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cmd/compile: make amd64 version of zerorange regabi-friendly
Change the amd64 version of 'zerorange' to avoid using RAX/RDI, since it can be called in a context when one of these registers is live (contains an incoming parameter). Updates #40724. Change-Id: Ibfa2b4e156b876354d4f8bd04eb8773c7056d948 Reviewed-on: https://go-review.googlesource.com/c/go/+/305829 Trust: Than McIntosh <thanm@google.com> Reviewed-by: Cherry Zhang <cherryyz@google.com> Reviewed-by: David Chase <drchase@google.com>
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@ -56,7 +56,7 @@ func dzDI(b int64) int64 {
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func zerorange(pp *objw.Progs, p *obj.Prog, off, cnt int64, state *uint32) *obj.Prog {
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const (
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ax = 1 << iota // if AX is already zeroed.
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r13 = 1 << iota // if R13 is already zeroed.
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x15 // if X15 is already zeroed. Note: in new ABI, X15 is always zero.
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)
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@ -69,21 +69,21 @@ func zerorange(pp *objw.Progs, p *obj.Prog, off, cnt int64, state *uint32) *obj.
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if cnt%int64(types.PtrSize) != 0 {
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base.Fatalf("zerorange count not a multiple of widthptr %d", cnt)
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}
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if *state&ax == 0 {
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p = pp.Append(p, x86.AMOVQ, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, x86.REG_AX, 0)
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*state |= ax
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if *state&r13 == 0 {
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p = pp.Append(p, x86.AMOVQ, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, x86.REG_R13, 0)
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*state |= r13
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}
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p = pp.Append(p, x86.AMOVL, obj.TYPE_REG, x86.REG_AX, 0, obj.TYPE_MEM, x86.REG_SP, off)
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p = pp.Append(p, x86.AMOVL, obj.TYPE_REG, x86.REG_R13, 0, obj.TYPE_MEM, x86.REG_SP, off)
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off += int64(types.PtrSize)
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cnt -= int64(types.PtrSize)
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}
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if cnt == 8 {
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if *state&ax == 0 {
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p = pp.Append(p, x86.AMOVQ, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, x86.REG_AX, 0)
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*state |= ax
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if *state&r13 == 0 {
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p = pp.Append(p, x86.AMOVQ, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, x86.REG_R13, 0)
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*state |= r13
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}
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p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_AX, 0, obj.TYPE_MEM, x86.REG_SP, off)
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p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_R13, 0, obj.TYPE_MEM, x86.REG_SP, off)
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} else if !isPlan9 && cnt <= int64(8*types.RegSize) {
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if !objabi.Experiment.RegabiG && *state&x15 == 0 {
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p = pp.Append(p, x86.AXORPS, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_REG, x86.REG_X15, 0)
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@ -102,17 +102,23 @@ func zerorange(pp *objw.Progs, p *obj.Prog, off, cnt int64, state *uint32) *obj.
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p = pp.Append(p, x86.AXORPS, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_REG, x86.REG_X15, 0)
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*state |= x15
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}
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// Save DI to r12. With the amd64 Go register abi, DI can contain
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// an incoming parameter, whereas R12 is always scratch.
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p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_DI, 0, obj.TYPE_REG, x86.REG_R12, 0)
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// Emit duffzero call
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p = pp.Append(p, leaptr, obj.TYPE_MEM, x86.REG_SP, off+dzDI(cnt), obj.TYPE_REG, x86.REG_DI, 0)
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p = pp.Append(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_ADDR, 0, dzOff(cnt))
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p.To.Sym = ir.Syms.Duffzero
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if cnt%16 != 0 {
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p = pp.Append(p, x86.AMOVUPS, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_MEM, x86.REG_DI, -int64(8))
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}
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// Restore DI from r12
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p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_R12, 0, obj.TYPE_REG, x86.REG_DI, 0)
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} else {
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if *state&ax == 0 {
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p = pp.Append(p, x86.AMOVQ, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, x86.REG_AX, 0)
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*state |= ax
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if *state&r13 == 0 {
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p = pp.Append(p, x86.AMOVQ, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, x86.REG_R13, 0)
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*state |= r13
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}
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p = pp.Append(p, x86.AMOVQ, obj.TYPE_CONST, 0, cnt/int64(types.RegSize), obj.TYPE_REG, x86.REG_CX, 0)
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