1 /* Mudflap: narrow-pointer bounds-checking by tree rewriting.
2 Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
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 (UNKNOWN_LOCATION,
299 category, get_identifier (name), type));
300 TREE_PUBLIC (decl) = 1;
301 DECL_EXTERNAL (decl) = 1;
302 lang_hooks.decls.pushdecl (decl);
303 /* The decl was declared by the compiler. */
304 DECL_ARTIFICIAL (decl) = 1;
305 /* And we don't want debug info for it. */
306 DECL_IGNORED_P (decl) = 1;
310 /* Helper for mudflap_init: construct a tree corresponding to the type
311 struct __mf_cache { uintptr_t low; uintptr_t high; };
312 where uintptr_t is the FIELD_TYPE argument. */
314 mf_make_mf_cache_struct_type (tree field_type)
316 /* There is, abominably, no language-independent way to construct a
317 RECORD_TYPE. So we have to call the basic type construction
318 primitives by hand. */
319 tree fieldlo = build_decl (UNKNOWN_LOCATION,
320 FIELD_DECL, get_identifier ("low"), field_type);
321 tree fieldhi = build_decl (UNKNOWN_LOCATION,
322 FIELD_DECL, get_identifier ("high"), field_type);
324 tree struct_type = make_node (RECORD_TYPE);
325 DECL_CONTEXT (fieldlo) = struct_type;
326 DECL_CONTEXT (fieldhi) = struct_type;
327 TREE_CHAIN (fieldlo) = fieldhi;
328 TYPE_FIELDS (struct_type) = fieldlo;
329 TYPE_NAME (struct_type) = get_identifier ("__mf_cache");
330 layout_type (struct_type);
335 #define build_function_type_0(rtype) \
336 build_function_type (rtype, void_list_node)
337 #define build_function_type_1(rtype, arg1) \
338 build_function_type (rtype, tree_cons (0, arg1, void_list_node))
339 #define build_function_type_3(rtype, arg1, arg2, arg3) \
340 build_function_type (rtype, \
341 tree_cons (0, arg1, \
342 tree_cons (0, arg2, \
343 tree_cons (0, arg3, \
345 #define build_function_type_4(rtype, arg1, arg2, arg3, arg4) \
346 build_function_type (rtype, \
347 tree_cons (0, arg1, \
348 tree_cons (0, arg2, \
349 tree_cons (0, arg3, \
350 tree_cons (0, arg4, \
353 /* Initialize the global tree nodes that correspond to mf-runtime.h
358 static bool done = false;
359 tree mf_const_string_type;
360 tree mf_cache_array_type;
361 tree mf_check_register_fntype;
362 tree mf_unregister_fntype;
364 tree mf_set_options_fntype;
370 mf_uintptr_type = lang_hooks.types.type_for_mode (ptr_mode,
373 = build_pointer_type (build_qualified_type
374 (char_type_node, TYPE_QUAL_CONST));
376 mf_cache_struct_type = mf_make_mf_cache_struct_type (mf_uintptr_type);
377 mf_cache_structptr_type = build_pointer_type (mf_cache_struct_type);
378 mf_cache_array_type = build_array_type (mf_cache_struct_type, 0);
379 mf_check_register_fntype =
380 build_function_type_4 (void_type_node, ptr_type_node, size_type_node,
381 integer_type_node, mf_const_string_type);
382 mf_unregister_fntype =
383 build_function_type_3 (void_type_node, ptr_type_node, size_type_node,
386 build_function_type_0 (void_type_node);
387 mf_set_options_fntype =
388 build_function_type_1 (integer_type_node, mf_const_string_type);
390 mf_cache_array_decl = mf_make_builtin (VAR_DECL, "__mf_lookup_cache",
391 mf_cache_array_type);
392 mf_cache_shift_decl = mf_make_builtin (VAR_DECL, "__mf_lc_shift",
393 unsigned_char_type_node);
394 mf_cache_mask_decl = mf_make_builtin (VAR_DECL, "__mf_lc_mask",
396 /* Don't process these in mudflap_enqueue_decl, should they come by
397 there for some reason. */
398 mf_mark (mf_cache_array_decl);
399 mf_mark (mf_cache_shift_decl);
400 mf_mark (mf_cache_mask_decl);
401 mf_check_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_check",
402 mf_check_register_fntype);
403 mf_register_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_register",
404 mf_check_register_fntype);
405 mf_unregister_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_unregister",
406 mf_unregister_fntype);
407 mf_init_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_init",
409 mf_set_options_fndecl = mf_make_builtin (FUNCTION_DECL, "__mf_set_options",
410 mf_set_options_fntype);
412 #undef build_function_type_4
413 #undef build_function_type_3
414 #undef build_function_type_1
415 #undef build_function_type_0
418 /* ------------------------------------------------------------------------ */
419 /* Memory reference transforms. Perform the mudflap indirection-related
420 tree transforms on the current function.
422 This is the second part of the mudflap instrumentation. It works on
423 low-level GIMPLE using the CFG, because we want to run this pass after
424 tree optimizations have been performed, but we have to preserve the CFG
425 for expansion from trees to RTL. */
428 execute_mudflap_function_ops (void)
430 struct gimplify_ctx gctx;
432 /* Don't instrument functions such as the synthetic constructor
433 built during mudflap_finish_file. */
434 if (mf_marked_p (current_function_decl) ||
435 DECL_ARTIFICIAL (current_function_decl))
438 push_gimplify_context (&gctx);
440 /* In multithreaded mode, don't cache the lookup cache parameters. */
441 if (! flag_mudflap_threads)
442 mf_decl_cache_locals ();
446 if (! flag_mudflap_threads)
447 mf_decl_clear_locals ();
449 pop_gimplify_context (NULL);
453 /* Insert a gimple_seq SEQ on all the outgoing edges out of BB. Note that
454 if BB has more than one edge, STMT will be replicated for each edge.
455 Also, abnormal edges will be ignored. */
458 insert_edge_copies_seq (gimple_seq seq, basic_block bb)
462 unsigned n_copies = -1;
464 FOR_EACH_EDGE (e, ei, bb->succs)
465 if (!(e->flags & EDGE_ABNORMAL))
468 FOR_EACH_EDGE (e, ei, bb->succs)
469 if (!(e->flags & EDGE_ABNORMAL))
470 gsi_insert_seq_on_edge (e, n_copies-- > 0 ? gimple_seq_copy (seq) : seq);
473 /* Create and initialize local shadow variables for the lookup cache
474 globals. Put their decls in the *_l globals for use by
475 mf_build_check_statement_for. */
478 mf_decl_cache_locals (void)
481 gimple_seq seq = gimple_seq_alloc ();
483 /* Build the cache vars. */
484 mf_cache_shift_decl_l
485 = mf_mark (make_rename_temp (TREE_TYPE (mf_cache_shift_decl),
486 "__mf_lookup_shift_l"));
489 = mf_mark (make_rename_temp (TREE_TYPE (mf_cache_mask_decl),
490 "__mf_lookup_mask_l"));
492 /* Build initialization nodes for the cache vars. We just load the
493 globals into the cache variables. */
494 g = gimple_build_assign (mf_cache_shift_decl_l, mf_cache_shift_decl);
495 gimple_set_location (g, DECL_SOURCE_LOCATION (current_function_decl));
496 gimple_seq_add_stmt (&seq, g);
498 g = gimple_build_assign (mf_cache_mask_decl_l, mf_cache_mask_decl);
499 gimple_set_location (g, DECL_SOURCE_LOCATION (current_function_decl));
500 gimple_seq_add_stmt (&seq, g);
502 insert_edge_copies_seq (seq, ENTRY_BLOCK_PTR);
504 gsi_commit_edge_inserts ();
509 mf_decl_clear_locals (void)
511 /* Unset local shadows. */
512 mf_cache_shift_decl_l = NULL_TREE;
513 mf_cache_mask_decl_l = NULL_TREE;
517 mf_build_check_statement_for (tree base, tree limit,
518 gimple_stmt_iterator *instr_gsi,
519 location_t location, tree dirflag)
521 gimple_stmt_iterator gsi;
522 basic_block cond_bb, then_bb, join_bb;
529 gimple_seq seq, stmts;
531 /* We first need to split the current basic block, and start altering
532 the CFG. This allows us to insert the statements we're about to
533 construct into the right basic blocks. */
535 cond_bb = gimple_bb (gsi_stmt (*instr_gsi));
538 if (! gsi_end_p (gsi))
539 e = split_block (cond_bb, gsi_stmt (gsi));
541 e = split_block_after_labels (cond_bb);
545 /* A recap at this point: join_bb is the basic block at whose head
546 is the gimple statement for which this check expression is being
547 built. cond_bb is the (possibly new, synthetic) basic block the
548 end of which will contain the cache-lookup code, and a
549 conditional that jumps to the cache-miss code or, much more
550 likely, over to join_bb. */
552 /* Create the bb that contains the cache-miss fallback block (mf_check). */
553 then_bb = create_empty_bb (cond_bb);
554 make_edge (cond_bb, then_bb, EDGE_TRUE_VALUE);
555 make_single_succ_edge (then_bb, join_bb, EDGE_FALLTHRU);
557 /* Mark the pseudo-fallthrough edge from cond_bb to join_bb. */
558 e = find_edge (cond_bb, join_bb);
559 e->flags = EDGE_FALSE_VALUE;
560 e->count = cond_bb->count;
561 e->probability = REG_BR_PROB_BASE;
563 /* Update dominance info. Note that bb_join's data was
564 updated by split_block. */
565 if (dom_info_available_p (CDI_DOMINATORS))
567 set_immediate_dominator (CDI_DOMINATORS, then_bb, cond_bb);
568 set_immediate_dominator (CDI_DOMINATORS, join_bb, cond_bb);
571 /* Build our local variables. */
572 mf_elem = make_rename_temp (mf_cache_structptr_type, "__mf_elem");
573 mf_base = make_rename_temp (mf_uintptr_type, "__mf_base");
574 mf_limit = make_rename_temp (mf_uintptr_type, "__mf_limit");
576 /* Build: __mf_base = (uintptr_t) <base address expression>. */
577 seq = gimple_seq_alloc ();
578 t = fold_convert (mf_uintptr_type, unshare_expr (base));
579 t = force_gimple_operand (t, &stmts, false, NULL_TREE);
580 gimple_seq_add_seq (&seq, stmts);
581 g = gimple_build_assign (mf_base, t);
582 gimple_set_location (g, location);
583 gimple_seq_add_stmt (&seq, g);
585 /* Build: __mf_limit = (uintptr_t) <limit address expression>. */
586 t = fold_convert (mf_uintptr_type, unshare_expr (limit));
587 t = force_gimple_operand (t, &stmts, false, NULL_TREE);
588 gimple_seq_add_seq (&seq, stmts);
589 g = gimple_build_assign (mf_limit, t);
590 gimple_set_location (g, location);
591 gimple_seq_add_stmt (&seq, g);
593 /* Build: __mf_elem = &__mf_lookup_cache [(__mf_base >> __mf_shift)
595 t = build2 (RSHIFT_EXPR, mf_uintptr_type, mf_base,
596 flag_mudflap_threads ? mf_cache_shift_decl
597 : mf_cache_shift_decl_l);
598 t = build2 (BIT_AND_EXPR, mf_uintptr_type, t,
599 flag_mudflap_threads ? mf_cache_mask_decl
600 : mf_cache_mask_decl_l);
601 t = build4 (ARRAY_REF,
602 TREE_TYPE (TREE_TYPE (mf_cache_array_decl)),
603 mf_cache_array_decl, t, NULL_TREE, NULL_TREE);
604 t = build1 (ADDR_EXPR, mf_cache_structptr_type, t);
605 t = force_gimple_operand (t, &stmts, false, NULL_TREE);
606 gimple_seq_add_seq (&seq, stmts);
607 g = gimple_build_assign (mf_elem, t);
608 gimple_set_location (g, location);
609 gimple_seq_add_stmt (&seq, g);
611 /* Quick validity check.
613 if (__mf_elem->low > __mf_base
614 || (__mf_elem_high < __mf_limit))
617 ... and only if single-threaded:
618 __mf_lookup_shift_1 = f...;
619 __mf_lookup_mask_l = ...;
622 It is expected that this body of code is rarely executed so we mark
623 the edge to the THEN clause of the conditional jump as unlikely. */
625 /* Construct t <-- '__mf_elem->low > __mf_base'. */
626 t = build3 (COMPONENT_REF, mf_uintptr_type,
627 build1 (INDIRECT_REF, mf_cache_struct_type, mf_elem),
628 TYPE_FIELDS (mf_cache_struct_type), NULL_TREE);
629 t = build2 (GT_EXPR, boolean_type_node, t, mf_base);
631 /* Construct '__mf_elem->high < __mf_limit'.
634 1) u <-- '__mf_elem->high'
635 2) v <-- '__mf_limit'.
637 Then build 'u <-- (u < v). */
639 u = build3 (COMPONENT_REF, mf_uintptr_type,
640 build1 (INDIRECT_REF, mf_cache_struct_type, mf_elem),
641 TREE_CHAIN (TYPE_FIELDS (mf_cache_struct_type)), NULL_TREE);
645 u = build2 (LT_EXPR, boolean_type_node, u, v);
647 /* Build the composed conditional: t <-- 't || u'. Then store the
648 result of the evaluation of 't' in a temporary variable which we
649 can use as the condition for the conditional jump. */
650 t = build2 (TRUTH_OR_EXPR, boolean_type_node, t, u);
651 t = force_gimple_operand (t, &stmts, false, NULL_TREE);
652 gimple_seq_add_seq (&seq, stmts);
653 cond = make_rename_temp (boolean_type_node, "__mf_unlikely_cond");
654 g = gimple_build_assign (cond, t);
655 gimple_set_location (g, location);
656 gimple_seq_add_stmt (&seq, g);
658 /* Build the conditional jump. 'cond' is just a temporary so we can
659 simply build a void COND_EXPR. We do need labels in both arms though. */
660 g = gimple_build_cond (NE_EXPR, cond, boolean_false_node, NULL_TREE,
662 gimple_set_location (g, location);
663 gimple_seq_add_stmt (&seq, g);
665 /* At this point, after so much hard work, we have only constructed
666 the conditional jump,
668 if (__mf_elem->low > __mf_base
669 || (__mf_elem_high < __mf_limit))
671 The lowered GIMPLE tree representing this code is in the statement
672 list starting at 'head'.
674 We can insert this now in the current basic block, i.e. the one that
675 the statement we're instrumenting was originally in. */
676 gsi = gsi_last_bb (cond_bb);
677 gsi_insert_seq_after (&gsi, seq, GSI_CONTINUE_LINKING);
679 /* Now build up the body of the cache-miss handling:
684 This is the body of the conditional. */
686 seq = gimple_seq_alloc ();
687 /* u is a string, so it is already a gimple value. */
688 u = mf_file_function_line_tree (location);
689 /* NB: we pass the overall [base..limit] range to mf_check. */
690 v = fold_build2 (PLUS_EXPR, mf_uintptr_type,
691 fold_build2 (MINUS_EXPR, mf_uintptr_type, mf_limit, mf_base),
692 build_int_cst (mf_uintptr_type, 1));
693 v = force_gimple_operand (v, &stmts, true, NULL_TREE);
694 gimple_seq_add_seq (&seq, stmts);
695 g = gimple_build_call (mf_check_fndecl, 4, mf_base, v, dirflag, u);
696 gimple_seq_add_stmt (&seq, g);
698 if (! flag_mudflap_threads)
700 if (stmt_ends_bb_p (g))
702 gsi = gsi_start_bb (then_bb);
703 gsi_insert_seq_after (&gsi, seq, GSI_CONTINUE_LINKING);
704 e = split_block (then_bb, g);
706 seq = gimple_seq_alloc ();
709 g = gimple_build_assign (mf_cache_shift_decl_l, mf_cache_shift_decl);
710 gimple_seq_add_stmt (&seq, g);
712 g = gimple_build_assign (mf_cache_mask_decl_l, mf_cache_mask_decl);
713 gimple_seq_add_stmt (&seq, g);
716 /* Insert the check code in the THEN block. */
717 gsi = gsi_start_bb (then_bb);
718 gsi_insert_seq_after (&gsi, seq, GSI_CONTINUE_LINKING);
720 *instr_gsi = gsi_start_bb (join_bb);
724 /* Check whether the given decl, generally a VAR_DECL or PARM_DECL, is
725 eligible for instrumentation. For the mudflap1 pass, this implies
726 that it should be registered with the libmudflap runtime. For the
727 mudflap2 pass this means instrumenting an indirection operation with
728 respect to the object.
731 mf_decl_eligible_p (tree decl)
733 return ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
734 /* The decl must have its address taken. In the case of
735 arrays, this flag is also set if the indexes are not
736 compile-time known valid constants. */
737 /* XXX: not sufficient: return-by-value structs! */
738 && TREE_ADDRESSABLE (decl)
739 /* The type of the variable must be complete. */
740 && COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (decl))
741 /* The decl hasn't been decomposed somehow. */
742 && !DECL_HAS_VALUE_EXPR_P (decl));
747 mf_xform_derefs_1 (gimple_stmt_iterator *iter, tree *tp,
748 location_t location, tree dirflag)
750 tree type, base, limit, addr, size, t;
752 /* Don't instrument read operations. */
753 if (dirflag == integer_zero_node && flag_mudflap_ignore_reads)
756 /* Don't instrument marked nodes. */
757 if (mf_marked_p (*tp))
761 type = TREE_TYPE (t);
763 if (type == error_mark_node)
766 size = TYPE_SIZE_UNIT (type);
768 switch (TREE_CODE (t))
773 /* This is trickier than it may first appear. The reason is
774 that we are looking at expressions from the "inside out" at
775 this point. We may have a complex nested aggregate/array
776 expression (e.g. "a.b[i].c"), maybe with an indirection as
777 the leftmost operator ("p->a.b.d"), where instrumentation
778 is necessary. Or we may have an innocent "a.b.c"
779 expression that must not be instrumented. We need to
780 recurse all the way down the nesting structure to figure it
781 out: looking just at the outer node is not enough. */
783 int component_ref_only = (TREE_CODE (t) == COMPONENT_REF);
784 /* If we have a bitfield component reference, we must note the
785 innermost addressable object in ELT, from which we will
786 construct the byte-addressable bounds of the bitfield. */
787 tree elt = NULL_TREE;
788 int bitfield_ref_p = (TREE_CODE (t) == COMPONENT_REF
789 && DECL_BIT_FIELD_TYPE (TREE_OPERAND (t, 1)));
791 /* Iterate to the top of the ARRAY_REF/COMPONENT_REF
792 containment hierarchy to find the outermost VAR_DECL. */
793 var = TREE_OPERAND (t, 0);
796 if (bitfield_ref_p && elt == NULL_TREE
797 && (TREE_CODE (var) == ARRAY_REF
798 || TREE_CODE (var) == COMPONENT_REF))
801 if (TREE_CODE (var) == ARRAY_REF)
803 component_ref_only = 0;
804 var = TREE_OPERAND (var, 0);
806 else if (TREE_CODE (var) == COMPONENT_REF)
807 var = TREE_OPERAND (var, 0);
808 else if (INDIRECT_REF_P (var))
810 base = TREE_OPERAND (var, 0);
813 else if (TREE_CODE (var) == VIEW_CONVERT_EXPR)
815 var = TREE_OPERAND (var, 0);
816 if (CONSTANT_CLASS_P (var)
817 && TREE_CODE (var) != STRING_CST)
822 gcc_assert (TREE_CODE (var) == VAR_DECL
823 || TREE_CODE (var) == PARM_DECL
824 || TREE_CODE (var) == RESULT_DECL
825 || TREE_CODE (var) == STRING_CST);
826 /* Don't instrument this access if the underlying
827 variable is not "eligible". This test matches
828 those arrays that have only known-valid indexes,
829 and thus are not labeled TREE_ADDRESSABLE. */
830 if (! mf_decl_eligible_p (var) || component_ref_only)
834 base = build1 (ADDR_EXPR,
835 build_pointer_type (TREE_TYPE (var)), var);
841 /* Handle the case of ordinary non-indirection structure
842 accesses. These have only nested COMPONENT_REF nodes (no
843 INDIRECT_REF), but pass through the above filter loop.
844 Note that it's possible for such a struct variable to match
845 the eligible_p test because someone else might take its
848 /* We need special processing for bitfield components, because
849 their addresses cannot be taken. */
852 tree field = TREE_OPERAND (t, 1);
854 if (TREE_CODE (DECL_SIZE_UNIT (field)) == INTEGER_CST)
855 size = DECL_SIZE_UNIT (field);
858 elt = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (elt)),
860 addr = fold_convert (ptr_type_node, elt ? elt : base);
861 addr = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
862 addr, fold_convert (sizetype,
863 byte_position (field)));
866 addr = build1 (ADDR_EXPR, build_pointer_type (type), t);
868 limit = fold_build2 (MINUS_EXPR, mf_uintptr_type,
869 fold_build2 (PLUS_EXPR, mf_uintptr_type,
870 convert (mf_uintptr_type, addr),
877 addr = TREE_OPERAND (t, 0);
879 limit = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
880 fold_build2 (POINTER_PLUS_EXPR, ptr_type_node, base,
886 addr = tree_mem_ref_addr (ptr_type_node, t);
888 limit = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
889 fold_build2 (POINTER_PLUS_EXPR, ptr_type_node, base,
894 case ARRAY_RANGE_REF:
895 warning (OPT_Wmudflap,
896 "mudflap checking not yet implemented for ARRAY_RANGE_REF");
900 /* ??? merge with COMPONENT_REF code above? */
904 /* If we're not dereferencing something, then the access
906 if (TREE_CODE (TREE_OPERAND (t, 0)) != INDIRECT_REF)
909 bpu = bitsize_int (BITS_PER_UNIT);
910 ofs = convert (bitsizetype, TREE_OPERAND (t, 2));
911 rem = size_binop (TRUNC_MOD_EXPR, ofs, bpu);
912 ofs = fold_convert (sizetype, size_binop (TRUNC_DIV_EXPR, ofs, bpu));
914 size = convert (bitsizetype, TREE_OPERAND (t, 1));
915 size = size_binop (PLUS_EXPR, size, rem);
916 size = size_binop (CEIL_DIV_EXPR, size, bpu);
917 size = convert (sizetype, size);
919 addr = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
920 addr = convert (ptr_type_node, addr);
921 addr = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node, addr, ofs);
924 limit = fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
925 fold_build2 (POINTER_PLUS_EXPR, ptr_type_node,
935 mf_build_check_statement_for (base, limit, iter, location, dirflag);
939 mf_xform_derefs (void)
941 basic_block bb, next;
942 gimple_stmt_iterator i;
943 int saved_last_basic_block = last_basic_block;
944 enum gimple_rhs_class grhs_class;
946 bb = ENTRY_BLOCK_PTR ->next_bb;
950 for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i))
952 gimple s = gsi_stmt (i);
954 /* Only a few GIMPLE statements can reference memory. */
955 switch (gimple_code (s))
958 mf_xform_derefs_1 (&i, gimple_assign_lhs_ptr (s),
959 gimple_location (s), integer_one_node);
960 mf_xform_derefs_1 (&i, gimple_assign_rhs1_ptr (s),
961 gimple_location (s), integer_zero_node);
962 grhs_class = get_gimple_rhs_class (gimple_assign_rhs_code (s));
963 if (grhs_class == GIMPLE_BINARY_RHS)
964 mf_xform_derefs_1 (&i, gimple_assign_rhs2_ptr (s),
965 gimple_location (s), integer_zero_node);
969 if (gimple_return_retval (s) != NULL_TREE)
971 mf_xform_derefs_1 (&i, gimple_return_retval_ptr (s),
983 while (bb && bb->index <= saved_last_basic_block);
986 /* ------------------------------------------------------------------------ */
987 /* ADDR_EXPR transforms. Perform the declaration-related mudflap tree
988 transforms on the current function.
990 This is the first part of the mudflap instrumentation. It works on
991 high-level GIMPLE because after lowering, all variables are moved out
992 of their BIND_EXPR binding context, and we lose liveness information
993 for the declarations we wish to instrument. */
996 execute_mudflap_function_decls (void)
998 struct gimplify_ctx gctx;
1000 /* Don't instrument functions such as the synthetic constructor
1001 built during mudflap_finish_file. */
1002 if (mf_marked_p (current_function_decl) ||
1003 DECL_ARTIFICIAL (current_function_decl))
1006 push_gimplify_context (&gctx);
1008 mf_xform_decls (gimple_body (current_function_decl),
1009 DECL_ARGUMENTS (current_function_decl));
1011 pop_gimplify_context (NULL);
1015 /* This struct is passed between mf_xform_decls to store state needed
1016 during the traversal searching for objects that have their
1018 struct mf_xform_decls_data
1024 /* Synthesize a CALL_EXPR and a TRY_FINALLY_EXPR, for this chain of
1025 _DECLs if appropriate. Arrange to call the __mf_register function
1026 now, and the __mf_unregister function later for each. Return the
1027 gimple sequence after synthesis. */
1029 mx_register_decls (tree decl, gimple_seq seq, location_t location)
1031 gimple_seq finally_stmts = NULL;
1032 gimple_stmt_iterator initially_stmts = gsi_start (seq);
1034 while (decl != NULL_TREE)
1036 if (mf_decl_eligible_p (decl)
1037 /* Not already processed. */
1038 && ! mf_marked_p (decl)
1039 /* Automatic variable. */
1040 && ! DECL_EXTERNAL (decl)
1041 && ! TREE_STATIC (decl))
1043 tree size = NULL_TREE, variable_name;
1044 gimple unregister_fncall, register_fncall;
1045 tree unregister_fncall_param, register_fncall_param;
1047 /* Variable-sized objects should have sizes already been
1048 gimplified when we got here. */
1049 size = convert (size_type_node, TYPE_SIZE_UNIT (TREE_TYPE (decl)));
1050 gcc_assert (is_gimple_val (size));
1053 unregister_fncall_param =
1054 mf_mark (build1 (ADDR_EXPR,
1055 build_pointer_type (TREE_TYPE (decl)),
1057 /* __mf_unregister (&VARIABLE, sizeof (VARIABLE), __MF_TYPE_STACK) */
1058 unregister_fncall = gimple_build_call (mf_unregister_fndecl, 3,
1059 unregister_fncall_param,
1061 build_int_cst (NULL_TREE, 3));
1064 variable_name = mf_varname_tree (decl);
1065 register_fncall_param =
1066 mf_mark (build1 (ADDR_EXPR,
1067 build_pointer_type (TREE_TYPE (decl)),
1069 /* __mf_register (&VARIABLE, sizeof (VARIABLE), __MF_TYPE_STACK,
1071 register_fncall = gimple_build_call (mf_register_fndecl, 4,
1072 register_fncall_param,
1074 build_int_cst (NULL_TREE, 3),
1078 /* Accumulate the two calls. */
1079 gimple_set_location (register_fncall, location);
1080 gimple_set_location (unregister_fncall, location);
1082 /* Add the __mf_register call at the current appending point. */
1083 if (gsi_end_p (initially_stmts))
1085 if (!DECL_ARTIFICIAL (decl))
1086 warning (OPT_Wmudflap,
1087 "mudflap cannot track %qE in stub function",
1092 gsi_insert_before (&initially_stmts, register_fncall,
1095 /* Accumulate the FINALLY piece. */
1096 gimple_seq_add_stmt (&finally_stmts, unregister_fncall);
1101 decl = TREE_CHAIN (decl);
1104 /* Actually, (initially_stmts!=NULL) <=> (finally_stmts!=NULL) */
1105 if (finally_stmts != NULL)
1107 gimple stmt = gimple_build_try (seq, finally_stmts, GIMPLE_TRY_FINALLY);
1108 gimple_seq new_seq = gimple_seq_alloc ();
1110 gimple_seq_add_stmt (&new_seq, stmt);
1118 /* Process every variable mentioned in BIND_EXPRs. */
1120 mx_xfn_xform_decls (gimple_stmt_iterator *gsi,
1121 bool *handled_operands_p ATTRIBUTE_UNUSED,
1122 struct walk_stmt_info *wi)
1124 struct mf_xform_decls_data *d = (struct mf_xform_decls_data *) wi->info;
1125 gimple stmt = gsi_stmt (*gsi);
1127 switch (gimple_code (stmt))
1131 /* Process function parameters now (but only once). */
1134 gimple_bind_set_body (stmt,
1135 mx_register_decls (d->param_decls,
1136 gimple_bind_body (stmt),
1137 gimple_location (stmt)));
1138 d->param_decls = NULL_TREE;
1141 gimple_bind_set_body (stmt,
1142 mx_register_decls (gimple_bind_vars (stmt),
1143 gimple_bind_body (stmt),
1144 gimple_location (stmt)));
1155 /* Perform the object lifetime tracking mudflap transform on the given function
1156 tree. The tree is mutated in place, with possibly copied subtree nodes.
1158 For every auto variable declared, if its address is ever taken
1159 within the function, then supply its lifetime to the mudflap
1160 runtime with the __mf_register and __mf_unregister calls.
1164 mf_xform_decls (gimple_seq fnbody, tree fnparams)
1166 struct mf_xform_decls_data d;
1167 struct walk_stmt_info wi;
1168 struct pointer_set_t *pset = pointer_set_create ();
1170 d.param_decls = fnparams;
1171 memset (&wi, 0, sizeof (wi));
1172 wi.info = (void*) &d;
1174 walk_gimple_seq (fnbody, mx_xfn_xform_decls, NULL, &wi);
1175 pointer_set_destroy (pset);
1179 /* ------------------------------------------------------------------------ */
1180 /* Externally visible mudflap functions. */
1183 /* Mark and return the given tree node to prevent further mudflap
1185 static GTY ((param_is (union tree_node))) htab_t marked_trees = NULL;
1192 if (marked_trees == NULL)
1193 marked_trees = htab_create_ggc (31, htab_hash_pointer, htab_eq_pointer,
1196 slot = htab_find_slot (marked_trees, t, INSERT);
1202 mf_marked_p (tree t)
1206 if (marked_trees == NULL)
1209 entry = htab_find (marked_trees, t);
1210 return (entry != NULL);
1213 /* Remember given node as a static of some kind: global data,
1214 function-scope static, or an anonymous constant. Its assembler
1217 /* A list of globals whose incomplete declarations we encountered.
1218 Instead of emitting the __mf_register call for them here, it's
1219 delayed until program finish time. If they're still incomplete by
1220 then, warnings are emitted. */
1222 static GTY (()) VEC(tree,gc) *deferred_static_decls;
1224 /* A list of statements for calling __mf_register() at startup time. */
1225 static GTY (()) tree enqueued_call_stmt_chain;
1228 mudflap_register_call (tree obj, tree object_size, tree varname)
1230 tree arg, call_stmt;
1232 arg = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (obj)), obj);
1233 arg = convert (ptr_type_node, arg);
1235 call_stmt = build_call_expr (mf_register_fndecl, 4,
1237 convert (size_type_node, object_size),
1238 /* __MF_TYPE_STATIC */
1239 build_int_cst (NULL_TREE, 4),
1242 append_to_statement_list (call_stmt, &enqueued_call_stmt_chain);
1246 mudflap_enqueue_decl (tree obj)
1248 if (mf_marked_p (obj))
1251 /* We don't need to process variable decls that are internally
1252 generated extern. If we did, we'd end up with warnings for them
1253 during mudflap_finish_file (). That would confuse the user,
1254 since the text would refer to variables that don't show up in the
1255 user's source code. */
1256 if (DECL_P (obj) && DECL_EXTERNAL (obj) && DECL_ARTIFICIAL (obj))
1259 VEC_safe_push (tree, gc, deferred_static_decls, obj);
1264 mudflap_enqueue_constant (tree obj)
1266 tree object_size, varname;
1268 if (mf_marked_p (obj))
1271 if (TREE_CODE (obj) == STRING_CST)
1272 object_size = build_int_cst (NULL_TREE, TREE_STRING_LENGTH (obj));
1274 object_size = size_in_bytes (TREE_TYPE (obj));
1276 if (TREE_CODE (obj) == STRING_CST)
1277 varname = mf_build_string ("string literal");
1279 varname = mf_build_string ("constant");
1281 mudflap_register_call (obj, object_size, varname);
1285 /* Emit any file-wide instrumentation. */
1287 mudflap_finish_file (void)
1289 tree ctor_statements = NULL_TREE;
1291 /* No need to continue when there were errors. */
1292 if (errorcount != 0 || sorrycount != 0)
1295 /* Insert a call to __mf_init. */
1297 tree call2_stmt = build_call_expr (mf_init_fndecl, 0);
1298 append_to_statement_list (call2_stmt, &ctor_statements);
1301 /* If appropriate, call __mf_set_options to pass along read-ignore mode. */
1302 if (flag_mudflap_ignore_reads)
1304 tree arg = mf_build_string ("-ignore-reads");
1305 tree call_stmt = build_call_expr (mf_set_options_fndecl, 1, arg);
1306 append_to_statement_list (call_stmt, &ctor_statements);
1309 /* Process all enqueued object decls. */
1310 if (deferred_static_decls)
1314 for (i = 0; VEC_iterate (tree, deferred_static_decls, i, obj); i++)
1316 gcc_assert (DECL_P (obj));
1318 if (mf_marked_p (obj))
1321 /* Omit registration for static unaddressed objects. NB:
1322 Perform registration for non-static objects regardless of
1323 TREE_USED or TREE_ADDRESSABLE, because they may be used
1324 from other compilation units. */
1325 if (! TREE_PUBLIC (obj) && ! TREE_ADDRESSABLE (obj))
1328 if (! COMPLETE_TYPE_P (TREE_TYPE (obj)))
1330 warning (OPT_Wmudflap,
1331 "mudflap cannot track unknown size extern %qE",
1336 mudflap_register_call (obj,
1337 size_in_bytes (TREE_TYPE (obj)),
1338 mf_varname_tree (obj));
1341 VEC_truncate (tree, deferred_static_decls, 0);
1344 /* Append all the enqueued registration calls. */
1345 if (enqueued_call_stmt_chain)
1347 append_to_statement_list (enqueued_call_stmt_chain, &ctor_statements);
1348 enqueued_call_stmt_chain = NULL_TREE;
1351 cgraph_build_static_cdtor ('I', ctor_statements,
1352 MAX_RESERVED_INIT_PRIORITY-1);
1359 return flag_mudflap != 0;
1362 struct gimple_opt_pass pass_mudflap_1 =
1366 "mudflap1", /* name */
1367 gate_mudflap, /* gate */
1368 execute_mudflap_function_decls, /* execute */
1371 0, /* static_pass_number */
1372 TV_NONE, /* tv_id */
1373 PROP_gimple_any, /* properties_required */
1374 0, /* properties_provided */
1375 0, /* properties_destroyed */
1376 0, /* todo_flags_start */
1377 TODO_dump_func /* todo_flags_finish */
1381 struct gimple_opt_pass pass_mudflap_2 =
1385 "mudflap2", /* name */
1386 gate_mudflap, /* gate */
1387 execute_mudflap_function_ops, /* execute */
1390 0, /* static_pass_number */
1391 TV_NONE, /* tv_id */
1392 PROP_ssa | PROP_cfg | PROP_gimple_leh,/* properties_required */
1393 0, /* properties_provided */
1394 0, /* properties_destroyed */
1395 0, /* todo_flags_start */
1396 TODO_verify_flow | TODO_verify_stmts
1397 | TODO_dump_func | TODO_update_ssa /* todo_flags_finish */
1401 #include "gt-tree-mudflap.h"