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.
17 "cmd/compile/internal/base"
18 "cmd/compile/internal/inline"
19 "cmd/compile/internal/ir"
20 "cmd/compile/internal/typecheck"
21 "cmd/compile/internal/types"
22 "cmd/compile/internal/types2"
26 // localPkgReader holds the package reader used for reading the local
27 // package. It exists so the unified IR linker can refer back to it
29 var localPkgReader *pkgReader
31 // unified construct the local package's IR from syntax's AST.
33 // The pipeline contains 2 steps:
35 // (1) Generate package export data "stub".
37 // (2) Generate package IR from package export data.
39 // The package data "stub" at step (1) contains everything from the local package,
40 // but nothing that have been imported. When we're actually writing out export data
41 // to the output files (see writeNewExport function), we run the "linker", which does
44 // + Updates compiler extensions data (e.g., inlining cost, escape analysis results).
46 // + Handles re-exporting any transitive dependencies.
48 // + Prunes out any unnecessary details (e.g., non-inlineable functions, because any
49 // downstream importers only care about inlinable functions).
51 // The source files are typechecked twice, once before writing export data
52 // using types2 checker, once after read export data using gc/typecheck.
53 // This duplication of work will go away once we always use types2 checker,
54 // we can remove the gc/typecheck pass. The reason it is still here:
56 // + It reduces engineering costs in maintaining a fork of typecheck
57 // (e.g., no need to backport fixes like CL 327651).
59 // + It makes it easier to pass toolstash -cmp.
61 // + Historically, we would always re-run the typechecker after import, even though
62 // we know the imported data is valid. It's not ideal, but also not causing any
65 // + There's still transformation that being done during gc/typecheck, like rewriting
66 // multi-valued function call, or transform ir.OINDEX -> ir.OINDEXMAP.
68 // Using syntax+types2 tree, which already has a complete representation of generics,
69 // the unified IR has the full typed AST for doing introspection during step (1).
70 // In other words, we have all necessary information to build the generic IR form
71 // (see writer.captureVars for an example).
72 func unified(noders []*noder) {
73 inline.NewInline = InlineCall
76 writeNewExportFunc = writeNewExport
79 newReadImportFunc = func(data string, pkg1 *types.Pkg, check *types2.Checker, packages map[string]*types2.Package) (pkg2 *types2.Package, err error) {
80 pr := newPkgDecoder(pkg1.Path, data)
82 // Read package descriptors for both types2 and compiler backend.
83 readPackage(newPkgReader(pr), pkg1)
84 pkg2 = readPackage2(check, 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(newPkgDecoder(types.LocalPkg.Path, data))
104 readPackage(localPkgReader, types.LocalPkg)
106 r := localPkgReader.newReader(relocMeta, privateRootIdx, syncPrivate)
108 r.pkgInit(types.LocalPkg, target)
110 // Don't use range--bodyIdx can add closures to todoBodies.
111 for len(todoBodies) > 0 {
112 // The order we expand bodies doesn't matter, so pop from the end
113 // to reduce todoBodies reallocations if it grows further.
114 fn := todoBodies[len(todoBodies)-1]
115 todoBodies = todoBodies[:len(todoBodies)-1]
117 pri, ok := bodyReader[fn]
121 // Instantiated generic function: add to Decls for typechecking
123 if len(pri.implicits) != 0 && fn.OClosure == nil {
124 target.Decls = append(target.Decls, fn)
129 // Don't use range--typecheck can add closures to Target.Decls.
130 for i := 0; i < len(target.Decls); i++ {
131 target.Decls[i] = typecheck.Stmt(target.Decls[i])
134 // Don't use range--typecheck can add closures to Target.Decls.
135 for i := 0; i < len(target.Decls); i++ {
136 if fn, ok := target.Decls[i].(*ir.Func); ok {
138 s := fmt.Sprintf("\nbefore typecheck %v", fn)
142 typecheck.Stmts(fn.Body)
144 s := fmt.Sprintf("\nafter typecheck %v", fn)
150 base.ExitIfErrors() // just in case
153 // writePkgStub type checks the given parsed source files,
154 // writes an export data package stub representing them,
155 // and returns the result.
156 func writePkgStub(noders []*noder) string {
157 m, pkg, info := checkFiles(noders)
159 pw := newPkgWriter(m, pkg, info)
161 pw.collectDecls(noders)
163 publicRootWriter := pw.newWriter(relocMeta, syncPublic)
164 privateRootWriter := pw.newWriter(relocMeta, syncPrivate)
166 assert(publicRootWriter.idx == publicRootIdx)
167 assert(privateRootWriter.idx == privateRootIdx)
170 w := publicRootWriter
172 w.bool(false) // has init; XXX
175 names := scope.Names()
177 for _, name := range scope.Names() {
178 w.obj(scope.Lookup(name), nil)
186 w := privateRootWriter
192 var sb bytes.Buffer // TODO(mdempsky): strings.Builder after #44505 is resolved
195 // At this point, we're done with types2. Make sure the package is
196 // garbage collected.
202 // freePackage ensures the given package is garbage collected.
203 func freePackage(pkg *types2.Package) {
204 // The GC test below relies on a precise GC that runs finalizers as
205 // soon as objects are unreachable. Our implementation provides
206 // this, but other/older implementations may not (e.g., Go 1.4 does
207 // not because of #22350). To avoid imposing unnecessary
208 // restrictions on the GOROOT_BOOTSTRAP toolchain, we skip the test
209 // during bootstrapping.
210 if base.CompilerBootstrap {
214 // Set a finalizer on pkg so we can detect if/when it's collected.
215 done := make(chan struct{})
216 runtime.SetFinalizer(pkg, func(*types2.Package) { close(done) })
218 // Important: objects involved in cycles are not finalized, so zero
219 // out pkg to break its cycles and allow the finalizer to run.
220 *pkg = types2.Package{}
222 // It typically takes just 1 or 2 cycles to release pkg, but it
223 // doesn't hurt to try a few more times.
224 for i := 0; i < 10; i++ {
233 base.Fatalf("package never finalized")
236 func readPackage(pr *pkgReader, importpkg *types.Pkg) {
237 r := pr.newReader(relocMeta, publicRootIdx, syncPublic)
240 assert(pkg == importpkg)
243 sym := pkg.Lookup(".inittask")
244 task := ir.NewNameAt(src.NoXPos, sym)
245 task.Class = ir.PEXTERN
249 for i, n := 0, r.len(); i < n; i++ {
251 idx := r.reloc(relocObj)
254 path, name, code, _ := r.p.peekObj(idx)
256 objReader[types.NewPkg(path, "").Lookup(name)] = pkgReaderIndex{pr, idx, nil}
261 func writeNewExport(out io.Writer) {
265 pkgs: make(map[string]int),
266 decls: make(map[*types.Sym]int),
269 publicRootWriter := l.pw.newEncoder(relocMeta, syncPublic)
270 assert(publicRootWriter.idx == publicRootIdx)
276 r := pr.newDecoder(relocMeta, publicRootIdx, syncPublic)
279 selfPkgIdx = l.relocIdx(pr, relocPkg, r.reloc(relocPkg))
283 for i, n := 0, r.len(); i < n; i++ {
285 idx := r.reloc(relocObj)
288 xpath, xname, xtag, _ := pr.peekObj(idx)
289 assert(xpath == pr.pkgPath)
290 assert(xtag != objStub)
292 if types.IsExported(xname) {
293 l.relocIdx(pr, relocObj, idx)
302 for _, idx := range l.decls {
303 idxs = append(idxs, idx)
307 w := publicRootWriter
310 w.reloc(relocPkg, selfPkgIdx)
312 w.bool(typecheck.Lookup(".inittask").Def != nil)
315 for _, idx := range idxs {
317 w.reloc(relocObj, idx)