1//===-- X86AsmPrinter.h - X86 implementation of AsmPrinter ------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_LIB_TARGET_X86_X86ASMPRINTER_H
10#define LLVM_LIB_TARGET_X86_X86ASMPRINTER_H
11
12#include "llvm/CodeGen/AsmPrinter.h"
13#include "llvm/CodeGen/FaultMaps.h"
14#include "llvm/CodeGen/StackMaps.h"
15
16// Implemented in X86MCInstLower.cpp
17namespace {
18 class X86MCInstLower;
19}
20
21namespace llvm {
22class MCCodeEmitter;
23class MCStreamer;
24class X86Subtarget;
25class TargetMachine;
26
27class LLVM_LIBRARY_VISIBILITY X86AsmPrinter : public AsmPrinter {
28 const X86Subtarget *Subtarget = nullptr;
29 FaultMaps FM;
30 std::unique_ptr<MCCodeEmitter> CodeEmitter;
31 bool EmitFPOData = false;
32 bool ShouldEmitWeakSwiftAsyncExtendedFramePointerFlags = false;
33 bool IndCSPrefix = false;
34
35 // This utility class tracks the length of a stackmap instruction's 'shadow'.
36 // It is used by the X86AsmPrinter to ensure that the stackmap shadow
37 // invariants (i.e. no other stackmaps, patchpoints, or control flow within
38 // the shadow) are met, while outputting a minimal number of NOPs for padding.
39 //
40 // To minimise the number of NOPs used, the shadow tracker counts the number
41 // of instruction bytes output since the last stackmap. Only if there are too
42 // few instruction bytes to cover the shadow are NOPs used for padding.
43 class StackMapShadowTracker {
44 public:
45 void startFunction(MachineFunction &MF) {
46 this->MF = &MF;
47 }
48 void count(MCInst &Inst, const MCSubtargetInfo &STI,
49 MCCodeEmitter *CodeEmitter);
50
51 // Called to signal the start of a shadow of RequiredSize bytes.
52 void reset(unsigned RequiredSize) {
53 RequiredShadowSize = RequiredSize;
54 CurrentShadowSize = 0;
55 InShadow = true;
56 }
57
58 // Called before every stackmap/patchpoint, and at the end of basic blocks,
59 // to emit any necessary padding-NOPs.
60 void emitShadowPadding(MCStreamer &OutStreamer, const MCSubtargetInfo &STI);
61 private:
62 const MachineFunction *MF = nullptr;
63 bool InShadow = false;
64
65 // RequiredShadowSize holds the length of the shadow specified in the most
66 // recently encountered STACKMAP instruction.
67 // CurrentShadowSize counts the number of bytes encoded since the most
68 // recently encountered STACKMAP, stopping when that number is greater than
69 // or equal to RequiredShadowSize.
70 unsigned RequiredShadowSize = 0, CurrentShadowSize = 0;
71 };
72
73 StackMapShadowTracker SMShadowTracker;
74
75 // All instructions emitted by the X86AsmPrinter should use this helper
76 // method.
77 //
78 // This helper function invokes the SMShadowTracker on each instruction before
79 // outputting it to the OutStream. This allows the shadow tracker to minimise
80 // the number of NOPs used for stackmap padding.
81 void EmitAndCountInstruction(MCInst &Inst);
82 void LowerSTACKMAP(const MachineInstr &MI);
83 void LowerPATCHPOINT(const MachineInstr &MI, X86MCInstLower &MCIL);
84 void LowerSTATEPOINT(const MachineInstr &MI, X86MCInstLower &MCIL);
85 void LowerFAULTING_OP(const MachineInstr &MI, X86MCInstLower &MCIL);
86 void LowerPATCHABLE_OP(const MachineInstr &MI, X86MCInstLower &MCIL);
87
88 void LowerTlsAddr(X86MCInstLower &MCInstLowering, const MachineInstr &MI);
89
90 // XRay-specific lowering for X86.
91 void LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI,
92 X86MCInstLower &MCIL);
93 void LowerPATCHABLE_RET(const MachineInstr &MI, X86MCInstLower &MCIL);
94 void LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI, X86MCInstLower &MCIL);
95 void LowerPATCHABLE_EVENT_CALL(const MachineInstr &MI, X86MCInstLower &MCIL);
96 void LowerPATCHABLE_TYPED_EVENT_CALL(const MachineInstr &MI,
97 X86MCInstLower &MCIL);
98
99 void LowerFENTRY_CALL(const MachineInstr &MI, X86MCInstLower &MCIL);
100
101 // KCFI specific lowering for X86.
102 uint32_t MaskKCFIType(uint32_t Value);
103 void EmitKCFITypePadding(const MachineFunction &MF, bool HasType = true);
104 void LowerKCFI_CHECK(const MachineInstr &MI);
105
106 // Address sanitizer specific lowering for X86.
107 void LowerASAN_CHECK_MEMACCESS(const MachineInstr &MI);
108
109 // Choose between emitting .seh_ directives and .cv_fpo_ directives.
110 void EmitSEHInstruction(const MachineInstr *MI);
111
112 void PrintSymbolOperand(const MachineOperand &MO, raw_ostream &O) override;
113 void PrintOperand(const MachineInstr *MI, unsigned OpNo, raw_ostream &O);
114 void PrintModifiedOperand(const MachineInstr *MI, unsigned OpNo,
115 raw_ostream &O, const char *Modifier);
116 void PrintPCRelImm(const MachineInstr *MI, unsigned OpNo, raw_ostream &O);
117 void PrintLeaMemReference(const MachineInstr *MI, unsigned OpNo,
118 raw_ostream &O, const char *Modifier);
119 void PrintMemReference(const MachineInstr *MI, unsigned OpNo, raw_ostream &O,
120 const char *Modifier);
121 void PrintIntelMemReference(const MachineInstr *MI, unsigned OpNo,
122 raw_ostream &O, const char *Modifier);
123 const MCSubtargetInfo *getIFuncMCSubtargetInfo() const override;
124 void emitMachOIFuncStubBody(Module &M, const GlobalIFunc &GI,
125 MCSymbol *LazyPointer) override;
126 void emitMachOIFuncStubHelperBody(Module &M, const GlobalIFunc &GI,
127 MCSymbol *LazyPointer) override;
128
129public:
130 X86AsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer);
131
132 StringRef getPassName() const override {
133 return "X86 Assembly Printer";
134 }
135
136 const X86Subtarget &getSubtarget() const { return *Subtarget; }
137
138 void emitStartOfAsmFile(Module &M) override;
139
140 void emitEndOfAsmFile(Module &M) override;
141
142 void emitInstruction(const MachineInstr *MI) override;
143
144 void emitBasicBlockEnd(const MachineBasicBlock &MBB) override;
145
146 bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
147 const char *ExtraCode, raw_ostream &O) override;
148 bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
149 const char *ExtraCode, raw_ostream &O) override;
150
151 bool doInitialization(Module &M) override {
152 SMShadowTracker.reset(RequiredSize: 0);
153 SM.reset();
154 FM.reset();
155 return AsmPrinter::doInitialization(M);
156 }
157
158 bool runOnMachineFunction(MachineFunction &MF) override;
159 void emitFunctionBodyStart() override;
160 void emitFunctionBodyEnd() override;
161 void emitKCFITypeId(const MachineFunction &MF) override;
162
163 bool shouldEmitWeakSwiftAsyncExtendedFramePointerFlags() const override {
164 return ShouldEmitWeakSwiftAsyncExtendedFramePointerFlags;
165 }
166};
167
168} // end namespace llvm
169
170#endif
171