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, 1 insertions, 2 deletions

diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
index 01b98ccf897..f558ca8d2d9 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
@@ -659,11 +659,10 @@ private:
                          uint64_t Offset) {
     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
         Name + "." + Twine(MappingSymbolCounter++)));
-    EmitLabel(Symbol, Loc, F);
+    EmitLabelAtPos(Symbol, Loc, F, Offset);
     Symbol->setType(ELF::STT_NOTYPE);
     Symbol->setBinding(ELF::STB_LOCAL);
     Symbol->setExternal(false);
-    Symbol->setOffset(Offset);
   }
 
   void EmitThumbFunc(MCSymbol *Func) override {