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
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
use crate::trampoline::get_libcall_trampoline;
use std::ptr::{read_unaligned, write_unaligned};
use wasmer_compiler::{
JumpTable, JumpTableOffsets, Relocation, RelocationKind, RelocationTarget, Relocations,
SectionIndex,
};
use wasmer_engine::FunctionExtent;
use wasmer_types::entity::{EntityRef, PrimaryMap};
use wasmer_types::{LocalFunctionIndex, ModuleInfo};
use wasmer_vm::SectionBodyPtr;
fn apply_relocation(
body: usize,
r: &Relocation,
allocated_functions: &PrimaryMap<LocalFunctionIndex, FunctionExtent>,
jt_offsets: &PrimaryMap<LocalFunctionIndex, JumpTableOffsets>,
allocated_sections: &PrimaryMap<SectionIndex, SectionBodyPtr>,
libcall_trampolines: SectionIndex,
libcall_trampoline_len: usize,
) {
let target_func_address: usize = match r.reloc_target {
RelocationTarget::LocalFunc(index) => *allocated_functions[index].ptr as usize,
RelocationTarget::LibCall(libcall) => {
if r.kind == RelocationKind::Abs8 || r.kind == RelocationKind::X86PCRel8 {
libcall.function_pointer()
} else {
get_libcall_trampoline(
libcall,
allocated_sections[libcall_trampolines].0 as usize,
libcall_trampoline_len,
)
}
}
RelocationTarget::CustomSection(custom_section) => {
*allocated_sections[custom_section] as usize
}
RelocationTarget::JumpTable(func_index, jt) => {
let offset = *jt_offsets
.get(func_index)
.and_then(|ofs| ofs.get(JumpTable::new(jt.index())))
.expect("func jump table");
*allocated_functions[func_index].ptr as usize + offset as usize
}
};
match r.kind {
#[cfg(target_pointer_width = "64")]
RelocationKind::Abs8 => unsafe {
let (reloc_address, reloc_delta) = r.for_address(body, target_func_address as u64);
write_unaligned(reloc_address as *mut u64, reloc_delta);
},
#[cfg(target_pointer_width = "32")]
RelocationKind::X86PCRel4 => unsafe {
let (reloc_address, reloc_delta) = r.for_address(body, target_func_address as u64);
write_unaligned(reloc_address as *mut u32, reloc_delta as _);
},
#[cfg(target_pointer_width = "64")]
RelocationKind::X86PCRel8 => unsafe {
let (reloc_address, reloc_delta) = r.for_address(body, target_func_address as u64);
write_unaligned(reloc_address as *mut u64, reloc_delta);
},
RelocationKind::X86CallPCRel4 => unsafe {
let (reloc_address, reloc_delta) = r.for_address(body, target_func_address as u64);
write_unaligned(reloc_address as *mut u32, reloc_delta as _);
},
RelocationKind::X86PCRelRodata4 => {}
RelocationKind::Arm64Call => unsafe {
let (reloc_address, reloc_delta) = r.for_address(body, target_func_address as u64);
if (reloc_delta as i64).abs() >= 0x1000_0000 {
panic!(
"Relocation to big for {:?} for {:?} with {:x}, current val {:x}",
r.kind,
r.reloc_target,
reloc_delta,
read_unaligned(reloc_address as *mut u32)
)
}
let reloc_delta = (((reloc_delta / 4) as u32) & 0x3ff_ffff)
| read_unaligned(reloc_address as *mut u32);
write_unaligned(reloc_address as *mut u32, reloc_delta);
},
RelocationKind::Arm64Movw0 => unsafe {
let (reloc_address, reloc_delta) = r.for_address(body, target_func_address as u64);
let reloc_delta =
(((reloc_delta & 0xffff) as u32) << 5) | read_unaligned(reloc_address as *mut u32);
write_unaligned(reloc_address as *mut u32, reloc_delta);
},
RelocationKind::Arm64Movw1 => unsafe {
let (reloc_address, reloc_delta) = r.for_address(body, target_func_address as u64);
let reloc_delta = ((((reloc_delta >> 16) & 0xffff) as u32) << 5)
| read_unaligned(reloc_address as *mut u32);
write_unaligned(reloc_address as *mut u32, reloc_delta);
},
RelocationKind::Arm64Movw2 => unsafe {
let (reloc_address, reloc_delta) = r.for_address(body, target_func_address as u64);
let reloc_delta = ((((reloc_delta >> 32) & 0xffff) as u32) << 5)
| read_unaligned(reloc_address as *mut u32);
write_unaligned(reloc_address as *mut u32, reloc_delta);
},
RelocationKind::Arm64Movw3 => unsafe {
let (reloc_address, reloc_delta) = r.for_address(body, target_func_address as u64);
let reloc_delta = ((((reloc_delta >> 48) & 0xffff) as u32) << 5)
| read_unaligned(reloc_address as *mut u32);
write_unaligned(reloc_address as *mut u32, reloc_delta);
},
kind => panic!(
"Relocation kind unsupported in the current architecture {}",
kind
),
}
}
pub fn link_module(
_module: &ModuleInfo,
allocated_functions: &PrimaryMap<LocalFunctionIndex, FunctionExtent>,
jt_offsets: &PrimaryMap<LocalFunctionIndex, JumpTableOffsets>,
function_relocations: Relocations,
allocated_sections: &PrimaryMap<SectionIndex, SectionBodyPtr>,
section_relocations: &PrimaryMap<SectionIndex, Vec<Relocation>>,
libcall_trampolines: SectionIndex,
trampoline_len: usize,
) {
for (i, section_relocs) in section_relocations.iter() {
let body = *allocated_sections[i] as usize;
for r in section_relocs {
apply_relocation(
body,
r,
allocated_functions,
jt_offsets,
allocated_sections,
libcall_trampolines,
trampoline_len,
);
}
}
for (i, function_relocs) in function_relocations.iter() {
let body = *allocated_functions[i].ptr as usize;
for r in function_relocs {
apply_relocation(
body,
r,
allocated_functions,
jt_offsets,
allocated_sections,
libcall_trampolines,
trampoline_len,
);
}
}
}
