1 //=- WebAssemblyInstPrinter.cpp - WebAssembly assembly instruction printing -=// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 /// 9 /// \file 10 /// Print MCInst instructions to wasm format. 11 /// 12 //===----------------------------------------------------------------------===// 13 14 #include "MCTargetDesc/WebAssemblyInstPrinter.h" 15 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h" 16 #include "WebAssembly.h" 17 #include "WebAssemblyMachineFunctionInfo.h" 18 #include "WebAssemblyUtilities.h" 19 #include "llvm/ADT/SmallSet.h" 20 #include "llvm/ADT/StringExtras.h" 21 #include "llvm/CodeGen/TargetRegisterInfo.h" 22 #include "llvm/MC/MCExpr.h" 23 #include "llvm/MC/MCInst.h" 24 #include "llvm/MC/MCInstrInfo.h" 25 #include "llvm/MC/MCSubtargetInfo.h" 26 #include "llvm/MC/MCSymbol.h" 27 #include "llvm/Support/ErrorHandling.h" 28 #include "llvm/Support/FormattedStream.h" 29 using namespace llvm; 30 31 #define DEBUG_TYPE "asm-printer" 32 33 #include "WebAssemblyGenAsmWriter.inc" 34 35 WebAssemblyInstPrinter::WebAssemblyInstPrinter(const MCAsmInfo &MAI, 36 const MCInstrInfo &MII, 37 const MCRegisterInfo &MRI) 38 : MCInstPrinter(MAI, MII, MRI) {} 39 40 void WebAssemblyInstPrinter::printRegName(raw_ostream &OS, 41 unsigned RegNo) const { 42 assert(RegNo != WebAssemblyFunctionInfo::UnusedReg); 43 // Note that there's an implicit local.get/local.set here! 44 OS << "$" << RegNo; 45 } 46 47 void WebAssemblyInstPrinter::printInst(const MCInst *MI, uint64_t Address, 48 StringRef Annot, 49 const MCSubtargetInfo &STI, 50 raw_ostream &OS) { 51 // Print the instruction (this uses the AsmStrings from the .td files). 52 printInstruction(MI, Address, OS); 53 54 // Print any additional variadic operands. 55 const MCInstrDesc &Desc = MII.get(MI->getOpcode()); 56 if (Desc.isVariadic()) { 57 if ((Desc.getNumOperands() == 0 && MI->getNumOperands() > 0) || 58 Desc.variadicOpsAreDefs()) 59 OS << "\t"; 60 unsigned Start = Desc.getNumOperands(); 61 unsigned NumVariadicDefs = 0; 62 if (Desc.variadicOpsAreDefs()) { 63 // The number of variadic defs is encoded in an immediate by MCInstLower 64 NumVariadicDefs = MI->getOperand(0).getImm(); 65 Start = 1; 66 } 67 bool NeedsComma = Desc.getNumOperands() > 0 && !Desc.variadicOpsAreDefs(); 68 for (auto I = Start, E = MI->getNumOperands(); I < E; ++I) { 69 if (MI->getOpcode() == WebAssembly::CALL_INDIRECT && 70 I - Start == NumVariadicDefs) { 71 // Skip type and flags arguments when printing for tests 72 ++I; 73 continue; 74 } 75 if (NeedsComma) 76 OS << ", "; 77 printOperand(MI, I, OS, I - Start < NumVariadicDefs); 78 NeedsComma = true; 79 } 80 } 81 82 // Print any added annotation. 83 printAnnotation(OS, Annot); 84 85 if (CommentStream) { 86 // Observe any effects on the control flow stack, for use in annotating 87 // control flow label references. 88 unsigned Opc = MI->getOpcode(); 89 switch (Opc) { 90 default: 91 break; 92 93 case WebAssembly::LOOP: 94 case WebAssembly::LOOP_S: 95 printAnnotation(OS, "label" + utostr(ControlFlowCounter) + ':'); 96 ControlFlowStack.push_back(std::make_pair(ControlFlowCounter++, true)); 97 return; 98 99 case WebAssembly::BLOCK: 100 case WebAssembly::BLOCK_S: 101 ControlFlowStack.push_back(std::make_pair(ControlFlowCounter++, false)); 102 return; 103 104 case WebAssembly::TRY: 105 case WebAssembly::TRY_S: 106 ControlFlowStack.push_back(std::make_pair(ControlFlowCounter, false)); 107 TryStack.push_back(ControlFlowCounter++); 108 EHInstStack.push_back(TRY); 109 return; 110 111 case WebAssembly::END_LOOP: 112 case WebAssembly::END_LOOP_S: 113 if (ControlFlowStack.empty()) { 114 printAnnotation(OS, "End marker mismatch!"); 115 } else { 116 ControlFlowStack.pop_back(); 117 } 118 return; 119 120 case WebAssembly::END_BLOCK: 121 case WebAssembly::END_BLOCK_S: 122 if (ControlFlowStack.empty()) { 123 printAnnotation(OS, "End marker mismatch!"); 124 } else { 125 printAnnotation( 126 OS, "label" + utostr(ControlFlowStack.pop_back_val().first) + ':'); 127 } 128 return; 129 130 case WebAssembly::END_TRY: 131 case WebAssembly::END_TRY_S: 132 if (ControlFlowStack.empty() || EHInstStack.empty()) { 133 printAnnotation(OS, "End marker mismatch!"); 134 } else { 135 printAnnotation( 136 OS, "label" + utostr(ControlFlowStack.pop_back_val().first) + ':'); 137 EHInstStack.pop_back(); 138 } 139 return; 140 141 case WebAssembly::CATCH: 142 case WebAssembly::CATCH_S: 143 case WebAssembly::CATCH_ALL: 144 case WebAssembly::CATCH_ALL_S: 145 // There can be multiple catch instructions for one try instruction, so 146 // we print a label only for the first 'catch' label. 147 if (EHInstStack.empty()) { 148 printAnnotation(OS, "try-catch mismatch!"); 149 } else if (EHInstStack.back() == CATCH_ALL) { 150 printAnnotation(OS, "catch/catch_all cannot occur after catch_all"); 151 } else if (EHInstStack.back() == TRY) { 152 if (TryStack.empty()) { 153 printAnnotation(OS, "try-catch mismatch!"); 154 } else { 155 printAnnotation(OS, "catch" + utostr(TryStack.pop_back_val()) + ':'); 156 } 157 EHInstStack.pop_back(); 158 if (Opc == WebAssembly::CATCH || Opc == WebAssembly::CATCH_S) { 159 EHInstStack.push_back(CATCH); 160 } else { 161 EHInstStack.push_back(CATCH_ALL); 162 } 163 } 164 return; 165 166 case WebAssembly::RETHROW: 167 case WebAssembly::RETHROW_S: 168 // 'rethrow' rethrows to the nearest enclosing catch scope, if any. If 169 // there's no enclosing catch scope, it throws up to the caller. 170 if (TryStack.empty()) { 171 printAnnotation(OS, "to caller"); 172 } else { 173 printAnnotation(OS, "down to catch" + utostr(TryStack.back())); 174 } 175 return; 176 177 case WebAssembly::DELEGATE: 178 case WebAssembly::DELEGATE_S: 179 if (ControlFlowStack.empty() || TryStack.empty() || EHInstStack.empty()) { 180 printAnnotation(OS, "try-delegate mismatch!"); 181 } else { 182 // 'delegate' is 183 // 1. A marker for the end of block label 184 // 2. A destination for throwing instructions 185 // 3. An instruction that itself rethrows to another 'catch' 186 assert(ControlFlowStack.back().first == TryStack.back()); 187 std::string Label = "label/catch" + 188 utostr(ControlFlowStack.pop_back_val().first) + 189 ": "; 190 TryStack.pop_back(); 191 EHInstStack.pop_back(); 192 uint64_t Depth = MI->getOperand(0).getImm(); 193 if (Depth >= ControlFlowStack.size()) { 194 Label += "to caller"; 195 } else { 196 const auto &Pair = ControlFlowStack.rbegin()[Depth]; 197 if (Pair.second) 198 printAnnotation(OS, "delegate cannot target a loop"); 199 else 200 Label += "down to catch" + utostr(Pair.first); 201 } 202 printAnnotation(OS, Label); 203 } 204 return; 205 } 206 207 // Annotate any control flow label references. 208 209 unsigned NumFixedOperands = Desc.NumOperands; 210 SmallSet<uint64_t, 8> Printed; 211 for (unsigned I = 0, E = MI->getNumOperands(); I < E; ++I) { 212 // See if this operand denotes a basic block target. 213 if (I < NumFixedOperands) { 214 // A non-variable_ops operand, check its type. 215 if (Desc.OpInfo[I].OperandType != WebAssembly::OPERAND_BASIC_BLOCK) 216 continue; 217 } else { 218 // A variable_ops operand, which currently can be immediates (used in 219 // br_table) which are basic block targets, or for call instructions 220 // when using -wasm-keep-registers (in which case they are registers, 221 // and should not be processed). 222 if (!MI->getOperand(I).isImm()) 223 continue; 224 } 225 uint64_t Depth = MI->getOperand(I).getImm(); 226 if (!Printed.insert(Depth).second) 227 continue; 228 if (Depth >= ControlFlowStack.size()) { 229 printAnnotation(OS, "Invalid depth argument!"); 230 } else { 231 const auto &Pair = ControlFlowStack.rbegin()[Depth]; 232 printAnnotation(OS, utostr(Depth) + ": " + 233 (Pair.second ? "up" : "down") + " to label" + 234 utostr(Pair.first)); 235 } 236 } 237 } 238 } 239 240 static std::string toString(const APFloat &FP) { 241 // Print NaNs with custom payloads specially. 242 if (FP.isNaN() && !FP.bitwiseIsEqual(APFloat::getQNaN(FP.getSemantics())) && 243 !FP.bitwiseIsEqual( 244 APFloat::getQNaN(FP.getSemantics(), /*Negative=*/true))) { 245 APInt AI = FP.bitcastToAPInt(); 246 return std::string(AI.isNegative() ? "-" : "") + "nan:0x" + 247 utohexstr(AI.getZExtValue() & 248 (AI.getBitWidth() == 32 ? INT64_C(0x007fffff) 249 : INT64_C(0x000fffffffffffff)), 250 /*LowerCase=*/true); 251 } 252 253 // Use C99's hexadecimal floating-point representation. 254 static const size_t BufBytes = 128; 255 char Buf[BufBytes]; 256 auto Written = FP.convertToHexString( 257 Buf, /*HexDigits=*/0, /*UpperCase=*/false, APFloat::rmNearestTiesToEven); 258 (void)Written; 259 assert(Written != 0); 260 assert(Written < BufBytes); 261 return Buf; 262 } 263 264 void WebAssemblyInstPrinter::printOperand(const MCInst *MI, unsigned OpNo, 265 raw_ostream &O, bool IsVariadicDef) { 266 const MCOperand &Op = MI->getOperand(OpNo); 267 if (Op.isReg()) { 268 const MCInstrDesc &Desc = MII.get(MI->getOpcode()); 269 unsigned WAReg = Op.getReg(); 270 if (int(WAReg) >= 0) 271 printRegName(O, WAReg); 272 else if (OpNo >= Desc.getNumDefs() && !IsVariadicDef) 273 O << "$pop" << WebAssemblyFunctionInfo::getWARegStackId(WAReg); 274 else if (WAReg != WebAssemblyFunctionInfo::UnusedReg) 275 O << "$push" << WebAssemblyFunctionInfo::getWARegStackId(WAReg); 276 else 277 O << "$drop"; 278 // Add a '=' suffix if this is a def. 279 if (OpNo < MII.get(MI->getOpcode()).getNumDefs() || IsVariadicDef) 280 O << '='; 281 } else if (Op.isImm()) { 282 O << Op.getImm(); 283 } else if (Op.isSFPImm()) { 284 O << ::toString(APFloat(bit_cast<float>(Op.getSFPImm()))); 285 } else if (Op.isDFPImm()) { 286 O << ::toString(APFloat(bit_cast<double>(Op.getDFPImm()))); 287 } else { 288 assert(Op.isExpr() && "unknown operand kind in printOperand"); 289 // call_indirect instructions have a TYPEINDEX operand that we print 290 // as a signature here, such that the assembler can recover this 291 // information. 292 auto SRE = static_cast<const MCSymbolRefExpr *>(Op.getExpr()); 293 if (SRE->getKind() == MCSymbolRefExpr::VK_WASM_TYPEINDEX) { 294 auto &Sym = static_cast<const MCSymbolWasm &>(SRE->getSymbol()); 295 O << WebAssembly::signatureToString(Sym.getSignature()); 296 } else { 297 Op.getExpr()->print(O, &MAI); 298 } 299 } 300 } 301 302 void WebAssemblyInstPrinter::printBrList(const MCInst *MI, unsigned OpNo, 303 raw_ostream &O) { 304 O << "{"; 305 for (unsigned I = OpNo, E = MI->getNumOperands(); I != E; ++I) { 306 if (I != OpNo) 307 O << ", "; 308 O << MI->getOperand(I).getImm(); 309 } 310 O << "}"; 311 } 312 313 void WebAssemblyInstPrinter::printWebAssemblyP2AlignOperand(const MCInst *MI, 314 unsigned OpNo, 315 raw_ostream &O) { 316 int64_t Imm = MI->getOperand(OpNo).getImm(); 317 if (Imm == WebAssembly::GetDefaultP2Align(MI->getOpcode())) 318 return; 319 O << ":p2align=" << Imm; 320 } 321 322 void WebAssemblyInstPrinter::printWebAssemblySignatureOperand(const MCInst *MI, 323 unsigned OpNo, 324 raw_ostream &O) { 325 const MCOperand &Op = MI->getOperand(OpNo); 326 if (Op.isImm()) { 327 auto Imm = static_cast<unsigned>(Op.getImm()); 328 if (Imm != wasm::WASM_TYPE_NORESULT) 329 O << WebAssembly::anyTypeToString(Imm); 330 } else { 331 auto Expr = cast<MCSymbolRefExpr>(Op.getExpr()); 332 auto *Sym = cast<MCSymbolWasm>(&Expr->getSymbol()); 333 if (Sym->getSignature()) { 334 O << WebAssembly::signatureToString(Sym->getSignature()); 335 } else { 336 // Disassembler does not currently produce a signature 337 O << "unknown_type"; 338 } 339 } 340 } 341 342 void WebAssemblyInstPrinter::printWebAssemblyHeapTypeOperand(const MCInst *MI, 343 unsigned OpNo, 344 raw_ostream &O) { 345 const MCOperand &Op = MI->getOperand(OpNo); 346 if (Op.isImm()) { 347 switch (Op.getImm()) { 348 case long(wasm::ValType::EXTERNREF): 349 O << "extern"; 350 break; 351 case long(wasm::ValType::FUNCREF): 352 O << "func"; 353 break; 354 default: 355 O << "unsupported_heap_type_value"; 356 break; 357 } 358 } else { 359 // Typed function references and other subtypes of funcref and externref 360 // currently unimplemented. 361 O << "unsupported_heap_type_operand"; 362 } 363 } 364 365 // We have various enums representing a subset of these types, use this 366 // function to convert any of them to text. 367 const char *WebAssembly::anyTypeToString(unsigned Ty) { 368 switch (Ty) { 369 case wasm::WASM_TYPE_I32: 370 return "i32"; 371 case wasm::WASM_TYPE_I64: 372 return "i64"; 373 case wasm::WASM_TYPE_F32: 374 return "f32"; 375 case wasm::WASM_TYPE_F64: 376 return "f64"; 377 case wasm::WASM_TYPE_V128: 378 return "v128"; 379 case wasm::WASM_TYPE_FUNCREF: 380 return "funcref"; 381 case wasm::WASM_TYPE_EXTERNREF: 382 return "externref"; 383 case wasm::WASM_TYPE_FUNC: 384 return "func"; 385 case wasm::WASM_TYPE_NORESULT: 386 return "void"; 387 default: 388 return "invalid_type"; 389 } 390 } 391 392 const char *WebAssembly::typeToString(wasm::ValType Ty) { 393 return anyTypeToString(static_cast<unsigned>(Ty)); 394 } 395 396 std::string WebAssembly::typeListToString(ArrayRef<wasm::ValType> List) { 397 std::string S; 398 for (auto &Ty : List) { 399 if (&Ty != &List[0]) S += ", "; 400 S += WebAssembly::typeToString(Ty); 401 } 402 return S; 403 } 404 405 std::string WebAssembly::signatureToString(const wasm::WasmSignature *Sig) { 406 std::string S("("); 407 S += typeListToString(Sig->Params); 408 S += ") -> ("; 409 S += typeListToString(Sig->Returns); 410 S += ")"; 411 return S; 412 } 413