1 files changed, 151 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp b/contrib/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp
new file mode 100644
index 0000000..e901c6c
--- /dev/null
+++ b/contrib/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp
@@ -0,0 +1,151 @@
+//===-- SystemZMCAsmBackend.cpp - SystemZ 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/SystemZMCTargetDesc.h"
+#include "MCTargetDesc/SystemZMCFixups.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCELFObjectWriter.h"
+#include "llvm/MC/MCFixupKindInfo.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCObjectWriter.h"
+
+using namespace llvm;
+
+// Value is a fully-resolved relocation value: Symbol + Addend [- Pivot].
+// Return the bits that should be installed in a relocation field for
+// fixup kind Kind.
+static uint64_t extractBitsForFixup(MCFixupKind Kind, uint64_t Value) {
+  if (Kind < FirstTargetFixupKind)
+    return Value;
+
+  switch (unsigned(Kind)) {
+  case SystemZ::FK_390_PC16DBL:
+  case SystemZ::FK_390_PC32DBL:
+  case SystemZ::FK_390_PLT16DBL:
+  case SystemZ::FK_390_PLT32DBL:
+    return (int64_t)Value / 2;
+  }
+
+  llvm_unreachable("Unknown fixup kind!");
+}
+
+// If Opcode can be relaxed, return the relaxed form, otherwise return 0.
+static unsigned getRelaxedOpcode(unsigned Opcode) {
+  switch (Opcode) {
+  case SystemZ::BRC:  return SystemZ::BRCL;
+  case SystemZ::J:    return SystemZ::JG;
+  case SystemZ::BRAS: return SystemZ::BRASL;
+  }
+  return 0;
+}
+
+namespace {
+class SystemZMCAsmBackend : public MCAsmBackend {
+  uint8_t OSABI;
+public:
+  SystemZMCAsmBackend(uint8_t osABI)
+    : OSABI(osABI) {}
+
+  // Override MCAsmBackend
+  virtual unsigned getNumFixupKinds() const LLVM_OVERRIDE {
+    return SystemZ::NumTargetFixupKinds;
+  }
+  virtual const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const
+    LLVM_OVERRIDE;
+  virtual void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
+                          uint64_t Value) const LLVM_OVERRIDE;
+  virtual bool mayNeedRelaxation(const MCInst &Inst) const LLVM_OVERRIDE;
+  virtual bool fixupNeedsRelaxation(const MCFixup &Fixup,
+                                    uint64_t Value,
+                                    const MCRelaxableFragment *Fragment,
+                                    const MCAsmLayout &Layout) const
+    LLVM_OVERRIDE;
+  virtual void relaxInstruction(const MCInst &Inst,
+                                MCInst &Res) const LLVM_OVERRIDE;
+  virtual bool writeNopData(uint64_t Count,
+                            MCObjectWriter *OW) const LLVM_OVERRIDE;
+  virtual MCObjectWriter *createObjectWriter(raw_ostream &OS) const
+    LLVM_OVERRIDE {
+    return createSystemZObjectWriter(OS, OSABI);
+  }
+  virtual bool doesSectionRequireSymbols(const MCSection &Section) const
+    LLVM_OVERRIDE {
+    return false;
+  }
+};
+} // end anonymous namespace
+
+const MCFixupKindInfo &
+SystemZMCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
+  const static MCFixupKindInfo Infos[SystemZ::NumTargetFixupKinds] = {
+    { "FK_390_PC16DBL",  0, 16, MCFixupKindInfo::FKF_IsPCRel },
+    { "FK_390_PC32DBL",  0, 32, MCFixupKindInfo::FKF_IsPCRel },
+    { "FK_390_PLT16DBL", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
+    { "FK_390_PLT32DBL", 0, 32, MCFixupKindInfo::FKF_IsPCRel }
+  };
+
+  if (Kind < FirstTargetFixupKind)
+    return MCAsmBackend::getFixupKindInfo(Kind);
+
+  assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
+         "Invalid kind!");
+  return Infos[Kind - FirstTargetFixupKind];
+}
+
+void SystemZMCAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
+                                     unsigned DataSize, uint64_t Value) const {
+  MCFixupKind Kind = Fixup.getKind();
+  unsigned Offset = Fixup.getOffset();
+  unsigned Size = (getFixupKindInfo(Kind).TargetSize + 7) / 8;
+
+  assert(Offset + Size <= DataSize && "Invalid fixup offset!");
+
+  // Big-endian insertion of Size bytes.
+  Value = extractBitsForFixup(Kind, Value);
+  unsigned ShiftValue = (Size * 8) - 8;
+  for (unsigned I = 0; I != Size; ++I) {
+    Data[Offset + I] |= uint8_t(Value >> ShiftValue);
+    ShiftValue -= 8;
+  }
+}
+
+bool SystemZMCAsmBackend::mayNeedRelaxation(const MCInst &Inst) const {
+  return getRelaxedOpcode(Inst.getOpcode()) != 0;
+}
+
+bool
+SystemZMCAsmBackend::fixupNeedsRelaxation(const MCFixup &Fixup,
+                                          uint64_t Value,
+                                          const MCRelaxableFragment *Fragment,
+                                          const MCAsmLayout &Layout) const {
+  // At the moment we just need to relax 16-bit fields to wider fields.
+  Value = extractBitsForFixup(Fixup.getKind(), Value);
+  return (int16_t)Value != (int64_t)Value;
+}
+
+void SystemZMCAsmBackend::relaxInstruction(const MCInst &Inst,
+                                           MCInst &Res) const {
+  unsigned Opcode = getRelaxedOpcode(Inst.getOpcode());
+  assert(Opcode && "Unexpected insn to relax");
+  Res = Inst;
+  Res.setOpcode(Opcode);
+}
+
+bool SystemZMCAsmBackend::writeNopData(uint64_t Count,
+                                       MCObjectWriter *OW) const {
+  for (uint64_t I = 0; I != Count; ++I)
+    OW->Write8(7);
+  return true;
+}
+
+MCAsmBackend *llvm::createSystemZMCAsmBackend(const Target &T, StringRef TT,
+                                              StringRef CPU) {
+  uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(Triple(TT).getOS());
+  return new SystemZMCAsmBackend(OSABI);
+}