2 files changed, 520 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/staticdata/data.go b/src/cmd/compile/internal/staticdata/data.go
new file mode 100644
index 0000000..78c332e
--- /dev/null
+++ b/src/cmd/compile/internal/staticdata/data.go
@@ -0,0 +1,346 @@
+// Copyright 2009 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 staticdata
+
+import (
+	"encoding/base64"
+	"fmt"
+	"go/constant"
+	"io"
+	"os"
+	"sort"
+	"strconv"
+	"sync"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/objw"
+	"cmd/compile/internal/types"
+	"cmd/internal/notsha256"
+	"cmd/internal/obj"
+	"cmd/internal/objabi"
+	"cmd/internal/src"
+)
+
+// InitAddrOffset writes the static name symbol lsym to n, it does not modify n.
+// It's the caller responsibility to make sure lsym is from ONAME/PEXTERN node.
+func InitAddrOffset(n *ir.Name, noff int64, lsym *obj.LSym, off int64) {
+	if n.Op() != ir.ONAME {
+		base.Fatalf("InitAddr n op %v", n.Op())
+	}
+	if n.Sym() == nil {
+		base.Fatalf("InitAddr nil n sym")
+	}
+	s := n.Linksym()
+	s.WriteAddr(base.Ctxt, noff, types.PtrSize, lsym, off)
+}
+
+// InitAddr is InitAddrOffset, with offset fixed to 0.
+func InitAddr(n *ir.Name, noff int64, lsym *obj.LSym) {
+	InitAddrOffset(n, noff, lsym, 0)
+}
+
+// InitSlice writes a static slice symbol {lsym, lencap, lencap} to n+noff, it does not modify n.
+// It's the caller responsibility to make sure lsym is from ONAME node.
+func InitSlice(n *ir.Name, noff int64, lsym *obj.LSym, lencap int64) {
+	s := n.Linksym()
+	s.WriteAddr(base.Ctxt, noff, types.PtrSize, lsym, 0)
+	s.WriteInt(base.Ctxt, noff+types.SliceLenOffset, types.PtrSize, lencap)
+	s.WriteInt(base.Ctxt, noff+types.SliceCapOffset, types.PtrSize, lencap)
+}
+
+func InitSliceBytes(nam *ir.Name, off int64, s string) {
+	if nam.Op() != ir.ONAME {
+		base.Fatalf("InitSliceBytes %v", nam)
+	}
+	InitSlice(nam, off, slicedata(nam.Pos(), s), int64(len(s)))
+}
+
+const (
+	stringSymPrefix  = "go:string."
+	stringSymPattern = ".gostring.%d.%s"
+)
+
+// shortHashString converts the hash to a string for use with stringSymPattern.
+// We cut it to 16 bytes and then base64-encode to make it even smaller.
+func shortHashString(hash []byte) string {
+	return base64.StdEncoding.EncodeToString(hash[:16])
+}
+
+// StringSym returns a symbol containing the string s.
+// The symbol contains the string data, not a string header.
+func StringSym(pos src.XPos, s string) (data *obj.LSym) {
+	var symname string
+	if len(s) > 100 {
+		// Huge strings are hashed to avoid long names in object files.
+		// Indulge in some paranoia by writing the length of s, too,
+		// as protection against length extension attacks.
+		// Same pattern is known to fileStringSym below.
+		h := notsha256.New()
+		io.WriteString(h, s)
+		symname = fmt.Sprintf(stringSymPattern, len(s), shortHashString(h.Sum(nil)))
+	} else {
+		// Small strings get named directly by their contents.
+		symname = strconv.Quote(s)
+	}
+
+	symdata := base.Ctxt.Lookup(stringSymPrefix + symname)
+	if !symdata.OnList() {
+		off := dstringdata(symdata, 0, s, pos, "string")
+		objw.Global(symdata, int32(off), obj.DUPOK|obj.RODATA|obj.LOCAL)
+		symdata.Set(obj.AttrContentAddressable, true)
+	}
+
+	return symdata
+}
+
+// StringSymNoCommon is like StringSym, but produces a symbol that is not content-
+// addressable. This symbol is not supposed to appear in the final binary, it is
+// only used to pass string arguments to the linker like R_USENAMEDMETHOD does.
+func StringSymNoCommon(s string) (data *obj.LSym) {
+	var nameSym obj.LSym
+	nameSym.WriteString(base.Ctxt, 0, len(s), s)
+	objw.Global(&nameSym, int32(len(s)), obj.RODATA)
+	return &nameSym
+}
+
+// maxFileSize is the maximum file size permitted by the linker
+// (see issue #9862).
+const maxFileSize = int64(2e9)
+
+// fileStringSym returns a symbol for the contents and the size of file.
+// If readonly is true, the symbol shares storage with any literal string
+// or other file with the same content and is placed in a read-only section.
+// If readonly is false, the symbol is a read-write copy separate from any other,
+// for use as the backing store of a []byte.
+// The content hash of file is copied into hash. (If hash is nil, nothing is copied.)
+// The returned symbol contains the data itself, not a string header.
+func fileStringSym(pos src.XPos, file string, readonly bool, hash []byte) (*obj.LSym, int64, error) {
+	f, err := os.Open(file)
+	if err != nil {
+		return nil, 0, err
+	}
+	defer f.Close()
+	info, err := f.Stat()
+	if err != nil {
+		return nil, 0, err
+	}
+	if !info.Mode().IsRegular() {
+		return nil, 0, fmt.Errorf("not a regular file")
+	}
+	size := info.Size()
+	if size <= 1*1024 {
+		data, err := io.ReadAll(f)
+		if err != nil {
+			return nil, 0, err
+		}
+		if int64(len(data)) != size {
+			return nil, 0, fmt.Errorf("file changed between reads")
+		}
+		var sym *obj.LSym
+		if readonly {
+			sym = StringSym(pos, string(data))
+		} else {
+			sym = slicedata(pos, string(data))
+		}
+		if len(hash) > 0 {
+			sum := notsha256.Sum256(data)
+			copy(hash, sum[:])
+		}
+		return sym, size, nil
+	}
+	if size > maxFileSize {
+		// ggloblsym takes an int32,
+		// and probably the rest of the toolchain
+		// can't handle such big symbols either.
+		// See golang.org/issue/9862.
+		return nil, 0, fmt.Errorf("file too large (%d bytes > %d bytes)", size, maxFileSize)
+	}
+
+	// File is too big to read and keep in memory.
+	// Compute hash if needed for read-only content hashing or if the caller wants it.
+	var sum []byte
+	if readonly || len(hash) > 0 {
+		h := notsha256.New()
+		n, err := io.Copy(h, f)
+		if err != nil {
+			return nil, 0, err
+		}
+		if n != size {
+			return nil, 0, fmt.Errorf("file changed between reads")
+		}
+		sum = h.Sum(nil)
+		copy(hash, sum)
+	}
+
+	var symdata *obj.LSym
+	if readonly {
+		symname := fmt.Sprintf(stringSymPattern, size, shortHashString(sum))
+		symdata = base.Ctxt.Lookup(stringSymPrefix + symname)
+		if !symdata.OnList() {
+			info := symdata.NewFileInfo()
+			info.Name = file
+			info.Size = size
+			objw.Global(symdata, int32(size), obj.DUPOK|obj.RODATA|obj.LOCAL)
+			// Note: AttrContentAddressable cannot be set here,
+			// because the content-addressable-handling code
+			// does not know about file symbols.
+		}
+	} else {
+		// Emit a zero-length data symbol
+		// and then fix up length and content to use file.
+		symdata = slicedata(pos, "")
+		symdata.Size = size
+		symdata.Type = objabi.SNOPTRDATA
+		info := symdata.NewFileInfo()
+		info.Name = file
+		info.Size = size
+	}
+
+	return symdata, size, nil
+}
+
+var slicedataGen int
+
+func slicedata(pos src.XPos, s string) *obj.LSym {
+	slicedataGen++
+	symname := fmt.Sprintf(".gobytes.%d", slicedataGen)
+	lsym := types.LocalPkg.Lookup(symname).LinksymABI(obj.ABI0)
+	off := dstringdata(lsym, 0, s, pos, "slice")
+	objw.Global(lsym, int32(off), obj.NOPTR|obj.LOCAL)
+
+	return lsym
+}
+
+func dstringdata(s *obj.LSym, off int, t string, pos src.XPos, what string) int {
+	// Objects that are too large will cause the data section to overflow right away,
+	// causing a cryptic error message by the linker. Check for oversize objects here
+	// and provide a useful error message instead.
+	if int64(len(t)) > 2e9 {
+		base.ErrorfAt(pos, 0, "%v with length %v is too big", what, len(t))
+		return 0
+	}
+
+	s.WriteString(base.Ctxt, int64(off), len(t), t)
+	return off + len(t)
+}
+
+var (
+	funcsymsmu sync.Mutex // protects funcsyms and associated package lookups (see func funcsym)
+	funcsyms   []*ir.Name // functions that need function value symbols
+)
+
+// FuncLinksym returns n·f, the function value symbol for n.
+func FuncLinksym(n *ir.Name) *obj.LSym {
+	if n.Op() != ir.ONAME || n.Class != ir.PFUNC {
+		base.Fatalf("expected func name: %v", n)
+	}
+	s := n.Sym()
+
+	// funcsymsmu here serves to protect not just mutations of funcsyms (below),
+	// but also the package lookup of the func sym name,
+	// since this function gets called concurrently from the backend.
+	// There are no other concurrent package lookups in the backend,
+	// except for the types package, which is protected separately.
+	// Reusing funcsymsmu to also cover this package lookup
+	// avoids a general, broader, expensive package lookup mutex.
+	funcsymsmu.Lock()
+	sf, existed := s.Pkg.LookupOK(ir.FuncSymName(s))
+	if !existed {
+		funcsyms = append(funcsyms, n)
+	}
+	funcsymsmu.Unlock()
+
+	return sf.Linksym()
+}
+
+func GlobalLinksym(n *ir.Name) *obj.LSym {
+	if n.Op() != ir.ONAME || n.Class != ir.PEXTERN {
+		base.Fatalf("expected global variable: %v", n)
+	}
+	return n.Linksym()
+}
+
+func WriteFuncSyms() {
+	sort.Slice(funcsyms, func(i, j int) bool {
+		return funcsyms[i].Linksym().Name < funcsyms[j].Linksym().Name
+	})
+	for _, nam := range funcsyms {
+		s := nam.Sym()
+		sf := s.Pkg.Lookup(ir.FuncSymName(s)).Linksym()
+
+		// While compiling package runtime, we might try to create
+		// funcsyms for functions from both types.LocalPkg and
+		// ir.Pkgs.Runtime.
+		if base.Flag.CompilingRuntime && sf.OnList() {
+			continue
+		}
+
+		// Function values must always reference ABIInternal
+		// entry points.
+		target := s.Linksym()
+		if target.ABI() != obj.ABIInternal {
+			base.Fatalf("expected ABIInternal: %v has %v", target, target.ABI())
+		}
+		objw.SymPtr(sf, 0, target, 0)
+		objw.Global(sf, int32(types.PtrSize), obj.DUPOK|obj.RODATA)
+	}
+}
+
+// InitConst writes the static literal c to n.
+// Neither n nor c is modified.
+func InitConst(n *ir.Name, noff int64, c ir.Node, wid int) {
+	if n.Op() != ir.ONAME {
+		base.Fatalf("InitConst n op %v", n.Op())
+	}
+	if n.Sym() == nil {
+		base.Fatalf("InitConst nil n sym")
+	}
+	if c.Op() == ir.ONIL {
+		return
+	}
+	if c.Op() != ir.OLITERAL {
+		base.Fatalf("InitConst c op %v", c.Op())
+	}
+	s := n.Linksym()
+	switch u := c.Val(); u.Kind() {
+	case constant.Bool:
+		i := int64(obj.Bool2int(constant.BoolVal(u)))
+		s.WriteInt(base.Ctxt, noff, wid, i)
+
+	case constant.Int:
+		s.WriteInt(base.Ctxt, noff, wid, ir.IntVal(c.Type(), u))
+
+	case constant.Float:
+		f, _ := constant.Float64Val(u)
+		switch c.Type().Kind() {
+		case types.TFLOAT32:
+			s.WriteFloat32(base.Ctxt, noff, float32(f))
+		case types.TFLOAT64:
+			s.WriteFloat64(base.Ctxt, noff, f)
+		}
+
+	case constant.Complex:
+		re, _ := constant.Float64Val(constant.Real(u))
+		im, _ := constant.Float64Val(constant.Imag(u))
+		switch c.Type().Kind() {
+		case types.TCOMPLEX64:
+			s.WriteFloat32(base.Ctxt, noff, float32(re))
+			s.WriteFloat32(base.Ctxt, noff+4, float32(im))
+		case types.TCOMPLEX128:
+			s.WriteFloat64(base.Ctxt, noff, re)
+			s.WriteFloat64(base.Ctxt, noff+8, im)
+		}
+
+	case constant.String:
+		i := constant.StringVal(u)
+		symdata := StringSym(n.Pos(), i)
+		s.WriteAddr(base.Ctxt, noff, types.PtrSize, symdata, 0)
+		s.WriteInt(base.Ctxt, noff+int64(types.PtrSize), types.PtrSize, int64(len(i)))
+
+	default:
+		base.Fatalf("InitConst unhandled OLITERAL %v", c)
+	}
+}
diff --git a/src/cmd/compile/internal/staticdata/embed.go b/src/cmd/compile/internal/staticdata/embed.go
new file mode 100644
index 0000000..a4d493c
--- /dev/null
+++ b/src/cmd/compile/internal/staticdata/embed.go
@@ -0,0 +1,174 @@
+// Copyright 2020 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 staticdata
+
+import (
+	"path"
+	"sort"
+	"strings"
+
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/objw"
+	"cmd/compile/internal/types"
+	"cmd/internal/obj"
+)
+
+const (
+	embedUnknown = iota
+	embedBytes
+	embedString
+	embedFiles
+)
+
+func embedFileList(v *ir.Name, kind int) []string {
+	// Build list of files to store.
+	have := make(map[string]bool)
+	var list []string
+	for _, e := range *v.Embed {
+		for _, pattern := range e.Patterns {
+			files, ok := base.Flag.Cfg.Embed.Patterns[pattern]
+			if !ok {
+				base.ErrorfAt(e.Pos, 0, "invalid go:embed: build system did not map pattern: %s", pattern)
+			}
+			for _, file := range files {
+				if base.Flag.Cfg.Embed.Files[file] == "" {
+					base.ErrorfAt(e.Pos, 0, "invalid go:embed: build system did not map file: %s", file)
+					continue
+				}
+				if !have[file] {
+					have[file] = true
+					list = append(list, file)
+				}
+				if kind == embedFiles {
+					for dir := path.Dir(file); dir != "." && !have[dir]; dir = path.Dir(dir) {
+						have[dir] = true
+						list = append(list, dir+"/")
+					}
+				}
+			}
+		}
+	}
+	sort.Slice(list, func(i, j int) bool {
+		return embedFileLess(list[i], list[j])
+	})
+
+	if kind == embedString || kind == embedBytes {
+		if len(list) > 1 {
+			base.ErrorfAt(v.Pos(), 0, "invalid go:embed: multiple files for type %v", v.Type())
+			return nil
+		}
+	}
+
+	return list
+}
+
+// embedKind determines the kind of embedding variable.
+func embedKind(typ *types.Type) int {
+	if typ.Sym() != nil && typ.Sym().Name == "FS" && typ.Sym().Pkg.Path == "embed" {
+		return embedFiles
+	}
+	if typ.Kind() == types.TSTRING {
+		return embedString
+	}
+	if typ.IsSlice() && typ.Elem().Kind() == types.TUINT8 {
+		return embedBytes
+	}
+	return embedUnknown
+}
+
+func embedFileNameSplit(name string) (dir, elem string, isDir bool) {
+	if name[len(name)-1] == '/' {
+		isDir = true
+		name = name[:len(name)-1]
+	}
+	i := len(name) - 1
+	for i >= 0 && name[i] != '/' {
+		i--
+	}
+	if i < 0 {
+		return ".", name, isDir
+	}
+	return name[:i], name[i+1:], isDir
+}
+
+// embedFileLess implements the sort order for a list of embedded files.
+// See the comment inside ../../../../embed/embed.go's Files struct for rationale.
+func embedFileLess(x, y string) bool {
+	xdir, xelem, _ := embedFileNameSplit(x)
+	ydir, yelem, _ := embedFileNameSplit(y)
+	return xdir < ydir || xdir == ydir && xelem < yelem
+}
+
+// WriteEmbed emits the init data for a //go:embed variable,
+// which is either a string, a []byte, or an embed.FS.
+func WriteEmbed(v *ir.Name) {
+	// TODO(mdempsky): User errors should be reported by the frontend.
+
+	commentPos := (*v.Embed)[0].Pos
+	if base.Flag.Cfg.Embed.Patterns == nil {
+		base.ErrorfAt(commentPos, 0, "invalid go:embed: build system did not supply embed configuration")
+		return
+	}
+	kind := embedKind(v.Type())
+	if kind == embedUnknown {
+		base.ErrorfAt(v.Pos(), 0, "go:embed cannot apply to var of type %v", v.Type())
+		return
+	}
+
+	files := embedFileList(v, kind)
+	switch kind {
+	case embedString, embedBytes:
+		file := files[0]
+		fsym, size, err := fileStringSym(v.Pos(), base.Flag.Cfg.Embed.Files[file], kind == embedString, nil)
+		if err != nil {
+			base.ErrorfAt(v.Pos(), 0, "embed %s: %v", file, err)
+		}
+		sym := v.Linksym()
+		off := 0
+		off = objw.SymPtr(sym, off, fsym, 0)       // data string
+		off = objw.Uintptr(sym, off, uint64(size)) // len
+		if kind == embedBytes {
+			objw.Uintptr(sym, off, uint64(size)) // cap for slice
+		}
+
+	case embedFiles:
+		slicedata := v.Sym().Pkg.Lookup(v.Sym().Name + `.files`).Linksym()
+		off := 0
+		// []files pointed at by Files
+		off = objw.SymPtr(slicedata, off, slicedata, 3*types.PtrSize) // []file, pointing just past slice
+		off = objw.Uintptr(slicedata, off, uint64(len(files)))
+		off = objw.Uintptr(slicedata, off, uint64(len(files)))
+
+		// embed/embed.go type file is:
+		//	name string
+		//	data string
+		//	hash [16]byte
+		// Emit one of these per file in the set.
+		const hashSize = 16
+		hash := make([]byte, hashSize)
+		for _, file := range files {
+			off = objw.SymPtr(slicedata, off, StringSym(v.Pos(), file), 0) // file string
+			off = objw.Uintptr(slicedata, off, uint64(len(file)))
+			if strings.HasSuffix(file, "/") {
+				// entry for directory - no data
+				off = objw.Uintptr(slicedata, off, 0)
+				off = objw.Uintptr(slicedata, off, 0)
+				off += hashSize
+			} else {
+				fsym, size, err := fileStringSym(v.Pos(), base.Flag.Cfg.Embed.Files[file], true, hash)
+				if err != nil {
+					base.ErrorfAt(v.Pos(), 0, "embed %s: %v", file, err)
+				}
+				off = objw.SymPtr(slicedata, off, fsym, 0) // data string
+				off = objw.Uintptr(slicedata, off, uint64(size))
+				off = int(slicedata.WriteBytes(base.Ctxt, int64(off), hash))
+			}
+		}
+		objw.Global(slicedata, int32(off), obj.RODATA|obj.LOCAL)
+		sym := v.Linksym()
+		objw.SymPtr(sym, 0, slicedata, 0)
+	}
+}