mono/mini/tramp-x86.c

   1 /*
   2  * tramp-x86.c: JIT trampoline code for x86
   3  *
   4  * Authors:
   5  *   Dietmar Maurer (dietmar@ximian.com)
   6  *
   7  * (C) 2001 Ximian, Inc.
   8  */
   9
  10 #include <config.h>
  11 #include <glib.h>
  12
  13 #include <mono/metadata/abi-details.h>
  14 #include <mono/metadata/appdomain.h>
  15 #include <mono/metadata/metadata-internals.h>
  16 #include <mono/metadata/marshal.h>
  17 #include <mono/metadata/tabledefs.h>
  18 #include <mono/metadata/mono-debug.h>
  19 #include <mono/metadata/mono-debug-debugger.h>
  20 #include <mono/metadata/profiler-private.h>
  21 #include <mono/metadata/gc-internals.h>
  22 #include <mono/arch/x86/x86-codegen.h>
  23
  24 #include <mono/utils/memcheck.h>
  25
  26 #include "mini.h"
  27 #include "mini-x86.h"
  28 #include "debugger-agent.h"
  29 #include "jit-icalls.h"
  30
  31 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
  32
  33 /*
  34  * mono_arch_get_unbox_trampoline:
  35  * @m: method pointer
  36  * @addr: pointer to native code for @m
  37  *
  38  * when value type methods are called through the vtable we need to unbox the
  39  * this argument. This method returns a pointer to a trampoline which does
  40  * unboxing before calling the method
  41  */
  42 gpointer
  43 mono_arch_get_unbox_trampoline (MonoMethod *m, gpointer addr)
  44 {
  45         guint8 *code, *start;
  46         int this_pos = 4, size = 16;
  47         MonoDomain *domain = mono_domain_get ();
  48         GSList *unwind_ops;
  49
  50         start = code = mono_domain_code_reserve (domain, size);
  51
  52         unwind_ops = mono_arch_get_cie_program ();
  53
  54         x86_alu_membase_imm (code, X86_ADD, X86_ESP, this_pos, sizeof (MonoObject));
  55         x86_jump_code (code, addr);
  56         g_assert ((code - start) < size);
  57
  58         mono_profiler_code_buffer_new (start, code - start, MONO_PROFILER_CODE_BUFFER_UNBOX_TRAMPOLINE, m);
  59
  60         mono_tramp_info_register (mono_tramp_info_create (NULL, start, code - start, NULL, unwind_ops), domain);
  61
  62         return start;
  63 }
  64
  65 gpointer
  66 mono_arch_get_static_rgctx_trampoline (MonoMethod *m, MonoMethodRuntimeGenericContext *mrgctx, gpointer addr)
  67 {
  68         guint8 *code, *start;
  69         int buf_len;
  70         GSList *unwind_ops;
  71
  72         MonoDomain *domain = mono_domain_get ();
  73
  74         buf_len = 10;
  75
  76         start = code = mono_domain_code_reserve (domain, buf_len);
  77
  78         unwind_ops = mono_arch_get_cie_program ();
  79
  80         x86_mov_reg_imm (code, MONO_ARCH_RGCTX_REG, mrgctx);
  81         x86_jump_code (code, addr);
  82         g_assert ((code - start) <= buf_len);
  83
  84         mono_arch_flush_icache (start, code - start);
  85         mono_profiler_code_buffer_new (start, code - start, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL);
  86
  87         mono_tramp_info_register (mono_tramp_info_create (NULL, start, code - start, NULL, unwind_ops), domain);
  88
  89         return start;
  90 }
  91
  92 void
  93 mono_arch_patch_callsite (guint8 *method_start, guint8 *orig_code, guint8 *addr)
  94 {
  95         guint8 *code;
  96         guint8 buf [8];
  97         gboolean can_write = mono_breakpoint_clean_code (method_start, orig_code, 8, buf, sizeof (buf));
  98
  99         code = buf + 8;
 100
 101         /* go to the start of the call instruction
 102          *
 103          * address_byte = (m << 6) | (o << 3) | reg
 104          * call opcode: 0xff address_byte displacement
 105          * 0xff m=1,o=2 imm8
 106          * 0xff m=2,o=2 imm32
 107          */
 108         code -= 6;
 109         orig_code -= 6;
 110         if (code [1] == 0xe8) {
 111                 if (can_write) {
 112                         InterlockedExchange ((gint32*)(orig_code + 2), (guint)addr - ((guint)orig_code + 1) - 5);
 113
 114                         /* Tell valgrind to recompile the patched code */
 115                         VALGRIND_DISCARD_TRANSLATIONS (orig_code + 2, 4);
 116                 }
 117         } else if (code [1] == 0xe9) {
 118                 /* A PLT entry: jmp <DISP> */
 119                 if (can_write)
 120                         InterlockedExchange ((gint32*)(orig_code + 2), (guint)addr - ((guint)orig_code + 1) - 5);
 121         } else {
 122                 printf ("Invalid trampoline sequence: %x %x %x %x %x %x %x\n", code [0], code [1], code [2], code [3],
 123                                 code [4], code [5], code [6]);
 124                 g_assert_not_reached ();
 125         }
 126 }
 127
 128 void
 129 mono_arch_patch_plt_entry (guint8 *code, gpointer *got, mgreg_t *regs, guint8 *addr)
 130 {
 131         guint32 offset;
 132
 133         /* Patch the jump table entry used by the plt entry */
 134
 135         /* A PLT entry: jmp *<DISP>(%ebx) */
 136         g_assert (code [0] == 0xff);
 137         g_assert (code [1] == 0xa3);
 138
 139         offset = *(guint32*)(code + 2);
 140         if (!got)
 141                 got = (gpointer*)(gsize) regs [MONO_ARCH_GOT_REG];
 142         *(guint8**)((guint8*)got + offset) = addr;
 143 }
 144
 145 static gpointer
 146 get_vcall_slot (guint8 *code, mgreg_t *regs, int *displacement)
 147 {
 148         const int kBufSize = 8;
 149         guint8 buf [64];
 150         guint8 reg = 0;
 151         gint32 disp = 0;
 152
 153         mono_breakpoint_clean_code (NULL, code, kBufSize, buf, kBufSize);
 154         code = buf + 8;
 155
 156         *displacement = 0;
 157
 158         if ((code [0] == 0xff) && ((code [1] & 0x18) == 0x10) && ((code [1] >> 6) == 2)) {
 159                 reg = code [1] & 0x07;
 160                 disp = *((gint32*)(code + 2));
 161         } else {
 162                 g_assert_not_reached ();
 163                 return NULL;
 164         }
 165
 166         *displacement = disp;
 167         return (gpointer)regs [reg];
 168 }
 169
 170 static gpointer*
 171 get_vcall_slot_addr (guint8* code, mgreg_t *regs)
 172 {
 173         gpointer vt;
 174         int displacement;
 175         vt = get_vcall_slot (code, regs, &displacement);
 176         if (!vt)
 177                 return NULL;
 178         return (gpointer*)((char*)vt + displacement);
 179 }
 180
 181 guchar*
 182 mono_arch_create_generic_trampoline (MonoTrampolineType tramp_type, MonoTrampInfo **info, gboolean aot)
 183 {
 184         char *tramp_name;
 185         guint8 *buf, *code, *tramp, *br_ex_check;
 186         GSList *unwind_ops = NULL;
 187         MonoJumpInfo *ji = NULL;
 188         int i, offset, frame_size, regarray_offset, lmf_offset, caller_ip_offset, arg_offset;
 189         int cfa_offset; /* cfa = cfa_reg + cfa_offset */
 190
 191         code = buf = mono_global_codeman_reserve (256);
 192
 193         /* Note that there is a single argument to the trampoline
 194          * and it is stored at: esp + pushed_args * sizeof (gpointer)
 195          * the ret address is at: esp + (pushed_args + 1) * sizeof (gpointer)
 196          */
 197
 198         /* Compute frame offsets relative to the frame pointer %ebp */
 199         arg_offset = sizeof (mgreg_t);
 200         caller_ip_offset = 2 * sizeof (mgreg_t);
 201         offset = 0;
 202         offset += sizeof (MonoLMF);
 203         lmf_offset = -offset;
 204         offset += X86_NREG * sizeof (mgreg_t);
 205         regarray_offset = -offset;
 206         /* Argument area */
 207         offset += 4 * sizeof (mgreg_t);
 208         frame_size = ALIGN_TO (offset, MONO_ARCH_FRAME_ALIGNMENT);
 209
 210         /* ret addr and arg are on the stack */
 211         cfa_offset = 2 * sizeof (mgreg_t);
 212         mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, cfa_offset);
 213         // IP saved at CFA - 4
 214         mono_add_unwind_op_offset (unwind_ops, code, buf, X86_NREG, -4);
 215
 216         /* Allocate frame */
 217         x86_push_reg (code, X86_EBP);
 218         cfa_offset += sizeof (mgreg_t);
 219         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 220         mono_add_unwind_op_offset (unwind_ops, code, buf, X86_EBP, -cfa_offset);
 221
 222         x86_mov_reg_reg (code, X86_EBP, X86_ESP, sizeof (mgreg_t));
 223         mono_add_unwind_op_def_cfa_reg (unwind_ops, code, buf, X86_EBP);
 224
 225         /* There are three words on the stack, adding + 4 aligns the stack to 16, which is needed on osx */
 226         x86_alu_reg_imm (code, X86_SUB, X86_ESP, frame_size + sizeof (mgreg_t));
 227
 228         /* Save all registers */
 229         for (i = X86_EAX; i <= X86_EDI; ++i) {
 230                 int reg = i;
 231
 232                 if (i == X86_EBP) {
 233                         /* Save original ebp */
 234                         /* EAX is already saved */
 235                         x86_mov_reg_membase (code, X86_EAX, X86_EBP, 0, sizeof (mgreg_t));
 236                         reg = X86_EAX;
 237                 } else if (i == X86_ESP) {
 238                         /* Save original esp */
 239                         /* EAX is already saved */
 240                         x86_mov_reg_reg (code, X86_EAX, X86_EBP, sizeof (mgreg_t));
 241                         /* Saved ebp + trampoline arg + return addr */
 242                         x86_alu_reg_imm (code, X86_ADD, X86_EAX, 3 * sizeof (mgreg_t));
 243                         reg = X86_EAX;
 244                 }
 245                 x86_mov_membase_reg (code, X86_EBP, regarray_offset + (i * sizeof (mgreg_t)), reg, sizeof (mgreg_t));
 246         }
 247
 248         /* Setup LMF */
 249         /* eip */
 250         if (tramp_type == MONO_TRAMPOLINE_JUMP) {
 251                 x86_mov_membase_imm (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, eip), 0, sizeof (mgreg_t));
 252         } else {
 253                 x86_mov_reg_membase (code, X86_EAX, X86_EBP, caller_ip_offset, sizeof (mgreg_t));
 254                 x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, eip), X86_EAX, sizeof (mgreg_t));
 255         }
 256         /* method */
 257         if ((tramp_type == MONO_TRAMPOLINE_JIT) || (tramp_type == MONO_TRAMPOLINE_JUMP)) {
 258                 x86_mov_reg_membase (code, X86_EAX, X86_EBP, arg_offset, sizeof (mgreg_t));
 259                 x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, method), X86_EAX, sizeof (mgreg_t));
 260         } else {
 261                 x86_mov_membase_imm (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, method), 0, sizeof (mgreg_t));
 262         }
 263         /* esp */
 264         x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_ESP * sizeof (mgreg_t)), sizeof (mgreg_t));
 265         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, esp), X86_EAX, sizeof (mgreg_t));
 266         /* callee save registers */
 267         x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_EBX * sizeof (mgreg_t)), sizeof (mgreg_t));
 268         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, ebx), X86_EAX, sizeof (mgreg_t));
 269         x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_EDI * sizeof (mgreg_t)), sizeof (mgreg_t));
 270         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, edi), X86_EAX, sizeof (mgreg_t));
 271         x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_ESI * sizeof (mgreg_t)), sizeof (mgreg_t));
 272         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, esi), X86_EAX, sizeof (mgreg_t));
 273         x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_EBP * sizeof (mgreg_t)), sizeof (mgreg_t));
 274         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, ebp), X86_EAX, sizeof (mgreg_t));
 275
 276         /* Push LMF */
 277         /* get the address of lmf for the current thread */
 278         if (aot) {
 279                 code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_get_lmf_addr");
 280                 x86_call_reg (code, X86_EAX);
 281         } else {
 282                 x86_call_code (code, mono_get_lmf_addr);
 283         }
 284         /* lmf->lmf_addr = lmf_addr (%eax) */
 285         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, lmf_addr), X86_EAX, sizeof (mgreg_t));
 286         /* lmf->previous_lmf = *(lmf_addr) */
 287         x86_mov_reg_membase (code, X86_ECX, X86_EAX, 0, sizeof (mgreg_t));
 288         /* Signal to mono_arch_unwind_frame () that this is a trampoline frame */
 289         x86_alu_reg_imm (code, X86_ADD, X86_ECX, 1);
 290         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, previous_lmf), X86_ECX, sizeof (mgreg_t));
 291         /* *lmf_addr = lmf */
 292         x86_lea_membase (code, X86_ECX, X86_EBP, lmf_offset);
 293         x86_mov_membase_reg (code, X86_EAX, 0, X86_ECX, sizeof (mgreg_t));
 294
 295         /* Call trampoline function */
 296         /* Arg 1 - registers */
 297         x86_lea_membase (code, X86_EAX, X86_EBP, regarray_offset);
 298         x86_mov_membase_reg (code, X86_ESP, (0 * sizeof (mgreg_t)), X86_EAX, sizeof (mgreg_t));
 299         /* Arg2 - calling code */
 300         if (tramp_type == MONO_TRAMPOLINE_JUMP) {
 301                 x86_mov_membase_imm (code, X86_ESP, (1 * sizeof (mgreg_t)), 0, sizeof (mgreg_t));
 302         } else {
 303                 x86_mov_reg_membase (code, X86_EAX, X86_EBP, caller_ip_offset, sizeof (mgreg_t));
 304                 x86_mov_membase_reg (code, X86_ESP, (1 * sizeof (mgreg_t)), X86_EAX, sizeof (mgreg_t));
 305         }
 306         /* Arg3 - trampoline argument */
 307         x86_mov_reg_membase (code, X86_EAX, X86_EBP, arg_offset, sizeof (mgreg_t));
 308         x86_mov_membase_reg (code, X86_ESP, (2 * sizeof (mgreg_t)), X86_EAX, sizeof (mgreg_t));
 309         /* Arg4 - trampoline address */
 310         // FIXME:
 311         x86_mov_membase_imm (code, X86_ESP, (3 * sizeof (mgreg_t)), 0, sizeof (mgreg_t));
 312
 313 #ifdef __APPLE__
 314         /* check the stack is aligned after the ret ip is pushed */
 315         /*
 316         x86_mov_reg_reg (code, X86_EDX, X86_ESP, 4);
 317         x86_alu_reg_imm (code, X86_AND, X86_EDX, 15);
 318         x86_alu_reg_imm (code, X86_CMP, X86_EDX, 0);
 319         x86_branch_disp (code, X86_CC_Z, 3, FALSE);
 320         x86_breakpoint (code);
 321         */
 322 #endif
 323
 324         if (aot) {
 325                 char *icall_name = g_strdup_printf ("trampoline_func_%d", tramp_type);
 326                 code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, icall_name);
 327                 x86_call_reg (code, X86_EAX);
 328         } else {
 329                 tramp = (guint8*)mono_get_trampoline_func (tramp_type);
 330                 x86_call_code (code, tramp);
 331         }
 332
 333         /*
 334          * Overwrite the trampoline argument with the address we need to jump to,
 335          * to free %eax.
 336          */
 337         x86_mov_membase_reg (code, X86_EBP, arg_offset, X86_EAX, 4);
 338
 339         /* Restore LMF */
 340         x86_mov_reg_membase (code, X86_EAX, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, lmf_addr), sizeof (mgreg_t));
 341         x86_mov_reg_membase (code, X86_ECX, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, previous_lmf), sizeof (mgreg_t));
 342         x86_alu_reg_imm (code, X86_SUB, X86_ECX, 1);
 343         x86_mov_membase_reg (code, X86_EAX, 0, X86_ECX, sizeof (mgreg_t));
 344
 345         /* Check for interruptions */
 346         if (aot) {
 347                 code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_thread_force_interruption_checkpoint_noraise");
 348                 x86_call_reg (code, X86_EAX);
 349         } else {
 350                 x86_call_code (code, (guint8*)mono_thread_force_interruption_checkpoint_noraise);
 351         }
 352
 353         x86_test_reg_reg (code, X86_EAX, X86_EAX);
 354         br_ex_check = code;
 355         x86_branch8 (code, X86_CC_Z, -1, 1);
 356
 357         /*
 358          * Exception case:
 359          * We have an exception we want to throw in the caller's frame, so pop
 360          * the trampoline frame and throw from the caller.
 361          */
 362         x86_leave (code);
 363         /*
 364          * The exception is in eax.
 365          * We are calling the throw trampoline used by OP_THROW, so we have to setup the
 366          * stack to look the same.
 367          * The stack contains the ret addr, and the trampoline argument, the throw trampoline
 368          * expects it to contain the ret addr and the exception. It also needs to be aligned
 369          * after the exception is pushed.
 370          */
 371         /* Align stack */
 372         x86_push_reg (code, X86_EAX);
 373         /* Push the exception */
 374         x86_push_reg (code, X86_EAX);
 375         //x86_breakpoint (code);
 376         /* Push the original return value */
 377         x86_push_membase (code, X86_ESP, 3 * 4);
 378         /*
 379          * EH is initialized after trampolines, so get the address of the variable
 380          * which contains throw_exception, and load it from there.
 381          */
 382         if (aot) {
 383                 /* Not really a jit icall */
 384                 code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, "throw_exception_addr");
 385         } else {
 386                 x86_mov_reg_imm (code, X86_ECX, (guint8*)mono_get_throw_exception_addr ());
 387         }
 388         x86_mov_reg_membase (code, X86_ECX, X86_ECX, 0, sizeof(gpointer));
 389         x86_jump_reg (code, X86_ECX);
 390
 391         /* Normal case */
 392         mono_x86_patch (br_ex_check, code);
 393
 394         /* Restore registers */
 395         for (i = X86_EAX; i <= X86_EDI; ++i) {
 396                 if (i == X86_ESP || i == X86_EBP)
 397                         continue;
 398                 if (i == X86_EAX && !((tramp_type == MONO_TRAMPOLINE_RESTORE_STACK_PROT) || (tramp_type == MONO_TRAMPOLINE_AOT_PLT)))
 399                         continue;
 400                 x86_mov_reg_membase (code, i, X86_EBP, regarray_offset + (i * 4), 4);
 401         }
 402
 403         /* Restore frame */
 404         x86_leave (code);
 405         cfa_offset -= sizeof (mgreg_t);
 406         mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, cfa_offset);
 407         mono_add_unwind_op_same_value (unwind_ops, code, buf, X86_EBP);
 408
 409         if (MONO_TRAMPOLINE_TYPE_MUST_RETURN (tramp_type)) {
 410                 /* Load the value returned by the trampoline */
 411                 x86_mov_reg_membase (code, X86_EAX, X86_ESP, 0, 4);
 412                 /* The trampoline returns normally, pop the trampoline argument */
 413                 x86_alu_reg_imm (code, X86_ADD, X86_ESP, 4);
 414                 cfa_offset -= sizeof (mgreg_t);
 415                 mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 416                 x86_ret (code);
 417         } else {
 418                 /* The trampoline argument is at the top of the stack, and it contains the address we need to branch to */
 419                 if (tramp_type == MONO_TRAMPOLINE_HANDLER_BLOCK_GUARD) {
 420                         x86_pop_reg (code, X86_EAX);
 421                         cfa_offset -= sizeof (mgreg_t);
 422                         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 423                         x86_alu_reg_imm (code, X86_ADD, X86_ESP, 0x8);
 424                         x86_jump_reg (code, X86_EAX);
 425                 } else {
 426                         x86_ret (code);
 427                 }
 428         }
 429
 430         g_assert ((code - buf) <= 256);
 431         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_HELPER, NULL);
 432
 433         tramp_name = mono_get_generic_trampoline_name (tramp_type);
 434         *info = mono_tramp_info_create (tramp_name, buf, code - buf, ji, unwind_ops);
 435         g_free (tramp_name);
 436
 437         return buf;
 438 }
 439
 440 #define TRAMPOLINE_SIZE 10
 441
 442 gpointer
 443 mono_arch_create_specific_trampoline (gpointer arg1, MonoTrampolineType tramp_type, MonoDomain *domain, guint32 *code_len)
 444 {
 445         guint8 *code, *buf, *tramp;
 446
 447         tramp = mono_get_trampoline_code (tramp_type);
 448
 449         code = buf = mono_domain_code_reserve_align (domain, TRAMPOLINE_SIZE, 4);
 450
 451         x86_push_imm (buf, arg1);
 452         x86_jump_code (buf, tramp);
 453         g_assert ((buf - code) <= TRAMPOLINE_SIZE);
 454
 455         mono_arch_flush_icache (code, buf - code);
 456         mono_profiler_code_buffer_new (code, buf - code, MONO_PROFILER_CODE_BUFFER_SPECIFIC_TRAMPOLINE, mono_get_generic_trampoline_simple_name (tramp_type));
 457
 458         if (code_len)
 459                 *code_len = buf - code;
 460
 461         return code;
 462 }
 463
 464 gpointer
 465 mono_arch_create_rgctx_lazy_fetch_trampoline (guint32 slot, MonoTrampInfo **info, gboolean aot)
 466 {
 467         guint8 *tramp;
 468         guint8 *code, *buf;
 469         guint8 **rgctx_null_jumps;
 470         int tramp_size;
 471         int depth, index;
 472         int i;
 473         gboolean mrgctx;
 474         MonoJumpInfo *ji = NULL;
 475         GSList *unwind_ops = NULL;
 476
 477         unwind_ops = mono_arch_get_cie_program ();
 478
 479         mrgctx = MONO_RGCTX_SLOT_IS_MRGCTX (slot);
 480         index = MONO_RGCTX_SLOT_INDEX (slot);
 481         if (mrgctx)
 482                 index += MONO_SIZEOF_METHOD_RUNTIME_GENERIC_CONTEXT / sizeof (gpointer);
 483         for (depth = 0; ; ++depth) {
 484                 int size = mono_class_rgctx_get_array_size (depth, mrgctx);
 485
 486                 if (index < size - 1)
 487                         break;
 488                 index -= size - 1;
 489         }
 490
 491         tramp_size = (aot ? 64 : 36) + 6 * depth;
 492
 493         code = buf = mono_global_codeman_reserve (tramp_size);
 494
 495         rgctx_null_jumps = g_malloc (sizeof (guint8*) * (depth + 2));
 496
 497         /* load vtable/mrgctx ptr */
 498         x86_mov_reg_membase (code, X86_EAX, X86_ESP, 4, 4);
 499         if (!mrgctx) {
 500                 /* load rgctx ptr from vtable */
 501                 x86_mov_reg_membase (code, X86_EAX, X86_EAX, MONO_STRUCT_OFFSET (MonoVTable, runtime_generic_context), 4);
 502                 /* is the rgctx ptr null? */
 503                 x86_test_reg_reg (code, X86_EAX, X86_EAX);
 504                 /* if yes, jump to actual trampoline */
 505                 rgctx_null_jumps [0] = code;
 506                 x86_branch8 (code, X86_CC_Z, -1, 1);
 507         }
 508
 509         for (i = 0; i < depth; ++i) {
 510                 /* load ptr to next array */
 511                 if (mrgctx && i == 0)
 512                         x86_mov_reg_membase (code, X86_EAX, X86_EAX, MONO_SIZEOF_METHOD_RUNTIME_GENERIC_CONTEXT, 4);
 513                 else
 514                         x86_mov_reg_membase (code, X86_EAX, X86_EAX, 0, 4);
 515                 /* is the ptr null? */
 516                 x86_test_reg_reg (code, X86_EAX, X86_EAX);
 517                 /* if yes, jump to actual trampoline */
 518                 rgctx_null_jumps [i + 1] = code;
 519                 x86_branch8 (code, X86_CC_Z, -1, 1);
 520         }
 521
 522         /* fetch slot */
 523         x86_mov_reg_membase (code, X86_EAX, X86_EAX, sizeof (gpointer) * (index + 1), 4);
 524         /* is the slot null? */
 525         x86_test_reg_reg (code, X86_EAX, X86_EAX);
 526         /* if yes, jump to actual trampoline */
 527         rgctx_null_jumps [depth + 1] = code;
 528         x86_branch8 (code, X86_CC_Z, -1, 1);
 529         /* otherwise return */
 530         x86_ret (code);
 531
 532         for (i = mrgctx ? 1 : 0; i <= depth + 1; ++i)
 533                 x86_patch (rgctx_null_jumps [i], code);
 534
 535         g_free (rgctx_null_jumps);
 536
 537         x86_mov_reg_membase (code, MONO_ARCH_VTABLE_REG, X86_ESP, 4, 4);
 538
 539         if (aot) {
 540                 code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, g_strdup_printf ("specific_trampoline_lazy_fetch_%u", slot));
 541                 x86_jump_reg (code, X86_EAX);
 542         } else {
 543                 tramp = mono_arch_create_specific_trampoline (GUINT_TO_POINTER (slot), MONO_TRAMPOLINE_RGCTX_LAZY_FETCH, mono_get_root_domain (), NULL);
 544
 545                 /* jump to the actual trampoline */
 546                 x86_jump_code (code, tramp);
 547         }
 548
 549         mono_arch_flush_icache (buf, code - buf);
 550         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL);
 551
 552         g_assert (code - buf <= tramp_size);
 553
 554         char *name = mono_get_rgctx_fetch_trampoline_name (slot);
 555         *info = mono_tramp_info_create (name, buf, code - buf, ji, unwind_ops);
 556         g_free (name);
 557
 558         return buf;
 559 }
 560
 561 /*
 562  * mono_arch_create_general_rgctx_lazy_fetch_trampoline:
 563  *
 564  *   This is a general variant of the rgctx fetch trampolines. It receives a pointer to gpointer[2] in the rgctx reg. The first entry contains the slot, the second
 565  * the trampoline to call if the slot is not filled.
 566  */
 567 gpointer
 568 mono_arch_create_general_rgctx_lazy_fetch_trampoline (MonoTrampInfo **info, gboolean aot)
 569 {
 570         guint8 *code, *buf;
 571         int tramp_size;
 572         MonoJumpInfo *ji = NULL;
 573         GSList *unwind_ops = NULL;
 574
 575         g_assert (aot);
 576
 577         unwind_ops = mono_arch_get_cie_program ();
 578
 579         tramp_size = 64;
 580
 581         code = buf = mono_global_codeman_reserve (tramp_size);
 582
 583         // FIXME: Currently, we always go to the slow path.
 584
 585         /* Load trampoline addr */
 586         x86_mov_reg_membase (code, X86_EAX, MONO_ARCH_RGCTX_REG, 4, 4);
 587         /* Load mrgctx/vtable */
 588         x86_mov_reg_membase (code, MONO_ARCH_VTABLE_REG, X86_ESP, 4, 4);
 589
 590         x86_jump_reg (code, X86_EAX);
 591
 592         mono_arch_flush_icache (buf, code - buf);
 593         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL);
 594
 595         g_assert (code - buf <= tramp_size);
 596
 597         *info = mono_tramp_info_create ("rgctx_fetch_trampoline_general", buf, code - buf, ji, unwind_ops);
 598
 599         return buf;
 600 }
 601
 602 void
 603 mono_arch_invalidate_method (MonoJitInfo *ji, void *func, gpointer func_arg)
 604 {
 605         /* FIXME: This is not thread safe */
 606         guint8 *code = ji->code_start;
 607
 608         x86_push_imm (code, func_arg);
 609         x86_call_code (code, (guint8*)func);
 610 }
 611
 612 static gpointer
 613 handler_block_trampoline_helper (void)
 614 {
 615         MonoJitTlsData *jit_tls = mono_native_tls_get_value (mono_jit_tls_id);
 616         return jit_tls->handler_block_return_address;
 617 }
 618
 619 gpointer
 620 mono_arch_create_handler_block_trampoline (MonoTrampInfo **info, gboolean aot)
 621 {
 622         guint8 *tramp = mono_get_trampoline_code (MONO_TRAMPOLINE_HANDLER_BLOCK_GUARD);
 623         guint8 *code, *buf;
 624         int tramp_size = 64;
 625         MonoJumpInfo *ji = NULL;
 626         int cfa_offset;
 627         GSList *unwind_ops = NULL;
 628
 629         g_assert (!aot);
 630
 631         code = buf = mono_global_codeman_reserve (tramp_size);
 632
 633         unwind_ops = mono_arch_get_cie_program ();
 634         cfa_offset = sizeof (mgreg_t);
 635         /*
 636         This trampoline restore the call chain of the handler block then jumps into the code that deals with it.
 637         */
 638
 639         /*
 640          * We are in a method frame after the call emitted by OP_CALL_HANDLER.
 641          */
 642
 643         if (mono_get_jit_tls_offset () != -1) {
 644                 code = mono_x86_emit_tls_get (code, X86_EAX, mono_get_jit_tls_offset ());
 645                 x86_mov_reg_membase (code, X86_EAX, X86_EAX, MONO_STRUCT_OFFSET (MonoJitTlsData, handler_block_return_address), 4);
 646         } else {
 647                 /*Slow path uses a c helper*/
 648                 x86_call_code (code, handler_block_trampoline_helper);
 649         }
 650         /* Simulate a call */
 651         /*Fix stack alignment*/
 652         x86_alu_reg_imm (code, X86_SUB, X86_ESP, 0x4);
 653         cfa_offset += sizeof (mgreg_t);
 654         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 655
 656         /* This is the address the trampoline will return to */
 657         x86_push_reg (code, X86_EAX);
 658         cfa_offset += sizeof (mgreg_t);
 659         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 660
 661         /* Dummy trampoline argument, since we call the generic trampoline directly */
 662         x86_push_imm (code, 0);
 663         cfa_offset += sizeof (mgreg_t);
 664         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 665         x86_jump_code (code, tramp);
 666
 667         mono_arch_flush_icache (buf, code - buf);
 668         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_HELPER, NULL);
 669         g_assert (code - buf <= tramp_size);
 670
 671         *info = mono_tramp_info_create ("handler_block_trampoline", buf, code - buf, ji, unwind_ops);
 672
 673         return buf;
 674 }
 675
 676 guint8*
 677 mono_arch_get_call_target (guint8 *code)
 678 {
 679         if (code [-5] == 0xe8) {
 680                 gint32 disp = *(gint32*)(code - 4);
 681                 guint8 *target = code + disp;
 682
 683                 return target;
 684         } else {
 685                 return NULL;
 686         }
 687 }
 688
 689 guint32
 690 mono_arch_get_plt_info_offset (guint8 *plt_entry, mgreg_t *regs, guint8 *code)
 691 {
 692         return *(guint32*)(plt_entry + 6);
 693 }
 694
 695 /*
 696  * mono_arch_get_gsharedvt_arg_trampoline:
 697  *
 698  *   Return a trampoline which passes ARG to the gsharedvt in/out trampoline ADDR.
 699  */
 700 gpointer
 701 mono_arch_get_gsharedvt_arg_trampoline (MonoDomain *domain, gpointer arg, gpointer addr)
 702 {
 703         guint8 *code, *start;
 704         int buf_len;
 705         GSList *unwind_ops;
 706
 707
 708         buf_len = 10;
 709
 710         start = code = mono_domain_code_reserve (domain, buf_len);
 711
 712         unwind_ops = mono_arch_get_cie_program ();
 713
 714         x86_mov_reg_imm (code, X86_EAX, arg);
 715         x86_jump_code (code, addr);
 716         g_assert ((code - start) <= buf_len);
 717
 718         mono_arch_flush_icache (start, code - start);
 719         mono_profiler_code_buffer_new (start, code - start, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL);
 720
 721         mono_tramp_info_register (mono_tramp_info_create (NULL, start, code - start, NULL, unwind_ops), domain);
 722
 723         return start;
 724 }
 725
 726 /*
 727  * mono_arch_create_sdb_trampoline:
 728  *
 729  *   Return a trampoline which captures the current context, passes it to
 730  * debugger_agent_single_step_from_context ()/debugger_agent_breakpoint_from_context (),
 731  * then restores the (potentially changed) context.
 732  */
 733 guint8*
 734 mono_arch_create_sdb_trampoline (gboolean single_step, MonoTrampInfo **info, gboolean aot)
 735 {
 736         int tramp_size = 256;
 737         int framesize, ctx_offset, cfa_offset;
 738         guint8 *code, *buf;
 739         GSList *unwind_ops = NULL;
 740         MonoJumpInfo *ji = NULL;
 741
 742         code = buf = mono_global_codeman_reserve (tramp_size);
 743
 744         framesize = 0;
 745
 746         /* Argument area */
 747         framesize += sizeof (mgreg_t);
 748
 749         framesize = ALIGN_TO (framesize, 8);
 750         ctx_offset = framesize;
 751         framesize += sizeof (MonoContext);
 752
 753         framesize = ALIGN_TO (framesize, MONO_ARCH_FRAME_ALIGNMENT);
 754
 755         // CFA = sp + 4
 756         cfa_offset = 4;
 757         mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, 4);
 758         // IP saved at CFA - 4
 759         mono_add_unwind_op_offset (unwind_ops, code, buf, X86_NREG, -cfa_offset);
 760
 761         x86_push_reg (code, X86_EBP);
 762         cfa_offset += sizeof(mgreg_t);
 763         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 764         mono_add_unwind_op_offset (unwind_ops, code, buf, X86_EBP, - cfa_offset);
 765
 766         x86_mov_reg_reg (code, X86_EBP, X86_ESP, sizeof(mgreg_t));
 767         mono_add_unwind_op_def_cfa_reg (unwind_ops, code, buf, X86_EBP);
 768         /* The + 8 makes the stack aligned */
 769         x86_alu_reg_imm (code, X86_SUB, X86_ESP, framesize + 8);
 770
 771         /* Initialize a MonoContext structure on the stack */
 772         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eax), X86_EAX, sizeof (mgreg_t));
 773         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebx), X86_EBX, sizeof (mgreg_t));
 774         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ecx), X86_ECX, sizeof (mgreg_t));
 775         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edx), X86_EDX, sizeof (mgreg_t));
 776         x86_mov_reg_membase (code, X86_EAX, X86_EBP, 0, sizeof (mgreg_t));
 777         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebp), X86_EAX, sizeof (mgreg_t));
 778         x86_mov_reg_reg (code, X86_EAX, X86_EBP, sizeof (mgreg_t));
 779         x86_alu_reg_imm (code, X86_ADD, X86_EAX, cfa_offset);
 780         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, esp), X86_ESP, sizeof (mgreg_t));
 781         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, esi), X86_ESI, sizeof (mgreg_t));
 782         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edi), X86_EDI, sizeof (mgreg_t));
 783         x86_mov_reg_membase (code, X86_EAX, X86_EBP, 4, sizeof (mgreg_t));
 784         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eip), X86_EAX, sizeof (mgreg_t));
 785
 786         /* Call the single step/breakpoint function in sdb */
 787         x86_lea_membase (code, X86_EAX, X86_ESP, ctx_offset);
 788         x86_mov_membase_reg (code, X86_ESP, 0, X86_EAX, sizeof (mgreg_t));
 789
 790         if (aot) {
 791                 x86_breakpoint (code);
 792         } else {
 793                 if (single_step)
 794                         x86_call_code (code, debugger_agent_single_step_from_context);
 795                 else
 796                         x86_call_code (code, debugger_agent_breakpoint_from_context);
 797         }
 798
 799         /* Restore registers from ctx */
 800         /* Overwrite the saved ebp */
 801         x86_mov_reg_membase (code, X86_EAX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebp), sizeof (mgreg_t));
 802         x86_mov_membase_reg (code, X86_EBP, 0, X86_EAX, sizeof (mgreg_t));
 803         /* Overwrite saved eip */
 804         x86_mov_reg_membase (code, X86_EAX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eip), sizeof (mgreg_t));
 805         x86_mov_membase_reg (code, X86_EBP, 4, X86_EAX, sizeof (mgreg_t));
 806         x86_mov_reg_membase (code, X86_EAX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eax), sizeof (mgreg_t));
 807         x86_mov_reg_membase (code, X86_EBX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebx), sizeof (mgreg_t));
 808         x86_mov_reg_membase (code, X86_ECX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ecx), sizeof (mgreg_t));
 809         x86_mov_reg_membase (code, X86_EDX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edx), sizeof (mgreg_t));
 810         x86_mov_reg_membase (code, X86_ESI, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, esi), sizeof (mgreg_t));
 811         x86_mov_reg_membase (code, X86_EDI, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edi), sizeof (mgreg_t));
 812
 813         x86_leave (code);
 814         cfa_offset -= sizeof (mgreg_t);
 815         mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, cfa_offset);
 816         x86_ret (code);
 817
 818         mono_arch_flush_icache (code, code - buf);
 819         g_assert (code - buf <= tramp_size);
 820
 821         const char *tramp_name = single_step ? "sdb_single_step_trampoline" : "sdb_breakpoint_trampoline";
 822         *info = mono_tramp_info_create (tramp_name, buf, code - buf, ji, unwind_ops);
 823
 824         return buf;
 825 }
 826