ELFConfig.cpp
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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