private void AddCode(ElfFile file, AsmContext context)
{
if (context.CodeSection.VirtualSize > 0) {
file.Sections.Add(new ElfSection {
Name = file.Strings.SaveString(".text"),
Type = ElfSectionType.ProgBits,
Address = 0,
Flags = ElfSectionFlags.Alloc | ElfSectionFlags.Executable,
Size = (uint)context.CodeSection.BytesCount,
Align = 2,
Offset = (uint)file.Data.Position
});
file.Segments.Add(new ElfSegment {
Type = ElfSegmentType.Load,
Offset = (uint)file.Data.Position,
VirtualAddress = 0,
PhysicalAddress = 0,
FileSize = (uint)context.CodeSection.BytesCount,
MemorySize = (uint)context.CodeSection.VirtualSize,
Flags = ElfSegmentFlags.Executable | ElfSegmentFlags.Readable,
Align = 1
});
file.Data.Write(context.CodeSection.Content.ToArray(), 0, context.CodeSection.BytesCount);
}
}
public void Save(AsmContext context, Stream stream)
{
var file = new ElfFile();
var writer = new BinaryWriter(stream);
file.Sections.Add(new ElfSection());
AddCode(file, context);
AddData(file, context);
AddFlash(file, context);
AddDebugLine(file, context);
var sectionsStringsIndex = file.AddStringsSection();
const int headerSize = 0x34;
const int segmentsOffset = headerSize;
const int segmentEntrySize = 0x20;
var dataOffset = (uint)(segmentsOffset + file.Segments.Count * segmentEntrySize);
var sectionsOffset = dataOffset + file.Data.Length;
var header = new ElfHeader {
Identification = {
Magic = new[] { (char)0x7f, 'E', 'L', 'F' },
FileClass = ElfFileClass.Elf32,
DataType = ElfDataType.Lsb,
Version = 1,
},
Type = ElfType.Executable,
Machine = 0x53,
Version = 1,
Entry = 0x0,
ProgramHeaderOffset = segmentsOffset,
SectionHeaderOffset = (uint)sectionsOffset,
Flags = 0x84,
ElfHeaderSize = headerSize,
ProgramHeaderEntrySize = segmentEntrySize,
ProgramHeaderCount = (ushort)file.Segments.Count,
SectionHeaderEntrySize = 0x28,
SectionHeaderCount = (ushort)file.Sections.Count,
StringSectionIndex = (ushort)sectionsStringsIndex
};
writer.WriteElf32(header);
foreach (var segment in file.Segments) {
var cloned = segment;
cloned.Offset += dataOffset;
writer.WriteElf32(cloned);
}
writer.Write(file.Data.ToArray());
foreach (var section in file.Sections) {
var cloned = section;
if (section.Type != ElfSectionType.Null) {
cloned.Offset += dataOffset;
}
writer.WriteElf32(cloned);
}
}
private void AddDebugLine(ElfFile file, AsmContext context)
{
var mem = new MemoryStream();
var writer = new BinaryWriter(mem);
var hdr = new DebugLineHeader {
FileNames = new[]
{
new DebugLineFile {Name = "test.asm"},
new DebugLineFile {Name = "test2.asm"},
}
};
writer.WriteDwarf2(hdr);
if (mem.Length > 0) {
file.Sections.Add(new ElfSection {
Name = file.Strings.SaveString(".debug_line"),
Type = ElfSectionType.ProgBits,
Address = 0,
Flags = ElfSectionFlags.None,
Size = (uint)mem.Length,
Align = 1,
Offset = (uint)file.Data.Position
});
file.Data.Write(mem.ToArray(), 0, (int)mem.Length);
}
}