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 constructs the local package's Internal Representation (IR)
33 // from its syntax tree (AST).
35 // The pipeline contains 2 steps:
37 // 1. Generate the export data "stub".
39 // 2. Generate the IR from the export data above.
41 // The package data "stub" at step (1) contains everything from the local package,
42 // but nothing that has been imported. When we're actually writing out export data
43 // to the output files (see writeNewExport), we run the "linker", which:
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 the export data
53 // using types2, and again after reading the export data using gc/typecheck.
54 // The duplication of work will go away once we only use the types2 type checker,
55 // removing the gc/typecheck step. For now, it is kept because:
57 // - It reduces the 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 importing a package,
63 // even though we know the imported data is valid. It's not ideal, but it's
64 // not causing any problems either.
66 // - gc/typecheck is still in charge of some transformations, such as rewriting
67 // multi-valued function calls or transforming ir.OINDEX to ir.OINDEXMAP.
69 // Using the syntax tree with types2, which has a complete representation of generics,
70 // the unified IR has the full typed AST needed for introspection during step (1).
71 // In other words, we have all the 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 data := writePkgStub(noders)
78 // We already passed base.Flag.Lang to types2 to handle validating
79 // the user's source code. Bump it up now to the current version and
80 // re-parse, so typecheck doesn't complain if we construct IR that
81 // utilizes newer Go features.
82 base.Flag.Lang = fmt.Sprintf("go1.%d", goversion.Version)
85 types.LocalPkg.Height = 0 // reset so pkgReader.pkgIdx doesn't complain
86 target := typecheck.Target
88 typecheck.TypecheckAllowed = true
90 localPkgReader = newPkgReader(pkgbits.NewPkgDecoder(types.LocalPkg.Path, data))
91 readPackage(localPkgReader, types.LocalPkg)
93 r := localPkgReader.newReader(pkgbits.RelocMeta, pkgbits.PrivateRootIdx, pkgbits.SyncPrivate)
94 r.pkgInit(types.LocalPkg, target)
96 // Type-check any top-level assignments. We ignore non-assignments
97 // here because other declarations are typechecked as they're
99 for i, ndecls := 0, len(target.Decls); i < ndecls; i++ {
100 switch n := target.Decls[i]; n.Op() {
101 case ir.OAS, ir.OAS2:
102 target.Decls[i] = typecheck.Stmt(n)
108 // Check that nothing snuck past typechecking.
109 for _, n := range target.Decls {
110 if n.Typecheck() == 0 {
111 base.FatalfAt(n.Pos(), "missed typecheck: %v", n)
114 // For functions, check that at least their first statement (if
115 // any) was typechecked too.
116 if fn, ok := n.(*ir.Func); ok && len(fn.Body) != 0 {
117 if stmt := fn.Body[0]; stmt.Typecheck() == 0 {
118 base.FatalfAt(stmt.Pos(), "missed typecheck: %v", stmt)
123 base.ExitIfErrors() // just in case
126 // readBodies reads in bodies for any
127 func readBodies(target *ir.Package) {
128 // Don't use range--bodyIdx can add closures to todoBodies.
129 for len(todoBodies) > 0 {
130 // The order we expand bodies doesn't matter, so pop from the end
131 // to reduce todoBodies reallocations if it grows further.
132 fn := todoBodies[len(todoBodies)-1]
133 todoBodies = todoBodies[:len(todoBodies)-1]
135 pri, ok := bodyReader[fn]
139 // Instantiated generic function: add to Decls for typechecking
141 if fn.OClosure == nil && len(pri.dict.targs) != 0 {
142 target.Decls = append(target.Decls, fn)
148 // writePkgStub type checks the given parsed source files,
149 // writes an export data package stub representing them,
150 // and returns the result.
151 func writePkgStub(noders []*noder) string {
152 m, pkg, info := checkFiles(noders)
154 pw := newPkgWriter(m, pkg, info)
156 pw.collectDecls(noders)
158 publicRootWriter := pw.newWriter(pkgbits.RelocMeta, pkgbits.SyncPublic)
159 privateRootWriter := pw.newWriter(pkgbits.RelocMeta, pkgbits.SyncPrivate)
161 assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
162 assert(privateRootWriter.Idx == pkgbits.PrivateRootIdx)
165 w := publicRootWriter
167 w.Bool(false) // has init; XXX
170 names := scope.Names()
172 for _, name := range scope.Names() {
173 w.obj(scope.Lookup(name), nil)
176 w.Sync(pkgbits.SyncEOF)
181 w := privateRootWriter
186 var sb bytes.Buffer // TODO(mdempsky): strings.Builder after #44505 is resolved
189 // At this point, we're done with types2. Make sure the package is
190 // garbage collected.
196 // freePackage ensures the given package is garbage collected.
197 func freePackage(pkg *types2.Package) {
198 // The GC test below relies on a precise GC that runs finalizers as
199 // soon as objects are unreachable. Our implementation provides
200 // this, but other/older implementations may not (e.g., Go 1.4 does
201 // not because of #22350). To avoid imposing unnecessary
202 // restrictions on the GOROOT_BOOTSTRAP toolchain, we skip the test
203 // during bootstrapping.
204 if base.CompilerBootstrap {
208 // Set a finalizer on pkg so we can detect if/when it's collected.
209 done := make(chan struct{})
210 runtime.SetFinalizer(pkg, func(*types2.Package) { close(done) })
212 // Important: objects involved in cycles are not finalized, so zero
213 // out pkg to break its cycles and allow the finalizer to run.
214 *pkg = types2.Package{}
216 // It typically takes just 1 or 2 cycles to release pkg, but it
217 // doesn't hurt to try a few more times.
218 for i := 0; i < 10; i++ {
227 base.Fatalf("package never finalized")
230 func readPackage(pr *pkgReader, importpkg *types.Pkg) {
231 r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
234 base.Assertf(pkg == importpkg, "have package %q (%p), want package %q (%p)", pkg.Path, pkg, importpkg.Path, importpkg)
237 sym := pkg.Lookup(".inittask")
238 task := ir.NewNameAt(src.NoXPos, sym)
239 task.Class = ir.PEXTERN
243 for i, n := 0, r.Len(); i < n; i++ {
244 r.Sync(pkgbits.SyncObject)
246 idx := r.Reloc(pkgbits.RelocObj)
249 path, name, code := r.p.PeekObj(idx)
250 if code != pkgbits.ObjStub {
251 objReader[types.NewPkg(path, "").Lookup(name)] = pkgReaderIndex{pr, idx, nil}
256 func writeUnifiedExport(out io.Writer) {
258 pw: pkgbits.NewPkgEncoder(base.Debug.SyncFrames),
260 pkgs: make(map[string]int),
261 decls: make(map[*types.Sym]int),
264 publicRootWriter := l.pw.NewEncoder(pkgbits.RelocMeta, pkgbits.SyncPublic)
265 assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
271 r := pr.NewDecoder(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
273 r.Sync(pkgbits.SyncPkg)
274 selfPkgIdx = l.relocIdx(pr, pkgbits.RelocPkg, r.Reloc(pkgbits.RelocPkg))
278 for i, n := 0, r.Len(); i < n; i++ {
279 r.Sync(pkgbits.SyncObject)
281 idx := r.Reloc(pkgbits.RelocObj)
284 xpath, xname, xtag := pr.PeekObj(idx)
285 assert(xpath == pr.PkgPath())
286 assert(xtag != pkgbits.ObjStub)
288 if types.IsExported(xname) {
289 l.relocIdx(pr, pkgbits.RelocObj, idx)
293 r.Sync(pkgbits.SyncEOF)
298 for _, idx := range l.decls {
299 idxs = append(idxs, idx)
303 w := publicRootWriter
305 w.Sync(pkgbits.SyncPkg)
306 w.Reloc(pkgbits.RelocPkg, selfPkgIdx)
308 w.Bool(typecheck.Lookup(".inittask").Def != nil)
311 for _, idx := range idxs {
312 w.Sync(pkgbits.SyncObject)
314 w.Reloc(pkgbits.RelocObj, idx)
318 w.Sync(pkgbits.SyncEOF)
322 base.Ctxt.Fingerprint = l.pw.DumpTo(out)