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 std::string getRegTypeName(unsigned RegNo) const;
88 const char *toString(MVT VT) const;
89 std::string regToString(const MachineOperand &MO);
92 } // end anonymous namespace
94 //===----------------------------------------------------------------------===//
96 //===----------------------------------------------------------------------===//
98 std::string WebAssemblyAsmPrinter::getRegTypeName(unsigned RegNo) const {
99 const TargetRegisterClass *TRC = MRI->getRegClass(RegNo);
100 for (MVT T : {MVT::i32, MVT::i64, MVT::f32, MVT::f64})
102 return EVT(T).getEVTString();
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 SmallString<128> Str;
169 raw_svector_ostream OS(Str);
171 for (MVT VT : MFI->getParams())
172 OS << "\t" ".param " << toString(VT) << '\n';
174 SmallVector<MVT, 4> ResultVTs;
175 const Function &F(*MF->getFunction());
176 ComputeLegalValueVTs(F, TM, F.getReturnType(), ResultVTs);
177 // If the return type needs to be legalized it will get converted into
178 // passing a pointer.
179 if (ResultVTs.size() == 1)
180 OS << "\t" ".result " << toString(ResultVTs.front()) << '\n';
182 bool FirstWAReg = true;
183 for (unsigned Idx = 0, IdxE = MRI->getNumVirtRegs(); Idx != IdxE; ++Idx) {
184 unsigned VReg = TargetRegisterInfo::index2VirtReg(Idx);
185 unsigned WAReg = MFI->getWAReg(VReg);
186 // Don't declare unused registers.
187 if (WAReg == WebAssemblyFunctionInfo::UnusedReg)
189 // Don't redeclare parameters.
190 if (WAReg < MFI->getParams().size())
192 // Don't declare stackified registers.
196 OS << "\t" ".local ";
199 OS << getRegTypeName(VReg);
205 // EmitRawText appends a newline, so strip off the last newline.
206 StringRef Text = OS.str();
208 OutStreamer->EmitRawText(Text.substr(0, Text.size() - 1));
209 AsmPrinter::EmitFunctionBodyStart();
212 void WebAssemblyAsmPrinter::EmitInstruction(const MachineInstr *MI) {
213 DEBUG(dbgs() << "EmitInstruction: " << *MI << '\n');
215 switch (MI->getOpcode()) {
216 case WebAssembly::ARGUMENT_I32:
217 case WebAssembly::ARGUMENT_I64:
218 case WebAssembly::ARGUMENT_F32:
219 case WebAssembly::ARGUMENT_F64:
220 // These represent values which are live into the function entry, so there's
221 // no instruction to emit.
224 WebAssemblyMCInstLower MCInstLowering(OutContext, *this);
226 MCInstLowering.Lower(MI, TmpInst);
227 EmitToStreamer(*OutStreamer, TmpInst);
233 void WebAssemblyAsmPrinter::EmitEndOfAsmFile(Module &M) {
234 const DataLayout &DL = M.getDataLayout();
236 SmallString<128> Str;
237 raw_svector_ostream OS(Str);
238 for (const Function &F : M)
239 if (F.isDeclarationForLinker()) {
240 assert(F.hasName() && "imported functions must have a name");
244 OS << "\t.imports\n";
246 MCSymbol *Sym = OutStreamer->getContext().getOrCreateSymbol(F.getName());
247 OS << "\t.import " << *Sym << " \"\" " << *Sym;
249 const WebAssemblyTargetLowering &TLI =
250 *TM.getSubtarget<WebAssemblySubtarget>(F).getTargetLowering();
252 // If we need to legalize the return type, it'll get converted into
253 // passing a pointer.
254 bool SawParam = false;
255 SmallVector<MVT, 4> ResultVTs;
256 ComputeLegalValueVTs(F, TM, F.getReturnType(), ResultVTs);
257 if (ResultVTs.size() > 1) {
259 OS << " (param " << toString(TLI.getPointerTy(DL));
263 for (const Argument &A : F.args()) {
264 SmallVector<MVT, 4> ParamVTs;
265 ComputeLegalValueVTs(F, TM, A.getType(), ParamVTs);
266 for (MVT VT : ParamVTs) {
271 OS << ' ' << toString(VT);
277 for (MVT VT : ResultVTs)
278 OS << " (result " << toString(VT) << ')';
283 StringRef Text = OS.str();
285 OutStreamer->EmitRawText(Text.substr(0, Text.size() - 1));
288 bool WebAssemblyAsmPrinter::PrintAsmOperand(const MachineInstr *MI,
289 unsigned OpNo, unsigned AsmVariant,
290 const char *ExtraCode,
293 report_fatal_error("There are no defined alternate asm variants");
296 const MachineOperand &MO = MI->getOperand(OpNo);
300 OS << regToString(MO);
304 return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
307 bool WebAssemblyAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
310 const char *ExtraCode,
313 report_fatal_error("There are no defined alternate asm variants");
316 OS << regToString(MI->getOperand(OpNo));
320 return AsmPrinter::PrintAsmMemoryOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
323 // Force static initialization.
324 extern "C" void LLVMInitializeWebAssemblyAsmPrinter() {
325 RegisterAsmPrinter<WebAssemblyAsmPrinter> X(TheWebAssemblyTarget32);
326 RegisterAsmPrinter<WebAssemblyAsmPrinter> Y(TheWebAssemblyTarget64);