1 // Copyright 2021 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
16 "cmd/compile/internal/base"
17 "cmd/compile/internal/inline"
18 "cmd/compile/internal/ir"
19 "cmd/compile/internal/typecheck"
20 "cmd/compile/internal/types"
21 "cmd/compile/internal/types2"
25 // localPkgReader holds the package reader used for reading the local
26 // package. It exists so the unified IR linker can refer back to it
28 var localPkgReader *pkgReader
30 // unified constructs the local package's Internal Representation (IR)
31 // from its syntax tree (AST).
33 // The pipeline contains 2 steps:
35 // 1. Generate the export data "stub".
37 // 2. Generate the IR from the export data above.
39 // The package data "stub" at step (1) contains everything from the local package,
40 // but nothing that has been imported. When we're actually writing out export data
41 // to the output files (see writeNewExport), we run the "linker", which:
43 // - Updates compiler extensions data (e.g. inlining cost, escape analysis results).
45 // - Handles re-exporting any transitive dependencies.
47 // - Prunes out any unnecessary details (e.g. non-inlineable functions, because any
48 // downstream importers only care about inlinable functions).
50 // The source files are typechecked twice: once before writing the export data
51 // using types2, and again after reading the export data using gc/typecheck.
52 // The duplication of work will go away once we only use the types2 type checker,
53 // removing the gc/typecheck step. For now, it is kept because:
55 // - It reduces the engineering costs in maintaining a fork of typecheck
56 // (e.g. no need to backport fixes like CL 327651).
58 // - It makes it easier to pass toolstash -cmp.
60 // - Historically, we would always re-run the typechecker after importing a package,
61 // even though we know the imported data is valid. It's not ideal, but it's
62 // not causing any problems either.
64 // - gc/typecheck is still in charge of some transformations, such as rewriting
65 // multi-valued function calls or transforming ir.OINDEX to ir.OINDEXMAP.
67 // Using the syntax tree with types2, which has a complete representation of generics,
68 // the unified IR has the full typed AST needed for introspection during step (1).
69 // In other words, we have all the necessary information to build the generic IR form
70 // (see writer.captureVars for an example).
71 func unified(noders []*noder) {
72 inline.NewInline = InlineCall
74 data := writePkgStub(noders)
76 // We already passed base.Flag.Lang to types2 to handle validating
77 // the user's source code. Bump it up now to the current version and
78 // re-parse, so typecheck doesn't complain if we construct IR that
79 // utilizes newer Go features.
80 base.Flag.Lang = fmt.Sprintf("go1.%d", goversion.Version)
83 target := typecheck.Target
85 typecheck.TypecheckAllowed = true
87 localPkgReader = newPkgReader(pkgbits.NewPkgDecoder(types.LocalPkg.Path, data))
88 readPackage(localPkgReader, types.LocalPkg, true)
90 r := localPkgReader.newReader(pkgbits.RelocMeta, pkgbits.PrivateRootIdx, pkgbits.SyncPrivate)
91 r.pkgInit(types.LocalPkg, target)
93 // Type-check any top-level assignments. We ignore non-assignments
94 // here because other declarations are typechecked as they're
96 for i, ndecls := 0, len(target.Decls); i < ndecls; i++ {
97 switch n := target.Decls[i]; n.Op() {
99 target.Decls[i] = typecheck.Stmt(n)
105 // Check that nothing snuck past typechecking.
106 for _, n := range target.Decls {
107 if n.Typecheck() == 0 {
108 base.FatalfAt(n.Pos(), "missed typecheck: %v", n)
111 // For functions, check that at least their first statement (if
112 // any) was typechecked too.
113 if fn, ok := n.(*ir.Func); ok && len(fn.Body) != 0 {
114 if stmt := fn.Body[0]; stmt.Typecheck() == 0 {
115 base.FatalfAt(stmt.Pos(), "missed typecheck: %v", stmt)
120 base.ExitIfErrors() // just in case
123 // readBodies reads in bodies for any
124 func readBodies(target *ir.Package) {
125 // Don't use range--bodyIdx can add closures to todoBodies.
126 for len(todoBodies) > 0 {
127 // The order we expand bodies doesn't matter, so pop from the end
128 // to reduce todoBodies reallocations if it grows further.
129 fn := todoBodies[len(todoBodies)-1]
130 todoBodies = todoBodies[:len(todoBodies)-1]
132 pri, ok := bodyReader[fn]
136 // Instantiated generic function: add to Decls for typechecking
138 if fn.OClosure == nil && len(pri.dict.targs) != 0 {
139 target.Decls = append(target.Decls, fn)
145 // writePkgStub type checks the given parsed source files,
146 // writes an export data package stub representing them,
147 // and returns the result.
148 func writePkgStub(noders []*noder) string {
149 m, pkg, info := checkFiles(noders)
151 pw := newPkgWriter(m, pkg, info)
153 pw.collectDecls(noders)
155 publicRootWriter := pw.newWriter(pkgbits.RelocMeta, pkgbits.SyncPublic)
156 privateRootWriter := pw.newWriter(pkgbits.RelocMeta, pkgbits.SyncPrivate)
158 assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
159 assert(privateRootWriter.Idx == pkgbits.PrivateRootIdx)
162 w := publicRootWriter
164 w.Bool(false) // has init; XXX
167 names := scope.Names()
169 for _, name := range scope.Names() {
170 w.obj(scope.Lookup(name), nil)
173 w.Sync(pkgbits.SyncEOF)
178 w := privateRootWriter
183 var sb bytes.Buffer // TODO(mdempsky): strings.Builder after #44505 is resolved
186 // At this point, we're done with types2. Make sure the package is
187 // garbage collected.
193 // freePackage ensures the given package is garbage collected.
194 func freePackage(pkg *types2.Package) {
195 // The GC test below relies on a precise GC that runs finalizers as
196 // soon as objects are unreachable. Our implementation provides
197 // this, but other/older implementations may not (e.g., Go 1.4 does
198 // not because of #22350). To avoid imposing unnecessary
199 // restrictions on the GOROOT_BOOTSTRAP toolchain, we skip the test
200 // during bootstrapping.
201 if base.CompilerBootstrap {
205 // Set a finalizer on pkg so we can detect if/when it's collected.
206 done := make(chan struct{})
207 runtime.SetFinalizer(pkg, func(*types2.Package) { close(done) })
209 // Important: objects involved in cycles are not finalized, so zero
210 // out pkg to break its cycles and allow the finalizer to run.
211 *pkg = types2.Package{}
213 // It typically takes just 1 or 2 cycles to release pkg, but it
214 // doesn't hurt to try a few more times.
215 for i := 0; i < 10; i++ {
224 base.Fatalf("package never finalized")
227 // readPackage reads package export data from pr to populate
230 // localStub indicates whether pr is reading the stub export data for
231 // the local package, as opposed to relocated export data for an
233 func readPackage(pr *pkgReader, importpkg *types.Pkg, localStub bool) {
235 r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
238 base.Assertf(pkg == importpkg, "have package %q (%p), want package %q (%p)", pkg.Path, pkg, importpkg.Path, importpkg)
241 sym := pkg.Lookup(".inittask")
242 task := ir.NewNameAt(src.NoXPos, sym)
243 task.Class = ir.PEXTERN
247 for i, n := 0, r.Len(); i < n; i++ {
248 r.Sync(pkgbits.SyncObject)
250 idx := r.Reloc(pkgbits.RelocObj)
253 path, name, code := r.p.PeekObj(idx)
254 if code != pkgbits.ObjStub {
255 objReader[types.NewPkg(path, "").Lookup(name)] = pkgReaderIndex{pr, idx, nil}
259 r.Sync(pkgbits.SyncEOF)
263 r := pr.newReader(pkgbits.RelocMeta, pkgbits.PrivateRootIdx, pkgbits.SyncPrivate)
265 for i, n := 0, r.Len(); i < n; i++ {
268 idx := r.Reloc(pkgbits.RelocBody)
270 sym := types.NewPkg(path, "").Lookup(name)
271 if _, ok := importBodyReader[sym]; !ok {
272 importBodyReader[sym] = pkgReaderIndex{pr, idx, nil}
276 r.Sync(pkgbits.SyncEOF)
280 // writeUnifiedExport writes to `out` the finalized, self-contained
281 // Unified IR export data file for the current compilation unit.
282 func writeUnifiedExport(out io.Writer) {
284 pw: pkgbits.NewPkgEncoder(base.Debug.SyncFrames),
286 pkgs: make(map[string]pkgbits.Index),
287 decls: make(map[*types.Sym]pkgbits.Index),
288 bodies: make(map[*types.Sym]pkgbits.Index),
291 publicRootWriter := l.pw.NewEncoder(pkgbits.RelocMeta, pkgbits.SyncPublic)
292 privateRootWriter := l.pw.NewEncoder(pkgbits.RelocMeta, pkgbits.SyncPrivate)
293 assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
294 assert(privateRootWriter.Idx == pkgbits.PrivateRootIdx)
296 var selfPkgIdx pkgbits.Index
300 r := pr.NewDecoder(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
302 r.Sync(pkgbits.SyncPkg)
303 selfPkgIdx = l.relocIdx(pr, pkgbits.RelocPkg, r.Reloc(pkgbits.RelocPkg))
307 for i, n := 0, r.Len(); i < n; i++ {
308 r.Sync(pkgbits.SyncObject)
310 idx := r.Reloc(pkgbits.RelocObj)
313 xpath, xname, xtag := pr.PeekObj(idx)
314 assert(xpath == pr.PkgPath())
315 assert(xtag != pkgbits.ObjStub)
317 if types.IsExported(xname) {
318 l.relocIdx(pr, pkgbits.RelocObj, idx)
322 r.Sync(pkgbits.SyncEOF)
326 var idxs []pkgbits.Index
327 for _, idx := range l.decls {
328 idxs = append(idxs, idx)
330 sort.Slice(idxs, func(i, j int) bool { return idxs[i] < idxs[j] })
332 w := publicRootWriter
334 w.Sync(pkgbits.SyncPkg)
335 w.Reloc(pkgbits.RelocPkg, selfPkgIdx)
337 w.Bool(typecheck.Lookup(".inittask").Def != nil)
340 for _, idx := range idxs {
341 w.Sync(pkgbits.SyncObject)
343 w.Reloc(pkgbits.RelocObj, idx)
347 w.Sync(pkgbits.SyncEOF)
357 for sym, idx := range l.bodies {
358 bodies = append(bodies, symIdx{sym, idx})
360 sort.Slice(bodies, func(i, j int) bool { return bodies[i].idx < bodies[j].idx })
362 w := privateRootWriter
365 for _, body := range bodies {
366 w.String(body.sym.Pkg.Path)
367 w.String(body.sym.Name)
368 w.Reloc(pkgbits.RelocBody, body.idx)
371 w.Sync(pkgbits.SyncEOF)
375 base.Ctxt.Fingerprint = l.pw.DumpTo(out)