1 files changed, 83 insertions, 0 deletions
diff --git a/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp b/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp
new file mode 100644
index 0000000..87c8077
--- /dev/null
+++ b/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp
@@ -0,0 +1,83 @@
+//===-- BPFAsmBackend.cpp - BPF Assembler Backend -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MCTargetDesc/BPFMCTargetDesc.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCDirectives.h"
+#include "llvm/MC/MCELFObjectWriter.h"
+#include "llvm/MC/MCFixupKindInfo.h"
+#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+namespace {
+class BPFAsmBackend : public MCAsmBackend {
+public:
+  BPFAsmBackend() : MCAsmBackend() {}
+  ~BPFAsmBackend() override {}
+
+  void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
+                  uint64_t Value, bool IsPCRel) const override;
+
+  MCObjectWriter *createObjectWriter(raw_ostream &OS) const override;
+
+  // No instruction requires relaxation
+  bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
+                            const MCRelaxableFragment *DF,
+                            const MCAsmLayout &Layout) const override {
+    return false;
+  }
+
+  unsigned getNumFixupKinds() const override { return 1; }
+
+  bool mayNeedRelaxation(const MCInst &Inst) const override { return false; }
+
+  void relaxInstruction(const MCInst &Inst, MCInst &Res) const override {}
+
+  bool writeNopData(uint64_t Count, MCObjectWriter *OW) const override;
+};
+
+bool BPFAsmBackend::writeNopData(uint64_t Count, MCObjectWriter *OW) const {
+  if ((Count % 8) != 0)
+    return false;
+
+  for (uint64_t i = 0; i < Count; i += 8)
+    OW->Write64(0x15000000);
+
+  return true;
+}
+
+void BPFAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
+                               unsigned DataSize, uint64_t Value,
+                               bool IsPCRel) const {
+
+  if (Fixup.getKind() == FK_SecRel_4 || Fixup.getKind() == FK_SecRel_8) {
+    assert(Value == 0);
+    return;
+  }
+  assert(Fixup.getKind() == FK_PCRel_2);
+  *(uint16_t *)&Data[Fixup.getOffset() + 2] = (uint16_t)((Value - 8) / 8);
+}
+
+MCObjectWriter *BPFAsmBackend::createObjectWriter(raw_ostream &OS) const {
+  return createBPFELFObjectWriter(OS, 0);
+}
+}
+
+MCAsmBackend *llvm::createBPFAsmBackend(const Target &T,
+                                        const MCRegisterInfo &MRI, StringRef TT,
+                                        StringRef CPU) {
+  return new BPFAsmBackend();
+}