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cmd/internal/obj/x86: don't apply workaround for solaris to darwin
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Currently, we have a workaround for solaris that enforce aboslute
addressing for external symbols. However, We don't want to use the
workaround for darwin.
This CL also refactors code a little bit, because the original function
name is not appropriate now.

Updates #17490

Change-Id: Id21f9cdf33dca6a40647226be49010c2c324ee24
Reviewed-on: https://go-review.googlesource.com/54871
Reviewed-by: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>
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hirochachacha authored and ianlancetaylor committed Aug 17, 2017
1 parent 78984d3 commit 0d65cd6
Showing 1 changed file with 11 additions and 8 deletions.
19 changes: 11 additions & 8 deletions src/cmd/internal/obj/x86/asm6.go
Original file line number Diff line number Diff line change
Expand Up @@ -1712,14 +1712,17 @@ var optab =

var opindex [(ALAST + 1) & obj.AMask]*Optab

// isextern reports whether s describes an external symbol that must avoid pc-relative addressing.
// useAbs reports whether s describes a symbol that must avoid pc-relative addressing.
// This happens on systems like Solaris that call .so functions instead of system calls.
// It does not seem to be necessary for any other systems. This is probably working
// around a Solaris-specific bug that should be fixed differently, but we don't know
// what that bug is. And this does fix it.
func isextern(s *obj.LSym) bool {
// All the Solaris dynamic imports from libc.so begin with "libc_".
return strings.HasPrefix(s.Name, "libc_")
func useAbs(ctxt *obj.Link, s *obj.LSym) bool {
if ctxt.Headtype == objabi.Hsolaris {
// All the Solaris dynamic imports from libc.so begin with "libc_".
return strings.HasPrefix(s.Name, "libc_")
}
return ctxt.Arch.Family == sys.I386 && !ctxt.Flag_shared
}

// single-instruction no-ops of various lengths.
Expand Down Expand Up @@ -2299,7 +2302,7 @@ func oclass(ctxt *obj.Link, p *obj.Prog, a *obj.Addr) int {

case obj.NAME_EXTERN,
obj.NAME_STATIC:
if a.Sym != nil && isextern(a.Sym) || (ctxt.Arch.Family == sys.I386 && !ctxt.Flag_shared) {
if a.Sym != nil && useAbs(ctxt, a.Sym) {
return Yi32
}
return Yiauto // use pc-relative addressing
Expand Down Expand Up @@ -2800,7 +2803,7 @@ func vaddr(ctxt *obj.Link, p *obj.Prog, a *obj.Addr, r *obj.Reloc) int64 {
if a.Name == obj.NAME_GOTREF {
r.Siz = 4
r.Type = objabi.R_GOTPCREL
} else if isextern(s) || (ctxt.Arch.Family != sys.AMD64 && !ctxt.Flag_shared) {
} else if useAbs(ctxt, s) {
r.Siz = 4
r.Type = objabi.R_ADDR
} else {
Expand Down Expand Up @@ -2883,7 +2886,7 @@ func (asmbuf *AsmBuf) asmandsz(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, a
case obj.NAME_EXTERN,
obj.NAME_GOTREF,
obj.NAME_STATIC:
if !isextern(a.Sym) && ctxt.Arch.Family == sys.AMD64 {
if !useAbs(ctxt, a.Sym) && ctxt.Arch.Family == sys.AMD64 {
goto bad
}
if ctxt.Arch.Family == sys.I386 && ctxt.Flag_shared {
Expand Down Expand Up @@ -2953,7 +2956,7 @@ func (asmbuf *AsmBuf) asmandsz(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, a

asmbuf.rexflag |= regrex[base]&Rxb | rex
if base == REG_NONE || (REG_CS <= base && base <= REG_GS) || base == REG_TLS {
if (a.Sym == nil || !isextern(a.Sym)) && base == REG_NONE && (a.Name == obj.NAME_STATIC || a.Name == obj.NAME_EXTERN || a.Name == obj.NAME_GOTREF) || ctxt.Arch.Family != sys.AMD64 {
if (a.Sym == nil || !useAbs(ctxt, a.Sym)) && base == REG_NONE && (a.Name == obj.NAME_STATIC || a.Name == obj.NAME_EXTERN || a.Name == obj.NAME_GOTREF) || ctxt.Arch.Family != sys.AMD64 {
if a.Name == obj.NAME_GOTREF && (a.Offset != 0 || a.Index != 0 || a.Scale != 0) {
ctxt.Diag("%v has offset against gotref", p)
}
Expand Down

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