gdb/msp430-tdep.c

   1 /* Target-dependent code for the Texas Instruments MSP430 for GDB, the
   2    GNU debugger.
   3
   4    Copyright (C) 2012-2021 Free Software Foundation, Inc.
   5
   6    Contributed by Red Hat, Inc.
   7
   8    This file is part of GDB.
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  22
  23 #include "defs.h"
  24 #include "arch-utils.h"
  25 #include "prologue-value.h"
  26 #include "target.h"
  27 #include "regcache.h"
  28 #include "dis-asm.h"
  29 #include "gdbtypes.h"
  30 #include "frame.h"
  31 #include "frame-unwind.h"
  32 #include "frame-base.h"
  33 #include "value.h"
  34 #include "gdbcore.h"
  35 #include "dwarf2/frame.h"
  36 #include "reggroups.h"
  37
  38 #include "elf/msp430.h"
  39 #include "opcode/msp430-decode.h"
  40 #include "elf-bfd.h"
  41
  42 /* Register Numbers.  */
  43
  44 enum
  45 {
  46   MSP430_PC_RAW_REGNUM,
  47   MSP430_SP_RAW_REGNUM,
  48   MSP430_SR_RAW_REGNUM,
  49   MSP430_CG_RAW_REGNUM,
  50   MSP430_R4_RAW_REGNUM,
  51   MSP430_R5_RAW_REGNUM,
  52   MSP430_R6_RAW_REGNUM,
  53   MSP430_R7_RAW_REGNUM,
  54   MSP430_R8_RAW_REGNUM,
  55   MSP430_R9_RAW_REGNUM,
  56   MSP430_R10_RAW_REGNUM,
  57   MSP430_R11_RAW_REGNUM,
  58   MSP430_R12_RAW_REGNUM,
  59   MSP430_R13_RAW_REGNUM,
  60   MSP430_R14_RAW_REGNUM,
  61   MSP430_R15_RAW_REGNUM,
  62
  63   MSP430_NUM_REGS,
  64
  65   MSP430_PC_REGNUM = MSP430_NUM_REGS,
  66   MSP430_SP_REGNUM,
  67   MSP430_SR_REGNUM,
  68   MSP430_CG_REGNUM,
  69   MSP430_R4_REGNUM,
  70   MSP430_R5_REGNUM,
  71   MSP430_R6_REGNUM,
  72   MSP430_R7_REGNUM,
  73   MSP430_R8_REGNUM,
  74   MSP430_R9_REGNUM,
  75   MSP430_R10_REGNUM,
  76   MSP430_R11_REGNUM,
  77   MSP430_R12_REGNUM,
  78   MSP430_R13_REGNUM,
  79   MSP430_R14_REGNUM,
  80   MSP430_R15_REGNUM,
  81
  82   MSP430_NUM_TOTAL_REGS,
  83   MSP430_NUM_PSEUDO_REGS = MSP430_NUM_TOTAL_REGS - MSP430_NUM_REGS
  84 };
  85
  86 enum
  87 {
  88   /* TI MSP430 Architecture.  */
  89   MSP_ISA_MSP430,
  90
  91   /* TI MSP430X Architecture.  */
  92   MSP_ISA_MSP430X
  93 };
  94
  95 enum
  96 {
  97   /* The small code model limits code addresses to 16 bits.  */
  98   MSP_SMALL_CODE_MODEL,
  99
 100   /* The large code model uses 20 bit addresses for function
 101      pointers.  These are stored in memory using four bytes (32 bits).  */
 102   MSP_LARGE_CODE_MODEL
 103 };
 104
 105 /* Architecture specific data.  */
 106
 107 struct gdbarch_tdep
 108 {
 109   /* The ELF header flags specify the multilib used.  */
 110   int elf_flags;
 111
 112   /* One of MSP_ISA_MSP430 or MSP_ISA_MSP430X.  */
 113   int isa;
 114
 115   /* One of MSP_SMALL_CODE_MODEL or MSP_LARGE_CODE_MODEL.  If, at
 116      some point, we support different data models too, we'll probably
 117      structure things so that we can combine values using logical
 118      "or".  */
 119   int code_model;
 120 };
 121
 122 /* This structure holds the results of a prologue analysis.  */
 123
 124 struct msp430_prologue
 125 {
 126   /* The offset from the frame base to the stack pointer --- always
 127      zero or negative.
 128
 129      Calling this a "size" is a bit misleading, but given that the
 130      stack grows downwards, using offsets for everything keeps one
 131      from going completely sign-crazy: you never change anything's
 132      sign for an ADD instruction; always change the second operand's
 133      sign for a SUB instruction; and everything takes care of
 134      itself.  */
 135   int frame_size;
 136
 137   /* Non-zero if this function has initialized the frame pointer from
 138      the stack pointer, zero otherwise.  */
 139   int has_frame_ptr;
 140
 141   /* If has_frame_ptr is non-zero, this is the offset from the frame
 142      base to where the frame pointer points.  This is always zero or
 143      negative.  */
 144   int frame_ptr_offset;
 145
 146   /* The address of the first instruction at which the frame has been
 147      set up and the arguments are where the debug info says they are
 148      --- as best as we can tell.  */
 149   CORE_ADDR prologue_end;
 150
 151   /* reg_offset[R] is the offset from the CFA at which register R is
 152      saved, or 1 if register R has not been saved.  (Real values are
 153      always zero or negative.)  */
 154   int reg_offset[MSP430_NUM_TOTAL_REGS];
 155 };
 156
 157 /* Implement the "register_type" gdbarch method.  */
 158
 159 static struct type *
 160 msp430_register_type (struct gdbarch *gdbarch, int reg_nr)
 161 {
 162   if (reg_nr < MSP430_NUM_REGS)
 163     return builtin_type (gdbarch)->builtin_uint32;
 164   else if (reg_nr == MSP430_PC_REGNUM)
 165     return builtin_type (gdbarch)->builtin_func_ptr;
 166   else
 167     return builtin_type (gdbarch)->builtin_uint16;
 168 }
 169
 170 /* Implement another version of the "register_type" gdbarch method
 171    for msp430x.  */
 172
 173 static struct type *
 174 msp430x_register_type (struct gdbarch *gdbarch, int reg_nr)
 175 {
 176   if (reg_nr < MSP430_NUM_REGS)
 177     return builtin_type (gdbarch)->builtin_uint32;
 178   else if (reg_nr == MSP430_PC_REGNUM)
 179     return builtin_type (gdbarch)->builtin_func_ptr;
 180   else
 181     return builtin_type (gdbarch)->builtin_uint32;
 182 }
 183
 184 /* Implement the "register_name" gdbarch method.  */
 185
 186 static const char *
 187 msp430_register_name (struct gdbarch *gdbarch, int regnr)
 188 {
 189   static const char *const reg_names[] = {
 190     /* Raw registers.  */
 191     "", "", "", "", "", "", "", "",
 192     "", "", "", "", "", "", "", "",
 193     /* Pseudo registers.  */
 194     "pc", "sp", "sr", "cg", "r4", "r5", "r6", "r7",
 195     "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15"
 196   };
 197
 198   return reg_names[regnr];
 199 }
 200
 201 /* Implement the "register_reggroup_p" gdbarch method.  */
 202
 203 static int
 204 msp430_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
 205                             struct reggroup *group)
 206 {
 207   if (group == all_reggroup)
 208     return 1;
 209
 210   /* All other registers are saved and restored.  */
 211   if (group == save_reggroup || group == restore_reggroup)
 212     return (MSP430_NUM_REGS <= regnum && regnum < MSP430_NUM_TOTAL_REGS);
 213
 214   return group == general_reggroup;
 215 }
 216
 217 /* Implement the "pseudo_register_read" gdbarch method.  */
 218
 219 static enum register_status
 220 msp430_pseudo_register_read (struct gdbarch *gdbarch,
 221                              readable_regcache *regcache,
 222                              int regnum, gdb_byte *buffer)
 223 {
 224   if (MSP430_NUM_REGS <= regnum && regnum < MSP430_NUM_TOTAL_REGS)
 225     {
 226       enum register_status status;
 227       ULONGEST val;
 228       enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 229       int regsize = register_size (gdbarch, regnum);
 230       int raw_regnum = regnum - MSP430_NUM_REGS;
 231
 232       status = regcache->raw_read (raw_regnum, &val);
 233       if (status == REG_VALID)
 234         store_unsigned_integer (buffer, regsize, byte_order, val);
 235
 236       return status;
 237     }
 238   else
 239     gdb_assert_not_reached ("invalid pseudo register number");
 240 }
 241
 242 /* Implement the "pseudo_register_write" gdbarch method.  */
 243
 244 static void
 245 msp430_pseudo_register_write (struct gdbarch *gdbarch,
 246                               struct regcache *regcache,
 247                               int regnum, const gdb_byte *buffer)
 248 {
 249   if (MSP430_NUM_REGS <= regnum && regnum < MSP430_NUM_TOTAL_REGS)
 250
 251     {
 252       ULONGEST val;
 253       enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 254       int regsize = register_size (gdbarch, regnum);
 255       int raw_regnum = regnum - MSP430_NUM_REGS;
 256
 257       val = extract_unsigned_integer (buffer, regsize, byte_order);
 258       regcache_raw_write_unsigned (regcache, raw_regnum, val);
 259
 260     }
 261   else
 262     gdb_assert_not_reached ("invalid pseudo register number");
 263 }
 264
 265 /* Implement the `register_sim_regno' gdbarch method.  */
 266
 267 static int
 268 msp430_register_sim_regno (struct gdbarch *gdbarch, int regnum)
 269 {
 270   gdb_assert (regnum < MSP430_NUM_REGS);
 271
 272   /* So long as regnum is in [0, RL78_NUM_REGS), it's valid.  We
 273      just want to override the default here which disallows register
 274      numbers which have no names.  */
 275   return regnum;
 276 }
 277
 278 constexpr gdb_byte msp430_break_insn[] = { 0x43, 0x43 };
 279
 280 typedef BP_MANIPULATION (msp430_break_insn) msp430_breakpoint;
 281
 282 /* Define a "handle" struct for fetching the next opcode.  */
 283
 284 struct msp430_get_opcode_byte_handle
 285 {
 286   CORE_ADDR pc;
 287 };
 288
 289 /* Fetch a byte on behalf of the opcode decoder.  HANDLE contains
 290    the memory address of the next byte to fetch.  If successful,
 291    the address in the handle is updated and the byte fetched is
 292    returned as the value of the function.  If not successful, -1
 293    is returned.  */
 294
 295 static int
 296 msp430_get_opcode_byte (void *handle)
 297 {
 298   struct msp430_get_opcode_byte_handle *opcdata
 299     = (struct msp430_get_opcode_byte_handle *) handle;
 300   int status;
 301   gdb_byte byte;
 302
 303   status = target_read_memory (opcdata->pc, &byte, 1);
 304   if (status == 0)
 305     {
 306       opcdata->pc += 1;
 307       return byte;
 308     }
 309   else
 310     return -1;
 311 }
 312
 313 /* Function for finding saved registers in a 'struct pv_area'; this
 314    function is passed to pv_area::scan.
 315
 316    If VALUE is a saved register, ADDR says it was saved at a constant
 317    offset from the frame base, and SIZE indicates that the whole
 318    register was saved, record its offset.  */
 319
 320 static void
 321 check_for_saved (void *result_untyped, pv_t addr, CORE_ADDR size, pv_t value)
 322 {
 323   struct msp430_prologue *result = (struct msp430_prologue *) result_untyped;
 324
 325   if (value.kind == pvk_register
 326       && value.k == 0
 327       && pv_is_register (addr, MSP430_SP_REGNUM)
 328       && size == register_size (target_gdbarch (), value.reg))
 329     result->reg_offset[value.reg] = addr.k;
 330 }
 331
 332 /* Analyze a prologue starting at START_PC, going no further than
 333    LIMIT_PC.  Fill in RESULT as appropriate.  */
 334
 335 static void
 336 msp430_analyze_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc,
 337                          CORE_ADDR limit_pc, struct msp430_prologue *result)
 338 {
 339   CORE_ADDR pc, next_pc;
 340   int rn;
 341   pv_t reg[MSP430_NUM_TOTAL_REGS];
 342   CORE_ADDR after_last_frame_setup_insn = start_pc;
 343   int code_model = gdbarch_tdep (gdbarch)->code_model;
 344   int sz;
 345
 346   memset (result, 0, sizeof (*result));
 347
 348   for (rn = 0; rn < MSP430_NUM_TOTAL_REGS; rn++)
 349     {
 350       reg[rn] = pv_register (rn, 0);
 351       result->reg_offset[rn] = 1;
 352     }
 353
 354   pv_area stack (MSP430_SP_REGNUM, gdbarch_addr_bit (gdbarch));
 355
 356   /* The call instruction has saved the return address on the stack.  */
 357   sz = code_model == MSP_LARGE_CODE_MODEL ? 4 : 2;
 358   reg[MSP430_SP_REGNUM] = pv_add_constant (reg[MSP430_SP_REGNUM], -sz);
 359   stack.store (reg[MSP430_SP_REGNUM], sz, reg[MSP430_PC_REGNUM]);
 360
 361   pc = start_pc;
 362   while (pc < limit_pc)
 363     {
 364       int bytes_read;
 365       struct msp430_get_opcode_byte_handle opcode_handle;
 366       MSP430_Opcode_Decoded opc;
 367
 368       opcode_handle.pc = pc;
 369       bytes_read = msp430_decode_opcode (pc, &opc, msp430_get_opcode_byte,
 370                                          &opcode_handle);
 371       next_pc = pc + bytes_read;
 372
 373       if (opc.id == MSO_push && opc.op[0].type == MSP430_Operand_Register)
 374         {
 375           int rsrc = opc.op[0].reg;
 376
 377           reg[MSP430_SP_REGNUM] = pv_add_constant (reg[MSP430_SP_REGNUM], -2);
 378           stack.store (reg[MSP430_SP_REGNUM], 2, reg[rsrc]);
 379           after_last_frame_setup_insn = next_pc;
 380         }
 381       else if (opc.id == MSO_push       /* PUSHM  */
 382                && opc.op[0].type == MSP430_Operand_None
 383                && opc.op[1].type == MSP430_Operand_Register)
 384         {
 385           int rsrc = opc.op[1].reg;
 386           int count = opc.repeats + 1;
 387           int size = opc.size == 16 ? 2 : 4;
 388
 389           while (count > 0)
 390             {
 391               reg[MSP430_SP_REGNUM]
 392                 = pv_add_constant (reg[MSP430_SP_REGNUM], -size);
 393               stack.store (reg[MSP430_SP_REGNUM], size, reg[rsrc]);
 394               rsrc--;
 395               count--;
 396             }
 397           after_last_frame_setup_insn = next_pc;
 398         }
 399       else if (opc.id == MSO_sub
 400                && opc.op[0].type == MSP430_Operand_Register
 401                && opc.op[0].reg == MSR_SP
 402                && opc.op[1].type == MSP430_Operand_Immediate)
 403         {
 404           int addend = opc.op[1].addend;
 405
 406           reg[MSP430_SP_REGNUM] = pv_add_constant (reg[MSP430_SP_REGNUM],
 407                                                    -addend);
 408           after_last_frame_setup_insn = next_pc;
 409         }
 410       else if (opc.id == MSO_mov
 411                && opc.op[0].type == MSP430_Operand_Immediate
 412                && 12 <= opc.op[0].reg && opc.op[0].reg <= 15)
 413         after_last_frame_setup_insn = next_pc;
 414       else
 415         {
 416           /* Terminate the prologue scan.  */
 417           break;
 418         }
 419
 420       pc = next_pc;
 421     }
 422
 423   /* Is the frame size (offset, really) a known constant?  */
 424   if (pv_is_register (reg[MSP430_SP_REGNUM], MSP430_SP_REGNUM))
 425     result->frame_size = reg[MSP430_SP_REGNUM].k;
 426
 427   /* Record where all the registers were saved.  */
 428   stack.scan (check_for_saved, result);
 429
 430   result->prologue_end = after_last_frame_setup_insn;
 431 }
 432
 433 /* Implement the "skip_prologue" gdbarch method.  */
 434
 435 static CORE_ADDR
 436 msp430_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
 437 {
 438   const char *name;
 439   CORE_ADDR func_addr, func_end;
 440   struct msp430_prologue p;
 441
 442   /* Try to find the extent of the function that contains PC.  */
 443   if (!find_pc_partial_function (pc, &name, &func_addr, &func_end))
 444     return pc;
 445
 446   msp430_analyze_prologue (gdbarch, pc, func_end, &p);
 447   return p.prologue_end;
 448 }
 449
 450 /* Given a frame described by THIS_FRAME, decode the prologue of its
 451    associated function if there is not cache entry as specified by
 452    THIS_PROLOGUE_CACHE.  Save the decoded prologue in the cache and
 453    return that struct as the value of this function.  */
 454
 455 static struct msp430_prologue *
 456 msp430_analyze_frame_prologue (struct frame_info *this_frame,
 457                                void **this_prologue_cache)
 458 {
 459   if (!*this_prologue_cache)
 460     {
 461       CORE_ADDR func_start, stop_addr;
 462
 463       *this_prologue_cache = FRAME_OBSTACK_ZALLOC (struct msp430_prologue);
 464
 465       func_start = get_frame_func (this_frame);
 466       stop_addr = get_frame_pc (this_frame);
 467
 468       /* If we couldn't find any function containing the PC, then
 469          just initialize the prologue cache, but don't do anything.  */
 470       if (!func_start)
 471         stop_addr = func_start;
 472
 473       msp430_analyze_prologue (get_frame_arch (this_frame), func_start,
 474                                stop_addr,
 475                                (struct msp430_prologue *) *this_prologue_cache);
 476     }
 477
 478   return (struct msp430_prologue *) *this_prologue_cache;
 479 }
 480
 481 /* Given a frame and a prologue cache, return this frame's base.  */
 482
 483 static CORE_ADDR
 484 msp430_frame_base (struct frame_info *this_frame, void **this_prologue_cache)
 485 {
 486   struct msp430_prologue *p
 487     = msp430_analyze_frame_prologue (this_frame, this_prologue_cache);
 488   CORE_ADDR sp = get_frame_register_unsigned (this_frame, MSP430_SP_REGNUM);
 489
 490   return sp - p->frame_size;
 491 }
 492
 493 /* Implement the "frame_this_id" method for unwinding frames.  */
 494
 495 static void
 496 msp430_this_id (struct frame_info *this_frame,
 497                 void **this_prologue_cache, struct frame_id *this_id)
 498 {
 499   *this_id = frame_id_build (msp430_frame_base (this_frame,
 500                                                 this_prologue_cache),
 501                              get_frame_func (this_frame));
 502 }
 503
 504 /* Implement the "frame_prev_register" method for unwinding frames.  */
 505
 506 static struct value *
 507 msp430_prev_register (struct frame_info *this_frame,
 508                       void **this_prologue_cache, int regnum)
 509 {
 510   struct msp430_prologue *p
 511     = msp430_analyze_frame_prologue (this_frame, this_prologue_cache);
 512   CORE_ADDR frame_base = msp430_frame_base (this_frame, this_prologue_cache);
 513
 514   if (regnum == MSP430_SP_REGNUM)
 515     return frame_unwind_got_constant (this_frame, regnum, frame_base);
 516
 517   /* If prologue analysis says we saved this register somewhere,
 518      return a description of the stack slot holding it.  */
 519   else if (p->reg_offset[regnum] != 1)
 520     {
 521       struct value *rv = frame_unwind_got_memory (this_frame, regnum,
 522                                                   frame_base +
 523                                                   p->reg_offset[regnum]);
 524
 525       if (regnum == MSP430_PC_REGNUM)
 526         {
 527           ULONGEST pc = value_as_long (rv);
 528
 529           return frame_unwind_got_constant (this_frame, regnum, pc);
 530         }
 531       return rv;
 532     }
 533
 534   /* Otherwise, presume we haven't changed the value of this
 535      register, and get it from the next frame.  */
 536   else
 537     return frame_unwind_got_register (this_frame, regnum, regnum);
 538 }
 539
 540 static const struct frame_unwind msp430_unwind = {
 541   "msp430 prologue",
 542   NORMAL_FRAME,
 543   default_frame_unwind_stop_reason,
 544   msp430_this_id,
 545   msp430_prev_register,
 546   NULL,
 547   default_frame_sniffer
 548 };
 549
 550 /* Implement the "dwarf2_reg_to_regnum" gdbarch method.  */
 551
 552 static int
 553 msp430_dwarf2_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 554 {
 555   if (reg >= 0 && reg < MSP430_NUM_REGS)
 556     return reg + MSP430_NUM_REGS;
 557   return -1;
 558 }
 559
 560 /* Implement the "return_value" gdbarch method.  */
 561
 562 static enum return_value_convention
 563 msp430_return_value (struct gdbarch *gdbarch,
 564                      struct value *function,
 565                      struct type *valtype,
 566                      struct regcache *regcache,
 567                      gdb_byte *readbuf, const gdb_byte *writebuf)
 568 {
 569   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 570   LONGEST valtype_len = TYPE_LENGTH (valtype);
 571   int code_model = gdbarch_tdep (gdbarch)->code_model;
 572
 573   if (TYPE_LENGTH (valtype) > 8
 574       || valtype->code () == TYPE_CODE_STRUCT
 575       || valtype->code () == TYPE_CODE_UNION)
 576     return RETURN_VALUE_STRUCT_CONVENTION;
 577
 578   if (readbuf)
 579     {
 580       ULONGEST u;
 581       int argreg = MSP430_R12_REGNUM;
 582       int offset = 0;
 583
 584       while (valtype_len > 0)
 585         {
 586           int size = 2;
 587
 588           if (code_model == MSP_LARGE_CODE_MODEL
 589               && valtype->code () == TYPE_CODE_PTR)
 590             {
 591               size = 4;
 592             }
 593
 594           regcache_cooked_read_unsigned (regcache, argreg, &u);
 595           store_unsigned_integer (readbuf + offset, size, byte_order, u);
 596           valtype_len -= size;
 597           offset += size;
 598           argreg++;
 599         }
 600     }
 601
 602   if (writebuf)
 603     {
 604       ULONGEST u;
 605       int argreg = MSP430_R12_REGNUM;
 606       int offset = 0;
 607
 608       while (valtype_len > 0)
 609         {
 610           int size = 2;
 611
 612           if (code_model == MSP_LARGE_CODE_MODEL
 613               && valtype->code () == TYPE_CODE_PTR)
 614             {
 615               size = 4;
 616             }
 617
 618           u = extract_unsigned_integer (writebuf + offset, size, byte_order);
 619           regcache_cooked_write_unsigned (regcache, argreg, u);
 620           valtype_len -= size;
 621           offset += size;
 622           argreg++;
 623         }
 624     }
 625
 626   return RETURN_VALUE_REGISTER_CONVENTION;
 627 }
 628
 629
 630 /* Implement the "frame_align" gdbarch method.  */
 631
 632 static CORE_ADDR
 633 msp430_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
 634 {
 635   return align_down (sp, 2);
 636 }
 637
 638 /* Implement the "push_dummy_call" gdbarch method.  */
 639
 640 static CORE_ADDR
 641 msp430_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 642                         struct regcache *regcache, CORE_ADDR bp_addr,
 643                         int nargs, struct value **args, CORE_ADDR sp,
 644                         function_call_return_method return_method,
 645                         CORE_ADDR struct_addr)
 646 {
 647   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 648   int write_pass;
 649   int sp_off = 0;
 650   CORE_ADDR cfa;
 651   int code_model = gdbarch_tdep (gdbarch)->code_model;
 652
 653   struct type *func_type = value_type (function);
 654
 655   /* Dereference function pointer types.  */
 656   while (func_type->code () == TYPE_CODE_PTR)
 657     func_type = TYPE_TARGET_TYPE (func_type);
 658
 659   /* The end result had better be a function or a method.  */
 660   gdb_assert (func_type->code () == TYPE_CODE_FUNC
 661               || func_type->code () == TYPE_CODE_METHOD);
 662
 663   /* We make two passes; the first does the stack allocation,
 664      the second actually stores the arguments.  */
 665   for (write_pass = 0; write_pass <= 1; write_pass++)
 666     {
 667       int i;
 668       int arg_reg = MSP430_R12_REGNUM;
 669       int args_on_stack = 0;
 670
 671       if (write_pass)
 672         sp = align_down (sp - sp_off, 4);
 673       sp_off = 0;
 674
 675       if (return_method == return_method_struct)
 676         {
 677           if (write_pass)
 678             regcache_cooked_write_unsigned (regcache, arg_reg, struct_addr);
 679           arg_reg++;
 680         }
 681
 682       /* Push the arguments.  */
 683       for (i = 0; i < nargs; i++)
 684         {
 685           struct value *arg = args[i];
 686           const gdb_byte *arg_bits = value_contents_all (arg);
 687           struct type *arg_type = check_typedef (value_type (arg));
 688           ULONGEST arg_size = TYPE_LENGTH (arg_type);
 689           int offset;
 690           int current_arg_on_stack;
 691           gdb_byte struct_addr_buf[4];
 692
 693           current_arg_on_stack = 0;
 694
 695           if (arg_type->code () == TYPE_CODE_STRUCT
 696               || arg_type->code () == TYPE_CODE_UNION)
 697             {
 698               /* Aggregates of any size are passed by reference.  */
 699               store_unsigned_integer (struct_addr_buf, 4, byte_order,
 700                                       value_address (arg));
 701               arg_bits = struct_addr_buf;
 702               arg_size = (code_model == MSP_LARGE_CODE_MODEL) ? 4 : 2;
 703             }
 704           else
 705             {
 706               /* Scalars bigger than 8 bytes such as complex doubles are passed
 707                  on the stack.  */
 708               if (arg_size > 8)
 709                 current_arg_on_stack = 1;
 710             }
 711
 712
 713           for (offset = 0; offset < arg_size; offset += 2)
 714             {
 715               /* The condition below prevents 8 byte scalars from being split
 716                  between registers and memory (stack).  It also prevents other
 717                  splits once the stack has been written to.  */
 718               if (!current_arg_on_stack
 719                   && (arg_reg
 720                       + ((arg_size == 8 || args_on_stack)
 721                          ? ((arg_size - offset) / 2 - 1)
 722                          : 0) <= MSP430_R15_REGNUM))
 723                 {
 724                   int size = 2;
 725
 726                   if (code_model == MSP_LARGE_CODE_MODEL
 727                       && (arg_type->code () == TYPE_CODE_PTR
 728                           || TYPE_IS_REFERENCE (arg_type)
 729                           || arg_type->code () == TYPE_CODE_STRUCT
 730                           || arg_type->code () == TYPE_CODE_UNION))
 731                     {
 732                       /* When using the large memory model, pointer,
 733                          reference, struct, and union arguments are
 734                          passed using the entire register.  (As noted
 735                          earlier, aggregates are always passed by
 736                          reference.) */
 737                       if (offset != 0)
 738                         continue;
 739                       size = 4;
 740                     }
 741
 742                   if (write_pass)
 743                     regcache_cooked_write_unsigned (regcache, arg_reg,
 744                                                     extract_unsigned_integer
 745                                                     (arg_bits + offset, size,
 746                                                      byte_order));
 747
 748                   arg_reg++;
 749                 }
 750               else
 751                 {
 752                   if (write_pass)
 753                     write_memory (sp + sp_off, arg_bits + offset, 2);
 754
 755                   sp_off += 2;
 756                   args_on_stack = 1;
 757                   current_arg_on_stack = 1;
 758                 }
 759             }
 760         }
 761     }
 762
 763   /* Keep track of the stack address prior to pushing the return address.
 764      This is the value that we'll return.  */
 765   cfa = sp;
 766
 767   /* Push the return address.  */
 768   {
 769     int sz = (gdbarch_tdep (gdbarch)->code_model == MSP_SMALL_CODE_MODEL)
 770       ? 2 : 4;
 771     sp = sp - sz;
 772     write_memory_unsigned_integer (sp, sz, byte_order, bp_addr);
 773   }
 774
 775   /* Update the stack pointer.  */
 776   regcache_cooked_write_unsigned (regcache, MSP430_SP_REGNUM, sp);
 777
 778   return cfa;
 779 }
 780
 781 /* In order to keep code size small, the compiler may create epilogue
 782    code through which more than one function epilogue is routed.  I.e.
 783    the epilogue and return may just be a branch to some common piece of
 784    code which is responsible for tearing down the frame and performing
 785    the return.  These epilog (label) names will have the common prefix
 786    defined here.  */
 787
 788 static const char msp430_epilog_name_prefix[] = "__mspabi_func_epilog_";
 789
 790 /* Implement the "in_return_stub" gdbarch method.  */
 791
 792 static int
 793 msp430_in_return_stub (struct gdbarch *gdbarch, CORE_ADDR pc,
 794                        const char *name)
 795 {
 796   return (name != NULL
 797           && startswith (name, msp430_epilog_name_prefix));
 798 }
 799
 800 /* Implement the "skip_trampoline_code" gdbarch method.  */
 801 static CORE_ADDR
 802 msp430_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
 803 {
 804   struct bound_minimal_symbol bms;
 805   const char *stub_name;
 806   struct gdbarch *gdbarch = get_frame_arch (frame);
 807
 808   bms = lookup_minimal_symbol_by_pc (pc);
 809   if (!bms.minsym)
 810     return pc;
 811
 812   stub_name = bms.minsym->linkage_name ();
 813
 814   if (gdbarch_tdep (gdbarch)->code_model == MSP_SMALL_CODE_MODEL
 815       && msp430_in_return_stub (gdbarch, pc, stub_name))
 816     {
 817       CORE_ADDR sp = get_frame_register_unsigned (frame, MSP430_SP_REGNUM);
 818
 819       return read_memory_integer
 820         (sp + 2 * (stub_name[strlen (msp430_epilog_name_prefix)] - '0'),
 821          2, gdbarch_byte_order (gdbarch));
 822     }
 823
 824   return pc;
 825 }
 826
 827 /* Allocate and initialize a gdbarch object.  */
 828
 829 static struct gdbarch *
 830 msp430_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 831 {
 832   struct gdbarch *gdbarch;
 833   struct gdbarch_tdep *tdep;
 834   int elf_flags, isa, code_model;
 835
 836   /* Extract the elf_flags if available.  */
 837   if (info.abfd != NULL
 838       && bfd_get_flavour (info.abfd) == bfd_target_elf_flavour)
 839     elf_flags = elf_elfheader (info.abfd)->e_flags;
 840   else
 841     elf_flags = 0;
 842
 843   if (info.abfd != NULL)
 844     switch (bfd_elf_get_obj_attr_int (info.abfd, OBJ_ATTR_PROC,
 845                                       OFBA_MSPABI_Tag_ISA))
 846       {
 847       case 1:
 848         isa = MSP_ISA_MSP430;
 849         code_model = MSP_SMALL_CODE_MODEL;
 850         break;
 851       case 2:
 852         isa = MSP_ISA_MSP430X;
 853         switch (bfd_elf_get_obj_attr_int (info.abfd, OBJ_ATTR_PROC,
 854                                           OFBA_MSPABI_Tag_Code_Model))
 855           {
 856           case 1:
 857             code_model = MSP_SMALL_CODE_MODEL;
 858             break;
 859           case 2:
 860             code_model = MSP_LARGE_CODE_MODEL;
 861             break;
 862           default:
 863             internal_error (__FILE__, __LINE__,
 864                             _("Unknown msp430x code memory model"));
 865             break;
 866           }
 867         break;
 868       case 0:
 869         /* This can happen when loading a previously dumped data structure.
 870            Use the ISA and code model from the current architecture, provided
 871            it's compatible.  */
 872         {
 873           struct gdbarch *ca = get_current_arch ();
 874           if (ca && gdbarch_bfd_arch_info (ca)->arch == bfd_arch_msp430)
 875             {
 876               struct gdbarch_tdep *ca_tdep = gdbarch_tdep (ca);
 877
 878               elf_flags = ca_tdep->elf_flags;
 879               isa = ca_tdep->isa;
 880               code_model = ca_tdep->code_model;
 881               break;
 882             }
 883         }
 884         /* Fall through.  */
 885       default:
 886         error (_("Unknown msp430 isa"));
 887         break;
 888       }
 889   else
 890     {
 891       isa = MSP_ISA_MSP430;
 892       code_model = MSP_SMALL_CODE_MODEL;
 893     }
 894
 895
 896   /* Try to find the architecture in the list of already defined
 897      architectures.  */
 898   for (arches = gdbarch_list_lookup_by_info (arches, &info);
 899        arches != NULL;
 900        arches = gdbarch_list_lookup_by_info (arches->next, &info))
 901     {
 902       struct gdbarch_tdep *candidate_tdep = gdbarch_tdep (arches->gdbarch);
 903
 904       if (candidate_tdep->elf_flags != elf_flags
 905           || candidate_tdep->isa != isa
 906           || candidate_tdep->code_model != code_model)
 907         continue;
 908
 909       return arches->gdbarch;
 910     }
 911
 912   /* None found, create a new architecture from the information
 913      provided.  */
 914   tdep = XCNEW (struct gdbarch_tdep);
 915   gdbarch = gdbarch_alloc (&info, tdep);
 916   tdep->elf_flags = elf_flags;
 917   tdep->isa = isa;
 918   tdep->code_model = code_model;
 919
 920   /* Registers.  */
 921   set_gdbarch_num_regs (gdbarch, MSP430_NUM_REGS);
 922   set_gdbarch_num_pseudo_regs (gdbarch, MSP430_NUM_PSEUDO_REGS);
 923   set_gdbarch_register_name (gdbarch, msp430_register_name);
 924   if (isa == MSP_ISA_MSP430)
 925     set_gdbarch_register_type (gdbarch, msp430_register_type);
 926   else
 927     set_gdbarch_register_type (gdbarch, msp430x_register_type);
 928   set_gdbarch_pc_regnum (gdbarch, MSP430_PC_REGNUM);
 929   set_gdbarch_sp_regnum (gdbarch, MSP430_SP_REGNUM);
 930   set_gdbarch_register_reggroup_p (gdbarch, msp430_register_reggroup_p);
 931   set_gdbarch_pseudo_register_read (gdbarch, msp430_pseudo_register_read);
 932   set_gdbarch_pseudo_register_write (gdbarch, msp430_pseudo_register_write);
 933   set_gdbarch_dwarf2_reg_to_regnum (gdbarch, msp430_dwarf2_reg_to_regnum);
 934   set_gdbarch_register_sim_regno (gdbarch, msp430_register_sim_regno);
 935
 936   /* Data types.  */
 937   set_gdbarch_char_signed (gdbarch, 0);
 938   set_gdbarch_short_bit (gdbarch, 16);
 939   set_gdbarch_int_bit (gdbarch, 16);
 940   set_gdbarch_long_bit (gdbarch, 32);
 941   set_gdbarch_long_long_bit (gdbarch, 64);
 942   if (code_model == MSP_SMALL_CODE_MODEL)
 943     {
 944       set_gdbarch_ptr_bit (gdbarch, 16);
 945       set_gdbarch_addr_bit (gdbarch, 16);
 946     }
 947   else                          /* MSP_LARGE_CODE_MODEL */
 948     {
 949       set_gdbarch_ptr_bit (gdbarch, 32);
 950       set_gdbarch_addr_bit (gdbarch, 32);
 951     }
 952   set_gdbarch_dwarf2_addr_size (gdbarch, 4);
 953   set_gdbarch_float_bit (gdbarch, 32);
 954   set_gdbarch_float_format (gdbarch, floatformats_ieee_single);
 955   set_gdbarch_double_bit (gdbarch, 64);
 956   set_gdbarch_long_double_bit (gdbarch, 64);
 957   set_gdbarch_double_format (gdbarch, floatformats_ieee_double);
 958   set_gdbarch_long_double_format (gdbarch, floatformats_ieee_double);
 959
 960   /* Breakpoints.  */
 961   set_gdbarch_breakpoint_kind_from_pc (gdbarch,
 962                                        msp430_breakpoint::kind_from_pc);
 963   set_gdbarch_sw_breakpoint_from_kind (gdbarch,
 964                                        msp430_breakpoint::bp_from_kind);
 965   set_gdbarch_decr_pc_after_break (gdbarch, 1);
 966
 967   /* Frames, prologues, etc.  */
 968   set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
 969   set_gdbarch_skip_prologue (gdbarch, msp430_skip_prologue);
 970   set_gdbarch_frame_align (gdbarch, msp430_frame_align);
 971   dwarf2_append_unwinders (gdbarch);
 972   frame_unwind_append_unwinder (gdbarch, &msp430_unwind);
 973
 974   /* Dummy frames, return values.  */
 975   set_gdbarch_push_dummy_call (gdbarch, msp430_push_dummy_call);
 976   set_gdbarch_return_value (gdbarch, msp430_return_value);
 977
 978   /* Trampolines.  */
 979   set_gdbarch_in_solib_return_trampoline (gdbarch, msp430_in_return_stub);
 980   set_gdbarch_skip_trampoline_code (gdbarch, msp430_skip_trampoline_code);
 981
 982   /* Virtual tables.  */
 983   set_gdbarch_vbit_in_delta (gdbarch, 0);
 984
 985   return gdbarch;
 986 }
 987
 988 /* Register the initialization routine.  */
 989
 990 void _initialize_msp430_tdep ();
 991 void
 992 _initialize_msp430_tdep ()
 993 {
 994   register_gdbarch_init (bfd_arch_msp430, msp430_gdbarch_init);
 995 }