mozjs_sys 0.67.1

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 *
 * Copyright 2015 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef wasm_binary_h
#define wasm_binary_h

namespace js {
namespace wasm {

static const uint32_t MagicNumber = 0x6d736100;  // "\0asm"
static const uint32_t EncodingVersion = 0x01;

enum class SectionId {
  Custom = 0,
  Type = 1,
  Import = 2,
  Function = 3,
  Table = 4,
  Memory = 5,
  Global = 6,
  Export = 7,
  Start = 8,
  Elem = 9,
  Code = 10,
  Data = 11,
  DataCount = 12,
  GcFeatureOptIn = 42  // Arbitrary, but fits in 7 bits
};

enum class TypeCode {
  I32 = 0x7f,  // SLEB128(-0x01)
  I64 = 0x7e,  // SLEB128(-0x02)
  F32 = 0x7d,  // SLEB128(-0x03)
  F64 = 0x7c,  // SLEB128(-0x04)

  // A function pointer with any signature
  AnyFunc = 0x70,  // SLEB128(-0x10)

  // A reference to any type.
  AnyRef = 0x6f,

  // Type constructor for reference types.
  Ref = 0x6e,

  // Type constructor for function types
  Func = 0x60,  // SLEB128(-0x20)

  // Type constructor for structure types - unofficial
  Struct = 0x50,  // SLEB128(-0x30)

  // Special code representing the block signature ()->()
  BlockVoid = 0x40,  // SLEB128(-0x40)

  // Type designator for null - unofficial, will not appear in the binary format
  NullRef = 0x39,

  Limit = 0x80
};

enum class FuncTypeIdDescKind { None, Immediate, Global };

// A wasm::Trap represents a wasm-defined trap that can occur during execution
// which triggers a WebAssembly.RuntimeError. Generated code may jump to a Trap
// symbolically, passing the bytecode offset to report as the trap offset. The
// generated jump will be bound to a tiny stub which fills the offset and
// then jumps to a per-Trap shared stub at the end of the module.

enum class Trap {
  // The Unreachable opcode has been executed.
  Unreachable,
  // An integer arithmetic operation led to an overflow.
  IntegerOverflow,
  // Trying to coerce NaN to an integer.
  InvalidConversionToInteger,
  // Integer division by zero.
  IntegerDivideByZero,
  // Out of bounds on wasm memory accesses.
  OutOfBounds,
  // Unaligned on wasm atomic accesses; also used for non-standard ARM
  // unaligned access faults.
  UnalignedAccess,
  // call_indirect to null.
  IndirectCallToNull,
  // call_indirect signature mismatch.
  IndirectCallBadSig,
  // Dereference null pointer in operation on (Ref T)
  NullPointerDereference,

  // The internal stack space was exhausted. For compatibility, this throws
  // the same over-recursed error as JS.
  StackOverflow,

  // The wasm execution has potentially run too long and the engine must call
  // CheckForInterrupt(). This trap is resumable.
  CheckInterrupt,

  // Signal an error that was reported in C++ code.
  ThrowReported,

  Limit
};

// The representation of a null reference value throughout the compiler.

static const intptr_t NULLREF_VALUE = intptr_t((void*)nullptr);

enum class DefinitionKind {
  Function = 0x00,
  Table = 0x01,
  Memory = 0x02,
  Global = 0x03
};

enum class GlobalTypeImmediate { IsMutable = 0x1, AllowedMask = 0x1 };

enum class MemoryTableFlags {
  Default = 0x0,
  HasMaximum = 0x1,
  IsShared = 0x2,
};

enum class MemoryMasks { AllowUnshared = 0x1, AllowShared = 0x3 };

enum class InitializerKind {
  Active = 0x00,
  Passive = 0x01,
  ActiveWithIndex = 0x02
};

enum class Op {
  // Control flow operators
  Unreachable = 0x00,
  Nop = 0x01,
  Block = 0x02,
  Loop = 0x03,
  If = 0x04,
  Else = 0x05,
  End = 0x0b,
  Br = 0x0c,
  BrIf = 0x0d,
  BrTable = 0x0e,
  Return = 0x0f,

  // Call operators
  Call = 0x10,
  CallIndirect = 0x11,

  // Parametric operators
  Drop = 0x1a,
  Select = 0x1b,

  // Variable access
  GetLocal = 0x20,
  SetLocal = 0x21,
  TeeLocal = 0x22,
  GetGlobal = 0x23,
  SetGlobal = 0x24,
  TableGet = 0x25,  // Reftypes,
  TableSet = 0x26,  //   per proposal as of February 2019

  // Memory-related operators
  I32Load = 0x28,
  I64Load = 0x29,
  F32Load = 0x2a,
  F64Load = 0x2b,
  I32Load8S = 0x2c,
  I32Load8U = 0x2d,
  I32Load16S = 0x2e,
  I32Load16U = 0x2f,
  I64Load8S = 0x30,
  I64Load8U = 0x31,
  I64Load16S = 0x32,
  I64Load16U = 0x33,
  I64Load32S = 0x34,
  I64Load32U = 0x35,
  I32Store = 0x36,
  I64Store = 0x37,
  F32Store = 0x38,
  F64Store = 0x39,
  I32Store8 = 0x3a,
  I32Store16 = 0x3b,
  I64Store8 = 0x3c,
  I64Store16 = 0x3d,
  I64Store32 = 0x3e,
  MemorySize = 0x3f,
  MemoryGrow = 0x40,

  // Constants
  I32Const = 0x41,
  I64Const = 0x42,
  F32Const = 0x43,
  F64Const = 0x44,

  // Comparison operators
  I32Eqz = 0x45,
  I32Eq = 0x46,
  I32Ne = 0x47,
  I32LtS = 0x48,
  I32LtU = 0x49,
  I32GtS = 0x4a,
  I32GtU = 0x4b,
  I32LeS = 0x4c,
  I32LeU = 0x4d,
  I32GeS = 0x4e,
  I32GeU = 0x4f,
  I64Eqz = 0x50,
  I64Eq = 0x51,
  I64Ne = 0x52,
  I64LtS = 0x53,
  I64LtU = 0x54,
  I64GtS = 0x55,
  I64GtU = 0x56,
  I64LeS = 0x57,
  I64LeU = 0x58,
  I64GeS = 0x59,
  I64GeU = 0x5a,
  F32Eq = 0x5b,
  F32Ne = 0x5c,
  F32Lt = 0x5d,
  F32Gt = 0x5e,
  F32Le = 0x5f,
  F32Ge = 0x60,
  F64Eq = 0x61,
  F64Ne = 0x62,
  F64Lt = 0x63,
  F64Gt = 0x64,
  F64Le = 0x65,
  F64Ge = 0x66,

  // Numeric operators
  I32Clz = 0x67,
  I32Ctz = 0x68,
  I32Popcnt = 0x69,
  I32Add = 0x6a,
  I32Sub = 0x6b,
  I32Mul = 0x6c,
  I32DivS = 0x6d,
  I32DivU = 0x6e,
  I32RemS = 0x6f,
  I32RemU = 0x70,
  I32And = 0x71,
  I32Or = 0x72,
  I32Xor = 0x73,
  I32Shl = 0x74,
  I32ShrS = 0x75,
  I32ShrU = 0x76,
  I32Rotl = 0x77,
  I32Rotr = 0x78,
  I64Clz = 0x79,
  I64Ctz = 0x7a,
  I64Popcnt = 0x7b,
  I64Add = 0x7c,
  I64Sub = 0x7d,
  I64Mul = 0x7e,
  I64DivS = 0x7f,
  I64DivU = 0x80,
  I64RemS = 0x81,
  I64RemU = 0x82,
  I64And = 0x83,
  I64Or = 0x84,
  I64Xor = 0x85,
  I64Shl = 0x86,
  I64ShrS = 0x87,
  I64ShrU = 0x88,
  I64Rotl = 0x89,
  I64Rotr = 0x8a,
  F32Abs = 0x8b,
  F32Neg = 0x8c,
  F32Ceil = 0x8d,
  F32Floor = 0x8e,
  F32Trunc = 0x8f,
  F32Nearest = 0x90,
  F32Sqrt = 0x91,
  F32Add = 0x92,
  F32Sub = 0x93,
  F32Mul = 0x94,
  F32Div = 0x95,
  F32Min = 0x96,
  F32Max = 0x97,
  F32CopySign = 0x98,
  F64Abs = 0x99,
  F64Neg = 0x9a,
  F64Ceil = 0x9b,
  F64Floor = 0x9c,
  F64Trunc = 0x9d,
  F64Nearest = 0x9e,
  F64Sqrt = 0x9f,
  F64Add = 0xa0,
  F64Sub = 0xa1,
  F64Mul = 0xa2,
  F64Div = 0xa3,
  F64Min = 0xa4,
  F64Max = 0xa5,
  F64CopySign = 0xa6,

  // Conversions
  I32WrapI64 = 0xa7,
  I32TruncSF32 = 0xa8,
  I32TruncUF32 = 0xa9,
  I32TruncSF64 = 0xaa,
  I32TruncUF64 = 0xab,
  I64ExtendSI32 = 0xac,
  I64ExtendUI32 = 0xad,
  I64TruncSF32 = 0xae,
  I64TruncUF32 = 0xaf,
  I64TruncSF64 = 0xb0,
  I64TruncUF64 = 0xb1,
  F32ConvertSI32 = 0xb2,
  F32ConvertUI32 = 0xb3,
  F32ConvertSI64 = 0xb4,
  F32ConvertUI64 = 0xb5,
  F32DemoteF64 = 0xb6,
  F64ConvertSI32 = 0xb7,
  F64ConvertUI32 = 0xb8,
  F64ConvertSI64 = 0xb9,
  F64ConvertUI64 = 0xba,
  F64PromoteF32 = 0xbb,

  // Reinterpretations
  I32ReinterpretF32 = 0xbc,
  I64ReinterpretF64 = 0xbd,
  F32ReinterpretI32 = 0xbe,
  F64ReinterpretI64 = 0xbf,

  // Sign extension
  I32Extend8S = 0xc0,
  I32Extend16S = 0xc1,
  I64Extend8S = 0xc2,
  I64Extend16S = 0xc3,
  I64Extend32S = 0xc4,

  // GC ops
  RefNull = 0xd0,
  RefIsNull = 0xd1,
  RefFunc = 0xd2,

  RefEq = 0xf0,  // Unofficial + experimental

  FirstPrefix = 0xfc,
  MiscPrefix = 0xfc,
  ThreadPrefix = 0xfe,
  MozPrefix = 0xff,

  Limit = 0x100
};

inline bool IsPrefixByte(uint8_t b) { return b >= uint8_t(Op::FirstPrefix); }

// Opcodes in the "miscellaneous" opcode space.
enum class MiscOp {
  // Saturating float-to-int conversions
  I32TruncSSatF32 = 0x00,
  I32TruncUSatF32 = 0x01,
  I32TruncSSatF64 = 0x02,
  I32TruncUSatF64 = 0x03,
  I64TruncSSatF32 = 0x04,
  I64TruncUSatF32 = 0x05,
  I64TruncSSatF64 = 0x06,
  I64TruncUSatF64 = 0x07,

  // Bulk memory operations, per proposal as of February 2019.
  MemInit = 0x08,
  DataDrop = 0x09,
  MemCopy = 0x0a,
  MemFill = 0x0b,
  TableInit = 0x0c,
  ElemDrop = 0x0d,
  TableCopy = 0x0e,

  // Reftypes, per proposal as of February 2019.
  TableGrow = 0x0f,
  TableSize = 0x10,
  // TableFill = 0x11, // reserved

  // Structure operations.  Note, these are unofficial.
  StructNew = 0x50,
  StructGet = 0x51,
  StructSet = 0x52,
  StructNarrow = 0x53,

  Limit
};

// Opcodes from threads proposal as of June 30, 2017
enum class ThreadOp {
  // Wait and wake
  Wake = 0x00,
  I32Wait = 0x01,
  I64Wait = 0x02,

  // Load and store
  I32AtomicLoad = 0x10,
  I64AtomicLoad = 0x11,
  I32AtomicLoad8U = 0x12,
  I32AtomicLoad16U = 0x13,
  I64AtomicLoad8U = 0x14,
  I64AtomicLoad16U = 0x15,
  I64AtomicLoad32U = 0x16,
  I32AtomicStore = 0x17,
  I64AtomicStore = 0x18,
  I32AtomicStore8U = 0x19,
  I32AtomicStore16U = 0x1a,
  I64AtomicStore8U = 0x1b,
  I64AtomicStore16U = 0x1c,
  I64AtomicStore32U = 0x1d,

  // Read-modify-write operations
  I32AtomicAdd = 0x1e,
  I64AtomicAdd = 0x1f,
  I32AtomicAdd8U = 0x20,
  I32AtomicAdd16U = 0x21,
  I64AtomicAdd8U = 0x22,
  I64AtomicAdd16U = 0x23,
  I64AtomicAdd32U = 0x24,

  I32AtomicSub = 0x25,
  I64AtomicSub = 0x26,
  I32AtomicSub8U = 0x27,
  I32AtomicSub16U = 0x28,
  I64AtomicSub8U = 0x29,
  I64AtomicSub16U = 0x2a,
  I64AtomicSub32U = 0x2b,

  I32AtomicAnd = 0x2c,
  I64AtomicAnd = 0x2d,
  I32AtomicAnd8U = 0x2e,
  I32AtomicAnd16U = 0x2f,
  I64AtomicAnd8U = 0x30,
  I64AtomicAnd16U = 0x31,
  I64AtomicAnd32U = 0x32,

  I32AtomicOr = 0x33,
  I64AtomicOr = 0x34,
  I32AtomicOr8U = 0x35,
  I32AtomicOr16U = 0x36,
  I64AtomicOr8U = 0x37,
  I64AtomicOr16U = 0x38,
  I64AtomicOr32U = 0x39,

  I32AtomicXor = 0x3a,
  I64AtomicXor = 0x3b,
  I32AtomicXor8U = 0x3c,
  I32AtomicXor16U = 0x3d,
  I64AtomicXor8U = 0x3e,
  I64AtomicXor16U = 0x3f,
  I64AtomicXor32U = 0x40,

  I32AtomicXchg = 0x41,
  I64AtomicXchg = 0x42,
  I32AtomicXchg8U = 0x43,
  I32AtomicXchg16U = 0x44,
  I64AtomicXchg8U = 0x45,
  I64AtomicXchg16U = 0x46,
  I64AtomicXchg32U = 0x47,

  // CompareExchange
  I32AtomicCmpXchg = 0x48,
  I64AtomicCmpXchg = 0x49,
  I32AtomicCmpXchg8U = 0x4a,
  I32AtomicCmpXchg16U = 0x4b,
  I64AtomicCmpXchg8U = 0x4c,
  I64AtomicCmpXchg16U = 0x4d,
  I64AtomicCmpXchg32U = 0x4e,

  Limit
};

enum class MozOp {
  // ------------------------------------------------------------------------
  // These operators are emitted internally when compiling asm.js and are
  // rejected by wasm validation.  They are prefixed by MozPrefix.

  // asm.js-specific operators.  They start at 1 so as to check for
  // uninitialized (zeroed) storage.
  TeeGlobal = 0x01,
  I32Min,
  I32Max,
  I32Neg,
  I32BitNot,
  I32Abs,
  F32TeeStoreF64,
  F64TeeStoreF32,
  I32TeeStore8,
  I32TeeStore16,
  I64TeeStore8,
  I64TeeStore16,
  I64TeeStore32,
  I32TeeStore,
  I64TeeStore,
  F32TeeStore,
  F64TeeStore,
  F64Mod,
  F64Sin,
  F64Cos,
  F64Tan,
  F64Asin,
  F64Acos,
  F64Atan,
  F64Exp,
  F64Log,
  F64Pow,
  F64Atan2,

  // asm.js-style call_indirect with the callee evaluated first.
  OldCallDirect,
  OldCallIndirect,

  Limit
};

struct OpBytes {
  // b0 is a byte value but has a 16-bit representation to allow for a full
  // 256-value range plus a sentinel Limit value.
  uint16_t b0;
  // b1 is a LEB128 value but 32 bits is enough for now.
  uint32_t b1;

  explicit OpBytes(Op x) {
    b0 = uint16_t(x);
    b1 = 0;
  }
  OpBytes() = default;
};

static const char NameSectionName[] = "name";
static const char SourceMappingURLSectionName[] = "sourceMappingURL";

enum class NameType { Module = 0, Function = 1, Local = 2 };

enum class FieldFlags { Mutable = 0x01, AllowedMask = 0x01 };

// These limits are agreed upon with other engines for consistency.

static const unsigned MaxTypes = 1000000;
static const unsigned MaxFuncs = 1000000;
static const unsigned MaxTables =
    100000;  // TODO: get this into the shared limits spec
static const unsigned MaxImports = 100000;
static const unsigned MaxExports = 100000;
static const unsigned MaxGlobals = 1000000;
static const unsigned MaxDataSegments = 100000;
static const unsigned MaxElemSegments = 10000000;
static const unsigned MaxTableLength = 10000000;
static const unsigned MaxLocals = 50000;
static const unsigned MaxParams = 1000;
static const unsigned MaxStructFields = 1000;
static const unsigned MaxMemoryMaximumPages = 65536;
static const unsigned MaxStringBytes = 100000;
static const unsigned MaxModuleBytes = 1024 * 1024 * 1024;
static const unsigned MaxFunctionBytes = 7654321;

// These limits pertain to our WebAssembly implementation only.

static const unsigned MaxTableInitialLength = 10000000;
static const unsigned MaxBrTableElems = 1000000;
static const unsigned MaxMemoryInitialPages = 16384;
static const unsigned MaxCodeSectionBytes = MaxModuleBytes;

// A magic value of the FramePointer to indicate after a return to the entry
// stub that an exception has been caught and that we should throw.

static const unsigned FailFP = 0xbad;

// Asserted by Decoder::readVarU32.

static const unsigned MaxVarU32DecodedBytes = 5;

}  // namespace wasm
}  // namespace js

#endif  // wasm_binary_h