1 // WebAssemblyFrameLowering.h - TargetFrameLowering for WebAssembly -*- C++ -*-/ 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 /// 10 /// \file 11 /// \brief This class implements WebAssembly-specific bits of 12 /// TargetFrameLowering class. 13 /// 14 //===----------------------------------------------------------------------===// 15 16 #ifndef LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYFRAMELOWERING_H 17 #define LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYFRAMELOWERING_H 18 19 #include "llvm/Target/TargetFrameLowering.h" 20 21 namespace llvm { 22 class MachineFrameInfo; 23 24 class WebAssemblyFrameLowering final : public TargetFrameLowering { 25 public: 26 /// Size of the red zone for the user stack (leaf functions can use this much 27 /// space below the stack pointer without writing it back to memory). 28 // TODO: (ABI) Revisit and decide how large it should be. 29 static const size_t RedZoneSize = 128; 30 WebAssemblyFrameLowering()31 WebAssemblyFrameLowering() 32 : TargetFrameLowering(StackGrowsDown, /*StackAlignment=*/16, 33 /*LocalAreaOffset=*/0, 34 /*TransientStackAlignment=*/16, 35 /*StackRealignable=*/true) {} 36 37 MachineBasicBlock::iterator eliminateCallFramePseudoInstr( 38 MachineFunction &MF, MachineBasicBlock &MBB, 39 MachineBasicBlock::iterator I) const override; 40 41 /// These methods insert prolog and epilog code into the function. 42 void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override; 43 void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override; 44 45 bool hasFP(const MachineFunction &MF) const override; 46 bool hasReservedCallFrame(const MachineFunction &MF) const override; 47 48 private: 49 bool needsSP(const MachineFunction &MF, const MachineFrameInfo &MFI) const; 50 bool needsSPWriteback(const MachineFunction &MF, 51 const MachineFrameInfo &MFI) const; 52 }; 53 54 } // end namespace llvm 55 56 #endif 57