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cmd/internal/obj: move fields from obj.Link to x86.AsmBuf
These fields are used to encode a single instruction. Add them to AsmBuf, which is also per-instruction, and which is not global. Updates #15756 Change-Id: I0e5ea22ffa641b07291e27de6e2ff23b6dc534bd Reviewed-on: https://go-review.googlesource.com/38668 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This commit is contained in:
Josh Bleecher Snyder
parent
166160b446
commit
4f122e82fe
2 changed files with 49 additions and 48 deletions
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@ -735,11 +735,6 @@ type Link struct {
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Printp *Prog
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Blitrl *Prog
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Elitrl *Prog
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Rexflag int
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Vexflag int
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Rep int
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Repn int
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Lock int
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Instoffset int64
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Autosize int32
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Armsize int32
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@ -2568,10 +2568,16 @@ func oclass(ctxt *obj.Link, p *obj.Prog, a *obj.Addr) int {
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return Yxxx
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}
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// AsmBuf is a simple buffer to assemble variable-length x86 instructions into.
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// AsmBuf is a simple buffer to assemble variable-length x86 instructions into
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// and hold assembly state.
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type AsmBuf struct {
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buf [100]byte
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off int
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rexflag int
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vexflag int
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rep int
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repn int
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lock int
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}
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// Put1 appends one byte to the end of the buffer.
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@ -2828,7 +2834,7 @@ func (asmbuf *AsmBuf) asmandsz(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, a
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switch {
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case int64(int32(a.Offset)) == a.Offset:
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// Offset fits in sign-extended 32 bits.
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case int64(uint32(a.Offset)) == a.Offset && ctxt.Rexflag&Rxw == 0:
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case int64(uint32(a.Offset)) == a.Offset && asmbuf.rexflag&Rxw == 0:
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// Offset fits in zero-extended 32 bits in a 32-bit instruction.
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// This is allowed for assembly that wants to use 32-bit hex
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// constants, e.g. LEAL 0x99999999(AX), AX.
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@ -2856,7 +2862,7 @@ func (asmbuf *AsmBuf) asmandsz(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, a
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goto bad
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}
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asmbuf.Put1(byte(3<<6 | reg[a.Reg]<<0 | r<<3))
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ctxt.Rexflag |= regrex[a.Reg]&(0x40|Rxb) | rex
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asmbuf.rexflag |= regrex[a.Reg]&(0x40|Rxb) | rex
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return
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}
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@ -2887,7 +2893,7 @@ func (asmbuf *AsmBuf) asmandsz(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, a
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base = REG_SP
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}
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ctxt.Rexflag |= regrex[int(a.Index)]&Rxx | regrex[base]&Rxb | rex
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asmbuf.rexflag |= regrex[int(a.Index)]&Rxx | regrex[base]&Rxb | rex
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if base == REG_NONE {
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asmbuf.Put1(byte(0<<6 | 4<<0 | r<<3))
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asmbuf.asmidx(ctxt, int(a.Scale), int(a.Index), base)
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@ -2938,7 +2944,7 @@ func (asmbuf *AsmBuf) asmandsz(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, a
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v = int32(vaddr(ctxt, p, a, &rel))
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}
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ctxt.Rexflag |= regrex[base]&Rxb | rex
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asmbuf.rexflag |= regrex[base]&Rxb | rex
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if base == REG_NONE || (REG_CS <= base && base <= REG_GS) || base == REG_TLS {
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if (a.Sym == nil || !isextern(a.Sym)) && base == REG_NONE && (a.Name == obj.NAME_STATIC || a.Name == obj.NAME_EXTERN || a.Name == obj.NAME_GOTREF) || p.Mode != 64 {
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if a.Name == obj.NAME_GOTREF && (a.Offset != 0 || a.Index != 0 || a.Scale != 0) {
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@ -3271,7 +3277,7 @@ var bpduff2 = []byte{
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// For details about vex prefix see:
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// https://en.wikipedia.org/wiki/VEX_prefix#Technical_description
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func (asmbuf *AsmBuf) asmvex(ctxt *obj.Link, rm, v, r *obj.Addr, vex, opcode uint8) {
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ctxt.Vexflag = 1
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asmbuf.vexflag = 1
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rexR := 0
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if r != nil {
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rexR = regrex[r.Reg] & Rxr
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@ -3389,7 +3395,7 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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asmbuf.Put2(Pe, Pm)
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case Pq3: /* 16 bit escape and opcode escape + REX.W */
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ctxt.Rexflag |= Pw
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asmbuf.rexflag |= Pw
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asmbuf.Put2(Pe, Pm)
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case Pq4: /* 66 0F 38 */
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@ -3403,7 +3409,7 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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asmbuf.Put3(Pe, Pf3, Pm)
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case Pfw: /* xmm opcode escape + REX.W */
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ctxt.Rexflag |= Pw
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asmbuf.rexflag |= Pw
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asmbuf.Put2(Pf3, Pm)
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case Pm: /* opcode escape */
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@ -3416,14 +3422,14 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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if p.Mode != 64 {
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ctxt.Diag("asmins: illegal 64: %v", p)
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}
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ctxt.Rexflag |= Pw
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asmbuf.rexflag |= Pw
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case Pw8: /* 64-bit escape if z >= 8 */
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if z >= 8 {
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if p.Mode != 64 {
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ctxt.Diag("asmins: illegal 64: %v", p)
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}
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ctxt.Rexflag |= Pw
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asmbuf.rexflag |= Pw
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}
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case Pb: /* botch */
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@ -3519,7 +3525,7 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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asmbuf.asmand(ctxt, cursym, p, &p.From, &p.To)
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case Zm_r_xm_nr:
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ctxt.Rexflag = 0
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asmbuf.rexflag = 0
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asmbuf.mediaop(ctxt, o, op, int(yt.zoffset), z)
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asmbuf.asmand(ctxt, cursym, p, &p.From, &p.To)
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@ -3600,7 +3606,7 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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asmbuf.asmand(ctxt, cursym, p, &p.To, &p.From)
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case Zr_m_xm_nr:
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ctxt.Rexflag = 0
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asmbuf.rexflag = 0
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asmbuf.mediaop(ctxt, o, op, int(yt.zoffset), z)
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asmbuf.asmand(ctxt, cursym, p, &p.To, &p.From)
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@ -3647,11 +3653,11 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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asmbuf.Put1(byte(vaddr(ctxt, p, a, nil)))
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case Zib_rp:
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ctxt.Rexflag |= regrex[p.To.Reg] & (Rxb | 0x40)
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asmbuf.rexflag |= regrex[p.To.Reg] & (Rxb | 0x40)
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asmbuf.Put2(byte(op+reg[p.To.Reg]), byte(vaddr(ctxt, p, &p.From, nil)))
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case Zil_rp:
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ctxt.Rexflag |= regrex[p.To.Reg] & Rxb
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asmbuf.rexflag |= regrex[p.To.Reg] & Rxb
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asmbuf.Put1(byte(op + reg[p.To.Reg]))
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if o.prefix == Pe {
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v = vaddr(ctxt, p, &p.From, nil)
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@ -3673,9 +3679,9 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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if l == 0 && rel.Siz != 8 {
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//p->mark |= 0100;
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//print("zero: %llux %v\n", v, p);
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ctxt.Rexflag &^= (0x40 | Rxw)
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asmbuf.rexflag &^= (0x40 | Rxw)
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ctxt.Rexflag |= regrex[p.To.Reg] & Rxb
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asmbuf.rexflag |= regrex[p.To.Reg] & Rxb
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asmbuf.Put1(byte(0xb8 + reg[p.To.Reg]))
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if rel.Type != 0 {
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r = obj.Addrel(cursym)
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@ -3694,7 +3700,7 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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asmbuf.PutInt32(int32(v)) // need all 8
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} else {
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//print("all: %llux %v\n", v, p);
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ctxt.Rexflag |= regrex[p.To.Reg] & Rxb
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asmbuf.rexflag |= regrex[p.To.Reg] & Rxb
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asmbuf.Put1(byte(op + reg[p.To.Reg]))
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if rel.Type != 0 {
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r = obj.Addrel(cursym)
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@ -3752,15 +3758,15 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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}
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case Z_rp:
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ctxt.Rexflag |= regrex[p.To.Reg] & (Rxb | 0x40)
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asmbuf.rexflag |= regrex[p.To.Reg] & (Rxb | 0x40)
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asmbuf.Put1(byte(op + reg[p.To.Reg]))
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case Zrp_:
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ctxt.Rexflag |= regrex[p.From.Reg] & (Rxb | 0x40)
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asmbuf.rexflag |= regrex[p.From.Reg] & (Rxb | 0x40)
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asmbuf.Put1(byte(op + reg[p.From.Reg]))
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case Zclr:
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ctxt.Rexflag &^= Pw
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asmbuf.rexflag &^= Pw
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asmbuf.Put1(byte(op))
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asmbuf.asmand(ctxt, cursym, p, &p.To, &p.To)
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@ -3975,12 +3981,12 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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case 3: /* r,m - 2op */
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asmbuf.Put2(t[0], t[1])
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asmbuf.asmando(ctxt, cursym, p, &p.To, int(t[2]))
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ctxt.Rexflag |= regrex[p.From.Reg] & (Rxr | 0x40)
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asmbuf.rexflag |= regrex[p.From.Reg] & (Rxr | 0x40)
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case 4: /* m,r - 2op */
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asmbuf.Put2(t[0], t[1])
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asmbuf.asmando(ctxt, cursym, p, &p.From, int(t[2]))
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ctxt.Rexflag |= regrex[p.To.Reg] & (Rxr | 0x40)
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asmbuf.rexflag |= regrex[p.To.Reg] & (Rxr | 0x40)
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case 5: /* load full pointer, trash heap */
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if t[0] != 0 {
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@ -4013,7 +4019,7 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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if p.Mode != 64 {
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ctxt.Diag("asmins: illegal 64: %v", p)
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}
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ctxt.Rexflag |= Pw
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asmbuf.rexflag |= Pw
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t = t[1:]
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} else if t[0] == Pe {
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asmbuf.Put1(Pe)
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@ -4147,7 +4153,7 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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// and a R_TLS_IE reloc. This all assumes the only tls variable we access
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// is g, which we can't check here, but will when we assemble the second
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// instruction.
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ctxt.Rexflag = Pw | (regrex[p.To.Reg] & Rxr)
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asmbuf.rexflag = Pw | (regrex[p.To.Reg] & Rxr)
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asmbuf.Put2(0x8B, byte(0x05|(reg[p.To.Reg]<<3)))
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r = obj.Addrel(cursym)
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@ -4167,7 +4173,7 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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pp.From.Sym = ctxt.Plan9privates
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pp.From.Offset = 0
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pp.From.Index = REG_NONE
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ctxt.Rexflag |= Pw
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asmbuf.rexflag |= Pw
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asmbuf.Put1(0x8B)
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asmbuf.asmand(ctxt, cursym, p, &pp.From, &p.To)
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@ -4181,7 +4187,7 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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pp.From.Offset = 0
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pp.From.Index = REG_NONE
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pp.From.Scale = 0
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ctxt.Rexflag |= Pw
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asmbuf.rexflag |= Pw
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asmbuf.Put2(0x64, // FS
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0x8B)
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asmbuf.asmand(ctxt, cursym, p, &pp.From, &p.To)
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@ -4196,7 +4202,7 @@ func (asmbuf *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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pp.From.Offset = 0x28
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pp.From.Index = REG_NONE
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pp.From.Scale = 0
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ctxt.Rexflag |= Pw
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asmbuf.rexflag |= Pw
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asmbuf.Put2(0x65, // GS
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0x8B)
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asmbuf.asmand(ctxt, cursym, p, &pp.From, &p.To)
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@ -4461,17 +4467,17 @@ func (asmbuf *AsmBuf) asmins(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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if ctxt.Headtype == obj.Hnacl && p.Mode == 64 {
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if p.As == AREP {
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ctxt.Rep++
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asmbuf.rep++
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return
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}
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if p.As == AREPN {
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ctxt.Repn++
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asmbuf.repn++
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return
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}
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if p.As == ALOCK {
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ctxt.Lock++
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asmbuf.lock++
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return
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}
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@ -4523,27 +4529,27 @@ func (asmbuf *AsmBuf) asmins(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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asmbuf.Put(naclmovs)
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}
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if ctxt.Rep != 0 {
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if asmbuf.rep != 0 {
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asmbuf.Put1(0xf3)
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ctxt.Rep = 0
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asmbuf.rep = 0
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}
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if ctxt.Repn != 0 {
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if asmbuf.repn != 0 {
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asmbuf.Put1(0xf2)
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ctxt.Repn = 0
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asmbuf.repn = 0
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}
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if ctxt.Lock != 0 {
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if asmbuf.lock != 0 {
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asmbuf.Put1(0xf0)
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ctxt.Lock = 0
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asmbuf.lock = 0
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}
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}
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ctxt.Rexflag = 0
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ctxt.Vexflag = 0
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asmbuf.rexflag = 0
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asmbuf.vexflag = 0
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mark := asmbuf.Len()
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asmbuf.doasm(ctxt, cursym, p)
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if ctxt.Rexflag != 0 && ctxt.Vexflag == 0 {
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if asmbuf.rexflag != 0 && asmbuf.vexflag == 0 {
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/*
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* as befits the whole approach of the architecture,
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* the rex prefix must appear before the first opcode byte
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@ -4562,7 +4568,7 @@ func (asmbuf *AsmBuf) asmins(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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break
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}
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}
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asmbuf.Insert(np, byte(0x40|ctxt.Rexflag))
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asmbuf.Insert(np, byte(0x40|asmbuf.rexflag))
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}
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n := asmbuf.Len()
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@ -4571,7 +4577,7 @@ func (asmbuf *AsmBuf) asmins(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
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if int64(r.Off) < p.Pc {
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break
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}
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if ctxt.Rexflag != 0 {
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if asmbuf.rexflag != 0 {
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r.Off++
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}
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if r.Type == obj.R_PCREL {
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