forked from TrueCloudLab/neoneo-go
763 lines
18 KiB
Go
763 lines
18 KiB
Go
package compiler
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import (
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"bytes"
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"encoding/binary"
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"go/ast"
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"go/constant"
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"go/token"
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"go/types"
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"log"
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"strings"
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"github.com/CityOfZion/neo-go/pkg/crypto"
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"github.com/CityOfZion/neo-go/pkg/vm"
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)
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// The identifier of the entry function. Default set to Main.
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const mainIdent = "Main"
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type codegen struct {
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// Information about the program with all its dependencies.
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buildInfo *buildInfo
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// prog holds the output buffer
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prog *bytes.Buffer
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// Type information
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typeInfo *types.Info
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// A mapping of func identifiers with their scope.
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funcs map[string]*funcScope
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// Current funcScope being converted.
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scope *funcScope
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// Label table for recording jump destinations.
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l []int
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}
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// newLabel creates a new label to jump to
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func (c *codegen) newLabel() (l int) {
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l = len(c.l)
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c.l = append(c.l, -1)
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return
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}
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func (c *codegen) setLabel(l int) {
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c.l[l] = c.pc() + 1
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}
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// pc return the program offset off the last instruction.
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func (c *codegen) pc() int {
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return c.prog.Len() - 1
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}
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func (c *codegen) emitLoadConst(t types.TypeAndValue) {
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switch typ := t.Type.Underlying().(type) {
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case *types.Basic:
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switch typ.Kind() {
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case types.Int, types.UntypedInt:
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val, _ := constant.Int64Val(t.Value)
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emitInt(c.prog, val)
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case types.String, types.UntypedString:
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val := constant.StringVal(t.Value)
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emitString(c.prog, val)
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case types.Bool, types.UntypedBool:
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val := constant.BoolVal(t.Value)
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emitBool(c.prog, val)
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case types.Byte:
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val, _ := constant.Int64Val(t.Value)
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b := byte(val)
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emitBytes(c.prog, []byte{b})
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default:
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log.Fatalf("compiler don't know how to convert this basic type: %v", t)
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}
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default:
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log.Fatalf("compiler don't know how to convert this constant: %v", t)
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}
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}
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func (c *codegen) emitLoadLocal(name string) {
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pos := c.scope.loadLocal(name)
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if pos < 0 {
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log.Fatalf("cannot load local variable with position: %d", pos)
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}
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c.emitLoadLocalPos(pos)
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}
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func (c *codegen) emitLoadLocalPos(pos int) {
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emitOpcode(c.prog, vm.FROMALTSTACK)
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emitOpcode(c.prog, vm.DUP)
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emitOpcode(c.prog, vm.TOALTSTACK)
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emitInt(c.prog, int64(pos))
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emitOpcode(c.prog, vm.PICKITEM)
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}
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func (c *codegen) emitStoreLocal(pos int) {
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emitOpcode(c.prog, vm.FROMALTSTACK)
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emitOpcode(c.prog, vm.DUP)
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emitOpcode(c.prog, vm.TOALTSTACK)
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if pos < 0 {
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log.Fatalf("invalid position to store local: %d", pos)
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}
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emitInt(c.prog, int64(pos))
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emitInt(c.prog, 2)
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emitOpcode(c.prog, vm.ROLL)
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emitOpcode(c.prog, vm.SETITEM)
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}
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func (c *codegen) emitLoadField(i int) {
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emitInt(c.prog, int64(i))
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emitOpcode(c.prog, vm.PICKITEM)
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}
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func (c *codegen) emitStoreStructField(i int) {
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emitInt(c.prog, int64(i))
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emitOpcode(c.prog, vm.ROT)
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emitOpcode(c.prog, vm.SETITEM)
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}
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// convertGlobals will traverse the AST and only convert global declarations.
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// If we call this in convertFuncDecl then it will load all global variables
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// into the scope of the function.
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func (c *codegen) convertGlobals(f ast.Node) {
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ast.Inspect(f, func(node ast.Node) bool {
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switch n := node.(type) {
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case *ast.FuncDecl:
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return false
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case *ast.GenDecl:
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ast.Walk(c, n)
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}
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return true
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})
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}
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func (c *codegen) convertFuncDecl(file ast.Node, decl *ast.FuncDecl) {
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var (
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f *funcScope
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ok bool
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)
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f, ok = c.funcs[decl.Name.Name]
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if ok {
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c.setLabel(f.label)
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} else {
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f = c.newFunc(decl)
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}
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c.scope = f
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ast.Inspect(decl, c.scope.analyzeVoidCalls) // @OPTIMIZE
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// All globals copied into the scope of the function need to be added
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// to the stack size of the function.
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emitInt(c.prog, f.stackSize()+countGlobals(file))
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emitOpcode(c.prog, vm.NEWARRAY)
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emitOpcode(c.prog, vm.TOALTSTACK)
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// We need to handle methods, which in Go, is just syntactic sugar.
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// The method receiver will be passed in as first argument.
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// We check if this declaration has a receiver and load it into scope.
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//
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// FIXME: For now we will hard cast this to a struct. We can later fine tune this
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// to support other types.
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if decl.Recv != nil {
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for _, arg := range decl.Recv.List {
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ident := arg.Names[0]
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// Currently only method receives for struct types is supported.
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_, ok := c.typeInfo.Defs[ident].Type().Underlying().(*types.Struct)
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if !ok {
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log.Fatal("method receives for non-struct types is not yet supported")
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}
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l := c.scope.newLocal(ident.Name)
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c.emitStoreLocal(l)
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}
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}
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// Load the arguments in scope.
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for _, arg := range decl.Type.Params.List {
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name := arg.Names[0].Name // for now.
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l := c.scope.newLocal(name)
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c.emitStoreLocal(l)
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}
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// Load in all the global variables in to the scope of the function.
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// This is not necessary for syscalls.
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if !isSyscall(f.name) {
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c.convertGlobals(file)
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}
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ast.Walk(c, decl.Body)
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// If this function returns the void (no return stmt) we will cleanup its junk on the stack.
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if !hasReturnStmt(decl) {
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emitOpcode(c.prog, vm.FROMALTSTACK)
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emitOpcode(c.prog, vm.DROP)
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emitOpcode(c.prog, vm.RET)
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}
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}
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func (c *codegen) Visit(node ast.Node) ast.Visitor {
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switch n := node.(type) {
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// General declarations.
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// var (
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// x = 2
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// )
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case *ast.GenDecl:
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for _, spec := range n.Specs {
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switch t := spec.(type) {
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case *ast.ValueSpec:
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for i, val := range t.Values {
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ast.Walk(c, val)
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l := c.scope.newLocal(t.Names[i].Name)
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c.emitStoreLocal(l)
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}
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}
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}
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return nil
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case *ast.AssignStmt:
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for i := 0; i < len(n.Lhs); i++ {
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switch t := n.Lhs[i].(type) {
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case *ast.Ident:
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switch n.Tok {
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case token.ADD_ASSIGN, token.SUB_ASSIGN, token.MUL_ASSIGN, token.QUO_ASSIGN:
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c.emitLoadLocal(t.Name)
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ast.Walk(c, n.Rhs[0]) // can only add assign to 1 expr on the RHS
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c.convertToken(n.Tok)
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l := c.scope.loadLocal(t.Name)
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c.emitStoreLocal(l)
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default:
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ast.Walk(c, n.Rhs[i])
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l := c.scope.loadLocal(t.Name)
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c.emitStoreLocal(l)
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}
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case *ast.SelectorExpr:
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switch expr := t.X.(type) {
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case *ast.Ident:
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ast.Walk(c, n.Rhs[i])
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typ := c.typeInfo.ObjectOf(expr).Type().Underlying()
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if strct, ok := typ.(*types.Struct); ok {
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c.emitLoadLocal(expr.Name) // load the struct
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i := indexOfStruct(strct, t.Sel.Name) // get the index of the field
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c.emitStoreStructField(i) // store the field
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}
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default:
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log.Fatal("nested selector assigns not supported yet")
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}
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}
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}
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return nil
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case *ast.ReturnStmt:
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if len(n.Results) > 1 {
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log.Fatal("multiple returns not supported.")
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}
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// @OPTIMIZE: We could skip these 3 instructions for each return statement.
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// To be backwards compatible we will put them them in.
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// See issue #65 (https://github.com/CityOfZion/neo-go/issues/65)
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l := c.newLabel()
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emitJmp(c.prog, vm.JMP, int16(l))
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c.setLabel(l)
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if len(n.Results) > 0 {
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ast.Walk(c, n.Results[0])
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}
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emitOpcode(c.prog, vm.NOP) // @OPTIMIZE
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emitOpcode(c.prog, vm.FROMALTSTACK)
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emitOpcode(c.prog, vm.DROP) // Cleanup the stack.
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emitOpcode(c.prog, vm.RET)
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return nil
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case *ast.IfStmt:
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lIf := c.newLabel()
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lElse := c.newLabel()
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if n.Cond != nil {
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ast.Walk(c, n.Cond)
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emitJmp(c.prog, vm.JMPIFNOT, int16(lElse))
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}
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c.setLabel(lIf)
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ast.Walk(c, n.Body)
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if n.Else != nil {
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// TODO: handle else statements.
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// emitJmp(c.prog, vm.JMP, int16(lEnd))
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}
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c.setLabel(lElse)
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if n.Else != nil {
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ast.Walk(c, n.Else)
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}
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return nil
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case *ast.BasicLit:
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c.emitLoadConst(c.typeInfo.Types[n])
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return nil
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case *ast.Ident:
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if isIdentBool(n) {
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c.emitLoadConst(makeBoolFromIdent(n, c.typeInfo))
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} else {
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c.emitLoadLocal(n.Name)
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}
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return nil
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case *ast.CompositeLit:
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var typ types.Type
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switch t := n.Type.(type) {
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case *ast.Ident:
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typ = c.typeInfo.ObjectOf(t).Type().Underlying()
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case *ast.SelectorExpr:
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typ = c.typeInfo.ObjectOf(t.Sel).Type().Underlying()
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default:
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ln := len(n.Elts)
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// ByteArrays need a different approach then normal arrays.
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if isByteArray(n, c.typeInfo) {
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c.convertByteArray(n)
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return nil
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}
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for i := ln - 1; i >= 0; i-- {
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c.emitLoadConst(c.typeInfo.Types[n.Elts[i]])
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}
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emitInt(c.prog, int64(ln))
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emitOpcode(c.prog, vm.PACK)
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return nil
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}
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switch typ.(type) {
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case *types.Struct:
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c.convertStruct(n)
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}
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return nil
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case *ast.BinaryExpr:
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switch n.Op {
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case token.LAND:
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ast.Walk(c, n.X)
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emitJmp(c.prog, vm.JMPIFNOT, int16(len(c.l)-1))
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ast.Walk(c, n.Y)
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return nil
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case token.LOR:
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ast.Walk(c, n.X)
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emitJmp(c.prog, vm.JMPIF, int16(len(c.l)-2))
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ast.Walk(c, n.Y)
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return nil
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default:
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// The AST package will try to resolve all basic literals for us.
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// If the typeinfo.Value is not nil we know that the expr is resolved
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// and needs no further action. e.g. x := 2 + 2 + 2 will be resolved to 6.
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// NOTE: Constants will also be automatically resolved be the AST parser.
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// example:
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// const x = 10
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// x + 2 will results into 12
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if tinfo := c.typeInfo.Types[n]; tinfo.Value != nil {
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c.emitLoadConst(tinfo)
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return nil
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}
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ast.Walk(c, n.X)
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ast.Walk(c, n.Y)
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c.convertToken(n.Op)
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return nil
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}
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case *ast.CallExpr:
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var (
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f *funcScope
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ok bool
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numArgs = len(n.Args)
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isBuiltin = isBuiltin(n.Fun)
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)
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switch fun := n.Fun.(type) {
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case *ast.Ident:
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f, ok = c.funcs[fun.Name]
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if !ok && !isBuiltin {
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log.Fatalf("could not resolve function %s", fun.Name)
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}
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case *ast.SelectorExpr:
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// If this is a method call we need to walk the AST to load the struct locally.
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// Otherwise this is a function call from a imported package and we can call it
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// directly.
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if c.typeInfo.Selections[fun] != nil {
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ast.Walk(c, fun.X)
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// Dont forget to add 1 extra argument when its a method.
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numArgs++
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}
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f, ok = c.funcs[fun.Sel.Name]
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if !ok {
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log.Fatalf("could not resolve function %s", fun.Sel.Name)
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}
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case *ast.ArrayType:
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// For now we will assume that there is only 1 argument passed which
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// will be a basic literal (string kind). This only to handle string
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// to byte slice conversions. E.G. []byte("foobar")
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arg := n.Args[0].(*ast.BasicLit)
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c.emitLoadConst(c.typeInfo.Types[arg])
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return nil
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}
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// Handle the arguments
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for _, arg := range n.Args {
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ast.Walk(c, arg)
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}
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// Do not swap for builtin functions.
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if !isBuiltin {
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if numArgs == 2 {
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emitOpcode(c.prog, vm.SWAP)
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}
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if numArgs == 3 {
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emitInt(c.prog, 2)
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emitOpcode(c.prog, vm.XSWAP)
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}
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}
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// c# compiler adds a NOP (0x61) before every function call. Dont think its relevant
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// and we could easily removed it, but to be consistent with the original compiler I
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// will put them in. ^^
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emitOpcode(c.prog, vm.NOP)
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// Check builtin first to avoid nil pointer on funcScope!
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switch {
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case isBuiltin:
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// Use the ident to check, builtins are not in func scopes.
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// We can be sure builtins are of type *ast.Ident.
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c.convertBuiltin(n)
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case isSyscall(f.name):
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c.convertSyscall(f.name)
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default:
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emitCall(c.prog, vm.CALL, int16(f.label))
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}
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// If we are not assigning this function to a variable we need to drop
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// (cleanup) the top stack item. It's not a void but you get the point \o/.
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if _, ok := c.scope.voidCalls[n]; ok {
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emitOpcode(c.prog, vm.DROP)
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}
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return nil
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case *ast.SelectorExpr:
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switch t := n.X.(type) {
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case *ast.Ident:
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typ := c.typeInfo.ObjectOf(t).Type().Underlying()
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if strct, ok := typ.(*types.Struct); ok {
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c.emitLoadLocal(t.Name) // load the struct
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i := indexOfStruct(strct, n.Sel.Name)
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c.emitLoadField(i) // load the field
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}
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default:
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log.Fatal("nested selectors not supported yet")
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}
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return nil
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case *ast.UnaryExpr:
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ast.Walk(c, n.X)
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c.convertToken(n.Op)
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return nil
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case *ast.IncDecStmt:
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ast.Walk(c, n.X)
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c.convertToken(n.Tok)
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// For now only identifiers are supported for (post) for stmts.
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// for i := 0; i < 10; i++ {}
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// Where the post stmt is ( i++ )
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if ident, ok := n.X.(*ast.Ident); ok {
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pos := c.scope.loadLocal(ident.Name)
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c.emitStoreLocal(pos)
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}
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return nil
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case *ast.IndexExpr:
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// Walk the expression, this could be either an Ident or SelectorExpr.
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// This will load local whatever X is.
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ast.Walk(c, n.X)
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switch n.Index.(type) {
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case *ast.BasicLit:
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t := c.typeInfo.Types[n.Index]
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val, _ := constant.Int64Val(t.Value)
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c.emitLoadField(int(val))
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default:
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ast.Walk(c, n.Index)
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emitOpcode(c.prog, vm.PICKITEM) // just pickitem here
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}
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return nil
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case *ast.ForStmt:
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var (
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fstart = c.newLabel()
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fend = c.newLabel()
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)
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// Walk the initializer and condition.
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ast.Walk(c, n.Init)
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// Set label and walk the condition.
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c.setLabel(fstart)
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ast.Walk(c, n.Cond)
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// Jump if the condition is false
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emitJmp(c.prog, vm.JMPIFNOT, int16(fend))
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// Walk body followed by the iterator (post stmt).
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ast.Walk(c, n.Body)
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ast.Walk(c, n.Post)
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// Jump back to condition.
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emitJmp(c.prog, vm.JMP, int16(fstart))
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c.setLabel(fend)
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return nil
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// We dont really care about assertions for the core logic.
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// The only thing we need is to please the compiler type checking.
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// For this to work properly, we only need to walk the expression
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// not the assertion type.
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case *ast.TypeAssertExpr:
|
|
ast.Walk(c, n.X)
|
|
return nil
|
|
}
|
|
return c
|
|
}
|
|
|
|
func (c *codegen) convertSyscall(name string) {
|
|
api, ok := syscalls[name]
|
|
if !ok {
|
|
log.Fatalf("unknown VM syscall api: %s", name)
|
|
}
|
|
emitSyscall(c.prog, api)
|
|
emitOpcode(c.prog, vm.NOP) // @OPTIMIZE
|
|
}
|
|
|
|
func (c *codegen) convertBuiltin(expr *ast.CallExpr) {
|
|
var name string
|
|
switch t := expr.Fun.(type) {
|
|
case *ast.Ident:
|
|
name = t.Name
|
|
case *ast.SelectorExpr:
|
|
name = t.Sel.Name
|
|
}
|
|
|
|
switch name {
|
|
case "len":
|
|
arg := expr.Args[0]
|
|
typ := c.typeInfo.Types[arg].Type
|
|
if isStringType(typ) {
|
|
emitOpcode(c.prog, vm.SIZE)
|
|
} else {
|
|
emitOpcode(c.prog, vm.ARRAYSIZE)
|
|
}
|
|
case "append":
|
|
emitOpcode(c.prog, vm.APPEND)
|
|
case "SHA256":
|
|
emitOpcode(c.prog, vm.SHA256)
|
|
case "SHA1":
|
|
emitOpcode(c.prog, vm.SHA1)
|
|
case "Hash256":
|
|
emitOpcode(c.prog, vm.HASH256)
|
|
case "Hash160":
|
|
emitOpcode(c.prog, vm.HASH160)
|
|
case "FromAddress":
|
|
// We can be sure that this is a ast.BasicLit just containing a simple
|
|
// address string. Note that the string returned from calling Value will
|
|
// contain double quotes that need to be stripped.
|
|
addressStr := expr.Args[0].(*ast.BasicLit).Value
|
|
addressStr = strings.Replace(addressStr, "\"", "", 2)
|
|
uint160, err := crypto.Uint160DecodeAddress(addressStr)
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
bytes := uint160.Bytes()
|
|
emitBytes(c.prog, bytes)
|
|
}
|
|
}
|
|
|
|
func (c *codegen) convertByteArray(lit *ast.CompositeLit) {
|
|
buf := make([]byte, len(lit.Elts))
|
|
for i := 0; i < len(lit.Elts); i++ {
|
|
t := c.typeInfo.Types[lit.Elts[i]]
|
|
val, _ := constant.Int64Val(t.Value)
|
|
buf[i] = byte(val)
|
|
}
|
|
emitBytes(c.prog, buf)
|
|
}
|
|
|
|
func (c *codegen) convertStruct(lit *ast.CompositeLit) {
|
|
// Create a new structScope to initialize and store
|
|
// the positions of its variables.
|
|
strct, ok := c.typeInfo.TypeOf(lit).Underlying().(*types.Struct)
|
|
if !ok {
|
|
log.Fatalf("the given literal is not of type struct: %v", lit)
|
|
}
|
|
|
|
emitOpcode(c.prog, vm.NOP)
|
|
emitInt(c.prog, int64(strct.NumFields()))
|
|
emitOpcode(c.prog, vm.NEWSTRUCT)
|
|
emitOpcode(c.prog, vm.TOALTSTACK)
|
|
|
|
// We need to locally store all the fields, even if they are not initialized.
|
|
// We will initialize all fields to their "zero" value.
|
|
for i := 0; i < strct.NumFields(); i++ {
|
|
sField := strct.Field(i)
|
|
fieldAdded := false
|
|
|
|
// Fields initialized by the program.
|
|
for _, field := range lit.Elts {
|
|
f := field.(*ast.KeyValueExpr)
|
|
fieldName := f.Key.(*ast.Ident).Name
|
|
|
|
if sField.Name() == fieldName {
|
|
ast.Walk(c, f.Value)
|
|
pos := indexOfStruct(strct, fieldName)
|
|
c.emitStoreLocal(pos)
|
|
fieldAdded = true
|
|
break
|
|
}
|
|
}
|
|
if fieldAdded {
|
|
continue
|
|
}
|
|
|
|
typeAndVal := typeAndValueForField(sField)
|
|
c.emitLoadConst(typeAndVal)
|
|
c.emitStoreLocal(i)
|
|
}
|
|
emitOpcode(c.prog, vm.FROMALTSTACK)
|
|
}
|
|
|
|
func (c *codegen) convertToken(tok token.Token) {
|
|
switch tok {
|
|
case token.ADD_ASSIGN:
|
|
emitOpcode(c.prog, vm.ADD)
|
|
case token.SUB_ASSIGN:
|
|
emitOpcode(c.prog, vm.SUB)
|
|
case token.MUL_ASSIGN:
|
|
emitOpcode(c.prog, vm.MUL)
|
|
case token.QUO_ASSIGN:
|
|
emitOpcode(c.prog, vm.DIV)
|
|
case token.ADD:
|
|
emitOpcode(c.prog, vm.ADD)
|
|
case token.SUB:
|
|
emitOpcode(c.prog, vm.SUB)
|
|
case token.MUL:
|
|
emitOpcode(c.prog, vm.MUL)
|
|
case token.QUO:
|
|
emitOpcode(c.prog, vm.DIV)
|
|
case token.LSS:
|
|
emitOpcode(c.prog, vm.LT)
|
|
case token.LEQ:
|
|
emitOpcode(c.prog, vm.LTE)
|
|
case token.GTR:
|
|
emitOpcode(c.prog, vm.GT)
|
|
case token.GEQ:
|
|
emitOpcode(c.prog, vm.GTE)
|
|
case token.EQL:
|
|
emitOpcode(c.prog, vm.NUMEQUAL)
|
|
case token.NEQ:
|
|
emitOpcode(c.prog, vm.NUMNOTEQUAL)
|
|
case token.DEC:
|
|
emitOpcode(c.prog, vm.DEC)
|
|
case token.INC:
|
|
emitOpcode(c.prog, vm.INC)
|
|
case token.NOT:
|
|
emitOpcode(c.prog, vm.NOT)
|
|
default:
|
|
log.Fatalf("compiler could not convert token: %s", tok)
|
|
}
|
|
}
|
|
|
|
func (c *codegen) newFunc(decl *ast.FuncDecl) *funcScope {
|
|
f := newFuncScope(decl, c.newLabel())
|
|
c.funcs[f.name] = f
|
|
return f
|
|
}
|
|
|
|
// CodeGen is the function that compiles the program to bytecode.
|
|
func CodeGen(info *buildInfo) (*bytes.Buffer, error) {
|
|
pkg := info.program.Package(info.initialPackage)
|
|
c := &codegen{
|
|
buildInfo: info,
|
|
prog: new(bytes.Buffer),
|
|
l: []int{},
|
|
funcs: map[string]*funcScope{},
|
|
typeInfo: &pkg.Info,
|
|
}
|
|
|
|
// Resolve the entrypoint of the program
|
|
main, mainFile := resolveEntryPoint(mainIdent, pkg)
|
|
if main == nil {
|
|
log.Fatal("could not find func main. did you forgot to declare it?")
|
|
}
|
|
|
|
funUsage := analyzeFuncUsage(info.program.AllPackages)
|
|
|
|
// Bring all imported functions into scope
|
|
for _, pkg := range info.program.AllPackages {
|
|
for _, f := range pkg.Files {
|
|
c.resolveFuncDecls(f)
|
|
}
|
|
}
|
|
|
|
// convert the entry point first
|
|
c.convertFuncDecl(mainFile, main)
|
|
|
|
// Generate the code for the program
|
|
for _, pkg := range info.program.AllPackages {
|
|
c.typeInfo = &pkg.Info
|
|
|
|
for _, f := range pkg.Files {
|
|
for _, decl := range f.Decls {
|
|
switch n := decl.(type) {
|
|
case *ast.FuncDecl:
|
|
// Dont convert the function if its not used. This will save a lot
|
|
// of bytecode space.
|
|
if n.Name.Name != mainIdent && funUsage.funcUsed(n.Name.Name) {
|
|
c.convertFuncDecl(f, n)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
c.writeJumps()
|
|
|
|
return c.prog, nil
|
|
}
|
|
|
|
func (c *codegen) resolveFuncDecls(f *ast.File) {
|
|
for _, decl := range f.Decls {
|
|
switch n := decl.(type) {
|
|
case *ast.FuncDecl:
|
|
if n.Name.Name != mainIdent {
|
|
c.newFunc(n)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *codegen) writeJumps() {
|
|
b := c.prog.Bytes()
|
|
for i, op := range b {
|
|
j := i + 1
|
|
switch vm.Instruction(op) {
|
|
case vm.JMP, vm.JMPIFNOT, vm.JMPIF, vm.CALL:
|
|
index := int16(binary.LittleEndian.Uint16(b[j : j+2]))
|
|
if int(index) > len(c.l) || int(index) < 0 {
|
|
continue
|
|
}
|
|
offset := uint16(c.l[index] - i)
|
|
binary.LittleEndian.PutUint16(b[j:j+2], offset)
|
|
}
|
|
}
|
|
}
|