diff options
Diffstat (limited to 'contrib/llvm/tools/llvm-objcopy/COFF/Writer.cpp')
| -rw-r--r-- | contrib/llvm/tools/llvm-objcopy/COFF/Writer.cpp | 337 |
1 files changed, 337 insertions, 0 deletions
diff --git a/contrib/llvm/tools/llvm-objcopy/COFF/Writer.cpp b/contrib/llvm/tools/llvm-objcopy/COFF/Writer.cpp new file mode 100644 index 000000000000..385d43b1bae5 --- /dev/null +++ b/contrib/llvm/tools/llvm-objcopy/COFF/Writer.cpp @@ -0,0 +1,337 @@ +//===- Writer.cpp ---------------------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#include "Writer.h" +#include "Object.h" +#include "llvm-objcopy.h" +#include "llvm/ADT/ArrayRef.h" +#include "llvm/ADT/StringRef.h" +#include "llvm/BinaryFormat/COFF.h" +#include "llvm/Object/COFF.h" +#include "llvm/Support/ErrorHandling.h" +#include <cstddef> +#include <cstdint> + +namespace llvm { +namespace objcopy { +namespace coff { + +using namespace object; +using namespace COFF; + +Error COFFWriter::finalizeRelocTargets() { + for (Section &Sec : Obj.Sections) { + for (Relocation &R : Sec.Relocs) { + const Symbol *Sym = Obj.findSymbol(R.Target); + if (Sym == nullptr) + return make_error<StringError>("Relocation target " + R.TargetName + + " (" + Twine(R.Target) + + ") not found", + object_error::invalid_symbol_index); + R.Reloc.SymbolTableIndex = Sym->RawIndex; + } + } + return Error::success(); +} + +void COFFWriter::layoutSections() { + for (auto &S : Obj.Sections) { + if (S.Header.SizeOfRawData > 0) + S.Header.PointerToRawData = FileSize; + FileSize += S.Header.SizeOfRawData; // For executables, this is already + // aligned to FileAlignment. + S.Header.NumberOfRelocations = S.Relocs.size(); + S.Header.PointerToRelocations = + S.Header.NumberOfRelocations > 0 ? FileSize : 0; + FileSize += S.Relocs.size() * sizeof(coff_relocation); + FileSize = alignTo(FileSize, FileAlignment); + + if (S.Header.Characteristics & IMAGE_SCN_CNT_INITIALIZED_DATA) + SizeOfInitializedData += S.Header.SizeOfRawData; + } +} + +size_t COFFWriter::finalizeStringTable() { + for (auto &S : Obj.Sections) + if (S.Name.size() > COFF::NameSize) + StrTabBuilder.add(S.Name); + + for (const auto &S : Obj.getSymbols()) + if (S.Name.size() > COFF::NameSize) + StrTabBuilder.add(S.Name); + + StrTabBuilder.finalize(); + + for (auto &S : Obj.Sections) { + if (S.Name.size() > COFF::NameSize) { + snprintf(S.Header.Name, sizeof(S.Header.Name), "/%d", + (int)StrTabBuilder.getOffset(S.Name)); + } else { + strncpy(S.Header.Name, S.Name.data(), COFF::NameSize); + } + } + for (auto &S : Obj.getMutableSymbols()) { + if (S.Name.size() > COFF::NameSize) { + S.Sym.Name.Offset.Zeroes = 0; + S.Sym.Name.Offset.Offset = StrTabBuilder.getOffset(S.Name); + } else { + strncpy(S.Sym.Name.ShortName, S.Name.data(), COFF::NameSize); + } + } + return StrTabBuilder.getSize(); +} + +template <class SymbolTy> +std::pair<size_t, size_t> COFFWriter::finalizeSymbolTable() { + size_t SymTabSize = Obj.getSymbols().size() * sizeof(SymbolTy); + for (const auto &S : Obj.getSymbols()) + SymTabSize += S.AuxData.size(); + return std::make_pair(SymTabSize, sizeof(SymbolTy)); +} + +Error COFFWriter::finalize(bool IsBigObj) { + if (Error E = finalizeRelocTargets()) + return E; + + size_t SizeOfHeaders = 0; + FileAlignment = 1; + size_t PeHeaderSize = 0; + if (Obj.IsPE) { + Obj.DosHeader.AddressOfNewExeHeader = + sizeof(Obj.DosHeader) + Obj.DosStub.size(); + SizeOfHeaders += Obj.DosHeader.AddressOfNewExeHeader + sizeof(PEMagic); + + FileAlignment = Obj.PeHeader.FileAlignment; + Obj.PeHeader.NumberOfRvaAndSize = Obj.DataDirectories.size(); + + PeHeaderSize = Obj.Is64 ? sizeof(pe32plus_header) : sizeof(pe32_header); + SizeOfHeaders += + PeHeaderSize + sizeof(data_directory) * Obj.DataDirectories.size(); + } + Obj.CoffFileHeader.NumberOfSections = Obj.Sections.size(); + SizeOfHeaders += + IsBigObj ? sizeof(coff_bigobj_file_header) : sizeof(coff_file_header); + SizeOfHeaders += sizeof(coff_section) * Obj.Sections.size(); + SizeOfHeaders = alignTo(SizeOfHeaders, FileAlignment); + + Obj.CoffFileHeader.SizeOfOptionalHeader = + PeHeaderSize + sizeof(data_directory) * Obj.DataDirectories.size(); + + FileSize = SizeOfHeaders; + SizeOfInitializedData = 0; + + layoutSections(); + + if (Obj.IsPE) { + Obj.PeHeader.SizeOfHeaders = SizeOfHeaders; + Obj.PeHeader.SizeOfInitializedData = SizeOfInitializedData; + + if (!Obj.Sections.empty()) { + const Section &S = Obj.Sections.back(); + Obj.PeHeader.SizeOfImage = + alignTo(S.Header.VirtualAddress + S.Header.VirtualSize, + Obj.PeHeader.SectionAlignment); + } + + // If the PE header had a checksum, clear it, since it isn't valid + // any longer. (We don't calculate a new one.) + Obj.PeHeader.CheckSum = 0; + } + + size_t StrTabSize = finalizeStringTable(); + size_t SymTabSize, SymbolSize; + std::tie(SymTabSize, SymbolSize) = IsBigObj + ? finalizeSymbolTable<coff_symbol32>() + : finalizeSymbolTable<coff_symbol16>(); + + size_t PointerToSymbolTable = FileSize; + // StrTabSize <= 4 is the size of an empty string table, only consisting + // of the length field. + if (SymTabSize == 0 && StrTabSize <= 4 && Obj.IsPE) { + // For executables, don't point to the symbol table and skip writing + // the length field, if both the symbol and string tables are empty. + PointerToSymbolTable = 0; + StrTabSize = 0; + } + + size_t NumRawSymbols = SymTabSize / SymbolSize; + Obj.CoffFileHeader.PointerToSymbolTable = PointerToSymbolTable; + Obj.CoffFileHeader.NumberOfSymbols = NumRawSymbols; + FileSize += SymTabSize + StrTabSize; + FileSize = alignTo(FileSize, FileAlignment); + + return Error::success(); +} + +void COFFWriter::writeHeaders(bool IsBigObj) { + uint8_t *Ptr = Buf.getBufferStart(); + if (Obj.IsPE) { + memcpy(Ptr, &Obj.DosHeader, sizeof(Obj.DosHeader)); + Ptr += sizeof(Obj.DosHeader); + memcpy(Ptr, Obj.DosStub.data(), Obj.DosStub.size()); + Ptr += Obj.DosStub.size(); + memcpy(Ptr, PEMagic, sizeof(PEMagic)); + Ptr += sizeof(PEMagic); + } + if (!IsBigObj) { + memcpy(Ptr, &Obj.CoffFileHeader, sizeof(Obj.CoffFileHeader)); + Ptr += sizeof(Obj.CoffFileHeader); + } else { + // Generate a coff_bigobj_file_header, filling it in with the values + // from Obj.CoffFileHeader. All extra fields that don't exist in + // coff_file_header can be set to hardcoded values. + coff_bigobj_file_header BigObjHeader; + BigObjHeader.Sig1 = IMAGE_FILE_MACHINE_UNKNOWN; + BigObjHeader.Sig2 = 0xffff; + BigObjHeader.Version = BigObjHeader::MinBigObjectVersion; + BigObjHeader.Machine = Obj.CoffFileHeader.Machine; + BigObjHeader.TimeDateStamp = Obj.CoffFileHeader.TimeDateStamp; + memcpy(BigObjHeader.UUID, BigObjMagic, sizeof(BigObjMagic)); + BigObjHeader.unused1 = 0; + BigObjHeader.unused2 = 0; + BigObjHeader.unused3 = 0; + BigObjHeader.unused4 = 0; + // The value in Obj.CoffFileHeader.NumberOfSections is truncated, thus + // get the original one instead. + BigObjHeader.NumberOfSections = Obj.Sections.size(); + BigObjHeader.PointerToSymbolTable = Obj.CoffFileHeader.PointerToSymbolTable; + BigObjHeader.NumberOfSymbols = Obj.CoffFileHeader.NumberOfSymbols; + + memcpy(Ptr, &BigObjHeader, sizeof(BigObjHeader)); + Ptr += sizeof(BigObjHeader); + } + if (Obj.IsPE) { + if (Obj.Is64) { + memcpy(Ptr, &Obj.PeHeader, sizeof(Obj.PeHeader)); + Ptr += sizeof(Obj.PeHeader); + } else { + pe32_header PeHeader; + copyPeHeader(PeHeader, Obj.PeHeader); + // The pe32plus_header (stored in Object) lacks the BaseOfData field. + PeHeader.BaseOfData = Obj.BaseOfData; + + memcpy(Ptr, &PeHeader, sizeof(PeHeader)); + Ptr += sizeof(PeHeader); + } + for (const auto &DD : Obj.DataDirectories) { + memcpy(Ptr, &DD, sizeof(DD)); + Ptr += sizeof(DD); + } + } + for (const auto &S : Obj.Sections) { + memcpy(Ptr, &S.Header, sizeof(S.Header)); + Ptr += sizeof(S.Header); + } +} + +void COFFWriter::writeSections() { + for (const auto &S : Obj.Sections) { + uint8_t *Ptr = Buf.getBufferStart() + S.Header.PointerToRawData; + std::copy(S.Contents.begin(), S.Contents.end(), Ptr); + + // For executable sections, pad the remainder of the raw data size with + // 0xcc, which is int3 on x86. + if ((S.Header.Characteristics & IMAGE_SCN_CNT_CODE) && + S.Header.SizeOfRawData > S.Contents.size()) + memset(Ptr + S.Contents.size(), 0xcc, + S.Header.SizeOfRawData - S.Contents.size()); + + Ptr += S.Header.SizeOfRawData; + for (const auto &R : S.Relocs) { + memcpy(Ptr, &R.Reloc, sizeof(R.Reloc)); + Ptr += sizeof(R.Reloc); + } + } +} + +template <class SymbolTy> void COFFWriter::writeSymbolStringTables() { + uint8_t *Ptr = Buf.getBufferStart() + Obj.CoffFileHeader.PointerToSymbolTable; + for (const auto &S : Obj.getSymbols()) { + // Convert symbols back to the right size, from coff_symbol32. + copySymbol<SymbolTy, coff_symbol32>(*reinterpret_cast<SymbolTy *>(Ptr), + S.Sym); + Ptr += sizeof(SymbolTy); + std::copy(S.AuxData.begin(), S.AuxData.end(), Ptr); + Ptr += S.AuxData.size(); + } + if (StrTabBuilder.getSize() > 4 || !Obj.IsPE) { + // Always write a string table in object files, even an empty one. + StrTabBuilder.write(Ptr); + Ptr += StrTabBuilder.getSize(); + } +} + +Error COFFWriter::write(bool IsBigObj) { + if (Error E = finalize(IsBigObj)) + return E; + + Buf.allocate(FileSize); + + writeHeaders(IsBigObj); + writeSections(); + if (IsBigObj) + writeSymbolStringTables<coff_symbol32>(); + else + writeSymbolStringTables<coff_symbol16>(); + + if (Obj.IsPE) + if (Error E = patchDebugDirectory()) + return E; + + return Buf.commit(); +} + +// Locate which sections contain the debug directories, iterate over all +// the debug_directory structs in there, and set the PointerToRawData field +// in all of them, according to their new physical location in the file. +Error COFFWriter::patchDebugDirectory() { + if (Obj.DataDirectories.size() < DEBUG_DIRECTORY) + return Error::success(); + const data_directory *Dir = &Obj.DataDirectories[DEBUG_DIRECTORY]; + if (Dir->Size <= 0) + return Error::success(); + for (const auto &S : Obj.Sections) { + if (Dir->RelativeVirtualAddress >= S.Header.VirtualAddress && + Dir->RelativeVirtualAddress < + S.Header.VirtualAddress + S.Header.SizeOfRawData) { + if (Dir->RelativeVirtualAddress + Dir->Size > + S.Header.VirtualAddress + S.Header.SizeOfRawData) + return make_error<StringError>( + "Debug directory extends past end of section", + object_error::parse_failed); + + size_t Offset = Dir->RelativeVirtualAddress - S.Header.VirtualAddress; + uint8_t *Ptr = Buf.getBufferStart() + S.Header.PointerToRawData + Offset; + uint8_t *End = Ptr + Dir->Size; + while (Ptr < End) { + debug_directory *Debug = reinterpret_cast<debug_directory *>(Ptr); + Debug->PointerToRawData = + S.Header.PointerToRawData + Offset + sizeof(debug_directory); + Ptr += sizeof(debug_directory) + Debug->SizeOfData; + Offset += sizeof(debug_directory) + Debug->SizeOfData; + } + // Debug directory found and patched, all done. + return Error::success(); + } + } + return make_error<StringError>("Debug directory not found", + object_error::parse_failed); +} + +Error COFFWriter::write() { + bool IsBigObj = Obj.Sections.size() > MaxNumberOfSections16; + if (IsBigObj && Obj.IsPE) + return make_error<StringError>("Too many sections for executable", + object_error::parse_failed); + return write(IsBigObj); +} + +} // end namespace coff +} // end namespace objcopy +} // end namespace llvm |