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 "mini-runtime.h"
  28 #include "debugger-agent.h"
  29 #include "jit-icalls.h"
  30
  31 /*
  32  * mono_arch_get_unbox_trampoline:
  33  * @m: method pointer
  34  * @addr: pointer to native code for @m
  35  *
  36  * when value type methods are called through the vtable we need to unbox the
  37  * this argument. This method returns a pointer to a trampoline which does
  38  * unboxing before calling the method
  39  */
  40 gpointer
  41 mono_arch_get_unbox_trampoline (MonoMethod *m, gpointer addr)
  42 {
  43         guint8 *code, *start;
  44         int this_pos = 4, size = 16;
  45         MonoDomain *domain = mono_domain_get ();
  46         GSList *unwind_ops;
  47
  48         start = code = mono_domain_code_reserve (domain, size);
  49
  50         unwind_ops = mono_arch_get_cie_program ();
  51
  52         x86_alu_membase_imm (code, X86_ADD, X86_ESP, this_pos, MONO_ABI_SIZEOF (MonoObject));
  53         x86_jump_code (code, addr);
  54         g_assert ((code - start) < size);
  55
  56         MONO_PROFILER_RAISE (jit_code_buffer, (start, code - start, MONO_PROFILER_CODE_BUFFER_UNBOX_TRAMPOLINE, m));
  57
  58         mono_tramp_info_register (mono_tramp_info_create (NULL, start, code - start, NULL, unwind_ops), domain);
  59
  60         return start;
  61 }
  62
  63 gpointer
  64 mono_arch_get_static_rgctx_trampoline (gpointer arg, gpointer addr)
  65 {
  66         guint8 *code, *start;
  67         int buf_len;
  68         GSList *unwind_ops;
  69
  70         MonoDomain *domain = mono_domain_get ();
  71
  72         buf_len = 10;
  73
  74         start = code = mono_domain_code_reserve (domain, buf_len);
  75
  76         unwind_ops = mono_arch_get_cie_program ();
  77
  78         x86_mov_reg_imm (code, MONO_ARCH_RGCTX_REG, arg);
  79         x86_jump_code (code, addr);
  80         g_assert ((code - start) <= buf_len);
  81
  82         mono_arch_flush_icache (start, code - start);
  83         MONO_PROFILER_RAISE (jit_code_buffer, (start, code - start, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL));
  84
  85         mono_tramp_info_register (mono_tramp_info_create (NULL, start, code - start, NULL, unwind_ops), domain);
  86
  87         return start;
  88 }
  89
  90 void
  91 mono_arch_patch_callsite (guint8 *method_start, guint8 *orig_code, guint8 *addr)
  92 {
  93         guint8 *code;
  94         guint8 buf [8];
  95
  96         // Since method_start is retrieved from function return address (below current call/jmp to patch) there is a case when
  97         // last instruction of a function is the call (due to OP_NOT_REACHED) instruction and then directly followed by a
  98         // different method. In that case current orig_code points into next method and method_start will also point into
  99         // next method, not the method including the call to patch. For this specific case, fallback to using a method_start of NULL.
 100         gboolean can_write = mono_breakpoint_clean_code (method_start != orig_code ? method_start : NULL, orig_code, 8, buf, sizeof (buf));
 101
 102         code = buf + 8;
 103
 104         /* go to the start of the call instruction
 105          *
 106          * address_byte = (m << 6) | (o << 3) | reg
 107          * call opcode: 0xff address_byte displacement
 108          * 0xff m=1,o=2 imm8
 109          * 0xff m=2,o=2 imm32
 110          */
 111         code -= 6;
 112         orig_code -= 6;
 113         if (code [1] == 0xe8) {
 114                 if (can_write) {
 115                         mono_atomic_xchg_i32 ((gint32*)(orig_code + 2), (guint)addr - ((guint)orig_code + 1) - 5);
 116
 117                         /* Tell valgrind to recompile the patched code */
 118                         VALGRIND_DISCARD_TRANSLATIONS (orig_code + 2, 4);
 119                 }
 120         } else if (code [1] == 0xe9) {
 121                 /* A PLT entry: jmp <DISP> */
 122                 if (can_write)
 123                         mono_atomic_xchg_i32 ((gint32*)(orig_code + 2), (guint)addr - ((guint)orig_code + 1) - 5);
 124         } else {
 125                 printf ("Invalid trampoline sequence: %x %x %x %x %x %x n", code [0], code [1], code [2], code [3],
 126                                 code [4], code [5]);
 127
 128                 g_assert_not_reached ();
 129         }
 130 }
 131
 132 void
 133 mono_arch_patch_plt_entry (guint8 *code, gpointer *got, host_mgreg_t *regs, guint8 *addr)
 134 {
 135         guint32 offset;
 136
 137         /* Patch the jump table entry used by the plt entry */
 138
 139         /* A PLT entry: jmp *<DISP>(%ebx) */
 140         g_assert (code [0] == 0xff);
 141         g_assert (code [1] == 0xa3);
 142
 143         offset = *(guint32*)(code + 2);
 144         if (!got)
 145                 got = (gpointer*)(gsize) regs [MONO_ARCH_GOT_REG];
 146         *(guint8**)((guint8*)got + offset) = addr;
 147 }
 148
 149 guchar*
 150 mono_arch_create_generic_trampoline (MonoTrampolineType tramp_type, MonoTrampInfo **info, gboolean aot)
 151 {
 152         const char *tramp_name;
 153         guint8 *buf, *code, *tramp, *br_ex_check;
 154         GSList *unwind_ops = NULL;
 155         MonoJumpInfo *ji = NULL;
 156         int i, offset, frame_size, regarray_offset, lmf_offset, caller_ip_offset, arg_offset;
 157         int cfa_offset; /* cfa = cfa_reg + cfa_offset */
 158
 159         code = buf = mono_global_codeman_reserve (256);
 160
 161         /* Note that there is a single argument to the trampoline
 162          * and it is stored at: esp + pushed_args * sizeof (target_mgreg_t)
 163          * the ret address is at: esp + (pushed_args + 1) * sizeof (target_mgreg_t)
 164          */
 165
 166         /* Compute frame offsets relative to the frame pointer %ebp */
 167         arg_offset = sizeof (target_mgreg_t);
 168         caller_ip_offset = 2 * sizeof (target_mgreg_t);
 169         offset = 0;
 170         offset += sizeof (MonoLMF);
 171         lmf_offset = -offset;
 172         offset += X86_NREG * sizeof (target_mgreg_t);
 173         regarray_offset = -offset;
 174         /* Argument area */
 175         offset += 4 * sizeof (target_mgreg_t);
 176         frame_size = ALIGN_TO (offset, MONO_ARCH_FRAME_ALIGNMENT);
 177
 178         /* ret addr and arg are on the stack */
 179         cfa_offset = 2 * sizeof (target_mgreg_t);
 180         mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, cfa_offset);
 181         // IP saved at CFA - 4
 182         mono_add_unwind_op_offset (unwind_ops, code, buf, X86_NREG, -4);
 183
 184         /* Allocate frame */
 185         x86_push_reg (code, X86_EBP);
 186         cfa_offset += sizeof (target_mgreg_t);
 187         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 188         mono_add_unwind_op_offset (unwind_ops, code, buf, X86_EBP, -cfa_offset);
 189
 190         x86_mov_reg_reg (code, X86_EBP, X86_ESP);
 191         mono_add_unwind_op_def_cfa_reg (unwind_ops, code, buf, X86_EBP);
 192
 193         /* There are three words on the stack, adding + 4 aligns the stack to 16, which is needed on osx */
 194         x86_alu_reg_imm (code, X86_SUB, X86_ESP, frame_size + sizeof (target_mgreg_t));
 195
 196         /* Save all registers */
 197         for (i = X86_EAX; i <= X86_EDI; ++i) {
 198                 int reg = i;
 199
 200                 if (i == X86_EBP) {
 201                         /* Save original ebp */
 202                         /* EAX is already saved */
 203                         x86_mov_reg_membase (code, X86_EAX, X86_EBP, 0, sizeof (target_mgreg_t));
 204                         reg = X86_EAX;
 205                 } else if (i == X86_ESP) {
 206                         /* Save original esp */
 207                         /* EAX is already saved */
 208                         x86_mov_reg_reg (code, X86_EAX, X86_EBP);
 209                         /* Saved ebp + trampoline arg + return addr */
 210                         x86_alu_reg_imm (code, X86_ADD, X86_EAX, 3 * sizeof (target_mgreg_t));
 211                         reg = X86_EAX;
 212                 }
 213                 x86_mov_membase_reg (code, X86_EBP, regarray_offset + (i * sizeof (target_mgreg_t)), reg, sizeof (target_mgreg_t));
 214         }
 215
 216         /* Setup LMF */
 217         /* eip */
 218         if (tramp_type == MONO_TRAMPOLINE_JUMP) {
 219                 x86_mov_membase_imm (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, eip), 0, sizeof (target_mgreg_t));
 220         } else {
 221                 x86_mov_reg_membase (code, X86_EAX, X86_EBP, caller_ip_offset, sizeof (target_mgreg_t));
 222                 x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, eip), X86_EAX, sizeof (target_mgreg_t));
 223         }
 224         /* method */
 225         if ((tramp_type == MONO_TRAMPOLINE_JIT) || (tramp_type == MONO_TRAMPOLINE_JUMP)) {
 226                 x86_mov_reg_membase (code, X86_EAX, X86_EBP, arg_offset, sizeof (target_mgreg_t));
 227                 x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, method), X86_EAX, sizeof (target_mgreg_t));
 228         } else {
 229                 x86_mov_membase_imm (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, method), 0, sizeof (target_mgreg_t));
 230         }
 231         /* esp */
 232         x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_ESP * sizeof (target_mgreg_t)), sizeof (target_mgreg_t));
 233         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, esp), X86_EAX, sizeof (target_mgreg_t));
 234         /* callee save registers */
 235         x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_EBX * sizeof (target_mgreg_t)), sizeof (target_mgreg_t));
 236         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, ebx), X86_EAX, sizeof (target_mgreg_t));
 237         x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_EDI * sizeof (target_mgreg_t)), sizeof (target_mgreg_t));
 238         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, edi), X86_EAX, sizeof (target_mgreg_t));
 239         x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_ESI * sizeof (target_mgreg_t)), sizeof (target_mgreg_t));
 240         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, esi), X86_EAX, sizeof (target_mgreg_t));
 241         x86_mov_reg_membase (code, X86_EAX, X86_EBP, regarray_offset + (X86_EBP * sizeof (target_mgreg_t)), sizeof (target_mgreg_t));
 242         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, ebp), X86_EAX, sizeof (target_mgreg_t));
 243
 244         /* Push LMF */
 245         /* get the address of lmf for the current thread */
 246         if (aot) {
 247                 code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, GUINT_TO_POINTER (MONO_JIT_ICALL_mono_get_lmf_addr));
 248                 x86_call_reg (code, X86_EAX);
 249         } else {
 250                 x86_call_code (code, mono_get_lmf_addr);
 251         }
 252         /* lmf->lmf_addr = lmf_addr (%eax) */
 253         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, lmf_addr), X86_EAX, sizeof (target_mgreg_t));
 254         /* lmf->previous_lmf = *(lmf_addr) */
 255         x86_mov_reg_membase (code, X86_ECX, X86_EAX, 0, sizeof (target_mgreg_t));
 256         /* Signal to mono_arch_unwind_frame () that this is a trampoline frame */
 257         x86_alu_reg_imm (code, X86_ADD, X86_ECX, 1);
 258         x86_mov_membase_reg (code, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, previous_lmf), X86_ECX, sizeof (target_mgreg_t));
 259         /* *lmf_addr = lmf */
 260         x86_lea_membase (code, X86_ECX, X86_EBP, lmf_offset);
 261         x86_mov_membase_reg (code, X86_EAX, 0, X86_ECX, sizeof (target_mgreg_t));
 262
 263         /* Call trampoline function */
 264         /* Arg 1 - registers */
 265         x86_lea_membase (code, X86_EAX, X86_EBP, regarray_offset);
 266         x86_mov_membase_reg (code, X86_ESP, (0 * sizeof (target_mgreg_t)), X86_EAX, sizeof (target_mgreg_t));
 267         /* Arg2 - calling code */
 268         if (tramp_type == MONO_TRAMPOLINE_JUMP) {
 269                 x86_mov_membase_imm (code, X86_ESP, (1 * sizeof (target_mgreg_t)), 0, sizeof (target_mgreg_t));
 270         } else {
 271                 x86_mov_reg_membase (code, X86_EAX, X86_EBP, caller_ip_offset, sizeof (target_mgreg_t));
 272                 x86_mov_membase_reg (code, X86_ESP, (1 * sizeof (target_mgreg_t)), X86_EAX, sizeof (target_mgreg_t));
 273         }
 274         /* Arg3 - trampoline argument */
 275         x86_mov_reg_membase (code, X86_EAX, X86_EBP, arg_offset, sizeof (target_mgreg_t));
 276         x86_mov_membase_reg (code, X86_ESP, (2 * sizeof (target_mgreg_t)), X86_EAX, sizeof (target_mgreg_t));
 277         /* Arg4 - trampoline address */
 278         // FIXME:
 279         x86_mov_membase_imm (code, X86_ESP, (3 * sizeof (target_mgreg_t)), 0, sizeof (target_mgreg_t));
 280
 281 #ifdef __APPLE__
 282         /* check the stack is aligned after the ret ip is pushed */
 283         /*
 284         x86_mov_reg_reg (code, X86_EDX, X86_ESP);
 285         x86_alu_reg_imm (code, X86_AND, X86_EDX, 15);
 286         x86_alu_reg_imm (code, X86_CMP, X86_EDX, 0);
 287         x86_branch_disp (code, X86_CC_Z, 3, FALSE);
 288         x86_breakpoint (code);
 289         */
 290 #endif
 291
 292         if (aot) {
 293                 code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, GINT_TO_POINTER (mono_trampoline_type_to_jit_icall_id (tramp_type)));
 294                 x86_call_reg (code, X86_EAX);
 295         } else {
 296                 tramp = (guint8*)mono_get_trampoline_func (tramp_type);
 297                 x86_call_code (code, tramp);
 298         }
 299
 300         /*
 301          * Overwrite the trampoline argument with the address we need to jump to,
 302          * to free %eax.
 303          */
 304         x86_mov_membase_reg (code, X86_EBP, arg_offset, X86_EAX, 4);
 305
 306         /* Restore LMF */
 307         x86_mov_reg_membase (code, X86_EAX, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, lmf_addr), sizeof (target_mgreg_t));
 308         x86_mov_reg_membase (code, X86_ECX, X86_EBP, lmf_offset + G_STRUCT_OFFSET (MonoLMF, previous_lmf), sizeof (target_mgreg_t));
 309         x86_alu_reg_imm (code, X86_SUB, X86_ECX, 1);
 310         x86_mov_membase_reg (code, X86_EAX, 0, X86_ECX, sizeof (target_mgreg_t));
 311
 312         /* Check for interruptions */
 313         if (aot) {
 314                 code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, GUINT_TO_POINTER (MONO_JIT_ICALL_mono_thread_force_interruption_checkpoint_noraise));
 315                 x86_call_reg (code, X86_EAX);
 316         } else {
 317                 x86_call_code (code, (guint8*)mono_thread_force_interruption_checkpoint_noraise);
 318         }
 319
 320         x86_test_reg_reg (code, X86_EAX, X86_EAX);
 321         br_ex_check = code;
 322         x86_branch8 (code, X86_CC_Z, -1, 1);
 323
 324         /*
 325          * Exception case:
 326          * We have an exception we want to throw in the caller's frame, so pop
 327          * the trampoline frame and throw from the caller.
 328          */
 329         x86_leave (code);
 330         /*
 331          * The exception is in eax.
 332          * We are calling the throw trampoline used by OP_THROW, so we have to setup the
 333          * stack to look the same.
 334          * The stack contains the ret addr, and the trampoline argument, the throw trampoline
 335          * expects it to contain the ret addr and the exception. It also needs to be aligned
 336          * after the exception is pushed.
 337          */
 338         /* Align stack */
 339         x86_push_reg (code, X86_EAX);
 340         /* Push the exception */
 341         x86_push_reg (code, X86_EAX);
 342         //x86_breakpoint (code);
 343         /* Push the original return value */
 344         x86_push_membase (code, X86_ESP, 3 * 4);
 345         /*
 346          * EH is initialized after trampolines, so get the address of the variable
 347          * which contains throw_exception, and load it from there.
 348          */
 349         if (aot) {
 350                 /* Not really a jit icall */
 351                 code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, GUINT_TO_POINTER (MONO_JIT_ICALL_mono_rethrow_preserve_exception));
 352         } else {
 353                 x86_mov_reg_imm (code, X86_ECX, (guint8*)mono_get_rethrow_preserve_exception_addr ());
 354         }
 355         x86_mov_reg_membase (code, X86_ECX, X86_ECX, 0, sizeof (target_mgreg_t));
 356         x86_jump_reg (code, X86_ECX);
 357
 358         /* Normal case */
 359         mono_x86_patch (br_ex_check, code);
 360
 361         /* Restore registers */
 362         for (i = X86_EAX; i <= X86_EDI; ++i) {
 363                 if (i == X86_ESP || i == X86_EBP)
 364                         continue;
 365                 if (i == X86_EAX && tramp_type != MONO_TRAMPOLINE_AOT_PLT)
 366                         continue;
 367                 x86_mov_reg_membase (code, i, X86_EBP, regarray_offset + (i * 4), 4);
 368         }
 369
 370         /* Restore frame */
 371         x86_leave (code);
 372         cfa_offset -= sizeof (target_mgreg_t);
 373         mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, cfa_offset);
 374         mono_add_unwind_op_same_value (unwind_ops, code, buf, X86_EBP);
 375
 376         if (MONO_TRAMPOLINE_TYPE_MUST_RETURN (tramp_type)) {
 377                 /* Load the value returned by the trampoline */
 378                 x86_mov_reg_membase (code, X86_EAX, X86_ESP, 0, 4);
 379                 /* The trampoline returns normally, pop the trampoline argument */
 380                 x86_alu_reg_imm (code, X86_ADD, X86_ESP, 4);
 381                 cfa_offset -= sizeof (target_mgreg_t);
 382                 mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 383                 x86_ret (code);
 384         } else {
 385                 x86_ret (code);
 386         }
 387
 388         g_assert ((code - buf) <= 256);
 389         MONO_PROFILER_RAISE (jit_code_buffer, (buf, code - buf, MONO_PROFILER_CODE_BUFFER_HELPER, NULL));
 390
 391         tramp_name = mono_get_generic_trampoline_name (tramp_type);
 392         *info = mono_tramp_info_create (tramp_name, buf, code - buf, ji, unwind_ops);
 393
 394         return buf;
 395 }
 396
 397 #define TRAMPOLINE_SIZE 10
 398
 399 gpointer
 400 mono_arch_create_specific_trampoline (gpointer arg1, MonoTrampolineType tramp_type, MonoDomain *domain, guint32 *code_len)
 401 {
 402         guint8 *code, *buf, *tramp;
 403
 404         tramp = mono_get_trampoline_code (tramp_type);
 405
 406         code = buf = mono_domain_code_reserve_align (domain, TRAMPOLINE_SIZE, 4);
 407
 408         x86_push_imm (buf, arg1);
 409         x86_jump_code (buf, tramp);
 410         g_assert ((buf - code) <= TRAMPOLINE_SIZE);
 411
 412         mono_arch_flush_icache (code, buf - code);
 413         MONO_PROFILER_RAISE (jit_code_buffer, (code, buf - code, MONO_PROFILER_CODE_BUFFER_SPECIFIC_TRAMPOLINE, mono_get_generic_trampoline_simple_name (tramp_type)));
 414
 415         if (code_len)
 416                 *code_len = buf - code;
 417
 418         return code;
 419 }
 420
 421 gpointer
 422 mono_arch_create_rgctx_lazy_fetch_trampoline (guint32 slot, MonoTrampInfo **info, gboolean aot)
 423 {
 424         guint8 *tramp;
 425         guint8 *code, *buf;
 426         guint8 **rgctx_null_jumps;
 427         int tramp_size;
 428         int depth, index;
 429         int i;
 430         gboolean mrgctx;
 431         MonoJumpInfo *ji = NULL;
 432         GSList *unwind_ops = NULL;
 433
 434         unwind_ops = mono_arch_get_cie_program ();
 435
 436         mrgctx = MONO_RGCTX_SLOT_IS_MRGCTX (slot);
 437         index = MONO_RGCTX_SLOT_INDEX (slot);
 438         if (mrgctx)
 439                 index += MONO_SIZEOF_METHOD_RUNTIME_GENERIC_CONTEXT / sizeof (target_mgreg_t);
 440         for (depth = 0; ; ++depth) {
 441                 int size = mono_class_rgctx_get_array_size (depth, mrgctx);
 442
 443                 if (index < size - 1)
 444                         break;
 445                 index -= size - 1;
 446         }
 447
 448         tramp_size = (aot ? 64 : 36) + 6 * depth;
 449
 450         code = buf = mono_global_codeman_reserve (tramp_size);
 451
 452         rgctx_null_jumps = g_malloc (sizeof (guint8*) * (depth + 2));
 453
 454         /* load vtable/mrgctx ptr */
 455         x86_mov_reg_membase (code, X86_EAX, X86_ESP, 4, 4);
 456         if (!mrgctx) {
 457                 /* load rgctx ptr from vtable */
 458                 x86_mov_reg_membase (code, X86_EAX, X86_EAX, MONO_STRUCT_OFFSET (MonoVTable, runtime_generic_context), 4);
 459                 /* is the rgctx ptr null? */
 460                 x86_test_reg_reg (code, X86_EAX, X86_EAX);
 461                 /* if yes, jump to actual trampoline */
 462                 rgctx_null_jumps [0] = code;
 463                 x86_branch8 (code, X86_CC_Z, -1, 1);
 464         }
 465
 466         for (i = 0; i < depth; ++i) {
 467                 /* load ptr to next array */
 468                 if (mrgctx && i == 0)
 469                         x86_mov_reg_membase (code, X86_EAX, X86_EAX, MONO_SIZEOF_METHOD_RUNTIME_GENERIC_CONTEXT, 4);
 470                 else
 471                         x86_mov_reg_membase (code, X86_EAX, X86_EAX, 0, 4);
 472                 /* is the ptr null? */
 473                 x86_test_reg_reg (code, X86_EAX, X86_EAX);
 474                 /* if yes, jump to actual trampoline */
 475                 rgctx_null_jumps [i + 1] = code;
 476                 x86_branch8 (code, X86_CC_Z, -1, 1);
 477         }
 478
 479         /* fetch slot */
 480         x86_mov_reg_membase (code, X86_EAX, X86_EAX, sizeof (target_mgreg_t) * (index + 1), 4);
 481         /* is the slot null? */
 482         x86_test_reg_reg (code, X86_EAX, X86_EAX);
 483         /* if yes, jump to actual trampoline */
 484         rgctx_null_jumps [depth + 1] = code;
 485         x86_branch8 (code, X86_CC_Z, -1, 1);
 486         /* otherwise return */
 487         x86_ret (code);
 488
 489         for (i = mrgctx ? 1 : 0; i <= depth + 1; ++i)
 490                 x86_patch (rgctx_null_jumps [i], code);
 491
 492         g_free (rgctx_null_jumps);
 493
 494         x86_mov_reg_membase (code, MONO_ARCH_VTABLE_REG, X86_ESP, 4, 4);
 495
 496         if (aot) {
 497                 code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_SPECIFIC_TRAMPOLINE_LAZY_FETCH_ADDR, GUINT_TO_POINTER (slot));
 498                 x86_jump_reg (code, X86_EAX);
 499         } else {
 500                 tramp = (guint8*)mono_arch_create_specific_trampoline (GUINT_TO_POINTER (slot), MONO_TRAMPOLINE_RGCTX_LAZY_FETCH, mono_get_root_domain (), NULL);
 501
 502                 /* jump to the actual trampoline */
 503                 x86_jump_code (code, tramp);
 504         }
 505
 506         mono_arch_flush_icache (buf, code - buf);
 507         MONO_PROFILER_RAISE (jit_code_buffer, (buf, code - buf, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL));
 508
 509         g_assert (code - buf <= tramp_size);
 510
 511         char *name = mono_get_rgctx_fetch_trampoline_name (slot);
 512         *info = mono_tramp_info_create (name, buf, code - buf, ji, unwind_ops);
 513         g_free (name);
 514
 515         return buf;
 516 }
 517
 518 /*
 519  * mono_arch_create_general_rgctx_lazy_fetch_trampoline:
 520  *
 521  *   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
 522  * the trampoline to call if the slot is not filled.
 523  */
 524 gpointer
 525 mono_arch_create_general_rgctx_lazy_fetch_trampoline (MonoTrampInfo **info, gboolean aot)
 526 {
 527         guint8 *code, *buf;
 528         int tramp_size;
 529         MonoJumpInfo *ji = NULL;
 530         GSList *unwind_ops = NULL;
 531
 532         g_assert (aot);
 533
 534         unwind_ops = mono_arch_get_cie_program ();
 535
 536         tramp_size = 64;
 537
 538         code = buf = mono_global_codeman_reserve (tramp_size);
 539
 540         // FIXME: Currently, we always go to the slow path.
 541
 542         /* Load trampoline addr */
 543         x86_mov_reg_membase (code, X86_EAX, MONO_ARCH_RGCTX_REG, 4, 4);
 544         /* Load mrgctx/vtable */
 545         x86_mov_reg_membase (code, MONO_ARCH_VTABLE_REG, X86_ESP, 4, 4);
 546
 547         x86_jump_reg (code, X86_EAX);
 548
 549         mono_arch_flush_icache (buf, code - buf);
 550         MONO_PROFILER_RAISE (jit_code_buffer, (buf, code - buf, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL));
 551
 552         g_assert (code - buf <= tramp_size);
 553
 554         *info = mono_tramp_info_create ("rgctx_fetch_trampoline_general", buf, code - buf, ji, unwind_ops);
 555
 556         return buf;
 557 }
 558
 559 void
 560 mono_arch_invalidate_method (MonoJitInfo *ji, void *func, gpointer func_arg)
 561 {
 562         /* FIXME: This is not thread safe */
 563         guint8 *code = (guint8*)ji->code_start;
 564
 565         x86_push_imm (code, func_arg);
 566         x86_call_code (code, (guint8*)func);
 567 }
 568
 569 guint8*
 570 mono_arch_get_call_target (guint8 *code)
 571 {
 572         if (code [-5] == 0xe8) {
 573                 gint32 disp = *(gint32*)(code - 4);
 574                 guint8 *target = code + disp;
 575
 576                 return target;
 577         } else {
 578                 return NULL;
 579         }
 580 }
 581
 582 guint32
 583 mono_arch_get_plt_info_offset (guint8 *plt_entry, host_mgreg_t *regs, guint8 *code)
 584 {
 585         return *(guint32*)(plt_entry + 6);
 586 }
 587
 588 /*
 589  * mono_arch_get_gsharedvt_arg_trampoline:
 590  *
 591  *   Return a trampoline which passes ARG to the gsharedvt in/out trampoline ADDR.
 592  */
 593 gpointer
 594 mono_arch_get_gsharedvt_arg_trampoline (MonoDomain *domain, gpointer arg, gpointer addr)
 595 {
 596         guint8 *code, *start;
 597         int buf_len;
 598         GSList *unwind_ops;
 599
 600         buf_len = 10;
 601
 602         start = code = mono_domain_code_reserve (domain, buf_len);
 603
 604         unwind_ops = mono_arch_get_cie_program ();
 605
 606         x86_mov_reg_imm (code, X86_EAX, arg);
 607         x86_jump_code (code, addr);
 608         g_assert ((code - start) <= buf_len);
 609
 610         mono_arch_flush_icache (start, code - start);
 611         MONO_PROFILER_RAISE (jit_code_buffer, (start, code - start, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL));
 612
 613         mono_tramp_info_register (mono_tramp_info_create (NULL, start, code - start, NULL, unwind_ops), domain);
 614
 615         return start;
 616 }
 617
 618 /*
 619  * mono_arch_create_sdb_trampoline:
 620  *
 621  *   Return a trampoline which captures the current context, passes it to
 622  * mini_get_dbg_callbacks ()->single_step_from_context ()/mini_get_dbg_callbacks ()->breakpoint_from_context (),
 623  * then restores the (potentially changed) context.
 624  */
 625 guint8*
 626 mono_arch_create_sdb_trampoline (gboolean single_step, MonoTrampInfo **info, gboolean aot)
 627 {
 628         int tramp_size = 256;
 629         int framesize, ctx_offset, cfa_offset;
 630         guint8 *code, *buf;
 631         GSList *unwind_ops = NULL;
 632         MonoJumpInfo *ji = NULL;
 633
 634         code = buf = mono_global_codeman_reserve (tramp_size);
 635
 636         framesize = 0;
 637
 638         /* Argument area */
 639         framesize += sizeof (target_mgreg_t);
 640
 641         framesize = ALIGN_TO (framesize, 8);
 642         ctx_offset = framesize;
 643         framesize += sizeof (MonoContext);
 644
 645         framesize = ALIGN_TO (framesize, MONO_ARCH_FRAME_ALIGNMENT);
 646
 647         // CFA = sp + 4
 648         cfa_offset = 4;
 649         mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, 4);
 650         // IP saved at CFA - 4
 651         mono_add_unwind_op_offset (unwind_ops, code, buf, X86_NREG, -cfa_offset);
 652
 653         x86_push_reg (code, X86_EBP);
 654         cfa_offset += sizeof (target_mgreg_t);
 655         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 656         mono_add_unwind_op_offset (unwind_ops, code, buf, X86_EBP, - cfa_offset);
 657
 658         x86_mov_reg_reg (code, X86_EBP, X86_ESP);
 659         mono_add_unwind_op_def_cfa_reg (unwind_ops, code, buf, X86_EBP);
 660         /* The + 8 makes the stack aligned */
 661         x86_alu_reg_imm (code, X86_SUB, X86_ESP, framesize + 8);
 662
 663         /* Initialize a MonoContext structure on the stack */
 664         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eax), X86_EAX, sizeof (target_mgreg_t));
 665         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebx), X86_EBX, sizeof (target_mgreg_t));
 666         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ecx), X86_ECX, sizeof (target_mgreg_t));
 667         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edx), X86_EDX, sizeof (target_mgreg_t));
 668         x86_mov_reg_membase (code, X86_EAX, X86_EBP, 0, sizeof (target_mgreg_t));
 669         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebp), X86_EAX, sizeof (target_mgreg_t));
 670         x86_mov_reg_reg (code, X86_EAX, X86_EBP);
 671         x86_alu_reg_imm (code, X86_ADD, X86_EAX, cfa_offset);
 672         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, esp), X86_ESP, sizeof (target_mgreg_t));
 673         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, esi), X86_ESI, sizeof (target_mgreg_t));
 674         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edi), X86_EDI, sizeof (target_mgreg_t));
 675         x86_mov_reg_membase (code, X86_EAX, X86_EBP, 4, sizeof (target_mgreg_t));
 676         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eip), X86_EAX, sizeof (target_mgreg_t));
 677
 678         /* Call the single step/breakpoint function in sdb */
 679         x86_lea_membase (code, X86_EAX, X86_ESP, ctx_offset);
 680         x86_mov_membase_reg (code, X86_ESP, 0, X86_EAX, sizeof (target_mgreg_t));
 681
 682         if (aot) {
 683                 x86_breakpoint (code);
 684         } else {
 685                 if (single_step)
 686                         x86_call_code (code, mini_get_dbg_callbacks ()->single_step_from_context);
 687                 else
 688                         x86_call_code (code, mini_get_dbg_callbacks ()->breakpoint_from_context);
 689         }
 690
 691         /* Restore registers from ctx */
 692         /* Overwrite the saved ebp */
 693         x86_mov_reg_membase (code, X86_EAX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebp), sizeof (target_mgreg_t));
 694         x86_mov_membase_reg (code, X86_EBP, 0, X86_EAX, sizeof (target_mgreg_t));
 695         /* Overwrite saved eip */
 696         x86_mov_reg_membase (code, X86_EAX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eip), sizeof (target_mgreg_t));
 697         x86_mov_membase_reg (code, X86_EBP, 4, X86_EAX, sizeof (target_mgreg_t));
 698         x86_mov_reg_membase (code, X86_EAX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eax), sizeof (target_mgreg_t));
 699         x86_mov_reg_membase (code, X86_EBX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebx), sizeof (target_mgreg_t));
 700         x86_mov_reg_membase (code, X86_ECX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ecx), sizeof (target_mgreg_t));
 701         x86_mov_reg_membase (code, X86_EDX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edx), sizeof (target_mgreg_t));
 702         x86_mov_reg_membase (code, X86_ESI, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, esi), sizeof (target_mgreg_t));
 703         x86_mov_reg_membase (code, X86_EDI, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edi), sizeof (target_mgreg_t));
 704
 705         x86_leave (code);
 706         cfa_offset -= sizeof (target_mgreg_t);
 707         mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, cfa_offset);
 708         x86_ret (code);
 709
 710         mono_arch_flush_icache (code, code - buf);
 711         MONO_PROFILER_RAISE (jit_code_buffer, (buf, code - buf, MONO_PROFILER_CODE_BUFFER_HELPER, NULL));
 712         g_assert (code - buf <= tramp_size);
 713
 714         const char *tramp_name = single_step ? "sdb_single_step_trampoline" : "sdb_breakpoint_trampoline";
 715         *info = mono_tramp_info_create (tramp_name, buf, code - buf, ji, unwind_ops);
 716
 717         return buf;
 718 }