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
69
70
71
72
73
74
75
76
77
|
// XFAIL:*
//// Suboptimal coverage, see description below.
// REQUIRES: lldb
// UNSUPPORTED: system-windows
// RUN: %dexter --fail-lt 1.0 -w --debugger lldb \
// RUN: --builder 'clang-c' --cflags "-O3 -glldb" -- %s
//// Adapted from https://bugs.llvm.org/show_bug.cgi?id=34136#c1
//// LowerDbgDeclare has since been updated to look through bitcasts. We still
//// get suboptimal coverage at the beginning of 'main' though. For each local,
//// LowerDbgDeclare inserts a dbg.value and a dbg.value+DW_OP_deref before the
//// store (after the call to 'getint') and the call to 'alias' respectively.
//// The first dbg.value describes the result of the 'getint' call, eventually
//// becoming a register location. The second points back into the stack
//// home. There is a gap in the coverage between the quickly clobbered register
//// location and the stack location, even though the stack location is valid
//// during that gap. For x86 we end up with this code at the start of main:
//// 00000000004004b0 <main>:
//// 4004b0: sub rsp,0x18
//// 4004b4: mov edi,0x5
//// 4004b9: call 400480 <getint>
//// 4004be: mov DWORD PTR [rsp+0x14],eax
//// 4004c2: mov edi,0x5
//// 4004c7: call 400480 <getint>
//// 4004cc: mov DWORD PTR [rsp+0x10],eax
//// 4004d0: mov edi,0x5
//// 4004d5: call 400480 <getint>
//// 4004da: mov DWORD PTR [rsp+0xc],eax
//// ...
//// With these variable locations:
//// DW_TAG_variable
//// DW_AT_location (0x00000000:
//// [0x00000000004004be, 0x00000000004004cc): DW_OP_reg0 RAX
//// [0x00000000004004de, 0x0000000000400503): DW_OP_breg7 RSP+20)
//// DW_AT_name ("x")
//// ...
//// DW_TAG_variable
//// DW_AT_location (0x00000037:
//// [0x00000000004004cc, 0x00000000004004da): DW_OP_reg0 RAX
//// [0x00000000004004e8, 0x0000000000400503): DW_OP_breg7 RSP+16)
//// DW_AT_name ("y")
//// ...
//// DW_TAG_variable
//// DW_AT_location (0x0000006e:
//// [0x00000000004004da, 0x00000000004004e8): DW_OP_reg0 RAX
//// [0x00000000004004f2, 0x0000000000400503): DW_OP_breg7 RSP+12)
//// DW_AT_name ("z")
//// ...
char g = 1;
int five = 5;
__attribute__((__noinline__))
int getint(int x) {
g = x - 4;
return x * g;
}
__attribute__((__noinline__))
void alias(char* c) {
g = *c;
*c = (char)five;
}
int main() {
int x = getint(5);
int y = getint(5); // DexLabel('s1')
int z = getint(5); // DexLabel('s2')
alias((char*)&x); // DexLabel('s3')
alias((char*)&y);
alias((char*)&z);
return 0; // DexLabel('s4')
}
// DexExpectWatchValue('x', '5', from_line=ref('s1'), to_line=ref('s4'))
// DexExpectWatchValue('y', '5', from_line=ref('s2'), to_line=ref('s4'))
// DexExpectWatchValue('z', '5', from_line=ref('s3'), to_line=ref('s4'))
|
