RISCVTargetParser.h

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//===-- RISCVTargetParser - Parser for target features ----------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements a target parser to recognise hardware features
// for RISC-V CPUs.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_TARGETPARSER_RISCVTARGETPARSER_H
#define LLVM_TARGETPARSER_RISCVTARGETPARSER_H
 
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
 
namespace llvm {
 
class Triple;
 
namespace RISCV {
 
struct CPUModel {
  uint32_t MVendorID;
  uint64_t MArchID;
  uint64_t MImpID;
 
  bool isValid() const { return MVendorID != 0 && MArchID != 0 && MImpID != 0; }
 
  bool operator==(const CPUModel &Other) const {
    return MVendorID == Other.MVendorID && MArchID == Other.MArchID &&
           MImpID == Other.MImpID;
  }
};
 
struct CPUInfo {
  StringLiteral Name;
  StringLiteral DefaultMarch;
  bool FastScalarUnalignedAccess;
  bool FastVectorUnalignedAccess;
  CPUModel Model;
  bool is64Bit() const { return DefaultMarch.starts_with("rv64"); }
};
 
/// Fatal errors encountered during parsing.
struct ParserError : public ErrorInfo<ParserError, StringError> {
  using ErrorInfo<ParserError, StringError>::ErrorInfo;
  explicit ParserError(const Twine &S)
      : ErrorInfo(S, inconvertibleErrorCode()) {}
  LLVM_ABI static char ID;
};
 
/// Warnings encountered during parsing.
struct ParserWarning : public ErrorInfo<ParserWarning, StringError> {
  using ErrorInfo<ParserWarning, StringError>::ErrorInfo;
  explicit ParserWarning(const Twine &S)
      : ErrorInfo(S, inconvertibleErrorCode()) {}
  LLVM_ABI static char ID;
};
 
// We use 64 bits as the known part in the scalable vector types.
static constexpr unsigned RVVBitsPerBlock = 64;
static constexpr unsigned RVVBytesPerBlock = RVVBitsPerBlock / 8;
 
LLVM_ABI void getFeaturesForCPU(StringRef CPU,
                                SmallVectorImpl<std::string> &EnabledFeatures,
                                bool NeedPlus = false);
LLVM_ABI void getAllTuneFeatures(SmallVectorImpl<StringRef> &TuneFeatures);
LLVM_ABI void
getCPUConfigurableTuneFeatures(StringRef CPU,
                               SmallVectorImpl<StringRef> &Directives);
/// Parse the tune feature string with the respective processor. If \p ProcName
/// is empty, directives are not filtered by processor.
LLVM_ABI Error
parseTuneFeatureString(StringRef ProcName, StringRef TFString,
                       SmallVectorImpl<std::string> &TuneFeatures);
LLVM_ABI bool parseCPU(StringRef CPU, bool IsRV64);
LLVM_ABI bool parseTuneCPU(StringRef CPU, bool IsRV64);
LLVM_ABI StringRef getMArchFromMcpu(StringRef CPU);
LLVM_ABI void fillValidCPUArchList(SmallVectorImpl<StringRef> &Values,
                                   bool IsRV64);
LLVM_ABI void fillValidTuneCPUArchList(SmallVectorImpl<StringRef> &Values,
                                       bool IsRV64);
LLVM_ABI bool hasFastScalarUnalignedAccess(StringRef CPU);
LLVM_ABI bool hasFastVectorUnalignedAccess(StringRef CPU);
LLVM_ABI bool hasValidCPUModel(StringRef CPU);
LLVM_ABI CPUModel getCPUModel(StringRef CPU);
LLVM_ABI StringRef getCPUNameFromCPUModel(const CPUModel &Model);
 
} // namespace RISCV
 
namespace RISCVCFI {
enum class ZicfilpLabelSchemeKind {
  Invalid,
  Unlabeled,
  FuncSig,
};
 
// See clang::getCFBranchLabelSchemeFlagVal() for possible CFBranchLabelScheme.
inline ZicfilpLabelSchemeKind
getZicfilpLabelScheme(const StringRef CFBranchLabelScheme) {
  return StringSwitch<ZicfilpLabelSchemeKind>(CFBranchLabelScheme)
      .Case("unlabeled", ZicfilpLabelSchemeKind::Unlabeled)
      .Case("func-sig", ZicfilpLabelSchemeKind::FuncSig)
      .Default(ZicfilpLabelSchemeKind::Invalid);
}
} // namespace RISCVCFI
 
namespace RISCVVType {
enum VLMUL : uint8_t {
  LMUL_1 = 0,
  LMUL_2,
  LMUL_4,
  LMUL_8,
  LMUL_RESERVED,
  LMUL_F8,
  LMUL_F4,
  LMUL_F2
};
 
enum {
  TAIL_UNDISTURBED_MASK_UNDISTURBED = 0,
  TAIL_AGNOSTIC = 1,
  MASK_AGNOSTIC = 2,
};
 
// Is this a SEW value that can be encoded into the VTYPE format.
inline static bool isValidSEW(unsigned SEW) {
  return isPowerOf2_32(SEW) && SEW >= 8 && SEW <= 64;
}
 
// Is this a LMUL value that can be encoded into the VTYPE format.
inline static bool isValidLMUL(unsigned LMUL, bool Fractional) {
  return isPowerOf2_32(LMUL) && LMUL <= 8 && (!Fractional || LMUL != 1);
}
 
LLVM_ABI unsigned encodeVTYPE(VLMUL VLMUL, unsigned SEW, bool TailAgnostic,
                              bool MaskAgnostic, bool AltFmt = false);
 
LLVM_ABI unsigned encodeXSfmmVType(unsigned SEW, unsigned Widen, bool AltFmt);
 
namespace IME {
inline static bool isValidLambda(unsigned Lambda) {
  return Lambda == 0 || (isPowerOf2_32(Lambda) && Lambda <= 64);
}
 
LLVM_ABI unsigned encodeLambda(unsigned Lambda);
 
LLVM_ABI std::optional<unsigned> decodeLambda(unsigned Encoding);
 
LLVM_ABI uint64_t getVTypeFieldsMask(unsigned XLen);
 
LLVM_ABI uint64_t encodeVTypeFields(unsigned XLen, unsigned Lambda,
                                    bool AltFmtA, bool AltFmtB,
                                    bool BlockSize16);
 
LLVM_ABI uint64_t addVTypeFields(uint64_t VType, unsigned XLen, unsigned Lambda,
                                 bool AltFmtA, bool AltFmtB, bool BlockSize16);
 
LLVM_ABI unsigned getLambdaEncoding(uint64_t VType, unsigned XLen);
 
LLVM_ABI std::optional<unsigned> getLambda(uint64_t VType, unsigned XLen);
 
LLVM_ABI bool isAltFmtA(uint64_t VType, unsigned XLen);
 
LLVM_ABI bool isAltFmtB(uint64_t VType, unsigned XLen);
 
LLVM_ABI bool isBlockSize16(uint64_t VType, unsigned XLen);
} // namespace IME
 
inline static VLMUL getVLMUL(unsigned VType) {
  unsigned VLMul = VType & 0x7;
  return static_cast<VLMUL>(VLMul);
}
 
// Decode VLMUL into 1,2,4,8 and fractional indicator.
LLVM_ABI std::pair<unsigned, bool> decodeVLMUL(VLMUL VLMul);
 
inline static VLMUL encodeLMUL(unsigned LMUL, bool Fractional) {
  assert(isValidLMUL(LMUL, Fractional) && "Unsupported LMUL");
  unsigned LmulLog2 = Log2_32(LMUL);
  return static_cast<VLMUL>(Fractional ? 8 - LmulLog2 : LmulLog2);
}
 
inline static unsigned decodeVSEW(unsigned VSEW) {
  assert(VSEW < 8 && "Unexpected VSEW value");
  return 1 << (VSEW + 3);
}
 
inline static unsigned encodeSEW(unsigned SEW) {
  assert(isValidSEW(SEW) && "Unexpected SEW value");
  return Log2_32(SEW) - 3;
}
 
inline static unsigned getSEW(unsigned VType) {
  unsigned VSEW = (VType >> 3) & 0x7;
  return decodeVSEW(VSEW);
}
 
inline static unsigned decodeTWiden(unsigned TWiden) {
  assert((TWiden == 1 || TWiden == 2 || TWiden == 3) &&
         "Unexpected TWiden value");
  return 1 << (TWiden - 1);
}
 
inline static bool hasXSfmmWiden(unsigned VType) {
  unsigned TWiden = (VType >> 9) & 0x3;
  return TWiden != 0;
}
 
inline static unsigned getXSfmmWiden(unsigned VType) {
  unsigned TWiden = (VType >> 9) & 0x3;
  assert(TWiden != 0 && "Invalid widen value");
  return 1 << (TWiden - 1);
}
 
inline static bool isTailAgnostic(unsigned VType) { return VType & 0x40; }
 
inline static bool isMaskAgnostic(unsigned VType) { return VType & 0x80; }
 
inline static bool isAltFmt(unsigned VType) { return VType & 0x100; }
 
inline static bool isValidVType(unsigned VType) {
  return getSEW(VType) <= 64 && getVLMUL(VType) != LMUL_RESERVED &&
         (!isAltFmt(VType) || getSEW(VType) < 32);
}
 
static inline bool isValidXSfmmVType(unsigned VTypeI) {
  return (VTypeI & ~0x738) == 0 && RISCVVType::hasXSfmmWiden(VTypeI) &&
         RISCVVType::getSEW(VTypeI) * RISCVVType::getXSfmmWiden(VTypeI) <= 64 &&
         isValidVType(VTypeI);
}
 
LLVM_ABI void printVType(unsigned VType, raw_ostream &OS);
 
LLVM_ABI void printXSfmmVType(unsigned VType, raw_ostream &OS);
 
LLVM_ABI unsigned getSEWLMULRatio(unsigned SEW, VLMUL VLMul);
 
LLVM_ABI std::optional<VLMUL> getSameRatioLMUL(unsigned Ratio, unsigned EEW);
} // namespace RISCVVType
 
} // namespace llvm
 
#endif