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
|
//===-- X86AsmPrinter.h - X86 implementation of AsmPrinter ------*- 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_X86_X86ASMPRINTER_H
#define LLVM_LIB_TARGET_X86_X86ASMPRINTER_H
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/FaultMaps.h"
#include "llvm/CodeGen/StackMaps.h"
// Implemented in X86MCInstLower.cpp
namespace {
class X86MCInstLower;
}
namespace llvm {
class MCCodeEmitter;
class MCStreamer;
class X86Subtarget;
class TargetMachine;
class LLVM_LIBRARY_VISIBILITY X86AsmPrinter : public AsmPrinter {
const X86Subtarget *Subtarget = nullptr;
StackMaps SM;
FaultMaps FM;
std::unique_ptr<MCCodeEmitter> CodeEmitter;
bool EmitFPOData = false;
bool NeedsRetpoline = false;
// This utility class tracks the length of a stackmap instruction's 'shadow'.
// It is used by the X86AsmPrinter to ensure that the stackmap shadow
// invariants (i.e. no other stackmaps, patchpoints, or control flow within
// the shadow) are met, while outputting a minimal number of NOPs for padding.
//
// To minimise the number of NOPs used, the shadow tracker counts the number
// of instruction bytes output since the last stackmap. Only if there are too
// few instruction bytes to cover the shadow are NOPs used for padding.
class StackMapShadowTracker {
public:
void startFunction(MachineFunction &MF) {
this->MF = &MF;
}
void count(MCInst &Inst, const MCSubtargetInfo &STI,
MCCodeEmitter *CodeEmitter);
// Called to signal the start of a shadow of RequiredSize bytes.
void reset(unsigned RequiredSize) {
RequiredShadowSize = RequiredSize;
CurrentShadowSize = 0;
InShadow = true;
}
// Called before every stackmap/patchpoint, and at the end of basic blocks,
// to emit any necessary padding-NOPs.
void emitShadowPadding(MCStreamer &OutStreamer, const MCSubtargetInfo &STI);
private:
const MachineFunction *MF = nullptr;
bool InShadow = false;
// RequiredShadowSize holds the length of the shadow specified in the most
// recently encountered STACKMAP instruction.
// CurrentShadowSize counts the number of bytes encoded since the most
// recently encountered STACKMAP, stopping when that number is greater than
// or equal to RequiredShadowSize.
unsigned RequiredShadowSize = 0, CurrentShadowSize = 0;
};
StackMapShadowTracker SMShadowTracker;
// All instructions emitted by the X86AsmPrinter should use this helper
// method.
//
// This helper function invokes the SMShadowTracker on each instruction before
// outputting it to the OutStream. This allows the shadow tracker to minimise
// the number of NOPs used for stackmap padding.
void EmitAndCountInstruction(MCInst &Inst);
void LowerSTACKMAP(const MachineInstr &MI);
void LowerPATCHPOINT(const MachineInstr &MI, X86MCInstLower &MCIL);
void LowerSTATEPOINT(const MachineInstr &MI, X86MCInstLower &MCIL);
void LowerFAULTING_OP(const MachineInstr &MI, X86MCInstLower &MCIL);
void LowerPATCHABLE_OP(const MachineInstr &MI, X86MCInstLower &MCIL);
void LowerTlsAddr(X86MCInstLower &MCInstLowering, const MachineInstr &MI);
// XRay-specific lowering for X86.
void LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI,
X86MCInstLower &MCIL);
void LowerPATCHABLE_RET(const MachineInstr &MI, X86MCInstLower &MCIL);
void LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI, X86MCInstLower &MCIL);
void LowerPATCHABLE_EVENT_CALL(const MachineInstr &MI, X86MCInstLower &MCIL);
void LowerPATCHABLE_TYPED_EVENT_CALL(const MachineInstr &MI,
X86MCInstLower &MCIL);
void LowerFENTRY_CALL(const MachineInstr &MI, X86MCInstLower &MCIL);
// Choose between emitting .seh_ directives and .cv_fpo_ directives.
void EmitSEHInstruction(const MachineInstr *MI);
void PrintSymbolOperand(const MachineOperand &MO, raw_ostream &O) override;
void PrintOperand(const MachineInstr *MI, unsigned OpNo, raw_ostream &O);
void PrintModifiedOperand(const MachineInstr *MI, unsigned OpNo,
raw_ostream &O, const char *Modifier);
void PrintPCRelImm(const MachineInstr *MI, unsigned OpNo, raw_ostream &O);
void PrintLeaMemReference(const MachineInstr *MI, unsigned OpNo,
raw_ostream &O, const char *Modifier);
void PrintMemReference(const MachineInstr *MI, unsigned OpNo, raw_ostream &O,
const char *Modifier);
void PrintIntelMemReference(const MachineInstr *MI, unsigned OpNo,
raw_ostream &O, const char *Modifier);
public:
X86AsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer);
StringRef getPassName() const override {
return "X86 Assembly Printer";
}
const X86Subtarget &getSubtarget() const { return *Subtarget; }
void emitStartOfAsmFile(Module &M) override;
void emitEndOfAsmFile(Module &M) override;
void emitInstruction(const MachineInstr *MI) override;
void emitBasicBlockEnd(const MachineBasicBlock &MBB) override {
AsmPrinter::emitBasicBlockEnd(MBB);
SMShadowTracker.emitShadowPadding(*OutStreamer, getSubtargetInfo());
}
bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
const char *ExtraCode, raw_ostream &O) override;
bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
const char *ExtraCode, raw_ostream &O) override;
bool doInitialization(Module &M) override {
SMShadowTracker.reset(0);
SM.reset();
FM.reset();
return AsmPrinter::doInitialization(M);
}
bool runOnMachineFunction(MachineFunction &MF) override;
void emitFunctionBodyStart() override;
void emitFunctionBodyEnd() override;
};
} // end namespace llvm
#endif
|
