mirror of
https://github.com/42wim/matterbridge.git
synced 2024-11-24 11:42:03 -08:00
847 lines
19 KiB
Go
847 lines
19 KiB
Go
package compiler
|
|
|
|
import (
|
|
"fmt"
|
|
"io"
|
|
"io/ioutil"
|
|
"path/filepath"
|
|
"reflect"
|
|
"strings"
|
|
|
|
"github.com/d5/tengo"
|
|
"github.com/d5/tengo/compiler/ast"
|
|
"github.com/d5/tengo/compiler/source"
|
|
"github.com/d5/tengo/compiler/token"
|
|
"github.com/d5/tengo/objects"
|
|
)
|
|
|
|
// Compiler compiles the AST into a bytecode.
|
|
type Compiler struct {
|
|
file *source.File
|
|
parent *Compiler
|
|
modulePath string
|
|
constants []objects.Object
|
|
symbolTable *SymbolTable
|
|
scopes []CompilationScope
|
|
scopeIndex int
|
|
modules *objects.ModuleMap
|
|
compiledModules map[string]*objects.CompiledFunction
|
|
allowFileImport bool
|
|
loops []*Loop
|
|
loopIndex int
|
|
trace io.Writer
|
|
indent int
|
|
}
|
|
|
|
// NewCompiler creates a Compiler.
|
|
func NewCompiler(file *source.File, symbolTable *SymbolTable, constants []objects.Object, modules *objects.ModuleMap, trace io.Writer) *Compiler {
|
|
mainScope := CompilationScope{
|
|
symbolInit: make(map[string]bool),
|
|
sourceMap: make(map[int]source.Pos),
|
|
}
|
|
|
|
// symbol table
|
|
if symbolTable == nil {
|
|
symbolTable = NewSymbolTable()
|
|
}
|
|
|
|
// add builtin functions to the symbol table
|
|
for idx, fn := range objects.Builtins {
|
|
symbolTable.DefineBuiltin(idx, fn.Name)
|
|
}
|
|
|
|
// builtin modules
|
|
if modules == nil {
|
|
modules = objects.NewModuleMap()
|
|
}
|
|
|
|
return &Compiler{
|
|
file: file,
|
|
symbolTable: symbolTable,
|
|
constants: constants,
|
|
scopes: []CompilationScope{mainScope},
|
|
scopeIndex: 0,
|
|
loopIndex: -1,
|
|
trace: trace,
|
|
modules: modules,
|
|
compiledModules: make(map[string]*objects.CompiledFunction),
|
|
}
|
|
}
|
|
|
|
// Compile compiles the AST node.
|
|
func (c *Compiler) Compile(node ast.Node) error {
|
|
if c.trace != nil {
|
|
if node != nil {
|
|
defer un(trace(c, fmt.Sprintf("%s (%s)", node.String(), reflect.TypeOf(node).Elem().Name())))
|
|
} else {
|
|
defer un(trace(c, "<nil>"))
|
|
}
|
|
}
|
|
|
|
switch node := node.(type) {
|
|
case *ast.File:
|
|
for _, stmt := range node.Stmts {
|
|
if err := c.Compile(stmt); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
case *ast.ExprStmt:
|
|
if err := c.Compile(node.Expr); err != nil {
|
|
return err
|
|
}
|
|
c.emit(node, OpPop)
|
|
|
|
case *ast.IncDecStmt:
|
|
op := token.AddAssign
|
|
if node.Token == token.Dec {
|
|
op = token.SubAssign
|
|
}
|
|
|
|
return c.compileAssign(node, []ast.Expr{node.Expr}, []ast.Expr{&ast.IntLit{Value: 1}}, op)
|
|
|
|
case *ast.ParenExpr:
|
|
if err := c.Compile(node.Expr); err != nil {
|
|
return err
|
|
}
|
|
|
|
case *ast.BinaryExpr:
|
|
if node.Token == token.LAnd || node.Token == token.LOr {
|
|
return c.compileLogical(node)
|
|
}
|
|
|
|
if node.Token == token.Less {
|
|
if err := c.Compile(node.RHS); err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := c.Compile(node.LHS); err != nil {
|
|
return err
|
|
}
|
|
|
|
c.emit(node, OpBinaryOp, int(token.Greater))
|
|
|
|
return nil
|
|
} else if node.Token == token.LessEq {
|
|
if err := c.Compile(node.RHS); err != nil {
|
|
return err
|
|
}
|
|
if err := c.Compile(node.LHS); err != nil {
|
|
return err
|
|
}
|
|
|
|
c.emit(node, OpBinaryOp, int(token.GreaterEq))
|
|
|
|
return nil
|
|
}
|
|
|
|
if err := c.Compile(node.LHS); err != nil {
|
|
return err
|
|
}
|
|
if err := c.Compile(node.RHS); err != nil {
|
|
return err
|
|
}
|
|
|
|
switch node.Token {
|
|
case token.Add:
|
|
c.emit(node, OpBinaryOp, int(token.Add))
|
|
case token.Sub:
|
|
c.emit(node, OpBinaryOp, int(token.Sub))
|
|
case token.Mul:
|
|
c.emit(node, OpBinaryOp, int(token.Mul))
|
|
case token.Quo:
|
|
c.emit(node, OpBinaryOp, int(token.Quo))
|
|
case token.Rem:
|
|
c.emit(node, OpBinaryOp, int(token.Rem))
|
|
case token.Greater:
|
|
c.emit(node, OpBinaryOp, int(token.Greater))
|
|
case token.GreaterEq:
|
|
c.emit(node, OpBinaryOp, int(token.GreaterEq))
|
|
case token.Equal:
|
|
c.emit(node, OpEqual)
|
|
case token.NotEqual:
|
|
c.emit(node, OpNotEqual)
|
|
case token.And:
|
|
c.emit(node, OpBinaryOp, int(token.And))
|
|
case token.Or:
|
|
c.emit(node, OpBinaryOp, int(token.Or))
|
|
case token.Xor:
|
|
c.emit(node, OpBinaryOp, int(token.Xor))
|
|
case token.AndNot:
|
|
c.emit(node, OpBinaryOp, int(token.AndNot))
|
|
case token.Shl:
|
|
c.emit(node, OpBinaryOp, int(token.Shl))
|
|
case token.Shr:
|
|
c.emit(node, OpBinaryOp, int(token.Shr))
|
|
default:
|
|
return c.errorf(node, "invalid binary operator: %s", node.Token.String())
|
|
}
|
|
|
|
case *ast.IntLit:
|
|
c.emit(node, OpConstant, c.addConstant(&objects.Int{Value: node.Value}))
|
|
|
|
case *ast.FloatLit:
|
|
c.emit(node, OpConstant, c.addConstant(&objects.Float{Value: node.Value}))
|
|
|
|
case *ast.BoolLit:
|
|
if node.Value {
|
|
c.emit(node, OpTrue)
|
|
} else {
|
|
c.emit(node, OpFalse)
|
|
}
|
|
|
|
case *ast.StringLit:
|
|
if len(node.Value) > tengo.MaxStringLen {
|
|
return c.error(node, objects.ErrStringLimit)
|
|
}
|
|
|
|
c.emit(node, OpConstant, c.addConstant(&objects.String{Value: node.Value}))
|
|
|
|
case *ast.CharLit:
|
|
c.emit(node, OpConstant, c.addConstant(&objects.Char{Value: node.Value}))
|
|
|
|
case *ast.UndefinedLit:
|
|
c.emit(node, OpNull)
|
|
|
|
case *ast.UnaryExpr:
|
|
if err := c.Compile(node.Expr); err != nil {
|
|
return err
|
|
}
|
|
|
|
switch node.Token {
|
|
case token.Not:
|
|
c.emit(node, OpLNot)
|
|
case token.Sub:
|
|
c.emit(node, OpMinus)
|
|
case token.Xor:
|
|
c.emit(node, OpBComplement)
|
|
case token.Add:
|
|
// do nothing?
|
|
default:
|
|
return c.errorf(node, "invalid unary operator: %s", node.Token.String())
|
|
}
|
|
|
|
case *ast.IfStmt:
|
|
// open new symbol table for the statement
|
|
c.symbolTable = c.symbolTable.Fork(true)
|
|
defer func() {
|
|
c.symbolTable = c.symbolTable.Parent(false)
|
|
}()
|
|
|
|
if node.Init != nil {
|
|
if err := c.Compile(node.Init); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
if err := c.Compile(node.Cond); err != nil {
|
|
return err
|
|
}
|
|
|
|
// first jump placeholder
|
|
jumpPos1 := c.emit(node, OpJumpFalsy, 0)
|
|
|
|
if err := c.Compile(node.Body); err != nil {
|
|
return err
|
|
}
|
|
|
|
if node.Else != nil {
|
|
// 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.Else); err != nil {
|
|
return err
|
|
}
|
|
|
|
// update second jump offset
|
|
curPos = len(c.currentInstructions())
|
|
c.changeOperand(jumpPos2, curPos)
|
|
} else {
|
|
// update first jump offset
|
|
curPos := len(c.currentInstructions())
|
|
c.changeOperand(jumpPos1, curPos)
|
|
}
|
|
|
|
case *ast.ForStmt:
|
|
return c.compileForStmt(node)
|
|
|
|
case *ast.ForInStmt:
|
|
return c.compileForInStmt(node)
|
|
|
|
case *ast.BranchStmt:
|
|
if node.Token == token.Break {
|
|
curLoop := c.currentLoop()
|
|
if curLoop == nil {
|
|
return c.errorf(node, "break not allowed outside loop")
|
|
}
|
|
pos := c.emit(node, OpJump, 0)
|
|
curLoop.Breaks = append(curLoop.Breaks, pos)
|
|
} else if node.Token == token.Continue {
|
|
curLoop := c.currentLoop()
|
|
if curLoop == nil {
|
|
return c.errorf(node, "continue not allowed outside loop")
|
|
}
|
|
pos := c.emit(node, OpJump, 0)
|
|
curLoop.Continues = append(curLoop.Continues, pos)
|
|
} else {
|
|
panic(fmt.Errorf("invalid branch statement: %s", node.Token.String()))
|
|
}
|
|
|
|
case *ast.BlockStmt:
|
|
if len(node.Stmts) == 0 {
|
|
return nil
|
|
}
|
|
|
|
c.symbolTable = c.symbolTable.Fork(true)
|
|
defer func() {
|
|
c.symbolTable = c.symbolTable.Parent(false)
|
|
}()
|
|
|
|
for _, stmt := range node.Stmts {
|
|
if err := c.Compile(stmt); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
case *ast.AssignStmt:
|
|
if err := c.compileAssign(node, node.LHS, node.RHS, node.Token); err != nil {
|
|
return err
|
|
}
|
|
|
|
case *ast.Ident:
|
|
symbol, _, ok := c.symbolTable.Resolve(node.Name)
|
|
if !ok {
|
|
return c.errorf(node, "unresolved reference '%s'", node.Name)
|
|
}
|
|
|
|
switch symbol.Scope {
|
|
case ScopeGlobal:
|
|
c.emit(node, OpGetGlobal, symbol.Index)
|
|
case ScopeLocal:
|
|
c.emit(node, OpGetLocal, symbol.Index)
|
|
case ScopeBuiltin:
|
|
c.emit(node, OpGetBuiltin, symbol.Index)
|
|
case ScopeFree:
|
|
c.emit(node, OpGetFree, symbol.Index)
|
|
}
|
|
|
|
case *ast.ArrayLit:
|
|
for _, elem := range node.Elements {
|
|
if err := c.Compile(elem); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
c.emit(node, OpArray, len(node.Elements))
|
|
|
|
case *ast.MapLit:
|
|
for _, elt := range node.Elements {
|
|
// key
|
|
if len(elt.Key) > tengo.MaxStringLen {
|
|
return c.error(node, objects.ErrStringLimit)
|
|
}
|
|
c.emit(node, OpConstant, c.addConstant(&objects.String{Value: elt.Key}))
|
|
|
|
// value
|
|
if err := c.Compile(elt.Value); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
c.emit(node, OpMap, len(node.Elements)*2)
|
|
|
|
case *ast.SelectorExpr: // selector on RHS side
|
|
if err := c.Compile(node.Expr); err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := c.Compile(node.Sel); err != nil {
|
|
return err
|
|
}
|
|
|
|
c.emit(node, OpIndex)
|
|
|
|
case *ast.IndexExpr:
|
|
if err := c.Compile(node.Expr); err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := c.Compile(node.Index); err != nil {
|
|
return err
|
|
}
|
|
|
|
c.emit(node, OpIndex)
|
|
|
|
case *ast.SliceExpr:
|
|
if err := c.Compile(node.Expr); err != nil {
|
|
return err
|
|
}
|
|
|
|
if node.Low != nil {
|
|
if err := c.Compile(node.Low); err != nil {
|
|
return err
|
|
}
|
|
} else {
|
|
c.emit(node, OpNull)
|
|
}
|
|
|
|
if node.High != nil {
|
|
if err := c.Compile(node.High); err != nil {
|
|
return err
|
|
}
|
|
} else {
|
|
c.emit(node, OpNull)
|
|
}
|
|
|
|
c.emit(node, OpSliceIndex)
|
|
|
|
case *ast.FuncLit:
|
|
c.enterScope()
|
|
|
|
for _, p := range node.Type.Params.List {
|
|
s := c.symbolTable.Define(p.Name)
|
|
|
|
// function arguments is not assigned directly.
|
|
s.LocalAssigned = true
|
|
}
|
|
|
|
if err := c.Compile(node.Body); err != nil {
|
|
return err
|
|
}
|
|
|
|
// code optimization
|
|
c.optimizeFunc(node)
|
|
|
|
freeSymbols := c.symbolTable.FreeSymbols()
|
|
numLocals := c.symbolTable.MaxSymbols()
|
|
instructions, sourceMap := c.leaveScope()
|
|
|
|
for _, s := range freeSymbols {
|
|
switch s.Scope {
|
|
case ScopeLocal:
|
|
if !s.LocalAssigned {
|
|
// Here, the closure is capturing a local variable that's not yet assigned its value.
|
|
// One example is a local recursive function:
|
|
//
|
|
// func() {
|
|
// foo := func(x) {
|
|
// // ..
|
|
// return foo(x-1)
|
|
// }
|
|
// }
|
|
//
|
|
// which translate into
|
|
//
|
|
// 0000 GETL 0
|
|
// 0002 CLOSURE ? 1
|
|
// 0006 DEFL 0
|
|
//
|
|
// . So the local variable (0) is being captured before it's assigned the value.
|
|
//
|
|
// Solution is to transform the code into something like this:
|
|
//
|
|
// func() {
|
|
// foo := undefined
|
|
// foo = func(x) {
|
|
// // ..
|
|
// return foo(x-1)
|
|
// }
|
|
// }
|
|
//
|
|
// that is equivalent to
|
|
//
|
|
// 0000 NULL
|
|
// 0001 DEFL 0
|
|
// 0003 GETL 0
|
|
// 0005 CLOSURE ? 1
|
|
// 0009 SETL 0
|
|
//
|
|
|
|
c.emit(node, OpNull)
|
|
c.emit(node, OpDefineLocal, s.Index)
|
|
|
|
s.LocalAssigned = true
|
|
}
|
|
|
|
c.emit(node, OpGetLocalPtr, s.Index)
|
|
case ScopeFree:
|
|
c.emit(node, OpGetFreePtr, s.Index)
|
|
}
|
|
}
|
|
|
|
compiledFunction := &objects.CompiledFunction{
|
|
Instructions: instructions,
|
|
NumLocals: numLocals,
|
|
NumParameters: len(node.Type.Params.List),
|
|
VarArgs: node.Type.Params.VarArgs,
|
|
SourceMap: sourceMap,
|
|
}
|
|
|
|
if len(freeSymbols) > 0 {
|
|
c.emit(node, OpClosure, c.addConstant(compiledFunction), len(freeSymbols))
|
|
} else {
|
|
c.emit(node, OpConstant, c.addConstant(compiledFunction))
|
|
}
|
|
|
|
case *ast.ReturnStmt:
|
|
if c.symbolTable.Parent(true) == nil {
|
|
// outside the function
|
|
return c.errorf(node, "return not allowed outside function")
|
|
}
|
|
|
|
if node.Result == nil {
|
|
c.emit(node, OpReturn, 0)
|
|
} else {
|
|
if err := c.Compile(node.Result); err != nil {
|
|
return err
|
|
}
|
|
|
|
c.emit(node, OpReturn, 1)
|
|
}
|
|
|
|
case *ast.CallExpr:
|
|
if err := c.Compile(node.Func); err != nil {
|
|
return err
|
|
}
|
|
|
|
for _, arg := range node.Args {
|
|
if err := c.Compile(arg); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
c.emit(node, OpCall, len(node.Args))
|
|
|
|
case *ast.ImportExpr:
|
|
if node.ModuleName == "" {
|
|
return c.errorf(node, "empty module name")
|
|
}
|
|
|
|
if mod := c.modules.Get(node.ModuleName); mod != nil {
|
|
v, err := mod.Import(node.ModuleName)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
switch v := v.(type) {
|
|
case []byte: // module written in Tengo
|
|
compiled, err := c.compileModule(node, node.ModuleName, node.ModuleName, v)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
c.emit(node, OpConstant, c.addConstant(compiled))
|
|
c.emit(node, OpCall, 0)
|
|
case objects.Object: // builtin module
|
|
c.emit(node, OpConstant, c.addConstant(v))
|
|
default:
|
|
panic(fmt.Errorf("invalid import value type: %T", v))
|
|
}
|
|
} else if c.allowFileImport {
|
|
moduleName := node.ModuleName
|
|
if !strings.HasSuffix(moduleName, ".tengo") {
|
|
moduleName += ".tengo"
|
|
}
|
|
|
|
modulePath, err := filepath.Abs(moduleName)
|
|
if err != nil {
|
|
return c.errorf(node, "module file path error: %s", err.Error())
|
|
}
|
|
|
|
if err := c.checkCyclicImports(node, modulePath); err != nil {
|
|
return err
|
|
}
|
|
|
|
moduleSrc, err := ioutil.ReadFile(moduleName)
|
|
if err != nil {
|
|
return c.errorf(node, "module file read error: %s", err.Error())
|
|
}
|
|
|
|
compiled, err := c.compileModule(node, moduleName, modulePath, moduleSrc)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
c.emit(node, OpConstant, c.addConstant(compiled))
|
|
c.emit(node, OpCall, 0)
|
|
} else {
|
|
return c.errorf(node, "module '%s' not found", node.ModuleName)
|
|
}
|
|
|
|
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("}")
|
|
}
|