[llvm] [SystemZ][z/OS] yaml2obj for header and end records (PR #73859)

[James Henderson via llvm-commits]

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@@ -0,0 +1,292 @@
+//===- yaml2goff - Convert YAML to a GOFF object file ---------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// The GOFF component of yaml2obj.
+///
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/IndexedMap.h"
+#include "llvm/ObjectYAML/ObjectYAML.h"
+#include "llvm/ObjectYAML/yaml2obj.h"
+#include "llvm/Support/ConvertEBCDIC.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+namespace {
+
+// Common flag values on records.
+enum {
+  // Flag: This record is continued.
+  Rec_Continued = 1,
+
+  // Flag: This record is a continuation.
+  Rec_Continuation = 1 << (8 - 6 - 1),
+};
+
+template <typename ValueType> struct BinaryBeImpl {
+  ValueType Value;
+  BinaryBeImpl(ValueType V) : Value(V) {}
+};
+
+template <typename ValueType>
+raw_ostream &operator<<(raw_ostream &OS, const BinaryBeImpl<ValueType> &BBE) {
+  char Buffer[sizeof(BBE.Value)];
+  support::endian::write<ValueType, llvm::endianness::big, support::unaligned>(
+      Buffer, BBE.Value);
+  OS.write(Buffer, sizeof(BBE.Value));
+  return OS;
+}
+
+template <typename ValueType> BinaryBeImpl<ValueType> binaryBe(ValueType V) {
+  return BinaryBeImpl<ValueType>(V);
+}
+
+struct ZerosImpl {
+  size_t NumBytes;
+};
+
+raw_ostream &operator<<(raw_ostream &OS, const ZerosImpl &Z) {
+  OS.write_zeros(Z.NumBytes);
+  return OS;
+}
+
+ZerosImpl zeros(const size_t NumBytes) { return ZerosImpl{NumBytes}; }
+
+// The GOFFOstream is responsible to write the data into the fixed physical
+// records of the format. A user of this class announces the start of a new
+// logical record and the size of its payload. While writing the payload, the
+// physical records are created for the data. Possible fill bytes at the end of
+// a physical record are written automatically.
+class GOFFOstream : public raw_ostream {
+public:
+  explicit GOFFOstream(raw_ostream &OS)
+      : OS(OS), LogicalRecords(0), RemainingSize(0), NewLogicalRecord(false) {
+    SetBufferSize(GOFF::PayloadLength);
+  }
+
+  ~GOFFOstream() { finalize(); }
+
+  void makeNewRecord(GOFF::RecordType Type, size_t Size);
+
+  void finalize() { fillRecord(); }
+
+  uint32_t logicalRecords() { return LogicalRecords; }
+
+private:
+  /// The underlying raw_ostream.
+  raw_ostream &OS;
+
+  /// The number of logical records emitted so far.
+  uint32_t LogicalRecords;
+
+  /// The remaining size of this logical record, including fill
+  /// bytes.
+  size_t RemainingSize;
+
+  /// The type of the current (logical) record.
+  GOFF::RecordType CurrentType;
+
+  /// Signals start of new record.
+  bool NewLogicalRecord;
+
+  // Return the number of bytes left to write until next physical record.
----------------
jh7370 wrote:

You've got a weird mixture of doxygen and regular comments. Is there a reason?

https://github.com/llvm/llvm-project/pull/73859