neo-go/pkg/compiler/analysis.go
Evgenii Stratonikov bf6aa02dcf compiler: set default values for complex struct fields
Set default value also for complex (struct, map) types.
Note: because VM does not distinguish empty array and nil array,
comparison 'a == nil' can't be handled properly without substantial
effort. This will be fixed in NEO3.
2020-06-11 17:40:02 +03:00

247 lines
5.5 KiB
Go

package compiler
import (
"fmt"
"go/ast"
"go/constant"
"go/types"
"golang.org/x/tools/go/loader"
)
var (
// Go language builtin functions and custom builtin utility functions.
builtinFuncs = []string{
"len", "append", "SHA256",
"SHA1", "Hash256", "Hash160",
"VerifySignature", "AppCall",
"FromAddress", "Equals",
"panic", "DynAppCall",
"delete", "Remove",
}
)
// typeAndValueForField returns a zero initialized typeAndValue for the given type.Var.
func typeAndValueForField(fld *types.Var) (types.TypeAndValue, error) {
switch t := fld.Type().(type) {
case *types.Basic:
switch t.Kind() {
case types.Int:
return types.TypeAndValue{
Type: t,
Value: constant.MakeInt64(0),
}, nil
case types.String:
return types.TypeAndValue{
Type: t,
Value: constant.MakeString(""),
}, nil
case types.Bool, types.UntypedBool:
return types.TypeAndValue{
Type: t,
Value: constant.MakeBool(false),
}, nil
default:
return types.TypeAndValue{}, fmt.Errorf("could not initialize struct field %s to zero, type: %s", fld.Name(), t)
}
default:
return types.TypeAndValue{Type: t}, nil
}
}
// countGlobals counts the global variables in the program to add
// them with the stack size of the function.
func countGlobals(f ast.Node) (i int64) {
ast.Inspect(f, func(node ast.Node) bool {
switch node.(type) {
// Skip all function declarations.
case *ast.FuncDecl:
return false
// After skipping all funcDecls we are sure that each value spec
// is a global declared variable or constant.
case *ast.ValueSpec:
i++
}
return true
})
return
}
// isIdentBool looks if the given ident is a boolean.
func isIdentBool(ident *ast.Ident) bool {
return ident.Name == "true" || ident.Name == "false"
}
// isExprNil looks if the given expression is a `nil`.
func isExprNil(e ast.Expr) bool {
v, ok := e.(*ast.Ident)
return ok && v.Name == "nil"
}
// makeBoolFromIdent creates a bool type from an *ast.Ident.
func makeBoolFromIdent(ident *ast.Ident, tinfo *types.Info) (types.TypeAndValue, error) {
var b bool
switch ident.Name {
case "true":
b = true
case "false":
b = false
default:
return types.TypeAndValue{}, fmt.Errorf("givent identifier cannot be converted to a boolean => %s", ident.Name)
}
return types.TypeAndValue{
Type: tinfo.ObjectOf(ident).Type(),
Value: constant.MakeBool(b),
}, nil
}
// resolveEntryPoint returns the function declaration of the entrypoint and the corresponding file.
func resolveEntryPoint(entry string, pkg *loader.PackageInfo) (*ast.FuncDecl, *ast.File) {
var (
main *ast.FuncDecl
file *ast.File
)
for _, f := range pkg.Files {
ast.Inspect(f, func(n ast.Node) bool {
switch t := n.(type) {
case *ast.FuncDecl:
if t.Name.Name == entry {
main = t
file = f
return false
}
}
return true
})
}
return main, file
}
// indexOfStruct returns the index of the given field inside that struct.
// If the struct does not contain that field it will return -1.
func indexOfStruct(strct *types.Struct, fldName string) int {
for i := 0; i < strct.NumFields(); i++ {
if strct.Field(i).Name() == fldName {
return i
}
}
return -1
}
type funcUsage map[string]bool
func (f funcUsage) funcUsed(name string) bool {
_, ok := f[name]
return ok
}
// lastStmtIsReturn checks if last statement of the declaration was return statement..
func lastStmtIsReturn(decl *ast.FuncDecl) (b bool) {
if l := len(decl.Body.List); l != 0 {
_, ok := decl.Body.List[l-1].(*ast.ReturnStmt)
return ok
}
return false
}
func analyzeFuncUsage(pkgs map[*types.Package]*loader.PackageInfo) funcUsage {
usage := funcUsage{}
for _, pkg := range pkgs {
for _, f := range pkg.Files {
ast.Inspect(f, func(node ast.Node) bool {
switch n := node.(type) {
case *ast.CallExpr:
switch t := n.Fun.(type) {
case *ast.Ident:
usage[t.Name] = true
case *ast.SelectorExpr:
usage[t.Sel.Name] = true
}
}
return true
})
}
}
return usage
}
func isBuiltin(expr ast.Expr) bool {
var name string
switch t := expr.(type) {
case *ast.Ident:
name = t.Name
case *ast.SelectorExpr:
name = t.Sel.Name
default:
return false
}
for _, n := range builtinFuncs {
if name == n {
return true
}
}
return false
}
func (c *codegen) isCompoundArrayType(t ast.Expr) bool {
switch s := t.(type) {
case *ast.ArrayType:
return true
case *ast.Ident:
arr, ok := c.typeInfo.Types[s].Type.Underlying().(*types.Slice)
return ok && !isByte(arr.Elem())
}
return false
}
func isByte(t types.Type) bool {
e, ok := t.(*types.Basic)
return ok && e.Kind() == types.Byte
}
func (c *codegen) isStructType(t ast.Expr) (int, bool) {
switch s := t.(type) {
case *ast.StructType:
return s.Fields.NumFields(), true
case *ast.Ident:
st, ok := c.typeInfo.Types[s].Type.Underlying().(*types.Struct)
if ok {
return st.NumFields(), true
}
}
return 0, false
}
func isByteArray(lit *ast.CompositeLit, tInfo *types.Info) bool {
if len(lit.Elts) == 0 {
if typ, ok := lit.Type.(*ast.ArrayType); ok {
if name, ok := typ.Elt.(*ast.Ident); ok {
return name.Name == "byte" || name.Name == "uint8"
}
}
return false
}
typ := tInfo.Types[lit.Elts[0]].Type.Underlying()
return isByte(typ)
}
func isSyscall(fun *funcScope) bool {
if fun.selector == nil {
return false
}
_, ok := syscalls[fun.selector.Name][fun.name]
return ok
}
func isByteArrayType(t types.Type) bool {
return t.String() == "[]byte"
}
func isStringType(t types.Type) bool {
return t.String() == "string"
}