mono/mini/tramp-x86.c

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