[NVPTX] Start conversion to MC infrastructure

This change converts the NVPTX target to use the MC infrastructure
instead of directly emitting MachineInstr instances. This brings
the target more up-to-date with LLVM TOT, and should fix PR15175
and PR15958 (libNVPTXInstPrinter is empty) as a side-effect.

llvm-svn: 187798
diff --git a/llvm/lib/Target/NVPTX/NVPTXMCExpr.cpp b/llvm/lib/Target/NVPTX/NVPTXMCExpr.cpp
new file mode 100644
index 0000000..ca24764
--- /dev/null
+++ b/llvm/lib/Target/NVPTX/NVPTXMCExpr.cpp
@@ -0,0 +1,46 @@
+//===-- NVPTXMCExpr.cpp - NVPTX specific MC expression classes ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "nvptx-mcexpr"
+#include "NVPTXMCExpr.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCContext.h"
+using namespace llvm;
+
+const NVPTXFloatMCExpr*
+NVPTXFloatMCExpr::Create(VariantKind Kind, APFloat Flt, MCContext &Ctx) {
+  return new (Ctx) NVPTXFloatMCExpr(Kind, Flt);
+}
+
+void NVPTXFloatMCExpr::PrintImpl(raw_ostream &OS) const {
+  bool Ignored;
+  unsigned NumHex;
+  APFloat APF = getAPFloat();
+
+  switch (Kind) {
+  default: llvm_unreachable("Invalid kind!");
+  case VK_NVPTX_SINGLE_PREC_FLOAT:
+    OS << "0f";
+    NumHex = 8;
+    APF.convert(APFloat::IEEEsingle, APFloat::rmNearestTiesToEven, &Ignored);
+    break;
+  case VK_NVPTX_DOUBLE_PREC_FLOAT:
+    OS << "0d";
+    NumHex = 16;
+    APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, &Ignored);
+    break;
+  }
+
+  APInt API = APF.bitcastToAPInt();
+  std::string HexStr(utohexstr(API.getZExtValue()));
+  if (HexStr.length() < NumHex)
+    OS << std::string(NumHex - HexStr.length(), '0');
+  OS << utohexstr(API.getZExtValue());
+}