Add support for using MI bundles as bundle-locked groups on x86

lib/Target/X86/X86MCInstLower.cpp

 //===-- X86MCInstLower.cpp - Convert X86 MachineInstr to an MCInst --------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file contains code to lower X86 MachineInstrs to their corresponding
@@ skipping 989 matching lines @@
     CS << "]";
   CS.flush();
 
   return Comment;
 }
 
 void X86AsmPrinter::EmitInstruction(const MachineInstr *MI) {
   X86MCInstLower MCInstLowering(*MF, *this);
   const X86RegisterInfo *RI = MF->getSubtarget<X86Subtarget>().getRegisterInfo();
 
+  // @LOCALMOD-START
+  // MI Bundles are used to represent bundle-locked groups.
+  // MBB iterators skip bundles, so when we reach a bundle head, unpack it here.
+  if (MI->isBundle()) {
+    MachineBasicBlock::const_iterator MBBI(MI);
+    MachineBasicBlock::const_instr_iterator MII (MBBI.getInstrIterator());
+    ++MBBI;
+    OutStreamer.EmitBundleLock(false);
+    while (++MII != MBBI) {
+      EmitInstruction(MII);
+    }
+    OutStreamer.EmitBundleUnlock();
+    return;
+  }
+  // @LOCALMOD-END
+
   switch (MI->getOpcode()) {
   case TargetOpcode::DBG_VALUE:
     llvm_unreachable("Should be handled target independently");
 
   // Emit nothing here but a comment if we can.
   case X86::Int_MemBarrier:
     OutStreamer.emitRawComment("MEMBARRIER");
     return;
 
 
@@ skipping 295 matching lines @@
     // Then flush the shadow so that we fill with nops before the call, not
     // after it.
     SMShadowTracker.emitShadowPadding(OutStreamer, getSubtargetInfo());
     // Then emit the call
     OutStreamer.EmitInstruction(TmpInst, getSubtargetInfo());
     return;
   }
 
   EmitAndCountInstruction(TmpInst);
 }