[patchpoint] Add support for symbolic patchpoint targets to SelectionDAG and the

X86 backend.

The code generated for symbolic targets is identical to the code generated for
constant targets, except that a relocation is emitted to fix up the actual
target address at link-time. This allows IR and object files containing
patchpoints to be cached across JIT-invocations where the target address may
change.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235483 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCInstBuilder.h

@@ -58,6 +58,12 @@ public:
     return *this;
   }
 
+  /// \brief Add an operand.
+  MCInstBuilder &addOperand(const MCOperand &Op) {
+    Inst.addOperand(Op);
+    return *this;
+  }
+
   operator MCInst&() {
     return Inst;
   }