1 //===-- WebAssemblyRegisterInfo.cpp - WebAssembly Register Information ----===//
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 //===----------------------------------------------------------------------===//
11 /// \brief This file contains the WebAssembly implementation of the
12 /// TargetRegisterInfo class.
14 //===----------------------------------------------------------------------===//
16 #include "WebAssemblyRegisterInfo.h"
17 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
18 #include "WebAssemblyFrameLowering.h"
19 #include "WebAssemblyInstrInfo.h"
20 #include "WebAssemblyMachineFunctionInfo.h"
21 #include "WebAssemblySubtarget.h"
22 #include "llvm/CodeGen/MachineFrameInfo.h"
23 #include "llvm/CodeGen/MachineInstrBuilder.h"
24 #include "llvm/CodeGen/MachineRegisterInfo.h"
25 #include "llvm/IR/Function.h"
26 #include "llvm/Support/raw_ostream.h"
27 #include "llvm/Target/TargetFrameLowering.h"
28 #include "llvm/Target/TargetOptions.h"
31 #define DEBUG_TYPE "wasm-reg-info"
33 #define GET_REGINFO_TARGET_DESC
34 #include "WebAssemblyGenRegisterInfo.inc"
36 WebAssemblyRegisterInfo::WebAssemblyRegisterInfo(const Triple &TT)
37 : WebAssemblyGenRegisterInfo(0), TT(TT) {}
40 WebAssemblyRegisterInfo::getCalleeSavedRegs(const MachineFunction *) const {
41 static const MCPhysReg CalleeSavedRegs[] = {0};
42 return CalleeSavedRegs;
46 WebAssemblyRegisterInfo::getReservedRegs(const MachineFunction & /*MF*/) const {
47 BitVector Reserved(getNumRegs());
48 for (auto Reg : {WebAssembly::SP32, WebAssembly::SP64, WebAssembly::FP32,
54 void WebAssemblyRegisterInfo::eliminateFrameIndex(
55 MachineBasicBlock::iterator II, int SPAdj,
56 unsigned FIOperandNum, RegScavenger * /*RS*/) const {
58 MachineInstr &MI = *II;
60 MachineBasicBlock &MBB = *MI.getParent();
61 MachineFunction &MF = *MBB.getParent();
62 int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
63 const MachineFrameInfo& MFI = *MF.getFrameInfo();
64 int64_t FrameOffset = MFI.getStackSize() + MFI.getObjectOffset(FrameIndex);
66 if (MI.mayLoadOrStore()) {
67 // If this is a load or store, make it relative to SP and fold the frame
68 // offset directly in.
69 assert(FrameOffset >= 0 && MI.getOperand(1).getImm() >= 0);
70 int64_t Offset = MI.getOperand(1).getImm() + FrameOffset;
72 if (static_cast<uint64_t>(Offset) > std::numeric_limits<uint32_t>::max()) {
73 // If this happens the program is invalid, but better to error here than
74 // generate broken code.
75 report_fatal_error("Memory offset field overflow");
77 MI.getOperand(1).setImm(Offset);
78 MI.getOperand(2).ChangeToRegister(WebAssembly::SP32, /*IsDef=*/false);
80 // Otherwise create an i32.add SP, offset and make it the operand.
81 auto &MRI = MF.getRegInfo();
82 const auto *TII = MF.getSubtarget().getInstrInfo();
84 unsigned OffsetReg = MRI.createVirtualRegister(&WebAssembly::I32RegClass);
85 BuildMI(MBB, MI, MI.getDebugLoc(), TII->get(WebAssembly::CONST_I32), OffsetReg)
87 BuildMI(MBB, MI, MI.getDebugLoc(), TII->get(WebAssembly::ADD_I32), OffsetReg)
88 .addReg(WebAssembly::SP32)
90 MI.getOperand(FIOperandNum).ChangeToRegister(OffsetReg, /*IsDef=*/false);
95 WebAssemblyRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
96 static const unsigned Regs[2][2] = {
97 /* !isArch64Bit isArch64Bit */
98 /* !hasFP */ {WebAssembly::SP32, WebAssembly::SP64},
99 /* hasFP */ {WebAssembly::FP32, WebAssembly::FP64}};
100 const WebAssemblyFrameLowering *TFI = getFrameLowering(MF);
101 return Regs[TFI->hasFP(MF)][TT.isArch64Bit()];
104 const TargetRegisterClass *
105 WebAssemblyRegisterInfo::getPointerRegClass(const MachineFunction &MF,
106 unsigned Kind) const {
107 assert(Kind == 0 && "Only one kind of pointer on WebAssembly");
108 if (MF.getSubtarget<WebAssemblySubtarget>().hasAddr64())
109 return &WebAssembly::I64RegClass;
110 return &WebAssembly::I32RegClass;