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[dev.link] cmd/link: elf host obj support w/ new obj files

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Add support for elf host objects with new object file format.

Change-Id: Ic5be1953359b9b6b78d9a0b715af69763aefd227
Reviewed-on: https://go-review.googlesource.com/c/go/+/201728
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
This commit is contained in:
Jeremy Faller 2019-10-17 11:06:11 -04:00
parent 5a210b5858
commit 0e76e2f4e5
6 changed files with 195 additions and 57 deletions
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52
src/cmd/link/internal/ld/lib.go
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@ -443,6 +443,10 @@ func (ctxt *Link) loadlib() {
}
}
// Conditionally load host objects, or setup for external linking.
hostobjs(ctxt)
hostlinksetup(ctxt)
if *flagNewobj {
// Add references of externally defined symbols.
ctxt.loader.LoadRefs(ctxt.Arch, ctxt.Syms)
@ -453,7 +457,6 @@ func (ctxt *Link) loadlib() {
setupdynexp(ctxt)
}
// In internal link mode, read the host object files.
if ctxt.LinkMode == LinkInternal && len(hostobj) != 0 {
// Drop all the cgo_import_static declarations.
// Turns out we won't be needing them.
@ -471,8 +474,6 @@ func (ctxt *Link) loadlib() {
}
}
hostobjs(ctxt)
// If we have any undefined symbols in external
// objects, try to read them from the libgcc file.
any := false
@ -520,8 +521,6 @@ func (ctxt *Link) loadlib() {
*/
}
}
} else if ctxt.LinkMode == LinkExternal {
hostlinksetup(ctxt)
}
// We've loaded all the code now.
@ -977,6 +976,9 @@ func ldhostobj(ld func(*Link, *bio.Reader, string, int64, string), headType obja
}
func hostobjs(ctxt *Link) {
if ctxt.LinkMode != LinkInternal {
return
}
var h *Hostobj
for i := 0; i < len(hostobj); i++ {
@ -1623,16 +1625,29 @@ func ldobj(ctxt *Link, f *bio.Reader, lib *sym.Library, length int64, pn string,
magic := uint32(c1)<<24 | uint32(c2)<<16 | uint32(c3)<<8 | uint32(c4)
if magic == 0x7f454c46 { // \x7F E L F
ldelf := func(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
textp, flags, err := loadelf.Load(ctxt.Arch, ctxt.Syms, f, pkg, length, pn, ehdr.flags)
if err != nil {
Errorf(nil, "%v", err)
return
if *flagNewobj {
ldelf := func(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
textp, flags, err := loadelf.Load(ctxt.loader, ctxt.Arch, ctxt.Syms, f, pkg, length, pn, ehdr.flags)
if err != nil {
Errorf(nil, "%v", err)
return
}
ehdr.flags = flags
ctxt.Textp = append(ctxt.Textp, textp...)
}
ehdr.flags = flags
ctxt.Textp = append(ctxt.Textp, textp...)
return ldhostobj(ldelf, ctxt.HeadType, f, pkg, length, pn, file)
} else {
ldelf := func(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
textp, flags, err := loadelf.LoadOld(ctxt.Arch, ctxt.Syms, f, pkg, length, pn, ehdr.flags)
if err != nil {
Errorf(nil, "%v", err)
return
}
ehdr.flags = flags
ctxt.Textp = append(ctxt.Textp, textp...)
}
return ldhostobj(ldelf, ctxt.HeadType, f, pkg, length, pn, file)
}
return ldhostobj(ldelf, ctxt.HeadType, f, pkg, length, pn, file)
}
if magic&^1 == 0xfeedface || magic&^0x01000000 == 0xcefaedfe {
@ -2379,6 +2394,9 @@ func genasmsym(ctxt *Link, put func(*Link, *sym.Symbol, string, SymbolType, int6
put(ctxt, s, s.Name, BSSSym, Symaddr(s), s.Gotype)
case sym.SHOSTOBJ:
if !s.Attr.Reachable() {
continue
}
if ctxt.HeadType == objabi.Hwindows || ctxt.IsELF {
put(ctxt, s, s.Name, UndefinedSym, s.Value, nil)
}
@ -2580,12 +2598,8 @@ func (ctxt *Link) loadlibfull() {
// Load full symbol contents, resolve indexed references.
ctxt.loader.LoadFull(ctxt.Arch, ctxt.Syms)
// For now, add all symbols to ctxt.Syms.
for _, s := range ctxt.loader.Syms {
if s != nil && s.Name != "" {
ctxt.Syms.Add(s)
}
}
// Pull the symbols out.
ctxt.loader.ExtractSymbols(ctxt.Syms)
// Load cgo directives.
for _, d := range ctxt.cgodata {