| // Copyright 2013 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package oracle contains the implementation of the oracle tool whose |
| // command-line is provided by code.google.com/p/go.tools/cmd/oracle. |
| // |
| // http://golang.org/s/oracle-design |
| // http://golang.org/s/oracle-user-manual |
| // |
| package oracle |
| |
| // This file defines oracle.Query, the entry point for the oracle tool. |
| // The actual executable is defined in cmd/oracle. |
| |
| // TODO(adonovan): new query: show all statements that may update the |
| // selected lvalue (local, global, field, etc). |
| |
| import ( |
| "bytes" |
| "fmt" |
| "go/ast" |
| "go/build" |
| "go/printer" |
| "go/token" |
| "io" |
| "os" |
| "path/filepath" |
| "strconv" |
| "strings" |
| "time" |
| |
| "code.google.com/p/go.tools/go/types" |
| "code.google.com/p/go.tools/importer" |
| "code.google.com/p/go.tools/oracle/serial" |
| "code.google.com/p/go.tools/pointer" |
| "code.google.com/p/go.tools/ssa" |
| ) |
| |
| // An Oracle holds the program state required for one or more queries. |
| type Oracle struct { |
| out io.Writer // standard output |
| prog *ssa.Program // the SSA program [only populated if need&SSA] |
| config pointer.Config // pointer analysis configuration [TODO rename ptaConfig] |
| |
| // need&AllTypeInfo |
| typeInfo map[*types.Package]*importer.PackageInfo // type info for all ASTs in the program |
| |
| timers map[string]time.Duration // phase timing information |
| } |
| |
| // A set of bits indicating the analytical requirements of each mode. |
| // |
| // Typed ASTs for the whole program are always constructed |
| // transiently; they are retained only for the queried package unless |
| // needAllTypeInfo is set. |
| const ( |
| needPos = 1 << iota // needs a position |
| needExactPos // needs an exact AST selection; implies needPos |
| needAllTypeInfo // needs to retain type info for all ASTs in the program |
| needSSA // needs ssa.Packages for whole program |
| needSSADebug // needs debug info for ssa.Packages |
| needPTA = needSSA // needs pointer analysis |
| needAll = -1 // needs everything (e.g. a sequence of queries) |
| ) |
| |
| type modeInfo struct { |
| name string |
| needs int |
| impl func(*Oracle, *QueryPos) (queryResult, error) |
| } |
| |
| var modes = []*modeInfo{ |
| {"callees", needPTA | needExactPos, callees}, |
| {"callers", needPTA | needPos, callers}, |
| {"callgraph", needPTA, callgraph}, |
| {"callstack", needPTA | needPos, callstack}, |
| {"describe", needPTA | needSSADebug | needExactPos, describe}, |
| {"freevars", needPos, freevars}, |
| {"implements", needPos, implements}, |
| {"peers", needPTA | needSSADebug | needPos, peers}, |
| {"referrers", needAllTypeInfo | needPos, referrers}, |
| } |
| |
| func findMode(mode string) *modeInfo { |
| for _, m := range modes { |
| if m.name == mode { |
| return m |
| } |
| } |
| return nil |
| } |
| |
| type printfFunc func(pos interface{}, format string, args ...interface{}) |
| |
| // queryResult is the interface of each query-specific result type. |
| type queryResult interface { |
| toSerial(res *serial.Result, fset *token.FileSet) |
| display(printf printfFunc) |
| } |
| |
| // A QueryPos represents the position provided as input to a query: |
| // a textual extent in the program's source code, the AST node it |
| // corresponds to, and the package to which it belongs. |
| // Instances are created by ParseQueryPos. |
| // |
| type QueryPos struct { |
| start, end token.Pos // source extent of query |
| info *importer.PackageInfo // type info for the queried package |
| path []ast.Node // AST path from query node to root of ast.File |
| } |
| |
| // A Result encapsulates the result of an oracle.Query. |
| type Result struct { |
| fset *token.FileSet |
| // fprintf is a closure over the oracle's fileset and start/end position. |
| fprintf func(w io.Writer, pos interface{}, format string, args ...interface{}) |
| q queryResult // the query-specific result |
| mode string // query mode |
| warnings []pointer.Warning // pointer analysis warnings |
| } |
| |
| // Serial returns an instance of serial.Result, which implements the |
| // {xml,json}.Marshaler interfaces so that query results can be |
| // serialized as JSON or XML. |
| // |
| func (res *Result) Serial() *serial.Result { |
| resj := &serial.Result{Mode: res.mode} |
| res.q.toSerial(resj, res.fset) |
| for _, w := range res.warnings { |
| resj.Warnings = append(resj.Warnings, serial.PTAWarning{ |
| Pos: res.fset.Position(w.Pos).String(), |
| Message: w.Message, |
| }) |
| } |
| return resj |
| } |
| |
| // Query runs a single oracle query. |
| // |
| // args specify the main package in importer.CreatePackageFromArgs syntax. |
| // mode is the query mode ("callers", etc). |
| // ptalog is the (optional) pointer-analysis log file. |
| // buildContext is the go/build configuration for locating packages. |
| // reflection determines whether to model reflection soundly (currently slow). |
| // |
| // Clients that intend to perform multiple queries against the same |
| // analysis scope should use this pattern instead: |
| // |
| // imp := importer.New(&importer.Config{Build: buildContext}) |
| // o, err := oracle.New(imp, args, nil) |
| // if err != nil { ... } |
| // for ... { |
| // qpos, err := oracle.ParseQueryPos(imp, pos, needExact) |
| // if err != nil { ... } |
| // |
| // res, err := o.Query(mode, qpos) |
| // if err != nil { ... } |
| // |
| // // use res |
| // } |
| // |
| // TODO(adonovan): the ideal 'needsExact' parameter for ParseQueryPos |
| // depends on the query mode; how should we expose this? |
| // |
| func Query(args []string, mode, pos string, ptalog io.Writer, buildContext *build.Context, reflection bool) (*Result, error) { |
| minfo := findMode(mode) |
| if minfo == nil { |
| return nil, fmt.Errorf("invalid mode type: %q", mode) |
| } |
| |
| imp := importer.New(&importer.Config{Build: buildContext}) |
| o, err := New(imp, args, ptalog, reflection) |
| if err != nil { |
| return nil, err |
| } |
| |
| // Phase timing diagnostics. |
| // TODO(adonovan): needs more work. |
| // if false { |
| // defer func() { |
| // fmt.Println() |
| // for name, duration := range o.timers { |
| // fmt.Printf("# %-30s %s\n", name, duration) |
| // } |
| // }() |
| // } |
| |
| var qpos *QueryPos |
| if minfo.needs&(needPos|needExactPos) != 0 { |
| var err error |
| qpos, err = ParseQueryPos(imp, pos, minfo.needs&needExactPos != 0) |
| if err != nil { |
| return nil, err |
| } |
| } |
| |
| // SSA is built and we have the QueryPos. |
| // Release the other ASTs and type info to the GC. |
| imp = nil |
| |
| return o.query(minfo, qpos) |
| } |
| |
| // New constructs a new Oracle that can be used for a sequence of queries. |
| // |
| // imp will be used to load source code for imported packages. |
| // It must not yet have loaded any packages. |
| // |
| // args specify the main package in importer.CreatePackageFromArgs syntax. |
| // |
| // ptalog is the (optional) pointer-analysis log file. |
| // reflection determines whether to model reflection soundly (currently slow). |
| // |
| func New(imp *importer.Importer, args []string, ptalog io.Writer, reflection bool) (*Oracle, error) { |
| return newOracle(imp, args, ptalog, needAll, reflection) |
| } |
| |
| func newOracle(imp *importer.Importer, args []string, ptalog io.Writer, needs int, reflection bool) (*Oracle, error) { |
| o := &Oracle{ |
| prog: ssa.NewProgram(imp.Fset, 0), |
| timers: make(map[string]time.Duration), |
| } |
| o.config.Log = ptalog |
| o.config.Reflection = reflection |
| |
| // Load/parse/type-check program from args. |
| start := time.Now() |
| initialPkgInfos, args, err := imp.LoadInitialPackages(args) |
| if err != nil { |
| return nil, err // I/O or parser error |
| } |
| if len(args) > 0 { |
| return nil, fmt.Errorf("surplus arguments: %q", args) |
| } |
| o.timers["load/parse/type"] = time.Since(start) |
| |
| // Retain type info for all ASTs in the program. |
| if needs&needAllTypeInfo != 0 { |
| m := make(map[*types.Package]*importer.PackageInfo) |
| for _, p := range imp.AllPackages() { |
| m[p.Pkg] = p |
| } |
| o.typeInfo = m |
| } |
| |
| // Create SSA package for the initial package and its dependencies. |
| if needs&needSSA != 0 { |
| start = time.Now() |
| |
| // Create SSA packages. |
| if err := o.prog.CreatePackages(imp); err != nil { |
| return nil, err |
| } |
| |
| // Initial packages (specified on command line) |
| for _, info := range initialPkgInfos { |
| initialPkg := o.prog.Package(info.Pkg) |
| |
| // Add package to the pointer analysis scope. |
| if initialPkg.Func("main") == nil { |
| // TODO(adonovan): to simulate 'go test' more faithfully, we |
| // should build a single synthetic testmain package, |
| // not synthetic main functions to many packages. |
| if initialPkg.CreateTestMainFunction() == nil { |
| return nil, fmt.Errorf("analysis scope has no main() entry points") |
| } |
| } |
| o.config.Mains = append(o.config.Mains, initialPkg) |
| } |
| |
| if needs&needSSADebug != 0 { |
| for _, pkg := range o.prog.AllPackages() { |
| pkg.SetDebugMode(true) |
| } |
| } |
| |
| o.timers["SSA-create"] = time.Since(start) |
| } |
| |
| return o, nil |
| } |
| |
| // Query runs the query of the specified mode and selection. |
| func (o *Oracle) Query(mode string, qpos *QueryPos) (*Result, error) { |
| minfo := findMode(mode) |
| if minfo == nil { |
| return nil, fmt.Errorf("invalid mode type: %q", mode) |
| } |
| return o.query(minfo, qpos) |
| } |
| |
| func (o *Oracle) query(minfo *modeInfo, qpos *QueryPos) (*Result, error) { |
| res := &Result{ |
| mode: minfo.name, |
| fset: o.prog.Fset, |
| fprintf: o.fprintf, // captures o.prog, o.{start,end}Pos for later printing |
| } |
| var err error |
| res.q, err = minfo.impl(o, qpos) |
| if err != nil { |
| return nil, err |
| } |
| return res, nil |
| } |
| |
| // ParseQueryPos parses the source query position pos. |
| // If needExact, it must identify a single AST subtree. |
| // |
| func ParseQueryPos(imp *importer.Importer, pos string, needExact bool) (*QueryPos, error) { |
| start, end, err := parseQueryPos(imp.Fset, pos) |
| if err != nil { |
| return nil, err |
| } |
| info, path, exact := imp.PathEnclosingInterval(start, end) |
| if path == nil { |
| return nil, fmt.Errorf("no syntax here") |
| } |
| if needExact && !exact { |
| return nil, fmt.Errorf("ambiguous selection within %s", importer.NodeDescription(path[0])) |
| } |
| return &QueryPos{start, end, info, path}, nil |
| } |
| |
| // WriteTo writes the oracle query result res to out in a compiler diagnostic format. |
| func (res *Result) WriteTo(out io.Writer) { |
| printf := func(pos interface{}, format string, args ...interface{}) { |
| res.fprintf(out, pos, format, args...) |
| } |
| res.q.display(printf) |
| |
| // Print warnings after the main output. |
| if res.warnings != nil { |
| fmt.Fprintln(out, "\nPointer analysis warnings:") |
| for _, w := range res.warnings { |
| printf(w.Pos, "warning: "+w.Message) |
| } |
| } |
| } |
| |
| // ---------- Utilities ---------- |
| |
| // buildSSA constructs the SSA representation of Go-source function bodies. |
| // Not needed in simpler modes, e.g. freevars. |
| // |
| func buildSSA(o *Oracle) { |
| start := time.Now() |
| o.prog.BuildAll() |
| o.timers["SSA-build"] = time.Since(start) |
| } |
| |
| // ptrAnalysis runs the pointer analysis and returns its result. |
| func ptrAnalysis(o *Oracle) *pointer.Result { |
| start := time.Now() |
| result := pointer.Analyze(&o.config) |
| o.timers["pointer analysis"] = time.Since(start) |
| return result |
| } |
| |
| // parseOctothorpDecimal returns the numeric value if s matches "#%d", |
| // otherwise -1. |
| func parseOctothorpDecimal(s string) int { |
| if s != "" && s[0] == '#' { |
| if s, err := strconv.ParseInt(s[1:], 10, 32); err == nil { |
| return int(s) |
| } |
| } |
| return -1 |
| } |
| |
| // parseQueryPos parses a string of the form "file:pos" or |
| // file:start,end" where pos, start, end match #%d and represent byte |
| // offsets, and returns the extent to which it refers. |
| // |
| // (Numbers without a '#' prefix are reserved for future use, |
| // e.g. to indicate line/column positions.) |
| // |
| func parseQueryPos(fset *token.FileSet, queryPos string) (start, end token.Pos, err error) { |
| if queryPos == "" { |
| err = fmt.Errorf("no source position specified (-pos flag)") |
| return |
| } |
| |
| colon := strings.LastIndex(queryPos, ":") |
| if colon < 0 { |
| err = fmt.Errorf("invalid source position -pos=%q", queryPos) |
| return |
| } |
| filename, offset := queryPos[:colon], queryPos[colon+1:] |
| startOffset := -1 |
| endOffset := -1 |
| if hyphen := strings.Index(offset, ","); hyphen < 0 { |
| // e.g. "foo.go:#123" |
| startOffset = parseOctothorpDecimal(offset) |
| endOffset = startOffset |
| } else { |
| // e.g. "foo.go:#123,#456" |
| startOffset = parseOctothorpDecimal(offset[:hyphen]) |
| endOffset = parseOctothorpDecimal(offset[hyphen+1:]) |
| } |
| if startOffset < 0 || endOffset < 0 { |
| err = fmt.Errorf("invalid -pos offset %q", offset) |
| return |
| } |
| |
| var file *token.File |
| fset.Iterate(func(f *token.File) bool { |
| if sameFile(filename, f.Name()) { |
| // (f.Name() is absolute) |
| file = f |
| return false // done |
| } |
| return true // continue |
| }) |
| if file == nil { |
| err = fmt.Errorf("couldn't find file containing position -pos=%q", queryPos) |
| return |
| } |
| |
| // Range check [start..end], inclusive of both end-points. |
| |
| if 0 <= startOffset && startOffset <= file.Size() { |
| start = file.Pos(int(startOffset)) |
| } else { |
| err = fmt.Errorf("start position is beyond end of file -pos=%q", queryPos) |
| return |
| } |
| |
| if 0 <= endOffset && endOffset <= file.Size() { |
| end = file.Pos(int(endOffset)) |
| } else { |
| err = fmt.Errorf("end position is beyond end of file -pos=%q", queryPos) |
| return |
| } |
| |
| return |
| } |
| |
| // sameFile returns true if x and y have the same basename and denote |
| // the same file. |
| // |
| func sameFile(x, y string) bool { |
| if filepath.Base(x) == filepath.Base(y) { // (optimisation) |
| if xi, err := os.Stat(x); err == nil { |
| if yi, err := os.Stat(y); err == nil { |
| return os.SameFile(xi, yi) |
| } |
| } |
| } |
| return false |
| } |
| |
| // unparen returns e with any enclosing parentheses stripped. |
| func unparen(e ast.Expr) ast.Expr { |
| for { |
| p, ok := e.(*ast.ParenExpr) |
| if !ok { |
| break |
| } |
| e = p.X |
| } |
| return e |
| } |
| |
| // deref returns a pointer's element type; otherwise it returns typ. |
| func deref(typ types.Type) types.Type { |
| if p, ok := typ.Underlying().(*types.Pointer); ok { |
| return p.Elem() |
| } |
| return typ |
| } |
| |
| // fprintf prints to w a message of the form "location: message\n" |
| // where location is derived from pos. |
| // |
| // pos must be one of: |
| // - a token.Pos, denoting a position |
| // - an ast.Node, denoting an interval |
| // - anything with a Pos() method: |
| // ssa.Member, ssa.Value, ssa.Instruction, types.Object, pointer.Label, etc. |
| // - a QueryPos, denoting the extent of the user's query. |
| // - nil, meaning no position at all. |
| // |
| // The output format is is compatible with the 'gnu' |
| // compilation-error-regexp in Emacs' compilation mode. |
| // TODO(adonovan): support other editors. |
| // |
| func (o *Oracle) fprintf(w io.Writer, pos interface{}, format string, args ...interface{}) { |
| var start, end token.Pos |
| switch pos := pos.(type) { |
| case ast.Node: |
| start = pos.Pos() |
| end = pos.End() |
| case token.Pos: |
| start = pos |
| end = start |
| case interface { |
| Pos() token.Pos |
| }: |
| start = pos.Pos() |
| end = start |
| case *QueryPos: |
| start = pos.start |
| end = pos.end |
| case nil: |
| // no-op |
| default: |
| panic(fmt.Sprintf("invalid pos: %T", pos)) |
| } |
| |
| if sp := o.prog.Fset.Position(start); start == end { |
| // (prints "-: " for token.NoPos) |
| fmt.Fprintf(w, "%s: ", sp) |
| } else { |
| ep := o.prog.Fset.Position(end) |
| // The -1 below is a concession to Emacs's broken use of |
| // inclusive (not half-open) intervals. |
| // Other editors may not want it. |
| // TODO(adonovan): add an -editor=vim|emacs|acme|auto |
| // flag; auto uses EMACS=t / VIM=... / etc env vars. |
| fmt.Fprintf(w, "%s:%d.%d-%d.%d: ", |
| sp.Filename, sp.Line, sp.Column, ep.Line, ep.Column-1) |
| } |
| fmt.Fprintf(w, format, args...) |
| io.WriteString(w, "\n") |
| } |
| |
| // printNode returns the pretty-printed syntax of n. |
| func (o *Oracle) printNode(n ast.Node) string { |
| var buf bytes.Buffer |
| printer.Fprint(&buf, o.prog.Fset, n) |
| return buf.String() |
| } |