803 lines
21 KiB
Go
803 lines
21 KiB
Go
// Based on cmd/internal/obj/ppc64/obj9.go.
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//
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// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
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// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
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// Portions Copyright © 1997-1999 Vita Nuova Limited
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// Portions Copyright © 2000-2008 Vita Nuova Holdings Limited (www.vitanuova.com)
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// Portions Copyright © 2004,2006 Bruce Ellis
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// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
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// Revisions Copyright © 2000-2008 Lucent Technologies Inc. and others
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// Portions Copyright © 2009 The Go Authors. All rights reserved.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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package s390x
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import (
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"git.gammaspectra.live/WeebDataHoarder/compute-go/assembler/abi"
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"git.gammaspectra.live/WeebDataHoarder/compute-go/assembler/obj"
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"git.gammaspectra.live/WeebDataHoarder/compute-go/assembler/objabi"
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"git.gammaspectra.live/WeebDataHoarder/compute-go/assembler/sys"
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"log"
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"math"
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)
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func progedit(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) {
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p.From.Class = 0
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p.To.Class = 0
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c := ctxtz{ctxt: ctxt, newprog: newprog}
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// Rewrite BR/BL to symbol as TYPE_BRANCH.
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switch p.As {
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case ABR, ABL, obj.ARET, obj.ADUFFZERO, obj.ADUFFCOPY:
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if p.To.Sym != nil {
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p.To.Type = obj.TYPE_BRANCH
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}
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}
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// Rewrite float constants to values stored in memory unless they are +0.
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switch p.As {
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case AFMOVS:
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if p.From.Type == obj.TYPE_FCONST {
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f32 := float32(p.From.Val.(float64))
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if math.Float32bits(f32) == 0 { // +0
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break
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}
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p.From.Type = obj.TYPE_MEM
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p.From.Sym = ctxt.Float32Sym(f32)
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p.From.Name = obj.NAME_EXTERN
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p.From.Offset = 0
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}
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case AFMOVD:
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if p.From.Type == obj.TYPE_FCONST {
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f64 := p.From.Val.(float64)
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if math.Float64bits(f64) == 0 { // +0
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break
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}
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p.From.Type = obj.TYPE_MEM
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p.From.Sym = ctxt.Float64Sym(f64)
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p.From.Name = obj.NAME_EXTERN
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p.From.Offset = 0
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}
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// put constants not loadable by LOAD IMMEDIATE into memory
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case AMOVD:
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if p.From.Type == obj.TYPE_CONST {
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val := p.From.Offset
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if int64(int32(val)) != val &&
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int64(uint32(val)) != val &&
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int64(uint64(val)&(0xffffffff<<32)) != val {
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p.From.Type = obj.TYPE_MEM
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p.From.Sym = ctxt.Int64Sym(p.From.Offset)
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p.From.Name = obj.NAME_EXTERN
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p.From.Offset = 0
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}
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}
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}
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// Rewrite SUB constants into ADD.
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switch p.As {
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case ASUBC:
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if p.From.Type == obj.TYPE_CONST && isint32(-p.From.Offset) {
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p.From.Offset = -p.From.Offset
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p.As = AADDC
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}
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case ASUB:
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if p.From.Type == obj.TYPE_CONST && isint32(-p.From.Offset) {
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p.From.Offset = -p.From.Offset
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p.As = AADD
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}
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}
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if c.ctxt.Flag_dynlink {
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c.rewriteToUseGot(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 (c *ctxtz) rewriteToUseGot(p *obj.Prog) {
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// At the moment EXRL instructions are not emitted by the compiler and only reference local symbols in
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// assembly code.
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if p.As == AEXRL {
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return
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}
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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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// Rewrites must not clobber flags and therefore cannot use the
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// ADD instruction.
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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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// MOVD $sym, Rx becomes MOVD sym@GOT, Rx
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// MOVD $sym+<off>, Rx becomes MOVD sym@GOT, Rx or REGTMP2; MOVD $<off>(Rx or REGTMP2), Rx
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if p.To.Type != obj.TYPE_REG || p.As != AMOVD {
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c.ctxt.Diag("do not know how to handle LEA-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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q := p
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if p.From.Offset != 0 {
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target := p.To.Reg
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if target == REG_R0 {
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// Cannot use R0 as input to address calculation.
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// REGTMP might be used by the assembler.
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p.To.Reg = REGTMP2
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}
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q = obj.Appendp(q, c.newprog)
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q.As = AMOVD
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q.From.Type = obj.TYPE_ADDR
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q.From.Offset = p.From.Offset
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q.From.Reg = p.To.Reg
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q.To.Type = obj.TYPE_REG
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q.To.Reg = target
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p.From.Offset = 0
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}
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}
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if p.GetFrom3() != nil && p.GetFrom3().Name == obj.NAME_EXTERN {
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c.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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// MOVD sym, Ry becomes MOVD sym@GOT, REGTMP2; MOVD (REGTMP2), Ry
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// MOVD Ry, sym becomes MOVD sym@GOT, REGTMP2; MOVD Ry, (REGTMP2)
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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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c.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.Sym.Type == objabi.STLSBSS {
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return
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}
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if source.Type != obj.TYPE_MEM {
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c.ctxt.Diag("don't know how to handle %v with -dynlink", p)
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}
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p1 := obj.Appendp(p, c.newprog)
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p2 := obj.Appendp(p1, c.newprog)
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p1.As = AMOVD
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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 = REGTMP2
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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 = REGTMP2
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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 = REGTMP2
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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 preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
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// TODO(minux): add morestack short-cuts with small fixed frame-size.
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if cursym.Func().Text == nil || cursym.Func().Text.Link == nil {
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return
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}
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c := ctxtz{ctxt: ctxt, cursym: cursym, newprog: newprog}
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p := c.cursym.Func().Text
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textstksiz := p.To.Offset
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if textstksiz == -8 {
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// Compatibility hack.
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p.From.Sym.Set(obj.AttrNoFrame, true)
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textstksiz = 0
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}
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if textstksiz%8 != 0 {
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c.ctxt.Diag("frame size %d not a multiple of 8", textstksiz)
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}
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if p.From.Sym.NoFrame() {
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if textstksiz != 0 {
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c.ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", textstksiz)
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}
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}
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c.cursym.Func().Args = p.To.Val.(int32)
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c.cursym.Func().Locals = int32(textstksiz)
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/*
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* find leaf subroutines
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* strip NOPs
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* expand RET
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*/
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var q *obj.Prog
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for p := c.cursym.Func().Text; p != nil; p = p.Link {
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switch p.As {
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case obj.ATEXT:
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q = p
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p.Mark |= LEAF
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case ABL, ABCL:
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q = p
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c.cursym.Func().Text.Mark &^= LEAF
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fallthrough
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case ABC,
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ABRC,
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ABEQ,
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ABGE,
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ABGT,
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ABLE,
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ABLT,
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ABLEU,
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ABLTU,
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ABNE,
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ABR,
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ABVC,
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ABVS,
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ACRJ,
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ACGRJ,
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ACLRJ,
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ACLGRJ,
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ACIJ,
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ACGIJ,
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ACLIJ,
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ACLGIJ,
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ACMPBEQ,
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ACMPBGE,
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ACMPBGT,
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ACMPBLE,
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ACMPBLT,
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ACMPBNE,
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ACMPUBEQ,
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ACMPUBGE,
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ACMPUBGT,
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ACMPUBLE,
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ACMPUBLT,
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ACMPUBNE:
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q = p
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p.Mark |= BRANCH
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default:
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q = p
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}
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}
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autosize := int32(0)
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var pLast *obj.Prog
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var pPre *obj.Prog
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var pPreempt *obj.Prog
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var pCheck *obj.Prog
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wasSplit := false
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for p := c.cursym.Func().Text; p != nil; p = p.Link {
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pLast = p
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switch p.As {
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case obj.ATEXT:
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autosize = int32(textstksiz)
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if p.Mark&LEAF != 0 && autosize == 0 {
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// A leaf function with no locals has no frame.
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p.From.Sym.Set(obj.AttrNoFrame, true)
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}
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if !p.From.Sym.NoFrame() {
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// If there is a stack frame at all, it includes
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// space to save the LR.
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autosize += int32(c.ctxt.Arch.FixedFrameSize)
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}
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if p.Mark&LEAF != 0 && autosize < abi.StackSmall {
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// A leaf function with a small stack can be marked
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// NOSPLIT, avoiding a stack check.
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p.From.Sym.Set(obj.AttrNoSplit, true)
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}
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p.To.Offset = int64(autosize)
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q := p
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if !p.From.Sym.NoSplit() {
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p, pPreempt, pCheck = c.stacksplitPre(p, autosize) // emit pre part of split check
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pPre = p
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p = c.ctxt.EndUnsafePoint(p, c.newprog, -1)
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wasSplit = true //need post part of split
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}
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if autosize != 0 {
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// Make sure to save link register for non-empty frame, even if
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// it is a leaf function, so that traceback works.
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// Store link register before decrementing SP, so if a signal comes
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// during the execution of the function prologue, the traceback
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// code will not see a half-updated stack frame.
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// This sequence is not async preemptible, as if we open a frame
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// at the current SP, it will clobber the saved LR.
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q = c.ctxt.StartUnsafePoint(p, c.newprog)
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q = obj.Appendp(q, c.newprog)
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q.As = AMOVD
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q.From.Type = obj.TYPE_REG
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q.From.Reg = REG_LR
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q.To.Type = obj.TYPE_MEM
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q.To.Reg = REGSP
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q.To.Offset = int64(-autosize)
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q = obj.Appendp(q, c.newprog)
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q.As = AMOVD
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q.From.Type = obj.TYPE_ADDR
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q.From.Offset = int64(-autosize)
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q.From.Reg = REGSP // not actually needed - REGSP is assumed if no reg is provided
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q.To.Type = obj.TYPE_REG
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q.To.Reg = REGSP
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q.Spadj = autosize
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q = c.ctxt.EndUnsafePoint(q, c.newprog, -1)
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// On Linux, in a cgo binary we may get a SIGSETXID signal early on
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// before the signal stack is set, as glibc doesn't allow us to block
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// SIGSETXID. So a signal may land on the current stack and clobber
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// the content below the SP. We store the LR again after the SP is
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// decremented.
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q = obj.Appendp(q, c.newprog)
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q.As = AMOVD
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q.From.Type = obj.TYPE_REG
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q.From.Reg = REG_LR
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q.To.Type = obj.TYPE_MEM
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q.To.Reg = REGSP
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q.To.Offset = 0
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} else if c.cursym.Func().Text.Mark&LEAF == 0 {
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// A very few functions that do not return to their caller
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// (e.g. gogo) are not identified as leaves but still have
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// no frame.
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c.cursym.Func().Text.Mark |= LEAF
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}
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if c.cursym.Func().Text.Mark&LEAF != 0 {
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c.cursym.Set(obj.AttrLeaf, true)
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break
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}
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if c.cursym.Func().Text.From.Sym.Wrapper() {
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// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
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//
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// MOVD g_panic(g), R3
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// CMP R3, $0
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// BEQ end
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// MOVD panic_argp(R3), R4
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// ADD $(autosize+8), R1, R5
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// CMP R4, R5
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// BNE end
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// ADD $8, R1, R6
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// MOVD R6, panic_argp(R3)
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// end:
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// NOP
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//
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// The NOP is needed to give the jumps somewhere to land.
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// It is a liblink NOP, not a s390x NOP: it encodes to 0 instruction bytes.
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q = obj.Appendp(q, c.newprog)
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q.As = AMOVD
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q.From.Type = obj.TYPE_MEM
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q.From.Reg = REGG
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q.From.Offset = 4 * int64(c.ctxt.Arch.PtrSize) // G.panic
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q.To.Type = obj.TYPE_REG
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q.To.Reg = REG_R3
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q = obj.Appendp(q, c.newprog)
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q.As = ACMP
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q.From.Type = obj.TYPE_REG
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q.From.Reg = REG_R3
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q.To.Type = obj.TYPE_CONST
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q.To.Offset = 0
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q = obj.Appendp(q, c.newprog)
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q.As = ABEQ
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q.To.Type = obj.TYPE_BRANCH
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p1 := q
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q = obj.Appendp(q, c.newprog)
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q.As = AMOVD
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q.From.Type = obj.TYPE_MEM
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q.From.Reg = REG_R3
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q.From.Offset = 0 // Panic.argp
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q.To.Type = obj.TYPE_REG
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q.To.Reg = REG_R4
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q = obj.Appendp(q, c.newprog)
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q.As = AADD
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q.From.Type = obj.TYPE_CONST
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q.From.Offset = int64(autosize) + c.ctxt.Arch.FixedFrameSize
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q.Reg = REGSP
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q.To.Type = obj.TYPE_REG
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q.To.Reg = REG_R5
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q = obj.Appendp(q, c.newprog)
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q.As = ACMP
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q.From.Type = obj.TYPE_REG
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q.From.Reg = REG_R4
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q.To.Type = obj.TYPE_REG
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q.To.Reg = REG_R5
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q = obj.Appendp(q, c.newprog)
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q.As = ABNE
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q.To.Type = obj.TYPE_BRANCH
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p2 := q
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q = obj.Appendp(q, c.newprog)
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q.As = AADD
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q.From.Type = obj.TYPE_CONST
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q.From.Offset = c.ctxt.Arch.FixedFrameSize
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q.Reg = REGSP
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q.To.Type = obj.TYPE_REG
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q.To.Reg = REG_R6
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q = obj.Appendp(q, c.newprog)
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q.As = AMOVD
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q.From.Type = obj.TYPE_REG
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q.From.Reg = REG_R6
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q.To.Type = obj.TYPE_MEM
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q.To.Reg = REG_R3
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q.To.Offset = 0 // Panic.argp
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q = obj.Appendp(q, c.newprog)
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q.As = obj.ANOP
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p1.To.SetTarget(q)
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p2.To.SetTarget(q)
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}
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case obj.ARET:
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retTarget := p.To.Sym
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if c.cursym.Func().Text.Mark&LEAF != 0 {
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if autosize == 0 {
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|
p.As = ABR
|
|
p.From = obj.Addr{}
|
|
if retTarget == nil {
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REG_LR
|
|
} else {
|
|
p.To.Type = obj.TYPE_BRANCH
|
|
p.To.Sym = retTarget
|
|
}
|
|
p.Mark |= BRANCH
|
|
break
|
|
}
|
|
|
|
p.As = AADD
|
|
p.From.Type = obj.TYPE_CONST
|
|
p.From.Offset = int64(autosize)
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REGSP
|
|
p.Spadj = -autosize
|
|
|
|
q = obj.Appendp(p, c.newprog)
|
|
q.As = ABR
|
|
q.From = obj.Addr{}
|
|
if retTarget == nil {
|
|
q.To.Type = obj.TYPE_REG
|
|
q.To.Reg = REG_LR
|
|
} else {
|
|
q.To.Type = obj.TYPE_BRANCH
|
|
q.To.Sym = retTarget
|
|
}
|
|
q.Mark |= BRANCH
|
|
q.Spadj = autosize
|
|
break
|
|
}
|
|
|
|
p.As = AMOVD
|
|
p.From.Type = obj.TYPE_MEM
|
|
p.From.Reg = REGSP
|
|
p.From.Offset = 0
|
|
p.To = obj.Addr{
|
|
Type: obj.TYPE_REG,
|
|
Reg: REG_LR,
|
|
}
|
|
|
|
q = p
|
|
|
|
if autosize != 0 {
|
|
q = obj.Appendp(q, c.newprog)
|
|
q.As = AADD
|
|
q.From.Type = obj.TYPE_CONST
|
|
q.From.Offset = int64(autosize)
|
|
q.To.Type = obj.TYPE_REG
|
|
q.To.Reg = REGSP
|
|
q.Spadj = -autosize
|
|
}
|
|
|
|
q = obj.Appendp(q, c.newprog)
|
|
q.As = ABR
|
|
q.From = obj.Addr{}
|
|
if retTarget == nil {
|
|
q.To.Type = obj.TYPE_REG
|
|
q.To.Reg = REG_LR
|
|
} else {
|
|
q.To.Type = obj.TYPE_BRANCH
|
|
q.To.Sym = retTarget
|
|
}
|
|
q.Mark |= BRANCH
|
|
q.Spadj = autosize
|
|
|
|
case AADD:
|
|
if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.From.Type == obj.TYPE_CONST {
|
|
p.Spadj = int32(-p.From.Offset)
|
|
}
|
|
|
|
case obj.AGETCALLERPC:
|
|
if cursym.Leaf() {
|
|
/* MOVD LR, Rd */
|
|
p.As = AMOVD
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = REG_LR
|
|
} else {
|
|
/* MOVD (RSP), Rd */
|
|
p.As = AMOVD
|
|
p.From.Type = obj.TYPE_MEM
|
|
p.From.Reg = REGSP
|
|
}
|
|
}
|
|
|
|
if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.Spadj == 0 {
|
|
f := c.cursym.Func()
|
|
if f.FuncFlag&abi.FuncFlagSPWrite == 0 {
|
|
c.cursym.Func().FuncFlag |= abi.FuncFlagSPWrite
|
|
if ctxt.Debugvlog || !ctxt.IsAsm {
|
|
ctxt.Logf("auto-SPWRITE: %s\n", c.cursym.Name)
|
|
if !ctxt.IsAsm {
|
|
ctxt.Diag("invalid auto-SPWRITE in non-assembly")
|
|
ctxt.DiagFlush()
|
|
log.Fatalf("bad SPWRITE")
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if wasSplit {
|
|
c.stacksplitPost(pLast, pPre, pPreempt, pCheck, autosize) // emit post part of split check
|
|
}
|
|
}
|
|
|
|
// stacksplitPre generates the function stack check prologue following
|
|
// Prog p (which should be the TEXT Prog). It returns one or two
|
|
// branch Progs that must be patched to jump to the morestack epilogue,
|
|
// and the Prog that starts the morestack check.
|
|
func (c *ctxtz) stacksplitPre(p *obj.Prog, framesize int32) (pPre, pPreempt, pCheck *obj.Prog) {
|
|
if c.ctxt.Flag_maymorestack != "" {
|
|
// Save LR and REGCTXT
|
|
const frameSize = 16
|
|
p = c.ctxt.StartUnsafePoint(p, c.newprog)
|
|
// MOVD LR, -16(SP)
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = AMOVD
|
|
p.From = obj.Addr{Type: obj.TYPE_REG, Reg: REG_LR}
|
|
p.To = obj.Addr{Type: obj.TYPE_MEM, Reg: REGSP, Offset: -frameSize}
|
|
// MOVD $-16(SP), SP
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = AMOVD
|
|
p.From = obj.Addr{Type: obj.TYPE_ADDR, Offset: -frameSize, Reg: REGSP}
|
|
p.To = obj.Addr{Type: obj.TYPE_REG, Reg: REGSP}
|
|
p.Spadj = frameSize
|
|
// MOVD REGCTXT, 8(SP)
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = AMOVD
|
|
p.From = obj.Addr{Type: obj.TYPE_REG, Reg: REGCTXT}
|
|
p.To = obj.Addr{Type: obj.TYPE_MEM, Reg: REGSP, Offset: 8}
|
|
|
|
// BL maymorestack
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = ABL
|
|
// See ../x86/obj6.go
|
|
sym := c.ctxt.LookupABI(c.ctxt.Flag_maymorestack, c.cursym.ABI())
|
|
p.To = obj.Addr{Type: obj.TYPE_BRANCH, Sym: sym}
|
|
|
|
// Restore LR and REGCTXT
|
|
|
|
// MOVD REGCTXT, 8(SP)
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = AMOVD
|
|
p.From = obj.Addr{Type: obj.TYPE_MEM, Reg: REGSP, Offset: 8}
|
|
p.To = obj.Addr{Type: obj.TYPE_REG, Reg: REGCTXT}
|
|
// MOVD (SP), LR
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = AMOVD
|
|
p.From = obj.Addr{Type: obj.TYPE_MEM, Reg: REGSP, Offset: 0}
|
|
p.To = obj.Addr{Type: obj.TYPE_REG, Reg: REG_LR}
|
|
// MOVD $16(SP), SP
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = AMOVD
|
|
p.From = obj.Addr{Type: obj.TYPE_CONST, Reg: REGSP, Offset: frameSize}
|
|
p.To = obj.Addr{Type: obj.TYPE_REG, Reg: REGSP}
|
|
p.Spadj = -frameSize
|
|
|
|
p = c.ctxt.EndUnsafePoint(p, c.newprog, -1)
|
|
}
|
|
|
|
// MOVD g_stackguard(g), R3
|
|
p = obj.Appendp(p, c.newprog)
|
|
// Jump back to here after morestack returns.
|
|
pCheck = p
|
|
|
|
p.As = AMOVD
|
|
p.From.Type = obj.TYPE_MEM
|
|
p.From.Reg = REGG
|
|
p.From.Offset = 2 * int64(c.ctxt.Arch.PtrSize) // G.stackguard0
|
|
if c.cursym.CFunc() {
|
|
p.From.Offset = 3 * int64(c.ctxt.Arch.PtrSize) // G.stackguard1
|
|
}
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REG_R3
|
|
|
|
// Mark the stack bound check and morestack call async nonpreemptible.
|
|
// If we get preempted here, when resumed the preemption request is
|
|
// cleared, but we'll still call morestack, which will double the stack
|
|
// unnecessarily. See issue #35470.
|
|
p = c.ctxt.StartUnsafePoint(p, c.newprog)
|
|
|
|
if framesize <= abi.StackSmall {
|
|
// small stack: SP < stackguard
|
|
// CMPUBGE stackguard, SP, label-of-call-to-morestack
|
|
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = REG_R3
|
|
p.Reg = REGSP
|
|
p.As = ACMPUBGE
|
|
p.To.Type = obj.TYPE_BRANCH
|
|
|
|
return p, nil, pCheck
|
|
}
|
|
|
|
// large stack: SP-framesize < stackguard-StackSmall
|
|
|
|
offset := int64(framesize) - abi.StackSmall
|
|
if framesize > abi.StackBig {
|
|
// Such a large stack we need to protect against underflow.
|
|
// The runtime guarantees SP > objabi.StackBig, but
|
|
// framesize is large enough that SP-framesize may
|
|
// underflow, causing a direct comparison with the
|
|
// stack guard to incorrectly succeed. We explicitly
|
|
// guard against underflow.
|
|
//
|
|
// MOVD $(framesize-StackSmall), R4
|
|
// CMPUBLT SP, R4, label-of-call-to-morestack
|
|
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = AMOVD
|
|
p.From.Type = obj.TYPE_CONST
|
|
p.From.Offset = offset
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REG_R4
|
|
|
|
p = obj.Appendp(p, c.newprog)
|
|
pPreempt = p
|
|
p.As = ACMPUBLT
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = REGSP
|
|
p.Reg = REG_R4
|
|
p.To.Type = obj.TYPE_BRANCH
|
|
}
|
|
|
|
// Check against the stack guard. We've ensured this won't underflow.
|
|
// ADD $-(framesize-StackSmall), SP, R4
|
|
// CMPUBGE stackguard, R4, label-of-call-to-morestack
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = AADD
|
|
p.From.Type = obj.TYPE_CONST
|
|
p.From.Offset = -offset
|
|
p.Reg = REGSP
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REG_R4
|
|
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = REG_R3
|
|
p.Reg = REG_R4
|
|
p.As = ACMPUBGE
|
|
p.To.Type = obj.TYPE_BRANCH
|
|
|
|
return p, pPreempt, pCheck
|
|
}
|
|
|
|
// stacksplitPost generates the function epilogue that calls morestack
|
|
// and returns the new last instruction in the function.
|
|
//
|
|
// p is the last Prog in the function. pPre and pPreempt, if non-nil,
|
|
// are the instructions that branch to the epilogue. This will fill in
|
|
// their branch targets. pCheck is the Prog that begins the stack check.
|
|
func (c *ctxtz) stacksplitPost(p *obj.Prog, pPre, pPreempt, pCheck *obj.Prog, framesize int32) *obj.Prog {
|
|
// Now we are at the end of the function, but logically
|
|
// we are still in function prologue. We need to fix the
|
|
// SP data and PCDATA.
|
|
spfix := obj.Appendp(p, c.newprog)
|
|
spfix.As = obj.ANOP
|
|
spfix.Spadj = -framesize
|
|
|
|
pcdata := c.ctxt.EmitEntryStackMap(c.cursym, spfix, c.newprog)
|
|
pcdata = c.ctxt.StartUnsafePoint(pcdata, c.newprog)
|
|
|
|
// MOVD LR, R5
|
|
p = obj.Appendp(pcdata, c.newprog)
|
|
pPre.To.SetTarget(p)
|
|
p.As = AMOVD
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = REG_LR
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REG_R5
|
|
if pPreempt != nil {
|
|
pPreempt.To.SetTarget(p)
|
|
}
|
|
|
|
// BL runtime.morestack(SB)
|
|
p = obj.Appendp(p, c.newprog)
|
|
|
|
p.As = ABL
|
|
p.To.Type = obj.TYPE_BRANCH
|
|
if c.cursym.CFunc() {
|
|
p.To.Sym = c.ctxt.Lookup("runtime.morestackc")
|
|
} else if !c.cursym.Func().Text.From.Sym.NeedCtxt() {
|
|
p.To.Sym = c.ctxt.Lookup("runtime.morestack_noctxt")
|
|
} else {
|
|
p.To.Sym = c.ctxt.Lookup("runtime.morestack")
|
|
}
|
|
|
|
p = c.ctxt.EndUnsafePoint(p, c.newprog, -1)
|
|
|
|
// BR pCheck
|
|
p = obj.Appendp(p, c.newprog)
|
|
|
|
p.As = ABR
|
|
p.To.Type = obj.TYPE_BRANCH
|
|
p.To.SetTarget(pCheck)
|
|
return p
|
|
}
|
|
|
|
var unaryDst = map[obj.As]bool{
|
|
ASTCK: true,
|
|
ASTCKC: true,
|
|
ASTCKE: true,
|
|
ASTCKF: true,
|
|
ANEG: true,
|
|
ANEGW: true,
|
|
AVONE: true,
|
|
AVZERO: true,
|
|
}
|
|
|
|
var Links390x = obj.LinkArch{
|
|
Arch: sys.ArchS390X,
|
|
Init: buildop,
|
|
Preprocess: preprocess,
|
|
Assemble: spanz,
|
|
Progedit: progedit,
|
|
UnaryDst: unaryDst,
|
|
DWARFRegisters: S390XDWARFRegisters,
|
|
}
|