Target/AMDGPU/SIMachineFunctionInfo.h

//===- SIMachineFunctionInfo.h - SIMachineFunctionInfo interface -*- C++ -*-==//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIB_TARGET_AMDGPU_SIMACHINEFUNCTIONINFO_H
#define LLVM_LIB_TARGET_AMDGPU_SIMACHINEFUNCTIONINFO_H

#include "AMDGPUMachineFunction.h"
#include "MCTargetDesc/AMDGPUMCTargetDesc.h"
#include "SIRegisterInfo.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/Support/ErrorHandling.h"
#include <array>
#include <cassert>
#include <map>
#include <utility>

namespace llvm {

class AMDGPUImagePseudoSourceValue : public PseudoSourceValue {
public:
  explicit AMDGPUImagePseudoSourceValue() :
    PseudoSourceValue(PseudoSourceValue::TargetCustom) { }

  bool isConstant(const MachineFrameInfo *) const override {
    // This should probably be true for most images, but we will start by being
    // conservative.
    return false;
  }

  bool isAliased(const MachineFrameInfo *) const override {
    // FIXME: If we ever change image intrinsics to accept fat pointers, then
    // this could be true for some cases.
    return false;
  }

  bool mayAlias(const MachineFrameInfo*) const override {
    // FIXME: If we ever change image intrinsics to accept fat pointers, then
    // this could be true for some cases.
    return false;
  }
};

class AMDGPUBufferPseudoSourceValue : public PseudoSourceValue {
public:
  explicit AMDGPUBufferPseudoSourceValue() :
    PseudoSourceValue(PseudoSourceValue::TargetCustom) { }

  bool isConstant(const MachineFrameInfo *) const override {
    // This should probably be true for most images, but we will start by being
    // conservative.
    return false;
  }

  bool isAliased(const MachineFrameInfo *) const override {
    // FIXME: If we ever change image intrinsics to accept fat pointers, then
    // this could be true for some cases.
    return false;
  }

  bool mayAlias(const MachineFrameInfo*) const override {
    // FIXME: If we ever change image intrinsics to accept fat pointers, then
    // this could be true for some cases.
    return false;
  }
};

/// This class keeps track of the SPI_SP_INPUT_ADDR config register, which
/// tells the hardware which interpolation parameters to load.
class SIMachineFunctionInfo final : public AMDGPUMachineFunction {
  // FIXME: This should be removed and getPreloadedValue moved here.
  friend class SIRegisterInfo;

  unsigned TIDReg;

  // Registers that may be reserved for spilling purposes. These may be the same
  // as the input registers.
  unsigned ScratchRSrcReg;
  unsigned ScratchWaveOffsetReg;

  // This is the current function's incremented size from the kernel's scratch
  // wave offset register. For an entry function, this is exactly the same as
  // the ScratchWaveOffsetReg.
  unsigned FrameOffsetReg;

  // Top of the stack SGPR offset derived from the ScratchWaveOffsetReg.
  unsigned StackPtrOffsetReg;

  // Input registers for non-HSA ABI
  unsigned ImplicitBufferPtrUserSGPR;

  // Input registers setup for the HSA ABI.
  // User SGPRs in allocation order.
  unsigned PrivateSegmentBufferUserSGPR;
  unsigned DispatchPtrUserSGPR;
  unsigned QueuePtrUserSGPR;
  unsigned KernargSegmentPtrUserSGPR;
  unsigned DispatchIDUserSGPR;
  unsigned FlatScratchInitUserSGPR;
  unsigned PrivateSegmentSizeUserSGPR;
  unsigned GridWorkGroupCountXUserSGPR;
  unsigned GridWorkGroupCountYUserSGPR;
  unsigned GridWorkGroupCountZUserSGPR;

  // System SGPRs in allocation order.
  unsigned WorkGroupIDXSystemSGPR;
  unsigned WorkGroupIDYSystemSGPR;
  unsigned WorkGroupIDZSystemSGPR;
  unsigned WorkGroupInfoSystemSGPR;
  unsigned PrivateSegmentWaveByteOffsetSystemSGPR;

  // VGPR inputs. These are always v0, v1 and v2 for entry functions.
  unsigned WorkItemIDXVGPR;
  unsigned WorkItemIDYVGPR;
  unsigned WorkItemIDZVGPR;

  // Graphics info.
  unsigned PSInputAddr;
  unsigned PSInputEnable;

  bool ReturnsVoid;

  // A pair of default/requested minimum/maximum flat work group sizes.
  // Minimum - first, maximum - second.
  std::pair<unsigned, unsigned> FlatWorkGroupSizes;

  // A pair of default/requested minimum/maximum number of waves per execution
  // unit. Minimum - first, maximum - second.
  std::pair<unsigned, unsigned> WavesPerEU;

  // Stack object indices for work group IDs.
  std::array<int, 3> DebuggerWorkGroupIDStackObjectIndices;
  // Stack object indices for work item IDs.
  std::array<int, 3> DebuggerWorkItemIDStackObjectIndices;

  AMDGPUBufferPseudoSourceValue BufferPSV;
  AMDGPUImagePseudoSourceValue ImagePSV;

private:
  unsigned LDSWaveSpillSize;
  unsigned ScratchOffsetReg;
  unsigned NumUserSGPRs;
  unsigned NumSystemSGPRs;

  bool HasSpilledSGPRs;
  bool HasSpilledVGPRs;
  bool HasNonSpillStackObjects;

  unsigned NumSpilledSGPRs;
  unsigned NumSpilledVGPRs;

  // Feature bits required for inputs passed in user SGPRs.
  bool PrivateSegmentBuffer : 1;
  bool DispatchPtr : 1;
  bool QueuePtr : 1;
  bool KernargSegmentPtr : 1;
  bool DispatchID : 1;
  bool FlatScratchInit : 1;
  bool GridWorkgroupCountX : 1;
  bool GridWorkgroupCountY : 1;
  bool GridWorkgroupCountZ : 1;

  // Feature bits required for inputs passed in system SGPRs.
  bool WorkGroupIDX : 1; // Always initialized.
  bool WorkGroupIDY : 1;
  bool WorkGroupIDZ : 1;
  bool WorkGroupInfo : 1;
  bool PrivateSegmentWaveByteOffset : 1;

  bool WorkItemIDX : 1; // Always initialized.
  bool WorkItemIDY : 1;
  bool WorkItemIDZ : 1;

  // Private memory buffer
  // Compute directly in sgpr[0:1]
  // Other shaders indirect 64-bits at sgpr[0:1]
  bool ImplicitBufferPtr : 1;

  // Pointer to where the ABI inserts special kernel arguments separate from the
  // user arguments. This is an offset from the KernargSegmentPtr.
  bool ImplicitArgPtr : 1;

  MCPhysReg getNextUserSGPR() const {
    assert(NumSystemSGPRs == 0 && "System SGPRs must be added after user SGPRs");
    return AMDGPU::SGPR0 + NumUserSGPRs;
  }

  MCPhysReg getNextSystemSGPR() const {
    return AMDGPU::SGPR0 + NumUserSGPRs + NumSystemSGPRs;
  }

public:
  struct SpilledReg {
    unsigned VGPR = AMDGPU::NoRegister;
    int Lane = -1;

    SpilledReg() = default;
    SpilledReg(unsigned R, int L) : VGPR (R), Lane (L) { }

    bool hasLane() { return Lane != -1;}
    bool hasReg() { return VGPR != AMDGPU::NoRegister;}
  };

  struct SGPRSpillVGPRCSR {
    // VGPR used for SGPR spills
    unsigned VGPR;

    // If the VGPR is a CSR, the stack slot used to save/restore it in the
    // prolog/epilog.
    Optional<int> FI;

    SGPRSpillVGPRCSR(unsigned V, Optional<int> F) :
      VGPR(V),
      FI(F) {}
  };

private:
  // SGPR->VGPR spilling support.
  typedef std::pair<unsigned, unsigned> SpillRegMask;

  // Track VGPR + wave index for each subregister of the SGPR spilled to
  // frameindex key.
  DenseMap<int, std::vector<SpilledReg>> SGPRToVGPRSpills;
  unsigned NumVGPRSpillLanes = 0;
  SmallVector<SGPRSpillVGPRCSR, 2> SpillVGPRs;

public:

  SIMachineFunctionInfo(const MachineFunction &MF);

  ArrayRef<SpilledReg> getSGPRToVGPRSpills(int FrameIndex) const {
    auto I = SGPRToVGPRSpills.find(FrameIndex);
    return (I == SGPRToVGPRSpills.end()) ?
      ArrayRef<SpilledReg>() : makeArrayRef(I->second);
  }

  ArrayRef<SGPRSpillVGPRCSR> getSGPRSpillVGPRs() const {
    return SpillVGPRs;
  }

  bool allocateSGPRSpillToVGPR(MachineFunction &MF, int FI);
  void removeSGPRToVGPRFrameIndices(MachineFrameInfo &MFI);

  bool hasCalculatedTID() const { return TIDReg != AMDGPU::NoRegister; };
  unsigned getTIDReg() const { return TIDReg; };
  void setTIDReg(unsigned Reg) { TIDReg = Reg; }

  // Add user SGPRs.
  unsigned addPrivateSegmentBuffer(const SIRegisterInfo &TRI);
  unsigned addDispatchPtr(const SIRegisterInfo &TRI);
  unsigned addQueuePtr(const SIRegisterInfo &TRI);
  unsigned addKernargSegmentPtr(const SIRegisterInfo &TRI);
  unsigned addDispatchID(const SIRegisterInfo &TRI);
  unsigned addFlatScratchInit(const SIRegisterInfo &TRI);
  unsigned addImplicitBufferPtr(const SIRegisterInfo &TRI);

  // Add system SGPRs.
  unsigned addWorkGroupIDX() {
    WorkGroupIDXSystemSGPR = getNextSystemSGPR();
    NumSystemSGPRs += 1;
    return WorkGroupIDXSystemSGPR;
  }

  unsigned addWorkGroupIDY() {
    WorkGroupIDYSystemSGPR = getNextSystemSGPR();
    NumSystemSGPRs += 1;
    return WorkGroupIDYSystemSGPR;
  }

  unsigned addWorkGroupIDZ() {
    WorkGroupIDZSystemSGPR = getNextSystemSGPR();
    NumSystemSGPRs += 1;
    return WorkGroupIDZSystemSGPR;
  }

  unsigned addWorkGroupInfo() {
    WorkGroupInfoSystemSGPR = getNextSystemSGPR();
    NumSystemSGPRs += 1;
    return WorkGroupInfoSystemSGPR;
  }

  unsigned addPrivateSegmentWaveByteOffset() {
    PrivateSegmentWaveByteOffsetSystemSGPR = getNextSystemSGPR();
    NumSystemSGPRs += 1;
    return PrivateSegmentWaveByteOffsetSystemSGPR;
  }

  void setPrivateSegmentWaveByteOffset(unsigned Reg) {
    PrivateSegmentWaveByteOffsetSystemSGPR = Reg;
  }

  bool hasPrivateSegmentBuffer() const {
    return PrivateSegmentBuffer;
  }

  bool hasDispatchPtr() const {
    return DispatchPtr;
  }

  bool hasQueuePtr() const {
    return QueuePtr;
  }

  bool hasKernargSegmentPtr() const {
    return KernargSegmentPtr;
  }

  bool hasDispatchID() const {
    return DispatchID;
  }

  bool hasFlatScratchInit() const {
    return FlatScratchInit;
  }

  bool hasGridWorkgroupCountX() const {
    return GridWorkgroupCountX;
  }

  bool hasGridWorkgroupCountY() const {
    return GridWorkgroupCountY;
  }

  bool hasGridWorkgroupCountZ() const {
    return GridWorkgroupCountZ;
  }

  bool hasWorkGroupIDX() const {
    return WorkGroupIDX;
  }

  bool hasWorkGroupIDY() const {
    return WorkGroupIDY;
  }

  bool hasWorkGroupIDZ() const {
    return WorkGroupIDZ;
  }

  bool hasWorkGroupInfo() const {
    return WorkGroupInfo;
  }

  bool hasPrivateSegmentWaveByteOffset() const {
    return PrivateSegmentWaveByteOffset;
  }

  bool hasWorkItemIDX() const {
    return WorkItemIDX;
  }

  bool hasWorkItemIDY() const {
    return WorkItemIDY;
  }

  bool hasWorkItemIDZ() const {
    return WorkItemIDZ;
  }

  bool hasImplicitArgPtr() const {
    return ImplicitArgPtr;
  }

  bool hasImplicitBufferPtr() const {
    return ImplicitBufferPtr;
  }

  unsigned getNumUserSGPRs() const {
    return NumUserSGPRs;
  }

  unsigned getNumPreloadedSGPRs() const {
    return NumUserSGPRs + NumSystemSGPRs;
  }

  unsigned getPrivateSegmentWaveByteOffsetSystemSGPR() const {
    return PrivateSegmentWaveByteOffsetSystemSGPR;
  }

  /// \brief Returns the physical register reserved for use as the resource
  /// descriptor for scratch accesses.
  unsigned getScratchRSrcReg() const {
    return ScratchRSrcReg;
  }

  void setScratchRSrcReg(unsigned Reg) {
    assert(Reg != AMDGPU::NoRegister && "Should never be unset");
    ScratchRSrcReg = Reg;
  }

  unsigned getScratchWaveOffsetReg() const {
    return ScratchWaveOffsetReg;
  }

  unsigned getFrameOffsetReg() const {
    return FrameOffsetReg;
  }

  void setStackPtrOffsetReg(unsigned Reg) {
    StackPtrOffsetReg = Reg;
  }

  // Note the unset value for this is AMDGPU::SP_REG rather than
  // NoRegister. This is mostly a workaround for MIR tests where state that
  // can't be directly computed from the function is not preserved in serialized
  // MIR.
  unsigned getStackPtrOffsetReg() const {
    return StackPtrOffsetReg;
  }

  void setScratchWaveOffsetReg(unsigned Reg) {
    assert(Reg != AMDGPU::NoRegister && "Should never be unset");
    ScratchWaveOffsetReg = Reg;
    if (isEntryFunction())
      FrameOffsetReg = ScratchWaveOffsetReg;
  }

  unsigned getQueuePtrUserSGPR() const {
    return QueuePtrUserSGPR;
  }

  unsigned getImplicitBufferPtrUserSGPR() const {
    return ImplicitBufferPtrUserSGPR;
  }

  bool hasSpilledSGPRs() const {
    return HasSpilledSGPRs;
  }

  void setHasSpilledSGPRs(bool Spill = true) {
    HasSpilledSGPRs = Spill;
  }

  bool hasSpilledVGPRs() const {
    return HasSpilledVGPRs;
  }

  void setHasSpilledVGPRs(bool Spill = true) {
    HasSpilledVGPRs = Spill;
  }

  bool hasNonSpillStackObjects() const {
    return HasNonSpillStackObjects;
  }

  void setHasNonSpillStackObjects(bool StackObject = true) {
    HasNonSpillStackObjects = StackObject;
  }

  unsigned getNumSpilledSGPRs() const {
    return NumSpilledSGPRs;
  }

  unsigned getNumSpilledVGPRs() const {
    return NumSpilledVGPRs;
  }

  void addToSpilledSGPRs(unsigned num) {
    NumSpilledSGPRs += num;
  }

  void addToSpilledVGPRs(unsigned num) {
    NumSpilledVGPRs += num;
  }

  unsigned getPSInputAddr() const {
    return PSInputAddr;
  }

  unsigned getPSInputEnable() const {
    return PSInputEnable;
  }

  bool isPSInputAllocated(unsigned Index) const {
    return PSInputAddr & (1 << Index);
  }

  void markPSInputAllocated(unsigned Index) {
    PSInputAddr |= 1 << Index;
  }

  void markPSInputEnabled(unsigned Index) {
    PSInputEnable |= 1 << Index;
  }

  bool returnsVoid() const {
    return ReturnsVoid;
  }

  void setIfReturnsVoid(bool Value) {
    ReturnsVoid = Value;
  }

  /// \returns A pair of default/requested minimum/maximum flat work group sizes
  /// for this function.
  std::pair<unsigned, unsigned> getFlatWorkGroupSizes() const {
    return FlatWorkGroupSizes;
  }

  /// \returns Default/requested minimum flat work group size for this function.
  unsigned getMinFlatWorkGroupSize() const {
    return FlatWorkGroupSizes.first;
  }

  /// \returns Default/requested maximum flat work group size for this function.
  unsigned getMaxFlatWorkGroupSize() const {
    return FlatWorkGroupSizes.second;
  }

  /// \returns A pair of default/requested minimum/maximum number of waves per
  /// execution unit.
  std::pair<unsigned, unsigned> getWavesPerEU() const {
    return WavesPerEU;
  }

  /// \returns Default/requested minimum number of waves per execution unit.
  unsigned getMinWavesPerEU() const {
    return WavesPerEU.first;
  }

  /// \returns Default/requested maximum number of waves per execution unit.
  unsigned getMaxWavesPerEU() const {
    return WavesPerEU.second;
  }

  /// \returns Stack object index for \p Dim's work group ID.
  int getDebuggerWorkGroupIDStackObjectIndex(unsigned Dim) const {
    assert(Dim < 3);
    return DebuggerWorkGroupIDStackObjectIndices[Dim];
  }

  /// \brief Sets stack object index for \p Dim's work group ID to \p ObjectIdx.
  void setDebuggerWorkGroupIDStackObjectIndex(unsigned Dim, int ObjectIdx) {
    assert(Dim < 3);
    DebuggerWorkGroupIDStackObjectIndices[Dim] = ObjectIdx;
  }

  /// \returns Stack object index for \p Dim's work item ID.
  int getDebuggerWorkItemIDStackObjectIndex(unsigned Dim) const {
    assert(Dim < 3);
    return DebuggerWorkItemIDStackObjectIndices[Dim];
  }

  /// \brief Sets stack object index for \p Dim's work item ID to \p ObjectIdx.
  void setDebuggerWorkItemIDStackObjectIndex(unsigned Dim, int ObjectIdx) {
    assert(Dim < 3);
    DebuggerWorkItemIDStackObjectIndices[Dim] = ObjectIdx;
  }

  /// \returns SGPR used for \p Dim's work group ID.
  unsigned getWorkGroupIDSGPR(unsigned Dim) const {
    switch (Dim) {
    case 0:
      assert(hasWorkGroupIDX());
      return WorkGroupIDXSystemSGPR;
    case 1:
      assert(hasWorkGroupIDY());
      return WorkGroupIDYSystemSGPR;
    case 2:
      assert(hasWorkGroupIDZ());
      return WorkGroupIDZSystemSGPR;
    }
    llvm_unreachable("unexpected dimension");
  }

  /// \returns VGPR used for \p Dim' work item ID.
  unsigned getWorkItemIDVGPR(unsigned Dim) const {
    switch (Dim) {
    case 0:
      assert(hasWorkItemIDX());
      return AMDGPU::VGPR0;
    case 1:
      assert(hasWorkItemIDY());
      return AMDGPU::VGPR1;
    case 2:
      assert(hasWorkItemIDZ());
      return AMDGPU::VGPR2;
    }
    llvm_unreachable("unexpected dimension");
  }

  unsigned getLDSWaveSpillSize() const {
    return LDSWaveSpillSize;
  }

  const AMDGPUBufferPseudoSourceValue *getBufferPSV() const {
    return &BufferPSV;
  }

  const AMDGPUImagePseudoSourceValue *getImagePSV() const {
    return &ImagePSV;
  }
};

} // end namespace llvm

#endif // LLVM_LIB_TARGET_AMDGPU_SIMACHINEFUNCTIONINFO_H