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 DelegateStack.push_back(ControlFlowCounter++); 98 return; 99 100 case WebAssembly::BLOCK: 101 case WebAssembly::BLOCK_S: 102 ControlFlowStack.push_back(std::make_pair(ControlFlowCounter, false)); 103 DelegateStack.push_back(ControlFlowCounter++); 104 return; 105 106 case WebAssembly::TRY: 107 case WebAssembly::TRY_S: 108 ControlFlowStack.push_back(std::make_pair(ControlFlowCounter, false)); 109 EHPadStack.push_back(ControlFlowCounter); 110 DelegateStack.push_back(ControlFlowCounter++); 111 EHInstStack.push_back(TRY); 112 return; 113 114 case WebAssembly::END_LOOP: 115 case WebAssembly::END_LOOP_S: 116 if (ControlFlowStack.empty() || DelegateStack.empty()) { 117 printAnnotation(OS, "End marker mismatch!"); 118 } else { 119 ControlFlowStack.pop_back(); 120 DelegateStack.pop_back(); 121 } 122 return; 123 124 case WebAssembly::END_BLOCK: 125 case WebAssembly::END_BLOCK_S: 126 if (ControlFlowStack.empty() || DelegateStack.empty()) { 127 printAnnotation(OS, "End marker mismatch!"); 128 } else { 129 printAnnotation( 130 OS, "label" + utostr(ControlFlowStack.pop_back_val().first) + ':'); 131 DelegateStack.pop_back(); 132 } 133 return; 134 135 case WebAssembly::END_TRY: 136 case WebAssembly::END_TRY_S: 137 if (ControlFlowStack.empty() || EHInstStack.empty()) { 138 printAnnotation(OS, "End marker mismatch!"); 139 } else { 140 printAnnotation( 141 OS, "label" + utostr(ControlFlowStack.pop_back_val().first) + ':'); 142 EHInstStack.pop_back(); 143 } 144 return; 145 146 case WebAssembly::CATCH: 147 case WebAssembly::CATCH_S: 148 case WebAssembly::CATCH_ALL: 149 case WebAssembly::CATCH_ALL_S: 150 // There can be multiple catch instructions for one try instruction, so 151 // we print a label only for the first 'catch' label. 152 if (EHInstStack.empty()) { 153 printAnnotation(OS, "try-catch mismatch!"); 154 } else if (EHInstStack.back() == CATCH_ALL) { 155 printAnnotation(OS, "catch/catch_all cannot occur after catch_all"); 156 } else if (EHInstStack.back() == TRY) { 157 if (EHPadStack.empty() || DelegateStack.empty()) { 158 printAnnotation(OS, "try-catch mismatch!"); 159 } else { 160 printAnnotation(OS, 161 "catch" + utostr(EHPadStack.pop_back_val()) + ':'); 162 DelegateStack.pop_back(); 163 } 164 EHInstStack.pop_back(); 165 if (Opc == WebAssembly::CATCH || Opc == WebAssembly::CATCH_S) { 166 EHInstStack.push_back(CATCH); 167 } else { 168 EHInstStack.push_back(CATCH_ALL); 169 } 170 } 171 return; 172 173 case WebAssembly::RETHROW: 174 case WebAssembly::RETHROW_S: 175 // 'rethrow' rethrows to the nearest enclosing catch scope, if any. If 176 // there's no enclosing catch scope, it throws up to the caller. 177 if (EHPadStack.empty()) { 178 printAnnotation(OS, "to caller"); 179 } else { 180 printAnnotation(OS, "down to catch" + utostr(EHPadStack.back())); 181 } 182 return; 183 184 case WebAssembly::DELEGATE: 185 case WebAssembly::DELEGATE_S: 186 if (ControlFlowStack.empty() || EHPadStack.empty() || 187 DelegateStack.empty() || EHInstStack.empty()) { 188 printAnnotation(OS, "try-delegate mismatch!"); 189 } else { 190 // 'delegate' is 191 // 1. A marker for the end of block label 192 // 2. A destination for throwing instructions 193 // 3. An instruction that itself rethrows to another 'catch' 194 assert(ControlFlowStack.back().first == EHPadStack.back() && 195 EHPadStack.back() == DelegateStack.back()); 196 std::string Label = "label/catch" + 197 utostr(ControlFlowStack.pop_back_val().first) + 198 ": "; 199 EHPadStack.pop_back(); 200 DelegateStack.pop_back(); 201 EHInstStack.pop_back(); 202 uint64_t Depth = MI->getOperand(0).getImm(); 203 if (Depth >= DelegateStack.size()) { 204 Label += "to caller"; 205 } else { 206 Label += "down to catch" + utostr(DelegateStack.rbegin()[Depth]); 207 } 208 printAnnotation(OS, Label); 209 } 210 return; 211 } 212 213 // Annotate any control flow label references. 214 215 unsigned NumFixedOperands = Desc.NumOperands; 216 SmallSet<uint64_t, 8> Printed; 217 for (unsigned I = 0, E = MI->getNumOperands(); I < E; ++I) { 218 // See if this operand denotes a basic block target. 219 if (I < NumFixedOperands) { 220 // A non-variable_ops operand, check its type. 221 if (Desc.OpInfo[I].OperandType != WebAssembly::OPERAND_BASIC_BLOCK) 222 continue; 223 } else { 224 // A variable_ops operand, which currently can be immediates (used in 225 // br_table) which are basic block targets, or for call instructions 226 // when using -wasm-keep-registers (in which case they are registers, 227 // and should not be processed). 228 if (!MI->getOperand(I).isImm()) 229 continue; 230 } 231 uint64_t Depth = MI->getOperand(I).getImm(); 232 if (!Printed.insert(Depth).second) 233 continue; 234 if (Depth >= ControlFlowStack.size()) { 235 printAnnotation(OS, "Invalid depth argument!"); 236 } else { 237 const auto &Pair = ControlFlowStack.rbegin()[Depth]; 238 printAnnotation(OS, utostr(Depth) + ": " + 239 (Pair.second ? "up" : "down") + " to label" + 240 utostr(Pair.first)); 241 } 242 } 243 } 244 } 245 246 static std::string toString(const APFloat &FP) { 247 // Print NaNs with custom payloads specially. 248 if (FP.isNaN() && !FP.bitwiseIsEqual(APFloat::getQNaN(FP.getSemantics())) && 249 !FP.bitwiseIsEqual( 250 APFloat::getQNaN(FP.getSemantics(), /*Negative=*/true))) { 251 APInt AI = FP.bitcastToAPInt(); 252 return std::string(AI.isNegative() ? "-" : "") + "nan:0x" + 253 utohexstr(AI.getZExtValue() & 254 (AI.getBitWidth() == 32 ? INT64_C(0x007fffff) 255 : INT64_C(0x000fffffffffffff)), 256 /*LowerCase=*/true); 257 } 258 259 // Use C99's hexadecimal floating-point representation. 260 static const size_t BufBytes = 128; 261 char Buf[BufBytes]; 262 auto Written = FP.convertToHexString( 263 Buf, /*HexDigits=*/0, /*UpperCase=*/false, APFloat::rmNearestTiesToEven); 264 (void)Written; 265 assert(Written != 0); 266 assert(Written < BufBytes); 267 return Buf; 268 } 269 270 void WebAssemblyInstPrinter::printOperand(const MCInst *MI, unsigned OpNo, 271 raw_ostream &O, bool IsVariadicDef) { 272 const MCOperand &Op = MI->getOperand(OpNo); 273 if (Op.isReg()) { 274 const MCInstrDesc &Desc = MII.get(MI->getOpcode()); 275 unsigned WAReg = Op.getReg(); 276 if (int(WAReg) >= 0) 277 printRegName(O, WAReg); 278 else if (OpNo >= Desc.getNumDefs() && !IsVariadicDef) 279 O << "$pop" << WebAssemblyFunctionInfo::getWARegStackId(WAReg); 280 else if (WAReg != WebAssemblyFunctionInfo::UnusedReg) 281 O << "$push" << WebAssemblyFunctionInfo::getWARegStackId(WAReg); 282 else 283 O << "$drop"; 284 // Add a '=' suffix if this is a def. 285 if (OpNo < MII.get(MI->getOpcode()).getNumDefs() || IsVariadicDef) 286 O << '='; 287 } else if (Op.isImm()) { 288 O << Op.getImm(); 289 } else if (Op.isSFPImm()) { 290 O << ::toString(APFloat(bit_cast<float>(Op.getSFPImm()))); 291 } else if (Op.isDFPImm()) { 292 O << ::toString(APFloat(bit_cast<double>(Op.getDFPImm()))); 293 } else { 294 assert(Op.isExpr() && "unknown operand kind in printOperand"); 295 // call_indirect instructions have a TYPEINDEX operand that we print 296 // as a signature here, such that the assembler can recover this 297 // information. 298 auto SRE = static_cast<const MCSymbolRefExpr *>(Op.getExpr()); 299 if (SRE->getKind() == MCSymbolRefExpr::VK_WASM_TYPEINDEX) { 300 auto &Sym = static_cast<const MCSymbolWasm &>(SRE->getSymbol()); 301 O << WebAssembly::signatureToString(Sym.getSignature()); 302 } else { 303 Op.getExpr()->print(O, &MAI); 304 } 305 } 306 } 307 308 void WebAssemblyInstPrinter::printBrList(const MCInst *MI, unsigned OpNo, 309 raw_ostream &O) { 310 O << "{"; 311 for (unsigned I = OpNo, E = MI->getNumOperands(); I != E; ++I) { 312 if (I != OpNo) 313 O << ", "; 314 O << MI->getOperand(I).getImm(); 315 } 316 O << "}"; 317 } 318 319 void WebAssemblyInstPrinter::printWebAssemblyP2AlignOperand(const MCInst *MI, 320 unsigned OpNo, 321 raw_ostream &O) { 322 int64_t Imm = MI->getOperand(OpNo).getImm(); 323 if (Imm == WebAssembly::GetDefaultP2Align(MI->getOpcode())) 324 return; 325 O << ":p2align=" << Imm; 326 } 327 328 void WebAssemblyInstPrinter::printWebAssemblySignatureOperand(const MCInst *MI, 329 unsigned OpNo, 330 raw_ostream &O) { 331 const MCOperand &Op = MI->getOperand(OpNo); 332 if (Op.isImm()) { 333 auto Imm = static_cast<unsigned>(Op.getImm()); 334 if (Imm != wasm::WASM_TYPE_NORESULT) 335 O << WebAssembly::anyTypeToString(Imm); 336 } else { 337 auto Expr = cast<MCSymbolRefExpr>(Op.getExpr()); 338 auto *Sym = cast<MCSymbolWasm>(&Expr->getSymbol()); 339 if (Sym->getSignature()) { 340 O << WebAssembly::signatureToString(Sym->getSignature()); 341 } else { 342 // Disassembler does not currently produce a signature 343 O << "unknown_type"; 344 } 345 } 346 } 347 348 void WebAssemblyInstPrinter::printWebAssemblyHeapTypeOperand(const MCInst *MI, 349 unsigned OpNo, 350 raw_ostream &O) { 351 const MCOperand &Op = MI->getOperand(OpNo); 352 if (Op.isImm()) { 353 switch (Op.getImm()) { 354 case long(wasm::ValType::EXTERNREF): 355 O << "extern"; 356 break; 357 case long(wasm::ValType::FUNCREF): 358 O << "func"; 359 break; 360 default: 361 O << "unsupported_heap_type_value"; 362 break; 363 } 364 } else { 365 // Typed function references and other subtypes of funcref and externref 366 // currently unimplemented. 367 O << "unsupported_heap_type_operand"; 368 } 369 } 370 371 // We have various enums representing a subset of these types, use this 372 // function to convert any of them to text. 373 const char *WebAssembly::anyTypeToString(unsigned Ty) { 374 switch (Ty) { 375 case wasm::WASM_TYPE_I32: 376 return "i32"; 377 case wasm::WASM_TYPE_I64: 378 return "i64"; 379 case wasm::WASM_TYPE_F32: 380 return "f32"; 381 case wasm::WASM_TYPE_F64: 382 return "f64"; 383 case wasm::WASM_TYPE_V128: 384 return "v128"; 385 case wasm::WASM_TYPE_FUNCREF: 386 return "funcref"; 387 case wasm::WASM_TYPE_EXTERNREF: 388 return "externref"; 389 case wasm::WASM_TYPE_FUNC: 390 return "func"; 391 case wasm::WASM_TYPE_NORESULT: 392 return "void"; 393 default: 394 return "invalid_type"; 395 } 396 } 397 398 const char *WebAssembly::typeToString(wasm::ValType Ty) { 399 return anyTypeToString(static_cast<unsigned>(Ty)); 400 } 401 402 std::string WebAssembly::typeListToString(ArrayRef<wasm::ValType> List) { 403 std::string S; 404 for (auto &Ty : List) { 405 if (&Ty != &List[0]) S += ", "; 406 S += WebAssembly::typeToString(Ty); 407 } 408 return S; 409 } 410 411 std::string WebAssembly::signatureToString(const wasm::WasmSignature *Sig) { 412 std::string S("("); 413 S += typeListToString(Sig->Params); 414 S += ") -> ("; 415 S += typeListToString(Sig->Returns); 416 S += ")"; 417 return S; 418 } 419