output_area (buf);
117 /* Add FILENAME[:LINENUMBER[:COLUMNNUMBER]]. */
119 expanded_location xloc = expand_location (DECL_SOURCE_LOCATION (decl));
120 const char *sourcefile;
121 unsigned sourceline = xloc.line;
122 unsigned sourcecolumn = 0;
123 sourcecolumn = xloc.column;
124 sourcefile = xloc.file;
125 if (sourcefile == NULL && current_function_decl != NULL_TREE)
126 sourcefile = DECL_SOURCE_FILE (current_function_decl);
127 if (sourcefile == NULL)
128 sourcefile = "<unknown file>";
130 pp_string (buf, sourcefile);
134 pp_string (buf, ":");
135 pp_decimal_int (buf, sourceline);
137 if (sourcecolumn != 0)
139 pp_string (buf, ":");
140 pp_decimal_int (buf, sourcecolumn);
145 if (current_function_decl != NULL_TREE)
148 pp_string (buf, " (");
150 const char *funcname = NULL;
151 if (DECL_NAME (current_function_decl))
152 funcname = lang_hooks.decl_printable_name (current_function_decl, 1);
153 if (funcname == NULL)
154 funcname = "anonymous fn";
156 pp_string (buf, funcname);
158 pp_string (buf, ") ");
161 pp_string (buf, " ");
163 /* Add <variable-declaration>, possibly demangled. */
165 const char *declname = NULL;
167 if (DECL_NAME (decl) != NULL)
169 if (strcmp ("GNU C++", lang_hooks.name) == 0)
171 /* The gcc/cp decl_printable_name hook doesn't do as good a job as
172 the libiberty demangler. */
173 declname = cplus_demangle (IDENTIFIER_POINTER (DECL_NAME (decl)),
174 DMGL_AUTO | DMGL_VERBOSE);
176 if (declname == NULL)
177 declname = lang_hooks.decl_printable_name (decl, 3);
179 if (declname == NULL)
180 declname = "<unnamed variable>";
182 pp_string (buf, declname);
185 /* Return the lot as a new STRING_CST. */
186 buf_contents = pp_base_formatted_text (buf);
187 result = mf_build_string (buf_contents);
188 pp_clear_output_area (buf);
194 /* And another friend, for producing a simpler message. */
197 mf_file_function_line_tree (location_t location)
199 expanded_location xloc = expand_location (location);
200 const char *file = NULL, *colon, *line, *op, *name, *cp;
201 char linecolbuf[30]; /* Enough for two decimal numbers plus a colon. */
205 /* Add FILENAME[:LINENUMBER[:COLUMNNUMBER]]. */
207 if (file == NULL && current_function_decl != NULL_TREE)
208 file = DECL_SOURCE_FILE (current_function_decl);
210 file = "<unknown file>";
215 sprintf (linecolbuf, "%d:%d", xloc.line, xloc.column);
217 sprintf (linecolbuf, "%d", xloc.line);
224 /* Add (FUNCTION). */
225 name = lang_hooks.decl_printable_name (current_function_decl, 1);
234 string = concat (file, colon, line, op, name, cp, NULL);
235 result = mf_build_string (string);
242 /* global tree nodes */
244 /* Global tree objects for global variables and functions exported by
245 mudflap runtime library. mf_init_extern_trees must be called
246 before using these. */
248 /* uintptr_t (usually "unsigned long") */
249 static GTY (()) tree mf_uintptr_type;
251 /* struct __mf_cache { uintptr_t low; uintptr_t high; }; */
252 static GTY (()) tree mf_cache_struct_type;
254 /* struct __mf_cache * const */
255 static GTY (()) tree mf_cache_structptr_type;
257 /* extern struct __mf_cache __mf_lookup_cache []; */
258 static GTY (()) tree mf_cache_array_decl;
260 /* extern unsigned char __mf_lc_shift; */
261 static GTY (()) tree mf_cache_shift_decl;
263 /* extern uintptr_t __mf_lc_mask; */
264 static GTY (()) tree mf_cache_mask_decl;
266 /* Their function-scope local shadows, used in single-threaded mode only. */
268 /* auto const unsigned char __mf_lc_shift_l; */
269 static GTY (()) tree mf_cache_shift_decl_l;
271 /* auto const uintptr_t __mf_lc_mask_l; */
272 static GTY (()) tree mf_cache_mask_decl_l;
274 /* extern void __mf_check (void *ptr, size_t sz, int type, const char *); */
275 static GTY (()) tree mf_check_fndecl;
277 /* extern void __mf_register (void *ptr, size_t sz, int type, const char *); */
278 static GTY (()) tree mf_register_fndecl;
280 /* extern void __mf_unregister (void *ptr, size_t sz, int type); */
281 static GTY (()) tree mf_unregister_fndecl;
283 /* extern void __mf_init (); */
284 static GTY (()) tree mf_init_fndecl;
286 /* extern int __mf_set_options (const char*); */
287 static GTY (()) tree mf_set_options_fndecl;
290 /* Helper for mudflap_init: construct a decl with the given category,
291 name, and type, mark it an external reference, and pushdecl it. */
293 mf_make_builtin (enum tree_code category, const char *name, tree type)
295 tree decl = mf_mark (build_decl (category, get_identifier (name), type));
296 TREE_PUBLIC (decl) = 1;
297 DECL_EXTERNAL (decl) = 1;
298 lang_hooks.decls.pushdecl (decl);
299 /* The decl was declared by the compiler. */
300 DECL_ARTIFICIAL (decl) = 1;
301 /* And we don't want debug info for it. */
302 DECL_IGNORED_P (decl) = 1;
306 /* Helper for mudflap_init: construct a tree corresponding to the type
307 struct __mf_cache { uintptr_t low; uintptr_t high; };
308 where uintptr_t is the FIELD_TYPE argument. */
310 mf_make_mf_cache_struct_type (tree field_type)
312 /* There is, abominably, no language-independent way to construct a
313 RECORD_TYPE. So we have to call the basic type construction
314 primitives by hand. */
315 tree fieldlo = build_decl (FIELD_DECL, get_identifier ("low"), field_type);
316 tree fieldhi = build_decl (FIELD_DECL, get_identifier ("high"), field_type);
318 tree struct_type = make_node (RECORD_TYPE);
319 DECL_CONTEXT (fieldlo) = struct_type;
320 DECL_CONTEXT (fieldhi) = struct_type;
321 TREE_CHAIN (fieldlo) = fieldhi;
322 TYPE_FIELDS (struct_type) = fieldlo;
323 TYPE_NAME (struct_type) = get_identifier ("__mf_cache");
324 layout_type (struct_type);
329 #define build_function_type_0(rtype) \
330 build_function_type (rtype, void_list_node)
331 #define build_function_type_1(rtype, arg1) \
332 build_function_type (rtype, tree_cons (0, arg1, void_list_node))
333 #define build_function_type_3(rtype, arg1, arg2, arg3) \
334 build_function_type (rtype, \
335 tree_cons (0, arg1, \
336 tree_cons (0, arg2, \
337 tree_cons (0, arg3, \
339 #define build_function_type_4(rtype, arg1, arg2, arg3, arg4) \
340 build_function_type (rtype, \
341 tree_cons (0, arg1, \
342 tree_cons (0, arg2, \
343 tree_cons (0, arg3, \
344 tree_cons (0, arg4, \
347 /* Initialize the global tree nodes that correspond to mf-runtime.h
352 static bool done = false;
353 tree mf_const_string_type;
354 tree mf_cache_array_type;
355 tree mf_check_register_fntype;
356 tree mf_unregister_fntype;
358 tree mf_set_options_fntype;
364 mf_uintptr_type = lang_hooks.types.type_for_mode (ptr_mode,
367 = build_pointer_type (build_qualified_type
368 (char_type_node, TYPE_QUAL_CONST));
370 mf_cache_struct_type = mf_make_mf_cache_struct_type (mf_uintptr_type);
371 mf_cache_structptr_type = build_pointer_type (mf_cache_struct_type);
372 mf_cache_array_type = build_array_type (mf_cache_struct_type, 0);
373 mf_check_register_fntype =
374 build_function_type_4 (void_type_node, ptr_type_node, size_type_node,
375 integer_type_node, mf_const_string_type);
376 mf_unregister_fntype =
377 build_function_type_3 (void_type_node, ptr_type_node, size_type_node,
380 build_function_type_0 (void_type_node);
381 mf_set_options_fntype =
382 build_function_type_1 (integer_type_node, mf_const_string_type);
384 mf_cache_array_decl = mf_make_builtin (VAR_DECL, "__mf_lookup_cache",
385 mf_cache_array_type);
386 mf_cache_shift_decl = mf_make_builtin (VAR_DECL, "__mf_lc_shift",
387 unsigned_char_type_node);
388 mf_cache_mask_decl = mf_make_builtin (VAR_DECL, "__mf_lc_mask",
390 /* Don't process these in mudflap_enqueue_decl, should they come by
391 there for some reason. */
392 mf_mark (mf_cache_array_decl);
393 mf_mark (mf_cache_shift_decl);
394 mf_mark (mf_cache_mask_decl);
395 mf_check_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_check",
396 mf_check_register_fntype);
397 mf_register_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_register",
398 mf_check_register_fntype);
399 mf_unregister_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_unregister",
400 mf_unregister_fntype);
401 mf_init_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_init",
403 mf_set_options_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_set_options",
404 mf_set_options_fntype);
406 #undef build_function_type_4
407 #undef build_function_type_3
408 #undef build_function_type_1
409 #undef build_function_type_0
412 /* ------------------------------------------------------------------------ */
413 /* Memory reference transforms. Perform the mudflap indirection-related
414 tree transforms on the current function.
416 This is the second part of the mudflap instrumentation. It works on
417 low-level GIMPLE using the CFG, because we want to run this pass after
418 tree optimizations have been performed, but we have to preserve the CFG
419 for expansion from trees to RTL. */
422 execute_mudflap_function_ops (void)
424 struct gimplify_ctx gctx;
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 (&gctx);
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 (OPT_Wmudflap,
862 "mudflap checking not yet implemented for ARRAY_RANGE_REF");
866 /* ??? merge with COMPONENT_REF code above? */
870 /* If we're not dereferencing something, then the access
872 if (TREE_CODE (TREE_OPERAND (t, 0)) != INDIRECT_REF)
875 bpu = bitsize_int (BITS_PER_UNIT);
876 ofs = convert (bitsizetype, TREE_OPERAND (t, 2));
877 rem = size_binop (TRUNC_MOD_EXPR, ofs, bpu);
878 ofs = fold_convert (sizetype, size_binop (TRUNC_DIV_EXPR, ofs, bpu));
880 size = convert (bitsizetype, TREE_OPERAND (t, 1));
881 size = size_binop (PLUS_EXPR, size, rem);
882 size = size_binop (CEIL_DIV_EXPR, size, bpu);
883 size = convert (sizetype, size);
885 addr = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
886 addr = convert (ptr_type_node, addr);
887 addr = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node, addr, ofs);
890 limit = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
891 fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
901 mf_build_check_statement_for (base, limit, iter, locus, dirflag);
905 mf_xform_derefs (void)
907 basic_block bb, next;
908 block_stmt_iterator i;
909 int saved_last_basic_block = last_basic_block;
911 bb = ENTRY_BLOCK_PTR ->next_bb;
915 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
917 tree s = bsi_stmt (i);
919 /* Only a few GIMPLE statements can reference memory. */
920 switch (TREE_CODE (s))
922 case GIMPLE_MODIFY_STMT:
923 mf_xform_derefs_1 (&i, &GIMPLE_STMT_OPERAND (s, 0),
924 EXPR_LOCUS (s), integer_one_node);
925 mf_xform_derefs_1 (&i, &GIMPLE_STMT_OPERAND (s, 1),
926 EXPR_LOCUS (s), integer_zero_node);
930 if (TREE_OPERAND (s, 0) != NULL_TREE)
932 if (TREE_CODE (TREE_OPERAND (s, 0)) == GIMPLE_MODIFY_STMT)
933 mf_xform_derefs_1 (&i, &GIMPLE_STMT_OPERAND
934 (TREE_OPERAND (s, 0), 1),
935 EXPR_LOCUS (s), integer_zero_node);
937 mf_xform_derefs_1 (&i, &TREE_OPERAND (s, 0), EXPR_LOCUS (s),
948 while (bb && bb->index <= saved_last_basic_block);
951 /* ------------------------------------------------------------------------ */
952 /* ADDR_EXPR transforms. Perform the declaration-related mudflap tree
953 transforms on the current function.
955 This is the first part of the mudflap instrumentation. It works on
956 high-level GIMPLE because after lowering, all variables are moved out
957 of their BIND_EXPR binding context, and we lose liveness information
958 for the declarations we wish to instrument. */
961 execute_mudflap_function_decls (void)
963 struct gimplify_ctx gctx;
965 /* Don't instrument functions such as the synthetic constructor
966 built during mudflap_finish_file. */
967 if (mf_marked_p (current_function_decl) ||
968 DECL_ARTIFICIAL (current_function_decl))
971 push_gimplify_context (&gctx);
973 mf_xform_decls (DECL_SAVED_TREE (current_function_decl),
974 DECL_ARGUMENTS (current_function_decl));
976 pop_gimplify_context (NULL);
980 /* This struct is passed between mf_xform_decls to store state needed
981 during the traversal searching for objects that have their
983 struct mf_xform_decls_data
989 /* Synthesize a CALL_EXPR and a TRY_FINALLY_EXPR, for this chain of
990 _DECLs if appropriate. Arrange to call the __mf_register function
991 now, and the __mf_unregister function later for each. */
993 mx_register_decls (tree decl, tree *stmt_list)
995 tree finally_stmts = NULL_TREE;
996 tree_stmt_iterator initially_stmts = tsi_start (*stmt_list);
998 while (decl != NULL_TREE)
1000 if (mf_decl_eligible_p (decl)
1001 /* Not already processed. */
1002 && ! mf_marked_p (decl)
1003 /* Automatic variable. */
1004 && ! DECL_EXTERNAL (decl)
1005 && ! TREE_STATIC (decl))
1007 tree size = NULL_TREE, variable_name;
1008 tree unregister_fncall, unregister_fncall_param;
1009 tree register_fncall, register_fncall_param;
1011 size = convert (size_type_node, TYPE_SIZE_UNIT (TREE_TYPE (decl)));
1014 unregister_fncall_param =
1015 convert (ptr_type_node,
1016 mf_mark (build1 (ADDR_EXPR,
1017 build_pointer_type (TREE_TYPE (decl)),
1019 /* __mf_unregister (&VARIABLE, sizeof (VARIABLE), __MF_TYPE_STACK) */
1020 unregister_fncall = build_call_expr (mf_unregister_fndecl, 3,
1021 unregister_fncall_param,
1023 build_int_cst (NULL_TREE, 3));
1026 variable_name = mf_varname_tree (decl);
1027 register_fncall_param =
1028 convert (ptr_type_node,
1029 mf_mark (build1 (ADDR_EXPR,
1030 build_pointer_type (TREE_TYPE (decl)),
1032 /* __mf_register (&VARIABLE, sizeof (VARIABLE), __MF_TYPE_STACK,
1034 register_fncall = build_call_expr (mf_register_fndecl, 4,
1035 register_fncall_param,
1037 build_int_cst (NULL_TREE, 3),
1041 /* Accumulate the two calls. */
1042 /* ??? Set EXPR_LOCATION. */
1043 gimplify_stmt (®ister_fncall);
1044 gimplify_stmt (&unregister_fncall);
1046 /* Add the __mf_register call at the current appending point. */
1047 if (tsi_end_p (initially_stmts))
1049 if (!DECL_ARTIFICIAL (decl))
1050 warning (OPT_Wmudflap,
1051 "mudflap cannot track %qs in stub function",
1052 IDENTIFIER_POINTER (DECL_NAME (decl)));
1056 tsi_link_before (&initially_stmts, register_fncall,
1059 /* Accumulate the FINALLY piece. */
1060 append_to_statement_list (unregister_fncall, &finally_stmts);
1065 decl = TREE_CHAIN (decl);
1068 /* Actually, (initially_stmts!=NULL) <=> (finally_stmts!=NULL) */
1069 if (finally_stmts != NULL_TREE)
1071 tree t = build2 (TRY_FINALLY_EXPR, void_type_node,
1072 *stmt_list, finally_stmts);
1074 append_to_statement_list (t, stmt_list);
1079 /* Process every variable mentioned in BIND_EXPRs. */
1081 mx_xfn_xform_decls (tree *t, int *continue_p, void *data)
1083 struct mf_xform_decls_data* d = (struct mf_xform_decls_data*) data;
1085 if (*t == NULL_TREE || *t == error_mark_node)
1093 switch (TREE_CODE (*t))
1097 /* Process function parameters now (but only once). */
1098 mx_register_decls (d->param_decls, &BIND_EXPR_BODY (*t));
1099 d->param_decls = NULL_TREE;
1101 mx_register_decls (BIND_EXPR_VARS (*t), &BIND_EXPR_BODY (*t));
1112 /* Perform the object lifetime tracking mudflap transform on the given function
1113 tree. The tree is mutated in place, with possibly copied subtree nodes.
1115 For every auto variable declared, if its address is ever taken
1116 within the function, then supply its lifetime to the mudflap
1117 runtime with the __mf_register and __mf_unregister calls.
1121 mf_xform_decls (tree fnbody, tree fnparams)
1123 struct mf_xform_decls_data d;
1124 d.param_decls = fnparams;
1125 walk_tree_without_duplicates (&fnbody, mx_xfn_xform_decls, &d);
1129 /* ------------------------------------------------------------------------ */
1130 /* Externally visible mudflap functions. */
1133 /* Mark and return the given tree node to prevent further mudflap
1135 static GTY ((param_is (union tree_node))) htab_t marked_trees = NULL;
1142 if (marked_trees == NULL)
1143 marked_trees = htab_create_ggc (31, htab_hash_pointer, htab_eq_pointer,
1146 slot = htab_find_slot (marked_trees, t, INSERT);
1152 mf_marked_p (tree t)
1156 if (marked_trees == NULL)
1159 entry = htab_find (marked_trees, t);
1160 return (entry != NULL);
1163 /* Remember given node as a static of some kind: global data,
1164 function-scope static, or an anonymous constant. Its assembler
1167 /* A list of globals whose incomplete declarations we encountered.
1168 Instead of emitting the __mf_register call for them here, it's
1169 delayed until program finish time. If they're still incomplete by
1170 then, warnings are emitted. */
1172 static GTY (()) VEC(tree,gc) *deferred_static_decls;
1174 /* A list of statements for calling __mf_register() at startup time. */
1175 static GTY (()) tree enqueued_call_stmt_chain;
1178 mudflap_register_call (tree obj, tree object_size, tree varname)
1180 tree arg, call_stmt;
1182 arg = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (obj)), obj);
1183 arg = convert (ptr_type_node, arg);
1185 call_stmt = build_call_expr (mf_register_fndecl, 4,
1187 convert (size_type_node, object_size),
1188 /* __MF_TYPE_STATIC */
1189 build_int_cst (NULL_TREE, 4),
1192 append_to_statement_list (call_stmt, &enqueued_call_stmt_chain);
1196 mudflap_enqueue_decl (tree obj)
1198 if (mf_marked_p (obj))
1201 /* We don't need to process variable decls that are internally
1202 generated extern. If we did, we'd end up with warnings for them
1203 during mudflap_finish_file (). That would confuse the user,
1204 since the text would refer to variables that don't show up in the
1205 user's source code. */
1206 if (DECL_P (obj) && DECL_EXTERNAL (obj) && DECL_ARTIFICIAL (obj))
1209 VEC_safe_push (tree, gc, deferred_static_decls, obj);
1214 mudflap_enqueue_constant (tree obj)
1216 tree object_size, varname;
1218 if (mf_marked_p (obj))
1221 if (TREE_CODE (obj) == STRING_CST)
1222 object_size = build_int_cst (NULL_TREE, TREE_STRING_LENGTH (obj));
1224 object_size = size_in_bytes (TREE_TYPE (obj));
1226 if (TREE_CODE (obj) == STRING_CST)
1227 varname = mf_build_string ("string literal");
1229 varname = mf_build_string ("constant");
1231 mudflap_register_call (obj, object_size, varname);
1235 /* Emit any file-wide instrumentation. */
1237 mudflap_finish_file (void)
1239 tree ctor_statements = NULL_TREE;
1241 /* No need to continue when there were errors. */
1242 if (errorcount != 0 || sorrycount != 0)
1245 /* Insert a call to __mf_init. */
1247 tree call2_stmt = build_call_expr (mf_init_fndecl, 0);
1248 append_to_statement_list (call2_stmt, &ctor_statements);
1251 /* If appropriate, call __mf_set_options to pass along read-ignore mode. */
1252 if (flag_mudflap_ignore_reads)
1254 tree arg = mf_build_string ("-ignore-reads");
1255 tree call_stmt = build_call_expr (mf_set_options_fndecl, 1, arg);
1256 append_to_statement_list (call_stmt, &ctor_statements);
1259 /* Process all enqueued object decls. */
1260 if (deferred_static_decls)
1264 for (i = 0; VEC_iterate (tree, deferred_static_decls, i, obj); i++)
1266 gcc_assert (DECL_P (obj));
1268 if (mf_marked_p (obj))
1271 /* Omit registration for static unaddressed objects. NB:
1272 Perform registration for non-static objects regardless of
1273 TREE_USED or TREE_ADDRESSABLE, because they may be used
1274 from other compilation units. */
1275 if (! TREE_PUBLIC (obj) && ! TREE_ADDRESSABLE (obj))
1278 if (! COMPLETE_TYPE_P (TREE_TYPE (obj)))
1280 warning (OPT_Wmudflap,
1281 "mudflap cannot track unknown size extern %qs",
1282 IDENTIFIER_POINTER (DECL_NAME (obj)));
1286 mudflap_register_call (obj,
1287 size_in_bytes (TREE_TYPE (obj)),
1288 mf_varname_tree (obj));
1291 VEC_truncate (tree, deferred_static_decls, 0);
1294 /* Append all the enqueued registration calls. */
1295 if (enqueued_call_stmt_chain)
1297 append_to_statement_list (enqueued_call_stmt_chain, &ctor_statements);
1298 enqueued_call_stmt_chain = NULL_TREE;
1301 cgraph_build_static_cdtor ('I', ctor_statements,
1302 MAX_RESERVED_INIT_PRIORITY-1);
1309 return flag_mudflap != 0;
1312 struct gimple_opt_pass pass_mudflap_1 =
1316 "mudflap1", /* name */
1317 gate_mudflap, /* gate */
1318 execute_mudflap_function_decls, /* execute */
1321 0, /* static_pass_number */
1323 PROP_gimple_any, /* properties_required */
1324 0, /* properties_provided */
1325 0, /* properties_destroyed */
1326 0, /* todo_flags_start */
1327 TODO_dump_func /* todo_flags_finish */
1331 struct gimple_opt_pass pass_mudflap_2 =
1335 "mudflap2", /* name */
1336 gate_mudflap, /* gate */
1337 execute_mudflap_function_ops, /* execute */
1340 0, /* static_pass_number */
1342 PROP_gimple_leh, /* properties_required */
1343 0, /* properties_provided */
1344 0, /* properties_destroyed */
1345 0, /* todo_flags_start */
1346 TODO_verify_flow | TODO_verify_stmts
1347 | TODO_dump_func /* todo_flags_finish */
1351 #include "gt-tree-mudflap.h"