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d11916aa SS |
1 | /* This test program is part of GDB, the GNU debugger. |
2 | ||
b811d2c2 | 3 | Copyright 2015-2020 Free Software Foundation, Inc. |
d11916aa SS |
4 | |
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | /* This is the test program loaded into GDB by the py-unwind test. */ | |
19 | ||
20 | #include <stdint.h> | |
21 | #include <stdio.h> | |
22 | #include <stdlib.h> | |
23 | ||
24 | static void * | |
25 | swap_value (void **location, void *new_value) | |
26 | { | |
27 | void *old_value = *location; | |
28 | *location = new_value; | |
29 | return old_value; | |
30 | } | |
31 | ||
32 | static void | |
33 | bad_layout(void **variable_ptr, void *fp) | |
34 | { | |
35 | fprintf (stderr, "First variable should be allocated one word below " | |
36 | "the frame. Got variable's address %p, frame at %p instead.\n", | |
37 | variable_ptr, fp); | |
38 | abort(); | |
39 | } | |
40 | ||
41 | #define MY_FRAME (__builtin_frame_address (0)) | |
42 | ||
43 | static void | |
44 | corrupt_frame_inner (void) | |
45 | { | |
46 | /* Save outer frame address, then corrupt the unwind chain by | |
47 | setting the outer frame address in it to self. This is | |
48 | ABI-specific: the first word of the frame contains previous frame | |
49 | address in amd64. */ | |
50 | void *previous_fp = swap_value ((void **) MY_FRAME, MY_FRAME); | |
51 | ||
52 | /* Verify the compiler allocates the first local variable one word | |
53 | below frame. This is where the test unwinder expects to find the | |
54 | correct outer frame address. */ | |
55 | if (&previous_fp + 1 != (void **) MY_FRAME) | |
56 | bad_layout (&previous_fp + 1, MY_FRAME); | |
57 | ||
58 | /* Now restore it so that we can return. The test sets the | |
59 | breakpoint just before this happens, and GDB will not be able to | |
60 | show the backtrace without JIT reader. */ | |
61 | swap_value ((void **) MY_FRAME, previous_fp); /* break backtrace-broken */ | |
62 | } | |
63 | ||
64 | static void | |
65 | corrupt_frame_outer (void) | |
66 | { | |
67 | /* See above for the explanation of the code here. This function | |
68 | corrupts its frame, too, and then calls the inner one. */ | |
69 | void *previous_fp = swap_value ((void **) MY_FRAME, MY_FRAME); | |
70 | if (&previous_fp + 1 != (void **) MY_FRAME) | |
71 | bad_layout (&previous_fp, MY_FRAME); | |
72 | corrupt_frame_inner (); | |
73 | swap_value ((void **) MY_FRAME, previous_fp); | |
74 | } | |
75 | ||
76 | int | |
77 | main () | |
78 | { | |
79 | corrupt_frame_outer (); | |
80 | return 0; | |
81 | } |