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[deliverable/binutils-gdb.git] / gdb / lm32-tdep.c
1 /* Target-dependent code for Lattice Mico32 processor, for GDB.
2 Contributed by Jon Beniston <jon@beniston.com>
3
4 Copyright (C) 2009-2015 Free Software Foundation, Inc.
5
6 This file is part of GDB.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20
21 #include "defs.h"
22 #include "frame.h"
23 #include "frame-unwind.h"
24 #include "frame-base.h"
25 #include "inferior.h"
26 #include "dis-asm.h"
27 #include "symfile.h"
28 #include "remote.h"
29 #include "gdbcore.h"
30 #include "gdb/sim-lm32.h"
31 #include "gdb/callback.h"
32 #include "gdb/remote-sim.h"
33 #include "sim-regno.h"
34 #include "arch-utils.h"
35 #include "regcache.h"
36 #include "trad-frame.h"
37 #include "reggroups.h"
38 #include "opcodes/lm32-desc.h"
39
40 /* Macros to extract fields from an instruction. */
41 #define LM32_OPCODE(insn) ((insn >> 26) & 0x3f)
42 #define LM32_REG0(insn) ((insn >> 21) & 0x1f)
43 #define LM32_REG1(insn) ((insn >> 16) & 0x1f)
44 #define LM32_REG2(insn) ((insn >> 11) & 0x1f)
45 #define LM32_IMM16(insn) ((((long)insn & 0xffff) << 16) >> 16)
46
47 struct gdbarch_tdep
48 {
49 /* gdbarch target dependent data here. Currently unused for LM32. */
50 };
51
52 struct lm32_frame_cache
53 {
54 /* The frame's base. Used when constructing a frame ID. */
55 CORE_ADDR base;
56 CORE_ADDR pc;
57 /* Size of frame. */
58 int size;
59 /* Table indicating the location of each and every register. */
60 struct trad_frame_saved_reg *saved_regs;
61 };
62
63 /* Add the available register groups. */
64
65 static void
66 lm32_add_reggroups (struct gdbarch *gdbarch)
67 {
68 reggroup_add (gdbarch, general_reggroup);
69 reggroup_add (gdbarch, all_reggroup);
70 reggroup_add (gdbarch, system_reggroup);
71 }
72
73 /* Return whether a given register is in a given group. */
74
75 static int
76 lm32_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
77 struct reggroup *group)
78 {
79 if (group == general_reggroup)
80 return ((regnum >= SIM_LM32_R0_REGNUM) && (regnum <= SIM_LM32_RA_REGNUM))
81 || (regnum == SIM_LM32_PC_REGNUM);
82 else if (group == system_reggroup)
83 return ((regnum >= SIM_LM32_EA_REGNUM) && (regnum <= SIM_LM32_BA_REGNUM))
84 || ((regnum >= SIM_LM32_EID_REGNUM) && (regnum <= SIM_LM32_IP_REGNUM));
85 return default_register_reggroup_p (gdbarch, regnum, group);
86 }
87
88 /* Return a name that corresponds to the given register number. */
89
90 static const char *
91 lm32_register_name (struct gdbarch *gdbarch, int reg_nr)
92 {
93 static char *register_names[] = {
94 "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
95 "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
96 "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
97 "r24", "r25", "gp", "fp", "sp", "ra", "ea", "ba",
98 "PC", "EID", "EBA", "DEBA", "IE", "IM", "IP"
99 };
100
101 if ((reg_nr < 0) || (reg_nr >= ARRAY_SIZE (register_names)))
102 return NULL;
103 else
104 return register_names[reg_nr];
105 }
106
107 /* Return type of register. */
108
109 static struct type *
110 lm32_register_type (struct gdbarch *gdbarch, int reg_nr)
111 {
112 return builtin_type (gdbarch)->builtin_int32;
113 }
114
115 /* Return non-zero if a register can't be written. */
116
117 static int
118 lm32_cannot_store_register (struct gdbarch *gdbarch, int regno)
119 {
120 return (regno == SIM_LM32_R0_REGNUM) || (regno == SIM_LM32_EID_REGNUM);
121 }
122
123 /* Analyze a function's prologue. */
124
125 static CORE_ADDR
126 lm32_analyze_prologue (struct gdbarch *gdbarch,
127 CORE_ADDR pc, CORE_ADDR limit,
128 struct lm32_frame_cache *info)
129 {
130 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
131 unsigned long instruction;
132
133 /* Keep reading though instructions, until we come across an instruction
134 that isn't likely to be part of the prologue. */
135 info->size = 0;
136 for (; pc < limit; pc += 4)
137 {
138
139 /* Read an instruction. */
140 instruction = read_memory_integer (pc, 4, byte_order);
141
142 if ((LM32_OPCODE (instruction) == OP_SW)
143 && (LM32_REG0 (instruction) == SIM_LM32_SP_REGNUM))
144 {
145 /* Any stack displaced store is likely part of the prologue.
146 Record that the register is being saved, and the offset
147 into the stack. */
148 info->saved_regs[LM32_REG1 (instruction)].addr =
149 LM32_IMM16 (instruction);
150 }
151 else if ((LM32_OPCODE (instruction) == OP_ADDI)
152 && (LM32_REG1 (instruction) == SIM_LM32_SP_REGNUM))
153 {
154 /* An add to the SP is likely to be part of the prologue.
155 Adjust stack size by whatever the instruction adds to the sp. */
156 info->size -= LM32_IMM16 (instruction);
157 }
158 else if ( /* add fp,fp,sp */
159 ((LM32_OPCODE (instruction) == OP_ADD)
160 && (LM32_REG2 (instruction) == SIM_LM32_FP_REGNUM)
161 && (LM32_REG0 (instruction) == SIM_LM32_FP_REGNUM)
162 && (LM32_REG1 (instruction) == SIM_LM32_SP_REGNUM))
163 /* mv fp,imm */
164 || ((LM32_OPCODE (instruction) == OP_ADDI)
165 && (LM32_REG1 (instruction) == SIM_LM32_FP_REGNUM)
166 && (LM32_REG0 (instruction) == SIM_LM32_R0_REGNUM)))
167 {
168 /* Likely to be in the prologue for functions that require
169 a frame pointer. */
170 }
171 else
172 {
173 /* Any other instruction is likely not to be part of the
174 prologue. */
175 break;
176 }
177 }
178
179 return pc;
180 }
181
182 /* Return PC of first non prologue instruction, for the function at the
183 specified address. */
184
185 static CORE_ADDR
186 lm32_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
187 {
188 CORE_ADDR func_addr, limit_pc;
189 struct lm32_frame_cache frame_info;
190 struct trad_frame_saved_reg saved_regs[SIM_LM32_NUM_REGS];
191
192 /* See if we can determine the end of the prologue via the symbol table.
193 If so, then return either PC, or the PC after the prologue, whichever
194 is greater. */
195 if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
196 {
197 CORE_ADDR post_prologue_pc
198 = skip_prologue_using_sal (gdbarch, func_addr);
199 if (post_prologue_pc != 0)
200 return max (pc, post_prologue_pc);
201 }
202
203 /* Can't determine prologue from the symbol table, need to examine
204 instructions. */
205
206 /* Find an upper limit on the function prologue using the debug
207 information. If the debug information could not be used to provide
208 that bound, then use an arbitrary large number as the upper bound. */
209 limit_pc = skip_prologue_using_sal (gdbarch, pc);
210 if (limit_pc == 0)
211 limit_pc = pc + 100; /* Magic. */
212
213 frame_info.saved_regs = saved_regs;
214 return lm32_analyze_prologue (gdbarch, pc, limit_pc, &frame_info);
215 }
216
217 /* Create a breakpoint instruction. */
218
219 static const gdb_byte *
220 lm32_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr,
221 int *lenptr)
222 {
223 static const gdb_byte breakpoint[4] = { OP_RAISE << 2, 0, 0, 2 };
224
225 *lenptr = sizeof (breakpoint);
226 return breakpoint;
227 }
228
229 /* Setup registers and stack for faking a call to a function in the
230 inferior. */
231
232 static CORE_ADDR
233 lm32_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
234 struct regcache *regcache, CORE_ADDR bp_addr,
235 int nargs, struct value **args, CORE_ADDR sp,
236 int struct_return, CORE_ADDR struct_addr)
237 {
238 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
239 int first_arg_reg = SIM_LM32_R1_REGNUM;
240 int num_arg_regs = 8;
241 int i;
242
243 /* Set the return address. */
244 regcache_cooked_write_signed (regcache, SIM_LM32_RA_REGNUM, bp_addr);
245
246 /* If we're returning a large struct, a pointer to the address to
247 store it at is passed as a first hidden parameter. */
248 if (struct_return)
249 {
250 regcache_cooked_write_unsigned (regcache, first_arg_reg, struct_addr);
251 first_arg_reg++;
252 num_arg_regs--;
253 sp -= 4;
254 }
255
256 /* Setup parameters. */
257 for (i = 0; i < nargs; i++)
258 {
259 struct value *arg = args[i];
260 struct type *arg_type = check_typedef (value_type (arg));
261 gdb_byte *contents;
262 ULONGEST val;
263
264 /* Promote small integer types to int. */
265 switch (TYPE_CODE (arg_type))
266 {
267 case TYPE_CODE_INT:
268 case TYPE_CODE_BOOL:
269 case TYPE_CODE_CHAR:
270 case TYPE_CODE_RANGE:
271 case TYPE_CODE_ENUM:
272 if (TYPE_LENGTH (arg_type) < 4)
273 {
274 arg_type = builtin_type (gdbarch)->builtin_int32;
275 arg = value_cast (arg_type, arg);
276 }
277 break;
278 }
279
280 /* FIXME: Handle structures. */
281
282 contents = (gdb_byte *) value_contents (arg);
283 val = extract_unsigned_integer (contents, TYPE_LENGTH (arg_type),
284 byte_order);
285
286 /* First num_arg_regs parameters are passed by registers,
287 and the rest are passed on the stack. */
288 if (i < num_arg_regs)
289 regcache_cooked_write_unsigned (regcache, first_arg_reg + i, val);
290 else
291 {
292 write_memory (sp, (void *) &val, TYPE_LENGTH (arg_type));
293 sp -= 4;
294 }
295 }
296
297 /* Update stack pointer. */
298 regcache_cooked_write_signed (regcache, SIM_LM32_SP_REGNUM, sp);
299
300 /* Return adjusted stack pointer. */
301 return sp;
302 }
303
304 /* Extract return value after calling a function in the inferior. */
305
306 static void
307 lm32_extract_return_value (struct type *type, struct regcache *regcache,
308 gdb_byte *valbuf)
309 {
310 struct gdbarch *gdbarch = get_regcache_arch (regcache);
311 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
312 ULONGEST l;
313 CORE_ADDR return_buffer;
314
315 if (TYPE_CODE (type) != TYPE_CODE_STRUCT
316 && TYPE_CODE (type) != TYPE_CODE_UNION
317 && TYPE_CODE (type) != TYPE_CODE_ARRAY && TYPE_LENGTH (type) <= 4)
318 {
319 /* Return value is returned in a single register. */
320 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
321 store_unsigned_integer (valbuf, TYPE_LENGTH (type), byte_order, l);
322 }
323 else if ((TYPE_CODE (type) == TYPE_CODE_INT) && (TYPE_LENGTH (type) == 8))
324 {
325 /* 64-bit values are returned in a register pair. */
326 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
327 memcpy (valbuf, &l, 4);
328 regcache_cooked_read_unsigned (regcache, SIM_LM32_R2_REGNUM, &l);
329 memcpy (valbuf + 4, &l, 4);
330 }
331 else
332 {
333 /* Aggregate types greater than a single register are returned
334 in memory. FIXME: Unless they are only 2 regs?. */
335 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
336 return_buffer = l;
337 read_memory (return_buffer, valbuf, TYPE_LENGTH (type));
338 }
339 }
340
341 /* Write into appropriate registers a function return value of type
342 TYPE, given in virtual format. */
343 static void
344 lm32_store_return_value (struct type *type, struct regcache *regcache,
345 const gdb_byte *valbuf)
346 {
347 struct gdbarch *gdbarch = get_regcache_arch (regcache);
348 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
349 ULONGEST val;
350 int len = TYPE_LENGTH (type);
351
352 if (len <= 4)
353 {
354 val = extract_unsigned_integer (valbuf, len, byte_order);
355 regcache_cooked_write_unsigned (regcache, SIM_LM32_R1_REGNUM, val);
356 }
357 else if (len <= 8)
358 {
359 val = extract_unsigned_integer (valbuf, 4, byte_order);
360 regcache_cooked_write_unsigned (regcache, SIM_LM32_R1_REGNUM, val);
361 val = extract_unsigned_integer (valbuf + 4, len - 4, byte_order);
362 regcache_cooked_write_unsigned (regcache, SIM_LM32_R2_REGNUM, val);
363 }
364 else
365 error (_("lm32_store_return_value: type length too large."));
366 }
367
368 /* Determine whether a functions return value is in a register or memory. */
369 static enum return_value_convention
370 lm32_return_value (struct gdbarch *gdbarch, struct value *function,
371 struct type *valtype, struct regcache *regcache,
372 gdb_byte *readbuf, const gdb_byte *writebuf)
373 {
374 enum type_code code = TYPE_CODE (valtype);
375
376 if (code == TYPE_CODE_STRUCT
377 || code == TYPE_CODE_UNION
378 || code == TYPE_CODE_ARRAY || TYPE_LENGTH (valtype) > 8)
379 return RETURN_VALUE_STRUCT_CONVENTION;
380
381 if (readbuf)
382 lm32_extract_return_value (valtype, regcache, readbuf);
383 if (writebuf)
384 lm32_store_return_value (valtype, regcache, writebuf);
385
386 return RETURN_VALUE_REGISTER_CONVENTION;
387 }
388
389 static CORE_ADDR
390 lm32_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
391 {
392 return frame_unwind_register_unsigned (next_frame, SIM_LM32_PC_REGNUM);
393 }
394
395 static CORE_ADDR
396 lm32_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
397 {
398 return frame_unwind_register_unsigned (next_frame, SIM_LM32_SP_REGNUM);
399 }
400
401 static struct frame_id
402 lm32_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
403 {
404 CORE_ADDR sp = get_frame_register_unsigned (this_frame, SIM_LM32_SP_REGNUM);
405
406 return frame_id_build (sp, get_frame_pc (this_frame));
407 }
408
409 /* Put here the code to store, into fi->saved_regs, the addresses of
410 the saved registers of frame described by FRAME_INFO. This
411 includes special registers such as pc and fp saved in special ways
412 in the stack frame. sp is even more special: the address we return
413 for it IS the sp for the next frame. */
414
415 static struct lm32_frame_cache *
416 lm32_frame_cache (struct frame_info *this_frame, void **this_prologue_cache)
417 {
418 CORE_ADDR current_pc;
419 ULONGEST prev_sp;
420 ULONGEST this_base;
421 struct lm32_frame_cache *info;
422 int i;
423
424 if ((*this_prologue_cache))
425 return (*this_prologue_cache);
426
427 info = FRAME_OBSTACK_ZALLOC (struct lm32_frame_cache);
428 (*this_prologue_cache) = info;
429 info->saved_regs = trad_frame_alloc_saved_regs (this_frame);
430
431 info->pc = get_frame_func (this_frame);
432 current_pc = get_frame_pc (this_frame);
433 lm32_analyze_prologue (get_frame_arch (this_frame),
434 info->pc, current_pc, info);
435
436 /* Compute the frame's base, and the previous frame's SP. */
437 this_base = get_frame_register_unsigned (this_frame, SIM_LM32_SP_REGNUM);
438 prev_sp = this_base + info->size;
439 info->base = this_base;
440
441 /* Convert callee save offsets into addresses. */
442 for (i = 0; i < gdbarch_num_regs (get_frame_arch (this_frame)) - 1; i++)
443 {
444 if (trad_frame_addr_p (info->saved_regs, i))
445 info->saved_regs[i].addr = this_base + info->saved_regs[i].addr;
446 }
447
448 /* The call instruction moves the caller's PC in the callee's RA register.
449 Since this is an unwind, do the reverse. Copy the location of RA register
450 into PC (the address / regnum) so that a request for PC will be
451 converted into a request for the RA register. */
452 info->saved_regs[SIM_LM32_PC_REGNUM] = info->saved_regs[SIM_LM32_RA_REGNUM];
453
454 /* The previous frame's SP needed to be computed. Save the computed
455 value. */
456 trad_frame_set_value (info->saved_regs, SIM_LM32_SP_REGNUM, prev_sp);
457
458 return info;
459 }
460
461 static void
462 lm32_frame_this_id (struct frame_info *this_frame, void **this_cache,
463 struct frame_id *this_id)
464 {
465 struct lm32_frame_cache *cache = lm32_frame_cache (this_frame, this_cache);
466
467 /* This marks the outermost frame. */
468 if (cache->base == 0)
469 return;
470
471 (*this_id) = frame_id_build (cache->base, cache->pc);
472 }
473
474 static struct value *
475 lm32_frame_prev_register (struct frame_info *this_frame,
476 void **this_prologue_cache, int regnum)
477 {
478 struct lm32_frame_cache *info;
479
480 info = lm32_frame_cache (this_frame, this_prologue_cache);
481 return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
482 }
483
484 static const struct frame_unwind lm32_frame_unwind = {
485 NORMAL_FRAME,
486 default_frame_unwind_stop_reason,
487 lm32_frame_this_id,
488 lm32_frame_prev_register,
489 NULL,
490 default_frame_sniffer
491 };
492
493 static CORE_ADDR
494 lm32_frame_base_address (struct frame_info *this_frame, void **this_cache)
495 {
496 struct lm32_frame_cache *info = lm32_frame_cache (this_frame, this_cache);
497
498 return info->base;
499 }
500
501 static const struct frame_base lm32_frame_base = {
502 &lm32_frame_unwind,
503 lm32_frame_base_address,
504 lm32_frame_base_address,
505 lm32_frame_base_address
506 };
507
508 static CORE_ADDR
509 lm32_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
510 {
511 /* Align to the size of an instruction (so that they can safely be
512 pushed onto the stack. */
513 return sp & ~3;
514 }
515
516 static struct gdbarch *
517 lm32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
518 {
519 struct gdbarch *gdbarch;
520 struct gdbarch_tdep *tdep;
521
522 /* If there is already a candidate, use it. */
523 arches = gdbarch_list_lookup_by_info (arches, &info);
524 if (arches != NULL)
525 return arches->gdbarch;
526
527 /* None found, create a new architecture from the information provided. */
528 tdep = XNEW (struct gdbarch_tdep);
529 gdbarch = gdbarch_alloc (&info, tdep);
530
531 /* Type sizes. */
532 set_gdbarch_short_bit (gdbarch, 16);
533 set_gdbarch_int_bit (gdbarch, 32);
534 set_gdbarch_long_bit (gdbarch, 32);
535 set_gdbarch_long_long_bit (gdbarch, 64);
536 set_gdbarch_float_bit (gdbarch, 32);
537 set_gdbarch_double_bit (gdbarch, 64);
538 set_gdbarch_long_double_bit (gdbarch, 64);
539 set_gdbarch_ptr_bit (gdbarch, 32);
540
541 /* Register info. */
542 set_gdbarch_num_regs (gdbarch, SIM_LM32_NUM_REGS);
543 set_gdbarch_sp_regnum (gdbarch, SIM_LM32_SP_REGNUM);
544 set_gdbarch_pc_regnum (gdbarch, SIM_LM32_PC_REGNUM);
545 set_gdbarch_register_name (gdbarch, lm32_register_name);
546 set_gdbarch_register_type (gdbarch, lm32_register_type);
547 set_gdbarch_cannot_store_register (gdbarch, lm32_cannot_store_register);
548
549 /* Frame info. */
550 set_gdbarch_skip_prologue (gdbarch, lm32_skip_prologue);
551 set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
552 set_gdbarch_decr_pc_after_break (gdbarch, 0);
553 set_gdbarch_frame_args_skip (gdbarch, 0);
554
555 /* Frame unwinding. */
556 set_gdbarch_frame_align (gdbarch, lm32_frame_align);
557 frame_base_set_default (gdbarch, &lm32_frame_base);
558 set_gdbarch_unwind_pc (gdbarch, lm32_unwind_pc);
559 set_gdbarch_unwind_sp (gdbarch, lm32_unwind_sp);
560 set_gdbarch_dummy_id (gdbarch, lm32_dummy_id);
561 frame_unwind_append_unwinder (gdbarch, &lm32_frame_unwind);
562
563 /* Breakpoints. */
564 set_gdbarch_breakpoint_from_pc (gdbarch, lm32_breakpoint_from_pc);
565 set_gdbarch_have_nonsteppable_watchpoint (gdbarch, 1);
566
567 /* Calling functions in the inferior. */
568 set_gdbarch_push_dummy_call (gdbarch, lm32_push_dummy_call);
569 set_gdbarch_return_value (gdbarch, lm32_return_value);
570
571 /* Instruction disassembler. */
572 set_gdbarch_print_insn (gdbarch, print_insn_lm32);
573
574 lm32_add_reggroups (gdbarch);
575 set_gdbarch_register_reggroup_p (gdbarch, lm32_register_reggroup_p);
576
577 return gdbarch;
578 }
579
580 /* -Wmissing-prototypes */
581 extern initialize_file_ftype _initialize_lm32_tdep;
582
583 void
584 _initialize_lm32_tdep (void)
585 {
586 register_gdbarch_init (bfd_arch_lm32, lm32_gdbarch_init);
587 }
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