diff options
Diffstat (limited to 'src/cmd/internal/obj/x86/obj6.go')
| -rw-r--r-- | src/cmd/internal/obj/x86/obj6.go | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/src/cmd/internal/obj/x86/obj6.go b/src/cmd/internal/obj/x86/obj6.go index 9a47ae16ed..7b868bafdb 100644 --- a/src/cmd/internal/obj/x86/obj6.go +++ b/src/cmd/internal/obj/x86/obj6.go @@ -334,6 +334,16 @@ func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog) { lea = ALEAL mov = AMOVL reg = REG_CX + if p.To.Type == obj.TYPE_REG && p.To.Reg != p.From.Reg && p.To.Reg != p.From.Index { + switch p.As { + case ALEAL, AMOVL, AMOVWLZX, AMOVBLZX, AMOVWLSX, AMOVBLSX: + // Special case: clobber the destination register with + // the PC so we don't have to clobber CX. + // The SSA backend depends on CX not being clobbered across these instructions. + // See cmd/compile/internal/ssa/gen/386.rules (search for Flag_shared). + reg = p.To.Reg + } + } } if p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO { @@ -392,7 +402,7 @@ func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog) { dest = p.To p.As = mov p.To.Type = obj.TYPE_REG - p.To.Reg = REG_CX + p.To.Reg = reg p.To.Sym = nil p.To.Name = obj.NAME_NONE } @@ -413,7 +423,7 @@ func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog) { q.As = pAs q.To = dest q.From.Type = obj.TYPE_REG - q.From.Reg = REG_CX + q.From.Reg = reg } } if p.From3 != nil && p.From3.Name == obj.NAME_EXTERN { @@ -544,14 +554,11 @@ func rewriteToPcrel(ctxt *obj.Link, p *obj.Prog) { return } var dst int16 = REG_CX - if isName(&p.From) && p.To.Type == obj.TYPE_REG { + if p.To.Type == obj.TYPE_REG && p.To.Reg != p.From.Reg && p.To.Reg != p.From.Index { switch p.As { case ALEAL, AMOVL, AMOVWLZX, AMOVBLZX, AMOVWLSX, AMOVBLSX: dst = p.To.Reg - // Special case: clobber the destination register with - // the PC so we don't have to clobber CX. - // The SSA backend depends on CX not being clobbered across these instructions. - // See cmd/compile/internal/ssa/gen/386.rules (search for Flag_shared). + // Why? See the comment near the top of rewriteToUseGot above. } } q := obj.Appendp(ctxt, p) |