neoneo-go/pkg/vm/compiler/codegen.go
Anthony De Meulemeester 23cfebf621
Compiler (#23)
* implemented add, mul, div, sub assign for identifiers.

* Implemented struct field initialization.

* Implemented imports

* Implemented storage VM API (interop layer) + additional bug fixes when encountered.

* Bumped version 0.12.0

* fixed double point extension on compiled output file.

* Fixed bug where callExpr in returns where added to voidCall

* fixed binExpr compare equal

* Check the env for the gopath first

* removed travis.yml

* custom types + implemented general declarations.

* commented out the storage test to make the build pass
2018-02-24 10:06:48 +01:00

610 lines
14 KiB
Go

package compiler
import (
"bytes"
"encoding/binary"
"go/ast"
"go/constant"
"go/token"
"go/types"
"log"
"github.com/CityOfZion/neo-go/pkg/vm"
)
const mainIdent = "Main"
type codegen struct {
prog *bytes.Buffer
// Type information
typeInfo *types.Info
// a mapping of func identifiers with its scope.
funcs map[string]*funcScope
// current function being generated
fctx *funcScope
// Label table for recording jump destinations.
l []int
}
// newLabel creates a new label to jump to
func (c *codegen) newLabel() (l int) {
l = len(c.l)
c.l = append(c.l, -1)
return
}
func (c *codegen) setLabel(l int) {
c.l[l] = c.pc() + 1
}
// pc return the program offset off the last instruction.
func (c *codegen) pc() int {
return c.prog.Len() - 1
}
func (c *codegen) emitLoadConst(t types.TypeAndValue) {
switch typ := t.Type.Underlying().(type) {
case *types.Basic:
switch typ.Kind() {
case types.Int:
val, _ := constant.Int64Val(t.Value)
emitInt(c.prog, val)
case types.String:
val := constant.StringVal(t.Value)
emitString(c.prog, val)
case types.Bool, types.UntypedBool:
val := constant.BoolVal(t.Value)
emitBool(c.prog, val)
}
default:
log.Fatalf("compiler don't know how to convert this constant: %v", t)
}
}
func (c *codegen) emitLoadLocal(name string) {
pos := c.fctx.loadLocal(name)
if pos < 0 {
log.Fatalf("cannot load local variable with position: %d", pos)
}
emitOpcode(c.prog, vm.Ofromaltstack)
emitOpcode(c.prog, vm.Odup)
emitOpcode(c.prog, vm.Otoaltstack)
emitInt(c.prog, int64(pos))
emitOpcode(c.prog, vm.Opickitem)
}
func (c *codegen) emitLoadStructField(sName, fName string) {
strct := c.fctx.loadStruct(sName)
pos := strct.loadField(fName)
emitInt(c.prog, int64(pos))
emitOpcode(c.prog, vm.Opickitem)
}
func (c *codegen) emitStoreLocal(pos int) {
emitOpcode(c.prog, vm.Ofromaltstack)
emitOpcode(c.prog, vm.Odup)
emitOpcode(c.prog, vm.Otoaltstack)
if pos < 0 {
log.Fatalf("invalid position to store local: %d", pos)
}
emitInt(c.prog, int64(pos))
emitInt(c.prog, 2)
emitOpcode(c.prog, vm.Oroll)
emitOpcode(c.prog, vm.Osetitem)
}
func (c *codegen) emitStoreStructField(sName, fName string) {
strct := c.fctx.loadStruct(sName)
pos := strct.loadField(fName)
emitInt(c.prog, int64(pos))
emitOpcode(c.prog, vm.Orot)
emitOpcode(c.prog, vm.Osetitem)
}
func (c *codegen) convertFuncDecl(decl *ast.FuncDecl) {
var (
f *funcScope
ok bool
)
f, ok = c.funcs[decl.Name.Name]
if ok {
c.setLabel(f.label)
} else {
f = c.newFunc(decl)
}
c.fctx = f
ast.Inspect(decl, c.fctx.analyzeVoidCalls)
emitInt(c.prog, f.stackSize())
emitOpcode(c.prog, vm.Onewarray)
emitOpcode(c.prog, vm.Otoaltstack)
// We need to handle methods, which in Go, is just syntactic sugar.
// The method receiver will be passed in as first argument.
// We check if this declaration has a receiver and load it into scope.
//
// FIXME: For now we will hard cast this to a struct. We can later finetune this
// to support other types.
if decl.Recv != nil {
for _, arg := range decl.Recv.List {
ident := arg.Names[0]
t, ok := c.typeInfo.Defs[ident].Type().Underlying().(*types.Struct)
if !ok {
log.Fatal("method receiver is not a struct type")
}
c.fctx.newStruct(t)
l := c.fctx.newLocal(ident.Name)
c.emitStoreLocal(l)
}
}
// Load the arguments in scope.
for _, arg := range decl.Type.Params.List {
name := arg.Names[0].Name // for now.
l := c.fctx.newLocal(name)
c.emitStoreLocal(l)
}
ast.Walk(c, decl.Body)
}
func (c *codegen) Visit(node ast.Node) ast.Visitor {
switch n := node.(type) {
// General declarations.
// With value: var x int = 2
// Without value: var x int
case *ast.GenDecl:
switch t := n.Specs[0].(type) {
case *ast.ValueSpec:
if len(t.Values) > 0 {
ast.Walk(c, t.Values[0])
l := c.fctx.newLocal(t.Names[0].Name)
c.emitStoreLocal(l)
}
}
return nil
case *ast.AssignStmt:
for i := 0; i < len(n.Lhs); i++ {
switch t := n.Lhs[i].(type) {
case *ast.Ident:
switch n.Tok {
case token.ADD_ASSIGN, token.SUB_ASSIGN, token.MUL_ASSIGN, token.QUO_ASSIGN:
c.emitLoadLocal(t.Name)
ast.Walk(c, n.Rhs[0])
c.convertToken(n.Tok)
l := c.fctx.loadLocal(t.Name)
c.emitStoreLocal(l)
default:
ast.Walk(c, n.Rhs[0])
l := c.fctx.loadLocal(t.Name)
c.emitStoreLocal(l)
}
case *ast.SelectorExpr:
switch expr := t.X.(type) {
case *ast.Ident:
ast.Walk(c, n.Rhs[i])
c.emitLoadLocal(expr.Name) // load the struct
c.emitStoreStructField(expr.Name, t.Sel.Name) // store the field
default:
log.Fatal("nested selector assigns not supported yet")
}
}
}
return nil
case *ast.ReturnStmt:
if len(n.Results) > 1 {
log.Fatal("multiple returns not supported.")
}
emitOpcode(c.prog, vm.Ojmp)
emitOpcode(c.prog, vm.Opcode(0x03))
emitOpcode(c.prog, vm.Opush0)
if len(n.Results) > 0 {
ast.Walk(c, n.Results[0])
}
emitOpcode(c.prog, vm.Onop)
emitOpcode(c.prog, vm.Ofromaltstack)
emitOpcode(c.prog, vm.Odrop)
emitOpcode(c.prog, vm.Oret)
return nil
case *ast.IfStmt:
lIf := c.newLabel()
lElse := c.newLabel()
if n.Cond != nil {
ast.Walk(c, n.Cond)
emitJmp(c.prog, vm.Ojmpifnot, int16(lElse))
}
c.setLabel(lIf)
ast.Walk(c, n.Body)
if n.Else != nil {
// TODO: handle else statements.
// emitJmp(c.prog, vm.Ojmp, int16(lEnd))
}
c.setLabel(lElse)
if n.Else != nil {
ast.Walk(c, n.Else)
}
return nil
case *ast.BasicLit:
c.emitLoadConst(c.getTypeInfo(n))
return nil
case *ast.Ident:
if isIdentBool(n) {
c.emitLoadConst(makeBoolFromIdent(n, c.typeInfo))
} else {
c.emitLoadLocal(n.Name)
}
return nil
case *ast.CompositeLit:
var typ types.Type
switch t := n.Type.(type) {
case *ast.Ident:
typ = c.typeInfo.ObjectOf(t).Type().Underlying()
case *ast.SelectorExpr:
typ = c.typeInfo.ObjectOf(t.Sel).Type().Underlying()
default:
ln := len(n.Elts)
for i := ln - 1; i >= 0; i-- {
c.emitLoadConst(c.getTypeInfo(n.Elts[i]))
}
emitInt(c.prog, int64(ln))
emitOpcode(c.prog, vm.Opack)
return nil
}
switch typ.(type) {
case *types.Struct:
c.convertStruct(n)
}
return nil
case *ast.BinaryExpr:
switch n.Op {
case token.LAND:
ast.Walk(c, n.X)
emitJmp(c.prog, vm.Ojmpifnot, int16(len(c.l)-1))
ast.Walk(c, n.Y)
return nil
case token.LOR:
ast.Walk(c, n.X)
emitJmp(c.prog, vm.Ojmpif, int16(len(c.l)-2))
ast.Walk(c, n.Y)
return nil
default:
// The AST package will try to resolve all basic literals for us.
// If the typeinfo.Value is not nil we know that the expr is resolved
// and needs no further action. e.g. x := 2 + 2 + 2 will be resolved to 6.
if tinfo := c.getTypeInfo(n); tinfo.Value != nil {
c.emitLoadConst(tinfo)
return c
}
ast.Walk(c, n.X)
ast.Walk(c, n.Y)
c.convertToken(n.Op)
return nil
}
case *ast.CallExpr:
var (
f *funcScope
ok bool
numArgs = len(n.Args)
)
switch fun := n.Fun.(type) {
case *ast.Ident:
f, ok = c.funcs[fun.Name]
if !ok {
log.Fatalf("could not resolve function %s", fun.Name)
}
case *ast.SelectorExpr:
// If this is a method call we need to walk the AST to load the struct locally.
// Otherwise this is a function call from a imported package and we can call it
// directly.
if c.typeInfo.Selections[fun] != nil {
ast.Walk(c, fun.X)
// Dont forget to add 1 extra argument when its a method.
numArgs++
}
f, ok = c.funcs[fun.Sel.Name]
if !ok {
log.Fatalf("could not resolve function %s", fun.Sel.Name)
}
}
// Handle the arguments
for _, arg := range n.Args {
ast.Walk(c, arg)
}
if numArgs == 2 {
emitOpcode(c.prog, vm.Oswap)
}
if numArgs == 3 {
emitInt(c.prog, 2)
emitOpcode(c.prog, vm.Oxswap)
}
// c# compiler adds a NOP (0x61) before every function call. Dont think its relevant
// and we could easily removed it, but to be consistent with the original compiler I
// will put them in. ^^
emitOpcode(c.prog, vm.Onop)
if isSyscall(f.name) {
c.convertSyscall(f.name)
} else {
emitCall(c.prog, vm.Ocall, int16(f.label))
}
// If we are not assigning this function to a variable we need to drop
// the top stack item. It's not a void but you get the point \o/.
if _, ok := c.fctx.voidCalls[n]; ok && !isNoRetSyscall(f.name) {
emitOpcode(c.prog, vm.Odrop)
}
return nil
case *ast.SelectorExpr:
switch t := n.X.(type) {
case *ast.Ident:
c.emitLoadLocal(t.Name) // load the struct
c.emitLoadStructField(t.Name, n.Sel.Name) // load the field
default:
log.Fatal("nested selectors not supported yet")
}
return nil
}
return c
}
func (c *codegen) convertSyscall(name string) {
api, ok := vm.Syscalls[name]
if !ok {
log.Fatalf("unknown VM syscall api: %s", name)
}
emitSyscall(c.prog, api)
emitOpcode(c.prog, vm.Onop)
}
func (c *codegen) convertStruct(lit *ast.CompositeLit) {
// Create a new structScope to initialize and store
// the positions of its variables.
t, ok := c.typeInfo.TypeOf(lit).Underlying().(*types.Struct)
if !ok {
log.Fatalf("the given literal is not of type struct: %v", lit)
}
strct := c.fctx.newStruct(t)
emitOpcode(c.prog, vm.Onop)
emitInt(c.prog, int64(strct.t.NumFields()))
emitOpcode(c.prog, vm.Onewstruct)
emitOpcode(c.prog, vm.Otoaltstack)
// 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.t.NumFields(); i++ {
sField := strct.t.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 := strct.loadField(fieldName)
c.emitStoreLocal(pos)
fieldAdded = true
break
}
}
if fieldAdded {
continue
}
c.emitLoadConst(strct.typeAndValues[sField.Name()])
c.emitStoreLocal(i)
}
emitOpcode(c.prog, vm.Ofromaltstack)
}
func (c *codegen) convertToken(tok token.Token) {
switch tok {
case token.ADD_ASSIGN:
emitOpcode(c.prog, vm.Oadd)
case token.SUB_ASSIGN:
emitOpcode(c.prog, vm.Osub)
case token.MUL_ASSIGN:
emitOpcode(c.prog, vm.Omul)
case token.QUO_ASSIGN:
emitOpcode(c.prog, vm.Odiv)
case token.ADD:
emitOpcode(c.prog, vm.Oadd)
case token.SUB:
emitOpcode(c.prog, vm.Osub)
case token.MUL:
emitOpcode(c.prog, vm.Omul)
case token.QUO:
emitOpcode(c.prog, vm.Odiv)
case token.LSS:
emitOpcode(c.prog, vm.Olt)
case token.LEQ:
emitOpcode(c.prog, vm.Olte)
case token.GTR:
emitOpcode(c.prog, vm.Ogt)
case token.GEQ:
emitOpcode(c.prog, vm.Ogte)
case token.EQL, token.NEQ:
emitOpcode(c.prog, vm.Onumequal)
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
}
// TODO: Don't know if we really use this. Check if it can be deleted.
// If it's used once or twice, also remove this functions and
// call .Types direcly. e.g. c.typeInfo.Types[expr]
func (c *codegen) getTypeInfo(expr ast.Expr) types.TypeAndValue {
return c.typeInfo.Types[expr]
}
func makeBoolFromIdent(ident *ast.Ident, tinfo *types.Info) types.TypeAndValue {
var b bool
if ident.Name == "true" {
b = true
} else if ident.Name == "false" {
b = false
} else {
log.Fatalf("givent identifier cannot be converted to a boolean => %s", ident.Name)
}
return types.TypeAndValue{
Type: tinfo.ObjectOf(ident).Type(),
Value: constant.MakeBool(b),
}
}
func isIdentBool(ident *ast.Ident) bool {
return ident.Name == "true" || ident.Name == "false"
}
// CodeGen is the function that compiles the program to bytecode.
func CodeGen(f *ast.File, tInfo *types.Info, imports map[string]*archive) (*bytes.Buffer, error) {
c := &codegen{
prog: new(bytes.Buffer),
l: []int{},
funcs: map[string]*funcScope{},
typeInfo: tInfo,
}
var main *ast.FuncDecl
ast.Inspect(f, func(n ast.Node) bool {
switch t := n.(type) {
case *ast.FuncDecl:
if t.Name.Name == mainIdent {
main = t
return false
}
}
return true
})
if main == nil {
log.Fatal("could not find func main. did you forgot to declare it?")
}
// Bring all imported functions into scope
for _, arch := range imports {
c.resolveFuncDecls(arch.f)
}
c.resolveFuncDecls(f)
c.convertFuncDecl(main)
for _, decl := range f.Decls {
switch n := decl.(type) {
case *ast.FuncDecl:
if n.Name.Name != mainIdent {
c.convertFuncDecl(n)
}
}
}
// Generate code for the imported packages.
for _, arch := range imports {
c.typeInfo = arch.typeInfo
for _, decl := range arch.f.Decls {
switch n := decl.(type) {
case *ast.FuncDecl:
if n.Name.Name != mainIdent {
c.convertFuncDecl(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.Opcode(op) {
case vm.Ojmpifnot, vm.Ojmpif, vm.Ocall:
index := binary.LittleEndian.Uint16(b[j : j+2])
if int(index) > len(c.l) {
continue
}
offset := uint16(c.l[index] - i)
if offset < 0 {
log.Fatalf("new offset is negative, table list %v", c.l)
}
binary.LittleEndian.PutUint16(b[j:j+2], offset)
}
}
}
func isSyscall(name string) bool {
_, ok := vm.Syscalls[name]
return ok
}
var noRetSyscalls = []string{
"Notify", "Log", "Put", "Register", "Delete",
"SetVotes", "ContractDestroy", "MerkleRoot", "Hash",
"PrevHash", "GetHeader",
}
// isNoRetSyscall checks if the syscall has a return value.
func isNoRetSyscall(name string) bool {
for _, s := range noRetSyscalls {
if s == name {
return true
}
}
return false
}