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 "Utils/WebAssemblyTypeUtilities.h" 17 #include "Utils/WebAssemblyUtilities.h" 18 #include "WebAssembly.h" 19 #include "WebAssemblyMachineFunctionInfo.h" 20 #include "llvm/ADT/SmallSet.h" 21 #include "llvm/ADT/StringExtras.h" 22 #include "llvm/CodeGen/TargetRegisterInfo.h" 23 #include "llvm/MC/MCExpr.h" 24 #include "llvm/MC/MCInst.h" 25 #include "llvm/MC/MCInstrInfo.h" 26 #include "llvm/MC/MCSubtargetInfo.h" 27 #include "llvm/MC/MCSymbol.h" 28 #include "llvm/Support/ErrorHandling.h" 29 #include "llvm/Support/FormattedStream.h" 30 using namespace llvm; 31 32 #define DEBUG_TYPE "asm-printer" 33 34 #include "WebAssemblyGenAsmWriter.inc" 35 36 WebAssemblyInstPrinter::WebAssemblyInstPrinter(const MCAsmInfo &MAI, 37 const MCInstrInfo &MII, 38 const MCRegisterInfo &MRI) 39 : MCInstPrinter(MAI, MII, MRI) {} 40 41 void WebAssemblyInstPrinter::printRegName(raw_ostream &OS, 42 unsigned RegNo) const { 43 assert(RegNo != WebAssemblyFunctionInfo::UnusedReg); 44 // Note that there's an implicit local.get/local.set here! 45 OS << "$" << RegNo; 46 } 47 48 void WebAssemblyInstPrinter::printInst(const MCInst *MI, uint64_t Address, 49 StringRef Annot, 50 const MCSubtargetInfo &STI, 51 raw_ostream &OS) { 52 switch (MI->getOpcode()) { 53 case WebAssembly::CALL_INDIRECT_S: 54 case WebAssembly::RET_CALL_INDIRECT_S: { 55 // A special case for call_indirect (and ret_call_indirect), if the table 56 // operand is a symbol: the order of the type and table operands is inverted 57 // in the text format relative to the binary format. Otherwise if table the 58 // operand isn't a symbol, then we have an MVP compilation unit, and the 59 // table shouldn't appear in the output. 60 OS << "\t"; 61 OS << getMnemonic(MI).first; 62 OS << " "; 63 64 assert(MI->getNumOperands() == 2); 65 const unsigned TypeOperand = 0; 66 const unsigned TableOperand = 1; 67 if (MI->getOperand(TableOperand).isExpr()) { 68 printOperand(MI, TableOperand, OS); 69 OS << ", "; 70 } else { 71 assert(MI->getOperand(TableOperand).getImm() == 0); 72 } 73 printOperand(MI, TypeOperand, OS); 74 break; 75 } 76 default: 77 // Print the instruction (this uses the AsmStrings from the .td files). 78 printInstruction(MI, Address, OS); 79 break; 80 } 81 82 // Print any additional variadic operands. 83 const MCInstrDesc &Desc = MII.get(MI->getOpcode()); 84 if (Desc.isVariadic()) { 85 if ((Desc.getNumOperands() == 0 && MI->getNumOperands() > 0) || 86 Desc.variadicOpsAreDefs()) 87 OS << "\t"; 88 unsigned Start = Desc.getNumOperands(); 89 unsigned NumVariadicDefs = 0; 90 if (Desc.variadicOpsAreDefs()) { 91 // The number of variadic defs is encoded in an immediate by MCInstLower 92 NumVariadicDefs = MI->getOperand(0).getImm(); 93 Start = 1; 94 } 95 bool NeedsComma = Desc.getNumOperands() > 0 && !Desc.variadicOpsAreDefs(); 96 for (auto I = Start, E = MI->getNumOperands(); I < E; ++I) { 97 if (MI->getOpcode() == WebAssembly::CALL_INDIRECT && 98 I - Start == NumVariadicDefs) { 99 // Skip type and table arguments when printing for tests. 100 ++I; 101 continue; 102 } 103 if (NeedsComma) 104 OS << ", "; 105 printOperand(MI, I, OS, I - Start < NumVariadicDefs); 106 NeedsComma = true; 107 } 108 } 109 110 // Print any added annotation. 111 printAnnotation(OS, Annot); 112 113 if (CommentStream) { 114 // Observe any effects on the control flow stack, for use in annotating 115 // control flow label references. 116 unsigned Opc = MI->getOpcode(); 117 switch (Opc) { 118 default: 119 break; 120 121 case WebAssembly::LOOP: 122 case WebAssembly::LOOP_S: 123 printAnnotation(OS, "label" + utostr(ControlFlowCounter) + ':'); 124 ControlFlowStack.push_back(std::make_pair(ControlFlowCounter++, true)); 125 return; 126 127 case WebAssembly::BLOCK: 128 case WebAssembly::BLOCK_S: 129 ControlFlowStack.push_back(std::make_pair(ControlFlowCounter++, false)); 130 return; 131 132 case WebAssembly::TRY: 133 case WebAssembly::TRY_S: 134 ControlFlowStack.push_back(std::make_pair(ControlFlowCounter, false)); 135 TryStack.push_back(ControlFlowCounter++); 136 EHInstStack.push_back(TRY); 137 return; 138 139 case WebAssembly::END_LOOP: 140 case WebAssembly::END_LOOP_S: 141 if (ControlFlowStack.empty()) { 142 printAnnotation(OS, "End marker mismatch!"); 143 } else { 144 ControlFlowStack.pop_back(); 145 } 146 return; 147 148 case WebAssembly::END_BLOCK: 149 case WebAssembly::END_BLOCK_S: 150 if (ControlFlowStack.empty()) { 151 printAnnotation(OS, "End marker mismatch!"); 152 } else { 153 printAnnotation( 154 OS, "label" + utostr(ControlFlowStack.pop_back_val().first) + ':'); 155 } 156 return; 157 158 case WebAssembly::END_TRY: 159 case WebAssembly::END_TRY_S: 160 if (ControlFlowStack.empty() || EHInstStack.empty()) { 161 printAnnotation(OS, "End marker mismatch!"); 162 } else { 163 printAnnotation( 164 OS, "label" + utostr(ControlFlowStack.pop_back_val().first) + ':'); 165 EHInstStack.pop_back(); 166 } 167 return; 168 169 case WebAssembly::CATCH: 170 case WebAssembly::CATCH_S: 171 case WebAssembly::CATCH_ALL: 172 case WebAssembly::CATCH_ALL_S: 173 // There can be multiple catch instructions for one try instruction, so 174 // we print a label only for the first 'catch' label. 175 if (EHInstStack.empty()) { 176 printAnnotation(OS, "try-catch mismatch!"); 177 } else if (EHInstStack.back() == CATCH_ALL) { 178 printAnnotation(OS, "catch/catch_all cannot occur after catch_all"); 179 } else if (EHInstStack.back() == TRY) { 180 if (TryStack.empty()) { 181 printAnnotation(OS, "try-catch mismatch!"); 182 } else { 183 printAnnotation(OS, "catch" + utostr(TryStack.pop_back_val()) + ':'); 184 } 185 EHInstStack.pop_back(); 186 if (Opc == WebAssembly::CATCH || Opc == WebAssembly::CATCH_S) { 187 EHInstStack.push_back(CATCH); 188 } else { 189 EHInstStack.push_back(CATCH_ALL); 190 } 191 } 192 return; 193 194 case WebAssembly::RETHROW: 195 case WebAssembly::RETHROW_S: 196 // 'rethrow' rethrows to the nearest enclosing catch scope, if any. If 197 // there's no enclosing catch scope, it throws up to the caller. 198 if (TryStack.empty()) { 199 printAnnotation(OS, "to caller"); 200 } else { 201 printAnnotation(OS, "down to catch" + utostr(TryStack.back())); 202 } 203 return; 204 205 case WebAssembly::DELEGATE: 206 case WebAssembly::DELEGATE_S: 207 if (ControlFlowStack.empty() || TryStack.empty() || EHInstStack.empty()) { 208 printAnnotation(OS, "try-delegate mismatch!"); 209 } else { 210 // 'delegate' is 211 // 1. A marker for the end of block label 212 // 2. A destination for throwing instructions 213 // 3. An instruction that itself rethrows to another 'catch' 214 assert(ControlFlowStack.back().first == TryStack.back()); 215 std::string Label = "label/catch" + 216 utostr(ControlFlowStack.pop_back_val().first) + 217 ": "; 218 TryStack.pop_back(); 219 EHInstStack.pop_back(); 220 uint64_t Depth = MI->getOperand(0).getImm(); 221 if (Depth >= ControlFlowStack.size()) { 222 Label += "to caller"; 223 } else { 224 const auto &Pair = ControlFlowStack.rbegin()[Depth]; 225 if (Pair.second) 226 printAnnotation(OS, "delegate cannot target a loop"); 227 else 228 Label += "down to catch" + utostr(Pair.first); 229 } 230 printAnnotation(OS, Label); 231 } 232 return; 233 } 234 235 // Annotate any control flow label references. 236 237 unsigned NumFixedOperands = Desc.NumOperands; 238 SmallSet<uint64_t, 8> Printed; 239 for (unsigned I = 0, E = MI->getNumOperands(); I < E; ++I) { 240 // See if this operand denotes a basic block target. 241 if (I < NumFixedOperands) { 242 // A non-variable_ops operand, check its type. 243 if (Desc.OpInfo[I].OperandType != WebAssembly::OPERAND_BASIC_BLOCK) 244 continue; 245 } else { 246 // A variable_ops operand, which currently can be immediates (used in 247 // br_table) which are basic block targets, or for call instructions 248 // when using -wasm-keep-registers (in which case they are registers, 249 // and should not be processed). 250 if (!MI->getOperand(I).isImm()) 251 continue; 252 } 253 uint64_t Depth = MI->getOperand(I).getImm(); 254 if (!Printed.insert(Depth).second) 255 continue; 256 if (Depth >= ControlFlowStack.size()) { 257 printAnnotation(OS, "Invalid depth argument!"); 258 } else { 259 const auto &Pair = ControlFlowStack.rbegin()[Depth]; 260 printAnnotation(OS, utostr(Depth) + ": " + 261 (Pair.second ? "up" : "down") + " to label" + 262 utostr(Pair.first)); 263 } 264 } 265 } 266 } 267 268 static std::string toString(const APFloat &FP) { 269 // Print NaNs with custom payloads specially. 270 if (FP.isNaN() && !FP.bitwiseIsEqual(APFloat::getQNaN(FP.getSemantics())) && 271 !FP.bitwiseIsEqual( 272 APFloat::getQNaN(FP.getSemantics(), /*Negative=*/true))) { 273 APInt AI = FP.bitcastToAPInt(); 274 return std::string(AI.isNegative() ? "-" : "") + "nan:0x" + 275 utohexstr(AI.getZExtValue() & 276 (AI.getBitWidth() == 32 ? INT64_C(0x007fffff) 277 : INT64_C(0x000fffffffffffff)), 278 /*LowerCase=*/true); 279 } 280 281 // Use C99's hexadecimal floating-point representation. 282 static const size_t BufBytes = 128; 283 char Buf[BufBytes]; 284 auto Written = FP.convertToHexString( 285 Buf, /*HexDigits=*/0, /*UpperCase=*/false, APFloat::rmNearestTiesToEven); 286 (void)Written; 287 assert(Written != 0); 288 assert(Written < BufBytes); 289 return Buf; 290 } 291 292 void WebAssemblyInstPrinter::printOperand(const MCInst *MI, unsigned OpNo, 293 raw_ostream &O, bool IsVariadicDef) { 294 const MCOperand &Op = MI->getOperand(OpNo); 295 if (Op.isReg()) { 296 const MCInstrDesc &Desc = MII.get(MI->getOpcode()); 297 unsigned WAReg = Op.getReg(); 298 if (int(WAReg) >= 0) 299 printRegName(O, WAReg); 300 else if (OpNo >= Desc.getNumDefs() && !IsVariadicDef) 301 O << "$pop" << WebAssemblyFunctionInfo::getWARegStackId(WAReg); 302 else if (WAReg != WebAssemblyFunctionInfo::UnusedReg) 303 O << "$push" << WebAssemblyFunctionInfo::getWARegStackId(WAReg); 304 else 305 O << "$drop"; 306 // Add a '=' suffix if this is a def. 307 if (OpNo < MII.get(MI->getOpcode()).getNumDefs() || IsVariadicDef) 308 O << '='; 309 } else if (Op.isImm()) { 310 O << Op.getImm(); 311 } else if (Op.isSFPImm()) { 312 O << ::toString(APFloat(APFloat::IEEEsingle(), APInt(32, Op.getSFPImm()))); 313 } else if (Op.isDFPImm()) { 314 O << ::toString(APFloat(APFloat::IEEEdouble(), APInt(64, Op.getDFPImm()))); 315 } else { 316 assert(Op.isExpr() && "unknown operand kind in printOperand"); 317 // call_indirect instructions have a TYPEINDEX operand that we print 318 // as a signature here, such that the assembler can recover this 319 // information. 320 auto SRE = static_cast<const MCSymbolRefExpr *>(Op.getExpr()); 321 if (SRE->getKind() == MCSymbolRefExpr::VK_WASM_TYPEINDEX) { 322 auto &Sym = static_cast<const MCSymbolWasm &>(SRE->getSymbol()); 323 O << WebAssembly::signatureToString(Sym.getSignature()); 324 } else { 325 Op.getExpr()->print(O, &MAI); 326 } 327 } 328 } 329 330 void WebAssemblyInstPrinter::printBrList(const MCInst *MI, unsigned OpNo, 331 raw_ostream &O) { 332 O << "{"; 333 for (unsigned I = OpNo, E = MI->getNumOperands(); I != E; ++I) { 334 if (I != OpNo) 335 O << ", "; 336 O << MI->getOperand(I).getImm(); 337 } 338 O << "}"; 339 } 340 341 void WebAssemblyInstPrinter::printWebAssemblyP2AlignOperand(const MCInst *MI, 342 unsigned OpNo, 343 raw_ostream &O) { 344 int64_t Imm = MI->getOperand(OpNo).getImm(); 345 if (Imm == WebAssembly::GetDefaultP2Align(MI->getOpcode())) 346 return; 347 O << ":p2align=" << Imm; 348 } 349 350 void WebAssemblyInstPrinter::printWebAssemblySignatureOperand(const MCInst *MI, 351 unsigned OpNo, 352 raw_ostream &O) { 353 const MCOperand &Op = MI->getOperand(OpNo); 354 if (Op.isImm()) { 355 auto Imm = static_cast<unsigned>(Op.getImm()); 356 if (Imm != wasm::WASM_TYPE_NORESULT) 357 O << WebAssembly::anyTypeToString(Imm); 358 } else { 359 auto Expr = cast<MCSymbolRefExpr>(Op.getExpr()); 360 auto *Sym = cast<MCSymbolWasm>(&Expr->getSymbol()); 361 if (Sym->getSignature()) { 362 O << WebAssembly::signatureToString(Sym->getSignature()); 363 } else { 364 // Disassembler does not currently produce a signature 365 O << "unknown_type"; 366 } 367 } 368 } 369 370 void WebAssemblyInstPrinter::printWebAssemblyHeapTypeOperand(const MCInst *MI, 371 unsigned OpNo, 372 raw_ostream &O) { 373 const MCOperand &Op = MI->getOperand(OpNo); 374 if (Op.isImm()) { 375 switch (Op.getImm()) { 376 case long(wasm::ValType::EXTERNREF): 377 O << "extern"; 378 break; 379 case long(wasm::ValType::FUNCREF): 380 O << "func"; 381 break; 382 default: 383 O << "unsupported_heap_type_value"; 384 break; 385 } 386 } else { 387 // Typed function references and other subtypes of funcref and externref 388 // currently unimplemented. 389 O << "unsupported_heap_type_operand"; 390 } 391 } 392
Indexes created Wed Jun 10 00:26:05 UTC 2026