MC/Mach-O: Implement support for setting indirect symbol table offset in section header.

Also, create symbol data for LHS of assignment, to match 'as' symbol ordering better.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104033 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index f1dc349..e4ddf1a 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -216,6 +216,7 @@
 
 void MCMachOStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
   // FIXME: Lift context changes into super class.
+  Assembler.getOrCreateSymbolData(*Symbol);
   Symbol->setVariableValue(AddValueSymbols(Value));
 }