llvm-project

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//===-- llvm-c++filt.cpp --------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/Demangle/Demangle.h"
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#include "llvm/Demangle/StringViewExtras.h"
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#include "llvm/Option/Arg.h"
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#include "llvm/Option/ArgList.h"
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#include "llvm/Option/Option.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/LLVMDriver.h"
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#include "llvm/Support/WithColor.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/TargetParser/Host.h"
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#include "llvm/TargetParser/Triple.h"
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#include <cstdlib>
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#include <iostream>
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using namespace llvm;
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namespace {
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enum ID {
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  OPT_INVALID = 0, // This is not an option ID.
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#define OPTION(...) LLVM_MAKE_OPT_ID(__VA_ARGS__),
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#include "Opts.inc"
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#undef OPTION
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};
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#define PREFIX(NAME, VALUE)                                                    \
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  static constexpr llvm::StringLiteral NAME##_init[] = VALUE;                  \
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  static constexpr llvm::ArrayRef<llvm::StringLiteral> NAME(                   \
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      NAME##_init, std::size(NAME##_init) - 1);
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#include "Opts.inc"
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#undef PREFIX
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using namespace llvm::opt;
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static constexpr opt::OptTable::Info InfoTable[] = {
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#define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
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#include "Opts.inc"
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#undef OPTION
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};
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class CxxfiltOptTable : public opt::GenericOptTable {
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public:
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  CxxfiltOptTable() : opt::GenericOptTable(InfoTable) {
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    setGroupedShortOptions(true);
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  }
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};
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} // namespace
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static bool ParseParams;
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static bool StripUnderscore;
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static bool Types;
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static StringRef ToolName;
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static void error(const Twine &Message) {
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  WithColor::error(errs(), ToolName) << Message << '\n';
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  exit(1);
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}
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static std::string demangle(const std::string &Mangled) {
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  using llvm::itanium_demangle::starts_with;
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  std::string_view DecoratedStr = Mangled;
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  bool CanHaveLeadingDot = true;
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  if (StripUnderscore && DecoratedStr[0] == '_') {
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    DecoratedStr.remove_prefix(1);
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    CanHaveLeadingDot = false;
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  }
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  std::string Result;
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  if (nonMicrosoftDemangle(DecoratedStr, Result, CanHaveLeadingDot,
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                           ParseParams))
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    return Result;
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  std::string Prefix;
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  char *Undecorated = nullptr;
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  if (Types)
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    Undecorated = itaniumDemangle(DecoratedStr, ParseParams);
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  if (!Undecorated && starts_with(DecoratedStr, "__imp_")) {
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    Prefix = "import thunk for ";
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    Undecorated = itaniumDemangle(DecoratedStr.substr(6), ParseParams);
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  }
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  Result = Undecorated ? Prefix + Undecorated : Mangled;
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  free(Undecorated);
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  return Result;
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}
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// Split 'Source' on any character that fails to pass 'IsLegalChar'.  The
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// returned vector consists of pairs where 'first' is the delimited word, and
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// 'second' are the delimiters following that word.
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static void SplitStringDelims(
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    StringRef Source,
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    SmallVectorImpl<std::pair<StringRef, StringRef>> &OutFragments,
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    function_ref<bool(char)> IsLegalChar) {
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  // The beginning of the input string.
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  const auto Head = Source.begin();
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  // Obtain any leading delimiters.
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  auto Start = std::find_if(Head, Source.end(), IsLegalChar);
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  if (Start != Head)
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    OutFragments.push_back({"", Source.slice(0, Start - Head)});
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  // Capture each word and the delimiters following that word.
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  while (Start != Source.end()) {
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    Start = std::find_if(Start, Source.end(), IsLegalChar);
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    auto End = std::find_if_not(Start, Source.end(), IsLegalChar);
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    auto DEnd = std::find_if(End, Source.end(), IsLegalChar);
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    OutFragments.push_back({Source.slice(Start - Head, End - Head),
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                            Source.slice(End - Head, DEnd - Head)});
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    Start = DEnd;
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  }
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}
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// This returns true if 'C' is a character that can show up in an
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// Itanium-mangled string.
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static bool IsLegalItaniumChar(char C) {
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  // Itanium CXX ABI [External Names]p5.1.1:
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  // '$' and '.' in mangled names are reserved for private implementations.
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  return isAlnum(C) || C == '.' || C == '$' || C == '_';
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}
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// If 'Split' is true, then 'Mangled' is broken into individual words and each
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// word is demangled.  Otherwise, the entire string is treated as a single
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// mangled item.  The result is output to 'OS'.
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static void demangleLine(llvm::raw_ostream &OS, StringRef Mangled, bool Split) {
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  std::string Result;
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  if (Split) {
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    SmallVector<std::pair<StringRef, StringRef>, 16> Words;
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    SplitStringDelims(Mangled, Words, IsLegalItaniumChar);
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    for (const auto &Word : Words)
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      Result += ::demangle(std::string(Word.first)) + Word.second.str();
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  } else
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    Result = ::demangle(std::string(Mangled));
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  OS << Result << '\n';
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  OS.flush();
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}
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int llvm_cxxfilt_main(int argc, char **argv, const llvm::ToolContext &) {
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  BumpPtrAllocator A;
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  StringSaver Saver(A);
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  CxxfiltOptTable Tbl;
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  ToolName = argv[0];
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  opt::InputArgList Args = Tbl.parseArgs(argc, argv, OPT_UNKNOWN, Saver,
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                                         [&](StringRef Msg) { error(Msg); });
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  if (Args.hasArg(OPT_help)) {
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    Tbl.printHelp(outs(),
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                  (Twine(ToolName) + " [options] <mangled>").str().c_str(),
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                  "LLVM symbol undecoration tool");
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    // TODO Replace this with OptTable API once it adds extrahelp support.
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    outs() << "\nPass @FILE as argument to read options from FILE.\n";
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    return 0;
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  }
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  if (Args.hasArg(OPT_version)) {
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    outs() << ToolName << '\n';
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    cl::PrintVersionMessage();
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    return 0;
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  }
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  // The default value depends on the default triple. Mach-O has symbols
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  // prefixed with "_", so strip by default.
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  if (opt::Arg *A =
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          Args.getLastArg(OPT_strip_underscore, OPT_no_strip_underscore))
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    StripUnderscore = A->getOption().matches(OPT_strip_underscore);
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  else
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    StripUnderscore = Triple(sys::getProcessTriple()).isOSBinFormatMachO();
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  ParseParams = !Args.hasArg(OPT_no_params);
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  Types = Args.hasArg(OPT_types);
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  std::vector<std::string> Decorated = Args.getAllArgValues(OPT_INPUT);
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  if (Decorated.empty())
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    for (std::string Mangled; std::getline(std::cin, Mangled);)
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      demangleLine(llvm::outs(), Mangled, true);
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  else
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    for (const auto &Symbol : Decorated)
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      demangleLine(llvm::outs(), Symbol, false);
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  return EXIT_SUCCESS;
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}
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