mono/mini/tramp-arm.c

   1 /*
   2  * tramp-arm.c: JIT trampoline code for ARM
   3  *
   4  * Authors:
   5  *   Paolo Molaro (lupus@ximian.com)
   6  *
   7  * (C) 2001-2003 Ximian, Inc.
   8  * Copyright 2003-2011 Novell Inc
   9  * Copyright 2011 Xamarin Inc
  10  * Licensed under the MIT license. See LICENSE file in the project root for full license information.
  11  */
  12
  13 #include <config.h>
  14 #include <glib.h>
  15
  16 #include <mono/metadata/abi-details.h>
  17 #include <mono/metadata/appdomain.h>
  18 #include <mono/metadata/marshal.h>
  19 #include <mono/metadata/tabledefs.h>
  20 #include <mono/metadata/profiler-private.h>
  21 #include <mono/arch/arm/arm-codegen.h>
  22 #include <mono/arch/arm/arm-vfp-codegen.h>
  23
  24 #include "mini.h"
  25 #include "mini-arm.h"
  26 #include "debugger-agent.h"
  27 #include "jit-icalls.h"
  28
  29 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
  30
  31 void
  32 mono_arch_patch_callsite (guint8 *method_start, guint8 *code_ptr, guint8 *addr)
  33 {
  34         guint32 *code = (guint32*)code_ptr;
  35
  36         /* This is the 'bl' or the 'mov pc' instruction */
  37         --code;
  38
  39         /*
  40          * Note that methods are called also with the bl opcode.
  41          */
  42         if ((((*code) >> 25)  & 7) == 5) {
  43                 /*g_print ("direct patching\n");*/
  44                 arm_patch ((guint8*)code, addr);
  45                 mono_arch_flush_icache ((guint8*)code, 4);
  46                 return;
  47         }
  48
  49         if ((((*code) >> 20) & 0xFF) == 0x12) {
  50                 /*g_print ("patching bx\n");*/
  51                 arm_patch ((guint8*)code, addr);
  52                 mono_arch_flush_icache ((guint8*)(code - 2), 4);
  53                 return;
  54         }
  55
  56         g_assert_not_reached ();
  57 }
  58
  59 void
  60 mono_arch_patch_plt_entry (guint8 *code, gpointer *got, mgreg_t *regs, guint8 *addr)
  61 {
  62         guint8 *jump_entry;
  63
  64         /* Patch the jump table entry used by the plt entry */
  65         if (*(guint32*)code == 0xe59fc000) {
  66                 /* ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0); */
  67                 guint32 offset = ((guint32*)code)[2];
  68
  69                 jump_entry = code + offset + 12;
  70         } else if (*(guint16*)(code - 4) == 0xf8df) {
  71                 /*
  72                  * Thumb PLT entry, begins with ldr.w ip, [pc, #8], code points to entry + 4, see
  73                  * mono_arm_get_thumb_plt_entry ().
  74                  */
  75                 guint32 offset;
  76
  77                 code -= 4;
  78                 offset = *(guint32*)(code + 12);
  79                 jump_entry = code + offset + 8;
  80         } else {
  81                 g_assert_not_reached ();
  82         }
  83
  84         *(guint8**)jump_entry = addr;
  85 }
  86
  87 #ifndef DISABLE_JIT
  88
  89 #define arm_is_imm12(v) ((int)(v) > -4096 && (int)(v) < 4096)
  90
  91 /*
  92  * Return the instruction to jump from code to target, 0 if not
  93  * reachable with a single instruction
  94  */
  95 static guint32
  96 branch_for_target_reachable (guint8 *branch, guint8 *target)
  97 {
  98         gint diff = target - branch - 8;
  99         g_assert ((diff & 3) == 0);
 100         if (diff >= 0) {
 101                 if (diff <= 33554431)
 102                         return (ARMCOND_AL << ARMCOND_SHIFT) | (ARM_BR_TAG) | (diff >> 2);
 103         } else {
 104                 /* diff between 0 and -33554432 */
 105                 if (diff >= -33554432)
 106                         return (ARMCOND_AL << ARMCOND_SHIFT) | (ARM_BR_TAG) | ((diff >> 2) & ~0xff000000);
 107         }
 108         return 0;
 109 }
 110
 111 static inline guint8*
 112 emit_bx (guint8* code, int reg)
 113 {
 114         if (mono_arm_thumb_supported ())
 115                 ARM_BX (code, reg);
 116         else
 117                 ARM_MOV_REG_REG (code, ARMREG_PC, reg);
 118         return code;
 119 }
 120
 121 /* Stack size for trampoline function
 122  */
 123 #define STACK ALIGN_TO (sizeof (MonoLMF), MONO_ARCH_FRAME_ALIGNMENT)
 124
 125 /* Method-specific trampoline code fragment size */
 126 #define METHOD_TRAMPOLINE_SIZE 64
 127
 128 /* Jump-specific trampoline code fragment size */
 129 #define JUMP_TRAMPOLINE_SIZE   64
 130
 131 guchar*
 132 mono_arch_create_generic_trampoline (MonoTrampolineType tramp_type, MonoTrampInfo **info, gboolean aot)
 133 {
 134         char *tramp_name;
 135         guint8 *buf, *code = NULL;
 136         guint8 *load_get_lmf_addr  = NULL, *load_trampoline  = NULL;
 137         gpointer *constants;
 138         int i, cfa_offset, regsave_size, lr_offset;
 139         GSList *unwind_ops = NULL;
 140         MonoJumpInfo *ji = NULL;
 141         int buf_len;
 142
 143         /* Now we'll create in 'buf' the ARM trampoline code. This
 144          is the trampoline code common to all methods  */
 145
 146         buf_len = 272;
 147
 148         /* Add space for saving/restoring VFP regs. */
 149         if (mono_arm_is_hard_float ())
 150                 buf_len += 8 * 2;
 151
 152         code = buf = mono_global_codeman_reserve (buf_len);
 153
 154         /*
 155          * At this point lr points to the specific arg and sp points to the saved
 156          * regs on the stack (all but PC and SP). The original LR value has been
 157          * saved as sp + LR_OFFSET by the push in the specific trampoline
 158          */
 159
 160         /* The size of the area already allocated by the push in the specific trampoline */
 161         regsave_size = 14 * sizeof (mgreg_t);
 162         /* The offset where lr was saved inside the regsave area */
 163         lr_offset = 13 * sizeof (mgreg_t);
 164
 165         // CFA = SP + (num registers pushed) * 4
 166         cfa_offset = 14 * sizeof (mgreg_t);
 167         mono_add_unwind_op_def_cfa (unwind_ops, code, buf, ARMREG_SP, cfa_offset);
 168         // PC saved at sp+LR_OFFSET
 169         mono_add_unwind_op_offset (unwind_ops, code, buf, ARMREG_LR, -4);
 170         /* Callee saved regs */
 171         for (i = 0; i < 8; ++i)
 172                 mono_add_unwind_op_offset (unwind_ops, code, buf, ARMREG_R4 + i, -regsave_size + ((4 + i) * 4));
 173
 174         if (aot) {
 175                 /*
 176                  * For page trampolines the data is in r1, so just move it, otherwise use the got slot as below.
 177                  * The trampoline contains a pc-relative offset to the got slot
 178                  * preceeding the got slot where the value is stored. The offset can be
 179                  * found at [lr + 0].
 180                  */
 181                 /* See if emit_trampolines () in aot-compiler.c for the '2' */
 182                 if (aot == 2) {
 183                         ARM_MOV_REG_REG (code, ARMREG_V2, ARMREG_R1);
 184                 } else {
 185                         ARM_LDR_IMM (code, ARMREG_V2, ARMREG_LR, 0);
 186                         ARM_ADD_REG_IMM (code, ARMREG_V2, ARMREG_V2, 4, 0);
 187                         ARM_LDR_REG_REG (code, ARMREG_V2, ARMREG_V2, ARMREG_LR);
 188                 }
 189         } else {
 190                 ARM_LDR_IMM (code, ARMREG_V2, ARMREG_LR, 0);
 191         }
 192         ARM_LDR_IMM (code, ARMREG_V3, ARMREG_SP, lr_offset);
 193
 194         /* we build the MonoLMF structure on the stack - see mini-arm.h
 195          * The pointer to the struct is put in r1.
 196          * the iregs array is already allocated on the stack by push.
 197          */
 198         code = mono_arm_emit_load_imm (code, ARMREG_R2, STACK - regsave_size);
 199         ARM_SUB_REG_REG (code, ARMREG_SP, ARMREG_SP, ARMREG_R2);
 200         cfa_offset += STACK - regsave_size;
 201         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 202         /* V1 == lmf */
 203         code = mono_arm_emit_load_imm (code, ARMREG_R2, STACK - sizeof (MonoLMF));
 204         ARM_ADD_REG_REG (code, ARMREG_V1, ARMREG_SP, ARMREG_R2);
 205
 206         /* ok, now we can continue with the MonoLMF setup, mostly untouched
 207          * from emit_prolog in mini-arm.c
 208          * This is a synthetized call to mono_get_lmf_addr ()
 209          */
 210         if (aot) {
 211                 ji = mono_patch_info_list_prepend (ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_get_lmf_addr");
 212                 ARM_LDR_IMM (code, ARMREG_R0, ARMREG_PC, 0);
 213                 ARM_B (code, 0);
 214                 *(gpointer*)code = NULL;
 215                 code += 4;
 216                 ARM_LDR_REG_REG (code, ARMREG_R0, ARMREG_PC, ARMREG_R0);
 217         } else {
 218                 load_get_lmf_addr = code;
 219                 code += 4;
 220         }
 221         ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
 222         code = emit_bx (code, ARMREG_R0);
 223
 224         /*
 225          * The stack now looks like:
 226          *       <saved regs>
 227          * v1 -> <rest of LMF>
 228          * sp -> <alignment>
 229          */
 230
 231         /* r0 is the result from mono_get_lmf_addr () */
 232         ARM_STR_IMM (code, ARMREG_R0, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, lmf_addr));
 233         /* new_lmf->previous_lmf = *lmf_addr */
 234         ARM_LDR_IMM (code, ARMREG_R2, ARMREG_R0, MONO_STRUCT_OFFSET (MonoLMF, previous_lmf));
 235         ARM_STR_IMM (code, ARMREG_R2, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, previous_lmf));
 236         /* *(lmf_addr) = r1 */
 237         ARM_STR_IMM (code, ARMREG_V1, ARMREG_R0, MONO_STRUCT_OFFSET (MonoLMF, previous_lmf));
 238         /* save method info (it's in v2) */
 239         if ((tramp_type == MONO_TRAMPOLINE_JIT) || (tramp_type == MONO_TRAMPOLINE_JUMP))
 240                 ARM_STR_IMM (code, ARMREG_V2, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, method));
 241         else {
 242                 ARM_MOV_REG_IMM8 (code, ARMREG_R2, 0);
 243                 ARM_STR_IMM (code, ARMREG_R2, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, method));
 244         }
 245         /* save caller SP */
 246         code = mono_arm_emit_load_imm (code, ARMREG_R2, cfa_offset);
 247         ARM_ADD_REG_REG (code, ARMREG_R2, ARMREG_SP, ARMREG_R2);
 248         ARM_STR_IMM (code, ARMREG_R2, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, sp));
 249         /* save caller FP */
 250         ARM_LDR_IMM (code, ARMREG_R2, ARMREG_V1, (MONO_STRUCT_OFFSET (MonoLMF, iregs) + ARMREG_FP*4));
 251         ARM_STR_IMM (code, ARMREG_R2, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, fp));
 252         /* save the IP (caller ip) */
 253         if (tramp_type == MONO_TRAMPOLINE_JUMP) {
 254                 ARM_MOV_REG_IMM8 (code, ARMREG_R2, 0);
 255         } else {
 256                 ARM_LDR_IMM (code, ARMREG_R2, ARMREG_V1, (MONO_STRUCT_OFFSET (MonoLMF, iregs) + 13*4));
 257         }
 258         ARM_STR_IMM (code, ARMREG_R2, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, ip));
 259
 260         /* Save VFP registers. */
 261         if (mono_arm_is_hard_float ()) {
 262                 /*
 263                  * Strictly speaking, we don't have to save d0-d7 in the LMF, but
 264                  * it's easier than attempting to store them on the stack since
 265                  * this trampoline code is pretty messy.
 266                  */
 267                 ARM_ADD_REG_IMM8 (code, ARMREG_R0, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, fregs));
 268                 ARM_FSTMD (code, ARM_VFP_D0, 8, ARMREG_R0);
 269         }
 270
 271         /*
 272          * Now we're ready to call xxx_trampoline ().
 273          */
 274         /* Arg 1: the saved registers */
 275         ARM_ADD_REG_IMM (code, ARMREG_R0, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, iregs), 0);
 276
 277         /* Arg 2: code (next address to the instruction that called us) */
 278         if (tramp_type == MONO_TRAMPOLINE_JUMP) {
 279                 ARM_MOV_REG_IMM8 (code, ARMREG_R1, 0);
 280         } else {
 281                 ARM_MOV_REG_REG (code, ARMREG_R1, ARMREG_V3);
 282         }
 283
 284         /* Arg 3: the specific argument, stored in v2
 285          */
 286         ARM_MOV_REG_REG (code, ARMREG_R2, ARMREG_V2);
 287
 288         if (aot) {
 289                 char *icall_name = g_strdup_printf ("trampoline_func_%d", tramp_type);
 290                 ji = mono_patch_info_list_prepend (ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, icall_name);
 291                 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0);
 292                 ARM_B (code, 0);
 293                 *(gpointer*)code = NULL;
 294                 code += 4;
 295                 ARM_LDR_REG_REG (code, ARMREG_IP, ARMREG_PC, ARMREG_IP);
 296         } else {
 297                 load_trampoline = code;
 298                 code += 4;
 299         }
 300
 301         ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
 302         code = emit_bx (code, ARMREG_IP);
 303
 304         /* OK, code address is now on r0. Move it to the place on the stack
 305          * where IP was saved (it is now no more useful to us and it can be
 306          * clobbered). This way we can just restore all the regs in one inst
 307          * and branch to IP.
 308          */
 309         ARM_STR_IMM (code, ARMREG_R0, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, iregs) + (ARMREG_R12 * sizeof (mgreg_t)));
 310
 311         /* Check for thread interruption */
 312         /* This is not perf critical code so no need to check the interrupt flag */
 313         /*
 314          * Have to call the _force_ variant, since there could be a protected wrapper on the top of the stack.
 315          */
 316         if (aot) {
 317                 ji = mono_patch_info_list_prepend (ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, "mono_interruption_checkpoint_from_trampoline");
 318                 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0);
 319                 ARM_B (code, 0);
 320                 *(gpointer*)code = NULL;
 321                 code += 4;
 322                 ARM_LDR_REG_REG (code, ARMREG_IP, ARMREG_PC, ARMREG_IP);
 323         } else {
 324                 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0);
 325                 ARM_B (code, 0);
 326                 *(gpointer*)code = mono_interruption_checkpoint_from_trampoline;
 327                 code += 4;
 328         }
 329         ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
 330         code = emit_bx (code, ARMREG_IP);
 331
 332         /*
 333          * Now we restore the MonoLMF (see emit_epilogue in mini-arm.c)
 334          * and the rest of the registers, so the method called will see
 335          * the same state as before we executed.
 336          */
 337         /* ip = previous_lmf */
 338         ARM_LDR_IMM (code, ARMREG_IP, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, previous_lmf));
 339         /* lr = lmf_addr */
 340         ARM_LDR_IMM (code, ARMREG_LR, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, lmf_addr));
 341         /* *(lmf_addr) = previous_lmf */
 342         ARM_STR_IMM (code, ARMREG_IP, ARMREG_LR, MONO_STRUCT_OFFSET (MonoLMF, previous_lmf));
 343
 344         /* Restore VFP registers. */
 345         if (mono_arm_is_hard_float ()) {
 346                 ARM_ADD_REG_IMM8 (code, ARMREG_R0, ARMREG_V1, MONO_STRUCT_OFFSET (MonoLMF, fregs));
 347                 ARM_FLDMD (code, ARM_VFP_D0, 8, ARMREG_R0);
 348         }
 349
 350         /* Non-standard function epilogue. Instead of doing a proper
 351          * return, we just jump to the compiled code.
 352          */
 353         /* Restore the registers and jump to the code:
 354          * Note that IP has been conveniently set to the method addr.
 355          */
 356         ARM_ADD_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, STACK - regsave_size);
 357         cfa_offset -= STACK - regsave_size;
 358         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 359         ARM_POP_NWB (code, 0x5fff);
 360         mono_add_unwind_op_same_value (unwind_ops, code, buf, ARMREG_LR);
 361         if (tramp_type == MONO_TRAMPOLINE_RGCTX_LAZY_FETCH)
 362                 ARM_MOV_REG_REG (code, ARMREG_R0, ARMREG_IP);
 363         ARM_ADD_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, regsave_size);
 364         cfa_offset -= regsave_size;
 365         g_assert (cfa_offset == 0);
 366         mono_add_unwind_op_def_cfa_offset (unwind_ops, code, buf, cfa_offset);
 367         if (MONO_TRAMPOLINE_TYPE_MUST_RETURN (tramp_type))
 368                 code = emit_bx (code, ARMREG_LR);
 369         else
 370                 code = emit_bx (code, ARMREG_IP);
 371
 372         constants = (gpointer*)code;
 373         constants [0] = mono_get_lmf_addr;
 374         constants [1] = (gpointer)mono_get_trampoline_func (tramp_type);
 375
 376         if (!aot) {
 377                 /* backpatch by emitting the missing instructions skipped above */
 378                 ARM_LDR_IMM (load_get_lmf_addr, ARMREG_R0, ARMREG_PC, (code - load_get_lmf_addr - 8));
 379                 ARM_LDR_IMM (load_trampoline, ARMREG_IP, ARMREG_PC, (code + 4 - load_trampoline - 8));
 380         }
 381
 382         code += 8;
 383
 384         /* Flush instruction cache, since we've generated code */
 385         mono_arch_flush_icache (buf, code - buf);
 386         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_HELPER, NULL);
 387
 388         /* Sanity check */
 389         g_assert ((code - buf) <= buf_len);
 390
 391         g_assert (info);
 392         tramp_name = mono_get_generic_trampoline_name (tramp_type);
 393         *info = mono_tramp_info_create (tramp_name, buf, code - buf, ji, unwind_ops);
 394         g_free (tramp_name);
 395
 396         return buf;
 397 }
 398
 399 #define SPEC_TRAMP_SIZE 24
 400
 401 gpointer
 402 mono_arch_create_specific_trampoline (gpointer arg1, MonoTrampolineType tramp_type, MonoDomain *domain, guint32 *code_len)
 403 {
 404         guint8 *code, *buf, *tramp;
 405         gpointer *constants;
 406         guint32 short_branch = FALSE;
 407         guint32 size = SPEC_TRAMP_SIZE;
 408
 409         tramp = mono_get_trampoline_code (tramp_type);
 410
 411         if (domain) {
 412                 mono_domain_lock (domain);
 413                 code = buf = mono_domain_code_reserve_align (domain, size, 4);
 414                 if ((short_branch = branch_for_target_reachable (code + 4, tramp))) {
 415                         size = 12;
 416                         mono_domain_code_commit (domain, code, SPEC_TRAMP_SIZE, size);
 417                 }
 418                 mono_domain_unlock (domain);
 419         } else {
 420                 code = buf = mono_global_codeman_reserve (size);
 421                 short_branch = FALSE;
 422         }
 423
 424         /* we could reduce this to 12 bytes if tramp is within reach:
 425          * ARM_PUSH ()
 426          * ARM_BL ()
 427          * method-literal
 428          * The called code can access method using the lr register
 429          * A 20 byte sequence could be:
 430          * ARM_PUSH ()
 431          * ARM_MOV_REG_REG (lr, pc)
 432          * ARM_LDR_IMM (pc, pc, 0)
 433          * method-literal
 434          * tramp-literal
 435          */
 436         /* We save all the registers, except PC and SP */
 437         ARM_PUSH (code, 0x5fff);
 438         if (short_branch) {
 439                 constants = (gpointer*)code;
 440                 constants [0] = GUINT_TO_POINTER (short_branch | (1 << 24));
 441                 constants [1] = arg1;
 442                 code += 8;
 443         } else {
 444                 ARM_LDR_IMM (code, ARMREG_R1, ARMREG_PC, 8); /* temp reg */
 445                 ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_PC);
 446                 code = emit_bx (code, ARMREG_R1);
 447
 448                 constants = (gpointer*)code;
 449                 constants [0] = arg1;
 450                 constants [1] = tramp;
 451                 code += 8;
 452         }
 453
 454         /* Flush instruction cache, since we've generated code */
 455         mono_arch_flush_icache (buf, code - buf);
 456         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_SPECIFIC_TRAMPOLINE, mono_get_generic_trampoline_simple_name (tramp_type));
 457
 458         g_assert ((code - buf) <= size);
 459
 460         if (code_len)
 461                 *code_len = code - buf;
 462
 463         return buf;
 464 }
 465
 466 /*
 467  * mono_arch_get_unbox_trampoline:
 468  * @m: method pointer
 469  * @addr: pointer to native code for @m
 470  *
 471  * when value type methods are called through the vtable we need to unbox the
 472  * this argument. This method returns a pointer to a trampoline which does
 473  * unboxing before calling the method
 474  */
 475 gpointer
 476 mono_arch_get_unbox_trampoline (MonoMethod *m, gpointer addr)
 477 {
 478         guint8 *code, *start;
 479         MonoDomain *domain = mono_domain_get ();
 480         GSList *unwind_ops;
 481         guint32 size = 16;
 482
 483         start = code = mono_domain_code_reserve (domain, size);
 484
 485         unwind_ops = mono_arch_get_cie_program ();
 486
 487         ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 4);
 488         ARM_ADD_REG_IMM8 (code, ARMREG_R0, ARMREG_R0, sizeof (MonoObject));
 489         code = emit_bx (code, ARMREG_IP);
 490         *(guint32*)code = (guint32)addr;
 491         code += 4;
 492         mono_arch_flush_icache (start, code - start);
 493         mono_profiler_code_buffer_new (start, code - start, MONO_PROFILER_CODE_BUFFER_UNBOX_TRAMPOLINE, m);
 494         g_assert ((code - start) <= size);
 495         /*g_print ("unbox trampoline at %d for %s:%s\n", this_pos, m->klass->name, m->name);
 496         g_print ("unbox code is at %p for method at %p\n", start, addr);*/
 497
 498         mono_tramp_info_register (mono_tramp_info_create (NULL, start, code - start, NULL, unwind_ops), domain);
 499
 500         return start;
 501 }
 502
 503 gpointer
 504 mono_arch_get_static_rgctx_trampoline (MonoMethod *m, MonoMethodRuntimeGenericContext *mrgctx, gpointer addr)
 505 {
 506         guint8 *code, *start;
 507         GSList *unwind_ops;
 508         int buf_len = 16;
 509         MonoDomain *domain = mono_domain_get ();
 510
 511         start = code = mono_domain_code_reserve (domain, buf_len);
 512
 513         unwind_ops = mono_arch_get_cie_program ();
 514
 515         ARM_LDR_IMM (code, MONO_ARCH_RGCTX_REG, ARMREG_PC, 0);
 516         ARM_LDR_IMM (code, ARMREG_PC, ARMREG_PC, 0);
 517         *(guint32*)code = (guint32)mrgctx;
 518         code += 4;
 519         *(guint32*)code = (guint32)addr;
 520         code += 4;
 521
 522         g_assert ((code - start) <= buf_len);
 523
 524         mono_arch_flush_icache (start, code - start);
 525         mono_profiler_code_buffer_new (start, code - start, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL);
 526
 527         mono_tramp_info_register (mono_tramp_info_create (NULL, start, code - start, NULL, unwind_ops), domain);
 528
 529         return start;
 530 }
 531
 532 gpointer
 533 mono_arch_create_rgctx_lazy_fetch_trampoline (guint32 slot, MonoTrampInfo **info, gboolean aot)
 534 {
 535         guint8 *tramp;
 536         guint8 *code, *buf;
 537         int tramp_size;
 538         guint32 code_len;
 539         guint8 **rgctx_null_jumps;
 540         int depth, index;
 541         int i, njumps;
 542         gboolean mrgctx;
 543         MonoJumpInfo *ji = NULL;
 544         GSList *unwind_ops = NULL;
 545
 546         mrgctx = MONO_RGCTX_SLOT_IS_MRGCTX (slot);
 547         index = MONO_RGCTX_SLOT_INDEX (slot);
 548         if (mrgctx)
 549                 index += MONO_SIZEOF_METHOD_RUNTIME_GENERIC_CONTEXT / sizeof (gpointer);
 550         for (depth = 0; ; ++depth) {
 551                 int size = mono_class_rgctx_get_array_size (depth, mrgctx);
 552
 553                 if (index < size - 1)
 554                         break;
 555                 index -= size - 1;
 556         }
 557
 558         tramp_size = 64 + 16 * depth;
 559
 560         code = buf = mono_global_codeman_reserve (tramp_size);
 561
 562         unwind_ops = mono_arch_get_cie_program ();
 563
 564         rgctx_null_jumps = g_malloc (sizeof (guint8*) * (depth + 2));
 565         njumps = 0;
 566
 567         /* The vtable/mrgctx is in R0 */
 568         g_assert (MONO_ARCH_VTABLE_REG == ARMREG_R0);
 569
 570         if (mrgctx) {
 571                 /* get mrgctx ptr */
 572                 ARM_MOV_REG_REG (code, ARMREG_R1, ARMREG_R0);
 573         } else {
 574                 /* load rgctx ptr from vtable */
 575                 g_assert (arm_is_imm12 (MONO_STRUCT_OFFSET (MonoVTable, runtime_generic_context)));
 576                 ARM_LDR_IMM (code, ARMREG_R1, ARMREG_R0, MONO_STRUCT_OFFSET (MonoVTable, runtime_generic_context));
 577                 /* is the rgctx ptr null? */
 578                 ARM_CMP_REG_IMM (code, ARMREG_R1, 0, 0);
 579                 /* if yes, jump to actual trampoline */
 580                 rgctx_null_jumps [njumps ++] = code;
 581                 ARM_B_COND (code, ARMCOND_EQ, 0);
 582         }
 583
 584         for (i = 0; i < depth; ++i) {
 585                 /* load ptr to next array */
 586                 if (mrgctx && i == 0) {
 587                         g_assert (arm_is_imm12 (MONO_SIZEOF_METHOD_RUNTIME_GENERIC_CONTEXT));
 588                         ARM_LDR_IMM (code, ARMREG_R1, ARMREG_R1, MONO_SIZEOF_METHOD_RUNTIME_GENERIC_CONTEXT);
 589                 } else {
 590                         ARM_LDR_IMM (code, ARMREG_R1, ARMREG_R1, 0);
 591                 }
 592                 /* is the ptr null? */
 593                 ARM_CMP_REG_IMM (code, ARMREG_R1, 0, 0);
 594                 /* if yes, jump to actual trampoline */
 595                 rgctx_null_jumps [njumps ++] = code;
 596                 ARM_B_COND (code, ARMCOND_EQ, 0);
 597         }
 598
 599         /* fetch slot */
 600         code = mono_arm_emit_load_imm (code, ARMREG_R2, sizeof (gpointer) * (index + 1));
 601         ARM_LDR_REG_REG (code, ARMREG_R1, ARMREG_R1, ARMREG_R2);
 602         /* is the slot null? */
 603         ARM_CMP_REG_IMM (code, ARMREG_R1, 0, 0);
 604         /* if yes, jump to actual trampoline */
 605         rgctx_null_jumps [njumps ++] = code;
 606         ARM_B_COND (code, ARMCOND_EQ, 0);
 607         /* otherwise return, result is in R1 */
 608         ARM_MOV_REG_REG (code, ARMREG_R0, ARMREG_R1);
 609         code = emit_bx (code, ARMREG_LR);
 610
 611         g_assert (njumps <= depth + 2);
 612         for (i = 0; i < njumps; ++i)
 613                 arm_patch (rgctx_null_jumps [i], code);
 614
 615         g_free (rgctx_null_jumps);
 616
 617         /* Slowpath */
 618
 619         /* The vtable/mrgctx is still in R0 */
 620
 621         if (aot) {
 622                 ji = mono_patch_info_list_prepend (ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, g_strdup_printf ("specific_trampoline_lazy_fetch_%u", slot));
 623                 ARM_LDR_IMM (code, ARMREG_R1, ARMREG_PC, 0);
 624                 ARM_B (code, 0);
 625                 *(gpointer*)code = NULL;
 626                 code += 4;
 627                 ARM_LDR_REG_REG (code, ARMREG_PC, ARMREG_PC, ARMREG_R1);
 628         } else {
 629                 tramp = mono_arch_create_specific_trampoline (GUINT_TO_POINTER (slot), MONO_TRAMPOLINE_RGCTX_LAZY_FETCH, mono_get_root_domain (), &code_len);
 630
 631                 /* Jump to the actual trampoline */
 632                 ARM_LDR_IMM (code, ARMREG_R1, ARMREG_PC, 0); /* temp reg */
 633                 code = emit_bx (code, ARMREG_R1);
 634                 *(gpointer*)code = tramp;
 635                 code += 4;
 636         }
 637
 638         mono_arch_flush_icache (buf, code - buf);
 639         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL);
 640
 641         g_assert (code - buf <= tramp_size);
 642
 643         char *name = mono_get_rgctx_fetch_trampoline_name (slot);
 644         *info = mono_tramp_info_create (name, buf, code - buf, ji, unwind_ops);
 645         g_free (name);
 646
 647         return buf;
 648 }
 649
 650 gpointer
 651 mono_arch_create_general_rgctx_lazy_fetch_trampoline (MonoTrampInfo **info, gboolean aot)
 652 {
 653         guint8 *code, *buf;
 654         int tramp_size;
 655         MonoJumpInfo *ji = NULL;
 656         GSList *unwind_ops = NULL;
 657
 658         g_assert (aot);
 659
 660         tramp_size = 32;
 661
 662         code = buf = mono_global_codeman_reserve (tramp_size);
 663
 664         unwind_ops = mono_arch_get_cie_program ();
 665
 666         // FIXME: Currently, we always go to the slow path.
 667         /* Load trampoline addr */
 668         ARM_LDR_IMM (code, ARMREG_R1, MONO_ARCH_RGCTX_REG, 4);
 669         /* The vtable/mrgctx is in R0 */
 670         g_assert (MONO_ARCH_VTABLE_REG == ARMREG_R0);
 671         code = emit_bx (code, ARMREG_R1);
 672
 673         mono_arch_flush_icache (buf, code - buf);
 674         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL);
 675
 676         g_assert (code - buf <= tramp_size);
 677
 678         *info = mono_tramp_info_create ("rgctx_fetch_trampoline_general", buf, code - buf, ji, unwind_ops);
 679
 680         return buf;
 681 }
 682
 683 static gpointer
 684 handler_block_trampoline_helper (gpointer *ptr)
 685 {
 686         MonoJitTlsData *jit_tls = mono_tls_get_jit_tls ();
 687         return jit_tls->handler_block_return_address;
 688 }
 689
 690 gpointer
 691 mono_arch_create_handler_block_trampoline (MonoTrampInfo **info, gboolean aot)
 692 {
 693         guint8 *tramp;
 694         guint8 *code, *buf;
 695         int tramp_size = 64;
 696         MonoJumpInfo *ji = NULL;
 697         GSList *unwind_ops = NULL;
 698
 699         g_assert (!aot);
 700
 701         code = buf = mono_global_codeman_reserve (tramp_size);
 702
 703         unwind_ops = mono_arch_get_cie_program ();
 704
 705         tramp = mono_arch_create_specific_trampoline (NULL, MONO_TRAMPOLINE_HANDLER_BLOCK_GUARD, NULL, NULL);
 706
 707         /*
 708         This trampoline restore the call chain of the handler block then jumps into the code that deals with it.
 709         */
 710
 711         /*
 712          * We are in a method frame after the call emitted by OP_CALL_HANDLER.
 713          */
 714         /* Obtain jit_tls->handler_block_return_address */
 715         ARM_LDR_IMM (code, ARMREG_R0, ARMREG_PC, 0);
 716         ARM_B (code, 0);
 717         *(gpointer*)code = handler_block_trampoline_helper;
 718         code += 4;
 719
 720         /* Set it as the return address so the trampoline will return to it */
 721         ARM_MOV_REG_REG (code, ARMREG_LR, ARMREG_R0);
 722
 723         /* Call the trampoline */
 724         ARM_LDR_IMM (code, ARMREG_R0, ARMREG_PC, 0);
 725         code = emit_bx (code, ARMREG_R0);
 726         *(gpointer*)code = tramp;
 727         code += 4;
 728
 729         mono_arch_flush_icache (buf, code - buf);
 730         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_HELPER, NULL);
 731         g_assert (code - buf <= tramp_size);
 732
 733         *info = mono_tramp_info_create ("handler_block_trampoline", buf, code - buf, ji, unwind_ops);
 734
 735         return buf;
 736 }
 737
 738 guint8*
 739 mono_arch_create_sdb_trampoline (gboolean single_step, MonoTrampInfo **info, gboolean aot)
 740 {
 741         guint8 *buf, *code;
 742         GSList *unwind_ops = NULL;
 743         MonoJumpInfo *ji = NULL;
 744         int frame_size;
 745
 746         buf = code = mono_global_codeman_reserve (96);
 747
 748         /*
 749          * Construct the MonoContext structure on the stack.
 750          */
 751
 752         frame_size = sizeof (MonoContext);
 753         frame_size = ALIGN_TO (frame_size, MONO_ARCH_FRAME_ALIGNMENT);
 754         ARM_SUB_REG_IMM8 (code, ARMREG_SP, ARMREG_SP, frame_size);
 755
 756         /* save ip, lr and pc into their correspodings ctx.regs slots. */
 757         ARM_STR_IMM (code, ARMREG_IP, ARMREG_SP, MONO_STRUCT_OFFSET (MonoContext, regs) + sizeof (mgreg_t) * ARMREG_IP);
 758         ARM_STR_IMM (code, ARMREG_LR, ARMREG_SP, MONO_STRUCT_OFFSET (MonoContext, regs) + 4 * ARMREG_LR);
 759         ARM_STR_IMM (code, ARMREG_LR, ARMREG_SP, MONO_STRUCT_OFFSET (MonoContext, regs) + 4 * ARMREG_PC);
 760
 761         /* save r0..r10 and fp */
 762         ARM_ADD_REG_IMM8 (code, ARMREG_IP, ARMREG_SP, MONO_STRUCT_OFFSET (MonoContext, regs));
 763         ARM_STM (code, ARMREG_IP, 0x0fff);
 764
 765         /* now we can update fp. */
 766         ARM_MOV_REG_REG (code, ARMREG_FP, ARMREG_SP);
 767
 768         /* make ctx.esp hold the actual value of sp at the beginning of this method. */
 769         ARM_ADD_REG_IMM8 (code, ARMREG_R0, ARMREG_FP, frame_size);
 770         ARM_STR_IMM (code, ARMREG_R0, ARMREG_IP, 4 * ARMREG_SP);
 771         ARM_STR_IMM (code, ARMREG_R0, ARMREG_FP, MONO_STRUCT_OFFSET (MonoContext, regs) + 4 * ARMREG_SP);
 772
 773         /* make ctx.eip hold the address of the call. */
 774         //ARM_SUB_REG_IMM8 (code, ARMREG_LR, ARMREG_LR, 4);
 775         ARM_STR_IMM (code, ARMREG_LR, ARMREG_FP, MONO_STRUCT_OFFSET (MonoContext, pc));
 776
 777         /* r0 now points to the MonoContext */
 778         ARM_MOV_REG_REG (code, ARMREG_R0, ARMREG_FP);
 779
 780         /* call */
 781         if (aot) {
 782                 if (single_step)
 783                         ji = mono_patch_info_list_prepend (ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, "debugger_agent_single_step_from_context");
 784                 else
 785                         ji = mono_patch_info_list_prepend (ji, code - buf, MONO_PATCH_INFO_JIT_ICALL_ADDR, "debugger_agent_breakpoint_from_context");
 786                 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0);
 787                 ARM_B (code, 0);
 788                 *(gpointer*)code = NULL;
 789                 code += 4;
 790                 ARM_LDR_REG_REG (code, ARMREG_IP, ARMREG_PC, ARMREG_IP);
 791                 ARM_BLX_REG (code, ARMREG_IP);
 792         } else {
 793                 ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 0);
 794                 ARM_B (code, 0);
 795                 if (single_step)
 796                         *(gpointer*)code = debugger_agent_single_step_from_context;
 797                 else
 798                         *(gpointer*)code = debugger_agent_breakpoint_from_context;
 799                 code += 4;
 800                 ARM_BLX_REG (code, ARMREG_IP);
 801         }
 802
 803         /* we're back; save ctx.eip and ctx.esp into the corresponding regs slots. */
 804         ARM_LDR_IMM (code, ARMREG_R0, ARMREG_FP, MONO_STRUCT_OFFSET (MonoContext, pc));
 805         ARM_STR_IMM (code, ARMREG_R0, ARMREG_FP, MONO_STRUCT_OFFSET (MonoContext, regs) + 4 * ARMREG_LR);
 806         ARM_STR_IMM (code, ARMREG_R0, ARMREG_FP, MONO_STRUCT_OFFSET (MonoContext, regs) + 4 * ARMREG_PC);
 807
 808         /* make ip point to the regs array, then restore everything, including pc. */
 809         ARM_ADD_REG_IMM8 (code, ARMREG_IP, ARMREG_FP, MONO_STRUCT_OFFSET (MonoContext, regs));
 810         ARM_LDM (code, ARMREG_IP, 0xffff);
 811
 812         mono_arch_flush_icache (buf, code - buf);
 813         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_HELPER, NULL);
 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
 821 #else
 822
 823 guchar*
 824 mono_arch_create_generic_trampoline (MonoTrampolineType tramp_type, MonoTrampInfo **info, gboolean aot)
 825 {
 826         g_assert_not_reached ();
 827         return NULL;
 828 }
 829
 830 gpointer
 831 mono_arch_create_specific_trampoline (gpointer arg1, MonoTrampolineType tramp_type, MonoDomain *domain, guint32 *code_len)
 832 {
 833         g_assert_not_reached ();
 834         return NULL;
 835 }
 836
 837 gpointer
 838 mono_arch_get_unbox_trampoline (MonoMethod *m, gpointer addr)
 839 {
 840         g_assert_not_reached ();
 841         return NULL;
 842 }
 843
 844 gpointer
 845 mono_arch_get_static_rgctx_trampoline (MonoMethod *m, MonoMethodRuntimeGenericContext *mrgctx, gpointer addr)
 846 {
 847         g_assert_not_reached ();
 848         return NULL;
 849 }
 850
 851 gpointer
 852 mono_arch_create_rgctx_lazy_fetch_trampoline (guint32 slot, MonoTrampInfo **info, gboolean aot)
 853 {
 854         g_assert_not_reached ();
 855         return NULL;
 856 }
 857
 858 gpointer
 859 mono_arch_create_handler_block_trampoline (MonoTrampInfo **info, gboolean aot)
 860 {
 861         g_assert_not_reached ();
 862         return NULL;
 863 }
 864
 865 guint8*
 866 mono_arch_create_sdb_trampoline (gboolean single_step, MonoTrampInfo **info, gboolean aot)
 867 {
 868         g_assert_not_reached ();
 869         return NULL;
 870 }
 871
 872 #endif /* DISABLE_JIT */
 873
 874 guint8*
 875 mono_arch_get_call_target (guint8 *code)
 876 {
 877         guint32 ins = ((guint32*)(gpointer)code) [-1];
 878
 879         /* Should be a 'bl' or a 'b' */
 880         if (((ins >> 25) & 0x7) == 0x5) {
 881                 gint32 disp = ((((gint32)ins) & 0xffffff) << 8) >> 8;
 882                 guint8 *target = code - 4 + 8 + (disp * 4);
 883
 884                 return target;
 885         } else {
 886                 return NULL;
 887         }
 888 }
 889
 890 guint32
 891 mono_arch_get_plt_info_offset (guint8 *plt_entry, mgreg_t *regs, guint8 *code)
 892 {
 893         /* The offset is stored as the 4th word of the plt entry */
 894         return ((guint32*)plt_entry) [3];
 895 }
 896
 897 /*
 898  * Return the address of the PLT entry called by the thumb code CODE.
 899  */
 900 guint8*
 901 mono_arm_get_thumb_plt_entry (guint8 *code)
 902 {
 903         int s, j1, j2, imm10, imm11, i1, i2, imm32;
 904         guint8 *bl, *base;
 905         guint16 t1, t2;
 906         guint8 *target;
 907
 908         /* code should be right after a BL */
 909         code = (guint8*)((mgreg_t)code & ~1);
 910         base = (guint8*)((mgreg_t)code & ~3);
 911         bl = code - 4;
 912         t1 = ((guint16*)bl) [0];
 913         t2 = ((guint16*)bl) [1];
 914
 915         g_assert ((t1 >> 11) == 0x1e);
 916
 917         s = (t1 >> 10) & 0x1;
 918         imm10 = (t1 >> 0) & 0x3ff;
 919         j1 = (t2 >> 13) & 0x1;
 920         j2 = (t2 >> 11) & 0x1;
 921         imm11 = t2 & 0x7ff;
 922
 923         i1 = (s ^ j1) ? 0 : 1;
 924         i2 = (s ^ j2) ? 0 : 1;
 925
 926         imm32 = (imm11 << 1) | (imm10 << 12) | (i2 << 22) | (i1 << 23);
 927         if (s)
 928                 /* Sign extend from 24 bits to 32 bits */
 929                 imm32 = ((gint32)imm32 << 8) >> 8;
 930
 931         target = code + imm32;
 932
 933         /* target now points to the thumb plt entry */
 934         /* ldr.w r12, [pc, #8] */
 935         g_assert (((guint16*)target) [0] == 0xf8df);
 936         g_assert (((guint16*)target) [1] == 0xc008);
 937
 938         /*
 939          * The PLT info offset is at offset 16, but mono_arch_get_plt_entry_offset () returns
 940          * the 3rd word, so compensate by returning a different value.
 941          */
 942         target += 4;
 943
 944         return target;
 945 }
 946
 947 #ifndef DISABLE_JIT
 948
 949 /*
 950  * mono_arch_get_gsharedvt_arg_trampoline:
 951  *
 952  *   See tramp-x86.c for documentation.
 953  */
 954 gpointer
 955 mono_arch_get_gsharedvt_arg_trampoline (MonoDomain *domain, gpointer arg, gpointer addr)
 956 {
 957         guint8 *code, *buf;
 958         int buf_len;
 959         gpointer *constants;
 960
 961         buf_len = 24;
 962
 963         buf = code = mono_domain_code_reserve (domain, buf_len);
 964
 965         /* Similar to the specialized trampoline code */
 966         ARM_PUSH (code, (1 << ARMREG_R0) | (1 << ARMREG_R1) | (1 << ARMREG_R2) | (1 << ARMREG_R3) | (1 << ARMREG_LR));
 967         ARM_LDR_IMM (code, ARMREG_IP, ARMREG_PC, 8);
 968         /* arg is passed in LR */
 969         ARM_LDR_IMM (code, ARMREG_LR, ARMREG_PC, 0);
 970         code = emit_bx (code, ARMREG_IP);
 971         constants = (gpointer*)code;
 972         constants [0] = arg;
 973         constants [1] = addr;
 974         code += 8;
 975
 976         g_assert ((code - buf) <= buf_len);
 977
 978         mono_arch_flush_icache (buf, code - buf);
 979         mono_profiler_code_buffer_new (buf, code - buf, MONO_PROFILER_CODE_BUFFER_GENERICS_TRAMPOLINE, NULL);
 980
 981         mono_tramp_info_register (mono_tramp_info_create (NULL, buf, code - buf, NULL, NULL), domain);
 982
 983         return buf;
 984 }
 985
 986 #else
 987
 988 gpointer
 989 mono_arch_get_gsharedvt_arg_trampoline (MonoDomain *domain, gpointer arg, gpointer addr)
 990 {
 991         g_assert_not_reached ();
 992         return NULL;
 993 }
 994
 995 #endif