爱特每羊队
347 lines
12 KiB
Rust
347 lines
12 KiB
Rust
//! 字节码操作码表与指令编解码。
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//!
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//! [`OpCode`] 由 `define_opcodes!` 宏从单张表生成；[`Instr`] 是 4 字节指令
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//! （opcode + rd + a + b，imm16/offset16 复用 a、b 两字节）。本模块提供
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//! 编译器发射（`encode*`）与 VM 解码（`opcode` / `rd` / `a` / `b` 等）全套函数。
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use std::fmt;
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/// Generate the `OpCode` enum plus its `TryFrom<u8>` and `Display` impls from a
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/// single table. Each row is `VARIANT = 0xXX => "DISPLAY"` — the byte value is
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/// the enum discriminant, the `TryFrom` match arm, and the `Display` name come
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/// from the same row, so the three tables can never drift. A new opcode is one
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/// row.
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///
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/// Grouping comments (`// -- Arithmetic --`) are stripped by the lexer before
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/// macro expansion, so they can be interleaved freely between rows.
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macro_rules! define_opcodes {
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( $( $name:ident = $val:literal => $disp:literal ),+ $(,)? ) => {
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/// OpCode for register-based bytecode VM.
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///
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/// Organized in groups of 16 for readability. Implemented opcodes have
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/// emitter support in the compiler; placeholder opcodes are reserved
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/// for future phases (IC, profiling, parallelization).
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#[repr(u8)]
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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#[allow(non_camel_case_types)]
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pub enum OpCode {
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$( $name = $val, )+
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}
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impl TryFrom<u8> for OpCode {
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type Error = ();
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fn try_from(value: u8) -> Result<Self, Self::Error> {
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match value {
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$( $val => Ok(OpCode::$name), )+
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_ => Err(()),
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}
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}
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}
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impl fmt::Display for OpCode {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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let name = match self {
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$( OpCode::$name => $disp, )+
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};
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write!(f, "{name}")
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}
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}
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};
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}
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define_opcodes! {
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// ── Arithmetic (0x00-0x0F) ──
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ADD = 0x00 => "ADD",
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SUB = 0x01 => "SUB",
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MUL = 0x02 => "MUL",
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DIV = 0x03 => "DIV",
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MOD = 0x04 => "MOD",
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NEG = 0x05 => "NEG",
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COMPOUND_ADD = 0x06 => "COMPOUND_ADD",
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COMPOUND_SUB = 0x07 => "COMPOUND_SUB",
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COMPOUND_MUL = 0x08 => "COMPOUND_MUL",
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COMPOUND_DIV = 0x09 => "COMPOUND_DIV",
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COMPOUND_MOD = 0x0A => "COMPOUND_MOD",
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COMPOUND_EXP = 0x0B => "COMPOUND_EXP",
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MOV = 0x0C => "MOV", // rd=dst, a=src（寄存器复制，D-07，区间拆分搬值）
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SPILL = 0x0D => "SPILL", // rd=src, ext=[slot u16]（溢出写 VM spill 栈，D-06）
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UNSPILL = 0x0E => "UNSPILL", // rd=dst, ext=[slot u16]（从 VM spill 栈恢复，D-06）
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// -- Comparison (0x10-0x1F) --
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EQ = 0x10 => "EQ",
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NEQ = 0x11 => "NEQ",
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LT = 0x12 => "LT",
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GT = 0x13 => "GT",
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LTE = 0x14 => "LTE",
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GTE = 0x15 => "GTE",
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IN = 0x16 => "IN",
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NOT = 0x17 => "NOT",
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AND = 0x18 => "AND",
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OR = 0x19 => "OR",
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STRICT_EQ = 0x1A => "STRICT_EQ",
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STRICT_NEQ = 0x1C => "STRICT_NEQ",
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UNARY_PLUS = 0x1D => "UNARY_PLUS",
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// -- Control Flow (0x20-0x2F) --
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JMP = 0x20 => "JMP",
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JMP_IF_FALSE = 0x21 => "JMP_IF_FALSE",
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JMP_IF_TRUE = 0x22 => "JMP_IF_TRUE",
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FOR_OF_INIT = 0x23 => "FOR_OF_INIT",
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FOR_OF_NEXT = 0x24 => "FOR_OF_NEXT",
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// -- Update (0x25-0x28) --
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INC_PRE = 0x25 => "INC_PRE",
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INC_POST = 0x26 => "INC_POST",
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DEC_PRE = 0x27 => "DEC_PRE",
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DEC_POST = 0x28 => "DEC_POST",
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FOR_IN_INIT = 0x29 => "FOR_IN_INIT",
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FOR_IN_NEXT = 0x2A => "FOR_IN_NEXT",
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FOR_IN_DONE = 0x2B => "FOR_IN_DONE",
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SWITCH_TABLE = 0x2C => "SWITCH_TABLE",
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FOR_IN_CLEANUP = 0x2D => "FOR_IN_CLEANUP",
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// -- Exception (0x2E-0x2F, 0x33-0x35) --
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THROW = 0x2E => "THROW",
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TRY_BEGIN = 0x2F => "TRY_BEGIN",
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TRY_END = 0x33 => "TRY_END",
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TRY_FINALLY_BEGIN = 0x34 => "TRY_FINALLY_BEGIN",
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TRY_FINALLY_END = 0x35 => "TRY_FINALLY_END",
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FOR_OF_DONE = 0x36 => "FOR_OF_DONE",
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FOR_OF_CLOSE = 0x37 => "FOR_OF_CLOSE",
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// -- Template Literal (0x38) --
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TEMPLATE_STR = 0x38 => "TEMPLATE_STR",
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// -- Small Language Features (0x39-0x3B) --
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DELETE_PROP_STATIC = 0x39 => "DELETE_PROP_STATIC",
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DELETE_PROP_DYNAMIC = 0x3A => "DELETE_PROP_DYNAMIC",
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INSTANCEOF = 0x3B => "INSTANCEOF",
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MAKE_CELL = 0x3C => "MAKE_CELL",
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CELL_GET = 0x3D => "CELL_GET",
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REST_OBJECT = 0x3E => "REST_OBJECT",
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CELL_SET = 0x3F => "CELL_SET",
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// -- Variable (0x30-0x32) --
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LOAD_VAR = 0x30 => "LOAD_VAR",
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STORE_VAR = 0x31 => "STORE_VAR",
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LOAD_CONST = 0x32 => "LOAD_CONST",
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// -- Call (0x40-0x4F) --
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CALL = 0x40 => "CALL",
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RETURN = 0x41 => "RETURN",
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CALL_NATIVE = 0x42 => "CALL_NATIVE",
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NEW_EXPRESSION = 0x43 => "NEW_EXPRESSION",
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SUPER_CALL = 0x44 => "SUPER_CALL",
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SUPER_GET_PROP = 0x45 => "SUPER_GET_PROP",
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SUPER_STATIC_GET_PROP = 0x46 => "SUPER_STATIC_GET_PROP",
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SET_HOME_OBJECT = 0x47 => "SET_HOME_OBJECT",
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DEFINE_ACCESSOR = 0x48 => "DEFINE_ACCESSOR",
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LOAD_UPVALUE = 0x49 => "LOAD_UPVALUE",
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CREATE_CLOSURE = 0x4A => "CREATE_CLOSURE",
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CREATE_REGEXP = 0x4B => "CREATE_REGEXP",
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STORE_UPVALUE = 0x4C => "STORE_UPVALUE",
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// ── Object Property (0x50-0x5F) ──
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IC_GET_PROP = 0x50 => "IC_GET_PROP",
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IC_SET_PROP = 0x51 => "IC_SET_PROP",
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GET_PROP = 0x52 => "GET_PROP",
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GET_PROP_DYNAMIC = 0x53 => "GET_PROP_DYNAMIC",
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SET_PROP = 0x54 => "SET_PROP",
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SET_PROP_DYNAMIC = 0x55 => "SET_PROP_DYNAMIC",
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NEW_OBJECT = 0x56 => "NEW_OBJECT",
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NEW_ARRAY = 0x57 => "NEW_ARRAY",
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SET_ELEM = 0x58 => "SET_ELEM",
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// -- Member Update (0x59-0x62) --
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MEMBER_INC = 0x59 => "MEMBER_INC",
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MEMBER_DEC = 0x5A => "MEMBER_DEC",
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DYN_MEMBER_INC = 0x5B => "DYN_MEMBER_INC",
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DYN_MEMBER_DEC = 0x5C => "DYN_MEMBER_DEC",
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COMPOUND_MEMBER_ADD = 0x5D => "COMPOUND_MEMBER_ADD",
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COMPOUND_MEMBER_SUB = 0x5E => "COMPOUND_MEMBER_SUB",
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COMPOUND_MEMBER_MUL = 0x5F => "COMPOUND_MEMBER_MUL",
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COMPOUND_MEMBER_DIV = 0x60 => "COMPOUND_MEMBER_DIV",
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COMPOUND_MEMBER_MOD = 0x61 => "COMPOUND_MEMBER_MOD",
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COMPOUND_MEMBER_EXP = 0x62 => "COMPOUND_MEMBER_EXP",
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// -- Profiling - placeholders (0x63-0x6F) --
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PROFILE_TYPE = 0x63 => "PROFILE_TYPE",
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PROFILE_SHAPE = 0x64 => "PROFILE_SHAPE",
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PROFILE_BRANCH = 0x65 => "PROFILE_BRANCH",
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PROFILE_CALL = 0x66 => "PROFILE_CALL",
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// ── Parallel — placeholders (0x70-0x7F) ──
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FORK = 0x70 => "FORK",
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JOIN = 0x71 => "JOIN",
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GET_PRIVATE = 0x72 => "GET_PRIVATE",
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SET_PRIVATE = 0x73 => "SET_PRIVATE",
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INIT_PRIVATE = 0x74 => "INIT_PRIVATE",
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PRIVATE_BRAND_IN = 0x75 => "PRIVATE_BRAND_IN",
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// -- Bitwise (0x80-0x8F) --
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BIT_AND = 0x80 => "BIT_AND",
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BIT_OR = 0x81 => "BIT_OR",
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BIT_XOR = 0x82 => "BIT_XOR",
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SHL = 0x83 => "SHL",
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SHR = 0x84 => "SHR",
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USHR = 0x85 => "USHR",
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BIT_NOT = 0x86 => "BIT_NOT",
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COMPOUND_AND = 0x88 => "COMPOUND_AND",
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COMPOUND_OR = 0x89 => "COMPOUND_OR",
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COMPOUND_XOR = 0x8A => "COMPOUND_XOR",
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COMPOUND_SHL = 0x8B => "COMPOUND_SHL",
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COMPOUND_SHR = 0x8C => "COMPOUND_SHR",
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COMPOUND_USHR = 0x8D => "COMPOUND_USHR",
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NULLISH = 0x8E => "NULLISH",
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JMP_IF_NULLISH = 0x8F => "JMP_IF_NULLISH",
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// ── Misc (0xF0-0xFF) ──
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NOP = 0xF0 => "NOP",
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HALT = 0xF1 => "HALT",
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TYPEOF = 0xF2 => "TYPEOF",
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VOID = 0xF3 => "VOID",
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}
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impl OpCode {
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/// 是否需要 IC 扩展字（inline cache 元数据跟随指令之后）。
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pub fn has_ic_ext_words(&self) -> bool {
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matches!(
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self,
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OpCode::IC_GET_PROP
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| OpCode::IC_SET_PROP
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| OpCode::MEMBER_INC
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| OpCode::MEMBER_DEC
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| OpCode::COMPOUND_MEMBER_ADD
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| OpCode::COMPOUND_MEMBER_SUB
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| OpCode::COMPOUND_MEMBER_MUL
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| OpCode::COMPOUND_MEMBER_DIV
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| OpCode::COMPOUND_MEMBER_MOD
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| OpCode::COMPOUND_MEMBER_EXP
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)
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}
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}
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/// 4-byte instruction.
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///
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/// Layout: `[opcode: u8] [rd: u8] [a: u8] [b: u8]`
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/// - `rd` — destination register
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/// - `a` — first source register, or imm16 low byte
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/// - `b` — second source register, or imm16 high byte
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pub type Instr = u32;
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/// 把操作码与三个操作数字节编码为一条 [`Instr`]。
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pub fn encode(op: OpCode, rd: u8, a: u8, b: u8) -> Instr {
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((b as Instr) << 24) | ((a as Instr) << 16) | ((rd as Instr) << 8) | (op as Instr)
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}
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/// 解码指令的低 8 位操作码；未知字节返回 [`OpCode::NOP`]。
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pub fn opcode(instr: Instr) -> OpCode {
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OpCode::try_from((instr & 0xFF) as u8).unwrap_or(OpCode::NOP)
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}
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/// 解码目标寄存器（bits 8-15）。
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pub fn rd(instr: Instr) -> u8 {
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((instr >> 8) & 0xFF) as u8
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}
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/// 解码第一个操作数（bits 16-23）。
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pub fn a(instr: Instr) -> u8 {
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((instr >> 16) & 0xFF) as u8
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}
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/// 解码第二个操作数（bits 24-31）。
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pub fn b(instr: Instr) -> u8 {
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((instr >> 24) & 0xFF) as u8
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}
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/// 解码 16 位立即数（bits 16-31，由 a、b 两字节拼成）。
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pub fn imm16(instr: Instr) -> u16 {
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((instr >> 16) & 0xFFFF) as u16
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}
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/// 解码 16 位有符号跳转偏移（bits 16-31）。
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pub fn offset16(instr: Instr) -> i16 {
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((instr >> 16) & 0xFFFF) as i16
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}
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/// 发射无条件跳转指令（`JMP`，偏移以 16 位补码编码）。
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pub fn encode_jmp(offset: i16) -> Instr {
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let lo = (offset as u16 & 0xFF) as u8;
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let hi = ((offset as u16 >> 8) & 0xFF) as u8;
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encode(OpCode::JMP, 0, lo, hi)
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}
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/// 发射 `JMP_IF_FALSE`：当 `rd` 寄存器为 falsy 时跳转。
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pub fn encode_jmp_if_false(rd: u8, offset: i16) -> Instr {
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let lo = (offset as u16 & 0xFF) as u8;
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let hi = ((offset as u16 >> 8) & 0xFF) as u8;
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encode(OpCode::JMP_IF_FALSE, rd, lo, hi)
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}
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/// 发射 `JMP_IF_TRUE`：当 `rd` 寄存器为 truthy 时跳转。
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pub fn encode_jmp_if_true(rd: u8, offset: i16) -> Instr {
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let lo = (offset as u16 & 0xFF) as u8;
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let hi = ((offset as u16 >> 8) & 0xFF) as u8;
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encode(OpCode::JMP_IF_TRUE, rd, lo, hi)
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}
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/// 发射 `JMP_IF_NULLISH`：当 `rd` 为 `null` / `undefined` 时跳转（`??` 短路）。
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pub fn encode_jmp_if_nullish(rd: u8, offset: i16) -> Instr {
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let lo = (offset as u16 & 0xFF) as u8;
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let hi = ((offset as u16 >> 8) & 0xFF) as u8;
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encode(OpCode::JMP_IF_NULLISH, rd, lo, hi)
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}
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/// 发射 `TRY_BEGIN`：标记 try 块开始，偏移指向 catch 处理器。
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pub fn encode_try_begin(offset: i16) -> Instr {
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let lo = (offset as u16 & 0xFF) as u8;
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let hi = ((offset as u16 >> 8) & 0xFF) as u8;
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encode(OpCode::TRY_BEGIN, 0, lo, hi)
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}
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/// 发射 `TRY_FINALLY_BEGIN`：标记 try/finally 块开始，偏移指向 finally 处理器。
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pub fn encode_try_finally_begin(offset: i16) -> Instr {
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let lo = (offset as u16 & 0xFF) as u8;
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let hi = ((offset as u16 >> 8) & 0xFF) as u8;
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encode(OpCode::TRY_FINALLY_BEGIN, 0, lo, hi)
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn opcode_table_is_byte_identical() {
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for byte in 0u8..=u8::MAX {
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if let Ok(op) = OpCode::try_from(byte) {
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assert_eq!(op as u8, byte, "discriminant mismatch for 0x{byte:02X}");
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assert!(!op.to_string().is_empty(), "empty Display for 0x{byte:02X}");
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}
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}
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assert_eq!(OpCode::ADD as u8, 0x00);
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assert_eq!(OpCode::STRICT_EQ as u8, 0x1A);
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assert_eq!(OpCode::JMP_IF_NULLISH as u8, 0x8F);
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assert_eq!(OpCode::VOID as u8, 0xF3);
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assert_eq!(OpCode::MOV as u8, 0x0C);
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assert_eq!(OpCode::SPILL as u8, 0x0D);
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assert_eq!(OpCode::UNSPILL as u8, 0x0E);
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assert_eq!(OpCode::ADD.to_string(), "ADD");
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assert_eq!(OpCode::COMPOUND_MEMBER_EXP.to_string(), "COMPOUND_MEMBER_EXP");
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assert_eq!(OpCode::MOV.to_string(), "MOV");
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assert_eq!(OpCode::SPILL.to_string(), "SPILL");
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assert_eq!(OpCode::UNSPILL.to_string(), "UNSPILL");
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assert!(OpCode::try_from(0x1B).is_err());
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assert!(OpCode::try_from(0xFF).is_err());
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let ic_count = (0u8..=u8::MAX)
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.filter_map(|b| OpCode::try_from(b).ok())
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.filter(OpCode::has_ic_ext_words)
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.count();
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assert_eq!(ic_count, 10);
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}
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}
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