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/SmallString.h"
25 #include "llvm/ADT/StringExtras.h"
26 #include "llvm/CodeGen/Analysis.h"
27 #include "llvm/CodeGen/AsmPrinter.h"
28 #include "llvm/CodeGen/MachineConstantPool.h"
29 #include "llvm/CodeGen/MachineInstr.h"
30 #include "llvm/IR/DataLayout.h"
31 #include "llvm/MC/MCContext.h"
32 #include "llvm/MC/MCStreamer.h"
33 #include "llvm/MC/MCSymbol.h"
34 #include "llvm/Support/Debug.h"
35 #include "llvm/Support/TargetRegistry.h"
36 #include "llvm/Support/raw_ostream.h"
40 #define DEBUG_TYPE "asm-printer"
44 class WebAssemblyAsmPrinter final : public AsmPrinter {
45 const MachineRegisterInfo *MRI;
46 const WebAssemblyFunctionInfo *MFI;
49 WebAssemblyAsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
50 : AsmPrinter(TM, std::move(Streamer)), MRI(nullptr), MFI(nullptr) {}
53 const char *getPassName() const override {
54 return "WebAssembly Assembly Printer";
57 //===------------------------------------------------------------------===//
58 // MachineFunctionPass Implementation.
59 //===------------------------------------------------------------------===//
61 void getAnalysisUsage(AnalysisUsage &AU) const override {
62 AsmPrinter::getAnalysisUsage(AU);
65 bool runOnMachineFunction(MachineFunction &MF) override {
66 MRI = &MF.getRegInfo();
67 MFI = MF.getInfo<WebAssemblyFunctionInfo>();
68 return AsmPrinter::runOnMachineFunction(MF);
71 //===------------------------------------------------------------------===//
72 // AsmPrinter Implementation.
73 //===------------------------------------------------------------------===//
75 void EmitJumpTableInfo() override;
76 void EmitConstantPool() override;
77 void EmitFunctionBodyStart() override;
78 void EmitInstruction(const MachineInstr *MI) override;
79 void EmitEndOfAsmFile(Module &M) override;
80 bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
81 unsigned AsmVariant, const char *ExtraCode,
82 raw_ostream &OS) override;
83 bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
84 unsigned AsmVariant, const char *ExtraCode,
85 raw_ostream &OS) override;
87 MVT getRegType(unsigned RegNo) const;
88 const char *toString(MVT VT) const;
89 std::string regToString(const MachineOperand &MO);
92 } // end anonymous namespace
94 //===----------------------------------------------------------------------===//
96 //===----------------------------------------------------------------------===//
98 MVT WebAssemblyAsmPrinter::getRegType(unsigned RegNo) const {
99 const TargetRegisterClass *TRC = MRI->getRegClass(RegNo);
100 for (MVT T : {MVT::i32, MVT::i64, MVT::f32, MVT::f64})
103 DEBUG(errs() << "Unknown type for register number: " << RegNo);
104 llvm_unreachable("Unknown register type");
108 std::string WebAssemblyAsmPrinter::regToString(const MachineOperand &MO) {
109 unsigned RegNo = MO.getReg();
110 assert(TargetRegisterInfo::isVirtualRegister(RegNo) &&
111 "Unlowered physical register encountered during assembly printing");
112 assert(!MFI->isVRegStackified(RegNo));
113 unsigned WAReg = MFI->getWAReg(RegNo);
114 assert(WAReg != WebAssemblyFunctionInfo::UnusedReg);
115 return '$' + utostr(WAReg);
118 const char *WebAssemblyAsmPrinter::toString(MVT VT) const {
119 switch (VT.SimpleTy) {
131 DEBUG(dbgs() << "Invalid type " << EVT(VT).getEVTString() << '\n');
132 llvm_unreachable("invalid type");
136 //===----------------------------------------------------------------------===//
137 // WebAssemblyAsmPrinter Implementation.
138 //===----------------------------------------------------------------------===//
140 void WebAssemblyAsmPrinter::EmitConstantPool() {
141 assert(MF->getConstantPool()->getConstants().empty() &&
142 "WebAssembly disables constant pools");
145 void WebAssemblyAsmPrinter::EmitJumpTableInfo() {
146 // Nothing to do; jump tables are incorporated into the instruction stream.
149 static void ComputeLegalValueVTs(const Function &F,
150 const TargetMachine &TM,
152 SmallVectorImpl<MVT> &ValueVTs) {
153 const DataLayout& DL(F.getParent()->getDataLayout());
154 const WebAssemblyTargetLowering &TLI =
155 *TM.getSubtarget<WebAssemblySubtarget>(F).getTargetLowering();
156 SmallVector<EVT, 4> VTs;
157 ComputeValueVTs(TLI, DL, Ty, VTs);
160 unsigned NumRegs = TLI.getNumRegisters(F.getContext(), VT);
161 MVT RegisterVT = TLI.getRegisterType(F.getContext(), VT);
162 for (unsigned i = 0; i != NumRegs; ++i)
163 ValueVTs.push_back(RegisterVT);
167 void WebAssemblyAsmPrinter::EmitFunctionBodyStart() {
168 if (!MFI->getParams().empty()) {
170 Param.setOpcode(WebAssembly::PARAM);
171 for (MVT VT : MFI->getParams())
172 Param.addOperand(MCOperand::createImm(VT.SimpleTy));
173 EmitToStreamer(*OutStreamer, Param);
177 SmallVector<MVT, 4> ResultVTs;
178 const Function &F(*MF->getFunction());
179 ComputeLegalValueVTs(F, TM, F.getReturnType(), ResultVTs);
180 // If the return type needs to be legalized it will get converted into
181 // passing a pointer.
182 if (ResultVTs.size() == 1) {
184 Result.setOpcode(WebAssembly::RESULT);
185 Result.addOperand(MCOperand::createImm(ResultVTs.front().SimpleTy));
186 EmitToStreamer(*OutStreamer, Result);
189 bool AnyWARegs = false;
191 Local.setOpcode(WebAssembly::LOCAL);
192 for (unsigned Idx = 0, IdxE = MRI->getNumVirtRegs(); Idx != IdxE; ++Idx) {
193 unsigned VReg = TargetRegisterInfo::index2VirtReg(Idx);
194 unsigned WAReg = MFI->getWAReg(VReg);
195 // Don't declare unused registers.
196 if (WAReg == WebAssemblyFunctionInfo::UnusedReg)
198 // Don't redeclare parameters.
199 if (WAReg < MFI->getParams().size())
201 // Don't declare stackified registers.
204 Local.addOperand(MCOperand::createImm(getRegType(VReg).SimpleTy));
208 EmitToStreamer(*OutStreamer, Local);
210 AsmPrinter::EmitFunctionBodyStart();
213 void WebAssemblyAsmPrinter::EmitInstruction(const MachineInstr *MI) {
214 DEBUG(dbgs() << "EmitInstruction: " << *MI << '\n');
216 switch (MI->getOpcode()) {
217 case WebAssembly::ARGUMENT_I32:
218 case WebAssembly::ARGUMENT_I64:
219 case WebAssembly::ARGUMENT_F32:
220 case WebAssembly::ARGUMENT_F64:
221 // These represent values which are live into the function entry, so there's
222 // no instruction to emit.
224 case WebAssembly::LOOP_END:
225 // This is a no-op which just exists to tell AsmPrinter.cpp that there's a
226 // fallthrough which nevertheless requires a label for the destination here.
229 WebAssemblyMCInstLower MCInstLowering(OutContext, *this);
231 MCInstLowering.Lower(MI, TmpInst);
232 EmitToStreamer(*OutStreamer, TmpInst);
238 void WebAssemblyAsmPrinter::EmitEndOfAsmFile(Module &M) {
239 const DataLayout &DL = M.getDataLayout();
241 SmallString<128> Str;
242 raw_svector_ostream OS(Str);
243 for (const Function &F : M)
244 if (F.isDeclarationForLinker()) {
245 assert(F.hasName() && "imported functions must have a name");
249 OS << "\t.imports\n";
251 MCSymbol *Sym = OutStreamer->getContext().getOrCreateSymbol(F.getName());
252 OS << "\t.import " << *Sym << " \"\" " << *Sym;
254 const WebAssemblyTargetLowering &TLI =
255 *TM.getSubtarget<WebAssemblySubtarget>(F).getTargetLowering();
257 // If we need to legalize the return type, it'll get converted into
258 // passing a pointer.
259 bool SawParam = false;
260 SmallVector<MVT, 4> ResultVTs;
261 ComputeLegalValueVTs(F, TM, F.getReturnType(), ResultVTs);
262 if (ResultVTs.size() > 1) {
264 OS << " (param " << toString(TLI.getPointerTy(DL));
268 for (const Argument &A : F.args()) {
269 SmallVector<MVT, 4> ParamVTs;
270 ComputeLegalValueVTs(F, TM, A.getType(), ParamVTs);
271 for (MVT VT : ParamVTs) {
276 OS << ' ' << toString(VT);
282 for (MVT VT : ResultVTs)
283 OS << " (result " << toString(VT) << ')';
288 StringRef Text = OS.str();
290 OutStreamer->EmitRawText(Text.substr(0, Text.size() - 1));
292 AsmPrinter::EmitEndOfAsmFile(M);
295 bool WebAssemblyAsmPrinter::PrintAsmOperand(const MachineInstr *MI,
296 unsigned OpNo, unsigned AsmVariant,
297 const char *ExtraCode,
300 report_fatal_error("There are no defined alternate asm variants");
303 const MachineOperand &MO = MI->getOperand(OpNo);
307 OS << regToString(MO);
311 return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
314 bool WebAssemblyAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
317 const char *ExtraCode,
320 report_fatal_error("There are no defined alternate asm variants");
323 OS << regToString(MI->getOperand(OpNo));
327 return AsmPrinter::PrintAsmMemoryOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
330 // Force static initialization.
331 extern "C" void LLVMInitializeWebAssemblyAsmPrinter() {
332 RegisterAsmPrinter<WebAssemblyAsmPrinter> X(TheWebAssemblyTarget32);
333 RegisterAsmPrinter<WebAssemblyAsmPrinter> Y(TheWebAssemblyTarget64);