2 * unwind.c: Stack Unwinding Interface
5 * Zoltan Varga (vargaz@gmail.com)
7 * (C) 2008 Novell, Inc.
11 #include "mini-unwind.h"
13 #include <mono/utils/mono-counters.h>
14 #include <mono/utils/freebsd-dwarf.h>
15 #include <mono/utils/hazard-pointer.h>
16 #include <mono/metadata/threads-types.h>
17 #include <mono/metadata/mono-endian.h>
31 guint8 info [MONO_ZERO_LEN_ARRAY];
34 #define ALIGN_TO(val,align) ((((size_t)val) + ((align) - 1)) & ~((align) - 1))
36 static mono_mutex_t unwind_mutex;
38 static MonoUnwindInfo **cached_info;
39 static int cached_info_next, cached_info_size;
40 static GSList *cached_info_list;
42 static int unwind_info_size;
44 #define unwind_lock() mono_os_mutex_lock (&unwind_mutex)
45 #define unwind_unlock() mono_os_mutex_unlock (&unwind_mutex)
48 static int map_hw_reg_to_dwarf_reg [] = { 0, 2, 1, 3, 7, 6, 4, 5, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
49 #define NUM_REGS AMD64_NREG
50 #define DWARF_DATA_ALIGN (-8)
51 #define DWARF_PC_REG (mono_hw_reg_to_dwarf_reg (AMD64_RIP))
52 #elif defined(TARGET_ARM)
53 // http://infocenter.arm.com/help/topic/com.arm.doc.ihi0040a/IHI0040A_aadwarf.pdf
54 /* Assign d8..d15 to hregs 16..24 (dwarf regs 264..271) */
55 static int map_hw_reg_to_dwarf_reg [] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 264, 265, 266, 267, 268, 269, 270, 271 };
57 #define DWARF_DATA_ALIGN (-4)
58 #define DWARF_PC_REG (mono_hw_reg_to_dwarf_reg (ARMREG_LR))
59 #define IS_DOUBLE_REG(dwarf_reg) (((dwarf_reg) >= 264) && ((dwarf_reg) <= 271))
60 #elif defined(TARGET_ARM64)
62 #define DWARF_DATA_ALIGN (-8)
64 #define DWARF_PC_REG 30
65 static int map_hw_reg_to_dwarf_reg [] = {
66 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
67 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
69 72, 73, 74, 75, 76, 77, 78, 79,
71 #elif defined (TARGET_X86)
73 * ebp and esp are swapped:
74 * http://lists.cs.uiuc.edu/pipermail/lldb-dev/2014-January/003101.html
76 static int map_hw_reg_to_dwarf_reg [] = { 0, 1, 2, 3, 5, 4, 6, 7, 8 };
78 #define NUM_REGS X86_NREG + 1
79 #define DWARF_DATA_ALIGN (-4)
80 #define DWARF_PC_REG (mono_hw_reg_to_dwarf_reg (X86_NREG))
81 #elif defined (TARGET_POWERPC)
82 // http://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi-1.9.html
83 static int map_hw_reg_to_dwarf_reg [] = { 0, 1, 2, 3, 4, 5, 6, 7, 8,
84 9, 10, 11, 12, 13, 14, 15, 16,
85 17, 18, 19, 20, 21, 22, 23, 24,
86 25, 26, 27, 28, 29, 30, 31 };
88 #define DWARF_DATA_ALIGN (-(gint32)sizeof (mgreg_t))
89 #define DWARF_PC_REG 108
90 #elif defined (TARGET_S390X)
91 static int map_hw_reg_to_dwarf_reg [] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
93 #define DWARF_DATA_ALIGN (-8)
94 #define DWARF_PC_REG (mono_hw_reg_to_dwarf_reg (14))
95 #elif defined (TARGET_MIPS)
97 static int map_hw_reg_to_dwarf_reg [32] = {
98 0, 1, 2, 3, 4, 5, 6, 7,
99 8, 9, 10, 11, 12, 13, 14, 15,
100 16, 17, 18, 19, 20, 21, 22, 23,
101 24, 25, 26, 27, 28, 29, 30, 31
104 #define DWARF_DATA_ALIGN (-(gint32)sizeof (mgreg_t))
105 #define DWARF_PC_REG (mono_hw_reg_to_dwarf_reg (mips_ra))
107 static int map_hw_reg_to_dwarf_reg [16];
109 #define DWARF_DATA_ALIGN 0
110 #define DWARF_PC_REG -1
113 #ifndef IS_DOUBLE_REG
114 #define IS_DOUBLE_REG(dwarf_reg) 0
117 static gboolean dwarf_reg_to_hw_reg_inited;
119 static int map_dwarf_reg_to_hw_reg [NUM_REGS];
122 * mono_hw_reg_to_dwarf_reg:
124 * Map the hardware register number REG to the register number used by DWARF.
127 mono_hw_reg_to_dwarf_reg (int reg)
129 #ifdef TARGET_POWERPC
133 g_assert (reg < NUM_REGS);
137 g_assert_not_reached ();
140 return map_hw_reg_to_dwarf_reg [reg];
149 g_assert (NUM_REGS > 0);
150 for (i = 0; i < sizeof (map_hw_reg_to_dwarf_reg) / sizeof (int); ++i) {
151 map_dwarf_reg_to_hw_reg [mono_hw_reg_to_dwarf_reg (i)] = i;
154 #ifdef TARGET_POWERPC
155 map_dwarf_reg_to_hw_reg [DWARF_PC_REG] = ppc_lr;
158 mono_memory_barrier ();
159 dwarf_reg_to_hw_reg_inited = TRUE;
163 mono_dwarf_reg_to_hw_reg (int reg)
165 if (!dwarf_reg_to_hw_reg_inited)
168 return map_dwarf_reg_to_hw_reg [reg];
171 static G_GNUC_UNUSED void
172 encode_uleb128 (guint32 value, guint8 *buf, guint8 **endbuf)
177 guint8 b = value & 0x7f;
179 if (value != 0) /* more bytes to come */
187 static G_GNUC_UNUSED void
188 encode_sleb128 (gint32 value, guint8 *buf, guint8 **endbuf)
191 gboolean negative = (value < 0);
199 /* the following is unnecessary if the
200 * implementation of >>= uses an arithmetic rather
201 * than logical shift for a signed left operand
205 value |= - (1 <<(size - 7));
206 /* sign bit of byte is second high order bit (0x40) */
207 if ((value == 0 && !(byte & 0x40)) ||
208 (value == -1 && (byte & 0x40)))
218 static inline guint32
219 decode_uleb128 (guint8 *buf, guint8 **endbuf)
229 res = res | (((int)(b & 0x7f)) << shift);
241 decode_sleb128 (guint8 *buf, guint8 **endbuf)
251 res = res | (((int)(b & 0x7f)) << shift);
254 if (shift < 32 && (b & 0x40))
255 res |= - (1 << shift);
266 mono_print_unwind_info (guint8 *unwind_info, int unwind_info_len)
269 int pos, reg, offset, cfa_reg, cfa_offset;
273 while (p < unwind_info + unwind_info_len) {
277 case DW_CFA_advance_loc:
284 offset = decode_uleb128 (p, &p) * DWARF_DATA_ALIGN;
285 if (reg == DWARF_PC_REG)
286 printf ("CFA: [%x] offset: %s at cfa-0x%x\n", pos, "pc", -offset);
288 printf ("CFA: [%x] offset: %s at cfa-0x%x\n", pos, mono_arch_regname (mono_dwarf_reg_to_hw_reg (reg)), -offset);
295 cfa_reg = decode_uleb128 (p, &p);
296 cfa_offset = decode_uleb128 (p, &p);
297 printf ("CFA: [%x] def_cfa: %s+0x%x\n", pos, mono_arch_regname (mono_dwarf_reg_to_hw_reg (cfa_reg)), cfa_offset);
299 case DW_CFA_def_cfa_offset:
300 cfa_offset = decode_uleb128 (p, &p);
301 printf ("CFA: [%x] def_cfa_offset: 0x%x\n", pos, cfa_offset);
303 case DW_CFA_def_cfa_register:
304 cfa_reg = decode_uleb128 (p, &p);
305 printf ("CFA: [%x] def_cfa_reg: %s\n", pos, mono_arch_regname (mono_dwarf_reg_to_hw_reg (cfa_reg)));
307 case DW_CFA_offset_extended_sf:
308 reg = decode_uleb128 (p, &p);
309 offset = decode_sleb128 (p, &p) * DWARF_DATA_ALIGN;
310 printf ("CFA: [%x] offset_extended_sf: %s at cfa-0x%x\n", pos, mono_arch_regname (mono_dwarf_reg_to_hw_reg (reg)), -offset);
312 case DW_CFA_same_value:
313 reg = decode_uleb128 (p, &p);
314 printf ("CFA: [%x] same_value: %s\n", pos, mono_arch_regname (mono_dwarf_reg_to_hw_reg (reg)));
316 case DW_CFA_advance_loc4:
320 case DW_CFA_remember_state:
321 printf ("CFA: [%x] remember_state\n", pos);
323 case DW_CFA_restore_state:
324 printf ("CFA: [%x] restore_state\n", pos);
326 case DW_CFA_mono_advance_loc:
327 printf ("CFA: [%x] mono_advance_loc\n", pos);
330 g_assert_not_reached ();
335 g_assert_not_reached ();
341 * mono_unwind_ops_encode_full:
343 * Encode the unwind ops in UNWIND_OPS into the compact DWARF encoding.
344 * Return a pointer to malloc'ed memory.
345 * If ENABLE_EXTENSIONS is FALSE, avoid encoding the mono extension
346 * opcode (DW_CFA_mono_advance_loc).
349 mono_unwind_ops_encode_full (GSList *unwind_ops, guint32 *out_len, gboolean enable_extensions)
361 for (; l; l = l->next) {
364 op = (MonoUnwindOp *)l->data;
366 /* Convert the register from the hw encoding to the dwarf encoding */
367 reg = mono_hw_reg_to_dwarf_reg (op->reg);
369 if (op->op == DW_CFA_mono_advance_loc) {
370 /* This advances loc to its location */
374 /* Emit an advance_loc if neccesary */
375 while (op->when > loc) {
376 if (op->when - loc > 65536) {
377 *p ++ = DW_CFA_advance_loc4;
378 *(guint32*)p = (guint32)(op->when - loc);
379 g_assert (read32 (p) == (guint32)(op->when - loc));
382 } else if (op->when - loc > 256) {
383 *p ++ = DW_CFA_advance_loc2;
384 *(guint16*)p = (guint16)(op->when - loc);
385 g_assert (read16 (p) == (guint32)(op->when - loc));
388 } else if (op->when - loc >= 32) {
389 *p ++ = DW_CFA_advance_loc1;
390 *(guint8*)p = (guint8)(op->when - loc);
393 } else if (op->when - loc < 32) {
394 *p ++ = DW_CFA_advance_loc | (op->when - loc);
397 *p ++ = DW_CFA_advance_loc | (30);
405 encode_uleb128 (reg, p, &p);
406 encode_uleb128 (op->val, p, &p);
408 case DW_CFA_def_cfa_offset:
410 encode_uleb128 (op->val, p, &p);
412 case DW_CFA_def_cfa_register:
414 encode_uleb128 (reg, p, &p);
416 case DW_CFA_same_value:
418 encode_uleb128 (reg, p, &p);
422 *p ++ = DW_CFA_offset_extended_sf;
423 encode_uleb128 (reg, p, &p);
424 encode_sleb128 (op->val / DWARF_DATA_ALIGN, p, &p);
426 *p ++ = DW_CFA_offset | reg;
427 encode_uleb128 (op->val / DWARF_DATA_ALIGN, p, &p);
430 case DW_CFA_remember_state:
431 case DW_CFA_restore_state:
434 case DW_CFA_mono_advance_loc:
435 if (!enable_extensions)
437 /* Only one location is supported */
438 g_assert (op->val == 0);
442 g_assert_not_reached ();
447 g_assert (p - buf < 4096);
449 res = (guint8 *)g_malloc (p - buf);
450 memcpy (res, buf, p - buf);
455 mono_unwind_ops_encode (GSList *unwind_ops, guint32 *out_len)
457 return mono_unwind_ops_encode_full (unwind_ops, out_len, TRUE);
461 #define UNW_DEBUG(stmt) do { stmt; } while (0)
463 #define UNW_DEBUG(stmt) do { } while (0)
466 static G_GNUC_UNUSED void
467 print_dwarf_state (int cfa_reg, int cfa_offset, int ip, int nregs, Loc *locations, guint8 *reg_saved)
471 printf ("\t%x: cfa=r%d+%d ", ip, cfa_reg, cfa_offset);
473 for (i = 0; i < nregs; ++i)
474 if (reg_saved [i] && locations [i].loc_type == LOC_OFFSET)
475 printf ("r%d@%d(cfa) ", i, locations [i].offset);
480 Loc locations [NUM_REGS];
481 guint8 reg_saved [NUM_REGS];
482 int cfa_reg, cfa_offset;
486 * Given the state of the current frame as stored in REGS, execute the unwind
487 * operations in unwind_info until the location counter reaches POS. The result is
488 * stored back into REGS. OUT_CFA will receive the value of the CFA.
489 * If SAVE_LOCATIONS is non-NULL, it should point to an array of size SAVE_LOCATIONS_LEN.
490 * On return, the nth entry will point to the address of the stack slot where register
491 * N was saved, or NULL, if it was not saved by this frame.
492 * MARK_LOCATIONS should contain the locations marked by mono_emit_unwind_op_mark_loc (), if any.
493 * This function is signal safe.
496 mono_unwind_frame (guint8 *unwind_info, guint32 unwind_info_len,
497 guint8 *start_ip, guint8 *end_ip, guint8 *ip, guint8 **mark_locations,
498 mono_unwind_reg_t *regs, int nregs,
499 mgreg_t **save_locations, int save_locations_len,
502 Loc locations [NUM_REGS];
503 guint8 reg_saved [NUM_REGS];
504 int i, pos, reg, cfa_reg = -1, cfa_offset = 0, offset;
507 UnwindState state_stack [1];
510 memset (reg_saved, 0, sizeof (reg_saved));
511 state_stack [0].cfa_reg = -1;
512 state_stack [0].cfa_offset = 0;
519 while (pos <= ip - start_ip && p < unwind_info + unwind_info_len) {
523 case DW_CFA_advance_loc:
524 UNW_DEBUG (print_dwarf_state (cfa_reg, cfa_offset, pos, nregs, locations));
531 reg_saved [reg] = TRUE;
532 locations [reg].loc_type = LOC_OFFSET;
533 locations [reg].offset = decode_uleb128 (p, &p) * DWARF_DATA_ALIGN;
540 cfa_reg = decode_uleb128 (p, &p);
541 cfa_offset = decode_uleb128 (p, &p);
543 case DW_CFA_def_cfa_offset:
544 cfa_offset = decode_uleb128 (p, &p);
546 case DW_CFA_def_cfa_register:
547 cfa_reg = decode_uleb128 (p, &p);
549 case DW_CFA_offset_extended_sf:
550 reg = decode_uleb128 (p, &p);
551 offset = decode_sleb128 (p, &p);
552 g_assert (reg < NUM_REGS);
553 reg_saved [reg] = TRUE;
554 locations [reg].loc_type = LOC_OFFSET;
555 locations [reg].offset = offset * DWARF_DATA_ALIGN;
557 case DW_CFA_offset_extended:
558 reg = decode_uleb128 (p, &p);
559 offset = decode_uleb128 (p, &p);
560 g_assert (reg < NUM_REGS);
561 reg_saved [reg] = TRUE;
562 locations [reg].loc_type = LOC_OFFSET;
563 locations [reg].offset = offset * DWARF_DATA_ALIGN;
565 case DW_CFA_same_value:
566 reg = decode_uleb128 (p, &p);
567 locations [reg].loc_type = LOC_SAME;
569 case DW_CFA_advance_loc1:
573 case DW_CFA_advance_loc2:
577 case DW_CFA_advance_loc4:
581 case DW_CFA_remember_state:
582 g_assert (state_stack_pos == 0);
583 memcpy (&state_stack [0].locations, &locations, sizeof (locations));
584 memcpy (&state_stack [0].reg_saved, ®_saved, sizeof (reg_saved));
585 state_stack [0].cfa_reg = cfa_reg;
586 state_stack [0].cfa_offset = cfa_offset;
589 case DW_CFA_restore_state:
590 g_assert (state_stack_pos == 1);
592 memcpy (&locations, &state_stack [0].locations, sizeof (locations));
593 memcpy (®_saved, &state_stack [0].reg_saved, sizeof (reg_saved));
594 cfa_reg = state_stack [0].cfa_reg;
595 cfa_offset = state_stack [0].cfa_offset;
597 case DW_CFA_mono_advance_loc:
598 g_assert (mark_locations [0]);
599 pos = mark_locations [0] - start_ip;
602 g_assert_not_reached ();
607 g_assert_not_reached ();
612 memset (save_locations, 0, save_locations_len * sizeof (mgreg_t*));
614 g_assert (cfa_reg != -1);
615 cfa_val = (guint8*)regs [mono_dwarf_reg_to_hw_reg (cfa_reg)] + cfa_offset;
616 for (i = 0; i < NUM_REGS; ++i) {
617 if (reg_saved [i] && locations [i].loc_type == LOC_OFFSET) {
618 int hreg = mono_dwarf_reg_to_hw_reg (i);
619 g_assert (hreg < nregs);
620 if (IS_DOUBLE_REG (i))
621 regs [hreg] = *(guint64*)(cfa_val + locations [i].offset);
623 regs [hreg] = *(mgreg_t*)(cfa_val + locations [i].offset);
624 if (save_locations && hreg < save_locations_len)
625 save_locations [hreg] = (mgreg_t*)(cfa_val + locations [i].offset);
633 mono_unwind_init (void)
635 mono_os_mutex_init_recursive (&unwind_mutex);
637 mono_counters_register ("Unwind info size", MONO_COUNTER_JIT | MONO_COUNTER_INT, &unwind_info_size);
641 mono_unwind_cleanup (void)
645 mono_os_mutex_destroy (&unwind_mutex);
650 for (i = 0; i < cached_info_next; ++i) {
651 MonoUnwindInfo *cached = cached_info [i];
655 g_free (cached_info);
657 for (GSList *cursor = cached_info_list; cursor != NULL; cursor = cursor->next)
658 g_free (cursor->data);
660 g_slist_free (cached_info_list);
664 * mono_cache_unwind_info
666 * Save UNWIND_INFO in the unwind info cache and return an id which can be passed
667 * to mono_get_cached_unwind_info to get a cached copy of the info.
668 * A copy is made of the unwind info.
669 * This function is useful for two reasons:
670 * - many methods have the same unwind info
671 * - MonoJitInfo->unwind_info is an int so it can't store the pointer to the unwind info
674 mono_cache_unwind_info (guint8 *unwind_info, guint32 unwind_info_len)
677 MonoUnwindInfo *info;
681 if (cached_info == NULL) {
682 cached_info_size = 16;
683 cached_info = g_new0 (MonoUnwindInfo*, cached_info_size);
686 for (i = 0; i < cached_info_next; ++i) {
687 MonoUnwindInfo *cached = cached_info [i];
689 if (cached->len == unwind_info_len && memcmp (cached->info, unwind_info, unwind_info_len) == 0) {
695 info = (MonoUnwindInfo *)g_malloc (sizeof (MonoUnwindInfo) + unwind_info_len);
696 info->len = unwind_info_len;
697 memcpy (&info->info, unwind_info, unwind_info_len);
699 i = cached_info_next;
701 if (cached_info_next >= cached_info_size) {
702 MonoUnwindInfo **new_table;
705 * Avoid freeing the old table so mono_get_cached_unwind_info ()
706 * doesn't need locks/hazard pointers.
709 new_table = g_new0 (MonoUnwindInfo*, cached_info_size * 2);
711 memcpy (new_table, cached_info, cached_info_size * sizeof (MonoUnwindInfo*));
713 mono_memory_barrier ();
715 cached_info_list = g_slist_prepend (cached_info_list, cached_info);
717 cached_info = new_table;
719 cached_info_size *= 2;
722 cached_info [cached_info_next ++] = info;
724 unwind_info_size += sizeof (MonoUnwindInfo) + unwind_info_len;
731 * This function is signal safe.
734 mono_get_cached_unwind_info (guint32 index, guint32 *unwind_info_len)
736 MonoUnwindInfo **table;
737 MonoUnwindInfo *info;
741 * This doesn't need any locks/hazard pointers,
742 * since new tables are copies of the old ones.
746 info = table [index];
748 *unwind_info_len = info->len;
755 * mono_unwind_get_dwarf_data_align:
757 * Return the data alignment used by the encoded unwind information.
760 mono_unwind_get_dwarf_data_align (void)
762 return DWARF_DATA_ALIGN;
766 * mono_unwind_get_dwarf_pc_reg:
768 * Return the dwarf register number of the register holding the ip of the
772 mono_unwind_get_dwarf_pc_reg (void)
778 decode_cie_op (guint8 *p, guint8 **endp)
783 case DW_CFA_advance_loc:
788 decode_uleb128 (p, &p);
795 decode_uleb128 (p, &p);
796 decode_uleb128 (p, &p);
798 case DW_CFA_def_cfa_offset:
799 decode_uleb128 (p, &p);
801 case DW_CFA_def_cfa_register:
802 decode_uleb128 (p, &p);
804 case DW_CFA_advance_loc4:
807 case DW_CFA_offset_extended_sf:
808 decode_uleb128 (p, &p);
809 decode_uleb128 (p, &p);
812 g_assert_not_reached ();
817 g_assert_not_reached ();
824 read_encoded_val (guint32 encoding, guint8 *p, guint8 **endp)
828 switch (encoding & 0xf) {
829 case DW_EH_PE_sdata8:
833 case DW_EH_PE_sdata4:
838 g_assert_not_reached ();
848 * Decode the Mono specific Language Specific Data Area generated by LLVM.
851 decode_lsda (guint8 *lsda, guint8 *code, MonoJitExceptionInfo **ex_info, guint32 *ex_info_len, gpointer **type_info, int *this_reg, int *this_offset)
854 int i, ncall_sites, this_encoding;
855 guint32 mono_magic, version;
859 /* This is the modified LSDA generated by the LLVM mono branch */
860 mono_magic = decode_uleb128 (p, &p);
861 g_assert (mono_magic == 0x4d4fef4f);
862 version = decode_uleb128 (p, &p);
863 g_assert (version == 1);
866 if (this_encoding == DW_EH_PE_udata4) {
867 gint32 op, reg, offset;
869 /* 'this' location */
871 g_assert (op == DW_OP_bregx);
873 reg = decode_uleb128 (p, &p);
874 offset = decode_sleb128 (p, &p);
876 *this_reg = mono_dwarf_reg_to_hw_reg (reg);
877 *this_offset = offset;
879 g_assert (this_encoding == DW_EH_PE_omit);
884 ncall_sites = decode_uleb128 (p, &p);
885 p = (guint8*)ALIGN_TO ((mgreg_t)p, 4);
888 *ex_info = (MonoJitExceptionInfo *)g_malloc0 (ncall_sites * sizeof (MonoJitExceptionInfo));
889 *ex_info_len = ncall_sites;
892 *type_info = (gpointer *)g_malloc0 (ncall_sites * sizeof (gpointer));
894 for (i = 0; i < ncall_sites; ++i) {
895 int block_start_offset, block_size, landing_pad;
898 block_start_offset = read32 (p);
899 p += sizeof (gint32);
900 block_size = read32 (p);
901 p += sizeof (gint32);
902 landing_pad = read32 (p);
903 p += sizeof (gint32);
905 p += sizeof (gint32);
907 g_assert (landing_pad);
908 g_assert (((size_t)tinfo % 4) == 0);
909 //printf ("X: %p %d\n", landing_pad, *(int*)tinfo);
913 (*type_info) [i] = tinfo;
914 (*ex_info)[i].try_start = code + block_start_offset;
915 (*ex_info)[i].try_end = code + block_start_offset + block_size;
916 (*ex_info)[i].handler_start = code + landing_pad;
922 * mono_unwind_decode_fde:
924 * Decode a DWARF FDE entry, returning the unwind opcodes.
925 * If not NULL, EX_INFO is set to a malloc-ed array of MonoJitExceptionInfo structures,
926 * only try_start, try_end and handler_start is set.
927 * If not NULL, TYPE_INFO is set to a malloc-ed array containing the ttype table from the
931 mono_unwind_decode_fde (guint8 *fde, guint32 *out_len, guint32 *code_len, MonoJitExceptionInfo **ex_info, guint32 *ex_info_len, gpointer **type_info, int *this_reg, int *this_offset)
933 guint8 *p, *cie, *fde_current, *fde_aug = NULL, *code, *fde_cfi, *cie_cfi;
934 gint32 fde_len, cie_offset, pc_begin, pc_range, aug_len;
935 gint32 cie_len, cie_id, cie_version, code_align, data_align, return_reg;
936 gint32 i, cie_aug_len, buf_len;
939 gboolean has_fde_augmentation = FALSE;
942 * http://refspecs.freestandards.org/LSB_3.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html
945 /* This is generated by JITDwarfEmitter::EmitEHFrame () */
954 // FIXME: Endianess ?
955 fde_len = *(guint32*)p;
956 g_assert (fde_len != 0xffffffff && fde_len != 0);
958 cie_offset = *(guint32*)p;
959 cie = p - cie_offset;
965 cie_len = *(guint32*)p;
967 cie_id = *(guint32*)p;
968 g_assert (cie_id == 0);
971 g_assert (cie_version == 1);
973 cie_aug_str = (char*)p;
974 p += strlen (cie_aug_str) + 1;
975 code_align = decode_uleb128 (p, &p);
976 data_align = decode_sleb128 (p, &p);
977 return_reg = decode_uleb128 (p, &p);
978 if (strstr (cie_aug_str, "z")) {
982 cie_aug_len = decode_uleb128 (p, &p);
984 has_fde_augmentation = TRUE;
987 for (i = 0; cie_aug_str [i] != '\0'; ++i) {
988 switch (cie_aug_str [i]) {
994 read_encoded_val (p_encoding, p, &p);
997 g_assert ((*p == (DW_EH_PE_sdata4|DW_EH_PE_pcrel)) || (*p == (DW_EH_PE_sdata8|DW_EH_PE_pcrel)));
1001 g_assert (*p == (DW_EH_PE_sdata4|DW_EH_PE_pcrel));
1005 g_assert_not_reached ();
1015 /* Continue decoding FDE */
1017 /* DW_EH_PE_sdata4|DW_EH_PE_pcrel encoding */
1018 pc_begin = *(gint32*)p;
1019 code = p + pc_begin;
1021 pc_range = *(guint32*)p;
1023 if (has_fde_augmentation) {
1024 aug_len = decode_uleb128 (p, &p);
1033 *code_len = pc_range;
1040 /* Decode FDE augmention */
1045 /* sdata|pcrel encoding */
1047 lsda_offset = read32 (fde_aug);
1048 else if (aug_len == 8)
1049 lsda_offset = *(gint64*)fde_aug;
1051 g_assert_not_reached ();
1052 if (lsda_offset != 0) {
1053 lsda = fde_aug + lsda_offset;
1055 decode_lsda (lsda, code, ex_info, ex_info_len, type_info, this_reg, this_offset);
1059 /* Make sure the FDE uses the same constants as we do */
1060 g_assert (code_align == 1);
1061 g_assert (data_align == DWARF_DATA_ALIGN);
1062 g_assert (return_reg == DWARF_PC_REG);
1064 buf_len = (cie + cie_len + 4 - cie_cfi) + (fde + fde_len + 4 - fde_cfi);
1065 buf = (guint8 *)g_malloc0 (buf_len);
1069 while (p < cie + cie_len + 4) {
1070 if (*p == DW_CFA_nop)
1073 decode_cie_op (p, &p);
1075 memcpy (buf + i, cie_cfi, p - cie_cfi);
1079 while (p < fde + fde_len + 4) {
1080 if (*p == DW_CFA_nop)
1083 decode_cie_op (p, &p);
1085 memcpy (buf + i, fde_cfi, p - fde_cfi);
1087 g_assert (i <= buf_len);
1091 return (guint8 *)g_realloc (buf, i);
1095 * mono_unwind_decode_mono_fde:
1097 * Decode an FDE entry in the LLVM emitted mono EH frame.
1098 * info->ex_info is set to a malloc-ed array of MonoJitExceptionInfo structures,
1099 * only try_start, try_end and handler_start is set.
1100 * info->type_info is set to a malloc-ed array containing the ttype table from the
1104 mono_unwind_decode_llvm_mono_fde (guint8 *fde, int fde_len, guint8 *cie, guint8 *code, MonoLLVMFDEInfo *res)
1106 guint8 *p, *fde_aug, *cie_cfi, *fde_cfi, *buf;
1107 int has_aug, aug_len, cie_cfi_len, fde_cfi_len;
1108 gint32 code_align, data_align, return_reg, pers_encoding;
1110 memset (res, 0, sizeof (*res));
1112 res->this_offset = -1;
1114 /* fde points to data emitted by LLVM in DwarfMonoException::EmitMonoEHFrame () */
1119 aug_len = read32 (p);
1131 /* The LSDA is embedded directly into the FDE */
1134 decode_lsda (lsda, code, &res->ex_info, &res->ex_info_len, &res->type_info, &res->this_reg, &res->this_offset);
1139 code_align = decode_uleb128 (p, &p);
1140 data_align = decode_sleb128 (p, &p);
1141 return_reg = decode_uleb128 (p, &p);
1144 if (pers_encoding != DW_EH_PE_omit)
1145 read_encoded_val (pers_encoding, p, &p);
1149 /* Make sure the FDE uses the same constants as we do */
1150 g_assert (code_align == 1);
1151 g_assert (data_align == DWARF_DATA_ALIGN);
1152 g_assert (return_reg == DWARF_PC_REG);
1154 /* Compute size of CIE unwind info it is DW_CFA_nop terminated */
1157 if (*p == DW_CFA_nop)
1160 decode_cie_op (p, &p);
1162 cie_cfi_len = p - cie_cfi;
1163 fde_cfi_len = (fde + fde_len - fde_cfi);
1165 buf = (guint8 *)g_malloc0 (cie_cfi_len + fde_cfi_len);
1166 memcpy (buf, cie_cfi, cie_cfi_len);
1167 memcpy (buf + cie_cfi_len, fde_cfi, fde_cfi_len);
1169 res->unw_info_len = cie_cfi_len + fde_cfi_len;
1170 res->unw_info = buf;
1174 * mono_unwind_get_cie_program:
1176 * Get the unwind bytecode for the DWARF CIE.
1179 mono_unwind_get_cie_program (void)
1181 #if defined(TARGET_AMD64) || defined(TARGET_X86) || defined(TARGET_POWERPC) || defined(TARGET_ARM)
1182 return mono_arch_get_cie_program ();