Add R600 backend

A new backend supporting AMD GPUs: Radeon HD2XXX - HD7XXX

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169915 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 292 insertions, 0 deletions

diff --git a/lib/Target/R600/MCTargetDesc/SIMCCodeEmitter.cpp b/lib/Target/R600/MCTargetDesc/SIMCCodeEmitter.cpp
new file mode 100644
index 0000000000..7f271d1c45
--- /dev/null
+++ b/lib/Target/R600/MCTargetDesc/SIMCCodeEmitter.cpp
@@ -0,0 +1,292 @@
+//===-- SIMCCodeEmitter.cpp - SI Code Emitter -------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+/// \file
+/// \brief The SI code emitter produces machine code that can be executed
+/// directly on the GPU device.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MCTargetDesc/AMDGPUMCTargetDesc.h"
+#include "MCTargetDesc/AMDGPUMCCodeEmitter.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/Support/raw_ostream.h"
+
+#define VGPR_BIT(src_idx) (1ULL << (9 * src_idx - 1))
+#define SI_INSTR_FLAGS_ENCODING_MASK 0xf
+
+// These must be kept in sync with SIInstructions.td and also the
+// InstrEncodingInfo array in SIInstrInfo.cpp.
+//
+// NOTE: This enum is only used to identify the encoding type within LLVM,
+// the actual encoding type that is part of the instruction format is different
+namespace SIInstrEncodingType {
+  enum Encoding {
+    EXP = 0,
+    LDS = 1,
+    MIMG = 2,
+    MTBUF = 3,
+    MUBUF = 4,
+    SMRD = 5,
+    SOP1 = 6,
+    SOP2 = 7,
+    SOPC = 8,
+    SOPK = 9,
+    SOPP = 10,
+    VINTRP = 11,
+    VOP1 = 12,
+    VOP2 = 13,
+    VOP3 = 14,
+    VOPC = 15
+  };
+}
+
+using namespace llvm;
+
+namespace {
+class SIMCCodeEmitter : public  AMDGPUMCCodeEmitter {
+  SIMCCodeEmitter(const SIMCCodeEmitter &); // DO NOT IMPLEMENT
+  void operator=(const SIMCCodeEmitter &); // DO NOT IMPLEMENT
+  const MCInstrInfo &MCII;
+  const MCRegisterInfo &MRI;
+  const MCSubtargetInfo &STI;
+  MCContext &Ctx;
+
+public:
+  SIMCCodeEmitter(const MCInstrInfo &mcii, const MCRegisterInfo &mri,
+                  const MCSubtargetInfo &sti, MCContext &ctx)
+    : MCII(mcii), MRI(mri), STI(sti), Ctx(ctx) { }
+
+  ~SIMCCodeEmitter() { }
+
+  /// \breif Encode the instruction and write it to the OS.
+  virtual void EncodeInstruction(const MCInst &MI, raw_ostream &OS,
+                         SmallVectorImpl<MCFixup> &Fixups) const;
+
+  /// \returns the encoding for an MCOperand.
+  virtual uint64_t getMachineOpValue(const MCInst &MI, const MCOperand &MO,
+                                     SmallVectorImpl<MCFixup> &Fixups) const;
+
+public:
+
+  /// \brief Encode a sequence of registers with the correct alignment.
+  unsigned GPRAlign(const MCInst &MI, unsigned OpNo, unsigned shift) const;
+
+  /// \brief Encoding for when 2 consecutive registers are used
+  virtual unsigned GPR2AlignEncode(const MCInst &MI, unsigned OpNo,
+                                   SmallVectorImpl<MCFixup> &Fixup) const;
+
+  /// \brief Encoding for when 4 consectuive registers are used
+  virtual unsigned GPR4AlignEncode(const MCInst &MI, unsigned OpNo,
+                                   SmallVectorImpl<MCFixup> &Fixup) const;
+
+  /// \brief Encoding for SMRD indexed loads
+  virtual uint32_t SMRDmemriEncode(const MCInst &MI, unsigned OpNo,
+                                   SmallVectorImpl<MCFixup> &Fixup) const;
+
+  /// \brief Post-Encoder method for VOP instructions
+  virtual uint64_t VOPPostEncode(const MCInst &MI, uint64_t Value) const;
+
+private:
+
+  /// \returns this SIInstrEncodingType for this instruction.
+  unsigned getEncodingType(const MCInst &MI) const;
+
+  /// \brief Get then size in bytes of this instructions encoding.
+  unsigned getEncodingBytes(const MCInst &MI) const;
+
+  /// \returns the hardware encoding for a register
+  unsigned getRegBinaryCode(unsigned reg) const;
+
+  /// \brief Generated function that returns the hardware encoding for
+  /// a register
+  unsigned getHWRegNum(unsigned reg) const;
+
+};
+
+} // End anonymous namespace
+
+MCCodeEmitter *llvm::createSIMCCodeEmitter(const MCInstrInfo &MCII,
+                                           const MCRegisterInfo &MRI,
+                                           const MCSubtargetInfo &STI,
+                                           MCContext &Ctx) {
+  return new SIMCCodeEmitter(MCII, MRI, STI, Ctx);
+}
+
+void SIMCCodeEmitter::EncodeInstruction(const MCInst &MI, raw_ostream &OS,
+                                       SmallVectorImpl<MCFixup> &Fixups) const {
+  uint64_t Encoding = getBinaryCodeForInstr(MI, Fixups);
+  unsigned bytes = getEncodingBytes(MI);
+  for (unsigned i = 0; i < bytes; i++) {
+    OS.write((uint8_t) ((Encoding >> (8 * i)) & 0xff));
+  }
+}
+
+uint64_t SIMCCodeEmitter::getMachineOpValue(const MCInst &MI,
+                                            const MCOperand &MO,
+                                       SmallVectorImpl<MCFixup> &Fixups) const {
+  if (MO.isReg()) {
+    return getRegBinaryCode(MO.getReg());
+  } else if (MO.isImm()) {
+    return MO.getImm();
+  } else if (MO.isFPImm()) {
+    // XXX: Not all instructions can use inline literals
+    // XXX: We should make sure this is a 32-bit constant
+    union {
+      float F;
+      uint32_t I;
+    } Imm;
+    Imm.F = MO.getFPImm();
+    return Imm.I;
+  } else{
+    llvm_unreachable("Encoding of this operand type is not supported yet.");
+  }
+  return 0;
+}
+
+//===----------------------------------------------------------------------===//
+// Custom Operand Encodings
+//===----------------------------------------------------------------------===//
+
+unsigned SIMCCodeEmitter::GPRAlign(const MCInst &MI, unsigned OpNo,
+                                   unsigned shift) const {
+  unsigned regCode = getRegBinaryCode(MI.getOperand(OpNo).getReg());
+  return regCode >> shift;
+  return 0;
+}
+unsigned SIMCCodeEmitter::GPR2AlignEncode(const MCInst &MI,
+                                          unsigned OpNo ,
+                                        SmallVectorImpl<MCFixup> &Fixup) const {
+  return GPRAlign(MI, OpNo, 1);
+}
+
+unsigned SIMCCodeEmitter::GPR4AlignEncode(const MCInst &MI,
+                                          unsigned OpNo,
+                                        SmallVectorImpl<MCFixup> &Fixup) const {
+  return GPRAlign(MI, OpNo, 2);
+}
+
+#define SMRD_OFFSET_MASK 0xff
+#define SMRD_IMM_SHIFT 8
+#define SMRD_SBASE_MASK 0x3f
+#define SMRD_SBASE_SHIFT 9
+/// This function is responsibe for encoding the offset
+/// and the base ptr for SMRD instructions it should return a bit string in
+/// this format:
+///
+/// OFFSET = bits{7-0}
+/// IMM    = bits{8}
+/// SBASE  = bits{14-9}
+///
+uint32_t SIMCCodeEmitter::SMRDmemriEncode(const MCInst &MI, unsigned OpNo,
+                                        SmallVectorImpl<MCFixup> &Fixup) const {
+  uint32_t Encoding;
+
+  const MCOperand &OffsetOp = MI.getOperand(OpNo + 1);
+
+  //XXX: Use this function for SMRD loads with register offsets
+  assert(OffsetOp.isImm());
+
+  Encoding =
+      (getMachineOpValue(MI, OffsetOp, Fixup) & SMRD_OFFSET_MASK)
+    | (1 << SMRD_IMM_SHIFT) //XXX If the Offset is a register we shouldn't set this bit
+    | ((GPR2AlignEncode(MI, OpNo, Fixup) & SMRD_SBASE_MASK) << SMRD_SBASE_SHIFT)
+    ;
+
+  return Encoding;
+}
+
+//===----------------------------------------------------------------------===//
+// Post Encoder Callbacks
+//===----------------------------------------------------------------------===//
+
+uint64_t SIMCCodeEmitter::VOPPostEncode(const MCInst &MI, uint64_t Value) const{
+  unsigned encodingType = getEncodingType(MI);
+  unsigned numSrcOps;
+  unsigned vgprBitOffset;
+
+  if (encodingType == SIInstrEncodingType::VOP3) {
+    numSrcOps = 3;
+    vgprBitOffset = 32;
+  } else {
+    numSrcOps = 1;
+    vgprBitOffset = 0;
+  }
+
+  // Add one to skip over the destination reg operand.
+  for (unsigned opIdx = 1; opIdx < numSrcOps + 1; opIdx++) {
+    const MCOperand &MO = MI.getOperand(opIdx);
+    if (MO.isReg()) {
+      unsigned reg = MI.getOperand(opIdx).getReg();
+      if (AMDGPUMCRegisterClasses[AMDGPU::VReg_32RegClassID].contains(reg) ||
+          AMDGPUMCRegisterClasses[AMDGPU::VReg_64RegClassID].contains(reg)) {
+        Value |= (VGPR_BIT(opIdx)) << vgprBitOffset;
+      }
+    } else if (MO.isFPImm()) {
+      union {
+        float f;
+        uint32_t i;
+      } Imm;
+      // XXX: Not all instructions can use inline literals
+      // XXX: We should make sure this is a 32-bit constant
+      Imm.f = MO.getFPImm();
+      Value |= ((uint64_t)Imm.i) << 32;
+    }
+  }
+  return Value;
+}
+
+//===----------------------------------------------------------------------===//
+// Encoding helper functions
+//===----------------------------------------------------------------------===//
+
+unsigned SIMCCodeEmitter::getEncodingType(const MCInst &MI) const {
+  return MCII.get(MI.getOpcode()).TSFlags & SI_INSTR_FLAGS_ENCODING_MASK;
+}
+
+unsigned SIMCCodeEmitter::getEncodingBytes(const MCInst &MI) const {
+
+  // These instructions aren't real instructions with an encoding type, so
+  // we need to manually specify their size.
+  switch (MI.getOpcode()) {
+  default: break;
+  case AMDGPU::SI_LOAD_LITERAL_I32:
+  case AMDGPU::SI_LOAD_LITERAL_F32:
+    return 4;
+  }
+
+  unsigned encoding_type = getEncodingType(MI);
+  switch (encoding_type) {
+    case SIInstrEncodingType::EXP:
+    case SIInstrEncodingType::LDS:
+    case SIInstrEncodingType::MUBUF:
+    case SIInstrEncodingType::MTBUF:
+    case SIInstrEncodingType::MIMG:
+    case SIInstrEncodingType::VOP3:
+      return 8;
+    default:
+      return 4;
+  }
+}
+
+
+unsigned SIMCCodeEmitter::getRegBinaryCode(unsigned reg) const {
+  switch (reg) {
+    case AMDGPU::M0: return 124;
+    case AMDGPU::SREG_LIT_0: return 128;
+    case AMDGPU::SI_LITERAL_CONSTANT: return 255;
+    default: return MRI.getEncodingValue(reg);
+  }
+}
+