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 assert(types.LocalPkg.Path == "")
86 types.LocalPkg.Height = 0 // reset so pkgReader.pkgIdx doesn't complain
87 target := typecheck.Target
89 typecheck.TypecheckAllowed = true
91 localPkgReader = newPkgReader(pkgbits.NewPkgDecoder(types.LocalPkg.Path, data))
92 readPackage(localPkgReader, types.LocalPkg)
94 r := localPkgReader.newReader(pkgbits.RelocMeta, pkgbits.PrivateRootIdx, pkgbits.SyncPrivate)
95 r.pkgInit(types.LocalPkg, target)
97 // Type-check any top-level assignments. We ignore non-assignments
98 // here because other declarations are typechecked as they're
100 for i, ndecls := 0, len(target.Decls); i < ndecls; i++ {
101 switch n := target.Decls[i]; n.Op() {
102 case ir.OAS, ir.OAS2:
103 target.Decls[i] = typecheck.Stmt(n)
109 // Check that nothing snuck past typechecking.
110 for _, n := range target.Decls {
111 if n.Typecheck() == 0 {
112 base.FatalfAt(n.Pos(), "missed typecheck: %v", n)
115 // For functions, check that at least their first statement (if
116 // any) was typechecked too.
117 if fn, ok := n.(*ir.Func); ok && len(fn.Body) != 0 {
118 if stmt := fn.Body[0]; stmt.Typecheck() == 0 {
119 base.FatalfAt(stmt.Pos(), "missed typecheck: %v", stmt)
124 base.ExitIfErrors() // just in case
127 // readBodies reads in bodies for any
128 func readBodies(target *ir.Package) {
129 // Don't use range--bodyIdx can add closures to todoBodies.
130 for len(todoBodies) > 0 {
131 // The order we expand bodies doesn't matter, so pop from the end
132 // to reduce todoBodies reallocations if it grows further.
133 fn := todoBodies[len(todoBodies)-1]
134 todoBodies = todoBodies[:len(todoBodies)-1]
136 pri, ok := bodyReader[fn]
140 // Instantiated generic function: add to Decls for typechecking
142 if fn.OClosure == nil && len(pri.dict.targs) != 0 {
143 target.Decls = append(target.Decls, fn)
149 // writePkgStub type checks the given parsed source files,
150 // writes an export data package stub representing them,
151 // and returns the result.
152 func writePkgStub(noders []*noder) string {
153 m, pkg, info := checkFiles(noders)
155 pw := newPkgWriter(m, pkg, info)
157 pw.collectDecls(noders)
159 publicRootWriter := pw.newWriter(pkgbits.RelocMeta, pkgbits.SyncPublic)
160 privateRootWriter := pw.newWriter(pkgbits.RelocMeta, pkgbits.SyncPrivate)
162 assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
163 assert(privateRootWriter.Idx == pkgbits.PrivateRootIdx)
166 w := publicRootWriter
168 w.Bool(false) // has init; XXX
171 names := scope.Names()
173 for _, name := range scope.Names() {
174 w.obj(scope.Lookup(name), nil)
177 w.Sync(pkgbits.SyncEOF)
182 w := privateRootWriter
187 var sb bytes.Buffer // TODO(mdempsky): strings.Builder after #44505 is resolved
190 // At this point, we're done with types2. Make sure the package is
191 // garbage collected.
197 // freePackage ensures the given package is garbage collected.
198 func freePackage(pkg *types2.Package) {
199 // The GC test below relies on a precise GC that runs finalizers as
200 // soon as objects are unreachable. Our implementation provides
201 // this, but other/older implementations may not (e.g., Go 1.4 does
202 // not because of #22350). To avoid imposing unnecessary
203 // restrictions on the GOROOT_BOOTSTRAP toolchain, we skip the test
204 // during bootstrapping.
205 if base.CompilerBootstrap {
209 // Set a finalizer on pkg so we can detect if/when it's collected.
210 done := make(chan struct{})
211 runtime.SetFinalizer(pkg, func(*types2.Package) { close(done) })
213 // Important: objects involved in cycles are not finalized, so zero
214 // out pkg to break its cycles and allow the finalizer to run.
215 *pkg = types2.Package{}
217 // It typically takes just 1 or 2 cycles to release pkg, but it
218 // doesn't hurt to try a few more times.
219 for i := 0; i < 10; i++ {
228 base.Fatalf("package never finalized")
231 func readPackage(pr *pkgReader, importpkg *types.Pkg) {
232 r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
235 base.Assertf(pkg == importpkg, "have package %q (%p), want package %q (%p)", pkg.Path, pkg, importpkg.Path, importpkg)
238 sym := pkg.Lookup(".inittask")
239 task := ir.NewNameAt(src.NoXPos, sym)
240 task.Class = ir.PEXTERN
244 for i, n := 0, r.Len(); i < n; i++ {
245 r.Sync(pkgbits.SyncObject)
247 idx := r.Reloc(pkgbits.RelocObj)
250 path, name, code := r.p.PeekObj(idx)
251 if code != pkgbits.ObjStub {
252 objReader[types.NewPkg(path, "").Lookup(name)] = pkgReaderIndex{pr, idx, nil}
257 func writeUnifiedExport(out io.Writer) {
259 pw: pkgbits.NewPkgEncoder(base.Debug.SyncFrames),
261 pkgs: make(map[string]int),
262 decls: make(map[*types.Sym]int),
265 publicRootWriter := l.pw.NewEncoder(pkgbits.RelocMeta, pkgbits.SyncPublic)
266 assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
272 r := pr.NewDecoder(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
274 r.Sync(pkgbits.SyncPkg)
275 selfPkgIdx = l.relocIdx(pr, pkgbits.RelocPkg, r.Reloc(pkgbits.RelocPkg))
279 for i, n := 0, r.Len(); i < n; i++ {
280 r.Sync(pkgbits.SyncObject)
282 idx := r.Reloc(pkgbits.RelocObj)
285 xpath, xname, xtag := pr.PeekObj(idx)
286 assert(xpath == pr.PkgPath())
287 assert(xtag != pkgbits.ObjStub)
289 if types.IsExported(xname) {
290 l.relocIdx(pr, pkgbits.RelocObj, idx)
294 r.Sync(pkgbits.SyncEOF)
299 for _, idx := range l.decls {
300 idxs = append(idxs, idx)
304 w := publicRootWriter
306 w.Sync(pkgbits.SyncPkg)
307 w.Reloc(pkgbits.RelocPkg, selfPkgIdx)
309 w.Bool(typecheck.Lookup(".inittask").Def != nil)
312 for _, idx := range idxs {
313 w.Sync(pkgbits.SyncObject)
315 w.Reloc(pkgbits.RelocObj, idx)
319 w.Sync(pkgbits.SyncEOF)
323 base.Ctxt.Fingerprint = l.pw.DumpTo(out)