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cmd/6g: call duffcopy, duffzero via got when dynamically linking go

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Jumping to an offset past a symbol isn't something that is really
supported by dynamic linkers, so do it by hand.

Change-Id: Ifff8834c6cdfa3d521ebd8479d2e93906df9b258
Reviewed-on: https://go-review.googlesource.com/8238
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
Michael Hudson-Doyle 2015-03-30 01:54:49 +00:00 committed by Ian Lance Taylor
parent 8bf0ed5147
commit 1d1c61ba7d
2 changed files with 32 additions and 0 deletions
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4
src/cmd/internal/obj/x86/asm6.go
View File

@ -3450,6 +3450,10 @@ func doasm(ctxt *obj.Link, p *obj.Prog) {
log.Fatalf("bad code")
}
if yt.zcase == Zcallduff && ctxt.Flag_dynlink {
ctxt.Diag("directly calling duff when dynamically linking Go")
}
if obj.Framepointer_enabled != 0 && yt.zcase == Zcallduff && p.Mode == 64 {
// Maintain BP around call, since duffcopy/duffzero can't do it
// (the call jumps into the middle of the function).

28
src/cmd/internal/obj/x86/obj6.go
View File

@ -298,6 +298,34 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
}
}
if ctxt.Flag_dynlink && (p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO) {
var sym *obj.LSym
if p.As == obj.ADUFFZERO {
sym = obj.Linklookup(ctxt, "runtime.duffzero", 0)
} else {
sym = obj.Linklookup(ctxt, "runtime.duffcopy", 0)
}
offset := p.To.Offset
p.As = AMOVQ
p.From.Type = obj.TYPE_MEM
p.From.Name = obj.NAME_GOTREF
p.From.Sym = sym
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R15
p.To.Offset = 0
p.To.Sym = nil
p1 := obj.Appendp(ctxt, p)
p1.As = AADDQ
p1.From.Type = obj.TYPE_CONST
p1.From.Offset = offset
p1.To.Type = obj.TYPE_REG
p1.To.Reg = REG_R15
p2 := obj.Appendp(ctxt, p1)
p2.As = obj.ACALL
p2.To.Type = obj.TYPE_REG
p2.To.Reg = REG_R15
}
if ctxt.Flag_dynlink {
if p.As == ALEAQ && p.From.Type == obj.TYPE_MEM && p.From.Name == obj.NAME_EXTERN {
p.As = AMOVQ