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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 13:16:40 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 13:16:40 +0000
commit47ab3d4a42e9ab51c465c4322d2ec233f6324e6b (patch)
treea61a0ffd83f4a3def4b36e5c8e99630c559aa723 /src/cmd/compile/internal/noder/linker.go
parentInitial commit. (diff)
downloadgolang-1.18-upstream.tar.xz
golang-1.18-upstream.zip
Adding upstream version 1.18.10.upstream/1.18.10upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/cmd/compile/internal/noder/linker.go')
-rw-r--r--src/cmd/compile/internal/noder/linker.go296
1 files changed, 296 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/noder/linker.go b/src/cmd/compile/internal/noder/linker.go
new file mode 100644
index 0000000..2bc7f7c
--- /dev/null
+++ b/src/cmd/compile/internal/noder/linker.go
@@ -0,0 +1,296 @@
+// UNREVIEWED
+
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package noder
+
+import (
+ "io"
+
+ "cmd/compile/internal/base"
+ "cmd/compile/internal/ir"
+ "cmd/compile/internal/reflectdata"
+ "cmd/compile/internal/types"
+ "cmd/internal/goobj"
+ "cmd/internal/obj"
+)
+
+// This file implements the unified IR linker, which combines the
+// local package's stub data with imported package data to produce a
+// complete export data file. It also rewrites the compiler's
+// extension data sections based on the results of compilation (e.g.,
+// the function inlining cost and linker symbol index assignments).
+//
+// TODO(mdempsky): Using the name "linker" here is confusing, because
+// readers are likely to mistake references to it for cmd/link. But
+// there's a shortage of good names for "something that combines
+// multiple parts into a cohesive whole"... e.g., "assembler" and
+// "compiler" are also already taken.
+
+type linker struct {
+ pw pkgEncoder
+
+ pkgs map[string]int
+ decls map[*types.Sym]int
+}
+
+func (l *linker) relocAll(pr *pkgReader, relocs []relocEnt) []relocEnt {
+ res := make([]relocEnt, len(relocs))
+ for i, rent := range relocs {
+ rent.idx = l.relocIdx(pr, rent.kind, rent.idx)
+ res[i] = rent
+ }
+ return res
+}
+
+func (l *linker) relocIdx(pr *pkgReader, k reloc, idx int) int {
+ assert(pr != nil)
+
+ absIdx := pr.absIdx(k, idx)
+
+ if newidx := pr.newindex[absIdx]; newidx != 0 {
+ return ^newidx
+ }
+
+ var newidx int
+ switch k {
+ case relocString:
+ newidx = l.relocString(pr, idx)
+ case relocPkg:
+ newidx = l.relocPkg(pr, idx)
+ case relocObj:
+ newidx = l.relocObj(pr, idx)
+
+ default:
+ // Generic relocations.
+ //
+ // TODO(mdempsky): Deduplicate more sections? In fact, I think
+ // every section could be deduplicated. This would also be easier
+ // if we do external relocations.
+
+ w := l.pw.newEncoderRaw(k)
+ l.relocCommon(pr, &w, k, idx)
+ newidx = w.idx
+ }
+
+ pr.newindex[absIdx] = ^newidx
+
+ return newidx
+}
+
+func (l *linker) relocString(pr *pkgReader, idx int) int {
+ return l.pw.stringIdx(pr.stringIdx(idx))
+}
+
+func (l *linker) relocPkg(pr *pkgReader, idx int) int {
+ path := pr.peekPkgPath(idx)
+
+ if newidx, ok := l.pkgs[path]; ok {
+ return newidx
+ }
+
+ r := pr.newDecoder(relocPkg, idx, syncPkgDef)
+ w := l.pw.newEncoder(relocPkg, syncPkgDef)
+ l.pkgs[path] = w.idx
+
+ // TODO(mdempsky): We end up leaving an empty string reference here
+ // from when the package was originally written as "". Probably not
+ // a big deal, but a little annoying. Maybe relocating
+ // cross-references in place is the way to go after all.
+ w.relocs = l.relocAll(pr, r.relocs)
+
+ _ = r.string() // original path
+ w.string(path)
+
+ io.Copy(&w.data, &r.data)
+
+ return w.flush()
+}
+
+func (l *linker) relocObj(pr *pkgReader, idx int) int {
+ path, name, tag := pr.peekObj(idx)
+ sym := types.NewPkg(path, "").Lookup(name)
+
+ if newidx, ok := l.decls[sym]; ok {
+ return newidx
+ }
+
+ if tag == objStub && path != "builtin" && path != "unsafe" {
+ pri, ok := objReader[sym]
+ if !ok {
+ base.Fatalf("missing reader for %q.%v", path, name)
+ }
+ assert(ok)
+
+ pr = pri.pr
+ idx = pri.idx
+
+ path2, name2, tag2 := pr.peekObj(idx)
+ sym2 := types.NewPkg(path2, "").Lookup(name2)
+ assert(sym == sym2)
+ assert(tag2 != objStub)
+ }
+
+ w := l.pw.newEncoderRaw(relocObj)
+ wext := l.pw.newEncoderRaw(relocObjExt)
+ wname := l.pw.newEncoderRaw(relocName)
+ wdict := l.pw.newEncoderRaw(relocObjDict)
+
+ l.decls[sym] = w.idx
+ assert(wext.idx == w.idx)
+ assert(wname.idx == w.idx)
+ assert(wdict.idx == w.idx)
+
+ l.relocCommon(pr, &w, relocObj, idx)
+ l.relocCommon(pr, &wname, relocName, idx)
+ l.relocCommon(pr, &wdict, relocObjDict, idx)
+
+ var obj *ir.Name
+ if path == "" {
+ var ok bool
+ obj, ok = sym.Def.(*ir.Name)
+
+ // Generic types and functions and declared constraint types won't
+ // have definitions.
+ // For now, just generically copy their extension data.
+ // TODO(mdempsky): Restore assertion.
+ if !ok && false {
+ base.Fatalf("missing definition for %v", sym)
+ }
+ }
+
+ if obj != nil {
+ wext.sync(syncObject1)
+ switch tag {
+ case objFunc:
+ l.relocFuncExt(&wext, obj)
+ case objType:
+ l.relocTypeExt(&wext, obj)
+ case objVar:
+ l.relocVarExt(&wext, obj)
+ }
+ wext.flush()
+ } else {
+ l.relocCommon(pr, &wext, relocObjExt, idx)
+ }
+
+ return w.idx
+}
+
+func (l *linker) relocCommon(pr *pkgReader, w *encoder, k reloc, idx int) {
+ r := pr.newDecoderRaw(k, idx)
+ w.relocs = l.relocAll(pr, r.relocs)
+ io.Copy(&w.data, &r.data)
+ w.flush()
+}
+
+func (l *linker) pragmaFlag(w *encoder, pragma ir.PragmaFlag) {
+ w.sync(syncPragma)
+ w.int(int(pragma))
+}
+
+func (l *linker) relocFuncExt(w *encoder, name *ir.Name) {
+ w.sync(syncFuncExt)
+
+ l.pragmaFlag(w, name.Func.Pragma)
+ l.linkname(w, name)
+
+ // Relocated extension data.
+ w.bool(true)
+
+ // Record definition ABI so cross-ABI calls can be direct.
+ // This is important for the performance of calling some
+ // common functions implemented in assembly (e.g., bytealg).
+ w.uint64(uint64(name.Func.ABI))
+
+ // Escape analysis.
+ for _, fs := range &types.RecvsParams {
+ for _, f := range fs(name.Type()).FieldSlice() {
+ w.string(f.Note)
+ }
+ }
+
+ if inl := name.Func.Inl; w.bool(inl != nil) {
+ w.len(int(inl.Cost))
+ w.bool(inl.CanDelayResults)
+
+ pri, ok := bodyReader[name.Func]
+ assert(ok)
+ w.reloc(relocBody, l.relocIdx(pri.pr, relocBody, pri.idx))
+ }
+
+ w.sync(syncEOF)
+}
+
+func (l *linker) relocTypeExt(w *encoder, name *ir.Name) {
+ w.sync(syncTypeExt)
+
+ typ := name.Type()
+
+ l.pragmaFlag(w, name.Pragma())
+
+ // For type T, export the index of type descriptor symbols of T and *T.
+ l.lsymIdx(w, "", reflectdata.TypeLinksym(typ))
+ l.lsymIdx(w, "", reflectdata.TypeLinksym(typ.PtrTo()))
+
+ if typ.Kind() != types.TINTER {
+ for _, method := range typ.Methods().Slice() {
+ l.relocFuncExt(w, method.Nname.(*ir.Name))
+ }
+ }
+}
+
+func (l *linker) relocVarExt(w *encoder, name *ir.Name) {
+ w.sync(syncVarExt)
+ l.linkname(w, name)
+}
+
+func (l *linker) linkname(w *encoder, name *ir.Name) {
+ w.sync(syncLinkname)
+
+ linkname := name.Sym().Linkname
+ if !l.lsymIdx(w, linkname, name.Linksym()) {
+ w.string(linkname)
+ }
+}
+
+func (l *linker) lsymIdx(w *encoder, linkname string, lsym *obj.LSym) bool {
+ if lsym.PkgIdx > goobj.PkgIdxSelf || (lsym.PkgIdx == goobj.PkgIdxInvalid && !lsym.Indexed()) || linkname != "" {
+ w.int64(-1)
+ return false
+ }
+
+ // For a defined symbol, export its index.
+ // For re-exporting an imported symbol, pass its index through.
+ w.int64(int64(lsym.SymIdx))
+ return true
+}
+
+// @@@ Helpers
+
+// TODO(mdempsky): These should probably be removed. I think they're a
+// smell that the export data format is not yet quite right.
+
+func (pr *pkgDecoder) peekPkgPath(idx int) string {
+ r := pr.newDecoder(relocPkg, idx, syncPkgDef)
+ path := r.string()
+ if path == "" {
+ path = pr.pkgPath
+ }
+ return path
+}
+
+func (pr *pkgDecoder) peekObj(idx int) (string, string, codeObj) {
+ r := pr.newDecoder(relocName, idx, syncObject1)
+ r.sync(syncSym)
+ r.sync(syncPkg)
+ path := pr.peekPkgPath(r.reloc(relocPkg))
+ name := r.string()
+ assert(name != "")
+
+ tag := codeObj(r.code(syncCodeObj))
+
+ return path, name, tag
+}