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1//===- MILexer.cpp - Machine instructions lexer implementation ------------===//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-exception6//7//===----------------------------------------------------------------------===//8//9// This file implements the lexing of machine instructions.10//11//===----------------------------------------------------------------------===//12 13#include "MILexer.h"14#include "llvm/ADT/StringExtras.h"15#include "llvm/ADT/StringSwitch.h"16#include "llvm/ADT/Twine.h"17#include <cassert>18#include <cctype>19#include <string>20 21using namespace llvm;22 23namespace {24 25using ErrorCallbackType =26    function_ref<void(StringRef::iterator Loc, const Twine &)>;27 28/// This class provides a way to iterate and get characters from the source29/// string.30class Cursor {31  const char *Ptr = nullptr;32  const char *End = nullptr;33 34public:35  Cursor(std::nullopt_t) {}36 37  explicit Cursor(StringRef Str) {38    Ptr = Str.data();39    End = Ptr + Str.size();40  }41 42  bool isEOF() const { return Ptr == End; }43 44  char peek(int I = 0) const { return End - Ptr <= I ? 0 : Ptr[I]; }45 46  void advance(unsigned I = 1) { Ptr += I; }47 48  StringRef remaining() const { return StringRef(Ptr, End - Ptr); }49 50  StringRef upto(Cursor C) const {51    assert(C.Ptr >= Ptr && C.Ptr <= End);52    return StringRef(Ptr, C.Ptr - Ptr);53  }54 55  StringRef::iterator location() const { return Ptr; }56 57  operator bool() const { return Ptr != nullptr; }58};59 60} // end anonymous namespace61 62MIToken &MIToken::reset(TokenKind Kind, StringRef Range) {63  this->Kind = Kind;64  this->Range = Range;65  return *this;66}67 68MIToken &MIToken::setStringValue(StringRef StrVal) {69  StringValue = StrVal;70  return *this;71}72 73MIToken &MIToken::setOwnedStringValue(std::string StrVal) {74  StringValueStorage = std::move(StrVal);75  StringValue = StringValueStorage;76  return *this;77}78 79MIToken &MIToken::setIntegerValue(APSInt IntVal) {80  this->IntVal = std::move(IntVal);81  return *this;82}83 84/// Skip the leading whitespace characters and return the updated cursor.85static Cursor skipWhitespace(Cursor C) {86  while (isblank(C.peek()))87    C.advance();88  return C;89}90 91static bool isNewlineChar(char C) { return C == '\n' || C == '\r'; }92 93/// Skip a line comment and return the updated cursor.94static Cursor skipComment(Cursor C) {95  if (C.peek() != ';')96    return C;97  while (!isNewlineChar(C.peek()) && !C.isEOF())98    C.advance();99  return C;100}101 102/// Machine operands can have comments, enclosed between /* and */.103/// This eats up all tokens, including /* and */.104static Cursor skipMachineOperandComment(Cursor C) {105  if (C.peek() != '/' || C.peek(1) != '*')106    return C;107 108  while (C.peek() != '*' || C.peek(1) != '/')109    C.advance();110 111  C.advance();112  C.advance();113  return C;114}115 116/// Return true if the given character satisfies the following regular117/// expression: [-a-zA-Z$._0-9]118static bool isIdentifierChar(char C) {119  return isalpha(C) || isdigit(C) || C == '_' || C == '-' || C == '.' ||120         C == '$';121}122 123/// Unescapes the given string value.124///125/// Expects the string value to be quoted.126static std::string unescapeQuotedString(StringRef Value) {127  assert(Value.front() == '"' && Value.back() == '"');128  Cursor C = Cursor(Value.substr(1, Value.size() - 2));129 130  std::string Str;131  Str.reserve(C.remaining().size());132  while (!C.isEOF()) {133    char Char = C.peek();134    if (Char == '\\') {135      if (C.peek(1) == '\\') {136        // Two '\' become one137        Str += '\\';138        C.advance(2);139        continue;140      }141      if (isxdigit(C.peek(1)) && isxdigit(C.peek(2))) {142        Str += hexDigitValue(C.peek(1)) * 16 + hexDigitValue(C.peek(2));143        C.advance(3);144        continue;145      }146    }147    Str += Char;148    C.advance();149  }150  return Str;151}152 153/// Lex a string constant using the following regular expression: \"[^\"]*\"154static Cursor lexStringConstant(Cursor C, ErrorCallbackType ErrorCallback) {155  assert(C.peek() == '"');156  for (C.advance(); C.peek() != '"'; C.advance()) {157    if (C.isEOF() || isNewlineChar(C.peek())) {158      ErrorCallback(159          C.location(),160          "end of machine instruction reached before the closing '\"'");161      return std::nullopt;162    }163  }164  C.advance();165  return C;166}167 168static Cursor lexName(Cursor C, MIToken &Token, MIToken::TokenKind Type,169                      unsigned PrefixLength, ErrorCallbackType ErrorCallback) {170  auto Range = C;171  C.advance(PrefixLength);172  if (C.peek() == '"') {173    if (Cursor R = lexStringConstant(C, ErrorCallback)) {174      StringRef String = Range.upto(R);175      Token.reset(Type, String)176          .setOwnedStringValue(177              unescapeQuotedString(String.drop_front(PrefixLength)));178      return R;179    }180    Token.reset(MIToken::Error, Range.remaining());181    return Range;182  }183  while (isIdentifierChar(C.peek()))184    C.advance();185  Token.reset(Type, Range.upto(C))186      .setStringValue(Range.upto(C).drop_front(PrefixLength));187  return C;188}189 190static MIToken::TokenKind getIdentifierKind(StringRef Identifier) {191  return StringSwitch<MIToken::TokenKind>(Identifier)192      .Case("_", MIToken::underscore)193      .Case("implicit", MIToken::kw_implicit)194      .Case("implicit-def", MIToken::kw_implicit_define)195      .Case("def", MIToken::kw_def)196      .Case("dead", MIToken::kw_dead)197      .Case("killed", MIToken::kw_killed)198      .Case("undef", MIToken::kw_undef)199      .Case("internal", MIToken::kw_internal)200      .Case("early-clobber", MIToken::kw_early_clobber)201      .Case("debug-use", MIToken::kw_debug_use)202      .Case("renamable", MIToken::kw_renamable)203      .Case("tied-def", MIToken::kw_tied_def)204      .Case("frame-setup", MIToken::kw_frame_setup)205      .Case("frame-destroy", MIToken::kw_frame_destroy)206      .Case("nnan", MIToken::kw_nnan)207      .Case("ninf", MIToken::kw_ninf)208      .Case("nsz", MIToken::kw_nsz)209      .Case("arcp", MIToken::kw_arcp)210      .Case("contract", MIToken::kw_contract)211      .Case("afn", MIToken::kw_afn)212      .Case("reassoc", MIToken::kw_reassoc)213      .Case("nuw", MIToken::kw_nuw)214      .Case("nsw", MIToken::kw_nsw)215      .Case("nusw", MIToken::kw_nusw)216      .Case("exact", MIToken::kw_exact)217      .Case("nneg", MIToken::kw_nneg)218      .Case("disjoint", MIToken::kw_disjoint)219      .Case("samesign", MIToken::kw_samesign)220      .Case("inbounds", MIToken::kw_inbounds)221      .Case("nofpexcept", MIToken::kw_nofpexcept)222      .Case("unpredictable", MIToken::kw_unpredictable)223      .Case("debug-location", MIToken::kw_debug_location)224      .Case("debug-instr-number", MIToken::kw_debug_instr_number)225      .Case("dbg-instr-ref", MIToken::kw_dbg_instr_ref)226      .Case("same_value", MIToken::kw_cfi_same_value)227      .Case("offset", MIToken::kw_cfi_offset)228      .Case("rel_offset", MIToken::kw_cfi_rel_offset)229      .Case("def_cfa_register", MIToken::kw_cfi_def_cfa_register)230      .Case("def_cfa_offset", MIToken::kw_cfi_def_cfa_offset)231      .Case("adjust_cfa_offset", MIToken::kw_cfi_adjust_cfa_offset)232      .Case("escape", MIToken::kw_cfi_escape)233      .Case("def_cfa", MIToken::kw_cfi_def_cfa)234      .Case("llvm_def_aspace_cfa", MIToken::kw_cfi_llvm_def_aspace_cfa)235      .Case("remember_state", MIToken::kw_cfi_remember_state)236      .Case("restore", MIToken::kw_cfi_restore)237      .Case("restore_state", MIToken::kw_cfi_restore_state)238      .Case("undefined", MIToken::kw_cfi_undefined)239      .Case("register", MIToken::kw_cfi_register)240      .Case("window_save", MIToken::kw_cfi_window_save)241      .Case("negate_ra_sign_state",242            MIToken::kw_cfi_aarch64_negate_ra_sign_state)243      .Case("negate_ra_sign_state_with_pc",244            MIToken::kw_cfi_aarch64_negate_ra_sign_state_with_pc)245      .Case("blockaddress", MIToken::kw_blockaddress)246      .Case("intrinsic", MIToken::kw_intrinsic)247      .Case("target-index", MIToken::kw_target_index)248      .Case("half", MIToken::kw_half)249      .Case("bfloat", MIToken::kw_bfloat)250      .Case("float", MIToken::kw_float)251      .Case("double", MIToken::kw_double)252      .Case("x86_fp80", MIToken::kw_x86_fp80)253      .Case("fp128", MIToken::kw_fp128)254      .Case("ppc_fp128", MIToken::kw_ppc_fp128)255      .Case("target-flags", MIToken::kw_target_flags)256      .Case("volatile", MIToken::kw_volatile)257      .Case("non-temporal", MIToken::kw_non_temporal)258      .Case("dereferenceable", MIToken::kw_dereferenceable)259      .Case("invariant", MIToken::kw_invariant)260      .Case("align", MIToken::kw_align)261      .Case("basealign", MIToken::kw_basealign)262      .Case("addrspace", MIToken::kw_addrspace)263      .Case("stack", MIToken::kw_stack)264      .Case("got", MIToken::kw_got)265      .Case("jump-table", MIToken::kw_jump_table)266      .Case("constant-pool", MIToken::kw_constant_pool)267      .Case("call-entry", MIToken::kw_call_entry)268      .Case("custom", MIToken::kw_custom)269      .Case("liveout", MIToken::kw_liveout)270      .Case("landing-pad", MIToken::kw_landing_pad)271      .Case("inlineasm-br-indirect-target",272            MIToken::kw_inlineasm_br_indirect_target)273      .Case("ehfunclet-entry", MIToken::kw_ehfunclet_entry)274      .Case("liveins", MIToken::kw_liveins)275      .Case("successors", MIToken::kw_successors)276      .Case("floatpred", MIToken::kw_floatpred)277      .Case("intpred", MIToken::kw_intpred)278      .Case("shufflemask", MIToken::kw_shufflemask)279      .Case("pre-instr-symbol", MIToken::kw_pre_instr_symbol)280      .Case("post-instr-symbol", MIToken::kw_post_instr_symbol)281      .Case("heap-alloc-marker", MIToken::kw_heap_alloc_marker)282      .Case("pcsections", MIToken::kw_pcsections)283      .Case("cfi-type", MIToken::kw_cfi_type)284      .Case("deactivation-symbol", MIToken::kw_deactivation_symbol)285      .Case("bbsections", MIToken::kw_bbsections)286      .Case("bb_id", MIToken::kw_bb_id)287      .Case("unknown-size", MIToken::kw_unknown_size)288      .Case("unknown-address", MIToken::kw_unknown_address)289      .Case("distinct", MIToken::kw_distinct)290      .Case("ir-block-address-taken", MIToken::kw_ir_block_address_taken)291      .Case("machine-block-address-taken",292            MIToken::kw_machine_block_address_taken)293      .Case("call-frame-size", MIToken::kw_call_frame_size)294      .Case("noconvergent", MIToken::kw_noconvergent)295      .Default(MIToken::Identifier);296}297 298static Cursor maybeLexIdentifier(Cursor C, MIToken &Token) {299  if (!isalpha(C.peek()) && C.peek() != '_')300    return std::nullopt;301  auto Range = C;302  while (isIdentifierChar(C.peek()))303    C.advance();304  auto Identifier = Range.upto(C);305  Token.reset(getIdentifierKind(Identifier), Identifier)306      .setStringValue(Identifier);307  return C;308}309 310static Cursor maybeLexMachineBasicBlock(Cursor C, MIToken &Token,311                                        ErrorCallbackType ErrorCallback) {312  bool IsReference = C.remaining().starts_with("%bb.");313  if (!IsReference && !C.remaining().starts_with("bb."))314    return std::nullopt;315  auto Range = C;316  unsigned PrefixLength = IsReference ? 4 : 3;317  C.advance(PrefixLength); // Skip '%bb.' or 'bb.'318  if (!isdigit(C.peek())) {319    Token.reset(MIToken::Error, C.remaining());320    ErrorCallback(C.location(), "expected a number after '%bb.'");321    return C;322  }323  auto NumberRange = C;324  while (isdigit(C.peek()))325    C.advance();326  StringRef Number = NumberRange.upto(C);327  unsigned StringOffset = PrefixLength + Number.size(); // Drop '%bb.<id>'328  // TODO: The format bb.<id>.<irname> is supported only when it's not a329  // reference. Once we deprecate the format where the irname shows up, we330  // should only lex forward if it is a reference.331  if (C.peek() == '.') {332    C.advance(); // Skip '.'333    ++StringOffset;334    while (isIdentifierChar(C.peek()))335      C.advance();336  }337  Token.reset(IsReference ? MIToken::MachineBasicBlock338                          : MIToken::MachineBasicBlockLabel,339              Range.upto(C))340      .setIntegerValue(APSInt(Number))341      .setStringValue(Range.upto(C).drop_front(StringOffset));342  return C;343}344 345static Cursor maybeLexIndex(Cursor C, MIToken &Token, StringRef Rule,346                            MIToken::TokenKind Kind) {347  if (!C.remaining().starts_with(Rule) || !isdigit(C.peek(Rule.size())))348    return std::nullopt;349  auto Range = C;350  C.advance(Rule.size());351  auto NumberRange = C;352  while (isdigit(C.peek()))353    C.advance();354  Token.reset(Kind, Range.upto(C)).setIntegerValue(APSInt(NumberRange.upto(C)));355  return C;356}357 358static Cursor maybeLexIndexAndName(Cursor C, MIToken &Token, StringRef Rule,359                                   MIToken::TokenKind Kind) {360  if (!C.remaining().starts_with(Rule) || !isdigit(C.peek(Rule.size())))361    return std::nullopt;362  auto Range = C;363  C.advance(Rule.size());364  auto NumberRange = C;365  while (isdigit(C.peek()))366    C.advance();367  StringRef Number = NumberRange.upto(C);368  unsigned StringOffset = Rule.size() + Number.size();369  if (C.peek() == '.') {370    C.advance();371    ++StringOffset;372    while (isIdentifierChar(C.peek()))373      C.advance();374  }375  Token.reset(Kind, Range.upto(C))376      .setIntegerValue(APSInt(Number))377      .setStringValue(Range.upto(C).drop_front(StringOffset));378  return C;379}380 381static Cursor maybeLexJumpTableIndex(Cursor C, MIToken &Token) {382  return maybeLexIndex(C, Token, "%jump-table.", MIToken::JumpTableIndex);383}384 385static Cursor maybeLexStackObject(Cursor C, MIToken &Token) {386  return maybeLexIndexAndName(C, Token, "%stack.", MIToken::StackObject);387}388 389static Cursor maybeLexFixedStackObject(Cursor C, MIToken &Token) {390  return maybeLexIndex(C, Token, "%fixed-stack.", MIToken::FixedStackObject);391}392 393static Cursor maybeLexConstantPoolItem(Cursor C, MIToken &Token) {394  return maybeLexIndex(C, Token, "%const.", MIToken::ConstantPoolItem);395}396 397static Cursor maybeLexSubRegisterIndex(Cursor C, MIToken &Token,398                                       ErrorCallbackType ErrorCallback) {399  const StringRef Rule = "%subreg.";400  if (!C.remaining().starts_with(Rule))401    return std::nullopt;402  return lexName(C, Token, MIToken::SubRegisterIndex, Rule.size(),403                 ErrorCallback);404}405 406static Cursor maybeLexIRBlock(Cursor C, MIToken &Token,407                              ErrorCallbackType ErrorCallback) {408  const StringRef Rule = "%ir-block.";409  if (!C.remaining().starts_with(Rule))410    return std::nullopt;411  if (isdigit(C.peek(Rule.size())))412    return maybeLexIndex(C, Token, Rule, MIToken::IRBlock);413  return lexName(C, Token, MIToken::NamedIRBlock, Rule.size(), ErrorCallback);414}415 416static Cursor maybeLexIRValue(Cursor C, MIToken &Token,417                              ErrorCallbackType ErrorCallback) {418  const StringRef Rule = "%ir.";419  if (!C.remaining().starts_with(Rule))420    return std::nullopt;421  if (isdigit(C.peek(Rule.size())))422    return maybeLexIndex(C, Token, Rule, MIToken::IRValue);423  return lexName(C, Token, MIToken::NamedIRValue, Rule.size(), ErrorCallback);424}425 426static Cursor maybeLexStringConstant(Cursor C, MIToken &Token,427                                     ErrorCallbackType ErrorCallback) {428  if (C.peek() != '"')429    return std::nullopt;430  return lexName(C, Token, MIToken::StringConstant, /*PrefixLength=*/0,431                 ErrorCallback);432}433 434static Cursor lexVirtualRegister(Cursor C, MIToken &Token) {435  auto Range = C;436  C.advance(); // Skip '%'437  auto NumberRange = C;438  while (isdigit(C.peek()))439    C.advance();440  Token.reset(MIToken::VirtualRegister, Range.upto(C))441      .setIntegerValue(APSInt(NumberRange.upto(C)));442  return C;443}444 445/// Returns true for a character allowed in a register name.446static bool isRegisterChar(char C) {447  return isIdentifierChar(C) && C != '.';448}449 450static Cursor lexNamedVirtualRegister(Cursor C, MIToken &Token) {451  Cursor Range = C;452  C.advance(); // Skip '%'453  while (isRegisterChar(C.peek()))454    C.advance();455  Token.reset(MIToken::NamedVirtualRegister, Range.upto(C))456      .setStringValue(Range.upto(C).drop_front(1)); // Drop the '%'457  return C;458}459 460static Cursor maybeLexRegister(Cursor C, MIToken &Token,461                               ErrorCallbackType ErrorCallback) {462  if (C.peek() != '%' && C.peek() != '$')463    return std::nullopt;464 465  if (C.peek() == '%') {466    if (isdigit(C.peek(1)))467      return lexVirtualRegister(C, Token);468 469    if (isRegisterChar(C.peek(1)))470      return lexNamedVirtualRegister(C, Token);471 472    return std::nullopt;473  }474 475  assert(C.peek() == '$');476  auto Range = C;477  C.advance(); // Skip '$'478  while (isRegisterChar(C.peek()))479    C.advance();480  Token.reset(MIToken::NamedRegister, Range.upto(C))481      .setStringValue(Range.upto(C).drop_front(1)); // Drop the '$'482  return C;483}484 485static Cursor maybeLexGlobalValue(Cursor C, MIToken &Token,486                                  ErrorCallbackType ErrorCallback) {487  if (C.peek() != '@')488    return std::nullopt;489  if (!isdigit(C.peek(1)))490    return lexName(C, Token, MIToken::NamedGlobalValue, /*PrefixLength=*/1,491                   ErrorCallback);492  auto Range = C;493  C.advance(1); // Skip the '@'494  auto NumberRange = C;495  while (isdigit(C.peek()))496    C.advance();497  Token.reset(MIToken::GlobalValue, Range.upto(C))498      .setIntegerValue(APSInt(NumberRange.upto(C)));499  return C;500}501 502static Cursor maybeLexExternalSymbol(Cursor C, MIToken &Token,503                                     ErrorCallbackType ErrorCallback) {504  if (C.peek() != '&')505    return std::nullopt;506  return lexName(C, Token, MIToken::ExternalSymbol, /*PrefixLength=*/1,507                 ErrorCallback);508}509 510static Cursor maybeLexMCSymbol(Cursor C, MIToken &Token,511                               ErrorCallbackType ErrorCallback) {512  const StringRef Rule = "<mcsymbol ";513  if (!C.remaining().starts_with(Rule))514    return std::nullopt;515  auto Start = C;516  C.advance(Rule.size());517 518  // Try a simple unquoted name.519  if (C.peek() != '"') {520    while (isIdentifierChar(C.peek()))521      C.advance();522    StringRef String = Start.upto(C).drop_front(Rule.size());523    if (C.peek() != '>') {524      ErrorCallback(C.location(),525                    "expected the '<mcsymbol ...' to be closed by a '>'");526      Token.reset(MIToken::Error, Start.remaining());527      return Start;528    }529    C.advance();530 531    Token.reset(MIToken::MCSymbol, Start.upto(C)).setStringValue(String);532    return C;533  }534 535  // Otherwise lex out a quoted name.536  Cursor R = lexStringConstant(C, ErrorCallback);537  if (!R) {538    ErrorCallback(C.location(),539                  "unable to parse quoted string from opening quote");540    Token.reset(MIToken::Error, Start.remaining());541    return Start;542  }543  StringRef String = Start.upto(R).drop_front(Rule.size());544  if (R.peek() != '>') {545    ErrorCallback(R.location(),546                  "expected the '<mcsymbol ...' to be closed by a '>'");547    Token.reset(MIToken::Error, Start.remaining());548    return Start;549  }550  R.advance();551 552  Token.reset(MIToken::MCSymbol, Start.upto(R))553      .setOwnedStringValue(unescapeQuotedString(String));554  return R;555}556 557static bool isValidHexFloatingPointPrefix(char C) {558  return C == 'H' || C == 'K' || C == 'L' || C == 'M' || C == 'R';559}560 561static Cursor lexFloatingPointLiteral(Cursor Range, Cursor C, MIToken &Token) {562  C.advance();563  // Skip over [0-9]*([eE][-+]?[0-9]+)?564  while (isdigit(C.peek()))565    C.advance();566  if ((C.peek() == 'e' || C.peek() == 'E') &&567      (isdigit(C.peek(1)) ||568       ((C.peek(1) == '-' || C.peek(1) == '+') && isdigit(C.peek(2))))) {569    C.advance(2);570    while (isdigit(C.peek()))571      C.advance();572  }573  Token.reset(MIToken::FloatingPointLiteral, Range.upto(C));574  return C;575}576 577static Cursor maybeLexHexadecimalLiteral(Cursor C, MIToken &Token) {578  if (C.peek() != '0' || (C.peek(1) != 'x' && C.peek(1) != 'X'))579    return std::nullopt;580  Cursor Range = C;581  C.advance(2);582  unsigned PrefLen = 2;583  if (isValidHexFloatingPointPrefix(C.peek())) {584    C.advance();585    PrefLen++;586  }587  while (isxdigit(C.peek()))588    C.advance();589  StringRef StrVal = Range.upto(C);590  if (StrVal.size() <= PrefLen)591    return std::nullopt;592  if (PrefLen == 2)593    Token.reset(MIToken::HexLiteral, Range.upto(C));594  else // It must be 3, which means that there was a floating-point prefix.595    Token.reset(MIToken::FloatingPointLiteral, Range.upto(C));596  return C;597}598 599static Cursor maybeLexNumericalLiteral(Cursor C, MIToken &Token) {600  if (!isdigit(C.peek()) && (C.peek() != '-' || !isdigit(C.peek(1))))601    return std::nullopt;602  auto Range = C;603  C.advance();604  while (isdigit(C.peek()))605    C.advance();606  if (C.peek() == '.')607    return lexFloatingPointLiteral(Range, C, Token);608  StringRef StrVal = Range.upto(C);609  Token.reset(MIToken::IntegerLiteral, StrVal).setIntegerValue(APSInt(StrVal));610  return C;611}612 613static MIToken::TokenKind getMetadataKeywordKind(StringRef Identifier) {614  return StringSwitch<MIToken::TokenKind>(Identifier)615      .Case("!tbaa", MIToken::md_tbaa)616      .Case("!alias.scope", MIToken::md_alias_scope)617      .Case("!noalias", MIToken::md_noalias)618      .Case("!range", MIToken::md_range)619      .Case("!DIExpression", MIToken::md_diexpr)620      .Case("!DILocation", MIToken::md_dilocation)621      .Case("!noalias.addrspace", MIToken::md_noalias_addrspace)622      .Default(MIToken::Error);623}624 625static Cursor maybeLexExclaim(Cursor C, MIToken &Token,626                              ErrorCallbackType ErrorCallback) {627  if (C.peek() != '!')628    return std::nullopt;629  auto Range = C;630  C.advance(1);631  if (isdigit(C.peek()) || !isIdentifierChar(C.peek())) {632    Token.reset(MIToken::exclaim, Range.upto(C));633    return C;634  }635  while (isIdentifierChar(C.peek()))636    C.advance();637  StringRef StrVal = Range.upto(C);638  Token.reset(getMetadataKeywordKind(StrVal), StrVal);639  if (Token.isError())640    ErrorCallback(Token.location(),641                  "use of unknown metadata keyword '" + StrVal + "'");642  return C;643}644 645static MIToken::TokenKind symbolToken(char C) {646  switch (C) {647  case ',':648    return MIToken::comma;649  case '.':650    return MIToken::dot;651  case '=':652    return MIToken::equal;653  case ':':654    return MIToken::colon;655  case '(':656    return MIToken::lparen;657  case ')':658    return MIToken::rparen;659  case '{':660    return MIToken::lbrace;661  case '}':662    return MIToken::rbrace;663  case '+':664    return MIToken::plus;665  case '-':666    return MIToken::minus;667  case '<':668    return MIToken::less;669  case '>':670    return MIToken::greater;671  default:672    return MIToken::Error;673  }674}675 676static Cursor maybeLexSymbol(Cursor C, MIToken &Token) {677  MIToken::TokenKind Kind;678  unsigned Length = 1;679  if (C.peek() == ':' && C.peek(1) == ':') {680    Kind = MIToken::coloncolon;681    Length = 2;682  } else683    Kind = symbolToken(C.peek());684  if (Kind == MIToken::Error)685    return std::nullopt;686  auto Range = C;687  C.advance(Length);688  Token.reset(Kind, Range.upto(C));689  return C;690}691 692static Cursor maybeLexNewline(Cursor C, MIToken &Token) {693  if (!isNewlineChar(C.peek()))694    return std::nullopt;695  auto Range = C;696  C.advance();697  Token.reset(MIToken::Newline, Range.upto(C));698  return C;699}700 701static Cursor maybeLexEscapedIRValue(Cursor C, MIToken &Token,702                                     ErrorCallbackType ErrorCallback) {703  if (C.peek() != '`')704    return std::nullopt;705  auto Range = C;706  C.advance();707  auto StrRange = C;708  while (C.peek() != '`') {709    if (C.isEOF() || isNewlineChar(C.peek())) {710      ErrorCallback(711          C.location(),712          "end of machine instruction reached before the closing '`'");713      Token.reset(MIToken::Error, Range.remaining());714      return C;715    }716    C.advance();717  }718  StringRef Value = StrRange.upto(C);719  C.advance();720  Token.reset(MIToken::QuotedIRValue, Range.upto(C)).setStringValue(Value);721  return C;722}723 724StringRef llvm::lexMIToken(StringRef Source, MIToken &Token,725                           ErrorCallbackType ErrorCallback) {726  auto C = skipComment(skipWhitespace(Cursor(Source)));727  if (C.isEOF()) {728    Token.reset(MIToken::Eof, C.remaining());729    return C.remaining();730  }731 732  C = skipWhitespace(skipMachineOperandComment(C));733 734  if (Cursor R = maybeLexMachineBasicBlock(C, Token, ErrorCallback))735    return R.remaining();736  if (Cursor R = maybeLexIdentifier(C, Token))737    return R.remaining();738  if (Cursor R = maybeLexJumpTableIndex(C, Token))739    return R.remaining();740  if (Cursor R = maybeLexStackObject(C, Token))741    return R.remaining();742  if (Cursor R = maybeLexFixedStackObject(C, Token))743    return R.remaining();744  if (Cursor R = maybeLexConstantPoolItem(C, Token))745    return R.remaining();746  if (Cursor R = maybeLexSubRegisterIndex(C, Token, ErrorCallback))747    return R.remaining();748  if (Cursor R = maybeLexIRBlock(C, Token, ErrorCallback))749    return R.remaining();750  if (Cursor R = maybeLexIRValue(C, Token, ErrorCallback))751    return R.remaining();752  if (Cursor R = maybeLexRegister(C, Token, ErrorCallback))753    return R.remaining();754  if (Cursor R = maybeLexGlobalValue(C, Token, ErrorCallback))755    return R.remaining();756  if (Cursor R = maybeLexExternalSymbol(C, Token, ErrorCallback))757    return R.remaining();758  if (Cursor R = maybeLexMCSymbol(C, Token, ErrorCallback))759    return R.remaining();760  if (Cursor R = maybeLexHexadecimalLiteral(C, Token))761    return R.remaining();762  if (Cursor R = maybeLexNumericalLiteral(C, Token))763    return R.remaining();764  if (Cursor R = maybeLexExclaim(C, Token, ErrorCallback))765    return R.remaining();766  if (Cursor R = maybeLexSymbol(C, Token))767    return R.remaining();768  if (Cursor R = maybeLexNewline(C, Token))769    return R.remaining();770  if (Cursor R = maybeLexEscapedIRValue(C, Token, ErrorCallback))771    return R.remaining();772  if (Cursor R = maybeLexStringConstant(C, Token, ErrorCallback))773    return R.remaining();774 775  Token.reset(MIToken::Error, C.remaining());776  ErrorCallback(C.location(),777                Twine("unexpected character '") + Twine(C.peek()) + "'");778  return C.remaining();779}780