[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, 44 insertions, 0 deletions

diff --git a/llvm/lib/Target/Nios2/MCTargetDesc/Nios2ELFObjectWriter.cpp b/llvm/lib/Target/Nios2/MCTargetDesc/Nios2ELFObjectWriter.cpp
new file mode 100644
index 00000000000..04f727ad390
--- /dev/null
+++ b/llvm/lib/Target/Nios2/MCTargetDesc/Nios2ELFObjectWriter.cpp
@@ -0,0 +1,44 @@
+//===-- Nios2ELFObjectWriter.cpp - Nios2 ELF Writer -----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MCTargetDesc/Nios2FixupKinds.h"
+#include "MCTargetDesc/Nios2MCExpr.h"
+#include "MCTargetDesc/Nios2MCTargetDesc.h"
+#include "llvm/MC/MCELFObjectWriter.h"
+#include "llvm/MC/MCObjectWriter.h"
+
+using namespace llvm;
+
+namespace {
+class Nios2ELFObjectWriter : public MCELFObjectTargetWriter {
+public:
+  Nios2ELFObjectWriter(uint8_t OSABI)
+      : MCELFObjectTargetWriter(false, OSABI, ELF::EM_ALTERA_NIOS2, false) {}
+
+  ~Nios2ELFObjectWriter() override;
+
+  unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
+                        const MCFixup &Fixup, bool IsPCRel) const override;
+};
+} // namespace
+
+Nios2ELFObjectWriter::~Nios2ELFObjectWriter() {}
+
+unsigned Nios2ELFObjectWriter::getRelocType(MCContext &Ctx,
+                                            const MCValue &Target,
+                                            const MCFixup &Fixup,
+                                            bool IsPCRel) const {
+  return 0;
+}
+
+std::unique_ptr<MCObjectWriter>
+llvm::createNios2ELFObjectWriter(raw_pwrite_stream &OS, uint8_t OSABI) {
+  auto MOTW = llvm::make_unique<Nios2ELFObjectWriter>(OSABI);
+  return createELFObjectWriter(std::move(MOTW), OS, true);
+}