mono/mini/exceptions-ia64.c

   1 /*
   2  * exceptions-ia64.c: exception support for IA64
   3  *
   4  * Authors:
   5  *   Zoltan Varga (vargaz@gmail.com)
   6  *
   7  * (C) 2001 Ximian, Inc.
   8  */
   9
  10 /*
  11  * We implement exception handling with the help of the libuwind library:
  12  *
  13  * http://www.hpl.hp.com/research/linux/libunwind/
  14  *
  15  *  Under IA64 all functions are assumed to have unwind info, we do not need to save
  16  * the machine state in the LMF. But we have to generate unwind info for all
  17  * dynamically generated code.
  18  */
  19
  20 #include <config.h>
  21 #include <glib.h>
  22 #include <signal.h>
  23 #include <string.h>
  24 #include <sys/ucontext.h>
  25
  26 #include <mono/arch/ia64/ia64-codegen.h>
  27 #include <mono/metadata/appdomain.h>
  28 #include <mono/metadata/tabledefs.h>
  29 #include <mono/metadata/threads.h>
  30 #include <mono/metadata/debug-helpers.h>
  31 #include <mono/metadata/exception.h>
  32 #include <mono/metadata/gc-internal.h>
  33 #include <mono/metadata/mono-debug.h>
  34
  35 #include "mini.h"
  36 #include "mini-ia64.h"
  37
  38 #define ALIGN_TO(val,align) (((val) + ((align) - 1)) & ~((align) - 1))
  39
  40 #define NOT_IMPLEMENTED g_assert_not_reached ()
  41
  42 #define GP_SCRATCH_REG 31
  43 #define GP_SCRATCH_REG2 30
  44
  45 G_GNUC_UNUSED static void
  46 print_ctx (MonoContext *ctx)
  47 {
  48         char name[256];
  49         unw_word_t off, ip, sp;
  50         unw_proc_info_t pi;
  51         int res;
  52
  53         unw_get_proc_name (&ctx->cursor, name, 256, &off);
  54         unw_get_proc_info(&ctx->cursor, &pi);
  55         res = unw_get_reg (&ctx->cursor, UNW_IA64_IP, &ip);
  56         g_assert (res == 0);
  57         res = unw_get_reg (&ctx->cursor, UNW_IA64_SP, &sp);
  58         g_assert (res == 0);
  59
  60         printf ("%s:%lx [%lx-%lx] SP: %lx\n", name, ip - pi.start_ip, pi.start_ip, pi.end_ip, sp);
  61 }
  62
  63 static gpointer
  64 ia64_create_ftnptr (gpointer ptr)
  65 {
  66         gpointer *desc = mono_global_codeman_reserve (2 * sizeof (gpointer));
  67         desc [0] = ptr;
  68         desc [1] = NULL;
  69
  70         return desc;
  71 }
  72
  73 static void
  74 restore_context (MonoContext *ctx)
  75 {
  76         int res;
  77         unw_word_t ip;
  78
  79         res = unw_get_reg (&ctx->cursor, UNW_IA64_IP, &ip);
  80         g_assert (res == 0);
  81
  82         /* Set this to 0 to tell OP_START_HANDLER that it doesn't have to set the frame pointer */
  83         res = unw_set_reg (&ctx->cursor, UNW_IA64_GR + 15, 0);
  84         g_assert (res == 0);
  85
  86         unw_resume (&ctx->cursor);
  87 }
  88
  89 /*
  90  * mono_arch_get_restore_context:
  91  *
  92  * Returns a pointer to a method which restores a previously saved sigcontext.
  93  */
  94 gpointer
  95 mono_arch_get_restore_context (void)
  96 {
  97         return restore_context;
  98 }
  99
 100 static gpointer
 101 get_real_call_filter (void)
 102 {
 103         static gpointer filter;
 104         static gboolean inited = FALSE;
 105         guint8 *start;
 106         Ia64CodegenState code;
 107         int in0, local0, out0, nout;
 108         unw_dyn_info_t *di;
 109         unw_dyn_region_info_t *r_pro, *r_body, *r_epilog;
 110
 111         if (inited)
 112                 return filter;
 113
 114         start = mono_global_codeman_reserve (1024);
 115
 116         /* int call_filter (guint64 fp, guint64 ip) */
 117
 118         /*
 119          * We have to create a register+stack frame similar to the frame which
 120          * contains the filter.
 121          * - setting fp
 122          * - setting up a register stack frame
 123          * These cannot be set up in this function, because the fp register is a
 124          * stacked register which is different in each method. Also, the register
 125          * stack frame is different in each method. So we pass the FP value in a a
 126          * non-stacked register and the code generated by the OP_START_HANDLER
 127          * opcode will copy it to the appropriate register after setting up the
 128          * register stack frame.
 129          * The stacked registers are not need to be set since variables used in
 130          * handler regions are never allocated to registers.
 131          */
 132
 133         in0 = 32;
 134         local0 = in0 + 2;
 135         out0 = local0 + 4;
 136         nout = 0;
 137
 138         ia64_codegen_init (code, start);
 139
 140         ia64_codegen_set_one_ins_per_bundle (code, TRUE);
 141
 142         ia64_unw_save_reg (code, UNW_IA64_AR_PFS, UNW_IA64_GR + local0 + 0);
 143         ia64_alloc (code, local0 + 0, local0 - in0, out0 - local0, nout, 0);
 144         ia64_unw_save_reg (code, UNW_IA64_RP, UNW_IA64_GR + local0 + 1);
 145         ia64_mov_from_br (code, local0 + 1, IA64_B0);
 146
 147         ia64_begin_bundle (code);
 148
 149         r_pro = mono_ia64_create_unwind_region (&code);
 150
 151         /* Frame pointer */
 152         ia64_mov (code, IA64_R15, in0 + 0);
 153         /* Target ip */
 154         ia64_mov_to_br (code, IA64_B6, in0 + 1);
 155
 156         /* Call the filter */
 157         ia64_br_call_reg (code, IA64_B0, IA64_B6);
 158
 159         /* R8 contains the result of the filter */
 160
 161         /* FIXME: Add unwind info for this */
 162
 163         ia64_begin_bundle (code);
 164
 165         r_body = mono_ia64_create_unwind_region (&code);
 166         r_pro->next = r_body;
 167
 168         ia64_mov_to_ar_i (code, IA64_PFS, local0 + 0);
 169         ia64_mov_ret_to_br (code, IA64_B0, local0 + 1);
 170         ia64_br_ret_reg (code, IA64_B0);
 171
 172         ia64_begin_bundle (code);
 173
 174         r_epilog = mono_ia64_create_unwind_region (&code);
 175         r_body->next = r_epilog;
 176
 177         ia64_codegen_set_one_ins_per_bundle (code, FALSE);
 178
 179         ia64_codegen_close (code);
 180
 181         g_assert ((code.buf - start) <= 256);
 182
 183         mono_arch_flush_icache (start, code.buf - start);
 184
 185         di = g_malloc0 (sizeof (unw_dyn_info_t));
 186         di->start_ip = (unw_word_t) start;
 187         di->end_ip = (unw_word_t) code.buf;
 188         di->gp = 0;
 189         di->format = UNW_INFO_FORMAT_DYNAMIC;
 190         di->u.pi.name_ptr = (unw_word_t)"throw_trampoline";
 191         di->u.pi.regions = r_body;
 192
 193         _U_dyn_register (di);
 194
 195     filter = ia64_create_ftnptr (start);
 196
 197         inited = TRUE;
 198
 199         return filter;
 200 }
 201
 202 static int
 203 call_filter (MonoContext *ctx, gpointer ip)
 204 {
 205         int (*filter) (MonoContext *, gpointer);
 206         gpointer fp = MONO_CONTEXT_GET_BP (ctx);
 207
 208         filter = get_real_call_filter ();
 209
 210         return filter (fp, ip);
 211 }
 212
 213 /*
 214  * mono_arch_get_call_filter:
 215  *
 216  * Returns a pointer to a method which calls an exception filter. We
 217  * also use this function to call finally handlers (we pass NULL as
 218  * @exc object in this case).
 219  */
 220 gpointer
 221 mono_arch_get_call_filter (void)
 222 {
 223         /* Initialize the real filter non-lazily */
 224         get_real_call_filter ();
 225
 226         return call_filter;
 227 }
 228
 229 static void
 230 throw_exception (MonoObject *exc, guint64 rethrow)
 231 {
 232         unw_context_t unw_ctx;
 233         MonoContext ctx;
 234         MonoJitInfo *ji;
 235         unw_word_t ip, sp;
 236         int res;
 237
 238         if (mono_object_isinst (exc, mono_defaults.exception_class)) {
 239                 MonoException *mono_ex = (MonoException*)exc;
 240                 if (!rethrow)
 241                         mono_ex->stack_trace = NULL;
 242         }
 243
 244         res = unw_getcontext (&unw_ctx);
 245         g_assert (res == 0);
 246         res = unw_init_local (&ctx.cursor, &unw_ctx);
 247         g_assert (res == 0);
 248
 249         /*
 250          * Unwind until the first managed frame. This is needed since
 251          * mono_handle_exception expects the variables in the original context to
 252          * correspond to the method returned by mono_find_jit_info.
 253          */
 254         while (TRUE) {
 255                 res = unw_get_reg (&ctx.cursor, UNW_IA64_IP, &ip);
 256                 g_assert (res == 0);
 257
 258                 res = unw_get_reg (&ctx.cursor, UNW_IA64_SP, &sp);
 259                 g_assert (res == 0);
 260
 261                 ji = mono_jit_info_table_find (mono_domain_get (), (gpointer)ip);
 262
 263                 //printf ("UN: %s %lx %lx\n", ji ? ji->method->name : "", ip, sp);
 264
 265                 if (ji)
 266                         break;
 267
 268                 res = unw_step (&ctx.cursor);
 269
 270                 if (res == 0) {
 271                         /*
 272                          * This means an unhandled exception during the compilation of a
 273                          * topmost method like Main
 274                          */
 275                         break;
 276                 }
 277                 g_assert (res >= 0);
 278         }
 279
 280         mono_handle_exception (&ctx, exc, (gpointer)(ip), FALSE);
 281         restore_context (&ctx);
 282
 283         g_assert_not_reached ();
 284 }
 285
 286 static gpointer
 287 get_throw_trampoline (gboolean rethrow)
 288 {
 289         guint8* start;
 290         Ia64CodegenState code;
 291         gpointer ptr = throw_exception;
 292         int i, in0, local0, out0;
 293         unw_dyn_info_t *di;
 294         unw_dyn_region_info_t *r_pro;
 295
 296         start = mono_global_codeman_reserve (256);
 297
 298         in0 = 32;
 299         local0 = in0 + 1;
 300         out0 = local0 + 2;
 301
 302         ia64_codegen_init (code, start);
 303         ia64_alloc (code, local0 + 0, local0 - in0, out0 - local0, 3, 0);
 304         ia64_mov_from_br (code, local0 + 1, IA64_B0);
 305
 306         /* FIXME: This depends on the current instruction emitter */
 307
 308         r_pro = g_malloc0 (_U_dyn_region_info_size (2));
 309         r_pro->op_count = 2;
 310         r_pro->insn_count = 6;
 311         i = 0;
 312         _U_dyn_op_save_reg (&r_pro->op[i++], _U_QP_TRUE, /* when=*/ 2,
 313                                                 /* reg=*/ UNW_IA64_AR_PFS, /* dst=*/ UNW_IA64_GR + local0 + 0);
 314         _U_dyn_op_save_reg (&r_pro->op[i++], _U_QP_TRUE, /* when=*/ 5,
 315                                                 /* reg=*/ UNW_IA64_RP, /* dst=*/ UNW_IA64_GR + local0 + 1);
 316         g_assert ((unsigned) i <= r_pro->op_count);
 317
 318         /* Set args */
 319         ia64_mov (code, out0 + 0, in0 + 0);
 320         ia64_adds_imm (code, out0 + 1, rethrow, IA64_R0);
 321
 322         /* Call throw_exception */
 323         ia64_movl (code, GP_SCRATCH_REG, ptr);
 324         ia64_ld8_inc_imm (code, GP_SCRATCH_REG2, GP_SCRATCH_REG, 8);
 325         ia64_mov_to_br (code, IA64_B6, GP_SCRATCH_REG2);
 326         ia64_ld8 (code, IA64_GP, GP_SCRATCH_REG);
 327         ia64_br_call_reg (code, IA64_B0, IA64_B6);
 328
 329         /* Not reached */
 330         ia64_break_i (code, 1000);
 331         ia64_codegen_close (code);
 332
 333         g_assert ((code.buf - start) <= 256);
 334
 335         mono_arch_flush_icache (start, code.buf - start);
 336
 337         di = g_malloc0 (sizeof (unw_dyn_info_t));
 338         di->start_ip = (unw_word_t) start;
 339         di->end_ip = (unw_word_t) code.buf;
 340         di->gp = 0;
 341         di->format = UNW_INFO_FORMAT_DYNAMIC;
 342         di->u.pi.name_ptr = (unw_word_t)"throw_trampoline";
 343         di->u.pi.regions = r_pro;
 344
 345         _U_dyn_register (di);
 346
 347         return ia64_create_ftnptr (start);
 348 }
 349
 350 /**
 351  * mono_arch_get_throw_exception:
 352  *
 353  * Returns a function pointer which can be used to raise
 354  * exceptions. The returned function has the following
 355  * signature: void (*func) (MonoException *exc);
 356  *
 357  */
 358 gpointer
 359 mono_arch_get_throw_exception (void)
 360 {
 361         static guint8* start;
 362         static gboolean inited = FALSE;
 363
 364         if (inited)
 365                 return start;
 366
 367         start = get_throw_trampoline (FALSE);
 368
 369         inited = TRUE;
 370
 371         return start;
 372 }
 373
 374 gpointer
 375 mono_arch_get_rethrow_exception (void)
 376 {
 377         static guint8* start;
 378         static gboolean inited = FALSE;
 379
 380         if (inited)
 381                 return start;
 382
 383         start = get_throw_trampoline (TRUE);
 384
 385         inited = TRUE;
 386
 387         return start;
 388 }
 389
 390 gpointer
 391 mono_arch_get_throw_exception_by_name (void)
 392 {
 393         guint8* start;
 394         Ia64CodegenState code;
 395
 396         start = mono_global_codeman_reserve (64);
 397
 398         /* Not used on ia64 */
 399         ia64_codegen_init (code, start);
 400         ia64_break_i (code, 1001);
 401         ia64_codegen_close (code);
 402
 403         g_assert ((code.buf - start) <= 256);
 404
 405         mono_arch_flush_icache (start, code.buf - start);
 406
 407         return start;
 408 }
 409
 410 /**
 411  * mono_arch_get_throw_corlib_exception:
 412  *
 413  * Returns a function pointer which can be used to raise
 414  * corlib exceptions. The returned function has the following
 415  * signature: void (*func) (guint32 ex_token_index, guint32 offset);
 416  * Here, offset is the offset which needs to be substracted from the caller IP
 417  * to get the IP of the throw. Passing the offset has the advantage that it
 418  * needs no relocations in the caller.
 419  */
 420 gpointer
 421 mono_arch_get_throw_corlib_exception (void)
 422 {
 423         static guint8* res;
 424         static gboolean inited = FALSE;
 425         guint8 *start;
 426         gpointer ptr;
 427         int i, in0, local0, out0, nout;
 428         Ia64CodegenState code;
 429         unw_dyn_info_t *di;
 430         unw_dyn_region_info_t *r_pro;
 431
 432         if (inited)
 433                 return res;
 434
 435         start = mono_global_codeman_reserve (1024);
 436
 437         in0 = 32;
 438         local0 = in0 + 2;
 439         out0 = local0 + 4;
 440         nout = 3;
 441
 442         ia64_codegen_init (code, start);
 443         ia64_alloc (code, local0 + 0, local0 - in0, out0 - local0, nout, 0);
 444         ia64_mov_from_br (code, local0 + 1, IA64_RP);
 445
 446         r_pro = g_malloc0 (_U_dyn_region_info_size (2));
 447         r_pro->op_count = 2;
 448         r_pro->insn_count = 6;
 449         i = 0;
 450         _U_dyn_op_save_reg (&r_pro->op[i++], _U_QP_TRUE, /* when=*/ 2,
 451                                                 /* reg=*/ UNW_IA64_AR_PFS, /* dst=*/ UNW_IA64_GR + local0 + 0);
 452         _U_dyn_op_save_reg (&r_pro->op[i++], _U_QP_TRUE, /* when=*/ 5,
 453                                                 /* reg=*/ UNW_IA64_RP, /* dst=*/ UNW_IA64_GR + local0 + 1);
 454         g_assert ((unsigned) i <= r_pro->op_count);
 455
 456         /* Call exception_from_token */
 457         ia64_movl (code, out0 + 0, mono_defaults.exception_class->image);
 458         ia64_mov (code, out0 + 1, in0 + 0);
 459         ia64_movl (code, GP_SCRATCH_REG, MONO_TOKEN_TYPE_DEF);
 460         ia64_add (code, out0 + 1, in0 + 0, GP_SCRATCH_REG);
 461         ptr = mono_exception_from_token;
 462         ia64_movl (code, GP_SCRATCH_REG, ptr);
 463         ia64_ld8_inc_imm (code, GP_SCRATCH_REG2, GP_SCRATCH_REG, 8);
 464         ia64_mov_to_br (code, IA64_B6, GP_SCRATCH_REG2);
 465         ia64_ld8 (code, IA64_GP, GP_SCRATCH_REG);
 466         ia64_br_call_reg (code, IA64_B0, IA64_B6);
 467         ia64_mov (code, local0 + 3, IA64_R8);
 468
 469         /* Compute throw ip */
 470         ia64_mov (code, local0 + 2, local0 + 1);
 471         ia64_sub (code, local0 + 2, local0 + 2, in0 + 1);
 472
 473         /* Trick the unwind library into using throw_ip as the IP in the caller frame */
 474         ia64_mov (code, local0 + 1, local0 + 2);
 475
 476         /* Set args */
 477         ia64_mov (code, out0 + 0, local0 + 3);
 478         ia64_mov (code, out0 + 1, IA64_R0);
 479
 480         /* Call throw_exception */
 481         ptr = throw_exception;
 482         ia64_movl (code, GP_SCRATCH_REG, ptr);
 483         ia64_ld8_inc_imm (code, GP_SCRATCH_REG2, GP_SCRATCH_REG, 8);
 484         ia64_mov_to_br (code, IA64_B6, GP_SCRATCH_REG2);
 485         ia64_ld8 (code, IA64_GP, GP_SCRATCH_REG);
 486         ia64_br_call_reg (code, IA64_B0, IA64_B6);
 487
 488         ia64_break_i (code, 1002);
 489         ia64_codegen_close (code);
 490
 491         g_assert ((code.buf - start) <= 1024);
 492
 493         di = g_malloc0 (sizeof (unw_dyn_info_t));
 494         di->start_ip = (unw_word_t) start;
 495         di->end_ip = (unw_word_t) code.buf;
 496         di->gp = 0;
 497         di->format = UNW_INFO_FORMAT_DYNAMIC;
 498         di->u.pi.name_ptr = (unw_word_t)"throw_corlib_exception_trampoline";
 499         di->u.pi.regions = r_pro;
 500
 501         _U_dyn_register (di);
 502
 503         mono_arch_flush_icache (start, code.buf - start);
 504
 505         res = ia64_create_ftnptr (start);
 506         inited = TRUE;
 507
 508         return res;
 509 }
 510
 511 /* mono_arch_find_jit_info:
 512  *
 513  * This function is used to gather information from @ctx. It return the
 514  * MonoJitInfo of the corresponding function, unwinds one stack frame and
 515  * stores the resulting context into @new_ctx. It also stores a string
 516  * describing the stack location into @trace (if not NULL), and modifies
 517  * the @lmf if necessary. @native_offset return the IP offset from the
 518  * start of the function or -1 if that info is not available.
 519  */
 520 MonoJitInfo *
 521 mono_arch_find_jit_info (MonoDomain *domain, MonoJitTlsData *jit_tls, MonoJitInfo *res, MonoJitInfo *prev_ji, MonoContext *ctx,
 522                          MonoContext *new_ctx, char **trace, MonoLMF **lmf, int *native_offset,
 523                          gboolean *managed)
 524 {
 525         MonoJitInfo *ji;
 526         int err;
 527         unw_word_t ip;
 528
 529         *new_ctx = *ctx;
 530
 531         while (TRUE) {
 532                 err = unw_get_reg (&new_ctx->cursor, UNW_IA64_IP, &ip);
 533                 g_assert (err == 0);
 534
 535                 /* Avoid costly table lookup during stack overflow */
 536                 if (prev_ji && ((guint8*)ip > (guint8*)prev_ji->code_start && ((guint8*)ip < ((guint8*)prev_ji->code_start) + prev_ji->code_size)))
 537                         ji = prev_ji;
 538                 else
 539                         ji = mono_jit_info_table_find (domain, (gpointer)ip);
 540
 541                 if (managed)
 542                         *managed = FALSE;
 543
 544                 /*
 545                 {
 546                         char name[256];
 547                         unw_word_t off;
 548
 549                         unw_get_proc_name (&new_ctx->cursor, name, 256, &off);
 550                         printf ("F: %s\n", name);
 551                 }
 552                 */
 553
 554                 if (ji != NULL) {
 555                         if (managed)
 556                                 if (!ji->method->wrapper_type)
 557                                         *managed = TRUE;
 558
 559                         break;
 560                 }
 561
 562                 /* This is an unmanaged frame, so just unwind through it */
 563                 /* FIXME: This returns -3 for the __clone2 frame in libc */
 564                 err = unw_step (&new_ctx->cursor);
 565                 if (err < 0)
 566                         break;
 567
 568                 if (err == 0)
 569                         break;
 570         }
 571
 572         if (ji) {
 573                 //print_ctx (new_ctx);
 574
 575                 err = unw_step (&new_ctx->cursor);
 576                 g_assert (err >= 0);
 577
 578                 //print_ctx (new_ctx);
 579
 580                 return ji;
 581         }
 582         else
 583                 return (gpointer)(gssize)-1;
 584 }
 585
 586 /**
 587  * mono_arch_handle_exception:
 588  *
 589  * @ctx: saved processor state
 590  * @obj: the exception object
 591  */
 592 gboolean
 593 mono_arch_handle_exception (void *sigctx, gpointer obj, gboolean test_only)
 594 {
 595         /* libunwind takes care of this */
 596         unw_context_t unw_ctx;
 597         MonoContext ctx;
 598         MonoJitInfo *ji;
 599         unw_word_t ip;
 600         int res;
 601
 602         res = unw_getcontext (&unw_ctx);
 603         g_assert (res == 0);
 604         res = unw_init_local (&ctx.cursor, &unw_ctx);
 605         g_assert (res == 0);
 606
 607         /*
 608          * Unwind until the first managed frame. This skips the signal handler frames
 609          * too.
 610          */
 611         while (TRUE) {
 612                 res = unw_get_reg (&ctx.cursor, UNW_IA64_IP, &ip);
 613                 g_assert (res == 0);
 614
 615                 ji = mono_jit_info_table_find (mono_domain_get (), (gpointer)ip);
 616
 617                 if (ji)
 618                         break;
 619
 620                 res = unw_step (&ctx.cursor);
 621                 g_assert (res >= 0);
 622         }
 623
 624         mono_handle_exception (&ctx, obj, (gpointer)ip, test_only);
 625
 626         restore_context (&ctx);
 627
 628         g_assert_not_reached ();
 629 }
 630
 631 gpointer
 632 mono_arch_ip_from_context (void *sigctx)
 633 {
 634         ucontext_t *ctx = (ucontext_t*)sigctx;
 635
 636         return (gpointer)ctx->uc_mcontext.sc_ip;
 637 }