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[/] [or1k/] [trunk/] [gdb-5.3/] [gdb/] [alpha-tdep.c] - Blame information for rev 1773

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1 1181 sfurman
/* Target-dependent code for the ALPHA architecture, for GDB, the GNU Debugger.
2
   Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002
3
   Free Software Foundation, Inc.
4
 
5
   This file is part of GDB.
6
 
7
   This program is free software; you can redistribute it and/or modify
8
   it under the terms of the GNU General Public License as published by
9
   the Free Software Foundation; either version 2 of the License, or
10
   (at your option) any later version.
11
 
12
   This program is distributed in the hope that it will be useful,
13
   but WITHOUT ANY WARRANTY; without even the implied warranty of
14
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15
   GNU General Public License for more details.
16
 
17
   You should have received a copy of the GNU General Public License
18
   along with this program; if not, write to the Free Software
19
   Foundation, Inc., 59 Temple Place - Suite 330,
20
   Boston, MA 02111-1307, USA.  */
21
 
22
#include "defs.h"
23
#include "frame.h"
24
#include "inferior.h"
25
#include "symtab.h"
26
#include "value.h"
27
#include "gdbcmd.h"
28
#include "gdbcore.h"
29
#include "dis-asm.h"
30
#include "symfile.h"
31
#include "objfiles.h"
32
#include "gdb_string.h"
33
#include "linespec.h"
34
#include "regcache.h"
35
#include "doublest.h"
36
#include "arch-utils.h"
37
 
38
#include "elf-bfd.h"
39
 
40
#include "alpha-tdep.h"
41
 
42
static gdbarch_init_ftype alpha_gdbarch_init;
43
 
44
static gdbarch_register_name_ftype alpha_register_name;
45
static gdbarch_register_raw_size_ftype alpha_register_raw_size;
46
static gdbarch_register_virtual_size_ftype alpha_register_virtual_size;
47
static gdbarch_register_virtual_type_ftype alpha_register_virtual_type;
48
static gdbarch_register_byte_ftype alpha_register_byte;
49
static gdbarch_cannot_fetch_register_ftype alpha_cannot_fetch_register;
50
static gdbarch_cannot_store_register_ftype alpha_cannot_store_register;
51
static gdbarch_register_convertible_ftype alpha_register_convertible;
52
static gdbarch_register_convert_to_virtual_ftype
53
    alpha_register_convert_to_virtual;
54
static gdbarch_register_convert_to_raw_ftype alpha_register_convert_to_raw;
55
static gdbarch_store_struct_return_ftype alpha_store_struct_return;
56
static gdbarch_deprecated_extract_return_value_ftype alpha_extract_return_value;
57
static gdbarch_deprecated_extract_struct_value_address_ftype
58
    alpha_extract_struct_value_address;
59
static gdbarch_use_struct_convention_ftype alpha_use_struct_convention;
60
 
61
static gdbarch_breakpoint_from_pc_ftype alpha_breakpoint_from_pc;
62
 
63
static gdbarch_frame_args_address_ftype alpha_frame_args_address;
64
static gdbarch_frame_locals_address_ftype alpha_frame_locals_address;
65
 
66
static gdbarch_skip_prologue_ftype alpha_skip_prologue;
67
static gdbarch_saved_pc_after_call_ftype alpha_saved_pc_after_call;
68
static gdbarch_frame_chain_ftype alpha_frame_chain;
69
static gdbarch_frame_saved_pc_ftype alpha_frame_saved_pc;
70
static gdbarch_frame_init_saved_regs_ftype alpha_frame_init_saved_regs;
71
 
72
static gdbarch_push_arguments_ftype alpha_push_arguments;
73
static gdbarch_push_dummy_frame_ftype alpha_push_dummy_frame;
74
static gdbarch_pop_frame_ftype alpha_pop_frame;
75
static gdbarch_fix_call_dummy_ftype alpha_fix_call_dummy;
76
static gdbarch_init_frame_pc_first_ftype alpha_init_frame_pc_first;
77
static gdbarch_init_extra_frame_info_ftype alpha_init_extra_frame_info;
78
 
79
static gdbarch_get_longjmp_target_ftype alpha_get_longjmp_target;
80
 
81
struct frame_extra_info
82
  {
83
    alpha_extra_func_info_t proc_desc;
84
    int localoff;
85
    int pc_reg;
86
  };
87
 
88
/* FIXME: Some of this code should perhaps be merged with mips-tdep.c.  */
89
 
90
/* Prototypes for local functions. */
91
 
92
static void alpha_find_saved_regs (struct frame_info *);
93
 
94
static alpha_extra_func_info_t push_sigtramp_desc (CORE_ADDR low_addr);
95
 
96
static CORE_ADDR read_next_frame_reg (struct frame_info *, int);
97
 
98
static CORE_ADDR heuristic_proc_start (CORE_ADDR);
99
 
100
static alpha_extra_func_info_t heuristic_proc_desc (CORE_ADDR,
101
                                                    CORE_ADDR,
102
                                                    struct frame_info *);
103
 
104
static alpha_extra_func_info_t find_proc_desc (CORE_ADDR,
105
                                               struct frame_info *);
106
 
107
#if 0
108
static int alpha_in_lenient_prologue (CORE_ADDR, CORE_ADDR);
109
#endif
110
 
111
static void reinit_frame_cache_sfunc (char *, int, struct cmd_list_element *);
112
 
113
static CORE_ADDR after_prologue (CORE_ADDR pc,
114
                                 alpha_extra_func_info_t proc_desc);
115
 
116
static int alpha_in_prologue (CORE_ADDR pc,
117
                              alpha_extra_func_info_t proc_desc);
118
 
119
static int alpha_about_to_return (CORE_ADDR pc);
120
 
121
void _initialize_alpha_tdep (void);
122
 
123
/* Heuristic_proc_start may hunt through the text section for a long
124
   time across a 2400 baud serial line.  Allows the user to limit this
125
   search.  */
126
static unsigned int heuristic_fence_post = 0;
127
/* *INDENT-OFF* */
128
/* Layout of a stack frame on the alpha:
129
 
130
                |                               |
131
 pdr members:   |  7th ... nth arg,             |
132
                |  `pushed' by caller.          |
133
                |                               |
134
----------------|-------------------------------|<--  old_sp == vfp
135
   ^  ^  ^  ^   |                               |
136
   |  |  |  |   |                               |
137
   |  |localoff |  Copies of 1st .. 6th         |
138
   |  |  |  |   |  argument if necessary.       |
139
   |  |  |  v   |                               |
140
   |  |  |  --- |-------------------------------|<-- FRAME_LOCALS_ADDRESS
141
   |  |  |      |                               |
142
   |  |  |      |  Locals and temporaries.      |
143
   |  |  |      |                               |
144
   |  |  |      |-------------------------------|
145
   |  |  |      |                               |
146
   |-fregoffset |  Saved float registers.       |
147
   |  |  |      |  F9                           |
148
   |  |  |      |   .                           |
149
   |  |  |      |   .                           |
150
   |  |  |      |  F2                           |
151
   |  |  v      |                               |
152
   |  |  -------|-------------------------------|
153
   |  |         |                               |
154
   |  |         |  Saved registers.             |
155
   |  |         |  S6                           |
156
   |-regoffset  |   .                           |
157
   |  |         |   .                           |
158
   |  |         |  S0                           |
159
   |  |         |  pdr.pcreg                    |
160
   |  v         |                               |
161
   |  ----------|-------------------------------|
162
   |            |                               |
163
 frameoffset    |  Argument build area, gets    |
164
   |            |  7th ... nth arg for any      |
165
   |            |  called procedure.            |
166
   v            |                               |
167
   -------------|-------------------------------|<-- sp
168
                |                               |
169
*/
170
/* *INDENT-ON* */
171
 
172
#define PROC_LOW_ADDR(proc) ((proc)->pdr.adr)   /* least address */
173
/* These next two fields are kind of being hijacked.  I wonder if
174
   iline is too small for the values it needs to hold, if GDB is
175
   running on a 32-bit host.  */
176
#define PROC_HIGH_ADDR(proc) ((proc)->pdr.iline)        /* upper address bound */
177
#define PROC_DUMMY_FRAME(proc) ((proc)->pdr.cbLineOffset)       /*CALL_DUMMY frame */
178
#define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset)
179
#define PROC_FRAME_REG(proc) ((proc)->pdr.framereg)
180
#define PROC_REG_MASK(proc) ((proc)->pdr.regmask)
181
#define PROC_FREG_MASK(proc) ((proc)->pdr.fregmask)
182
#define PROC_REG_OFFSET(proc) ((proc)->pdr.regoffset)
183
#define PROC_FREG_OFFSET(proc) ((proc)->pdr.fregoffset)
184
#define PROC_PC_REG(proc) ((proc)->pdr.pcreg)
185
#define PROC_LOCALOFF(proc) ((proc)->pdr.localoff)
186
#define PROC_SYMBOL(proc) (*(struct symbol**)&(proc)->pdr.isym)
187
#define _PROC_MAGIC_ 0x0F0F0F0F
188
#define PROC_DESC_IS_DUMMY(proc) ((proc)->pdr.isym == _PROC_MAGIC_)
189
#define SET_PROC_DESC_IS_DUMMY(proc) ((proc)->pdr.isym = _PROC_MAGIC_)
190
 
191
struct linked_proc_info
192
  {
193
    struct alpha_extra_func_info info;
194
    struct linked_proc_info *next;
195
  }
196
 *linked_proc_desc_table = NULL;
197
 
198
static CORE_ADDR
199
alpha_frame_past_sigtramp_frame (struct frame_info *frame, CORE_ADDR pc)
200
{
201
  struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
202
 
203
  if (tdep->skip_sigtramp_frame != NULL)
204
    return (tdep->skip_sigtramp_frame (frame, pc));
205
 
206
  return (0);
207
}
208
 
209
static LONGEST
210
alpha_dynamic_sigtramp_offset (CORE_ADDR pc)
211
{
212
  struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
213
 
214
  /* Must be provided by OS/ABI variant code if supported. */
215
  if (tdep->dynamic_sigtramp_offset != NULL)
216
    return (tdep->dynamic_sigtramp_offset (pc));
217
 
218
  return (-1);
219
}
220
 
221
#define ALPHA_PROC_SIGTRAMP_MAGIC 0x0e0f0f0f
222
 
223
/* Return TRUE if the procedure descriptor PROC is a procedure
224
   descriptor that refers to a dynamically generated signal
225
   trampoline routine.  */
226
static int
227
alpha_proc_desc_is_dyn_sigtramp (struct alpha_extra_func_info *proc)
228
{
229
  struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
230
 
231
  if (tdep->dynamic_sigtramp_offset != NULL)
232
    return (proc->pdr.isym == ALPHA_PROC_SIGTRAMP_MAGIC);
233
 
234
  return (0);
235
}
236
 
237
static void
238
alpha_set_proc_desc_is_dyn_sigtramp (struct alpha_extra_func_info *proc)
239
{
240
  struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
241
 
242
  if (tdep->dynamic_sigtramp_offset != NULL)
243
    proc->pdr.isym = ALPHA_PROC_SIGTRAMP_MAGIC;
244
}
245
 
246
/* Dynamically create a signal-handler caller procedure descriptor for
247
   the signal-handler return code starting at address LOW_ADDR.  The
248
   descriptor is added to the linked_proc_desc_table.  */
249
 
250
static alpha_extra_func_info_t
251
push_sigtramp_desc (CORE_ADDR low_addr)
252
{
253
  struct linked_proc_info *link;
254
  alpha_extra_func_info_t proc_desc;
255
 
256
  link = (struct linked_proc_info *)
257
    xmalloc (sizeof (struct linked_proc_info));
258
  link->next = linked_proc_desc_table;
259
  linked_proc_desc_table = link;
260
 
261
  proc_desc = &link->info;
262
 
263
  proc_desc->numargs = 0;
264
  PROC_LOW_ADDR (proc_desc) = low_addr;
265
  PROC_HIGH_ADDR (proc_desc) = low_addr + 3 * 4;
266
  PROC_DUMMY_FRAME (proc_desc) = 0;
267
  PROC_FRAME_OFFSET (proc_desc) = 0x298;        /* sizeof(struct sigcontext_struct) */
268
  PROC_FRAME_REG (proc_desc) = SP_REGNUM;
269
  PROC_REG_MASK (proc_desc) = 0xffff;
270
  PROC_FREG_MASK (proc_desc) = 0xffff;
271
  PROC_PC_REG (proc_desc) = 26;
272
  PROC_LOCALOFF (proc_desc) = 0;
273
  alpha_set_proc_desc_is_dyn_sigtramp (proc_desc);
274
  return (proc_desc);
275
}
276
 
277
 
278
static const char *
279
alpha_register_name (int regno)
280
{
281
  static char *register_names[] =
282
  {
283
    "v0",   "t0",   "t1",   "t2",   "t3",   "t4",   "t5",   "t6",
284
    "t7",   "s0",   "s1",   "s2",   "s3",   "s4",   "s5",   "fp",
285
    "a0",   "a1",   "a2",   "a3",   "a4",   "a5",   "t8",   "t9",
286
    "t10",  "t11",  "ra",   "t12",  "at",   "gp",   "sp",   "zero",
287
    "f0",   "f1",   "f2",   "f3",   "f4",   "f5",   "f6",   "f7",
288
    "f8",   "f9",   "f10",  "f11",  "f12",  "f13",  "f14",  "f15",
289
    "f16",  "f17",  "f18",  "f19",  "f20",  "f21",  "f22",  "f23",
290
    "f24",  "f25",  "f26",  "f27",  "f28",  "f29",  "f30",  "fpcr",
291
    "pc",   "vfp",
292
  };
293
 
294
  if (regno < 0)
295
    return (NULL);
296
  if (regno >= (sizeof(register_names) / sizeof(*register_names)))
297
    return (NULL);
298
  return (register_names[regno]);
299
}
300
 
301
static int
302
alpha_cannot_fetch_register (int regno)
303
{
304
  return (regno == FP_REGNUM || regno == ALPHA_ZERO_REGNUM);
305
}
306
 
307
static int
308
alpha_cannot_store_register (int regno)
309
{
310
  return (regno == FP_REGNUM || regno == ALPHA_ZERO_REGNUM);
311
}
312
 
313
static int
314
alpha_register_convertible (int regno)
315
{
316
  return (regno >= FP0_REGNUM && regno <= FP0_REGNUM + 31);
317
}
318
 
319
static struct type *
320
alpha_register_virtual_type (int regno)
321
{
322
  return ((regno >= FP0_REGNUM && regno < (FP0_REGNUM+31))
323
          ? builtin_type_double : builtin_type_long);
324
}
325
 
326
static int
327
alpha_register_byte (int regno)
328
{
329
  return (regno * 8);
330
}
331
 
332
static int
333
alpha_register_raw_size (int regno)
334
{
335
  return 8;
336
}
337
 
338
static int
339
alpha_register_virtual_size (int regno)
340
{
341
  return 8;
342
}
343
 
344
 
345
static CORE_ADDR
346
alpha_sigcontext_addr (struct frame_info *fi)
347
{
348
  struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
349
 
350
  if (tdep->sigcontext_addr)
351
    return (tdep->sigcontext_addr (fi));
352
 
353
  return (0);
354
}
355
 
356
/* Guaranteed to set frame->saved_regs to some values (it never leaves it
357
   NULL).  */
358
 
359
static void
360
alpha_find_saved_regs (struct frame_info *frame)
361
{
362
  int ireg;
363
  CORE_ADDR reg_position;
364
  unsigned long mask;
365
  alpha_extra_func_info_t proc_desc;
366
  int returnreg;
367
 
368
  frame_saved_regs_zalloc (frame);
369
 
370
  /* If it is the frame for __sigtramp, the saved registers are located
371
     in a sigcontext structure somewhere on the stack. __sigtramp
372
     passes a pointer to the sigcontext structure on the stack.
373
     If the stack layout for __sigtramp changes, or if sigcontext offsets
374
     change, we might have to update this code.  */
375
#ifndef SIGFRAME_PC_OFF
376
#define SIGFRAME_PC_OFF         (2 * 8)
377
#define SIGFRAME_REGSAVE_OFF    (4 * 8)
378
#define SIGFRAME_FPREGSAVE_OFF  (SIGFRAME_REGSAVE_OFF + 32 * 8 + 8)
379
#endif
380
  if (frame->signal_handler_caller)
381
    {
382
      CORE_ADDR sigcontext_addr;
383
 
384
      sigcontext_addr = alpha_sigcontext_addr (frame);
385
      if (sigcontext_addr == 0)
386
        {
387
          /* Don't know where the sigcontext is; just bail.  */
388
          return;
389
        }
390
      for (ireg = 0; ireg < 32; ireg++)
391
        {
392
          reg_position = sigcontext_addr + SIGFRAME_REGSAVE_OFF + ireg * 8;
393
          frame->saved_regs[ireg] = reg_position;
394
        }
395
      for (ireg = 0; ireg < 32; ireg++)
396
        {
397
          reg_position = sigcontext_addr + SIGFRAME_FPREGSAVE_OFF + ireg * 8;
398
          frame->saved_regs[FP0_REGNUM + ireg] = reg_position;
399
        }
400
      frame->saved_regs[PC_REGNUM] = sigcontext_addr + SIGFRAME_PC_OFF;
401
      return;
402
    }
403
 
404
  proc_desc = frame->extra_info->proc_desc;
405
  if (proc_desc == NULL)
406
    /* I'm not sure how/whether this can happen.  Normally when we can't
407
       find a proc_desc, we "synthesize" one using heuristic_proc_desc
408
       and set the saved_regs right away.  */
409
    return;
410
 
411
  /* Fill in the offsets for the registers which gen_mask says
412
     were saved.  */
413
 
414
  reg_position = frame->frame + PROC_REG_OFFSET (proc_desc);
415
  mask = PROC_REG_MASK (proc_desc);
416
 
417
  returnreg = PROC_PC_REG (proc_desc);
418
 
419
  /* Note that RA is always saved first, regardless of its actual
420
     register number.  */
421
  if (mask & (1 << returnreg))
422
    {
423
      frame->saved_regs[returnreg] = reg_position;
424
      reg_position += 8;
425
      mask &= ~(1 << returnreg);        /* Clear bit for RA so we
426
                                           don't save again later. */
427
    }
428
 
429
  for (ireg = 0; ireg <= 31; ++ireg)
430
    if (mask & (1 << ireg))
431
      {
432
        frame->saved_regs[ireg] = reg_position;
433
        reg_position += 8;
434
      }
435
 
436
  /* Fill in the offsets for the registers which float_mask says
437
     were saved.  */
438
 
439
  reg_position = frame->frame + PROC_FREG_OFFSET (proc_desc);
440
  mask = PROC_FREG_MASK (proc_desc);
441
 
442
  for (ireg = 0; ireg <= 31; ++ireg)
443
    if (mask & (1 << ireg))
444
      {
445
        frame->saved_regs[FP0_REGNUM + ireg] = reg_position;
446
        reg_position += 8;
447
      }
448
 
449
  frame->saved_regs[PC_REGNUM] = frame->saved_regs[returnreg];
450
}
451
 
452
static void
453
alpha_frame_init_saved_regs (struct frame_info *fi)
454
{
455
  if (fi->saved_regs == NULL)
456
    alpha_find_saved_regs (fi);
457
  fi->saved_regs[SP_REGNUM] = fi->frame;
458
}
459
 
460
static void
461
alpha_init_frame_pc_first (int fromleaf, struct frame_info *prev)
462
{
463
  prev->pc = (fromleaf ? SAVED_PC_AFTER_CALL (prev->next) :
464
              prev->next ? FRAME_SAVED_PC (prev->next) : read_pc ());
465
}
466
 
467
static CORE_ADDR
468
read_next_frame_reg (struct frame_info *fi, int regno)
469
{
470
  for (; fi; fi = fi->next)
471
    {
472
      /* We have to get the saved sp from the sigcontext
473
         if it is a signal handler frame.  */
474
      if (regno == SP_REGNUM && !fi->signal_handler_caller)
475
        return fi->frame;
476
      else
477
        {
478
          if (fi->saved_regs == NULL)
479
            alpha_find_saved_regs (fi);
480
          if (fi->saved_regs[regno])
481
            return read_memory_integer (fi->saved_regs[regno], 8);
482
        }
483
    }
484
  return read_register (regno);
485
}
486
 
487
static CORE_ADDR
488
alpha_frame_saved_pc (struct frame_info *frame)
489
{
490
  alpha_extra_func_info_t proc_desc = frame->extra_info->proc_desc;
491
  /* We have to get the saved pc from the sigcontext
492
     if it is a signal handler frame.  */
493
  int pcreg = frame->signal_handler_caller ? PC_REGNUM
494
                                           : frame->extra_info->pc_reg;
495
 
496
  if (proc_desc && PROC_DESC_IS_DUMMY (proc_desc))
497
    return read_memory_integer (frame->frame - 8, 8);
498
 
499
  return read_next_frame_reg (frame, pcreg);
500
}
501
 
502
static CORE_ADDR
503
alpha_saved_pc_after_call (struct frame_info *frame)
504
{
505
  CORE_ADDR pc = frame->pc;
506
  CORE_ADDR tmp;
507
  alpha_extra_func_info_t proc_desc;
508
  int pcreg;
509
 
510
  /* Skip over shared library trampoline if necessary.  */
511
  tmp = SKIP_TRAMPOLINE_CODE (pc);
512
  if (tmp != 0)
513
    pc = tmp;
514
 
515
  proc_desc = find_proc_desc (pc, frame->next);
516
  pcreg = proc_desc ? PROC_PC_REG (proc_desc) : ALPHA_RA_REGNUM;
517
 
518
  if (frame->signal_handler_caller)
519
    return alpha_frame_saved_pc (frame);
520
  else
521
    return read_register (pcreg);
522
}
523
 
524
 
525
static struct alpha_extra_func_info temp_proc_desc;
526
static CORE_ADDR temp_saved_regs[ALPHA_NUM_REGS];
527
 
528
/* Nonzero if instruction at PC is a return instruction.  "ret
529
   $zero,($ra),1" on alpha. */
530
 
531
static int
532
alpha_about_to_return (CORE_ADDR pc)
533
{
534
  return read_memory_integer (pc, 4) == 0x6bfa8001;
535
}
536
 
537
 
538
 
539
/* This fencepost looks highly suspicious to me.  Removing it also
540
   seems suspicious as it could affect remote debugging across serial
541
   lines.  */
542
 
543
static CORE_ADDR
544
heuristic_proc_start (CORE_ADDR pc)
545
{
546
  struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
547
  CORE_ADDR start_pc = pc;
548
  CORE_ADDR fence = start_pc - heuristic_fence_post;
549
 
550
  if (start_pc == 0)
551
    return 0;
552
 
553
  if (heuristic_fence_post == UINT_MAX
554
      || fence < tdep->vm_min_address)
555
    fence = tdep->vm_min_address;
556
 
557
  /* search back for previous return */
558
  for (start_pc -= 4;; start_pc -= 4)
559
    if (start_pc < fence)
560
      {
561
        /* It's not clear to me why we reach this point when
562
           stop_soon_quietly, but with this test, at least we
563
           don't print out warnings for every child forked (eg, on
564
           decstation).  22apr93 rich@cygnus.com.  */
565
        if (!stop_soon_quietly)
566
          {
567
            static int blurb_printed = 0;
568
 
569
            if (fence == tdep->vm_min_address)
570
              warning ("Hit beginning of text section without finding");
571
            else
572
              warning ("Hit heuristic-fence-post without finding");
573
 
574
            warning ("enclosing function for address 0x%s", paddr_nz (pc));
575
            if (!blurb_printed)
576
              {
577
                printf_filtered ("\
578
This warning occurs if you are debugging a function without any symbols\n\
579
(for example, in a stripped executable).  In that case, you may wish to\n\
580
increase the size of the search with the `set heuristic-fence-post' command.\n\
581
\n\
582
Otherwise, you told GDB there was a function where there isn't one, or\n\
583
(more likely) you have encountered a bug in GDB.\n");
584
                blurb_printed = 1;
585
              }
586
          }
587
 
588
        return 0;
589
      }
590
    else if (alpha_about_to_return (start_pc))
591
      break;
592
 
593
  start_pc += 4;                /* skip return */
594
  return start_pc;
595
}
596
 
597
static alpha_extra_func_info_t
598
heuristic_proc_desc (CORE_ADDR start_pc, CORE_ADDR limit_pc,
599
                     struct frame_info *next_frame)
600
{
601
  CORE_ADDR sp = read_next_frame_reg (next_frame, SP_REGNUM);
602
  CORE_ADDR vfp = sp;
603
  CORE_ADDR cur_pc;
604
  int frame_size;
605
  int has_frame_reg = 0;
606
  unsigned long reg_mask = 0;
607
  int pcreg = -1;
608
  int regno;
609
 
610
  if (start_pc == 0)
611
    return NULL;
612
  memset (&temp_proc_desc, '\0', sizeof (temp_proc_desc));
613
  memset (&temp_saved_regs, '\0', SIZEOF_FRAME_SAVED_REGS);
614
  PROC_LOW_ADDR (&temp_proc_desc) = start_pc;
615
 
616
  if (start_pc + 200 < limit_pc)
617
    limit_pc = start_pc + 200;
618
  frame_size = 0;
619
  for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += 4)
620
    {
621
      char buf[4];
622
      unsigned long word;
623
      int status;
624
 
625
      status = read_memory_nobpt (cur_pc, buf, 4);
626
      if (status)
627
        memory_error (status, cur_pc);
628
      word = extract_unsigned_integer (buf, 4);
629
 
630
      if ((word & 0xffff0000) == 0x23de0000)    /* lda $sp,n($sp) */
631
        {
632
          if (word & 0x8000)
633
          {
634
            /* Consider only the first stack allocation instruction
635
               to contain the static size of the frame. */
636
            if (frame_size == 0)
637
                frame_size += (-word) & 0xffff;
638
          }
639
          else
640
            /* Exit loop if a positive stack adjustment is found, which
641
               usually means that the stack cleanup code in the function
642
               epilogue is reached.  */
643
            break;
644
        }
645
      else if ((word & 0xfc1f0000) == 0xb41e0000        /* stq reg,n($sp) */
646
               && (word & 0xffff0000) != 0xb7fe0000)    /* reg != $zero */
647
        {
648
          int reg = (word & 0x03e00000) >> 21;
649
          reg_mask |= 1 << reg;
650
 
651
          /* Do not compute the address where the register was saved yet,
652
             because we don't know yet if the offset will need to be
653
             relative to $sp or $fp (we can not compute the address relative
654
             to $sp if $sp is updated during the execution of the current
655
             subroutine, for instance when doing some alloca). So just store
656
             the offset for the moment, and compute the address later
657
             when we know whether this frame has a frame pointer or not.
658
           */
659
          temp_saved_regs[reg] = (short) word;
660
 
661
          /* Starting with OSF/1-3.2C, the system libraries are shipped
662
             without local symbols, but they still contain procedure
663
             descriptors without a symbol reference. GDB is currently
664
             unable to find these procedure descriptors and uses
665
             heuristic_proc_desc instead.
666
             As some low level compiler support routines (__div*, __add*)
667
             use a non-standard return address register, we have to
668
             add some heuristics to determine the return address register,
669
             or stepping over these routines will fail.
670
             Usually the return address register is the first register
671
             saved on the stack, but assembler optimization might
672
             rearrange the register saves.
673
             So we recognize only a few registers (t7, t9, ra) within
674
             the procedure prologue as valid return address registers.
675
             If we encounter a return instruction, we extract the
676
             the return address register from it.
677
 
678
             FIXME: Rewriting GDB to access the procedure descriptors,
679
             e.g. via the minimal symbol table, might obviate this hack.  */
680
          if (pcreg == -1
681
              && cur_pc < (start_pc + 80)
682
              && (reg == ALPHA_T7_REGNUM || reg == ALPHA_T9_REGNUM
683
                  || reg == ALPHA_RA_REGNUM))
684
            pcreg = reg;
685
        }
686
      else if ((word & 0xffe0ffff) == 0x6be08001)       /* ret zero,reg,1 */
687
        pcreg = (word >> 16) & 0x1f;
688
      else if (word == 0x47de040f || word == 0x47fe040f) /* bis sp,sp fp */
689
        {
690
          /* ??? I am not sure what instruction is 0x47fe040f, and I
691
             am suspecting that there was a typo and should have been
692
             0x47fe040f. I'm keeping it in the test above until further
693
             investigation */
694
            has_frame_reg = 1;
695
          vfp = read_next_frame_reg (next_frame, ALPHA_GCC_FP_REGNUM);
696
        }
697
    }
698
  if (pcreg == -1)
699
    {
700
      /* If we haven't found a valid return address register yet,
701
         keep searching in the procedure prologue.  */
702
      while (cur_pc < (limit_pc + 80) && cur_pc < (start_pc + 80))
703
        {
704
          char buf[4];
705
          unsigned long word;
706
 
707
          if (read_memory_nobpt (cur_pc, buf, 4))
708
            break;
709
          cur_pc += 4;
710
          word = extract_unsigned_integer (buf, 4);
711
 
712
          if ((word & 0xfc1f0000) == 0xb41e0000         /* stq reg,n($sp) */
713
              && (word & 0xffff0000) != 0xb7fe0000)     /* reg != $zero */
714
            {
715
              int reg = (word & 0x03e00000) >> 21;
716
              if (reg == ALPHA_T7_REGNUM || reg == ALPHA_T9_REGNUM
717
                  || reg == ALPHA_RA_REGNUM)
718
                {
719
                  pcreg = reg;
720
                  break;
721
                }
722
            }
723
          else if ((word & 0xffe0ffff) == 0x6be08001)   /* ret zero,reg,1 */
724
            {
725
              pcreg = (word >> 16) & 0x1f;
726
              break;
727
            }
728
        }
729
    }
730
 
731
  if (has_frame_reg)
732
    PROC_FRAME_REG (&temp_proc_desc) = ALPHA_GCC_FP_REGNUM;
733
  else
734
    PROC_FRAME_REG (&temp_proc_desc) = SP_REGNUM;
735
 
736
  /* At this point, we know which of the Stack Pointer or the Frame Pointer
737
     to use as the reference address to compute the saved registers address.
738
     But in both cases, the processing above has set vfp to this reference
739
     address, so just need to increment the offset of each saved register
740
     by this address. */
741
  for (regno = 0; regno < NUM_REGS; regno++)
742
    {
743
      if (reg_mask & 1 << regno)
744
        temp_saved_regs[regno] += vfp;
745
    }
746
 
747
  PROC_FRAME_OFFSET (&temp_proc_desc) = frame_size;
748
  PROC_REG_MASK (&temp_proc_desc) = reg_mask;
749
  PROC_PC_REG (&temp_proc_desc) = (pcreg == -1) ? ALPHA_RA_REGNUM : pcreg;
750
  PROC_LOCALOFF (&temp_proc_desc) = 0;   /* XXX - bogus */
751
  return &temp_proc_desc;
752
}
753
 
754
/* This returns the PC of the first inst after the prologue.  If we can't
755
   find the prologue, then return 0.  */
756
 
757
static CORE_ADDR
758
after_prologue (CORE_ADDR pc, alpha_extra_func_info_t proc_desc)
759
{
760
  struct symtab_and_line sal;
761
  CORE_ADDR func_addr, func_end;
762
 
763
  if (!proc_desc)
764
    proc_desc = find_proc_desc (pc, NULL);
765
 
766
  if (proc_desc)
767
    {
768
      if (alpha_proc_desc_is_dyn_sigtramp (proc_desc))
769
        return PROC_LOW_ADDR (proc_desc);       /* "prologue" is in kernel */
770
 
771
      /* If function is frameless, then we need to do it the hard way.  I
772
         strongly suspect that frameless always means prologueless... */
773
      if (PROC_FRAME_REG (proc_desc) == SP_REGNUM
774
          && PROC_FRAME_OFFSET (proc_desc) == 0)
775
        return 0;
776
    }
777
 
778
  if (!find_pc_partial_function (pc, NULL, &func_addr, &func_end))
779
    return 0;                    /* Unknown */
780
 
781
  sal = find_pc_line (func_addr, 0);
782
 
783
  if (sal.end < func_end)
784
    return sal.end;
785
 
786
  /* The line after the prologue is after the end of the function.  In this
787
     case, tell the caller to find the prologue the hard way.  */
788
 
789
  return 0;
790
}
791
 
792
/* Return non-zero if we *might* be in a function prologue.  Return zero if we
793
   are definitively *not* in a function prologue.  */
794
 
795
static int
796
alpha_in_prologue (CORE_ADDR pc, alpha_extra_func_info_t proc_desc)
797
{
798
  CORE_ADDR after_prologue_pc;
799
 
800
  after_prologue_pc = after_prologue (pc, proc_desc);
801
 
802
  if (after_prologue_pc == 0
803
      || pc < after_prologue_pc)
804
    return 1;
805
  else
806
    return 0;
807
}
808
 
809
static alpha_extra_func_info_t
810
find_proc_desc (CORE_ADDR pc, struct frame_info *next_frame)
811
{
812
  alpha_extra_func_info_t proc_desc;
813
  struct block *b;
814
  struct symbol *sym;
815
  CORE_ADDR startaddr;
816
 
817
  /* Try to get the proc_desc from the linked call dummy proc_descs
818
     if the pc is in the call dummy.
819
     This is hairy. In the case of nested dummy calls we have to find the
820
     right proc_desc, but we might not yet know the frame for the dummy
821
     as it will be contained in the proc_desc we are searching for.
822
     So we have to find the proc_desc whose frame is closest to the current
823
     stack pointer.  */
824
 
825
  if (PC_IN_CALL_DUMMY (pc, 0, 0))
826
    {
827
      struct linked_proc_info *link;
828
      CORE_ADDR sp = read_next_frame_reg (next_frame, SP_REGNUM);
829
      alpha_extra_func_info_t found_proc_desc = NULL;
830
      long min_distance = LONG_MAX;
831
 
832
      for (link = linked_proc_desc_table; link; link = link->next)
833
        {
834
          long distance = (CORE_ADDR) PROC_DUMMY_FRAME (&link->info) - sp;
835
          if (distance > 0 && distance < min_distance)
836
            {
837
              min_distance = distance;
838
              found_proc_desc = &link->info;
839
            }
840
        }
841
      if (found_proc_desc != NULL)
842
        return found_proc_desc;
843
    }
844
 
845
  b = block_for_pc (pc);
846
 
847
  find_pc_partial_function (pc, NULL, &startaddr, NULL);
848
  if (b == NULL)
849
    sym = NULL;
850
  else
851
    {
852
      if (startaddr > BLOCK_START (b))
853
        /* This is the "pathological" case referred to in a comment in
854
           print_frame_info.  It might be better to move this check into
855
           symbol reading.  */
856
        sym = NULL;
857
      else
858
        sym = lookup_symbol (MIPS_EFI_SYMBOL_NAME, b, LABEL_NAMESPACE,
859
                             0, NULL);
860
    }
861
 
862
  /* If we never found a PDR for this function in symbol reading, then
863
     examine prologues to find the information.  */
864
  if (sym && ((mips_extra_func_info_t) SYMBOL_VALUE (sym))->pdr.framereg == -1)
865
    sym = NULL;
866
 
867
  if (sym)
868
    {
869
      /* IF this is the topmost frame AND
870
       * (this proc does not have debugging information OR
871
       * the PC is in the procedure prologue)
872
       * THEN create a "heuristic" proc_desc (by analyzing
873
       * the actual code) to replace the "official" proc_desc.
874
       */
875
      proc_desc = (alpha_extra_func_info_t) SYMBOL_VALUE (sym);
876
      if (next_frame == NULL)
877
        {
878
          if (PROC_DESC_IS_DUMMY (proc_desc) || alpha_in_prologue (pc, proc_desc))
879
            {
880
              alpha_extra_func_info_t found_heuristic =
881
              heuristic_proc_desc (PROC_LOW_ADDR (proc_desc),
882
                                   pc, next_frame);
883
              if (found_heuristic)
884
                {
885
                  PROC_LOCALOFF (found_heuristic) =
886
                    PROC_LOCALOFF (proc_desc);
887
                  PROC_PC_REG (found_heuristic) = PROC_PC_REG (proc_desc);
888
                  proc_desc = found_heuristic;
889
                }
890
            }
891
        }
892
    }
893
  else
894
    {
895
      long offset;
896
 
897
      /* Is linked_proc_desc_table really necessary?  It only seems to be used
898
         by procedure call dummys.  However, the procedures being called ought
899
         to have their own proc_descs, and even if they don't,
900
         heuristic_proc_desc knows how to create them! */
901
 
902
      register struct linked_proc_info *link;
903
      for (link = linked_proc_desc_table; link; link = link->next)
904
        if (PROC_LOW_ADDR (&link->info) <= pc
905
            && PROC_HIGH_ADDR (&link->info) > pc)
906
          return &link->info;
907
 
908
      /* If PC is inside a dynamically generated sigtramp handler,
909
         create and push a procedure descriptor for that code: */
910
      offset = alpha_dynamic_sigtramp_offset (pc);
911
      if (offset >= 0)
912
        return push_sigtramp_desc (pc - offset);
913
 
914
      /* If heuristic_fence_post is non-zero, determine the procedure
915
         start address by examining the instructions.
916
         This allows us to find the start address of static functions which
917
         have no symbolic information, as startaddr would have been set to
918
         the preceding global function start address by the
919
         find_pc_partial_function call above.  */
920
      if (startaddr == 0 || heuristic_fence_post != 0)
921
        startaddr = heuristic_proc_start (pc);
922
 
923
      proc_desc =
924
        heuristic_proc_desc (startaddr, pc, next_frame);
925
    }
926
  return proc_desc;
927
}
928
 
929
alpha_extra_func_info_t cached_proc_desc;
930
 
931
static CORE_ADDR
932
alpha_frame_chain (struct frame_info *frame)
933
{
934
  alpha_extra_func_info_t proc_desc;
935
  CORE_ADDR saved_pc = FRAME_SAVED_PC (frame);
936
 
937
  if (saved_pc == 0 || inside_entry_file (saved_pc))
938
    return 0;
939
 
940
  proc_desc = find_proc_desc (saved_pc, frame);
941
  if (!proc_desc)
942
    return 0;
943
 
944
  cached_proc_desc = proc_desc;
945
 
946
  /* Fetch the frame pointer for a dummy frame from the procedure
947
     descriptor.  */
948
  if (PROC_DESC_IS_DUMMY (proc_desc))
949
    return (CORE_ADDR) PROC_DUMMY_FRAME (proc_desc);
950
 
951
  /* If no frame pointer and frame size is zero, we must be at end
952
     of stack (or otherwise hosed).  If we don't check frame size,
953
     we loop forever if we see a zero size frame.  */
954
  if (PROC_FRAME_REG (proc_desc) == SP_REGNUM
955
      && PROC_FRAME_OFFSET (proc_desc) == 0
956
  /* The previous frame from a sigtramp frame might be frameless
957
     and have frame size zero.  */
958
      && !frame->signal_handler_caller)
959
    return alpha_frame_past_sigtramp_frame (frame, saved_pc);
960
  else
961
    return read_next_frame_reg (frame, PROC_FRAME_REG (proc_desc))
962
      + PROC_FRAME_OFFSET (proc_desc);
963
}
964
 
965
void
966
alpha_print_extra_frame_info (struct frame_info *fi)
967
{
968
  if (fi
969
      && fi->extra_info
970
      && fi->extra_info->proc_desc
971
      && fi->extra_info->proc_desc->pdr.framereg < NUM_REGS)
972
    printf_filtered (" frame pointer is at %s+%s\n",
973
                     REGISTER_NAME (fi->extra_info->proc_desc->pdr.framereg),
974
                     paddr_d (fi->extra_info->proc_desc->pdr.frameoffset));
975
}
976
 
977
static void
978
alpha_init_extra_frame_info (int fromleaf, struct frame_info *frame)
979
{
980
  /* Use proc_desc calculated in frame_chain */
981
  alpha_extra_func_info_t proc_desc =
982
  frame->next ? cached_proc_desc : find_proc_desc (frame->pc, frame->next);
983
 
984
  frame->extra_info = (struct frame_extra_info *)
985
    frame_obstack_alloc (sizeof (struct frame_extra_info));
986
 
987
  frame->saved_regs = NULL;
988
  frame->extra_info->localoff = 0;
989
  frame->extra_info->pc_reg = ALPHA_RA_REGNUM;
990
  frame->extra_info->proc_desc = proc_desc == &temp_proc_desc ? 0 : proc_desc;
991
  if (proc_desc)
992
    {
993
      /* Get the locals offset and the saved pc register from the
994
         procedure descriptor, they are valid even if we are in the
995
         middle of the prologue.  */
996
      frame->extra_info->localoff = PROC_LOCALOFF (proc_desc);
997
      frame->extra_info->pc_reg = PROC_PC_REG (proc_desc);
998
 
999
      /* Fixup frame-pointer - only needed for top frame */
1000
 
1001
      /* Fetch the frame pointer for a dummy frame from the procedure
1002
         descriptor.  */
1003
      if (PROC_DESC_IS_DUMMY (proc_desc))
1004
        frame->frame = (CORE_ADDR) PROC_DUMMY_FRAME (proc_desc);
1005
 
1006
      /* This may not be quite right, if proc has a real frame register.
1007
         Get the value of the frame relative sp, procedure might have been
1008
         interrupted by a signal at it's very start.  */
1009
      else if (frame->pc == PROC_LOW_ADDR (proc_desc)
1010
               && !alpha_proc_desc_is_dyn_sigtramp (proc_desc))
1011
        frame->frame = read_next_frame_reg (frame->next, SP_REGNUM);
1012
      else
1013
        frame->frame = read_next_frame_reg (frame->next, PROC_FRAME_REG (proc_desc))
1014
          + PROC_FRAME_OFFSET (proc_desc);
1015
 
1016
      if (proc_desc == &temp_proc_desc)
1017
        {
1018
          char *name;
1019
 
1020
          /* Do not set the saved registers for a sigtramp frame,
1021
             alpha_find_saved_registers will do that for us.
1022
             We can't use frame->signal_handler_caller, it is not yet set.  */
1023
          find_pc_partial_function (frame->pc, &name,
1024
                                    (CORE_ADDR *) NULL, (CORE_ADDR *) NULL);
1025
          if (!PC_IN_SIGTRAMP (frame->pc, name))
1026
            {
1027
              frame->saved_regs = (CORE_ADDR *)
1028
                frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS);
1029
              memcpy (frame->saved_regs, temp_saved_regs,
1030
                      SIZEOF_FRAME_SAVED_REGS);
1031
              frame->saved_regs[PC_REGNUM]
1032
                = frame->saved_regs[ALPHA_RA_REGNUM];
1033
            }
1034
        }
1035
    }
1036
}
1037
 
1038
static CORE_ADDR
1039
alpha_frame_locals_address (struct frame_info *fi)
1040
{
1041
  return (fi->frame - fi->extra_info->localoff);
1042
}
1043
 
1044
static CORE_ADDR
1045
alpha_frame_args_address (struct frame_info *fi)
1046
{
1047
  return (fi->frame - (ALPHA_NUM_ARG_REGS * 8));
1048
}
1049
 
1050
/* ALPHA stack frames are almost impenetrable.  When execution stops,
1051
   we basically have to look at symbol information for the function
1052
   that we stopped in, which tells us *which* register (if any) is
1053
   the base of the frame pointer, and what offset from that register
1054
   the frame itself is at.
1055
 
1056
   This presents a problem when trying to examine a stack in memory
1057
   (that isn't executing at the moment), using the "frame" command.  We
1058
   don't have a PC, nor do we have any registers except SP.
1059
 
1060
   This routine takes two arguments, SP and PC, and tries to make the
1061
   cached frames look as if these two arguments defined a frame on the
1062
   cache.  This allows the rest of info frame to extract the important
1063
   arguments without difficulty.  */
1064
 
1065
struct frame_info *
1066
alpha_setup_arbitrary_frame (int argc, CORE_ADDR *argv)
1067
{
1068
  if (argc != 2)
1069
    error ("ALPHA frame specifications require two arguments: sp and pc");
1070
 
1071
  return create_new_frame (argv[0], argv[1]);
1072
}
1073
 
1074
/* The alpha passes the first six arguments in the registers, the rest on
1075
   the stack. The register arguments are eventually transferred to the
1076
   argument transfer area immediately below the stack by the called function
1077
   anyway. So we `push' at least six arguments on the stack, `reload' the
1078
   argument registers and then adjust the stack pointer to point past the
1079
   sixth argument. This algorithm simplifies the passing of a large struct
1080
   which extends from the registers to the stack.
1081
   If the called function is returning a structure, the address of the
1082
   structure to be returned is passed as a hidden first argument.  */
1083
 
1084
static CORE_ADDR
1085
alpha_push_arguments (int nargs, struct value **args, CORE_ADDR sp,
1086
                      int struct_return, CORE_ADDR struct_addr)
1087
{
1088
  int i;
1089
  int accumulate_size = struct_return ? 8 : 0;
1090
  int arg_regs_size = ALPHA_NUM_ARG_REGS * 8;
1091
  struct alpha_arg
1092
    {
1093
      char *contents;
1094
      int len;
1095
      int offset;
1096
    };
1097
  struct alpha_arg *alpha_args =
1098
  (struct alpha_arg *) alloca (nargs * sizeof (struct alpha_arg));
1099
  register struct alpha_arg *m_arg;
1100
  char raw_buffer[sizeof (CORE_ADDR)];
1101
  int required_arg_regs;
1102
 
1103
  for (i = 0, m_arg = alpha_args; i < nargs; i++, m_arg++)
1104
    {
1105
      struct value *arg = args[i];
1106
      struct type *arg_type = check_typedef (VALUE_TYPE (arg));
1107
      /* Cast argument to long if necessary as the compiler does it too.  */
1108
      switch (TYPE_CODE (arg_type))
1109
        {
1110
        case TYPE_CODE_INT:
1111
        case TYPE_CODE_BOOL:
1112
        case TYPE_CODE_CHAR:
1113
        case TYPE_CODE_RANGE:
1114
        case TYPE_CODE_ENUM:
1115
          if (TYPE_LENGTH (arg_type) < TYPE_LENGTH (builtin_type_long))
1116
            {
1117
              arg_type = builtin_type_long;
1118
              arg = value_cast (arg_type, arg);
1119
            }
1120
          break;
1121
        default:
1122
          break;
1123
        }
1124
      m_arg->len = TYPE_LENGTH (arg_type);
1125
      m_arg->offset = accumulate_size;
1126
      accumulate_size = (accumulate_size + m_arg->len + 7) & ~7;
1127
      m_arg->contents = VALUE_CONTENTS (arg);
1128
    }
1129
 
1130
  /* Determine required argument register loads, loading an argument register
1131
     is expensive as it uses three ptrace calls.  */
1132
  required_arg_regs = accumulate_size / 8;
1133
  if (required_arg_regs > ALPHA_NUM_ARG_REGS)
1134
    required_arg_regs = ALPHA_NUM_ARG_REGS;
1135
 
1136
  /* Make room for the arguments on the stack.  */
1137
  if (accumulate_size < arg_regs_size)
1138
    accumulate_size = arg_regs_size;
1139
  sp -= accumulate_size;
1140
 
1141
  /* Keep sp aligned to a multiple of 16 as the compiler does it too.  */
1142
  sp &= ~15;
1143
 
1144
  /* `Push' arguments on the stack.  */
1145
  for (i = nargs; m_arg--, --i >= 0;)
1146
    write_memory (sp + m_arg->offset, m_arg->contents, m_arg->len);
1147
  if (struct_return)
1148
    {
1149
      store_address (raw_buffer, sizeof (CORE_ADDR), struct_addr);
1150
      write_memory (sp, raw_buffer, sizeof (CORE_ADDR));
1151
    }
1152
 
1153
  /* Load the argument registers.  */
1154
  for (i = 0; i < required_arg_regs; i++)
1155
    {
1156
      LONGEST val;
1157
 
1158
      val = read_memory_integer (sp + i * 8, 8);
1159
      write_register (ALPHA_A0_REGNUM + i, val);
1160
      write_register (ALPHA_FPA0_REGNUM + i, val);
1161
    }
1162
 
1163
  return sp + arg_regs_size;
1164
}
1165
 
1166
static void
1167
alpha_push_dummy_frame (void)
1168
{
1169
  int ireg;
1170
  struct linked_proc_info *link;
1171
  alpha_extra_func_info_t proc_desc;
1172
  CORE_ADDR sp = read_register (SP_REGNUM);
1173
  CORE_ADDR save_address;
1174
  char raw_buffer[ALPHA_MAX_REGISTER_RAW_SIZE];
1175
  unsigned long mask;
1176
 
1177
  link = (struct linked_proc_info *) xmalloc (sizeof (struct linked_proc_info));
1178
  link->next = linked_proc_desc_table;
1179
  linked_proc_desc_table = link;
1180
 
1181
  proc_desc = &link->info;
1182
 
1183
  /*
1184
   * The registers we must save are all those not preserved across
1185
   * procedure calls.
1186
   * In addition, we must save the PC and RA.
1187
   *
1188
   * Dummy frame layout:
1189
   *  (high memory)
1190
   *    Saved PC
1191
   *    Saved F30
1192
   *    ...
1193
   *    Saved F0
1194
   *    Saved R29
1195
   *    ...
1196
   *    Saved R0
1197
   *    Saved R26 (RA)
1198
   *    Parameter build area
1199
   *  (low memory)
1200
   */
1201
 
1202
/* MASK(i,j) == (1<<i) + (1<<(i+1)) + ... + (1<<j)). Assume i<=j<31. */
1203
#define MASK(i,j) ((((LONGEST)1 << ((j)+1)) - 1) ^ (((LONGEST)1 << (i)) - 1))
1204
#define GEN_REG_SAVE_MASK (MASK(0,8) | MASK(16,29))
1205
#define GEN_REG_SAVE_COUNT 24
1206
#define FLOAT_REG_SAVE_MASK (MASK(0,1) | MASK(10,30))
1207
#define FLOAT_REG_SAVE_COUNT 23
1208
  /* The special register is the PC as we have no bit for it in the save masks.
1209
     alpha_frame_saved_pc knows where the pc is saved in a dummy frame.  */
1210
#define SPECIAL_REG_SAVE_COUNT 1
1211
 
1212
  PROC_REG_MASK (proc_desc) = GEN_REG_SAVE_MASK;
1213
  PROC_FREG_MASK (proc_desc) = FLOAT_REG_SAVE_MASK;
1214
  /* PROC_REG_OFFSET is the offset from the dummy frame to the saved RA,
1215
     but keep SP aligned to a multiple of 16.  */
1216
  PROC_REG_OFFSET (proc_desc) =
1217
    -((8 * (SPECIAL_REG_SAVE_COUNT
1218
            + GEN_REG_SAVE_COUNT
1219
            + FLOAT_REG_SAVE_COUNT)
1220
       + 15) & ~15);
1221
  PROC_FREG_OFFSET (proc_desc) =
1222
    PROC_REG_OFFSET (proc_desc) + 8 * GEN_REG_SAVE_COUNT;
1223
 
1224
  /* Save general registers.
1225
     The return address register is the first saved register, all other
1226
     registers follow in ascending order.
1227
     The PC is saved immediately below the SP.  */
1228
  save_address = sp + PROC_REG_OFFSET (proc_desc);
1229
  store_address (raw_buffer, 8, read_register (ALPHA_RA_REGNUM));
1230
  write_memory (save_address, raw_buffer, 8);
1231
  save_address += 8;
1232
  mask = PROC_REG_MASK (proc_desc) & 0xffffffffL;
1233
  for (ireg = 0; mask; ireg++, mask >>= 1)
1234
    if (mask & 1)
1235
      {
1236
        if (ireg == ALPHA_RA_REGNUM)
1237
          continue;
1238
        store_address (raw_buffer, 8, read_register (ireg));
1239
        write_memory (save_address, raw_buffer, 8);
1240
        save_address += 8;
1241
      }
1242
 
1243
  store_address (raw_buffer, 8, read_register (PC_REGNUM));
1244
  write_memory (sp - 8, raw_buffer, 8);
1245
 
1246
  /* Save floating point registers.  */
1247
  save_address = sp + PROC_FREG_OFFSET (proc_desc);
1248
  mask = PROC_FREG_MASK (proc_desc) & 0xffffffffL;
1249
  for (ireg = 0; mask; ireg++, mask >>= 1)
1250
    if (mask & 1)
1251
      {
1252
        store_address (raw_buffer, 8, read_register (ireg + FP0_REGNUM));
1253
        write_memory (save_address, raw_buffer, 8);
1254
        save_address += 8;
1255
      }
1256
 
1257
  /* Set and save the frame address for the dummy.
1258
     This is tricky. The only registers that are suitable for a frame save
1259
     are those that are preserved across procedure calls (s0-s6). But if
1260
     a read system call is interrupted and then a dummy call is made
1261
     (see testsuite/gdb.t17/interrupt.exp) the dummy call hangs till the read
1262
     is satisfied. Then it returns with the s0-s6 registers set to the values
1263
     on entry to the read system call and our dummy frame pointer would be
1264
     destroyed. So we save the dummy frame in the proc_desc and handle the
1265
     retrieval of the frame pointer of a dummy specifically. The frame register
1266
     is set to the virtual frame (pseudo) register, it's value will always
1267
     be read as zero and will help us to catch any errors in the dummy frame
1268
     retrieval code.  */
1269
  PROC_DUMMY_FRAME (proc_desc) = sp;
1270
  PROC_FRAME_REG (proc_desc) = FP_REGNUM;
1271
  PROC_FRAME_OFFSET (proc_desc) = 0;
1272
  sp += PROC_REG_OFFSET (proc_desc);
1273
  write_register (SP_REGNUM, sp);
1274
 
1275
  PROC_LOW_ADDR (proc_desc) = CALL_DUMMY_ADDRESS ();
1276
  PROC_HIGH_ADDR (proc_desc) = PROC_LOW_ADDR (proc_desc) + 4;
1277
 
1278
  SET_PROC_DESC_IS_DUMMY (proc_desc);
1279
  PROC_PC_REG (proc_desc) = ALPHA_RA_REGNUM;
1280
}
1281
 
1282
static void
1283
alpha_pop_frame (void)
1284
{
1285
  register int regnum;
1286
  struct frame_info *frame = get_current_frame ();
1287
  CORE_ADDR new_sp = frame->frame;
1288
 
1289
  alpha_extra_func_info_t proc_desc = frame->extra_info->proc_desc;
1290
 
1291
  /* we need proc_desc to know how to restore the registers;
1292
     if it is NULL, construct (a temporary) one */
1293
  if (proc_desc == NULL)
1294
    proc_desc = find_proc_desc (frame->pc, frame->next);
1295
 
1296
  /* Question: should we copy this proc_desc and save it in
1297
     frame->proc_desc?  If we do, who will free it?
1298
     For now, we don't save a copy... */
1299
 
1300
  write_register (PC_REGNUM, FRAME_SAVED_PC (frame));
1301
  if (frame->saved_regs == NULL)
1302
    alpha_find_saved_regs (frame);
1303
  if (proc_desc)
1304
    {
1305
      for (regnum = 32; --regnum >= 0;)
1306
        if (PROC_REG_MASK (proc_desc) & (1 << regnum))
1307
          write_register (regnum,
1308
                          read_memory_integer (frame->saved_regs[regnum],
1309
                                               8));
1310
      for (regnum = 32; --regnum >= 0;)
1311
        if (PROC_FREG_MASK (proc_desc) & (1 << regnum))
1312
          write_register (regnum + FP0_REGNUM,
1313
           read_memory_integer (frame->saved_regs[regnum + FP0_REGNUM], 8));
1314
    }
1315
  write_register (SP_REGNUM, new_sp);
1316
  flush_cached_frames ();
1317
 
1318
  if (proc_desc && (PROC_DESC_IS_DUMMY (proc_desc)
1319
                    || alpha_proc_desc_is_dyn_sigtramp (proc_desc)))
1320
    {
1321
      struct linked_proc_info *pi_ptr, *prev_ptr;
1322
 
1323
      for (pi_ptr = linked_proc_desc_table, prev_ptr = NULL;
1324
           pi_ptr != NULL;
1325
           prev_ptr = pi_ptr, pi_ptr = pi_ptr->next)
1326
        {
1327
          if (&pi_ptr->info == proc_desc)
1328
            break;
1329
        }
1330
 
1331
      if (pi_ptr == NULL)
1332
        error ("Can't locate dummy extra frame info\n");
1333
 
1334
      if (prev_ptr != NULL)
1335
        prev_ptr->next = pi_ptr->next;
1336
      else
1337
        linked_proc_desc_table = pi_ptr->next;
1338
 
1339
      xfree (pi_ptr);
1340
    }
1341
}
1342
 
1343
/* To skip prologues, I use this predicate.  Returns either PC itself
1344
   if the code at PC does not look like a function prologue; otherwise
1345
   returns an address that (if we're lucky) follows the prologue.  If
1346
   LENIENT, then we must skip everything which is involved in setting
1347
   up the frame (it's OK to skip more, just so long as we don't skip
1348
   anything which might clobber the registers which are being saved.
1349
   Currently we must not skip more on the alpha, but we might need the
1350
   lenient stuff some day.  */
1351
 
1352
static CORE_ADDR
1353
alpha_skip_prologue_internal (CORE_ADDR pc, int lenient)
1354
{
1355
  unsigned long inst;
1356
  int offset;
1357
  CORE_ADDR post_prologue_pc;
1358
  char buf[4];
1359
 
1360
  /* Silently return the unaltered pc upon memory errors.
1361
     This could happen on OSF/1 if decode_line_1 tries to skip the
1362
     prologue for quickstarted shared library functions when the
1363
     shared library is not yet mapped in.
1364
     Reading target memory is slow over serial lines, so we perform
1365
     this check only if the target has shared libraries (which all
1366
     Alpha targets do).  */
1367
  if (target_read_memory (pc, buf, 4))
1368
    return pc;
1369
 
1370
  /* See if we can determine the end of the prologue via the symbol table.
1371
     If so, then return either PC, or the PC after the prologue, whichever
1372
     is greater.  */
1373
 
1374
  post_prologue_pc = after_prologue (pc, NULL);
1375
 
1376
  if (post_prologue_pc != 0)
1377
    return max (pc, post_prologue_pc);
1378
 
1379
  /* Can't determine prologue from the symbol table, need to examine
1380
     instructions.  */
1381
 
1382
  /* Skip the typical prologue instructions. These are the stack adjustment
1383
     instruction and the instructions that save registers on the stack
1384
     or in the gcc frame.  */
1385
  for (offset = 0; offset < 100; offset += 4)
1386
    {
1387
      int status;
1388
 
1389
      status = read_memory_nobpt (pc + offset, buf, 4);
1390
      if (status)
1391
        memory_error (status, pc + offset);
1392
      inst = extract_unsigned_integer (buf, 4);
1393
 
1394
      /* The alpha has no delay slots. But let's keep the lenient stuff,
1395
         we might need it for something else in the future.  */
1396
      if (lenient && 0)
1397
        continue;
1398
 
1399
      if ((inst & 0xffff0000) == 0x27bb0000)    /* ldah $gp,n($t12) */
1400
        continue;
1401
      if ((inst & 0xffff0000) == 0x23bd0000)    /* lda $gp,n($gp) */
1402
        continue;
1403
      if ((inst & 0xffff0000) == 0x23de0000)    /* lda $sp,n($sp) */
1404
        continue;
1405
      if ((inst & 0xffe01fff) == 0x43c0153e)    /* subq $sp,n,$sp */
1406
        continue;
1407
 
1408
      if ((inst & 0xfc1f0000) == 0xb41e0000
1409
          && (inst & 0xffff0000) != 0xb7fe0000)
1410
        continue;               /* stq reg,n($sp) */
1411
      /* reg != $zero */
1412
      if ((inst & 0xfc1f0000) == 0x9c1e0000
1413
          && (inst & 0xffff0000) != 0x9ffe0000)
1414
        continue;               /* stt reg,n($sp) */
1415
      /* reg != $zero */
1416
      if (inst == 0x47de040f)   /* bis sp,sp,fp */
1417
        continue;
1418
 
1419
      break;
1420
    }
1421
  return pc + offset;
1422
}
1423
 
1424
static CORE_ADDR
1425
alpha_skip_prologue (CORE_ADDR addr)
1426
{
1427
  return (alpha_skip_prologue_internal (addr, 0));
1428
}
1429
 
1430
#if 0
1431
/* Is address PC in the prologue (loosely defined) for function at
1432
   STARTADDR?  */
1433
 
1434
static int
1435
alpha_in_lenient_prologue (CORE_ADDR startaddr, CORE_ADDR pc)
1436
{
1437
  CORE_ADDR end_prologue = alpha_skip_prologue_internal (startaddr, 1);
1438
  return pc >= startaddr && pc < end_prologue;
1439
}
1440
#endif
1441
 
1442
/* The alpha needs a conversion between register and memory format if
1443
   the register is a floating point register and
1444
   memory format is float, as the register format must be double
1445
   or
1446
   memory format is an integer with 4 bytes or less, as the representation
1447
   of integers in floating point registers is different. */
1448
static void
1449
alpha_register_convert_to_virtual (int regnum, struct type *valtype,
1450
                                   char *raw_buffer, char *virtual_buffer)
1451
{
1452
  if (TYPE_LENGTH (valtype) >= REGISTER_RAW_SIZE (regnum))
1453
    {
1454
      memcpy (virtual_buffer, raw_buffer, REGISTER_VIRTUAL_SIZE (regnum));
1455
      return;
1456
    }
1457
 
1458
  if (TYPE_CODE (valtype) == TYPE_CODE_FLT)
1459
    {
1460
      double d = extract_floating (raw_buffer, REGISTER_RAW_SIZE (regnum));
1461
      store_floating (virtual_buffer, TYPE_LENGTH (valtype), d);
1462
    }
1463
  else if (TYPE_CODE (valtype) == TYPE_CODE_INT && TYPE_LENGTH (valtype) <= 4)
1464
    {
1465
      ULONGEST l;
1466
      l = extract_unsigned_integer (raw_buffer, REGISTER_RAW_SIZE (regnum));
1467
      l = ((l >> 32) & 0xc0000000) | ((l >> 29) & 0x3fffffff);
1468
      store_unsigned_integer (virtual_buffer, TYPE_LENGTH (valtype), l);
1469
    }
1470
  else
1471
    error ("Cannot retrieve value from floating point register");
1472
}
1473
 
1474
static void
1475
alpha_register_convert_to_raw (struct type *valtype, int regnum,
1476
                               char *virtual_buffer, char *raw_buffer)
1477
{
1478
  if (TYPE_LENGTH (valtype) >= REGISTER_RAW_SIZE (regnum))
1479
    {
1480
      memcpy (raw_buffer, virtual_buffer, REGISTER_RAW_SIZE (regnum));
1481
      return;
1482
    }
1483
 
1484
  if (TYPE_CODE (valtype) == TYPE_CODE_FLT)
1485
    {
1486
      double d = extract_floating (virtual_buffer, TYPE_LENGTH (valtype));
1487
      store_floating (raw_buffer, REGISTER_RAW_SIZE (regnum), d);
1488
    }
1489
  else if (TYPE_CODE (valtype) == TYPE_CODE_INT && TYPE_LENGTH (valtype) <= 4)
1490
    {
1491
      ULONGEST l;
1492
      if (TYPE_UNSIGNED (valtype))
1493
        l = extract_unsigned_integer (virtual_buffer, TYPE_LENGTH (valtype));
1494
      else
1495
        l = extract_signed_integer (virtual_buffer, TYPE_LENGTH (valtype));
1496
      l = ((l & 0xc0000000) << 32) | ((l & 0x3fffffff) << 29);
1497
      store_unsigned_integer (raw_buffer, REGISTER_RAW_SIZE (regnum), l);
1498
    }
1499
  else
1500
    error ("Cannot store value in floating point register");
1501
}
1502
 
1503
static const unsigned char *
1504
alpha_breakpoint_from_pc (CORE_ADDR *pcptr, int *lenptr)
1505
{
1506
  static const unsigned char alpha_breakpoint[] =
1507
    { 0x80, 0, 0, 0 };     /* call_pal bpt */
1508
 
1509
  *lenptr = sizeof(alpha_breakpoint);
1510
  return (alpha_breakpoint);
1511
}
1512
 
1513
/* Given a return value in `regbuf' with a type `valtype',
1514
   extract and copy its value into `valbuf'.  */
1515
 
1516
static void
1517
alpha_extract_return_value (struct type *valtype,
1518
                            char regbuf[ALPHA_REGISTER_BYTES], char *valbuf)
1519
{
1520
  if (TYPE_CODE (valtype) == TYPE_CODE_FLT)
1521
    alpha_register_convert_to_virtual (FP0_REGNUM, valtype,
1522
                                       regbuf + REGISTER_BYTE (FP0_REGNUM),
1523
                                       valbuf);
1524
  else
1525
    memcpy (valbuf, regbuf + REGISTER_BYTE (ALPHA_V0_REGNUM),
1526
            TYPE_LENGTH (valtype));
1527
}
1528
 
1529
/* Given a return value in `regbuf' with a type `valtype',
1530
   write its value into the appropriate register.  */
1531
 
1532
static void
1533
alpha_store_return_value (struct type *valtype, char *valbuf)
1534
{
1535
  char raw_buffer[ALPHA_MAX_REGISTER_RAW_SIZE];
1536
  int regnum = ALPHA_V0_REGNUM;
1537
  int length = TYPE_LENGTH (valtype);
1538
 
1539
  if (TYPE_CODE (valtype) == TYPE_CODE_FLT)
1540
    {
1541
      regnum = FP0_REGNUM;
1542
      length = REGISTER_RAW_SIZE (regnum);
1543
      alpha_register_convert_to_raw (valtype, regnum, valbuf, raw_buffer);
1544
    }
1545
  else
1546
    memcpy (raw_buffer, valbuf, length);
1547
 
1548
  write_register_bytes (REGISTER_BYTE (regnum), raw_buffer, length);
1549
}
1550
 
1551
/* Just like reinit_frame_cache, but with the right arguments to be
1552
   callable as an sfunc.  */
1553
 
1554
static void
1555
reinit_frame_cache_sfunc (char *args, int from_tty, struct cmd_list_element *c)
1556
{
1557
  reinit_frame_cache ();
1558
}
1559
 
1560
/* This is the definition of CALL_DUMMY_ADDRESS.  It's a heuristic that is used
1561
   to find a convenient place in the text segment to stick a breakpoint to
1562
   detect the completion of a target function call (ala call_function_by_hand).
1563
 */
1564
 
1565
CORE_ADDR
1566
alpha_call_dummy_address (void)
1567
{
1568
  CORE_ADDR entry;
1569
  struct minimal_symbol *sym;
1570
 
1571
  entry = entry_point_address ();
1572
 
1573
  if (entry != 0)
1574
    return entry;
1575
 
1576
  sym = lookup_minimal_symbol ("_Prelude", NULL, symfile_objfile);
1577
 
1578
  if (!sym || MSYMBOL_TYPE (sym) != mst_text)
1579
    return 0;
1580
  else
1581
    return SYMBOL_VALUE_ADDRESS (sym) + 4;
1582
}
1583
 
1584
static void
1585
alpha_fix_call_dummy (char *dummy, CORE_ADDR pc, CORE_ADDR fun, int nargs,
1586
                      struct value **args, struct type *type, int gcc_p)
1587
{
1588
  CORE_ADDR bp_address = CALL_DUMMY_ADDRESS ();
1589
 
1590
  if (bp_address == 0)
1591
    error ("no place to put call");
1592
  write_register (ALPHA_RA_REGNUM, bp_address);
1593
  write_register (ALPHA_T12_REGNUM, fun);
1594
}
1595
 
1596
/* On the Alpha, the call dummy code is nevery copied to user space
1597
   (see alpha_fix_call_dummy() above).  The contents of this do not
1598
   matter.  */
1599
LONGEST alpha_call_dummy_words[] = { 0 };
1600
 
1601
static int
1602
alpha_use_struct_convention (int gcc_p, struct type *type)
1603
{
1604
  /* Structures are returned by ref in extra arg0.  */
1605
  return 1;
1606
}
1607
 
1608
static void
1609
alpha_store_struct_return (CORE_ADDR addr, CORE_ADDR sp)
1610
{
1611
  /* Store the address of the place in which to copy the structure the
1612
     subroutine will return.  Handled by alpha_push_arguments.  */
1613
}
1614
 
1615
static CORE_ADDR
1616
alpha_extract_struct_value_address (char *regbuf)
1617
{
1618
  return (extract_address (regbuf + REGISTER_BYTE (ALPHA_V0_REGNUM),
1619
                           REGISTER_RAW_SIZE (ALPHA_V0_REGNUM)));
1620
}
1621
 
1622
/* Figure out where the longjmp will land.
1623
   We expect the first arg to be a pointer to the jmp_buf structure from
1624
   which we extract the PC (JB_PC) that we will land at.  The PC is copied
1625
   into the "pc".  This routine returns true on success.  */
1626
 
1627
static int
1628
alpha_get_longjmp_target (CORE_ADDR *pc)
1629
{
1630
  struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
1631
  CORE_ADDR jb_addr;
1632
  char raw_buffer[ALPHA_MAX_REGISTER_RAW_SIZE];
1633
 
1634
  jb_addr = read_register (ALPHA_A0_REGNUM);
1635
 
1636
  if (target_read_memory (jb_addr + (tdep->jb_pc * tdep->jb_elt_size),
1637
                          raw_buffer, tdep->jb_elt_size))
1638
    return 0;
1639
 
1640
  *pc = extract_address (raw_buffer, tdep->jb_elt_size);
1641
  return 1;
1642
}
1643
 
1644
/* alpha_software_single_step() is called just before we want to resume
1645
   the inferior, if we want to single-step it but there is no hardware
1646
   or kernel single-step support (NetBSD on Alpha, for example).  We find
1647
   the target of the coming instruction and breakpoint it.
1648
 
1649
   single_step is also called just after the inferior stops.  If we had
1650
   set up a simulated single-step, we undo our damage.  */
1651
 
1652
static CORE_ADDR
1653
alpha_next_pc (CORE_ADDR pc)
1654
{
1655
  unsigned int insn;
1656
  unsigned int op;
1657
  int offset;
1658
  LONGEST rav;
1659
 
1660
  insn = read_memory_unsigned_integer (pc, sizeof (insn));
1661
 
1662
  /* Opcode is top 6 bits. */
1663
  op = (insn >> 26) & 0x3f;
1664
 
1665
  if (op == 0x1a)
1666
    {
1667
      /* Jump format: target PC is:
1668
         RB & ~3  */
1669
      return (read_register ((insn >> 16) & 0x1f) & ~3);
1670
    }
1671
 
1672
  if ((op & 0x30) == 0x30)
1673
    {
1674
      /* Branch format: target PC is:
1675
         (new PC) + (4 * sext(displacement))  */
1676
      if (op == 0x30 ||         /* BR */
1677
          op == 0x34)           /* BSR */
1678
        {
1679
 branch_taken:
1680
          offset = (insn & 0x001fffff);
1681
          if (offset & 0x00100000)
1682
            offset  |= 0xffe00000;
1683
          offset *= 4;
1684
          return (pc + 4 + offset);
1685
        }
1686
 
1687
      /* Need to determine if branch is taken; read RA.  */
1688
      rav = (LONGEST) read_register ((insn >> 21) & 0x1f);
1689
      switch (op)
1690
        {
1691
        case 0x38:              /* BLBC */
1692
          if ((rav & 1) == 0)
1693
            goto branch_taken;
1694
          break;
1695
        case 0x3c:              /* BLBS */
1696
          if (rav & 1)
1697
            goto branch_taken;
1698
          break;
1699
        case 0x39:              /* BEQ */
1700
          if (rav == 0)
1701
            goto branch_taken;
1702
          break;
1703
        case 0x3d:              /* BNE */
1704
          if (rav != 0)
1705
            goto branch_taken;
1706
          break;
1707
        case 0x3a:              /* BLT */
1708
          if (rav < 0)
1709
            goto branch_taken;
1710
          break;
1711
        case 0x3b:              /* BLE */
1712
          if (rav <= 0)
1713
            goto branch_taken;
1714
          break;
1715
        case 0x3f:              /* BGT */
1716
          if (rav > 0)
1717
            goto branch_taken;
1718
          break;
1719
        case 0x3e:              /* BGE */
1720
          if (rav >= 0)
1721
            goto branch_taken;
1722
          break;
1723
        }
1724
    }
1725
 
1726
  /* Not a branch or branch not taken; target PC is:
1727
     pc + 4  */
1728
  return (pc + 4);
1729
}
1730
 
1731
void
1732
alpha_software_single_step (enum target_signal sig, int insert_breakpoints_p)
1733
{
1734
  static CORE_ADDR next_pc;
1735
  typedef char binsn_quantum[BREAKPOINT_MAX];
1736
  static binsn_quantum break_mem;
1737
  CORE_ADDR pc;
1738
 
1739
  if (insert_breakpoints_p)
1740
    {
1741
      pc = read_pc ();
1742
      next_pc = alpha_next_pc (pc);
1743
 
1744
      target_insert_breakpoint (next_pc, break_mem);
1745
    }
1746
  else
1747
    {
1748
      target_remove_breakpoint (next_pc, break_mem);
1749
      write_pc (next_pc);
1750
    }
1751
}
1752
 
1753
 
1754
 
1755
/* Initialize the current architecture based on INFO.  If possible, re-use an
1756
   architecture from ARCHES, which is a list of architectures already created
1757
   during this debugging session.
1758
 
1759
   Called e.g. at program startup, when reading a core file, and when reading
1760
   a binary file.  */
1761
 
1762
static struct gdbarch *
1763
alpha_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
1764
{
1765
  struct gdbarch_tdep *tdep;
1766
  struct gdbarch *gdbarch;
1767
  enum gdb_osabi osabi = GDB_OSABI_UNKNOWN;
1768
 
1769
  /* Try to determine the ABI of the object we are loading.  */
1770
 
1771
  if (info.abfd != NULL)
1772
    {
1773
      osabi = gdbarch_lookup_osabi (info.abfd);
1774
      if (osabi == GDB_OSABI_UNKNOWN)
1775
        {
1776
          /* If it's an ECOFF file, assume it's OSF/1.  */
1777
          if (bfd_get_flavour (info.abfd) == bfd_target_ecoff_flavour)
1778
            osabi = GDB_OSABI_OSF1;
1779
        }
1780
    }
1781
 
1782
  /* Find a candidate among extant architectures.  */
1783
  for (arches = gdbarch_list_lookup_by_info (arches, &info);
1784
       arches != NULL;
1785
       arches = gdbarch_list_lookup_by_info (arches->next, &info))
1786
    {
1787
      /* Make sure the ABI selection matches.  */
1788
      tdep = gdbarch_tdep (arches->gdbarch);
1789
      if (tdep && tdep->osabi == osabi)
1790
        return arches->gdbarch;
1791
    }
1792
 
1793
  tdep = xmalloc (sizeof (struct gdbarch_tdep));
1794
  gdbarch = gdbarch_alloc (&info, tdep);
1795
 
1796
  tdep->osabi = osabi;
1797
 
1798
  /* Lowest text address.  This is used by heuristic_proc_start() to
1799
     decide when to stop looking.  */
1800
  tdep->vm_min_address = (CORE_ADDR) 0x120000000;
1801
 
1802
  tdep->dynamic_sigtramp_offset = NULL;
1803
  tdep->skip_sigtramp_frame = NULL;
1804
  tdep->sigcontext_addr = NULL;
1805
 
1806
  tdep->jb_pc = -1;     /* longjmp support not enabled by default  */
1807
 
1808
  /* Type sizes */
1809
  set_gdbarch_short_bit (gdbarch, 16);
1810
  set_gdbarch_int_bit (gdbarch, 32);
1811
  set_gdbarch_long_bit (gdbarch, 64);
1812
  set_gdbarch_long_long_bit (gdbarch, 64);
1813
  set_gdbarch_float_bit (gdbarch, 32);
1814
  set_gdbarch_double_bit (gdbarch, 64);
1815
  set_gdbarch_long_double_bit (gdbarch, 64);
1816
  set_gdbarch_ptr_bit (gdbarch, 64);
1817
 
1818
  /* Register info */
1819
  set_gdbarch_num_regs (gdbarch, ALPHA_NUM_REGS);
1820
  set_gdbarch_sp_regnum (gdbarch, ALPHA_SP_REGNUM);
1821
  set_gdbarch_fp_regnum (gdbarch, ALPHA_FP_REGNUM);
1822
  set_gdbarch_pc_regnum (gdbarch, ALPHA_PC_REGNUM);
1823
  set_gdbarch_fp0_regnum (gdbarch, ALPHA_FP0_REGNUM);
1824
 
1825
  set_gdbarch_register_name (gdbarch, alpha_register_name);
1826
  set_gdbarch_register_size (gdbarch, ALPHA_REGISTER_SIZE);
1827
  set_gdbarch_register_bytes (gdbarch, ALPHA_REGISTER_BYTES);
1828
  set_gdbarch_register_byte (gdbarch, alpha_register_byte);
1829
  set_gdbarch_register_raw_size (gdbarch, alpha_register_raw_size);
1830
  set_gdbarch_max_register_raw_size (gdbarch, ALPHA_MAX_REGISTER_RAW_SIZE);
1831
  set_gdbarch_register_virtual_size (gdbarch, alpha_register_virtual_size);
1832
  set_gdbarch_max_register_virtual_size (gdbarch,
1833
                                         ALPHA_MAX_REGISTER_VIRTUAL_SIZE);
1834
  set_gdbarch_register_virtual_type (gdbarch, alpha_register_virtual_type);
1835
 
1836
  set_gdbarch_cannot_fetch_register (gdbarch, alpha_cannot_fetch_register);
1837
  set_gdbarch_cannot_store_register (gdbarch, alpha_cannot_store_register);
1838
 
1839
  set_gdbarch_register_convertible (gdbarch, alpha_register_convertible);
1840
  set_gdbarch_register_convert_to_virtual (gdbarch,
1841
                                           alpha_register_convert_to_virtual);
1842
  set_gdbarch_register_convert_to_raw (gdbarch, alpha_register_convert_to_raw);
1843
 
1844
  set_gdbarch_skip_prologue (gdbarch, alpha_skip_prologue);
1845
 
1846
  set_gdbarch_frame_num_args (gdbarch, frame_num_args_unknown);
1847
  set_gdbarch_frameless_function_invocation (gdbarch,
1848
                                    generic_frameless_function_invocation_not);
1849
 
1850
  set_gdbarch_saved_pc_after_call (gdbarch, alpha_saved_pc_after_call);
1851
 
1852
  set_gdbarch_frame_chain (gdbarch, alpha_frame_chain);
1853
  set_gdbarch_frame_chain_valid (gdbarch, func_frame_chain_valid);
1854
  set_gdbarch_frame_saved_pc (gdbarch, alpha_frame_saved_pc);
1855
 
1856
  set_gdbarch_frame_init_saved_regs (gdbarch, alpha_frame_init_saved_regs);
1857
 
1858
  set_gdbarch_use_struct_convention (gdbarch, alpha_use_struct_convention);
1859
  set_gdbarch_deprecated_extract_return_value (gdbarch, alpha_extract_return_value);
1860
 
1861
  set_gdbarch_store_struct_return (gdbarch, alpha_store_struct_return);
1862
  set_gdbarch_deprecated_store_return_value (gdbarch, alpha_store_return_value);
1863
  set_gdbarch_deprecated_extract_struct_value_address (gdbarch,
1864
                                            alpha_extract_struct_value_address);
1865
 
1866
  /* Settings for calling functions in the inferior.  */
1867
  set_gdbarch_use_generic_dummy_frames (gdbarch, 0);
1868
  set_gdbarch_call_dummy_length (gdbarch, 0);
1869
  set_gdbarch_push_arguments (gdbarch, alpha_push_arguments);
1870
  set_gdbarch_pop_frame (gdbarch, alpha_pop_frame);
1871
 
1872
  /* On the Alpha, the call dummy code is never copied to user space,
1873
     stopping the user call is achieved via a bp_call_dummy breakpoint.
1874
     But we need a fake CALL_DUMMY definition to enable the proper
1875
     call_function_by_hand and to avoid zero length array warnings.  */
1876
  set_gdbarch_call_dummy_p (gdbarch, 1);
1877
  set_gdbarch_call_dummy_words (gdbarch, alpha_call_dummy_words);
1878
  set_gdbarch_sizeof_call_dummy_words (gdbarch, 0);
1879
  set_gdbarch_frame_args_address (gdbarch, alpha_frame_args_address);
1880
  set_gdbarch_frame_locals_address (gdbarch, alpha_frame_locals_address);
1881
  set_gdbarch_init_extra_frame_info (gdbarch, alpha_init_extra_frame_info);
1882
 
1883
  /* Alpha OSF/1 inhibits execution of code on the stack.  But there is
1884
     no need for a dummy on the Alpha.  PUSH_ARGUMENTS takes care of all
1885
     argument handling and bp_call_dummy takes care of stopping the dummy.  */
1886
  set_gdbarch_call_dummy_location (gdbarch, AT_ENTRY_POINT);
1887
  set_gdbarch_call_dummy_address (gdbarch, alpha_call_dummy_address);
1888
  set_gdbarch_call_dummy_breakpoint_offset_p (gdbarch, 1);
1889
  set_gdbarch_call_dummy_breakpoint_offset (gdbarch, 0);
1890
  set_gdbarch_call_dummy_start_offset (gdbarch, 0);
1891
  set_gdbarch_pc_in_call_dummy (gdbarch, pc_in_call_dummy_at_entry_point);
1892
  set_gdbarch_call_dummy_stack_adjust_p (gdbarch, 0);
1893
  set_gdbarch_push_dummy_frame (gdbarch, alpha_push_dummy_frame);
1894
  set_gdbarch_fix_call_dummy (gdbarch, alpha_fix_call_dummy);
1895
  set_gdbarch_init_frame_pc (gdbarch, init_frame_pc_noop);
1896
  set_gdbarch_init_frame_pc_first (gdbarch, alpha_init_frame_pc_first);
1897
 
1898
  set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
1899
  set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
1900
 
1901
  /* Floats are always passed as doubles.  */
1902
  set_gdbarch_coerce_float_to_double (gdbarch,
1903
                                      standard_coerce_float_to_double);
1904
 
1905
  set_gdbarch_breakpoint_from_pc (gdbarch, alpha_breakpoint_from_pc);
1906
  set_gdbarch_decr_pc_after_break (gdbarch, 4);
1907
 
1908
  set_gdbarch_function_start_offset (gdbarch, 0);
1909
  set_gdbarch_frame_args_skip (gdbarch, 0);
1910
 
1911
  /* Hook in ABI-specific overrides, if they have been registered.  */
1912
  gdbarch_init_osabi (info, gdbarch, osabi);
1913
 
1914
  /* Now that we have tuned the configuration, set a few final things
1915
     based on what the OS ABI has told us.  */
1916
 
1917
  if (tdep->jb_pc >= 0)
1918
    set_gdbarch_get_longjmp_target (gdbarch, alpha_get_longjmp_target);
1919
 
1920
  return gdbarch;
1921
}
1922
 
1923
static void
1924
alpha_dump_tdep (struct gdbarch *current_gdbarch, struct ui_file *file)
1925
{
1926
  struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
1927
 
1928
  if (tdep == NULL)
1929
    return;
1930
 
1931
  fprintf_unfiltered (file, "alpha_dump_tdep: OS ABI = %s\n",
1932
                      gdbarch_osabi_name (tdep->osabi));
1933
 
1934
  fprintf_unfiltered (file,
1935
                      "alpha_dump_tdep: vm_min_address = 0x%lx\n",
1936
                      (long) tdep->vm_min_address);
1937
 
1938
  fprintf_unfiltered (file,
1939
                      "alpha_dump_tdep: jb_pc = %d\n",
1940
                      tdep->jb_pc);
1941
  fprintf_unfiltered (file,
1942
                      "alpha_dump_tdep: jb_elt_size = %ld\n",
1943
                      (long) tdep->jb_elt_size);
1944
}
1945
 
1946
void
1947
_initialize_alpha_tdep (void)
1948
{
1949
  struct cmd_list_element *c;
1950
 
1951
  gdbarch_register (bfd_arch_alpha, alpha_gdbarch_init, alpha_dump_tdep);
1952
 
1953
  tm_print_insn = print_insn_alpha;
1954
 
1955
  /* Let the user set the fence post for heuristic_proc_start.  */
1956
 
1957
  /* We really would like to have both "0" and "unlimited" work, but
1958
     command.c doesn't deal with that.  So make it a var_zinteger
1959
     because the user can always use "999999" or some such for unlimited.  */
1960
  c = add_set_cmd ("heuristic-fence-post", class_support, var_zinteger,
1961
                   (char *) &heuristic_fence_post,
1962
                   "\
1963
Set the distance searched for the start of a function.\n\
1964
If you are debugging a stripped executable, GDB needs to search through the\n\
1965
program for the start of a function.  This command sets the distance of the\n\
1966
search.  The only need to set it is when debugging a stripped executable.",
1967
                   &setlist);
1968
  /* We need to throw away the frame cache when we set this, since it
1969
     might change our ability to get backtraces.  */
1970
  set_cmd_sfunc (c, reinit_frame_cache_sfunc);
1971
  add_show_from_set (c, &showlist);
1972
}

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