/// <summary>
/// Emit the .reloc section based on file relocation information in the individual blocks.
/// We rely on the fact that the .reloc section is emitted last so that, by the time
/// it's getting serialized, all other sections that may contain relocations have already
/// been laid out.
/// </summary>
private BlobBuilder SerializeRelocationSection(SectionLocation sectionLocation)
{
// There are 12 bits for the relative offset
const int RelocationTypeShift = 12;
const int MaxRelativeOffsetInBlock = (1 << RelocationTypeShift) - 1;
// Even though the format doesn't dictate it, it seems customary
// to align the base RVA's on 4K boundaries.
const int BaseRVAAlignment = 1 << RelocationTypeShift;
BlobBuilder builder = new BlobBuilder();
int baseRVA = 0;
List <ushort> offsetsAndTypes = null;
Section relocSection = FindSection(R2RPEBuilder.RelocSectionName);
if (relocSection != null)
{
relocSection.FilePosWhenPlaced = sectionLocation.PointerToRawData;
relocSection.RVAWhenPlaced = sectionLocation.RelativeVirtualAddress;
builder = relocSection.Content;
}
// Traverse relocations in all sections in their RVA order
// By now, all "normal" sections with relocations should already have been laid out
foreach (Section section in _sections.OrderBy((sec) => sec.RVAWhenPlaced))
{
foreach (PlacedObjectData placedObjectData in section.PlacedObjectDataToRelocate)
{
for (int relocIndex = 0; relocIndex < placedObjectData.Relocs.Length; relocIndex++)
{
RelocType relocType = placedObjectData.Relocs[relocIndex].RelocType;
RelocType fileRelocType = Relocation.GetFileRelocationType(relocType);
if (fileRelocType != RelocType.IMAGE_REL_BASED_ABSOLUTE)
{
int relocationRVA = section.RVAWhenPlaced + placedObjectData.Offset + placedObjectData.Relocs[relocIndex].Offset;
if (offsetsAndTypes != null && relocationRVA - baseRVA > MaxRelativeOffsetInBlock)
{
// Need to flush relocation block as the current RVA is too far from base RVA
FlushRelocationBlock(builder, baseRVA, offsetsAndTypes);
offsetsAndTypes = null;
}
if (offsetsAndTypes == null)
{
// Create new relocation block
baseRVA = relocationRVA & -BaseRVAAlignment;
offsetsAndTypes = new List <ushort>();
}
ushort offsetAndType = (ushort)(((ushort)fileRelocType << RelocationTypeShift) | (relocationRVA - baseRVA));
offsetsAndTypes.Add(offsetAndType);
}
}
}
}
if (offsetsAndTypes != null)
{
FlushRelocationBlock(builder, baseRVA, offsetsAndTypes);
}
_relocationDirectoryEntry = new DirectoryEntry(sectionLocation.RelativeVirtualAddress, builder.Count);
return(builder);
}
/// <summary>
/// Add an ObjectData block to a given section.
/// </summary>
/// <param name="data">Block to add</param>
/// <param name="sectionIndex">Section index</param>
/// <param name="name">Node name to emit in the map file</param>
/// <param name="mapFileBuilder">Optional map file to emit</param>
public void AddObjectData(ObjectNode.ObjectData objectData, int sectionIndex, string name, MapFileBuilder mapFileBuilder)
{
Section section = _sections[sectionIndex];
// Calculate alignment padding - apparently ObjectDataBuilder can produce an alignment of 0
int alignedOffset = section.Content.Count;
if (objectData.Alignment > 1)
{
alignedOffset = (section.Content.Count + objectData.Alignment - 1) & -objectData.Alignment;
int padding = alignedOffset - section.Content.Count;
if (padding > 0)
{
if ((section.Characteristics & SectionCharacteristics.ContainsCode) != 0)
{
uint cp = _codePadding;
while (padding >= sizeof(uint))
{
section.Content.WriteUInt32(cp);
padding -= sizeof(uint);
}
if (padding >= 2)
{
section.Content.WriteUInt16(unchecked ((ushort)cp));
cp >>= 16;
}
if ((padding & 1) != 0)
{
section.Content.WriteByte(unchecked ((byte)cp));
}
}
else
{
section.Content.WriteBytes(0, padding);
}
}
}
if (mapFileBuilder != null)
{
MapFileNode node = new MapFileNode(sectionIndex, alignedOffset, objectData.Data.Length, name);
mapFileBuilder.AddNode(node);
if (objectData.Relocs != null)
{
foreach (Relocation reloc in objectData.Relocs)
{
RelocType fileReloc = Relocation.GetFileRelocationType(reloc.RelocType);
if (fileReloc != RelocType.IMAGE_REL_BASED_ABSOLUTE)
{
mapFileBuilder.AddRelocation(node, fileReloc);
}
}
}
}
section.Content.WriteBytes(objectData.Data);
if (objectData.DefinedSymbols != null)
{
foreach (ISymbolDefinitionNode symbol in objectData.DefinedSymbols)
{
if (mapFileBuilder != null)
{
Utf8StringBuilder sb = new Utf8StringBuilder();
symbol.AppendMangledName(GetNameMangler(), sb);
int sectionRelativeOffset = alignedOffset + symbol.Offset;
mapFileBuilder.AddSymbol(new MapFileSymbol(sectionIndex, sectionRelativeOffset, sb.ToString()));
}
_symbolMap.Add(symbol, new SymbolTarget(
sectionIndex: sectionIndex,
offset: alignedOffset + symbol.Offset,
size: objectData.Data.Length));
}
}
if (objectData.Relocs != null && objectData.Relocs.Length != 0)
{
section.PlacedObjectDataToRelocate.Add(new PlacedObjectData(alignedOffset, objectData));
}
}