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//===- ELFConfig.cpp ------------------------------------------------------===// 
// 
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 
// See https://llvm.org/LICENSE.txt for license information. 
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 
// 
//===----------------------------------------------------------------------===// 
 
#include "CopyConfig.h" 
#include "llvm/ADT/Optional.h" 
#include "llvm/ADT/StringSwitch.h" 
#include "llvm/Support/Errc.h" 
#include "llvm/Support/Error.h" 
 
namespace llvm { 
namespace objcopy { 
namespace elf { 
 
static Expected<NewSymbolInfo> parseNewSymbolInfo(StringRef FlagValue, 
                                                  uint8_t DefaultVisibility) { 
  // Parse value given with --add-symbol option and create the 
  // new symbol if possible. The value format for --add-symbol is: 
  // 
  // <name>=[<section>:]<value>[,<flags>] 
  // 
  // where: 
  // <name> - symbol name, can be empty string 
  // <section> - optional section name. If not given ABS symbol is created 
  // <value> - symbol value, can be decimal or hexadecimal number prefixed 
  //           with 0x. 
  // <flags> - optional flags affecting symbol type, binding or visibility: 
  //           The following are currently supported: 
  // 
  //           global, local, weak, default, hidden, file, section, object, 
  //           indirect-function. 
  // 
  //           The following flags are ignored and provided for GNU 
  //           compatibility only: 
  // 
  //           warning, debug, constructor, indirect, synthetic, 
  //           unique-object, before=<symbol>. 
  NewSymbolInfo SI; 
  StringRef Value; 
  std::tie(SI.SymbolName, Value) = FlagValue.split('='); 
  if (Value.empty()) 
    return createStringError( 
        errc::invalid_argument, 
        "bad format for --add-symbol, missing '=' after '%s'", 
        SI.SymbolName.str().c_str()); 
 
  if (Value.contains(':')) { 
    std::tie(SI.SectionName, Value) = Value.split(':'); 
    if (SI.SectionName.empty() || Value.empty()) 
      return createStringError( 
          errc::invalid_argument, 
          "bad format for --add-symbol, missing section name or symbol value"); 
  } 
 
  SmallVector<StringRef, 6> Flags; 
  Value.split(Flags, ','); 
  if (Flags[0].getAsInteger(0, SI.Value)) 
    return createStringError(errc::invalid_argument, "bad symbol value: '%s'", 
                             Flags[0].str().c_str()); 
 
  SI.Visibility = DefaultVisibility; 
 
  using Functor = std::function<void(void)>; 
  SmallVector<StringRef, 6> UnsupportedFlags; 
  for (size_t I = 1, NumFlags = Flags.size(); I < NumFlags; ++I) 
    static_cast<Functor>( 
        StringSwitch<Functor>(Flags[I]) 
            .CaseLower("global", [&SI] { SI.Bind = ELF::STB_GLOBAL; }) 
            .CaseLower("local", [&SI] { SI.Bind = ELF::STB_LOCAL; }) 
            .CaseLower("weak", [&SI] { SI.Bind = ELF::STB_WEAK; }) 
            .CaseLower("default", [&SI] { SI.Visibility = ELF::STV_DEFAULT; }) 
            .CaseLower("hidden", [&SI] { SI.Visibility = ELF::STV_HIDDEN; }) 
            .CaseLower("protected", 
                       [&SI] { SI.Visibility = ELF::STV_PROTECTED; }) 
            .CaseLower("file", [&SI] { SI.Type = ELF::STT_FILE; }) 
            .CaseLower("section", [&SI] { SI.Type = ELF::STT_SECTION; }) 
            .CaseLower("object", [&SI] { SI.Type = ELF::STT_OBJECT; }) 
            .CaseLower("function", [&SI] { SI.Type = ELF::STT_FUNC; }) 
            .CaseLower("indirect-function", 
                       [&SI] { SI.Type = ELF::STT_GNU_IFUNC; }) 
            .CaseLower("debug", [] {}) 
            .CaseLower("constructor", [] {}) 
            .CaseLower("warning", [] {}) 
            .CaseLower("indirect", [] {}) 
            .CaseLower("synthetic", [] {}) 
            .CaseLower("unique-object", [] {}) 
            .StartsWithLower("before", [] {}) 
            .Default([&] { UnsupportedFlags.push_back(Flags[I]); }))(); 
  if (!UnsupportedFlags.empty()) 
    return createStringError(errc::invalid_argument, 
                             "unsupported flag%s for --add-symbol: '%s'", 
                             UnsupportedFlags.size() > 1 ? "s" : "", 
                             join(UnsupportedFlags, "', '").c_str()); 
  return SI; 
} 
 
Expected<ELFCopyConfig> parseConfig(const CopyConfig &Config) { 
  ELFCopyConfig ELFConfig; 
  if (Config.NewSymbolVisibility) { 
    const uint8_t Invalid = 0xff; 
    ELFConfig.NewSymbolVisibility = 
        StringSwitch<uint8_t>(*Config.NewSymbolVisibility) 
            .Case("default", ELF::STV_DEFAULT) 
            .Case("hidden", ELF::STV_HIDDEN) 
            .Case("internal", ELF::STV_INTERNAL) 
            .Case("protected", ELF::STV_PROTECTED) 
            .Default(Invalid); 
 
    if (ELFConfig.NewSymbolVisibility == Invalid) 
      return createStringError(errc::invalid_argument, 
                               "'%s' is not a valid symbol visibility", 
                               Config.NewSymbolVisibility->str().c_str()); 
  } 
 
  for (StringRef Arg : Config.SymbolsToAdd) { 
    Expected<elf::NewSymbolInfo> NSI = parseNewSymbolInfo( 
        Arg, 
        ELFConfig.NewSymbolVisibility.getValueOr((uint8_t)ELF::STV_DEFAULT)); 
    if (!NSI) 
      return NSI.takeError(); 
    ELFConfig.SymbolsToAdd.push_back(*NSI); 
  } 
 
  return ELFConfig; 
} 
 
} // end namespace elf 
} // end namespace objcopy 
} // end namespace llvm