neoneo-go/pkg/vm/compiler/analysis.go

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package compiler
import (
"go/ast"
"go/constant"
"go/types"
"log"
"golang.org/x/tools/go/loader"
)
var (
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// Go language builtin functions and custom builtin utility functions.
builtinFuncs = []string{
"len", "append", "SHA256",
"SHA1", "Hash256", "Hash160", "FromAddress",
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}
// VM system calls that have no return value.
noRetSyscalls = []string{
"Notify", "Log", "Put", "Register", "Delete",
"SetVotes", "ContractDestroy", "MerkleRoot", "Hash",
"PrevHash", "GetHeader",
}
)
// typeAndValueForField returns a zero initialized typeAndValue for the given type.Var.
func typeAndValueForField(fld *types.Var) types.TypeAndValue {
switch t := fld.Type().(type) {
case *types.Basic:
switch t.Kind() {
case types.Int:
return types.TypeAndValue{
Type: t,
Value: constant.MakeInt64(0),
}
case types.String:
return types.TypeAndValue{
Type: t,
Value: constant.MakeString(""),
}
case types.Bool, types.UntypedBool:
return types.TypeAndValue{
Type: t,
Value: constant.MakeBool(false),
}
default:
log.Fatalf("could not initialize struct field %s to zero, type: %s", fld.Name(), t)
}
}
return types.TypeAndValue{}
}
// 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"
}
// makeBoolFromIdent creates a bool type from an *ast.Ident.
func makeBoolFromIdent(ident *ast.Ident, tinfo *types.Info) types.TypeAndValue {
var b bool
switch ident.Name {
case "true":
b = true
case "false":
b = false
default:
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),
}
}
// 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 will return 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
}
// hasReturnStmt look if the given FuncDecl has a return statement.
func hasReturnStmt(decl ast.Node) (b bool) {
ast.Inspect(decl, func(node ast.Node) bool {
if _, ok := node.(*ast.ReturnStmt); ok {
b = true
return false
}
return true
})
return
}
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 {
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var name string
switch t := expr.(type) {
case *ast.Ident:
name = t.Name
case *ast.SelectorExpr:
name = t.Sel.Name
default:
return false
}
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for _, n := range builtinFuncs {
if name == n {
return true
}
}
return false
}
func isByteArray(lit *ast.CompositeLit, tInfo *types.Info) bool {
if len(lit.Elts) == 0 {
return false
}
typ := tInfo.Types[lit.Elts[0]].Type.Underlying()
switch t := typ.(type) {
case *types.Basic:
switch t.Kind() {
case types.Byte:
return true
}
}
return false
}
func isSyscall(fun *funcScope) bool {
if fun.selector == nil {
return false
}
_, ok := syscalls[fun.selector.Name][fun.name]
return ok
}
func isStringType(t types.Type) bool {
return t.String() == "string"
}