| // Copyright 2017 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef V8_WASM_BASELINE_LIFTOFF_REGISTER_H_ |
| #define V8_WASM_BASELINE_LIFTOFF_REGISTER_H_ |
| |
| #include <iosfwd> |
| #include <memory> |
| |
| #include "src/base/bits.h" |
| #include "src/wasm/baseline/liftoff-assembler-defs.h" |
| #include "src/wasm/wasm-opcodes.h" |
| |
| namespace v8 { |
| namespace internal { |
| namespace wasm { |
| |
| static constexpr bool kNeedI64RegPair = kSystemPointerSize == 4; |
| |
| enum RegClass : uint8_t { |
| kGpReg, |
| kFpReg, |
| // {kGpRegPair} equals {kNoReg} if {kNeedI64RegPair} is false. |
| kGpRegPair, |
| kNoReg = kGpRegPair + kNeedI64RegPair |
| }; |
| |
| enum RegPairHalf : uint8_t { kLowWord = 0, kHighWord = 1 }; |
| |
| static inline constexpr bool needs_reg_pair(ValueType type) { |
| return kNeedI64RegPair && type == kWasmI64; |
| } |
| |
| // TODO(clemensh): Use a switch once we require C++14 support. |
| static inline constexpr RegClass reg_class_for(ValueType type) { |
| return needs_reg_pair(type) // i64 on 32 bit |
| ? kGpRegPair |
| : type == kWasmI32 || type == kWasmI64 // int types |
| ? kGpReg |
| : type == kWasmF32 || type == kWasmF64 // float types |
| ? kFpReg |
| : kNoReg; // other (unsupported) types |
| } |
| |
| // Maximum code of a gp cache register. |
| static constexpr int kMaxGpRegCode = |
| 8 * sizeof(kLiftoffAssemblerGpCacheRegs) - |
| base::bits::CountLeadingZeros(kLiftoffAssemblerGpCacheRegs) - 1; |
| // Maximum code of an fp cache register. |
| static constexpr int kMaxFpRegCode = |
| 8 * sizeof(kLiftoffAssemblerFpCacheRegs) - |
| base::bits::CountLeadingZeros(kLiftoffAssemblerFpCacheRegs) - 1; |
| // LiftoffRegister encodes both gp and fp in a unified index space. |
| // [0 .. kMaxGpRegCode] encodes gp registers, |
| // [kMaxGpRegCode+1 .. kMaxGpRegCode + kMaxFpRegCode] encodes fp registers. |
| // I64 values on 32 bit platforms are stored in two registers, both encoded in |
| // the same LiftoffRegister value. |
| static constexpr int kAfterMaxLiftoffGpRegCode = kMaxGpRegCode + 1; |
| static constexpr int kAfterMaxLiftoffFpRegCode = |
| kAfterMaxLiftoffGpRegCode + kMaxFpRegCode + 1; |
| static constexpr int kAfterMaxLiftoffRegCode = kAfterMaxLiftoffFpRegCode; |
| static constexpr int kBitsPerLiftoffRegCode = |
| 32 - base::bits::CountLeadingZeros<uint32_t>(kAfterMaxLiftoffRegCode - 1); |
| static constexpr int kBitsPerGpRegCode = |
| 32 - base::bits::CountLeadingZeros<uint32_t>(kMaxGpRegCode); |
| static constexpr int kBitsPerGpRegPair = 1 + 2 * kBitsPerGpRegCode; |
| |
| class LiftoffRegister { |
| static constexpr int needed_bits = |
| Max(kNeedI64RegPair ? kBitsPerGpRegPair : 0, kBitsPerLiftoffRegCode); |
| using storage_t = std::conditional< |
| needed_bits <= 8, uint8_t, |
| std::conditional<needed_bits <= 16, uint16_t, uint32_t>::type>::type; |
| |
| static_assert(8 * sizeof(storage_t) >= needed_bits, |
| "chosen type is big enough"); |
| // Check for smallest required data type being chosen. |
| // Special case for uint8_t as there are no smaller types. |
| static_assert((8 * sizeof(storage_t) < 2 * needed_bits) || |
| (sizeof(storage_t) == sizeof(uint8_t)), |
| "chosen type is small enough"); |
| |
| public: |
| explicit LiftoffRegister(Register reg) : LiftoffRegister(reg.code()) { |
| DCHECK_NE(0, kLiftoffAssemblerGpCacheRegs & reg.bit()); |
| DCHECK_EQ(reg, gp()); |
| } |
| explicit LiftoffRegister(DoubleRegister reg) |
| : LiftoffRegister(kAfterMaxLiftoffGpRegCode + reg.code()) { |
| DCHECK_NE(0, kLiftoffAssemblerFpCacheRegs & reg.bit()); |
| DCHECK_EQ(reg, fp()); |
| } |
| |
| static LiftoffRegister from_liftoff_code(uint32_t code) { |
| DCHECK_LE(0, code); |
| DCHECK_GT(kAfterMaxLiftoffRegCode, code); |
| DCHECK_EQ(code, static_cast<storage_t>(code)); |
| return LiftoffRegister(code); |
| } |
| |
| static LiftoffRegister from_code(RegClass rc, int code) { |
| switch (rc) { |
| case kGpReg: |
| return LiftoffRegister(Register::from_code(code)); |
| case kFpReg: |
| return LiftoffRegister(DoubleRegister::from_code(code)); |
| default: |
| UNREACHABLE(); |
| } |
| } |
| |
| static LiftoffRegister ForPair(Register low, Register high) { |
| DCHECK(kNeedI64RegPair); |
| DCHECK_NE(low, high); |
| storage_t combined_code = low.code() | high.code() << kBitsPerGpRegCode | |
| 1 << (2 * kBitsPerGpRegCode); |
| return LiftoffRegister(combined_code); |
| } |
| |
| constexpr bool is_pair() const { |
| return kNeedI64RegPair && (code_ & (1 << (2 * kBitsPerGpRegCode))) != 0; |
| } |
| constexpr bool is_gp() const { return code_ < kAfterMaxLiftoffGpRegCode; } |
| constexpr bool is_fp() const { |
| return code_ >= kAfterMaxLiftoffGpRegCode && |
| code_ < kAfterMaxLiftoffFpRegCode; |
| } |
| |
| LiftoffRegister low() const { return LiftoffRegister(low_gp()); } |
| |
| LiftoffRegister high() const { return LiftoffRegister(high_gp()); } |
| |
| Register low_gp() const { |
| DCHECK(is_pair()); |
| static constexpr storage_t kCodeMask = (1 << kBitsPerGpRegCode) - 1; |
| return Register::from_code(code_ & kCodeMask); |
| } |
| |
| Register high_gp() const { |
| DCHECK(is_pair()); |
| static constexpr storage_t kCodeMask = (1 << kBitsPerGpRegCode) - 1; |
| return Register::from_code((code_ >> kBitsPerGpRegCode) & kCodeMask); |
| } |
| |
| Register gp() const { |
| DCHECK(is_gp()); |
| return Register::from_code(code_); |
| } |
| |
| DoubleRegister fp() const { |
| DCHECK(is_fp()); |
| return DoubleRegister::from_code(code_ - kAfterMaxLiftoffGpRegCode); |
| } |
| |
| int liftoff_code() const { |
| DCHECK(is_gp() || is_fp()); |
| return code_; |
| } |
| |
| RegClass reg_class() const { |
| return is_pair() ? kGpRegPair : is_gp() ? kGpReg : kFpReg; |
| } |
| |
| bool operator==(const LiftoffRegister other) const { |
| DCHECK_EQ(is_pair(), other.is_pair()); |
| return code_ == other.code_; |
| } |
| bool operator!=(const LiftoffRegister other) const { |
| DCHECK_EQ(is_pair(), other.is_pair()); |
| return code_ != other.code_; |
| } |
| bool overlaps(const LiftoffRegister other) const { |
| if (is_pair()) return low().overlaps(other) || high().overlaps(other); |
| if (other.is_pair()) return *this == other.low() || *this == other.high(); |
| return *this == other; |
| } |
| |
| private: |
| storage_t code_; |
| |
| explicit constexpr LiftoffRegister(storage_t code) : code_(code) {} |
| }; |
| ASSERT_TRIVIALLY_COPYABLE(LiftoffRegister); |
| |
| inline std::ostream& operator<<(std::ostream& os, LiftoffRegister reg) { |
| if (reg.is_pair()) { |
| return os << "<" << reg.low_gp() << "+" << reg.high_gp() << ">"; |
| } else if (reg.is_gp()) { |
| return os << reg.gp(); |
| } else { |
| return os << reg.fp(); |
| } |
| } |
| |
| class LiftoffRegList { |
| public: |
| class Iterator; |
| |
| static constexpr bool use_u16 = kAfterMaxLiftoffRegCode <= 16; |
| static constexpr bool use_u32 = !use_u16 && kAfterMaxLiftoffRegCode <= 32; |
| using storage_t = std::conditional< |
| use_u16, uint16_t, |
| std::conditional<use_u32, uint32_t, uint64_t>::type>::type; |
| |
| static constexpr storage_t kGpMask = storage_t{kLiftoffAssemblerGpCacheRegs}; |
| static constexpr storage_t kFpMask = storage_t{kLiftoffAssemblerFpCacheRegs} |
| << kAfterMaxLiftoffGpRegCode; |
| |
| constexpr LiftoffRegList() = default; |
| |
| Register set(Register reg) { return set(LiftoffRegister(reg)).gp(); } |
| DoubleRegister set(DoubleRegister reg) { |
| return set(LiftoffRegister(reg)).fp(); |
| } |
| |
| LiftoffRegister set(LiftoffRegister reg) { |
| if (reg.is_pair()) { |
| regs_ |= storage_t{1} << reg.low().liftoff_code(); |
| regs_ |= storage_t{1} << reg.high().liftoff_code(); |
| } else { |
| regs_ |= storage_t{1} << reg.liftoff_code(); |
| } |
| return reg; |
| } |
| |
| LiftoffRegister clear(LiftoffRegister reg) { |
| if (reg.is_pair()) { |
| regs_ &= ~(storage_t{1} << reg.low().liftoff_code()); |
| regs_ &= ~(storage_t{1} << reg.high().liftoff_code()); |
| } else { |
| regs_ &= ~(storage_t{1} << reg.liftoff_code()); |
| } |
| return reg; |
| } |
| |
| bool has(LiftoffRegister reg) const { |
| if (reg.is_pair()) { |
| DCHECK_EQ(has(reg.low()), has(reg.high())); |
| reg = reg.low(); |
| } |
| return (regs_ & (storage_t{1} << reg.liftoff_code())) != 0; |
| } |
| bool has(Register reg) const { return has(LiftoffRegister(reg)); } |
| bool has(DoubleRegister reg) const { return has(LiftoffRegister(reg)); } |
| |
| constexpr bool is_empty() const { return regs_ == 0; } |
| |
| constexpr unsigned GetNumRegsSet() const { |
| return base::bits::CountPopulation(regs_); |
| } |
| |
| constexpr LiftoffRegList operator&(const LiftoffRegList other) const { |
| return LiftoffRegList(regs_ & other.regs_); |
| } |
| |
| constexpr LiftoffRegList operator|(const LiftoffRegList other) const { |
| return LiftoffRegList(regs_ | other.regs_); |
| } |
| |
| constexpr bool operator==(const LiftoffRegList other) const { |
| return regs_ == other.regs_; |
| } |
| constexpr bool operator!=(const LiftoffRegList other) const { |
| return regs_ != other.regs_; |
| } |
| |
| LiftoffRegister GetFirstRegSet() const { |
| DCHECK(!is_empty()); |
| int first_code = base::bits::CountTrailingZeros(regs_); |
| return LiftoffRegister::from_liftoff_code(first_code); |
| } |
| |
| LiftoffRegister GetLastRegSet() const { |
| DCHECK(!is_empty()); |
| int last_code = |
| 8 * sizeof(regs_) - 1 - base::bits::CountLeadingZeros(regs_); |
| return LiftoffRegister::from_liftoff_code(last_code); |
| } |
| |
| LiftoffRegList MaskOut(const LiftoffRegList mask) const { |
| // Masking out is guaranteed to return a correct reg list, hence no checks |
| // needed. |
| return FromBits(regs_ & ~mask.regs_); |
| } |
| |
| RegList GetGpList() { return regs_ & kGpMask; } |
| RegList GetFpList() { return (regs_ & kFpMask) >> kAfterMaxLiftoffGpRegCode; } |
| |
| inline Iterator begin() const; |
| inline Iterator end() const; |
| |
| static LiftoffRegList FromBits(storage_t bits) { |
| DCHECK_EQ(bits, bits & (kGpMask | kFpMask)); |
| return LiftoffRegList(bits); |
| } |
| |
| template <storage_t bits> |
| static constexpr LiftoffRegList FromBits() { |
| static_assert(bits == (bits & (kGpMask | kFpMask)), "illegal reg list"); |
| return LiftoffRegList(bits); |
| } |
| |
| template <typename... Regs> |
| static LiftoffRegList ForRegs(Regs... regs) { |
| LiftoffRegList list; |
| for (LiftoffRegister reg : {LiftoffRegister(regs)...}) list.set(reg); |
| return list; |
| } |
| |
| private: |
| storage_t regs_ = 0; |
| |
| // Unchecked constructor. Only use for valid bits. |
| explicit constexpr LiftoffRegList(storage_t bits) : regs_(bits) {} |
| }; |
| ASSERT_TRIVIALLY_COPYABLE(LiftoffRegList); |
| |
| static constexpr LiftoffRegList kGpCacheRegList = |
| LiftoffRegList::FromBits<LiftoffRegList::kGpMask>(); |
| static constexpr LiftoffRegList kFpCacheRegList = |
| LiftoffRegList::FromBits<LiftoffRegList::kFpMask>(); |
| |
| class LiftoffRegList::Iterator { |
| public: |
| LiftoffRegister operator*() { return remaining_.GetFirstRegSet(); } |
| Iterator& operator++() { |
| remaining_.clear(remaining_.GetFirstRegSet()); |
| return *this; |
| } |
| bool operator==(Iterator other) { return remaining_ == other.remaining_; } |
| bool operator!=(Iterator other) { return remaining_ != other.remaining_; } |
| |
| private: |
| explicit Iterator(LiftoffRegList remaining) : remaining_(remaining) {} |
| friend class LiftoffRegList; |
| |
| LiftoffRegList remaining_; |
| }; |
| |
| LiftoffRegList::Iterator LiftoffRegList::begin() const { |
| return Iterator{*this}; |
| } |
| LiftoffRegList::Iterator LiftoffRegList::end() const { |
| return Iterator{LiftoffRegList{}}; |
| } |
| |
| static constexpr LiftoffRegList GetCacheRegList(RegClass rc) { |
| return rc == kFpReg ? kFpCacheRegList : kGpCacheRegList; |
| } |
| |
| inline std::ostream& operator<<(std::ostream& os, LiftoffRegList reglist) { |
| os << "{"; |
| for (bool first = true; !reglist.is_empty(); first = false) { |
| LiftoffRegister reg = reglist.GetFirstRegSet(); |
| reglist.clear(reg); |
| os << (first ? "" : ", ") << reg; |
| } |
| return os << "}"; |
| } |
| |
| } // namespace wasm |
| } // namespace internal |
| } // namespace v8 |
| |
| #endif // V8_WASM_BASELINE_LIFTOFF_REGISTER_H_ |