mirror of
https://github.com/cwinfo/matterbridge.git
synced 2024-11-23 08:11:36 +00:00
847 lines
19 KiB
Go
847 lines
19 KiB
Go
package compiler
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import (
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"fmt"
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"io"
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"io/ioutil"
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"path/filepath"
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"reflect"
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"strings"
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"github.com/d5/tengo"
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"github.com/d5/tengo/compiler/ast"
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"github.com/d5/tengo/compiler/source"
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"github.com/d5/tengo/compiler/token"
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"github.com/d5/tengo/objects"
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)
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// Compiler compiles the AST into a bytecode.
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type Compiler struct {
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file *source.File
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parent *Compiler
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modulePath string
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constants []objects.Object
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symbolTable *SymbolTable
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scopes []CompilationScope
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scopeIndex int
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modules *objects.ModuleMap
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compiledModules map[string]*objects.CompiledFunction
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allowFileImport bool
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loops []*Loop
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loopIndex int
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trace io.Writer
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indent int
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}
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// NewCompiler creates a Compiler.
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func NewCompiler(file *source.File, symbolTable *SymbolTable, constants []objects.Object, modules *objects.ModuleMap, trace io.Writer) *Compiler {
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mainScope := CompilationScope{
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symbolInit: make(map[string]bool),
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sourceMap: make(map[int]source.Pos),
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}
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// symbol table
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if symbolTable == nil {
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symbolTable = NewSymbolTable()
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}
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// add builtin functions to the symbol table
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for idx, fn := range objects.Builtins {
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symbolTable.DefineBuiltin(idx, fn.Name)
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}
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// builtin modules
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if modules == nil {
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modules = objects.NewModuleMap()
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}
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return &Compiler{
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file: file,
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symbolTable: symbolTable,
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constants: constants,
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scopes: []CompilationScope{mainScope},
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scopeIndex: 0,
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loopIndex: -1,
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trace: trace,
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modules: modules,
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compiledModules: make(map[string]*objects.CompiledFunction),
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}
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}
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// Compile compiles the AST node.
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func (c *Compiler) Compile(node ast.Node) error {
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if c.trace != nil {
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if node != nil {
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defer un(trace(c, fmt.Sprintf("%s (%s)", node.String(), reflect.TypeOf(node).Elem().Name())))
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} else {
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defer un(trace(c, "<nil>"))
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}
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}
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switch node := node.(type) {
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case *ast.File:
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for _, stmt := range node.Stmts {
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if err := c.Compile(stmt); err != nil {
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return err
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}
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}
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case *ast.ExprStmt:
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if err := c.Compile(node.Expr); err != nil {
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return err
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}
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c.emit(node, OpPop)
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case *ast.IncDecStmt:
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op := token.AddAssign
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if node.Token == token.Dec {
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op = token.SubAssign
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}
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return c.compileAssign(node, []ast.Expr{node.Expr}, []ast.Expr{&ast.IntLit{Value: 1}}, op)
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case *ast.ParenExpr:
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if err := c.Compile(node.Expr); err != nil {
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return err
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}
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case *ast.BinaryExpr:
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if node.Token == token.LAnd || node.Token == token.LOr {
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return c.compileLogical(node)
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}
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if node.Token == token.Less {
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if err := c.Compile(node.RHS); err != nil {
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return err
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}
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if err := c.Compile(node.LHS); err != nil {
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return err
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}
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c.emit(node, OpBinaryOp, int(token.Greater))
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return nil
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} else if node.Token == token.LessEq {
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if err := c.Compile(node.RHS); err != nil {
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return err
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}
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if err := c.Compile(node.LHS); err != nil {
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return err
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}
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c.emit(node, OpBinaryOp, int(token.GreaterEq))
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return nil
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}
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if err := c.Compile(node.LHS); err != nil {
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return err
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}
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if err := c.Compile(node.RHS); err != nil {
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return err
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}
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switch node.Token {
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case token.Add:
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c.emit(node, OpBinaryOp, int(token.Add))
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case token.Sub:
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c.emit(node, OpBinaryOp, int(token.Sub))
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case token.Mul:
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c.emit(node, OpBinaryOp, int(token.Mul))
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case token.Quo:
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c.emit(node, OpBinaryOp, int(token.Quo))
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case token.Rem:
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c.emit(node, OpBinaryOp, int(token.Rem))
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case token.Greater:
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c.emit(node, OpBinaryOp, int(token.Greater))
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case token.GreaterEq:
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c.emit(node, OpBinaryOp, int(token.GreaterEq))
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case token.Equal:
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c.emit(node, OpEqual)
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case token.NotEqual:
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c.emit(node, OpNotEqual)
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case token.And:
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c.emit(node, OpBinaryOp, int(token.And))
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case token.Or:
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c.emit(node, OpBinaryOp, int(token.Or))
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case token.Xor:
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c.emit(node, OpBinaryOp, int(token.Xor))
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case token.AndNot:
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c.emit(node, OpBinaryOp, int(token.AndNot))
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case token.Shl:
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c.emit(node, OpBinaryOp, int(token.Shl))
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case token.Shr:
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c.emit(node, OpBinaryOp, int(token.Shr))
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default:
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return c.errorf(node, "invalid binary operator: %s", node.Token.String())
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}
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case *ast.IntLit:
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c.emit(node, OpConstant, c.addConstant(&objects.Int{Value: node.Value}))
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case *ast.FloatLit:
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c.emit(node, OpConstant, c.addConstant(&objects.Float{Value: node.Value}))
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case *ast.BoolLit:
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if node.Value {
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c.emit(node, OpTrue)
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} else {
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c.emit(node, OpFalse)
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}
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case *ast.StringLit:
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if len(node.Value) > tengo.MaxStringLen {
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return c.error(node, objects.ErrStringLimit)
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}
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c.emit(node, OpConstant, c.addConstant(&objects.String{Value: node.Value}))
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case *ast.CharLit:
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c.emit(node, OpConstant, c.addConstant(&objects.Char{Value: node.Value}))
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case *ast.UndefinedLit:
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c.emit(node, OpNull)
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case *ast.UnaryExpr:
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if err := c.Compile(node.Expr); err != nil {
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return err
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}
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switch node.Token {
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case token.Not:
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c.emit(node, OpLNot)
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case token.Sub:
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c.emit(node, OpMinus)
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case token.Xor:
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c.emit(node, OpBComplement)
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case token.Add:
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// do nothing?
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default:
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return c.errorf(node, "invalid unary operator: %s", node.Token.String())
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}
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case *ast.IfStmt:
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// open new symbol table for the statement
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c.symbolTable = c.symbolTable.Fork(true)
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defer func() {
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c.symbolTable = c.symbolTable.Parent(false)
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}()
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if node.Init != nil {
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if err := c.Compile(node.Init); err != nil {
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return err
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}
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}
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if err := c.Compile(node.Cond); err != nil {
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return err
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}
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// first jump placeholder
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jumpPos1 := c.emit(node, OpJumpFalsy, 0)
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if err := c.Compile(node.Body); err != nil {
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return err
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}
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if node.Else != nil {
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// second jump placeholder
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jumpPos2 := c.emit(node, OpJump, 0)
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// update first jump offset
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curPos := len(c.currentInstructions())
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c.changeOperand(jumpPos1, curPos)
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if err := c.Compile(node.Else); err != nil {
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return err
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}
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// update second jump offset
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curPos = len(c.currentInstructions())
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c.changeOperand(jumpPos2, curPos)
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} else {
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// update first jump offset
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curPos := len(c.currentInstructions())
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c.changeOperand(jumpPos1, curPos)
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}
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case *ast.ForStmt:
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return c.compileForStmt(node)
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case *ast.ForInStmt:
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return c.compileForInStmt(node)
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case *ast.BranchStmt:
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if node.Token == token.Break {
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curLoop := c.currentLoop()
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if curLoop == nil {
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return c.errorf(node, "break not allowed outside loop")
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}
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pos := c.emit(node, OpJump, 0)
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curLoop.Breaks = append(curLoop.Breaks, pos)
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} else if node.Token == token.Continue {
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curLoop := c.currentLoop()
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if curLoop == nil {
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return c.errorf(node, "continue not allowed outside loop")
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}
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pos := c.emit(node, OpJump, 0)
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curLoop.Continues = append(curLoop.Continues, pos)
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} else {
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panic(fmt.Errorf("invalid branch statement: %s", node.Token.String()))
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}
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case *ast.BlockStmt:
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if len(node.Stmts) == 0 {
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return nil
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}
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c.symbolTable = c.symbolTable.Fork(true)
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defer func() {
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c.symbolTable = c.symbolTable.Parent(false)
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}()
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for _, stmt := range node.Stmts {
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if err := c.Compile(stmt); err != nil {
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return err
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}
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}
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case *ast.AssignStmt:
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if err := c.compileAssign(node, node.LHS, node.RHS, node.Token); err != nil {
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return err
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}
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case *ast.Ident:
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symbol, _, ok := c.symbolTable.Resolve(node.Name)
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if !ok {
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return c.errorf(node, "unresolved reference '%s'", node.Name)
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}
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switch symbol.Scope {
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case ScopeGlobal:
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c.emit(node, OpGetGlobal, symbol.Index)
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case ScopeLocal:
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c.emit(node, OpGetLocal, symbol.Index)
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case ScopeBuiltin:
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c.emit(node, OpGetBuiltin, symbol.Index)
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case ScopeFree:
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c.emit(node, OpGetFree, symbol.Index)
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}
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case *ast.ArrayLit:
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for _, elem := range node.Elements {
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if err := c.Compile(elem); err != nil {
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return err
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}
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}
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c.emit(node, OpArray, len(node.Elements))
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case *ast.MapLit:
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for _, elt := range node.Elements {
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// key
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if len(elt.Key) > tengo.MaxStringLen {
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return c.error(node, objects.ErrStringLimit)
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}
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c.emit(node, OpConstant, c.addConstant(&objects.String{Value: elt.Key}))
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// value
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if err := c.Compile(elt.Value); err != nil {
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return err
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}
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}
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c.emit(node, OpMap, len(node.Elements)*2)
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case *ast.SelectorExpr: // selector on RHS side
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if err := c.Compile(node.Expr); err != nil {
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return err
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}
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if err := c.Compile(node.Sel); err != nil {
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return err
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}
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c.emit(node, OpIndex)
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case *ast.IndexExpr:
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if err := c.Compile(node.Expr); err != nil {
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return err
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}
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if err := c.Compile(node.Index); err != nil {
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return err
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}
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c.emit(node, OpIndex)
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case *ast.SliceExpr:
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if err := c.Compile(node.Expr); err != nil {
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return err
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}
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if node.Low != nil {
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if err := c.Compile(node.Low); err != nil {
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return err
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}
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} else {
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c.emit(node, OpNull)
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}
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if node.High != nil {
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if err := c.Compile(node.High); err != nil {
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return err
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}
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} else {
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c.emit(node, OpNull)
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}
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c.emit(node, OpSliceIndex)
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case *ast.FuncLit:
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c.enterScope()
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for _, p := range node.Type.Params.List {
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s := c.symbolTable.Define(p.Name)
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// function arguments is not assigned directly.
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s.LocalAssigned = true
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}
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if err := c.Compile(node.Body); err != nil {
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return err
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}
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// code optimization
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c.optimizeFunc(node)
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freeSymbols := c.symbolTable.FreeSymbols()
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numLocals := c.symbolTable.MaxSymbols()
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instructions, sourceMap := c.leaveScope()
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for _, s := range freeSymbols {
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switch s.Scope {
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case ScopeLocal:
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if !s.LocalAssigned {
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// Here, the closure is capturing a local variable that's not yet assigned its value.
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// One example is a local recursive function:
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//
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// func() {
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// foo := func(x) {
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// // ..
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// return foo(x-1)
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// }
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// }
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//
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// which translate into
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//
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// 0000 GETL 0
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// 0002 CLOSURE ? 1
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// 0006 DEFL 0
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//
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// . So the local variable (0) is being captured before it's assigned the value.
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//
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// Solution is to transform the code into something like this:
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//
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// func() {
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// foo := undefined
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// foo = func(x) {
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// // ..
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// return foo(x-1)
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// }
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// }
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//
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// that is equivalent to
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//
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// 0000 NULL
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// 0001 DEFL 0
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// 0003 GETL 0
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// 0005 CLOSURE ? 1
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// 0009 SETL 0
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//
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c.emit(node, OpNull)
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c.emit(node, OpDefineLocal, s.Index)
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s.LocalAssigned = true
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}
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c.emit(node, OpGetLocalPtr, s.Index)
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case ScopeFree:
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c.emit(node, OpGetFreePtr, s.Index)
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}
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}
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compiledFunction := &objects.CompiledFunction{
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Instructions: instructions,
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NumLocals: numLocals,
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NumParameters: len(node.Type.Params.List),
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VarArgs: node.Type.Params.VarArgs,
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SourceMap: sourceMap,
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}
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if len(freeSymbols) > 0 {
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c.emit(node, OpClosure, c.addConstant(compiledFunction), len(freeSymbols))
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} else {
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c.emit(node, OpConstant, c.addConstant(compiledFunction))
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}
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case *ast.ReturnStmt:
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if c.symbolTable.Parent(true) == nil {
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// outside the function
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return c.errorf(node, "return not allowed outside function")
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}
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if node.Result == nil {
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c.emit(node, OpReturn, 0)
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} else {
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if err := c.Compile(node.Result); err != nil {
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return err
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}
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c.emit(node, OpReturn, 1)
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}
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case *ast.CallExpr:
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if err := c.Compile(node.Func); err != nil {
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return err
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}
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for _, arg := range node.Args {
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if err := c.Compile(arg); err != nil {
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return err
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}
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}
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c.emit(node, OpCall, len(node.Args))
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case *ast.ImportExpr:
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if node.ModuleName == "" {
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return c.errorf(node, "empty module name")
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}
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if mod := c.modules.Get(node.ModuleName); mod != nil {
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v, err := mod.Import(node.ModuleName)
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if err != nil {
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return err
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}
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switch v := v.(type) {
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case []byte: // module written in Tengo
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compiled, err := c.compileModule(node, node.ModuleName, node.ModuleName, v)
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if err != nil {
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return err
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}
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c.emit(node, OpConstant, c.addConstant(compiled))
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c.emit(node, OpCall, 0)
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case objects.Object: // builtin module
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c.emit(node, OpConstant, c.addConstant(v))
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default:
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panic(fmt.Errorf("invalid import value type: %T", v))
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}
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} else if c.allowFileImport {
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moduleName := node.ModuleName
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if !strings.HasSuffix(moduleName, ".tengo") {
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moduleName += ".tengo"
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}
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modulePath, err := filepath.Abs(moduleName)
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if err != nil {
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return c.errorf(node, "module file path error: %s", err.Error())
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}
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if err := c.checkCyclicImports(node, modulePath); err != nil {
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return err
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}
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moduleSrc, err := ioutil.ReadFile(moduleName)
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if err != nil {
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return c.errorf(node, "module file read error: %s", err.Error())
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}
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compiled, err := c.compileModule(node, moduleName, modulePath, moduleSrc)
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if err != nil {
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return err
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}
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c.emit(node, OpConstant, c.addConstant(compiled))
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c.emit(node, OpCall, 0)
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} else {
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return c.errorf(node, "module '%s' not found", node.ModuleName)
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}
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|
|
case *ast.ExportStmt:
|
|
// export statement must be in top-level scope
|
|
if c.scopeIndex != 0 {
|
|
return c.errorf(node, "export not allowed inside function")
|
|
}
|
|
|
|
// export statement is simply ignore when compiling non-module code
|
|
if c.parent == nil {
|
|
break
|
|
}
|
|
|
|
if err := c.Compile(node.Result); err != nil {
|
|
return err
|
|
}
|
|
|
|
c.emit(node, OpImmutable)
|
|
c.emit(node, OpReturn, 1)
|
|
|
|
case *ast.ErrorExpr:
|
|
if err := c.Compile(node.Expr); err != nil {
|
|
return err
|
|
}
|
|
|
|
c.emit(node, OpError)
|
|
|
|
case *ast.ImmutableExpr:
|
|
if err := c.Compile(node.Expr); err != nil {
|
|
return err
|
|
}
|
|
|
|
c.emit(node, OpImmutable)
|
|
|
|
case *ast.CondExpr:
|
|
if err := c.Compile(node.Cond); err != nil {
|
|
return err
|
|
}
|
|
|
|
// first jump placeholder
|
|
jumpPos1 := c.emit(node, OpJumpFalsy, 0)
|
|
|
|
if err := c.Compile(node.True); err != nil {
|
|
return err
|
|
}
|
|
|
|
// second jump placeholder
|
|
jumpPos2 := c.emit(node, OpJump, 0)
|
|
|
|
// update first jump offset
|
|
curPos := len(c.currentInstructions())
|
|
c.changeOperand(jumpPos1, curPos)
|
|
|
|
if err := c.Compile(node.False); err != nil {
|
|
return err
|
|
}
|
|
|
|
// update second jump offset
|
|
curPos = len(c.currentInstructions())
|
|
c.changeOperand(jumpPos2, curPos)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// Bytecode returns a compiled bytecode.
|
|
func (c *Compiler) Bytecode() *Bytecode {
|
|
return &Bytecode{
|
|
FileSet: c.file.Set(),
|
|
MainFunction: &objects.CompiledFunction{
|
|
Instructions: c.currentInstructions(),
|
|
SourceMap: c.currentSourceMap(),
|
|
},
|
|
Constants: c.constants,
|
|
}
|
|
}
|
|
|
|
// EnableFileImport enables or disables module loading from local files.
|
|
// Local file modules are disabled by default.
|
|
func (c *Compiler) EnableFileImport(enable bool) {
|
|
c.allowFileImport = enable
|
|
}
|
|
|
|
func (c *Compiler) fork(file *source.File, modulePath string, symbolTable *SymbolTable) *Compiler {
|
|
child := NewCompiler(file, symbolTable, nil, c.modules, c.trace)
|
|
child.modulePath = modulePath // module file path
|
|
child.parent = c // parent to set to current compiler
|
|
|
|
return child
|
|
}
|
|
|
|
func (c *Compiler) error(node ast.Node, err error) error {
|
|
return &Error{
|
|
fileSet: c.file.Set(),
|
|
node: node,
|
|
error: err,
|
|
}
|
|
}
|
|
|
|
func (c *Compiler) errorf(node ast.Node, format string, args ...interface{}) error {
|
|
return &Error{
|
|
fileSet: c.file.Set(),
|
|
node: node,
|
|
error: fmt.Errorf(format, args...),
|
|
}
|
|
}
|
|
|
|
func (c *Compiler) addConstant(o objects.Object) int {
|
|
if c.parent != nil {
|
|
// module compilers will use their parent's constants array
|
|
return c.parent.addConstant(o)
|
|
}
|
|
|
|
c.constants = append(c.constants, o)
|
|
|
|
if c.trace != nil {
|
|
c.printTrace(fmt.Sprintf("CONST %04d %s", len(c.constants)-1, o))
|
|
}
|
|
|
|
return len(c.constants) - 1
|
|
}
|
|
|
|
func (c *Compiler) addInstruction(b []byte) int {
|
|
posNewIns := len(c.currentInstructions())
|
|
|
|
c.scopes[c.scopeIndex].instructions = append(c.currentInstructions(), b...)
|
|
|
|
return posNewIns
|
|
}
|
|
|
|
func (c *Compiler) replaceInstruction(pos int, inst []byte) {
|
|
copy(c.currentInstructions()[pos:], inst)
|
|
|
|
if c.trace != nil {
|
|
c.printTrace(fmt.Sprintf("REPLC %s",
|
|
FormatInstructions(c.scopes[c.scopeIndex].instructions[pos:], pos)[0]))
|
|
}
|
|
}
|
|
|
|
func (c *Compiler) changeOperand(opPos int, operand ...int) {
|
|
op := Opcode(c.currentInstructions()[opPos])
|
|
inst := MakeInstruction(op, operand...)
|
|
|
|
c.replaceInstruction(opPos, inst)
|
|
}
|
|
|
|
// optimizeFunc performs some code-level optimization for the current function instructions
|
|
// it removes unreachable (dead code) instructions and adds "returns" instruction if needed.
|
|
func (c *Compiler) optimizeFunc(node ast.Node) {
|
|
// any instructions between RETURN and the function end
|
|
// or instructions between RETURN and jump target position
|
|
// are considered as unreachable.
|
|
|
|
// pass 1. identify all jump destinations
|
|
dsts := make(map[int]bool)
|
|
iterateInstructions(c.scopes[c.scopeIndex].instructions, func(pos int, opcode Opcode, operands []int) bool {
|
|
switch opcode {
|
|
case OpJump, OpJumpFalsy, OpAndJump, OpOrJump:
|
|
dsts[operands[0]] = true
|
|
}
|
|
|
|
return true
|
|
})
|
|
|
|
var newInsts []byte
|
|
|
|
// pass 2. eliminate dead code
|
|
posMap := make(map[int]int) // old position to new position
|
|
var dstIdx int
|
|
var deadCode bool
|
|
iterateInstructions(c.scopes[c.scopeIndex].instructions, func(pos int, opcode Opcode, operands []int) bool {
|
|
switch {
|
|
case opcode == OpReturn:
|
|
if deadCode {
|
|
return true
|
|
}
|
|
deadCode = true
|
|
case dsts[pos]:
|
|
dstIdx++
|
|
deadCode = false
|
|
case deadCode:
|
|
return true
|
|
}
|
|
|
|
posMap[pos] = len(newInsts)
|
|
newInsts = append(newInsts, MakeInstruction(opcode, operands...)...)
|
|
return true
|
|
})
|
|
|
|
// pass 3. update jump positions
|
|
var lastOp Opcode
|
|
var appendReturn bool
|
|
endPos := len(c.scopes[c.scopeIndex].instructions)
|
|
iterateInstructions(newInsts, func(pos int, opcode Opcode, operands []int) bool {
|
|
switch opcode {
|
|
case OpJump, OpJumpFalsy, OpAndJump, OpOrJump:
|
|
newDst, ok := posMap[operands[0]]
|
|
if ok {
|
|
copy(newInsts[pos:], MakeInstruction(opcode, newDst))
|
|
} else if endPos == operands[0] {
|
|
// there's a jump instruction that jumps to the end of function
|
|
// compiler should append "return".
|
|
appendReturn = true
|
|
} else {
|
|
panic(fmt.Errorf("invalid jump position: %d", newDst))
|
|
}
|
|
}
|
|
lastOp = opcode
|
|
return true
|
|
})
|
|
if lastOp != OpReturn {
|
|
appendReturn = true
|
|
}
|
|
|
|
// pass 4. update source map
|
|
newSourceMap := make(map[int]source.Pos)
|
|
for pos, srcPos := range c.scopes[c.scopeIndex].sourceMap {
|
|
newPos, ok := posMap[pos]
|
|
if ok {
|
|
newSourceMap[newPos] = srcPos
|
|
}
|
|
}
|
|
|
|
c.scopes[c.scopeIndex].instructions = newInsts
|
|
c.scopes[c.scopeIndex].sourceMap = newSourceMap
|
|
|
|
// append "return"
|
|
if appendReturn {
|
|
c.emit(node, OpReturn, 0)
|
|
}
|
|
}
|
|
|
|
func (c *Compiler) emit(node ast.Node, opcode Opcode, operands ...int) int {
|
|
filePos := source.NoPos
|
|
if node != nil {
|
|
filePos = node.Pos()
|
|
}
|
|
|
|
inst := MakeInstruction(opcode, operands...)
|
|
pos := c.addInstruction(inst)
|
|
c.scopes[c.scopeIndex].sourceMap[pos] = filePos
|
|
|
|
if c.trace != nil {
|
|
c.printTrace(fmt.Sprintf("EMIT %s",
|
|
FormatInstructions(c.scopes[c.scopeIndex].instructions[pos:], pos)[0]))
|
|
}
|
|
|
|
return pos
|
|
}
|
|
|
|
func (c *Compiler) printTrace(a ...interface{}) {
|
|
const (
|
|
dots = ". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . "
|
|
n = len(dots)
|
|
)
|
|
|
|
i := 2 * c.indent
|
|
for i > n {
|
|
_, _ = fmt.Fprint(c.trace, dots)
|
|
i -= n
|
|
}
|
|
_, _ = fmt.Fprint(c.trace, dots[0:i])
|
|
_, _ = fmt.Fprintln(c.trace, a...)
|
|
}
|
|
|
|
func trace(c *Compiler, msg string) *Compiler {
|
|
c.printTrace(msg, "{")
|
|
c.indent++
|
|
|
|
return c
|
|
}
|
|
|
|
func un(c *Compiler) {
|
|
c.indent--
|
|
c.printTrace("}")
|
|
}
|