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 return WebAssembly::TypeToString(VT);
121 //===----------------------------------------------------------------------===//
122 // WebAssemblyAsmPrinter Implementation.
123 //===----------------------------------------------------------------------===//
125 void WebAssemblyAsmPrinter::EmitConstantPool() {
126 assert(MF->getConstantPool()->getConstants().empty() &&
127 "WebAssembly disables constant pools");
130 void WebAssemblyAsmPrinter::EmitJumpTableInfo() {
131 // Nothing to do; jump tables are incorporated into the instruction stream.
134 static void ComputeLegalValueVTs(const Function &F, const TargetMachine &TM,
135 Type *Ty, SmallVectorImpl<MVT> &ValueVTs) {
136 const DataLayout &DL(F.getParent()->getDataLayout());
137 const WebAssemblyTargetLowering &TLI =
138 *TM.getSubtarget<WebAssemblySubtarget>(F).getTargetLowering();
139 SmallVector<EVT, 4> VTs;
140 ComputeValueVTs(TLI, DL, Ty, VTs);
143 unsigned NumRegs = TLI.getNumRegisters(F.getContext(), VT);
144 MVT RegisterVT = TLI.getRegisterType(F.getContext(), VT);
145 for (unsigned i = 0; i != NumRegs; ++i)
146 ValueVTs.push_back(RegisterVT);
150 void WebAssemblyAsmPrinter::EmitFunctionBodyStart() {
151 if (!MFI->getParams().empty()) {
153 Param.setOpcode(WebAssembly::PARAM);
154 for (MVT VT : MFI->getParams())
155 Param.addOperand(MCOperand::createImm(VT.SimpleTy));
156 EmitToStreamer(*OutStreamer, Param);
159 SmallVector<MVT, 4> ResultVTs;
160 const Function &F(*MF->getFunction());
161 ComputeLegalValueVTs(F, TM, F.getReturnType(), ResultVTs);
162 // If the return type needs to be legalized it will get converted into
163 // passing a pointer.
164 if (ResultVTs.size() == 1) {
166 Result.setOpcode(WebAssembly::RESULT);
167 Result.addOperand(MCOperand::createImm(ResultVTs.front().SimpleTy));
168 EmitToStreamer(*OutStreamer, Result);
171 bool AnyWARegs = false;
173 Local.setOpcode(WebAssembly::LOCAL);
174 for (unsigned Idx = 0, IdxE = MRI->getNumVirtRegs(); Idx != IdxE; ++Idx) {
175 unsigned VReg = TargetRegisterInfo::index2VirtReg(Idx);
176 unsigned WAReg = MFI->getWAReg(VReg);
177 // Don't declare unused registers.
178 if (WAReg == WebAssemblyFunctionInfo::UnusedReg)
180 // Don't redeclare parameters.
181 if (WAReg < MFI->getParams().size())
183 // Don't declare stackified registers.
186 Local.addOperand(MCOperand::createImm(getRegType(VReg).SimpleTy));
190 EmitToStreamer(*OutStreamer, Local);
192 AsmPrinter::EmitFunctionBodyStart();
195 void WebAssemblyAsmPrinter::EmitInstruction(const MachineInstr *MI) {
196 DEBUG(dbgs() << "EmitInstruction: " << *MI << '\n');
198 switch (MI->getOpcode()) {
199 case WebAssembly::ARGUMENT_I32:
200 case WebAssembly::ARGUMENT_I64:
201 case WebAssembly::ARGUMENT_F32:
202 case WebAssembly::ARGUMENT_F64:
203 // These represent values which are live into the function entry, so there's
204 // no instruction to emit.
206 case WebAssembly::LOOP_END:
207 // This is a no-op which just exists to tell AsmPrinter.cpp that there's a
208 // fallthrough which nevertheless requires a label for the destination here.
211 WebAssemblyMCInstLower MCInstLowering(OutContext, *this);
213 MCInstLowering.Lower(MI, TmpInst);
214 EmitToStreamer(*OutStreamer, TmpInst);
220 void WebAssemblyAsmPrinter::EmitEndOfAsmFile(Module &M) {
221 const DataLayout &DL = M.getDataLayout();
223 SmallString<128> Str;
224 raw_svector_ostream OS(Str);
225 for (const Function &F : M)
226 if (F.isDeclarationForLinker()) {
227 assert(F.hasName() && "imported functions must have a name");
231 OS << "\t.imports\n";
233 MCSymbol *Sym = OutStreamer->getContext().getOrCreateSymbol(F.getName());
234 OS << "\t.import " << *Sym << " \"\" " << *Sym;
236 const WebAssemblyTargetLowering &TLI =
237 *TM.getSubtarget<WebAssemblySubtarget>(F).getTargetLowering();
239 // If we need to legalize the return type, it'll get converted into
240 // passing a pointer.
241 bool SawParam = false;
242 SmallVector<MVT, 4> ResultVTs;
243 ComputeLegalValueVTs(F, TM, F.getReturnType(), ResultVTs);
244 if (ResultVTs.size() > 1) {
246 OS << " (param " << toString(TLI.getPointerTy(DL));
250 for (const Argument &A : F.args()) {
251 SmallVector<MVT, 4> ParamVTs;
252 ComputeLegalValueVTs(F, TM, A.getType(), ParamVTs);
253 for (MVT VT : ParamVTs) {
258 OS << ' ' << toString(VT);
264 for (MVT VT : ResultVTs)
265 OS << " (result " << toString(VT) << ')';
270 StringRef Text = OS.str();
272 OutStreamer->EmitRawText(Text.substr(0, Text.size() - 1));
274 AsmPrinter::EmitEndOfAsmFile(M);
277 bool WebAssemblyAsmPrinter::PrintAsmOperand(const MachineInstr *MI,
278 unsigned OpNo, unsigned AsmVariant,
279 const char *ExtraCode,
282 report_fatal_error("There are no defined alternate asm variants");
285 const MachineOperand &MO = MI->getOperand(OpNo);
289 OS << regToString(MO);
293 return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
296 bool WebAssemblyAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
299 const char *ExtraCode,
302 report_fatal_error("There are no defined alternate asm variants");
305 OS << regToString(MI->getOperand(OpNo));
309 return AsmPrinter::PrintAsmMemoryOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
312 // Force static initialization.
313 extern "C" void LLVMInitializeWebAssemblyAsmPrinter() {
314 RegisterAsmPrinter<WebAssemblyAsmPrinter> X(TheWebAssemblyTarget32);
315 RegisterAsmPrinter<WebAssemblyAsmPrinter> Y(TheWebAssemblyTarget64);