[Stackmap] Add AnyReg calling convention support for patchpoint intrinsic.

The idea of the AnyReg Calling Convention is to provide the call arguments in
registers, but not to force them to be placed in a paticular order into a
specified set of registers. Instead it is up tp the register allocator to assign
any register as it sees fit. The same applies to the return value (if
applicable).

Differential Revision: http://llvm-reviews.chandlerc.com/D2009

Reviewed by Andy

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194293 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/StackMaps.h

@@ -50,10 +50,12 @@ public:
   /// This should be called by the MC lowering code _immediately_ before
   /// lowering the MI to an MCInst. It records where the operands for the
   /// instruction are stored, and outputs a label to record the offset of
-  /// the call from the start of the text section.
+  /// the call from the start of the text section. In special cases (e.g. AnyReg
+  /// calling convention) the return register is also recorded if requested.
   void recordStackMap(const MachineInstr &MI, uint32_t ID,
                       MachineInstr::const_mop_iterator MOI,
-                      MachineInstr::const_mop_iterator MOE);
+                      MachineInstr::const_mop_iterator MOE,
+                      bool recordResult = false);
 
   /// If there is any stack map data, create a stack map section and serialize
   /// the map info into it. This clears the stack map data structures