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 17 namespace { 18 class X86MCInstLower; 19 } 20 21 namespace llvm { 22 class MCCodeEmitter; 23 class MCStreamer; 24 class X86Subtarget; 25 class TargetMachine; 26 27 class 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); 123 124 public: 125 X86AsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer); 126 127 StringRef getPassName() const override { 128 return "X86 Assembly Printer"; 129 } 130 131 const X86Subtarget &getSubtarget() const { return *Subtarget; } 132 133 void emitStartOfAsmFile(Module &M) override; 134 135 void emitEndOfAsmFile(Module &M) override; 136 137 void emitInstruction(const MachineInstr *MI) override; 138 139 void emitBasicBlockEnd(const MachineBasicBlock &MBB) override; 140 141 bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo, 142 const char *ExtraCode, raw_ostream &O) override; 143 bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo, 144 const char *ExtraCode, raw_ostream &O) override; 145 146 bool doInitialization(Module &M) override { 147 SMShadowTracker.reset(0); 148 SM.reset(); 149 FM.reset(); 150 return AsmPrinter::doInitialization(M); 151 } 152 153 bool runOnMachineFunction(MachineFunction &MF) override; 154 void emitFunctionBodyStart() override; 155 void emitFunctionBodyEnd() override; 156 void emitKCFITypeId(const MachineFunction &MF) override; 157 158 bool shouldEmitWeakSwiftAsyncExtendedFramePointerFlags() const override { 159 return ShouldEmitWeakSwiftAsyncExtendedFramePointerFlags; 160 } 161 }; 162 163 } // end namespace llvm 164 165 #endif 166