1 //===-- WebAssemblyAsmPrinter.cpp - WebAssembly LLVM assembly writer ------===//
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 a printer that converts from our internal
12 /// representation of machine-dependent LLVM code to the WebAssembly assembly
15 //===----------------------------------------------------------------------===//
17 #include "WebAssembly.h"
18 #include "InstPrinter/WebAssemblyInstPrinter.h"
19 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
20 #include "WebAssemblyMCInstLower.h"
21 #include "WebAssemblyMachineFunctionInfo.h"
22 #include "WebAssemblyRegisterInfo.h"
23 #include "WebAssemblySubtarget.h"
24 #include "llvm/ADT/StringExtras.h"
25 #include "llvm/CodeGen/Analysis.h"
26 #include "llvm/CodeGen/AsmPrinter.h"
27 #include "llvm/CodeGen/MachineConstantPool.h"
28 #include "llvm/CodeGen/MachineInstr.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/MC/MCContext.h"
31 #include "llvm/MC/MCStreamer.h"
32 #include "llvm/MC/MCSymbol.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/TargetRegistry.h"
35 #include "llvm/Support/raw_ostream.h"
38 #define DEBUG_TYPE "asm-printer"
42 class WebAssemblyAsmPrinter final : public AsmPrinter {
43 const MachineRegisterInfo *MRI;
44 const WebAssemblyFunctionInfo *MFI;
47 WebAssemblyAsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
48 : AsmPrinter(TM, std::move(Streamer)), MRI(nullptr), MFI(nullptr) {}
51 const char *getPassName() const override {
52 return "WebAssembly Assembly Printer";
55 //===------------------------------------------------------------------===//
56 // MachineFunctionPass Implementation.
57 //===------------------------------------------------------------------===//
59 bool runOnMachineFunction(MachineFunction &MF) override {
60 MRI = &MF.getRegInfo();
61 MFI = MF.getInfo<WebAssemblyFunctionInfo>();
62 return AsmPrinter::runOnMachineFunction(MF);
65 //===------------------------------------------------------------------===//
66 // AsmPrinter Implementation.
67 //===------------------------------------------------------------------===//
69 void EmitJumpTableInfo() override;
70 void EmitConstantPool() override;
71 void EmitFunctionBodyStart() override;
72 void EmitInstruction(const MachineInstr *MI) override;
73 bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
74 unsigned AsmVariant, const char *ExtraCode,
75 raw_ostream &OS) override;
76 bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
77 unsigned AsmVariant, const char *ExtraCode,
78 raw_ostream &OS) override;
80 MVT getRegType(unsigned RegNo) const;
81 const char *toString(MVT VT) const;
82 std::string regToString(const MachineOperand &MO);
85 } // end anonymous namespace
87 //===----------------------------------------------------------------------===//
89 //===----------------------------------------------------------------------===//
91 MVT WebAssemblyAsmPrinter::getRegType(unsigned RegNo) const {
92 const TargetRegisterClass *TRC =
93 TargetRegisterInfo::isVirtualRegister(RegNo) ?
94 MRI->getRegClass(RegNo) :
95 MRI->getTargetRegisterInfo()->getMinimalPhysRegClass(RegNo);
96 for (MVT T : {MVT::i32, MVT::i64, MVT::f32, MVT::f64})
99 DEBUG(errs() << "Unknown type for register number: " << RegNo);
100 llvm_unreachable("Unknown register type");
104 std::string WebAssemblyAsmPrinter::regToString(const MachineOperand &MO) {
105 unsigned RegNo = MO.getReg();
106 assert(TargetRegisterInfo::isVirtualRegister(RegNo) &&
107 "Unlowered physical register encountered during assembly printing");
108 assert(!MFI->isVRegStackified(RegNo));
109 unsigned WAReg = MFI->getWAReg(RegNo);
110 assert(WAReg != WebAssemblyFunctionInfo::UnusedReg);
111 return '$' + utostr(WAReg);
114 const char *WebAssemblyAsmPrinter::toString(MVT VT) const {
115 return WebAssembly::TypeToString(VT);
118 //===----------------------------------------------------------------------===//
119 // WebAssemblyAsmPrinter Implementation.
120 //===----------------------------------------------------------------------===//
122 void WebAssemblyAsmPrinter::EmitConstantPool() {
123 assert(MF->getConstantPool()->getConstants().empty() &&
124 "WebAssembly disables constant pools");
127 void WebAssemblyAsmPrinter::EmitJumpTableInfo() {
128 // Nothing to do; jump tables are incorporated into the instruction stream.
131 static void ComputeLegalValueVTs(const Function &F, const TargetMachine &TM,
132 Type *Ty, SmallVectorImpl<MVT> &ValueVTs) {
133 const DataLayout &DL(F.getParent()->getDataLayout());
134 const WebAssemblyTargetLowering &TLI =
135 *TM.getSubtarget<WebAssemblySubtarget>(F).getTargetLowering();
136 SmallVector<EVT, 4> VTs;
137 ComputeValueVTs(TLI, DL, Ty, VTs);
140 unsigned NumRegs = TLI.getNumRegisters(F.getContext(), VT);
141 MVT RegisterVT = TLI.getRegisterType(F.getContext(), VT);
142 for (unsigned i = 0; i != NumRegs; ++i)
143 ValueVTs.push_back(RegisterVT);
147 void WebAssemblyAsmPrinter::EmitFunctionBodyStart() {
148 if (!MFI->getParams().empty()) {
150 Param.setOpcode(WebAssembly::PARAM);
151 for (MVT VT : MFI->getParams())
152 Param.addOperand(MCOperand::createImm(VT.SimpleTy));
153 EmitToStreamer(*OutStreamer, Param);
156 SmallVector<MVT, 4> ResultVTs;
157 const Function &F(*MF->getFunction());
158 ComputeLegalValueVTs(F, TM, F.getReturnType(), ResultVTs);
159 // If the return type needs to be legalized it will get converted into
160 // passing a pointer.
161 if (ResultVTs.size() == 1) {
163 Result.setOpcode(WebAssembly::RESULT);
164 Result.addOperand(MCOperand::createImm(ResultVTs.front().SimpleTy));
165 EmitToStreamer(*OutStreamer, Result);
168 bool AnyWARegs = false;
170 Local.setOpcode(WebAssembly::LOCAL);
171 for (unsigned Idx = 0, IdxE = MRI->getNumVirtRegs(); Idx != IdxE; ++Idx) {
172 unsigned VReg = TargetRegisterInfo::index2VirtReg(Idx);
173 unsigned WAReg = MFI->getWAReg(VReg);
174 // Don't declare unused registers.
175 if (WAReg == WebAssemblyFunctionInfo::UnusedReg)
177 // Don't redeclare parameters.
178 if (WAReg < MFI->getParams().size())
180 // Don't declare stackified registers.
183 Local.addOperand(MCOperand::createImm(getRegType(VReg).SimpleTy));
186 auto &PhysRegs = MFI->getPhysRegs();
187 for (unsigned PReg = 0; PReg < PhysRegs.size(); ++PReg) {
188 if (PhysRegs[PReg] == -1U)
190 Local.addOperand(MCOperand::createImm(getRegType(PReg).SimpleTy));
194 EmitToStreamer(*OutStreamer, Local);
196 AsmPrinter::EmitFunctionBodyStart();
199 void WebAssemblyAsmPrinter::EmitInstruction(const MachineInstr *MI) {
200 DEBUG(dbgs() << "EmitInstruction: " << *MI << '\n');
202 switch (MI->getOpcode()) {
203 case WebAssembly::ARGUMENT_I32:
204 case WebAssembly::ARGUMENT_I64:
205 case WebAssembly::ARGUMENT_F32:
206 case WebAssembly::ARGUMENT_F64:
207 // These represent values which are live into the function entry, so there's
208 // no instruction to emit.
210 case WebAssembly::LOOP_END:
211 // This is a no-op which just exists to tell AsmPrinter.cpp that there's a
212 // fallthrough which nevertheless requires a label for the destination here.
215 WebAssemblyMCInstLower MCInstLowering(OutContext, *this);
217 MCInstLowering.Lower(MI, TmpInst);
218 EmitToStreamer(*OutStreamer, TmpInst);
224 bool WebAssemblyAsmPrinter::PrintAsmOperand(const MachineInstr *MI,
225 unsigned OpNo, unsigned AsmVariant,
226 const char *ExtraCode,
229 report_fatal_error("There are no defined alternate asm variants");
231 // First try the generic code, which knows about modifiers like 'c' and 'n'.
232 if (!AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, OS))
236 const MachineOperand &MO = MI->getOperand(OpNo);
237 switch (MO.getType()) {
238 case MachineOperand::MO_Immediate:
241 case MachineOperand::MO_Register:
242 OS << regToString(MO);
244 case MachineOperand::MO_GlobalAddress:
245 getSymbol(MO.getGlobal())->print(OS, MAI);
246 printOffset(MO.getOffset(), OS);
248 case MachineOperand::MO_ExternalSymbol:
249 GetExternalSymbolSymbol(MO.getSymbolName())->print(OS, MAI);
250 printOffset(MO.getOffset(), OS);
252 case MachineOperand::MO_MachineBasicBlock:
253 MO.getMBB()->getSymbol()->print(OS, MAI);
263 bool WebAssemblyAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
266 const char *ExtraCode,
269 report_fatal_error("There are no defined alternate asm variants");
272 // TODO: For now, we just hard-code 0 as the constant offset; teach
273 // SelectInlineAsmMemoryOperand how to do address mode matching.
274 OS << "0(" + regToString(MI->getOperand(OpNo)) + ')';
278 return AsmPrinter::PrintAsmMemoryOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
281 // Force static initialization.
282 extern "C" void LLVMInitializeWebAssemblyAsmPrinter() {
283 RegisterAsmPrinter<WebAssemblyAsmPrinter> X(TheWebAssemblyTarget32);
284 RegisterAsmPrinter<WebAssemblyAsmPrinter> Y(TheWebAssemblyTarget64);