[PATCH] D95998: [Debug-Info] [NFC] use emitDwarfUnitLength to handle debug line section unit length field

[ChenZheng via Phabricator via llvm-commits]

shchenz updated this revision to Diff 322652.
shchenz added a comment.

1: split refactor of `emitDwarfUnitLength` to patch D96409 <https://reviews.llvm.org/D96409>


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D95998/new/

https://reviews.llvm.org/D95998

Files:
  llvm/lib/MC/MCDwarf.cpp


Index: llvm/lib/MC/MCDwarf.cpp
===================================================================
--- llvm/lib/MC/MCDwarf.cpp
+++ llvm/lib/MC/MCDwarf.cpp
@@ -476,21 +476,11 @@
 
   // Create a symbol for the end of the section (to be set when we get there).
   MCSymbol *LineEndSym = context.createTempSymbol();
-
-  unsigned UnitLengthBytes =
-      dwarf::getUnitLengthFieldByteSize(context.getDwarfFormat());
   unsigned OffsetSize = dwarf::getDwarfOffsetByteSize(context.getDwarfFormat());
 
-  if (context.getDwarfFormat() == dwarf::DWARF64)
-    // Emit DWARF64 mark.
-    MCOS->emitInt32(dwarf::DW_LENGTH_DWARF64);
-
-  // The length field does not include itself and, in case of the 64-bit DWARF
-  // format, the DWARF64 mark.
-  emitAbsValue(*MCOS,
-               makeEndMinusStartExpr(context, *LineStartSym, *LineEndSym,
-                                     UnitLengthBytes),
-               OffsetSize);
+  MCOS->emitDwarfUnitLength(LineEndSym, "unit length");
+  MCSymbol *SymWithoutUnitLength = context.createTempSymbol("debug_line_");
+  MCOS->emitLabel(SymWithoutUnitLength);
 
   // Next 2 bytes is the Version.
   unsigned LineTableVersion = context.getDwarfVersion();
@@ -498,7 +488,7 @@
 
   // Keep track of the bytes between the very start and where the header length
   // comes out.
-  unsigned PreHeaderLengthBytes = UnitLengthBytes + 2;
+  unsigned PreHeaderLengthBytes = 2;
 
   // In v5, we get address info next.
   if (LineTableVersion >= 5) {
@@ -513,7 +503,7 @@
   // Length of the prologue, is the next 4 bytes (8 bytes for DWARF64). This is
   // actually the length from after the length word, to the end of the prologue.
   emitAbsValue(*MCOS,
-               makeEndMinusStartExpr(context, *LineStartSym, *ProEndSym,
+               makeEndMinusStartExpr(context, *SymWithoutUnitLength, *ProEndSym,
                                      (PreHeaderLengthBytes + OffsetSize)),
                OffsetSize);
 


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