[Hexagon] Adding basic Hexagon ELF object emitter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221465 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/Hexagon/MCTargetDesc/HexagonELFObjectWriter.cpp

@@ -0,0 +1,62 @@
+//===-- HexagonELFObjectWriter.cpp - Hexagon Target Descriptions ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Hexagon.h"
+#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCELFObjectWriter.h"
+#include "llvm/Support/Debug.h"
+
+#define DEBUG_TYPE "hexagon-elf-writer"
+
+using namespace llvm;
+using namespace Hexagon;
+
+namespace {
+
+class HexagonELFObjectWriter : public MCELFObjectTargetWriter {
+private:
+  StringRef _CPU;
+
+public:
+  HexagonELFObjectWriter(uint8_t OSABI, StringRef CPU);
+
+  virtual unsigned GetRelocType(MCValue const &Target, MCFixup const &Fixup,
+                                bool IsPCRel) const override;
+};
+}
+
+HexagonELFObjectWriter::HexagonELFObjectWriter(uint8_t OSABI, StringRef CPU)
+    : MCELFObjectTargetWriter(/*Is64bit*/ false, OSABI, ELF::EM_HEXAGON,
+                              /*HasRelocationAddend*/ true),
+      _CPU(CPU) {}
+
+unsigned HexagonELFObjectWriter::GetRelocType(MCValue const &/*Target*/,
+                                              MCFixup const &Fixup,
+                                              bool IsPCRel) const {
+  unsigned Type = (unsigned)ELF::R_HEX_NONE;
+  llvm::MCFixupKind Kind = Fixup.getKind();
+
+  switch (Kind) {
+  default:
+    DEBUG(dbgs() << "unrecognized relocation " << Fixup.getKind() << "\n");
+    llvm_unreachable("Unimplemented Fixup kind!");
+    break;
+  case FK_Data_4:
+    Type = (IsPCRel) ? ELF::R_HEX_32_PCREL : ELF::R_HEX_32;
+    break;
+  }
+  return Type;
+}
+
+MCObjectWriter *llvm::createHexagonELFObjectWriter(raw_ostream &OS,
+                                                   uint8_t OSABI,
+                                                   StringRef CPU) {
+  MCELFObjectTargetWriter *MOTW = new HexagonELFObjectWriter(OSABI, CPU);
+  return createELFObjectWriter(MOTW, OS, /*IsLittleEndian*/ true);
+}