785 lines
20 KiB
Go
785 lines
20 KiB
Go
// Derived from Inferno utils/5c/swt.c
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// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/5c/swt.c
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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 © 2000-2007 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 © 2000-2007 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 arm
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import (
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"github.com/twitchyliquid64/golang-asm/obj"
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"github.com/twitchyliquid64/golang-asm/objabi"
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"github.com/twitchyliquid64/golang-asm/sys"
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)
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var progedit_tlsfallback *obj.LSym
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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 := ctxt5{ctxt: ctxt, newprog: newprog}
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// Rewrite B/BL to symbol as TYPE_BRANCH.
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switch p.As {
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case AB, ABL, obj.ADUFFZERO, obj.ADUFFCOPY:
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if p.To.Type == obj.TYPE_MEM && (p.To.Name == obj.NAME_EXTERN || p.To.Name == obj.NAME_STATIC) && 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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// Replace TLS register fetches on older ARM processors.
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switch p.As {
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// Treat MRC 15, 0, <reg>, C13, C0, 3 specially.
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case AMRC:
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if p.To.Offset&0xffff0fff == 0xee1d0f70 {
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// Because the instruction might be rewritten to a BL which returns in R0
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// the register must be zero.
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if p.To.Offset&0xf000 != 0 {
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ctxt.Diag("%v: TLS MRC instruction must write to R0 as it might get translated into a BL instruction", p.Line())
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}
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if objabi.GOARM < 7 {
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// Replace it with BL runtime.read_tls_fallback(SB) for ARM CPUs that lack the tls extension.
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if progedit_tlsfallback == nil {
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progedit_tlsfallback = ctxt.Lookup("runtime.read_tls_fallback")
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}
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// MOVW LR, R11
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p.As = AMOVW
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p.From.Type = obj.TYPE_REG
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p.From.Reg = REGLINK
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REGTMP
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// BL runtime.read_tls_fallback(SB)
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p = obj.Appendp(p, newprog)
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p.As = ABL
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p.To.Type = obj.TYPE_BRANCH
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p.To.Sym = progedit_tlsfallback
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p.To.Offset = 0
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// MOVW R11, LR
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p = obj.Appendp(p, newprog)
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p.As = AMOVW
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p.From.Type = obj.TYPE_REG
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p.From.Reg = REGTMP
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REGLINK
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break
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}
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}
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// Otherwise, MRC/MCR instructions need no further treatment.
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p.As = AWORD
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}
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// Rewrite float constants to values stored in memory.
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switch p.As {
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case AMOVF:
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if p.From.Type == obj.TYPE_FCONST && c.chipfloat5(p.From.Val.(float64)) < 0 && (c.chipzero5(p.From.Val.(float64)) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) {
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f32 := float32(p.From.Val.(float64))
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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 AMOVD:
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if p.From.Type == obj.TYPE_FCONST && c.chipfloat5(p.From.Val.(float64)) < 0 && (c.chipzero5(p.From.Val.(float64)) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) {
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p.From.Type = obj.TYPE_MEM
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p.From.Sym = ctxt.Float64Sym(p.From.Val.(float64))
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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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if 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 *ctxt5) rewriteToUseGot(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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// MOVW runtime.duffxxx@GOT, R9
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// ADD $offset, R9
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// CALL (R9)
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var sym *obj.LSym
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if p.As == obj.ADUFFZERO {
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sym = c.ctxt.Lookup("runtime.duffzero")
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} else {
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sym = c.ctxt.Lookup("runtime.duffcopy")
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}
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offset := p.To.Offset
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p.As = AMOVW
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p.From.Type = obj.TYPE_MEM
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p.From.Name = obj.NAME_GOTREF
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p.From.Sym = sym
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REG_R9
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p.To.Name = obj.NAME_NONE
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p.To.Offset = 0
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p.To.Sym = nil
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p1 := obj.Appendp(p, c.newprog)
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p1.As = AADD
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p1.From.Type = obj.TYPE_CONST
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p1.From.Offset = offset
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p1.To.Type = obj.TYPE_REG
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p1.To.Reg = REG_R9
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p2 := obj.Appendp(p1, c.newprog)
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p2.As = obj.ACALL
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p2.To.Type = obj.TYPE_MEM
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p2.To.Reg = REG_R9
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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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if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() {
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// MOVW $sym, Rx becomes MOVW sym@GOT, Rx
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// MOVW $sym+<off>, Rx becomes MOVW sym@GOT, Rx; ADD <off>, Rx
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if p.As != AMOVW {
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c.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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c.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(p, 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 = 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.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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// MOVx sym, Ry becomes MOVW sym@GOT, R9; MOVx (R9), Ry
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// MOVx Ry, sym becomes MOVW sym@GOT, R9; MOVx Ry, (R9)
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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 = AMOVW
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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_R9
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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_R9
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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_R9
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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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// Prog.mark
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const (
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FOLL = 1 << 0
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LABEL = 1 << 1
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LEAF = 1 << 2
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)
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func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
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autosize := int32(0)
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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 := ctxt5{ctxt: ctxt, cursym: cursym, newprog: newprog}
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p := c.cursym.Func.Text
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autoffset := int32(p.To.Offset)
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if autoffset == -4 {
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// Historical way to mark NOFRAME.
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p.From.Sym.Set(obj.AttrNoFrame, true)
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autoffset = 0
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}
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if autoffset < 0 || autoffset%4 != 0 {
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c.ctxt.Diag("frame size %d not 0 or a positive multiple of 4", autoffset)
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}
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if p.From.Sym.NoFrame() {
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if autoffset != 0 {
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c.ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", autoffset)
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}
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}
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cursym.Func.Locals = autoffset
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cursym.Func.Args = p.To.Val.(int32)
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/*
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* find leaf subroutines
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*/
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for p := 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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p.Mark |= LEAF
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case ADIV, ADIVU, AMOD, AMODU:
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cursym.Func.Text.Mark &^= LEAF
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case ABL,
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ABX,
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obj.ADUFFZERO,
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obj.ADUFFCOPY:
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cursym.Func.Text.Mark &^= LEAF
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}
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}
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var q2 *obj.Prog
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for p := cursym.Func.Text; p != nil; p = p.Link {
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o := p.As
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switch o {
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case obj.ATEXT:
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autosize = autoffset
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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 += 4
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}
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if autosize == 0 && 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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// are not identified as leaves but still have no frame.
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if ctxt.Debugvlog {
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ctxt.Logf("save suppressed in: %s\n", cursym.Name)
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}
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cursym.Func.Text.Mark |= LEAF
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}
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// FP offsets need an updated p.To.Offset.
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p.To.Offset = int64(autosize) - 4
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if cursym.Func.Text.Mark&LEAF != 0 {
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cursym.Set(obj.AttrLeaf, true)
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if p.From.Sym.NoFrame() {
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break
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}
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}
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if !p.From.Sym.NoSplit() {
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p = c.stacksplit(p, autosize) // emit split check
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}
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// MOVW.W R14,$-autosize(SP)
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p = obj.Appendp(p, c.newprog)
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p.As = AMOVW
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p.Scond |= C_WBIT
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p.From.Type = obj.TYPE_REG
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p.From.Reg = REGLINK
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p.To.Type = obj.TYPE_MEM
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p.To.Offset = int64(-autosize)
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p.To.Reg = REGSP
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p.Spadj = autosize
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if 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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// MOVW g_panic(g), R1
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// CMP $0, R1
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// B.NE checkargp
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// end:
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// NOP
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// ... function ...
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// checkargp:
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// MOVW panic_argp(R1), R2
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// ADD $(autosize+4), R13, R3
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// CMP R2, R3
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// B.NE end
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// ADD $4, R13, R4
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// MOVW R4, panic_argp(R1)
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// B end
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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 an ARM NOP: it encodes to 0 instruction bytes.
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p = obj.Appendp(p, newprog)
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p.As = AMOVW
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p.From.Type = obj.TYPE_MEM
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p.From.Reg = REGG
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p.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REG_R1
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p = obj.Appendp(p, newprog)
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p.As = ACMP
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p.From.Type = obj.TYPE_CONST
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p.From.Offset = 0
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p.Reg = REG_R1
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// B.NE checkargp
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bne := obj.Appendp(p, newprog)
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bne.As = ABNE
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bne.To.Type = obj.TYPE_BRANCH
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// end: NOP
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end := obj.Appendp(bne, newprog)
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end.As = obj.ANOP
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// find end of function
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var last *obj.Prog
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for last = end; last.Link != nil; last = last.Link {
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}
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// MOVW panic_argp(R1), R2
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mov := obj.Appendp(last, newprog)
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mov.As = AMOVW
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mov.From.Type = obj.TYPE_MEM
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mov.From.Reg = REG_R1
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mov.From.Offset = 0 // Panic.argp
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mov.To.Type = obj.TYPE_REG
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mov.To.Reg = REG_R2
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// B.NE branch target is MOVW above
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bne.To.SetTarget(mov)
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// ADD $(autosize+4), R13, R3
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p = obj.Appendp(mov, newprog)
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p.As = AADD
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p.From.Type = obj.TYPE_CONST
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p.From.Offset = int64(autosize) + 4
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p.Reg = REG_R13
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REG_R3
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// CMP R2, R3
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p = obj.Appendp(p, newprog)
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p.As = ACMP
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p.From.Type = obj.TYPE_REG
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p.From.Reg = REG_R2
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p.Reg = REG_R3
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// B.NE end
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p = obj.Appendp(p, newprog)
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p.As = ABNE
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p.To.Type = obj.TYPE_BRANCH
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p.To.SetTarget(end)
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// ADD $4, R13, R4
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p = obj.Appendp(p, newprog)
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p.As = AADD
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p.From.Type = obj.TYPE_CONST
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p.From.Offset = 4
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p.Reg = REG_R13
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REG_R4
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// MOVW R4, panic_argp(R1)
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p = obj.Appendp(p, newprog)
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p.As = AMOVW
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p.From.Type = obj.TYPE_REG
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p.From.Reg = REG_R4
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p.To.Type = obj.TYPE_MEM
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p.To.Reg = REG_R1
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p.To.Offset = 0 // Panic.argp
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// B end
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p = obj.Appendp(p, newprog)
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p.As = AB
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p.To.Type = obj.TYPE_BRANCH
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p.To.SetTarget(end)
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// reset for subsequent passes
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p = end
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}
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case obj.ARET:
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nocache(p)
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if cursym.Func.Text.Mark&LEAF != 0 {
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if autosize == 0 {
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p.As = AB
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p.From = obj.Addr{}
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if p.To.Sym != nil { // retjmp
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p.To.Type = obj.TYPE_BRANCH
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} else {
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p.To.Type = obj.TYPE_MEM
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p.To.Offset = 0
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p.To.Reg = REGLINK
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}
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break
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}
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}
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p.As = AMOVW
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p.Scond |= C_PBIT
|
|
p.From.Type = obj.TYPE_MEM
|
|
p.From.Offset = int64(autosize)
|
|
p.From.Reg = REGSP
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REGPC
|
|
|
|
// If there are instructions following
|
|
// this ARET, they come from a branch
|
|
// with the same stackframe, so no spadj.
|
|
if p.To.Sym != nil { // retjmp
|
|
p.To.Reg = REGLINK
|
|
q2 = obj.Appendp(p, newprog)
|
|
q2.As = AB
|
|
q2.To.Type = obj.TYPE_BRANCH
|
|
q2.To.Sym = p.To.Sym
|
|
p.To.Sym = nil
|
|
p = q2
|
|
}
|
|
|
|
case AADD:
|
|
if p.From.Type == obj.TYPE_CONST && p.From.Reg == 0 && p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP {
|
|
p.Spadj = int32(-p.From.Offset)
|
|
}
|
|
|
|
case ASUB:
|
|
if p.From.Type == obj.TYPE_CONST && p.From.Reg == 0 && p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP {
|
|
p.Spadj = int32(p.From.Offset)
|
|
}
|
|
|
|
case ADIV, ADIVU, AMOD, AMODU:
|
|
if cursym.Func.Text.From.Sym.NoSplit() {
|
|
ctxt.Diag("cannot divide in NOSPLIT function")
|
|
}
|
|
const debugdivmod = false
|
|
if debugdivmod {
|
|
break
|
|
}
|
|
if p.From.Type != obj.TYPE_REG {
|
|
break
|
|
}
|
|
if p.To.Type != obj.TYPE_REG {
|
|
break
|
|
}
|
|
|
|
// Make copy because we overwrite p below.
|
|
q1 := *p
|
|
if q1.Reg == REGTMP || q1.Reg == 0 && q1.To.Reg == REGTMP {
|
|
ctxt.Diag("div already using REGTMP: %v", p)
|
|
}
|
|
|
|
/* MOV m(g),REGTMP */
|
|
p.As = AMOVW
|
|
p.Pos = q1.Pos
|
|
p.From.Type = obj.TYPE_MEM
|
|
p.From.Reg = REGG
|
|
p.From.Offset = 6 * 4 // offset of g.m
|
|
p.Reg = 0
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REGTMP
|
|
|
|
/* MOV a,m_divmod(REGTMP) */
|
|
p = obj.Appendp(p, newprog)
|
|
p.As = AMOVW
|
|
p.Pos = q1.Pos
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = q1.From.Reg
|
|
p.To.Type = obj.TYPE_MEM
|
|
p.To.Reg = REGTMP
|
|
p.To.Offset = 8 * 4 // offset of m.divmod
|
|
|
|
/* MOV b, R8 */
|
|
p = obj.Appendp(p, newprog)
|
|
p.As = AMOVW
|
|
p.Pos = q1.Pos
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = q1.Reg
|
|
if q1.Reg == 0 {
|
|
p.From.Reg = q1.To.Reg
|
|
}
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REG_R8
|
|
p.To.Offset = 0
|
|
|
|
/* CALL appropriate */
|
|
p = obj.Appendp(p, newprog)
|
|
p.As = ABL
|
|
p.Pos = q1.Pos
|
|
p.To.Type = obj.TYPE_BRANCH
|
|
switch o {
|
|
case ADIV:
|
|
p.To.Sym = symdiv
|
|
case ADIVU:
|
|
p.To.Sym = symdivu
|
|
case AMOD:
|
|
p.To.Sym = symmod
|
|
case AMODU:
|
|
p.To.Sym = symmodu
|
|
}
|
|
|
|
/* MOV REGTMP, b */
|
|
p = obj.Appendp(p, newprog)
|
|
p.As = AMOVW
|
|
p.Pos = q1.Pos
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = REGTMP
|
|
p.From.Offset = 0
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = q1.To.Reg
|
|
|
|
case AMOVW:
|
|
if (p.Scond&C_WBIT != 0) && p.To.Type == obj.TYPE_MEM && p.To.Reg == REGSP {
|
|
p.Spadj = int32(-p.To.Offset)
|
|
}
|
|
if (p.Scond&C_PBIT != 0) && p.From.Type == obj.TYPE_MEM && p.From.Reg == REGSP && p.To.Reg != REGPC {
|
|
p.Spadj = int32(-p.From.Offset)
|
|
}
|
|
if p.From.Type == obj.TYPE_ADDR && p.From.Reg == REGSP && p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP {
|
|
p.Spadj = int32(-p.From.Offset)
|
|
}
|
|
|
|
case obj.AGETCALLERPC:
|
|
if cursym.Leaf() {
|
|
/* MOVW LR, Rd */
|
|
p.As = AMOVW
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = REGLINK
|
|
} else {
|
|
/* MOVW (RSP), Rd */
|
|
p.As = AMOVW
|
|
p.From.Type = obj.TYPE_MEM
|
|
p.From.Reg = REGSP
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *ctxt5) stacksplit(p *obj.Prog, framesize int32) *obj.Prog {
|
|
// MOVW g_stackguard(g), R1
|
|
p = obj.Appendp(p, c.newprog)
|
|
|
|
p.As = AMOVW
|
|
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_R1
|
|
|
|
// 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 <= objabi.StackSmall {
|
|
// small stack: SP < stackguard
|
|
// CMP stackguard, SP
|
|
p = obj.Appendp(p, c.newprog)
|
|
|
|
p.As = ACMP
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = REG_R1
|
|
p.Reg = REGSP
|
|
} else if framesize <= objabi.StackBig {
|
|
// large stack: SP-framesize < stackguard-StackSmall
|
|
// MOVW $-(framesize-StackSmall)(SP), R2
|
|
// CMP stackguard, R2
|
|
p = obj.Appendp(p, c.newprog)
|
|
|
|
p.As = AMOVW
|
|
p.From.Type = obj.TYPE_ADDR
|
|
p.From.Reg = REGSP
|
|
p.From.Offset = -(int64(framesize) - objabi.StackSmall)
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REG_R2
|
|
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = ACMP
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = REG_R1
|
|
p.Reg = REG_R2
|
|
} else {
|
|
// Such a large stack we need to protect against wraparound
|
|
// if SP is close to zero.
|
|
// SP-stackguard+StackGuard < framesize + (StackGuard-StackSmall)
|
|
// The +StackGuard on both sides is required to keep the left side positive:
|
|
// SP is allowed to be slightly below stackguard. See stack.h.
|
|
// CMP $StackPreempt, R1
|
|
// MOVW.NE $StackGuard(SP), R2
|
|
// SUB.NE R1, R2
|
|
// MOVW.NE $(framesize+(StackGuard-StackSmall)), R3
|
|
// CMP.NE R3, R2
|
|
p = obj.Appendp(p, c.newprog)
|
|
|
|
p.As = ACMP
|
|
p.From.Type = obj.TYPE_CONST
|
|
p.From.Offset = int64(uint32(objabi.StackPreempt & (1<<32 - 1)))
|
|
p.Reg = REG_R1
|
|
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = AMOVW
|
|
p.From.Type = obj.TYPE_ADDR
|
|
p.From.Reg = REGSP
|
|
p.From.Offset = int64(objabi.StackGuard)
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REG_R2
|
|
p.Scond = C_SCOND_NE
|
|
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = ASUB
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = REG_R1
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REG_R2
|
|
p.Scond = C_SCOND_NE
|
|
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = AMOVW
|
|
p.From.Type = obj.TYPE_ADDR
|
|
p.From.Offset = int64(framesize) + (int64(objabi.StackGuard) - objabi.StackSmall)
|
|
p.To.Type = obj.TYPE_REG
|
|
p.To.Reg = REG_R3
|
|
p.Scond = C_SCOND_NE
|
|
|
|
p = obj.Appendp(p, c.newprog)
|
|
p.As = ACMP
|
|
p.From.Type = obj.TYPE_REG
|
|
p.From.Reg = REG_R3
|
|
p.Reg = REG_R2
|
|
p.Scond = C_SCOND_NE
|
|
}
|
|
|
|
// BLS call-to-morestack
|
|
bls := obj.Appendp(p, c.newprog)
|
|
bls.As = ABLS
|
|
bls.To.Type = obj.TYPE_BRANCH
|
|
|
|
end := c.ctxt.EndUnsafePoint(bls, c.newprog, -1)
|
|
|
|
var last *obj.Prog
|
|
for last = c.cursym.Func.Text; last.Link != nil; last = last.Link {
|
|
}
|
|
|
|
// 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(last, 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)
|
|
|
|
// MOVW LR, R3
|
|
movw := obj.Appendp(pcdata, c.newprog)
|
|
movw.As = AMOVW
|
|
movw.From.Type = obj.TYPE_REG
|
|
movw.From.Reg = REGLINK
|
|
movw.To.Type = obj.TYPE_REG
|
|
movw.To.Reg = REG_R3
|
|
|
|
bls.To.SetTarget(movw)
|
|
|
|
// BL runtime.morestack
|
|
call := obj.Appendp(movw, c.newprog)
|
|
call.As = obj.ACALL
|
|
call.To.Type = obj.TYPE_BRANCH
|
|
morestack := "runtime.morestack"
|
|
switch {
|
|
case c.cursym.CFunc():
|
|
morestack = "runtime.morestackc"
|
|
case !c.cursym.Func.Text.From.Sym.NeedCtxt():
|
|
morestack = "runtime.morestack_noctxt"
|
|
}
|
|
call.To.Sym = c.ctxt.Lookup(morestack)
|
|
|
|
pcdata = c.ctxt.EndUnsafePoint(call, c.newprog, -1)
|
|
|
|
// B start
|
|
b := obj.Appendp(pcdata, c.newprog)
|
|
b.As = obj.AJMP
|
|
b.To.Type = obj.TYPE_BRANCH
|
|
b.To.SetTarget(c.cursym.Func.Text.Link)
|
|
b.Spadj = +framesize
|
|
|
|
return end
|
|
}
|
|
|
|
var unaryDst = map[obj.As]bool{
|
|
ASWI: true,
|
|
AWORD: true,
|
|
}
|
|
|
|
var Linkarm = obj.LinkArch{
|
|
Arch: sys.ArchARM,
|
|
Init: buildop,
|
|
Preprocess: preprocess,
|
|
Assemble: span5,
|
|
Progedit: progedit,
|
|
UnaryDst: unaryDst,
|
|
DWARFRegisters: ARMDWARFRegisters,
|
|
}
|