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
75 writeNewExportFunc = writeNewExport
77 newReadImportFunc = func(data string, pkg1 *types.Pkg, ctxt *types2.Context, packages map[string]*types2.Package) (pkg2 *types2.Package, err error) {
78 pr := newPkgDecoder(pkg1.Path, data)
80 // Read package descriptors for both types2 and compiler backend.
81 readPackage(newPkgReader(pr), pkg1)
82 pkg2 = readPackage2(ctxt, packages, pr)
86 data := writePkgStub(noders)
88 // We already passed base.Flag.Lang to types2 to handle validating
89 // the user's source code. Bump it up now to the current version and
90 // re-parse, so typecheck doesn't complain if we construct IR that
91 // utilizes newer Go features.
92 base.Flag.Lang = fmt.Sprintf("go1.%d", goversion.Version)
95 assert(types.LocalPkg.Path == "")
96 types.LocalPkg.Height = 0 // reset so pkgReader.pkgIdx doesn't complain
97 target := typecheck.Target
99 typecheck.TypecheckAllowed = true
101 localPkgReader = newPkgReader(newPkgDecoder(types.LocalPkg.Path, data))
102 readPackage(localPkgReader, types.LocalPkg)
104 r := localPkgReader.newReader(relocMeta, privateRootIdx, syncPrivate)
105 r.pkgInit(types.LocalPkg, target)
107 // Type-check any top-level assignments. We ignore non-assignments
108 // here because other declarations are typechecked as they're
110 for i, ndecls := 0, len(target.Decls); i < ndecls; i++ {
111 switch n := target.Decls[i]; n.Op() {
112 case ir.OAS, ir.OAS2:
113 target.Decls[i] = typecheck.Stmt(n)
117 // Don't use range--bodyIdx can add closures to todoBodies.
118 for len(todoBodies) > 0 {
119 // The order we expand bodies doesn't matter, so pop from the end
120 // to reduce todoBodies reallocations if it grows further.
121 fn := todoBodies[len(todoBodies)-1]
122 todoBodies = todoBodies[:len(todoBodies)-1]
124 pri, ok := bodyReader[fn]
128 // Instantiated generic function: add to Decls for typechecking
130 if fn.OClosure == nil && len(pri.dict.targs) != 0 {
131 target.Decls = append(target.Decls, fn)
135 todoBodiesDone = true
137 // Check that nothing snuck past typechecking.
138 for _, n := range target.Decls {
139 if n.Typecheck() == 0 {
140 base.FatalfAt(n.Pos(), "missed typecheck: %v", n)
143 // For functions, check that at least their first statement (if
144 // any) was typechecked too.
145 if fn, ok := n.(*ir.Func); ok && len(fn.Body) != 0 {
146 if stmt := fn.Body[0]; stmt.Typecheck() == 0 {
147 base.FatalfAt(stmt.Pos(), "missed typecheck: %v", stmt)
152 base.ExitIfErrors() // just in case
155 // writePkgStub type checks the given parsed source files,
156 // writes an export data package stub representing them,
157 // and returns the result.
158 func writePkgStub(noders []*noder) string {
159 m, pkg, info := checkFiles(noders)
161 pw := newPkgWriter(m, pkg, info)
163 pw.collectDecls(noders)
165 publicRootWriter := pw.newWriter(relocMeta, syncPublic)
166 privateRootWriter := pw.newWriter(relocMeta, syncPrivate)
168 assert(publicRootWriter.idx == publicRootIdx)
169 assert(privateRootWriter.idx == privateRootIdx)
172 w := publicRootWriter
174 w.bool(false) // has init; XXX
177 names := scope.Names()
179 for _, name := range scope.Names() {
180 w.obj(scope.Lookup(name), nil)
188 w := privateRootWriter
193 var sb bytes.Buffer // TODO(mdempsky): strings.Builder after #44505 is resolved
196 // At this point, we're done with types2. Make sure the package is
197 // garbage collected.
203 // freePackage ensures the given package is garbage collected.
204 func freePackage(pkg *types2.Package) {
205 // The GC test below relies on a precise GC that runs finalizers as
206 // soon as objects are unreachable. Our implementation provides
207 // this, but other/older implementations may not (e.g., Go 1.4 does
208 // not because of #22350). To avoid imposing unnecessary
209 // restrictions on the GOROOT_BOOTSTRAP toolchain, we skip the test
210 // during bootstrapping.
211 if base.CompilerBootstrap {
215 // Set a finalizer on pkg so we can detect if/when it's collected.
216 done := make(chan struct{})
217 runtime.SetFinalizer(pkg, func(*types2.Package) { close(done) })
219 // Important: objects involved in cycles are not finalized, so zero
220 // out pkg to break its cycles and allow the finalizer to run.
221 *pkg = types2.Package{}
223 // It typically takes just 1 or 2 cycles to release pkg, but it
224 // doesn't hurt to try a few more times.
225 for i := 0; i < 10; i++ {
234 base.Fatalf("package never finalized")
237 func readPackage(pr *pkgReader, importpkg *types.Pkg) {
238 r := pr.newReader(relocMeta, publicRootIdx, syncPublic)
241 assert(pkg == importpkg)
244 sym := pkg.Lookup(".inittask")
245 task := ir.NewNameAt(src.NoXPos, sym)
246 task.Class = ir.PEXTERN
250 for i, n := 0, r.len(); i < n; i++ {
253 idx := r.reloc(relocObj)
256 path, name, code := r.p.peekObj(idx)
258 objReader[types.NewPkg(path, "").Lookup(name)] = pkgReaderIndex{pr, idx, nil}
263 func writeNewExport(out io.Writer) {
267 pkgs: make(map[string]int),
268 decls: make(map[*types.Sym]int),
271 publicRootWriter := l.pw.newEncoder(relocMeta, syncPublic)
272 assert(publicRootWriter.idx == publicRootIdx)
278 r := pr.newDecoder(relocMeta, publicRootIdx, syncPublic)
281 selfPkgIdx = l.relocIdx(pr, relocPkg, r.reloc(relocPkg))
285 for i, n := 0, r.len(); i < n; i++ {
288 idx := r.reloc(relocObj)
291 xpath, xname, xtag := pr.peekObj(idx)
292 assert(xpath == pr.pkgPath)
293 assert(xtag != objStub)
295 if types.IsExported(xname) {
296 l.relocIdx(pr, relocObj, idx)
305 for _, idx := range l.decls {
306 idxs = append(idxs, idx)
310 w := publicRootWriter
313 w.reloc(relocPkg, selfPkgIdx)
315 w.bool(typecheck.Lookup(".inittask").Def != nil)
318 for _, idx := range idxs {
321 w.reloc(relocObj, idx)