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c906108c SS |
1 | /* Target-dependent code for the ALPHA architecture, for GDB, the GNU Debugger. |
2 | Copyright 1993, 94, 95, 96, 97, 1998 Free Software Foundation, Inc. | |
3 | ||
c5aa993b | 4 | This file is part of GDB. |
c906108c | 5 | |
c5aa993b JM |
6 | This program is free software; you can redistribute it and/or modify |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2 of the License, or | |
9 | (at your option) any later version. | |
c906108c | 10 | |
c5aa993b JM |
11 | This program is distributed in the hope that it will be useful, |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
c906108c | 15 | |
c5aa993b JM |
16 | You should have received a copy of the GNU General Public License |
17 | along with this program; if not, write to the Free Software | |
18 | Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | Boston, MA 02111-1307, USA. */ | |
c906108c SS |
20 | |
21 | #include "defs.h" | |
22 | #include "frame.h" | |
23 | #include "inferior.h" | |
24 | #include "symtab.h" | |
25 | #include "value.h" | |
26 | #include "gdbcmd.h" | |
27 | #include "gdbcore.h" | |
28 | #include "dis-asm.h" | |
29 | #include "symfile.h" | |
30 | #include "objfiles.h" | |
31 | #include "gdb_string.h" | |
32 | ||
33 | /* FIXME: Some of this code should perhaps be merged with mips-tdep.c. */ | |
34 | ||
35 | /* Prototypes for local functions. */ | |
36 | ||
37 | static alpha_extra_func_info_t push_sigtramp_desc PARAMS ((CORE_ADDR low_addr)); | |
38 | ||
39 | static CORE_ADDR read_next_frame_reg PARAMS ((struct frame_info *, int)); | |
40 | ||
41 | static CORE_ADDR heuristic_proc_start PARAMS ((CORE_ADDR)); | |
42 | ||
43 | static alpha_extra_func_info_t heuristic_proc_desc PARAMS ((CORE_ADDR, | |
44 | CORE_ADDR, | |
c5aa993b | 45 | struct frame_info *)); |
c906108c SS |
46 | |
47 | static alpha_extra_func_info_t find_proc_desc PARAMS ((CORE_ADDR, | |
48 | struct frame_info *)); | |
49 | ||
50 | #if 0 | |
51 | static int alpha_in_lenient_prologue PARAMS ((CORE_ADDR, CORE_ADDR)); | |
52 | #endif | |
53 | ||
54 | static void reinit_frame_cache_sfunc PARAMS ((char *, int, | |
55 | struct cmd_list_element *)); | |
56 | ||
57 | static CORE_ADDR after_prologue PARAMS ((CORE_ADDR pc, | |
58 | alpha_extra_func_info_t proc_desc)); | |
59 | ||
60 | static int alpha_in_prologue PARAMS ((CORE_ADDR pc, | |
c5aa993b | 61 | alpha_extra_func_info_t proc_desc)); |
c906108c | 62 | |
392a587b JM |
63 | static int alpha_about_to_return PARAMS ((CORE_ADDR pc)); |
64 | ||
65 | void _initialize_alpha_tdep PARAMS ((void)); | |
66 | ||
c906108c SS |
67 | /* Heuristic_proc_start may hunt through the text section for a long |
68 | time across a 2400 baud serial line. Allows the user to limit this | |
69 | search. */ | |
70 | static unsigned int heuristic_fence_post = 0; | |
c5aa993b | 71 | /* *INDENT-OFF* */ |
c906108c SS |
72 | /* Layout of a stack frame on the alpha: |
73 | ||
74 | | | | |
75 | pdr members: | 7th ... nth arg, | | |
76 | | `pushed' by caller. | | |
77 | | | | |
78 | ----------------|-------------------------------|<-- old_sp == vfp | |
79 | ^ ^ ^ ^ | | | |
80 | | | | | | | | |
81 | | |localoff | Copies of 1st .. 6th | | |
82 | | | | | | argument if necessary. | | |
83 | | | | v | | | |
84 | | | | --- |-------------------------------|<-- FRAME_LOCALS_ADDRESS | |
85 | | | | | | | |
86 | | | | | Locals and temporaries. | | |
87 | | | | | | | |
88 | | | | |-------------------------------| | |
89 | | | | | | | |
90 | |-fregoffset | Saved float registers. | | |
91 | | | | | F9 | | |
92 | | | | | . | | |
93 | | | | | . | | |
94 | | | | | F2 | | |
95 | | | v | | | |
96 | | | -------|-------------------------------| | |
97 | | | | | | |
98 | | | | Saved registers. | | |
99 | | | | S6 | | |
100 | |-regoffset | . | | |
101 | | | | . | | |
102 | | | | S0 | | |
103 | | | | pdr.pcreg | | |
104 | | v | | | |
105 | | ----------|-------------------------------| | |
106 | | | | | |
107 | frameoffset | Argument build area, gets | | |
108 | | | 7th ... nth arg for any | | |
109 | | | called procedure. | | |
110 | v | | | |
111 | -------------|-------------------------------|<-- sp | |
112 | | | | |
113 | */ | |
c5aa993b JM |
114 | /* *INDENT-ON* */ |
115 | ||
116 | ||
c906108c | 117 | |
c5aa993b | 118 | #define PROC_LOW_ADDR(proc) ((proc)->pdr.adr) /* least address */ |
b83266a0 SS |
119 | /* These next two fields are kind of being hijacked. I wonder if |
120 | iline is too small for the values it needs to hold, if GDB is | |
121 | running on a 32-bit host. */ | |
c5aa993b JM |
122 | #define PROC_HIGH_ADDR(proc) ((proc)->pdr.iline) /* upper address bound */ |
123 | #define PROC_DUMMY_FRAME(proc) ((proc)->pdr.cbLineOffset) /*CALL_DUMMY frame */ | |
c906108c SS |
124 | #define PROC_FRAME_OFFSET(proc) ((proc)->pdr.frameoffset) |
125 | #define PROC_FRAME_REG(proc) ((proc)->pdr.framereg) | |
126 | #define PROC_REG_MASK(proc) ((proc)->pdr.regmask) | |
127 | #define PROC_FREG_MASK(proc) ((proc)->pdr.fregmask) | |
128 | #define PROC_REG_OFFSET(proc) ((proc)->pdr.regoffset) | |
129 | #define PROC_FREG_OFFSET(proc) ((proc)->pdr.fregoffset) | |
130 | #define PROC_PC_REG(proc) ((proc)->pdr.pcreg) | |
131 | #define PROC_LOCALOFF(proc) ((proc)->pdr.localoff) | |
132 | #define PROC_SYMBOL(proc) (*(struct symbol**)&(proc)->pdr.isym) | |
133 | #define _PROC_MAGIC_ 0x0F0F0F0F | |
134 | #define PROC_DESC_IS_DUMMY(proc) ((proc)->pdr.isym == _PROC_MAGIC_) | |
135 | #define SET_PROC_DESC_IS_DUMMY(proc) ((proc)->pdr.isym = _PROC_MAGIC_) | |
136 | ||
137 | struct linked_proc_info | |
c5aa993b JM |
138 | { |
139 | struct alpha_extra_func_info info; | |
140 | struct linked_proc_info *next; | |
141 | } | |
142 | *linked_proc_desc_table = NULL; | |
c906108c | 143 | \f |
c5aa993b | 144 | |
c906108c SS |
145 | /* Under GNU/Linux, signal handler invocations can be identified by the |
146 | designated code sequence that is used to return from a signal | |
147 | handler. In particular, the return address of a signal handler | |
148 | points to the following sequence (the first instruction is quadword | |
149 | aligned): | |
150 | ||
c5aa993b JM |
151 | bis $30,$30,$16 |
152 | addq $31,0x67,$0 | |
153 | call_pal callsys | |
c906108c SS |
154 | |
155 | Each instruction has a unique encoding, so we simply attempt to | |
156 | match the instruction the pc is pointing to with any of the above | |
157 | instructions. If there is a hit, we know the offset to the start | |
158 | of the designated sequence and can then check whether we really are | |
159 | executing in a designated sequence. If not, -1 is returned, | |
160 | otherwise the offset from the start of the desingated sequence is | |
161 | returned. | |
162 | ||
163 | There is a slight chance of false hits: code could jump into the | |
164 | middle of the designated sequence, in which case there is no | |
165 | guarantee that we are in the middle of a sigreturn syscall. Don't | |
166 | think this will be a problem in praxis, though. | |
c5aa993b | 167 | */ |
c906108c | 168 | |
7a292a7a SS |
169 | #ifndef TM_LINUXALPHA_H |
170 | /* HACK: Provide a prototype when compiling this file for non | |
171 | linuxalpha targets. */ | |
172 | long alpha_linux_sigtramp_offset PARAMS ((CORE_ADDR pc)); | |
173 | #endif | |
c906108c | 174 | long |
7a292a7a SS |
175 | alpha_linux_sigtramp_offset (pc) |
176 | CORE_ADDR pc; | |
c906108c SS |
177 | { |
178 | unsigned int i[3], w; | |
179 | long off; | |
180 | ||
c5aa993b | 181 | if (read_memory_nobpt (pc, (char *) &w, 4) != 0) |
c906108c SS |
182 | return -1; |
183 | ||
184 | off = -1; | |
185 | switch (w) | |
186 | { | |
c5aa993b JM |
187 | case 0x47de0410: |
188 | off = 0; | |
189 | break; /* bis $30,$30,$16 */ | |
190 | case 0x43ecf400: | |
191 | off = 4; | |
192 | break; /* addq $31,0x67,$0 */ | |
193 | case 0x00000083: | |
194 | off = 8; | |
195 | break; /* call_pal callsys */ | |
196 | default: | |
197 | return -1; | |
c906108c SS |
198 | } |
199 | pc -= off; | |
200 | if (pc & 0x7) | |
201 | { | |
202 | /* designated sequence is not quadword aligned */ | |
203 | return -1; | |
204 | } | |
205 | ||
c5aa993b | 206 | if (read_memory_nobpt (pc, (char *) i, sizeof (i)) != 0) |
c906108c SS |
207 | return -1; |
208 | ||
209 | if (i[0] == 0x47de0410 && i[1] == 0x43ecf400 && i[2] == 0x00000083) | |
210 | return off; | |
211 | ||
212 | return -1; | |
213 | } | |
c906108c | 214 | \f |
c5aa993b | 215 | |
c906108c SS |
216 | /* Under OSF/1, the __sigtramp routine is frameless and has a frame |
217 | size of zero, but we are able to backtrace through it. */ | |
218 | CORE_ADDR | |
219 | alpha_osf_skip_sigtramp_frame (frame, pc) | |
220 | struct frame_info *frame; | |
221 | CORE_ADDR pc; | |
222 | { | |
223 | char *name; | |
c5aa993b | 224 | find_pc_partial_function (pc, &name, (CORE_ADDR *) NULL, (CORE_ADDR *) NULL); |
c906108c SS |
225 | if (IN_SIGTRAMP (pc, name)) |
226 | return frame->frame; | |
227 | else | |
228 | return 0; | |
229 | } | |
c906108c | 230 | \f |
c5aa993b | 231 | |
c906108c SS |
232 | /* Dynamically create a signal-handler caller procedure descriptor for |
233 | the signal-handler return code starting at address LOW_ADDR. The | |
234 | descriptor is added to the linked_proc_desc_table. */ | |
235 | ||
236 | static alpha_extra_func_info_t | |
237 | push_sigtramp_desc (low_addr) | |
238 | CORE_ADDR low_addr; | |
239 | { | |
240 | struct linked_proc_info *link; | |
241 | alpha_extra_func_info_t proc_desc; | |
242 | ||
243 | link = (struct linked_proc_info *) | |
244 | xmalloc (sizeof (struct linked_proc_info)); | |
245 | link->next = linked_proc_desc_table; | |
246 | linked_proc_desc_table = link; | |
247 | ||
248 | proc_desc = &link->info; | |
249 | ||
250 | proc_desc->numargs = 0; | |
c5aa993b JM |
251 | PROC_LOW_ADDR (proc_desc) = low_addr; |
252 | PROC_HIGH_ADDR (proc_desc) = low_addr + 3 * 4; | |
253 | PROC_DUMMY_FRAME (proc_desc) = 0; | |
254 | PROC_FRAME_OFFSET (proc_desc) = 0x298; /* sizeof(struct sigcontext_struct) */ | |
255 | PROC_FRAME_REG (proc_desc) = SP_REGNUM; | |
256 | PROC_REG_MASK (proc_desc) = 0xffff; | |
257 | PROC_FREG_MASK (proc_desc) = 0xffff; | |
258 | PROC_PC_REG (proc_desc) = 26; | |
259 | PROC_LOCALOFF (proc_desc) = 0; | |
c906108c SS |
260 | SET_PROC_DESC_IS_DYN_SIGTRAMP (proc_desc); |
261 | return (proc_desc); | |
262 | } | |
c906108c | 263 | \f |
c5aa993b | 264 | |
c906108c SS |
265 | /* Guaranteed to set frame->saved_regs to some values (it never leaves it |
266 | NULL). */ | |
267 | ||
268 | void | |
269 | alpha_find_saved_regs (frame) | |
270 | struct frame_info *frame; | |
271 | { | |
272 | int ireg; | |
273 | CORE_ADDR reg_position; | |
274 | unsigned long mask; | |
275 | alpha_extra_func_info_t proc_desc; | |
276 | int returnreg; | |
277 | ||
278 | frame_saved_regs_zalloc (frame); | |
279 | ||
280 | /* If it is the frame for __sigtramp, the saved registers are located | |
281 | in a sigcontext structure somewhere on the stack. __sigtramp | |
282 | passes a pointer to the sigcontext structure on the stack. | |
283 | If the stack layout for __sigtramp changes, or if sigcontext offsets | |
284 | change, we might have to update this code. */ | |
285 | #ifndef SIGFRAME_PC_OFF | |
286 | #define SIGFRAME_PC_OFF (2 * 8) | |
287 | #define SIGFRAME_REGSAVE_OFF (4 * 8) | |
288 | #define SIGFRAME_FPREGSAVE_OFF (SIGFRAME_REGSAVE_OFF + 32 * 8 + 8) | |
289 | #endif | |
290 | if (frame->signal_handler_caller) | |
291 | { | |
292 | CORE_ADDR sigcontext_addr; | |
293 | ||
294 | sigcontext_addr = SIGCONTEXT_ADDR (frame); | |
295 | for (ireg = 0; ireg < 32; ireg++) | |
296 | { | |
c5aa993b JM |
297 | reg_position = sigcontext_addr + SIGFRAME_REGSAVE_OFF + ireg * 8; |
298 | frame->saved_regs[ireg] = reg_position; | |
c906108c SS |
299 | } |
300 | for (ireg = 0; ireg < 32; ireg++) | |
301 | { | |
c5aa993b JM |
302 | reg_position = sigcontext_addr + SIGFRAME_FPREGSAVE_OFF + ireg * 8; |
303 | frame->saved_regs[FP0_REGNUM + ireg] = reg_position; | |
c906108c SS |
304 | } |
305 | frame->saved_regs[PC_REGNUM] = sigcontext_addr + SIGFRAME_PC_OFF; | |
306 | return; | |
307 | } | |
308 | ||
309 | proc_desc = frame->proc_desc; | |
310 | if (proc_desc == NULL) | |
311 | /* I'm not sure how/whether this can happen. Normally when we can't | |
312 | find a proc_desc, we "synthesize" one using heuristic_proc_desc | |
313 | and set the saved_regs right away. */ | |
314 | return; | |
315 | ||
316 | /* Fill in the offsets for the registers which gen_mask says | |
317 | were saved. */ | |
318 | ||
319 | reg_position = frame->frame + PROC_REG_OFFSET (proc_desc); | |
320 | mask = PROC_REG_MASK (proc_desc); | |
321 | ||
322 | returnreg = PROC_PC_REG (proc_desc); | |
323 | ||
324 | /* Note that RA is always saved first, regardless of its actual | |
325 | register number. */ | |
326 | if (mask & (1 << returnreg)) | |
327 | { | |
328 | frame->saved_regs[returnreg] = reg_position; | |
329 | reg_position += 8; | |
c5aa993b JM |
330 | mask &= ~(1 << returnreg); /* Clear bit for RA so we |
331 | don't save again later. */ | |
c906108c SS |
332 | } |
333 | ||
c5aa993b | 334 | for (ireg = 0; ireg <= 31; ++ireg) |
c906108c SS |
335 | if (mask & (1 << ireg)) |
336 | { | |
337 | frame->saved_regs[ireg] = reg_position; | |
338 | reg_position += 8; | |
339 | } | |
340 | ||
341 | /* Fill in the offsets for the registers which float_mask says | |
342 | were saved. */ | |
343 | ||
344 | reg_position = frame->frame + PROC_FREG_OFFSET (proc_desc); | |
345 | mask = PROC_FREG_MASK (proc_desc); | |
346 | ||
c5aa993b | 347 | for (ireg = 0; ireg <= 31; ++ireg) |
c906108c SS |
348 | if (mask & (1 << ireg)) |
349 | { | |
c5aa993b | 350 | frame->saved_regs[FP0_REGNUM + ireg] = reg_position; |
c906108c SS |
351 | reg_position += 8; |
352 | } | |
353 | ||
354 | frame->saved_regs[PC_REGNUM] = frame->saved_regs[returnreg]; | |
355 | } | |
356 | ||
357 | static CORE_ADDR | |
c5aa993b | 358 | read_next_frame_reg (fi, regno) |
c906108c SS |
359 | struct frame_info *fi; |
360 | int regno; | |
361 | { | |
362 | for (; fi; fi = fi->next) | |
363 | { | |
364 | /* We have to get the saved sp from the sigcontext | |
c5aa993b | 365 | if it is a signal handler frame. */ |
c906108c SS |
366 | if (regno == SP_REGNUM && !fi->signal_handler_caller) |
367 | return fi->frame; | |
368 | else | |
369 | { | |
370 | if (fi->saved_regs == NULL) | |
371 | alpha_find_saved_regs (fi); | |
372 | if (fi->saved_regs[regno]) | |
c5aa993b | 373 | return read_memory_integer (fi->saved_regs[regno], 8); |
c906108c SS |
374 | } |
375 | } | |
c5aa993b | 376 | return read_register (regno); |
c906108c SS |
377 | } |
378 | ||
379 | CORE_ADDR | |
c5aa993b | 380 | alpha_frame_saved_pc (frame) |
c906108c SS |
381 | struct frame_info *frame; |
382 | { | |
383 | alpha_extra_func_info_t proc_desc = frame->proc_desc; | |
384 | /* We have to get the saved pc from the sigcontext | |
385 | if it is a signal handler frame. */ | |
386 | int pcreg = frame->signal_handler_caller ? PC_REGNUM : frame->pc_reg; | |
387 | ||
c5aa993b JM |
388 | if (proc_desc && PROC_DESC_IS_DUMMY (proc_desc)) |
389 | return read_memory_integer (frame->frame - 8, 8); | |
c906108c | 390 | |
c5aa993b | 391 | return read_next_frame_reg (frame, pcreg); |
c906108c SS |
392 | } |
393 | ||
394 | CORE_ADDR | |
395 | alpha_saved_pc_after_call (frame) | |
396 | struct frame_info *frame; | |
397 | { | |
398 | CORE_ADDR pc = frame->pc; | |
399 | CORE_ADDR tmp; | |
400 | alpha_extra_func_info_t proc_desc; | |
401 | int pcreg; | |
402 | ||
403 | /* Skip over shared library trampoline if necessary. */ | |
404 | tmp = SKIP_TRAMPOLINE_CODE (pc); | |
405 | if (tmp != 0) | |
406 | pc = tmp; | |
407 | ||
408 | proc_desc = find_proc_desc (pc, frame->next); | |
409 | pcreg = proc_desc ? PROC_PC_REG (proc_desc) : RA_REGNUM; | |
410 | ||
411 | if (frame->signal_handler_caller) | |
412 | return alpha_frame_saved_pc (frame); | |
413 | else | |
414 | return read_register (pcreg); | |
415 | } | |
416 | ||
417 | ||
418 | static struct alpha_extra_func_info temp_proc_desc; | |
419 | static struct frame_saved_regs temp_saved_regs; | |
420 | ||
421 | /* Nonzero if instruction at PC is a return instruction. "ret | |
422 | $zero,($ra),1" on alpha. */ | |
423 | ||
424 | static int | |
425 | alpha_about_to_return (pc) | |
426 | CORE_ADDR pc; | |
427 | { | |
428 | return read_memory_integer (pc, 4) == 0x6bfa8001; | |
429 | } | |
430 | ||
431 | ||
432 | ||
433 | /* This fencepost looks highly suspicious to me. Removing it also | |
434 | seems suspicious as it could affect remote debugging across serial | |
435 | lines. */ | |
436 | ||
437 | static CORE_ADDR | |
c5aa993b JM |
438 | heuristic_proc_start (pc) |
439 | CORE_ADDR pc; | |
c906108c | 440 | { |
c5aa993b JM |
441 | CORE_ADDR start_pc = pc; |
442 | CORE_ADDR fence = start_pc - heuristic_fence_post; | |
c906108c | 443 | |
c5aa993b JM |
444 | if (start_pc == 0) |
445 | return 0; | |
c906108c | 446 | |
c5aa993b JM |
447 | if (heuristic_fence_post == UINT_MAX |
448 | || fence < VM_MIN_ADDRESS) | |
449 | fence = VM_MIN_ADDRESS; | |
c906108c | 450 | |
c5aa993b JM |
451 | /* search back for previous return */ |
452 | for (start_pc -= 4;; start_pc -= 4) | |
453 | if (start_pc < fence) | |
454 | { | |
455 | /* It's not clear to me why we reach this point when | |
456 | stop_soon_quietly, but with this test, at least we | |
457 | don't print out warnings for every child forked (eg, on | |
458 | decstation). 22apr93 rich@cygnus.com. */ | |
459 | if (!stop_soon_quietly) | |
c906108c | 460 | { |
c5aa993b JM |
461 | static int blurb_printed = 0; |
462 | ||
463 | if (fence == VM_MIN_ADDRESS) | |
464 | warning ("Hit beginning of text section without finding"); | |
465 | else | |
466 | warning ("Hit heuristic-fence-post without finding"); | |
467 | ||
468 | warning ("enclosing function for address 0x%lx", pc); | |
469 | if (!blurb_printed) | |
c906108c | 470 | { |
c5aa993b | 471 | printf_filtered ("\ |
c906108c SS |
472 | This warning occurs if you are debugging a function without any symbols\n\ |
473 | (for example, in a stripped executable). In that case, you may wish to\n\ | |
474 | increase the size of the search with the `set heuristic-fence-post' command.\n\ | |
475 | \n\ | |
476 | Otherwise, you told GDB there was a function where there isn't one, or\n\ | |
477 | (more likely) you have encountered a bug in GDB.\n"); | |
c5aa993b | 478 | blurb_printed = 1; |
c906108c | 479 | } |
c906108c | 480 | } |
c906108c | 481 | |
c5aa993b JM |
482 | return 0; |
483 | } | |
484 | else if (alpha_about_to_return (start_pc)) | |
485 | break; | |
486 | ||
487 | start_pc += 4; /* skip return */ | |
488 | return start_pc; | |
c906108c SS |
489 | } |
490 | ||
491 | static alpha_extra_func_info_t | |
c5aa993b JM |
492 | heuristic_proc_desc (start_pc, limit_pc, next_frame) |
493 | CORE_ADDR start_pc, limit_pc; | |
494 | struct frame_info *next_frame; | |
c906108c | 495 | { |
c5aa993b JM |
496 | CORE_ADDR sp = read_next_frame_reg (next_frame, SP_REGNUM); |
497 | CORE_ADDR cur_pc; | |
498 | int frame_size; | |
499 | int has_frame_reg = 0; | |
500 | unsigned long reg_mask = 0; | |
501 | int pcreg = -1; | |
502 | ||
503 | if (start_pc == 0) | |
504 | return NULL; | |
505 | memset (&temp_proc_desc, '\0', sizeof (temp_proc_desc)); | |
506 | memset (&temp_saved_regs, '\0', sizeof (struct frame_saved_regs)); | |
507 | PROC_LOW_ADDR (&temp_proc_desc) = start_pc; | |
508 | ||
509 | if (start_pc + 200 < limit_pc) | |
510 | limit_pc = start_pc + 200; | |
511 | frame_size = 0; | |
512 | for (cur_pc = start_pc; cur_pc < limit_pc; cur_pc += 4) | |
513 | { | |
514 | char buf[4]; | |
515 | unsigned long word; | |
516 | int status; | |
c906108c | 517 | |
c5aa993b JM |
518 | status = read_memory_nobpt (cur_pc, buf, 4); |
519 | if (status) | |
520 | memory_error (status, cur_pc); | |
521 | word = extract_unsigned_integer (buf, 4); | |
c906108c | 522 | |
c5aa993b JM |
523 | if ((word & 0xffff0000) == 0x23de0000) /* lda $sp,n($sp) */ |
524 | { | |
525 | if (word & 0x8000) | |
526 | frame_size += (-word) & 0xffff; | |
527 | else | |
528 | /* Exit loop if a positive stack adjustment is found, which | |
529 | usually means that the stack cleanup code in the function | |
530 | epilogue is reached. */ | |
531 | break; | |
532 | } | |
533 | else if ((word & 0xfc1f0000) == 0xb41e0000 /* stq reg,n($sp) */ | |
534 | && (word & 0xffff0000) != 0xb7fe0000) /* reg != $zero */ | |
535 | { | |
536 | int reg = (word & 0x03e00000) >> 21; | |
537 | reg_mask |= 1 << reg; | |
538 | temp_saved_regs.regs[reg] = sp + (short) word; | |
539 | ||
540 | /* Starting with OSF/1-3.2C, the system libraries are shipped | |
541 | without local symbols, but they still contain procedure | |
542 | descriptors without a symbol reference. GDB is currently | |
543 | unable to find these procedure descriptors and uses | |
544 | heuristic_proc_desc instead. | |
545 | As some low level compiler support routines (__div*, __add*) | |
546 | use a non-standard return address register, we have to | |
547 | add some heuristics to determine the return address register, | |
548 | or stepping over these routines will fail. | |
549 | Usually the return address register is the first register | |
550 | saved on the stack, but assembler optimization might | |
551 | rearrange the register saves. | |
552 | So we recognize only a few registers (t7, t9, ra) within | |
553 | the procedure prologue as valid return address registers. | |
554 | If we encounter a return instruction, we extract the | |
555 | the return address register from it. | |
556 | ||
557 | FIXME: Rewriting GDB to access the procedure descriptors, | |
558 | e.g. via the minimal symbol table, might obviate this hack. */ | |
559 | if (pcreg == -1 | |
560 | && cur_pc < (start_pc + 80) | |
561 | && (reg == T7_REGNUM || reg == T9_REGNUM || reg == RA_REGNUM)) | |
562 | pcreg = reg; | |
563 | } | |
564 | else if ((word & 0xffe0ffff) == 0x6be08001) /* ret zero,reg,1 */ | |
565 | pcreg = (word >> 16) & 0x1f; | |
566 | else if (word == 0x47de040f) /* bis sp,sp fp */ | |
567 | has_frame_reg = 1; | |
568 | } | |
569 | if (pcreg == -1) | |
570 | { | |
571 | /* If we haven't found a valid return address register yet, | |
572 | keep searching in the procedure prologue. */ | |
573 | while (cur_pc < (limit_pc + 80) && cur_pc < (start_pc + 80)) | |
574 | { | |
575 | char buf[4]; | |
576 | unsigned long word; | |
c906108c | 577 | |
c5aa993b JM |
578 | if (read_memory_nobpt (cur_pc, buf, 4)) |
579 | break; | |
580 | cur_pc += 4; | |
581 | word = extract_unsigned_integer (buf, 4); | |
c906108c | 582 | |
c5aa993b JM |
583 | if ((word & 0xfc1f0000) == 0xb41e0000 /* stq reg,n($sp) */ |
584 | && (word & 0xffff0000) != 0xb7fe0000) /* reg != $zero */ | |
585 | { | |
586 | int reg = (word & 0x03e00000) >> 21; | |
587 | if (reg == T7_REGNUM || reg == T9_REGNUM || reg == RA_REGNUM) | |
588 | { | |
589 | pcreg = reg; | |
590 | break; | |
591 | } | |
592 | } | |
593 | else if ((word & 0xffe0ffff) == 0x6be08001) /* ret zero,reg,1 */ | |
594 | { | |
595 | pcreg = (word >> 16) & 0x1f; | |
596 | break; | |
597 | } | |
598 | } | |
599 | } | |
c906108c | 600 | |
c5aa993b JM |
601 | if (has_frame_reg) |
602 | PROC_FRAME_REG (&temp_proc_desc) = GCC_FP_REGNUM; | |
603 | else | |
604 | PROC_FRAME_REG (&temp_proc_desc) = SP_REGNUM; | |
605 | PROC_FRAME_OFFSET (&temp_proc_desc) = frame_size; | |
606 | PROC_REG_MASK (&temp_proc_desc) = reg_mask; | |
607 | PROC_PC_REG (&temp_proc_desc) = (pcreg == -1) ? RA_REGNUM : pcreg; | |
608 | PROC_LOCALOFF (&temp_proc_desc) = 0; /* XXX - bogus */ | |
609 | return &temp_proc_desc; | |
c906108c SS |
610 | } |
611 | ||
612 | /* This returns the PC of the first inst after the prologue. If we can't | |
613 | find the prologue, then return 0. */ | |
614 | ||
615 | static CORE_ADDR | |
616 | after_prologue (pc, proc_desc) | |
617 | CORE_ADDR pc; | |
618 | alpha_extra_func_info_t proc_desc; | |
619 | { | |
620 | struct symtab_and_line sal; | |
621 | CORE_ADDR func_addr, func_end; | |
622 | ||
623 | if (!proc_desc) | |
624 | proc_desc = find_proc_desc (pc, NULL); | |
625 | ||
626 | if (proc_desc) | |
627 | { | |
628 | if (PROC_DESC_IS_DYN_SIGTRAMP (proc_desc)) | |
629 | return PROC_LOW_ADDR (proc_desc); /* "prologue" is in kernel */ | |
630 | ||
631 | /* If function is frameless, then we need to do it the hard way. I | |
c5aa993b | 632 | strongly suspect that frameless always means prologueless... */ |
c906108c SS |
633 | if (PROC_FRAME_REG (proc_desc) == SP_REGNUM |
634 | && PROC_FRAME_OFFSET (proc_desc) == 0) | |
635 | return 0; | |
636 | } | |
637 | ||
638 | if (!find_pc_partial_function (pc, NULL, &func_addr, &func_end)) | |
639 | return 0; /* Unknown */ | |
640 | ||
641 | sal = find_pc_line (func_addr, 0); | |
642 | ||
643 | if (sal.end < func_end) | |
644 | return sal.end; | |
645 | ||
646 | /* The line after the prologue is after the end of the function. In this | |
647 | case, tell the caller to find the prologue the hard way. */ | |
648 | ||
649 | return 0; | |
650 | } | |
651 | ||
652 | /* Return non-zero if we *might* be in a function prologue. Return zero if we | |
653 | are definitively *not* in a function prologue. */ | |
654 | ||
655 | static int | |
656 | alpha_in_prologue (pc, proc_desc) | |
657 | CORE_ADDR pc; | |
658 | alpha_extra_func_info_t proc_desc; | |
659 | { | |
660 | CORE_ADDR after_prologue_pc; | |
661 | ||
662 | after_prologue_pc = after_prologue (pc, proc_desc); | |
663 | ||
664 | if (after_prologue_pc == 0 | |
665 | || pc < after_prologue_pc) | |
666 | return 1; | |
667 | else | |
668 | return 0; | |
669 | } | |
670 | ||
671 | static alpha_extra_func_info_t | |
672 | find_proc_desc (pc, next_frame) | |
c5aa993b JM |
673 | CORE_ADDR pc; |
674 | struct frame_info *next_frame; | |
c906108c SS |
675 | { |
676 | alpha_extra_func_info_t proc_desc; | |
677 | struct block *b; | |
678 | struct symbol *sym; | |
679 | CORE_ADDR startaddr; | |
680 | ||
681 | /* Try to get the proc_desc from the linked call dummy proc_descs | |
682 | if the pc is in the call dummy. | |
683 | This is hairy. In the case of nested dummy calls we have to find the | |
684 | right proc_desc, but we might not yet know the frame for the dummy | |
685 | as it will be contained in the proc_desc we are searching for. | |
686 | So we have to find the proc_desc whose frame is closest to the current | |
687 | stack pointer. */ | |
688 | ||
689 | if (PC_IN_CALL_DUMMY (pc, 0, 0)) | |
690 | { | |
691 | struct linked_proc_info *link; | |
692 | CORE_ADDR sp = read_next_frame_reg (next_frame, SP_REGNUM); | |
693 | alpha_extra_func_info_t found_proc_desc = NULL; | |
694 | long min_distance = LONG_MAX; | |
695 | ||
696 | for (link = linked_proc_desc_table; link; link = link->next) | |
697 | { | |
698 | long distance = (CORE_ADDR) PROC_DUMMY_FRAME (&link->info) - sp; | |
699 | if (distance > 0 && distance < min_distance) | |
700 | { | |
701 | min_distance = distance; | |
702 | found_proc_desc = &link->info; | |
703 | } | |
704 | } | |
705 | if (found_proc_desc != NULL) | |
706 | return found_proc_desc; | |
707 | } | |
708 | ||
c5aa993b | 709 | b = block_for_pc (pc); |
c906108c SS |
710 | |
711 | find_pc_partial_function (pc, NULL, &startaddr, NULL); | |
712 | if (b == NULL) | |
713 | sym = NULL; | |
714 | else | |
715 | { | |
716 | if (startaddr > BLOCK_START (b)) | |
717 | /* This is the "pathological" case referred to in a comment in | |
718 | print_frame_info. It might be better to move this check into | |
719 | symbol reading. */ | |
720 | sym = NULL; | |
721 | else | |
722 | sym = lookup_symbol (MIPS_EFI_SYMBOL_NAME, b, LABEL_NAMESPACE, | |
723 | 0, NULL); | |
724 | } | |
725 | ||
726 | /* If we never found a PDR for this function in symbol reading, then | |
727 | examine prologues to find the information. */ | |
728 | if (sym && ((mips_extra_func_info_t) SYMBOL_VALUE (sym))->pdr.framereg == -1) | |
729 | sym = NULL; | |
730 | ||
731 | if (sym) | |
732 | { | |
c5aa993b JM |
733 | /* IF this is the topmost frame AND |
734 | * (this proc does not have debugging information OR | |
735 | * the PC is in the procedure prologue) | |
736 | * THEN create a "heuristic" proc_desc (by analyzing | |
737 | * the actual code) to replace the "official" proc_desc. | |
738 | */ | |
739 | proc_desc = (alpha_extra_func_info_t) SYMBOL_VALUE (sym); | |
740 | if (next_frame == NULL) | |
741 | { | |
742 | if (PROC_DESC_IS_DUMMY (proc_desc) || alpha_in_prologue (pc, proc_desc)) | |
743 | { | |
744 | alpha_extra_func_info_t found_heuristic = | |
745 | heuristic_proc_desc (PROC_LOW_ADDR (proc_desc), | |
746 | pc, next_frame); | |
747 | if (found_heuristic) | |
748 | { | |
749 | PROC_LOCALOFF (found_heuristic) = | |
750 | PROC_LOCALOFF (proc_desc); | |
751 | PROC_PC_REG (found_heuristic) = PROC_PC_REG (proc_desc); | |
752 | proc_desc = found_heuristic; | |
753 | } | |
754 | } | |
755 | } | |
c906108c SS |
756 | } |
757 | else | |
758 | { | |
759 | long offset; | |
760 | ||
761 | /* Is linked_proc_desc_table really necessary? It only seems to be used | |
c5aa993b JM |
762 | by procedure call dummys. However, the procedures being called ought |
763 | to have their own proc_descs, and even if they don't, | |
764 | heuristic_proc_desc knows how to create them! */ | |
c906108c SS |
765 | |
766 | register struct linked_proc_info *link; | |
767 | for (link = linked_proc_desc_table; link; link = link->next) | |
c5aa993b JM |
768 | if (PROC_LOW_ADDR (&link->info) <= pc |
769 | && PROC_HIGH_ADDR (&link->info) > pc) | |
770 | return &link->info; | |
c906108c SS |
771 | |
772 | /* If PC is inside a dynamically generated sigtramp handler, | |
c5aa993b | 773 | create and push a procedure descriptor for that code: */ |
c906108c SS |
774 | offset = DYNAMIC_SIGTRAMP_OFFSET (pc); |
775 | if (offset >= 0) | |
776 | return push_sigtramp_desc (pc - offset); | |
777 | ||
778 | /* If heuristic_fence_post is non-zero, determine the procedure | |
c5aa993b JM |
779 | start address by examining the instructions. |
780 | This allows us to find the start address of static functions which | |
781 | have no symbolic information, as startaddr would have been set to | |
782 | the preceding global function start address by the | |
783 | find_pc_partial_function call above. */ | |
c906108c SS |
784 | if (startaddr == 0 || heuristic_fence_post != 0) |
785 | startaddr = heuristic_proc_start (pc); | |
786 | ||
787 | proc_desc = | |
788 | heuristic_proc_desc (startaddr, pc, next_frame); | |
789 | } | |
790 | return proc_desc; | |
791 | } | |
792 | ||
793 | alpha_extra_func_info_t cached_proc_desc; | |
794 | ||
795 | CORE_ADDR | |
c5aa993b JM |
796 | alpha_frame_chain (frame) |
797 | struct frame_info *frame; | |
c906108c | 798 | { |
c5aa993b JM |
799 | alpha_extra_func_info_t proc_desc; |
800 | CORE_ADDR saved_pc = FRAME_SAVED_PC (frame); | |
801 | ||
802 | if (saved_pc == 0 || inside_entry_file (saved_pc)) | |
803 | return 0; | |
804 | ||
805 | proc_desc = find_proc_desc (saved_pc, frame); | |
806 | if (!proc_desc) | |
807 | return 0; | |
808 | ||
809 | cached_proc_desc = proc_desc; | |
810 | ||
811 | /* Fetch the frame pointer for a dummy frame from the procedure | |
812 | descriptor. */ | |
813 | if (PROC_DESC_IS_DUMMY (proc_desc)) | |
814 | return (CORE_ADDR) PROC_DUMMY_FRAME (proc_desc); | |
815 | ||
816 | /* If no frame pointer and frame size is zero, we must be at end | |
817 | of stack (or otherwise hosed). If we don't check frame size, | |
818 | we loop forever if we see a zero size frame. */ | |
819 | if (PROC_FRAME_REG (proc_desc) == SP_REGNUM | |
820 | && PROC_FRAME_OFFSET (proc_desc) == 0 | |
821 | /* The previous frame from a sigtramp frame might be frameless | |
822 | and have frame size zero. */ | |
823 | && !frame->signal_handler_caller) | |
824 | return FRAME_PAST_SIGTRAMP_FRAME (frame, saved_pc); | |
825 | else | |
826 | return read_next_frame_reg (frame, PROC_FRAME_REG (proc_desc)) | |
827 | + PROC_FRAME_OFFSET (proc_desc); | |
c906108c SS |
828 | } |
829 | ||
830 | void | |
831 | init_extra_frame_info (frame) | |
832 | struct frame_info *frame; | |
833 | { | |
834 | /* Use proc_desc calculated in frame_chain */ | |
835 | alpha_extra_func_info_t proc_desc = | |
c5aa993b | 836 | frame->next ? cached_proc_desc : find_proc_desc (frame->pc, frame->next); |
c906108c SS |
837 | |
838 | frame->saved_regs = NULL; | |
839 | frame->localoff = 0; | |
840 | frame->pc_reg = RA_REGNUM; | |
841 | frame->proc_desc = proc_desc == &temp_proc_desc ? 0 : proc_desc; | |
842 | if (proc_desc) | |
843 | { | |
844 | /* Get the locals offset and the saved pc register from the | |
c5aa993b JM |
845 | procedure descriptor, they are valid even if we are in the |
846 | middle of the prologue. */ | |
847 | frame->localoff = PROC_LOCALOFF (proc_desc); | |
848 | frame->pc_reg = PROC_PC_REG (proc_desc); | |
c906108c SS |
849 | |
850 | /* Fixup frame-pointer - only needed for top frame */ | |
851 | ||
852 | /* Fetch the frame pointer for a dummy frame from the procedure | |
c5aa993b JM |
853 | descriptor. */ |
854 | if (PROC_DESC_IS_DUMMY (proc_desc)) | |
855 | frame->frame = (CORE_ADDR) PROC_DUMMY_FRAME (proc_desc); | |
c906108c SS |
856 | |
857 | /* This may not be quite right, if proc has a real frame register. | |
c5aa993b JM |
858 | Get the value of the frame relative sp, procedure might have been |
859 | interrupted by a signal at it's very start. */ | |
c906108c SS |
860 | else if (frame->pc == PROC_LOW_ADDR (proc_desc) |
861 | && !PROC_DESC_IS_DYN_SIGTRAMP (proc_desc)) | |
862 | frame->frame = read_next_frame_reg (frame->next, SP_REGNUM); | |
863 | else | |
864 | frame->frame = read_next_frame_reg (frame->next, PROC_FRAME_REG (proc_desc)) | |
865 | + PROC_FRAME_OFFSET (proc_desc); | |
866 | ||
867 | if (proc_desc == &temp_proc_desc) | |
868 | { | |
869 | char *name; | |
870 | ||
871 | /* Do not set the saved registers for a sigtramp frame, | |
872 | alpha_find_saved_registers will do that for us. | |
873 | We can't use frame->signal_handler_caller, it is not yet set. */ | |
874 | find_pc_partial_function (frame->pc, &name, | |
c5aa993b | 875 | (CORE_ADDR *) NULL, (CORE_ADDR *) NULL); |
c906108c SS |
876 | if (!IN_SIGTRAMP (frame->pc, name)) |
877 | { | |
c5aa993b | 878 | frame->saved_regs = (CORE_ADDR *) |
c906108c SS |
879 | frame_obstack_alloc (SIZEOF_FRAME_SAVED_REGS); |
880 | memcpy (frame->saved_regs, temp_saved_regs.regs, SIZEOF_FRAME_SAVED_REGS); | |
881 | frame->saved_regs[PC_REGNUM] | |
882 | = frame->saved_regs[RA_REGNUM]; | |
883 | } | |
884 | } | |
885 | } | |
886 | } | |
887 | ||
888 | /* ALPHA stack frames are almost impenetrable. When execution stops, | |
889 | we basically have to look at symbol information for the function | |
890 | that we stopped in, which tells us *which* register (if any) is | |
891 | the base of the frame pointer, and what offset from that register | |
892 | the frame itself is at. | |
893 | ||
894 | This presents a problem when trying to examine a stack in memory | |
895 | (that isn't executing at the moment), using the "frame" command. We | |
896 | don't have a PC, nor do we have any registers except SP. | |
897 | ||
898 | This routine takes two arguments, SP and PC, and tries to make the | |
899 | cached frames look as if these two arguments defined a frame on the | |
900 | cache. This allows the rest of info frame to extract the important | |
901 | arguments without difficulty. */ | |
902 | ||
903 | struct frame_info * | |
904 | setup_arbitrary_frame (argc, argv) | |
905 | int argc; | |
906 | CORE_ADDR *argv; | |
907 | { | |
908 | if (argc != 2) | |
909 | error ("ALPHA frame specifications require two arguments: sp and pc"); | |
910 | ||
911 | return create_new_frame (argv[0], argv[1]); | |
912 | } | |
913 | ||
914 | /* The alpha passes the first six arguments in the registers, the rest on | |
915 | the stack. The register arguments are eventually transferred to the | |
916 | argument transfer area immediately below the stack by the called function | |
917 | anyway. So we `push' at least six arguments on the stack, `reload' the | |
918 | argument registers and then adjust the stack pointer to point past the | |
919 | sixth argument. This algorithm simplifies the passing of a large struct | |
920 | which extends from the registers to the stack. | |
921 | If the called function is returning a structure, the address of the | |
922 | structure to be returned is passed as a hidden first argument. */ | |
923 | ||
924 | CORE_ADDR | |
925 | alpha_push_arguments (nargs, args, sp, struct_return, struct_addr) | |
926 | int nargs; | |
927 | value_ptr *args; | |
928 | CORE_ADDR sp; | |
929 | int struct_return; | |
930 | CORE_ADDR struct_addr; | |
931 | { | |
7a292a7a | 932 | int i; |
c906108c SS |
933 | int accumulate_size = struct_return ? 8 : 0; |
934 | int arg_regs_size = ALPHA_NUM_ARG_REGS * 8; | |
c5aa993b JM |
935 | struct alpha_arg |
936 | { | |
937 | char *contents; | |
938 | int len; | |
939 | int offset; | |
940 | }; | |
c906108c | 941 | struct alpha_arg *alpha_args = |
c5aa993b | 942 | (struct alpha_arg *) alloca (nargs * sizeof (struct alpha_arg)); |
c906108c SS |
943 | register struct alpha_arg *m_arg; |
944 | char raw_buffer[sizeof (CORE_ADDR)]; | |
945 | int required_arg_regs; | |
946 | ||
947 | for (i = 0, m_arg = alpha_args; i < nargs; i++, m_arg++) | |
948 | { | |
949 | value_ptr arg = args[i]; | |
950 | struct type *arg_type = check_typedef (VALUE_TYPE (arg)); | |
951 | /* Cast argument to long if necessary as the compiler does it too. */ | |
952 | switch (TYPE_CODE (arg_type)) | |
953 | { | |
954 | case TYPE_CODE_INT: | |
955 | case TYPE_CODE_BOOL: | |
956 | case TYPE_CODE_CHAR: | |
957 | case TYPE_CODE_RANGE: | |
958 | case TYPE_CODE_ENUM: | |
959 | if (TYPE_LENGTH (arg_type) < TYPE_LENGTH (builtin_type_long)) | |
960 | { | |
961 | arg_type = builtin_type_long; | |
962 | arg = value_cast (arg_type, arg); | |
963 | } | |
964 | break; | |
965 | default: | |
966 | break; | |
967 | } | |
968 | m_arg->len = TYPE_LENGTH (arg_type); | |
969 | m_arg->offset = accumulate_size; | |
970 | accumulate_size = (accumulate_size + m_arg->len + 7) & ~7; | |
c5aa993b | 971 | m_arg->contents = VALUE_CONTENTS (arg); |
c906108c SS |
972 | } |
973 | ||
974 | /* Determine required argument register loads, loading an argument register | |
975 | is expensive as it uses three ptrace calls. */ | |
976 | required_arg_regs = accumulate_size / 8; | |
977 | if (required_arg_regs > ALPHA_NUM_ARG_REGS) | |
978 | required_arg_regs = ALPHA_NUM_ARG_REGS; | |
979 | ||
980 | /* Make room for the arguments on the stack. */ | |
981 | if (accumulate_size < arg_regs_size) | |
c5aa993b | 982 | accumulate_size = arg_regs_size; |
c906108c SS |
983 | sp -= accumulate_size; |
984 | ||
985 | /* Keep sp aligned to a multiple of 16 as the compiler does it too. */ | |
986 | sp &= ~15; | |
987 | ||
988 | /* `Push' arguments on the stack. */ | |
c5aa993b JM |
989 | for (i = nargs; m_arg--, --i >= 0;) |
990 | write_memory (sp + m_arg->offset, m_arg->contents, m_arg->len); | |
c906108c SS |
991 | if (struct_return) |
992 | { | |
993 | store_address (raw_buffer, sizeof (CORE_ADDR), struct_addr); | |
994 | write_memory (sp, raw_buffer, sizeof (CORE_ADDR)); | |
995 | } | |
996 | ||
997 | /* Load the argument registers. */ | |
998 | for (i = 0; i < required_arg_regs; i++) | |
999 | { | |
1000 | LONGEST val; | |
1001 | ||
1002 | val = read_memory_integer (sp + i * 8, 8); | |
1003 | write_register (A0_REGNUM + i, val); | |
1004 | write_register (FPA0_REGNUM + i, val); | |
1005 | } | |
1006 | ||
1007 | return sp + arg_regs_size; | |
1008 | } | |
1009 | ||
1010 | void | |
c5aa993b | 1011 | alpha_push_dummy_frame () |
c906108c SS |
1012 | { |
1013 | int ireg; | |
1014 | struct linked_proc_info *link; | |
1015 | alpha_extra_func_info_t proc_desc; | |
1016 | CORE_ADDR sp = read_register (SP_REGNUM); | |
1017 | CORE_ADDR save_address; | |
1018 | char raw_buffer[MAX_REGISTER_RAW_SIZE]; | |
1019 | unsigned long mask; | |
1020 | ||
c5aa993b | 1021 | link = (struct linked_proc_info *) xmalloc (sizeof (struct linked_proc_info)); |
c906108c SS |
1022 | link->next = linked_proc_desc_table; |
1023 | linked_proc_desc_table = link; | |
c5aa993b | 1024 | |
c906108c SS |
1025 | proc_desc = &link->info; |
1026 | ||
1027 | /* | |
1028 | * The registers we must save are all those not preserved across | |
1029 | * procedure calls. | |
1030 | * In addition, we must save the PC and RA. | |
1031 | * | |
1032 | * Dummy frame layout: | |
1033 | * (high memory) | |
c5aa993b | 1034 | * Saved PC |
c906108c SS |
1035 | * Saved F30 |
1036 | * ... | |
1037 | * Saved F0 | |
c5aa993b JM |
1038 | * Saved R29 |
1039 | * ... | |
1040 | * Saved R0 | |
1041 | * Saved R26 (RA) | |
1042 | * Parameter build area | |
c906108c SS |
1043 | * (low memory) |
1044 | */ | |
1045 | ||
1046 | /* MASK(i,j) == (1<<i) + (1<<(i+1)) + ... + (1<<j)). Assume i<=j<31. */ | |
1047 | #define MASK(i,j) ((((LONGEST)1 << ((j)+1)) - 1) ^ (((LONGEST)1 << (i)) - 1)) | |
1048 | #define GEN_REG_SAVE_MASK (MASK(0,8) | MASK(16,29)) | |
1049 | #define GEN_REG_SAVE_COUNT 24 | |
1050 | #define FLOAT_REG_SAVE_MASK (MASK(0,1) | MASK(10,30)) | |
1051 | #define FLOAT_REG_SAVE_COUNT 23 | |
1052 | /* The special register is the PC as we have no bit for it in the save masks. | |
1053 | alpha_frame_saved_pc knows where the pc is saved in a dummy frame. */ | |
1054 | #define SPECIAL_REG_SAVE_COUNT 1 | |
1055 | ||
c5aa993b JM |
1056 | PROC_REG_MASK (proc_desc) = GEN_REG_SAVE_MASK; |
1057 | PROC_FREG_MASK (proc_desc) = FLOAT_REG_SAVE_MASK; | |
c906108c SS |
1058 | /* PROC_REG_OFFSET is the offset from the dummy frame to the saved RA, |
1059 | but keep SP aligned to a multiple of 16. */ | |
c5aa993b JM |
1060 | PROC_REG_OFFSET (proc_desc) = |
1061 | -((8 * (SPECIAL_REG_SAVE_COUNT | |
c906108c SS |
1062 | + GEN_REG_SAVE_COUNT |
1063 | + FLOAT_REG_SAVE_COUNT) | |
c5aa993b JM |
1064 | + 15) & ~15); |
1065 | PROC_FREG_OFFSET (proc_desc) = | |
1066 | PROC_REG_OFFSET (proc_desc) + 8 * GEN_REG_SAVE_COUNT; | |
c906108c SS |
1067 | |
1068 | /* Save general registers. | |
1069 | The return address register is the first saved register, all other | |
1070 | registers follow in ascending order. | |
1071 | The PC is saved immediately below the SP. */ | |
c5aa993b | 1072 | save_address = sp + PROC_REG_OFFSET (proc_desc); |
c906108c SS |
1073 | store_address (raw_buffer, 8, read_register (RA_REGNUM)); |
1074 | write_memory (save_address, raw_buffer, 8); | |
1075 | save_address += 8; | |
c5aa993b | 1076 | mask = PROC_REG_MASK (proc_desc) & 0xffffffffL; |
c906108c SS |
1077 | for (ireg = 0; mask; ireg++, mask >>= 1) |
1078 | if (mask & 1) | |
1079 | { | |
1080 | if (ireg == RA_REGNUM) | |
1081 | continue; | |
1082 | store_address (raw_buffer, 8, read_register (ireg)); | |
1083 | write_memory (save_address, raw_buffer, 8); | |
1084 | save_address += 8; | |
1085 | } | |
1086 | ||
1087 | store_address (raw_buffer, 8, read_register (PC_REGNUM)); | |
1088 | write_memory (sp - 8, raw_buffer, 8); | |
1089 | ||
1090 | /* Save floating point registers. */ | |
c5aa993b JM |
1091 | save_address = sp + PROC_FREG_OFFSET (proc_desc); |
1092 | mask = PROC_FREG_MASK (proc_desc) & 0xffffffffL; | |
c906108c SS |
1093 | for (ireg = 0; mask; ireg++, mask >>= 1) |
1094 | if (mask & 1) | |
1095 | { | |
1096 | store_address (raw_buffer, 8, read_register (ireg + FP0_REGNUM)); | |
1097 | write_memory (save_address, raw_buffer, 8); | |
1098 | save_address += 8; | |
1099 | } | |
1100 | ||
1101 | /* Set and save the frame address for the dummy. | |
1102 | This is tricky. The only registers that are suitable for a frame save | |
1103 | are those that are preserved across procedure calls (s0-s6). But if | |
1104 | a read system call is interrupted and then a dummy call is made | |
1105 | (see testsuite/gdb.t17/interrupt.exp) the dummy call hangs till the read | |
1106 | is satisfied. Then it returns with the s0-s6 registers set to the values | |
1107 | on entry to the read system call and our dummy frame pointer would be | |
1108 | destroyed. So we save the dummy frame in the proc_desc and handle the | |
1109 | retrieval of the frame pointer of a dummy specifically. The frame register | |
1110 | is set to the virtual frame (pseudo) register, it's value will always | |
1111 | be read as zero and will help us to catch any errors in the dummy frame | |
1112 | retrieval code. */ | |
c5aa993b JM |
1113 | PROC_DUMMY_FRAME (proc_desc) = sp; |
1114 | PROC_FRAME_REG (proc_desc) = FP_REGNUM; | |
1115 | PROC_FRAME_OFFSET (proc_desc) = 0; | |
1116 | sp += PROC_REG_OFFSET (proc_desc); | |
c906108c SS |
1117 | write_register (SP_REGNUM, sp); |
1118 | ||
c5aa993b JM |
1119 | PROC_LOW_ADDR (proc_desc) = CALL_DUMMY_ADDRESS (); |
1120 | PROC_HIGH_ADDR (proc_desc) = PROC_LOW_ADDR (proc_desc) + 4; | |
c906108c | 1121 | |
c5aa993b JM |
1122 | SET_PROC_DESC_IS_DUMMY (proc_desc); |
1123 | PROC_PC_REG (proc_desc) = RA_REGNUM; | |
c906108c SS |
1124 | } |
1125 | ||
1126 | void | |
c5aa993b | 1127 | alpha_pop_frame () |
c906108c SS |
1128 | { |
1129 | register int regnum; | |
1130 | struct frame_info *frame = get_current_frame (); | |
1131 | CORE_ADDR new_sp = frame->frame; | |
1132 | ||
1133 | alpha_extra_func_info_t proc_desc = frame->proc_desc; | |
1134 | ||
9e0b60a8 JM |
1135 | /* we need proc_desc to know how to restore the registers; |
1136 | if it is NULL, construct (a temporary) one */ | |
1137 | if (proc_desc == NULL) | |
c5aa993b | 1138 | proc_desc = find_proc_desc (frame->pc, frame->next); |
9e0b60a8 JM |
1139 | |
1140 | /* Question: should we copy this proc_desc and save it in | |
1141 | frame->proc_desc? If we do, who will free it? | |
1142 | For now, we don't save a copy... */ | |
1143 | ||
c5aa993b | 1144 | write_register (PC_REGNUM, FRAME_SAVED_PC (frame)); |
c906108c SS |
1145 | if (frame->saved_regs == NULL) |
1146 | alpha_find_saved_regs (frame); | |
1147 | if (proc_desc) | |
1148 | { | |
c5aa993b JM |
1149 | for (regnum = 32; --regnum >= 0;) |
1150 | if (PROC_REG_MASK (proc_desc) & (1 << regnum)) | |
c906108c SS |
1151 | write_register (regnum, |
1152 | read_memory_integer (frame->saved_regs[regnum], | |
1153 | 8)); | |
c5aa993b JM |
1154 | for (regnum = 32; --regnum >= 0;) |
1155 | if (PROC_FREG_MASK (proc_desc) & (1 << regnum)) | |
c906108c | 1156 | write_register (regnum + FP0_REGNUM, |
c5aa993b | 1157 | read_memory_integer (frame->saved_regs[regnum + FP0_REGNUM], 8)); |
c906108c SS |
1158 | } |
1159 | write_register (SP_REGNUM, new_sp); | |
1160 | flush_cached_frames (); | |
1161 | ||
c5aa993b | 1162 | if (proc_desc && (PROC_DESC_IS_DUMMY (proc_desc) |
c906108c SS |
1163 | || PROC_DESC_IS_DYN_SIGTRAMP (proc_desc))) |
1164 | { | |
1165 | struct linked_proc_info *pi_ptr, *prev_ptr; | |
1166 | ||
1167 | for (pi_ptr = linked_proc_desc_table, prev_ptr = NULL; | |
1168 | pi_ptr != NULL; | |
1169 | prev_ptr = pi_ptr, pi_ptr = pi_ptr->next) | |
1170 | { | |
1171 | if (&pi_ptr->info == proc_desc) | |
1172 | break; | |
1173 | } | |
1174 | ||
1175 | if (pi_ptr == NULL) | |
1176 | error ("Can't locate dummy extra frame info\n"); | |
1177 | ||
1178 | if (prev_ptr != NULL) | |
1179 | prev_ptr->next = pi_ptr->next; | |
1180 | else | |
1181 | linked_proc_desc_table = pi_ptr->next; | |
1182 | ||
1183 | free (pi_ptr); | |
1184 | } | |
1185 | } | |
1186 | \f | |
1187 | /* To skip prologues, I use this predicate. Returns either PC itself | |
1188 | if the code at PC does not look like a function prologue; otherwise | |
1189 | returns an address that (if we're lucky) follows the prologue. If | |
1190 | LENIENT, then we must skip everything which is involved in setting | |
1191 | up the frame (it's OK to skip more, just so long as we don't skip | |
1192 | anything which might clobber the registers which are being saved. | |
1193 | Currently we must not skip more on the alpha, but we might the lenient | |
1194 | stuff some day. */ | |
1195 | ||
1196 | CORE_ADDR | |
1197 | alpha_skip_prologue (pc, lenient) | |
1198 | CORE_ADDR pc; | |
1199 | int lenient; | |
1200 | { | |
c5aa993b JM |
1201 | unsigned long inst; |
1202 | int offset; | |
1203 | CORE_ADDR post_prologue_pc; | |
1204 | char buf[4]; | |
c906108c SS |
1205 | |
1206 | #ifdef GDB_TARGET_HAS_SHARED_LIBS | |
c5aa993b JM |
1207 | /* Silently return the unaltered pc upon memory errors. |
1208 | This could happen on OSF/1 if decode_line_1 tries to skip the | |
1209 | prologue for quickstarted shared library functions when the | |
1210 | shared library is not yet mapped in. | |
1211 | Reading target memory is slow over serial lines, so we perform | |
1212 | this check only if the target has shared libraries. */ | |
1213 | if (target_read_memory (pc, buf, 4)) | |
1214 | return pc; | |
c906108c SS |
1215 | #endif |
1216 | ||
c5aa993b JM |
1217 | /* See if we can determine the end of the prologue via the symbol table. |
1218 | If so, then return either PC, or the PC after the prologue, whichever | |
1219 | is greater. */ | |
c906108c | 1220 | |
c5aa993b | 1221 | post_prologue_pc = after_prologue (pc, NULL); |
c906108c | 1222 | |
c5aa993b JM |
1223 | if (post_prologue_pc != 0) |
1224 | return max (pc, post_prologue_pc); | |
c906108c | 1225 | |
c5aa993b JM |
1226 | /* Can't determine prologue from the symbol table, need to examine |
1227 | instructions. */ | |
c906108c | 1228 | |
c5aa993b JM |
1229 | /* Skip the typical prologue instructions. These are the stack adjustment |
1230 | instruction and the instructions that save registers on the stack | |
1231 | or in the gcc frame. */ | |
1232 | for (offset = 0; offset < 100; offset += 4) | |
1233 | { | |
1234 | int status; | |
1235 | ||
1236 | status = read_memory_nobpt (pc + offset, buf, 4); | |
1237 | if (status) | |
1238 | memory_error (status, pc + offset); | |
1239 | inst = extract_unsigned_integer (buf, 4); | |
1240 | ||
1241 | /* The alpha has no delay slots. But let's keep the lenient stuff, | |
1242 | we might need it for something else in the future. */ | |
1243 | if (lenient && 0) | |
1244 | continue; | |
1245 | ||
1246 | if ((inst & 0xffff0000) == 0x27bb0000) /* ldah $gp,n($t12) */ | |
1247 | continue; | |
1248 | if ((inst & 0xffff0000) == 0x23bd0000) /* lda $gp,n($gp) */ | |
1249 | continue; | |
1250 | if ((inst & 0xffff0000) == 0x23de0000) /* lda $sp,n($sp) */ | |
1251 | continue; | |
1252 | if ((inst & 0xffe01fff) == 0x43c0153e) /* subq $sp,n,$sp */ | |
1253 | continue; | |
1254 | ||
1255 | if ((inst & 0xfc1f0000) == 0xb41e0000 | |
1256 | && (inst & 0xffff0000) != 0xb7fe0000) | |
1257 | continue; /* stq reg,n($sp) */ | |
1258 | /* reg != $zero */ | |
1259 | if ((inst & 0xfc1f0000) == 0x9c1e0000 | |
1260 | && (inst & 0xffff0000) != 0x9ffe0000) | |
1261 | continue; /* stt reg,n($sp) */ | |
1262 | /* reg != $zero */ | |
1263 | if (inst == 0x47de040f) /* bis sp,sp,fp */ | |
1264 | continue; | |
1265 | ||
1266 | break; | |
c906108c | 1267 | } |
c5aa993b | 1268 | return pc + offset; |
c906108c SS |
1269 | } |
1270 | ||
1271 | #if 0 | |
1272 | /* Is address PC in the prologue (loosely defined) for function at | |
1273 | STARTADDR? */ | |
1274 | ||
1275 | static int | |
1276 | alpha_in_lenient_prologue (startaddr, pc) | |
1277 | CORE_ADDR startaddr; | |
1278 | CORE_ADDR pc; | |
1279 | { | |
1280 | CORE_ADDR end_prologue = alpha_skip_prologue (startaddr, 1); | |
1281 | return pc >= startaddr && pc < end_prologue; | |
1282 | } | |
1283 | #endif | |
1284 | ||
1285 | /* The alpha needs a conversion between register and memory format if | |
1286 | the register is a floating point register and | |
c5aa993b | 1287 | memory format is float, as the register format must be double |
c906108c | 1288 | or |
c5aa993b JM |
1289 | memory format is an integer with 4 bytes or less, as the representation |
1290 | of integers in floating point registers is different. */ | |
c906108c SS |
1291 | void |
1292 | alpha_register_convert_to_virtual (regnum, valtype, raw_buffer, virtual_buffer) | |
c5aa993b JM |
1293 | int regnum; |
1294 | struct type *valtype; | |
1295 | char *raw_buffer; | |
1296 | char *virtual_buffer; | |
c906108c SS |
1297 | { |
1298 | if (TYPE_LENGTH (valtype) >= REGISTER_RAW_SIZE (regnum)) | |
1299 | { | |
1300 | memcpy (virtual_buffer, raw_buffer, REGISTER_VIRTUAL_SIZE (regnum)); | |
1301 | return; | |
1302 | } | |
1303 | ||
1304 | if (TYPE_CODE (valtype) == TYPE_CODE_FLT) | |
1305 | { | |
1306 | double d = extract_floating (raw_buffer, REGISTER_RAW_SIZE (regnum)); | |
1307 | store_floating (virtual_buffer, TYPE_LENGTH (valtype), d); | |
1308 | } | |
1309 | else if (TYPE_CODE (valtype) == TYPE_CODE_INT && TYPE_LENGTH (valtype) <= 4) | |
1310 | { | |
1311 | ULONGEST l; | |
1312 | l = extract_unsigned_integer (raw_buffer, REGISTER_RAW_SIZE (regnum)); | |
1313 | l = ((l >> 32) & 0xc0000000) | ((l >> 29) & 0x3fffffff); | |
1314 | store_unsigned_integer (virtual_buffer, TYPE_LENGTH (valtype), l); | |
1315 | } | |
1316 | else | |
1317 | error ("Cannot retrieve value from floating point register"); | |
1318 | } | |
1319 | ||
1320 | void | |
1321 | alpha_register_convert_to_raw (valtype, regnum, virtual_buffer, raw_buffer) | |
c5aa993b JM |
1322 | struct type *valtype; |
1323 | int regnum; | |
1324 | char *virtual_buffer; | |
1325 | char *raw_buffer; | |
c906108c SS |
1326 | { |
1327 | if (TYPE_LENGTH (valtype) >= REGISTER_RAW_SIZE (regnum)) | |
1328 | { | |
1329 | memcpy (raw_buffer, virtual_buffer, REGISTER_RAW_SIZE (regnum)); | |
1330 | return; | |
1331 | } | |
1332 | ||
1333 | if (TYPE_CODE (valtype) == TYPE_CODE_FLT) | |
1334 | { | |
1335 | double d = extract_floating (virtual_buffer, TYPE_LENGTH (valtype)); | |
1336 | store_floating (raw_buffer, REGISTER_RAW_SIZE (regnum), d); | |
1337 | } | |
1338 | else if (TYPE_CODE (valtype) == TYPE_CODE_INT && TYPE_LENGTH (valtype) <= 4) | |
1339 | { | |
1340 | ULONGEST l; | |
1341 | if (TYPE_UNSIGNED (valtype)) | |
1342 | l = extract_unsigned_integer (virtual_buffer, TYPE_LENGTH (valtype)); | |
1343 | else | |
1344 | l = extract_signed_integer (virtual_buffer, TYPE_LENGTH (valtype)); | |
1345 | l = ((l & 0xc0000000) << 32) | ((l & 0x3fffffff) << 29); | |
1346 | store_unsigned_integer (raw_buffer, REGISTER_RAW_SIZE (regnum), l); | |
1347 | } | |
1348 | else | |
1349 | error ("Cannot store value in floating point register"); | |
1350 | } | |
1351 | ||
1352 | /* Given a return value in `regbuf' with a type `valtype', | |
1353 | extract and copy its value into `valbuf'. */ | |
1354 | ||
1355 | void | |
1356 | alpha_extract_return_value (valtype, regbuf, valbuf) | |
c5aa993b JM |
1357 | struct type *valtype; |
1358 | char regbuf[REGISTER_BYTES]; | |
1359 | char *valbuf; | |
c906108c SS |
1360 | { |
1361 | if (TYPE_CODE (valtype) == TYPE_CODE_FLT) | |
1362 | alpha_register_convert_to_virtual (FP0_REGNUM, valtype, | |
1363 | regbuf + REGISTER_BYTE (FP0_REGNUM), | |
1364 | valbuf); | |
1365 | else | |
1366 | memcpy (valbuf, regbuf + REGISTER_BYTE (V0_REGNUM), TYPE_LENGTH (valtype)); | |
1367 | } | |
1368 | ||
1369 | /* Given a return value in `regbuf' with a type `valtype', | |
1370 | write its value into the appropriate register. */ | |
1371 | ||
1372 | void | |
1373 | alpha_store_return_value (valtype, valbuf) | |
c5aa993b JM |
1374 | struct type *valtype; |
1375 | char *valbuf; | |
c906108c SS |
1376 | { |
1377 | char raw_buffer[MAX_REGISTER_RAW_SIZE]; | |
1378 | int regnum = V0_REGNUM; | |
1379 | int length = TYPE_LENGTH (valtype); | |
c5aa993b | 1380 | |
c906108c SS |
1381 | if (TYPE_CODE (valtype) == TYPE_CODE_FLT) |
1382 | { | |
1383 | regnum = FP0_REGNUM; | |
1384 | length = REGISTER_RAW_SIZE (regnum); | |
1385 | alpha_register_convert_to_raw (valtype, regnum, valbuf, raw_buffer); | |
1386 | } | |
1387 | else | |
1388 | memcpy (raw_buffer, valbuf, length); | |
1389 | ||
1390 | write_register_bytes (REGISTER_BYTE (regnum), raw_buffer, length); | |
1391 | } | |
1392 | ||
1393 | /* Just like reinit_frame_cache, but with the right arguments to be | |
1394 | callable as an sfunc. */ | |
1395 | ||
1396 | static void | |
1397 | reinit_frame_cache_sfunc (args, from_tty, c) | |
1398 | char *args; | |
1399 | int from_tty; | |
1400 | struct cmd_list_element *c; | |
1401 | { | |
1402 | reinit_frame_cache (); | |
1403 | } | |
1404 | ||
1405 | /* This is the definition of CALL_DUMMY_ADDRESS. It's a heuristic that is used | |
1406 | to find a convenient place in the text segment to stick a breakpoint to | |
1407 | detect the completion of a target function call (ala call_function_by_hand). | |
1408 | */ | |
1409 | ||
1410 | CORE_ADDR | |
1411 | alpha_call_dummy_address () | |
1412 | { | |
1413 | CORE_ADDR entry; | |
1414 | struct minimal_symbol *sym; | |
1415 | ||
1416 | entry = entry_point_address (); | |
1417 | ||
1418 | if (entry != 0) | |
1419 | return entry; | |
1420 | ||
1421 | sym = lookup_minimal_symbol ("_Prelude", NULL, symfile_objfile); | |
1422 | ||
1423 | if (!sym || MSYMBOL_TYPE (sym) != mst_text) | |
1424 | return 0; | |
1425 | else | |
1426 | return SYMBOL_VALUE_ADDRESS (sym) + 4; | |
1427 | } | |
1428 | ||
1429 | void | |
1430 | _initialize_alpha_tdep () | |
1431 | { | |
1432 | struct cmd_list_element *c; | |
1433 | ||
1434 | tm_print_insn = print_insn_alpha; | |
1435 | ||
1436 | /* Let the user set the fence post for heuristic_proc_start. */ | |
1437 | ||
1438 | /* We really would like to have both "0" and "unlimited" work, but | |
1439 | command.c doesn't deal with that. So make it a var_zinteger | |
1440 | because the user can always use "999999" or some such for unlimited. */ | |
1441 | c = add_set_cmd ("heuristic-fence-post", class_support, var_zinteger, | |
1442 | (char *) &heuristic_fence_post, | |
1443 | "\ | |
1444 | Set the distance searched for the start of a function.\n\ | |
1445 | If you are debugging a stripped executable, GDB needs to search through the\n\ | |
1446 | program for the start of a function. This command sets the distance of the\n\ | |
1447 | search. The only need to set it is when debugging a stripped executable.", | |
1448 | &setlist); | |
1449 | /* We need to throw away the frame cache when we set this, since it | |
1450 | might change our ability to get backtraces. */ | |
1451 | c->function.sfunc = reinit_frame_cache_sfunc; | |
1452 | add_show_from_set (c, &showlist); | |
1453 | } |