lto/addAsmGlobalSymbols: fast path when no module level asm is present

tools/lto/LTOModule.cpp

 //===-- LTOModule.cpp - LLVM Link Time Optimizer --------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the Link Time Optimization library. This library is
@@ skipping 597 matching lines @@
       for (unsigned i = Inst.getNumOperands(); i--; )
         if (Inst.getOperand(i).isExpr())
           AddValueSymbols(Inst.getOperand(i).getExpr());
     }
     virtual void Finish() {}
   };
 }
 
 bool LTOModule::addAsmGlobalSymbols(MCContext &Context) {
   const std::string &inlineAsm = _module->getModuleInlineAsm();
+  if (inlineAsm.empty())
+    return false;
 
   OwningPtr<RecordStreamer> Streamer(new RecordStreamer(Context));
   MemoryBuffer *Buffer = MemoryBuffer::getMemBuffer(inlineAsm);
   SourceMgr SrcMgr;
   SrcMgr.AddNewSourceBuffer(Buffer, SMLoc());
   OwningPtr<MCAsmParser> Parser(createMCAsmParser(SrcMgr,
                                                   Context, *Streamer,
                                                   *_target->getMCAsmInfo()));
   OwningPtr<MCSubtargetInfo> STI(_target->getTarget().
                       createMCSubtargetInfo(_target->getTargetTriple(),
@@ skipping 93 matching lines @@
   else
     return lto_symbol_attributes(0);
 }
 
 const char *LTOModule::getSymbolName(uint32_t index) {
   if (index < _symbols.size())
     return _symbols[index].name;
   else
     return NULL;
 }