fix nullptr Mangler in LTOModule

[inglorion]

This should fix the problem in http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/2511/steps/check-llvm%20ubsan/logs/stdio

[pcc]

I think this is a functional change in that we will emit COFF linker flags in non-COFF objects. An easy fix would be to ask TT what the object format is.

Do you understand why there was a nullptr before?

[inglorion]

Good point on the functional change. I'll implement your suggestion to check TT. I don't know yet why there was a nullptr before; this is intended more as a temporary stopgap for until I figure that out.

[inglorion]

Only call getObjFileLoweringCOFF when we are actually generating for a target that has COFF - if not, we don't need to do anything here.

[pcc]

LGTM

lib/LTO/LTOModule.cpp

653

Nit: if (!TT.isOSBinFormatCOFF())

[inglorion]

if (!TT.isOSBinFormatCOFF())

lib/LTO/LTOModule.cpp

 // intended to be used by linker to optimize code at link time.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/LTO/legacy/LTOModule.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Bitcode/BitcodeReader.h"
 #include "llvm/CodeGen/Analysis.h"
+#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/Module.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCInstrInfo.h"
for (unsigned i = 0, e = LinkerOptions->getNumOperands(); i != e; ++i) {
       MDNode *MDOptions = cast<MDNode>(LinkerOptions->getOperand(i));
       for (unsigned ii = 0, ie = MDOptions->getNumOperands(); ii != ie; ++ii) {
         MDString *MDOption = cast<MDString>(MDOptions->getOperand(ii));
         OS << " " << MDOption->getString();
       }
     }
   }
 
-  // Globals
+  // Globals - we only need to do this for COFF.
+  const Triple TT(_target->getTargetTriple());
+  if (TT.getObjectFormat() != Triple::ObjectFormatType::COFF)
+    return;
+  Mangler M;
   for (const NameAndAttributes &Sym : _symbols) {
     if (!Sym.symbol)
       continue;
-    _target->getObjFileLowering()->emitLinkerFlagsForGlobal(OS, Sym.symbol);
+    emitLinkerFlagsForGlobalCOFF(OS, Sym.symbol, TT, M);
   }
 
   // Add other interesting metadata here.
 }