[Debug-Info][NFC] move emitDwarfUnitLength to MCStreamer class

We may need to do some customization for DWARF unit length in DWARF
section headers for some targets for some code generation path.

For example, for XCOFF in assembly path, AIX assembler does not require
the debug section containing its debug unit length in the header.

Move emitDwarfUnitLength to MCStreamer class so that we can do
customization in different Streamers

Reviewed By: ikudrin

Differential Revision: https://reviews.llvm.org/D95932

1 files changed, 23 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index 4b5ae3c..4f2ec51 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -991,6 +991,29 @@ void MCStreamer::Finish(SMLoc EndLoc) {
   finishImpl();
 }
 
+void MCStreamer::maybeEmitDwarf64Mark() {
+  if (Context.getDwarfFormat() != dwarf::DWARF64)
+    return;
+  AddComment("DWARF64 Mark");
+  emitInt32(dwarf::DW_LENGTH_DWARF64);
+}
+
+void MCStreamer::emitDwarfUnitLength(uint64_t Length, const Twine &Comment) {
+  assert(Context.getDwarfFormat() == dwarf::DWARF64 ||
+         Length <= dwarf::DW_LENGTH_lo_reserved);
+  maybeEmitDwarf64Mark();
+  AddComment(Comment);
+  emitIntValue(Length, dwarf::getDwarfOffsetByteSize(Context.getDwarfFormat()));
+}
+
+void MCStreamer::emitDwarfUnitLength(const MCSymbol *Hi, const MCSymbol *Lo,
+                                     const Twine &Comment) {
+  maybeEmitDwarf64Mark();
+  AddComment(Comment);
+  emitAbsoluteSymbolDiff(
+      Hi, Lo, dwarf::getDwarfOffsetByteSize(Context.getDwarfFormat()));
+}
+
 void MCStreamer::emitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
   visitUsedExpr(*Value);
   Symbol->setVariableValue(Value);