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