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 iteratively expands all pending dictionaries and
125 func readBodies(target *ir.Package) {
126 // Don't use range--bodyIdx can add closures to todoBodies.
128 // The order we expand dictionaries and bodies doesn't matter, so
129 // pop from the end to reduce todoBodies reallocations if it grows
132 // However, we do at least need to flush any pending dictionaries
133 // before reading bodies, because bodies might reference the
136 if len(todoDicts) > 0 {
137 fn := todoDicts[len(todoDicts)-1]
138 todoDicts = todoDicts[:len(todoDicts)-1]
143 if len(todoBodies) > 0 {
144 fn := todoBodies[len(todoBodies)-1]
145 todoBodies = todoBodies[:len(todoBodies)-1]
147 pri, ok := bodyReader[fn]
151 // Instantiated generic function: add to Decls for typechecking
153 if fn.OClosure == nil && len(pri.dict.targs) != 0 {
154 target.Decls = append(target.Decls, fn)
167 // writePkgStub type checks the given parsed source files,
168 // writes an export data package stub representing them,
169 // and returns the result.
170 func writePkgStub(noders []*noder) string {
171 m, pkg, info := checkFiles(noders)
173 pw := newPkgWriter(m, pkg, info)
175 pw.collectDecls(noders)
177 publicRootWriter := pw.newWriter(pkgbits.RelocMeta, pkgbits.SyncPublic)
178 privateRootWriter := pw.newWriter(pkgbits.RelocMeta, pkgbits.SyncPrivate)
180 assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
181 assert(privateRootWriter.Idx == pkgbits.PrivateRootIdx)
184 w := publicRootWriter
186 w.Bool(false) // TODO(mdempsky): Remove; was "has init"
189 names := scope.Names()
191 for _, name := range names {
192 w.obj(scope.Lookup(name), nil)
195 w.Sync(pkgbits.SyncEOF)
200 w := privateRootWriter
205 var sb strings.Builder
208 // At this point, we're done with types2. Make sure the package is
209 // garbage collected.
215 // freePackage ensures the given package is garbage collected.
216 func freePackage(pkg *types2.Package) {
217 // The GC test below relies on a precise GC that runs finalizers as
218 // soon as objects are unreachable. Our implementation provides
219 // this, but other/older implementations may not (e.g., Go 1.4 does
220 // not because of #22350). To avoid imposing unnecessary
221 // restrictions on the GOROOT_BOOTSTRAP toolchain, we skip the test
222 // during bootstrapping.
223 if base.CompilerBootstrap {
227 // Set a finalizer on pkg so we can detect if/when it's collected.
228 done := make(chan struct{})
229 runtime.SetFinalizer(pkg, func(*types2.Package) { close(done) })
231 // Important: objects involved in cycles are not finalized, so zero
232 // out pkg to break its cycles and allow the finalizer to run.
233 *pkg = types2.Package{}
235 // It typically takes just 1 or 2 cycles to release pkg, but it
236 // doesn't hurt to try a few more times.
237 for i := 0; i < 10; i++ {
246 base.Fatalf("package never finalized")
249 // readPackage reads package export data from pr to populate
252 // localStub indicates whether pr is reading the stub export data for
253 // the local package, as opposed to relocated export data for an
255 func readPackage(pr *pkgReader, importpkg *types.Pkg, localStub bool) {
257 r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
260 base.Assertf(pkg == importpkg, "have package %q (%p), want package %q (%p)", pkg.Path, pkg, importpkg.Path, importpkg)
262 r.Bool() // TODO(mdempsky): Remove; was "has init"
264 for i, n := 0, r.Len(); i < n; i++ {
265 r.Sync(pkgbits.SyncObject)
267 idx := r.Reloc(pkgbits.RelocObj)
270 path, name, code := r.p.PeekObj(idx)
271 if code != pkgbits.ObjStub {
272 objReader[types.NewPkg(path, "").Lookup(name)] = pkgReaderIndex{pr, idx, nil, nil, nil}
276 r.Sync(pkgbits.SyncEOF)
280 r := pr.newReader(pkgbits.RelocMeta, pkgbits.PrivateRootIdx, pkgbits.SyncPrivate)
283 sym := importpkg.Lookup(".inittask")
284 task := ir.NewNameAt(src.NoXPos, sym)
285 task.Class = ir.PEXTERN
289 for i, n := 0, r.Len(); i < n; i++ {
292 idx := r.Reloc(pkgbits.RelocBody)
294 sym := types.NewPkg(path, "").Lookup(name)
295 if _, ok := importBodyReader[sym]; !ok {
296 importBodyReader[sym] = pkgReaderIndex{pr, idx, nil, nil, nil}
300 r.Sync(pkgbits.SyncEOF)
304 // writeUnifiedExport writes to `out` the finalized, self-contained
305 // Unified IR export data file for the current compilation unit.
306 func writeUnifiedExport(out io.Writer) {
308 pw: pkgbits.NewPkgEncoder(base.Debug.SyncFrames),
310 pkgs: make(map[string]pkgbits.Index),
311 decls: make(map[*types.Sym]pkgbits.Index),
312 bodies: make(map[*types.Sym]pkgbits.Index),
315 publicRootWriter := l.pw.NewEncoder(pkgbits.RelocMeta, pkgbits.SyncPublic)
316 privateRootWriter := l.pw.NewEncoder(pkgbits.RelocMeta, pkgbits.SyncPrivate)
317 assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
318 assert(privateRootWriter.Idx == pkgbits.PrivateRootIdx)
320 var selfPkgIdx pkgbits.Index
324 r := pr.NewDecoder(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
326 r.Sync(pkgbits.SyncPkg)
327 selfPkgIdx = l.relocIdx(pr, pkgbits.RelocPkg, r.Reloc(pkgbits.RelocPkg))
329 r.Bool() // TODO(mdempsky): Remove; was "has init"
331 for i, n := 0, r.Len(); i < n; i++ {
332 r.Sync(pkgbits.SyncObject)
334 idx := r.Reloc(pkgbits.RelocObj)
337 xpath, xname, xtag := pr.PeekObj(idx)
338 assert(xpath == pr.PkgPath())
339 assert(xtag != pkgbits.ObjStub)
341 if types.IsExported(xname) {
342 l.relocIdx(pr, pkgbits.RelocObj, idx)
346 r.Sync(pkgbits.SyncEOF)
350 var idxs []pkgbits.Index
351 for _, idx := range l.decls {
352 idxs = append(idxs, idx)
354 sort.Slice(idxs, func(i, j int) bool { return idxs[i] < idxs[j] })
356 w := publicRootWriter
358 w.Sync(pkgbits.SyncPkg)
359 w.Reloc(pkgbits.RelocPkg, selfPkgIdx)
360 w.Bool(false) // TODO(mdempsky): Remove; was "has init"
363 for _, idx := range idxs {
364 w.Sync(pkgbits.SyncObject)
366 w.Reloc(pkgbits.RelocObj, idx)
370 w.Sync(pkgbits.SyncEOF)
380 for sym, idx := range l.bodies {
381 bodies = append(bodies, symIdx{sym, idx})
383 sort.Slice(bodies, func(i, j int) bool { return bodies[i].idx < bodies[j].idx })
385 w := privateRootWriter
387 w.Bool(typecheck.Lookup(".inittask").Def != nil)
390 for _, body := range bodies {
391 w.String(body.sym.Pkg.Path)
392 w.String(body.sym.Name)
393 w.Reloc(pkgbits.RelocBody, body.idx)
396 w.Sync(pkgbits.SyncEOF)
400 base.Ctxt.Fingerprint = l.pw.DumpTo(out)