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 "InstPrinter/WebAssemblyInstPrinter.h"
18 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
19 #include "MCTargetDesc/WebAssemblyTargetStreamer.h"
20 #include "WebAssembly.h"
21 #include "WebAssemblyMCInstLower.h"
22 #include "WebAssemblyMachineFunctionInfo.h"
23 #include "WebAssemblyRegisterInfo.h"
24 #include "WebAssemblySubtarget.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 WebAssemblyFunctionInfo *MFI;
48 WebAssemblyAsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
49 : AsmPrinter(TM, std::move(Streamer)), MRI(nullptr), MFI(nullptr) {}
52 StringRef 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 EmitEndOfAsmFile(Module &M) override;
71 void EmitJumpTableInfo() override;
72 void EmitConstantPool() override;
73 void EmitFunctionBodyStart() override;
74 void EmitFunctionBodyEnd() override;
75 void EmitInstruction(const MachineInstr *MI) override;
76 const MCExpr *lowerConstant(const Constant *CV) override;
77 bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
78 unsigned AsmVariant, const char *ExtraCode,
79 raw_ostream &OS) override;
80 bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
81 unsigned AsmVariant, const char *ExtraCode,
82 raw_ostream &OS) override;
84 MVT getRegType(unsigned RegNo) const;
85 std::string regToString(const MachineOperand &MO);
86 WebAssemblyTargetStreamer *getTargetStreamer();
89 } // end anonymous namespace
91 //===----------------------------------------------------------------------===//
93 //===----------------------------------------------------------------------===//
95 MVT WebAssemblyAsmPrinter::getRegType(unsigned RegNo) const {
96 const TargetRegisterClass *TRC = MRI->getRegClass(RegNo);
97 for (MVT T : {MVT::i32, MVT::i64, MVT::f32, MVT::f64, MVT::v16i8, MVT::v8i16,
98 MVT::v4i32, MVT::v4f32})
101 DEBUG(errs() << "Unknown type for register number: " << RegNo);
102 llvm_unreachable("Unknown register type");
106 std::string WebAssemblyAsmPrinter::regToString(const MachineOperand &MO) {
107 unsigned RegNo = MO.getReg();
108 assert(TargetRegisterInfo::isVirtualRegister(RegNo) &&
109 "Unlowered physical register encountered during assembly printing");
110 assert(!MFI->isVRegStackified(RegNo));
111 unsigned WAReg = MFI->getWAReg(RegNo);
112 assert(WAReg != WebAssemblyFunctionInfo::UnusedReg);
113 return '$' + utostr(WAReg);
116 WebAssemblyTargetStreamer *WebAssemblyAsmPrinter::getTargetStreamer() {
117 MCTargetStreamer *TS = OutStreamer->getTargetStreamer();
118 return static_cast<WebAssemblyTargetStreamer *>(TS);
121 //===----------------------------------------------------------------------===//
122 // WebAssemblyAsmPrinter Implementation.
123 //===----------------------------------------------------------------------===//
125 void WebAssemblyAsmPrinter::EmitEndOfAsmFile(Module &M) {
126 for (const auto &F : M) {
127 // Emit function type info for all undefined functions
128 if (F.isDeclarationForLinker() && !F.isIntrinsic()) {
129 SmallVector<MVT, 4> Results;
130 SmallVector<MVT, 4> Params;
131 ComputeSignatureVTs(F, TM, Params, Results);
132 getTargetStreamer()->emitIndirectFunctionType(F.getName(), Params,
136 for (const auto &G : M.globals()) {
137 if (!G.hasInitializer() && G.hasExternalLinkage()) {
138 getTargetStreamer()->emitGlobalImport(G.getGlobalIdentifier());
143 void WebAssemblyAsmPrinter::EmitConstantPool() {
144 assert(MF->getConstantPool()->getConstants().empty() &&
145 "WebAssembly disables constant pools");
148 void WebAssemblyAsmPrinter::EmitJumpTableInfo() {
149 // Nothing to do; jump tables are incorporated into the instruction stream.
152 void WebAssemblyAsmPrinter::EmitFunctionBodyStart() {
153 if (!MFI->getParams().empty())
154 getTargetStreamer()->emitParam(MFI->getParams());
156 SmallVector<MVT, 4> ResultVTs;
157 const Function &F(*MF->getFunction());
159 // Emit the function index.
160 if (MDNode *Idx = F.getMetadata("wasm.index")) {
161 assert(Idx->getNumOperands() == 1);
163 getTargetStreamer()->emitIndIdx(AsmPrinter::lowerConstant(
164 cast<ConstantAsMetadata>(Idx->getOperand(0))->getValue()));
167 ComputeLegalValueVTs(F, TM, F.getReturnType(), ResultVTs);
169 // If the return type needs to be legalized it will get converted into
170 // passing a pointer.
171 if (ResultVTs.size() == 1)
172 getTargetStreamer()->emitResult(ResultVTs);
174 // FIXME: When ExplicitLocals is enabled by default, we won't need
175 // to define the locals here (and MFI can go back to being pointer-to-const).
176 for (unsigned Idx = 0, IdxE = MRI->getNumVirtRegs(); Idx != IdxE; ++Idx) {
177 unsigned VReg = TargetRegisterInfo::index2VirtReg(Idx);
178 unsigned WAReg = MFI->getWAReg(VReg);
179 // Don't declare unused registers.
180 if (WAReg == WebAssemblyFunctionInfo::UnusedReg)
182 // Don't redeclare parameters.
183 if (WAReg < MFI->getParams().size())
185 // Don't declare stackified registers.
188 MFI->addLocal(getRegType(VReg));
191 getTargetStreamer()->emitLocal(MFI->getLocals());
193 AsmPrinter::EmitFunctionBodyStart();
196 void WebAssemblyAsmPrinter::EmitFunctionBodyEnd() {
197 getTargetStreamer()->emitEndFunc();
200 void WebAssemblyAsmPrinter::EmitInstruction(const MachineInstr *MI) {
201 DEBUG(dbgs() << "EmitInstruction: " << *MI << '\n');
203 switch (MI->getOpcode()) {
204 case WebAssembly::ARGUMENT_I32:
205 case WebAssembly::ARGUMENT_I64:
206 case WebAssembly::ARGUMENT_F32:
207 case WebAssembly::ARGUMENT_F64:
208 case WebAssembly::ARGUMENT_v16i8:
209 case WebAssembly::ARGUMENT_v8i16:
210 case WebAssembly::ARGUMENT_v4i32:
211 case WebAssembly::ARGUMENT_v4f32:
212 // These represent values which are live into the function entry, so there's
213 // no instruction to emit.
215 case WebAssembly::FALLTHROUGH_RETURN_I32:
216 case WebAssembly::FALLTHROUGH_RETURN_I64:
217 case WebAssembly::FALLTHROUGH_RETURN_F32:
218 case WebAssembly::FALLTHROUGH_RETURN_F64:
219 case WebAssembly::FALLTHROUGH_RETURN_v16i8:
220 case WebAssembly::FALLTHROUGH_RETURN_v8i16:
221 case WebAssembly::FALLTHROUGH_RETURN_v4i32:
222 case WebAssembly::FALLTHROUGH_RETURN_v4f32: {
223 // These instructions represent the implicit return at the end of a
224 // function body. The operand is always a pop.
225 assert(MFI->isVRegStackified(MI->getOperand(0).getReg()));
228 OutStreamer->AddComment("fallthrough-return: $pop" +
229 utostr(MFI->getWARegStackId(
230 MFI->getWAReg(MI->getOperand(0).getReg()))));
231 OutStreamer->AddBlankLine();
235 case WebAssembly::FALLTHROUGH_RETURN_VOID:
236 // This instruction represents the implicit return at the end of a
237 // function body with no return value.
239 OutStreamer->AddComment("fallthrough-return");
240 OutStreamer->AddBlankLine();
244 WebAssemblyMCInstLower MCInstLowering(OutContext, *this);
246 MCInstLowering.Lower(MI, TmpInst);
247 EmitToStreamer(*OutStreamer, TmpInst);
253 const MCExpr *WebAssemblyAsmPrinter::lowerConstant(const Constant *CV) {
254 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
255 if (GV->getValueType()->isFunctionTy())
256 return MCSymbolRefExpr::create(
257 getSymbol(GV), MCSymbolRefExpr::VK_WebAssembly_FUNCTION, OutContext);
258 return AsmPrinter::lowerConstant(CV);
261 bool WebAssemblyAsmPrinter::PrintAsmOperand(const MachineInstr *MI,
262 unsigned OpNo, unsigned AsmVariant,
263 const char *ExtraCode,
266 report_fatal_error("There are no defined alternate asm variants");
268 // First try the generic code, which knows about modifiers like 'c' and 'n'.
269 if (!AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, OS))
273 const MachineOperand &MO = MI->getOperand(OpNo);
274 switch (MO.getType()) {
275 case MachineOperand::MO_Immediate:
278 case MachineOperand::MO_Register:
279 OS << regToString(MO);
281 case MachineOperand::MO_GlobalAddress:
282 getSymbol(MO.getGlobal())->print(OS, MAI);
283 printOffset(MO.getOffset(), OS);
285 case MachineOperand::MO_ExternalSymbol:
286 GetExternalSymbolSymbol(MO.getSymbolName())->print(OS, MAI);
287 printOffset(MO.getOffset(), OS);
289 case MachineOperand::MO_MachineBasicBlock:
290 MO.getMBB()->getSymbol()->print(OS, MAI);
300 bool WebAssemblyAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
303 const char *ExtraCode,
306 report_fatal_error("There are no defined alternate asm variants");
309 // TODO: For now, we just hard-code 0 as the constant offset; teach
310 // SelectInlineAsmMemoryOperand how to do address mode matching.
311 OS << "0(" + regToString(MI->getOperand(OpNo)) + ')';
315 return AsmPrinter::PrintAsmMemoryOperand(MI, OpNo, AsmVariant, ExtraCode, OS);
318 // Force static initialization.
319 extern "C" void LLVMInitializeWebAssemblyAsmPrinter() {
320 RegisterAsmPrinter<WebAssemblyAsmPrinter> X(getTheWebAssemblyTarget32());
321 RegisterAsmPrinter<WebAssemblyAsmPrinter> Y(getTheWebAssemblyTarget64());