1 /* Intel 386 target-dependent stuff.
2 Copyright (C) 1988, 1989, 1991, 1994, 1995, 1996, 1998
3 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
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. */
23 #include "gdb_string.h"
28 #include "floatformat.h"
33 static long i386_get_frame_setup
PARAMS ((CORE_ADDR
));
35 static void i386_follow_jump
PARAMS ((void));
37 static void codestream_read
PARAMS ((unsigned char *, int));
39 static void codestream_seek
PARAMS ((CORE_ADDR
));
41 static unsigned char codestream_fill
PARAMS ((int));
43 CORE_ADDR skip_trampoline_code
PARAMS ((CORE_ADDR
, char *));
45 static int gdb_print_insn_i386 (bfd_vma
, disassemble_info
*);
47 void _initialize_i386_tdep
PARAMS ((void));
49 /* i386_register_byte[i] is the offset into the register file of the
50 start of register number i. We initialize this from
51 i386_register_raw_size. */
52 int i386_register_byte
[MAX_NUM_REGS
];
54 /* i386_register_raw_size[i] is the number of bytes of storage in
55 GDB's register array occupied by register i. */
56 int i386_register_raw_size
[MAX_NUM_REGS
] = {
70 /* i386_register_virtual_size[i] is the size in bytes of the virtual
71 type of register i. */
72 int i386_register_virtual_size
[MAX_NUM_REGS
];
75 /* This is the variable the is set with "set disassembly-flavor",
76 and its legitimate values. */
77 static char att_flavor
[] = "att";
78 static char intel_flavor
[] = "intel";
79 static char *valid_flavors
[] =
85 static char *disassembly_flavor
= att_flavor
;
87 static void i386_print_register
PARAMS ((char *, int, int));
89 /* This is used to keep the bfd arch_info in sync with the disassembly flavor. */
90 static void set_disassembly_flavor_sfunc
PARAMS ((char *, int, struct cmd_list_element
*));
91 static void set_disassembly_flavor
PARAMS ((void));
93 /* Stdio style buffering was used to minimize calls to ptrace, but this
94 buffering did not take into account that the code section being accessed
95 may not be an even number of buffers long (even if the buffer is only
96 sizeof(int) long). In cases where the code section size happened to
97 be a non-integral number of buffers long, attempting to read the last
98 buffer would fail. Simply using target_read_memory and ignoring errors,
99 rather than read_memory, is not the correct solution, since legitimate
100 access errors would then be totally ignored. To properly handle this
101 situation and continue to use buffering would require that this code
102 be able to determine the minimum code section size granularity (not the
103 alignment of the section itself, since the actual failing case that
104 pointed out this problem had a section alignment of 4 but was not a
105 multiple of 4 bytes long), on a target by target basis, and then
106 adjust it's buffer size accordingly. This is messy, but potentially
107 feasible. It probably needs the bfd library's help and support. For
108 now, the buffer size is set to 1. (FIXME -fnf) */
110 #define CODESTREAM_BUFSIZ 1 /* Was sizeof(int), see note above. */
111 static CORE_ADDR codestream_next_addr
;
112 static CORE_ADDR codestream_addr
;
113 static unsigned char codestream_buf
[CODESTREAM_BUFSIZ
];
114 static int codestream_off
;
115 static int codestream_cnt
;
117 #define codestream_tell() (codestream_addr + codestream_off)
118 #define codestream_peek() (codestream_cnt == 0 ? \
119 codestream_fill(1): codestream_buf[codestream_off])
120 #define codestream_get() (codestream_cnt-- == 0 ? \
121 codestream_fill(0) : codestream_buf[codestream_off++])
124 codestream_fill (peek_flag
)
127 codestream_addr
= codestream_next_addr
;
128 codestream_next_addr
+= CODESTREAM_BUFSIZ
;
130 codestream_cnt
= CODESTREAM_BUFSIZ
;
131 read_memory (codestream_addr
, (char *) codestream_buf
, CODESTREAM_BUFSIZ
);
134 return (codestream_peek ());
136 return (codestream_get ());
140 codestream_seek (place
)
143 codestream_next_addr
= place
/ CODESTREAM_BUFSIZ
;
144 codestream_next_addr
*= CODESTREAM_BUFSIZ
;
147 while (codestream_tell () != place
)
152 codestream_read (buf
, count
)
159 for (i
= 0; i
< count
; i
++)
160 *p
++ = codestream_get ();
163 /* next instruction is a jump, move to target */
168 unsigned char buf
[4];
174 pos
= codestream_tell ();
177 if (codestream_peek () == 0x66)
183 switch (codestream_get ())
186 /* relative jump: if data16 == 0, disp32, else disp16 */
189 codestream_read (buf
, 2);
190 delta
= extract_signed_integer (buf
, 2);
192 /* include size of jmp inst (including the 0x66 prefix). */
197 codestream_read (buf
, 4);
198 delta
= extract_signed_integer (buf
, 4);
204 /* relative jump, disp8 (ignore data16) */
205 codestream_read (buf
, 1);
206 /* Sign-extend it. */
207 delta
= extract_signed_integer (buf
, 1);
212 codestream_seek (pos
);
216 * find & return amound a local space allocated, and advance codestream to
217 * first register push (if any)
219 * if entry sequence doesn't make sense, return -1, and leave
220 * codestream pointer random
224 i386_get_frame_setup (pc
)
229 codestream_seek (pc
);
233 op
= codestream_get ();
235 if (op
== 0x58) /* popl %eax */
238 * this function must start with
241 * xchgl %eax, (%esp) 0x87 0x04 0x24
242 * or xchgl %eax, 0(%esp) 0x87 0x44 0x24 0x00
244 * (the system 5 compiler puts out the second xchg
245 * inst, and the assembler doesn't try to optimize it,
246 * so the 'sib' form gets generated)
248 * this sequence is used to get the address of the return
249 * buffer for a function that returns a structure
252 unsigned char buf
[4];
253 static unsigned char proto1
[3] =
255 static unsigned char proto2
[4] =
256 {0x87, 0x44, 0x24, 0x00};
257 pos
= codestream_tell ();
258 codestream_read (buf
, 4);
259 if (memcmp (buf
, proto1
, 3) == 0)
261 else if (memcmp (buf
, proto2
, 4) == 0)
264 codestream_seek (pos
);
265 op
= codestream_get (); /* update next opcode */
268 if (op
== 0x68 || op
== 0x6a)
271 * this function may start with
281 unsigned char buf
[8];
283 /* Skip past the pushl instruction; it has either a one-byte
284 or a four-byte operand, depending on the opcode. */
285 pos
= codestream_tell ();
290 codestream_seek (pos
);
292 /* Read the following 8 bytes, which should be "call _probe" (6 bytes)
293 followed by "addl $4,%esp" (2 bytes). */
294 codestream_read (buf
, sizeof (buf
));
295 if (buf
[0] == 0xe8 && buf
[6] == 0xc4 && buf
[7] == 0x4)
297 codestream_seek (pos
);
298 op
= codestream_get (); /* update next opcode */
301 if (op
== 0x55) /* pushl %ebp */
303 /* check for movl %esp, %ebp - can be written two ways */
304 switch (codestream_get ())
307 if (codestream_get () != 0xec)
311 if (codestream_get () != 0xe5)
317 /* check for stack adjustment
321 * note: you can't subtract a 16 bit immediate
322 * from a 32 bit reg, so we don't have to worry
323 * about a data16 prefix
325 op
= codestream_peek ();
328 /* subl with 8 bit immed */
330 if (codestream_get () != 0xec)
331 /* Some instruction starting with 0x83 other than subl. */
333 codestream_seek (codestream_tell () - 2);
336 /* subl with signed byte immediate
337 * (though it wouldn't make sense to be negative)
339 return (codestream_get ());
344 /* Maybe it is subl with 32 bit immedediate. */
346 if (codestream_get () != 0xec)
347 /* Some instruction starting with 0x81 other than subl. */
349 codestream_seek (codestream_tell () - 2);
352 /* It is subl with 32 bit immediate. */
353 codestream_read ((unsigned char *) buf
, 4);
354 return extract_signed_integer (buf
, 4);
364 /* enter instruction: arg is 16 bit unsigned immed */
365 codestream_read ((unsigned char *) buf
, 2);
366 codestream_get (); /* flush final byte of enter instruction */
367 return extract_unsigned_integer (buf
, 2);
372 /* Return number of args passed to a frame.
373 Can return -1, meaning no way to tell. */
376 i386_frame_num_args (fi
)
377 struct frame_info
*fi
;
382 /* This loses because not only might the compiler not be popping the
383 args right after the function call, it might be popping args from both
384 this call and a previous one, and we would say there are more args
385 than there really are. */
389 struct frame_info
*pfi
;
391 /* on the 386, the instruction following the call could be:
393 addl $imm, %esp - imm/4 args; imm may be 8 or 32 bits
394 anything else - zero args */
398 frameless
= FRAMELESS_FUNCTION_INVOCATION (fi
);
400 /* In the absence of a frame pointer, GDB doesn't get correct values
401 for nameless arguments. Return -1, so it doesn't print any
402 nameless arguments. */
405 pfi
= get_prev_frame (fi
);
408 /* Note: this can happen if we are looking at the frame for
409 main, because FRAME_CHAIN_VALID won't let us go into
410 start. If we have debugging symbols, that's not really
411 a big deal; it just means it will only show as many arguments
412 to main as are declared. */
418 op
= read_memory_integer (retpc
, 1);
424 op
= read_memory_integer (retpc
+ 1, 1);
426 /* addl $<signed imm 8 bits>, %esp */
427 return (read_memory_integer (retpc
+ 2, 1) & 0xff) / 4;
432 { /* add with 32 bit immediate */
433 op
= read_memory_integer (retpc
+ 1, 1);
435 /* addl $<imm 32>, %esp */
436 return read_memory_integer (retpc
+ 2, 4) / 4;
449 * parse the first few instructions of the function to see
450 * what registers were stored.
452 * We handle these cases:
454 * The startup sequence can be at the start of the function,
455 * or the function can start with a branch to startup code at the end.
457 * %ebp can be set up with either the 'enter' instruction, or
458 * 'pushl %ebp, movl %esp, %ebp' (enter is too slow to be useful,
459 * but was once used in the sys5 compiler)
461 * Local space is allocated just below the saved %ebp by either the
462 * 'enter' instruction, or by 'subl $<size>, %esp'. 'enter' has
463 * a 16 bit unsigned argument for space to allocate, and the
464 * 'addl' instruction could have either a signed byte, or
467 * Next, the registers used by this function are pushed. In
468 * the sys5 compiler they will always be in the order: %edi, %esi, %ebx
469 * (and sometimes a harmless bug causes it to also save but not restore %eax);
470 * however, the code below is willing to see the pushes in any order,
471 * and will handle up to 8 of them.
473 * If the setup sequence is at the end of the function, then the
474 * next instruction will be a branch back to the start.
478 i386_frame_init_saved_regs (fip
)
479 struct frame_info
*fip
;
483 CORE_ADDR dummy_bottom
;
491 frame_saved_regs_zalloc (fip
);
493 /* if frame is the end of a dummy, compute where the
496 dummy_bottom
= fip
->frame
- 4 - REGISTER_BYTES
- CALL_DUMMY_LENGTH
;
498 /* check if the PC is in the stack, in a dummy frame */
499 if (dummy_bottom
<= fip
->pc
&& fip
->pc
<= fip
->frame
)
501 /* all regs were saved by push_call_dummy () */
503 for (i
= 0; i
< NUM_REGS
; i
++)
505 adr
-= REGISTER_RAW_SIZE (i
);
506 fip
->saved_regs
[i
] = adr
;
511 pc
= get_pc_function_start (fip
->pc
);
513 locals
= i386_get_frame_setup (pc
);
517 adr
= fip
->frame
- 4 - locals
;
518 for (i
= 0; i
< 8; i
++)
520 op
= codestream_get ();
521 if (op
< 0x50 || op
> 0x57)
523 #ifdef I386_REGNO_TO_SYMMETRY
524 /* Dynix uses different internal numbering. Ick. */
525 fip
->saved_regs
[I386_REGNO_TO_SYMMETRY (op
- 0x50)] = adr
;
527 fip
->saved_regs
[op
- 0x50] = adr
;
533 fip
->saved_regs
[PC_REGNUM
] = fip
->frame
+ 4;
534 fip
->saved_regs
[FP_REGNUM
] = fip
->frame
;
537 /* return pc of first real instruction */
540 i386_skip_prologue (pc
)
545 static unsigned char pic_pat
[6] =
546 {0xe8, 0, 0, 0, 0, /* call 0x0 */
547 0x5b, /* popl %ebx */
551 if (i386_get_frame_setup (pc
) < 0)
554 /* found valid frame setup - codestream now points to
555 * start of push instructions for saving registers
558 /* skip over register saves */
559 for (i
= 0; i
< 8; i
++)
561 op
= codestream_peek ();
562 /* break if not pushl inst */
563 if (op
< 0x50 || op
> 0x57)
568 /* The native cc on SVR4 in -K PIC mode inserts the following code to get
569 the address of the global offset table (GOT) into register %ebx.
572 movl %ebx,x(%ebp) (optional)
574 This code is with the rest of the prologue (at the end of the
575 function), so we have to skip it to get to the first real
576 instruction at the start of the function. */
578 pos
= codestream_tell ();
579 for (i
= 0; i
< 6; i
++)
581 op
= codestream_get ();
582 if (pic_pat
[i
] != op
)
587 unsigned char buf
[4];
590 op
= codestream_get ();
591 if (op
== 0x89) /* movl %ebx, x(%ebp) */
593 op
= codestream_get ();
594 if (op
== 0x5d) /* one byte offset from %ebp */
597 codestream_read (buf
, 1);
599 else if (op
== 0x9d) /* four byte offset from %ebp */
602 codestream_read (buf
, 4);
604 else /* unexpected instruction */
606 op
= codestream_get ();
609 if (delta
> 0 && op
== 0x81 && codestream_get () == 0xc3)
614 codestream_seek (pos
);
618 return (codestream_tell ());
622 i386_push_dummy_frame ()
624 CORE_ADDR sp
= read_register (SP_REGNUM
);
626 char regbuf
[MAX_REGISTER_RAW_SIZE
];
628 sp
= push_word (sp
, read_register (PC_REGNUM
));
629 sp
= push_word (sp
, read_register (FP_REGNUM
));
630 write_register (FP_REGNUM
, sp
);
631 for (regnum
= 0; regnum
< NUM_REGS
; regnum
++)
633 read_register_gen (regnum
, regbuf
);
634 sp
= push_bytes (sp
, regbuf
, REGISTER_RAW_SIZE (regnum
));
636 write_register (SP_REGNUM
, sp
);
642 struct frame_info
*frame
= get_current_frame ();
645 char regbuf
[MAX_REGISTER_RAW_SIZE
];
647 fp
= FRAME_FP (frame
);
648 i386_frame_init_saved_regs (frame
);
650 for (regnum
= 0; regnum
< NUM_REGS
; regnum
++)
653 adr
= frame
->saved_regs
[regnum
];
656 read_memory (adr
, regbuf
, REGISTER_RAW_SIZE (regnum
));
657 write_register_bytes (REGISTER_BYTE (regnum
), regbuf
,
658 REGISTER_RAW_SIZE (regnum
));
661 write_register (FP_REGNUM
, read_memory_integer (fp
, 4));
662 write_register (PC_REGNUM
, read_memory_integer (fp
+ 4, 4));
663 write_register (SP_REGNUM
, fp
+ 8);
664 flush_cached_frames ();
667 #ifdef GET_LONGJMP_TARGET
669 /* Figure out where the longjmp will land. Slurp the args out of the stack.
670 We expect the first arg to be a pointer to the jmp_buf structure from which
671 we extract the pc (JB_PC) that we will land at. The pc is copied into PC.
672 This routine returns true on success. */
675 get_longjmp_target (pc
)
678 char buf
[TARGET_PTR_BIT
/ TARGET_CHAR_BIT
];
679 CORE_ADDR sp
, jb_addr
;
681 sp
= read_register (SP_REGNUM
);
683 if (target_read_memory (sp
+ SP_ARG0
, /* Offset of first arg on stack */
685 TARGET_PTR_BIT
/ TARGET_CHAR_BIT
))
688 jb_addr
= extract_address (buf
, TARGET_PTR_BIT
/ TARGET_CHAR_BIT
);
690 if (target_read_memory (jb_addr
+ JB_PC
* JB_ELEMENT_SIZE
, buf
,
691 TARGET_PTR_BIT
/ TARGET_CHAR_BIT
))
694 *pc
= extract_address (buf
, TARGET_PTR_BIT
/ TARGET_CHAR_BIT
);
699 #endif /* GET_LONGJMP_TARGET */
702 i386_extract_return_value (type
, regbuf
, valbuf
)
704 char regbuf
[REGISTER_BYTES
];
707 /* On AIX, i386 GNU/Linux and DJGPP, floating point values are
708 returned in floating point registers. */
709 /* FIXME: cagney/2000-02-29: This function needs to be rewritten
710 using multi-arch. Please don't keep adding to this #ifdef
712 #if defined(I386_AIX_TARGET) || defined(I386_GNULINUX_TARGET) || defined(I386_DJGPP_TARGET)
713 if (TYPE_CODE_FLT
== TYPE_CODE (type
))
716 /* 387 %st(0), gcc uses this */
717 floatformat_to_double (&floatformat_i387_ext
,
718 #if defined(FPDATA_REGNUM)
719 ®buf
[REGISTER_BYTE (FPDATA_REGNUM
)],
720 #else /* !FPDATA_REGNUM */
721 ®buf
[REGISTER_BYTE (FP0_REGNUM
)],
722 #endif /* FPDATA_REGNUM */
725 store_floating (valbuf
, TYPE_LENGTH (type
), d
);
728 #endif /* I386_AIX_TARGET || I386_GNULINUX_TARGET || I386_DJGPP_TARGET */
730 #if defined(LOW_RETURN_REGNUM)
731 int len
= TYPE_LENGTH (type
);
732 int low_size
= REGISTER_RAW_SIZE (LOW_RETURN_REGNUM
);
733 int high_size
= REGISTER_RAW_SIZE (HIGH_RETURN_REGNUM
);
736 memcpy (valbuf
, regbuf
+ REGISTER_BYTE (LOW_RETURN_REGNUM
), len
);
737 else if (len
<= (low_size
+ high_size
))
740 regbuf
+ REGISTER_BYTE (LOW_RETURN_REGNUM
),
742 memcpy (valbuf
+ low_size
,
743 regbuf
+ REGISTER_BYTE (HIGH_RETURN_REGNUM
),
747 error ("GDB bug: i386-tdep.c (i386_extract_return_value): Don't know how to find a return value %d bytes long", len
);
748 #else /* !LOW_RETURN_REGNUM */
749 memcpy (valbuf
, regbuf
, TYPE_LENGTH (type
));
750 #endif /* LOW_RETURN_REGNUM */
754 #ifdef I386V4_SIGTRAMP_SAVED_PC
755 /* Get saved user PC for sigtramp from the pushed ucontext on the stack
756 for all three variants of SVR4 sigtramps. */
759 i386v4_sigtramp_saved_pc (frame
)
760 struct frame_info
*frame
;
762 CORE_ADDR saved_pc_offset
= 4;
765 find_pc_partial_function (frame
->pc
, &name
, NULL
, NULL
);
768 if (STREQ (name
, "_sigreturn"))
769 saved_pc_offset
= 132 + 14 * 4;
770 else if (STREQ (name
, "_sigacthandler"))
771 saved_pc_offset
= 80 + 14 * 4;
772 else if (STREQ (name
, "sigvechandler"))
773 saved_pc_offset
= 120 + 14 * 4;
777 return read_memory_integer (frame
->next
->frame
+ saved_pc_offset
, 4);
778 return read_memory_integer (read_register (SP_REGNUM
) + saved_pc_offset
, 4);
780 #endif /* I386V4_SIGTRAMP_SAVED_PC */
782 #ifdef I386_LINUX_SIGTRAMP
784 /* Linux has two flavors of signals. Normal signal handlers, and
785 "realtime" (RT) signals. The RT signals can provide additional
786 information to the signal handler if the SA_SIGINFO flag is set
787 when establishing a signal handler using `sigaction'. It is not
788 unlikely that future versions of Linux will support SA_SIGINFO for
789 normal signals too. */
791 /* When the i386 Linux kernel calls a signal handler and the
792 SA_RESTORER flag isn't set, the return address points to a bit of
793 code on the stack. This function returns whether the PC appears to
794 be within this bit of code.
796 The instruction sequence for normal signals is
800 or 0x58 0xb8 0x77 0x00 0x00 0x00 0xcd 0x80.
802 Checking for the code sequence should be somewhat reliable, because
803 the effect is to call the system call sigreturn. This is unlikely
804 to occur anywhere other than a signal trampoline.
806 It kind of sucks that we have to read memory from the process in
807 order to identify a signal trampoline, but there doesn't seem to be
808 any other way. The IN_SIGTRAMP macro in tm-linux.h arranges to
809 only call us if no function name could be identified, which should
810 be the case since the code is on the stack.
812 Detection of signal trampolines for handlers that set the
813 SA_RESTORER flag is in general not possible. Unfortunately this is
814 what the GNU C Library has been doing for quite some time now.
815 However, as of version 2.1.2, the GNU C Library uses signal
816 trampolines (named __restore and __restore_rt) that are identical
817 to the ones used by the kernel. Therefore, these trampolines are
820 #define LINUX_SIGTRAMP_INSN0 (0x58) /* pop %eax */
821 #define LINUX_SIGTRAMP_OFFSET0 (0)
822 #define LINUX_SIGTRAMP_INSN1 (0xb8) /* mov $NNNN,%eax */
823 #define LINUX_SIGTRAMP_OFFSET1 (1)
824 #define LINUX_SIGTRAMP_INSN2 (0xcd) /* int */
825 #define LINUX_SIGTRAMP_OFFSET2 (6)
827 static const unsigned char linux_sigtramp_code
[] =
829 LINUX_SIGTRAMP_INSN0
, /* pop %eax */
830 LINUX_SIGTRAMP_INSN1
, 0x77, 0x00, 0x00, 0x00, /* mov $0x77,%eax */
831 LINUX_SIGTRAMP_INSN2
, 0x80 /* int $0x80 */
834 #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code)
836 /* If PC is in a sigtramp routine, return the address of the start of
837 the routine. Otherwise, return 0. */
840 i386_linux_sigtramp_start (CORE_ADDR pc
)
842 unsigned char buf
[LINUX_SIGTRAMP_LEN
];
844 /* We only recognize a signal trampoline if PC is at the start of
845 one of the three instructions. We optimize for finding the PC at
846 the start, as will be the case when the trampoline is not the
847 first frame on the stack. We assume that in the case where the
848 PC is not at the start of the instruction sequence, there will be
849 a few trailing readable bytes on the stack. */
851 if (read_memory_nobpt (pc
, (char *) buf
, LINUX_SIGTRAMP_LEN
) != 0)
854 if (buf
[0] != LINUX_SIGTRAMP_INSN0
)
860 case LINUX_SIGTRAMP_INSN1
:
861 adjust
= LINUX_SIGTRAMP_OFFSET1
;
863 case LINUX_SIGTRAMP_INSN2
:
864 adjust
= LINUX_SIGTRAMP_OFFSET2
;
872 if (read_memory_nobpt (pc
, (char *) buf
, LINUX_SIGTRAMP_LEN
) != 0)
876 if (memcmp (buf
, linux_sigtramp_code
, LINUX_SIGTRAMP_LEN
) != 0)
882 /* This function does the same for RT signals. Here the instruction
886 or 0xb8 0xad 0x00 0x00 0x00 0xcd 0x80.
888 The effect is to call the system call rt_sigreturn. */
890 #define LINUX_RT_SIGTRAMP_INSN0 (0xb8) /* mov $NNNN,%eax */
891 #define LINUX_RT_SIGTRAMP_OFFSET0 (0)
892 #define LINUX_RT_SIGTRAMP_INSN1 (0xcd) /* int */
893 #define LINUX_RT_SIGTRAMP_OFFSET1 (5)
895 static const unsigned char linux_rt_sigtramp_code
[] =
897 LINUX_RT_SIGTRAMP_INSN0
, 0xad, 0x00, 0x00, 0x00, /* mov $0xad,%eax */
898 LINUX_RT_SIGTRAMP_INSN1
, 0x80 /* int $0x80 */
901 #define LINUX_RT_SIGTRAMP_LEN (sizeof linux_rt_sigtramp_code)
903 /* If PC is in a RT sigtramp routine, return the address of the start
904 of the routine. Otherwise, return 0. */
907 i386_linux_rt_sigtramp_start (CORE_ADDR pc
)
909 unsigned char buf
[LINUX_RT_SIGTRAMP_LEN
];
911 /* We only recognize a signal trampoline if PC is at the start of
912 one of the two instructions. We optimize for finding the PC at
913 the start, as will be the case when the trampoline is not the
914 first frame on the stack. We assume that in the case where the
915 PC is not at the start of the instruction sequence, there will be
916 a few trailing readable bytes on the stack. */
918 if (read_memory_nobpt (pc
, (char *) buf
, LINUX_RT_SIGTRAMP_LEN
) != 0)
921 if (buf
[0] != LINUX_RT_SIGTRAMP_INSN0
)
923 if (buf
[0] != LINUX_RT_SIGTRAMP_INSN1
)
926 pc
-= LINUX_RT_SIGTRAMP_OFFSET1
;
928 if (read_memory_nobpt (pc
, (char *) buf
, LINUX_RT_SIGTRAMP_LEN
) != 0)
932 if (memcmp (buf
, linux_rt_sigtramp_code
, LINUX_RT_SIGTRAMP_LEN
) != 0)
938 /* Return whether PC is in a Linux sigtramp routine. */
941 i386_linux_in_sigtramp (CORE_ADDR pc
, char *name
)
944 return STREQ ("__restore", name
) || STREQ ("__restore_rt", name
);
946 return (i386_linux_sigtramp_start (pc
) != 0
947 || i386_linux_rt_sigtramp_start (pc
) != 0);
950 /* Assuming FRAME is for a Linux sigtramp routine, return the address
951 of the associated sigcontext structure. */
954 i386_linux_sigcontext_addr (struct frame_info
*frame
)
958 pc
= i386_linux_sigtramp_start (frame
->pc
);
964 /* If this isn't the top frame, the next frame must be for the
965 signal handler itself. The sigcontext structure lives on
966 the stack, right after the signum argument. */
967 return frame
->next
->frame
+ 12;
969 /* This is the top frame. We'll have to find the address of the
970 sigcontext structure by looking at the stack pointer. Keep
971 in mind that the first instruction of the sigtramp code is
972 "pop %eax". If the PC is at this instruction, adjust the
973 returned value accordingly. */
974 sp
= read_register (SP_REGNUM
);
980 pc
= i386_linux_rt_sigtramp_start (frame
->pc
);
984 /* If this isn't the top frame, the next frame must be for the
985 signal handler itself. The sigcontext structure is part of
986 the user context. A pointer to the user context is passed
987 as the third argument to the signal handler. */
988 return read_memory_integer (frame
->next
->frame
+ 16, 4) + 20;
990 /* This is the top frame. Again, use the stack pointer to find
991 the address of the sigcontext structure. */
992 return read_memory_integer (read_register (SP_REGNUM
) + 8, 4) + 20;
995 error ("Couldn't recognize signal trampoline.");
999 /* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */
1000 #define LINUX_SIGCONTEXT_PC_OFFSET (56)
1002 /* Assuming FRAME is for a Linux sigtramp routine, return the saved
1006 i386_linux_sigtramp_saved_pc (struct frame_info
*frame
)
1009 addr
= i386_linux_sigcontext_addr (frame
);
1010 return read_memory_integer (addr
+ LINUX_SIGCONTEXT_PC_OFFSET
, 4);
1013 /* Offset to saved SP in sigcontext, from <asm/sigcontext.h>. */
1014 #define LINUX_SIGCONTEXT_SP_OFFSET (28)
1016 /* Assuming FRAME is for a Linux sigtramp routine, return the saved
1020 i386_linux_sigtramp_saved_sp (struct frame_info
*frame
)
1023 addr
= i386_linux_sigcontext_addr (frame
);
1024 return read_memory_integer (addr
+ LINUX_SIGCONTEXT_SP_OFFSET
, 4);
1027 /* Immediately after a function call, return the saved pc. */
1030 i386_linux_saved_pc_after_call (struct frame_info
*frame
)
1032 if (frame
->signal_handler_caller
)
1033 return i386_linux_sigtramp_saved_pc (frame
);
1035 return read_memory_integer (read_register (SP_REGNUM
), 4);
1038 #endif /* I386_LINUX_SIGTRAMP */
1040 #ifdef STATIC_TRANSFORM_NAME
1041 /* SunPRO encodes the static variables. This is not related to C++ mangling,
1042 it is done for C too. */
1045 sunpro_static_transform_name (name
)
1049 if (IS_STATIC_TRANSFORM_NAME (name
))
1051 /* For file-local statics there will be a period, a bunch
1052 of junk (the contents of which match a string given in the
1053 N_OPT), a period and the name. For function-local statics
1054 there will be a bunch of junk (which seems to change the
1055 second character from 'A' to 'B'), a period, the name of the
1056 function, and the name. So just skip everything before the
1058 p
= strrchr (name
, '.');
1064 #endif /* STATIC_TRANSFORM_NAME */
1068 /* Stuff for WIN32 PE style DLL's but is pretty generic really. */
1071 skip_trampoline_code (pc
, name
)
1075 if (pc
&& read_memory_unsigned_integer (pc
, 2) == 0x25ff) /* jmp *(dest) */
1077 unsigned long indirect
= read_memory_unsigned_integer (pc
+ 2, 4);
1078 struct minimal_symbol
*indsym
=
1079 indirect
? lookup_minimal_symbol_by_pc (indirect
) : 0;
1080 char *symname
= indsym
? SYMBOL_NAME (indsym
) : 0;
1084 if (strncmp (symname
, "__imp_", 6) == 0
1085 || strncmp (symname
, "_imp_", 5) == 0)
1086 return name
? 1 : read_memory_unsigned_integer (indirect
, 4);
1089 return 0; /* not a trampoline */
1093 gdb_print_insn_i386 (memaddr
, info
)
1095 disassemble_info
*info
;
1097 if (disassembly_flavor
== att_flavor
)
1098 return print_insn_i386_att (memaddr
, info
);
1099 else if (disassembly_flavor
== intel_flavor
)
1100 return print_insn_i386_intel (memaddr
, info
);
1101 /* Never reached - disassembly_flavour is always either att_flavor
1106 /* If the disassembly mode is intel, we have to also switch the
1107 bfd mach_type. This function is run in the set disassembly_flavor
1108 command, and does that. */
1111 set_disassembly_flavor_sfunc (args
, from_tty
, c
)
1114 struct cmd_list_element
*c
;
1116 set_disassembly_flavor ();
1120 set_disassembly_flavor ()
1122 if (disassembly_flavor
== att_flavor
)
1123 set_architecture_from_arch_mach (bfd_arch_i386
, bfd_mach_i386_i386
);
1124 else if (disassembly_flavor
== intel_flavor
)
1125 set_architecture_from_arch_mach (bfd_arch_i386
, bfd_mach_i386_i386_intel_syntax
);
1130 _initialize_i386_tdep ()
1132 /* Initialize the table saying where each register starts in the
1138 for (i
= 0; i
< MAX_NUM_REGS
; i
++)
1140 i386_register_byte
[i
] = offset
;
1141 offset
+= i386_register_raw_size
[i
];
1145 /* Initialize the table of virtual register sizes. */
1149 for (i
= 0; i
< MAX_NUM_REGS
; i
++)
1150 i386_register_virtual_size
[i
] = TYPE_LENGTH (REGISTER_VIRTUAL_TYPE (i
));
1153 tm_print_insn
= gdb_print_insn_i386
;
1154 tm_print_insn_info
.mach
= bfd_lookup_arch (bfd_arch_i386
, 0)->mach
;
1156 /* Add the variable that controls the disassembly flavor */
1158 struct cmd_list_element
*new_cmd
;
1160 new_cmd
= add_set_enum_cmd ("disassembly-flavor", no_class
,
1162 (char *) &disassembly_flavor
,
1163 "Set the disassembly flavor, the valid values are \"att\" and \"intel\", \
1164 and the default value is \"att\".",
1166 new_cmd
->function
.sfunc
= set_disassembly_flavor_sfunc
;
1167 add_show_from_set (new_cmd
, &showlist
);
1170 /* Finally, initialize the disassembly flavor to the default given
1171 in the disassembly_flavor variable */
1173 set_disassembly_flavor ();