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Added constant folding to variable assignments. Avoid using reference…
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…s where possible.

(cherry picked from commit b09a6bf)
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@dop251 @Gabri3l
dop251 authored and Gabri3l committed Sep 1, 2022
1 parent 33b5ee8 commit 551e150
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Showing 6 changed files with 255 additions and 89 deletions.
13 changes: 8 additions & 5 deletions compiler.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -395,17 +395,21 @@ func (p *Program) addSrcMap(srcPos int) {
func (s *scope) lookupName(name unistring.String) (binding *binding, noDynamics bool) {
noDynamics = true
toStash := false
for curScope := s; curScope != nil; curScope = curScope.outer {
if curScope.dynamic {
noDynamics = false
} else {
for curScope := s; ; curScope = curScope.outer {
if curScope.outer != nil {
if b, exists := curScope.boundNames[name]; exists {
if toStash && !b.inStash {
b.moveToStash()
}
binding = b
return
}
} else {
noDynamics = false
return
}
if curScope.dynamic {
noDynamics = false
}
if name == "arguments" && curScope.function && !curScope.arrow {
curScope.argsNeeded = true
Expand All @@ -416,7 +420,6 @@ func (s *scope) lookupName(name unistring.String) (binding *binding, noDynamics
toStash = true
}
}
return
}

func (s *scope) ensureBoundNamesCreated() {
Expand Down
71 changes: 32 additions & 39 deletions compiler_expr.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -395,11 +395,11 @@ func (e *compiledIdentifierExpr) emitGetterAndCallee() {
func (e *compiledIdentifierExpr) emitVarSetter1(putOnStack bool, emitRight func(isRef bool)) {
e.addSrcMap()
c := e.c
if c.scope.strict {
c.checkIdentifierLName(e.name, e.offset)
}

if b, noDynamics := c.scope.lookupName(e.name); noDynamics {
if c.scope.strict {
c.checkIdentifierLName(e.name, e.offset)
}
emitRight(false)
if b != nil {
if putOnStack {
Expand All @@ -418,15 +418,7 @@ func (e *compiledIdentifierExpr) emitVarSetter1(putOnStack bool, emitRight func(
}
}
} else {
if b != nil {
b.emitResolveVar(c.scope.strict)
} else {
if c.scope.strict {
c.emit(resolveVar1Strict(e.name))
} else {
c.emit(resolveVar1(e.name))
}
}
c.emitVarRef(e.name, e.offset, b)
emitRight(true)
if putOnStack {
c.emit(putValue)
Expand All @@ -438,16 +430,15 @@ func (e *compiledIdentifierExpr) emitVarSetter1(putOnStack bool, emitRight func(

func (e *compiledIdentifierExpr) emitVarSetter(valueExpr compiledExpr, putOnStack bool) {
e.emitVarSetter1(putOnStack, func(bool) {
e.c.emitExpr(valueExpr, true)
e.c.emitNamedOrConst(valueExpr, e.name)
})
}

func (c *compiler) emitVarRef(name unistring.String, offset int) {
func (c *compiler) emitVarRef(name unistring.String, offset int, b *binding) {
if c.scope.strict {
c.checkIdentifierLName(name, offset)
}

b, _ := c.scope.lookupName(name)
if b != nil {
b.emitResolveVar(c.scope.strict)
} else {
Expand All @@ -460,7 +451,8 @@ func (c *compiler) emitVarRef(name unistring.String, offset int) {
}

func (e *compiledIdentifierExpr) emitRef() {
e.c.emitVarRef(e.name, e.offset)
b, _ := e.c.scope.lookupName(e.name)
e.c.emitVarRef(e.name, e.offset, b)
}

func (e *compiledIdentifierExpr) emitSetter(valueExpr compiledExpr, putOnStack bool) {
Expand Down Expand Up @@ -773,13 +765,6 @@ func (e *deleteGlobalExpr) emitGetter(putOnStack bool) {
func (e *compiledAssignExpr) emitGetter(putOnStack bool) {
switch e.operator {
case token.ASSIGN:
if fn, ok := e.right.(*compiledFunctionLiteral); ok {
if fn.name == nil {
if id, ok := e.left.(*compiledIdentifierExpr); ok {
fn.lhsName = id.name
}
}
}
e.left.emitSetter(e.right, putOnStack)
case token.PLUS:
e.left.emitUnary(nil, func() {
Expand Down Expand Up @@ -1065,14 +1050,14 @@ func (e *compiledFunctionLiteral) emitGetter(putOnStack bool) {
}
}, item.Initializer, item.Target.Idx0()).emitGetter(true)
e.c.emitPattern(pattern, func(target, init compiledExpr) {
e.c.emitPatternLexicalAssign(target, init, false)
e.c.emitPatternLexicalAssign(target, init)
}, false)
} else if item.Initializer != nil {
markGet := len(e.c.p.code)
e.c.emit(nil)
mark := len(e.c.p.code)
e.c.emit(nil)
e.c.compileExpression(item.Initializer).emitGetter(true)
e.c.emitExpr(e.c.compileExpression(item.Initializer), true)
if firstForwardRef == -1 && (s.isDynamic() || s.bindings[i].useCount() > 0) {
firstForwardRef = i
}
Expand Down Expand Up @@ -1100,7 +1085,7 @@ func (e *compiledFunctionLiteral) emitGetter(putOnStack bool) {
e.c.emit(createArgsRestStack(paramsCount))
}, rest.Idx0()),
func(target, init compiledExpr) {
e.c.emitPatternLexicalAssign(target, init, false)
e.c.emitPatternLexicalAssign(target, init)
})
}
if firstForwardRef != -1 {
Expand Down Expand Up @@ -1471,14 +1456,6 @@ func (c *compiler) emitConst(expr compiledExpr, putOnStack bool) {
}
}

func (c *compiler) emitExpr(expr compiledExpr, putOnStack bool) {
if expr.constant() {
c.emitConst(expr, putOnStack)
} else {
expr.emitGetter(putOnStack)
}
}

func (c *compiler) evalConst(expr compiledExpr) (Value, *Exception) {
if expr, ok := expr.(*compiledLiteral); ok {
return expr.val, nil
Expand Down Expand Up @@ -1825,7 +1802,7 @@ func (e *compiledObjectLiteral) emitGetter(putOnStack bool) {
}
if computed {
e.c.emit(_toPropertyKey{})
valueExpr.emitGetter(true)
e.c.emitExpr(valueExpr, true)
switch prop.Kind {
case ast.PropertyKindValue, ast.PropertyKindMethod:
if anonFn != nil {
Expand All @@ -1852,7 +1829,7 @@ func (e *compiledObjectLiteral) emitGetter(putOnStack bool) {
if anonFn != nil && !isProto {
anonFn.lhsName = key
}
valueExpr.emitGetter(true)
e.c.emitExpr(valueExpr, true)
switch prop.Kind {
case ast.PropertyKindValue:
if isProto {
Expand Down Expand Up @@ -1912,7 +1889,7 @@ func (e *compiledArrayLiteral) emitGetter(putOnStack bool) {
e.c.emit(pushArraySpread)
} else {
if v != nil {
e.c.compileExpression(v).emitGetter(true)
e.c.emitExpr(e.c.compileExpression(v), true)
} else {
e.c.emit(loadNil)
}
Expand Down Expand Up @@ -2195,6 +2172,14 @@ func (e *compiledArrayAssignmentPattern) emitGetter(putOnStack bool) {
}
}

func (c *compiler) emitExpr(expr compiledExpr, putOnStack bool) {
if expr.constant() {
c.emitConst(expr, putOnStack)
} else {
expr.emitGetter(putOnStack)
}
}

func (c *compiler) emitNamed(expr compiledExpr, name unistring.String) {
if en, ok := expr.(interface {
emitNamed(name unistring.String)
Expand All @@ -2205,6 +2190,14 @@ func (c *compiler) emitNamed(expr compiledExpr, name unistring.String) {
}
}

func (c *compiler) emitNamedOrConst(expr compiledExpr, name unistring.String) {
if expr.constant() {
c.emitConst(expr, true)
} else {
c.emitNamed(expr, name)
}
}

func (e *compiledFunctionLiteral) emitNamed(name unistring.String) {
e.lhsName = name
e.emitGetter(true)
Expand Down Expand Up @@ -2327,7 +2320,7 @@ func (e *compiledPatternInitExpr) emitGetter(putOnStack bool) {
if e.def != nil {
mark := len(e.c.p.code)
e.c.emit(nil)
e.def.emitGetter(true)
e.c.emitExpr(e.def, true)
e.c.p.code[mark] = jdef(len(e.c.p.code) - mark)
}
}
Expand All @@ -2337,7 +2330,7 @@ func (e *compiledPatternInitExpr) emitNamed(name unistring.String) {
if e.def != nil {
mark := len(e.c.p.code)
e.c.emit(nil)
e.c.emitNamed(e.def, name)
e.c.emitNamedOrConst(e.def, name)
e.c.p.code[mark] = jdef(len(e.c.p.code) - mark)
}
}
Expand Down
64 changes: 36 additions & 28 deletions compiler_stmt.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,6 @@ import (
)

func (c *compiler) compileStatement(v ast.Statement, needResult bool) {
// log.Printf("compileStatement(): %T", v)

switch v := v.(type) {
case *ast.BlockStatement:
Expand Down Expand Up @@ -158,7 +157,7 @@ func (c *compiler) compileTryStatement(v *ast.TryStatement, needResult bool) {
if pattern, ok := v.Catch.Parameter.(ast.Pattern); ok {
c.scope.bindings[0].emitGet()
c.emitPattern(pattern, func(target, init compiledExpr) {
c.emitPatternLexicalAssign(target, init, false)
c.emitPatternLexicalAssign(target, init)
}, false)
}
for _, decl := range funcs {
Expand Down Expand Up @@ -392,7 +391,7 @@ func (c *compiler) compileForInto(into ast.ForInto, needResult bool) (enter *ent
c.createLexicalBinding(target, into.IsConst)
c.emit(enumGet)
c.emitPattern(target, func(target, init compiledExpr) {
c.emitPatternLexicalAssign(target, init, into.IsConst)
c.emitPatternLexicalAssign(target, init)
}, false)
default:
c.throwSyntaxError(int(into.Idx)-1, "Unsupported ForBinding: %T", into.Target)
Expand Down Expand Up @@ -725,7 +724,7 @@ func (c *compiler) compileIfStatement(v *ast.IfStatement, needResult bool) {

func (c *compiler) compileReturnStatement(v *ast.ReturnStatement) {
if v.Argument != nil {
c.compileExpression(v.Argument).emitGetter(true)
c.emitExpr(c.compileExpression(v.Argument), true)
} else {
c.emit(loadUndef)
}
Expand Down Expand Up @@ -754,10 +753,17 @@ func (c *compiler) checkVarConflict(name unistring.String, offset int) {
func (c *compiler) emitVarAssign(name unistring.String, offset int, init compiledExpr) {
c.checkVarConflict(name, offset)
if init != nil {
c.emitVarRef(name, offset)
c.emitNamed(init, name)
c.p.addSrcMap(offset)
c.emit(initValueP)
b, noDyn := c.scope.lookupName(name)
if noDyn {
c.emitNamedOrConst(init, name)
c.p.addSrcMap(offset)
b.emitInit()
} else {
c.emitVarRef(name, offset, b)
c.emitNamedOrConst(init, name)
c.p.addSrcMap(offset)
c.emit(initValueP)
}
}
}

Expand All @@ -773,16 +779,16 @@ func (c *compiler) compileVarBinding(expr *ast.Binding) {
}
}

func (c *compiler) emitLexicalAssign(name unistring.String, offset int, init compiledExpr, isConst bool) {
func (c *compiler) emitLexicalAssign(name unistring.String, offset int, init compiledExpr) {
b := c.scope.boundNames[name]
if b == nil {
panic("Lexical declaration for an unbound name")
}
if init != nil {
c.emitNamed(init, name)
c.emitNamedOrConst(init, name)
c.p.addSrcMap(offset)
} else {
if isConst {
if b.isConst {
c.throwSyntaxError(offset, "Missing initializer in const declaration")
}
c.emit(loadUndef)
Expand All @@ -799,29 +805,37 @@ func (c *compiler) emitPatternVarAssign(target, init compiledExpr) {
c.emitVarAssign(id.name, id.offset, init)
}

func (c *compiler) emitPatternLexicalAssign(target, init compiledExpr, isConst bool) {
func (c *compiler) emitPatternLexicalAssign(target, init compiledExpr) {
id := target.(*compiledIdentifierExpr)
c.emitLexicalAssign(id.name, id.offset, init, isConst)
c.emitLexicalAssign(id.name, id.offset, init)
}

func (c *compiler) emitPatternAssign(target, init compiledExpr) {
target.emitRef()
if id, ok := target.(*compiledIdentifierExpr); ok {
c.emitNamed(init, id.name)
b, noDyn := c.scope.lookupName(id.name)
if noDyn {
c.emitNamedOrConst(init, id.name)
b.emitSetP()
} else {
c.emitVarRef(id.name, id.offset, b)
c.emitNamedOrConst(init, id.name)
c.emit(putValueP)
}
} else {
init.emitGetter(true)
target.emitRef()
c.emitExpr(init, true)
c.emit(putValueP)
}
c.emit(initValueP)
}

func (c *compiler) compileLexicalBinding(expr *ast.Binding, isConst bool) {
func (c *compiler) compileLexicalBinding(expr *ast.Binding) {
switch target := expr.Target.(type) {
case *ast.Identifier:
c.emitLexicalAssign(target.Name, int(target.Idx)-1, c.compileExpression(expr.Initializer), isConst)
c.emitLexicalAssign(target.Name, int(target.Idx)-1, c.compileExpression(expr.Initializer))
case ast.Pattern:
c.compileExpression(expr.Initializer).emitGetter(true)
c.emitPattern(target, func(target, init compiledExpr) {
c.emitPatternLexicalAssign(target, init, isConst)
c.emitPatternLexicalAssign(target, init)
}, false)
default:
c.throwSyntaxError(int(target.Idx0()-1), "unsupported lexical binding target: %T", target)
Expand All @@ -835,9 +849,8 @@ func (c *compiler) compileVariableStatement(v *ast.VariableStatement) {
}

func (c *compiler) compileLexicalDeclaration(v *ast.LexicalDeclaration) {
isConst := v.Token == token.CONST
for _, e := range v.List {
c.compileLexicalBinding(e, isConst)
c.compileLexicalBinding(e)
}
}

Expand Down Expand Up @@ -964,12 +977,7 @@ func (c *compiler) compileBlockStatement(v *ast.BlockStatement, needResult bool)
}

func (c *compiler) compileExpressionStatement(v *ast.ExpressionStatement, needResult bool) {
expr := c.compileExpression(v.Expression)
if expr.constant() {
c.emitConst(expr, needResult)
} else {
expr.emitGetter(needResult)
}
c.emitExpr(c.compileExpression(v.Expression), needResult)
if needResult {
c.emit(saveResult)
}
Expand Down
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