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_code_buffer_new (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_code_buffer_new (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                 /* The trampoline argument is at the top of the stack, and it contains the address we need to branch to */
 418                 if (tramp_type == MONO_TRAMPOLINE_HANDLER_BLOCK_GUARD) {
 419                         x86_pop_reg (code, X86_EAX);
 420                         cfa_offset -= sizeof (mgreg_t);
 421                         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 422                         x86_alu_reg_imm (code, X86_ADD, X86_ESP, 0x8);
 423                         x86_jump_reg (code, X86_EAX);
 424                 } else {
 425                         x86_ret (code);
 426                 }
 427         }
 428
 429         g_assert ((code - buf) <= 256);
 430         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_HELPER, NULL);
 431
 432         tramp_name = mono_get_generic_trampoline_name (tramp_type);
 433         *info = mono_tramp_info_create (tramp_name, buf, code - buf, ji, unwind_ops);
 434         g_free (tramp_name);
 435
 436         return buf;
 437 }
 438
 439 #define TRAMPOLINE_SIZE 10
 440
 441 gpointer
 442 mono_arch_create_specific_trampoline (gpointer arg1, MonoTrampolineType tramp_type, MonoDomain *domain, guint32 *code_len)
 443 {
 444         guint8 *code, *buf, *tramp;
 445
 446         tramp = mono_get_trampoline_code (tramp_type);
 447
 448         code = buf = mono_domain_code_reserve_align (domain, TRAMPOLINE_SIZE, 4);
 449
 450         x86_push_imm (buf, arg1);
 451         x86_jump_code (buf, tramp);
 452         g_assert ((buf - code) <= TRAMPOLINE_SIZE);
 453
 454         mono_arch_flush_icache (code, buf - code);
 455         mono_profiler_code_buffer_new (code, buf - code, MONO_PROFILER_CODE_BUFFER_SPECIFIC_TRAMPOLINE, mono_get_generic_trampoline_simple_name (tramp_type));
 456
 457         if (code_len)
 458                 *code_len = buf - code;
 459
 460         return code;
 461 }
 462
 463 gpointer
 464 mono_arch_create_rgctx_lazy_fetch_trampoline (guint32 slot, MonoTrampInfo **info, gboolean aot)
 465 {
 466         guint8 *tramp;
 467         guint8 *code, *buf;
 468         guint8 **rgctx_null_jumps;
 469         int tramp_size;
 470         int depth, index;
 471         int i;
 472         gboolean mrgctx;
 473         MonoJumpInfo *ji = NULL;
 474         GSList *unwind_ops = NULL;
 475
 476         unwind_ops = mono_arch_get_cie_program ();
 477
 478         mrgctx = MONO_RGCTX_SLOT_IS_MRGCTX (slot);
 479         index = MONO_RGCTX_SLOT_INDEX (slot);
 480         if (mrgctx)
 481                 index += MONO_SIZEOF_METHOD_RUNTIME_GENERIC_CONTEXT / sizeof (gpointer);
 482         for (depth = 0; ; ++depth) {
 483                 int size = mono_class_rgctx_get_array_size (depth, mrgctx);
 484
 485                 if (index < size - 1)
 486                         break;
 487                 index -= size - 1;
 488         }
 489
 490         tramp_size = (aot ? 64 : 36) + 6 * depth;
 491
 492         code = buf = mono_global_codeman_reserve (tramp_size);
 493
 494         rgctx_null_jumps = g_malloc (sizeof (guint8*) * (depth + 2));
 495
 496         /* load vtable/mrgctx ptr */
 497         x86_mov_reg_membase (code, X86_EAX, X86_ESP, 4, 4);
 498         if (!mrgctx) {
 499                 /* load rgctx ptr from vtable */
 500                 x86_mov_reg_membase (code, X86_EAX, X86_EAX, MONO_STRUCT_OFFSET (MonoVTable, runtime_generic_context), 4);
 501                 /* is the rgctx ptr null? */
 502                 x86_test_reg_reg (code, X86_EAX, X86_EAX);
 503                 /* if yes, jump to actual trampoline */
 504                 rgctx_null_jumps [0] = code;
 505                 x86_branch8 (code, X86_CC_Z, -1, 1);
 506         }
 507
 508         for (i = 0; i < depth; ++i) {
 509                 /* load ptr to next array */
 510                 if (mrgctx && i == 0)
 511                         x86_mov_reg_membase (code, X86_EAX, X86_EAX, MONO_SIZEOF_METHOD_RUNTIME_GENERIC_CONTEXT, 4);
 512                 else
 513                         x86_mov_reg_membase (code, X86_EAX, X86_EAX, 0, 4);
 514                 /* is the ptr null? */
 515                 x86_test_reg_reg (code, X86_EAX, X86_EAX);
 516                 /* if yes, jump to actual trampoline */
 517                 rgctx_null_jumps [i + 1] = code;
 518                 x86_branch8 (code, X86_CC_Z, -1, 1);
 519         }
 520
 521         /* fetch slot */
 522         x86_mov_reg_membase (code, X86_EAX, X86_EAX, sizeof (gpointer) * (index + 1), 4);
 523         /* is the slot null? */
 524         x86_test_reg_reg (code, X86_EAX, X86_EAX);
 525         /* if yes, jump to actual trampoline */
 526         rgctx_null_jumps [depth + 1] = code;
 527         x86_branch8 (code, X86_CC_Z, -1, 1);
 528         /* otherwise return */
 529         x86_ret (code);
 530
 531         for (i = mrgctx ? 1 : 0; i <= depth + 1; ++i)
 532                 x86_patch (rgctx_null_jumps [i], code);
 533
 534         g_free (rgctx_null_jumps);
 535
 536         x86_mov_reg_membase (code, MONO_ARCH_VTABLE_REG, X86_ESP, 4, 4);
 537
 538         if (aot) {
 539                 code = mono_arch_emit_load_aotconst (buf, code, &ji, MONO_PATCH_INFO_JIT_ICALL_ADDR, g_strdup_printf ("specific_trampoline_lazy_fetch_%u", slot));
 540                 x86_jump_reg (code, X86_EAX);
 541         } else {
 542                 tramp = mono_arch_create_specific_trampoline (GUINT_TO_POINTER (slot), MONO_TRAMPOLINE_RGCTX_LAZY_FETCH, mono_get_root_domain (), NULL);
 543
 544                 /* jump to the actual trampoline */
 545                 x86_jump_code (code, tramp);
 546         }
 547
 548         mono_arch_flush_icache (buf, code - buf);
 549         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL);
 550
 551         g_assert (code - buf <= tramp_size);
 552
 553         char *name = mono_get_rgctx_fetch_trampoline_name (slot);
 554         *info = mono_tramp_info_create (name, buf, code - buf, ji, unwind_ops);
 555         g_free (name);
 556
 557         return buf;
 558 }
 559
 560 /*
 561  * mono_arch_create_general_rgctx_lazy_fetch_trampoline:
 562  *
 563  *   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
 564  * the trampoline to call if the slot is not filled.
 565  */
 566 gpointer
 567 mono_arch_create_general_rgctx_lazy_fetch_trampoline (MonoTrampInfo **info, gboolean aot)
 568 {
 569         guint8 *code, *buf;
 570         int tramp_size;
 571         MonoJumpInfo *ji = NULL;
 572         GSList *unwind_ops = NULL;
 573
 574         g_assert (aot);
 575
 576         unwind_ops = mono_arch_get_cie_program ();
 577
 578         tramp_size = 64;
 579
 580         code = buf = mono_global_codeman_reserve (tramp_size);
 581
 582         // FIXME: Currently, we always go to the slow path.
 583
 584         /* Load trampoline addr */
 585         x86_mov_reg_membase (code, X86_EAX, MONO_ARCH_RGCTX_REG, 4, 4);
 586         /* Load mrgctx/vtable */
 587         x86_mov_reg_membase (code, MONO_ARCH_VTABLE_REG, X86_ESP, 4, 4);
 588
 589         x86_jump_reg (code, X86_EAX);
 590
 591         mono_arch_flush_icache (buf, code - buf);
 592         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL);
 593
 594         g_assert (code - buf <= tramp_size);
 595
 596         *info = mono_tramp_info_create ("rgctx_fetch_trampoline_general", buf, code - buf, ji, unwind_ops);
 597
 598         return buf;
 599 }
 600
 601 void
 602 mono_arch_invalidate_method (MonoJitInfo *ji, void *func, gpointer func_arg)
 603 {
 604         /* FIXME: This is not thread safe */
 605         guint8 *code = ji->code_start;
 606
 607         x86_push_imm (code, func_arg);
 608         x86_call_code (code, (guint8*)func);
 609 }
 610
 611 static gpointer
 612 handler_block_trampoline_helper (void)
 613 {
 614         MonoJitTlsData *jit_tls = mono_tls_get_jit_tls ();
 615         return jit_tls->handler_block_return_address;
 616 }
 617
 618 gpointer
 619 mono_arch_create_handler_block_trampoline (MonoTrampInfo **info, gboolean aot)
 620 {
 621         guint8 *tramp = mono_get_trampoline_code (MONO_TRAMPOLINE_HANDLER_BLOCK_GUARD);
 622         guint8 *code, *buf;
 623         int tramp_size = 64;
 624         MonoJumpInfo *ji = NULL;
 625         int cfa_offset;
 626         GSList *unwind_ops = NULL;
 627
 628         g_assert (!aot);
 629
 630         code = buf = mono_global_codeman_reserve (tramp_size);
 631
 632         unwind_ops = mono_arch_get_cie_program ();
 633         cfa_offset = sizeof (mgreg_t);
 634         /*
 635         This trampoline restore the call chain of the handler block then jumps into the code that deals with it.
 636         */
 637
 638         /*
 639          * We are in a method frame after the call emitted by OP_CALL_HANDLER.
 640          */
 641
 642         /*Slow path uses a c helper*/
 643         x86_call_code (code, handler_block_trampoline_helper);
 644         /* Simulate a call */
 645         /*Fix stack alignment*/
 646         x86_alu_reg_imm (code, X86_SUB, X86_ESP, 0x4);
 647         cfa_offset += sizeof (mgreg_t);
 648         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 649
 650         /* This is the address the trampoline will return to */
 651         x86_push_reg (code, X86_EAX);
 652         cfa_offset += sizeof (mgreg_t);
 653         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 654
 655         /* Dummy trampoline argument, since we call the generic trampoline directly */
 656         x86_push_imm (code, 0);
 657         cfa_offset += sizeof (mgreg_t);
 658         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 659         x86_jump_code (code, tramp);
 660
 661         mono_arch_flush_icache (buf, code - buf);
 662         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_HELPER, NULL);
 663         g_assert (code - buf <= tramp_size);
 664
 665         *info = mono_tramp_info_create ("handler_block_trampoline", buf, code - buf, ji, unwind_ops);
 666
 667         return buf;
 668 }
 669
 670 guint8*
 671 mono_arch_get_call_target (guint8 *code)
 672 {
 673         if (code [-5] == 0xe8) {
 674                 gint32 disp = *(gint32*)(code - 4);
 675                 guint8 *target = code + disp;
 676
 677                 return target;
 678         } else {
 679                 return NULL;
 680         }
 681 }
 682
 683 guint32
 684 mono_arch_get_plt_info_offset (guint8 *plt_entry, mgreg_t *regs, guint8 *code)
 685 {
 686         return *(guint32*)(plt_entry + 6);
 687 }
 688
 689 /*
 690  * mono_arch_get_gsharedvt_arg_trampoline:
 691  *
 692  *   Return a trampoline which passes ARG to the gsharedvt in/out trampoline ADDR.
 693  */
 694 gpointer
 695 mono_arch_get_gsharedvt_arg_trampoline (MonoDomain *domain, gpointer arg, gpointer addr)
 696 {
 697         guint8 *code, *start;
 698         int buf_len;
 699         GSList *unwind_ops;
 700
 701
 702         buf_len = 10;
 703
 704         start = code = mono_domain_code_reserve (domain, buf_len);
 705
 706         unwind_ops = mono_arch_get_cie_program ();
 707
 708         x86_mov_reg_imm (code, X86_EAX, arg);
 709         x86_jump_code (code, addr);
 710         g_assert ((code - start) <= buf_len);
 711
 712         mono_arch_flush_icache (start, code - start);
 713         mono_profiler_code_buffer_new (start, code - start, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL);
 714
 715         mono_tramp_info_register (mono_tramp_info_create (NULL, start, code - start, NULL, unwind_ops), domain);
 716
 717         return start;
 718 }
 719
 720 /*
 721  * mono_arch_create_sdb_trampoline:
 722  *
 723  *   Return a trampoline which captures the current context, passes it to
 724  * debugger_agent_single_step_from_context ()/debugger_agent_breakpoint_from_context (),
 725  * then restores the (potentially changed) context.
 726  */
 727 guint8*
 728 mono_arch_create_sdb_trampoline (gboolean single_step, MonoTrampInfo **info, gboolean aot)
 729 {
 730         int tramp_size = 256;
 731         int framesize, ctx_offset, cfa_offset;
 732         guint8 *code, *buf;
 733         GSList *unwind_ops = NULL;
 734         MonoJumpInfo *ji = NULL;
 735
 736         code = buf = mono_global_codeman_reserve (tramp_size);
 737
 738         framesize = 0;
 739
 740         /* Argument area */
 741         framesize += sizeof (mgreg_t);
 742
 743         framesize = ALIGN_TO (framesize, 8);
 744         ctx_offset = framesize;
 745         framesize += sizeof (MonoContext);
 746
 747         framesize = ALIGN_TO (framesize, MONO_ARCH_FRAME_ALIGNMENT);
 748
 749         // CFA = sp + 4
 750         cfa_offset = 4;
 751         mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, 4);
 752         // IP saved at CFA - 4
 753         mono_add_unwind_op_offset (unwind_ops, code, buf, X86_NREG, -cfa_offset);
 754
 755         x86_push_reg (code, X86_EBP);
 756         cfa_offset += sizeof(mgreg_t);
 757         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 758         mono_add_unwind_op_offset (unwind_ops, code, buf, X86_EBP, - cfa_offset);
 759
 760         x86_mov_reg_reg (code, X86_EBP, X86_ESP, sizeof(mgreg_t));
 761         mono_add_unwind_op_def_cfa_reg (unwind_ops, code, buf, X86_EBP);
 762         /* The + 8 makes the stack aligned */
 763         x86_alu_reg_imm (code, X86_SUB, X86_ESP, framesize + 8);
 764
 765         /* Initialize a MonoContext structure on the stack */
 766         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eax), X86_EAX, sizeof (mgreg_t));
 767         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebx), X86_EBX, sizeof (mgreg_t));
 768         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ecx), X86_ECX, sizeof (mgreg_t));
 769         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edx), X86_EDX, sizeof (mgreg_t));
 770         x86_mov_reg_membase (code, X86_EAX, X86_EBP, 0, sizeof (mgreg_t));
 771         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebp), X86_EAX, sizeof (mgreg_t));
 772         x86_mov_reg_reg (code, X86_EAX, X86_EBP, sizeof (mgreg_t));
 773         x86_alu_reg_imm (code, X86_ADD, X86_EAX, cfa_offset);
 774         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, esp), X86_ESP, sizeof (mgreg_t));
 775         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, esi), X86_ESI, sizeof (mgreg_t));
 776         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edi), X86_EDI, sizeof (mgreg_t));
 777         x86_mov_reg_membase (code, X86_EAX, X86_EBP, 4, sizeof (mgreg_t));
 778         x86_mov_membase_reg (code, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eip), X86_EAX, sizeof (mgreg_t));
 779
 780         /* Call the single step/breakpoint function in sdb */
 781         x86_lea_membase (code, X86_EAX, X86_ESP, ctx_offset);
 782         x86_mov_membase_reg (code, X86_ESP, 0, X86_EAX, sizeof (mgreg_t));
 783
 784         if (aot) {
 785                 x86_breakpoint (code);
 786         } else {
 787                 if (single_step)
 788                         x86_call_code (code, debugger_agent_single_step_from_context);
 789                 else
 790                         x86_call_code (code, debugger_agent_breakpoint_from_context);
 791         }
 792
 793         /* Restore registers from ctx */
 794         /* Overwrite the saved ebp */
 795         x86_mov_reg_membase (code, X86_EAX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebp), sizeof (mgreg_t));
 796         x86_mov_membase_reg (code, X86_EBP, 0, X86_EAX, sizeof (mgreg_t));
 797         /* Overwrite saved eip */
 798         x86_mov_reg_membase (code, X86_EAX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eip), sizeof (mgreg_t));
 799         x86_mov_membase_reg (code, X86_EBP, 4, X86_EAX, sizeof (mgreg_t));
 800         x86_mov_reg_membase (code, X86_EAX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, eax), sizeof (mgreg_t));
 801         x86_mov_reg_membase (code, X86_EBX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ebx), sizeof (mgreg_t));
 802         x86_mov_reg_membase (code, X86_ECX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, ecx), sizeof (mgreg_t));
 803         x86_mov_reg_membase (code, X86_EDX, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edx), sizeof (mgreg_t));
 804         x86_mov_reg_membase (code, X86_ESI, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, esi), sizeof (mgreg_t));
 805         x86_mov_reg_membase (code, X86_EDI, X86_ESP, ctx_offset + G_STRUCT_OFFSET (MonoContext, edi), sizeof (mgreg_t));
 806
 807         x86_leave (code);
 808         cfa_offset -= sizeof (mgreg_t);
 809         mono_add_unwind_op_def_cfa (unwind_ops, code, buf, X86_ESP, cfa_offset);
 810         x86_ret (code);
 811
 812         mono_arch_flush_icache (code, code - buf);
 813         g_assert (code - buf <= tramp_size);
 814
 815         const char *tramp_name = single_step ? "sdb_single_step_trampoline" : "sdb_breakpoint_trampoline";
 816         *info = mono_tramp_info_create (tramp_name, buf, code - buf, ji, unwind_ops);
 817
 818         return buf;
 819 }
 820