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"
37 #include "tree-iterator.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"
51 /* Internal function decls */
55 #define flag_mudflap_threads (flag_mudflap == 2)
58 static tree mf_build_string (const char *string);
59 static tree mf_varname_tree (tree);
60 static tree mf_file_function_line_tree (location_t);
62 /* Indirection-related instrumentation. */
63 static void mf_decl_cache_locals (void);
64 static void mf_decl_clear_locals (void);
65 static void mf_xform_derefs (void);
66 static unsigned int execute_mudflap_function_ops (void);
68 /* Addressable variables instrumentation. */
69 static void mf_xform_decls (gimple_seq, tree);
70 static tree mx_xfn_xform_decls (gimple_stmt_iterator *, bool *,
71 struct walk_stmt_info *);
72 static gimple_seq mx_register_decls (tree, gimple_seq, location_t);
73 static unsigned int execute_mudflap_function_decls (void);
76 /* ------------------------------------------------------------------------ */
77 /* Some generally helpful functions for mudflap instrumentation. */
79 /* Build a reference to a literal string. */
81 mf_build_string (const char *string)
83 size_t len = strlen (string);
84 tree result = mf_mark (build_string (len + 1, string));
86 TREE_TYPE (result) = build_array_type
87 (char_type_node, build_index_type (build_int_cst (NULL_TREE, len)));
88 TREE_CONSTANT (result) = 1;
89 TREE_READONLY (result) = 1;
90 TREE_STATIC (result) = 1;
92 result = build1 (ADDR_EXPR, build_pointer_type (char_type_node), result);
94 return mf_mark (result);
97 /* Create a properly typed STRING_CST node that describes the given
98 declaration. It will be used as an argument for __mf_register().
99 Try to construct a helpful string, including file/function/variable
103 mf_varname_tree (tree decl)
105 static pretty_printer buf_rec;
106 static int initialized = 0;
107 pretty_printer *buf = & buf_rec;
108 const char *buf_contents;
115 pp_construct (buf, /* prefix */ NULL, /* line-width */ 0);
118 pp_clear_output_area (buf);
120 /* Add FILENAME[:LINENUMBER[:COLUMNNUMBER]]. */
122 expanded_location xloc = expand_location (DECL_SOURCE_LOCATION (decl));
123 const char *sourcefile;
124 unsigned sourceline = xloc.line;
125 unsigned sourcecolumn = 0;
126 sourcecolumn = xloc.column;
127 sourcefile = xloc.file;
128 if (sourcefile == NULL && current_function_decl != NULL_TREE)
129 sourcefile = DECL_SOURCE_FILE (current_function_decl);
130 if (sourcefile == NULL)
131 sourcefile = "<unknown file>";
133 pp_string (buf, sourcefile);
137 pp_string (buf, ":");
138 pp_decimal_int (buf, sourceline);
140 if (sourcecolumn != 0)
142 pp_string (buf, ":");
143 pp_decimal_int (buf, sourcecolumn);
148 if (current_function_decl != NULL_TREE)
151 pp_string (buf, " (");
153 const char *funcname = NULL;
154 if (DECL_NAME (current_function_decl))
155 funcname = lang_hooks.decl_printable_name (current_function_decl, 1);
156 if (funcname == NULL)
157 funcname = "anonymous fn";
159 pp_string (buf, funcname);
161 pp_string (buf, ") ");
164 pp_string (buf, " ");
166 /* Add <variable-declaration>, possibly demangled. */
168 const char *declname = NULL;
170 if (DECL_NAME (decl) != NULL)
172 if (strcmp ("GNU C++", lang_hooks.name) == 0)
174 /* The gcc/cp decl_printable_name hook doesn't do as good a job as
175 the libiberty demangler. */
176 declname = cplus_demangle (IDENTIFIER_POINTER (DECL_NAME (decl)),
177 DMGL_AUTO | DMGL_VERBOSE);
179 if (declname == NULL)
180 declname = lang_hooks.decl_printable_name (decl, 3);
182 if (declname == NULL)
183 declname = "<unnamed variable>";
185 pp_string (buf, declname);
188 /* Return the lot as a new STRING_CST. */
189 buf_contents = pp_base_formatted_text (buf);
190 result = mf_build_string (buf_contents);
191 pp_clear_output_area (buf);
197 /* And another friend, for producing a simpler message. */
200 mf_file_function_line_tree (location_t location)
202 expanded_location xloc = expand_location (location);
203 const char *file = NULL, *colon, *line, *op, *name, *cp;
204 char linecolbuf[30]; /* Enough for two decimal numbers plus a colon. */
208 /* Add FILENAME[:LINENUMBER[:COLUMNNUMBER]]. */
210 if (file == NULL && current_function_decl != NULL_TREE)
211 file = DECL_SOURCE_FILE (current_function_decl);
213 file = "<unknown file>";
218 sprintf (linecolbuf, "%d:%d", xloc.line, xloc.column);
220 sprintf (linecolbuf, "%d", xloc.line);
227 /* Add (FUNCTION). */
228 name = lang_hooks.decl_printable_name (current_function_decl, 1);
237 string = concat (file, colon, line, op, name, cp, NULL);
238 result = mf_build_string (string);
245 /* global tree nodes */
247 /* Global tree objects for global variables and functions exported by
248 mudflap runtime library. mf_init_extern_trees must be called
249 before using these. */
251 /* uintptr_t (usually "unsigned long") */
252 static GTY (()) tree mf_uintptr_type;
254 /* struct __mf_cache { uintptr_t low; uintptr_t high; }; */
255 static GTY (()) tree mf_cache_struct_type;
257 /* struct __mf_cache * const */
258 static GTY (()) tree mf_cache_structptr_type;
260 /* extern struct __mf_cache __mf_lookup_cache []; */
261 static GTY (()) tree mf_cache_array_decl;
263 /* extern unsigned char __mf_lc_shift; */
264 static GTY (()) tree mf_cache_shift_decl;
266 /* extern uintptr_t __mf_lc_mask; */
267 static GTY (()) tree mf_cache_mask_decl;
269 /* Their function-scope local shadows, used in single-threaded mode only. */
271 /* auto const unsigned char __mf_lc_shift_l; */
272 static GTY (()) tree mf_cache_shift_decl_l;
274 /* auto const uintptr_t __mf_lc_mask_l; */
275 static GTY (()) tree mf_cache_mask_decl_l;
277 /* extern void __mf_check (void *ptr, size_t sz, int type, const char *); */
278 static GTY (()) tree mf_check_fndecl;
280 /* extern void __mf_register (void *ptr, size_t sz, int type, const char *); */
281 static GTY (()) tree mf_register_fndecl;
283 /* extern void __mf_unregister (void *ptr, size_t sz, int type); */
284 static GTY (()) tree mf_unregister_fndecl;
286 /* extern void __mf_init (); */
287 static GTY (()) tree mf_init_fndecl;
289 /* extern int __mf_set_options (const char*); */
290 static GTY (()) tree mf_set_options_fndecl;
293 /* Helper for mudflap_init: construct a decl with the given category,
294 name, and type, mark it an external reference, and pushdecl it. */
296 mf_make_builtin (enum tree_code category, const char *name, tree type)
298 tree decl = mf_mark (build_decl (category, get_identifier (name), type));
299 TREE_PUBLIC (decl) = 1;
300 DECL_EXTERNAL (decl) = 1;
301 lang_hooks.decls.pushdecl (decl);
302 /* The decl was declared by the compiler. */
303 DECL_ARTIFICIAL (decl) = 1;
304 /* And we don't want debug info for it. */
305 DECL_IGNORED_P (decl) = 1;
309 /* Helper for mudflap_init: construct a tree corresponding to the type
310 struct __mf_cache { uintptr_t low; uintptr_t high; };
311 where uintptr_t is the FIELD_TYPE argument. */
313 mf_make_mf_cache_struct_type (tree field_type)
315 /* There is, abominably, no language-independent way to construct a
316 RECORD_TYPE. So we have to call the basic type construction
317 primitives by hand. */
318 tree fieldlo = build_decl (FIELD_DECL, get_identifier ("low"), field_type);
319 tree fieldhi = build_decl (FIELD_DECL, get_identifier ("high"), field_type);
321 tree struct_type = make_node (RECORD_TYPE);
322 DECL_CONTEXT (fieldlo) = struct_type;
323 DECL_CONTEXT (fieldhi) = struct_type;
324 TREE_CHAIN (fieldlo) = fieldhi;
325 TYPE_FIELDS (struct_type) = fieldlo;
326 TYPE_NAME (struct_type) = get_identifier ("__mf_cache");
327 layout_type (struct_type);
332 #define build_function_type_0(rtype) \
333 build_function_type (rtype, void_list_node)
334 #define build_function_type_1(rtype, arg1) \
335 build_function_type (rtype, tree_cons (0, arg1, void_list_node))
336 #define build_function_type_3(rtype, arg1, arg2, arg3) \
337 build_function_type (rtype, \
338 tree_cons (0, arg1, \
339 tree_cons (0, arg2, \
340 tree_cons (0, arg3, \
342 #define build_function_type_4(rtype, arg1, arg2, arg3, arg4) \
343 build_function_type (rtype, \
344 tree_cons (0, arg1, \
345 tree_cons (0, arg2, \
346 tree_cons (0, arg3, \
347 tree_cons (0, arg4, \
350 /* Initialize the global tree nodes that correspond to mf-runtime.h
355 static bool done = false;
356 tree mf_const_string_type;
357 tree mf_cache_array_type;
358 tree mf_check_register_fntype;
359 tree mf_unregister_fntype;
361 tree mf_set_options_fntype;
367 mf_uintptr_type = lang_hooks.types.type_for_mode (ptr_mode,
370 = build_pointer_type (build_qualified_type
371 (char_type_node, TYPE_QUAL_CONST));
373 mf_cache_struct_type = mf_make_mf_cache_struct_type (mf_uintptr_type);
374 mf_cache_structptr_type = build_pointer_type (mf_cache_struct_type);
375 mf_cache_array_type = build_array_type (mf_cache_struct_type, 0);
376 mf_check_register_fntype =
377 build_function_type_4 (void_type_node, ptr_type_node, size_type_node,
378 integer_type_node, mf_const_string_type);
379 mf_unregister_fntype =
380 build_function_type_3 (void_type_node, ptr_type_node, size_type_node,
383 build_function_type_0 (void_type_node);
384 mf_set_options_fntype =
385 build_function_type_1 (integer_type_node, mf_const_string_type);
387 mf_cache_array_decl = mf_make_builtin (VAR_DECL, "__mf_lookup_cache",
388 mf_cache_array_type);
389 mf_cache_shift_decl = mf_make_builtin (VAR_DECL, "__mf_lc_shift",
390 unsigned_char_type_node);
391 mf_cache_mask_decl = mf_make_builtin (VAR_DECL, "__mf_lc_mask",
393 /* Don't process these in mudflap_enqueue_decl, should they come by
394 there for some reason. */
395 mf_mark (mf_cache_array_decl);
396 mf_mark (mf_cache_shift_decl);
397 mf_mark (mf_cache_mask_decl);
398 mf_check_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_check",
399 mf_check_register_fntype);
400 mf_register_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_register",
401 mf_check_register_fntype);
402 mf_unregister_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_unregister",
403 mf_unregister_fntype);
404 mf_init_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_init",
406 mf_set_options_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_set_options",
407 mf_set_options_fntype);
409 #undef build_function_type_4
410 #undef build_function_type_3
411 #undef build_function_type_1
412 #undef build_function_type_0
415 /* ------------------------------------------------------------------------ */
416 /* Memory reference transforms. Perform the mudflap indirection-related
417 tree transforms on the current function.
419 This is the second part of the mudflap instrumentation. It works on
420 low-level GIMPLE using the CFG, because we want to run this pass after
421 tree optimizations have been performed, but we have to preserve the CFG
422 for expansion from trees to RTL. */
425 execute_mudflap_function_ops (void)
427 struct gimplify_ctx gctx;
429 /* Don't instrument functions such as the synthetic constructor
430 built during mudflap_finish_file. */
431 if (mf_marked_p (current_function_decl) ||
432 DECL_ARTIFICIAL (current_function_decl))
435 push_gimplify_context (&gctx);
437 /* In multithreaded mode, don't cache the lookup cache parameters. */
438 if (! flag_mudflap_threads)
439 mf_decl_cache_locals ();
443 if (! flag_mudflap_threads)
444 mf_decl_clear_locals ();
446 pop_gimplify_context (NULL);
450 /* Create and initialize local shadow variables for the lookup cache
451 globals. Put their decls in the *_l globals for use by
452 mf_build_check_statement_for. */
455 mf_decl_cache_locals (void)
458 gimple_seq seq = gimple_seq_alloc ();
460 /* Build the cache vars. */
461 mf_cache_shift_decl_l
462 = mf_mark (create_tmp_var (TREE_TYPE (mf_cache_shift_decl),
463 "__mf_lookup_shift_l"));
466 = mf_mark (create_tmp_var (TREE_TYPE (mf_cache_mask_decl),
467 "__mf_lookup_mask_l"));
469 /* Build initialization nodes for the cache vars. We just load the
470 globals into the cache variables. */
471 g = gimple_build_assign (mf_cache_shift_decl_l, mf_cache_shift_decl);
472 gimple_set_location (g, DECL_SOURCE_LOCATION (current_function_decl));
473 gimple_seq_add_stmt (&seq, g);
475 g = gimple_build_assign (mf_cache_mask_decl_l, mf_cache_mask_decl);
476 gimple_set_location (g, DECL_SOURCE_LOCATION (current_function_decl));
477 gimple_seq_add_stmt (&seq, g);
479 insert_edge_copies_seq (seq, ENTRY_BLOCK_PTR);
481 gsi_commit_edge_inserts ();
486 mf_decl_clear_locals (void)
488 /* Unset local shadows. */
489 mf_cache_shift_decl_l = NULL_TREE;
490 mf_cache_mask_decl_l = NULL_TREE;
494 mf_build_check_statement_for (tree base, tree limit,
495 gimple_stmt_iterator *instr_gsi,
496 location_t location, tree dirflag)
498 gimple_stmt_iterator gsi;
499 basic_block cond_bb, then_bb, join_bb;
506 gimple_seq seq, stmts;
508 /* We first need to split the current basic block, and start altering
509 the CFG. This allows us to insert the statements we're about to
510 construct into the right basic blocks. */
512 cond_bb = gimple_bb (gsi_stmt (*instr_gsi));
515 if (! gsi_end_p (gsi))
516 e = split_block (cond_bb, gsi_stmt (gsi));
518 e = split_block_after_labels (cond_bb);
522 /* A recap at this point: join_bb is the basic block at whose head
523 is the gimple statement for which this check expression is being
524 built. cond_bb is the (possibly new, synthetic) basic block the
525 end of which will contain the cache-lookup code, and a
526 conditional that jumps to the cache-miss code or, much more
527 likely, over to join_bb. */
529 /* Create the bb that contains the cache-miss fallback block (mf_check). */
530 then_bb = create_empty_bb (cond_bb);
531 make_edge (cond_bb, then_bb, EDGE_TRUE_VALUE);
532 make_single_succ_edge (then_bb, join_bb, EDGE_FALLTHRU);
534 /* Mark the pseudo-fallthrough edge from cond_bb to join_bb. */
535 e = find_edge (cond_bb, join_bb);
536 e->flags = EDGE_FALSE_VALUE;
537 e->count = cond_bb->count;
538 e->probability = REG_BR_PROB_BASE;
540 /* Update dominance info. Note that bb_join's data was
541 updated by split_block. */
542 if (dom_info_available_p (CDI_DOMINATORS))
544 set_immediate_dominator (CDI_DOMINATORS, then_bb, cond_bb);
545 set_immediate_dominator (CDI_DOMINATORS, join_bb, cond_bb);
548 /* Build our local variables. */
549 mf_elem = create_tmp_var (mf_cache_structptr_type, "__mf_elem");
550 mf_base = create_tmp_var (mf_uintptr_type, "__mf_base");
551 mf_limit = create_tmp_var (mf_uintptr_type, "__mf_limit");
553 /* Build: __mf_base = (uintptr_t) <base address expression>. */
554 seq = gimple_seq_alloc ();
555 t = fold_convert (mf_uintptr_type, unshare_expr (base));
556 t = force_gimple_operand (t, &stmts, false, NULL_TREE);
557 gimple_seq_add_seq (&seq, stmts);
558 g = gimple_build_assign (mf_base, t);
559 gimple_set_location (g, location);
560 gimple_seq_add_stmt (&seq, g);
562 /* Build: __mf_limit = (uintptr_t) <limit address expression>. */
563 t = fold_convert (mf_uintptr_type, unshare_expr (limit));
564 t = force_gimple_operand (t, &stmts, false, NULL_TREE);
565 gimple_seq_add_seq (&seq, stmts);
566 g = gimple_build_assign (mf_limit, t);
567 gimple_set_location (g, location);
568 gimple_seq_add_stmt (&seq, g);
570 /* Build: __mf_elem = &__mf_lookup_cache [(__mf_base >> __mf_shift)
572 t = build2 (RSHIFT_EXPR, mf_uintptr_type, mf_base,
573 flag_mudflap_threads ? mf_cache_shift_decl
574 : mf_cache_shift_decl_l);
575 t = build2 (BIT_AND_EXPR, mf_uintptr_type, t,
576 flag_mudflap_threads ? mf_cache_mask_decl
577 : mf_cache_mask_decl_l);
578 t = build4 (ARRAY_REF,
579 TREE_TYPE (TREE_TYPE (mf_cache_array_decl)),
580 mf_cache_array_decl, t, NULL_TREE, NULL_TREE);
581 t = build1 (ADDR_EXPR, mf_cache_structptr_type, t);
582 t = force_gimple_operand (t, &stmts, false, NULL_TREE);
583 gimple_seq_add_seq (&seq, stmts);
584 g = gimple_build_assign (mf_elem, t);
585 gimple_set_location (g, location);
586 gimple_seq_add_stmt (&seq, g);
588 /* Quick validity check.
590 if (__mf_elem->low > __mf_base
591 || (__mf_elem_high < __mf_limit))
594 ... and only if single-threaded:
595 __mf_lookup_shift_1 = f...;
596 __mf_lookup_mask_l = ...;
599 It is expected that this body of code is rarely executed so we mark
600 the edge to the THEN clause of the conditional jump as unlikely. */
602 /* Construct t <-- '__mf_elem->low > __mf_base'. */
603 t = build3 (COMPONENT_REF, mf_uintptr_type,
604 build1 (INDIRECT_REF, mf_cache_struct_type, mf_elem),
605 TYPE_FIELDS (mf_cache_struct_type), NULL_TREE);
606 t = build2 (GT_EXPR, boolean_type_node, t, mf_base);
608 /* Construct '__mf_elem->high < __mf_limit'.
611 1) u <-- '__mf_elem->high'
612 2) v <-- '__mf_limit'.
614 Then build 'u <-- (u < v). */
616 u = build3 (COMPONENT_REF, mf_uintptr_type,
617 build1 (INDIRECT_REF, mf_cache_struct_type, mf_elem),
618 TREE_CHAIN (TYPE_FIELDS (mf_cache_struct_type)), NULL_TREE);
622 u = build2 (LT_EXPR, boolean_type_node, u, v);
624 /* Build the composed conditional: t <-- 't || u'. Then store the
625 result of the evaluation of 't' in a temporary variable which we
626 can use as the condition for the conditional jump. */
627 t = build2 (TRUTH_OR_EXPR, boolean_type_node, t, u);
628 t = force_gimple_operand (t, &stmts, false, NULL_TREE);
629 gimple_seq_add_seq (&seq, stmts);
630 cond = create_tmp_var (boolean_type_node, "__mf_unlikely_cond");
631 g = gimple_build_assign (cond, t);
632 gimple_set_location (g, location);
633 gimple_seq_add_stmt (&seq, g);
635 /* Build the conditional jump. 'cond' is just a temporary so we can
636 simply build a void COND_EXPR. We do need labels in both arms though. */
637 g = gimple_build_cond (NE_EXPR, cond, integer_zero_node, NULL_TREE,
639 gimple_set_location (g, location);
640 gimple_seq_add_stmt (&seq, g);
642 /* At this point, after so much hard work, we have only constructed
643 the conditional jump,
645 if (__mf_elem->low > __mf_base
646 || (__mf_elem_high < __mf_limit))
648 The lowered GIMPLE tree representing this code is in the statement
649 list starting at 'head'.
651 We can insert this now in the current basic block, i.e. the one that
652 the statement we're instrumenting was originally in. */
653 gsi = gsi_last_bb (cond_bb);
654 gsi_insert_seq_after (&gsi, seq, GSI_CONTINUE_LINKING);
656 /* Now build up the body of the cache-miss handling:
661 This is the body of the conditional. */
663 seq = gimple_seq_alloc ();
664 /* u is a string, so it is already a gimple value. */
665 u = mf_file_function_line_tree (location);
666 /* NB: we pass the overall [base..limit] range to mf_check. */
667 v = fold_build2 (PLUS_EXPR, integer_type_node,
668 fold_build2 (MINUS_EXPR, mf_uintptr_type, mf_limit, mf_base),
670 v = force_gimple_operand (v, &stmts, true, NULL_TREE);
671 gimple_seq_add_seq (&seq, stmts);
672 g = gimple_build_call (mf_check_fndecl, 4, mf_base, v, dirflag, u);
673 gimple_seq_add_stmt (&seq, g);
675 if (! flag_mudflap_threads)
677 if (stmt_ends_bb_p (g))
679 gsi = gsi_start_bb (then_bb);
680 gsi_insert_seq_after (&gsi, seq, GSI_CONTINUE_LINKING);
681 e = split_block (then_bb, g);
683 seq = gimple_seq_alloc ();
686 g = gimple_build_assign (mf_cache_shift_decl_l, mf_cache_shift_decl);
687 gimple_seq_add_stmt (&seq, g);
689 g = gimple_build_assign (mf_cache_mask_decl_l, mf_cache_mask_decl);
690 gimple_seq_add_stmt (&seq, g);
693 /* Insert the check code in the THEN block. */
694 gsi = gsi_start_bb (then_bb);
695 gsi_insert_seq_after (&gsi, seq, GSI_CONTINUE_LINKING);
697 *instr_gsi = gsi_start_bb (join_bb);
701 /* Check whether the given decl, generally a VAR_DECL or PARM_DECL, is
702 eligible for instrumentation. For the mudflap1 pass, this implies
703 that it should be registered with the libmudflap runtime. For the
704 mudflap2 pass this means instrumenting an indirection operation with
705 respect to the object.
708 mf_decl_eligible_p (tree decl)
710 return ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
711 /* The decl must have its address taken. In the case of
712 arrays, this flag is also set if the indexes are not
713 compile-time known valid constants. */
714 /* XXX: not sufficient: return-by-value structs! */
715 && TREE_ADDRESSABLE (decl)
716 /* The type of the variable must be complete. */
717 && COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (decl))
718 /* The decl hasn't been decomposed somehow. */
719 && !DECL_HAS_VALUE_EXPR_P (decl));
724 mf_xform_derefs_1 (gimple_stmt_iterator *iter, tree *tp,
725 location_t location, tree dirflag)
727 tree type, base, limit, addr, size, t;
729 /* Don't instrument read operations. */
730 if (dirflag == integer_zero_node && flag_mudflap_ignore_reads)
733 /* Don't instrument marked nodes. */
734 if (mf_marked_p (*tp))
738 type = TREE_TYPE (t);
740 if (type == error_mark_node)
743 size = TYPE_SIZE_UNIT (type);
745 switch (TREE_CODE (t))
750 /* This is trickier than it may first appear. The reason is
751 that we are looking at expressions from the "inside out" at
752 this point. We may have a complex nested aggregate/array
753 expression (e.g. "a.b[i].c"), maybe with an indirection as
754 the leftmost operator ("p->a.b.d"), where instrumentation
755 is necessary. Or we may have an innocent "a.b.c"
756 expression that must not be instrumented. We need to
757 recurse all the way down the nesting structure to figure it
758 out: looking just at the outer node is not enough. */
760 int component_ref_only = (TREE_CODE (t) == COMPONENT_REF);
761 /* If we have a bitfield component reference, we must note the
762 innermost addressable object in ELT, from which we will
763 construct the byte-addressable bounds of the bitfield. */
764 tree elt = NULL_TREE;
765 int bitfield_ref_p = (TREE_CODE (t) == COMPONENT_REF
766 && DECL_BIT_FIELD_TYPE (TREE_OPERAND (t, 1)));
768 /* Iterate to the top of the ARRAY_REF/COMPONENT_REF
769 containment hierarchy to find the outermost VAR_DECL. */
770 var = TREE_OPERAND (t, 0);
773 if (bitfield_ref_p && elt == NULL_TREE
774 && (TREE_CODE (var) == ARRAY_REF
775 || TREE_CODE (var) == COMPONENT_REF))
778 if (TREE_CODE (var) == ARRAY_REF)
780 component_ref_only = 0;
781 var = TREE_OPERAND (var, 0);
783 else if (TREE_CODE (var) == COMPONENT_REF)
784 var = TREE_OPERAND (var, 0);
785 else if (INDIRECT_REF_P (var))
787 base = TREE_OPERAND (var, 0);
790 else if (TREE_CODE (var) == VIEW_CONVERT_EXPR)
792 var = TREE_OPERAND (var, 0);
793 if (CONSTANT_CLASS_P (var)
794 && TREE_CODE (var) != STRING_CST)
799 gcc_assert (TREE_CODE (var) == VAR_DECL
800 || TREE_CODE (var) == PARM_DECL
801 || TREE_CODE (var) == RESULT_DECL
802 || TREE_CODE (var) == STRING_CST);
803 /* Don't instrument this access if the underlying
804 variable is not "eligible". This test matches
805 those arrays that have only known-valid indexes,
806 and thus are not labeled TREE_ADDRESSABLE. */
807 if (! mf_decl_eligible_p (var) || component_ref_only)
811 base = build1 (ADDR_EXPR,
812 build_pointer_type (TREE_TYPE (var)), var);
818 /* Handle the case of ordinary non-indirection structure
819 accesses. These have only nested COMPONENT_REF nodes (no
820 INDIRECT_REF), but pass through the above filter loop.
821 Note that it's possible for such a struct variable to match
822 the eligible_p test because someone else might take its
825 /* We need special processing for bitfield components, because
826 their addresses cannot be taken. */
829 tree field = TREE_OPERAND (t, 1);
831 if (TREE_CODE (DECL_SIZE_UNIT (field)) == INTEGER_CST)
832 size = DECL_SIZE_UNIT (field);
835 elt = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (elt)),
837 addr = fold_convert (ptr_type_node, elt ? elt : base);
838 addr = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
839 addr, fold_convert (sizetype,
840 byte_position (field)));
843 addr = build1 (ADDR_EXPR, build_pointer_type (type), t);
845 limit = fold_build2 (MINUS_EXPR, mf_uintptr_type,
846 fold_build2 (PLUS_EXPR, mf_uintptr_type,
847 convert (mf_uintptr_type, addr),
854 addr = TREE_OPERAND (t, 0);
856 limit = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
857 fold_build2 (POINTER_PLUS_EXPR, ptr_type_node, base,
863 addr = tree_mem_ref_addr (ptr_type_node, t);
865 limit = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
866 fold_build2 (POINTER_PLUS_EXPR, ptr_type_node, base,
871 case ARRAY_RANGE_REF:
872 warning (OPT_Wmudflap,
873 "mudflap checking not yet implemented for ARRAY_RANGE_REF");
877 /* ??? merge with COMPONENT_REF code above? */
881 /* If we're not dereferencing something, then the access
883 if (TREE_CODE (TREE_OPERAND (t, 0)) != INDIRECT_REF)
886 bpu = bitsize_int (BITS_PER_UNIT);
887 ofs = convert (bitsizetype, TREE_OPERAND (t, 2));
888 rem = size_binop (TRUNC_MOD_EXPR, ofs, bpu);
889 ofs = fold_convert (sizetype, size_binop (TRUNC_DIV_EXPR, ofs, bpu));
891 size = convert (bitsizetype, TREE_OPERAND (t, 1));
892 size = size_binop (PLUS_EXPR, size, rem);
893 size = size_binop (CEIL_DIV_EXPR, size, bpu);
894 size = convert (sizetype, size);
896 addr = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
897 addr = convert (ptr_type_node, addr);
898 addr = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node, addr, ofs);
901 limit = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
902 fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
912 mf_build_check_statement_for (base, limit, iter, location, dirflag);
916 mf_xform_derefs (void)
918 basic_block bb, next;
919 gimple_stmt_iterator i;
920 int saved_last_basic_block = last_basic_block;
921 enum gimple_rhs_class grhs_class;
923 bb = ENTRY_BLOCK_PTR ->next_bb;
927 for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i))
929 gimple s = gsi_stmt (i);
931 /* Only a few GIMPLE statements can reference memory. */
932 switch (gimple_code (s))
935 mf_xform_derefs_1 (&i, gimple_assign_lhs_ptr (s),
936 gimple_location (s), integer_one_node);
937 mf_xform_derefs_1 (&i, gimple_assign_rhs1_ptr (s),
938 gimple_location (s), integer_zero_node);
939 grhs_class = get_gimple_rhs_class (gimple_assign_rhs_code (s));
940 if (grhs_class == GIMPLE_BINARY_RHS)
941 mf_xform_derefs_1 (&i, gimple_assign_rhs2_ptr (s),
942 gimple_location (s), integer_zero_node);
946 if (gimple_return_retval (s) != NULL_TREE)
948 mf_xform_derefs_1 (&i, gimple_return_retval_ptr (s),
960 while (bb && bb->index <= saved_last_basic_block);
963 /* ------------------------------------------------------------------------ */
964 /* ADDR_EXPR transforms. Perform the declaration-related mudflap tree
965 transforms on the current function.
967 This is the first part of the mudflap instrumentation. It works on
968 high-level GIMPLE because after lowering, all variables are moved out
969 of their BIND_EXPR binding context, and we lose liveness information
970 for the declarations we wish to instrument. */
973 execute_mudflap_function_decls (void)
975 struct gimplify_ctx gctx;
977 /* Don't instrument functions such as the synthetic constructor
978 built during mudflap_finish_file. */
979 if (mf_marked_p (current_function_decl) ||
980 DECL_ARTIFICIAL (current_function_decl))
983 push_gimplify_context (&gctx);
985 mf_xform_decls (gimple_body (current_function_decl),
986 DECL_ARGUMENTS (current_function_decl));
988 pop_gimplify_context (NULL);
992 /* This struct is passed between mf_xform_decls to store state needed
993 during the traversal searching for objects that have their
995 struct mf_xform_decls_data
1001 /* Synthesize a CALL_EXPR and a TRY_FINALLY_EXPR, for this chain of
1002 _DECLs if appropriate. Arrange to call the __mf_register function
1003 now, and the __mf_unregister function later for each. Return the
1004 gimple sequence after synthesis. */
1006 mx_register_decls (tree decl, gimple_seq seq, location_t location)
1008 gimple_seq finally_stmts = NULL;
1009 gimple_stmt_iterator initially_stmts = gsi_start (seq);
1011 while (decl != NULL_TREE)
1013 if (mf_decl_eligible_p (decl)
1014 /* Not already processed. */
1015 && ! mf_marked_p (decl)
1016 /* Automatic variable. */
1017 && ! DECL_EXTERNAL (decl)
1018 && ! TREE_STATIC (decl))
1020 tree size = NULL_TREE, variable_name;
1021 gimple unregister_fncall, register_fncall;
1022 tree unregister_fncall_param, register_fncall_param;
1024 /* Variable-sized objects should have sizes already been
1025 gimplified when we got here. */
1026 size = convert (size_type_node, TYPE_SIZE_UNIT (TREE_TYPE (decl)));
1027 gcc_assert (is_gimple_val (size));
1030 unregister_fncall_param =
1031 mf_mark (build1 (ADDR_EXPR,
1032 build_pointer_type (TREE_TYPE (decl)),
1034 /* __mf_unregister (&VARIABLE, sizeof (VARIABLE), __MF_TYPE_STACK) */
1035 unregister_fncall = gimple_build_call (mf_unregister_fndecl, 3,
1036 unregister_fncall_param,
1038 build_int_cst (NULL_TREE, 3));
1041 variable_name = mf_varname_tree (decl);
1042 register_fncall_param =
1043 mf_mark (build1 (ADDR_EXPR,
1044 build_pointer_type (TREE_TYPE (decl)),
1046 /* __mf_register (&VARIABLE, sizeof (VARIABLE), __MF_TYPE_STACK,
1048 register_fncall = gimple_build_call (mf_register_fndecl, 4,
1049 register_fncall_param,
1051 build_int_cst (NULL_TREE, 3),
1055 /* Accumulate the two calls. */
1056 gimple_set_location (register_fncall, location);
1057 gimple_set_location (unregister_fncall, location);
1059 /* Add the __mf_register call at the current appending point. */
1060 if (gsi_end_p (initially_stmts))
1062 if (!DECL_ARTIFICIAL (decl))
1063 warning (OPT_Wmudflap,
1064 "mudflap cannot track %qs in stub function",
1065 IDENTIFIER_POINTER (DECL_NAME (decl)));
1069 gsi_insert_before (&initially_stmts, register_fncall,
1072 /* Accumulate the FINALLY piece. */
1073 gimple_seq_add_stmt (&finally_stmts, unregister_fncall);
1078 decl = TREE_CHAIN (decl);
1081 /* Actually, (initially_stmts!=NULL) <=> (finally_stmts!=NULL) */
1082 if (finally_stmts != NULL)
1084 gimple stmt = gimple_build_try (seq, finally_stmts, GIMPLE_TRY_FINALLY);
1085 gimple_seq new_seq = gimple_seq_alloc ();
1087 gimple_seq_add_stmt (&new_seq, stmt);
1095 /* Process every variable mentioned in BIND_EXPRs. */
1097 mx_xfn_xform_decls (gimple_stmt_iterator *gsi,
1098 bool *handled_operands_p ATTRIBUTE_UNUSED,
1099 struct walk_stmt_info *wi)
1101 struct mf_xform_decls_data *d = (struct mf_xform_decls_data *) wi->info;
1102 gimple stmt = gsi_stmt (*gsi);
1104 switch (gimple_code (stmt))
1108 /* Process function parameters now (but only once). */
1111 gimple_bind_set_body (stmt,
1112 mx_register_decls (d->param_decls,
1113 gimple_bind_body (stmt),
1114 gimple_location (stmt)));
1115 d->param_decls = NULL_TREE;
1118 gimple_bind_set_body (stmt,
1119 mx_register_decls (gimple_bind_vars (stmt),
1120 gimple_bind_body (stmt),
1121 gimple_location (stmt)));
1132 /* Perform the object lifetime tracking mudflap transform on the given function
1133 tree. The tree is mutated in place, with possibly copied subtree nodes.
1135 For every auto variable declared, if its address is ever taken
1136 within the function, then supply its lifetime to the mudflap
1137 runtime with the __mf_register and __mf_unregister calls.
1141 mf_xform_decls (gimple_seq fnbody, tree fnparams)
1143 struct mf_xform_decls_data d;
1144 struct walk_stmt_info wi;
1145 struct pointer_set_t *pset = pointer_set_create ();
1147 d.param_decls = fnparams;
1148 memset (&wi, 0, sizeof (wi));
1149 wi.info = (void*) &d;
1151 walk_gimple_seq (fnbody, mx_xfn_xform_decls, NULL, &wi);
1152 pointer_set_destroy (pset);
1156 /* ------------------------------------------------------------------------ */
1157 /* Externally visible mudflap functions. */
1160 /* Mark and return the given tree node to prevent further mudflap
1162 static GTY ((param_is (union tree_node))) htab_t marked_trees = NULL;
1169 if (marked_trees == NULL)
1170 marked_trees = htab_create_ggc (31, htab_hash_pointer, htab_eq_pointer,
1173 slot = htab_find_slot (marked_trees, t, INSERT);
1179 mf_marked_p (tree t)
1183 if (marked_trees == NULL)
1186 entry = htab_find (marked_trees, t);
1187 return (entry != NULL);
1190 /* Remember given node as a static of some kind: global data,
1191 function-scope static, or an anonymous constant. Its assembler
1194 /* A list of globals whose incomplete declarations we encountered.
1195 Instead of emitting the __mf_register call for them here, it's
1196 delayed until program finish time. If they're still incomplete by
1197 then, warnings are emitted. */
1199 static GTY (()) VEC(tree,gc) *deferred_static_decls;
1201 /* A list of statements for calling __mf_register() at startup time. */
1202 static GTY (()) tree enqueued_call_stmt_chain;
1205 mudflap_register_call (tree obj, tree object_size, tree varname)
1207 tree arg, call_stmt;
1209 arg = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (obj)), obj);
1210 arg = convert (ptr_type_node, arg);
1212 call_stmt = build_call_expr (mf_register_fndecl, 4,
1214 convert (size_type_node, object_size),
1215 /* __MF_TYPE_STATIC */
1216 build_int_cst (NULL_TREE, 4),
1219 append_to_statement_list (call_stmt, &enqueued_call_stmt_chain);
1223 mudflap_enqueue_decl (tree obj)
1225 if (mf_marked_p (obj))
1228 /* We don't need to process variable decls that are internally
1229 generated extern. If we did, we'd end up with warnings for them
1230 during mudflap_finish_file (). That would confuse the user,
1231 since the text would refer to variables that don't show up in the
1232 user's source code. */
1233 if (DECL_P (obj) && DECL_EXTERNAL (obj) && DECL_ARTIFICIAL (obj))
1236 VEC_safe_push (tree, gc, deferred_static_decls, obj);
1241 mudflap_enqueue_constant (tree obj)
1243 tree object_size, varname;
1245 if (mf_marked_p (obj))
1248 if (TREE_CODE (obj) == STRING_CST)
1249 object_size = build_int_cst (NULL_TREE, TREE_STRING_LENGTH (obj));
1251 object_size = size_in_bytes (TREE_TYPE (obj));
1253 if (TREE_CODE (obj) == STRING_CST)
1254 varname = mf_build_string ("string literal");
1256 varname = mf_build_string ("constant");
1258 mudflap_register_call (obj, object_size, varname);
1262 /* Emit any file-wide instrumentation. */
1264 mudflap_finish_file (void)
1266 tree ctor_statements = NULL_TREE;
1268 /* No need to continue when there were errors. */
1269 if (errorcount != 0 || sorrycount != 0)
1272 /* Insert a call to __mf_init. */
1274 tree call2_stmt = build_call_expr (mf_init_fndecl, 0);
1275 append_to_statement_list (call2_stmt, &ctor_statements);
1278 /* If appropriate, call __mf_set_options to pass along read-ignore mode. */
1279 if (flag_mudflap_ignore_reads)
1281 tree arg = mf_build_string ("-ignore-reads");
1282 tree call_stmt = build_call_expr (mf_set_options_fndecl, 1, arg);
1283 append_to_statement_list (call_stmt, &ctor_statements);
1286 /* Process all enqueued object decls. */
1287 if (deferred_static_decls)
1291 for (i = 0; VEC_iterate (tree, deferred_static_decls, i, obj); i++)
1293 gcc_assert (DECL_P (obj));
1295 if (mf_marked_p (obj))
1298 /* Omit registration for static unaddressed objects. NB:
1299 Perform registration for non-static objects regardless of
1300 TREE_USED or TREE_ADDRESSABLE, because they may be used
1301 from other compilation units. */
1302 if (! TREE_PUBLIC (obj) && ! TREE_ADDRESSABLE (obj))
1305 if (! COMPLETE_TYPE_P (TREE_TYPE (obj)))
1307 warning (OPT_Wmudflap,
1308 "mudflap cannot track unknown size extern %qs",
1309 IDENTIFIER_POINTER (DECL_NAME (obj)));
1313 mudflap_register_call (obj,
1314 size_in_bytes (TREE_TYPE (obj)),
1315 mf_varname_tree (obj));
1318 VEC_truncate (tree, deferred_static_decls, 0);
1321 /* Append all the enqueued registration calls. */
1322 if (enqueued_call_stmt_chain)
1324 append_to_statement_list (enqueued_call_stmt_chain, &ctor_statements);
1325 enqueued_call_stmt_chain = NULL_TREE;
1328 cgraph_build_static_cdtor ('I', ctor_statements,
1329 MAX_RESERVED_INIT_PRIORITY-1);
1336 return flag_mudflap != 0;
1339 struct gimple_opt_pass pass_mudflap_1 =
1343 "mudflap1", /* name */
1344 gate_mudflap, /* gate */
1345 execute_mudflap_function_decls, /* execute */
1348 0, /* static_pass_number */
1350 PROP_gimple_any, /* properties_required */
1351 0, /* properties_provided */
1352 0, /* properties_destroyed */
1353 0, /* todo_flags_start */
1354 TODO_dump_func /* todo_flags_finish */
1358 struct gimple_opt_pass pass_mudflap_2 =
1362 "mudflap2", /* name */
1363 gate_mudflap, /* gate */
1364 execute_mudflap_function_ops, /* execute */
1367 0, /* static_pass_number */
1369 PROP_gimple_leh, /* properties_required */
1370 0, /* properties_provided */
1371 0, /* properties_destroyed */
1372 0, /* todo_flags_start */
1373 TODO_verify_flow | TODO_verify_stmts
1374 | TODO_dump_func /* todo_flags_finish */
1378 #include "gt-tree-mudflap.h"