package compiler import ( "go/ast" "go/constant" "go/types" "log" "golang.org/x/tools/go/loader" ) var ( // Go language builtin functions and custom builtin utility functions. builtinFuncs = []string{ "len", "append", "SHA256", "SHA1", "Hash256", "Hash160", "FromAddress", } // 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 { 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 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" }