Commit | Line | Data |
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c906108c SS |
1 | /* Intel 386 target-dependent stuff. |
2 | Copyright (C) 1988, 1989, 1991, 1994, 1995, 1996, 1998 | |
3 | Free Software Foundation, Inc. | |
4 | ||
c5aa993b | 5 | This file is part of GDB. |
c906108c | 6 | |
c5aa993b JM |
7 | This program is free software; you can redistribute it and/or modify |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2 of the License, or | |
10 | (at your option) any later version. | |
c906108c | 11 | |
c5aa993b JM |
12 | This program is distributed in the hope that it will be useful, |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
c906108c | 16 | |
c5aa993b JM |
17 | You should have received a copy of the GNU General Public License |
18 | along with this program; if not, write to the Free Software | |
19 | Foundation, Inc., 59 Temple Place - Suite 330, | |
20 | Boston, MA 02111-1307, USA. */ | |
c906108c SS |
21 | |
22 | #include "defs.h" | |
23 | #include "gdb_string.h" | |
24 | #include "frame.h" | |
25 | #include "inferior.h" | |
26 | #include "gdbcore.h" | |
27 | #include "target.h" | |
28 | #include "floatformat.h" | |
29 | #include "symtab.h" | |
30 | #include "gdbcmd.h" | |
31 | #include "command.h" | |
32 | ||
33 | static long i386_get_frame_setup PARAMS ((CORE_ADDR)); | |
34 | ||
35 | static void i386_follow_jump PARAMS ((void)); | |
36 | ||
37 | static void codestream_read PARAMS ((unsigned char *, int)); | |
38 | ||
39 | static void codestream_seek PARAMS ((CORE_ADDR)); | |
40 | ||
41 | static unsigned char codestream_fill PARAMS ((int)); | |
42 | ||
43 | CORE_ADDR skip_trampoline_code PARAMS ((CORE_ADDR, char *)); | |
44 | ||
45 | static int gdb_print_insn_i386 (bfd_vma, disassemble_info *); | |
46 | ||
47 | void _initialize_i386_tdep PARAMS ((void)); | |
48 | ||
49 | /* This is the variable the is set with "set disassembly-flavor", | |
c5aa993b | 50 | and its legitimate values. */ |
c906108c SS |
51 | static char att_flavor[] = "att"; |
52 | static char intel_flavor[] = "intel"; | |
c5aa993b JM |
53 | static char *valid_flavors[] = |
54 | { | |
c906108c SS |
55 | att_flavor, |
56 | intel_flavor, | |
57 | NULL | |
58 | }; | |
59 | static char *disassembly_flavor = att_flavor; | |
60 | ||
d4f3574e SS |
61 | static void i386_print_register PARAMS ((char *, int, int)); |
62 | ||
7a292a7a SS |
63 | /* This is used to keep the bfd arch_info in sync with the disassembly flavor. */ |
64 | static void set_disassembly_flavor_sfunc PARAMS ((char *, int, struct cmd_list_element *)); | |
d4f3574e | 65 | static void set_disassembly_flavor PARAMS ((void)); |
7a292a7a | 66 | |
c906108c SS |
67 | /* Stdio style buffering was used to minimize calls to ptrace, but this |
68 | buffering did not take into account that the code section being accessed | |
69 | may not be an even number of buffers long (even if the buffer is only | |
70 | sizeof(int) long). In cases where the code section size happened to | |
71 | be a non-integral number of buffers long, attempting to read the last | |
72 | buffer would fail. Simply using target_read_memory and ignoring errors, | |
73 | rather than read_memory, is not the correct solution, since legitimate | |
74 | access errors would then be totally ignored. To properly handle this | |
75 | situation and continue to use buffering would require that this code | |
76 | be able to determine the minimum code section size granularity (not the | |
77 | alignment of the section itself, since the actual failing case that | |
78 | pointed out this problem had a section alignment of 4 but was not a | |
79 | multiple of 4 bytes long), on a target by target basis, and then | |
80 | adjust it's buffer size accordingly. This is messy, but potentially | |
81 | feasible. It probably needs the bfd library's help and support. For | |
82 | now, the buffer size is set to 1. (FIXME -fnf) */ | |
83 | ||
84 | #define CODESTREAM_BUFSIZ 1 /* Was sizeof(int), see note above. */ | |
85 | static CORE_ADDR codestream_next_addr; | |
86 | static CORE_ADDR codestream_addr; | |
87 | static unsigned char codestream_buf[CODESTREAM_BUFSIZ]; | |
88 | static int codestream_off; | |
89 | static int codestream_cnt; | |
90 | ||
91 | #define codestream_tell() (codestream_addr + codestream_off) | |
92 | #define codestream_peek() (codestream_cnt == 0 ? \ | |
93 | codestream_fill(1): codestream_buf[codestream_off]) | |
94 | #define codestream_get() (codestream_cnt-- == 0 ? \ | |
95 | codestream_fill(0) : codestream_buf[codestream_off++]) | |
96 | ||
c5aa993b | 97 | static unsigned char |
c906108c | 98 | codestream_fill (peek_flag) |
c5aa993b | 99 | int peek_flag; |
c906108c SS |
100 | { |
101 | codestream_addr = codestream_next_addr; | |
102 | codestream_next_addr += CODESTREAM_BUFSIZ; | |
103 | codestream_off = 0; | |
104 | codestream_cnt = CODESTREAM_BUFSIZ; | |
105 | read_memory (codestream_addr, (char *) codestream_buf, CODESTREAM_BUFSIZ); | |
c5aa993b | 106 | |
c906108c | 107 | if (peek_flag) |
c5aa993b | 108 | return (codestream_peek ()); |
c906108c | 109 | else |
c5aa993b | 110 | return (codestream_get ()); |
c906108c SS |
111 | } |
112 | ||
113 | static void | |
114 | codestream_seek (place) | |
c5aa993b | 115 | CORE_ADDR place; |
c906108c SS |
116 | { |
117 | codestream_next_addr = place / CODESTREAM_BUFSIZ; | |
118 | codestream_next_addr *= CODESTREAM_BUFSIZ; | |
119 | codestream_cnt = 0; | |
120 | codestream_fill (1); | |
c5aa993b | 121 | while (codestream_tell () != place) |
c906108c SS |
122 | codestream_get (); |
123 | } | |
124 | ||
125 | static void | |
126 | codestream_read (buf, count) | |
127 | unsigned char *buf; | |
128 | int count; | |
129 | { | |
130 | unsigned char *p; | |
131 | int i; | |
132 | p = buf; | |
133 | for (i = 0; i < count; i++) | |
134 | *p++ = codestream_get (); | |
135 | } | |
136 | ||
137 | /* next instruction is a jump, move to target */ | |
138 | ||
139 | static void | |
140 | i386_follow_jump () | |
141 | { | |
142 | unsigned char buf[4]; | |
143 | long delta; | |
144 | ||
145 | int data16; | |
146 | CORE_ADDR pos; | |
147 | ||
148 | pos = codestream_tell (); | |
149 | ||
150 | data16 = 0; | |
151 | if (codestream_peek () == 0x66) | |
152 | { | |
153 | codestream_get (); | |
154 | data16 = 1; | |
155 | } | |
156 | ||
157 | switch (codestream_get ()) | |
158 | { | |
159 | case 0xe9: | |
160 | /* relative jump: if data16 == 0, disp32, else disp16 */ | |
161 | if (data16) | |
162 | { | |
163 | codestream_read (buf, 2); | |
164 | delta = extract_signed_integer (buf, 2); | |
165 | ||
166 | /* include size of jmp inst (including the 0x66 prefix). */ | |
c5aa993b | 167 | pos += delta + 4; |
c906108c SS |
168 | } |
169 | else | |
170 | { | |
171 | codestream_read (buf, 4); | |
172 | delta = extract_signed_integer (buf, 4); | |
173 | ||
174 | pos += delta + 5; | |
175 | } | |
176 | break; | |
177 | case 0xeb: | |
178 | /* relative jump, disp8 (ignore data16) */ | |
179 | codestream_read (buf, 1); | |
180 | /* Sign-extend it. */ | |
181 | delta = extract_signed_integer (buf, 1); | |
182 | ||
183 | pos += delta + 2; | |
184 | break; | |
185 | } | |
186 | codestream_seek (pos); | |
187 | } | |
188 | ||
189 | /* | |
190 | * find & return amound a local space allocated, and advance codestream to | |
191 | * first register push (if any) | |
192 | * | |
193 | * if entry sequence doesn't make sense, return -1, and leave | |
194 | * codestream pointer random | |
195 | */ | |
196 | ||
197 | static long | |
198 | i386_get_frame_setup (pc) | |
199 | CORE_ADDR pc; | |
200 | { | |
201 | unsigned char op; | |
202 | ||
203 | codestream_seek (pc); | |
204 | ||
205 | i386_follow_jump (); | |
206 | ||
207 | op = codestream_get (); | |
208 | ||
209 | if (op == 0x58) /* popl %eax */ | |
210 | { | |
211 | /* | |
212 | * this function must start with | |
213 | * | |
c5aa993b | 214 | * popl %eax 0x58 |
c906108c SS |
215 | * xchgl %eax, (%esp) 0x87 0x04 0x24 |
216 | * or xchgl %eax, 0(%esp) 0x87 0x44 0x24 0x00 | |
217 | * | |
218 | * (the system 5 compiler puts out the second xchg | |
219 | * inst, and the assembler doesn't try to optimize it, | |
220 | * so the 'sib' form gets generated) | |
221 | * | |
222 | * this sequence is used to get the address of the return | |
223 | * buffer for a function that returns a structure | |
224 | */ | |
225 | int pos; | |
226 | unsigned char buf[4]; | |
c5aa993b JM |
227 | static unsigned char proto1[3] = |
228 | {0x87, 0x04, 0x24}; | |
229 | static unsigned char proto2[4] = | |
230 | {0x87, 0x44, 0x24, 0x00}; | |
c906108c SS |
231 | pos = codestream_tell (); |
232 | codestream_read (buf, 4); | |
233 | if (memcmp (buf, proto1, 3) == 0) | |
234 | pos += 3; | |
235 | else if (memcmp (buf, proto2, 4) == 0) | |
236 | pos += 4; | |
237 | ||
238 | codestream_seek (pos); | |
c5aa993b | 239 | op = codestream_get (); /* update next opcode */ |
c906108c SS |
240 | } |
241 | ||
242 | if (op == 0x68 || op == 0x6a) | |
243 | { | |
244 | /* | |
245 | * this function may start with | |
246 | * | |
247 | * pushl constant | |
248 | * call _probe | |
249 | * addl $4, %esp | |
250 | * followed by | |
251 | * pushl %ebp | |
252 | * etc. | |
253 | */ | |
254 | int pos; | |
255 | unsigned char buf[8]; | |
256 | ||
257 | /* Skip past the pushl instruction; it has either a one-byte | |
258 | or a four-byte operand, depending on the opcode. */ | |
259 | pos = codestream_tell (); | |
260 | if (op == 0x68) | |
261 | pos += 4; | |
262 | else | |
263 | pos += 1; | |
264 | codestream_seek (pos); | |
265 | ||
266 | /* Read the following 8 bytes, which should be "call _probe" (6 bytes) | |
267 | followed by "addl $4,%esp" (2 bytes). */ | |
268 | codestream_read (buf, sizeof (buf)); | |
269 | if (buf[0] == 0xe8 && buf[6] == 0xc4 && buf[7] == 0x4) | |
270 | pos += sizeof (buf); | |
271 | codestream_seek (pos); | |
c5aa993b | 272 | op = codestream_get (); /* update next opcode */ |
c906108c SS |
273 | } |
274 | ||
275 | if (op == 0x55) /* pushl %ebp */ | |
c5aa993b | 276 | { |
c906108c SS |
277 | /* check for movl %esp, %ebp - can be written two ways */ |
278 | switch (codestream_get ()) | |
279 | { | |
280 | case 0x8b: | |
281 | if (codestream_get () != 0xec) | |
282 | return (-1); | |
283 | break; | |
284 | case 0x89: | |
285 | if (codestream_get () != 0xe5) | |
286 | return (-1); | |
287 | break; | |
288 | default: | |
289 | return (-1); | |
290 | } | |
291 | /* check for stack adjustment | |
c5aa993b | 292 | |
c906108c SS |
293 | * subl $XXX, %esp |
294 | * | |
295 | * note: you can't subtract a 16 bit immediate | |
296 | * from a 32 bit reg, so we don't have to worry | |
297 | * about a data16 prefix | |
298 | */ | |
299 | op = codestream_peek (); | |
300 | if (op == 0x83) | |
301 | { | |
302 | /* subl with 8 bit immed */ | |
303 | codestream_get (); | |
304 | if (codestream_get () != 0xec) | |
305 | /* Some instruction starting with 0x83 other than subl. */ | |
306 | { | |
307 | codestream_seek (codestream_tell () - 2); | |
308 | return 0; | |
309 | } | |
310 | /* subl with signed byte immediate | |
311 | * (though it wouldn't make sense to be negative) | |
312 | */ | |
c5aa993b | 313 | return (codestream_get ()); |
c906108c SS |
314 | } |
315 | else if (op == 0x81) | |
316 | { | |
317 | char buf[4]; | |
318 | /* Maybe it is subl with 32 bit immedediate. */ | |
c5aa993b | 319 | codestream_get (); |
c906108c SS |
320 | if (codestream_get () != 0xec) |
321 | /* Some instruction starting with 0x81 other than subl. */ | |
322 | { | |
323 | codestream_seek (codestream_tell () - 2); | |
324 | return 0; | |
325 | } | |
326 | /* It is subl with 32 bit immediate. */ | |
c5aa993b | 327 | codestream_read ((unsigned char *) buf, 4); |
c906108c SS |
328 | return extract_signed_integer (buf, 4); |
329 | } | |
330 | else | |
331 | { | |
332 | return (0); | |
333 | } | |
334 | } | |
335 | else if (op == 0xc8) | |
336 | { | |
337 | char buf[2]; | |
338 | /* enter instruction: arg is 16 bit unsigned immed */ | |
c5aa993b JM |
339 | codestream_read ((unsigned char *) buf, 2); |
340 | codestream_get (); /* flush final byte of enter instruction */ | |
c906108c SS |
341 | return extract_unsigned_integer (buf, 2); |
342 | } | |
343 | return (-1); | |
344 | } | |
345 | ||
346 | /* Return number of args passed to a frame. | |
347 | Can return -1, meaning no way to tell. */ | |
348 | ||
349 | int | |
350 | i386_frame_num_args (fi) | |
351 | struct frame_info *fi; | |
352 | { | |
353 | #if 1 | |
354 | return -1; | |
355 | #else | |
356 | /* This loses because not only might the compiler not be popping the | |
357 | args right after the function call, it might be popping args from both | |
358 | this call and a previous one, and we would say there are more args | |
359 | than there really are. */ | |
360 | ||
c5aa993b JM |
361 | int retpc; |
362 | unsigned char op; | |
c906108c SS |
363 | struct frame_info *pfi; |
364 | ||
365 | /* on the 386, the instruction following the call could be: | |
366 | popl %ecx - one arg | |
367 | addl $imm, %esp - imm/4 args; imm may be 8 or 32 bits | |
368 | anything else - zero args */ | |
369 | ||
370 | int frameless; | |
371 | ||
392a587b | 372 | frameless = FRAMELESS_FUNCTION_INVOCATION (fi); |
c906108c SS |
373 | if (frameless) |
374 | /* In the absence of a frame pointer, GDB doesn't get correct values | |
375 | for nameless arguments. Return -1, so it doesn't print any | |
376 | nameless arguments. */ | |
377 | return -1; | |
378 | ||
c5aa993b | 379 | pfi = get_prev_frame (fi); |
c906108c SS |
380 | if (pfi == 0) |
381 | { | |
382 | /* Note: this can happen if we are looking at the frame for | |
c5aa993b JM |
383 | main, because FRAME_CHAIN_VALID won't let us go into |
384 | start. If we have debugging symbols, that's not really | |
385 | a big deal; it just means it will only show as many arguments | |
386 | to main as are declared. */ | |
c906108c SS |
387 | return -1; |
388 | } | |
389 | else | |
390 | { | |
c5aa993b JM |
391 | retpc = pfi->pc; |
392 | op = read_memory_integer (retpc, 1); | |
393 | if (op == 0x59) | |
394 | /* pop %ecx */ | |
395 | return 1; | |
c906108c SS |
396 | else if (op == 0x83) |
397 | { | |
c5aa993b JM |
398 | op = read_memory_integer (retpc + 1, 1); |
399 | if (op == 0xc4) | |
400 | /* addl $<signed imm 8 bits>, %esp */ | |
401 | return (read_memory_integer (retpc + 2, 1) & 0xff) / 4; | |
c906108c SS |
402 | else |
403 | return 0; | |
404 | } | |
405 | else if (op == 0x81) | |
c5aa993b JM |
406 | { /* add with 32 bit immediate */ |
407 | op = read_memory_integer (retpc + 1, 1); | |
408 | if (op == 0xc4) | |
409 | /* addl $<imm 32>, %esp */ | |
410 | return read_memory_integer (retpc + 2, 4) / 4; | |
c906108c SS |
411 | else |
412 | return 0; | |
413 | } | |
414 | else | |
415 | { | |
416 | return 0; | |
417 | } | |
418 | } | |
419 | #endif | |
420 | } | |
421 | ||
422 | /* | |
423 | * parse the first few instructions of the function to see | |
424 | * what registers were stored. | |
425 | * | |
426 | * We handle these cases: | |
427 | * | |
428 | * The startup sequence can be at the start of the function, | |
429 | * or the function can start with a branch to startup code at the end. | |
430 | * | |
431 | * %ebp can be set up with either the 'enter' instruction, or | |
432 | * 'pushl %ebp, movl %esp, %ebp' (enter is too slow to be useful, | |
433 | * but was once used in the sys5 compiler) | |
434 | * | |
435 | * Local space is allocated just below the saved %ebp by either the | |
436 | * 'enter' instruction, or by 'subl $<size>, %esp'. 'enter' has | |
437 | * a 16 bit unsigned argument for space to allocate, and the | |
438 | * 'addl' instruction could have either a signed byte, or | |
439 | * 32 bit immediate. | |
440 | * | |
441 | * Next, the registers used by this function are pushed. In | |
442 | * the sys5 compiler they will always be in the order: %edi, %esi, %ebx | |
443 | * (and sometimes a harmless bug causes it to also save but not restore %eax); | |
444 | * however, the code below is willing to see the pushes in any order, | |
445 | * and will handle up to 8 of them. | |
446 | * | |
447 | * If the setup sequence is at the end of the function, then the | |
448 | * next instruction will be a branch back to the start. | |
449 | */ | |
450 | ||
451 | void | |
452 | i386_frame_find_saved_regs (fip, fsrp) | |
453 | struct frame_info *fip; | |
454 | struct frame_saved_regs *fsrp; | |
455 | { | |
456 | long locals = -1; | |
457 | unsigned char op; | |
458 | CORE_ADDR dummy_bottom; | |
459 | CORE_ADDR adr; | |
460 | CORE_ADDR pc; | |
461 | int i; | |
c5aa993b | 462 | |
c906108c | 463 | memset (fsrp, 0, sizeof *fsrp); |
c5aa993b | 464 | |
c906108c SS |
465 | /* if frame is the end of a dummy, compute where the |
466 | * beginning would be | |
467 | */ | |
468 | dummy_bottom = fip->frame - 4 - REGISTER_BYTES - CALL_DUMMY_LENGTH; | |
c5aa993b | 469 | |
c906108c | 470 | /* check if the PC is in the stack, in a dummy frame */ |
c5aa993b | 471 | if (dummy_bottom <= fip->pc && fip->pc <= fip->frame) |
c906108c SS |
472 | { |
473 | /* all regs were saved by push_call_dummy () */ | |
474 | adr = fip->frame; | |
c5aa993b | 475 | for (i = 0; i < NUM_REGS; i++) |
c906108c SS |
476 | { |
477 | adr -= REGISTER_RAW_SIZE (i); | |
478 | fsrp->regs[i] = adr; | |
479 | } | |
480 | return; | |
481 | } | |
c5aa993b | 482 | |
c906108c SS |
483 | pc = get_pc_function_start (fip->pc); |
484 | if (pc != 0) | |
485 | locals = i386_get_frame_setup (pc); | |
c5aa993b JM |
486 | |
487 | if (locals >= 0) | |
c906108c SS |
488 | { |
489 | adr = fip->frame - 4 - locals; | |
c5aa993b | 490 | for (i = 0; i < 8; i++) |
c906108c SS |
491 | { |
492 | op = codestream_get (); | |
493 | if (op < 0x50 || op > 0x57) | |
494 | break; | |
495 | #ifdef I386_REGNO_TO_SYMMETRY | |
496 | /* Dynix uses different internal numbering. Ick. */ | |
c5aa993b | 497 | fsrp->regs[I386_REGNO_TO_SYMMETRY (op - 0x50)] = adr; |
c906108c SS |
498 | #else |
499 | fsrp->regs[op - 0x50] = adr; | |
500 | #endif | |
501 | adr -= 4; | |
502 | } | |
503 | } | |
c5aa993b | 504 | |
c906108c SS |
505 | fsrp->regs[PC_REGNUM] = fip->frame + 4; |
506 | fsrp->regs[FP_REGNUM] = fip->frame; | |
507 | } | |
508 | ||
509 | /* return pc of first real instruction */ | |
510 | ||
511 | int | |
512 | i386_skip_prologue (pc) | |
513 | int pc; | |
514 | { | |
515 | unsigned char op; | |
516 | int i; | |
c5aa993b JM |
517 | static unsigned char pic_pat[6] = |
518 | {0xe8, 0, 0, 0, 0, /* call 0x0 */ | |
519 | 0x5b, /* popl %ebx */ | |
520 | }; | |
c906108c | 521 | CORE_ADDR pos; |
c5aa993b | 522 | |
c906108c SS |
523 | if (i386_get_frame_setup (pc) < 0) |
524 | return (pc); | |
c5aa993b | 525 | |
c906108c SS |
526 | /* found valid frame setup - codestream now points to |
527 | * start of push instructions for saving registers | |
528 | */ | |
c5aa993b | 529 | |
c906108c SS |
530 | /* skip over register saves */ |
531 | for (i = 0; i < 8; i++) | |
532 | { | |
533 | op = codestream_peek (); | |
534 | /* break if not pushl inst */ | |
c5aa993b | 535 | if (op < 0x50 || op > 0x57) |
c906108c SS |
536 | break; |
537 | codestream_get (); | |
538 | } | |
539 | ||
540 | /* The native cc on SVR4 in -K PIC mode inserts the following code to get | |
541 | the address of the global offset table (GOT) into register %ebx. | |
c5aa993b JM |
542 | call 0x0 |
543 | popl %ebx | |
544 | movl %ebx,x(%ebp) (optional) | |
545 | addl y,%ebx | |
c906108c SS |
546 | This code is with the rest of the prologue (at the end of the |
547 | function), so we have to skip it to get to the first real | |
548 | instruction at the start of the function. */ | |
c5aa993b | 549 | |
c906108c SS |
550 | pos = codestream_tell (); |
551 | for (i = 0; i < 6; i++) | |
552 | { | |
553 | op = codestream_get (); | |
c5aa993b | 554 | if (pic_pat[i] != op) |
c906108c SS |
555 | break; |
556 | } | |
557 | if (i == 6) | |
558 | { | |
559 | unsigned char buf[4]; | |
560 | long delta = 6; | |
561 | ||
562 | op = codestream_get (); | |
c5aa993b | 563 | if (op == 0x89) /* movl %ebx, x(%ebp) */ |
c906108c SS |
564 | { |
565 | op = codestream_get (); | |
c5aa993b | 566 | if (op == 0x5d) /* one byte offset from %ebp */ |
c906108c SS |
567 | { |
568 | delta += 3; | |
569 | codestream_read (buf, 1); | |
570 | } | |
c5aa993b | 571 | else if (op == 0x9d) /* four byte offset from %ebp */ |
c906108c SS |
572 | { |
573 | delta += 6; | |
574 | codestream_read (buf, 4); | |
575 | } | |
c5aa993b JM |
576 | else /* unexpected instruction */ |
577 | delta = -1; | |
578 | op = codestream_get (); | |
c906108c | 579 | } |
c5aa993b JM |
580 | /* addl y,%ebx */ |
581 | if (delta > 0 && op == 0x81 && codestream_get () == 0xc3) | |
c906108c | 582 | { |
c5aa993b | 583 | pos += delta + 6; |
c906108c SS |
584 | } |
585 | } | |
586 | codestream_seek (pos); | |
c5aa993b | 587 | |
c906108c | 588 | i386_follow_jump (); |
c5aa993b | 589 | |
c906108c SS |
590 | return (codestream_tell ()); |
591 | } | |
592 | ||
593 | void | |
594 | i386_push_dummy_frame () | |
595 | { | |
596 | CORE_ADDR sp = read_register (SP_REGNUM); | |
597 | int regnum; | |
598 | char regbuf[MAX_REGISTER_RAW_SIZE]; | |
c5aa993b | 599 | |
c906108c SS |
600 | sp = push_word (sp, read_register (PC_REGNUM)); |
601 | sp = push_word (sp, read_register (FP_REGNUM)); | |
602 | write_register (FP_REGNUM, sp); | |
603 | for (regnum = 0; regnum < NUM_REGS; regnum++) | |
604 | { | |
605 | read_register_gen (regnum, regbuf); | |
606 | sp = push_bytes (sp, regbuf, REGISTER_RAW_SIZE (regnum)); | |
607 | } | |
608 | write_register (SP_REGNUM, sp); | |
609 | } | |
610 | ||
611 | void | |
612 | i386_pop_frame () | |
613 | { | |
614 | struct frame_info *frame = get_current_frame (); | |
615 | CORE_ADDR fp; | |
616 | int regnum; | |
617 | struct frame_saved_regs fsr; | |
618 | char regbuf[MAX_REGISTER_RAW_SIZE]; | |
c5aa993b | 619 | |
c906108c SS |
620 | fp = FRAME_FP (frame); |
621 | get_frame_saved_regs (frame, &fsr); | |
c5aa993b | 622 | for (regnum = 0; regnum < NUM_REGS; regnum++) |
c906108c SS |
623 | { |
624 | CORE_ADDR adr; | |
625 | adr = fsr.regs[regnum]; | |
626 | if (adr) | |
627 | { | |
628 | read_memory (adr, regbuf, REGISTER_RAW_SIZE (regnum)); | |
629 | write_register_bytes (REGISTER_BYTE (regnum), regbuf, | |
630 | REGISTER_RAW_SIZE (regnum)); | |
631 | } | |
632 | } | |
633 | write_register (FP_REGNUM, read_memory_integer (fp, 4)); | |
634 | write_register (PC_REGNUM, read_memory_integer (fp + 4, 4)); | |
635 | write_register (SP_REGNUM, fp + 8); | |
636 | flush_cached_frames (); | |
637 | } | |
638 | ||
639 | #ifdef GET_LONGJMP_TARGET | |
640 | ||
641 | /* Figure out where the longjmp will land. Slurp the args out of the stack. | |
642 | We expect the first arg to be a pointer to the jmp_buf structure from which | |
643 | we extract the pc (JB_PC) that we will land at. The pc is copied into PC. | |
644 | This routine returns true on success. */ | |
645 | ||
646 | int | |
c5aa993b | 647 | get_longjmp_target (pc) |
c906108c SS |
648 | CORE_ADDR *pc; |
649 | { | |
650 | char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT]; | |
651 | CORE_ADDR sp, jb_addr; | |
652 | ||
653 | sp = read_register (SP_REGNUM); | |
654 | ||
c5aa993b | 655 | if (target_read_memory (sp + SP_ARG0, /* Offset of first arg on stack */ |
c906108c SS |
656 | buf, |
657 | TARGET_PTR_BIT / TARGET_CHAR_BIT)) | |
658 | return 0; | |
659 | ||
660 | jb_addr = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT); | |
661 | ||
662 | if (target_read_memory (jb_addr + JB_PC * JB_ELEMENT_SIZE, buf, | |
663 | TARGET_PTR_BIT / TARGET_CHAR_BIT)) | |
664 | return 0; | |
665 | ||
666 | *pc = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT); | |
667 | ||
668 | return 1; | |
669 | } | |
670 | ||
671 | #endif /* GET_LONGJMP_TARGET */ | |
672 | ||
673 | void | |
c5aa993b | 674 | i386_extract_return_value (type, regbuf, valbuf) |
c906108c SS |
675 | struct type *type; |
676 | char regbuf[REGISTER_BYTES]; | |
677 | char *valbuf; | |
678 | { | |
d4f3574e SS |
679 | /* On AIX and i386 GNU/Linux, floating point values are returned in |
680 | floating point registers. */ | |
681 | #if defined(I386_AIX_TARGET) || defined(I386_GNULINUX_TARGET) | |
c5aa993b | 682 | if (TYPE_CODE_FLT == TYPE_CODE (type)) |
c906108c SS |
683 | { |
684 | double d; | |
685 | /* 387 %st(0), gcc uses this */ | |
686 | floatformat_to_double (&floatformat_i387_ext, | |
c2c6d25f JM |
687 | #if defined(FPDATA_REGNUM) |
688 | ®buf[REGISTER_BYTE (FPDATA_REGNUM)], | |
689 | #else /* !FPDATA_REGNUM */ | |
690 | ®buf[REGISTER_BYTE (FP0_REGNUM)], | |
691 | #endif /* FPDATA_REGNUM */ | |
692 | ||
c906108c SS |
693 | &d); |
694 | store_floating (valbuf, TYPE_LENGTH (type), d); | |
695 | } | |
696 | else | |
d4f3574e | 697 | #endif /* I386_AIX_TARGET || I386_GNULINUX_TARGET*/ |
c5aa993b | 698 | { |
c2c6d25f | 699 | #if defined(LOW_RETURN_REGNUM) |
d4f3574e SS |
700 | int len = TYPE_LENGTH (type); |
701 | int low_size = REGISTER_RAW_SIZE (LOW_RETURN_REGNUM); | |
702 | int high_size = REGISTER_RAW_SIZE (HIGH_RETURN_REGNUM); | |
703 | ||
704 | if (len <= low_size) | |
705 | memcpy (valbuf, regbuf + REGISTER_BYTE (LOW_RETURN_REGNUM), len); | |
706 | else if (len <= (low_size + high_size)) | |
707 | { | |
708 | memcpy (valbuf, | |
709 | regbuf + REGISTER_BYTE (LOW_RETURN_REGNUM), | |
710 | low_size); | |
711 | memcpy (valbuf + low_size, | |
712 | regbuf + REGISTER_BYTE (HIGH_RETURN_REGNUM), | |
713 | len - low_size); | |
714 | } | |
715 | else | |
716 | error ("GDB bug: i386-tdep.c (i386_extract_return_value): Don't know how to find a return value %d bytes long", len); | |
c2c6d25f JM |
717 | #else /* !LOW_RETURN_REGNUM */ |
718 | memcpy (valbuf, regbuf, TYPE_LENGTH (type)); | |
719 | #endif /* LOW_RETURN_REGNUM */ | |
c906108c SS |
720 | } |
721 | } | |
722 | ||
723 | #ifdef I386V4_SIGTRAMP_SAVED_PC | |
724 | /* Get saved user PC for sigtramp from the pushed ucontext on the stack | |
725 | for all three variants of SVR4 sigtramps. */ | |
726 | ||
727 | CORE_ADDR | |
728 | i386v4_sigtramp_saved_pc (frame) | |
729 | struct frame_info *frame; | |
730 | { | |
731 | CORE_ADDR saved_pc_offset = 4; | |
732 | char *name = NULL; | |
733 | ||
734 | find_pc_partial_function (frame->pc, &name, NULL, NULL); | |
735 | if (name) | |
736 | { | |
737 | if (STREQ (name, "_sigreturn")) | |
738 | saved_pc_offset = 132 + 14 * 4; | |
739 | else if (STREQ (name, "_sigacthandler")) | |
740 | saved_pc_offset = 80 + 14 * 4; | |
741 | else if (STREQ (name, "sigvechandler")) | |
742 | saved_pc_offset = 120 + 14 * 4; | |
743 | } | |
744 | ||
745 | if (frame->next) | |
746 | return read_memory_integer (frame->next->frame + saved_pc_offset, 4); | |
747 | return read_memory_integer (read_register (SP_REGNUM) + saved_pc_offset, 4); | |
748 | } | |
749 | #endif /* I386V4_SIGTRAMP_SAVED_PC */ | |
750 | ||
a0b3c4fd JM |
751 | #ifdef I386_LINUX_SIGTRAMP |
752 | ||
753 | /* When the i386 Linux kernel calls a signal handler, the return | |
754 | address points to a bit of code on the stack. This function | |
755 | returns whether the PC appears to be within this bit of code. | |
756 | ||
757 | The instruction sequence is | |
758 | pop %eax | |
759 | mov $0x77,%eax | |
760 | int $0x80 | |
761 | or 0x58 0xb8 0x77 0x00 0x00 0x00 0xcd 0x80. | |
762 | ||
763 | Checking for the code sequence should be somewhat reliable, because | |
764 | the effect is to call the system call sigreturn. This is unlikely | |
765 | to occur anywhere other than a signal trampoline. | |
766 | ||
767 | It kind of sucks that we have to read memory from the process in | |
768 | order to identify a signal trampoline, but there doesn't seem to be | |
769 | any other way. The IN_SIGTRAMP macro in tm-linux.h arranges to | |
770 | only call us if no function name could be identified, which should | |
771 | be the case since the code is on the stack. */ | |
772 | ||
773 | #define LINUX_SIGTRAMP_INSN0 (0x58) /* pop %eax */ | |
774 | #define LINUX_SIGTRAMP_OFFSET0 (0) | |
775 | #define LINUX_SIGTRAMP_INSN1 (0xb8) /* mov $NNNN,%eax */ | |
776 | #define LINUX_SIGTRAMP_OFFSET1 (1) | |
777 | #define LINUX_SIGTRAMP_INSN2 (0xcd) /* int */ | |
778 | #define LINUX_SIGTRAMP_OFFSET2 (6) | |
779 | ||
780 | static const unsigned char linux_sigtramp_code[] = | |
781 | { | |
782 | LINUX_SIGTRAMP_INSN0, /* pop %eax */ | |
783 | LINUX_SIGTRAMP_INSN1, 0x77, 0x00, 0x00, 0x00, /* mov $0x77,%eax */ | |
784 | LINUX_SIGTRAMP_INSN2, 0x80 /* int $0x80 */ | |
785 | }; | |
786 | ||
787 | #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) | |
788 | ||
789 | /* If PC is in a sigtramp routine, return the address of the start of | |
790 | the routine. Otherwise, return 0. */ | |
791 | ||
792 | static CORE_ADDR | |
793 | i386_linux_sigtramp_start (pc) | |
794 | CORE_ADDR pc; | |
795 | { | |
796 | unsigned char buf[LINUX_SIGTRAMP_LEN]; | |
797 | ||
798 | /* We only recognize a signal trampoline if PC is at the start of | |
799 | one of the three instructions. We optimize for finding the PC at | |
800 | the start, as will be the case when the trampoline is not the | |
801 | first frame on the stack. We assume that in the case where the | |
802 | PC is not at the start of the instruction sequence, there will be | |
803 | a few trailing readable bytes on the stack. */ | |
804 | ||
805 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) | |
806 | return 0; | |
807 | ||
808 | if (buf[0] != LINUX_SIGTRAMP_INSN0) | |
809 | { | |
810 | int adjust; | |
811 | ||
812 | switch (buf[0]) | |
813 | { | |
814 | case LINUX_SIGTRAMP_INSN1: | |
815 | adjust = LINUX_SIGTRAMP_OFFSET1; | |
816 | break; | |
817 | case LINUX_SIGTRAMP_INSN2: | |
818 | adjust = LINUX_SIGTRAMP_OFFSET2; | |
819 | break; | |
820 | default: | |
821 | return 0; | |
822 | } | |
823 | ||
824 | pc -= adjust; | |
825 | ||
826 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) | |
827 | return 0; | |
828 | } | |
829 | ||
830 | if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0) | |
831 | return 0; | |
832 | ||
833 | return pc; | |
834 | } | |
835 | ||
836 | /* Return whether PC is in a Linux sigtramp routine. */ | |
837 | ||
838 | int | |
839 | i386_linux_sigtramp (pc) | |
840 | CORE_ADDR pc; | |
841 | { | |
842 | return i386_linux_sigtramp_start (pc) != 0; | |
843 | } | |
844 | ||
845 | /* Assuming FRAME is for a Linux sigtramp routine, return the saved | |
846 | program counter. The Linux kernel will set up a sigcontext | |
847 | structure immediately before the sigtramp routine on the stack. */ | |
848 | ||
849 | CORE_ADDR | |
850 | i386_linux_sigtramp_saved_pc (frame) | |
851 | struct frame_info *frame; | |
852 | { | |
853 | CORE_ADDR pc; | |
854 | ||
855 | pc = i386_linux_sigtramp_start (frame->pc); | |
856 | if (pc == 0) | |
857 | error ("i386_linux_sigtramp_saved_pc called when no sigtramp"); | |
858 | return read_memory_integer ((pc | |
859 | - LINUX_SIGCONTEXT_SIZE | |
860 | + LINUX_SIGCONTEXT_PC_OFFSET), | |
861 | 4); | |
862 | } | |
863 | ||
864 | /* Assuming FRAME is for a Linux sigtramp routine, return the saved | |
865 | stack pointer. The Linux kernel will set up a sigcontext structure | |
866 | immediately before the sigtramp routine on the stack. */ | |
867 | ||
868 | CORE_ADDR | |
869 | i386_linux_sigtramp_saved_sp (frame) | |
870 | struct frame_info *frame; | |
871 | { | |
872 | CORE_ADDR pc; | |
873 | ||
874 | pc = i386_linux_sigtramp_start (frame->pc); | |
875 | if (pc == 0) | |
876 | error ("i386_linux_sigtramp_saved_sp called when no sigtramp"); | |
877 | return read_memory_integer ((pc | |
878 | - LINUX_SIGCONTEXT_SIZE | |
879 | + LINUX_SIGCONTEXT_SP_OFFSET), | |
880 | 4); | |
881 | } | |
882 | ||
883 | #endif /* I386_LINUX_SIGTRAMP */ | |
884 | ||
c906108c SS |
885 | #ifdef STATIC_TRANSFORM_NAME |
886 | /* SunPRO encodes the static variables. This is not related to C++ mangling, | |
887 | it is done for C too. */ | |
888 | ||
889 | char * | |
890 | sunpro_static_transform_name (name) | |
891 | char *name; | |
892 | { | |
893 | char *p; | |
894 | if (IS_STATIC_TRANSFORM_NAME (name)) | |
895 | { | |
896 | /* For file-local statics there will be a period, a bunch | |
c5aa993b JM |
897 | of junk (the contents of which match a string given in the |
898 | N_OPT), a period and the name. For function-local statics | |
899 | there will be a bunch of junk (which seems to change the | |
900 | second character from 'A' to 'B'), a period, the name of the | |
901 | function, and the name. So just skip everything before the | |
902 | last period. */ | |
c906108c SS |
903 | p = strrchr (name, '.'); |
904 | if (p != NULL) | |
905 | name = p + 1; | |
906 | } | |
907 | return name; | |
908 | } | |
909 | #endif /* STATIC_TRANSFORM_NAME */ | |
910 | ||
911 | ||
912 | ||
913 | /* Stuff for WIN32 PE style DLL's but is pretty generic really. */ | |
914 | ||
915 | CORE_ADDR | |
916 | skip_trampoline_code (pc, name) | |
917 | CORE_ADDR pc; | |
918 | char *name; | |
919 | { | |
c5aa993b | 920 | if (pc && read_memory_unsigned_integer (pc, 2) == 0x25ff) /* jmp *(dest) */ |
c906108c | 921 | { |
c5aa993b | 922 | unsigned long indirect = read_memory_unsigned_integer (pc + 2, 4); |
c906108c | 923 | struct minimal_symbol *indsym = |
c5aa993b JM |
924 | indirect ? lookup_minimal_symbol_by_pc (indirect) : 0; |
925 | char *symname = indsym ? SYMBOL_NAME (indsym) : 0; | |
c906108c | 926 | |
c5aa993b | 927 | if (symname) |
c906108c | 928 | { |
c5aa993b JM |
929 | if (strncmp (symname, "__imp_", 6) == 0 |
930 | || strncmp (symname, "_imp_", 5) == 0) | |
c906108c SS |
931 | return name ? 1 : read_memory_unsigned_integer (indirect, 4); |
932 | } | |
933 | } | |
934 | return 0; /* not a trampoline */ | |
935 | } | |
936 | ||
937 | static int | |
938 | gdb_print_insn_i386 (memaddr, info) | |
939 | bfd_vma memaddr; | |
c5aa993b | 940 | disassemble_info *info; |
c906108c SS |
941 | { |
942 | if (disassembly_flavor == att_flavor) | |
943 | return print_insn_i386_att (memaddr, info); | |
944 | else if (disassembly_flavor == intel_flavor) | |
945 | return print_insn_i386_intel (memaddr, info); | |
7a292a7a SS |
946 | /* Never reached - disassembly_flavour is always either att_flavor |
947 | or intel_flavor */ | |
948 | abort (); | |
949 | } | |
950 | ||
951 | /* If the disassembly mode is intel, we have to also switch the | |
952 | bfd mach_type. This function is run in the set disassembly_flavor | |
953 | command, and does that. */ | |
954 | ||
955 | static void | |
956 | set_disassembly_flavor_sfunc (args, from_tty, c) | |
957 | char *args; | |
958 | int from_tty; | |
959 | struct cmd_list_element *c; | |
960 | { | |
961 | set_disassembly_flavor (); | |
7a292a7a SS |
962 | } |
963 | ||
964 | static void | |
965 | set_disassembly_flavor () | |
966 | { | |
967 | if (disassembly_flavor == att_flavor) | |
968 | set_architecture_from_arch_mach (bfd_arch_i386, bfd_mach_i386_i386); | |
969 | else if (disassembly_flavor == intel_flavor) | |
970 | set_architecture_from_arch_mach (bfd_arch_i386, bfd_mach_i386_i386_intel_syntax); | |
c906108c SS |
971 | } |
972 | ||
973 | void | |
974 | _initialize_i386_tdep () | |
975 | { | |
7a292a7a | 976 | struct cmd_list_element *new_cmd; |
c5aa993b | 977 | |
c906108c SS |
978 | tm_print_insn = gdb_print_insn_i386; |
979 | tm_print_insn_info.mach = bfd_lookup_arch (bfd_arch_i386, 0)->mach; | |
980 | ||
981 | /* Add the variable that controls the disassembly flavor */ | |
7a292a7a SS |
982 | |
983 | new_cmd = add_set_enum_cmd ("disassembly-flavor", no_class, | |
c5aa993b JM |
984 | valid_flavors, |
985 | (char *) &disassembly_flavor, | |
986 | "Set the disassembly flavor, the valid values are \"att\" and \"intel\", \ | |
c906108c | 987 | and the default value is \"att\".", |
c5aa993b | 988 | &setlist); |
7a292a7a | 989 | new_cmd->function.sfunc = set_disassembly_flavor_sfunc; |
c5aa993b JM |
990 | add_show_from_set (new_cmd, &showlist); |
991 | ||
7a292a7a SS |
992 | /* Finally, initialize the disassembly flavor to the default given |
993 | in the disassembly_flavor variable */ | |
c906108c | 994 | |
7a292a7a | 995 | set_disassembly_flavor (); |
c5aa993b | 996 | |
c906108c | 997 | } |