func nacladdr(ctxt *obj.Link, p *obj.Prog, a *obj.Addr) { if p.As == ALEAL || p.As == ALEAQ { return } if a.Reg == REG_BP { ctxt.Diag("invalid address: %v", p) return } if a.Reg == REG_TLS { a.Reg = REG_BP } if a.Type == obj.TYPE_MEM && a.Name == obj.NAME_NONE { switch a.Reg { // all ok case REG_BP, REG_SP, REG_R15: break default: if a.Index != REG_NONE { ctxt.Diag("invalid address %v", p) } a.Index = a.Reg if a.Index != REG_NONE { a.Scale = 1 } a.Reg = REG_R15 } } }
func initdiv(ctxt *obj.Link) { if ctxt.Sym_div != nil { return } ctxt.Sym_div = obj.Linklookup(ctxt, "_div", 0) ctxt.Sym_divu = obj.Linklookup(ctxt, "_divu", 0) ctxt.Sym_mod = obj.Linklookup(ctxt, "_mod", 0) ctxt.Sym_modu = obj.Linklookup(ctxt, "_modu", 0) }
func follow(ctxt *obj.Link, s *obj.LSym) { ctxt.Cursym = s firstp := ctxt.NewProg() lastp := firstp xfol(ctxt, s.Text, &lastp) lastp.Link = nil s.Text = firstp.Link }
func addnop(ctxt *obj.Link, p *obj.Prog) { q := ctxt.NewProg() // we want to use the canonical NOP (SLL $0,R0,R0) here, // however, as the assembler will always replace $0 // as R0, we have to resort to manually encode the SLL // instruction as WORD $0. q.As = AWORD q.Lineno = p.Lineno q.From.Type = obj.TYPE_CONST q.From.Name = obj.NAME_NONE q.From.Offset = 0 q.Link = p.Link p.Link = q }
func oplook(ctxt *obj.Link, p *obj.Prog) *Optab { if oprange[AOR&obj.AMask] == nil { buildop(ctxt) } a1 := int(p.Optab) if a1 != 0 { return &optab[a1-1] } a1 = int(p.From.Class) if a1 == 0 { a1 = aclass(ctxt, &p.From) + 1 p.From.Class = int8(a1) } a1-- a3 := int(p.To.Class) if a3 == 0 { a3 = aclass(ctxt, &p.To) + 1 p.To.Class = int8(a3) } a3-- a2 := C_NONE if p.Reg != 0 { a2 = C_REG } //print("oplook %P %d %d %d\n", p, a1, a2, a3); ops := oprange[p.As&obj.AMask] c1 := &xcmp[a1] c3 := &xcmp[a3] for i := range ops { op := &ops[i] if int(op.a2) == a2 && c1[op.a1] && c3[op.a3] { p.Optab = uint16(cap(optab) - cap(ops) + i + 1) return op } } ctxt.Diag("illegal combination %v %v %v %v", obj.Aconv(p.As), DRconv(a1), DRconv(a2), DRconv(a3)) prasm(p) if ops == nil { ops = optab } return &ops[0] }
// Rewrite p, if necessary, to access global data via the global offset table. func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog) { if p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO { // ADUFFxxx $offset // becomes // MOVW runtime.duffxxx@GOT, R9 // ADD $offset, R9 // CALL (R9) var sym *obj.LSym if p.As == obj.ADUFFZERO { sym = obj.Linklookup(ctxt, "runtime.duffzero", 0) } else { sym = obj.Linklookup(ctxt, "runtime.duffcopy", 0) } offset := p.To.Offset p.As = AMOVW p.From.Type = obj.TYPE_MEM p.From.Name = obj.NAME_GOTREF p.From.Sym = sym p.To.Type = obj.TYPE_REG p.To.Reg = REG_R9 p.To.Name = obj.NAME_NONE p.To.Offset = 0 p.To.Sym = nil p1 := obj.Appendp(ctxt, p) p1.As = AADD p1.From.Type = obj.TYPE_CONST p1.From.Offset = offset p1.To.Type = obj.TYPE_REG p1.To.Reg = REG_R9 p2 := obj.Appendp(ctxt, p1) p2.As = obj.ACALL p2.To.Type = obj.TYPE_MEM p2.To.Reg = REG_R9 return } // We only care about global data: NAME_EXTERN means a global // symbol in the Go sense, and p.Sym.Local is true for a few // internally defined symbols. if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local { // MOVW $sym, Rx becomes MOVW sym@GOT, Rx // MOVW $sym+<off>, Rx becomes MOVW sym@GOT, Rx; ADD <off>, Rx if p.As != AMOVW { ctxt.Diag("do not know how to handle TYPE_ADDR in %v with -dynlink", p) } if p.To.Type != obj.TYPE_REG { ctxt.Diag("do not know how to handle LEAQ-type insn to non-register in %v with -dynlink", p) } p.From.Type = obj.TYPE_MEM p.From.Name = obj.NAME_GOTREF if p.From.Offset != 0 { q := obj.Appendp(ctxt, p) q.As = AADD q.From.Type = obj.TYPE_CONST q.From.Offset = p.From.Offset q.To = p.To p.From.Offset = 0 } } if p.From3 != nil && p.From3.Name == obj.NAME_EXTERN { ctxt.Diag("don't know how to handle %v with -dynlink", p) } var source *obj.Addr // MOVx sym, Ry becomes MOVW sym@GOT, R9; MOVx (R9), Ry // MOVx Ry, sym becomes MOVW sym@GOT, R9; MOVx Ry, (R9) // An addition may be inserted between the two MOVs if there is an offset. if p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local { if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local { ctxt.Diag("cannot handle NAME_EXTERN on both sides in %v with -dynlink", p) } source = &p.From } else if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local { source = &p.To } else { return } if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ACALL || p.As == obj.ARET || p.As == obj.AJMP { return } if source.Sym.Type == obj.STLSBSS { return } if source.Type != obj.TYPE_MEM { ctxt.Diag("don't know how to handle %v with -dynlink", p) } p1 := obj.Appendp(ctxt, p) p2 := obj.Appendp(ctxt, p1) p1.As = AMOVW p1.From.Type = obj.TYPE_MEM p1.From.Sym = source.Sym p1.From.Name = obj.NAME_GOTREF p1.To.Type = obj.TYPE_REG p1.To.Reg = REG_R9 p2.As = p.As p2.From = p.From p2.To = p.To if p.From.Name == obj.NAME_EXTERN { p2.From.Reg = REG_R9 p2.From.Name = obj.NAME_NONE p2.From.Sym = nil } else if p.To.Name == obj.NAME_EXTERN { p2.To.Reg = REG_R9 p2.To.Name = obj.NAME_NONE p2.To.Sym = nil } else { return } obj.Nopout(p) }
func xfol(ctxt *obj.Link, p *obj.Prog, last **obj.Prog) { var q *obj.Prog var r *obj.Prog var b obj.As for p != nil { a := p.As if a == ABR { q = p.Pcond if (p.Mark&NOSCHED != 0) || q != nil && (q.Mark&NOSCHED != 0) { p.Mark |= FOLL (*last).Link = p *last = p (*last).Pc = pc_cnt pc_cnt += 1 p = p.Link xfol(ctxt, p, last) p = q if p != nil && p.Mark&FOLL == 0 { continue } return } if q != nil { p.Mark |= FOLL p = q if p.Mark&FOLL == 0 { continue } } } if p.Mark&FOLL != 0 { q = p for i := 0; i < 4; i, q = i+1, q.Link { if q == *last || (q.Mark&NOSCHED != 0) { break } b = 0 /* set */ a = q.As if a == obj.ANOP { i-- continue } if a != ABR && a != obj.ARET { if q.Pcond == nil || (q.Pcond.Mark&FOLL != 0) { continue } b = relinv(a) if b == 0 { continue } } for { r = ctxt.NewProg() *r = *p if r.Mark&FOLL == 0 { fmt.Printf("can't happen 1\n") } r.Mark |= FOLL if p != q { p = p.Link (*last).Link = r *last = r (*last).Pc = pc_cnt pc_cnt += 1 continue } (*last).Link = r *last = r (*last).Pc = pc_cnt pc_cnt += 1 if a == ABR || a == obj.ARET { return } r.As = b r.Pcond = p.Link r.Link = p.Pcond if r.Link.Mark&FOLL == 0 { xfol(ctxt, r.Link, last) } if r.Pcond.Mark&FOLL == 0 { fmt.Printf("can't happen 2\n") } return } } a = ABR q = ctxt.NewProg() q.As = a q.Lineno = p.Lineno q.To.Type = obj.TYPE_BRANCH q.To.Offset = p.Pc q.Pcond = p p = q } p.Mark |= FOLL (*last).Link = p *last = p (*last).Pc = pc_cnt pc_cnt += 1 if a == ABR || a == obj.ARET { if p.Mark&NOSCHED != 0 { p = p.Link continue } return } if p.Pcond != nil { if a != ABL && p.Link != nil { xfol(ctxt, p.Link, last) p = p.Pcond if p == nil || (p.Mark&FOLL != 0) { return } continue } } p = p.Link } }
func preprocess(ctxt *obj.Link, cursym *obj.LSym) { // TODO(minux): add morestack short-cuts with small fixed frame-size. ctxt.Cursym = cursym if cursym.Text == nil || cursym.Text.Link == nil { return } p := cursym.Text textstksiz := p.To.Offset if textstksiz == -8 { // Compatibility hack. p.From3.Offset |= obj.NOFRAME textstksiz = 0 } if textstksiz%8 != 0 { ctxt.Diag("frame size %d not a multiple of 8", textstksiz) } if p.From3.Offset&obj.NOFRAME != 0 { if textstksiz != 0 { ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", textstksiz) } } cursym.Args = p.To.Val.(int32) cursym.Locals = int32(textstksiz) /* * find leaf subroutines * strip NOPs * expand RET * expand BECOME pseudo */ if ctxt.Debugvlog != 0 { fmt.Fprintf(ctxt.Bso, "%5.2f noops\n", obj.Cputime()) } ctxt.Bso.Flush() var q *obj.Prog var q1 *obj.Prog for p := cursym.Text; p != nil; p = p.Link { switch p.As { /* too hard, just leave alone */ case obj.ATEXT: q = p p.Mark |= LABEL | LEAF | SYNC if p.Link != nil { p.Link.Mark |= LABEL } case ANOR: q = p if p.To.Type == obj.TYPE_REG { if p.To.Reg == REGZERO { p.Mark |= LABEL | SYNC } } case ASYNC, AWORD: q = p p.Mark |= LABEL | SYNC continue case AMOVW, AMOVWZ, AMOVD: q = p if p.From.Reg >= REG_RESERVED || p.To.Reg >= REG_RESERVED { p.Mark |= LABEL | SYNC } continue case AFABS, AFADD, AFDIV, AFMADD, AFMOVD, AFMOVS, AFMSUB, AFMUL, AFNABS, AFNEG, AFNMADD, AFNMSUB, ALEDBR, ALDEBR, AFSUB: q = p p.Mark |= FLOAT continue case ABL, ABCL, obj.ADUFFZERO, obj.ADUFFCOPY: cursym.Text.Mark &^= LEAF fallthrough case ABC, ABEQ, ABGE, ABGT, ABLE, ABLT, ABNE, ABR, ABVC, ABVS, ACMPBEQ, ACMPBGE, ACMPBGT, ACMPBLE, ACMPBLT, ACMPBNE, ACMPUBEQ, ACMPUBGE, ACMPUBGT, ACMPUBLE, ACMPUBLT, ACMPUBNE: p.Mark |= BRANCH q = p q1 = p.Pcond if q1 != nil { for q1.As == obj.ANOP { q1 = q1.Link p.Pcond = q1 } if q1.Mark&LEAF == 0 { q1.Mark |= LABEL } } else { p.Mark |= LABEL } q1 = p.Link if q1 != nil { q1.Mark |= LABEL } continue case AFCMPO, AFCMPU: q = p p.Mark |= FCMP | FLOAT continue case obj.ARET: q = p if p.Link != nil { p.Link.Mark |= LABEL } continue case obj.ANOP: q1 = p.Link q.Link = q1 /* q is non-nop */ q1.Mark |= p.Mark continue default: q = p continue } } autosize := int32(0) var p1 *obj.Prog var p2 *obj.Prog var pLast *obj.Prog var pPre *obj.Prog var pPreempt *obj.Prog wasSplit := false for p := cursym.Text; p != nil; p = p.Link { pLast = p switch p.As { case obj.ATEXT: autosize = int32(textstksiz) if p.Mark&LEAF != 0 && autosize == 0 && p.From3.Offset&obj.NOFRAME == 0 { // A leaf function with no locals has no frame. p.From3.Offset |= obj.NOFRAME } if p.From3.Offset&obj.NOFRAME == 0 { // If there is a stack frame at all, it includes // space to save the LR. autosize += int32(ctxt.FixedFrameSize()) } p.To.Offset = int64(autosize) q = p if p.From3.Offset&obj.NOSPLIT == 0 { p, pPreempt = stacksplitPre(ctxt, p, autosize) // emit pre part of split check pPre = p wasSplit = true //need post part of split } if autosize != 0 { q = obj.Appendp(ctxt, p) q.As = AMOVD q.From.Type = obj.TYPE_ADDR q.From.Offset = int64(-autosize) q.From.Reg = REGSP // not actually needed - REGSP is assumed if no reg is provided q.To.Type = obj.TYPE_REG q.To.Reg = REGSP q.Spadj = autosize } else if cursym.Text.Mark&LEAF == 0 { // A very few functions that do not return to their caller // (e.g. gogo) are not identified as leaves but still have // no frame. cursym.Text.Mark |= LEAF } if cursym.Text.Mark&LEAF != 0 { cursym.Leaf = true break } q = obj.Appendp(ctxt, q) q.As = AMOVD q.From.Type = obj.TYPE_REG q.From.Reg = REG_LR q.To.Type = obj.TYPE_MEM q.To.Reg = REGSP q.To.Offset = 0 if cursym.Text.From3.Offset&obj.WRAPPER != 0 { // if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame // // MOVD g_panic(g), R3 // CMP R0, R3 // BEQ end // MOVD panic_argp(R3), R4 // ADD $(autosize+8), R1, R5 // CMP R4, R5 // BNE end // ADD $8, R1, R6 // MOVD R6, panic_argp(R3) // end: // NOP // // The NOP is needed to give the jumps somewhere to land. // It is a liblink NOP, not a s390x NOP: it encodes to 0 instruction bytes. q = obj.Appendp(ctxt, q) q.As = AMOVD q.From.Type = obj.TYPE_MEM q.From.Reg = REGG q.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic q.To.Type = obj.TYPE_REG q.To.Reg = REG_R3 q = obj.Appendp(ctxt, q) q.As = ACMP q.From.Type = obj.TYPE_REG q.From.Reg = REG_R0 q.To.Type = obj.TYPE_REG q.To.Reg = REG_R3 q = obj.Appendp(ctxt, q) q.As = ABEQ q.To.Type = obj.TYPE_BRANCH p1 = q q = obj.Appendp(ctxt, q) q.As = AMOVD q.From.Type = obj.TYPE_MEM q.From.Reg = REG_R3 q.From.Offset = 0 // Panic.argp q.To.Type = obj.TYPE_REG q.To.Reg = REG_R4 q = obj.Appendp(ctxt, q) q.As = AADD q.From.Type = obj.TYPE_CONST q.From.Offset = int64(autosize) + ctxt.FixedFrameSize() q.Reg = REGSP q.To.Type = obj.TYPE_REG q.To.Reg = REG_R5 q = obj.Appendp(ctxt, q) q.As = ACMP q.From.Type = obj.TYPE_REG q.From.Reg = REG_R4 q.To.Type = obj.TYPE_REG q.To.Reg = REG_R5 q = obj.Appendp(ctxt, q) q.As = ABNE q.To.Type = obj.TYPE_BRANCH p2 = q q = obj.Appendp(ctxt, q) q.As = AADD q.From.Type = obj.TYPE_CONST q.From.Offset = ctxt.FixedFrameSize() q.Reg = REGSP q.To.Type = obj.TYPE_REG q.To.Reg = REG_R6 q = obj.Appendp(ctxt, q) q.As = AMOVD q.From.Type = obj.TYPE_REG q.From.Reg = REG_R6 q.To.Type = obj.TYPE_MEM q.To.Reg = REG_R3 q.To.Offset = 0 // Panic.argp q = obj.Appendp(ctxt, q) q.As = obj.ANOP p1.Pcond = q p2.Pcond = q } case obj.ARET: if p.From.Type == obj.TYPE_CONST { ctxt.Diag("using BECOME (%v) is not supported!", p) break } retTarget := p.To.Sym if cursym.Text.Mark&LEAF != 0 { if autosize == 0 { 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(ctxt, p) q.As = ABR q.From = obj.Addr{} q.To.Type = obj.TYPE_REG q.To.Reg = REG_LR 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.Type = obj.TYPE_REG p.To.Reg = REG_LR q = p if autosize != 0 { q = obj.Appendp(ctxt, q) 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(ctxt, q) 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) } } } if wasSplit { pLast = stacksplitPost(ctxt, pLast, pPre, pPreempt) // emit post part of split check } }
// Rewrite p, if necessary, to access global data via the global offset table. func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog) { // At the moment EXRL instructions are not emitted by the compiler and only reference local symbols in // assembly code. if p.As == AEXRL { return } // We only care about global data: NAME_EXTERN means a global // symbol in the Go sense, and p.Sym.Local is true for a few // internally defined symbols. if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local { // MOVD $sym, Rx becomes MOVD sym@GOT, Rx // MOVD $sym+<off>, Rx becomes MOVD sym@GOT, Rx; ADD <off>, Rx if p.To.Type != obj.TYPE_REG || p.As != AMOVD { ctxt.Diag("do not know how to handle LEA-type insn to non-register in %v with -dynlink", p) } p.From.Type = obj.TYPE_MEM p.From.Name = obj.NAME_GOTREF q := p if p.From.Offset != 0 { q = obj.Appendp(ctxt, p) q.As = AADD q.From.Type = obj.TYPE_CONST q.From.Offset = p.From.Offset q.To = p.To p.From.Offset = 0 } } if p.From3 != nil && p.From3.Name == obj.NAME_EXTERN { ctxt.Diag("don't know how to handle %v with -dynlink", p) } var source *obj.Addr // MOVD sym, Ry becomes MOVD sym@GOT, REGTMP; MOVD (REGTMP), Ry // MOVD Ry, sym becomes MOVD sym@GOT, REGTMP; MOVD Ry, (REGTMP) // An addition may be inserted between the two MOVs if there is an offset. if p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local { if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local { ctxt.Diag("cannot handle NAME_EXTERN on both sides in %v with -dynlink", p) } source = &p.From } else if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local { source = &p.To } else { return } if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ACALL || p.As == obj.ARET || p.As == obj.AJMP { return } if source.Sym.Type == obj.STLSBSS { return } if source.Type != obj.TYPE_MEM { ctxt.Diag("don't know how to handle %v with -dynlink", p) } p1 := obj.Appendp(ctxt, p) p2 := obj.Appendp(ctxt, p1) p1.As = AMOVD p1.From.Type = obj.TYPE_MEM p1.From.Sym = source.Sym p1.From.Name = obj.NAME_GOTREF p1.To.Type = obj.TYPE_REG p1.To.Reg = REGTMP p2.As = p.As p2.From = p.From p2.To = p.To if p.From.Name == obj.NAME_EXTERN { p2.From.Reg = REGTMP p2.From.Name = obj.NAME_NONE p2.From.Sym = nil } else if p.To.Name == obj.NAME_EXTERN { p2.To.Reg = REGTMP p2.To.Name = obj.NAME_NONE p2.To.Sym = nil } else { return } obj.Nopout(p) }
func preprocess(ctxt *obj.Link, cursym *obj.LSym) { ctxt.Cursym = cursym if cursym.Text == nil || cursym.Text.Link == nil { return } p := cursym.Text textstksiz := p.To.Offset aoffset := int32(textstksiz) cursym.Args = p.To.Val.(int32) cursym.Locals = int32(textstksiz) /* * find leaf subroutines * strip NOPs * expand RET */ ctxt.Bso.Flush() q := (*obj.Prog)(nil) var q1 *obj.Prog for p := cursym.Text; p != nil; p = p.Link { switch p.As { case obj.ATEXT: p.Mark |= LEAF case obj.ARET: break case obj.ANOP: q1 = p.Link q.Link = q1 /* q is non-nop */ q1.Mark |= p.Mark continue case ABL, obj.ADUFFZERO, obj.ADUFFCOPY: cursym.Text.Mark &^= LEAF fallthrough case ACBNZ, ACBZ, ACBNZW, ACBZW, ATBZ, ATBNZ, AB, ABEQ, ABNE, ABCS, ABHS, ABCC, ABLO, ABMI, ABPL, ABVS, ABVC, ABHI, ABLS, ABGE, ABLT, ABGT, ABLE, AADR, /* strange */ AADRP: q1 = p.Pcond if q1 != nil { for q1.As == obj.ANOP { q1 = q1.Link p.Pcond = q1 } } break } q = p } var q2 *obj.Prog var retjmp *obj.LSym for p := cursym.Text; p != nil; p = p.Link { o := p.As switch o { case obj.ATEXT: cursym.Text = p if textstksiz < 0 { ctxt.Autosize = 0 } else { ctxt.Autosize = int32(textstksiz + 8) } if (cursym.Text.Mark&LEAF != 0) && ctxt.Autosize <= 8 { ctxt.Autosize = 0 } else if ctxt.Autosize&(16-1) != 0 { // The frame includes an LR. // If the frame size is 8, it's only an LR, // so there's no potential for breaking references to // local variables by growing the frame size, // because there are no local variables. // But otherwise, if there is a non-empty locals section, // the author of the code is responsible for making sure // that the frame size is 8 mod 16. if ctxt.Autosize == 8 { ctxt.Autosize += 8 cursym.Locals += 8 } else { ctxt.Diag("%v: unaligned frame size %d - must be 8 mod 16 (or 0)", p, ctxt.Autosize-8) } } p.To.Offset = int64(ctxt.Autosize) - 8 if ctxt.Autosize == 0 && !(cursym.Text.Mark&LEAF != 0) { if ctxt.Debugvlog != 0 { fmt.Fprintf(ctxt.Bso, "save suppressed in: %s\n", cursym.Text.From.Sym.Name) } ctxt.Bso.Flush() cursym.Text.Mark |= LEAF } if !(p.From3.Offset&obj.NOSPLIT != 0) { p = stacksplit(ctxt, p, ctxt.Autosize) // emit split check } aoffset = ctxt.Autosize if aoffset > 0xF0 { aoffset = 0xF0 } if cursym.Text.Mark&LEAF != 0 { cursym.Leaf = true if ctxt.Autosize == 0 { break } aoffset = 0 } q = p if ctxt.Autosize > aoffset { q = ctxt.NewProg() q.As = ASUB q.Lineno = p.Lineno q.From.Type = obj.TYPE_CONST q.From.Offset = int64(ctxt.Autosize) - int64(aoffset) q.To.Type = obj.TYPE_REG q.To.Reg = REGSP q.Spadj = int32(q.From.Offset) q.Link = p.Link p.Link = q if cursym.Text.Mark&LEAF != 0 { break } } q1 = ctxt.NewProg() q1.As = AMOVD q1.Lineno = p.Lineno q1.From.Type = obj.TYPE_REG q1.From.Reg = REGLINK q1.To.Type = obj.TYPE_MEM q1.Scond = C_XPRE q1.To.Offset = int64(-aoffset) q1.To.Reg = REGSP q1.Link = q.Link q1.Spadj = aoffset q.Link = q1 if cursym.Text.From3.Offset&obj.WRAPPER != 0 { // if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame // // MOV g_panic(g), R1 // CMP ZR, R1 // BEQ end // MOV panic_argp(R1), R2 // ADD $(autosize+8), RSP, R3 // CMP R2, R3 // BNE end // ADD $8, RSP, R4 // MOVD R4, panic_argp(R1) // end: // NOP // // The NOP is needed to give the jumps somewhere to land. // It is a liblink NOP, not a ARM64 NOP: it encodes to 0 instruction bytes. q = q1 q = obj.Appendp(ctxt, q) q.As = AMOVD q.From.Type = obj.TYPE_MEM q.From.Reg = REGG q.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic q.To.Type = obj.TYPE_REG q.To.Reg = REG_R1 q = obj.Appendp(ctxt, q) q.As = ACMP q.From.Type = obj.TYPE_REG q.From.Reg = REGZERO q.Reg = REG_R1 q = obj.Appendp(ctxt, q) q.As = ABEQ q.To.Type = obj.TYPE_BRANCH q1 = q q = obj.Appendp(ctxt, q) q.As = AMOVD q.From.Type = obj.TYPE_MEM q.From.Reg = REG_R1 q.From.Offset = 0 // Panic.argp q.To.Type = obj.TYPE_REG q.To.Reg = REG_R2 q = obj.Appendp(ctxt, q) q.As = AADD q.From.Type = obj.TYPE_CONST q.From.Offset = int64(ctxt.Autosize) + 8 q.Reg = REGSP q.To.Type = obj.TYPE_REG q.To.Reg = REG_R3 q = obj.Appendp(ctxt, q) q.As = ACMP q.From.Type = obj.TYPE_REG q.From.Reg = REG_R2 q.Reg = REG_R3 q = obj.Appendp(ctxt, q) q.As = ABNE q.To.Type = obj.TYPE_BRANCH q2 = q q = obj.Appendp(ctxt, q) q.As = AADD q.From.Type = obj.TYPE_CONST q.From.Offset = 8 q.Reg = REGSP q.To.Type = obj.TYPE_REG q.To.Reg = REG_R4 q = obj.Appendp(ctxt, q) q.As = AMOVD q.From.Type = obj.TYPE_REG q.From.Reg = REG_R4 q.To.Type = obj.TYPE_MEM q.To.Reg = REG_R1 q.To.Offset = 0 // Panic.argp q = obj.Appendp(ctxt, q) q.As = obj.ANOP q1.Pcond = q q2.Pcond = q } case obj.ARET: nocache(p) if p.From.Type == obj.TYPE_CONST { ctxt.Diag("using BECOME (%v) is not supported!", p) break } retjmp = p.To.Sym p.To = obj.Addr{} if cursym.Text.Mark&LEAF != 0 { if ctxt.Autosize != 0 { p.As = AADD p.From.Type = obj.TYPE_CONST p.From.Offset = int64(ctxt.Autosize) p.To.Type = obj.TYPE_REG p.To.Reg = REGSP p.Spadj = -ctxt.Autosize } } else { /* want write-back pre-indexed SP+autosize -> SP, loading REGLINK*/ aoffset = ctxt.Autosize if aoffset > 0xF0 { aoffset = 0xF0 } p.As = AMOVD p.From.Type = obj.TYPE_MEM p.Scond = C_XPOST p.From.Offset = int64(aoffset) p.From.Reg = REGSP p.To.Type = obj.TYPE_REG p.To.Reg = REGLINK p.Spadj = -aoffset if ctxt.Autosize > aoffset { q = ctxt.NewProg() q.As = AADD q.From.Type = obj.TYPE_CONST q.From.Offset = int64(ctxt.Autosize) - int64(aoffset) q.To.Type = obj.TYPE_REG q.To.Reg = REGSP q.Link = p.Link q.Spadj = int32(-q.From.Offset) q.Lineno = p.Lineno p.Link = q p = q } } if p.As != obj.ARET { q = ctxt.NewProg() q.Lineno = p.Lineno q.Link = p.Link p.Link = q p = q } if retjmp != nil { // retjmp p.As = AB p.To.Type = obj.TYPE_BRANCH p.To.Sym = retjmp p.Spadj = +ctxt.Autosize break } p.As = obj.ARET p.To.Type = obj.TYPE_MEM p.To.Offset = 0 p.To.Reg = REGLINK p.Spadj = +ctxt.Autosize case AADD, ASUB: if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.From.Type == obj.TYPE_CONST { if p.As == AADD { p.Spadj = int32(-p.From.Offset) } else { p.Spadj = int32(+p.From.Offset) } } break } } }
func progedit(ctxt *obj.Link, p *obj.Prog) { // Maintain information about code generation mode. if ctxt.Mode == 0 { ctxt.Mode = ctxt.Arch.RegSize * 8 } p.Mode = int8(ctxt.Mode) switch p.As { case AMODE: if p.From.Type == obj.TYPE_CONST || (p.From.Type == obj.TYPE_MEM && p.From.Reg == REG_NONE) { switch int(p.From.Offset) { case 16, 32, 64: ctxt.Mode = int(p.From.Offset) } } obj.Nopout(p) } // Thread-local storage references use the TLS pseudo-register. // As a register, TLS refers to the thread-local storage base, and it // can only be loaded into another register: // // MOVQ TLS, AX // // An offset from the thread-local storage base is written off(reg)(TLS*1). // Semantically it is off(reg), but the (TLS*1) annotation marks this as // indexing from the loaded TLS base. This emits a relocation so that // if the linker needs to adjust the offset, it can. For example: // // MOVQ TLS, AX // MOVQ 0(AX)(TLS*1), CX // load g into CX // // On systems that support direct access to the TLS memory, this // pair of instructions can be reduced to a direct TLS memory reference: // // MOVQ 0(TLS), CX // load g into CX // // The 2-instruction and 1-instruction forms correspond to the two code // sequences for loading a TLS variable in the local exec model given in "ELF // Handling For Thread-Local Storage". // // We apply this rewrite on systems that support the 1-instruction form. // The decision is made using only the operating system and the -shared flag, // not the link mode. If some link modes on a particular operating system // require the 2-instruction form, then all builds for that operating system // will use the 2-instruction form, so that the link mode decision can be // delayed to link time. // // In this way, all supported systems use identical instructions to // access TLS, and they are rewritten appropriately first here in // liblink and then finally using relocations in the linker. // // When -shared is passed, we leave the code in the 2-instruction form but // assemble (and relocate) them in different ways to generate the initial // exec code sequence. It's a bit of a fluke that this is possible without // rewriting the instructions more comprehensively, and it only does because // we only support a single TLS variable (g). if CanUse1InsnTLS(ctxt) { // Reduce 2-instruction sequence to 1-instruction sequence. // Sequences like // MOVQ TLS, BX // ... off(BX)(TLS*1) ... // become // NOP // ... off(TLS) ... // // TODO(rsc): Remove the Hsolaris special case. It exists only to // guarantee we are producing byte-identical binaries as before this code. // But it should be unnecessary. if (p.As == AMOVQ || p.As == AMOVL) && p.From.Type == obj.TYPE_REG && p.From.Reg == REG_TLS && p.To.Type == obj.TYPE_REG && REG_AX <= p.To.Reg && p.To.Reg <= REG_R15 && ctxt.Headtype != obj.Hsolaris { obj.Nopout(p) } if p.From.Type == obj.TYPE_MEM && p.From.Index == REG_TLS && REG_AX <= p.From.Reg && p.From.Reg <= REG_R15 { p.From.Reg = REG_TLS p.From.Scale = 0 p.From.Index = REG_NONE } if p.To.Type == obj.TYPE_MEM && p.To.Index == REG_TLS && REG_AX <= p.To.Reg && p.To.Reg <= REG_R15 { p.To.Reg = REG_TLS p.To.Scale = 0 p.To.Index = REG_NONE } } else { // load_g_cx, below, always inserts the 1-instruction sequence. Rewrite it // as the 2-instruction sequence if necessary. // MOVQ 0(TLS), BX // becomes // MOVQ TLS, BX // MOVQ 0(BX)(TLS*1), BX if (p.As == AMOVQ || p.As == AMOVL) && p.From.Type == obj.TYPE_MEM && p.From.Reg == REG_TLS && p.To.Type == obj.TYPE_REG && REG_AX <= p.To.Reg && p.To.Reg <= REG_R15 { q := obj.Appendp(ctxt, p) q.As = p.As q.From = p.From q.From.Type = obj.TYPE_MEM q.From.Reg = p.To.Reg q.From.Index = REG_TLS q.From.Scale = 2 // TODO: use 1 q.To = p.To p.From.Type = obj.TYPE_REG p.From.Reg = REG_TLS p.From.Index = REG_NONE p.From.Offset = 0 } } // TODO: Remove. if ctxt.Headtype == obj.Hwindows && p.Mode == 64 || ctxt.Headtype == obj.Hplan9 { if p.From.Scale == 1 && p.From.Index == REG_TLS { p.From.Scale = 2 } if p.To.Scale == 1 && p.To.Index == REG_TLS { p.To.Scale = 2 } } // Rewrite 0 to $0 in 3rd argument to CMPPS etc. // That's what the tables expect. switch p.As { case ACMPPD, ACMPPS, ACMPSD, ACMPSS: if p.To.Type == obj.TYPE_MEM && p.To.Name == obj.NAME_NONE && p.To.Reg == REG_NONE && p.To.Index == REG_NONE && p.To.Sym == nil { p.To.Type = obj.TYPE_CONST } } // Rewrite CALL/JMP/RET to symbol as TYPE_BRANCH. switch p.As { case obj.ACALL, obj.AJMP, obj.ARET: if p.To.Type == obj.TYPE_MEM && (p.To.Name == obj.NAME_EXTERN || p.To.Name == obj.NAME_STATIC) && p.To.Sym != nil { p.To.Type = obj.TYPE_BRANCH } } // Rewrite MOVL/MOVQ $XXX(FP/SP) as LEAL/LEAQ. if p.From.Type == obj.TYPE_ADDR && (ctxt.Arch.Family == sys.AMD64 || p.From.Name != obj.NAME_EXTERN && p.From.Name != obj.NAME_STATIC) { switch p.As { case AMOVL: p.As = ALEAL p.From.Type = obj.TYPE_MEM case AMOVQ: p.As = ALEAQ p.From.Type = obj.TYPE_MEM } } if ctxt.Headtype == obj.Hnacl && p.Mode == 64 { if p.From3 != nil { nacladdr(ctxt, p, p.From3) } nacladdr(ctxt, p, &p.From) nacladdr(ctxt, p, &p.To) } // Rewrite float constants to values stored in memory. switch p.As { // Convert AMOVSS $(0), Xx to AXORPS Xx, Xx case AMOVSS: if p.From.Type == obj.TYPE_FCONST { // f == 0 can't be used here due to -0, so use Float64bits if f := p.From.Val.(float64); math.Float64bits(f) == 0 { if p.To.Type == obj.TYPE_REG && REG_X0 <= p.To.Reg && p.To.Reg <= REG_X15 { p.As = AXORPS p.From = p.To break } } } fallthrough case AFMOVF, AFADDF, AFSUBF, AFSUBRF, AFMULF, AFDIVF, AFDIVRF, AFCOMF, AFCOMFP, AADDSS, ASUBSS, AMULSS, ADIVSS, ACOMISS, AUCOMISS: if p.From.Type == obj.TYPE_FCONST { f32 := float32(p.From.Val.(float64)) i32 := math.Float32bits(f32) literal := fmt.Sprintf("$f32.%08x", i32) s := obj.Linklookup(ctxt, literal, 0) p.From.Type = obj.TYPE_MEM p.From.Name = obj.NAME_EXTERN p.From.Sym = s p.From.Sym.Local = true p.From.Offset = 0 } case AMOVSD: // Convert AMOVSD $(0), Xx to AXORPS Xx, Xx if p.From.Type == obj.TYPE_FCONST { // f == 0 can't be used here due to -0, so use Float64bits if f := p.From.Val.(float64); math.Float64bits(f) == 0 { if p.To.Type == obj.TYPE_REG && REG_X0 <= p.To.Reg && p.To.Reg <= REG_X15 { p.As = AXORPS p.From = p.To break } } } fallthrough case AFMOVD, AFADDD, AFSUBD, AFSUBRD, AFMULD, AFDIVD, AFDIVRD, AFCOMD, AFCOMDP, AADDSD, ASUBSD, AMULSD, ADIVSD, ACOMISD, AUCOMISD: if p.From.Type == obj.TYPE_FCONST { i64 := math.Float64bits(p.From.Val.(float64)) literal := fmt.Sprintf("$f64.%016x", i64) s := obj.Linklookup(ctxt, literal, 0) p.From.Type = obj.TYPE_MEM p.From.Name = obj.NAME_EXTERN p.From.Sym = s p.From.Sym.Local = true p.From.Offset = 0 } } if ctxt.Flag_dynlink { rewriteToUseGot(ctxt, p) } if ctxt.Flag_shared && p.Mode == 32 { rewriteToPcrel(ctxt, p) } }
func span0(ctxt *obj.Link, cursym *obj.LSym) { p := cursym.Text if p == nil || p.Link == nil { // handle external functions and ELF section symbols return } ctxt.Cursym = cursym ctxt.Autosize = int32(p.To.Offset + 8) if oprange[AOR&obj.AMask] == nil { buildop(ctxt) } c := int64(0) p.Pc = c var m int var o *Optab for p = p.Link; p != nil; p = p.Link { ctxt.Curp = p p.Pc = c o = oplook(ctxt, p) m = int(o.size) if m == 0 { if p.As != obj.ANOP && p.As != obj.AFUNCDATA && p.As != obj.APCDATA && p.As != obj.AUSEFIELD { ctxt.Diag("zero-width instruction\n%v", p) } continue } c += int64(m) } cursym.Size = c /* * if any procedure is large enough to * generate a large SBRA branch, then * generate extra passes putting branches * around jmps to fix. this is rare. */ bflag := 1 var otxt int64 var q *obj.Prog for bflag != 0 { if ctxt.Debugvlog != 0 { fmt.Fprintf(ctxt.Bso, "%5.2f span1\n", obj.Cputime()) } bflag = 0 c = 0 for p = cursym.Text.Link; p != nil; p = p.Link { p.Pc = c o = oplook(ctxt, p) // very large conditional branches if o.type_ == 6 && p.Pcond != nil { otxt = p.Pcond.Pc - c if otxt < -(1<<17)+10 || otxt >= (1<<17)-10 { q = ctxt.NewProg() q.Link = p.Link p.Link = q q.As = AJMP q.Lineno = p.Lineno q.To.Type = obj.TYPE_BRANCH q.Pcond = p.Pcond p.Pcond = q q = ctxt.NewProg() q.Link = p.Link p.Link = q q.As = AJMP q.Lineno = p.Lineno q.To.Type = obj.TYPE_BRANCH q.Pcond = q.Link.Link addnop(ctxt, p.Link) addnop(ctxt, p) bflag = 1 } } m = int(o.size) if m == 0 { if p.As != obj.ANOP && p.As != obj.AFUNCDATA && p.As != obj.APCDATA && p.As != obj.AUSEFIELD { ctxt.Diag("zero-width instruction\n%v", p) } continue } c += int64(m) } cursym.Size = c } c += -c & (FuncAlign - 1) cursym.Size = c /* * lay out the code, emitting code and data relocations. */ cursym.Grow(cursym.Size) bp := cursym.P var i int32 var out [4]uint32 for p := cursym.Text.Link; p != nil; p = p.Link { ctxt.Pc = p.Pc ctxt.Curp = p o = oplook(ctxt, p) if int(o.size) > 4*len(out) { log.Fatalf("out array in span0 is too small, need at least %d for %v", o.size/4, p) } asmout(ctxt, p, o, out[:]) for i = 0; i < int32(o.size/4); i++ { ctxt.Arch.ByteOrder.PutUint32(bp, out[i]) bp = bp[4:] } } }
func softfloat(ctxt *obj.Link, cursym *obj.LSym) { if ctxt.Goarm > 5 { return } symsfloat := obj.Linklookup(ctxt, "_sfloat", 0) wasfloat := 0 for p := cursym.Text; p != nil; p = p.Link { if p.Pcond != nil { p.Pcond.Mark |= LABEL } } var next *obj.Prog for p := cursym.Text; p != nil; p = p.Link { switch p.As { case AMOVW: if isfloatreg(&p.To) || isfloatreg(&p.From) { goto soft } goto notsoft case AMOVWD, AMOVWF, AMOVDW, AMOVFW, AMOVFD, AMOVDF, AMOVF, AMOVD, ACMPF, ACMPD, AADDF, AADDD, ASUBF, ASUBD, AMULF, AMULD, ADIVF, ADIVD, ASQRTF, ASQRTD, AABSF, AABSD: goto soft default: goto notsoft } soft: if wasfloat == 0 || (p.Mark&LABEL != 0) { next = ctxt.NewProg() *next = *p // BL _sfloat(SB) *p = obj.Prog{} p.Ctxt = ctxt p.Link = next p.As = ABL p.To.Type = obj.TYPE_BRANCH p.To.Sym = symsfloat p.Lineno = next.Lineno p = next wasfloat = 1 } continue notsoft: wasfloat = 0 } }
func preprocess(ctxt *obj.Link, cursym *obj.LSym) { // TODO(minux): add morestack short-cuts with small fixed frame-size. ctxt.Cursym = cursym if cursym.Text == nil || cursym.Text.Link == nil { return } p := cursym.Text textstksiz := p.To.Offset if textstksiz == -8 { // Compatibility hack. p.From3.Offset |= obj.NOFRAME textstksiz = 0 } if textstksiz%8 != 0 { ctxt.Diag("frame size %d not a multiple of 8", textstksiz) } if p.From3.Offset&obj.NOFRAME != 0 { if textstksiz != 0 { ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", textstksiz) } } cursym.Args = p.To.Val.(int32) cursym.Locals = int32(textstksiz) /* * find leaf subroutines * strip NOPs * expand RET * expand BECOME pseudo */ if ctxt.Debugvlog != 0 { fmt.Fprintf(ctxt.Bso, "%5.2f noops\n", obj.Cputime()) } ctxt.Bso.Flush() var q *obj.Prog var q1 *obj.Prog for p := cursym.Text; p != nil; p = p.Link { switch p.As { /* too hard, just leave alone */ case obj.ATEXT: q = p p.Mark |= LABEL | LEAF | SYNC if p.Link != nil { p.Link.Mark |= LABEL } case ANOR: q = p if p.To.Type == obj.TYPE_REG { if p.To.Reg == REGZERO { p.Mark |= LABEL | SYNC } } case ALWAR, ALBAR, ASTBCCC, ASTWCCC, AECIWX, AECOWX, AEIEIO, AICBI, AISYNC, ATLBIE, ATLBIEL, ASLBIA, ASLBIE, ASLBMFEE, ASLBMFEV, ASLBMTE, ADCBF, ADCBI, ADCBST, ADCBT, ADCBTST, ADCBZ, ASYNC, ATLBSYNC, APTESYNC, ALWSYNC, ATW, AWORD, ARFI, ARFCI, ARFID, AHRFID: q = p p.Mark |= LABEL | SYNC continue case AMOVW, AMOVWZ, AMOVD: q = p if p.From.Reg >= REG_SPECIAL || p.To.Reg >= REG_SPECIAL { p.Mark |= LABEL | SYNC } continue case AFABS, AFABSCC, AFADD, AFADDCC, AFCTIW, AFCTIWCC, AFCTIWZ, AFCTIWZCC, AFDIV, AFDIVCC, AFMADD, AFMADDCC, AFMOVD, AFMOVDU, /* case AFMOVDS: */ AFMOVS, AFMOVSU, /* case AFMOVSD: */ AFMSUB, AFMSUBCC, AFMUL, AFMULCC, AFNABS, AFNABSCC, AFNEG, AFNEGCC, AFNMADD, AFNMADDCC, AFNMSUB, AFNMSUBCC, AFRSP, AFRSPCC, AFSUB, AFSUBCC: q = p p.Mark |= FLOAT continue case ABL, ABCL, obj.ADUFFZERO, obj.ADUFFCOPY: cursym.Text.Mark &^= LEAF fallthrough case ABC, ABEQ, ABGE, ABGT, ABLE, ABLT, ABNE, ABR, ABVC, ABVS: p.Mark |= BRANCH q = p q1 = p.Pcond if q1 != nil { for q1.As == obj.ANOP { q1 = q1.Link p.Pcond = q1 } if q1.Mark&LEAF == 0 { q1.Mark |= LABEL } } else { p.Mark |= LABEL } q1 = p.Link if q1 != nil { q1.Mark |= LABEL } continue case AFCMPO, AFCMPU: q = p p.Mark |= FCMP | FLOAT continue case obj.ARET: q = p if p.Link != nil { p.Link.Mark |= LABEL } continue case obj.ANOP: q1 = p.Link q.Link = q1 /* q is non-nop */ q1.Mark |= p.Mark continue default: q = p continue } } autosize := int32(0) var aoffset int var mov obj.As var p1 *obj.Prog var p2 *obj.Prog for p := cursym.Text; p != nil; p = p.Link { o := p.As switch o { case obj.ATEXT: mov = AMOVD aoffset = 0 autosize = int32(textstksiz) if p.Mark&LEAF != 0 && autosize == 0 && p.From3.Offset&obj.NOFRAME == 0 { // A leaf function with no locals has no frame. p.From3.Offset |= obj.NOFRAME } if p.From3.Offset&obj.NOFRAME == 0 { // If there is a stack frame at all, it includes // space to save the LR. autosize += int32(ctxt.FixedFrameSize()) } p.To.Offset = int64(autosize) q = p if ctxt.Flag_shared && cursym.Name != "runtime.duffzero" && cursym.Name != "runtime.duffcopy" && cursym.Name != "runtime.stackBarrier" { // When compiling Go into PIC, all functions must start // with instructions to load the TOC pointer into r2: // // addis r2, r12, .TOC.-func@ha // addi r2, r2, .TOC.-func@l+4 // // We could probably skip this prologue in some situations // but it's a bit subtle. However, it is both safe and // necessary to leave the prologue off duffzero and // duffcopy as we rely on being able to jump to a specific // instruction offset for them, and stackBarrier is only // ever called from an overwritten LR-save slot on the // stack (when r12 will not be remotely the right thing) // but fortunately does not access global data. // // These are AWORDS because there is no (afaict) way to // generate the addis instruction except as part of the // load of a large constant, and in that case there is no // way to use r12 as the source. q = obj.Appendp(ctxt, q) q.As = AWORD q.Lineno = p.Lineno q.From.Type = obj.TYPE_CONST q.From.Offset = 0x3c4c0000 q = obj.Appendp(ctxt, q) q.As = AWORD q.Lineno = p.Lineno q.From.Type = obj.TYPE_CONST q.From.Offset = 0x38420000 rel := obj.Addrel(ctxt.Cursym) rel.Off = 0 rel.Siz = 8 rel.Sym = obj.Linklookup(ctxt, ".TOC.", 0) rel.Type = obj.R_ADDRPOWER_PCREL } if cursym.Text.From3.Offset&obj.NOSPLIT == 0 { q = stacksplit(ctxt, q, autosize) // emit split check } if autosize != 0 { /* use MOVDU to adjust R1 when saving R31, if autosize is small */ if cursym.Text.Mark&LEAF == 0 && autosize >= -BIG && autosize <= BIG { mov = AMOVDU aoffset = int(-autosize) } else { q = obj.Appendp(ctxt, q) q.As = AADD q.Lineno = p.Lineno q.From.Type = obj.TYPE_CONST q.From.Offset = int64(-autosize) q.To.Type = obj.TYPE_REG q.To.Reg = REGSP q.Spadj = +autosize } } else if cursym.Text.Mark&LEAF == 0 { // A very few functions that do not return to their caller // (e.g. gogo) are not identified as leaves but still have // no frame. cursym.Text.Mark |= LEAF } if cursym.Text.Mark&LEAF != 0 { cursym.Leaf = true break } q = obj.Appendp(ctxt, q) q.As = AMOVD q.Lineno = p.Lineno q.From.Type = obj.TYPE_REG q.From.Reg = REG_LR q.To.Type = obj.TYPE_REG q.To.Reg = REGTMP q = obj.Appendp(ctxt, q) q.As = mov q.Lineno = p.Lineno q.From.Type = obj.TYPE_REG q.From.Reg = REGTMP q.To.Type = obj.TYPE_MEM q.To.Offset = int64(aoffset) q.To.Reg = REGSP if q.As == AMOVDU { q.Spadj = int32(-aoffset) } if ctxt.Flag_shared { q = obj.Appendp(ctxt, q) q.As = AMOVD q.Lineno = p.Lineno q.From.Type = obj.TYPE_REG q.From.Reg = REG_R2 q.To.Type = obj.TYPE_MEM q.To.Reg = REGSP q.To.Offset = 24 } if cursym.Text.From3.Offset&obj.WRAPPER != 0 { // if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame // // MOVD g_panic(g), R3 // CMP R0, R3 // BEQ end // MOVD panic_argp(R3), R4 // ADD $(autosize+8), R1, R5 // CMP R4, R5 // BNE end // ADD $8, R1, R6 // MOVD R6, panic_argp(R3) // end: // NOP // // The NOP is needed to give the jumps somewhere to land. // It is a liblink NOP, not a ppc64 NOP: it encodes to 0 instruction bytes. q = obj.Appendp(ctxt, q) q.As = AMOVD q.From.Type = obj.TYPE_MEM q.From.Reg = REGG q.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic q.To.Type = obj.TYPE_REG q.To.Reg = REG_R3 q = obj.Appendp(ctxt, q) q.As = ACMP q.From.Type = obj.TYPE_REG q.From.Reg = REG_R0 q.To.Type = obj.TYPE_REG q.To.Reg = REG_R3 q = obj.Appendp(ctxt, q) q.As = ABEQ q.To.Type = obj.TYPE_BRANCH p1 = q q = obj.Appendp(ctxt, q) q.As = AMOVD q.From.Type = obj.TYPE_MEM q.From.Reg = REG_R3 q.From.Offset = 0 // Panic.argp q.To.Type = obj.TYPE_REG q.To.Reg = REG_R4 q = obj.Appendp(ctxt, q) q.As = AADD q.From.Type = obj.TYPE_CONST q.From.Offset = int64(autosize) + ctxt.FixedFrameSize() q.Reg = REGSP q.To.Type = obj.TYPE_REG q.To.Reg = REG_R5 q = obj.Appendp(ctxt, q) q.As = ACMP q.From.Type = obj.TYPE_REG q.From.Reg = REG_R4 q.To.Type = obj.TYPE_REG q.To.Reg = REG_R5 q = obj.Appendp(ctxt, q) q.As = ABNE q.To.Type = obj.TYPE_BRANCH p2 = q q = obj.Appendp(ctxt, q) q.As = AADD q.From.Type = obj.TYPE_CONST q.From.Offset = ctxt.FixedFrameSize() q.Reg = REGSP q.To.Type = obj.TYPE_REG q.To.Reg = REG_R6 q = obj.Appendp(ctxt, q) q.As = AMOVD q.From.Type = obj.TYPE_REG q.From.Reg = REG_R6 q.To.Type = obj.TYPE_MEM q.To.Reg = REG_R3 q.To.Offset = 0 // Panic.argp q = obj.Appendp(ctxt, q) q.As = obj.ANOP p1.Pcond = q p2.Pcond = q } case obj.ARET: if p.From.Type == obj.TYPE_CONST { ctxt.Diag("using BECOME (%v) is not supported!", p) break } retTarget := p.To.Sym if cursym.Text.Mark&LEAF != 0 { if autosize == 0 { 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 = ctxt.NewProg() q.As = ABR q.Lineno = p.Lineno q.To.Type = obj.TYPE_REG q.To.Reg = REG_LR q.Mark |= BRANCH q.Spadj = +autosize q.Link = p.Link p.Link = q break } p.As = AMOVD p.From.Type = obj.TYPE_MEM p.From.Offset = 0 p.From.Reg = REGSP p.To.Type = obj.TYPE_REG p.To.Reg = REGTMP q = ctxt.NewProg() q.As = AMOVD q.Lineno = p.Lineno q.From.Type = obj.TYPE_REG q.From.Reg = REGTMP q.To.Type = obj.TYPE_REG q.To.Reg = REG_LR q.Link = p.Link p.Link = q p = q if false { // Debug bad returns q = ctxt.NewProg() q.As = AMOVD q.Lineno = p.Lineno q.From.Type = obj.TYPE_MEM q.From.Offset = 0 q.From.Reg = REGTMP q.To.Type = obj.TYPE_REG q.To.Reg = REGTMP q.Link = p.Link p.Link = q p = q } if autosize != 0 { q = ctxt.NewProg() q.As = AADD q.Lineno = p.Lineno 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.Link = p.Link p.Link = q } q1 = ctxt.NewProg() q1.As = ABR q1.Lineno = p.Lineno if retTarget == nil { q1.To.Type = obj.TYPE_REG q1.To.Reg = REG_LR } else { q1.To.Type = obj.TYPE_BRANCH q1.To.Sym = retTarget } q1.Mark |= BRANCH q1.Spadj = +autosize q1.Link = q.Link q.Link = q1 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) } } } }
func xfol(ctxt *obj.Link, p *obj.Prog, last **obj.Prog) { var q *obj.Prog var r *obj.Prog var b obj.As var i int loop: if p == nil { return } a := p.As if a == ABR { q = p.Pcond if (p.Mark&NOSCHED != 0) || q != nil && (q.Mark&NOSCHED != 0) { p.Mark |= FOLL (*last).Link = p *last = p p = p.Link xfol(ctxt, p, last) p = q if p != nil && p.Mark&FOLL == 0 { goto loop } return } if q != nil { p.Mark |= FOLL p = q if p.Mark&FOLL == 0 { goto loop } } } if p.Mark&FOLL != 0 { i = 0 q = p for ; i < 4; i, q = i+1, q.Link { if q == *last || (q.Mark&NOSCHED != 0) { break } b = 0 /* set */ a = q.As if a == obj.ANOP { i-- continue } if a == ABR || a == obj.ARET || a == ARFI || a == ARFCI || a == ARFID || a == AHRFID { goto copy } if q.Pcond == nil || (q.Pcond.Mark&FOLL != 0) { continue } b = relinv(a) if b == 0 { continue } copy: for { r = ctxt.NewProg() *r = *p if r.Mark&FOLL == 0 { fmt.Printf("can't happen 1\n") } r.Mark |= FOLL if p != q { p = p.Link (*last).Link = r *last = r continue } (*last).Link = r *last = r if a == ABR || a == obj.ARET || a == ARFI || a == ARFCI || a == ARFID || a == AHRFID { return } r.As = b r.Pcond = p.Link r.Link = p.Pcond if r.Link.Mark&FOLL == 0 { xfol(ctxt, r.Link, last) } if r.Pcond.Mark&FOLL == 0 { fmt.Printf("can't happen 2\n") } return } } a = ABR q = ctxt.NewProg() q.As = a q.Lineno = p.Lineno q.To.Type = obj.TYPE_BRANCH q.To.Offset = p.Pc q.Pcond = p p = q } p.Mark |= FOLL (*last).Link = p *last = p if a == ABR || a == obj.ARET || a == ARFI || a == ARFCI || a == ARFID || a == AHRFID { if p.Mark&NOSCHED != 0 { p = p.Link goto loop } return } if p.Pcond != nil { if a != ABL && p.Link != nil { xfol(ctxt, p.Link, last) p = p.Pcond if p == nil || (p.Mark&FOLL != 0) { return } goto loop } } p = p.Link goto loop }
func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) { o1 := uint32(0) o2 := uint32(0) o3 := uint32(0) o4 := uint32(0) switch o.type_ { default: ctxt.Diag("unknown type %d %v", o.type_) prasm(p) case 0: /* pseudo ops */ break case 1: /* mov r1,r2 ==> OR r1,r0,r2 */ a := AOR if p.As == AMOVW { a = AADDU // sign-extended to high 32 bits } o1 = OP_RRR(oprrr(ctxt, a), uint32(p.From.Reg), uint32(REGZERO), uint32(p.To.Reg)) case 2: /* add/sub r1,[r2],r3 */ r := int(p.Reg) if r == 0 { r = int(p.To.Reg) } o1 = OP_RRR(oprrr(ctxt, p.As), uint32(p.From.Reg), uint32(r), uint32(p.To.Reg)) case 3: /* mov $soreg, r ==> or/add $i,o,r */ v := regoff(ctxt, &p.From) r := int(p.From.Reg) if r == 0 { r = int(o.param) } a := AADDVU if o.a1 == C_ANDCON { a = AOR } o1 = OP_IRR(opirr(ctxt, a), uint32(v), uint32(r), uint32(p.To.Reg)) case 4: /* add $scon,[r1],r2 */ v := regoff(ctxt, &p.From) r := int(p.Reg) if r == 0 { r = int(p.To.Reg) } o1 = OP_IRR(opirr(ctxt, p.As), uint32(v), uint32(r), uint32(p.To.Reg)) case 5: /* syscall */ o1 = oprrr(ctxt, p.As) case 6: /* beq r1,[r2],sbra */ v := int32(0) if p.Pcond == nil { v = int32(-4) >> 2 } else { v = int32(p.Pcond.Pc-p.Pc-4) >> 2 } if (v<<16)>>16 != v { ctxt.Diag("short branch too far\n%v", p) } o1 = OP_IRR(opirr(ctxt, p.As), uint32(v), uint32(p.From.Reg), uint32(p.Reg)) // for ABFPT and ABFPF only: always fill delay slot with 0 // see comments in func preprocess for details. o2 = 0 case 7: /* mov r, soreg ==> sw o(r) */ r := int(p.To.Reg) if r == 0 { r = int(o.param) } v := regoff(ctxt, &p.To) o1 = OP_IRR(opirr(ctxt, p.As), uint32(v), uint32(r), uint32(p.From.Reg)) case 8: /* mov soreg, r ==> lw o(r) */ r := int(p.From.Reg) if r == 0 { r = int(o.param) } v := regoff(ctxt, &p.From) o1 = OP_IRR(opirr(ctxt, -p.As), uint32(v), uint32(r), uint32(p.To.Reg)) case 9: /* sll r1,[r2],r3 */ r := int(p.Reg) if r == 0 { r = int(p.To.Reg) } o1 = OP_RRR(oprrr(ctxt, p.As), uint32(r), uint32(p.From.Reg), uint32(p.To.Reg)) case 10: /* add $con,[r1],r2 ==> mov $con, t; add t,[r1],r2 */ v := regoff(ctxt, &p.From) a := AOR if v < 0 { a = AADDU } o1 = OP_IRR(opirr(ctxt, a), uint32(v), uint32(0), uint32(REGTMP)) r := int(p.Reg) if r == 0 { r = int(p.To.Reg) } o2 = OP_RRR(oprrr(ctxt, p.As), uint32(REGTMP), uint32(r), uint32(p.To.Reg)) case 11: /* jmp lbra */ v := int32(0) if aclass(ctxt, &p.To) == C_SBRA && p.To.Sym == nil && p.As == AJMP { // use PC-relative branch for short branches // BEQ R0, R0, sbra if p.Pcond == nil { v = int32(-4) >> 2 } else { v = int32(p.Pcond.Pc-p.Pc-4) >> 2 } if (v<<16)>>16 == v { o1 = OP_IRR(opirr(ctxt, ABEQ), uint32(v), uint32(REGZERO), uint32(REGZERO)) break } } if p.Pcond == nil { v = int32(p.Pc) >> 2 } else { v = int32(p.Pcond.Pc) >> 2 } o1 = OP_JMP(opirr(ctxt, p.As), uint32(v)) if p.To.Sym == nil { p.To.Sym = ctxt.Cursym.Text.From.Sym p.To.Offset = p.Pcond.Pc } rel := obj.Addrel(ctxt.Cursym) rel.Off = int32(ctxt.Pc) rel.Siz = 4 rel.Sym = p.To.Sym rel.Add = p.To.Offset if p.As == AJAL { rel.Type = obj.R_CALLMIPS } else { rel.Type = obj.R_JMPMIPS } case 12: /* movbs r,r */ v := 16 if p.As == AMOVB { v = 24 } o1 = OP_SRR(opirr(ctxt, ASLL), uint32(v), uint32(p.From.Reg), uint32(p.To.Reg)) o2 = OP_SRR(opirr(ctxt, ASRA), uint32(v), uint32(p.To.Reg), uint32(p.To.Reg)) case 13: /* movbu r,r */ if p.As == AMOVBU { o1 = OP_IRR(opirr(ctxt, AAND), uint32(0xff), uint32(p.From.Reg), uint32(p.To.Reg)) } else { o1 = OP_IRR(opirr(ctxt, AAND), uint32(0xffff), uint32(p.From.Reg), uint32(p.To.Reg)) } case 14: /* movwu r,r */ o1 = OP_SRR(opirr(ctxt, -ASLLV), uint32(0), uint32(p.From.Reg), uint32(p.To.Reg)) o2 = OP_SRR(opirr(ctxt, -ASRLV), uint32(0), uint32(p.To.Reg), uint32(p.To.Reg)) case 16: /* sll $c,[r1],r2 */ v := regoff(ctxt, &p.From) r := int(p.Reg) if r == 0 { r = int(p.To.Reg) } /* OP_SRR will use only the low 5 bits of the shift value */ if v >= 32 && vshift(p.As) { o1 = OP_SRR(opirr(ctxt, -p.As), uint32(v-32), uint32(r), uint32(p.To.Reg)) } else { o1 = OP_SRR(opirr(ctxt, p.As), uint32(v), uint32(r), uint32(p.To.Reg)) } case 18: /* jmp [r1],0(r2) */ r := int(p.Reg) if r == 0 { r = int(o.param) } o1 = OP_RRR(oprrr(ctxt, p.As), uint32(0), uint32(p.To.Reg), uint32(r)) rel := obj.Addrel(ctxt.Cursym) rel.Off = int32(ctxt.Pc) rel.Siz = 0 rel.Type = obj.R_CALLIND case 19: /* mov $lcon,r ==> lu+or */ v := regoff(ctxt, &p.From) o1 = OP_IRR(opirr(ctxt, ALUI), uint32(v>>16), uint32(REGZERO), uint32(p.To.Reg)) o2 = OP_IRR(opirr(ctxt, AOR), uint32(v), uint32(p.To.Reg), uint32(p.To.Reg)) case 20: /* mov lo/hi,r */ a := OP(2, 0) /* mfhi */ if p.From.Reg == REG_LO { a = OP(2, 2) /* mflo */ } o1 = OP_RRR(a, uint32(REGZERO), uint32(REGZERO), uint32(p.To.Reg)) case 21: /* mov r,lo/hi */ a := OP(2, 1) /* mthi */ if p.To.Reg == REG_LO { a = OP(2, 3) /* mtlo */ } o1 = OP_RRR(a, uint32(REGZERO), uint32(p.From.Reg), uint32(REGZERO)) case 22: /* mul r1,r2 */ o1 = OP_RRR(oprrr(ctxt, p.As), uint32(p.From.Reg), uint32(p.Reg), uint32(REGZERO)) case 23: /* add $lcon,r1,r2 ==> lu+or+add */ v := regoff(ctxt, &p.From) o1 = OP_IRR(opirr(ctxt, ALUI), uint32(v>>16), uint32(REGZERO), uint32(REGTMP)) o2 = OP_IRR(opirr(ctxt, AOR), uint32(v), uint32(REGTMP), uint32(REGTMP)) r := int(p.Reg) if r == 0 { r = int(p.To.Reg) } o3 = OP_RRR(oprrr(ctxt, p.As), uint32(REGTMP), uint32(r), uint32(p.To.Reg)) case 24: /* mov $ucon,r ==> lu r */ v := regoff(ctxt, &p.From) o1 = OP_IRR(opirr(ctxt, ALUI), uint32(v>>16), uint32(REGZERO), uint32(p.To.Reg)) case 25: /* add/and $ucon,[r1],r2 ==> lu $con,t; add t,[r1],r2 */ v := regoff(ctxt, &p.From) o1 = OP_IRR(opirr(ctxt, ALUI), uint32(v>>16), uint32(REGZERO), uint32(REGTMP)) r := int(p.Reg) if r == 0 { r = int(p.To.Reg) } o2 = OP_RRR(oprrr(ctxt, p.As), uint32(REGTMP), uint32(r), uint32(p.To.Reg)) case 26: /* mov $lsext/auto/oreg,r ==> lu+or+add */ v := regoff(ctxt, &p.From) o1 = OP_IRR(opirr(ctxt, ALUI), uint32(v>>16), uint32(REGZERO), uint32(REGTMP)) o2 = OP_IRR(opirr(ctxt, AOR), uint32(v), uint32(REGTMP), uint32(REGTMP)) r := int(p.From.Reg) if r == 0 { r = int(o.param) } o3 = OP_RRR(oprrr(ctxt, AADDVU), uint32(REGTMP), uint32(r), uint32(p.To.Reg)) case 27: /* mov [sl]ext/auto/oreg,fr ==> lwc1 o(r) */ v := regoff(ctxt, &p.From) r := int(p.From.Reg) if r == 0 { r = int(o.param) } a := -AMOVF if p.As == AMOVD { a = -AMOVD } switch o.size { case 12: o1 = OP_IRR(opirr(ctxt, ALUI), uint32((v+1<<15)>>16), uint32(REGZERO), uint32(REGTMP)) o2 = OP_RRR(oprrr(ctxt, AADDVU), uint32(r), uint32(REGTMP), uint32(REGTMP)) o3 = OP_IRR(opirr(ctxt, a), uint32(v), uint32(REGTMP), uint32(p.To.Reg)) case 4: o1 = OP_IRR(opirr(ctxt, a), uint32(v), uint32(r), uint32(p.To.Reg)) } case 28: /* mov fr,[sl]ext/auto/oreg ==> swc1 o(r) */ v := regoff(ctxt, &p.To) r := int(p.To.Reg) if r == 0 { r = int(o.param) } a := AMOVF if p.As == AMOVD { a = AMOVD } switch o.size { case 12: o1 = OP_IRR(opirr(ctxt, ALUI), uint32((v+1<<15)>>16), uint32(REGZERO), uint32(REGTMP)) o2 = OP_RRR(oprrr(ctxt, AADDVU), uint32(r), uint32(REGTMP), uint32(REGTMP)) o3 = OP_IRR(opirr(ctxt, a), uint32(v), uint32(REGTMP), uint32(p.From.Reg)) case 4: o1 = OP_IRR(opirr(ctxt, a), uint32(v), uint32(r), uint32(p.From.Reg)) } case 30: /* movw r,fr */ a := SP(2, 1) | (4 << 21) /* mtc1 */ o1 = OP_RRR(a, uint32(p.From.Reg), uint32(0), uint32(p.To.Reg)) case 31: /* movw fr,r */ a := SP(2, 1) | (0 << 21) /* mtc1 */ o1 = OP_RRR(a, uint32(p.To.Reg), uint32(0), uint32(p.From.Reg)) case 32: /* fadd fr1,[fr2],fr3 */ r := int(p.Reg) if r == 0 { r = int(p.To.Reg) } o1 = OP_FRRR(oprrr(ctxt, p.As), uint32(p.From.Reg), uint32(r), uint32(p.To.Reg)) case 33: /* fabs fr1, fr3 */ o1 = OP_FRRR(oprrr(ctxt, p.As), uint32(0), uint32(p.From.Reg), uint32(p.To.Reg)) case 34: /* mov $con,fr ==> or/add $i,t; mov t,fr */ v := regoff(ctxt, &p.From) a := AADDU if o.a1 == C_ANDCON { a = AOR } o1 = OP_IRR(opirr(ctxt, a), uint32(v), uint32(0), uint32(REGTMP)) o2 = OP_RRR(SP(2, 1)|(4<<21), uint32(REGTMP), uint32(0), uint32(p.To.Reg)) /* mtc1 */ case 35: /* mov r,lext/auto/oreg ==> sw o(REGTMP) */ v := regoff(ctxt, &p.To) r := int(p.To.Reg) if r == 0 { r = int(o.param) } o1 = OP_IRR(opirr(ctxt, ALUI), uint32((v+1<<15)>>16), uint32(REGZERO), uint32(REGTMP)) o2 = OP_RRR(oprrr(ctxt, AADDVU), uint32(r), uint32(REGTMP), uint32(REGTMP)) o3 = OP_IRR(opirr(ctxt, p.As), uint32(v), uint32(REGTMP), uint32(p.From.Reg)) case 36: /* mov lext/auto/oreg,r ==> lw o(REGTMP) */ v := regoff(ctxt, &p.From) r := int(p.From.Reg) if r == 0 { r = int(o.param) } o1 = OP_IRR(opirr(ctxt, ALUI), uint32((v+1<<15)>>16), uint32(REGZERO), uint32(REGTMP)) o2 = OP_RRR(oprrr(ctxt, AADDVU), uint32(r), uint32(REGTMP), uint32(REGTMP)) o3 = OP_IRR(opirr(ctxt, -p.As), uint32(v), uint32(REGTMP), uint32(p.To.Reg)) case 37: /* movw r,mr */ a := SP(2, 0) | (4 << 21) /* mtc0 */ if p.As == AMOVV { a = SP(2, 0) | (5 << 21) /* dmtc0 */ } o1 = OP_RRR(a, uint32(p.From.Reg), uint32(0), uint32(p.To.Reg)) case 38: /* movw mr,r */ a := SP(2, 0) | (0 << 21) /* mfc0 */ if p.As == AMOVV { a = SP(2, 0) | (1 << 21) /* dmfc0 */ } o1 = OP_RRR(a, uint32(p.To.Reg), uint32(0), uint32(p.From.Reg)) case 40: /* word */ o1 = uint32(regoff(ctxt, &p.From)) case 41: /* movw f,fcr */ o1 = OP_RRR(SP(2, 1)|(2<<21), uint32(REGZERO), uint32(0), uint32(p.To.Reg)) /* mfcc1 */ o2 = OP_RRR(SP(2, 1)|(6<<21), uint32(p.From.Reg), uint32(0), uint32(p.To.Reg)) /* mtcc1 */ case 42: /* movw fcr,r */ o1 = OP_RRR(SP(2, 1)|(2<<21), uint32(p.To.Reg), uint32(0), uint32(p.From.Reg)) /* mfcc1 */ case 47: /* movv r,fr */ a := SP(2, 1) | (5 << 21) /* dmtc1 */ o1 = OP_RRR(a, uint32(p.From.Reg), uint32(0), uint32(p.To.Reg)) case 48: /* movv fr,r */ a := SP(2, 1) | (1 << 21) /* dmtc1 */ o1 = OP_RRR(a, uint32(p.To.Reg), uint32(0), uint32(p.From.Reg)) case 49: /* undef */ o1 = 52 /* trap -- teq r0, r0 */ /* relocation operations */ case 50: /* mov r,addr ==> lu + add REGSB, REGTMP + sw o(REGTMP) */ o1 = OP_IRR(opirr(ctxt, ALUI), uint32(0), uint32(REGZERO), uint32(REGTMP)) rel := obj.Addrel(ctxt.Cursym) rel.Off = int32(ctxt.Pc) rel.Siz = 4 rel.Sym = p.To.Sym rel.Add = p.To.Offset rel.Type = obj.R_ADDRMIPSU o2 = OP_RRR(oprrr(ctxt, AADDVU), uint32(REGSB), uint32(REGTMP), uint32(REGTMP)) o3 = OP_IRR(opirr(ctxt, p.As), uint32(0), uint32(REGTMP), uint32(p.From.Reg)) rel2 := obj.Addrel(ctxt.Cursym) rel2.Off = int32(ctxt.Pc + 8) rel2.Siz = 4 rel2.Sym = p.To.Sym rel2.Add = p.To.Offset rel2.Type = obj.R_ADDRMIPS case 51: /* mov addr,r ==> lu + add REGSB, REGTMP + lw o(REGTMP) */ o1 = OP_IRR(opirr(ctxt, ALUI), uint32(0), uint32(REGZERO), uint32(REGTMP)) rel := obj.Addrel(ctxt.Cursym) rel.Off = int32(ctxt.Pc) rel.Siz = 4 rel.Sym = p.From.Sym rel.Add = p.From.Offset rel.Type = obj.R_ADDRMIPSU o2 = OP_RRR(oprrr(ctxt, AADDVU), uint32(REGSB), uint32(REGTMP), uint32(REGTMP)) o3 = OP_IRR(opirr(ctxt, -p.As), uint32(0), uint32(REGTMP), uint32(p.To.Reg)) rel2 := obj.Addrel(ctxt.Cursym) rel2.Off = int32(ctxt.Pc + 8) rel2.Siz = 4 rel2.Sym = p.From.Sym rel2.Add = p.From.Offset rel2.Type = obj.R_ADDRMIPS case 52: /* mov $lext, r ==> lu + add REGSB, r + add */ o1 = OP_IRR(opirr(ctxt, ALUI), uint32(0), uint32(REGZERO), uint32(p.To.Reg)) rel := obj.Addrel(ctxt.Cursym) rel.Off = int32(ctxt.Pc) rel.Siz = 4 rel.Sym = p.From.Sym rel.Add = p.From.Offset rel.Type = obj.R_ADDRMIPSU o2 = OP_RRR(oprrr(ctxt, AADDVU), uint32(REGSB), uint32(p.To.Reg), uint32(p.To.Reg)) o3 = OP_IRR(opirr(ctxt, AADDVU), uint32(0), uint32(p.To.Reg), uint32(p.To.Reg)) rel2 := obj.Addrel(ctxt.Cursym) rel2.Off = int32(ctxt.Pc + 8) rel2.Siz = 4 rel2.Sym = p.From.Sym rel2.Add = p.From.Offset rel2.Type = obj.R_ADDRMIPS case 53: /* mov r, tlsvar ==> rdhwr + sw o(r3) */ // clobbers R3 ! // load thread pointer with RDHWR, R3 is used for fast kernel emulation on Linux o1 = (037<<26 + 073) | (29 << 11) | (3 << 16) // rdhwr $29, r3 o2 = OP_IRR(opirr(ctxt, p.As), uint32(0), uint32(REG_R3), uint32(p.From.Reg)) rel := obj.Addrel(ctxt.Cursym) rel.Off = int32(ctxt.Pc + 4) rel.Siz = 4 rel.Sym = p.To.Sym rel.Add = p.To.Offset rel.Type = obj.R_ADDRMIPSTLS case 54: /* mov tlsvar, r ==> rdhwr + lw o(r3) */ // clobbers R3 ! o1 = (037<<26 + 073) | (29 << 11) | (3 << 16) // rdhwr $29, r3 o2 = OP_IRR(opirr(ctxt, -p.As), uint32(0), uint32(REG_R3), uint32(p.To.Reg)) rel := obj.Addrel(ctxt.Cursym) rel.Off = int32(ctxt.Pc + 4) rel.Siz = 4 rel.Sym = p.From.Sym rel.Add = p.From.Offset rel.Type = obj.R_ADDRMIPSTLS case 55: /* mov $tlsvar, r ==> rdhwr + add */ // clobbers R3 ! o1 = (037<<26 + 073) | (29 << 11) | (3 << 16) // rdhwr $29, r3 o2 = OP_IRR(opirr(ctxt, AADDVU), uint32(0), uint32(REG_R3), uint32(p.To.Reg)) rel := obj.Addrel(ctxt.Cursym) rel.Off = int32(ctxt.Pc + 4) rel.Siz = 4 rel.Sym = p.From.Sym rel.Add = p.From.Offset rel.Type = obj.R_ADDRMIPSTLS } out[0] = o1 out[1] = o2 out[2] = o3 out[3] = o4 return }
func buildop(ctxt *obj.Link) { var n int for i := 0; i < C_NCLASS; i++ { for n = 0; n < C_NCLASS; n++ { if cmp(n, i) { xcmp[i][n] = true } } } for n = 0; optab[n].as != obj.AXXX; n++ { } sort.Sort(ocmp(optab[:n])) for i := 0; i < n; i++ { r := optab[i].as r0 := r & obj.AMask start := i for optab[i].as == r { i++ } oprange[r0] = optab[start:i] i-- switch r { default: ctxt.Diag("unknown op in build: %v", obj.Aconv(r)) log.Fatalf("bad code") case AABSF: opset(AMOVFD, r0) opset(AMOVDF, r0) opset(AMOVWF, r0) opset(AMOVFW, r0) opset(AMOVWD, r0) opset(AMOVDW, r0) opset(ANEGF, r0) opset(ANEGD, r0) opset(AABSD, r0) opset(ATRUNCDW, r0) opset(ATRUNCFW, r0) opset(ATRUNCDV, r0) opset(ATRUNCFV, r0) opset(AMOVVF, r0) opset(AMOVFV, r0) opset(AMOVVD, r0) opset(AMOVDV, r0) case AADD: opset(ASGT, r0) opset(ASGTU, r0) opset(AADDU, r0) opset(AADDV, r0) opset(AADDVU, r0) case AADDF: opset(ADIVF, r0) opset(ADIVD, r0) opset(AMULF, r0) opset(AMULD, r0) opset(ASUBF, r0) opset(ASUBD, r0) opset(AADDD, r0) case AAND: opset(AOR, r0) opset(AXOR, r0) case ABEQ: opset(ABNE, r0) case ABLEZ: opset(ABGEZ, r0) opset(ABGEZAL, r0) opset(ABLTZ, r0) opset(ABLTZAL, r0) opset(ABGTZ, r0) case AMOVB: opset(AMOVH, r0) case AMOVBU: opset(AMOVHU, r0) case AMUL: opset(AREM, r0) opset(AREMU, r0) opset(ADIVU, r0) opset(AMULU, r0) opset(ADIV, r0) opset(ADIVV, r0) opset(ADIVVU, r0) opset(AMULV, r0) opset(AMULVU, r0) opset(AREMV, r0) opset(AREMVU, r0) case ASLL: opset(ASRL, r0) opset(ASRA, r0) opset(ASLLV, r0) opset(ASRAV, r0) opset(ASRLV, r0) case ASUB: opset(ASUBU, r0) opset(ASUBV, r0) opset(ASUBVU, r0) opset(ANOR, r0) case ASYSCALL: opset(ATLBP, r0) opset(ATLBR, r0) opset(ATLBWI, r0) opset(ATLBWR, r0) case ACMPEQF: opset(ACMPGTF, r0) opset(ACMPGTD, r0) opset(ACMPGEF, r0) opset(ACMPGED, r0) opset(ACMPEQD, r0) case ABFPT: opset(ABFPF, r0) case AMOVWL: opset(AMOVWR, r0) opset(AMOVVR, r0) opset(AMOVVL, r0) case AMOVW, AMOVD, AMOVF, AMOVV, ABREAK, ARFE, AJAL, AJMP, AMOVWU, AWORD, obj.ANOP, obj.ATEXT, obj.AUNDEF, obj.AUSEFIELD, obj.AFUNCDATA, obj.APCDATA, obj.ADUFFZERO, obj.ADUFFCOPY: break } } }
func aclass(ctxt *obj.Link, a *obj.Addr) int { switch a.Type { case obj.TYPE_NONE: return C_NONE case obj.TYPE_REG: if REG_R0 <= a.Reg && a.Reg <= REG_R31 { return C_REG } if REG_F0 <= a.Reg && a.Reg <= REG_F31 { return C_FREG } if REG_M0 <= a.Reg && a.Reg <= REG_M31 { return C_MREG } if REG_FCR0 <= a.Reg && a.Reg <= REG_FCR31 { return C_FCREG } if a.Reg == REG_LO { return C_LO } if a.Reg == REG_HI { return C_HI } return C_GOK case obj.TYPE_MEM: switch a.Name { case obj.NAME_EXTERN, obj.NAME_STATIC: if a.Sym == nil { break } ctxt.Instoffset = a.Offset if a.Sym != nil { // use relocation if a.Sym.Type == obj.STLSBSS { return C_TLS } return C_ADDR } return C_LEXT case obj.NAME_AUTO: ctxt.Instoffset = int64(ctxt.Autosize) + a.Offset if ctxt.Instoffset >= -BIG && ctxt.Instoffset < BIG { return C_SAUTO } return C_LAUTO case obj.NAME_PARAM: ctxt.Instoffset = int64(ctxt.Autosize) + a.Offset + 8 if ctxt.Instoffset >= -BIG && ctxt.Instoffset < BIG { return C_SAUTO } return C_LAUTO case obj.NAME_NONE: ctxt.Instoffset = a.Offset if ctxt.Instoffset == 0 { return C_ZOREG } if ctxt.Instoffset >= -BIG && ctxt.Instoffset < BIG { return C_SOREG } return C_LOREG } return C_GOK case obj.TYPE_TEXTSIZE: return C_TEXTSIZE case obj.TYPE_CONST, obj.TYPE_ADDR: switch a.Name { case obj.NAME_NONE: ctxt.Instoffset = a.Offset if a.Reg != 0 { if -BIG <= ctxt.Instoffset && ctxt.Instoffset <= BIG { return C_SACON } if isint32(ctxt.Instoffset) { return C_LACON } return C_DACON } goto consize case obj.NAME_EXTERN, obj.NAME_STATIC: s := a.Sym if s == nil { break } if s.Type == obj.SCONST { ctxt.Instoffset = a.Offset goto consize } ctxt.Instoffset = a.Offset if s.Type == obj.STLSBSS { return C_STCON // address of TLS variable } return C_LECON case obj.NAME_AUTO: ctxt.Instoffset = int64(ctxt.Autosize) + a.Offset if ctxt.Instoffset >= -BIG && ctxt.Instoffset < BIG { return C_SACON } return C_LACON case obj.NAME_PARAM: ctxt.Instoffset = int64(ctxt.Autosize) + a.Offset + 8 if ctxt.Instoffset >= -BIG && ctxt.Instoffset < BIG { return C_SACON } return C_LACON } return C_GOK consize: if ctxt.Instoffset >= 0 { if ctxt.Instoffset == 0 { return C_ZCON } if ctxt.Instoffset <= 0x7fff { return C_SCON } if ctxt.Instoffset <= 0xffff { return C_ANDCON } if ctxt.Instoffset&0xffff == 0 && isuint32(uint64(ctxt.Instoffset)) { /* && (instoffset & (1<<31)) == 0) */ return C_UCON } if isint32(ctxt.Instoffset) || isuint32(uint64(ctxt.Instoffset)) { return C_LCON } return C_LCON // C_DCON } if ctxt.Instoffset >= -0x8000 { return C_ADDCON } if ctxt.Instoffset&0xffff == 0 && isint32(ctxt.Instoffset) { return C_UCON } if isint32(ctxt.Instoffset) { return C_LCON } return C_LCON // C_DCON case obj.TYPE_BRANCH: return C_SBRA } return C_GOK }
func preprocess(ctxt *obj.Link, cursym *obj.LSym) { autosize := int32(0) ctxt.Cursym = cursym if cursym.Text == nil || cursym.Text.Link == nil { return } softfloat(ctxt, cursym) p := cursym.Text autoffset := int32(p.To.Offset) if autoffset < 0 { autoffset = 0 } cursym.Locals = autoffset cursym.Args = p.To.Val.(int32) /* * find leaf subroutines * strip NOPs * expand RET * expand BECOME pseudo */ var q1 *obj.Prog var q *obj.Prog for p := cursym.Text; p != nil; p = p.Link { switch p.As { case obj.ATEXT: p.Mark |= LEAF case obj.ARET: break case ADIV, ADIVU, AMOD, AMODU: q = p if ctxt.Sym_div == nil { initdiv(ctxt) } cursym.Text.Mark &^= LEAF continue case obj.ANOP: q1 = p.Link q.Link = q1 /* q is non-nop */ if q1 != nil { q1.Mark |= p.Mark } continue case ABL, ABX, obj.ADUFFZERO, obj.ADUFFCOPY: cursym.Text.Mark &^= LEAF fallthrough case AB, ABEQ, ABNE, ABCS, ABHS, ABCC, ABLO, ABMI, ABPL, ABVS, ABVC, ABHI, ABLS, ABGE, ABLT, ABGT, ABLE: q1 = p.Pcond if q1 != nil { for q1.As == obj.ANOP { q1 = q1.Link p.Pcond = q1 } } } q = p } var p1 *obj.Prog var p2 *obj.Prog var q2 *obj.Prog for p := cursym.Text; p != nil; p = p.Link { o := p.As switch o { case obj.ATEXT: autosize = int32(p.To.Offset + 4) if autosize <= 4 { if cursym.Text.Mark&LEAF != 0 { p.To.Offset = -4 autosize = 0 } } if autosize == 0 && cursym.Text.Mark&LEAF == 0 { if ctxt.Debugvlog != 0 { fmt.Fprintf(ctxt.Bso, "save suppressed in: %s\n", cursym.Name) ctxt.Bso.Flush() } cursym.Text.Mark |= LEAF } if cursym.Text.Mark&LEAF != 0 { cursym.Leaf = true if autosize == 0 { break } } if p.From3.Offset&obj.NOSPLIT == 0 { p = stacksplit(ctxt, p, autosize) // emit split check } // MOVW.W R14,$-autosize(SP) p = obj.Appendp(ctxt, p) p.As = AMOVW p.Scond |= C_WBIT p.From.Type = obj.TYPE_REG p.From.Reg = REGLINK p.To.Type = obj.TYPE_MEM p.To.Offset = int64(-autosize) p.To.Reg = REGSP p.Spadj = autosize if cursym.Text.From3.Offset&obj.WRAPPER != 0 { // if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame // // MOVW g_panic(g), R1 // CMP $0, R1 // B.EQ end // MOVW panic_argp(R1), R2 // ADD $(autosize+4), R13, R3 // CMP R2, R3 // B.NE end // ADD $4, R13, R4 // MOVW R4, panic_argp(R1) // end: // NOP // // The NOP is needed to give the jumps somewhere to land. // It is a liblink NOP, not an ARM NOP: it encodes to 0 instruction bytes. p = obj.Appendp(ctxt, p) p.As = AMOVW p.From.Type = obj.TYPE_MEM p.From.Reg = REGG p.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic p.To.Type = obj.TYPE_REG p.To.Reg = REG_R1 p = obj.Appendp(ctxt, p) p.As = ACMP p.From.Type = obj.TYPE_CONST p.From.Offset = 0 p.Reg = REG_R1 p = obj.Appendp(ctxt, p) p.As = ABEQ p.To.Type = obj.TYPE_BRANCH p1 = p p = obj.Appendp(ctxt, p) p.As = AMOVW p.From.Type = obj.TYPE_MEM p.From.Reg = REG_R1 p.From.Offset = 0 // Panic.argp p.To.Type = obj.TYPE_REG p.To.Reg = REG_R2 p = obj.Appendp(ctxt, p) p.As = AADD p.From.Type = obj.TYPE_CONST p.From.Offset = int64(autosize) + 4 p.Reg = REG_R13 p.To.Type = obj.TYPE_REG p.To.Reg = REG_R3 p = obj.Appendp(ctxt, p) p.As = ACMP p.From.Type = obj.TYPE_REG p.From.Reg = REG_R2 p.Reg = REG_R3 p = obj.Appendp(ctxt, p) p.As = ABNE p.To.Type = obj.TYPE_BRANCH p2 = p p = obj.Appendp(ctxt, p) p.As = AADD p.From.Type = obj.TYPE_CONST p.From.Offset = 4 p.Reg = REG_R13 p.To.Type = obj.TYPE_REG p.To.Reg = REG_R4 p = obj.Appendp(ctxt, p) p.As = AMOVW p.From.Type = obj.TYPE_REG p.From.Reg = REG_R4 p.To.Type = obj.TYPE_MEM p.To.Reg = REG_R1 p.To.Offset = 0 // Panic.argp p = obj.Appendp(ctxt, p) p.As = obj.ANOP p1.Pcond = p p2.Pcond = p } case obj.ARET: nocache(p) if cursym.Text.Mark&LEAF != 0 { if autosize == 0 { p.As = AB p.From = obj.Addr{} if p.To.Sym != nil { // retjmp p.To.Type = obj.TYPE_BRANCH } else { p.To.Type = obj.TYPE_MEM p.To.Offset = 0 p.To.Reg = REGLINK } break } } p.As = AMOVW 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(ctxt, p) 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.Text.From3.Offset&obj.NOSPLIT != 0 { ctxt.Diag("cannot divide in NOSPLIT function") } if ctxt.Debugdivmod != 0 { 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.Lineno = q1.Lineno 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(ctxt, p) p.As = AMOVW p.Lineno = q1.Lineno 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,REGTMP */ p = obj.Appendp(ctxt, p) p.As = AMOVW p.Lineno = q1.Lineno 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 = REGTMP p.To.Offset = 0 /* CALL appropriate */ p = obj.Appendp(ctxt, p) p.As = ABL p.Lineno = q1.Lineno p.To.Type = obj.TYPE_BRANCH switch o { case ADIV: p.To.Sym = ctxt.Sym_div case ADIVU: p.To.Sym = ctxt.Sym_divu case AMOD: p.To.Sym = ctxt.Sym_mod case AMODU: p.To.Sym = ctxt.Sym_modu } /* MOV REGTMP, b */ p = obj.Appendp(ctxt, p) p.As = AMOVW p.Lineno = q1.Lineno 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) } } } }
func oprrr(ctxt *obj.Link, a obj.As) uint32 { switch a { case AADD: return OP(4, 0) case AADDU: return OP(4, 1) case ASGT: return OP(5, 2) case ASGTU: return OP(5, 3) case AAND: return OP(4, 4) case AOR: return OP(4, 5) case AXOR: return OP(4, 6) case ASUB: return OP(4, 2) case ASUBU: return OP(4, 3) case ANOR: return OP(4, 7) case ASLL: return OP(0, 4) case ASRL: return OP(0, 6) case ASRA: return OP(0, 7) case ASLLV: return OP(2, 4) case ASRLV: return OP(2, 6) case ASRAV: return OP(2, 7) case AADDV: return OP(5, 4) case AADDVU: return OP(5, 5) case ASUBV: return OP(5, 6) case ASUBVU: return OP(5, 7) case AREM, ADIV: return OP(3, 2) case AREMU, ADIVU: return OP(3, 3) case AMUL: return OP(3, 0) case AMULU: return OP(3, 1) case AREMV, ADIVV: return OP(3, 6) case AREMVU, ADIVVU: return OP(3, 7) case AMULV: return OP(3, 4) case AMULVU: return OP(3, 5) case AJMP: return OP(1, 0) case AJAL: return OP(1, 1) case ABREAK: return OP(1, 5) case ASYSCALL: return OP(1, 4) case ATLBP: return MMU(1, 0) case ATLBR: return MMU(0, 1) case ATLBWI: return MMU(0, 2) case ATLBWR: return MMU(0, 6) case ARFE: return MMU(2, 0) case ADIVF: return FPF(0, 3) case ADIVD: return FPD(0, 3) case AMULF: return FPF(0, 2) case AMULD: return FPD(0, 2) case ASUBF: return FPF(0, 1) case ASUBD: return FPD(0, 1) case AADDF: return FPF(0, 0) case AADDD: return FPD(0, 0) case ATRUNCFV: return FPF(1, 1) case ATRUNCDV: return FPD(1, 1) case ATRUNCFW: return FPF(1, 5) case ATRUNCDW: return FPD(1, 5) case AMOVFV: return FPF(4, 5) case AMOVDV: return FPD(4, 5) case AMOVVF: return FPV(4, 0) case AMOVVD: return FPV(4, 1) case AMOVFW: return FPF(4, 4) case AMOVDW: return FPD(4, 4) case AMOVWF: return FPW(4, 0) case AMOVDF: return FPD(4, 0) case AMOVWD: return FPW(4, 1) case AMOVFD: return FPF(4, 1) case AABSF: return FPF(0, 5) case AABSD: return FPD(0, 5) case AMOVF: return FPF(0, 6) case AMOVD: return FPD(0, 6) case ANEGF: return FPF(0, 7) case ANEGD: return FPD(0, 7) case ACMPEQF: return FPF(6, 2) case ACMPEQD: return FPD(6, 2) case ACMPGTF: return FPF(7, 4) case ACMPGTD: return FPD(7, 4) case ACMPGEF: return FPF(7, 6) case ACMPGED: return FPD(7, 6) } if a < 0 { ctxt.Diag("bad rrr opcode -%v", obj.Aconv(-a)) } else { ctxt.Diag("bad rrr opcode %v", obj.Aconv(a)) } return 0 }
func progedit(ctxt *obj.Link, p *obj.Prog) { p.From.Class = 0 p.To.Class = 0 // Rewrite B/BL to symbol as TYPE_BRANCH. switch p.As { case AB, ABL, obj.ADUFFZERO, obj.ADUFFCOPY: if p.To.Type == obj.TYPE_MEM && (p.To.Name == obj.NAME_EXTERN || p.To.Name == obj.NAME_STATIC) && p.To.Sym != nil { p.To.Type = obj.TYPE_BRANCH } } // Replace TLS register fetches on older ARM processors. switch p.As { // Treat MRC 15, 0, <reg>, C13, C0, 3 specially. case AMRC: if p.To.Offset&0xffff0fff == 0xee1d0f70 { // Because the instruction might be rewritten to a BL which returns in R0 // the register must be zero. if p.To.Offset&0xf000 != 0 { ctxt.Diag("%v: TLS MRC instruction must write to R0 as it might get translated into a BL instruction", p.Line()) } if ctxt.Goarm < 7 { // Replace it with BL runtime.read_tls_fallback(SB) for ARM CPUs that lack the tls extension. if progedit_tlsfallback == nil { progedit_tlsfallback = obj.Linklookup(ctxt, "runtime.read_tls_fallback", 0) } // MOVW LR, R11 p.As = AMOVW p.From.Type = obj.TYPE_REG p.From.Reg = REGLINK p.To.Type = obj.TYPE_REG p.To.Reg = REGTMP // BL runtime.read_tls_fallback(SB) p = obj.Appendp(ctxt, p) p.As = ABL p.To.Type = obj.TYPE_BRANCH p.To.Sym = progedit_tlsfallback p.To.Offset = 0 // MOVW R11, LR p = obj.Appendp(ctxt, p) p.As = AMOVW p.From.Type = obj.TYPE_REG p.From.Reg = REGTMP p.To.Type = obj.TYPE_REG p.To.Reg = REGLINK break } } // Otherwise, MRC/MCR instructions need no further treatment. p.As = AWORD } // Rewrite float constants to values stored in memory. switch p.As { case AMOVF: if p.From.Type == obj.TYPE_FCONST && chipfloat5(ctxt, p.From.Val.(float64)) < 0 && (chipzero5(ctxt, p.From.Val.(float64)) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) { f32 := float32(p.From.Val.(float64)) i32 := math.Float32bits(f32) literal := fmt.Sprintf("$f32.%08x", i32) s := obj.Linklookup(ctxt, literal, 0) p.From.Type = obj.TYPE_MEM p.From.Sym = s p.From.Name = obj.NAME_EXTERN p.From.Offset = 0 } case AMOVD: if p.From.Type == obj.TYPE_FCONST && chipfloat5(ctxt, p.From.Val.(float64)) < 0 && (chipzero5(ctxt, p.From.Val.(float64)) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) { i64 := math.Float64bits(p.From.Val.(float64)) literal := fmt.Sprintf("$f64.%016x", i64) s := obj.Linklookup(ctxt, literal, 0) p.From.Type = obj.TYPE_MEM p.From.Sym = s p.From.Name = obj.NAME_EXTERN p.From.Offset = 0 } } if ctxt.Flag_dynlink { rewriteToUseGot(ctxt, p) } }
func opirr(ctxt *obj.Link, a obj.As) uint32 { switch a { case AADD: return SP(1, 0) case AADDU: return SP(1, 1) case ASGT: return SP(1, 2) case ASGTU: return SP(1, 3) case AAND: return SP(1, 4) case AOR: return SP(1, 5) case AXOR: return SP(1, 6) case ALUI: return SP(1, 7) case ASLL: return OP(0, 0) case ASRL: return OP(0, 2) case ASRA: return OP(0, 3) case AADDV: return SP(3, 0) case AADDVU: return SP(3, 1) case AJMP: return SP(0, 2) case AJAL, obj.ADUFFZERO, obj.ADUFFCOPY: return SP(0, 3) case ABEQ: return SP(0, 4) case -ABEQ: return SP(2, 4) /* likely */ case ABNE: return SP(0, 5) case -ABNE: return SP(2, 5) /* likely */ case ABGEZ: return SP(0, 1) | BCOND(0, 1) case -ABGEZ: return SP(0, 1) | BCOND(0, 3) /* likely */ case ABGEZAL: return SP(0, 1) | BCOND(2, 1) case -ABGEZAL: return SP(0, 1) | BCOND(2, 3) /* likely */ case ABGTZ: return SP(0, 7) case -ABGTZ: return SP(2, 7) /* likely */ case ABLEZ: return SP(0, 6) case -ABLEZ: return SP(2, 6) /* likely */ case ABLTZ: return SP(0, 1) | BCOND(0, 0) case -ABLTZ: return SP(0, 1) | BCOND(0, 2) /* likely */ case ABLTZAL: return SP(0, 1) | BCOND(2, 0) case -ABLTZAL: return SP(0, 1) | BCOND(2, 2) /* likely */ case ABFPT: return SP(2, 1) | (257 << 16) case -ABFPT: return SP(2, 1) | (259 << 16) /* likely */ case ABFPF: return SP(2, 1) | (256 << 16) case -ABFPF: return SP(2, 1) | (258 << 16) /* likely */ case AMOVB, AMOVBU: return SP(5, 0) case AMOVH, AMOVHU: return SP(5, 1) case AMOVW, AMOVWU: return SP(5, 3) case AMOVV: return SP(7, 7) case AMOVF: return SP(7, 1) case AMOVD: return SP(7, 5) case AMOVWL: return SP(5, 2) case AMOVWR: return SP(5, 6) case AMOVVL: return SP(5, 4) case AMOVVR: return SP(5, 5) case ABREAK: return SP(5, 7) case -AMOVWL: return SP(4, 2) case -AMOVWR: return SP(4, 6) case -AMOVVL: return SP(3, 2) case -AMOVVR: return SP(3, 3) case -AMOVB: return SP(4, 0) case -AMOVBU: return SP(4, 4) case -AMOVH: return SP(4, 1) case -AMOVHU: return SP(4, 5) case -AMOVW: return SP(4, 3) case -AMOVWU: return SP(4, 7) case -AMOVV: return SP(6, 7) case -AMOVF: return SP(6, 1) case -AMOVD: return SP(6, 5) case ASLLV: return OP(7, 0) case ASRLV: return OP(7, 2) case ASRAV: return OP(7, 3) case -ASLLV: return OP(7, 4) case -ASRLV: return OP(7, 6) case -ASRAV: return OP(7, 7) } if a < 0 { ctxt.Diag("bad irr opcode -%v", obj.Aconv(-a)) } else { ctxt.Diag("bad irr opcode %v", obj.Aconv(a)) } return 0 }
// Rewrite p, if necessary, to access global data via the global offset table. func rewriteToUseGot(ctxt *obj.Link, p *obj.Prog) { var add, lea, mov obj.As var reg int16 if p.Mode == 64 { add = AADDQ lea = ALEAQ mov = AMOVQ reg = REG_R15 } else { add = AADDL lea = ALEAL mov = AMOVL reg = REG_CX } if p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO { // ADUFFxxx $offset // becomes // $MOV runtime.duffxxx@GOT, $reg // $ADD $offset, $reg // CALL $reg var sym *obj.LSym if p.As == obj.ADUFFZERO { sym = obj.Linklookup(ctxt, "runtime.duffzero", 0) } else { sym = obj.Linklookup(ctxt, "runtime.duffcopy", 0) } offset := p.To.Offset p.As = mov p.From.Type = obj.TYPE_MEM p.From.Name = obj.NAME_GOTREF p.From.Sym = sym p.To.Type = obj.TYPE_REG p.To.Reg = reg p.To.Offset = 0 p.To.Sym = nil p1 := obj.Appendp(ctxt, p) p1.As = add p1.From.Type = obj.TYPE_CONST p1.From.Offset = offset p1.To.Type = obj.TYPE_REG p1.To.Reg = reg p2 := obj.Appendp(ctxt, p1) p2.As = obj.ACALL p2.To.Type = obj.TYPE_REG p2.To.Reg = reg } // We only care about global data: NAME_EXTERN means a global // symbol in the Go sense, and p.Sym.Local is true for a few // internally defined symbols. if p.As == lea && p.From.Type == obj.TYPE_MEM && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local { // $LEA sym, Rx becomes $MOV $sym, Rx which will be rewritten below p.As = mov p.From.Type = obj.TYPE_ADDR } if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local { // $MOV $sym, Rx becomes $MOV sym@GOT, Rx // $MOV $sym+<off>, Rx becomes $MOV sym@GOT, Rx; $LEA <off>(Rx), Rx // On 386 only, more complicated things like PUSHL $sym become $MOV sym@GOT, CX; PUSHL CX cmplxdest := false pAs := p.As var dest obj.Addr if p.To.Type != obj.TYPE_REG || pAs != mov { if p.Mode == 64 { ctxt.Diag("do not know how to handle LEA-type insn to non-register in %v with -dynlink", p) } cmplxdest = true dest = p.To p.As = mov p.To.Type = obj.TYPE_REG p.To.Reg = REG_CX p.To.Sym = nil p.To.Name = obj.NAME_NONE } p.From.Type = obj.TYPE_MEM p.From.Name = obj.NAME_GOTREF q := p if p.From.Offset != 0 { q = obj.Appendp(ctxt, p) q.As = lea q.From.Type = obj.TYPE_MEM q.From.Reg = p.To.Reg q.From.Offset = p.From.Offset q.To = p.To p.From.Offset = 0 } if cmplxdest { q = obj.Appendp(ctxt, q) q.As = pAs q.To = dest q.From.Type = obj.TYPE_REG q.From.Reg = REG_CX } } if p.From3 != nil && p.From3.Name == obj.NAME_EXTERN { ctxt.Diag("don't know how to handle %v with -dynlink", p) } var source *obj.Addr // MOVx sym, Ry becomes $MOV sym@GOT, R15; MOVx (R15), Ry // MOVx Ry, sym becomes $MOV sym@GOT, R15; MOVx Ry, (R15) // An addition may be inserted between the two MOVs if there is an offset. if p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local { if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local { ctxt.Diag("cannot handle NAME_EXTERN on both sides in %v with -dynlink", p) } source = &p.From } else if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local { source = &p.To } else { return } if p.As == obj.ACALL { // When dynlinking on 386, almost any call might end up being a call // to a PLT, so make sure the GOT pointer is loaded into BX. // RegTo2 is set on the replacement call insn to stop it being // processed when it is in turn passed to progedit. if p.Mode == 64 || (p.To.Sym != nil && p.To.Sym.Local) || p.RegTo2 != 0 { return } p1 := obj.Appendp(ctxt, p) p2 := obj.Appendp(ctxt, p1) p1.As = ALEAL p1.From.Type = obj.TYPE_MEM p1.From.Name = obj.NAME_STATIC p1.From.Sym = obj.Linklookup(ctxt, "_GLOBAL_OFFSET_TABLE_", 0) p1.To.Type = obj.TYPE_REG p1.To.Reg = REG_BX p2.As = p.As p2.Scond = p.Scond p2.From = p.From p2.From3 = p.From3 p2.Reg = p.Reg p2.To = p.To // p.To.Type was set to TYPE_BRANCH above, but that makes checkaddr // in ../pass.go complain, so set it back to TYPE_MEM here, until p2 // itself gets passed to progedit. p2.To.Type = obj.TYPE_MEM p2.RegTo2 = 1 obj.Nopout(p) return } if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ARET || p.As == obj.AJMP { return } if source.Type != obj.TYPE_MEM { ctxt.Diag("don't know how to handle %v with -dynlink", p) } p1 := obj.Appendp(ctxt, p) p2 := obj.Appendp(ctxt, p1) p1.As = mov p1.From.Type = obj.TYPE_MEM p1.From.Sym = source.Sym p1.From.Name = obj.NAME_GOTREF p1.To.Type = obj.TYPE_REG p1.To.Reg = reg p2.As = p.As p2.From = p.From p2.To = p.To if p.From.Name == obj.NAME_EXTERN { p2.From.Reg = reg p2.From.Name = obj.NAME_NONE p2.From.Sym = nil } else if p.To.Name == obj.NAME_EXTERN { p2.To.Reg = reg p2.To.Name = obj.NAME_NONE p2.To.Sym = nil } else { return } obj.Nopout(p) }
func vregoff(ctxt *obj.Link, a *obj.Addr) int64 { ctxt.Instoffset = 0 aclass(ctxt, a) return ctxt.Instoffset }
func xfol(ctxt *obj.Link, p *obj.Prog, last **obj.Prog) { var q *obj.Prog var r *obj.Prog var i int loop: if p == nil { return } a := p.As if a == AB { q = p.Pcond if q != nil && q.As != obj.ATEXT { p.Mark |= FOLL p = q if p.Mark&FOLL == 0 { goto loop } } } if p.Mark&FOLL != 0 { i = 0 q = p for ; i < 4; i, q = i+1, q.Link { if q == *last || q == nil { break } a = q.As if a == obj.ANOP { i-- continue } if a == AB || (a == obj.ARET && q.Scond == C_SCOND_NONE) || a == ARFE || a == obj.AUNDEF { goto copy } if q.Pcond == nil || (q.Pcond.Mark&FOLL != 0) { continue } if a != ABEQ && a != ABNE { continue } copy: for { r = ctxt.NewProg() *r = *p if r.Mark&FOLL == 0 { fmt.Printf("can't happen 1\n") } r.Mark |= FOLL if p != q { p = p.Link (*last).Link = r *last = r continue } (*last).Link = r *last = r if a == AB || (a == obj.ARET && q.Scond == C_SCOND_NONE) || a == ARFE || a == obj.AUNDEF { return } r.As = ABNE if a == ABNE { r.As = ABEQ } r.Pcond = p.Link r.Link = p.Pcond if r.Link.Mark&FOLL == 0 { xfol(ctxt, r.Link, last) } if r.Pcond.Mark&FOLL == 0 { fmt.Printf("can't happen 2\n") } return } } a = AB q = ctxt.NewProg() q.As = a q.Lineno = p.Lineno q.To.Type = obj.TYPE_BRANCH q.To.Offset = p.Pc q.Pcond = p p = q } p.Mark |= FOLL (*last).Link = p *last = p if a == AB || (a == obj.ARET && p.Scond == C_SCOND_NONE) || a == ARFE || a == obj.AUNDEF { return } if p.Pcond != nil { if a != ABL && a != ABX && p.Link != nil { q = obj.Brchain(ctxt, p.Link) if a != obj.ATEXT { if q != nil && (q.Mark&FOLL != 0) { p.As = relinv(a) p.Link = p.Pcond p.Pcond = q } } xfol(ctxt, p.Link, last) q = obj.Brchain(ctxt, p.Pcond) if q == nil { q = p.Pcond } if q.Mark&FOLL != 0 { p.Pcond = q return } p = q goto loop } } p = p.Link goto loop }
func preprocess(ctxt *obj.Link, cursym *obj.LSym) { // TODO(minux): add morestack short-cuts with small fixed frame-size. ctxt.Cursym = cursym // a switch for enabling/disabling instruction scheduling nosched := true if cursym.Text == nil || cursym.Text.Link == nil { return } p := cursym.Text textstksiz := p.To.Offset cursym.Args = p.To.Val.(int32) cursym.Locals = int32(textstksiz) /* * find leaf subroutines * strip NOPs * expand RET * expand BECOME pseudo */ if ctxt.Debugvlog != 0 { fmt.Fprintf(ctxt.Bso, "%5.2f noops\n", obj.Cputime()) } ctxt.Bso.Flush() var q *obj.Prog var q1 *obj.Prog for p := cursym.Text; p != nil; p = p.Link { switch p.As { /* too hard, just leave alone */ case obj.ATEXT: q = p p.Mark |= LABEL | LEAF | SYNC if p.Link != nil { p.Link.Mark |= LABEL } /* too hard, just leave alone */ case AMOVW, AMOVV: q = p if p.To.Type == obj.TYPE_REG && p.To.Reg >= REG_SPECIAL { p.Mark |= LABEL | SYNC break } if p.From.Type == obj.TYPE_REG && p.From.Reg >= REG_SPECIAL { p.Mark |= LABEL | SYNC } /* too hard, just leave alone */ case ASYSCALL, AWORD, ATLBWR, ATLBWI, ATLBP, ATLBR: q = p p.Mark |= LABEL | SYNC case ANOR: q = p if p.To.Type == obj.TYPE_REG { if p.To.Reg == REGZERO { p.Mark |= LABEL | SYNC } } case ABGEZAL, ABLTZAL, AJAL, obj.ADUFFZERO, obj.ADUFFCOPY: cursym.Text.Mark &^= LEAF fallthrough case AJMP, ABEQ, ABGEZ, ABGTZ, ABLEZ, ABLTZ, ABNE, ABFPT, ABFPF: if p.As == ABFPT || p.As == ABFPF { // We don't treat ABFPT and ABFPF as branches here, // so that we will always fill nop (0x0) in their // delay slot during assembly. // This is to workaround a kernel FPU emulator bug // where it uses the user stack to simulate the // instruction in the delay slot if it's not 0x0, // and somehow that leads to SIGSEGV when the kernel // jump to the stack. p.Mark |= SYNC } else { p.Mark |= BRANCH } q = p q1 = p.Pcond if q1 != nil { for q1.As == obj.ANOP { q1 = q1.Link p.Pcond = q1 } if q1.Mark&LEAF == 0 { q1.Mark |= LABEL } } //else { // p.Mark |= LABEL //} q1 = p.Link if q1 != nil { q1.Mark |= LABEL } continue case ARET: q = p if p.Link != nil { p.Link.Mark |= LABEL } continue case obj.ANOP: q1 = p.Link q.Link = q1 /* q is non-nop */ q1.Mark |= p.Mark continue default: q = p continue } } autosize := int32(0) var p1 *obj.Prog var p2 *obj.Prog for p := cursym.Text; p != nil; p = p.Link { o := p.As switch o { case obj.ATEXT: autosize = int32(textstksiz + 8) if (p.Mark&LEAF != 0) && autosize <= 8 { autosize = 0 } else if autosize&4 != 0 { autosize += 4 } p.To.Offset = int64(autosize) - 8 if p.From3.Offset&obj.NOSPLIT == 0 { p = stacksplit(ctxt, p, autosize) // emit split check } q = p if autosize != 0 { q = obj.Appendp(ctxt, p) q.As = AADDV q.Lineno = p.Lineno q.From.Type = obj.TYPE_CONST q.From.Offset = int64(-autosize) q.To.Type = obj.TYPE_REG q.To.Reg = REGSP q.Spadj = +autosize } else if cursym.Text.Mark&LEAF == 0 { if cursym.Text.From3.Offset&obj.NOSPLIT != 0 { if ctxt.Debugvlog != 0 { fmt.Fprintf(ctxt.Bso, "save suppressed in: %s\n", cursym.Name) ctxt.Bso.Flush() } cursym.Text.Mark |= LEAF } } if cursym.Text.Mark&LEAF != 0 { cursym.Leaf = true break } q = obj.Appendp(ctxt, q) q.As = AMOVV q.Lineno = p.Lineno q.From.Type = obj.TYPE_REG q.From.Reg = REGLINK q.To.Type = obj.TYPE_MEM q.To.Offset = int64(0) q.To.Reg = REGSP if cursym.Text.From3.Offset&obj.WRAPPER != 0 { // if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame // // MOVV g_panic(g), R1 // BEQ R1, end // MOVV panic_argp(R1), R2 // ADDV $(autosize+8), R29, R3 // BNE R2, R3, end // ADDV $8, R29, R2 // MOVV R2, panic_argp(R1) // end: // NOP // // The NOP is needed to give the jumps somewhere to land. // It is a liblink NOP, not an mips NOP: it encodes to 0 instruction bytes. q = obj.Appendp(ctxt, q) q.As = AMOVV q.From.Type = obj.TYPE_MEM q.From.Reg = REGG q.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic q.To.Type = obj.TYPE_REG q.To.Reg = REG_R1 q = obj.Appendp(ctxt, q) q.As = ABEQ q.From.Type = obj.TYPE_REG q.From.Reg = REG_R1 q.To.Type = obj.TYPE_BRANCH q.Mark |= BRANCH p1 = q q = obj.Appendp(ctxt, q) q.As = AMOVV q.From.Type = obj.TYPE_MEM q.From.Reg = REG_R1 q.From.Offset = 0 // Panic.argp q.To.Type = obj.TYPE_REG q.To.Reg = REG_R2 q = obj.Appendp(ctxt, q) q.As = AADDV q.From.Type = obj.TYPE_CONST q.From.Offset = int64(autosize) + 8 q.Reg = REGSP q.To.Type = obj.TYPE_REG q.To.Reg = REG_R3 q = obj.Appendp(ctxt, q) q.As = ABNE q.From.Type = obj.TYPE_REG q.From.Reg = REG_R2 q.Reg = REG_R3 q.To.Type = obj.TYPE_BRANCH q.Mark |= BRANCH p2 = q q = obj.Appendp(ctxt, q) q.As = AADDV q.From.Type = obj.TYPE_CONST q.From.Offset = 8 q.Reg = REGSP q.To.Type = obj.TYPE_REG q.To.Reg = REG_R2 q = obj.Appendp(ctxt, q) q.As = AMOVV q.From.Type = obj.TYPE_REG q.From.Reg = REG_R2 q.To.Type = obj.TYPE_MEM q.To.Reg = REG_R1 q.To.Offset = 0 // Panic.argp q = obj.Appendp(ctxt, q) q.As = obj.ANOP p1.Pcond = q p2.Pcond = q } case ARET: if p.From.Type == obj.TYPE_CONST { ctxt.Diag("using BECOME (%v) is not supported!", p) break } if p.To.Sym != nil { // retjmp p.As = AJMP p.To.Type = obj.TYPE_BRANCH break } if cursym.Text.Mark&LEAF != 0 { if autosize == 0 { p.As = AJMP p.From = obj.Addr{} p.To.Type = obj.TYPE_MEM p.To.Offset = 0 p.To.Reg = REGLINK p.Mark |= BRANCH break } p.As = AADDV 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 = ctxt.NewProg() q.As = AJMP q.Lineno = p.Lineno q.To.Type = obj.TYPE_MEM q.To.Offset = 0 q.To.Reg = REGLINK q.Mark |= BRANCH q.Spadj = +autosize q.Link = p.Link p.Link = q break } p.As = AMOVV p.From.Type = obj.TYPE_MEM p.From.Offset = 0 p.From.Reg = REGSP p.To.Type = obj.TYPE_REG p.To.Reg = REG_R4 if false { // Debug bad returns q = ctxt.NewProg() q.As = AMOVV q.Lineno = p.Lineno q.From.Type = obj.TYPE_MEM q.From.Offset = 0 q.From.Reg = REG_R4 q.To.Type = obj.TYPE_REG q.To.Reg = REGTMP q.Link = p.Link p.Link = q p = q } if autosize != 0 { q = ctxt.NewProg() q.As = AADDV q.Lineno = p.Lineno 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.Link = p.Link p.Link = q } q1 = ctxt.NewProg() q1.As = AJMP q1.Lineno = p.Lineno q1.To.Type = obj.TYPE_MEM q1.To.Offset = 0 q1.To.Reg = REG_R4 q1.Mark |= BRANCH q1.Spadj = +autosize q1.Link = q.Link q.Link = q1 case AADDV, AADDVU: if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.From.Type == obj.TYPE_CONST { p.Spadj = int32(-p.From.Offset) } } } if nosched { // if we don't do instruction scheduling, simply add // NOP after each branch instruction. for p = cursym.Text; p != nil; p = p.Link { if p.Mark&BRANCH != 0 { addnop(ctxt, p) } } return } // instruction scheduling q = nil // p - 1 q1 = cursym.Text // top of block o := 0 // count of instructions for p = cursym.Text; p != nil; p = p1 { p1 = p.Link o++ if p.Mark&NOSCHED != 0 { if q1 != p { sched(ctxt, q1, q) } for ; p != nil; p = p.Link { if p.Mark&NOSCHED == 0 { break } q = p } p1 = p q1 = p o = 0 continue } if p.Mark&(LABEL|SYNC) != 0 { if q1 != p { sched(ctxt, q1, q) } q1 = p o = 1 } if p.Mark&(BRANCH|SYNC) != 0 { sched(ctxt, q1, p) q1 = p1 o = 0 } if o >= NSCHED { sched(ctxt, q1, p) q1 = p1 o = 0 } q = p } }