/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- * vim: set ts=8 sw=2 et tw=0 ft=c: * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #ifndef vm_Opcodes_h #define vm_Opcodes_h #include #include #include "js/TypeDecls.h" // clang-format off /* * [SMDOC] Bytecode Definitions * * SpiderMonkey bytecode instructions. * * To use this header, define a macro of the form: * * #define MACRO(op, op_snake, token, length, nuses, ndefs, format) ... * * Then `FOR_EACH_OPCODE(MACRO)` invokes `MACRO` for every opcode. * * Field Description * ----- ----------- * op UpperCamelCase form of opcode id * op_snake snake_case form of opcode id * token Pretty-printer string, or null if ugly * length Number of bytes including any immediate operands * nuses Number of stack slots consumed by bytecode, -1 if variadic * ndefs Number of stack slots produced by bytecode * format JOF_ flags describing instruction operand layout, etc. * * For more about `format`, see the comments on the `JOF_` constants defined in * BytecodeUtil.h. * * * [SMDOC] Bytecode Invariants * * Creating scripts that do not follow the rules can lead to undefined * behavior. Bytecode has many consumers, not just the interpreter: JITs, * analyses, the debugger. That's why the rules below apply even to code that * can't be reached in ordinary execution (such as code after an infinite loop * or inside an `if (false)` block). * * The `code()` of a script must be a packed (not aligned) sequence of valid * instructions from start to end. Each instruction has a single byte opcode * followed by a number of operand bytes based on the opcode. * * ## Jump instructions * * Operands named `offset`, `forwardOffset`, or `defaultOffset` are jump * offsets, the distance in bytes from the start of the current instruction to * the start of another instruction in the same script. Operands named * `forwardOffset` or `defaultOffset` must be positive. * * Forward jumps must jump to a `JSOp::JumpTarget` instruction. Backward jumps, * indicated by negative offsets, must jump to a `JSOp::LoopHead` instruction. * Jump offsets can't be zero. * * Needless to say, scripts must not contain overlapping instruction sequences * (in the sense of ). * * A script's `trynotes` and `scopeNotes` impose further constraints. Each try * note and each scope note marks a region of the bytecode where some invariant * holds, or some cleanup behavior is needed--that there's a for-in iterator in * a particular stack slot, for instance, which must be closed on error. All * paths into the span must establish that invariant. In practice, this means * other code never jumps into the span: the only way in is to execute the * bytecode instruction that sets up the invariant (in our example, * `JSOp::Iter`). * * If a script's `trynotes` (see "Try Notes" in JSScript.h) contain a * `JSTRY_CATCH` or `JSTRY_FINALLY` span, there must be a `JSOp::Try` * instruction immediately before the span and a `JSOp::JumpTarget immediately * after it. Instructions must not jump to this `JSOp::JumpTarget`. (The VM puts * us there on exception.) Furthermore, the instruction sequence immediately * following a `JSTRY_CATCH` span must read `JumpTarget; Exception` or, in * non-function scripts, `JumpTarget; Undefined; SetRval; Exception`. (These * instructions run with an exception pending; other instructions aren't * designed to handle that.) * * Unreachable instructions are allowed, but they have to follow all the rules. * * Control must not reach the end of a script. (Currently, the last instruction * is always JSOp::RetRval.) * * ## Other operands * * Operands named `nameIndex` or `atomIndex` (which appear on instructions that * have `JOF_ATOM` in the `format` field) must be valid indexes into * `script->atoms()`. * * Operands named `argc` (`JOF_ARGC`) are argument counts for call * instructions. `argc` must be small enough that the instruction's nuses is <= * the current stack depth (see "Stack depth" below). * * Operands named `argno` (`JOF_QARG`) refer to an argument of the current * function. `argno` must be in the range `0..script->function()->nargs()`. * Instructions with these operands must appear only in function scripts. * * Operands named `localno` (`JOF_LOCAL`) refer to a local variable stored in * the stack frame. `localno` must be in the range `0..script->nfixed()`. * * Operands named `resumeIndex` (`JOF_RESUMEINDEX`) refer to a resume point in * the current script. `resumeIndex` must be a valid index into * `script->resumeOffsets()`. * * Operands named `hops` and `slot` (`JOF_ENVCOORD`) refer a slot in an * `EnvironmentObject`. At run time, they must point to a fixed slot in an * object on the current environment chain. See `EnvironmentCoordinates`. * * Operands with the following names must be valid indexes into * `script->gcthings()`, and the pointer in the vector must point to the right * type of thing: * * - `objectIndex` (`JOF_OBJECT`): `PlainObject*` or `ArrayObject*` * - `baseobjIndex` (`JOF_OBJECT`): `PlainObject*` * - `funcIndex` (`JOF_OBJECT`): `JSFunction*` * - `regexpIndex` (`JOF_REGEXP`): `RegExpObject*` * - `shapeIndex` (`JOF_SHAPE`): `Shape*` * - `scopeIndex` (`JOF_SCOPE`): `Scope*` * - `lexicalScopeIndex` (`JOF_SCOPE`): `LexicalScope*` * - `classBodyScopeIndex` (`JOF_SCOPE`): `ClassBodyScope*` * - `withScopeIndex` (`JOF_SCOPE`): `WithScope*` * - `bigIntIndex` (`JOF_BIGINT`): `BigInt*` * * Operands named `icIndex` (`JOF_ICINDEX`) must be exactly the number of * preceding instructions in the script that have the JOF_IC flag. * (Rationale: Each JOF_IC instruction has a unique entry in * `script->jitScript()->icEntries()`. At run time, in the bytecode * interpreter, we have to find that entry. We could store the IC index as an * operand to each JOF_IC instruction, but it's more memory-efficient to use a * counter and reset the counter to `icIndex` after each jump.) * * ## Stack depth * * Each instruction has a compile-time stack depth, the number of values on the * interpreter stack just before executing the instruction. It isn't explicitly * present in the bytecode itself, but (for reachable instructions, anyway) * it's a function of the bytecode. * * - The first instruction has stack depth 0. * * - Each successor of an instruction X has a stack depth equal to * * X's stack depth - `js::StackUses(X)` + `js::StackDefs(X)` * * except for `JSOp::Case` (below). * * X's "successors" are: the next instruction in the script, if * `js::FlowsIntoNext(op)` is true for X's opcode; one or more * `JSOp::JumpTarget`s elsewhere, if X is a forward jump or * `JSOp::TableSwitch`; and/or a `JSOp::LoopHead` if it's a backward jump. * * - `JSOp::Case` is a special case because its stack behavior is eccentric. * The formula above is correct for the next instruction. The jump target * has a stack depth that is 1 less. * * - The `JSOp::JumpTarget` instruction immediately following a `JSTRY_CATCH` * or `JSTRY_FINALLY` span has the same stack depth as the `JSOp::Try` * instruction that precedes the span. * * Every instruction covered by the `JSTRY_CATCH` or `JSTRY_FINALLY` span * must have a stack depth >= that value, so that error recovery is * guaranteed to find enough values on the stack to resume there. * * - `script->nslots() - script->nfixed()` must be >= the maximum stack * depth of any instruction in `script`. (The stack frame must be big * enough to run the code.) * * `BytecodeParser::parse()` computes stack depths for every reachable * instruction in a script. * * ## Scopes and environments * * As with stack depth, each instruction has a static scope, which is a * compile-time characterization of the eventual run-time environment chain * when that instruction executes. Just as every instruction has a stack budget * (nuses/ndefs), every instruction either pushes a scope, pops a scope, or * neither. The same successor relation applies as above. * * Every scope used in a script is stored in the `JSScript::gcthings()` vector. * They can be accessed using `getScope(index)` if you know what `index` to * pass. * * The scope of every instruction (that's reachable via the successor relation) * is given in two independent ways: by the bytecode itself and by the scope * notes. The two sources must agree. * * ## Further rules * * All reachable instructions must be reachable without taking any backward * edges. * * Instructions with the `JOF_CHECKSLOPPY` flag must not be used in strict mode * code. `JOF_CHECKSTRICT` instructions must not be used in nonstrict code. * * Many instructions have their own additional rules. These are documented on * the various opcodes below (look for the word "must"). */ // clang-format on // clang-format off /* * SpiderMonkey bytecode categorization (as used in generated documentation): * * [Index] * [Constants] * [Compound primitives] * Record literals * Tuple literals * [Expressions] * Unary operators * Binary operators * Conversions * Other expressions * [Objects] * Creating objects * Defining properties * Accessing properties * Super * Enumeration * Iteration * SetPrototype * Array literals * RegExp literals * Built-in objects * [Functions] * Creating functions * Creating constructors * Calls * Generators and async functions * [Control flow] * Jump targets * Jumps * Return * Exceptions * [Variables and scopes] * Initialization * Looking up bindings * Getting binding values * Setting binding values * Entering and leaving environments * Creating and deleting bindings * Function environment setup * [Stack operations] * [Other] */ // clang-format on // clang-format off #define FOR_EACH_OPCODE(MACRO) \ /* * Push `undefined`. * * Category: Constants * Operands: * Stack: => undefined */ \ MACRO(Undefined, undefined, "", 1, 0, 1, JOF_BYTE) \ /* * Push `null`. * * Category: Constants * Operands: * Stack: => null */ \ MACRO(Null, null, "null", 1, 0, 1, JOF_BYTE) \ /* * Push a boolean constant. * * Category: Constants * Operands: * Stack: => true/false */ \ MACRO(False, false_, "false", 1, 0, 1, JOF_BYTE) \ MACRO(True, true_, "true", 1, 0, 1, JOF_BYTE) \ /* * Push the `int32_t` immediate operand as an `Int32Value`. * * `JSOp::Zero`, `JSOp::One`, `JSOp::Int8`, `JSOp::Uint16`, and `JSOp::Uint24` * are all compact encodings for `JSOp::Int32`. * * Category: Constants * Operands: int32_t val * Stack: => val */ \ MACRO(Int32, int32, NULL, 5, 0, 1, JOF_INT32) \ /* * Push the number `0`. * * Category: Constants * Operands: * Stack: => 0 */ \ MACRO(Zero, zero, "0", 1, 0, 1, JOF_BYTE) \ /* * Push the number `1`. * * Category: Constants * Operands: * Stack: => 1 */ \ MACRO(One, one, "1", 1, 0, 1, JOF_BYTE) \ /* * Push the `int8_t` immediate operand as an `Int32Value`. * * Category: Constants * Operands: int8_t val * Stack: => val */ \ MACRO(Int8, int8, NULL, 2, 0, 1, JOF_INT8) \ /* * Push the `uint16_t` immediate operand as an `Int32Value`. * * Category: Constants * Operands: uint16_t val * Stack: => val */ \ MACRO(Uint16, uint16, NULL, 3, 0, 1, JOF_UINT16) \ /* * Push the `uint24_t` immediate operand as an `Int32Value`. * * Category: Constants * Operands: uint24_t val * Stack: => val */ \ MACRO(Uint24, uint24, NULL, 4, 0, 1, JOF_UINT24) \ /* * Push the 64-bit floating-point immediate operand as a `DoubleValue`. * * If the operand is a NaN, it must be the canonical NaN (see * `JS::detail::CanonicalizeNaN`). * * Category: Constants * Operands: double val * Stack: => val */ \ MACRO(Double, double_, NULL, 9, 0, 1, JOF_DOUBLE) \ /* * Push the BigInt constant `script->getBigInt(bigIntIndex)`. * * Category: Constants * Operands: uint32_t bigIntIndex * Stack: => bigint */ \ MACRO(BigInt, big_int, NULL, 5, 0, 1, JOF_BIGINT) \ /* * Push the string constant `script->getAtom(atomIndex)`. * * Category: Constants * Operands: uint32_t atomIndex * Stack: => string */ \ MACRO(String, string, NULL, 5, 0, 1, JOF_STRING) \ /* * Push a well-known symbol. * * `symbol` must be in range for `JS::SymbolCode`. * * Category: Constants * Operands: uint8_t symbol (the JS::SymbolCode of the symbol to use) * Stack: => symbol */ \ MACRO(Symbol, symbol, NULL, 2, 0, 1, JOF_UINT8) \ /* * Pop the top value on the stack, discard it, and push `undefined`. * * Implements: [The `void` operator][1], step 3. * * [1]: https://tc39.es/ecma262/#sec-void-operator * * Category: Expressions * Type: Unary operators * Operands: * Stack: val => undefined */ \ MACRO(Void, void_, NULL, 1, 1, 1, JOF_BYTE) \ /* * [The `typeof` operator][1]. * * Infallible. The result is always a string that depends on the [type][2] * of `val`. * * `JSOp::Typeof` and `JSOp::TypeofExpr` are the same except * that--amazingly--`JSOp::Typeof` affects the behavior of an immediately * *preceding* `JSOp::GetName` or `JSOp::GetGName` instruction! This is how * we implement [`typeof`][1] step 2, making `typeof nonExistingVariable` * return `"undefined"` instead of throwing a ReferenceError. * * In a global scope: * * - `typeof x` compiles to `GetGName "x"; Typeof`. * - `typeof (0, x)` compiles to `GetGName "x"; TypeofExpr`. * * Emitting the same bytecode for these two expressions would be a bug. * Per spec, the latter throws a ReferenceError if `x` doesn't exist. * * [1]: https://tc39.es/ecma262/#sec-typeof-operator * [2]: https://tc39.es/ecma262/#sec-ecmascript-language-types * * Category: Expressions * Type: Unary operators * Operands: * Stack: val => (typeof val) */ \ MACRO(Typeof, typeof_, NULL, 1, 1, 1, JOF_BYTE|JOF_IC) \ MACRO(TypeofExpr, typeof_expr, NULL, 1, 1, 1, JOF_BYTE|JOF_IC) \ /* * [The unary `+` operator][1]. * * `+val` doesn't do any actual math. It just calls [ToNumber][2](val). * * The conversion can call `.toString()`/`.valueOf()` methods and can * throw. The result on success is always a Number. (Per spec, unary `-` * supports BigInts, but unary `+` does not.) * * [1]: https://tc39.es/ecma262/#sec-unary-plus-operator * [2]: https://tc39.es/ecma262/#sec-tonumber * * Category: Expressions * Type: Unary operators * Operands: * Stack: val => (+val) */ \ MACRO(Pos, pos, "+ ", 1, 1, 1, JOF_BYTE|JOF_IC) \ /* * [The unary `-` operator][1]. * * Convert `val` to a numeric value, then push `-val`. The conversion can * call `.toString()`/`.valueOf()` methods and can throw. The result on * success is always numeric. * * [1]: https://tc39.es/ecma262/#sec-unary-minus-operator * * Category: Expressions * Type: Unary operators * Operands: * Stack: val => (-val) */ \ MACRO(Neg, neg, "- ", 1, 1, 1, JOF_BYTE|JOF_IC) \ /* * [The bitwise NOT operator][1] (`~`). * * `val` is converted to an integer, then bitwise negated. The conversion * can call `.toString()`/`.valueOf()` methods and can throw. The result on * success is always an Int32 or BigInt value. * * [1]: https://tc39.es/ecma262/#sec-bitwise-not-operator * * Category: Expressions * Type: Unary operators * Operands: * Stack: val => (~val) */ \ MACRO(BitNot, bit_not, "~", 1, 1, 1, JOF_BYTE|JOF_IC) \ /* * [The logical NOT operator][1] (`!`). * * `val` is first converted with [ToBoolean][2], then logically * negated. The result is always a boolean value. This does not call * user-defined methods and can't throw. * * [1]: https://tc39.es/ecma262/#sec-logical-not-operator * [2]: https://tc39.es/ecma262/#sec-toboolean * * Category: Expressions * Type: Unary operators * Operands: * Stack: val => (!val) */ \ MACRO(Not, not_, "!", 1, 1, 1, JOF_BYTE|JOF_IC) \ /* * [Binary bitwise operations][1] (`|`, `^`, `&`). * * The arguments are converted to integers first. The conversion can call * `.toString()`/`.valueOf()` methods and can throw. The result on success * is always an Int32 or BigInt Value. * * [1]: https://tc39.es/ecma262/#sec-binary-bitwise-operators * * Category: Expressions * Type: Binary operators * Operands: * Stack: lval, rval => (lval OP rval) */ \ MACRO(BitOr, bit_or, "|", 1, 2, 1, JOF_BYTE|JOF_IC) \ MACRO(BitXor, bit_xor, "^", 1, 2, 1, JOF_BYTE|JOF_IC) \ MACRO(BitAnd, bit_and, "&", 1, 2, 1, JOF_BYTE|JOF_IC) \ /* * Loose equality operators (`==` and `!=`). * * Pop two values, compare them, and push the boolean result. The * comparison may perform conversions that call `.toString()`/`.valueOf()` * methods and can throw. * * Implements: [Abstract Equality Comparison][1]. * * [1]: https://tc39.es/ecma262/#sec-abstract-equality-comparison * * Category: Expressions * Type: Binary operators * Operands: * Stack: lval, rval => (lval OP rval) */ \ MACRO(Eq, eq, "==", 1, 2, 1, JOF_BYTE|JOF_IC) \ MACRO(Ne, ne, "!=", 1, 2, 1, JOF_BYTE|JOF_IC) \ /* * Strict equality operators (`===` and `!==`). * * Pop two values, check whether they're equal, and push the boolean * result. This does not call user-defined methods and can't throw * (except possibly due to OOM while flattening a string). * * Implements: [Strict Equality Comparison][1]. * * [1]: https://tc39.es/ecma262/#sec-strict-equality-comparison * * Category: Expressions * Type: Binary operators * Operands: * Stack: lval, rval => (lval OP rval) */ \ MACRO(StrictEq, strict_eq, "===", 1, 2, 1, JOF_BYTE|JOF_IC) \ MACRO(StrictNe, strict_ne, "!==", 1, 2, 1, JOF_BYTE|JOF_IC) \ /* * Relative operators (`<`, `>`, `<=`, `>=`). * * Pop two values, compare them, and push the boolean result. The * comparison may perform conversions that call `.toString()`/`.valueOf()` * methods and can throw. * * Implements: [Relational Operators: Evaluation][1]. * * [1]: https://tc39.es/ecma262/#sec-relational-operators-runtime-semantics-evaluation * * Category: Expressions * Type: Binary operators * Operands: * Stack: lval, rval => (lval OP rval) */ \ MACRO(Lt, lt, "<", 1, 2, 1, JOF_BYTE|JOF_IC) \ MACRO(Gt, gt, ">", 1, 2, 1, JOF_BYTE|JOF_IC) \ MACRO(Le, le, "<=", 1, 2, 1, JOF_BYTE|JOF_IC) \ MACRO(Ge, ge, ">=", 1, 2, 1, JOF_BYTE|JOF_IC) \ /* * [The `instanceof` operator][1]. * * This throws a `TypeError` if `target` is not an object. It calls * `target[Symbol.hasInstance](value)` if the method exists. On success, * the result is always a boolean value. * * [1]: https://tc39.es/ecma262/#sec-instanceofoperator * * Category: Expressions * Type: Binary operators * Operands: * Stack: value, target => (value instanceof target) */ \ MACRO(Instanceof, instanceof, "instanceof", 1, 2, 1, JOF_BYTE|JOF_IC) \ /* * [The `in` operator][1]. * * Push `true` if `obj` has a property with the key `id`. Otherwise push `false`. * * This throws a `TypeError` if `obj` is not an object. This can fire * proxy hooks and can throw. On success, the result is always a boolean * value. * * [1]: https://tc39.es/ecma262/#sec-relational-operators-runtime-semantics-evaluation * * Category: Expressions * Type: Binary operators * Operands: * Stack: id, obj => (id in obj) */ \ MACRO(In, in_, "in", 1, 2, 1, JOF_BYTE|JOF_IC) \ /* * [Bitwise shift operators][1] (`<<`, `>>`, `>>>`). * * Pop two values, convert them to integers, perform a bitwise shift, and * push the result. * * Conversion can call `.toString()`/`.valueOf()` methods and can throw. * The result on success is always an Int32 or BigInt Value. * * [1]: https://tc39.es/ecma262/#sec-bitwise-shift-operators * * Category: Expressions * Type: Binary operators * Operands: * Stack: lval, rval => (lval OP rval) */ \ MACRO(Lsh, lsh, "<<", 1, 2, 1, JOF_BYTE|JOF_IC) \ MACRO(Rsh, rsh, ">>", 1, 2, 1, JOF_BYTE|JOF_IC) \ MACRO(Ursh, ursh, ">>>", 1, 2, 1, JOF_BYTE|JOF_IC) \ /* * [The binary `+` operator][1]. * * Pop two values, convert them to primitive values, add them, and push the * result. If both values are numeric, add them; if either is a * string, do string concatenation instead. * * The conversion can call `.toString()`/`.valueOf()` methods and can throw. * * [1]: https://tc39.es/ecma262/#sec-addition-operator-plus-runtime-semantics-evaluation * * Category: Expressions * Type: Binary operators * Operands: * Stack: lval, rval => (lval + rval) */ \ MACRO(Add, add, "+", 1, 2, 1, JOF_BYTE|JOF_IC) \ /* * [The binary `-` operator][1]. * * Pop two values, convert them to numeric values, subtract the top value * from the other one, and push the result. * * The conversion can call `.toString()`/`.valueOf()` methods and can * throw. On success, the result is always numeric. * * [1]: https://tc39.es/ecma262/#sec-subtraction-operator-minus-runtime-semantics-evaluation * * Category: Expressions * Type: Binary operators * Operands: * Stack: lval, rval => (lval - rval) */ \ MACRO(Sub, sub, "-", 1, 2, 1, JOF_BYTE|JOF_IC) \ /* * Add or subtract 1. * * `val` must already be a numeric value, such as the result of * `JSOp::ToNumeric`. * * Implements: [The `++` and `--` operators][1], step 3 of each algorithm. * * [1]: https://tc39.es/ecma262/#sec-postfix-increment-operator * * Category: Expressions * Type: Binary operators * Operands: * Stack: val => (val +/- 1) */ \ MACRO(Inc, inc, NULL, 1, 1, 1, JOF_BYTE|JOF_IC) \ MACRO(Dec, dec, NULL, 1, 1, 1, JOF_BYTE|JOF_IC) \ /* * [The multiplicative operators][1] (`*`, `/`, `%`). * * Pop two values, convert them to numeric values, do math, and push the * result. * * The conversion can call `.toString()`/`.valueOf()` methods and can * throw. On success, the result is always numeric. * * [1]: https://tc39.es/ecma262/#sec-multiplicative-operators-runtime-semantics-evaluation * * Category: Expressions * Type: Binary operators * Operands: * Stack: lval, rval => (lval OP rval) */ \ MACRO(Mul, mul, "*", 1, 2, 1, JOF_BYTE|JOF_IC) \ MACRO(Div, div, "/", 1, 2, 1, JOF_BYTE|JOF_IC) \ MACRO(Mod, mod, "%", 1, 2, 1, JOF_BYTE|JOF_IC) \ /* * [The exponentiation operator][1] (`**`). * * Pop two values, convert them to numeric values, do exponentiation, and * push the result. The top value is the exponent. * * The conversion can call `.toString()`/`.valueOf()` methods and can * throw. This throws a RangeError if both values are BigInts and the * exponent is negative. * * [1]: https://tc39.es/ecma262/#sec-exp-operator * * Category: Expressions * Type: Binary operators * Operands: * Stack: lval, rval => (lval ** rval) */ \ MACRO(Pow, pow, "**", 1, 2, 1, JOF_BYTE|JOF_IC) \ /* * Convert a value to a property key. * * Implements: [ToPropertyKey][1], except that if the result would be the * string representation of some integer in the range 0..2^31, we push the * corresponding Int32 value instead. This is because the spec insists that * array indices are strings, whereas for us they are integers. * * This is used for code like `++obj[index]`, which must do both a * `JSOp::GetElem` and a `JSOp::SetElem` with the same property key. Both * instructions would convert `index` to a property key for us, but the * spec says to convert it only once. * * The conversion can call `.toString()`/`.valueOf()` methods and can * throw. * * [1]: https://tc39.es/ecma262/#sec-topropertykey * * Category: Expressions * Type: Conversions * Operands: * Stack: propertyNameValue => propertyKey */ \ MACRO(ToPropertyKey, to_property_key, NULL, 1, 1, 1, JOF_BYTE|JOF_IC) \ /* * Convert a value to a numeric value (a Number or BigInt). * * Implements: [ToNumeric][1](val). * * Note: This is used to implement [`++` and `--`][2]. Surprisingly, it's * not possible to get the right behavior using `JSOp::Add` and `JSOp::Sub` * alone. For one thing, `JSOp::Add` sometimes does string concatenation, * while `++` always does numeric addition. More fundamentally, the result * of evaluating `x--` is ToNumeric(old value of `x`), a value that the * sequence `GetLocal "x"; One; Sub; SetLocal "x"` does not give us. * * [1]: https://tc39.es/ecma262/#sec-tonumeric * [2]: https://tc39.es/ecma262/#sec-postfix-increment-operator * * Category: Expressions * Type: Conversions * Operands: * Stack: val => ToNumeric(val) */ \ MACRO(ToNumeric, to_numeric, NULL, 1, 1, 1, JOF_BYTE|JOF_IC) \ /* * Convert a value to a string. * * Implements: [ToString][1](val). * * Note: This is used in code for template literals, like `${x}${y}`. Each * substituted value must be converted using ToString. `JSOp::Add` by itself * would do a slightly wrong kind of conversion (hint="number" rather than * hint="string"). * * [1]: https://tc39.es/ecma262/#sec-tostring * * Category: Expressions * Type: Conversions * Stack: val => ToString(val) */ \ MACRO(ToString, to_string, NULL, 1, 1, 1, JOF_BYTE) \ /* * Test whether the value on top of the stack is `NullValue` or * `UndefinedValue` and push the boolean result. * * Category: Expressions * Type: Other expressions * Operands: * Stack: val => val, IsNullOrUndefined(val) */ \ MACRO(IsNullOrUndefined, is_null_or_undefined, NULL, 1, 1, 2, JOF_BYTE) \ /* * Push the global `this` value. Not to be confused with the `globalThis` * property on the global. * * This must be used only in scopes where `this` refers to the global * `this`. * * Category: Expressions * Type: Other expressions * Operands: * Stack: => this */ \ MACRO(GlobalThis, global_this, NULL, 1, 0, 1, JOF_BYTE) \ /* * Push the global `this` value for non-syntactic scope. Not to be confused * with the `globalThis` property on the global. * * This must be used only in scopes where `this` refers to the global * `this`. * * Category: Expressions * Type: Other expressions * Operands: * Stack: => this */ \ MACRO(NonSyntacticGlobalThis, non_syntactic_global_this, NULL, 1, 0, 1, JOF_BYTE) \ /* * Push the value of `new.target`. * * The result is a constructor or `undefined`. * * This must be used only in non-arrow function scripts. * * Implements: [GetNewTarget][1]. * * [1]: https://tc39.es/ecma262/#sec-getnewtarget * * Category: Expressions * Type: Other expressions * Operands: * Stack: => new.target */ \ MACRO(NewTarget, new_target, NULL, 1, 0, 1, JOF_BYTE) \ /* * Dynamic import of the module specified by the string value on the top of * the stack. * * Implements: [Import Calls][1]. * * [1]: https://tc39.es/ecma262/#sec-import-calls * * Category: Expressions * Type: Other expressions * Operands: * Stack: moduleId, options => promise */ \ MACRO(DynamicImport, dynamic_import, NULL, 1, 2, 1, JOF_BYTE) \ /* * Push the `import.meta` object. * * This must be used only in module code. * * Category: Expressions * Type: Other expressions * Operands: * Stack: => import.meta */ \ MACRO(ImportMeta, import_meta, NULL, 1, 0, 1, JOF_BYTE) \ /* * Create and push a new object with no properties. * * Category: Objects * Type: Creating objects * Operands: * Stack: => obj */ \ MACRO(NewInit, new_init, NULL, 1, 0, 1, JOF_BYTE|JOF_IC) \ /* * Create and push a new object of a predetermined shape. * * The new object has the shape `script->getShape(shapeIndex)`. * Subsequent `InitProp` instructions must fill in all slots of the new * object before it is used in any other way. * * Category: Objects * Type: Creating objects * Operands: uint32_t shapeIndex * Stack: => obj */ \ MACRO(NewObject, new_object, NULL, 5, 0, 1, JOF_SHAPE|JOF_IC) \ /* * Push a preconstructed object. * * Going one step further than `JSOp::NewObject`, this instruction doesn't * just reuse the shape--it actually pushes the preconstructed object * `script->getObject(objectIndex)` right onto the stack. The object must * be a singleton `PlainObject` or `ArrayObject`. * * The spec requires that an *ObjectLiteral* or *ArrayLiteral* creates a * new object every time it's evaluated, so this instruction must not be * used anywhere it might be executed more than once. * * This may only be used in non-function run-once scripts. Care also must * be taken to not emit in loops or other constructs where it could run * more than once. * * Category: Objects * Type: Creating objects * Operands: uint32_t objectIndex * Stack: => obj */ \ MACRO(Object, object, NULL, 5, 0, 1, JOF_OBJECT) \ /* * Create and push a new ordinary object with the provided [[Prototype]]. * * This is used to create the `.prototype` object for derived classes. * * Category: Objects * Type: Creating objects * Operands: * Stack: proto => obj */ \ MACRO(ObjWithProto, obj_with_proto, NULL, 1, 1, 1, JOF_BYTE) \ /* * Define a data property on an object. * * `obj` must be an object. * * Implements: [CreateDataPropertyOrThrow][1] as used in * [PropertyDefinitionEvaluation][2] of regular and shorthand * *PropertyDefinition*s. * * [1]: https://tc39.es/ecma262/#sec-createdatapropertyorthrow * [2]: https://tc39.es/ecma262/#sec-object-initializer-runtime-semantics-propertydefinitionevaluation * * Category: Objects * Type: Defining properties * Operands: uint32_t nameIndex * Stack: obj, val => obj */ \ MACRO(InitProp, init_prop, NULL, 5, 2, 1, JOF_ATOM|JOF_PROP|JOF_PROPINIT|JOF_IC) \ /* * Like `JSOp::InitProp`, but define a non-enumerable property. * * This is used to define class methods. * * Implements: [PropertyDefinitionEvaluation][1] for methods, steps 3 and * 4, when *enumerable* is false. * * [1]: https://tc39.es/ecma262/#sec-method-definitions-runtime-semantics-propertydefinitionevaluation * * Category: Objects * Type: Defining properties * Operands: uint32_t nameIndex * Stack: obj, val => obj */ \ MACRO(InitHiddenProp, init_hidden_prop, NULL, 5, 2, 1, JOF_ATOM|JOF_PROP|JOF_PROPINIT|JOF_IC) \ /* * Like `JSOp::InitProp`, but define a non-enumerable, non-writable, * non-configurable property. * * This is used to define the `.prototype` property on classes. * * Implements: [MakeConstructor][1], step 8, when *writablePrototype* is * false. * * [1]: https://tc39.es/ecma262/#sec-makeconstructor * * Category: Objects * Type: Defining properties * Operands: uint32_t nameIndex * Stack: obj, val => obj */ \ MACRO(InitLockedProp, init_locked_prop, NULL, 5, 2, 1, JOF_ATOM|JOF_PROP|JOF_PROPINIT|JOF_IC) \ /* * Define a data property on `obj` with property key `id` and value `val`. * * `obj` must be an object. * * Implements: [CreateDataPropertyOrThrow][1]. This instruction is used for * object literals like `{0: val}` and `{[id]: val}`, and methods like * `*[Symbol.iterator]() {}`. * * `JSOp::InitHiddenElem` is the same but defines a non-enumerable property, * for class methods. * `JSOp::InitLockedElem` is the same but defines a non-enumerable, non-writable, non-configurable property, * for private class methods. * * [1]: https://tc39.es/ecma262/#sec-createdatapropertyorthrow * * Category: Objects * Type: Defining properties * Operands: * Stack: obj, id, val => obj */ \ MACRO(InitElem, init_elem, NULL, 1, 3, 1, JOF_BYTE|JOF_ELEM|JOF_PROPINIT|JOF_IC) \ MACRO(InitHiddenElem, init_hidden_elem, NULL, 1, 3, 1, JOF_BYTE|JOF_ELEM|JOF_PROPINIT|JOF_IC) \ MACRO(InitLockedElem, init_locked_elem, NULL, 1, 3, 1, JOF_BYTE|JOF_ELEM|JOF_PROPINIT|JOF_IC) \ /* * Define an accessor property on `obj` with the given `getter`. * `nameIndex` gives the property name. * * `obj` must be an object and `getter` must be a function. * * `JSOp::InitHiddenPropGetter` is the same but defines a non-enumerable * property, for getters in classes. * * Category: Objects * Type: Defining properties * Operands: uint32_t nameIndex * Stack: obj, getter => obj */ \ MACRO(InitPropGetter, init_prop_getter, NULL, 5, 2, 1, JOF_ATOM|JOF_PROP|JOF_PROPINIT) \ MACRO(InitHiddenPropGetter, init_hidden_prop_getter, NULL, 5, 2, 1, JOF_ATOM|JOF_PROP|JOF_PROPINIT) \ /* * Define an accessor property on `obj` with property key `id` and the given `getter`. * * This is used to implement getters like `get [id]() {}` or `get 0() {}`. * * `obj` must be an object and `getter` must be a function. * * `JSOp::InitHiddenElemGetter` is the same but defines a non-enumerable * property, for getters in classes. * * Category: Objects * Type: Defining properties * Operands: * Stack: obj, id, getter => obj */ \ MACRO(InitElemGetter, init_elem_getter, NULL, 1, 3, 1, JOF_BYTE|JOF_ELEM|JOF_PROPINIT) \ MACRO(InitHiddenElemGetter, init_hidden_elem_getter, NULL, 1, 3, 1, JOF_BYTE|JOF_ELEM|JOF_PROPINIT) \ /* * Define an accessor property on `obj` with the given `setter`. * * This is used to implement ordinary setters like `set foo(v) {}`. * * `obj` must be an object and `setter` must be a function. * * `JSOp::InitHiddenPropSetter` is the same but defines a non-enumerable * property, for setters in classes. * * Category: Objects * Type: Defining properties * Operands: uint32_t nameIndex * Stack: obj, setter => obj */ \ MACRO(InitPropSetter, init_prop_setter, NULL, 5, 2, 1, JOF_ATOM|JOF_PROP|JOF_PROPINIT) \ MACRO(InitHiddenPropSetter, init_hidden_prop_setter, NULL, 5, 2, 1, JOF_ATOM|JOF_PROP|JOF_PROPINIT) \ /* * Define an accesssor property on `obj` with property key `id` and the * given `setter`. * * This is used to implement setters with computed property keys or numeric * keys. * * `JSOp::InitHiddenElemSetter` is the same but defines a non-enumerable * property, for setters in classes. * * Category: Objects * Type: Defining properties * Operands: * Stack: obj, id, setter => obj */ \ MACRO(InitElemSetter, init_elem_setter, NULL, 1, 3, 1, JOF_BYTE|JOF_ELEM|JOF_PROPINIT) \ MACRO(InitHiddenElemSetter, init_hidden_elem_setter, NULL, 1, 3, 1, JOF_BYTE|JOF_ELEM|JOF_PROPINIT) \ /* * Get the value of the property `obj.name`. This can call getters and * proxy traps. * * Implements: [GetV][1], [GetValue][2] step 5. * * [1]: https://tc39.es/ecma262/#sec-getv * [2]: https://tc39.es/ecma262/#sec-getvalue * * Category: Objects * Type: Accessing properties * Operands: uint32_t nameIndex * Stack: obj => obj[name] */ \ MACRO(GetProp, get_prop, NULL, 5, 1, 1, JOF_ATOM|JOF_PROP|JOF_IC) \ /* * Get the value of the property `obj[key]`. * * Implements: [GetV][1], [GetValue][2] step 5. * * [1]: https://tc39.es/ecma262/#sec-getv * [2]: https://tc39.es/ecma262/#sec-getvalue * * Category: Objects * Type: Accessing properties * Operands: * Stack: obj, key => obj[key] */ \ MACRO(GetElem, get_elem, NULL, 1, 2, 1, JOF_BYTE|JOF_ELEM|JOF_IC) \ /* * Non-strict assignment to a property, `obj.name = val`. * * This throws a TypeError if `obj` is null or undefined. If it's a * primitive value, the property is set on ToObject(`obj`), typically with * no effect. * * Implements: [PutValue][1] step 6 for non-strict code. * * [1]: https://tc39.es/ecma262/#sec-putvalue * * Category: Objects * Type: Accessing properties * Operands: uint32_t nameIndex * Stack: obj, val => val */ \ MACRO(SetProp, set_prop, NULL, 5, 2, 1, JOF_ATOM|JOF_PROP|JOF_PROPSET|JOF_CHECKSLOPPY|JOF_IC) \ /* * Like `JSOp::SetProp`, but for strict mode code. Throw a TypeError if * `obj[key]` exists but is non-writable, if it's an accessor property with * no setter, or if `obj` is a primitive value. * * Category: Objects * Type: Accessing properties * Operands: uint32_t nameIndex * Stack: obj, val => val */ \ MACRO(StrictSetProp, strict_set_prop, NULL, 5, 2, 1, JOF_ATOM|JOF_PROP|JOF_PROPSET|JOF_CHECKSTRICT|JOF_IC) \ /* * Non-strict assignment to a property, `obj[key] = val`. * * Implements: [PutValue][1] step 6 for non-strict code. * * [1]: https://tc39.es/ecma262/#sec-putvalue * * Category: Objects * Type: Accessing properties * Operands: * Stack: obj, key, val => val */ \ MACRO(SetElem, set_elem, NULL, 1, 3, 1, JOF_BYTE|JOF_ELEM|JOF_PROPSET|JOF_CHECKSLOPPY|JOF_IC) \ /* * Like `JSOp::SetElem`, but for strict mode code. Throw a TypeError if * `obj[key]` exists but is non-writable, if it's an accessor property with * no setter, or if `obj` is a primitive value. * * Category: Objects * Type: Accessing properties * Operands: * Stack: obj, key, val => val */ \ MACRO(StrictSetElem, strict_set_elem, NULL, 1, 3, 1, JOF_BYTE|JOF_ELEM|JOF_PROPSET|JOF_CHECKSTRICT|JOF_IC) \ /* * Delete a property from `obj`. Push true on success, false if the * property existed but could not be deleted. This implements `delete * obj.name` in non-strict code. * * Throws if `obj` is null or undefined. Can call proxy traps. * * Implements: [`delete obj.propname`][1] step 5 in non-strict code. * * [1]: https://tc39.es/ecma262/#sec-delete-operator-runtime-semantics-evaluation * * Category: Objects * Type: Accessing properties * Operands: uint32_t nameIndex * Stack: obj => succeeded */ \ MACRO(DelProp, del_prop, NULL, 5, 1, 1, JOF_ATOM|JOF_PROP|JOF_CHECKSLOPPY) \ /* * Like `JSOp::DelProp`, but for strict mode code. Push `true` on success, * else throw a TypeError. * * Category: Objects * Type: Accessing properties * Operands: uint32_t nameIndex * Stack: obj => succeeded */ \ MACRO(StrictDelProp, strict_del_prop, NULL, 5, 1, 1, JOF_ATOM|JOF_PROP|JOF_CHECKSTRICT) \ /* * Delete the property `obj[key]` and push `true` on success, `false` * if the property existed but could not be deleted. * * This throws if `obj` is null or undefined. Can call proxy traps. * * Implements: [`delete obj[key]`][1] step 5 in non-strict code. * * [1]: https://tc39.es/ecma262/#sec-delete-operator-runtime-semantics-evaluation * * Category: Objects * Type: Accessing properties * Operands: * Stack: obj, key => succeeded */ \ MACRO(DelElem, del_elem, NULL, 1, 2, 1, JOF_BYTE|JOF_ELEM|JOF_CHECKSLOPPY) \ /* * Like `JSOp::DelElem, but for strict mode code. Push `true` on success, * else throw a TypeError. * * Category: Objects * Type: Accessing properties * Operands: * Stack: obj, key => succeeded */ \ MACRO(StrictDelElem, strict_del_elem, NULL, 1, 2, 1, JOF_BYTE|JOF_ELEM|JOF_CHECKSTRICT) \ /* * Push true if `obj` has an own property `id`. * * Note that `obj` is the top value, like `JSOp::In`. * * This opcode is not used for normal JS. Self-hosted code uses it by * calling the intrinsic `hasOwn(id, obj)`. For example, * `Object.prototype.hasOwnProperty` is implemented this way (see * js/src/builtin/Object.js). * * Category: Objects * Type: Accessing properties * Operands: * Stack: id, obj => (obj.hasOwnProperty(id)) */ \ MACRO(HasOwn, has_own, NULL, 1, 2, 1, JOF_BYTE|JOF_IC) \ /* * Push a bool representing the presence of private field id on obj. * May throw, depending on the ThrowCondition. * * Two arguments: * - throwCondition: One of the ThrowConditions defined in * ThrowMsgKind.h. Determines why (or if) this op will throw. * - msgKind: One of the ThrowMsgKinds defined in ThrowMsgKind.h, which * maps to one of the messages in js.msg. Note: It's not possible to * pass arguments to the message at the moment. * * Category: Objects * Type: Accessing properties * Operands: ThrowCondition throwCondition, ThrowMsgKind msgKind * Stack: obj, key => obj, key, (obj.hasOwnProperty(id)) */ \ MACRO(CheckPrivateField, check_private_field, NULL, 3, 2, 3, JOF_TWO_UINT8|JOF_CHECKSTRICT|JOF_IC) \ /* * Push a new private name. * * Category: Objects * Type: Accessing properties * Operands: uint32_t nameIndex * Stack: => private_name */ \ MACRO(NewPrivateName, new_private_name, NULL, 5, 0, 1, JOF_ATOM) \ /* * Push the SuperBase of the method `callee`. The SuperBase is * `callee.[[HomeObject]].[[GetPrototypeOf]]()`, the object where `super` * property lookups should begin. * * `callee` must be a function that has a HomeObject that's an object, * typically produced by `JSOp::Callee` or `JSOp::EnvCallee`. * * Implements: [GetSuperBase][1], except that instead of the environment, * the argument supplies the callee. * * [1]: https://tc39.es/ecma262/#sec-getsuperbase * * Category: Objects * Type: Super * Operands: * Stack: callee => superBase */ \ MACRO(SuperBase, super_base, NULL, 1, 1, 1, JOF_BYTE) \ /* * Get the value of `receiver.name`, starting the property search at `obj`. * In spec terms, `obj.[[Get]](name, receiver)`. * * Implements: [GetValue][1] for references created by [`super.name`][2]. * The `receiver` is `this` and `obj` is the SuperBase of the enclosing * method. * * [1]: https://tc39.es/ecma262/#sec-getvalue * [2]: https://tc39.es/ecma262/#sec-super-keyword-runtime-semantics-evaluation * * Category: Objects * Type: Super * Operands: uint32_t nameIndex * Stack: receiver, obj => super.name */ \ MACRO(GetPropSuper, get_prop_super, NULL, 5, 2, 1, JOF_ATOM|JOF_PROP|JOF_IC) \ /* * Get the value of `receiver[key]`, starting the property search at `obj`. * In spec terms, `obj.[[Get]](key, receiver)`. * * Implements: [GetValue][1] for references created by [`super[key]`][2] * (where the `receiver` is `this` and `obj` is the SuperBase of the enclosing * method); [`Reflect.get(obj, key, receiver)`][3]. * * [1]: https://tc39.es/ecma262/#sec-getvalue * [2]: https://tc39.es/ecma262/#sec-super-keyword-runtime-semantics-evaluation * [3]: https://tc39.es/ecma262/#sec-reflect.get * * Category: Objects * Type: Super * Operands: * Stack: receiver, key, obj => super[key] */ \ MACRO(GetElemSuper, get_elem_super, NULL, 1, 3, 1, JOF_BYTE|JOF_ELEM|JOF_IC) \ /* * Assign `val` to `receiver.name`, starting the search for an existing * property at `obj`. In spec terms, `obj.[[Set]](name, val, receiver)`. * * Implements: [PutValue][1] for references created by [`super.name`][2] in * non-strict code. The `receiver` is `this` and `obj` is the SuperBase of * the enclosing method. * * [1]: https://tc39.es/ecma262/#sec-putvalue * [2]: https://tc39.es/ecma262/#sec-super-keyword-runtime-semantics-evaluation * * Category: Objects * Type: Super * Operands: uint32_t nameIndex * Stack: receiver, obj, val => val */ \ MACRO(SetPropSuper, set_prop_super, NULL, 5, 3, 1, JOF_ATOM|JOF_PROP|JOF_PROPSET|JOF_CHECKSLOPPY) \ /* * Like `JSOp::SetPropSuper`, but for strict mode code. * * Category: Objects * Type: Super * Operands: uint32_t nameIndex * Stack: receiver, obj, val => val */ \ MACRO(StrictSetPropSuper, strict_set_prop_super, NULL, 5, 3, 1, JOF_ATOM|JOF_PROP|JOF_PROPSET|JOF_CHECKSTRICT) \ /* * Assign `val` to `receiver[key]`, strating the search for an existing * property at `obj`. In spec terms, `obj.[[Set]](key, val, receiver)`. * * Implements: [PutValue][1] for references created by [`super[key]`][2] in * non-strict code. The `receiver` is `this` and `obj` is the SuperBase of * the enclosing method. * * [1]: https://tc39.es/ecma262/#sec-putvalue * [2]: https://tc39.es/ecma262/#sec-super-keyword-runtime-semantics-evaluation * * Category: Objects * Type: Super * Operands: * Stack: receiver, key, obj, val => val */ \ MACRO(SetElemSuper, set_elem_super, NULL, 1, 4, 1, JOF_BYTE|JOF_ELEM|JOF_PROPSET|JOF_CHECKSLOPPY) \ /* * Like `JSOp::SetElemSuper`, but for strict mode code. * * Category: Objects * Type: Super * Operands: * Stack: receiver, key, obj, val => val */ \ MACRO(StrictSetElemSuper, strict_set_elem_super, NULL, 1, 4, 1, JOF_BYTE|JOF_ELEM|JOF_PROPSET|JOF_CHECKSTRICT) \ /* * Set up a for-in loop by pushing a `PropertyIteratorObject` over the * enumerable properties of `val`. * * Implements: [ForIn/OfHeadEvaluation][1] step 6, * [EnumerateObjectProperties][1]. (The spec refers to an "Iterator object" * with a `next` method, but notes that it "is never directly accessible" * to scripts. The object we use for this has no public methods.) * * If `val` is null or undefined, this pushes an empty iterator. * * The `iter` object pushed by this instruction must not be used or removed * from the stack except by `JSOp::MoreIter` and `JSOp::EndIter`, or by error * handling. * * The script's `JSScript::trynotes()` must mark the body of the `for-in` * loop, i.e. exactly those instructions that begin executing with `iter` * on the stack, starting with the next instruction (always * `JSOp::LoopHead`). Code must not jump into or out of this region: control * can enter only by executing `JSOp::Iter` and can exit only by executing a * `JSOp::EndIter` or by exception unwinding. (A `JSOp::EndIter` is always * emitted at the end of the loop, and extra copies are emitted on "exit * slides", where a `break`, `continue`, or `return` statement exits the * loop.) * * Typically a single try note entry marks the contiguous chunk of bytecode * from the instruction after `JSOp::Iter` to `JSOp::EndIter` (inclusive); * but if that range contains any instructions on exit slides, after a * `JSOp::EndIter`, then those must be correctly noted as *outside* the * loop. * * [1]: https://tc39.es/ecma262/#sec-runtime-semantics-forin-div-ofheadevaluation-tdznames-expr-iterationkind * [2]: https://tc39.es/ecma262/#sec-enumerate-object-properties * * Category: Objects * Type: Enumeration * Operands: * Stack: val => iter */ \ MACRO(Iter, iter, NULL, 1, 1, 1, JOF_BYTE|JOF_IC) \ /* * Get the next property name for a for-in loop. * * `iter` must be a `PropertyIteratorObject` produced by `JSOp::Iter`. This * pushes the property name for the next loop iteration, or * `MagicValue(JS_NO_ITER_VALUE)` if there are no more enumerable * properties to iterate over. The magic value must be used only by * `JSOp::IsNoIter` and `JSOp::EndIter`. * * Category: Objects * Type: Enumeration * Operands: * Stack: iter => iter, name */ \ MACRO(MoreIter, more_iter, NULL, 1, 1, 2, JOF_BYTE) \ /* * Test whether the value on top of the stack is * `MagicValue(JS_NO_ITER_VALUE)` and push the boolean result. * * Category: Objects * Type: Enumeration * Operands: * Stack: val => val, done */ \ MACRO(IsNoIter, is_no_iter, NULL, 1, 1, 2, JOF_BYTE) \ /* * Exit a for-in loop, closing the iterator. * * `iter` must be a `PropertyIteratorObject` pushed by `JSOp::Iter`. * * Category: Objects * Type: Enumeration * Operands: * Stack: iter, iterval => */ \ MACRO(EndIter, end_iter, NULL, 1, 2, 0, JOF_BYTE) \ /* * If the iterator object on top of the stack has a `return` method, * call that method. If the method exists but does not return an object, * and `kind` is not `CompletionKind::Throw`, throw a TypeError. (If * `kind` is `Throw`, the error we are already throwing takes precedence.) * * `iter` must be an object conforming to the [Iterator][1] interface. * * Implements: [IteratorClose][2] * * [1]: https://tc39.es/ecma262/#sec-iterator-interface * [2]: https://tc39.es/ecma262/#sec-iteratorclose * Category: Objects * Type: Iteration * Operands: CompletionKind kind * Stack: iter => */ \ MACRO(CloseIter, close_iter, NULL, 2, 1, 0, JOF_UINT8|JOF_IC) \ /* * Check that the top value on the stack is an object, and throw a * TypeError if not. `kind` is used only to generate an appropriate error * message. * * Implements: [GetIterator][1] step 5, [IteratorNext][2] step 3. Both * operations call a JS method which scripts can define however they want, * so they check afterwards that the method returned an object. * * [1]: https://tc39.es/ecma262/#sec-getiterator * [2]: https://tc39.es/ecma262/#sec-iteratornext * * Category: Objects * Type: Iteration * Operands: CheckIsObjectKind kind * Stack: result => result */ \ MACRO(CheckIsObj, check_is_obj, NULL, 2, 1, 1, JOF_UINT8) \ /* * Throw a TypeError if `val` is `null` or `undefined`. * * Implements: [RequireObjectCoercible][1]. But most instructions that * require an object will perform this check for us, so of the dozens of * calls to RequireObjectCoercible in the spec, we need this instruction * only for [destructuring assignment][2] and [initialization][3]. * * [1]: https://tc39.es/ecma262/#sec-requireobjectcoercible * [2]: https://tc39.es/ecma262/#sec-runtime-semantics-destructuringassignmentevaluation * [3]: https://tc39.es/ecma262/#sec-destructuring-binding-patterns-runtime-semantics-bindinginitialization * * Category: Objects * Type: Iteration * Operands: * Stack: val => val */ \ MACRO(CheckObjCoercible, check_obj_coercible, NULL, 1, 1, 1, JOF_BYTE) \ /* * Create and push an async iterator wrapping the sync iterator `iter`. * `next` should be `iter`'s `.next` method. * * Implements: [CreateAsyncToSyncIterator][1]. The spec says this operation * takes one argument, but that argument is a Record with two relevant * fields, `[[Iterator]]` and `[[NextMethod]]`. * * Used for `for await` loops. * * [1]: https://tc39.es/ecma262/#sec-createasyncfromsynciterator * * Category: Objects * Type: Iteration * Operands: * Stack: iter, next => asynciter */ \ MACRO(ToAsyncIter, to_async_iter, NULL, 1, 2, 1, JOF_BYTE) \ /* * Set the prototype of `obj`. * * `obj` must be an object. * * Implements: [B.3.1 __proto__ Property Names in Object Initializers][1], step 7.a. * * [1]: https://tc39.es/ecma262/#sec-__proto__-property-names-in-object-initializers * * Category: Objects * Type: SetPrototype * Operands: * Stack: obj, protoVal => obj */ \ MACRO(MutateProto, mutate_proto, NULL, 1, 2, 1, JOF_BYTE) \ /* * Create and push a new Array object with the given `length`, * preallocating enough memory to hold that many elements. * * Category: Objects * Type: Array literals * Operands: uint32_t length * Stack: => array */ \ MACRO(NewArray, new_array, NULL, 5, 0, 1, JOF_UINT32|JOF_IC) \ /* * Initialize an array element `array[index]` with value `val`. * * `val` may be `MagicValue(JS_ELEMENTS_HOLE)` pushed by `JSOp::Hole`. * * This never calls setters or proxy traps. * * `array` must be an Array object created by `JSOp::NewArray` with length > * `index`, and never used except by `JSOp::InitElemArray`. * * Implements: [ArrayAccumulation][1], the third algorithm, step 4, in the * common case where *nextIndex* is known. * * [1]: https://tc39.es/ecma262/#sec-runtime-semantics-arrayaccumulation * * Category: Objects * Type: Array literals * Operands: uint32_t index * Stack: array, val => array */ \ MACRO(InitElemArray, init_elem_array, NULL, 5, 2, 1, JOF_UINT32|JOF_ELEM|JOF_PROPINIT) \ /* * Initialize an array element `array[index++]` with value `val`. * * `val` may be `MagicValue(JS_ELEMENTS_HOLE)` pushed by `JSOp::Hole`. If it * is, no element is defined, but the array length and the stack value * `index` are still incremented. * * This never calls setters or proxy traps. * * `array` must be an Array object created by `JSOp::NewArray` and never used * except by `JSOp::InitElemArray` and `JSOp::InitElemInc`. * * `index` must be an integer, `0 <= index <= INT32_MAX`. If `index` is * `INT32_MAX`, this throws a RangeError. Unlike `InitElemArray`, it is not * necessary that the `array` length > `index`. * * This instruction is used when an array literal contains a * *SpreadElement*. In `[a, ...b, c]`, `InitElemArray 0` is used to put * `a` into the array, but `InitElemInc` is used for the elements of `b` * and for `c`. * * Implements: Several steps in [ArrayAccumulation][1] that call * CreateDataProperty, set the array length, and/or increment *nextIndex*. * * [1]: https://tc39.es/ecma262/#sec-runtime-semantics-arrayaccumulation * * Category: Objects * Type: Array literals * Operands: * Stack: array, index, val => array, (index + 1) */ \ MACRO(InitElemInc, init_elem_inc, NULL, 1, 3, 2, JOF_BYTE|JOF_ELEM|JOF_PROPINIT|JOF_IC) \ /* * Push `MagicValue(JS_ELEMENTS_HOLE)`, representing an *Elision* in an * array literal (like the missing property 0 in the array `[, 1]`). * * This magic value must be used only by `JSOp::InitElemArray` or * `JSOp::InitElemInc`. * * Category: Objects * Type: Array literals * Operands: * Stack: => hole */ \ MACRO(Hole, hole, NULL, 1, 0, 1, JOF_BYTE) \ /* * Clone and push a new RegExp object. * * Implements: [Evaluation for *RegularExpressionLiteral*][1]. * * [1]: https://tc39.es/ecma262/#sec-regular-expression-literals-runtime-semantics-evaluation * * Category: Objects * Type: RegExp literals * Operands: uint32_t regexpIndex * Stack: => regexp */ \ MACRO(RegExp, reg_exp, NULL, 5, 0, 1, JOF_REGEXP) \ /* * Initialize a new record, preallocating `length` memory slots. `length` can still grow * if needed, for example when using the spread operator. * * Implements: [RecordLiteral Evaluation][1] step 1. * * [1]: https://tc39.es/proposal-record-tuple/#sec-record-initializer-runtime-semantics-evaluation * * Category: Compound primitives * Type: Record literals * Operands: uint32_t length * Stack: => rval */ \ IF_RECORD_TUPLE(MACRO(InitRecord, init_record, NULL, 5, 0, 1, JOF_UINT32)) \ /* * Add the last element in the stack to the preceding tuple. * * Implements: [AddPropertyIntoRecordEntriesList][1]. * * [1]: https://tc39.es/proposal-record-tuple/#sec-addpropertyintorecordentrieslist * * Category: Compound primitives * Type: Record literals * Operands: * Stack: record, key, value => record */ \ IF_RECORD_TUPLE(MACRO(AddRecordProperty, add_record_property, NULL, 1, 3, 1, JOF_BYTE)) \ /* * Add the last element in the stack to the preceding tuple. * * Implements: [RecordPropertyDefinitionEvaluation][1] for * RecordPropertyDefinition : ... AssignmentExpression * * [1]: https://tc39.es/proposal-record-tuple/#sec-addpropertyintorecordentrieslist * * Category: Compound primitives * Type: Record literals * Operands: * Stack: record, value => record */ \ IF_RECORD_TUPLE(MACRO(AddRecordSpread, add_record_spread, NULL, 1, 2, 1, JOF_BYTE)) \ /* * Mark a record as "initialized", going from "write-only" mode to * "read-only" mode. * * Category: Compound primitives * Type: Record literals * Operands: * Stack: record => record */ \ IF_RECORD_TUPLE(MACRO(FinishRecord, finish_record, NULL, 1, 1, 1, JOF_BYTE)) \ /* * Initialize a new tuple, preallocating `length` memory slots. `length` can still grow * if needed, for example when using the spread operator. * * Implements: [TupleLiteral Evaluation][1] step 1. * * [1]: https://tc39.es/proposal-record-tuple/#sec-tuple-initializer-runtime-semantics-evaluation * * Category: Compound primitives * Type: Tuple literals * Operands: uint32_t length * Stack: => rval */ \ IF_RECORD_TUPLE(MACRO(InitTuple, init_tuple, NULL, 5, 0, 1, JOF_UINT32)) \ /* * Add the last element in the stack to the preceding tuple. * * Implements: [AddValueToTupleSequenceList][1]. * * [1]: https://tc39.es/proposal-record-tuple/#sec-addvaluetotuplesequencelist * * Category: Compound primitives * Type: Tuple literals * Operands: * Stack: tuple, element => tuple */ \ IF_RECORD_TUPLE(MACRO(AddTupleElement, add_tuple_element, NULL, 1, 2, 1, JOF_BYTE)) \ /* * Mark a tuple as "initialized", going from "write-only" mode to * "read-only" mode. * * Category: Compound primitives * Type: Tuple literals * Operands: * Stack: tuple => tuple */ \ IF_RECORD_TUPLE(MACRO(FinishTuple, finish_tuple, NULL, 1, 1, 1, JOF_BYTE)) \ /* * Push a new function object. * * The new function inherits the current environment chain. * * Used to create most JS functions. Notable exceptions are derived or * default class constructors. * * Implements: [InstantiateFunctionObject][1], [Evaluation for * *FunctionExpression*][2], and so on. * * [1]: https://tc39.es/ecma262/#sec-function-definitions-runtime-semantics-instantiatefunctionobject * [2]: https://tc39.es/ecma262/#sec-function-definitions-runtime-semantics-evaluation * * Category: Functions * Type: Creating functions * Operands: uint32_t funcIndex * Stack: => fn */ \ MACRO(Lambda, lambda, NULL, 5, 0, 1, JOF_OBJECT|JOF_USES_ENV) \ /* * Set the name of a function. * * `fun` must be a function object. `name` must be a string, Int32 value, * or symbol (like the result of `JSOp::ToId`). * * Implements: [SetFunctionName][1], used e.g. to name methods with * computed property names. * * [1]: https://tc39.es/ecma262/#sec-setfunctionname * * Category: Functions * Type: Creating functions * Operands: FunctionPrefixKind prefixKind * Stack: fun, name => fun */ \ MACRO(SetFunName, set_fun_name, NULL, 2, 2, 1, JOF_UINT8) \ /* * Initialize the home object for functions with super bindings. * * `fun` must be a method, getter, or setter, so that it has a * [[HomeObject]] slot. `homeObject` must be a plain object or (for static * methods) a constructor. * * Category: Functions * Type: Creating functions * Operands: * Stack: fun, homeObject => fun */ \ MACRO(InitHomeObject, init_home_object, NULL, 1, 2, 1, JOF_BYTE) \ /* * Throw a TypeError if `baseClass` isn't either `null` or a constructor. * * Implements: [ClassDefinitionEvaluation][1] step 6.f. * * [1]: https://tc39.es/ecma262/#sec-runtime-semantics-classdefinitionevaluation * * Category: Functions * Type: Creating constructors * Operands: * Stack: baseClass => baseClass */ \ MACRO(CheckClassHeritage, check_class_heritage, NULL, 1, 1, 1, JOF_BYTE) \ /* * Like `JSOp::Lambda`, but using `proto` as the new function's * `[[Prototype]]` (or `%FunctionPrototype%` if `proto` is `null`). * * `proto` must be either a constructor or `null`. We use * `JSOp::CheckClassHeritage` to check. * * This is used to create the constructor for a derived class. * * Implements: [ClassDefinitionEvaluation][1] steps 6.e.ii, 6.g.iii, and * 12 for derived classes. * * [1]: https://tc39.es/ecma262/#sec-runtime-semantics-classdefinitionevaluation * * Category: Functions * Type: Creating constructors * Operands: uint32_t funcIndex * Stack: proto => obj */ \ MACRO(FunWithProto, fun_with_proto, NULL, 5, 1, 1, JOF_OBJECT|JOF_USES_ENV) \ /* * Pushes the current global's %BuiltinObject%. * * `kind` must be a valid `BuiltinObjectKind` (and must not be * `BuiltinObjectKind::None`). * * Category: Objects * Type: Built-in objects * Operands: uint8_t kind * Stack: => %BuiltinObject% */ \ MACRO(BuiltinObject, builtin_object, NULL, 2, 0, 1, JOF_UINT8) \ /* * Invoke `callee` with `this` and `args`, and push the return value. Throw * a TypeError if `callee` isn't a function. * * `JSOp::CallContent` is for `callContentFunction` in self-hosted JS, and * this is for handling it differently in debugger's `onNativeCall` hook. * `onNativeCall` hook disables all JITs, and `JSOp::CallContent` is * treated exactly the same as `JSOP::Call` in JIT. * * `JSOp::CallIter` is used for implicit calls to @@iterator methods, to * ensure error messages are formatted with `JSMSG_NOT_ITERABLE` ("x is not * iterable") rather than `JSMSG_NOT_FUNCTION` ("x[Symbol.iterator] is not * a function"). The `argc` operand must be 0 for this variation. * * `JSOp::CallContentIter` is `JSOp::CallContent` variant of * `JSOp::CallIter`. * * `JSOp::CallIgnoresRv` hints to the VM that the return value is ignored. * This allows alternate faster implementations to be used that avoid * unnecesary allocations. * * Implements: [EvaluateCall][1] steps 4, 5, and 7. * * [1]: https://tc39.es/ecma262/#sec-evaluatecall * * Category: Functions * Type: Calls * Operands: uint16_t argc * Stack: callee, this, args[0], ..., args[argc-1] => rval */ \ MACRO(Call, call, NULL, 3, -1, 1, JOF_ARGC|JOF_INVOKE|JOF_IC) \ MACRO(CallContent, call_content, NULL, 3, -1, 1, JOF_ARGC|JOF_INVOKE|JOF_IC) \ MACRO(CallIter, call_iter, NULL, 3, -1, 1, JOF_ARGC|JOF_INVOKE|JOF_IC) \ MACRO(CallContentIter, call_content_iter, NULL, 3, -1, 1, JOF_ARGC|JOF_INVOKE|JOF_IC) \ MACRO(CallIgnoresRv, call_ignores_rv, NULL, 3, -1, 1, JOF_ARGC|JOF_INVOKE|JOF_IC) \ /* * Like `JSOp::Call`, but the arguments are provided in an array rather than * a span of stack slots. Used to implement spread-call syntax: * `f(...args)`. * * `args` must be an Array object containing the actual arguments. The * array must be packed (dense and free of holes; see IsPackedArray). * This can be ensured by creating the array with `JSOp::NewArray` and * populating it using `JSOp::InitElemArray`. * * Category: Functions * Type: Calls * Operands: * Stack: callee, this, args => rval */ \ MACRO(SpreadCall, spread_call, NULL, 1, 3, 1, JOF_BYTE|JOF_INVOKE|JOF_SPREAD|JOF_IC) \ /* * Push an array object that can be passed directly as the `args` argument * to `JSOp::SpreadCall`. If the operation can't be optimized, push * `undefined` instead. * * This instruction and the branch around the iterator loop are emitted * only when `iterable` is the sole argument in a call, as in `f(...arr)`. * * See `js::OptimizeSpreadCall`. * * Category: Functions * Type: Calls * Operands: * Stack: iterable => array_or_undefined */ \ MACRO(OptimizeSpreadCall, optimize_spread_call, NULL, 1, 1, 1, JOF_BYTE|JOF_IC) \ /* * Perform a direct eval in the current environment if `callee` is the * builtin `eval` function, otherwise follow same behaviour as `JSOp::Call`. * * All direct evals use one of the JSOp::*Eval instructions here and these * opcodes are only used when the syntactic conditions for a direct eval * are met. If the builtin `eval` function is called though other means, it * becomes an indirect eval. * * Direct eval causes all bindings in *enclosing* non-global scopes to be * marked "aliased". The optimization that puts bindings in stack slots has * to prove that the bindings won't need to be captured by closures or * accessed using `JSOp::{Get,Bind,Set,Del}Name` instructions. Direct eval * makes that analysis impossible. * * The instruction immediately following any `JSOp::*Eval` instruction must * be `JSOp::Lineno`. * * Implements: [Function Call Evaluation][1], steps 5-7 and 9, when the * syntactic critera for direct eval in step 6 are all met. * * [1]: https://tc39.es/ecma262/#sec-function-calls-runtime-semantics-evaluation * * Category: Functions * Type: Calls * Operands: uint16_t argc * Stack: callee, this, args[0], ..., args[argc-1] => rval */ \ MACRO(Eval, eval, NULL, 3, -1, 1, JOF_ARGC|JOF_INVOKE|JOF_CHECKSLOPPY|JOF_IC) \ /* * Spread-call variant of `JSOp::Eval`. * * See `JSOp::SpreadCall` for restrictions on `args`. * * Category: Functions * Type: Calls * Operands: * Stack: callee, this, args => rval */ \ MACRO(SpreadEval, spread_eval, NULL, 1, 3, 1, JOF_BYTE|JOF_INVOKE|JOF_SPREAD|JOF_CHECKSLOPPY|JOF_IC) \ /* * Like `JSOp::Eval`, but for strict mode code. * * Category: Functions * Type: Calls * Operands: uint16_t argc * Stack: evalFn, this, args[0], ..., args[argc-1] => rval */ \ MACRO(StrictEval, strict_eval, NULL, 3, -1, 1, JOF_ARGC|JOF_INVOKE|JOF_CHECKSTRICT|JOF_IC) \ /* * Spread-call variant of `JSOp::StrictEval`. * * See `JSOp::SpreadCall` for restrictions on `args`. * * Category: Functions * Type: Calls * Operands: * Stack: callee, this, args => rval */ \ MACRO(StrictSpreadEval, strict_spread_eval, NULL, 1, 3, 1, JOF_BYTE|JOF_INVOKE|JOF_SPREAD|JOF_CHECKSTRICT|JOF_IC) \ /* * Push the implicit `this` value for an unqualified function call, like * `foo()`. `nameIndex` gives the name of the function we're calling. * * The result is always `undefined` except when the name refers to a `with` * binding. For example, in `with (date) { getFullYear(); }`, the * implicit `this` passed to `getFullYear` is `date`, not `undefined`. * * This walks the run-time environment chain looking for the environment * record that contains the function. If the function call definitely * refers to a local binding, use `JSOp::Undefined`. * * Implements: [EvaluateCall][1] step 1.b. But not entirely correctly. * See [bug 1166408][2]. * * [1]: https://tc39.es/ecma262/#sec-evaluatecall * [2]: https://bugzilla.mozilla.org/show_bug.cgi?id=1166408 * * Category: Functions * Type: Calls * Operands: uint32_t nameIndex * Stack: => this */ \ MACRO(ImplicitThis, implicit_this, "", 5, 0, 1, JOF_ATOM|JOF_USES_ENV) \ /* * Push the call site object for a tagged template call. * * `script->getObject(objectIndex)` is the call site object. * * The call site object will already have the `.raw` property defined on it * and will be frozen. * * Category: Functions * Type: Calls * Operands: uint32_t objectIndex * Stack: => callSiteObj */ \ MACRO(CallSiteObj, call_site_obj, NULL, 5, 0, 1, JOF_OBJECT) \ /* * Push `MagicValue(JS_IS_CONSTRUCTING)`. * * This magic value is a required argument to the `JSOp::New` and * `JSOp::SuperCall` instructions and must not be used any other way. * * Category: Functions * Type: Calls * Operands: * Stack: => JS_IS_CONSTRUCTING */ \ MACRO(IsConstructing, is_constructing, NULL, 1, 0, 1, JOF_BYTE) \ /* * Invoke `callee` as a constructor with `args` and `newTarget`, and push * the return value. Throw a TypeError if `callee` isn't a constructor. * * `isConstructing` must be the value pushed by `JSOp::IsConstructing`. * * `JSOp::SuperCall` behaves exactly like `JSOp::New`, but is used for * *SuperCall* expressions, to allow JITs to distinguish them from `new` * expressions. * * `JSOp::NewContent` is for `constructContentFunction` in self-hosted JS. * See the comment for `JSOp::CallContent` for more details. * * Implements: [EvaluateConstruct][1] steps 7 and 8. * * [1]: https://tc39.es/ecma262/#sec-evaluatenew * * Category: Functions * Type: Calls * Operands: uint16_t argc * Stack: callee, isConstructing, args[0], ..., args[argc-1], newTarget => rval */ \ MACRO(New, new_, NULL, 3, -1, 1, JOF_ARGC|JOF_INVOKE|JOF_CONSTRUCT|JOF_IC) \ MACRO(NewContent, new_content, NULL, 3, -1, 1, JOF_ARGC|JOF_INVOKE|JOF_CONSTRUCT|JOF_IC) \ MACRO(SuperCall, super_call, NULL, 3, -1, 1, JOF_ARGC|JOF_INVOKE|JOF_CONSTRUCT|JOF_IC) \ /* * Spread-call variant of `JSOp::New`. * * Invokes `callee` as a constructor with `args` and `newTarget`, and * pushes the return value onto the stack. * * `isConstructing` must be the value pushed by `JSOp::IsConstructing`. * See `JSOp::SpreadCall` for restrictions on `args`. * * `JSOp::SpreadSuperCall` behaves exactly like `JSOp::SpreadNew`, but is * used for *SuperCall* expressions. * * Category: Functions * Type: Calls * Operands: * Stack: callee, isConstructing, args, newTarget => rval */ \ MACRO(SpreadNew, spread_new, NULL, 1, 4, 1, JOF_BYTE|JOF_INVOKE|JOF_CONSTRUCT|JOF_SPREAD|JOF_IC) \ MACRO(SpreadSuperCall, spread_super_call, NULL, 1, 4, 1, JOF_BYTE|JOF_INVOKE|JOF_CONSTRUCT|JOF_SPREAD|JOF_IC) \ /* * Push the prototype of `callee` in preparation for calling `super()`. * * `callee` must be a derived class constructor. * * Implements: [GetSuperConstructor][1], steps 4-7. * * [1]: https://tc39.es/ecma262/#sec-getsuperconstructor * * Category: Functions * Type: Calls * Operands: * Stack: callee => superFun */ \ MACRO(SuperFun, super_fun, NULL, 1, 1, 1, JOF_BYTE) \ /* * Throw a ReferenceError if `thisval` is not * `MagicValue(JS_UNINITIALIZED_LEXICAL)`. Used in derived class * constructors to prohibit calling `super` more than once. * * Implements: [BindThisValue][1], step 3. * * [1]: https://tc39.es/ecma262/#sec-bindthisvalue * * Category: Functions * Type: Calls * Operands: * Stack: thisval => thisval */ \ MACRO(CheckThisReinit, check_this_reinit, NULL, 1, 1, 1, JOF_BYTE) \ /* * Create and push a generator object for the current frame. * * This instruction must appear only in scripts for generators, async * functions, and async generators. There must not already be a generator * object for the current frame (that is, this instruction must execute at * most once per generator or async call). * * Category: Functions * Type: Generators and async functions * Operands: * Stack: => gen */ \ MACRO(Generator, generator, NULL, 1, 0, 1, JOF_BYTE|JOF_USES_ENV) \ /* * Suspend the current generator and return to the caller. * * When a generator is called, its script starts running, like any other JS * function, because [FunctionDeclarationInstantation][1] and other * [generator object setup][2] are implemented mostly in bytecode. However, * the *FunctionBody* of the generator is not supposed to start running * until the first `.next()` call, so after setup the script suspends * itself: the "initial yield". * * Later, when resuming execution, `rval`, `gen` and `resumeKind` will * receive the values passed in by `JSOp::Resume`. `resumeKind` is the * `GeneratorResumeKind` stored as an Int32 value. * * This instruction must appear only in scripts for generators and async * generators. `gen` must be the generator object for the current frame. It * must not have been previously suspended. The resume point indicated by * `resumeIndex` must be the next instruction in the script, which must be * `AfterYield`. * * Implements: [GeneratorStart][3], steps 4-7. * * [1]: https://tc39.es/ecma262/#sec-functiondeclarationinstantiation * [2]: https://tc39.es/ecma262/#sec-generator-function-definitions-runtime-semantics-evaluatebody * [3]: https://tc39.es/ecma262/#sec-generatorstart * * Category: Functions * Type: Generators and async functions * Operands: uint24_t resumeIndex * Stack: gen => rval, gen, resumeKind */ \ MACRO(InitialYield, initial_yield, NULL, 4, 1, 3, JOF_RESUMEINDEX) \ /* * Bytecode emitted after `yield` expressions. This is useful for the * Debugger and `AbstractGeneratorObject::isAfterYieldOrAwait`. It's * treated as jump target op so that the Baseline Interpreter can * efficiently restore the frame's interpreterICEntry when resuming a * generator. * * The preceding instruction in the script must be `Yield`, `InitialYield`, * or `Await`. * * Category: Functions * Type: Generators and async functions * Operands: uint32_t icIndex * Stack: => */ \ MACRO(AfterYield, after_yield, NULL, 5, 0, 0, JOF_ICINDEX) \ /* * Suspend and close the current generator, async function, or async * generator. * * `gen` must be the generator object for the current frame. * * If the current function is a non-async generator, then the value in the * frame's return value slot is returned to the caller. It should be an * object of the form `{value: returnValue, done: true}`. * * If the current function is an async function or async generator, the * frame's return value slot must contain the current frame's result * promise, which must already be resolved or rejected. * * Category: Functions * Type: Generators and async functions * Operands: * Stack: gen => */ \ MACRO(FinalYieldRval, final_yield_rval, NULL, 1, 1, 0, JOF_BYTE) \ /* * Suspend execution of the current generator or async generator, returning * `rval1`. * * For non-async generators, `rval1` should be an object of the form * `{value: valueToYield, done: true}`. For async generators, `rval1` * should be the value to yield, and the caller is responsible for creating * the iterator result object (under `js::AsyncGeneratorYield`). * * This instruction must appear only in scripts for generators and async * generators. `gen` must be the generator object for the current stack * frame. The resume point indicated by `resumeIndex` must be the next * instruction in the script, which must be `AfterYield`. * * When resuming execution, `rval2`, `gen` and `resumeKind` receive the * values passed in by `JSOp::Resume`. * * Implements: [GeneratorYield][1] and [AsyncGeneratorYield][2]. * * [1]: https://tc39.es/ecma262/#sec-generatoryield * [2]: https://tc39.es/ecma262/#sec-asyncgeneratoryield * * Category: Functions * Type: Generators and async functions * Operands: uint24_t resumeIndex * Stack: rval1, gen => rval2, gen, resumeKind */ \ MACRO(Yield, yield, NULL, 4, 2, 3, JOF_RESUMEINDEX) \ /* * Pushes a boolean indicating whether the top of the stack is * `MagicValue(JS_GENERATOR_CLOSING)`. * * Category: Functions * Type: Generators and async functions * Operands: * Stack: val => val, res */ \ MACRO(IsGenClosing, is_gen_closing, NULL, 1, 1, 2, JOF_BYTE) \ /* * Arrange for this async function to resume asynchronously when `value` * becomes resolved. * * This is the last thing an async function does before suspending for an * `await` expression. It coerces the awaited `value` to a promise and * effectively calls `.then()` on it, passing handler functions that will * resume this async function call later. See `js::AsyncFunctionAwait`. * * This instruction must appear only in non-generator async function * scripts. `gen` must be the internal generator object for the current * frame. After this instruction, the script should suspend itself with * `Await` (rather than exiting any other way). * * The result `promise` is the async function's result promise, * `gen->as().promise()`. * * Implements: [Await][1], steps 2-9. * * [1]: https://tc39.github.io/ecma262/#await * * Category: Functions * Type: Generators and async functions * Operands: * Stack: value, gen => promise */ \ MACRO(AsyncAwait, async_await, NULL, 1, 2, 1, JOF_BYTE) \ /* * Resolve or reject the current async function's result promise with * 'valueOrReason'. * * This instruction must appear only in non-generator async function * scripts. `gen` must be the internal generator object for the current * frame. This instruction must run at most once per async function call, * as resolving/rejecting an already resolved/rejected promise is not * permitted. * * The result `promise` is the async function's result promise, * `gen->as().promise()`. * * Implements: [AsyncFunctionStart][1], step 4.d.i. and 4.e.i. * * [1]: https://tc39.es/ecma262/#sec-async-functions-abstract-operations-async-function-start * * Category: Functions * Type: Generators and async functions * Operands: AsyncFunctionResolveKind fulfillOrReject * Stack: valueOrReason, gen => promise */ \ MACRO(AsyncResolve, async_resolve, NULL, 2, 2, 1, JOF_UINT8) \ /* * Suspend the current frame for an `await` expression. * * This instruction must appear only in scripts for async functions and * async generators. `gen` must be the internal generator object for the * current frame. * * This returns `promise` to the caller. Later, when this async call is * resumed, `resolved`, `gen` and `resumeKind` receive the values passed in * by `JSOp::Resume`, and execution continues at the next instruction, * which must be `AfterYield`. * * This instruction is used in two subtly different ways. * * 1. In async functions: * * ... # valueToAwait * GetAliasedVar ".generator" # valueToAwait gen * AsyncAwait # resultPromise * GetAliasedVar ".generator" # resultPromise gen * Await # resolved gen resumeKind * AfterYield * * `AsyncAwait` arranges for this frame to be resumed later and pushes * its result promise. `Await` then suspends the frame and removes it * from the stack, returning the result promise to the caller. (If this * async call hasn't awaited before, the caller may be user code. * Otherwise, the caller is self-hosted code using `resumeGenerator`.) * * 2. In async generators: * * ... # valueToAwait * GetAliasedVar ".generator" # valueToAwait gen * Await # resolved gen resumeKind * AfterYield * * `AsyncAwait` is not used, so (1) the value returned to the caller by * `Await` is `valueToAwait`, not `resultPromise`; and (2) the caller * is responsible for doing the async-generator equivalent of * `AsyncAwait` (namely, `js::AsyncGeneratorAwait`, called from * `js::AsyncGeneratorResume` after `js::CallSelfHostedFunction` * returns). * * Implements: [Await][1], steps 10-12. * * [1]: https://tc39.es/ecma262/#await * * Category: Functions * Type: Generators and async functions * Operands: uint24_t resumeIndex * Stack: promise, gen => resolved, gen, resumeKind */ \ MACRO(Await, await, NULL, 4, 2, 3, JOF_RESUMEINDEX) \ /* * Test if the re-entry to the microtask loop may be skipped. * * This is part of an optimization for `await` expressions. Programs very * often await values that aren't promises, or promises that are already * resolved. We can then sometimes skip suspending the current frame and * returning to the microtask loop. If the circumstances permit the * optimization, `CanSkipAwait` pushes true if the optimization is allowed, * and false otherwise. * * Category: Functions * Type: Generators and async functions * Operands: * Stack: value => value, can_skip */ \ MACRO(CanSkipAwait, can_skip_await, NULL, 1, 1, 2, JOF_BYTE) \ /* * Potentially extract an awaited value, if the await is skippable * * If re-entering the microtask loop is skippable (as checked by CanSkipAwait) * if can_skip is true, `MaybeExtractAwaitValue` replaces `value` with the result of the * `await` expression (unwrapping the resolved promise, if any). Otherwise, value remains * as is. * * In both cases, can_skip remains the same. * * Category: Functions * Type: Generators and async functions * Operands: * Stack: value, can_skip => value_or_resolved, can_skip */ \ MACRO(MaybeExtractAwaitValue, maybe_extract_await_value, NULL, 1, 2, 2, JOF_BYTE) \ /* * Pushes one of the GeneratorResumeKind values as Int32Value. * * Category: Functions * Type: Generators and async functions * Operands: GeneratorResumeKind resumeKind (encoded as uint8_t) * Stack: => resumeKind */ \ MACRO(ResumeKind, resume_kind, NULL, 2, 0, 1, JOF_UINT8) \ /* * Handle Throw and Return resumption. * * `gen` must be the generator object for the current frame. `resumeKind` * must be a `GeneratorResumeKind` stored as an `Int32` value. If it is * `Next`, continue to the next instruction. If `resumeKind` is `Throw` or * `Return`, these completions are handled by throwing an exception. See * `GeneratorThrowOrReturn`. * * Category: Functions * Type: Generators and async functions * Operands: * Stack: rval, gen, resumeKind => rval */ \ MACRO(CheckResumeKind, check_resume_kind, NULL, 1, 3, 1, JOF_BYTE) \ /* * Resume execution of a generator, async function, or async generator. * * This behaves something like a call instruction. It pushes a stack frame * (the one saved when `gen` was suspended, rather than a fresh one) and * runs instructions in it. Once `gen` returns or yields, its return value * is pushed to this frame's stack and execution continues in this script. * * This instruction is emitted only for the `resumeGenerator` self-hosting * intrinsic. It is used in the implementation of * `%GeneratorPrototype%.next`, `.throw`, and `.return`. * * `gen` must be a suspended generator object. `resumeKind` must be in * range for `GeneratorResumeKind`. * * Category: Functions * Type: Generators and async functions * Operands: * Stack: gen, val, resumeKind => rval */ \ MACRO(Resume, resume, NULL, 1, 3, 1, JOF_BYTE|JOF_INVOKE) \ /* * No-op instruction marking the target of a jump instruction. * * This instruction and a few others (see `js::BytecodeIsJumpTarget`) are * jump target instructions. The Baseline Interpreter uses these * instructions to sync the frame's `interpreterICEntry` after a jump. Ion * uses them to find block boundaries when translating bytecode to MIR. * * Category: Control flow * Type: Jump targets * Operands: uint32_t icIndex * Stack: => */ \ MACRO(JumpTarget, jump_target, NULL, 5, 0, 0, JOF_ICINDEX) \ /* * Marks the target of the backwards jump for some loop. * * This is a jump target instruction (see `JSOp::JumpTarget`). Additionally, * it checks for interrupts and handles JIT tiering. * * The `depthHint` operand is a loop depth hint for Ion. It starts at 1 and * deeply nested loops all have the same value. * * For the convenience of the JITs, scripts must not start with this * instruction. See bug 1602390. * * Category: Control flow * Type: Jump targets * Operands: uint32_t icIndex, uint8_t depthHint * Stack: => */ \ MACRO(LoopHead, loop_head, NULL, 6, 0, 0, JOF_LOOPHEAD) \ /* * Jump to a 32-bit offset from the current bytecode. * * See "Jump instructions" above for details. * * Category: Control flow * Type: Jumps * Operands: int32_t offset * Stack: => */ \ MACRO(Goto, goto_, NULL, 5, 0, 0, JOF_JUMP) \ /* * If ToBoolean(`cond`) is false, jumps to a 32-bit offset from the current * instruction. * * Category: Control flow * Type: Jumps * Operands: int32_t forwardOffset * Stack: cond => */ \ MACRO(JumpIfFalse, jump_if_false, NULL, 5, 1, 0, JOF_JUMP|JOF_IC) \ /* * If ToBoolean(`cond`) is true, jump to a 32-bit offset from the current * instruction. * * `offset` may be positive or negative. This is the instruction used at the * end of a do-while loop to jump back to the top. * * Category: Control flow * Type: Jumps * Operands: int32_t offset * Stack: cond => */ \ MACRO(JumpIfTrue, jump_if_true, NULL, 5, 1, 0, JOF_JUMP|JOF_IC) \ /* * Short-circuit for logical AND. * * If ToBoolean(`cond`) is false, jump to a 32-bit offset from the current * instruction. The value remains on the stack. * * Category: Control flow * Type: Jumps * Operands: int32_t forwardOffset * Stack: cond => cond */ \ MACRO(And, and_, NULL, 5, 1, 1, JOF_JUMP|JOF_IC) \ /* * Short-circuit for logical OR. * * If ToBoolean(`cond`) is true, jump to a 32-bit offset from the current * instruction. The value remains on the stack. * * Category: Control flow * Type: Jumps * Operands: int32_t forwardOffset * Stack: cond => cond */ \ MACRO(Or, or_, NULL, 5, 1, 1, JOF_JUMP|JOF_IC) \ /* * Short-circuiting for nullish coalescing. * * If `val` is not null or undefined, jump to a 32-bit offset from the * current instruction. * * Category: Control flow * Type: Jumps * Operands: int32_t forwardOffset * Stack: val => val */ \ MACRO(Coalesce, coalesce, NULL, 5, 1, 1, JOF_JUMP) \ /* * Like `JSOp::JumpIfTrue`, but if the branch is taken, pop and discard an * additional stack value. * * This is used to implement `switch` statements when the * `JSOp::TableSwitch` optimization is not possible. The switch statement * * switch (expr) { * case A: stmt1; * case B: stmt2; * } * * compiles to this bytecode: * * # dispatch code - evaluate expr, check it against each `case`, * # jump to the right place in the body or to the end. * * Dup; ; StrictEq; Case L1; JumpTarget * Dup; ; StrictEq; Case L2; JumpTarget * Default LE * * # body code * L1: JumpTarget; * L2: JumpTarget; * LE: JumpTarget * * This opcode is weird: it's the only one whose ndefs varies depending on * which way a conditional branch goes. We could implement switch * statements using `JSOp::JumpIfTrue` and `JSOp::Pop`, but that would also * be awkward--putting the `JSOp::Pop` inside the `switch` body would * complicate fallthrough. * * Category: Control flow * Type: Jumps * Operands: int32_t forwardOffset * Stack: val, cond => val (if !cond) */ \ MACRO(Case, case_, NULL, 5, 2, 1, JOF_JUMP) \ /* * Like `JSOp::Goto`, but pop and discard an additional stack value. * * This appears after all cases for a non-optimized `switch` statement. If * there's a `default:` label, it jumps to that point in the body; * otherwise it jumps to the next statement. * * Category: Control flow * Type: Jumps * Operands: int32_t forwardOffset * Stack: lval => */ \ MACRO(Default, default_, NULL, 5, 1, 0, JOF_JUMP) \ /* * Optimized switch-statement dispatch, used when all `case` labels are * small integer constants. * * If `low <= i <= high`, jump to the instruction at the offset given by * `script->resumeOffsets()[firstResumeIndex + i - low]`, in bytes from the * start of the current script's bytecode. Otherwise, jump to the * instruction at `defaultOffset` from the current instruction. All of * these offsets must be in range for the current script and must point to * `JSOp::JumpTarget` instructions. * * The following inequalities must hold: `low <= high` and * `firstResumeIndex + high - low < resumeOffsets().size()`. * * Category: Control flow * Type: Jumps * Operands: int32_t defaultOffset, int32_t low, int32_t high, * uint24_t firstResumeIndex * Stack: i => */ \ MACRO(TableSwitch, table_switch, NULL, 16, 1, 0, JOF_TABLESWITCH) \ /* * Return `rval`. * * This must not be used in derived class constructors. Instead use * `JSOp::SetRval`, `JSOp::CheckReturn`, and `JSOp::RetRval`. * * Category: Control flow * Type: Return * Operands: * Stack: rval => */ \ MACRO(Return, return_, NULL, 1, 1, 0, JOF_BYTE) \ /* * Push the current stack frame's `returnValue`. If no `JSOp::SetRval` * instruction has been executed in this stack frame, this is `undefined`. * * Every stack frame has a `returnValue` slot, used by top-level scripts, * generators, async functions, and derived class constructors. Plain * functions usually use `JSOp::Return` instead. * * Category: Control flow * Type: Return * Operands: * Stack: => rval */ \ MACRO(GetRval, get_rval, NULL, 1, 0, 1, JOF_BYTE) \ /* * Store `rval` in the current stack frame's `returnValue` slot. * * This instruction must not be used in a toplevel script compiled with the * `noScriptRval` option. * * Category: Control flow * Type: Return * Operands: * Stack: rval => */ \ MACRO(SetRval, set_rval, NULL, 1, 1, 0, JOF_BYTE) \ /* * Stop execution and return the current stack frame's `returnValue`. If no * `JSOp::SetRval` instruction has been executed in this stack frame, this * is `undefined`. * * Also emitted at end of every script so consumers don't need to worry * about running off the end. * * If the current script is a derived class constructor, `returnValue` must * be an object. The script can use `JSOp::CheckReturn` to ensure this. * * Category: Control flow * Type: Return * Operands: * Stack: => */ \ MACRO(RetRval, ret_rval, NULL, 1, 0, 0, JOF_BYTE) \ /* * Check the return value in a derived class constructor. * * - If the current stack frame's `returnValue` is an object, push * `returnValue` onto the stack. * * - Otherwise, if the `returnValue` is undefined and `thisval` is an * object, push `thisval` onto the stack. * * - Otherwise, throw a TypeError. * * This is exactly what has to happen when a derived class constructor * returns. `thisval` should be the current value of `this`, or * `MagicValue(JS_UNINITIALIZED_LEXICAL)` if `this` is uninitialized. * * Implements: [The [[Construct]] internal method of JS functions][1], * steps 13 and 15. * * [1]: https://tc39.es/ecma262/#sec-ecmascript-function-objects-construct-argumentslist-newtarget * * Category: Control flow * Type: Return * Operands: * Stack: thisval => rval */ \ MACRO(CheckReturn, check_return, NULL, 1, 1, 1, JOF_BYTE) \ /* * Throw `exc`. (ノಠ益ಠ)ノ彡┴──┴ * * This sets the pending exception to `exc` and jumps to error-handling * code. If we're in a `try` block, error handling adjusts the stack and * environment chain and resumes execution at the top of the `catch` or * `finally` block. Otherwise it starts unwinding the stack. * * Implements: [*ThrowStatement* Evaluation][1], step 3. * * This is also used in for-of loops. If the body of the loop throws an * exception, we catch it, close the iterator, then use `JSOp::Throw` to * rethrow. * * [1]: https://tc39.es/ecma262/#sec-throw-statement-runtime-semantics-evaluation * * Category: Control flow * Type: Exceptions * Operands: * Stack: exc => */ \ MACRO(Throw, throw_, NULL, 1, 1, 0, JOF_BYTE) \ /* * Create and throw an Error object. * * Sometimes we know at emit time that an operation always throws. For * example, `delete super.prop;` is allowed in methods, but always throws a * ReferenceError. * * `msgNumber` determines the `.message` and [[Prototype]] of the new Error * object. It must be an error number in js/public/friend/ErrorNumbers.msg. * The number of arguments in the error message must be 0. * * Category: Control flow * Type: Exceptions * Operands: ThrowMsgKind msgNumber * Stack: => */ \ MACRO(ThrowMsg, throw_msg, NULL, 2, 0, 0, JOF_UINT8) \ /* * Throws a runtime TypeError for invalid assignment to a `const` binding. * * Category: Control flow * Type: Exceptions * Operands: uint32_t nameIndex * Stack: */ \ MACRO(ThrowSetConst, throw_set_const, NULL, 5, 0, 0, JOF_ATOM|JOF_NAME) \ /* * No-op instruction that marks the top of the bytecode for a * *TryStatement*. * * Location information for catch/finally blocks is stored in a side table, * `script->trynotes()`. * * Category: Control flow * Type: Exceptions * Operands: * Stack: => */ \ MACRO(Try, try_, NULL, 1, 0, 0, JOF_BYTE) \ /* * No-op instruction used by the exception unwinder to determine the * correct environment to unwind to when performing IteratorClose due to * destructuring. * * This instruction must appear immediately before each * `JSTRY_DESTRUCTURING` span in a script's try notes. * * Category: Control flow * Type: Exceptions * Operands: * Stack: => */ \ MACRO(TryDestructuring, try_destructuring, NULL, 1, 0, 0, JOF_BYTE) \ /* * Push and clear the pending exception. ┬──┬◡ﾉ(° -°ﾉ) * * This must be used only in the fixed sequence of instructions following a * `JSTRY_CATCH` span (see "Bytecode Invariants" above), as that's the only * way instructions would run with an exception pending. * * Used to implement catch-blocks, including the implicit ones generated as * part of for-of iteration. * * Category: Control flow * Type: Exceptions * Operands: * Stack: => exception */ \ MACRO(Exception, exception, NULL, 1, 0, 1, JOF_BYTE) \ /* * No-op instruction that marks the start of a `finally` block. * * Category: Control flow * Type: Exceptions * Operands: * Stack: => */ \ MACRO(Finally, finally, NULL, 1, 0, 0, JOF_BYTE) \ /* * Push `MagicValue(JS_UNINITIALIZED_LEXICAL)`, a magic value used to mark * a binding as uninitialized. * * This magic value must be used only by `JSOp::InitLexical`. * * Category: Variables and scopes * Type: Initialization * Operands: * Stack: => uninitialized */ \ MACRO(Uninitialized, uninitialized, NULL, 1, 0, 1, JOF_BYTE) \ /* * Initialize an optimized local lexical binding; or mark it as * uninitialized. * * This stores the value `v` in the fixed slot `localno` in the current * stack frame. If `v` is the magic value produced by `JSOp::Uninitialized`, * this marks the binding as uninitialized. Otherwise this initializes the * binding with value `v`. * * Implements: [CreateMutableBinding][1] step 3, substep "record that it is * uninitialized", and [InitializeBinding][2], for optimized locals. (Note: * this is how `const` bindings are initialized.) * * [1]: https://tc39.es/ecma262/#sec-declarative-environment-records-createmutablebinding-n-d * [2]: https://tc39.es/ecma262/#sec-declarative-environment-records-initializebinding-n-v * * Category: Variables and scopes * Type: Initialization * Operands: uint24_t localno * Stack: v => v */ \ MACRO(InitLexical, init_lexical, NULL, 4, 1, 1, JOF_LOCAL|JOF_NAME) \ /* * Initialize a global lexical binding. * * The binding must already have been created by * `GlobalOrEvalDeclInstantiation` and must be uninitialized. * * Like `JSOp::InitLexical` but for global lexicals. Unlike `InitLexical` * this can't be used to mark a binding as uninitialized. * * Category: Variables and scopes * Type: Initialization * Operands: uint32_t nameIndex * Stack: val => val */ \ MACRO(InitGLexical, init_g_lexical, NULL, 5, 1, 1, JOF_ATOM|JOF_NAME|JOF_PROPINIT|JOF_GNAME|JOF_IC) \ /* * Initialize an aliased lexical binding; or mark it as uninitialized. * * Like `JSOp::InitLexical` but for aliased bindings. * * Note: There is no even-less-optimized `InitName` instruction because JS * doesn't need it. We always know statically which binding we're * initializing. * * `hops` is usually 0, but in `function f(a=eval("var b;")) { }`, the * argument `a` is initialized from inside a nested scope, so `hops == 1`. * * Category: Variables and scopes * Type: Initialization * Operands: uint8_t hops, uint24_t slot * Stack: v => v */ \ MACRO(InitAliasedLexical, init_aliased_lexical, NULL, 5, 1, 1, JOF_ENVCOORD|JOF_NAME|JOF_PROPINIT) \ /* * Throw a ReferenceError if the value on top of the stack is uninitialized. * * Typically used after `JSOp::GetLocal` with the same `localno`. * * Implements: [GetBindingValue][1] step 3 and [SetMutableBinding][2] step * 4 for declarative Environment Records. * * [1]: https://tc39.es/ecma262/#sec-declarative-environment-records-getbindingvalue-n-s * [2]: https://tc39.es/ecma262/#sec-declarative-environment-records-setmutablebinding-n-v-s * * Category: Variables and scopes * Type: Initialization * Operands: uint24_t localno * Stack: v => v */ \ MACRO(CheckLexical, check_lexical, NULL, 4, 1, 1, JOF_LOCAL|JOF_NAME) \ /* * Like `JSOp::CheckLexical` but for aliased bindings. * * Typically used after `JSOp::GetAliasedVar` with the same hops/slot. * * Note: There are no `CheckName` or `CheckGName` instructions because * they're unnecessary. `JSOp::{Get,Set}{Name,GName}` all check for * uninitialized lexicals and throw if needed. * * Category: Variables and scopes * Type: Initialization * Operands: uint8_t hops, uint24_t slot * Stack: v => v */ \ MACRO(CheckAliasedLexical, check_aliased_lexical, NULL, 5, 1, 1, JOF_ENVCOORD|JOF_NAME) \ /* * Throw a ReferenceError if the value on top of the stack is * `MagicValue(JS_UNINITIALIZED_LEXICAL)`. Used in derived class * constructors to check `this` (which needs to be initialized before use, * by calling `super()`). * * Implements: [GetThisBinding][1] step 3. * * [1]: https://tc39.es/ecma262/#sec-function-environment-records-getthisbinding * * Category: Variables and scopes * Type: Initialization * Operands: * Stack: this => this */ \ MACRO(CheckThis, check_this, NULL, 1, 1, 1, JOF_BYTE) \ /* * Look up a name on the global lexical environment's chain and push the * environment which contains a binding for that name. If no such binding * exists, push the global lexical environment. * * Category: Variables and scopes * Type: Looking up bindings * Operands: uint32_t nameIndex * Stack: => global */ \ MACRO(BindGName, bind_g_name, NULL, 5, 0, 1, JOF_ATOM|JOF_NAME|JOF_GNAME|JOF_IC) \ /* * Look up a name on the environment chain and push the environment which * contains a binding for that name. If no such binding exists, push the * global lexical environment. * * Category: Variables and scopes * Type: Looking up bindings * Operands: uint32_t nameIndex * Stack: => env */ \ MACRO(BindName, bind_name, NULL, 5, 0, 1, JOF_ATOM|JOF_NAME|JOF_IC|JOF_USES_ENV) \ /* * Find a binding on the environment chain and push its value. * * If the binding is an uninitialized lexical, throw a ReferenceError. If * no such binding exists, throw a ReferenceError unless the next * instruction is `JSOp::Typeof`, in which case push `undefined`. * * Implements: [ResolveBinding][1] followed by [GetValue][2] * (adjusted hackily for `typeof`). * * This is the fallback `Get` instruction that handles all unoptimized * cases. Optimized instructions follow. * * [1]: https://tc39.es/ecma262/#sec-resolvebinding * [2]: https://tc39.es/ecma262/#sec-getvalue * * Category: Variables and scopes * Type: Getting binding values * Operands: uint32_t nameIndex * Stack: => val */ \ MACRO(GetName, get_name, NULL, 5, 0, 1, JOF_ATOM|JOF_NAME|JOF_IC|JOF_USES_ENV) \ /* * Find a global binding and push its value. * * This searches the global lexical environment and, failing that, the * global object. (Unlike most declarative environments, the global lexical * environment can gain more bindings after compilation, possibly shadowing * global object properties.) * * This is an optimized version of `JSOp::GetName` that skips all local * scopes, for use when the name doesn't refer to any local binding. * `NonSyntacticVariablesObject`s break this optimization, so if the * current script has a non-syntactic global scope, use `JSOp::GetName` * instead. * * Like `JSOp::GetName`, this throws a ReferenceError if no such binding is * found (unless the next instruction is `JSOp::Typeof`) or if the binding * is an uninitialized lexical. * * Category: Variables and scopes * Type: Getting binding values * Operands: uint32_t nameIndex * Stack: => val */ \ MACRO(GetGName, get_g_name, NULL, 5, 0, 1, JOF_ATOM|JOF_NAME|JOF_GNAME|JOF_IC) \ /* * Push the value of an argument that is stored in the stack frame * or in an `ArgumentsObject`. * * Category: Variables and scopes * Type: Getting binding values * Operands: uint16_t argno * Stack: => arguments[argno] */ \ MACRO(GetArg, get_arg, NULL, 3, 0, 1, JOF_QARG|JOF_NAME) \ /* * Push the value of an argument that is stored in the stack frame. Like * `JSOp::GetArg`, but ignores the frame's `ArgumentsObject` and doesn't * assert the argument is unaliased. * * Category: Variables and scopes * Type: Getting binding values * Operands: uint16_t argno * Stack: => arguments[argno] */ \ MACRO(GetFrameArg, get_frame_arg, NULL, 3, 0, 1, JOF_QARG|JOF_NAME) \ /* * Push the value of an optimized local variable. * * If the variable is an uninitialized lexical, push * `MagicValue(JS_UNINIITALIZED_LEXICAL)`. * * Category: Variables and scopes * Type: Getting binding values * Operands: uint24_t localno * Stack: => val */ \ MACRO(GetLocal, get_local, NULL, 4, 0, 1, JOF_LOCAL|JOF_NAME) \ /* * Push the number of actual arguments as Int32Value. * * This is emitted for the ArgumentsLength() intrinsic in self-hosted code. * * Category: Variables and scopes * Type: Getting binding values * Operands: * Stack: => arguments.length */ \ MACRO(ArgumentsLength, arguments_length, NULL, 1, 0, 1, JOF_BYTE) \ /* * Push the value of an argument that is stored in the stack frame. The * value on top of the stack must be an Int32Value storing the index. The * index must be less than the number of actual arguments. * * This is emitted for the GetArgument(i) intrinsic in self-hosted code. * * Category: Variables and scopes * Type: Getting binding values * Operands: * Stack: index => arguments[index] */ \ MACRO(GetActualArg, get_actual_arg, NULL, 1, 1, 1, JOF_BYTE) \ /* * Push the value of an aliased binding. * * Local bindings that aren't closed over or dynamically accessed are * stored in stack slots. Global and `with` bindings are object properties. * All other bindings are called "aliased" and stored in * `EnvironmentObject`s. * * Where possible, `Aliased` instructions are used to access aliased * bindings. (There's no difference in meaning between `AliasedVar` and * `AliasedLexical`.) Each of these instructions has operands `hops` and * `slot` that encode an [`EnvironmentCoordinate`][1], directions to the * binding from the current environment object. * * `Aliased` instructions can't be used when there's a dynamic scope (due * to non-strict `eval` or `with`) that might shadow the aliased binding. * * [1]: https://searchfox.org/mozilla-central/search?q=symbol:T_js%3A%3AEnvironmentCoordinate * * Category: Variables and scopes * Type: Getting binding values * Operands: uint8_t hops, uint24_t slot * Stack: => aliasedVar */ \ MACRO(GetAliasedVar, get_aliased_var, NULL, 5, 0, 1, JOF_ENVCOORD|JOF_NAME|JOF_USES_ENV) \ /* * Push the value of an aliased binding, which may have to bypass a DebugEnvironmentProxy * on the environment chain. * * Category: Variables and scopes * Type: Getting binding values * Operands: uint8_t hops, uint24_t slot * Stack: => aliasedVar */ \ MACRO(GetAliasedDebugVar, get_aliased_debug_var, NULL, 5, 0, 1, JOF_DEBUGCOORD|JOF_NAME) \ /* * Get the value of a module import by name and pushes it onto the stack. * * Category: Variables and scopes * Type: Getting binding values * Operands: uint32_t nameIndex * Stack: => val */ \ MACRO(GetImport, get_import, NULL, 5, 0, 1, JOF_ATOM|JOF_NAME) \ /* * Get the value of a binding from the environment `env`. If the name is * not bound in `env`, throw a ReferenceError. * * `env` must be an environment currently on the environment chain, pushed * by `JSOp::BindName` or `JSOp::BindVar`. * * Note: `JSOp::BindName` and `JSOp::GetBoundName` are the two halves of the * `JSOp::GetName` operation: finding and reading a variable. This * decomposed version is needed to implement the compound assignment and * increment/decrement operators, which get and then set a variable. The * spec says the variable lookup is done only once. If we did the lookup * twice, there would be observable bugs, thanks to dynamic scoping. We * could set the wrong variable or call proxy traps incorrectly. * * Implements: [GetValue][1] steps 4 and 6. * * [1]: https://tc39.es/ecma262/#sec-getvalue * * Category: Variables and scopes * Type: Getting binding values * Operands: uint32_t nameIndex * Stack: env => v */ \ MACRO(GetBoundName, get_bound_name, NULL, 5, 1, 1, JOF_ATOM|JOF_NAME|JOF_IC) \ /* * Push the value of an intrinsic onto the stack. * * Non-standard. Intrinsics are slots in the intrinsics holder object (see * `GlobalObject::getIntrinsicsHolder`), which is used in lieu of global * bindings in self-hosting code. * * Category: Variables and scopes * Type: Getting binding values * Operands: uint32_t nameIndex * Stack: => intrinsic[name] */ \ MACRO(GetIntrinsic, get_intrinsic, NULL, 5, 0, 1, JOF_ATOM|JOF_NAME|JOF_IC) \ /* * Pushes the currently executing function onto the stack. * * The current script must be a function script. * * Used to implement `super`. This is also used sometimes as a minor * optimization when a named function expression refers to itself by name: * * f = function fac(n) { ... fac(n - 1) ... }; * * This lets us optimize away a lexical environment that contains only the * binding for `fac`, unless it's otherwise observable (via `with`, `eval`, * or a nested closure). * * Category: Variables and scopes * Type: Getting binding values * Operands: * Stack: => callee */ \ MACRO(Callee, callee, NULL, 1, 0, 1, JOF_BYTE) \ /* * Load the callee stored in a CallObject on the environment chain. The * `numHops` operand is the number of environment objects to skip on the * environment chain. The environment chain element indicated by `numHops` * must be a CallObject. * * Category: Variables and scopes * Type: Getting binding values * Operands: uint8_t numHops * Stack: => callee */ \ MACRO(EnvCallee, env_callee, NULL, 2, 0, 1, JOF_UINT8) \ /* * Assign `val` to the binding in `env` with the name given by `nameIndex`. * Throw a ReferenceError if the binding is an uninitialized lexical. * This can call setters and/or proxy traps. * * `env` must be an environment currently on the environment chain, * pushed by `JSOp::BindName` or `JSOp::BindVar`. * * This is the fallback `Set` instruction that handles all unoptimized * cases. Optimized instructions follow. * * Implements: [PutValue][1] steps 5 and 7 for unoptimized bindings. * * Note: `JSOp::BindName` and `JSOp::SetName` are the two halves of simple * assignment: finding and setting a variable. They are two separate * instructions because, per spec, the "finding" part happens before * evaluating the right-hand side of the assignment, and the "setting" part * after. Optimized cases don't need a `Bind` instruction because the * "finding" is done statically. * * [1]: https://tc39.es/ecma262/#sec-putvalue * * Category: Variables and scopes * Type: Setting binding values * Operands: uint32_t nameIndex * Stack: env, val => val */ \ MACRO(SetName, set_name, NULL, 5, 2, 1, JOF_ATOM|JOF_NAME|JOF_PROPSET|JOF_CHECKSLOPPY|JOF_IC|JOF_USES_ENV) \ /* * Like `JSOp::SetName`, but throw a TypeError if there is no binding for * the specified name in `env`, or if the binding is immutable (a `const` * or read-only property). * * Implements: [PutValue][1] steps 5 and 7 for strict mode code. * * [1]: https://tc39.es/ecma262/#sec-putvalue * * Category: Variables and scopes * Type: Setting binding values * Operands: uint32_t nameIndex * Stack: env, val => val */ \ MACRO(StrictSetName, strict_set_name, NULL, 5, 2, 1, JOF_ATOM|JOF_NAME|JOF_PROPSET|JOF_CHECKSTRICT|JOF_IC|JOF_USES_ENV) \ /* * Like `JSOp::SetName`, but for assigning to globals. `env` must be an * environment pushed by `JSOp::BindGName`. * * Category: Variables and scopes * Type: Setting binding values * Operands: uint32_t nameIndex * Stack: env, val => val */ \ MACRO(SetGName, set_g_name, NULL, 5, 2, 1, JOF_ATOM|JOF_NAME|JOF_PROPSET|JOF_GNAME|JOF_CHECKSLOPPY|JOF_IC) \ /* * Like `JSOp::StrictSetGName`, but for assigning to globals. `env` must be * an environment pushed by `JSOp::BindGName`. * * Category: Variables and scopes * Type: Setting binding values * Operands: uint32_t nameIndex * Stack: env, val => val */ \ MACRO(StrictSetGName, strict_set_g_name, NULL, 5, 2, 1, JOF_ATOM|JOF_NAME|JOF_PROPSET|JOF_GNAME|JOF_CHECKSTRICT|JOF_IC) \ /* * Assign `val` to an argument binding that's stored in the stack frame or * in an `ArgumentsObject`. * * Category: Variables and scopes * Type: Setting binding values * Operands: uint16_t argno * Stack: val => val */ \ MACRO(SetArg, set_arg, NULL, 3, 1, 1, JOF_QARG|JOF_NAME) \ /* * Assign to an optimized local binding. * * Category: Variables and scopes * Type: Setting binding values * Operands: uint24_t localno * Stack: v => v */ \ MACRO(SetLocal, set_local, NULL, 4, 1, 1, JOF_LOCAL|JOF_NAME) \ /* * Assign to an aliased binding. * * Implements: [SetMutableBinding for declarative Environment Records][1], * in certain cases where it's known that the binding exists, is mutable, * and has been initialized. * * [1]: https://tc39.es/ecma262/#sec-declarative-environment-records-setmutablebinding-n-v-s * * Category: Variables and scopes * Type: Setting binding values * Operands: uint8_t hops, uint24_t slot * Stack: val => val */ \ MACRO(SetAliasedVar, set_aliased_var, NULL, 5, 1, 1, JOF_ENVCOORD|JOF_NAME|JOF_PROPSET|JOF_USES_ENV) \ /* * Assign to an intrinsic. * * Nonstandard. Intrinsics are used in lieu of global bindings in self- * hosted code. The value is actually stored in the intrinsics holder * object, `GlobalObject::getIntrinsicsHolder`. (Self-hosted code doesn't * have many global `var`s, but it has many `function`s.) * * Category: Variables and scopes * Type: Setting binding values * Operands: uint32_t nameIndex * Stack: val => val */ \ MACRO(SetIntrinsic, set_intrinsic, NULL, 5, 1, 1, JOF_ATOM|JOF_NAME) \ /* * Push a lexical environment onto the environment chain. * * The `LexicalScope` indicated by `lexicalScopeIndex` determines the shape * of the new `BlockLexicalEnvironmentObject`. All bindings in the new * environment are marked as uninitialized. * * Implements: [Evaluation of *Block*][1], steps 1-4. * * #### Fine print for environment chain instructions * * The following rules for `JSOp::{Push,Pop}LexicalEnv` also apply to * `JSOp::PushClassBodyEnv`, `JSOp::PushVarEnv`, and * `JSOp::{Enter,Leave}With`. * * Each `JSOp::PopLexicalEnv` instruction matches a particular * `JSOp::PushLexicalEnv` instruction in the same script and must have the * same scope and stack depth as the instruction immediately after that * `PushLexicalEnv`. * * `JSOp::PushLexicalEnv` enters a scope that extends to some set of * instructions in the script. Code must not jump into or out of this * region: control can enter only by executing `PushLexicalEnv` and can * exit only by executing a `PopLexicalEnv` or by exception unwinding. (A * `JSOp::PopLexicalEnv` is always emitted at the end of the block, and * extra copies are emitted on "exit slides", where a `break`, `continue`, * or `return` statement exits the scope.) * * The script's `JSScript::scopeNotes()` must identify exactly which * instructions begin executing in this scope. Typically this means a * single entry marking the contiguous chunk of bytecode from the * instruction after `JSOp::PushLexicalEnv` to `JSOp::PopLexicalEnv` * (inclusive); but if that range contains any instructions on exit slides, * after a `JSOp::PopLexicalEnv`, then those must be correctly noted as * *outside* the scope. * * [1]: https://tc39.es/ecma262/#sec-block-runtime-semantics-evaluation * * Category: Variables and scopes * Type: Entering and leaving environments * Operands: uint32_t lexicalScopeIndex * Stack: => */ \ MACRO(PushLexicalEnv, push_lexical_env, NULL, 5, 0, 0, JOF_SCOPE|JOF_USES_ENV) \ /* * Pop a lexical or class-body environment from the environment chain. * * See `JSOp::PushLexicalEnv` for the fine print. * * Category: Variables and scopes * Type: Entering and leaving environments * Operands: * Stack: => */ \ MACRO(PopLexicalEnv, pop_lexical_env, NULL, 1, 0, 0, JOF_BYTE|JOF_USES_ENV) \ /* * No-op instruction that indicates leaving an optimized lexical scope. * * If all bindings in a lexical scope are optimized into stack slots, then * the runtime environment objects for that scope are optimized away. No * `JSOp::{Push,Pop}LexicalEnv` instructions are emitted. However, the * debugger still needs to be notified when control exits a scope; that's * what this instruction does. * * The last instruction in a lexical or class-body scope, as indicated by * scope notes, must be either this instruction (if the scope is optimized) * or `JSOp::PopLexicalEnv` (if not). * * Category: Variables and scopes * Type: Entering and leaving environments * Operands: * Stack: => */ \ MACRO(DebugLeaveLexicalEnv, debug_leave_lexical_env, NULL, 1, 0, 0, JOF_BYTE) \ /* * Replace the current block on the environment chain with a fresh block * with uninitialized bindings. This implements the behavior of inducing a * fresh lexical environment for every iteration of a for-in/of loop whose * loop-head declares lexical variables that may be captured. * * The current environment must be a BlockLexicalEnvironmentObject. * * Category: Variables and scopes * Type: Entering and leaving environments * Operands: uint32_t lexicalScopeIndex * Stack: => */ \ MACRO(RecreateLexicalEnv, recreate_lexical_env, NULL, 5, 0, 0, JOF_SCOPE) \ /* * Like `JSOp::RecreateLexicalEnv`, but the values of all the bindings are * copied from the old block to the new one. This is used for C-style * `for(let ...; ...; ...)` loops. * * Category: Variables and scopes * Type: Entering and leaving environments * Operands: uint32_t lexicalScopeIndex * Stack: => */ \ MACRO(FreshenLexicalEnv, freshen_lexical_env, NULL, 5, 0, 0, JOF_SCOPE) \ /* * Push a ClassBody environment onto the environment chain. * * Like `JSOp::PushLexicalEnv`, but pushes a `ClassBodyEnvironmentObject` * rather than a `BlockLexicalEnvironmentObject`. `JSOp::PopLexicalEnv` is * used to pop class-body environments as well as lexical environments. * * See `JSOp::PushLexicalEnv` for the fine print. * * Category: Variables and scopes * Type: Entering and leaving environments * Operands: uint32_t lexicalScopeIndex * Stack: => */ \ MACRO(PushClassBodyEnv, push_class_body_env, NULL, 5, 0, 0, JOF_SCOPE) \ /* * Push a var environment onto the environment chain. * * Like `JSOp::PushLexicalEnv`, but pushes a `VarEnvironmentObject` rather * than a `BlockLexicalEnvironmentObject`. The difference is that * non-strict direct `eval` can add bindings to a var environment; see * `VarScope` in Scope.h. * * See `JSOp::PushLexicalEnv` for the fine print. * * There is no corresponding `JSOp::PopVarEnv` operation, because a * `VarEnvironmentObject` is never popped from the environment chain. * * Implements: Places in the spec where the VariableEnvironment is set: * * - The bit in [PerformEval][1] where, in strict direct eval, the new * eval scope is taken as *varEnv* and becomes "*runningContext*'s * VariableEnvironment". * * - The weird scoping rules for functions with default parameter * expressions, as specified in [FunctionDeclarationInstantiation][2] * step 28 ("NOTE: A separate Environment Record is needed..."). * * Note: The spec also pushes a new VariableEnvironment on entry to every * function, but the VM takes care of that as part of pushing the stack * frame, before the function script starts to run, so `JSOp::PushVarEnv` is * not needed. * * [1]: https://tc39.es/ecma262/#sec-performeval * [2]: https://tc39.es/ecma262/#sec-functiondeclarationinstantiation * * Category: Variables and scopes * Type: Entering and leaving environments * Operands: uint32_t scopeIndex * Stack: => */ \ MACRO(PushVarEnv, push_var_env, NULL, 5, 0, 0, JOF_SCOPE|JOF_USES_ENV) \ /* * Push a `WithEnvironmentObject` wrapping ToObject(`val`) to the * environment chain. * * Implements: [Evaluation of `with` statements][1], steps 2-6. * * Operations that may need to consult a WithEnvironment can't be correctly * implemented using optimized instructions like `JSOp::GetLocal`. A script * must use the deoptimized `JSOp::GetName`, `BindName`, `SetName`, and * `DelName` instead. Since those instructions don't work correctly with * optimized locals and arguments, all bindings in scopes enclosing a * `with` statement are marked as "aliased" and deoptimized too. * * See `JSOp::PushLexicalEnv` for the fine print. * * [1]: https://tc39.es/ecma262/#sec-with-statement-runtime-semantics-evaluation * * Category: Variables and scopes * Type: Entering and leaving environments * Operands: uint32_t staticWithIndex * Stack: val => */ \ MACRO(EnterWith, enter_with, NULL, 5, 1, 0, JOF_SCOPE) \ /* * Pop a `WithEnvironmentObject` from the environment chain. * * See `JSOp::PushLexicalEnv` for the fine print. * * Implements: [Evaluation of `with` statements][1], step 8. * * [1]: https://tc39.es/ecma262/#sec-with-statement-runtime-semantics-evaluation * * Category: Variables and scopes * Type: Entering and leaving environments * Operands: * Stack: => */ \ MACRO(LeaveWith, leave_with, NULL, 1, 0, 0, JOF_BYTE) \ /* * Push the current VariableEnvironment (the environment on the environment * chain designated to receive new variables). * * Implements: [Annex B.3.3.1, changes to FunctionDeclarationInstantiation * for block-level functions][1], step 1.a.ii.3.a, and similar steps in * other Annex B.3.3 algorithms, when setting the function's second binding * can't be optimized. * * [1]: https://tc39.es/ecma262/#sec-web-compat-functiondeclarationinstantiation * * Category: Variables and scopes * Type: Creating and deleting bindings * Operands: * Stack: => env */ \ MACRO(BindVar, bind_var, NULL, 1, 0, 1, JOF_BYTE|JOF_USES_ENV) \ /* * Check for conflicting bindings and then initialize them in global or * sloppy eval scripts. This is required for global scripts with any * top-level bindings, or any sloppy-eval scripts with any non-lexical * top-level bindings. * * Implements: [GlobalDeclarationInstantiation][1] and * [EvalDeclarationInstantiation][2] (except step 12). * * The `lastFun` argument is a GCThingIndex of the last hoisted top-level * function that is part of top-level script initialization. The gcthings * from index `0` thru `lastFun` contain only scopes and hoisted functions. * * [1]: https://tc39.es/ecma262/#sec-globaldeclarationinstantiation * [2]: https://tc39.es/ecma262/#sec-evaldeclarationinstantiation * * Category: Variables and scopes * Type: Creating and deleting bindings * Operands: uint32_t lastFun * Stack: => */ \ MACRO(GlobalOrEvalDeclInstantiation, global_or_eval_decl_instantiation, NULL, 5, 0, 0, JOF_GCTHING|JOF_USES_ENV) \ /* * Look up a variable on the environment chain and delete it. Push `true` * on success (if a binding was deleted, or if no such binding existed in * the first place), `false` otherwise (most kinds of bindings can't be * deleted). * * Implements: [`delete` *Identifier*][1], which [is a SyntaxError][2] in * strict mode code. * * [1]: https://tc39.es/ecma262/#sec-delete-operator-runtime-semantics-evaluation * [2]: https://tc39.es/ecma262/#sec-delete-operator-static-semantics-early-errors * * Category: Variables and scopes * Type: Creating and deleting bindings * Operands: uint32_t nameIndex * Stack: => succeeded */ \ MACRO(DelName, del_name, NULL, 5, 0, 1, JOF_ATOM|JOF_NAME|JOF_CHECKSLOPPY|JOF_USES_ENV) \ /* * Create and push the `arguments` object for the current function activation. * * When it exists, `arguments` is stored in an ordinary local variable. * `JSOp::Arguments` is used in function preludes, to populate that variable * before the function body runs, *not* each time `arguments` appears in a * function. * * If a function clearly doesn't use `arguments`, we optimize it away when * emitting bytecode. The function's script won't use `JSOp::Arguments` at * all. * * The current script must be a function script. This instruction must * execute at most once per function activation. * * Category: Variables and scopes * Type: Function environment setup * Operands: * Stack: => arguments */ \ MACRO(Arguments, arguments, NULL, 1, 0, 1, JOF_BYTE|JOF_USES_ENV) \ /* * Create and push the rest parameter array for current function call. * * This must appear only in a script for a function that has a rest * parameter. * * Category: Variables and scopes * Type: Function environment setup * Operands: * Stack: => rest */ \ MACRO(Rest, rest, NULL, 1, 0, 1, JOF_BYTE|JOF_IC) \ /* * Determines the `this` value for current function frame and pushes it * onto the stack. * * In functions, `this` is stored in a local variable. This instruction is * used in the function prologue to get the value to initialize that * variable. (This doesn't apply to arrow functions, becauses they don't * have a `this` binding; also, `this` is optimized away if it's unused.) * * Functions that have a `this` binding have a local variable named * `".this"`, which is initialized using this instruction in the function * prologue. * * In non-strict functions, `this` is always an object. Undefined/null * `this` is converted into the global `this` value. Other primitive values * are boxed. See `js::BoxNonStrictThis`. * * Category: Variables and scopes * Type: Function environment setup * Operands: * Stack: => this */ \ MACRO(FunctionThis, function_this, NULL, 1, 0, 1, JOF_BYTE) \ /* * Pop the top value from the stack and discard it. * * Category: Stack operations * Operands: * Stack: v => */ \ MACRO(Pop, pop, NULL, 1, 1, 0, JOF_BYTE) \ /* * Pop the top `n` values from the stack. `n` must be <= the current stack * depth. * * Category: Stack operations * Operands: uint16_t n * Stack: v[n-1], ..., v[1], v[0] => */ \ MACRO(PopN, pop_n, NULL, 3, -1, 0, JOF_UINT16) \ /* * Push a copy of the top value on the stack. * * Category: Stack operations * Operands: * Stack: v => v, v */ \ MACRO(Dup, dup, NULL, 1, 1, 2, JOF_BYTE) \ /* * Duplicate the top two values on the stack. * * Category: Stack operations * Operands: * Stack: v1, v2 => v1, v2, v1, v2 */ \ MACRO(Dup2, dup2, NULL, 1, 2, 4, JOF_BYTE) \ /* * Push a copy of the nth value from the top of the stack. * * `n` must be less than the current stack depth. * * Category: Stack operations * Operands: uint24_t n * Stack: v[n], v[n-1], ..., v[1], v[0] => * v[n], v[n-1], ..., v[1], v[0], v[n] */ \ MACRO(DupAt, dup_at, NULL, 4, 0, 1, JOF_UINT24) \ /* * Swap the top two values on the stack. * * Category: Stack operations * Operands: * Stack: v1, v2 => v2, v1 */ \ MACRO(Swap, swap, NULL, 1, 2, 2, JOF_BYTE) \ /* * Pick the nth element from the stack and move it to the top of the stack. * * Category: Stack operations * Operands: uint8_t n * Stack: v[n], v[n-1], ..., v[1], v[0] => v[n-1], ..., v[1], v[0], v[n] */ \ MACRO(Pick, pick, NULL, 2, 0, 0, JOF_UINT8) \ /* * Move the top of the stack value under the `n`th element of the stack. * `n` must not be 0. * * Category: Stack operations * Operands: uint8_t n * Stack: v[n], v[n-1], ..., v[1], v[0] => v[0], v[n], v[n-1], ..., v[1] */ \ MACRO(Unpick, unpick, NULL, 2, 0, 0, JOF_UINT8) \ /* * Do nothing. This is used when we need distinct bytecode locations for * various mechanisms. * * Category: Other * Operands: * Stack: => */ \ MACRO(Nop, nop, NULL, 1, 0, 0, JOF_BYTE) \ /* * No-op instruction emitted immediately after `JSOp::*Eval` so that direct * eval does not have to do slow pc-to-line mapping. * * The `lineno` operand should agree with this script's source notes about * the line number of the preceding `*Eval` instruction. * * Category: Other * Operands: uint32_t lineno * Stack: => */ \ MACRO(Lineno, lineno, NULL, 5, 0, 0, JOF_UINT32) \ /* * No-op instruction to hint that the top stack value is uninteresting. * * This affects only debug output and some error messages. * In array destructuring, we emit bytecode that is roughly equivalent to * `result.done ? undefined : result.value`. * `NopDestructuring` is emitted after the `undefined`, so that the * expression decompiler and disassembler know to casually ignore the * possibility of `undefined`, and render the result of the conditional * expression simply as "`result.value`". * * Category: Other * Operands: * Stack: => */ \ MACRO(NopDestructuring, nop_destructuring, NULL, 1, 0, 0, JOF_BYTE) \ /* * No-op instruction only emitted in some self-hosted functions. Not * handled by the JITs or Baseline Interpreter so the script always runs in * the C++ interpreter. * * Category: Other * Operands: * Stack: => */ \ MACRO(ForceInterpreter, force_interpreter, NULL, 1, 0, 0, JOF_BYTE) \ /* * Examine the top stack value, asserting that it's either a self-hosted * function or a self-hosted intrinsic. This does nothing in a non-debug * build. * * Category: Other * Operands: * Stack: checkVal => checkVal */ \ MACRO(DebugCheckSelfHosted, debug_check_self_hosted, NULL, 1, 1, 1, JOF_BYTE) \ /* * Break in the debugger, if one is attached. Otherwise this is a no-op. * * The [`Debugger` API][1] offers a way to hook into this instruction. * * Implements: [Evaluation for *DebuggerStatement*][2]. * * [1]: https://developer.mozilla.org/en-US/docs/Tools/Debugger-API/Debugger * [2]: https://tc39.es/ecma262/#sec-debugger-statement-runtime-semantics-evaluation * * Category: Other * Operands: * Stack: => */ \ MACRO(Debugger, debugger, NULL, 1, 0, 0, JOF_BYTE) // clang-format on /* * In certain circumstances it may be useful to "pad out" the opcode space to * a power of two. Use this macro to do so. */ #define FOR_EACH_TRAILING_UNUSED_OPCODE(MACRO) \ IF_RECORD_TUPLE(/* empty */, MACRO(230)) \ IF_RECORD_TUPLE(/* empty */, MACRO(231)) \ IF_RECORD_TUPLE(/* empty */, MACRO(232)) \ IF_RECORD_TUPLE(/* empty */, MACRO(233)) \ IF_RECORD_TUPLE(/* empty */, MACRO(234)) \ IF_RECORD_TUPLE(/* empty */, MACRO(235)) \ IF_RECORD_TUPLE(/* empty */, MACRO(236)) \ MACRO(237) \ MACRO(238) \ MACRO(239) \ MACRO(240) \ MACRO(241) \ MACRO(242) \ MACRO(243) \ MACRO(244) \ MACRO(245) \ MACRO(246) \ MACRO(247) \ MACRO(248) \ MACRO(249) \ MACRO(250) \ MACRO(251) \ MACRO(252) \ MACRO(253) \ MACRO(254) \ MACRO(255) namespace js { // Sanity check that opcode values and trailing unused opcodes completely cover // the [0, 256) range. Avert your eyes! You don't want to know how the // sausage gets made. // clang-format off #define PLUS_ONE(...) \ + 1 constexpr int JSOP_LIMIT = 0 FOR_EACH_OPCODE(PLUS_ONE); #undef PLUS_ONE #define TRAILING_VALUE_AND_VALUE_PLUS_ONE(val) \ val) && (val + 1 == static_assert((JSOP_LIMIT == FOR_EACH_TRAILING_UNUSED_OPCODE(TRAILING_VALUE_AND_VALUE_PLUS_ONE) 256), "trailing unused opcode values monotonically increase " "from JSOP_LIMIT to 255"); #undef TRAILING_VALUE_AND_VALUE_PLUS_ONE // clang-format on // Define JSOpLength_* constants for all ops. #define DEFINE_LENGTH_CONSTANT(op, op_snake, image, len, ...) \ constexpr size_t JSOpLength_##op = len; FOR_EACH_OPCODE(DEFINE_LENGTH_CONSTANT) #undef DEFINE_LENGTH_CONSTANT } // namespace js /* * JS operation bytecodes. */ enum class JSOp : uint8_t { #define ENUMERATE_OPCODE(op, ...) op, FOR_EACH_OPCODE(ENUMERATE_OPCODE) #undef ENUMERATE_OPCODE }; #endif // vm_Opcodes_h