llvm/lib/ObjCopy/XCOFF/XCOFFWriter.cpp

   1 //===- XCOFFWriter.cpp ----------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/Support/Errc.h"
  10 #include "XCOFFWriter.h"
  11
  12 namespace llvm {
  13 namespace objcopy {
  14 namespace xcoff {
  15
  16 using namespace object;
  17
  18 void XCOFFWriter::finalizeHeaders() {
  19   // File header.
  20   FileSize += sizeof(XCOFFFileHeader32);
  21   // Optional file header.
  22   FileSize += Obj.FileHeader.AuxHeaderSize;
  23   // Section headers.
  24   FileSize += sizeof(XCOFFSectionHeader32) * Obj.Sections.size();
  25 }
  26
  27 void XCOFFWriter::finalizeSections() {
  28   for (const Section &Sec : Obj.Sections) {
  29     // Section data.
  30     FileSize += Sec.Contents.size();
  31     // Relocations.
  32     FileSize +=
  33         Sec.SectionHeader.NumberOfRelocations * sizeof(XCOFFRelocation32);
  34   }
  35 }
  36
  37 void XCOFFWriter::finalizeSymbolStringTable() {
  38   assert(Obj.FileHeader.SymbolTableOffset >= FileSize);
  39   FileSize = Obj.FileHeader.SymbolTableOffset;
  40   // Symbols and auxiliary entries.
  41   FileSize +=
  42       Obj.FileHeader.NumberOfSymTableEntries * XCOFF::SymbolTableEntrySize;
  43   // String table.
  44   FileSize += Obj.StringTable.size();
  45 }
  46
  47 void XCOFFWriter::finalize() {
  48   FileSize = 0;
  49   finalizeHeaders();
  50   finalizeSections();
  51   finalizeSymbolStringTable();
  52 }
  53
  54 void XCOFFWriter::writeHeaders() {
  55   // Write the file header.
  56   uint8_t *Ptr = reinterpret_cast<uint8_t *>(Buf->getBufferStart());
  57   memcpy(Ptr, &Obj.FileHeader, sizeof(XCOFFFileHeader32));
  58   Ptr += sizeof(XCOFFFileHeader32);
  59
  60   // Write the optional header.
  61   if (Obj.FileHeader.AuxHeaderSize) {
  62     memcpy(Ptr, &Obj.OptionalFileHeader, Obj.FileHeader.AuxHeaderSize);
  63     Ptr += Obj.FileHeader.AuxHeaderSize;
  64   }
  65
  66   // Write section headers.
  67   for (const Section &Sec : Obj.Sections) {
  68     memcpy(Ptr, &Sec.SectionHeader, sizeof(XCOFFSectionHeader32));
  69     Ptr += sizeof(XCOFFSectionHeader32);
  70   }
  71 }
  72
  73 void XCOFFWriter::writeSections() {
  74   // Write section data.
  75   for (const Section &Sec : Obj.Sections) {
  76     uint8_t *Ptr = reinterpret_cast<uint8_t *>(Buf->getBufferStart()) +
  77                    Sec.SectionHeader.FileOffsetToRawData;
  78     Ptr = std::copy(Sec.Contents.begin(), Sec.Contents.end(), Ptr);
  79   }
  80
  81   // Write relocations.
  82   for (const Section &Sec : Obj.Sections) {
  83     uint8_t *Ptr = reinterpret_cast<uint8_t *>(Buf->getBufferStart()) +
  84                    Sec.SectionHeader.FileOffsetToRelocationInfo;
  85     for (const XCOFFRelocation32 &Rel : Sec.Relocations) {
  86       memcpy(Ptr, &Rel, sizeof(XCOFFRelocation32));
  87       Ptr += sizeof(XCOFFRelocation32);
  88     }
  89   }
  90 }
  91
  92 void XCOFFWriter::writeSymbolStringTable() {
  93   // Write symbols.
  94   uint8_t *Ptr = reinterpret_cast<uint8_t *>(Buf->getBufferStart()) +
  95                  Obj.FileHeader.SymbolTableOffset;
  96   for (const Symbol &Sym : Obj.Symbols) {
  97     memcpy(Ptr, &Sym.Sym, XCOFF::SymbolTableEntrySize);
  98     Ptr += XCOFF::SymbolTableEntrySize;
  99     // Auxiliary symbols.
 100     memcpy(Ptr, Sym.AuxSymbolEntries.data(), Sym.AuxSymbolEntries.size());
 101     Ptr += Sym.AuxSymbolEntries.size();
 102   }
 103   // Write the string table.
 104   memcpy(Ptr, Obj.StringTable.data(), Obj.StringTable.size());
 105   Ptr += Obj.StringTable.size();
 106 }
 107
 108 Error XCOFFWriter::write() {
 109   finalize();
 110   Buf = WritableMemoryBuffer::getNewMemBuffer(FileSize);
 111   if (!Buf)
 112     return createStringError(errc::not_enough_memory,
 113                              "failed to allocate memory buffer of " +
 114                                  Twine::utohexstr(FileSize) + " bytes");
 115
 116   writeHeaders();
 117   writeSections();
 118   writeSymbolStringTable();
 119   Out.write(Buf->getBufferStart(), Buf->getBufferSize());
 120   return Error::success();
 121 }
 122
 123 } // end namespace xcoff
 124 } // end namespace objcopy
 125 } // end namespace llvm