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a1217d97 | 1 | /* Target-machine dependent code for Nios II, for GDB. |
32d0add0 | 2 | Copyright (C) 2012-2015 Free Software Foundation, Inc. |
a1217d97 SL |
3 | Contributed by Peter Brookes (pbrookes@altera.com) |
4 | and Andrew Draper (adraper@altera.com). | |
5 | Contributed by Mentor Graphics, Inc. | |
6 | ||
7 | This file is part of GDB. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 3 of the License, or | |
12 | (at your option) any later version. | |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
21 | ||
22 | #include "defs.h" | |
23 | #include "frame.h" | |
24 | #include "frame-unwind.h" | |
25 | #include "frame-base.h" | |
26 | #include "trad-frame.h" | |
27 | #include "dwarf2-frame.h" | |
28 | #include "symtab.h" | |
29 | #include "inferior.h" | |
30 | #include "gdbtypes.h" | |
31 | #include "gdbcore.h" | |
32 | #include "gdbcmd.h" | |
33 | #include "osabi.h" | |
34 | #include "target.h" | |
35 | #include "dis-asm.h" | |
36 | #include "regcache.h" | |
37 | #include "value.h" | |
38 | #include "symfile.h" | |
39 | #include "arch-utils.h" | |
40 | #include "floatformat.h" | |
a1217d97 SL |
41 | #include "infcall.h" |
42 | #include "regset.h" | |
43 | #include "target-descriptions.h" | |
44 | ||
45 | /* To get entry_point_address. */ | |
46 | #include "objfiles.h" | |
47 | ||
48 | /* Nios II ISA specific encodings and macros. */ | |
49 | #include "opcode/nios2.h" | |
50 | ||
51 | /* Nios II specific header. */ | |
52 | #include "nios2-tdep.h" | |
53 | ||
54 | #include "features/nios2.c" | |
55 | ||
56 | /* Control debugging information emitted in this file. */ | |
57 | ||
58 | static int nios2_debug = 0; | |
59 | ||
60 | /* The following structures are used in the cache for prologue | |
61 | analysis; see the reg_value and reg_saved tables in | |
62 | struct nios2_unwind_cache, respectively. */ | |
63 | ||
64 | /* struct reg_value is used to record that a register has the same value | |
65 | as reg at the given offset from the start of a function. */ | |
66 | ||
67 | struct reg_value | |
68 | { | |
69 | int reg; | |
70 | unsigned int offset; | |
71 | }; | |
72 | ||
73 | /* struct reg_saved is used to record that a register value has been saved at | |
74 | basereg + addr, for basereg >= 0. If basereg < 0, that indicates | |
75 | that the register is not known to have been saved. Note that when | |
76 | basereg == NIOS2_Z_REGNUM (that is, r0, which holds value 0), | |
77 | addr is an absolute address. */ | |
78 | ||
79 | struct reg_saved | |
80 | { | |
81 | int basereg; | |
82 | CORE_ADDR addr; | |
83 | }; | |
84 | ||
85 | struct nios2_unwind_cache | |
86 | { | |
87 | /* The frame's base, optionally used by the high-level debug info. */ | |
88 | CORE_ADDR base; | |
89 | ||
90 | /* The previous frame's inner most stack address. Used as this | |
91 | frame ID's stack_addr. */ | |
92 | CORE_ADDR cfa; | |
93 | ||
94 | /* The address of the first instruction in this function. */ | |
95 | CORE_ADDR pc; | |
96 | ||
97 | /* Which register holds the return address for the frame. */ | |
98 | int return_regnum; | |
99 | ||
100 | /* Table indicating what changes have been made to each register. */ | |
101 | struct reg_value reg_value[NIOS2_NUM_REGS]; | |
102 | ||
103 | /* Table indicating where each register has been saved. */ | |
104 | struct reg_saved reg_saved[NIOS2_NUM_REGS]; | |
105 | }; | |
106 | ||
107 | ||
108 | /* This array is a mapping from Dwarf-2 register numbering to GDB's. */ | |
109 | ||
110 | static int nios2_dwarf2gdb_regno_map[] = | |
111 | { | |
112 | 0, 1, 2, 3, | |
113 | 4, 5, 6, 7, | |
114 | 8, 9, 10, 11, | |
115 | 12, 13, 14, 15, | |
116 | 16, 17, 18, 19, | |
117 | 20, 21, 22, 23, | |
118 | 24, 25, | |
119 | NIOS2_GP_REGNUM, /* 26 */ | |
120 | NIOS2_SP_REGNUM, /* 27 */ | |
121 | NIOS2_FP_REGNUM, /* 28 */ | |
122 | NIOS2_EA_REGNUM, /* 29 */ | |
123 | NIOS2_BA_REGNUM, /* 30 */ | |
124 | NIOS2_RA_REGNUM, /* 31 */ | |
125 | NIOS2_PC_REGNUM, /* 32 */ | |
126 | NIOS2_STATUS_REGNUM, /* 33 */ | |
127 | NIOS2_ESTATUS_REGNUM, /* 34 */ | |
128 | NIOS2_BSTATUS_REGNUM, /* 35 */ | |
129 | NIOS2_IENABLE_REGNUM, /* 36 */ | |
130 | NIOS2_IPENDING_REGNUM, /* 37 */ | |
131 | NIOS2_CPUID_REGNUM, /* 38 */ | |
132 | 39, /* CTL6 */ /* 39 */ | |
133 | NIOS2_EXCEPTION_REGNUM, /* 40 */ | |
134 | NIOS2_PTEADDR_REGNUM, /* 41 */ | |
135 | NIOS2_TLBACC_REGNUM, /* 42 */ | |
136 | NIOS2_TLBMISC_REGNUM, /* 43 */ | |
137 | NIOS2_ECCINJ_REGNUM, /* 44 */ | |
138 | NIOS2_BADADDR_REGNUM, /* 45 */ | |
139 | NIOS2_CONFIG_REGNUM, /* 46 */ | |
140 | NIOS2_MPUBASE_REGNUM, /* 47 */ | |
141 | NIOS2_MPUACC_REGNUM /* 48 */ | |
142 | }; | |
143 | ||
144 | ||
145 | /* Implement the dwarf2_reg_to_regnum gdbarch method. */ | |
146 | ||
147 | static int | |
148 | nios2_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int dw_reg) | |
149 | { | |
150 | if (dw_reg < 0 || dw_reg > NIOS2_NUM_REGS) | |
151 | { | |
1e52bda6 | 152 | warning (_("Dwarf-2 uses unmapped register #%d"), dw_reg); |
a1217d97 SL |
153 | return dw_reg; |
154 | } | |
155 | ||
156 | return nios2_dwarf2gdb_regno_map[dw_reg]; | |
157 | } | |
158 | ||
159 | /* Canonical names for the 49 registers. */ | |
160 | ||
161 | static const char *const nios2_reg_names[NIOS2_NUM_REGS] = | |
162 | { | |
163 | "zero", "at", "r2", "r3", "r4", "r5", "r6", "r7", | |
164 | "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15", | |
165 | "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23", | |
0b76b0ce | 166 | "et", "bt", "gp", "sp", "fp", "ea", "sstatus", "ra", |
a1217d97 SL |
167 | "pc", |
168 | "status", "estatus", "bstatus", "ienable", | |
169 | "ipending", "cpuid", "ctl6", "exception", | |
170 | "pteaddr", "tlbacc", "tlbmisc", "eccinj", | |
171 | "badaddr", "config", "mpubase", "mpuacc" | |
172 | }; | |
173 | ||
174 | /* Implement the register_name gdbarch method. */ | |
175 | ||
176 | static const char * | |
177 | nios2_register_name (struct gdbarch *gdbarch, int regno) | |
178 | { | |
179 | /* Use mnemonic aliases for GPRs. */ | |
180 | if (regno >= 0 && regno < NIOS2_NUM_REGS) | |
181 | return nios2_reg_names[regno]; | |
182 | else | |
183 | return tdesc_register_name (gdbarch, regno); | |
184 | } | |
185 | ||
186 | /* Implement the register_type gdbarch method. */ | |
187 | ||
188 | static struct type * | |
189 | nios2_register_type (struct gdbarch *gdbarch, int regno) | |
190 | { | |
191 | /* If the XML description has register information, use that to | |
192 | determine the register type. */ | |
193 | if (tdesc_has_registers (gdbarch_target_desc (gdbarch))) | |
194 | return tdesc_register_type (gdbarch, regno); | |
195 | ||
196 | if (regno == NIOS2_PC_REGNUM) | |
197 | return builtin_type (gdbarch)->builtin_func_ptr; | |
198 | else if (regno == NIOS2_SP_REGNUM) | |
199 | return builtin_type (gdbarch)->builtin_data_ptr; | |
200 | else | |
201 | return builtin_type (gdbarch)->builtin_uint32; | |
202 | } | |
203 | ||
204 | /* Given a return value in REGCACHE with a type VALTYPE, | |
205 | extract and copy its value into VALBUF. */ | |
206 | ||
207 | static void | |
208 | nios2_extract_return_value (struct gdbarch *gdbarch, struct type *valtype, | |
209 | struct regcache *regcache, gdb_byte *valbuf) | |
210 | { | |
211 | int len = TYPE_LENGTH (valtype); | |
212 | ||
213 | /* Return values of up to 8 bytes are returned in $r2 $r3. */ | |
214 | if (len <= register_size (gdbarch, NIOS2_R2_REGNUM)) | |
215 | regcache_cooked_read (regcache, NIOS2_R2_REGNUM, valbuf); | |
216 | else | |
217 | { | |
218 | gdb_assert (len <= (register_size (gdbarch, NIOS2_R2_REGNUM) | |
219 | + register_size (gdbarch, NIOS2_R3_REGNUM))); | |
220 | regcache_cooked_read (regcache, NIOS2_R2_REGNUM, valbuf); | |
221 | regcache_cooked_read (regcache, NIOS2_R3_REGNUM, valbuf + 4); | |
222 | } | |
223 | } | |
224 | ||
225 | /* Write into appropriate registers a function return value | |
226 | of type TYPE, given in virtual format. */ | |
227 | ||
228 | static void | |
229 | nios2_store_return_value (struct gdbarch *gdbarch, struct type *valtype, | |
230 | struct regcache *regcache, const gdb_byte *valbuf) | |
231 | { | |
232 | int len = TYPE_LENGTH (valtype); | |
233 | ||
234 | /* Return values of up to 8 bytes are returned in $r2 $r3. */ | |
235 | if (len <= register_size (gdbarch, NIOS2_R2_REGNUM)) | |
236 | regcache_cooked_write (regcache, NIOS2_R2_REGNUM, valbuf); | |
237 | else | |
238 | { | |
239 | gdb_assert (len <= (register_size (gdbarch, NIOS2_R2_REGNUM) | |
240 | + register_size (gdbarch, NIOS2_R3_REGNUM))); | |
241 | regcache_cooked_write (regcache, NIOS2_R2_REGNUM, valbuf); | |
242 | regcache_cooked_write (regcache, NIOS2_R3_REGNUM, valbuf + 4); | |
243 | } | |
244 | } | |
245 | ||
246 | ||
247 | /* Set up the default values of the registers. */ | |
248 | ||
249 | static void | |
250 | nios2_setup_default (struct nios2_unwind_cache *cache) | |
251 | { | |
252 | int i; | |
253 | ||
254 | for (i = 0; i < NIOS2_NUM_REGS; i++) | |
255 | { | |
256 | /* All registers start off holding their previous values. */ | |
257 | cache->reg_value[i].reg = i; | |
258 | cache->reg_value[i].offset = 0; | |
259 | ||
260 | /* All registers start off not saved. */ | |
261 | cache->reg_saved[i].basereg = -1; | |
262 | cache->reg_saved[i].addr = 0; | |
263 | } | |
264 | } | |
265 | ||
266 | /* Initialize the unwind cache. */ | |
267 | ||
268 | static void | |
269 | nios2_init_cache (struct nios2_unwind_cache *cache, CORE_ADDR pc) | |
270 | { | |
271 | cache->base = 0; | |
272 | cache->cfa = 0; | |
273 | cache->pc = pc; | |
274 | cache->return_regnum = NIOS2_RA_REGNUM; | |
275 | nios2_setup_default (cache); | |
276 | } | |
277 | ||
d53c26c7 SL |
278 | /* Read and identify an instruction at PC. If INSNP is non-null, |
279 | store the instruction word into that location. Return the opcode | |
280 | pointer or NULL if the memory couldn't be read or disassembled. */ | |
281 | ||
282 | static const struct nios2_opcode * | |
283 | nios2_fetch_insn (struct gdbarch *gdbarch, CORE_ADDR pc, | |
284 | unsigned int *insnp) | |
285 | { | |
286 | LONGEST memword; | |
287 | unsigned long mach = gdbarch_bfd_arch_info (gdbarch)->mach; | |
288 | unsigned int insn; | |
289 | ||
290 | if (!safe_read_memory_integer (pc, NIOS2_OPCODE_SIZE, | |
291 | gdbarch_byte_order (gdbarch), &memword)) | |
292 | return NULL; | |
293 | ||
294 | insn = (unsigned int) memword; | |
295 | if (insnp) | |
296 | *insnp = insn; | |
297 | return nios2_find_opcode_hash (insn, mach); | |
298 | } | |
299 | ||
300 | ||
301 | /* Match and disassemble an ADD-type instruction, with 3 register operands. | |
302 | Returns true on success, and fills in the operand pointers. */ | |
303 | ||
304 | static int | |
305 | nios2_match_add (uint32_t insn, const struct nios2_opcode *op, | |
306 | unsigned long mach, int *ra, int *rb, int *rc) | |
307 | { | |
308 | if (op->match == MATCH_R1_ADD || op->match == MATCH_R1_MOV) | |
309 | { | |
310 | *ra = GET_IW_R_A (insn); | |
311 | *rb = GET_IW_R_B (insn); | |
312 | *rc = GET_IW_R_C (insn); | |
313 | return 1; | |
314 | } | |
315 | return 0; | |
316 | } | |
317 | ||
318 | /* Match and disassemble a SUB-type instruction, with 3 register operands. | |
319 | Returns true on success, and fills in the operand pointers. */ | |
320 | ||
321 | static int | |
322 | nios2_match_sub (uint32_t insn, const struct nios2_opcode *op, | |
323 | unsigned long mach, int *ra, int *rb, int *rc) | |
324 | { | |
325 | if (op->match == MATCH_R1_SUB) | |
326 | { | |
327 | *ra = GET_IW_R_A (insn); | |
328 | *rb = GET_IW_R_B (insn); | |
329 | *rc = GET_IW_R_C (insn); | |
330 | return 1; | |
331 | } | |
332 | return 0; | |
333 | } | |
334 | ||
335 | /* Match and disassemble an ADDI-type instruction, with 2 register operands | |
336 | and one immediate operand. | |
337 | Returns true on success, and fills in the operand pointers. */ | |
338 | ||
339 | static int | |
340 | nios2_match_addi (uint32_t insn, const struct nios2_opcode *op, | |
341 | unsigned long mach, int *ra, int *rb, int *imm) | |
342 | { | |
343 | if (op->match == MATCH_R1_ADDI) | |
344 | { | |
345 | *ra = GET_IW_I_A (insn); | |
346 | *rb = GET_IW_I_B (insn); | |
347 | *imm = (signed) (GET_IW_I_IMM16 (insn) << 16) >> 16; | |
348 | return 1; | |
349 | } | |
350 | return 0; | |
351 | } | |
352 | ||
353 | /* Match and disassemble an ORHI-type instruction, with 2 register operands | |
354 | and one unsigned immediate operand. | |
355 | Returns true on success, and fills in the operand pointers. */ | |
356 | ||
357 | static int | |
358 | nios2_match_orhi (uint32_t insn, const struct nios2_opcode *op, | |
359 | unsigned long mach, int *ra, int *rb, unsigned int *uimm) | |
360 | { | |
361 | if (op->match == MATCH_R1_ORHI) | |
362 | { | |
363 | *ra = GET_IW_I_A (insn); | |
364 | *rb = GET_IW_I_B (insn); | |
365 | *uimm = GET_IW_I_IMM16 (insn); | |
366 | return 1; | |
367 | } | |
368 | return 0; | |
369 | } | |
370 | ||
371 | /* Match and disassemble a STW-type instruction, with 2 register operands | |
372 | and one immediate operand. | |
373 | Returns true on success, and fills in the operand pointers. */ | |
374 | ||
375 | static int | |
376 | nios2_match_stw (uint32_t insn, const struct nios2_opcode *op, | |
377 | unsigned long mach, int *ra, int *rb, int *imm) | |
378 | { | |
379 | if (op->match == MATCH_R1_STW || op->match == MATCH_R1_STWIO) | |
380 | { | |
381 | *ra = GET_IW_I_A (insn); | |
382 | *rb = GET_IW_I_B (insn); | |
383 | *imm = (signed) (GET_IW_I_IMM16 (insn) << 16) >> 16; | |
384 | return 1; | |
385 | } | |
386 | return 0; | |
387 | } | |
388 | ||
389 | /* Match and disassemble a LDW-type instruction, with 2 register operands | |
390 | and one immediate operand. | |
391 | Returns true on success, and fills in the operand pointers. */ | |
392 | ||
393 | static int | |
394 | nios2_match_ldw (uint32_t insn, const struct nios2_opcode *op, | |
395 | unsigned long mach, int *ra, int *rb, int *imm) | |
396 | { | |
397 | if (op->match == MATCH_R1_LDW || op->match == MATCH_R1_LDWIO) | |
398 | { | |
399 | *ra = GET_IW_I_A (insn); | |
400 | *rb = GET_IW_I_B (insn); | |
401 | *imm = (signed) (GET_IW_I_IMM16 (insn) << 16) >> 16; | |
402 | return 1; | |
403 | } | |
404 | return 0; | |
405 | } | |
406 | ||
407 | /* Match and disassemble a RDCTL instruction, with 2 register operands. | |
408 | Returns true on success, and fills in the operand pointers. */ | |
409 | ||
410 | static int | |
411 | nios2_match_rdctl (uint32_t insn, const struct nios2_opcode *op, | |
412 | unsigned long mach, int *ra, int *rc) | |
413 | { | |
414 | if (op->match == MATCH_R1_RDCTL) | |
415 | { | |
416 | *ra = GET_IW_R_IMM5 (insn); | |
417 | *rc = GET_IW_R_C (insn); | |
418 | return 1; | |
419 | } | |
420 | return 0; | |
421 | } | |
422 | ||
423 | ||
424 | /* Match and disassemble a branch instruction, with (potentially) | |
425 | 2 register operands and one immediate operand. | |
426 | Returns true on success, and fills in the operand pointers. */ | |
427 | ||
428 | enum branch_condition { | |
429 | branch_none, | |
430 | branch_eq, | |
431 | branch_ne, | |
432 | branch_ge, | |
433 | branch_geu, | |
434 | branch_lt, | |
435 | branch_ltu | |
436 | }; | |
437 | ||
438 | static int | |
439 | nios2_match_branch (uint32_t insn, const struct nios2_opcode *op, | |
440 | unsigned long mach, int *ra, int *rb, int *imm, | |
441 | enum branch_condition *cond) | |
442 | { | |
443 | switch (op->match) | |
444 | { | |
445 | case MATCH_R1_BR: | |
446 | *cond = branch_none; | |
447 | break; | |
448 | case MATCH_R1_BEQ: | |
449 | *cond = branch_eq; | |
450 | break; | |
451 | case MATCH_R1_BNE: | |
452 | *cond = branch_ne; | |
453 | break; | |
454 | case MATCH_R1_BGE: | |
455 | *cond = branch_ge; | |
456 | break; | |
457 | case MATCH_R1_BGEU: | |
458 | *cond = branch_geu; | |
459 | break; | |
460 | case MATCH_R1_BLT: | |
461 | *cond = branch_lt; | |
462 | break; | |
463 | case MATCH_R1_BLTU: | |
464 | *cond = branch_ltu; | |
465 | break; | |
466 | default: | |
467 | return 0; | |
468 | } | |
469 | *imm = (signed) (GET_IW_I_IMM16 (insn) << 16) >> 16; | |
470 | *ra = GET_IW_I_A (insn); | |
471 | *rb = GET_IW_I_B (insn); | |
472 | return 1; | |
473 | } | |
474 | ||
475 | /* Match and disassemble a direct jump instruction, with an | |
476 | unsigned operand. Returns true on success, and fills in the operand | |
477 | pointer. */ | |
478 | ||
479 | static int | |
480 | nios2_match_jmpi (uint32_t insn, const struct nios2_opcode *op, | |
481 | unsigned long mach, unsigned int *uimm) | |
482 | { | |
483 | if (op->match == MATCH_R1_JMPI) | |
484 | { | |
485 | *uimm = GET_IW_J_IMM26 (insn) << 2; | |
486 | return 1; | |
487 | } | |
488 | return 0; | |
489 | } | |
490 | ||
491 | /* Match and disassemble a direct call instruction, with an | |
492 | unsigned operand. Returns true on success, and fills in the operand | |
493 | pointer. */ | |
494 | ||
495 | static int | |
496 | nios2_match_calli (uint32_t insn, const struct nios2_opcode *op, | |
497 | unsigned long mach, unsigned int *uimm) | |
498 | { | |
499 | if (op->match == MATCH_R1_CALL) | |
500 | { | |
501 | *uimm = GET_IW_J_IMM26 (insn) << 2; | |
502 | return 1; | |
503 | } | |
504 | return 0; | |
505 | } | |
506 | ||
507 | /* Match and disassemble an indirect jump instruction, with a | |
508 | (possibly implicit) register operand. Returns true on success, and fills | |
509 | in the operand pointer. */ | |
510 | ||
511 | static int | |
512 | nios2_match_jmpr (uint32_t insn, const struct nios2_opcode *op, | |
513 | unsigned long mach, int *ra) | |
514 | { | |
515 | switch (op->match) | |
516 | { | |
517 | case MATCH_R1_JMP: | |
518 | *ra = GET_IW_I_A (insn); | |
519 | return 1; | |
520 | case MATCH_R1_RET: | |
521 | *ra = NIOS2_RA_REGNUM; | |
522 | return 1; | |
523 | case MATCH_R1_ERET: | |
524 | *ra = NIOS2_EA_REGNUM; | |
525 | return 1; | |
526 | case MATCH_R1_BRET: | |
527 | *ra = NIOS2_BA_REGNUM; | |
528 | return 1; | |
529 | default: | |
530 | return 0; | |
531 | } | |
532 | } | |
533 | ||
534 | /* Match and disassemble an indirect call instruction, with a register | |
535 | operand. Returns true on success, and fills in the operand pointer. */ | |
536 | ||
537 | static int | |
538 | nios2_match_callr (uint32_t insn, const struct nios2_opcode *op, | |
539 | unsigned long mach, int *ra) | |
540 | { | |
541 | if (op->match == MATCH_R1_CALLR) | |
542 | { | |
543 | *ra = GET_IW_I_A (insn); | |
544 | return 1; | |
545 | } | |
546 | return 0; | |
547 | } | |
548 | ||
549 | /* Match and disassemble a break instruction, with an unsigned operand. | |
550 | Returns true on success, and fills in the operand pointer. */ | |
551 | ||
552 | static int | |
553 | nios2_match_break (uint32_t insn, const struct nios2_opcode *op, | |
554 | unsigned long mach, unsigned int *uimm) | |
555 | { | |
556 | if (op->match == MATCH_R1_BREAK) | |
557 | { | |
558 | *uimm = GET_IW_R_IMM5 (insn); | |
559 | return 1; | |
560 | } | |
561 | return 0; | |
562 | } | |
563 | ||
564 | /* Match and disassemble a trap instruction, with an unsigned operand. | |
565 | Returns true on success, and fills in the operand pointer. */ | |
566 | ||
567 | static int | |
568 | nios2_match_trap (uint32_t insn, const struct nios2_opcode *op, | |
569 | unsigned long mach, unsigned int *uimm) | |
570 | { | |
571 | if (op->match == MATCH_R1_TRAP) | |
572 | { | |
573 | *uimm = GET_IW_R_IMM5 (insn); | |
574 | return 1; | |
575 | } | |
576 | return 0; | |
577 | } | |
578 | ||
a1217d97 SL |
579 | /* Helper function to identify when we're in a function epilogue; |
580 | that is, the part of the function from the point at which the | |
d53c26c7 SL |
581 | stack adjustments are made, to the return or sibcall. |
582 | Note that we may have several stack adjustment instructions, and | |
583 | this function needs to test whether the stack teardown has already | |
584 | started before current_pc, not whether it has completed. */ | |
a1217d97 SL |
585 | |
586 | static int | |
587 | nios2_in_epilogue_p (struct gdbarch *gdbarch, | |
588 | CORE_ADDR current_pc, | |
589 | CORE_ADDR start_pc) | |
590 | { | |
d53c26c7 | 591 | unsigned long mach = gdbarch_bfd_arch_info (gdbarch)->mach; |
7f1659b5 SL |
592 | /* Maximum number of possibly-epilogue instructions to check. |
593 | Note that this number should not be too large, else we can | |
594 | potentially end up iterating through unmapped memory. */ | |
595 | int ninsns, max_insns = 5; | |
d53c26c7 SL |
596 | unsigned int insn; |
597 | const struct nios2_opcode *op = NULL; | |
598 | unsigned int uimm; | |
599 | int imm; | |
600 | int ra, rb, rc; | |
601 | enum branch_condition cond; | |
7f1659b5 | 602 | CORE_ADDR pc; |
a1217d97 SL |
603 | |
604 | /* There has to be a previous instruction in the function. */ | |
7f1659b5 SL |
605 | if (current_pc <= start_pc) |
606 | return 0; | |
607 | ||
608 | /* Find the previous instruction before current_pc. | |
609 | For the moment we will assume that all instructions are the | |
610 | same size here. */ | |
611 | pc = current_pc - NIOS2_OPCODE_SIZE; | |
d53c26c7 | 612 | |
7f1659b5 SL |
613 | /* Beginning with the previous instruction we just located, check whether |
614 | we are in a sequence of at least one stack adjustment instruction. | |
615 | Possible instructions here include: | |
d53c26c7 SL |
616 | ADDI sp, sp, n |
617 | ADD sp, sp, rn | |
618 | LDW sp, n(sp) */ | |
7f1659b5 SL |
619 | for (ninsns = 0; ninsns < max_insns; ninsns++) |
620 | { | |
621 | int ok = 0; | |
622 | ||
623 | /* Fetch the insn at pc. */ | |
624 | op = nios2_fetch_insn (gdbarch, pc, &insn); | |
d53c26c7 SL |
625 | if (op == NULL) |
626 | return 0; | |
7f1659b5 | 627 | pc += op->size; |
d53c26c7 SL |
628 | |
629 | /* Was it a stack adjustment? */ | |
630 | if (nios2_match_addi (insn, op, mach, &ra, &rb, &imm)) | |
631 | ok = (rb == NIOS2_SP_REGNUM); | |
632 | else if (nios2_match_add (insn, op, mach, &ra, &rb, &rc)) | |
633 | ok = (rc == NIOS2_SP_REGNUM); | |
634 | else if (nios2_match_ldw (insn, op, mach, &ra, &rb, &imm)) | |
635 | ok = (rb == NIOS2_SP_REGNUM); | |
636 | if (!ok) | |
7f1659b5 | 637 | break; |
a1217d97 | 638 | } |
7f1659b5 SL |
639 | |
640 | /* No stack adjustments found. */ | |
641 | if (ninsns == 0) | |
642 | return 0; | |
643 | ||
644 | /* We found more stack adjustments than we expect GCC to be generating. | |
645 | Since it looks like a stack unwind might be in progress tell GDB to | |
646 | treat it as such. */ | |
647 | if (ninsns == max_insns) | |
648 | return 1; | |
649 | ||
650 | /* The next instruction following the stack adjustments must be a | |
651 | return, jump, or unconditional branch. */ | |
652 | if (nios2_match_jmpr (insn, op, mach, &ra) | |
653 | || nios2_match_jmpi (insn, op, mach, &uimm) | |
654 | || (nios2_match_branch (insn, op, mach, &ra, &rb, &imm, &cond) | |
655 | && cond == branch_none)) | |
656 | return 1; | |
657 | ||
a1217d97 SL |
658 | return 0; |
659 | } | |
660 | ||
c9cf6e20 | 661 | /* Implement the stack_frame_destroyed_p gdbarch method. */ |
a1217d97 SL |
662 | |
663 | static int | |
c9cf6e20 | 664 | nios2_stack_frame_destroyed_p (struct gdbarch *gdbarch, CORE_ADDR pc) |
a1217d97 SL |
665 | { |
666 | CORE_ADDR func_addr; | |
667 | ||
668 | if (find_pc_partial_function (pc, NULL, &func_addr, NULL)) | |
669 | return nios2_in_epilogue_p (gdbarch, pc, func_addr); | |
670 | ||
671 | return 0; | |
672 | } | |
673 | ||
a1217d97 SL |
674 | /* Do prologue analysis, returning the PC of the first instruction |
675 | after the function prologue. Assumes CACHE has already been | |
676 | initialized. THIS_FRAME can be null, in which case we are only | |
677 | interested in skipping the prologue. Otherwise CACHE is filled in | |
678 | from the frame information. | |
679 | ||
d53c26c7 SL |
680 | The prologue may consist of the following parts: |
681 | 1) Profiling instrumentation. For non-PIC code it looks like: | |
a1217d97 SL |
682 | mov r8, ra |
683 | call mcount | |
684 | mov ra, r8 | |
685 | ||
d53c26c7 SL |
686 | 2) A stack adjustment and save of R4-R7 for varargs functions. |
687 | This is typically merged with item 3. | |
688 | ||
689 | 3) A stack adjustment and save of the callee-saved registers; | |
690 | typically an explicit SP decrement and individual register | |
691 | saves. | |
692 | ||
693 | There may also be a stack switch here in an exception handler | |
694 | in place of a stack adjustment. It looks like: | |
a1217d97 SL |
695 | movhi rx, %hiadj(newstack) |
696 | addhi rx, rx, %lo(newstack) | |
697 | stw sp, constant(rx) | |
698 | mov sp, rx | |
699 | ||
9aaf8e3a | 700 | 4) A frame pointer save, which can be either a MOV or ADDI. |
d53c26c7 | 701 | |
9aaf8e3a SL |
702 | 5) A further stack pointer adjustment. This is normally included |
703 | adjustment in step 3 unless the total adjustment is too large | |
d53c26c7 SL |
704 | to be done in one step. |
705 | ||
706 | 7) A stack overflow check, which can take either of these forms: | |
a1217d97 | 707 | bgeu sp, rx, +8 |
9aaf8e3a | 708 | trap 3 |
a1217d97 SL |
709 | or |
710 | bltu sp, rx, .Lstack_overflow | |
711 | ... | |
712 | .Lstack_overflow: | |
9aaf8e3a SL |
713 | trap 3 |
714 | ||
715 | Older versions of GCC emitted "break 3" instead of "trap 3" here, | |
716 | so we check for both cases. | |
717 | ||
718 | Older GCC versions emitted stack overflow checks after the SP | |
719 | adjustments in both steps 3 and 4. Starting with GCC 6, there is | |
720 | at most one overflow check, which is placed before the first | |
721 | stack adjustment for R2 CDX and after the first stack adjustment | |
722 | otherwise. | |
a1217d97 | 723 | |
d53c26c7 SL |
724 | The prologue instructions may be combined or interleaved with other |
725 | instructions. | |
a1217d97 SL |
726 | |
727 | To cope with all this variability we decode all the instructions | |
d53c26c7 SL |
728 | from the start of the prologue until we hit an instruction that |
729 | cannot possibly be a prologue instruction, such as a branch, call, | |
730 | return, or epilogue instruction. The prologue is considered to end | |
731 | at the last instruction that can definitely be considered a | |
732 | prologue instruction. */ | |
a1217d97 SL |
733 | |
734 | static CORE_ADDR | |
735 | nios2_analyze_prologue (struct gdbarch *gdbarch, const CORE_ADDR start_pc, | |
736 | const CORE_ADDR current_pc, | |
737 | struct nios2_unwind_cache *cache, | |
738 | struct frame_info *this_frame) | |
739 | { | |
d53c26c7 | 740 | /* Maximum number of possibly-prologue instructions to check. |
a1217d97 SL |
741 | Note that this number should not be too large, else we can |
742 | potentially end up iterating through unmapped memory. */ | |
d53c26c7 | 743 | int ninsns, max_insns = 50; |
a1217d97 SL |
744 | int regno; |
745 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
d53c26c7 | 746 | unsigned long mach = gdbarch_bfd_arch_info (gdbarch)->mach; |
a1217d97 SL |
747 | |
748 | /* Does the frame set up the FP register? */ | |
749 | int base_reg = 0; | |
750 | ||
751 | struct reg_value *value = cache->reg_value; | |
752 | struct reg_value temp_value[NIOS2_NUM_REGS]; | |
753 | ||
754 | int i; | |
755 | ||
756 | /* Save the starting PC so we can correct the pc after running | |
757 | through the prolog, using symbol info. */ | |
758 | CORE_ADDR pc = start_pc; | |
759 | ||
760 | /* Is this an exception handler? */ | |
761 | int exception_handler = 0; | |
762 | ||
763 | /* What was the original value of SP (or fake original value for | |
764 | functions which switch stacks? */ | |
765 | CORE_ADDR frame_high; | |
766 | ||
d53c26c7 | 767 | /* The last definitely-prologue instruction seen. */ |
a1217d97 SL |
768 | CORE_ADDR prologue_end; |
769 | ||
770 | /* Is this the innermost function? */ | |
771 | int innermost = (this_frame ? (frame_relative_level (this_frame) == 0) : 1); | |
772 | ||
773 | if (nios2_debug) | |
774 | fprintf_unfiltered (gdb_stdlog, | |
775 | "{ nios2_analyze_prologue start=%s, current=%s ", | |
776 | paddress (gdbarch, start_pc), | |
777 | paddress (gdbarch, current_pc)); | |
778 | ||
779 | /* Set up the default values of the registers. */ | |
780 | nios2_setup_default (cache); | |
a1217d97 SL |
781 | |
782 | /* Find the prologue instructions. */ | |
d53c26c7 SL |
783 | prologue_end = start_pc; |
784 | for (ninsns = 0; ninsns < max_insns; ninsns++) | |
a1217d97 SL |
785 | { |
786 | /* Present instruction. */ | |
787 | uint32_t insn; | |
d53c26c7 SL |
788 | const struct nios2_opcode *op; |
789 | int ra, rb, rc, imm; | |
790 | unsigned int uimm; | |
791 | unsigned int reglist; | |
792 | int wb, ret; | |
793 | enum branch_condition cond; | |
a1217d97 SL |
794 | |
795 | if (pc == current_pc) | |
796 | { | |
797 | /* When we reach the current PC we must save the current | |
798 | register state (for the backtrace) but keep analysing | |
799 | because there might be more to find out (eg. is this an | |
800 | exception handler). */ | |
801 | memcpy (temp_value, value, sizeof (temp_value)); | |
802 | value = temp_value; | |
803 | if (nios2_debug) | |
804 | fprintf_unfiltered (gdb_stdlog, "*"); | |
805 | } | |
806 | ||
d53c26c7 SL |
807 | op = nios2_fetch_insn (gdbarch, pc, &insn); |
808 | ||
809 | /* Unknown opcode? Stop scanning. */ | |
810 | if (op == NULL) | |
811 | break; | |
812 | pc += op->size; | |
a1217d97 SL |
813 | |
814 | if (nios2_debug) | |
815 | fprintf_unfiltered (gdb_stdlog, "[%08X]", insn); | |
816 | ||
817 | /* The following instructions can appear in the prologue. */ | |
818 | ||
d53c26c7 | 819 | if (nios2_match_add (insn, op, mach, &ra, &rb, &rc)) |
a1217d97 SL |
820 | { |
821 | /* ADD rc, ra, rb (also used for MOV) */ | |
a1217d97 SL |
822 | if (rc == NIOS2_SP_REGNUM |
823 | && rb == 0 | |
824 | && value[ra].reg == cache->reg_saved[NIOS2_SP_REGNUM].basereg) | |
825 | { | |
826 | /* If the previous value of SP is available somewhere | |
827 | near the new stack pointer value then this is a | |
828 | stack switch. */ | |
829 | ||
830 | /* If any registers were saved on the stack before then | |
831 | we can't backtrace into them now. */ | |
832 | for (i = 0 ; i < NIOS2_NUM_REGS ; i++) | |
833 | { | |
834 | if (cache->reg_saved[i].basereg == NIOS2_SP_REGNUM) | |
835 | cache->reg_saved[i].basereg = -1; | |
836 | if (value[i].reg == NIOS2_SP_REGNUM) | |
837 | value[i].reg = -1; | |
838 | } | |
839 | ||
840 | /* Create a fake "high water mark" 4 bytes above where SP | |
841 | was stored and fake up the registers to be consistent | |
842 | with that. */ | |
843 | value[NIOS2_SP_REGNUM].reg = NIOS2_SP_REGNUM; | |
844 | value[NIOS2_SP_REGNUM].offset | |
845 | = (value[ra].offset | |
846 | - cache->reg_saved[NIOS2_SP_REGNUM].addr | |
847 | - 4); | |
848 | cache->reg_saved[NIOS2_SP_REGNUM].basereg = NIOS2_SP_REGNUM; | |
849 | cache->reg_saved[NIOS2_SP_REGNUM].addr = -4; | |
850 | } | |
851 | ||
aa489395 SL |
852 | else if (rc == NIOS2_SP_REGNUM && ra == NIOS2_FP_REGNUM) |
853 | /* This is setting SP from FP. This only happens in the | |
854 | function epilogue. */ | |
855 | break; | |
856 | ||
a1217d97 SL |
857 | else if (rc != 0) |
858 | { | |
859 | if (value[rb].reg == 0) | |
860 | value[rc].reg = value[ra].reg; | |
861 | else if (value[ra].reg == 0) | |
862 | value[rc].reg = value[rb].reg; | |
863 | else | |
864 | value[rc].reg = -1; | |
865 | value[rc].offset = value[ra].offset + value[rb].offset; | |
866 | } | |
a1217d97 | 867 | |
aa489395 SL |
868 | /* The add/move is only considered a prologue instruction |
869 | if the destination is SP or FP. */ | |
870 | if (rc == NIOS2_SP_REGNUM || rc == NIOS2_FP_REGNUM) | |
871 | prologue_end = pc; | |
d53c26c7 SL |
872 | } |
873 | ||
874 | else if (nios2_match_sub (insn, op, mach, &ra, &rb, &rc)) | |
a1217d97 SL |
875 | { |
876 | /* SUB rc, ra, rb */ | |
aa489395 SL |
877 | if (rc == NIOS2_SP_REGNUM && rb == NIOS2_SP_REGNUM |
878 | && value[rc].reg != 0) | |
879 | /* If we are decrementing the SP by a non-constant amount, | |
880 | this is alloca, not part of the prologue. */ | |
881 | break; | |
882 | else if (rc != 0) | |
a1217d97 SL |
883 | { |
884 | if (value[rb].reg == 0) | |
885 | value[rc].reg = value[ra].reg; | |
886 | else | |
887 | value[rc].reg = -1; | |
888 | value[rc].offset = value[ra].offset - value[rb].offset; | |
889 | } | |
890 | } | |
891 | ||
d53c26c7 | 892 | else if (nios2_match_addi (insn, op, mach, &ra, &rb, &imm)) |
a1217d97 | 893 | { |
d53c26c7 | 894 | /* ADDI rb, ra, imm */ |
a1217d97 | 895 | |
aa489395 | 896 | /* A positive stack adjustment has to be part of the epilogue. */ |
a1217d97 | 897 | if (rb == NIOS2_SP_REGNUM |
aa489395 SL |
898 | && (imm > 0 || value[ra].reg != NIOS2_SP_REGNUM)) |
899 | break; | |
900 | ||
901 | /* Likewise restoring SP from FP. */ | |
902 | else if (rb == NIOS2_SP_REGNUM && ra == NIOS2_FP_REGNUM) | |
a1217d97 SL |
903 | break; |
904 | ||
905 | if (rb != 0) | |
906 | { | |
907 | value[rb].reg = value[ra].reg; | |
d53c26c7 | 908 | value[rb].offset = value[ra].offset + imm; |
a1217d97 SL |
909 | } |
910 | ||
aa489395 SL |
911 | /* The add is only considered a prologue instruction |
912 | if the destination is SP or FP. */ | |
913 | if (rb == NIOS2_SP_REGNUM || rb == NIOS2_FP_REGNUM) | |
914 | prologue_end = pc; | |
a1217d97 SL |
915 | } |
916 | ||
d53c26c7 | 917 | else if (nios2_match_orhi (insn, op, mach, &ra, &rb, &uimm)) |
a1217d97 | 918 | { |
d53c26c7 | 919 | /* ORHI rb, ra, uimm (also used for MOVHI) */ |
a1217d97 SL |
920 | if (rb != 0) |
921 | { | |
922 | value[rb].reg = (value[ra].reg == 0) ? 0 : -1; | |
d53c26c7 | 923 | value[rb].offset = value[ra].offset | (uimm << 16); |
a1217d97 SL |
924 | } |
925 | } | |
926 | ||
d53c26c7 | 927 | else if (nios2_match_stw (insn, op, mach, &ra, &rb, &imm)) |
a1217d97 | 928 | { |
d53c26c7 | 929 | /* STW rb, imm(ra) */ |
a1217d97 | 930 | |
d53c26c7 | 931 | /* Are we storing the original value of a register to the stack? |
a1217d97 SL |
932 | For exception handlers the value of EA-4 (return |
933 | address from interrupts etc) is sometimes stored. */ | |
934 | int orig = value[rb].reg; | |
935 | if (orig > 0 | |
936 | && (value[rb].offset == 0 | |
d53c26c7 | 937 | || (orig == NIOS2_EA_REGNUM && value[rb].offset == -4)) |
e1b5381f | 938 | && value[ra].reg == NIOS2_SP_REGNUM) |
d53c26c7 SL |
939 | { |
940 | if (pc < current_pc) | |
a1217d97 | 941 | { |
d53c26c7 SL |
942 | /* Save off callee saved registers. */ |
943 | cache->reg_saved[orig].basereg = value[ra].reg; | |
944 | cache->reg_saved[orig].addr = value[ra].offset + imm; | |
a1217d97 | 945 | } |
d53c26c7 SL |
946 | |
947 | prologue_end = pc; | |
948 | ||
949 | if (orig == NIOS2_EA_REGNUM || orig == NIOS2_ESTATUS_REGNUM) | |
950 | exception_handler = 1; | |
a1217d97 SL |
951 | } |
952 | else | |
d53c26c7 SL |
953 | /* Non-stack memory writes cannot appear in the prologue. */ |
954 | break; | |
a1217d97 SL |
955 | } |
956 | ||
d53c26c7 | 957 | else if (nios2_match_rdctl (insn, op, mach, &ra, &rc)) |
a1217d97 | 958 | { |
d53c26c7 SL |
959 | /* RDCTL rC, ctlN |
960 | This can appear in exception handlers in combination with | |
961 | a subsequent save to the stack frame. */ | |
a1217d97 SL |
962 | if (rc != 0) |
963 | { | |
d53c26c7 | 964 | value[rc].reg = NIOS2_STATUS_REGNUM + ra; |
a1217d97 SL |
965 | value[rc].offset = 0; |
966 | } | |
a1217d97 SL |
967 | } |
968 | ||
d53c26c7 | 969 | else if (nios2_match_calli (insn, op, mach, &uimm)) |
a1217d97 | 970 | { |
d53c26c7 SL |
971 | if (value[8].reg == NIOS2_RA_REGNUM |
972 | && value[8].offset == 0 | |
973 | && value[NIOS2_SP_REGNUM].reg == NIOS2_SP_REGNUM | |
974 | && value[NIOS2_SP_REGNUM].offset == 0) | |
975 | { | |
976 | /* A CALL instruction. This is treated as a call to mcount | |
977 | if ra has been stored into r8 beforehand and if it's | |
978 | before the stack adjust. | |
979 | Note mcount corrupts r2-r3, r9-r15 & ra. */ | |
980 | for (i = 2 ; i <= 3 ; i++) | |
981 | value[i].reg = -1; | |
982 | for (i = 9 ; i <= 15 ; i++) | |
983 | value[i].reg = -1; | |
984 | value[NIOS2_RA_REGNUM].reg = -1; | |
985 | ||
986 | prologue_end = pc; | |
987 | } | |
a1217d97 | 988 | |
d53c26c7 | 989 | /* Other calls are not part of the prologue. */ |
a1217d97 | 990 | else |
d53c26c7 | 991 | break; |
a1217d97 SL |
992 | } |
993 | ||
d53c26c7 | 994 | else if (nios2_match_branch (insn, op, mach, &ra, &rb, &imm, &cond)) |
a1217d97 | 995 | { |
d53c26c7 SL |
996 | /* Branches not involving a stack overflow check aren't part of |
997 | the prologue. */ | |
998 | if (ra != NIOS2_SP_REGNUM) | |
999 | break; | |
1000 | else if (cond == branch_geu) | |
a1217d97 | 1001 | { |
d53c26c7 | 1002 | /* BGEU sp, rx, +8 |
9aaf8e3a | 1003 | TRAP 3 (or BREAK 3) |
d53c26c7 SL |
1004 | This instruction sequence is used in stack checking; |
1005 | we can ignore it. */ | |
1006 | unsigned int next_insn; | |
1007 | const struct nios2_opcode *next_op | |
1008 | = nios2_fetch_insn (gdbarch, pc, &next_insn); | |
1009 | if (next_op != NULL | |
9aaf8e3a SL |
1010 | && (nios2_match_trap (next_insn, op, mach, &uimm) |
1011 | || nios2_match_break (next_insn, op, mach, &uimm))) | |
d53c26c7 SL |
1012 | pc += next_op->size; |
1013 | else | |
1014 | break; | |
a1217d97 | 1015 | } |
d53c26c7 SL |
1016 | else if (cond == branch_ltu) |
1017 | { | |
1018 | /* BLTU sp, rx, .Lstackoverflow | |
9aaf8e3a SL |
1019 | If the location branched to holds a TRAP or BREAK |
1020 | instruction then this is also stack overflow detection. */ | |
d53c26c7 SL |
1021 | unsigned int next_insn; |
1022 | const struct nios2_opcode *next_op | |
1023 | = nios2_fetch_insn (gdbarch, pc + imm, &next_insn); | |
1024 | if (next_op != NULL | |
9aaf8e3a SL |
1025 | && (nios2_match_trap (next_insn, op, mach, &uimm) |
1026 | || nios2_match_break (next_insn, op, mach, &uimm))) | |
d53c26c7 SL |
1027 | ; |
1028 | else | |
1029 | break; | |
1030 | } | |
1031 | else | |
1032 | break; | |
a1217d97 SL |
1033 | } |
1034 | ||
9aaf8e3a | 1035 | /* All other calls, jumps, returns, TRAPs, or BREAKs terminate |
d53c26c7 SL |
1036 | the prologue. */ |
1037 | else if (nios2_match_callr (insn, op, mach, &ra) | |
1038 | || nios2_match_jmpr (insn, op, mach, &ra) | |
9aaf8e3a SL |
1039 | || nios2_match_jmpi (insn, op, mach, &uimm) |
1040 | || nios2_match_trap (insn, op, mach, &uimm) | |
1041 | || nios2_match_break (insn, op, mach, &uimm)) | |
d53c26c7 | 1042 | break; |
a1217d97 SL |
1043 | } |
1044 | ||
1045 | /* If THIS_FRAME is NULL, we are being called from skip_prologue | |
1046 | and are only interested in the PROLOGUE_END value, so just | |
1047 | return that now and skip over the cache updates, which depend | |
1048 | on having frame information. */ | |
1049 | if (this_frame == NULL) | |
1050 | return prologue_end; | |
1051 | ||
1052 | /* If we are in the function epilogue and have already popped | |
1053 | registers off the stack in preparation for returning, then we | |
1054 | want to go back to the original register values. */ | |
1055 | if (innermost && nios2_in_epilogue_p (gdbarch, current_pc, start_pc)) | |
1056 | nios2_setup_default (cache); | |
1057 | ||
1058 | /* Exception handlers use a different return address register. */ | |
1059 | if (exception_handler) | |
1060 | cache->return_regnum = NIOS2_EA_REGNUM; | |
1061 | ||
1062 | if (nios2_debug) | |
1063 | fprintf_unfiltered (gdb_stdlog, "\n-> retreg=%d, ", cache->return_regnum); | |
1064 | ||
1065 | if (cache->reg_value[NIOS2_FP_REGNUM].reg == NIOS2_SP_REGNUM) | |
1066 | /* If the FP now holds an offset from the CFA then this is a | |
1067 | normal frame which uses the frame pointer. */ | |
1068 | base_reg = NIOS2_FP_REGNUM; | |
1069 | else if (cache->reg_value[NIOS2_SP_REGNUM].reg == NIOS2_SP_REGNUM) | |
1070 | /* FP doesn't hold an offset from the CFA. If SP still holds an | |
1071 | offset from the CFA then we might be in a function which omits | |
1072 | the frame pointer, or we might be partway through the prologue. | |
1073 | In both cases we can find the CFA using SP. */ | |
1074 | base_reg = NIOS2_SP_REGNUM; | |
1075 | else | |
1076 | { | |
1077 | /* Somehow the stack pointer has been corrupted. | |
1078 | We can't return. */ | |
1079 | if (nios2_debug) | |
1080 | fprintf_unfiltered (gdb_stdlog, "<can't reach cfa> }\n"); | |
1081 | return 0; | |
1082 | } | |
1083 | ||
1084 | if (cache->reg_value[base_reg].offset == 0 | |
1085 | || cache->reg_saved[NIOS2_RA_REGNUM].basereg != NIOS2_SP_REGNUM | |
1086 | || cache->reg_saved[cache->return_regnum].basereg != NIOS2_SP_REGNUM) | |
1087 | { | |
1088 | /* If the frame didn't adjust the stack, didn't save RA or | |
1089 | didn't save EA in an exception handler then it must either | |
1090 | be a leaf function (doesn't call any other functions) or it | |
1091 | can't return. If it has called another function then it | |
1092 | can't be a leaf, so set base == 0 to indicate that we can't | |
1093 | backtrace past it. */ | |
1094 | ||
1095 | if (!innermost) | |
1096 | { | |
1097 | /* If it isn't the innermost function then it can't be a | |
1098 | leaf, unless it was interrupted. Check whether RA for | |
1099 | this frame is the same as PC. If so then it probably | |
1100 | wasn't interrupted. */ | |
1101 | CORE_ADDR ra | |
1102 | = get_frame_register_unsigned (this_frame, NIOS2_RA_REGNUM); | |
1103 | ||
1104 | if (ra == current_pc) | |
1105 | { | |
1106 | if (nios2_debug) | |
1107 | fprintf_unfiltered | |
1108 | (gdb_stdlog, | |
1109 | "<noreturn ADJUST %s, r31@r%d+?>, r%d@r%d+?> }\n", | |
1110 | paddress (gdbarch, cache->reg_value[base_reg].offset), | |
1111 | cache->reg_saved[NIOS2_RA_REGNUM].basereg, | |
1112 | cache->return_regnum, | |
1113 | cache->reg_saved[cache->return_regnum].basereg); | |
1114 | return 0; | |
1115 | } | |
1116 | } | |
1117 | } | |
1118 | ||
1119 | /* Get the value of whichever register we are using for the | |
1120 | base. */ | |
1121 | cache->base = get_frame_register_unsigned (this_frame, base_reg); | |
1122 | ||
1123 | /* What was the value of SP at the start of this function (or just | |
1124 | after the stack switch). */ | |
1125 | frame_high = cache->base - cache->reg_value[base_reg].offset; | |
1126 | ||
1127 | /* Adjust all the saved registers such that they contain addresses | |
1128 | instead of offsets. */ | |
1129 | for (i = 0; i < NIOS2_NUM_REGS; i++) | |
1130 | if (cache->reg_saved[i].basereg == NIOS2_SP_REGNUM) | |
1131 | { | |
1132 | cache->reg_saved[i].basereg = NIOS2_Z_REGNUM; | |
1133 | cache->reg_saved[i].addr += frame_high; | |
1134 | } | |
1135 | ||
1136 | for (i = 0; i < NIOS2_NUM_REGS; i++) | |
1137 | if (cache->reg_saved[i].basereg == NIOS2_GP_REGNUM) | |
1138 | { | |
1139 | CORE_ADDR gp = get_frame_register_unsigned (this_frame, | |
1140 | NIOS2_GP_REGNUM); | |
1141 | ||
1142 | for ( ; i < NIOS2_NUM_REGS; i++) | |
1143 | if (cache->reg_saved[i].basereg == NIOS2_GP_REGNUM) | |
1144 | { | |
1145 | cache->reg_saved[i].basereg = NIOS2_Z_REGNUM; | |
1146 | cache->reg_saved[i].addr += gp; | |
1147 | } | |
1148 | } | |
1149 | ||
1150 | /* Work out what the value of SP was on the first instruction of | |
1151 | this function. If we didn't switch stacks then this can be | |
1152 | trivially computed from the base address. */ | |
1153 | if (cache->reg_saved[NIOS2_SP_REGNUM].basereg == NIOS2_Z_REGNUM) | |
1154 | cache->cfa | |
1155 | = read_memory_unsigned_integer (cache->reg_saved[NIOS2_SP_REGNUM].addr, | |
1156 | 4, byte_order); | |
1157 | else | |
1158 | cache->cfa = frame_high; | |
1159 | ||
1160 | /* Exception handlers restore ESTATUS into STATUS. */ | |
1161 | if (exception_handler) | |
1162 | { | |
1163 | cache->reg_saved[NIOS2_STATUS_REGNUM] | |
1164 | = cache->reg_saved[NIOS2_ESTATUS_REGNUM]; | |
1165 | cache->reg_saved[NIOS2_ESTATUS_REGNUM].basereg = -1; | |
1166 | } | |
1167 | ||
1168 | if (nios2_debug) | |
1169 | fprintf_unfiltered (gdb_stdlog, "cfa=%s }\n", | |
1170 | paddress (gdbarch, cache->cfa)); | |
1171 | ||
1172 | return prologue_end; | |
1173 | } | |
1174 | ||
1175 | /* Implement the skip_prologue gdbarch hook. */ | |
1176 | ||
1177 | static CORE_ADDR | |
1178 | nios2_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc) | |
1179 | { | |
a1217d97 SL |
1180 | CORE_ADDR func_addr; |
1181 | ||
1182 | struct nios2_unwind_cache cache; | |
1183 | ||
1184 | /* See if we can determine the end of the prologue via the symbol | |
1185 | table. If so, then return either PC, or the PC after the | |
1186 | prologue, whichever is greater. */ | |
1187 | if (find_pc_partial_function (start_pc, NULL, &func_addr, NULL)) | |
1188 | { | |
1189 | CORE_ADDR post_prologue_pc | |
1190 | = skip_prologue_using_sal (gdbarch, func_addr); | |
1191 | ||
1192 | if (post_prologue_pc != 0) | |
1193 | return max (start_pc, post_prologue_pc); | |
1194 | } | |
1195 | ||
1196 | /* Prologue analysis does the rest.... */ | |
1197 | nios2_init_cache (&cache, start_pc); | |
1198 | return nios2_analyze_prologue (gdbarch, start_pc, start_pc, &cache, NULL); | |
1199 | } | |
1200 | ||
b73c49b7 SL |
1201 | /* Implement the breakpoint_from_pc gdbarch hook. |
1202 | ||
1203 | The Nios II ABI for Linux says: "Userspace programs should not use | |
1204 | the break instruction and userspace debuggers should not insert | |
1205 | one." and "Userspace breakpoints are accomplished using the trap | |
1206 | instruction with immediate operand 31 (all ones)." | |
1207 | ||
1208 | So, we use "trap 31" consistently as the breakpoint on bare-metal | |
1209 | as well as Linux targets. */ | |
a1217d97 SL |
1210 | |
1211 | static const gdb_byte* | |
1212 | nios2_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *bp_addr, | |
1213 | int *bp_size) | |
1214 | { | |
a1217d97 | 1215 | enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch); |
d53c26c7 SL |
1216 | unsigned long mach = gdbarch_bfd_arch_info (gdbarch)->mach; |
1217 | ||
b73c49b7 SL |
1218 | /* R1 trap encoding: |
1219 | ((0x1d << 17) | (0x2d << 11) | (0x1f << 6) | (0x3a << 0)) | |
1220 | 0x003b6ffa */ | |
1221 | static const gdb_byte r1_breakpoint_le[] = {0xfa, 0x6f, 0x3b, 0x0}; | |
1222 | static const gdb_byte r1_breakpoint_be[] = {0x0, 0x3b, 0x6f, 0xfa}; | |
d53c26c7 SL |
1223 | *bp_size = NIOS2_OPCODE_SIZE; |
1224 | if (byte_order_for_code == BFD_ENDIAN_BIG) | |
1225 | return r1_breakpoint_be; | |
a1217d97 | 1226 | else |
d53c26c7 | 1227 | return r1_breakpoint_le; |
a1217d97 SL |
1228 | } |
1229 | ||
1230 | /* Implement the print_insn gdbarch method. */ | |
1231 | ||
1232 | static int | |
1233 | nios2_print_insn (bfd_vma memaddr, disassemble_info *info) | |
1234 | { | |
1235 | if (info->endian == BFD_ENDIAN_BIG) | |
1236 | return print_insn_big_nios2 (memaddr, info); | |
1237 | else | |
1238 | return print_insn_little_nios2 (memaddr, info); | |
1239 | } | |
1240 | ||
1241 | ||
1242 | /* Implement the frame_align gdbarch method. */ | |
1243 | ||
1244 | static CORE_ADDR | |
1245 | nios2_frame_align (struct gdbarch *gdbarch, CORE_ADDR addr) | |
1246 | { | |
1247 | return align_down (addr, 4); | |
1248 | } | |
1249 | ||
1250 | ||
1251 | /* Implement the return_value gdbarch method. */ | |
1252 | ||
1253 | static enum return_value_convention | |
1254 | nios2_return_value (struct gdbarch *gdbarch, struct value *function, | |
1255 | struct type *type, struct regcache *regcache, | |
1256 | gdb_byte *readbuf, const gdb_byte *writebuf) | |
1257 | { | |
1258 | if (TYPE_LENGTH (type) > 8) | |
1259 | return RETURN_VALUE_STRUCT_CONVENTION; | |
1260 | ||
1261 | if (readbuf) | |
1262 | nios2_extract_return_value (gdbarch, type, regcache, readbuf); | |
1263 | if (writebuf) | |
1264 | nios2_store_return_value (gdbarch, type, regcache, writebuf); | |
1265 | ||
1266 | return RETURN_VALUE_REGISTER_CONVENTION; | |
1267 | } | |
1268 | ||
1269 | /* Implement the dummy_id gdbarch method. */ | |
1270 | ||
1271 | static struct frame_id | |
1272 | nios2_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame) | |
1273 | { | |
1274 | return frame_id_build | |
1275 | (get_frame_register_unsigned (this_frame, NIOS2_SP_REGNUM), | |
1276 | get_frame_pc (this_frame)); | |
1277 | } | |
1278 | ||
1279 | /* Implement the push_dummy_call gdbarch method. */ | |
1280 | ||
1281 | static CORE_ADDR | |
1282 | nios2_push_dummy_call (struct gdbarch *gdbarch, struct value *function, | |
1283 | struct regcache *regcache, CORE_ADDR bp_addr, | |
1284 | int nargs, struct value **args, CORE_ADDR sp, | |
1285 | int struct_return, CORE_ADDR struct_addr) | |
1286 | { | |
1287 | int argreg; | |
1288 | int float_argreg; | |
1289 | int argnum; | |
1290 | int len = 0; | |
1291 | int stack_offset = 0; | |
1292 | CORE_ADDR func_addr = find_function_addr (function, NULL); | |
1293 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
1294 | ||
1295 | /* Set the return address register to point to the entry point of | |
1296 | the program, where a breakpoint lies in wait. */ | |
1297 | regcache_cooked_write_signed (regcache, NIOS2_RA_REGNUM, bp_addr); | |
1298 | ||
1299 | /* Now make space on the stack for the args. */ | |
1300 | for (argnum = 0; argnum < nargs; argnum++) | |
1301 | len += align_up (TYPE_LENGTH (value_type (args[argnum])), 4); | |
1302 | sp -= len; | |
1303 | ||
1304 | /* Initialize the register pointer. */ | |
1305 | argreg = NIOS2_FIRST_ARGREG; | |
1306 | ||
1307 | /* The struct_return pointer occupies the first parameter-passing | |
1308 | register. */ | |
1309 | if (struct_return) | |
1310 | regcache_cooked_write_unsigned (regcache, argreg++, struct_addr); | |
1311 | ||
1312 | /* Now load as many as possible of the first arguments into | |
1313 | registers, and push the rest onto the stack. Loop through args | |
1314 | from first to last. */ | |
1315 | for (argnum = 0; argnum < nargs; argnum++) | |
1316 | { | |
1317 | const gdb_byte *val; | |
1318 | gdb_byte valbuf[MAX_REGISTER_SIZE]; | |
1319 | struct value *arg = args[argnum]; | |
1320 | struct type *arg_type = check_typedef (value_type (arg)); | |
1321 | int len = TYPE_LENGTH (arg_type); | |
1322 | enum type_code typecode = TYPE_CODE (arg_type); | |
1323 | ||
1324 | val = value_contents (arg); | |
1325 | ||
1326 | /* Copy the argument to general registers or the stack in | |
1327 | register-sized pieces. Large arguments are split between | |
1328 | registers and stack. */ | |
1329 | while (len > 0) | |
1330 | { | |
1331 | int partial_len = (len < 4 ? len : 4); | |
1332 | ||
1333 | if (argreg <= NIOS2_LAST_ARGREG) | |
1334 | { | |
1335 | /* The argument is being passed in a register. */ | |
1336 | CORE_ADDR regval = extract_unsigned_integer (val, partial_len, | |
1337 | byte_order); | |
1338 | ||
1339 | regcache_cooked_write_unsigned (regcache, argreg, regval); | |
1340 | argreg++; | |
1341 | } | |
1342 | else | |
1343 | { | |
1344 | /* The argument is being passed on the stack. */ | |
1345 | CORE_ADDR addr = sp + stack_offset; | |
1346 | ||
1347 | write_memory (addr, val, partial_len); | |
1348 | stack_offset += align_up (partial_len, 4); | |
1349 | } | |
1350 | ||
1351 | len -= partial_len; | |
1352 | val += partial_len; | |
1353 | } | |
1354 | } | |
1355 | ||
1356 | regcache_cooked_write_signed (regcache, NIOS2_SP_REGNUM, sp); | |
1357 | ||
1358 | /* Return adjusted stack pointer. */ | |
1359 | return sp; | |
1360 | } | |
1361 | ||
1362 | /* Implement the unwind_pc gdbarch method. */ | |
1363 | ||
1364 | static CORE_ADDR | |
1365 | nios2_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame) | |
1366 | { | |
1367 | gdb_byte buf[4]; | |
1368 | ||
1369 | frame_unwind_register (next_frame, NIOS2_PC_REGNUM, buf); | |
1370 | return extract_typed_address (buf, builtin_type (gdbarch)->builtin_func_ptr); | |
1371 | } | |
1372 | ||
1373 | /* Implement the unwind_sp gdbarch method. */ | |
1374 | ||
1375 | static CORE_ADDR | |
1376 | nios2_unwind_sp (struct gdbarch *gdbarch, struct frame_info *this_frame) | |
1377 | { | |
1378 | return frame_unwind_register_unsigned (this_frame, NIOS2_SP_REGNUM); | |
1379 | } | |
1380 | ||
1381 | /* Use prologue analysis to fill in the register cache | |
1382 | *THIS_PROLOGUE_CACHE for THIS_FRAME. This function initializes | |
1383 | *THIS_PROLOGUE_CACHE first. */ | |
1384 | ||
1385 | static struct nios2_unwind_cache * | |
1386 | nios2_frame_unwind_cache (struct frame_info *this_frame, | |
1387 | void **this_prologue_cache) | |
1388 | { | |
1389 | struct gdbarch *gdbarch = get_frame_arch (this_frame); | |
1390 | CORE_ADDR current_pc; | |
1391 | struct nios2_unwind_cache *cache; | |
1392 | int i; | |
1393 | ||
1394 | if (*this_prologue_cache) | |
1395 | return *this_prologue_cache; | |
1396 | ||
1397 | cache = FRAME_OBSTACK_ZALLOC (struct nios2_unwind_cache); | |
1398 | *this_prologue_cache = cache; | |
1399 | ||
1400 | /* Zero all fields. */ | |
1401 | nios2_init_cache (cache, get_frame_func (this_frame)); | |
1402 | ||
1403 | /* Prologue analysis does the rest... */ | |
1404 | current_pc = get_frame_pc (this_frame); | |
1405 | if (cache->pc != 0) | |
1406 | nios2_analyze_prologue (gdbarch, cache->pc, current_pc, cache, this_frame); | |
1407 | ||
1408 | return cache; | |
1409 | } | |
1410 | ||
1411 | /* Implement the this_id function for the normal unwinder. */ | |
1412 | ||
1413 | static void | |
1414 | nios2_frame_this_id (struct frame_info *this_frame, void **this_cache, | |
1415 | struct frame_id *this_id) | |
1416 | { | |
1417 | struct nios2_unwind_cache *cache = | |
1418 | nios2_frame_unwind_cache (this_frame, this_cache); | |
1419 | ||
1420 | /* This marks the outermost frame. */ | |
1421 | if (cache->base == 0) | |
1422 | return; | |
1423 | ||
1424 | *this_id = frame_id_build (cache->cfa, cache->pc); | |
1425 | } | |
1426 | ||
1427 | /* Implement the prev_register function for the normal unwinder. */ | |
1428 | ||
1429 | static struct value * | |
1430 | nios2_frame_prev_register (struct frame_info *this_frame, void **this_cache, | |
1431 | int regnum) | |
1432 | { | |
1433 | struct nios2_unwind_cache *cache = | |
1434 | nios2_frame_unwind_cache (this_frame, this_cache); | |
1435 | ||
1436 | gdb_assert (regnum >= 0 && regnum < NIOS2_NUM_REGS); | |
1437 | ||
1438 | /* The PC of the previous frame is stored in the RA register of | |
1439 | the current frame. Frob regnum so that we pull the value from | |
1440 | the correct place. */ | |
1441 | if (regnum == NIOS2_PC_REGNUM) | |
1442 | regnum = cache->return_regnum; | |
1443 | ||
1444 | if (regnum == NIOS2_SP_REGNUM && cache->cfa) | |
1445 | return frame_unwind_got_constant (this_frame, regnum, cache->cfa); | |
1446 | ||
1447 | /* If we've worked out where a register is stored then load it from | |
1448 | there. */ | |
1449 | if (cache->reg_saved[regnum].basereg == NIOS2_Z_REGNUM) | |
1450 | return frame_unwind_got_memory (this_frame, regnum, | |
1451 | cache->reg_saved[regnum].addr); | |
1452 | ||
1453 | return frame_unwind_got_register (this_frame, regnum, regnum); | |
1454 | } | |
1455 | ||
1456 | /* Implement the this_base, this_locals, and this_args hooks | |
1457 | for the normal unwinder. */ | |
1458 | ||
1459 | static CORE_ADDR | |
1460 | nios2_frame_base_address (struct frame_info *this_frame, void **this_cache) | |
1461 | { | |
1462 | struct nios2_unwind_cache *info | |
1463 | = nios2_frame_unwind_cache (this_frame, this_cache); | |
1464 | ||
1465 | return info->base; | |
1466 | } | |
1467 | ||
1468 | /* Data structures for the normal prologue-analysis-based | |
1469 | unwinder. */ | |
1470 | ||
1471 | static const struct frame_unwind nios2_frame_unwind = | |
1472 | { | |
1473 | NORMAL_FRAME, | |
1474 | default_frame_unwind_stop_reason, | |
1475 | nios2_frame_this_id, | |
1476 | nios2_frame_prev_register, | |
1477 | NULL, | |
1478 | default_frame_sniffer | |
1479 | }; | |
1480 | ||
1481 | static const struct frame_base nios2_frame_base = | |
1482 | { | |
1483 | &nios2_frame_unwind, | |
1484 | nios2_frame_base_address, | |
1485 | nios2_frame_base_address, | |
1486 | nios2_frame_base_address | |
1487 | }; | |
1488 | ||
1489 | /* Fill in the register cache *THIS_CACHE for THIS_FRAME for use | |
1490 | in the stub unwinder. */ | |
1491 | ||
1492 | static struct trad_frame_cache * | |
1493 | nios2_stub_frame_cache (struct frame_info *this_frame, void **this_cache) | |
1494 | { | |
1495 | CORE_ADDR pc; | |
1496 | CORE_ADDR start_addr; | |
1497 | CORE_ADDR stack_addr; | |
1498 | struct trad_frame_cache *this_trad_cache; | |
1499 | struct gdbarch *gdbarch = get_frame_arch (this_frame); | |
1500 | int num_regs = gdbarch_num_regs (gdbarch); | |
1501 | ||
1502 | if (*this_cache != NULL) | |
1503 | return *this_cache; | |
1504 | this_trad_cache = trad_frame_cache_zalloc (this_frame); | |
1505 | *this_cache = this_trad_cache; | |
1506 | ||
1507 | /* The return address is in the link register. */ | |
1508 | trad_frame_set_reg_realreg (this_trad_cache, | |
1509 | gdbarch_pc_regnum (gdbarch), | |
1510 | NIOS2_RA_REGNUM); | |
1511 | ||
1512 | /* Frame ID, since it's a frameless / stackless function, no stack | |
1513 | space is allocated and SP on entry is the current SP. */ | |
1514 | pc = get_frame_pc (this_frame); | |
1515 | find_pc_partial_function (pc, NULL, &start_addr, NULL); | |
1516 | stack_addr = get_frame_register_unsigned (this_frame, NIOS2_SP_REGNUM); | |
1517 | trad_frame_set_id (this_trad_cache, frame_id_build (start_addr, stack_addr)); | |
1518 | /* Assume that the frame's base is the same as the stack pointer. */ | |
1519 | trad_frame_set_this_base (this_trad_cache, stack_addr); | |
1520 | ||
1521 | return this_trad_cache; | |
1522 | } | |
1523 | ||
1524 | /* Implement the this_id function for the stub unwinder. */ | |
1525 | ||
1526 | static void | |
1527 | nios2_stub_frame_this_id (struct frame_info *this_frame, void **this_cache, | |
1528 | struct frame_id *this_id) | |
1529 | { | |
1530 | struct trad_frame_cache *this_trad_cache | |
1531 | = nios2_stub_frame_cache (this_frame, this_cache); | |
1532 | ||
1533 | trad_frame_get_id (this_trad_cache, this_id); | |
1534 | } | |
1535 | ||
1536 | /* Implement the prev_register function for the stub unwinder. */ | |
1537 | ||
1538 | static struct value * | |
1539 | nios2_stub_frame_prev_register (struct frame_info *this_frame, | |
1540 | void **this_cache, int regnum) | |
1541 | { | |
1542 | struct trad_frame_cache *this_trad_cache | |
1543 | = nios2_stub_frame_cache (this_frame, this_cache); | |
1544 | ||
1545 | return trad_frame_get_register (this_trad_cache, this_frame, regnum); | |
1546 | } | |
1547 | ||
1548 | /* Implement the sniffer function for the stub unwinder. | |
1549 | This unwinder is used for cases where the normal | |
1550 | prologue-analysis-based unwinder can't work, | |
1551 | such as PLT stubs. */ | |
1552 | ||
1553 | static int | |
1554 | nios2_stub_frame_sniffer (const struct frame_unwind *self, | |
1555 | struct frame_info *this_frame, void **cache) | |
1556 | { | |
1557 | gdb_byte dummy[4]; | |
1558 | struct obj_section *s; | |
1559 | CORE_ADDR pc = get_frame_address_in_block (this_frame); | |
1560 | ||
1561 | /* Use the stub unwinder for unreadable code. */ | |
1562 | if (target_read_memory (get_frame_pc (this_frame), dummy, 4) != 0) | |
1563 | return 1; | |
1564 | ||
3e5d3a5a | 1565 | if (in_plt_section (pc)) |
a1217d97 SL |
1566 | return 1; |
1567 | ||
1568 | return 0; | |
1569 | } | |
1570 | ||
a1217d97 SL |
1571 | /* Define the data structures for the stub unwinder. */ |
1572 | ||
1573 | static const struct frame_unwind nios2_stub_frame_unwind = | |
1574 | { | |
1575 | NORMAL_FRAME, | |
1576 | default_frame_unwind_stop_reason, | |
1577 | nios2_stub_frame_this_id, | |
1578 | nios2_stub_frame_prev_register, | |
1579 | NULL, | |
1580 | nios2_stub_frame_sniffer | |
1581 | }; | |
1582 | ||
a1217d97 | 1583 | |
a1217d97 SL |
1584 | |
1585 | /* Determine where to set a single step breakpoint while considering | |
1586 | branch prediction. */ | |
1587 | ||
1588 | static CORE_ADDR | |
1589 | nios2_get_next_pc (struct frame_info *frame, CORE_ADDR pc) | |
1590 | { | |
1591 | struct gdbarch *gdbarch = get_frame_arch (frame); | |
1592 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
d53c26c7 SL |
1593 | unsigned long mach = gdbarch_bfd_arch_info (gdbarch)->mach; |
1594 | unsigned int insn; | |
1595 | const struct nios2_opcode *op = nios2_fetch_insn (gdbarch, pc, &insn); | |
a1217d97 SL |
1596 | int ra; |
1597 | int rb; | |
d53c26c7 SL |
1598 | int imm; |
1599 | unsigned int uimm; | |
1600 | int wb, ret; | |
1601 | enum branch_condition cond; | |
1602 | ||
1603 | /* Do something stupid if we can't disassemble the insn at pc. */ | |
1604 | if (op == NULL) | |
1605 | return pc + NIOS2_OPCODE_SIZE; | |
1606 | ||
1607 | if (nios2_match_branch (insn, op, mach, &ra, &rb, &imm, &cond)) | |
a1217d97 | 1608 | { |
d53c26c7 SL |
1609 | int ras = get_frame_register_signed (frame, ra); |
1610 | int rbs = get_frame_register_signed (frame, rb); | |
1611 | unsigned int rau = get_frame_register_unsigned (frame, ra); | |
1612 | unsigned int rbu = get_frame_register_unsigned (frame, rb); | |
a1217d97 | 1613 | |
d53c26c7 SL |
1614 | pc += op->size; |
1615 | switch (cond) | |
a1217d97 | 1616 | { |
d53c26c7 SL |
1617 | case branch_none: |
1618 | pc += imm; | |
1619 | break; | |
1620 | case branch_eq: | |
1621 | if (ras == rbs) | |
1622 | pc += imm; | |
1623 | break; | |
1624 | case branch_ne: | |
1625 | if (ras != rbs) | |
1626 | pc += imm; | |
1627 | break; | |
1628 | case branch_ge: | |
1629 | if (ras >= rbs) | |
1630 | pc += imm; | |
1631 | break; | |
1632 | case branch_geu: | |
1633 | if (rau >= rbu) | |
1634 | pc += imm; | |
1635 | break; | |
1636 | case branch_lt: | |
1637 | if (ras < rbs) | |
1638 | pc += imm; | |
1639 | break; | |
1640 | case branch_ltu: | |
1641 | if (rau < rbu) | |
1642 | pc += imm; | |
a1217d97 | 1643 | break; |
a1217d97 SL |
1644 | default: |
1645 | break; | |
1646 | } | |
a1217d97 | 1647 | } |
d53c26c7 SL |
1648 | |
1649 | else if (nios2_match_jmpi (insn, op, mach, &uimm) | |
1650 | || nios2_match_calli (insn, op, mach, &uimm)) | |
1651 | pc = (pc & 0xf0000000) | uimm; | |
1652 | ||
1653 | else if (nios2_match_jmpr (insn, op, mach, &ra) | |
1654 | || nios2_match_callr (insn, op, mach, &ra)) | |
1655 | pc = get_frame_register_unsigned (frame, ra); | |
1656 | ||
1657 | else if (nios2_match_trap (insn, op, mach, &uimm)) | |
1658 | { | |
1659 | if (tdep->syscall_next_pc != NULL) | |
1660 | return tdep->syscall_next_pc (frame); | |
1661 | } | |
1662 | ||
1663 | else | |
1664 | pc += op->size; | |
1665 | ||
a1217d97 SL |
1666 | return pc; |
1667 | } | |
1668 | ||
1669 | /* Implement the software_single_step gdbarch method. */ | |
1670 | ||
1671 | static int | |
1672 | nios2_software_single_step (struct frame_info *frame) | |
1673 | { | |
1674 | struct gdbarch *gdbarch = get_frame_arch (frame); | |
1675 | struct address_space *aspace = get_frame_address_space (frame); | |
1676 | CORE_ADDR next_pc = nios2_get_next_pc (frame, get_frame_pc (frame)); | |
1677 | ||
1678 | insert_single_step_breakpoint (gdbarch, aspace, next_pc); | |
1679 | ||
1680 | return 1; | |
1681 | } | |
1682 | ||
1683 | /* Implement the get_longjump_target gdbarch method. */ | |
1684 | ||
1685 | static int | |
1686 | nios2_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc) | |
1687 | { | |
1688 | struct gdbarch *gdbarch = get_frame_arch (frame); | |
1689 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
1690 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
1691 | CORE_ADDR jb_addr = get_frame_register_unsigned (frame, NIOS2_R4_REGNUM); | |
1692 | gdb_byte buf[4]; | |
1693 | ||
1694 | if (target_read_memory (jb_addr + (tdep->jb_pc * 4), buf, 4)) | |
1695 | return 0; | |
1696 | ||
1697 | *pc = extract_unsigned_integer (buf, 4, byte_order); | |
1698 | return 1; | |
1699 | } | |
1700 | ||
1701 | /* Initialize the Nios II gdbarch. */ | |
1702 | ||
1703 | static struct gdbarch * | |
1704 | nios2_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) | |
1705 | { | |
1706 | struct gdbarch *gdbarch; | |
1707 | struct gdbarch_tdep *tdep; | |
1708 | int register_bytes, i; | |
1709 | struct tdesc_arch_data *tdesc_data = NULL; | |
1710 | const struct target_desc *tdesc = info.target_desc; | |
1711 | ||
1712 | if (!tdesc_has_registers (tdesc)) | |
1713 | /* Pick a default target description. */ | |
1714 | tdesc = tdesc_nios2; | |
1715 | ||
1716 | /* Check any target description for validity. */ | |
1717 | if (tdesc_has_registers (tdesc)) | |
1718 | { | |
1719 | const struct tdesc_feature *feature; | |
1720 | int valid_p; | |
1721 | ||
1722 | feature = tdesc_find_feature (tdesc, "org.gnu.gdb.nios2.cpu"); | |
1723 | if (feature == NULL) | |
1724 | return NULL; | |
1725 | ||
1726 | tdesc_data = tdesc_data_alloc (); | |
1727 | ||
1728 | valid_p = 1; | |
1729 | ||
1730 | for (i = 0; i < NIOS2_NUM_REGS; i++) | |
1731 | valid_p &= tdesc_numbered_register (feature, tdesc_data, i, | |
1732 | nios2_reg_names[i]); | |
1733 | ||
1734 | if (!valid_p) | |
1735 | { | |
1736 | tdesc_data_cleanup (tdesc_data); | |
1737 | return NULL; | |
1738 | } | |
1739 | } | |
1740 | ||
1741 | /* Find a candidate among the list of pre-declared architectures. */ | |
1742 | arches = gdbarch_list_lookup_by_info (arches, &info); | |
1743 | if (arches != NULL) | |
1744 | return arches->gdbarch; | |
1745 | ||
1746 | /* None found, create a new architecture from the information | |
1747 | provided. */ | |
1748 | tdep = xcalloc (1, sizeof (struct gdbarch_tdep)); | |
1749 | gdbarch = gdbarch_alloc (&info, tdep); | |
1750 | ||
1751 | /* longjmp support not enabled by default. */ | |
1752 | tdep->jb_pc = -1; | |
1753 | ||
1754 | /* Data type sizes. */ | |
1755 | set_gdbarch_ptr_bit (gdbarch, 32); | |
1756 | set_gdbarch_addr_bit (gdbarch, 32); | |
1757 | set_gdbarch_short_bit (gdbarch, 16); | |
1758 | set_gdbarch_int_bit (gdbarch, 32); | |
1759 | set_gdbarch_long_bit (gdbarch, 32); | |
1760 | set_gdbarch_long_long_bit (gdbarch, 64); | |
1761 | set_gdbarch_float_bit (gdbarch, 32); | |
1762 | set_gdbarch_double_bit (gdbarch, 64); | |
1763 | ||
1764 | set_gdbarch_float_format (gdbarch, floatformats_ieee_single); | |
1765 | set_gdbarch_double_format (gdbarch, floatformats_ieee_double); | |
1766 | ||
1767 | /* The register set. */ | |
1768 | set_gdbarch_num_regs (gdbarch, NIOS2_NUM_REGS); | |
1769 | set_gdbarch_sp_regnum (gdbarch, NIOS2_SP_REGNUM); | |
1770 | set_gdbarch_pc_regnum (gdbarch, NIOS2_PC_REGNUM); /* Pseudo register PC */ | |
1771 | ||
1772 | set_gdbarch_register_name (gdbarch, nios2_register_name); | |
1773 | set_gdbarch_register_type (gdbarch, nios2_register_type); | |
1774 | ||
1775 | /* Provide register mappings for stabs and dwarf2. */ | |
1776 | set_gdbarch_stab_reg_to_regnum (gdbarch, nios2_dwarf_reg_to_regnum); | |
1777 | set_gdbarch_dwarf2_reg_to_regnum (gdbarch, nios2_dwarf_reg_to_regnum); | |
1778 | ||
1779 | set_gdbarch_inner_than (gdbarch, core_addr_lessthan); | |
1780 | ||
1781 | /* Call dummy code. */ | |
1782 | set_gdbarch_frame_align (gdbarch, nios2_frame_align); | |
1783 | ||
1784 | set_gdbarch_return_value (gdbarch, nios2_return_value); | |
1785 | ||
1786 | set_gdbarch_skip_prologue (gdbarch, nios2_skip_prologue); | |
c9cf6e20 | 1787 | set_gdbarch_stack_frame_destroyed_p (gdbarch, nios2_stack_frame_destroyed_p); |
a1217d97 SL |
1788 | set_gdbarch_breakpoint_from_pc (gdbarch, nios2_breakpoint_from_pc); |
1789 | ||
1790 | set_gdbarch_dummy_id (gdbarch, nios2_dummy_id); | |
1791 | set_gdbarch_unwind_pc (gdbarch, nios2_unwind_pc); | |
1792 | set_gdbarch_unwind_sp (gdbarch, nios2_unwind_sp); | |
1793 | ||
1794 | /* The dwarf2 unwinder will normally produce the best results if | |
1795 | the debug information is available, so register it first. */ | |
1796 | dwarf2_append_unwinders (gdbarch); | |
1797 | frame_unwind_append_unwinder (gdbarch, &nios2_stub_frame_unwind); | |
1798 | frame_unwind_append_unwinder (gdbarch, &nios2_frame_unwind); | |
1799 | ||
1800 | /* Single stepping. */ | |
1801 | set_gdbarch_software_single_step (gdbarch, nios2_software_single_step); | |
1802 | ||
1803 | /* Hook in ABI-specific overrides, if they have been registered. */ | |
1804 | gdbarch_init_osabi (info, gdbarch); | |
1805 | ||
1806 | if (tdep->jb_pc >= 0) | |
1807 | set_gdbarch_get_longjmp_target (gdbarch, nios2_get_longjmp_target); | |
1808 | ||
1809 | frame_base_set_default (gdbarch, &nios2_frame_base); | |
1810 | ||
1811 | set_gdbarch_print_insn (gdbarch, nios2_print_insn); | |
1812 | ||
1813 | /* Enable inferior call support. */ | |
1814 | set_gdbarch_push_dummy_call (gdbarch, nios2_push_dummy_call); | |
1815 | ||
1816 | if (tdesc_data) | |
1817 | tdesc_use_registers (gdbarch, tdesc, tdesc_data); | |
1818 | ||
1819 | return gdbarch; | |
1820 | } | |
1821 | ||
1822 | extern initialize_file_ftype _initialize_nios2_tdep; /* -Wmissing-prototypes */ | |
1823 | ||
1824 | void | |
1825 | _initialize_nios2_tdep (void) | |
1826 | { | |
1827 | gdbarch_register (bfd_arch_nios2, nios2_gdbarch_init, NULL); | |
1828 | initialize_tdesc_nios2 (); | |
1829 | ||
1830 | /* Allow debugging this file's internals. */ | |
1831 | add_setshow_boolean_cmd ("nios2", class_maintenance, &nios2_debug, | |
1832 | _("Set Nios II debugging."), | |
1833 | _("Show Nios II debugging."), | |
1834 | _("When on, Nios II specific debugging is enabled."), | |
1835 | NULL, | |
1836 | NULL, | |
1837 | &setdebuglist, &showdebuglist); | |
1838 | } |