1 //===-- X86AsmPrinter.h - X86 implementation of AsmPrinter ------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef LLVM_LIB_TARGET_X86_X86ASMPRINTER_H
11 #define LLVM_LIB_TARGET_X86_X86ASMPRINTER_H
13 #include "X86Subtarget.h"
14 #include "llvm/CodeGen/AsmPrinter.h"
15 #include "llvm/CodeGen/FaultMaps.h"
16 #include "llvm/CodeGen/StackMaps.h"
17 #include "llvm/Target/TargetMachine.h"
19 // Implemented in X86MCInstLower.cpp
28 class LLVM_LIBRARY_VISIBILITY X86AsmPrinter : public AsmPrinter {
29 const X86Subtarget *Subtarget;
32 std::unique_ptr<MCCodeEmitter> CodeEmitter;
34 // This utility class tracks the length of a stackmap instruction's 'shadow'.
35 // It is used by the X86AsmPrinter to ensure that the stackmap shadow
36 // invariants (i.e. no other stackmaps, patchpoints, or control flow within
37 // the shadow) are met, while outputting a minimal number of NOPs for padding.
39 // To minimise the number of NOPs used, the shadow tracker counts the number
40 // of instruction bytes output since the last stackmap. Only if there are too
41 // few instruction bytes to cover the shadow are NOPs used for padding.
42 class StackMapShadowTracker {
44 void startFunction(MachineFunction &MF) {
47 void count(MCInst &Inst, const MCSubtargetInfo &STI,
48 MCCodeEmitter *CodeEmitter);
50 // Called to signal the start of a shadow of RequiredSize bytes.
51 void reset(unsigned RequiredSize) {
52 RequiredShadowSize = RequiredSize;
53 CurrentShadowSize = 0;
57 // Called before every stackmap/patchpoint, and at the end of basic blocks,
58 // to emit any necessary padding-NOPs.
59 void emitShadowPadding(MCStreamer &OutStreamer, const MCSubtargetInfo &STI);
61 const MachineFunction *MF;
62 bool InShadow = false;
64 // RequiredShadowSize holds the length of the shadow specified in the most
65 // recently encountered STACKMAP instruction.
66 // CurrentShadowSize counts the number of bytes encoded since the most
67 // recently encountered STACKMAP, stopping when that number is greater than
68 // or equal to RequiredShadowSize.
69 unsigned RequiredShadowSize = 0, CurrentShadowSize = 0;
72 StackMapShadowTracker SMShadowTracker;
74 // All instructions emitted by the X86AsmPrinter should use this helper
77 // This helper function invokes the SMShadowTracker on each instruction before
78 // outputting it to the OutStream. This allows the shadow tracker to minimise
79 // the number of NOPs used for stackmap padding.
80 void EmitAndCountInstruction(MCInst &Inst);
81 void LowerSTACKMAP(const MachineInstr &MI);
82 void LowerPATCHPOINT(const MachineInstr &MI, X86MCInstLower &MCIL);
83 void LowerSTATEPOINT(const MachineInstr &MI, X86MCInstLower &MCIL);
84 void LowerFAULTING_LOAD_OP(const MachineInstr &MI, X86MCInstLower &MCIL);
85 void LowerPATCHABLE_OP(const MachineInstr &MI, X86MCInstLower &MCIL);
87 void LowerTlsAddr(X86MCInstLower &MCInstLowering, const MachineInstr &MI);
89 // XRay-specific lowering for X86.
90 void LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI,
91 X86MCInstLower &MCIL);
92 void LowerPATCHABLE_RET(const MachineInstr &MI, X86MCInstLower &MCIL);
93 void LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI, X86MCInstLower &MCIL);
95 // Helper function that emits the XRay sleds we've collected for a particular
100 explicit X86AsmPrinter(TargetMachine &TM,
101 std::unique_ptr<MCStreamer> Streamer)
102 : AsmPrinter(TM, std::move(Streamer)), SM(*this), FM(*this) {}
104 StringRef getPassName() const override {
105 return "X86 Assembly Printer";
108 const X86Subtarget &getSubtarget() const { return *Subtarget; }
110 void EmitStartOfAsmFile(Module &M) override;
112 void EmitEndOfAsmFile(Module &M) override;
114 void EmitInstruction(const MachineInstr *MI) override;
116 void EmitBasicBlockEnd(const MachineBasicBlock &MBB) override {
117 SMShadowTracker.emitShadowPadding(*OutStreamer, getSubtargetInfo());
120 bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
121 unsigned AsmVariant, const char *ExtraCode,
122 raw_ostream &OS) override;
123 bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
124 unsigned AsmVariant, const char *ExtraCode,
125 raw_ostream &OS) override;
127 /// \brief Return the symbol for the specified constant pool entry.
128 MCSymbol *GetCPISymbol(unsigned CPID) const override;
130 bool doInitialization(Module &M) override {
131 SMShadowTracker.reset(0);
133 return AsmPrinter::doInitialization(M);
136 bool runOnMachineFunction(MachineFunction &F) override;
139 } // end namespace llvm