1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
|
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <libunwind.h>
static int verbose;
static int nerrors;
#define panic(args...) \
do { printf (args); ++nerrors; } while (0)
// Assembly routine which sets up the stack for the test then calls another one
// which clobbers the stack, and which in turn calls recover_register below
extern int64_t DW_CFA_expression_testcase(int64_t regnum, int64_t height);
// recover_register is called by the assembly routines. It returns the value of
// a register at a specified height from the inner-most frame. The return value
// is propagated back through the assembly routines to the testcase.
extern int64_t recover_register(int64_t regnum, int64_t height)
{
// Initialize cursor to current frame
int rc, i;
unw_cursor_t cursor;
unw_context_t context;
unw_getcontext(&context);
unw_init_local(&cursor, &context);
// Unwind frames until required height from inner-most frame (i.e. this one)
for (i = 0; i < height; ++i)
{
rc = unw_step(&cursor);
if (rc < 0)
panic("%s: unw_step failed on step %d with return code %d", __FUNCTION__, i, rc);
else if (rc == 0)
panic("%s: unw_step failed to reach the end of the stack", __FUNCTION__);
unw_word_t pc;
rc = unw_get_reg(&cursor, UNW_REG_IP, &pc);
if (rc < 0 || pc == 0)
panic("%s: unw_get_reg failed to locate the program counter", __FUNCTION__);
}
// We're now at the required height, extract register
uint64_t value;
if ((rc = unw_get_reg(&cursor, (unw_regnum_t) regnum, &value)) != 0)
panic("%s: unw_get_reg failed to retrieve register %lu", __FUNCTION__, regnum);
return value;
}
int
main (int argc, char **argv)
{
if (argc > 1)
verbose = 1;
if (DW_CFA_expression_testcase(12, 1) != 0)
panic("r12 should be clobbered at height 1 (DW_CFA_expression_inner)");
if (DW_CFA_expression_testcase(12, 2) != 111222333)
panic("r12 should be restored at height 2 (DW_CFA_expression_testcase)");
if (nerrors > 0)
{
fprintf (stderr, "FAILURE: detected %d errors\n", nerrors);
exit (-1);
}
if (verbose)
printf ("SUCCESS.\n");
return 0;
}
|
