3 // Copyright 2021 The Go Authors. All rights reserved.
4 // Use of this source code is governed by a BSD-style
5 // license that can be found in the LICENSE file.
18 "cmd/compile/internal/base"
19 "cmd/compile/internal/inline"
20 "cmd/compile/internal/ir"
21 "cmd/compile/internal/typecheck"
22 "cmd/compile/internal/types"
23 "cmd/compile/internal/types2"
27 // localPkgReader holds the package reader used for reading the local
28 // package. It exists so the unified IR linker can refer back to it
30 var localPkgReader *pkgReader
32 // unified construct the local package's IR from syntax's AST.
34 // The pipeline contains 2 steps:
36 // (1) Generate package export data "stub".
38 // (2) Generate package IR from package export data.
40 // The package data "stub" at step (1) contains everything from the local package,
41 // but nothing that have been imported. When we're actually writing out export data
42 // to the output files (see writeNewExport function), we run the "linker", which does
45 // + Updates compiler extensions data (e.g., inlining cost, escape analysis results).
47 // + Handles re-exporting any transitive dependencies.
49 // + Prunes out any unnecessary details (e.g., non-inlineable functions, because any
50 // downstream importers only care about inlinable functions).
52 // The source files are typechecked twice, once before writing export data
53 // using types2 checker, once after read export data using gc/typecheck.
54 // This duplication of work will go away once we always use types2 checker,
55 // we can remove the gc/typecheck pass. The reason it is still here:
57 // + It reduces engineering costs in maintaining a fork of typecheck
58 // (e.g., no need to backport fixes like CL 327651).
60 // + It makes it easier to pass toolstash -cmp.
62 // + Historically, we would always re-run the typechecker after import, even though
63 // we know the imported data is valid. It's not ideal, but also not causing any
66 // + There's still transformation that being done during gc/typecheck, like rewriting
67 // multi-valued function call, or transform ir.OINDEX -> ir.OINDEXMAP.
69 // Using syntax+types2 tree, which already has a complete representation of generics,
70 // the unified IR has the full typed AST for doing introspection during step (1).
71 // In other words, we have all necessary information to build the generic IR form
72 // (see writer.captureVars for an example).
73 func unified(noders []*noder) {
74 inline.NewInline = InlineCall
76 writeNewExportFunc = writeNewExport
78 newReadImportFunc = func(data string, pkg1 *types.Pkg, ctxt *types2.Context, packages map[string]*types2.Package) (pkg2 *types2.Package, err error) {
79 pr := pkgbits.NewPkgDecoder(pkg1.Path, data)
81 // Read package descriptors for both types2 and compiler backend.
82 readPackage(newPkgReader(pr), pkg1)
83 pkg2 = readPackage2(ctxt, packages, pr)
87 data := writePkgStub(noders)
89 // We already passed base.Flag.Lang to types2 to handle validating
90 // the user's source code. Bump it up now to the current version and
91 // re-parse, so typecheck doesn't complain if we construct IR that
92 // utilizes newer Go features.
93 base.Flag.Lang = fmt.Sprintf("go1.%d", goversion.Version)
96 assert(types.LocalPkg.Path == "")
97 types.LocalPkg.Height = 0 // reset so pkgReader.pkgIdx doesn't complain
98 target := typecheck.Target
100 typecheck.TypecheckAllowed = true
102 localPkgReader = newPkgReader(pkgbits.NewPkgDecoder(types.LocalPkg.Path, data))
103 readPackage(localPkgReader, types.LocalPkg)
105 r := localPkgReader.newReader(pkgbits.RelocMeta, pkgbits.PrivateRootIdx, pkgbits.SyncPrivate)
106 r.pkgInit(types.LocalPkg, target)
108 // Type-check any top-level assignments. We ignore non-assignments
109 // here because other declarations are typechecked as they're
111 for i, ndecls := 0, len(target.Decls); i < ndecls; i++ {
112 switch n := target.Decls[i]; n.Op() {
113 case ir.OAS, ir.OAS2:
114 target.Decls[i] = typecheck.Stmt(n)
118 // Don't use range--bodyIdx can add closures to todoBodies.
119 for len(todoBodies) > 0 {
120 // The order we expand bodies doesn't matter, so pop from the end
121 // to reduce todoBodies reallocations if it grows further.
122 fn := todoBodies[len(todoBodies)-1]
123 todoBodies = todoBodies[:len(todoBodies)-1]
125 pri, ok := bodyReader[fn]
129 // Instantiated generic function: add to Decls for typechecking
131 if fn.OClosure == nil && len(pri.dict.targs) != 0 {
132 target.Decls = append(target.Decls, fn)
136 todoBodiesDone = true
138 // Check that nothing snuck past typechecking.
139 for _, n := range target.Decls {
140 if n.Typecheck() == 0 {
141 base.FatalfAt(n.Pos(), "missed typecheck: %v", n)
144 // For functions, check that at least their first statement (if
145 // any) was typechecked too.
146 if fn, ok := n.(*ir.Func); ok && len(fn.Body) != 0 {
147 if stmt := fn.Body[0]; stmt.Typecheck() == 0 {
148 base.FatalfAt(stmt.Pos(), "missed typecheck: %v", stmt)
153 base.ExitIfErrors() // just in case
156 // writePkgStub type checks the given parsed source files,
157 // writes an export data package stub representing them,
158 // and returns the result.
159 func writePkgStub(noders []*noder) string {
160 m, pkg, info := checkFiles(noders)
162 pw := newPkgWriter(m, pkg, info)
164 pw.collectDecls(noders)
166 publicRootWriter := pw.newWriter(pkgbits.RelocMeta, pkgbits.SyncPublic)
167 privateRootWriter := pw.newWriter(pkgbits.RelocMeta, pkgbits.SyncPrivate)
169 assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
170 assert(privateRootWriter.Idx == pkgbits.PrivateRootIdx)
173 w := publicRootWriter
175 w.Bool(false) // has init; XXX
178 names := scope.Names()
180 for _, name := range scope.Names() {
181 w.obj(scope.Lookup(name), nil)
184 w.Sync(pkgbits.SyncEOF)
189 w := privateRootWriter
194 var sb bytes.Buffer // TODO(mdempsky): strings.Builder after #44505 is resolved
197 // At this point, we're done with types2. Make sure the package is
198 // garbage collected.
204 // freePackage ensures the given package is garbage collected.
205 func freePackage(pkg *types2.Package) {
206 // The GC test below relies on a precise GC that runs finalizers as
207 // soon as objects are unreachable. Our implementation provides
208 // this, but other/older implementations may not (e.g., Go 1.4 does
209 // not because of #22350). To avoid imposing unnecessary
210 // restrictions on the GOROOT_BOOTSTRAP toolchain, we skip the test
211 // during bootstrapping.
212 if base.CompilerBootstrap {
216 // Set a finalizer on pkg so we can detect if/when it's collected.
217 done := make(chan struct{})
218 runtime.SetFinalizer(pkg, func(*types2.Package) { close(done) })
220 // Important: objects involved in cycles are not finalized, so zero
221 // out pkg to break its cycles and allow the finalizer to run.
222 *pkg = types2.Package{}
224 // It typically takes just 1 or 2 cycles to release pkg, but it
225 // doesn't hurt to try a few more times.
226 for i := 0; i < 10; i++ {
235 base.Fatalf("package never finalized")
238 func readPackage(pr *pkgReader, importpkg *types.Pkg) {
239 r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
242 assert(pkg == importpkg)
245 sym := pkg.Lookup(".inittask")
246 task := ir.NewNameAt(src.NoXPos, sym)
247 task.Class = ir.PEXTERN
251 for i, n := 0, r.Len(); i < n; i++ {
252 r.Sync(pkgbits.SyncObject)
254 idx := r.Reloc(pkgbits.RelocObj)
257 path, name, code := r.p.PeekObj(idx)
258 if code != pkgbits.ObjStub {
259 objReader[types.NewPkg(path, "").Lookup(name)] = pkgReaderIndex{pr, idx, nil}
264 func writeNewExport(out io.Writer) {
266 pw: pkgbits.NewPkgEncoder(base.Debug.SyncFrames),
268 pkgs: make(map[string]int),
269 decls: make(map[*types.Sym]int),
272 publicRootWriter := l.pw.NewEncoder(pkgbits.RelocMeta, pkgbits.SyncPublic)
273 assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
279 r := pr.NewDecoder(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
281 r.Sync(pkgbits.SyncPkg)
282 selfPkgIdx = l.relocIdx(pr, pkgbits.RelocPkg, r.Reloc(pkgbits.RelocPkg))
286 for i, n := 0, r.Len(); i < n; i++ {
287 r.Sync(pkgbits.SyncObject)
289 idx := r.Reloc(pkgbits.RelocObj)
292 xpath, xname, xtag := pr.PeekObj(idx)
293 assert(xpath == pr.PkgPath())
294 assert(xtag != pkgbits.ObjStub)
296 if types.IsExported(xname) {
297 l.relocIdx(pr, pkgbits.RelocObj, idx)
301 r.Sync(pkgbits.SyncEOF)
306 for _, idx := range l.decls {
307 idxs = append(idxs, idx)
311 w := publicRootWriter
313 w.Sync(pkgbits.SyncPkg)
314 w.Reloc(pkgbits.RelocPkg, selfPkgIdx)
316 w.Bool(typecheck.Lookup(".inittask").Def != nil)
319 for _, idx := range idxs {
320 w.Sync(pkgbits.SyncObject)
322 w.Reloc(pkgbits.RelocObj, idx)
326 w.Sync(pkgbits.SyncEOF)