mono/mini/exceptions-mips.c

   1 /*
   2  * exceptions-mips.c: exception support for MIPS
   3  *
   4  * Authors:
   5  *   Mark Mason (mason@broadcom.com)
   6  *
   7  * Based on exceptions-ppc.c by:
   8  *   Dietmar Maurer (dietmar@ximian.com)
   9  *   Paolo Molaro (lupus@ximian.com)
  10  *
  11  * (C) 2006 Broadcom
  12  * (C) 2001 Ximian, Inc.
  13  */
  14
  15 #include <config.h>
  16 #include <glib.h>
  17 #include <signal.h>
  18 #include <string.h>
  19 #include <ucontext.h>
  20
  21 #include <mono/arch/mips/mips-codegen.h>
  22 #include <mono/metadata/appdomain.h>
  23 #include <mono/metadata/tabledefs.h>
  24 #include <mono/metadata/threads.h>
  25 #include <mono/metadata/debug-helpers.h>
  26 #include <mono/metadata/exception.h>
  27 #include <mono/metadata/mono-debug.h>
  28
  29 #include "mini.h"
  30 #include "mini-mips.h"
  31
  32 #define GENERIC_EXCEPTION_SIZE 256
  33
  34 /* XXX */
  35 #if 1
  36 #define restore_regs_from_context(ctx_reg,ip_reg,tmp_reg) do {  \
  37         } while (0)
  38 #else
  39 #define restore_regs_from_context(ctx_reg,pc,tmp_reg) do {      \
  40                 int reg;        \
  41                 ppc_lwz (code, pc, G_STRUCT_OFFSET (MonoContext, sc_pc), ctx_reg);      \
  42                 ppc_lmw (code, ppc_r13, ctx_reg, G_STRUCT_OFFSET (MonoContext, sc_regs));       \
  43                 for (reg = 0; reg < MONO_SAVED_FREGS; ++reg) {  \
  44                         ppc_lfd (code, (14 + reg), G_STRUCT_OFFSET(MonoLMF, sc_fpregs) + reg * sizeof (gdouble), ctx_reg);      \
  45                 }       \
  46         } while (0)
  47 #endif
  48
  49 /* nothing to do */
  50 #define setup_context(ctx) do { \
  51                 memset ((ctx), 0, sizeof(*(ctx)));      \
  52         } while (0);
  53
  54 /*
  55  * mono_arch_get_restore_context:
  56  *
  57  * Returns a pointer to a method which restores a previously saved MonoContext.
  58  * The first argument in a0 is the pointer to the MonoContext.
  59  */
  60 gpointer
  61 mono_arch_get_restore_context (MonoTrampInfo **info, gboolean aot)
  62 {
  63         int i;
  64         guint8 *code;
  65         static guint8 start [128];
  66         static int inited = 0;
  67         guint32 iregs_to_restore;
  68
  69         g_assert (!aot);
  70         if (info)
  71                 *info = NULL;
  72
  73         if (inited)
  74                 return start;
  75         inited = 1;
  76         code = start;
  77
  78         iregs_to_restore = (MONO_ARCH_CALLEE_SAVED_REGS \
  79                             | (1 << mips_sp) | (1 << mips_ra));
  80         for (i = 0; i < MONO_SAVED_GREGS; ++i) {
  81                 if (iregs_to_restore & (1 << i)) {
  82                         MIPS_LW (code, i, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[i]));
  83                 }
  84         }
  85
  86         /* Get the address to return to */
  87         mips_lw (code, mips_t9, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_pc));
  88
  89         /* jump to the saved IP */
  90         mips_jr (code, mips_t9);
  91         mips_nop (code);
  92
  93         /* never reached */
  94         mips_break (code, 0xff);
  95
  96         g_assert ((code - start) < sizeof(start));
  97         mono_arch_flush_icache (start, code - start);
  98         return start;
  99 }
 100
 101 /*
 102  * mono_arch_get_call_filter:
 103  *
 104  * Returns a pointer to a method which calls an exception filter. We
 105  * also use this function to call finally handlers (we pass NULL as
 106  * @exc object in this case).
 107  *
 108  * This function is invoked as
 109  *      call_handler (MonoContext *ctx, handler)
 110  *
 111  * Where 'handler' is a function to be invoked as:
 112  *      handler (void)
 113  */
 114 gpointer
 115 mono_arch_get_call_filter (MonoTrampInfo **info, gboolean aot)
 116 {
 117         static guint8 start [320];
 118         static int inited = 0;
 119         guint8 *code;
 120         int alloc_size;
 121         int offset;
 122
 123         g_assert (!aot);
 124         if (info)
 125                 *info = NULL;
 126
 127         if (inited)
 128                 return start;
 129
 130         inited = 1;
 131         code = start;
 132
 133         alloc_size = 64;
 134         g_assert ((alloc_size & (MIPS_STACK_ALIGNMENT-1)) == 0);
 135
 136         mips_addiu (code, mips_sp, mips_sp, -alloc_size);
 137         mips_sw (code, mips_ra, mips_sp, alloc_size + MIPS_RET_ADDR_OFFSET);
 138
 139         /* Save global registers on stack (s0 - s7) */
 140         offset = 16;
 141         MIPS_SW (code, mips_s0, mips_sp, offset); offset += IREG_SIZE;
 142         MIPS_SW (code, mips_s1, mips_sp, offset); offset += IREG_SIZE;
 143         MIPS_SW (code, mips_s2, mips_sp, offset); offset += IREG_SIZE;
 144         MIPS_SW (code, mips_s3, mips_sp, offset); offset += IREG_SIZE;
 145         MIPS_SW (code, mips_s4, mips_sp, offset); offset += IREG_SIZE;
 146         MIPS_SW (code, mips_s5, mips_sp, offset); offset += IREG_SIZE;
 147         MIPS_SW (code, mips_s6, mips_sp, offset); offset += IREG_SIZE;
 148         MIPS_SW (code, mips_s7, mips_sp, offset); offset += IREG_SIZE;
 149         MIPS_SW (code, mips_fp, mips_sp, offset); offset += IREG_SIZE;
 150
 151         /* Restore global registers from MonoContext, including the frame pointer */
 152         MIPS_LW (code, mips_s0, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s0]));
 153         MIPS_LW (code, mips_s1, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s1]));
 154         MIPS_LW (code, mips_s2, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s2]));
 155         MIPS_LW (code, mips_s3, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s3]));
 156         MIPS_LW (code, mips_s4, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s4]));
 157         MIPS_LW (code, mips_s5, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s5]));
 158         MIPS_LW (code, mips_s6, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s6]));
 159         MIPS_LW (code, mips_s7, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_s7]));
 160         MIPS_LW (code, mips_fp, mips_a0, G_STRUCT_OFFSET (MonoContext, sc_regs[mips_fp]));
 161
 162         /* a1 is the handler to call */
 163         mips_move (code, mips_t9, mips_a1);
 164
 165         /* jump to the saved IP */
 166         mips_jalr (code, mips_t9, mips_ra);
 167         mips_nop (code);
 168
 169         /* restore all regs from the stack */
 170         offset = 16;
 171         MIPS_LW (code, mips_s0, mips_sp, offset); offset += IREG_SIZE;
 172         MIPS_LW (code, mips_s1, mips_sp, offset); offset += IREG_SIZE;
 173         MIPS_LW (code, mips_s2, mips_sp, offset); offset += IREG_SIZE;
 174         MIPS_LW (code, mips_s3, mips_sp, offset); offset += IREG_SIZE;
 175         MIPS_LW (code, mips_s4, mips_sp, offset); offset += IREG_SIZE;
 176         MIPS_LW (code, mips_s5, mips_sp, offset); offset += IREG_SIZE;
 177         MIPS_LW (code, mips_s6, mips_sp, offset); offset += IREG_SIZE;
 178         MIPS_LW (code, mips_s7, mips_sp, offset); offset += IREG_SIZE;
 179         MIPS_LW (code, mips_fp, mips_sp, offset); offset += IREG_SIZE;
 180
 181         /* epilog */
 182         mips_lw (code, mips_ra, mips_sp, alloc_size + MIPS_RET_ADDR_OFFSET);
 183         mips_addiu (code, mips_sp, mips_sp, alloc_size);
 184         mips_jr (code, mips_ra);
 185         mips_nop (code);
 186
 187         g_assert ((code - start) < sizeof(start));
 188         mono_arch_flush_icache (start, code - start);
 189         return start;
 190 }
 191
 192 static void
 193 throw_exception (MonoObject *exc, unsigned long eip, unsigned long esp, gboolean rethrow)
 194 {
 195         static void (*restore_context) (MonoContext *);
 196         MonoContext ctx;
 197
 198 #ifdef DEBUG_EXCEPTIONS
 199         g_print ("throw_exception: exc=%p eip=%p esp=%p rethrow=%d\n",
 200                  exc, (void *)eip, (void *) esp, rethrow);
 201 #endif
 202
 203         if (!restore_context)
 204                 restore_context = mono_get_restore_context ();
 205
 206         /* adjust eip so that it point into the call instruction */
 207         eip -= 8;
 208
 209         setup_context (&ctx);
 210
 211         /*g_print  ("stack in throw: %p\n", esp);*/
 212         memcpy (&ctx.sc_regs, (void *)(esp + MIPS_STACK_PARAM_OFFSET),
 213                 sizeof (gulong) * MONO_SAVED_GREGS);
 214         memset (&ctx.sc_fpregs, 0, sizeof (mips_freg) * MONO_SAVED_FREGS);
 215         MONO_CONTEXT_SET_IP (&ctx, eip);
 216
 217         if (mono_object_isinst (exc, mono_defaults.exception_class)) {
 218                 MonoException *mono_ex = (MonoException*)exc;
 219                 if (!rethrow)
 220                         mono_ex->stack_trace = NULL;
 221         }
 222         mono_handle_exception (&ctx, exc, (void *)eip, FALSE);
 223 #ifdef DEBUG_EXCEPTIONS
 224         g_print ("throw_exception: restore to pc=%p sp=%p fp=%p ctx=%p\n",
 225                  (void *) ctx.sc_pc, (void *) ctx.sc_regs[mips_sp],
 226                  (void *) ctx.sc_regs[mips_fp], &ctx);
 227 #endif
 228         restore_context (&ctx);
 229
 230         g_assert_not_reached ();
 231 }
 232
 233 /**
 234  * arch_get_throw_exception_generic:
 235  *
 236  * Returns a function pointer which can be used to raise
 237  * exceptions. The returned function has the following
 238  * signature: void (*func) (MonoException *exc); or
 239  * void (*func) (char *exc_name);
 240  *
 241  */
 242 static gpointer
 243 mono_arch_get_throw_exception_generic (guint8 *start, int size, int corlib, gboolean rethrow)
 244 {
 245         guint8 *code;
 246         int alloc_size, pos, i;
 247
 248         code = start;
 249
 250         //g_print ("mono_arch_get_throw_exception_generic: code=%p\n", code);
 251
 252         pos = 0;
 253         /* XXX - save all the FP regs on the stack ? */
 254
 255         pos += MONO_MAX_IREGS * sizeof(guint32);
 256
 257         alloc_size = MIPS_MINIMAL_STACK_SIZE + pos + 64;
 258         // align to MIPS_STACK_ALIGNMENT bytes
 259         alloc_size += MIPS_STACK_ALIGNMENT - 1;
 260         alloc_size &= ~(MIPS_STACK_ALIGNMENT - 1);
 261
 262         g_assert ((alloc_size & (MIPS_STACK_ALIGNMENT-1)) == 0);
 263         mips_addiu (code, mips_sp, mips_sp, -alloc_size);
 264         mips_sw (code, mips_ra, mips_sp, alloc_size + MIPS_RET_ADDR_OFFSET);
 265
 266         /* Save all the regs on the stack */
 267         for (i = 0; i < MONO_MAX_IREGS; i++) {
 268                 if (i != mips_sp)
 269                         MIPS_SW (code, i, mips_sp, i*IREG_SIZE + MIPS_STACK_PARAM_OFFSET);
 270                 else {
 271                         mips_addiu (code, mips_at, mips_sp, alloc_size);
 272                         MIPS_SW (code, mips_at, mips_sp, i*IREG_SIZE + MIPS_STACK_PARAM_OFFSET);
 273                 }
 274         }
 275
 276         if (corlib) {
 277                 mips_move (code, mips_a1, mips_a0);
 278                 mips_load (code, mips_a0, mono_defaults.corlib);
 279                 mips_load (code, mips_t9, mono_exception_from_token);
 280                 mips_jalr (code, mips_t9, mips_ra);
 281                 mips_nop (code);
 282                 mips_move (code, mips_a0, mips_v0);
 283         }
 284         /* call throw_exception (exc, ip, sp, rethrow) */
 285
 286         /* exc is already in place in a0 */
 287
 288         /* pointer to ip */
 289         if (corlib)
 290                 mips_lw (code, mips_a1, mips_sp, alloc_size + MIPS_RET_ADDR_OFFSET);
 291         else
 292                 mips_move (code, mips_a1, mips_ra);
 293
 294         /* current sp & rethrow */
 295         mips_move (code, mips_a2, mips_sp);
 296         mips_addiu (code, mips_a3, mips_zero, rethrow);
 297
 298         mips_load (code, mips_t9, throw_exception);
 299         mips_jr (code, mips_t9);
 300         mips_nop (code);
 301         /* we should never reach this breakpoint */
 302         mips_break (code, 0xfe);
 303
 304         g_assert ((code - start) < size);
 305         mono_arch_flush_icache (start, code - start);
 306         return start;
 307 }
 308
 309 /**
 310  * mono_arch_get_rethrow_exception:
 311  *
 312  * Returns a function pointer which can be used to rethrow
 313  * exceptions. The returned function has the following
 314  * signature: void (*func) (MonoException *exc);
 315  *
 316  */
 317 gpointer
 318 mono_arch_get_rethrow_exception (MonoTrampInfo **info, gboolean aot)
 319 {
 320         static guint8 start [GENERIC_EXCEPTION_SIZE];
 321         static int inited = 0;
 322
 323         g_assert (!aot);
 324         if (info)
 325                 *info = NULL;
 326
 327         if (inited)
 328                 return start;
 329         mono_arch_get_throw_exception_generic (start, sizeof (start), FALSE, TRUE);
 330         inited = 1;
 331         return start;
 332 }
 333
 334 /**
 335  * arch_get_throw_exception:
 336  *
 337  * Returns a function pointer which can be used to raise
 338  * exceptions. The returned function has the following
 339  * signature: void (*func) (MonoException *exc);
 340  * For example to raise an arithmetic exception you can use:
 341  *
 342  * x86_push_imm (code, mono_get_exception_arithmetic ());
 343  * x86_call_code (code, arch_get_throw_exception ());
 344  *
 345  */
 346 gpointer
 347 mono_arch_get_throw_exception (MonoTrampInfo **info, gboolean aot)
 348 {
 349         static guint8 start [GENERIC_EXCEPTION_SIZE];
 350         static int inited = 0;
 351
 352         g_assert (!aot);
 353         if (info)
 354                 *info = NULL;
 355
 356         if (inited)
 357                 return start;
 358         mono_arch_get_throw_exception_generic (start, sizeof (start), FALSE, FALSE);
 359         inited = 1;
 360         return start;
 361 }
 362
 363 gpointer
 364 mono_arch_get_throw_exception_by_name (void)
 365 {
 366         guint8 *start, *code;
 367         int size = 64;
 368
 369         /* Not used on MIPS */
 370         start = code = mono_global_codeman_reserve (size);
 371         mips_break (code, 0xfd);
 372         mono_arch_flush_icache (start, code - start);
 373         return start;
 374 }
 375
 376 /**
 377  * mono_arch_get_throw_corlib_exception:
 378  *
 379  * Returns a function pointer which can be used to raise
 380  * corlib exceptions. The returned function has the following
 381  * signature: void (*func) (guint32 ex_token, guint32 offset);
 382  * On MIPS, the offset argument is missing.
 383  */
 384 gpointer
 385 mono_arch_get_throw_corlib_exception (MonoTrampInfo **info, gboolean aot)
 386 {
 387         static guint8 start [GENERIC_EXCEPTION_SIZE];
 388         static int inited = 0;
 389
 390         g_assert (!aot);
 391         if (info)
 392                 *info = NULL;
 393
 394         if (inited)
 395                 return start;
 396         mono_arch_get_throw_exception_generic (start, sizeof (start), TRUE, FALSE);
 397         inited = 1;
 398         return start;
 399 }
 400
 401 /*
 402  * mono_arch_find_jit_info:
 403  *
 404  * This function is used to gather information from @ctx, and store it in @frame_info.
 405  * It unwinds one stack frame, and stores the resulting context into @new_ctx. @lmf
 406  * is modified if needed.
 407  * Returns TRUE on success, FALSE otherwise.
 408  */
 409 gboolean
 410 mono_arch_find_jit_info (MonoDomain *domain, MonoJitTlsData *jit_tls,
 411                                                          MonoJitInfo *ji, MonoContext *ctx,
 412                                                          MonoContext *new_ctx, MonoLMF **lmf,
 413                                                          mgreg_t **save_locations,
 414                                                          StackFrameInfo *frame)
 415 {
 416         memset (frame, 0, sizeof (StackFrameInfo));
 417         frame->ji = ji;
 418
 419         *new_ctx = *ctx;
 420
 421         if (ji != NULL) {
 422                 gint32 address;
 423                 gpointer ip = MONO_CONTEXT_GET_IP (ctx);
 424                 gpointer fp = MONO_CONTEXT_GET_BP (ctx);
 425                 guint32 sp;
 426
 427                 frame->type = FRAME_TYPE_MANAGED;
 428
 429                 if (*lmf && (fp >= (gpointer)(*lmf)->ebp)) {
 430                         /* remove any unused lmf */
 431                         *lmf = (*lmf)->previous_lmf;
 432                 }
 433
 434                 address = (char *)ip - (char *)ji->code_start;
 435
 436                 /* Compute the previous stack frame, assuming method
 437                  * starts with addiu sp, sp, <offset>. */
 438                 sp = (guint32)(fp) - (short)(*(guint32 *)(ji->code_start));
 439
 440                 /* Sanity check the frame */
 441                 if (!sp || (sp == 0xffffffff)
 442                     || (sp & 0x07) || (sp < 64*1024)) {
 443 #ifdef DEBUG_EXCEPTIONS
 444                         g_print ("mono_arch_find_jit_info: bad stack sp=%p\n", (void *) sp);
 445 #endif
 446                         return FALSE;
 447                 }
 448
 449                 if (ji->method->save_lmf && 0) {
 450                         /* only enable this when prologue stops emitting
 451                          * normal save of s-regs when save_lmf is true.
 452                          * Will have to sync with prologue code at that point.
 453                          */
 454                         memcpy (&new_ctx->sc_fpregs,
 455                                 (char*)sp - sizeof (float) * MONO_SAVED_FREGS,
 456                                 sizeof (float) * MONO_SAVED_FREGS);
 457                         memcpy (&new_ctx->sc_regs,
 458                                 (char*)sp - sizeof (float) * MONO_SAVED_FREGS - sizeof (gulong) * MONO_SAVED_GREGS,
 459                                 sizeof (gulong) * MONO_SAVED_GREGS);
 460                 } else if (ji->used_regs) {
 461                         guint32 *insn;
 462                         guint32 mask = ji->used_regs;
 463
 464                         /* these all happen before adjustment of fp */
 465                         /* Look for sw ??, ????(sp) */
 466                         insn = ((guint32 *)ji->code_start) + 1;
 467                         while (!*insn || ((*insn & 0xffe00000) == 0xafa00000) || ((*insn & 0xffe00000) == 0xffa00000)) {
 468                                 int reg = (*insn >> 16) & 0x1f;
 469                                 guint32 addr = (((guint32)fp) + (short)(*insn & 0x0000ffff));
 470
 471                                 mask &= ~(1 << reg);
 472                                 if ((*insn & 0xffe00000) == 0xafa00000)
 473                                         new_ctx->sc_regs [reg] = *(guint32 *)addr;
 474                                 else
 475                                         new_ctx->sc_regs [reg] = *(guint64 *)addr;
 476                                 insn++;
 477                         }
 478                         MONO_CONTEXT_SET_SP (new_ctx, sp);
 479                         MONO_CONTEXT_SET_BP (new_ctx, sp);
 480                         /* assert that we found all registers we were supposed to */
 481                         g_assert (!mask);
 482                 }
 483                 /* we substract 8, so that the IP points into the call instruction */
 484                 MONO_CONTEXT_SET_IP (new_ctx, new_ctx->sc_regs[mips_ra] - 8);
 485
 486                 /* Sanity check -- we should have made progress here */
 487                 g_assert (MONO_CONTEXT_GET_BP (new_ctx) != MONO_CONTEXT_GET_BP (ctx));
 488                 return TRUE;
 489         } else if (*lmf) {
 490                 if (!(*lmf)->method) {
 491 #ifdef DEBUG_EXCEPTIONS
 492                         g_print ("mono_arch_find_jit_info: bad lmf @ %p\n", (void *) *lmf);
 493 #endif
 494                         return FALSE;
 495                 }
 496                 g_assert (((*lmf)->magic == MIPS_LMF_MAGIC1) || ((*lmf)->magic == MIPS_LMF_MAGIC2));
 497
 498                 ji = mini_jit_info_table_find (domain, (gpointer)(*lmf)->eip, NULL);
 499                 if (!ji) {
 500                         // FIXME: This can happen with multiple appdomains (bug #444383)
 501                         return FALSE;
 502                 }
 503
 504                 frame->ji = ji;
 505                 frame->type = FRAME_TYPE_MANAGED_TO_NATIVE;
 506
 507                 memcpy (&new_ctx->sc_regs, (*lmf)->iregs, sizeof (gulong) * MONO_SAVED_GREGS);
 508                 memcpy (&new_ctx->sc_fpregs, (*lmf)->fregs, sizeof (float) * MONO_SAVED_FREGS);
 509                 MONO_CONTEXT_SET_IP (new_ctx, (*lmf)->eip);
 510                 /* ensure that we've made progress */
 511                 g_assert (new_ctx->sc_pc != ctx->sc_pc);
 512                 *lmf = (*lmf)->previous_lmf;
 513
 514                 return TRUE;
 515         }
 516
 517         return FALSE;
 518 }
 519
 520 void
 521 mono_arch_sigctx_to_monoctx (void *sigctx, MonoContext *mctx)
 522 {
 523         int i;
 524         struct sigcontext *ctx = (struct sigcontext *)sigctx;
 525
 526         mctx->sc_pc = ctx->sc_pc;
 527         for (i = 0; i < 32; ++i) {
 528                 mctx->sc_regs[i] = ctx->sc_regs[i];
 529                 mctx->sc_fpregs[i] = ctx->sc_fpregs[i];
 530         }
 531 }
 532
 533 void
 534 mono_arch_monoctx_to_sigctx (MonoContext *mctx, void *sigctx)
 535 {
 536         int i;
 537         struct sigcontext *ctx = (struct sigcontext *)sigctx;
 538
 539         ctx->sc_pc = mctx->sc_pc;
 540         for (i = 0; i < 32; ++i) {
 541                 ctx->sc_regs[i] = mctx->sc_regs[i];
 542                 ctx->sc_fpregs[i] = mctx->sc_fpregs[i];
 543         }
 544 }
 545
 546 gpointer
 547 mono_arch_ip_from_context (void *sigctx)
 548 {
 549         struct sigcontext *ctx = (struct sigcontext *)sigctx;
 550         return (gpointer)(guint32)ctx->sc_pc;
 551 }
 552
 553 /*
 554  * This is the function called from the signal handler
 555  */
 556 gboolean
 557 mono_arch_handle_exception (void *ctx, gpointer obj, gboolean test_only)
 558 {
 559         MonoContext mctx;
 560         gboolean result;
 561
 562         mono_arch_sigctx_to_monoctx (ctx, &mctx);
 563 #ifdef DEBUG_EXCEPTIONS
 564         g_print ("mono_arch_handle_exception: pc=%p\n", (void *) mctx.sc_pc);
 565 #endif
 566         mono_handle_exception (&mctx, obj, (gpointer)mctx.sc_pc, test_only);
 567         result = TRUE;
 568
 569 #ifdef DEBUG_EXCEPTIONS
 570         g_print ("mono_arch_handle_exception: restore pc=%p\n", (void *)mctx.sc_pc);
 571 #endif
 572         /* restore the context so that returning from the signal handler
 573          * will invoke the catch clause
 574          */
 575         mono_arch_monoctx_to_sigctx (&mctx, ctx);
 576
 577         return result;
 578 }