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
|
//===- AArch64TargetStreamer.cpp - AArch64TargetStreamer class ------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements the AArch64TargetStreamer class.
//
//===----------------------------------------------------------------------===//
#include "AArch64TargetStreamer.h"
#include "AArch64MCAsmInfo.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/ConstantPools.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
static cl::opt<bool> MarkBTIProperty(
"aarch64-mark-bti-property", cl::Hidden,
cl::desc("Add .note.gnu.property with BTI to assembly files"),
cl::init(false));
//
// AArch64TargetStreamer Implemenation
//
AArch64TargetStreamer::AArch64TargetStreamer(MCStreamer &S)
: MCTargetStreamer(S), ConstantPools(new AssemblerConstantPools()) {}
AArch64TargetStreamer::~AArch64TargetStreamer() = default;
// The constant pool handling is shared by all AArch64TargetStreamer
// implementations.
const MCExpr *AArch64TargetStreamer::addConstantPoolEntry(const MCExpr *Expr,
unsigned Size,
SMLoc Loc) {
return ConstantPools->addEntry(Streamer, Expr, Size, Loc);
}
void AArch64TargetStreamer::emitCurrentConstantPool() {
ConstantPools->emitForCurrentSection(Streamer);
}
void AArch64TargetStreamer::emitConstantPools() {
ConstantPools->emitAll(Streamer);
}
// finish() - write out any non-empty assembler constant pools and
// write out note.gnu.properties if need.
void AArch64TargetStreamer::finish() {
if (MarkBTIProperty)
emitNoteSection(ELF::GNU_PROPERTY_AARCH64_FEATURE_1_BTI);
}
void AArch64TargetStreamer::emitNoteSection(unsigned Flags,
uint64_t PAuthABIPlatform,
uint64_t PAuthABIVersion) {
assert((PAuthABIPlatform == uint64_t(-1)) ==
(PAuthABIVersion == uint64_t(-1)));
uint64_t DescSz = 0;
if (Flags != 0)
DescSz += 4 * 4;
if (PAuthABIPlatform != uint64_t(-1))
DescSz += 4 + 4 + 8 * 2;
if (DescSz == 0)
return;
MCStreamer &OutStreamer = getStreamer();
MCContext &Context = OutStreamer.getContext();
// Emit a .note.gnu.property section with the flags.
MCSectionELF *Nt = Context.getELFSection(".note.gnu.property", ELF::SHT_NOTE,
ELF::SHF_ALLOC);
if (Nt->isRegistered()) {
SMLoc Loc;
Context.reportWarning(
Loc,
"The .note.gnu.property is not emitted because it is already present.");
return;
}
MCSection *Cur = OutStreamer.getCurrentSectionOnly();
OutStreamer.switchSection(Nt);
// Emit the note header.
OutStreamer.emitValueToAlignment(Align(8));
OutStreamer.emitIntValue(4, 4); // data size for "GNU\0"
OutStreamer.emitIntValue(DescSz, 4); // Elf_Prop array size
OutStreamer.emitIntValue(ELF::NT_GNU_PROPERTY_TYPE_0, 4);
OutStreamer.emitBytes(StringRef("GNU", 4)); // note name
// Emit the PAC/BTI properties.
if (Flags != 0) {
OutStreamer.emitIntValue(ELF::GNU_PROPERTY_AARCH64_FEATURE_1_AND, 4);
OutStreamer.emitIntValue(4, 4); // data size
OutStreamer.emitIntValue(Flags, 4); // data
OutStreamer.emitIntValue(0, 4); // pad
}
// Emit the PAuth ABI compatibility info
if (PAuthABIPlatform != uint64_t(-1)) {
OutStreamer.emitIntValue(ELF::GNU_PROPERTY_AARCH64_FEATURE_PAUTH, 4);
OutStreamer.emitIntValue(8 * 2, 4); // data size
OutStreamer.emitIntValue(PAuthABIPlatform, 8);
OutStreamer.emitIntValue(PAuthABIVersion, 8);
}
OutStreamer.endSection(Nt);
OutStreamer.switchSection(Cur);
}
void AArch64TargetStreamer::emitInst(uint32_t Inst) {
char Buffer[4];
// We can't just use EmitIntValue here, as that will swap the
// endianness on big-endian systems (instructions are always
// little-endian).
for (char &C : Buffer) {
C = uint8_t(Inst);
Inst >>= 8;
}
getStreamer().emitBytes(StringRef(Buffer, 4));
}
MCTargetStreamer *
llvm::createAArch64ObjectTargetStreamer(MCStreamer &S,
const MCSubtargetInfo &STI) {
const Triple &TT = STI.getTargetTriple();
if (TT.isOSBinFormatELF())
return new AArch64TargetELFStreamer(S);
if (TT.isOSBinFormatCOFF())
return new AArch64TargetWinCOFFStreamer(S);
return nullptr;
}
MCTargetStreamer *llvm::createAArch64NullTargetStreamer(MCStreamer &S) {
return new AArch64TargetStreamer(S);
}
|
