[llvm-branch-commits] [llvm] [HLSL] Refactor Offset calculation while writing Root Signatures. (PR #128577)

[Damyan Pepper via llvm-branch-commits]

================
@@ -12,44 +12,59 @@
 using namespace llvm;
 using namespace llvm::mcdxbc;
 
+void setRewrite(raw_ostream &Stream, uint32_t &Offset) {
+  const uint32_t DummyValue = std::numeric_limits<uint32_t>::max();
+  Offset = Stream.tell();
+  support::endian::write(Stream, DummyValue, llvm::endianness::little);
+}
+
+void rewriteOffset(buffer_ostream &Stream, uint32_t Offset) {
+  uint32_t Value = Stream.tell();
+  auto *InsertPoint = &Stream.buffer()[Offset];
+  support::endian::write(InsertPoint, Value, llvm::endianness::little);
+}
+
 void RootSignatureDesc::write(raw_ostream &OS) const {
-  // Root signature header in dxcontainer has 6 uint_32t values.
-  const uint32_t HeaderSize = 24;
-  const uint32_t ParameterByteSize = Parameters.size_in_bytes();
-  const uint32_t NumParametes = Parameters.size();
+  buffer_ostream Writer(OS);
----------------
damyanp wrote:

Not convinced "Writer" is an appropriate name now.  BOS?  BS?

```suggestion
  buffer_ostream BOS(OS);
```

https://github.com/llvm/llvm-project/pull/128577