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