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
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
|
//===--- RuntimeDyldCOFFI386.h --- COFF/X86_64 specific code ---*- C++ --*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// COFF x86 support for MC-JIT runtime dynamic linker.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFFI386_H
#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDCOFFI386_H
#include "../RuntimeDyldCOFF.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/Object/COFF.h"
#define DEBUG_TYPE "dyld"
namespace llvm {
class RuntimeDyldCOFFI386 : public RuntimeDyldCOFF {
public:
RuntimeDyldCOFFI386(RuntimeDyld::MemoryManager &MM,
JITSymbolResolver &Resolver)
: RuntimeDyldCOFF(MM, Resolver) {}
unsigned getMaxStubSize() const override {
return 8; // 2-byte jmp instruction + 32-bit relative address + 2 byte pad
}
unsigned getStubAlignment() override { return 1; }
Expected<object::relocation_iterator>
processRelocationRef(unsigned SectionID,
object::relocation_iterator RelI,
const object::ObjectFile &Obj,
ObjSectionToIDMap &ObjSectionToID,
StubMap &Stubs) override {
auto Symbol = RelI->getSymbol();
if (Symbol == Obj.symbol_end())
report_fatal_error("Unknown symbol in relocation");
Expected<StringRef> TargetNameOrErr = Symbol->getName();
if (!TargetNameOrErr)
return TargetNameOrErr.takeError();
StringRef TargetName = *TargetNameOrErr;
auto SectionOrErr = Symbol->getSection();
if (!SectionOrErr)
return SectionOrErr.takeError();
auto Section = *SectionOrErr;
uint64_t RelType = RelI->getType();
uint64_t Offset = RelI->getOffset();
// Determine the Addend used to adjust the relocation value.
uint64_t Addend = 0;
SectionEntry &AddendSection = Sections[SectionID];
uintptr_t ObjTarget = AddendSection.getObjAddress() + Offset;
uint8_t *Displacement = (uint8_t *)ObjTarget;
switch (RelType) {
case COFF::IMAGE_REL_I386_DIR32:
case COFF::IMAGE_REL_I386_DIR32NB:
case COFF::IMAGE_REL_I386_SECREL:
case COFF::IMAGE_REL_I386_REL32: {
Addend = readBytesUnaligned(Displacement, 4);
break;
}
default:
break;
}
#if !defined(NDEBUG)
SmallString<32> RelTypeName;
RelI->getTypeName(RelTypeName);
#endif
LLVM_DEBUG(dbgs() << "\t\tIn Section " << SectionID << " Offset " << Offset
<< " RelType: " << RelTypeName << " TargetName: "
<< TargetName << " Addend " << Addend << "\n");
unsigned TargetSectionID = -1;
if (Section == Obj.section_end()) {
RelocationEntry RE(SectionID, Offset, RelType, 0, -1, 0, 0, 0, false, 0);
addRelocationForSymbol(RE, TargetName);
} else {
if (auto TargetSectionIDOrErr =
findOrEmitSection(Obj, *Section, Section->isText(), ObjSectionToID))
TargetSectionID = *TargetSectionIDOrErr;
else
return TargetSectionIDOrErr.takeError();
switch (RelType) {
case COFF::IMAGE_REL_I386_ABSOLUTE:
// This relocation is ignored.
break;
case COFF::IMAGE_REL_I386_DIR32:
case COFF::IMAGE_REL_I386_DIR32NB:
case COFF::IMAGE_REL_I386_REL32: {
RelocationEntry RE =
RelocationEntry(SectionID, Offset, RelType, Addend, TargetSectionID,
getSymbolOffset(*Symbol), 0, 0, false, 0);
addRelocationForSection(RE, TargetSectionID);
break;
}
case COFF::IMAGE_REL_I386_SECTION: {
RelocationEntry RE =
RelocationEntry(TargetSectionID, Offset, RelType, 0);
addRelocationForSection(RE, TargetSectionID);
break;
}
case COFF::IMAGE_REL_I386_SECREL: {
RelocationEntry RE = RelocationEntry(SectionID, Offset, RelType,
getSymbolOffset(*Symbol) + Addend);
addRelocationForSection(RE, TargetSectionID);
break;
}
default:
llvm_unreachable("unsupported relocation type");
}
}
return ++RelI;
}
void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override {
const auto Section = Sections[RE.SectionID];
uint8_t *Target = Section.getAddressWithOffset(RE.Offset);
switch (RE.RelType) {
case COFF::IMAGE_REL_I386_ABSOLUTE:
// This relocation is ignored.
break;
case COFF::IMAGE_REL_I386_DIR32: {
// The target's 32-bit VA.
uint64_t Result =
RE.Sections.SectionA == static_cast<uint32_t>(-1)
? Value
: Sections[RE.Sections.SectionA].getLoadAddressWithOffset(
RE.Addend);
assert(Result <= UINT32_MAX && "relocation overflow");
LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset
<< " RelType: IMAGE_REL_I386_DIR32"
<< " TargetSection: " << RE.Sections.SectionA
<< " Value: " << format("0x%08" PRIx32, Result)
<< '\n');
writeBytesUnaligned(Result, Target, 4);
break;
}
case COFF::IMAGE_REL_I386_DIR32NB: {
// The target's 32-bit RVA.
// NOTE: use Section[0].getLoadAddress() as an approximation of ImageBase
uint64_t Result =
Sections[RE.Sections.SectionA].getLoadAddressWithOffset(RE.Addend) -
Sections[0].getLoadAddress();
assert(Result <= UINT32_MAX && "relocation overflow");
LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset
<< " RelType: IMAGE_REL_I386_DIR32NB"
<< " TargetSection: " << RE.Sections.SectionA
<< " Value: " << format("0x%08" PRIx32, Result)
<< '\n');
writeBytesUnaligned(Result, Target, 4);
break;
}
case COFF::IMAGE_REL_I386_REL32: {
// 32-bit relative displacement to the target.
uint64_t Result = RE.Sections.SectionA == static_cast<uint32_t>(-1)
? Value
: Sections[RE.Sections.SectionA].getLoadAddress();
Result = Result - Section.getLoadAddress() + RE.Addend - 4 - RE.Offset;
assert(static_cast<int64_t>(Result) <= INT32_MAX &&
"relocation overflow");
assert(static_cast<int64_t>(Result) >= INT32_MIN &&
"relocation underflow");
LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset
<< " RelType: IMAGE_REL_I386_REL32"
<< " TargetSection: " << RE.Sections.SectionA
<< " Value: " << format("0x%08" PRIx32, Result)
<< '\n');
writeBytesUnaligned(Result, Target, 4);
break;
}
case COFF::IMAGE_REL_I386_SECTION:
// 16-bit section index of the section that contains the target.
assert(static_cast<uint32_t>(RE.SectionID) <= UINT16_MAX &&
"relocation overflow");
LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset
<< " RelType: IMAGE_REL_I386_SECTION Value: "
<< RE.SectionID << '\n');
writeBytesUnaligned(RE.SectionID, Target, 2);
break;
case COFF::IMAGE_REL_I386_SECREL:
// 32-bit offset of the target from the beginning of its section.
assert(static_cast<uint64_t>(RE.Addend) <= UINT32_MAX &&
"relocation overflow");
LLVM_DEBUG(dbgs() << "\t\tOffset: " << RE.Offset
<< " RelType: IMAGE_REL_I386_SECREL Value: "
<< RE.Addend << '\n');
writeBytesUnaligned(RE.Addend, Target, 4);
break;
default:
llvm_unreachable("unsupported relocation type");
}
}
void registerEHFrames() override {}
};
}
#endif
|
