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 bool runOnMachineFunction(MachineFunction &MF) override {
61 MRI = &MF.getRegInfo();
62 MFI = MF.getInfo<WebAssemblyFunctionInfo>();
63 return AsmPrinter::runOnMachineFunction(MF);
66 //===------------------------------------------------------------------===//
67 // AsmPrinter Implementation.
68 //===------------------------------------------------------------------===//
70 void EmitJumpTableInfo() override;
71 void EmitConstantPool() override;
72 void EmitFunctionBodyStart() override;
73 void EmitInstruction(const MachineInstr *MI) override;
74 void EmitEndOfAsmFile(Module &M) override;
75 bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
76 unsigned AsmVariant, const char *ExtraCode,
77 raw_ostream &OS) override;
78 bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
79 unsigned AsmVariant, const char *ExtraCode,
80 raw_ostream &OS) override;
82 MVT getRegType(unsigned RegNo) const;
83 const char *toString(MVT VT) const;
84 std::string regToString(const MachineOperand &MO);
87 } // end anonymous namespace
89 //===----------------------------------------------------------------------===//
91 //===----------------------------------------------------------------------===//
93 MVT WebAssemblyAsmPrinter::getRegType(unsigned RegNo) const {
94 const TargetRegisterClass *TRC = MRI->getRegClass(RegNo);
95 for (MVT T : {MVT::i32, MVT::i64, MVT::f32, MVT::f64})
98 DEBUG(errs() << "Unknown type for register number: " << RegNo);
99 llvm_unreachable("Unknown register type");
103 std::string WebAssemblyAsmPrinter::regToString(const MachineOperand &MO) {
104 unsigned RegNo = MO.getReg();
105 assert(TargetRegisterInfo::isVirtualRegister(RegNo) &&
106 "Unlowered physical register encountered during assembly printing");
107 assert(!MFI->isVRegStackified(RegNo));
108 unsigned WAReg = MFI->getWAReg(RegNo);
109 assert(WAReg != WebAssemblyFunctionInfo::UnusedReg);
110 return '$' + utostr(WAReg);
113 const char *WebAssemblyAsmPrinter::toString(MVT VT) const {
114 return WebAssembly::TypeToString(VT);
117 //===----------------------------------------------------------------------===//
118 // WebAssemblyAsmPrinter Implementation.
119 //===----------------------------------------------------------------------===//
121 void WebAssemblyAsmPrinter::EmitConstantPool() {
122 assert(MF->getConstantPool()->getConstants().empty() &&
123 "WebAssembly disables constant pools");
126 void WebAssemblyAsmPrinter::EmitJumpTableInfo() {
127 // Nothing to do; jump tables are incorporated into the instruction stream.
130 static void ComputeLegalValueVTs(const Function &F, const TargetMachine &TM,
131 Type *Ty, SmallVectorImpl<MVT> &ValueVTs) {
132 const DataLayout &DL(F.getParent()->getDataLayout());
133 const WebAssemblyTargetLowering &TLI =
134 *TM.getSubtarget<WebAssemblySubtarget>(F).getTargetLowering();
135 SmallVector<EVT, 4> VTs;
136 ComputeValueVTs(TLI, DL, Ty, VTs);
139 unsigned NumRegs = TLI.getNumRegisters(F.getContext(), VT);
140 MVT RegisterVT = TLI.getRegisterType(F.getContext(), VT);
141 for (unsigned i = 0; i != NumRegs; ++i)
142 ValueVTs.push_back(RegisterVT);
146 void WebAssemblyAsmPrinter::EmitFunctionBodyStart() {
147 if (!MFI->getParams().empty()) {
149 Param.setOpcode(WebAssembly::PARAM);
150 for (MVT VT : MFI->getParams())
151 Param.addOperand(MCOperand::createImm(VT.SimpleTy));
152 EmitToStreamer(*OutStreamer, Param);
155 SmallVector<MVT, 4> ResultVTs;
156 const Function &F(*MF->getFunction());
157 ComputeLegalValueVTs(F, TM, F.getReturnType(), ResultVTs);
158 // If the return type needs to be legalized it will get converted into
159 // passing a pointer.
160 if (ResultVTs.size() == 1) {
162 Result.setOpcode(WebAssembly::RESULT);
163 Result.addOperand(MCOperand::createImm(ResultVTs.front().SimpleTy));
164 EmitToStreamer(*OutStreamer, Result);
167 bool AnyWARegs = false;
169 Local.setOpcode(WebAssembly::LOCAL);
170 for (unsigned Idx = 0, IdxE = MRI->getNumVirtRegs(); Idx != IdxE; ++Idx) {
171 unsigned VReg = TargetRegisterInfo::index2VirtReg(Idx);
172 unsigned WAReg = MFI->getWAReg(VReg);
173 // Don't declare unused registers.
174 if (WAReg == WebAssemblyFunctionInfo::UnusedReg)
176 // Don't redeclare parameters.
177 if (WAReg < MFI->getParams().size())
179 // Don't declare stackified registers.
182 Local.addOperand(MCOperand::createImm(getRegType(VReg).SimpleTy));
186 EmitToStreamer(*OutStreamer, Local);
188 AsmPrinter::EmitFunctionBodyStart();
191 void WebAssemblyAsmPrinter::EmitInstruction(const MachineInstr *MI) {
192 DEBUG(dbgs() << "EmitInstruction: " << *MI << '\n');
194 switch (MI->getOpcode()) {
195 case WebAssembly::ARGUMENT_I32:
196 case WebAssembly::ARGUMENT_I64:
197 case WebAssembly::ARGUMENT_F32:
198 case WebAssembly::ARGUMENT_F64:
199 // These represent values which are live into the function entry, so there's
200 // no instruction to emit.
202 case WebAssembly::LOOP_END:
203 // This is a no-op which just exists to tell AsmPrinter.cpp that there's a
204 // fallthrough which nevertheless requires a label for the destination here.
207 WebAssemblyMCInstLower MCInstLowering(OutContext, *this);
209 MCInstLowering.Lower(MI, TmpInst);
210 EmitToStreamer(*OutStreamer, TmpInst);
216 void WebAssemblyAsmPrinter::EmitEndOfAsmFile(Module &M) {
217 const DataLayout &DL = M.getDataLayout();
219 SmallString<128> Str;
220 raw_svector_ostream OS(Str);
221 for (const Function &F : M)
222 if (F.isDeclarationForLinker()) {
223 assert(F.hasName() && "imported functions must have a name");
227 OS << "\t.imports\n";
229 MCSymbol *Sym = OutStreamer->getContext().getOrCreateSymbol(F.getName());
230 OS << "\t.import " << *Sym << " \"\" " << *Sym;
232 const WebAssemblyTargetLowering &TLI =
233 *TM.getSubtarget<WebAssemblySubtarget>(F).getTargetLowering();
235 // If we need to legalize the return type, it'll get converted into
236 // passing a pointer.
237 bool SawParam = false;
238 SmallVector<MVT, 4> ResultVTs;
239 ComputeLegalValueVTs(F, TM, F.getReturnType(), ResultVTs);
240 if (ResultVTs.size() > 1) {
242 OS << " (param " << toString(TLI.getPointerTy(DL));
246 for (const Argument &A : F.args()) {
247 SmallVector<MVT, 4> ParamVTs;
248 ComputeLegalValueVTs(F, TM, A.getType(), ParamVTs);
249 for (MVT VT : ParamVTs) {
254 OS << ' ' << toString(VT);
260 for (MVT VT : ResultVTs)
261 OS << " (result " << toString(VT) << ')';
266 StringRef Text = OS.str();
268 OutStreamer->EmitRawText(Text.substr(0, Text.size() - 1));
270 AsmPrinter::EmitEndOfAsmFile(M);
273 bool WebAssemblyAsmPrinter::PrintAsmOperand(const MachineInstr *MI,
274 unsigned OpNo, unsigned AsmVariant,
275 const char *ExtraCode,
278 report_fatal_error("There are no defined alternate asm variants");
281 const MachineOperand &MO = MI->getOperand(OpNo);
285 OS << regToString(MO);
289 return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
292 bool WebAssemblyAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
295 const char *ExtraCode,
298 report_fatal_error("There are no defined alternate asm variants");
301 OS << regToString(MI->getOperand(OpNo));
305 return AsmPrinter::PrintAsmMemoryOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
308 // Force static initialization.
309 extern "C" void LLVMInitializeWebAssemblyAsmPrinter() {
310 RegisterAsmPrinter<WebAssemblyAsmPrinter> X(TheWebAssemblyTarget32);
311 RegisterAsmPrinter<WebAssemblyAsmPrinter> Y(TheWebAssemblyTarget64);