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"
39 #define DEBUG_TYPE "asm-printer"
43 class WebAssemblyAsmPrinter final : public AsmPrinter {
44 const MachineRegisterInfo *MRI;
45 const WebAssemblyFunctionInfo *MFI;
48 WebAssemblyAsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
49 : AsmPrinter(TM, std::move(Streamer)), MRI(nullptr), MFI(nullptr) {}
52 const char *getPassName() const override {
53 return "WebAssembly Assembly Printer";
56 //===------------------------------------------------------------------===//
57 // MachineFunctionPass Implementation.
58 //===------------------------------------------------------------------===//
60 void getAnalysisUsage(AnalysisUsage &AU) const override {
61 AsmPrinter::getAnalysisUsage(AU);
64 bool runOnMachineFunction(MachineFunction &MF) override {
65 MRI = &MF.getRegInfo();
66 MFI = MF.getInfo<WebAssemblyFunctionInfo>();
67 return AsmPrinter::runOnMachineFunction(MF);
70 //===------------------------------------------------------------------===//
71 // AsmPrinter Implementation.
72 //===------------------------------------------------------------------===//
74 void EmitJumpTableInfo() override;
75 void EmitConstantPool() override;
76 void EmitFunctionBodyStart() override;
77 void EmitInstruction(const MachineInstr *MI) override;
78 void EmitEndOfAsmFile(Module &M) override;
79 bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
80 unsigned AsmVariant, const char *ExtraCode,
81 raw_ostream &OS) override;
82 bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
83 unsigned AsmVariant, const char *ExtraCode,
84 raw_ostream &OS) override;
86 MVT getRegType(unsigned RegNo) const;
87 const char *toString(MVT VT) const;
88 std::string regToString(const MachineOperand &MO);
91 } // end anonymous namespace
93 //===----------------------------------------------------------------------===//
95 //===----------------------------------------------------------------------===//
97 MVT WebAssemblyAsmPrinter::getRegType(unsigned RegNo) const {
98 const TargetRegisterClass *TRC = MRI->getRegClass(RegNo);
99 for (MVT T : {MVT::i32, MVT::i64, MVT::f32, MVT::f64})
102 DEBUG(errs() << "Unknown type for register number: " << RegNo);
103 llvm_unreachable("Unknown register type");
107 std::string WebAssemblyAsmPrinter::regToString(const MachineOperand &MO) {
108 unsigned RegNo = MO.getReg();
109 assert(TargetRegisterInfo::isVirtualRegister(RegNo) &&
110 "Unlowered physical register encountered during assembly printing");
111 assert(!MFI->isVRegStackified(RegNo));
112 unsigned WAReg = MFI->getWAReg(RegNo);
113 assert(WAReg != WebAssemblyFunctionInfo::UnusedReg);
114 return '$' + utostr(WAReg);
117 const char *WebAssemblyAsmPrinter::toString(MVT VT) const {
118 switch (VT.SimpleTy) {
130 DEBUG(dbgs() << "Invalid type " << EVT(VT).getEVTString() << '\n');
131 llvm_unreachable("invalid type");
135 //===----------------------------------------------------------------------===//
136 // WebAssemblyAsmPrinter Implementation.
137 //===----------------------------------------------------------------------===//
139 void WebAssemblyAsmPrinter::EmitConstantPool() {
140 assert(MF->getConstantPool()->getConstants().empty() &&
141 "WebAssembly disables constant pools");
144 void WebAssemblyAsmPrinter::EmitJumpTableInfo() {
145 // Nothing to do; jump tables are incorporated into the instruction stream.
148 static void ComputeLegalValueVTs(const Function &F,
149 const TargetMachine &TM,
151 SmallVectorImpl<MVT> &ValueVTs) {
152 const DataLayout& DL(F.getParent()->getDataLayout());
153 const WebAssemblyTargetLowering &TLI =
154 *TM.getSubtarget<WebAssemblySubtarget>(F).getTargetLowering();
155 SmallVector<EVT, 4> VTs;
156 ComputeValueVTs(TLI, DL, Ty, VTs);
159 unsigned NumRegs = TLI.getNumRegisters(F.getContext(), VT);
160 MVT RegisterVT = TLI.getRegisterType(F.getContext(), VT);
161 for (unsigned i = 0; i != NumRegs; ++i)
162 ValueVTs.push_back(RegisterVT);
166 void WebAssemblyAsmPrinter::EmitFunctionBodyStart() {
167 if (!MFI->getParams().empty()) {
169 Param.setOpcode(WebAssembly::PARAM);
170 for (MVT VT : MFI->getParams())
171 Param.addOperand(MCOperand::createImm(VT.SimpleTy));
172 EmitToStreamer(*OutStreamer, Param);
176 SmallVector<MVT, 4> ResultVTs;
177 const Function &F(*MF->getFunction());
178 ComputeLegalValueVTs(F, TM, F.getReturnType(), ResultVTs);
179 // If the return type needs to be legalized it will get converted into
180 // passing a pointer.
181 if (ResultVTs.size() == 1) {
183 Result.setOpcode(WebAssembly::RESULT);
184 Result.addOperand(MCOperand::createImm(ResultVTs.front().SimpleTy));
185 EmitToStreamer(*OutStreamer, Result);
188 bool AnyWARegs = false;
190 Local.setOpcode(WebAssembly::LOCAL);
191 for (unsigned Idx = 0, IdxE = MRI->getNumVirtRegs(); Idx != IdxE; ++Idx) {
192 unsigned VReg = TargetRegisterInfo::index2VirtReg(Idx);
193 unsigned WAReg = MFI->getWAReg(VReg);
194 // Don't declare unused registers.
195 if (WAReg == WebAssemblyFunctionInfo::UnusedReg)
197 // Don't redeclare parameters.
198 if (WAReg < MFI->getParams().size())
200 // Don't declare stackified registers.
203 Local.addOperand(MCOperand::createImm(getRegType(VReg).SimpleTy));
207 EmitToStreamer(*OutStreamer, Local);
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.
223 case WebAssembly::LOOP_END:
224 // This is a no-op which just exists to tell AsmPrinter.cpp that there's a
225 // fallthrough which nevertheless requires a label for the destination here.
228 WebAssemblyMCInstLower MCInstLowering(OutContext, *this);
230 MCInstLowering.Lower(MI, TmpInst);
231 EmitToStreamer(*OutStreamer, TmpInst);
237 void WebAssemblyAsmPrinter::EmitEndOfAsmFile(Module &M) {
238 const DataLayout &DL = M.getDataLayout();
240 SmallString<128> Str;
241 raw_svector_ostream OS(Str);
242 for (const Function &F : M)
243 if (F.isDeclarationForLinker()) {
244 assert(F.hasName() && "imported functions must have a name");
248 OS << "\t.imports\n";
250 MCSymbol *Sym = OutStreamer->getContext().getOrCreateSymbol(F.getName());
251 OS << "\t.import " << *Sym << " \"\" " << *Sym;
253 const WebAssemblyTargetLowering &TLI =
254 *TM.getSubtarget<WebAssemblySubtarget>(F).getTargetLowering();
256 // If we need to legalize the return type, it'll get converted into
257 // passing a pointer.
258 bool SawParam = false;
259 SmallVector<MVT, 4> ResultVTs;
260 ComputeLegalValueVTs(F, TM, F.getReturnType(), ResultVTs);
261 if (ResultVTs.size() > 1) {
263 OS << " (param " << toString(TLI.getPointerTy(DL));
267 for (const Argument &A : F.args()) {
268 SmallVector<MVT, 4> ParamVTs;
269 ComputeLegalValueVTs(F, TM, A.getType(), ParamVTs);
270 for (MVT VT : ParamVTs) {
275 OS << ' ' << toString(VT);
281 for (MVT VT : ResultVTs)
282 OS << " (result " << toString(VT) << ')';
287 StringRef Text = OS.str();
289 OutStreamer->EmitRawText(Text.substr(0, Text.size() - 1));
291 AsmPrinter::EmitEndOfAsmFile(M);
294 bool WebAssemblyAsmPrinter::PrintAsmOperand(const MachineInstr *MI,
295 unsigned OpNo, unsigned AsmVariant,
296 const char *ExtraCode,
299 report_fatal_error("There are no defined alternate asm variants");
302 const MachineOperand &MO = MI->getOperand(OpNo);
306 OS << regToString(MO);
310 return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
313 bool WebAssemblyAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
316 const char *ExtraCode,
319 report_fatal_error("There are no defined alternate asm variants");
322 OS << regToString(MI->getOperand(OpNo));
326 return AsmPrinter::PrintAsmMemoryOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
329 // Force static initialization.
330 extern "C" void LLVMInitializeWebAssemblyAsmPrinter() {
331 RegisterAsmPrinter<WebAssemblyAsmPrinter> X(TheWebAssemblyTarget32);
332 RegisterAsmPrinter<WebAssemblyAsmPrinter> Y(TheWebAssemblyTarget64);