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https://github.com/golang/go
synced 2024-11-17 22:54:48 -07:00
cmd/internal/obj/x86: factor rewriting to use GOT into separate function
I was prodded into doing this in review comments for the ARM version, and it's going to make shared libs for 386 easier. Change-Id: Id12de801b1425b8c6b5736fe91b418fc123a4e40 Reviewed-on: https://go-review.googlesource.com/17012 Reviewed-by: David Crawshaw <crawshaw@golang.org>
This commit is contained in:
Michael Hudson-Doyle
parent
6bf794a36d
commit
3c85e1b186
@ -2090,8 +2090,11 @@ func oclass(ctxt *obj.Link, p *obj.Prog, a *obj.Addr) int {
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case obj.TYPE_ADDR:
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switch a.Name {
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case obj.NAME_GOTREF:
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ctxt.Diag("unexpected TYPE_ADDR with NAME_GOTREF")
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return Yxxx
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case obj.NAME_EXTERN,
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obj.NAME_GOTREF,
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obj.NAME_STATIC:
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if a.Sym != nil && isextern(a.Sym) || p.Mode == 32 {
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return Yi32
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@ -308,7 +308,19 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
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}
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}
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if ctxt.Flag_dynlink && (p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO) {
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if ctxt.Flag_dynlink {
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rewriteToUseGot(ctxt, p)
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}
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}
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// Rewrite p, if necessary, to access global data via the global offset table.
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func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog) {
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if p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
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// ADUFFxxx $offset
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// becomes
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// MOVQ runtime.duffxxx@GOT, R15
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// ADDQ $offset, R15
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// CALL R15
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var sym *obj.LSym
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if p.As == obj.ADUFFZERO {
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sym = obj.Linklookup(ctxt, "runtime.duffzero", 0)
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@ -336,80 +348,82 @@ func progedit(ctxt *obj.Link, p *obj.Prog) {
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p2.To.Reg = REG_R15
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}
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if ctxt.Flag_dynlink {
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if p.As == ALEAQ && p.From.Type == obj.TYPE_MEM && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
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p.As = AMOVQ
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p.From.Type = obj.TYPE_ADDR
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}
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if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
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if p.As != AMOVQ {
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ctxt.Diag("do not know how to handle TYPE_ADDR in %v with -dynlink", p)
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}
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if p.To.Type != obj.TYPE_REG {
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ctxt.Diag("do not know how to handle LEAQ-type insn to non-register in %v with -dynlink", p)
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}
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p.From.Type = obj.TYPE_MEM
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p.From.Name = obj.NAME_GOTREF
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if p.From.Offset != 0 {
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q := obj.Appendp(ctxt, p)
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q.As = AADDQ
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q.From.Type = obj.TYPE_CONST
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q.From.Offset = p.From.Offset
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q.To = p.To
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p.From.Offset = 0
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}
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}
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if p.From3 != nil && p.From3.Name == obj.NAME_EXTERN {
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ctxt.Diag("don't know how to handle %v with -dynlink", p)
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}
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var source *obj.Addr
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if p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
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if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local {
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ctxt.Diag("cannot handle NAME_EXTERN on both sides in %v with -dynlink", p)
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}
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source = &p.From
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} else if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local {
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source = &p.To
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} else {
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return
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}
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if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ACALL || p.As == obj.ARET || p.As == obj.AJMP {
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return
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}
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if source.Type != obj.TYPE_MEM {
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ctxt.Diag("don't know how to handle %v with -dynlink", p)
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}
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p1 := obj.Appendp(ctxt, p)
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p2 := obj.Appendp(ctxt, p1)
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p1.As = AMOVQ
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p1.From.Type = obj.TYPE_MEM
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p1.From.Sym = source.Sym
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p1.From.Name = obj.NAME_GOTREF
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p1.To.Type = obj.TYPE_REG
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p1.To.Reg = REG_R15
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p2.As = p.As
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p2.From = p.From
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p2.To = p.To
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if p.From.Name == obj.NAME_EXTERN {
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p2.From.Reg = REG_R15
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p2.From.Name = obj.NAME_NONE
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p2.From.Sym = nil
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} else if p.To.Name == obj.NAME_EXTERN {
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p2.To.Reg = REG_R15
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p2.To.Name = obj.NAME_NONE
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p2.To.Sym = nil
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} else {
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return
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}
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l := p.Link
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l2 := p2.Link
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*p = *p1
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*p1 = *p2
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p.Link = l
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p1.Link = l2
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// We only care about global data: NAME_EXTERN means a global
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// symbol in the Go sense, and p.Sym.Local is true for a few
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// internally defined symbols.
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if p.As == ALEAQ && p.From.Type == obj.TYPE_MEM && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
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// LEAQ sym, Rx becomes MOVQ $sym, Rx which will be rewritten below
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p.As = AMOVQ
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p.From.Type = obj.TYPE_ADDR
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}
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if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
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// MOVQ $sym, Rx becomes MOVQ sym@GOT, Rx
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// MOVQ $sym+<off>, Rx becomes MOVQ sym@GOT, Rx; ADDQ <off>, Rx
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if p.As != AMOVQ {
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ctxt.Diag("do not know how to handle TYPE_ADDR in %v with -dynlink", p)
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}
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if p.To.Type != obj.TYPE_REG {
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ctxt.Diag("do not know how to handle LEAQ-type insn to non-register in %v with -dynlink", p)
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}
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p.From.Type = obj.TYPE_MEM
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p.From.Name = obj.NAME_GOTREF
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if p.From.Offset != 0 {
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q := obj.Appendp(ctxt, p)
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q.As = AADDQ
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q.From.Type = obj.TYPE_CONST
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q.From.Offset = p.From.Offset
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q.To = p.To
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p.From.Offset = 0
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}
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}
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if p.From3 != nil && p.From3.Name == obj.NAME_EXTERN {
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ctxt.Diag("don't know how to handle %v with -dynlink", p)
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}
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var source *obj.Addr
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// MOVx sym, Ry becomes MOVW sym@GOT, R15; MOVx (R15), Ry
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// MOVx Ry, sym becomes MOVW sym@GOT, R15; MOVx Ry, (R15)
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// An addition may be inserted between the two MOVs if there is an offset.
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if p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local {
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if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local {
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ctxt.Diag("cannot handle NAME_EXTERN on both sides in %v with -dynlink", p)
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}
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source = &p.From
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} else if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local {
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source = &p.To
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} else {
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return
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}
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if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ACALL || p.As == obj.ARET || p.As == obj.AJMP {
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return
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}
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if source.Type != obj.TYPE_MEM {
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ctxt.Diag("don't know how to handle %v with -dynlink", p)
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}
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p1 := obj.Appendp(ctxt, p)
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p2 := obj.Appendp(ctxt, p1)
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p1.As = AMOVQ
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p1.From.Type = obj.TYPE_MEM
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p1.From.Sym = source.Sym
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p1.From.Name = obj.NAME_GOTREF
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p1.To.Type = obj.TYPE_REG
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p1.To.Reg = REG_R15
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p2.As = p.As
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p2.From = p.From
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p2.To = p.To
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if p.From.Name == obj.NAME_EXTERN {
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p2.From.Reg = REG_R15
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p2.From.Name = obj.NAME_NONE
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p2.From.Sym = nil
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} else if p.To.Name == obj.NAME_EXTERN {
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p2.To.Reg = REG_R15
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p2.To.Name = obj.NAME_NONE
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p2.To.Sym = nil
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} else {
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return
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}
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obj.Nopout(p)
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}
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func nacladdr(ctxt *obj.Link, p *obj.Prog, a *obj.Addr) {
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@ -24,13 +24,13 @@ LEAQ name+10(SB), AX -> MOVQ name@GOT(SB), AX; ADDQ $10, AX
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MOVQ $name(SB), AX -> MOVQ name@GOT(SB), AX
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MOVQ $name+10(SB), AX -> MOVQ name@GOT(SB), AX; ADDQ $10, AX
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MOVQ name(SB), AX -> MOVQ name@GOT(SB), R15; MOVQ (R15), AX
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MOVQ name+10(SB), AX -> MOVQ name@GOT(SB), R15; MOVQ 10(R15), AX
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MOVQ name(SB), AX -> NOP; MOVQ name@GOT(SB), R15; MOVQ (R15), AX
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MOVQ name+10(SB), AX -> NOP; MOVQ name@GOT(SB), R15; MOVQ 10(R15), AX
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CMPQ name(SB), $0 -> MOVQ name@GOT(SB), R15; CMPQ (R15), $0
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CMPQ name(SB), $0 -> NOP; MOVQ name@GOT(SB), R15; CMPQ (R15), $0
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MOVQ $1, name(SB) -> MOVQ name@GOT(SB), R15; MOVQ $1, (R15)
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MOVQ $1, name+10(SB) -> MOVQ name@GOT(SB), R15; MOVQ $1, 10(R15)
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MOVQ $1, name(SB) -> NOP; MOVQ name@GOT(SB), R15; MOVQ $1, (R15)
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MOVQ $1, name+10(SB) -> NOP; MOVQ name@GOT(SB), R15; MOVQ $1, 10(R15)
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`
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type ParsedTestData struct {
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