package compiler import ( "errors" "go/ast" "go/token" "go/types" "strings" "github.com/nspcc-dev/neo-go/pkg/vm/emit" "github.com/nspcc-dev/neo-go/pkg/vm/opcode" "golang.org/x/tools/go/packages" ) var ( // Go language builtin functions. goBuiltins = []string{"len", "append", "panic", "make", "copy", "recover", "delete"} // Custom builtin utility functions. customBuiltins = []string{ "FromAddress", } ) // newGlobal creates a new global variable. func (c *codegen) newGlobal(pkg string, name string) { name = c.getIdentName(pkg, name) c.globals[name] = len(c.globals) } // getIdentName returns a fully-qualified name for a variable. func (c *codegen) getIdentName(pkg string, name string) string { if fullName, ok := c.importMap[pkg]; ok { pkg = fullName } return pkg + "." + name } // traverseGlobals visits and initializes global variables. // It returns `true` if contract has `_deploy` function. func (c *codegen) traverseGlobals() bool { var hasDefer bool var n, nConst int var hasDeploy bool c.ForEachFile(func(f *ast.File, pkg *types.Package) { nv, nc := countGlobals(f) n += nv nConst += nc if !hasDeploy || !hasDefer { ast.Inspect(f, func(node ast.Node) bool { switch n := node.(type) { case *ast.FuncDecl: hasDeploy = hasDeploy || isDeployFunc(n) case *ast.DeferStmt: hasDefer = true return false } return true }) } }) if hasDefer { n++ } if n > 255 { c.prog.BinWriter.Err = errors.New("too many global variables") return hasDeploy } if n != 0 { emit.Instruction(c.prog.BinWriter, opcode.INITSSLOT, []byte{byte(n)}) } initOffset := c.prog.Len() emit.Instruction(c.prog.BinWriter, opcode.INITSLOT, []byte{0, 0}) lastCnt, maxCnt := -1, -1 c.ForEachPackage(func(pkg *packages.Package) { if n+nConst > 0 { for _, f := range pkg.Syntax { c.fillImportMap(f, pkg) c.convertGlobals(f, pkg.Types) } } for _, f := range pkg.Syntax { c.fillImportMap(f, pkg) var currMax int lastCnt, currMax = c.convertInitFuncs(f, pkg.Types, lastCnt) if currMax > maxCnt { maxCnt = currMax } } // because we reuse `convertFuncDecl` for init funcs, // we need to clear scope, so that global variables // encountered after will be recognized as globals. c.scope = nil }) if c.globalInlineCount > maxCnt { maxCnt = c.globalInlineCount } // Here we remove `INITSLOT` if no code was emitted for `init` function. // Note that the `INITSSLOT` must stay in place. hasNoInit := initOffset+3 == c.prog.Len() if hasNoInit { buf := c.prog.Bytes() c.prog.Reset() c.prog.WriteBytes(buf[:initOffset]) } if initOffset != 0 || !hasNoInit { // if there are some globals or `init()`. c.initEndOffset = c.prog.Len() emit.Opcodes(c.prog.BinWriter, opcode.RET) if maxCnt >= 0 { c.reverseOffsetMap[initOffset] = nameWithLocals{ name: "init", count: maxCnt, } } } // store auxiliary variables after all others. if hasDefer { c.exceptionIndex = len(c.globals) c.globals[exceptionVarName] = c.exceptionIndex } return hasDeploy } // countGlobals counts the global variables in the program to add // them with the stack size of the function. // Second returned argument contains the amount of global constants. func countGlobals(f ast.Node) (int, int) { var numVar, numConst int ast.Inspect(f, func(node ast.Node) bool { switch n := node.(type) { // Skip all function declarations if we have already encountered `defer`. 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.GenDecl: isVar := n.Tok == token.VAR if isVar || n.Tok == token.CONST { for _, s := range n.Specs { for _, id := range s.(*ast.ValueSpec).Names { if id.Name != "_" { if isVar { numVar++ } else { numConst++ } } } } } return false } return true }) return numVar, numConst } // 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" } // 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 the last statement of the declaration was return statement. func lastStmtIsReturn(body *ast.BlockStmt) (b bool) { if l := len(body.List); l != 0 { switch inner := body.List[l-1].(type) { case *ast.BlockStmt: return lastStmtIsReturn(inner) case *ast.ReturnStmt: return true default: return false } } return false } // analyzePkgOrder sets the order in which packages should be processed. // From Go spec: // A package with no imports is initialized by assigning initial values to all its package-level variables // followed by calling all init functions in the order they appear in the source, possibly in multiple files, // as presented to the compiler. If a package has imports, the imported packages are initialized before // initializing the package itself. If multiple packages import a package, the imported package // will be initialized only once. The importing of packages, by construction, guarantees // that there can be no cyclic initialization dependencies. func (c *codegen) analyzePkgOrder() { seen := make(map[string]bool) info := c.buildInfo.program[0] c.visitPkg(info, seen) } func (c *codegen) visitPkg(pkg *packages.Package, seen map[string]bool) { if seen[pkg.PkgPath] { return } for _, imp := range pkg.Types.Imports() { c.visitPkg(pkg.Imports[imp.Path()], seen) } seen[pkg.PkgPath] = true c.packages = append(c.packages, pkg.PkgPath) c.packageCache[pkg.PkgPath] = pkg } func (c *codegen) fillDocumentInfo() { fset := c.buildInfo.config.Fset fset.Iterate(func(f *token.File) bool { filePath := f.Position(f.Pos(0)).Filename c.docIndex[filePath] = len(c.documents) c.documents = append(c.documents, filePath) return true }) } // analyzeFuncUsage traverses all code and returns a map with functions // which should be present in the emitted code. // This is done using BFS starting from exported functions or // the function used in variable declarations (graph edge corresponds to // the function being called in declaration). func (c *codegen) analyzeFuncUsage() funcUsage { type declPair struct { decl *ast.FuncDecl importMap map[string]string path string } // nodeCache contains top-level function declarations . nodeCache := make(map[string]declPair) diff := funcUsage{} c.ForEachFile(func(f *ast.File, pkg *types.Package) { var pkgPath string isMain := pkg == c.mainPkg.Types if !isMain { pkgPath = pkg.Path() } ast.Inspect(f, func(node ast.Node) bool { switch n := node.(type) { case *ast.CallExpr: // functions invoked in variable declarations in imported packages // are marked as used. var name string switch t := n.Fun.(type) { case *ast.Ident: name = c.getIdentName(pkgPath, t.Name) case *ast.SelectorExpr: name, _ = c.getFuncNameFromSelector(t) default: return true } diff[name] = true case *ast.FuncDecl: name := c.getFuncNameFromDecl(pkgPath, n) // exported functions are always assumed to be used if isMain && n.Name.IsExported() || isInitFunc(n) || isDeployFunc(n) { diff[name] = true } nodeCache[name] = declPair{n, c.importMap, pkgPath} return false // will be processed in the next stage } return true }) }) usage := funcUsage{} for len(diff) != 0 { nextDiff := funcUsage{} for name := range diff { fd, ok := nodeCache[name] if !ok || usage[name] { continue } usage[name] = true pkg := c.mainPkg if fd.path != "" { pkg = c.packageCache[fd.path] } c.typeInfo = pkg.TypesInfo c.currPkg = pkg c.importMap = fd.importMap ast.Inspect(fd.decl, func(node ast.Node) bool { switch n := node.(type) { case *ast.CallExpr: switch t := n.Fun.(type) { case *ast.Ident: nextDiff[c.getIdentName(fd.path, t.Name)] = true case *ast.SelectorExpr: name, _ := c.getFuncNameFromSelector(t) nextDiff[name] = true } } return true }) } diff = nextDiff } return usage } func isGoBuiltin(name string) bool { for i := range goBuiltins { if name == goBuiltins[i] { return true } } return false } func isCustomBuiltin(f *funcScope) bool { if !isInteropPath(f.pkg.Path()) { return false } for _, n := range customBuiltins { if f.name == n { return true } } return false } func isSyscall(fun *funcScope) bool { if fun.selector == nil || fun.pkg == nil || !isInteropPath(fun.pkg.Path()) { return false } return fun.pkg.Name() == "neogointernal" && (strings.HasPrefix(fun.name, "Syscall") || strings.HasPrefix(fun.name, "Opcode") || strings.HasPrefix(fun.name, "CallWithToken")) } const interopPrefix = "github.com/nspcc-dev/neo-go/pkg/interop" func isInteropPath(s string) bool { return strings.HasPrefix(s, interopPrefix) } // canConvert returns true if type doesn't need to be converted on type assertion. func canConvert(s string) bool { if len(s) != 0 && s[0] == '*' { s = s[1:] } if isInteropPath(s) { s = s[len(interopPrefix):] return s != "/iterator.Iterator" && s != "/storage.Context" && s != "/native/ledger.Block" && s != "/native/ledger.Transaction" && s != "/native/management.Contract" && s != "/native/neo.AccountState" } return true } // canInline returns true if the function is to be inlined. // Currently, there is a static list of functions which are inlined, // this may change in future. func canInline(s string, name string) bool { if strings.HasPrefix(s, "github.com/nspcc-dev/neo-go/pkg/compiler/testdata/inline") { return true } if !isInteropPath(s) { return false } return !strings.HasPrefix(s[len(interopPrefix):], "/neogointernal") && !(strings.HasPrefix(s[len(interopPrefix):], "/util") && name == "FromAddress") }