[llvm] [llvm-objcopy] Support SREC output format (PR #75874)

[James Henderson via llvm-commits]

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@@ -2813,6 +2813,244 @@ Error IHexWriter::finalize() {
   return Error::success();
 }
 
+Error SRECSectionWriterBase::visit(const StringTableSection &Sec) {
+  // Check that sizer has already done its work
+  assert(Sec.Size == Sec.StrTabBuilder.getSize());
+  // we don't need to write anything here the real writer has already done it.
+  return Error::success();
+}
+
+Error SRECSectionWriterBase::visit(const Section &Sec) {
+  writeSection(Sec, Sec.Contents);
+  return Error::success();
+}
+
+Error SRECSectionWriterBase::visit(const OwnedDataSection &Sec) {
+  writeSection(Sec, Sec.Data);
+  return Error::success();
+}
+
+Error SRECSectionWriterBase::visit(const DynamicRelocationSection &Sec) {
+  writeSection(Sec, Sec.Contents);
+  return Error::success();
+}
+
+void SRECSectionWriter::writeRecord(SRecord &Record, uint64_t Off) {
+  SRecLineData Data = Record.toString();
+  memcpy(Out.getBufferStart() + Off, Data.data(), Data.size());
+}
+
+void SRECSectionWriter::writeRecords(uint32_t Entry) {
+  Type = std::max(Type, SRecord::getType(Entry));
+  uint64_t Off = HeaderSize;
+  for (SRecord &Record : Records) {
+    Record.Type = Type;
+    writeRecord(Record, Off);
+    Off += Record.getSize();
+  }
+  Offset = Off;
+}
+
+void SRECSectionWriterBase::writeRecords(uint32_t Entry) {
+  // The ELF header could contain an entry point outside of the sections we have
+  // seen that does not fit the current record Type
+  Type = std::max(Type, SRecord::getType(Entry));
+  uint64_t Off = HeaderSize;
+  for (SRecord &Record : Records) {
+    Record.Type = Type;
+    Off += Record.getSize();
+  }
+  Offset = Off;
+}
+
+void SRECSectionWriterBase::writeSection(const SectionBase &S,
+                                         ArrayRef<uint8_t> Data) {
+  const uint32_t ChunkSize = 16;
+  uint32_t Address = sectionPhysicalAddr(&S);
+  uint32_t EndAddr = Address + S.Size - 1;
+  Type = std::max(SRecord::getType(EndAddr), Type);
+  while (!Data.empty()) {
+    uint64_t DataSize = std::min<uint64_t>(Data.size(), ChunkSize);
+    SRecord Record{Type, Address, Data.take_front(DataSize)};
+    Records.push_back(Record);
+    Data = Data.drop_front(DataSize);
+    Address += DataSize;
+  }
+}
+
+Error SRECSectionWriter::visit(const StringTableSection &Sec) {
+  assert(Sec.Size == Sec.StrTabBuilder.getSize());
+  std::vector<uint8_t> Data(Sec.Size);
+  Sec.StrTabBuilder.write(Data.data());
+  writeSection(Sec, Data);
+  return Error::success();
+}
+
+SRecLineData SRecord::toString() const {
+  SRecLineData Line(getSize());
+  auto *Iter = Line.begin();
+  *Iter++ = 'S';
+  *Iter++ = '0' + Type;
+  // write 1 byte (2 hex characters) record count
+  Iter = toHexStr(getCount(), Iter, 2);
+  // write the address field with length depending on record type
+  Iter = toHexStr(Address, Iter, getAddressSize());
+  // write data byte by byte
+  for (uint8_t X : Data)
+    Iter = toHexStr(X, Iter, 2);
+  // write the 1 byte checksum
+  Iter = toHexStr(getChecksum(), Iter, 2);
+  *Iter++ = '\r';
+  *Iter++ = '\n';
+  assert(Iter == Line.end());
+  return Line;
+}
+
+uint8_t SRecord::getChecksum() const {
+  uint32_t Sum = getCount();
+  Sum += (Address >> 24) & 0xFF;
+  Sum += (Address >> 16) & 0xFF;
+  Sum += (Address >> 8) & 0xFF;
+  Sum += Address & 0xFF;
+  for (uint8_t Byte : Data)
+    Sum += Byte;
+  return 0xFF - (Sum & 0xFF);
+}
+
+size_t SRecord::getSize() const {
+  // 2 characters for type, count, checksum, CRLF
----------------
jh7370 wrote:

Nit: comment style.

https://github.com/llvm/llvm-project/pull/75874