[Nios2] final infrastructure to provide compilation of a return from a function

This patch includes all missing functionality needed to provide first
compilation of a simple program that just returns from a function.
I've added a test case that checks for "ret" instruction printed in assembly
output.

Patch by Andrei Grischenko (andrei.l.grischenko@intel.com)
Differential revision: https://reviews.llvm.org/D39688

llvm-svn: 320035

1 files changed, 66 insertions, 0 deletions

diff --git a/llvm/lib/Target/Nios2/InstPrinter/Nios2InstPrinter.cpp b/llvm/lib/Target/Nios2/InstPrinter/Nios2InstPrinter.cpp
new file mode 100644
index 00000000000..de0a5f9e84e
--- /dev/null
+++ b/llvm/lib/Target/Nios2/InstPrinter/Nios2InstPrinter.cpp
@@ -0,0 +1,66 @@
+//===-- Nios2InstPrinter.cpp - Convert Nios2 MCInst to assembly syntax-----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This class prints an Nios2 MCInst to a .s file.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Nios2InstPrinter.h"
+
+#include "Nios2InstrInfo.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "asm-printer"
+
+#define PRINT_ALIAS_INSTR
+#include "Nios2GenAsmWriter.inc"
+
+void Nios2InstPrinter::printRegName(raw_ostream &OS, unsigned RegNo) const {
+  OS << getRegisterName(RegNo);
+}
+
+void Nios2InstPrinter::printInst(const MCInst *MI, raw_ostream &O,
+                                 StringRef Annot, const MCSubtargetInfo &STI) {
+  // Try to print any aliases first.
+  if (!printAliasInstr(MI, STI, O))
+    printInstruction(MI, STI, O);
+  printAnnotation(O, Annot);
+}
+
+void Nios2InstPrinter::printOperand(const MCInst *MI, int OpNo,
+                                    const MCSubtargetInfo &STI,
+                                    raw_ostream &O) {
+  const MCOperand &Op = MI->getOperand(OpNo);
+  if (Op.isReg()) {
+    printRegName(O, Op.getReg());
+    return;
+  }
+
+  if (Op.isImm()) {
+    O << Op.getImm();
+    return;
+  }
+
+  assert(Op.isExpr() && "unknown operand kind in printOperand");
+  Op.getExpr()->print(O, &MAI, true);
+}
+
+void Nios2InstPrinter::printMemOperand(const MCInst *MI, int opNum,
+                                       const MCSubtargetInfo &STI,
+                                       raw_ostream &O, const char *Modifier) {
+  // Load/Store memory operands -- imm($reg)
+  printOperand(MI, opNum + 1, STI, O);
+  O << "(";
+  printOperand(MI, opNum, STI, O);
+  O << ")";
+}