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
158
159
|
#pragma once
#include <cstdint>
#include <cstring>
#include <utility>
#include <torch/csrc/profiler/unwind/dwarf_enums.h>
#include <torch/csrc/profiler/unwind/unwind_error.h>
namespace torch::unwind {
template <bool checked>
struct LexerImpl {
LexerImpl(void* data, void* base = nullptr, void* end = nullptr)
: next_((const char*)data),
base_((int64_t)base),
end_((const char*)end) {}
template <typename T>
T read() {
T result;
auto end = next_ + sizeof(T);
UNWIND_CHECK(
!checked || end <= end_,
"read out of bounds {} >= {}",
(void*)end,
(void*)end_);
memcpy(&result, next_, sizeof(T));
next_ = end;
return result;
}
// SLEB/ULEB code adapted from LLVM equivalents
int64_t readSLEB128() {
int64_t Value = 0;
unsigned Shift = 0;
uint8_t Byte = 0;
do {
Byte = read<uint8_t>();
uint64_t Slice = Byte & 0x7f;
if ((Shift >= 64 && Slice != (Value < 0 ? 0x7f : 0x00)) ||
(Shift == 63 && Slice != 0 && Slice != 0x7f)) {
throw UnwindError("sleb128 too big for int64");
}
Value |= int64_t(Slice << Shift);
Shift += 7;
} while (Byte >= 128);
// Sign extend negative numbers if needed.
if (Shift < 64 && (Byte & 0x40)) {
Value |= int64_t((-1ULL) << Shift);
}
return Value;
}
uint64_t readULEB128() {
uint64_t Value = 0;
unsigned Shift = 0;
uint8_t p = 0;
do {
p = read<uint8_t>();
uint64_t Slice = p & 0x7f;
if ((Shift >= 64 && Slice != 0) || Slice << Shift >> Shift != Slice) {
throw UnwindError("uleb128 too big for uint64");
}
Value += Slice << Shift;
Shift += 7;
} while (p >= 128);
return Value;
}
const char* readCString() {
auto result = next_;
if (!checked) {
next_ += strlen(next_) + 1;
return result;
}
while (next_ < end_) {
if (*next_++ == '\0') {
return result;
}
}
UNWIND_CHECK(
false, "string is out of bounds {} >= {}", (void*)next_, (void*)end_);
}
int64_t readEncoded(uint8_t enc) {
int64_t r = 0;
switch (enc & (~DW_EH_PE_indirect & 0xF0)) {
case DW_EH_PE_absptr:
break;
case DW_EH_PE_pcrel:
r = (int64_t)next_;
break;
case DW_EH_PE_datarel:
r = base_;
break;
default:
throw UnwindError("unknown encoding");
}
return r + readEncodedValue(enc);
}
int64_t readEncodedOr(uint8_t enc, int64_t orelse) {
if (enc == DW_EH_PE_omit) {
return orelse;
}
return readEncoded(enc);
}
int64_t read4or8Length() {
return readSectionLength().first;
}
std::pair<int64_t, bool> readSectionLength() {
int64_t length = read<uint32_t>();
if (length == 0xFFFFFFFF) {
return std::make_pair(read<int64_t>(), true);
}
return std::make_pair(length, false);
}
void* loc() const {
return (void*)next_;
}
LexerImpl& skip(size_t bytes) {
next_ += bytes;
return *this;
}
int64_t readEncodedValue(uint8_t enc) {
switch (enc & 0xF) {
case DW_EH_PE_udata2:
return read<uint16_t>();
case DW_EH_PE_sdata2:
return read<int16_t>();
case DW_EH_PE_udata4:
return read<uint32_t>();
case DW_EH_PE_sdata4:
return read<int32_t>();
case DW_EH_PE_udata8:
return read<uint64_t>();
case DW_EH_PE_sdata8:
return read<int64_t>();
case DW_EH_PE_uleb128:
return readULEB128();
case DW_EH_PE_sleb128:
return readSLEB128();
default:
throw UnwindError("not implemented");
}
}
private:
const char* next_;
int64_t base_;
const char* end_;
};
// using Lexer = LexerImpl<false>;
using CheckedLexer = LexerImpl<true>;
using Lexer = LexerImpl<false>;
} // namespace torch::unwind
|
