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/importer"
20 "cmd/compile/internal/inline"
21 "cmd/compile/internal/ir"
22 "cmd/compile/internal/typecheck"
23 "cmd/compile/internal/types"
24 "cmd/compile/internal/types2"
28 // localPkgReader holds the package reader used for reading the local
29 // package. It exists so the unified IR linker can refer back to it
31 var localPkgReader *pkgReader
33 // unified construct the local package's IR from syntax's AST.
35 // The pipeline contains 2 steps:
37 // 1) Generate package export data "stub".
39 // 2) Generate package IR from package export data.
41 // The package data "stub" at step (1) contains everything from the local package,
42 // but nothing that have been imported. When we're actually writing out export data
43 // to the output files (see writeNewExport function), we run the "linker", which does
46 // + Updates compiler extensions data (e.g., inlining cost, escape analysis results).
48 // + Handles re-exporting any transitive dependencies.
50 // + Prunes out any unnecessary details (e.g., non-inlineable functions, because any
51 // downstream importers only care about inlinable functions).
53 // The source files are typechecked twice, once before writing export data
54 // using types2 checker, once after read export data using gc/typecheck.
55 // This duplication of work will go away once we always use types2 checker,
56 // we can remove the gc/typecheck pass. The reason it is still here:
58 // + It reduces engineering costs in maintaining a fork of typecheck
59 // (e.g., no need to backport fixes like CL 327651).
61 // + It makes it easier to pass toolstash -cmp.
63 // + Historically, we would always re-run the typechecker after import, even though
64 // we know the imported data is valid. It's not ideal, but also not causing any
67 // + There's still transformation that being done during gc/typecheck, like rewriting
68 // multi-valued function call, or transform ir.OINDEX -> ir.OINDEXMAP.
70 // Using syntax+types2 tree, which already has a complete representation of generics,
71 // the unified IR has the full typed AST for doing introspection during step (1).
72 // In other words, we have all necessary information to build the generic IR form
73 // (see writer.captureVars for an example).
74 func unified(noders []*noder) {
75 inline.NewInline = InlineCall
77 writeNewExportFunc = writeNewExport
79 newReadImportFunc = func(data string, pkg1 *types.Pkg, ctxt *types2.Context, packages map[string]*types2.Package) (pkg2 *types2.Package, err error) {
80 pr := pkgbits.NewPkgDecoder(pkg1.Path, data)
82 // Read package descriptors for both types2 and compiler backend.
83 readPackage(newPkgReader(pr), pkg1)
84 pkg2 = importer.ReadPackage(ctxt, packages, pr)
88 data := writePkgStub(noders)
90 // We already passed base.Flag.Lang to types2 to handle validating
91 // the user's source code. Bump it up now to the current version and
92 // re-parse, so typecheck doesn't complain if we construct IR that
93 // utilizes newer Go features.
94 base.Flag.Lang = fmt.Sprintf("go1.%d", goversion.Version)
97 assert(types.LocalPkg.Path == "")
98 types.LocalPkg.Height = 0 // reset so pkgReader.pkgIdx doesn't complain
99 target := typecheck.Target
101 typecheck.TypecheckAllowed = true
103 localPkgReader = newPkgReader(pkgbits.NewPkgDecoder(types.LocalPkg.Path, data))
104 readPackage(localPkgReader, types.LocalPkg)
106 r := localPkgReader.newReader(pkgbits.RelocMeta, pkgbits.PrivateRootIdx, pkgbits.SyncPrivate)
107 r.pkgInit(types.LocalPkg, target)
109 // Type-check any top-level assignments. We ignore non-assignments
110 // here because other declarations are typechecked as they're
112 for i, ndecls := 0, len(target.Decls); i < ndecls; i++ {
113 switch n := target.Decls[i]; n.Op() {
114 case ir.OAS, ir.OAS2:
115 target.Decls[i] = typecheck.Stmt(n)
121 // Check that nothing snuck past typechecking.
122 for _, n := range target.Decls {
123 if n.Typecheck() == 0 {
124 base.FatalfAt(n.Pos(), "missed typecheck: %v", n)
127 // For functions, check that at least their first statement (if
128 // any) was typechecked too.
129 if fn, ok := n.(*ir.Func); ok && len(fn.Body) != 0 {
130 if stmt := fn.Body[0]; stmt.Typecheck() == 0 {
131 base.FatalfAt(stmt.Pos(), "missed typecheck: %v", stmt)
136 base.ExitIfErrors() // just in case
139 // readBodies reads in bodies for any
140 func readBodies(target *ir.Package) {
141 // Don't use range--bodyIdx can add closures to todoBodies.
142 for len(todoBodies) > 0 {
143 // The order we expand bodies doesn't matter, so pop from the end
144 // to reduce todoBodies reallocations if it grows further.
145 fn := todoBodies[len(todoBodies)-1]
146 todoBodies = todoBodies[:len(todoBodies)-1]
148 pri, ok := bodyReader[fn]
152 // Instantiated generic function: add to Decls for typechecking
154 if fn.OClosure == nil && len(pri.dict.targs) != 0 {
155 target.Decls = append(target.Decls, fn)
161 // writePkgStub type checks the given parsed source files,
162 // writes an export data package stub representing them,
163 // and returns the result.
164 func writePkgStub(noders []*noder) string {
165 m, pkg, info := checkFiles(noders)
167 pw := newPkgWriter(m, pkg, info)
169 pw.collectDecls(noders)
171 publicRootWriter := pw.newWriter(pkgbits.RelocMeta, pkgbits.SyncPublic)
172 privateRootWriter := pw.newWriter(pkgbits.RelocMeta, pkgbits.SyncPrivate)
174 assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
175 assert(privateRootWriter.Idx == pkgbits.PrivateRootIdx)
178 w := publicRootWriter
180 w.Bool(false) // has init; XXX
183 names := scope.Names()
185 for _, name := range scope.Names() {
186 w.obj(scope.Lookup(name), nil)
189 w.Sync(pkgbits.SyncEOF)
194 w := privateRootWriter
199 var sb bytes.Buffer // TODO(mdempsky): strings.Builder after #44505 is resolved
202 // At this point, we're done with types2. Make sure the package is
203 // garbage collected.
209 // freePackage ensures the given package is garbage collected.
210 func freePackage(pkg *types2.Package) {
211 // The GC test below relies on a precise GC that runs finalizers as
212 // soon as objects are unreachable. Our implementation provides
213 // this, but other/older implementations may not (e.g., Go 1.4 does
214 // not because of #22350). To avoid imposing unnecessary
215 // restrictions on the GOROOT_BOOTSTRAP toolchain, we skip the test
216 // during bootstrapping.
217 if base.CompilerBootstrap {
221 // Set a finalizer on pkg so we can detect if/when it's collected.
222 done := make(chan struct{})
223 runtime.SetFinalizer(pkg, func(*types2.Package) { close(done) })
225 // Important: objects involved in cycles are not finalized, so zero
226 // out pkg to break its cycles and allow the finalizer to run.
227 *pkg = types2.Package{}
229 // It typically takes just 1 or 2 cycles to release pkg, but it
230 // doesn't hurt to try a few more times.
231 for i := 0; i < 10; i++ {
240 base.Fatalf("package never finalized")
243 func readPackage(pr *pkgReader, importpkg *types.Pkg) {
244 r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
247 assert(pkg == importpkg)
250 sym := pkg.Lookup(".inittask")
251 task := ir.NewNameAt(src.NoXPos, sym)
252 task.Class = ir.PEXTERN
256 for i, n := 0, r.Len(); i < n; i++ {
257 r.Sync(pkgbits.SyncObject)
259 idx := r.Reloc(pkgbits.RelocObj)
262 path, name, code := r.p.PeekObj(idx)
263 if code != pkgbits.ObjStub {
264 objReader[types.NewPkg(path, "").Lookup(name)] = pkgReaderIndex{pr, idx, nil}
269 func writeNewExport(out io.Writer) {
271 pw: pkgbits.NewPkgEncoder(base.Debug.SyncFrames),
273 pkgs: make(map[string]int),
274 decls: make(map[*types.Sym]int),
277 publicRootWriter := l.pw.NewEncoder(pkgbits.RelocMeta, pkgbits.SyncPublic)
278 assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
284 r := pr.NewDecoder(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
286 r.Sync(pkgbits.SyncPkg)
287 selfPkgIdx = l.relocIdx(pr, pkgbits.RelocPkg, r.Reloc(pkgbits.RelocPkg))
291 for i, n := 0, r.Len(); i < n; i++ {
292 r.Sync(pkgbits.SyncObject)
294 idx := r.Reloc(pkgbits.RelocObj)
297 xpath, xname, xtag := pr.PeekObj(idx)
298 assert(xpath == pr.PkgPath())
299 assert(xtag != pkgbits.ObjStub)
301 if types.IsExported(xname) {
302 l.relocIdx(pr, pkgbits.RelocObj, idx)
306 r.Sync(pkgbits.SyncEOF)
311 for _, idx := range l.decls {
312 idxs = append(idxs, idx)
316 w := publicRootWriter
318 w.Sync(pkgbits.SyncPkg)
319 w.Reloc(pkgbits.RelocPkg, selfPkgIdx)
321 w.Bool(typecheck.Lookup(".inittask").Def != nil)
324 for _, idx := range idxs {
325 w.Sync(pkgbits.SyncObject)
327 w.Reloc(pkgbits.RelocObj, idx)
331 w.Sync(pkgbits.SyncEOF)