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//===--------- lib/ReaderWriter/ELF/ARM/ARMExecutableWriter.h -------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLD_READER_WRITER_ELF_ARM_ARM_EXECUTABLE_WRITER_H
#define LLD_READER_WRITER_ELF_ARM_ARM_EXECUTABLE_WRITER_H
#include "ExecutableWriter.h"
#include "ARMLinkingContext.h"
#include "ARMTargetHandler.h"
#include "ARMSymbolTable.h"
#include "llvm/Support/ELF.h"
namespace {
const char *gotSymbol = "_GLOBAL_OFFSET_TABLE_";
}
namespace lld {
namespace elf {
class ARMExecutableWriter : public ExecutableWriter<ELF32LE> {
public:
ARMExecutableWriter(ARMLinkingContext &ctx, ARMTargetLayout &layout);
protected:
// Add any runtime files and their atoms to the output
void createImplicitFiles(std::vector<std::unique_ptr<File>> &) override;
void finalizeDefaultAtomValues() override;
/// \brief Create symbol table.
unique_bump_ptr<SymbolTable<ELF32LE>> createSymbolTable() override;
void processUndefinedSymbol(StringRef symName,
RuntimeFile<ELF32LE> &file) const override;
// Setup the ELF header.
std::error_code setELFHeader() override;
private:
ARMLinkingContext &_ctx;
ARMTargetLayout &_armLayout;
};
ARMExecutableWriter::ARMExecutableWriter(ARMLinkingContext &ctx,
ARMTargetLayout &layout)
: ExecutableWriter(ctx, layout), _ctx(ctx), _armLayout(layout) {}
void ARMExecutableWriter::createImplicitFiles(
std::vector<std::unique_ptr<File>> &result) {
ExecutableWriter::createImplicitFiles(result);
}
void ARMExecutableWriter::finalizeDefaultAtomValues() {
// Finalize the atom values that are part of the parent.
ExecutableWriter::finalizeDefaultAtomValues();
AtomLayout *gotAtom = _armLayout.findAbsoluteAtom(gotSymbol);
if (gotAtom) {
if (auto gotpltSection = _armLayout.findOutputSection(".got.plt"))
gotAtom->_virtualAddr = gotpltSection->virtualAddr();
else if (auto gotSection = _armLayout.findOutputSection(".got"))
gotAtom->_virtualAddr = gotSection->virtualAddr();
else
gotAtom->_virtualAddr = 0;
}
// TODO: resolve addresses of __exidx_start/_end atoms
}
unique_bump_ptr<SymbolTable<ELF32LE>> ARMExecutableWriter::createSymbolTable() {
return unique_bump_ptr<SymbolTable<ELF32LE>>(new (_alloc)
ARMSymbolTable(_ctx));
}
void ARMExecutableWriter::processUndefinedSymbol(
StringRef symName, RuntimeFile<ELF32LE> &file) const {
if (symName == gotSymbol) {
file.addAbsoluteAtom(gotSymbol);
} else if (symName.startswith("__exidx")) {
file.addAbsoluteAtom("__exidx_start");
file.addAbsoluteAtom("__exidx_end");
}
}
std::error_code ARMExecutableWriter::setELFHeader() {
if (std::error_code ec = ExecutableWriter::setELFHeader())
return ec;
// Set ARM-specific flags.
_elfHeader->e_flags(llvm::ELF::EF_ARM_EABI_VER5 |
llvm::ELF::EF_ARM_VFP_FLOAT);
StringRef entryName = _ctx.entrySymbolName();
if (const AtomLayout *al = _armLayout.findAtomLayoutByName(entryName)) {
if (const auto *ea = dyn_cast<DefinedAtom>(al->_atom)) {
switch (ea->codeModel()) {
case DefinedAtom::codeNA:
if (al->_virtualAddr & 0x3) {
llvm::report_fatal_error(
"Two least bits must be zero for ARM entry point");
}
break;
case DefinedAtom::codeARMThumb:
// Fixup entry point for Thumb code.
_elfHeader->e_entry(al->_virtualAddr | 0x1);
break;
default:
llvm_unreachable("Wrong code model of entry point atom");
}
}
}
return std::error_code();
}
} // namespace elf
} // namespace lld
#endif // LLD_READER_WRITER_ELF_ARM_ARM_EXECUTABLE_WRITER_H
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