MCObjectStreamer: assign MCSymbols in the dummy fragment to offset 0.

In MCObjectStreamer, when there is no current fragment, initially
symbols are created in a "pending" state and assigned to a dummy
empty fragment.

Previously, they were not being assigned an offset, and thus
evaluateAbsolute would fail if trying to evaluate an expression 'a -
b', where both 'a' and 'b' were in this pending state.

Also slightly refactored the EmitLabel overload which takes an
MCFragment for clarity.

Fixes: https://llvm.org/PR41825

Differential Revision: https://reviews.llvm.org/D70062

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/MC/MCELFStreamer.cpp b/llvm/lib/MC/MCELFStreamer.cpp
index fa2133078bf..c2e2beb23cb 100644
--- a/llvm/lib/MC/MCELFStreamer.cpp
+++ b/llvm/lib/MC/MCELFStreamer.cpp
@@ -106,9 +106,10 @@ void MCELFStreamer::EmitLabel(MCSymbol *S, SMLoc Loc) {
     Symbol->setType(ELF::STT_TLS);
 }
 
-void MCELFStreamer::EmitLabel(MCSymbol *S, SMLoc Loc, MCFragment *F) {
+void MCELFStreamer::EmitLabelAtPos(MCSymbol *S, SMLoc Loc, MCFragment *F,
+                                   uint64_t Offset) {
   auto *Symbol = cast<MCSymbolELF>(S);
-  MCObjectStreamer::EmitLabel(Symbol, Loc, F);
+  MCObjectStreamer::EmitLabelAtPos(Symbol, Loc, F, Offset);
 
   const MCSectionELF &Section =
       static_cast<const MCSectionELF &>(*getCurrentSectionOnly());