2 * mono-basic-block.c: Routines for parsing basic blocks from the IL stream
5 * Rodrigo Kumpera (rkumpera@novell.com)
7 * Copyright 2010 Novell, Inc (http://www.novell.com)
12 #include <mono/metadata/debug-helpers.h>
13 #include <mono/metadata/metadata-internals.h>
14 #include <mono/metadata/mono-endian.h>
15 #include <mono/metadata/mono-basic-block.h>
16 #include <mono/metadata/opcodes.h>
18 #include <mono/utils/mono-error-internals.h>
19 #include <mono/utils/mono-compiler.h>
21 #define CHECK_ADD4_OVERFLOW_UN(a, b) ((guint32)(0xFFFFFFFFU) - (guint32)(b) < (guint32)(a))
22 #define CHECK_ADD8_OVERFLOW_UN(a, b) ((guint64)(0xFFFFFFFFFFFFFFFFUL) - (guint64)(b) < (guint64)(a))
24 #if SIZEOF_VOID_P == 4
25 #define CHECK_ADDP_OVERFLOW_UN(a,b) CHECK_ADD4_OVERFLOW_UN(a, b)
27 #define CHECK_ADDP_OVERFLOW_UN(a,b) CHECK_ADD8_OVERFLOW_UN(a, b)
30 #define ADDP_IS_GREATER_OR_OVF(a, b, c) (((a) + (b) > (c)) || CHECK_ADDP_OVERFLOW_UN (a, b))
31 #define ADD_IS_GREATER_OR_OVF(a, b, c) (((a) + (b) > (c)) || CHECK_ADD4_OVERFLOW_UN (a, b))
43 dump_bb_list (MonoSimpleBasicBlock *bb, MonoSimpleBasicBlock **root, const char *msg)
45 printf ("------- %s --- root is %x ---\n", msg, (*root)->start);
48 printf ("BB start %x end %x left ", bb->start, bb->end);
50 printf ("%x", bb->left->start);
56 printf ("%x", bb->right->start);
62 printf ("%x", bb->parent->start);
66 printf(" color %s out [", bb->colour == RED ? "red" : "black");
68 for (tmp = bb->out_bb; tmp; tmp = tmp->next) {
69 MonoSimpleBasicBlock *to = tmp->data;
70 printf ("%x ", to->start);
72 printf ("] %s\n", bb->dead ? "dead" : "alive");
80 bb_unlink (MonoSimpleBasicBlock *from, MonoSimpleBasicBlock *to)
83 from->out_bb = g_slist_remove (from->out_bb, to);
87 bb_link (MonoSimpleBasicBlock *from, MonoSimpleBasicBlock *to)
89 if (g_slist_find (from->out_bb, to))
91 from->out_bb = g_slist_prepend (from->out_bb, to);
95 static MonoSimpleBasicBlock*
96 bb_grandparent (MonoSimpleBasicBlock *bb)
98 return bb && bb->parent ? bb->parent->parent : NULL;
101 static MonoSimpleBasicBlock*
102 bb_uncle (MonoSimpleBasicBlock *bb)
104 MonoSimpleBasicBlock *gp = bb_grandparent (bb);
107 if (bb->parent == gp->left)
113 change_node (MonoSimpleBasicBlock *from, MonoSimpleBasicBlock *to, MonoSimpleBasicBlock **root)
115 MonoSimpleBasicBlock *parent = from->parent;
117 if (parent->left == from)
128 rotate_right (MonoSimpleBasicBlock *parent, MonoSimpleBasicBlock **root)
130 MonoSimpleBasicBlock *bb = parent->left;
132 parent->left = bb->right;
133 parent->left->parent = parent;
137 change_node (parent, bb, root);
142 rotate_left (MonoSimpleBasicBlock *bb, MonoSimpleBasicBlock **root)
144 MonoSimpleBasicBlock *other = bb->right;
146 bb->right = other->left;
147 bb->right->parent = bb;
151 change_node (bb, other, root);
155 /* School book implementation of a RB tree with insert then fix (which requires a parent pointer)
156 * TODO implement Sedgewick's version that doesn't require parent pointers
159 bb_insert (MonoSimpleBasicBlock *first, MonoSimpleBasicBlock *bb, MonoSimpleBasicBlock **root)
161 MonoSimpleBasicBlock *parent, *uncle, *grandparent;
162 int bb_start = bb->start;
166 if (bb_start < parent->start) {
167 if (parent->left == NULL) {
171 parent = parent->left;
173 if (parent->right == NULL) {
177 parent = parent->right;
186 if (bb->parent == NULL) {
191 if (bb->parent->colour == BLACK)
194 uncle = bb_uncle (bb);
195 if (uncle && uncle->colour == RED) {
196 grandparent = bb_grandparent (bb);
198 bb->parent->colour = BLACK;
199 uncle->colour = BLACK;
200 grandparent->colour = RED;
205 grandparent = bb_grandparent (bb);
206 if ((bb == bb->parent->right) && (bb->parent == grandparent->left)) {
207 rotate_left (bb->parent, root);
209 } else if ((bb == bb->parent->left) && (bb->parent == grandparent->right)) {
210 rotate_right (bb->parent, root);
214 grandparent = bb_grandparent (bb);
215 bb->parent->colour = BLACK;
216 grandparent->colour = RED;
217 if ((bb == bb->parent->left) && (bb->parent == grandparent->left))
218 rotate_right (grandparent, root);
220 rotate_left (grandparent, root);
226 bb_idx_is_contained (MonoSimpleBasicBlock *bb, int target)
228 return bb->start <= target && target < bb->end;
232 * Split the basic blocks from @first at @target.
233 * @hint is a guess of a very close to the target basic block. It is probed before the RB tree as it's often possible
234 * to provide a near to exact guess (next block splits, switch branch targets, etc)
237 static MonoSimpleBasicBlock*
238 bb_split (MonoSimpleBasicBlock *first, MonoSimpleBasicBlock *hint, MonoSimpleBasicBlock **root, guint target, gboolean link_blocks, MonoMethod *method, MonoError *error)
240 MonoSimpleBasicBlock *res, *bb = first;
242 if (bb_idx_is_contained (hint, target)) {
244 } else if (hint->next && bb_idx_is_contained (hint->next, target)) {
249 if (bb_idx_is_contained (first, target))
251 if (first->start > target)
254 first = first->right;
259 mono_error_set_not_verifiable (error, method, "Invalid instruction target %x", target);
263 if (first->start == target)
266 res = g_new0 (MonoSimpleBasicBlock, 1);
268 res->end = first->end;
269 res->next = first->next;
270 res->out_bb = first->out_bb;
273 first->end = res->start;
275 first->out_bb = NULL;
278 bb_link (first, res);
279 bb_insert (bb, res, root);
285 bb_liveness (MonoSimpleBasicBlock *bb)
287 GPtrArray* mark_stack = g_ptr_array_new ();
290 /*All function entry points (prologue, EH handler/filter) are already marked*/
293 g_ptr_array_add (mark_stack, bb);
297 while (mark_stack->len > 0) {
298 MonoSimpleBasicBlock *block = g_ptr_array_remove_index_fast (mark_stack, mark_stack->len - 1);
301 for (tmp = block->out_bb; tmp; tmp = tmp->next) {
302 MonoSimpleBasicBlock *to = tmp->data;
304 g_ptr_array_add (mark_stack, to);
308 g_ptr_array_free (mark_stack, TRUE);
311 /*This doesn't returns endfilter because it's not useful to split at its boundary.
312 Endfilter must be the last instruction of a filter clause and MS enforces this, so we can't have
316 mono_opcode_has_static_branch (int opcode)
321 case MONO_CEE_RETHROW:
322 case MONO_CEE_ENDFINALLY:
330 bb_formation_il_pass (const unsigned char *start, const unsigned char *end, MonoSimpleBasicBlock *bb, MonoSimpleBasicBlock **root, MonoMethod *method, MonoError *error)
332 unsigned const char *ip = start;
334 guint cli_addr, offset;
335 MonoSimpleBasicBlock *branch, *next, *current;
336 const MonoOpcode *opcode;
341 cli_addr = ip - start;
342 size = mono_opcode_value_and_size (&ip, end, &value);
344 mono_error_set_not_verifiable (error, method, "Invalid instruction %x", *ip);
348 while (current && cli_addr >= current->end)
349 current = current->next;
352 opcode = &mono_opcodes [value];
353 switch (opcode->argument) {
356 if (!mono_opcode_has_static_branch (value) || ip >= end)
358 if (!(next = bb_split (bb, current, root, ip - start, FALSE, method, error)))
361 bb_unlink (current, next);
364 case MonoInlineString:
366 case MonoInlineField:
369 case MonoShortInlineR:
374 case MonoInlineMethod:
376 if (value != MONO_CEE_JMP || ip >= end)
378 if (!(next = bb_split (bb, current, root, ip - start, FALSE, method, error)))
381 bb_unlink (current, next);
388 case MonoShortInlineVar:
389 case MonoShortInlineI:
396 case MonoShortInlineBrTarget:
397 case MonoInlineBrTarget:
398 if (opcode->argument == MonoShortInlineBrTarget) {
399 offset = cli_addr + 2 + (signed char)ip [1];
402 offset = cli_addr + 5 + (gint32)read32 (ip + 1);
406 branch = bb_split (bb, current, root, offset, TRUE, method, error);
410 /*If we splitted the current BB*/
411 if (offset < cli_addr && branch->start > current->start)
414 next = bb_split (bb, current, root, ip - start, opcode->flow_type != MONO_FLOW_BRANCH, method, error);
421 bb_link (current, branch);
422 if (next && opcode->flow_type == MONO_FLOW_BRANCH && next != branch) {
423 bb_unlink (current, next);
427 case MonoInlineSwitch: {
428 MonoSimpleBasicBlock *tmp;
429 guint32 j, n = read32 (ip + 1);
432 offset = cli_addr + 5 + 4 * n;
433 if (!(next = bb_split (bb, current, root, offset, TRUE, method, error)))
436 bb_link (current, next);
439 for (j = 0; j < n; ++j) {
441 mono_error_set_not_verifiable (error, method, "Invalid switch instruction %x", cli_addr);
444 if (!(next = bb_split (bb, next, root, offset + (gint32)read32 (ip), TRUE, method, error)))
446 bb_link (current, next);
453 mono_error_set_not_verifiable (error, method, "Invalid instruction %x", *ip);
458 mono_error_set_not_verifiable (error, method, "Invalid last instruction");
462 bb_formation_eh_pass (MonoMethodHeader *header, MonoSimpleBasicBlock *bb, MonoSimpleBasicBlock **root, MonoMethod *method, MonoError *error)
465 int end = header->code_size;
466 /*We must split at all points to verify for targets in the middle of an instruction*/
467 for (i = 0; i < header->num_clauses; ++i) {
468 MonoExceptionClause *clause = header->clauses + i;
469 MonoSimpleBasicBlock *try_block, *handler;
471 if (!(try_block = bb_split (bb, bb, root, clause->try_offset, TRUE, method, error)))
474 handler = bb_split (bb, try_block, root, clause->handler_offset, FALSE, method, error);
477 handler->dead = FALSE;
479 if (clause->flags == MONO_EXCEPTION_CLAUSE_FILTER) {
480 MonoSimpleBasicBlock *filter = bb_split (bb, try_block, root, clause->data.filter_offset, FALSE, method, error);
483 filter->dead = FALSE;
486 if (clause->try_offset + clause->try_len < end && !bb_split (bb, try_block, root, clause->try_offset + clause->try_len, FALSE, method, error))
489 if (clause->handler_offset + clause->handler_len < end && !bb_split (bb, handler, root, clause->handler_offset + clause->handler_len, FALSE, method, error))
495 * mono_basic_block_free:
497 * Release the memory associated with the list of basis blocks @bb.
500 mono_basic_block_free (MonoSimpleBasicBlock *bb)
503 MonoSimpleBasicBlock *next = bb->next;
505 g_slist_free (bb->out_bb);
512 * mono_basic_block_split:
514 * Return the list of basic blocks of method. Return NULL on failure and set @error.
516 MonoSimpleBasicBlock*
517 mono_basic_block_split (MonoMethod *method, MonoError *error)
519 MonoSimpleBasicBlock *bb, *root;
520 const unsigned char *start, *end;
521 MonoMethodHeader *header = mono_method_get_header (method);
522 start = header->code;
523 end = start + header->code_size;
525 mono_error_init (error);
528 mono_error_set_not_verifiable (error, method, "Could not decode header");
532 bb = g_new0 (MonoSimpleBasicBlock, 1);
534 bb->end = end - start;
539 bb_formation_il_pass (start, end, bb, &root, method, error);
540 if (!mono_error_ok (error))
543 bb_formation_eh_pass (header, bb, &root, method, error);
544 if (!mono_error_ok (error))
550 dump_bb_list (bb, &root, g_strdup_printf("AFTER LIVENESS %s", mono_method_full_name (method, TRUE)));
553 mono_metadata_free_mh (header);
557 mono_metadata_free_mh (header);
558 mono_basic_block_free (bb);
563 * mono_opcode_value_and_size:
565 * Returns the size of the opcode starting at *@ip, or -1 on error.
566 * Value is the opcode number.
569 mono_opcode_value_and_size (const unsigned char **ip, const unsigned char *end, int *value)
571 const unsigned char *start = *ip, *p;
572 int i = *value = mono_opcode_value (ip, end);
574 if (i < 0 || i >= MONO_CEE_LAST)
578 switch (mono_opcodes [i].argument) {
582 case MonoInlineString:
584 case MonoInlineField:
585 case MonoInlineMethod:
588 case MonoShortInlineR:
590 case MonoInlineBrTarget:
596 case MonoShortInlineVar:
597 case MonoShortInlineI:
598 case MonoShortInlineBrTarget:
605 case MonoInlineSwitch: {
607 if (ADDP_IS_GREATER_OR_OVF (p, 5, end))
609 entries = read32 (p + 1);
610 if (entries >= (0xFFFFFFFFU / 4))
612 size = 4 + 4 * entries;
616 g_error ("Invalid opcode %d argument %d max opcode %d\n", i, mono_opcodes [i].argument, MONO_CEE_LAST);
619 if (ADDP_IS_GREATER_OR_OVF (p, size, end))
622 return (p - start) + size;
628 * Returns the size of the opcode starting at @ip, or -1 on error.
631 mono_opcode_size (const unsigned char *ip, const unsigned char *end)
634 return mono_opcode_value_and_size (&ip, end, &tmp);