func follow(ctxt *liblink.Link, s *liblink.LSym) { var firstp *liblink.Prog var lastp *liblink.Prog ctxt.Cursym = s firstp = ctxt.Prg() lastp = firstp xfol(ctxt, s.Text, &lastp) lastp.Link = nil s.Text = firstp.Link }
func linkcase(casep *liblink.Prog) { var p *liblink.Prog for p = casep; p != nil; p = p.Link { if p.As == ABCASE { for ; p != nil && p.As == ABCASE; p = p.Link { p.Pcrel = casep } break } } }
// Append code to p to load g into cx. // Overwrites p with the first instruction (no first appendp). // Overwriting p is unusual but it lets use this in both the // prologue (caller must call appendp first) and in the epilogue. // Returns last new instruction. func load_g_cx(ctxt *liblink.Link, p *liblink.Prog) *liblink.Prog { var next *liblink.Prog p.As = AMOVL p.From.Typ = D_INDIR + D_TLS p.From.Offset = 0 p.To.Typ = D_CX next = p.Link progedit(ctxt, p) for p.Link != next { p = p.Link } if p.From.Index == D_TLS { p.From.Scale = 2 } return p }
func readprog(b *bufio.Reader, p *liblink.Prog) { if !undef[p] { panic("double-def") } delete(undef, p) p.Pc = rdint(b) p.Lineno = int(rdint(b)) p.Link = rdprog(b) p.As = int(rdint(b)) p.Reg = int(rdint(b)) p.Scond = int(rdint(b)) p.Width = int8(rdint(b)) readaddr(b, &p.From) readaddr(b, &p.To) }
func Pconv(p *liblink.Prog) string { var str string var fp string switch p.As { case ADATA: str = fmt.Sprintf("%.5d (%v)\t%v\t%v/%d,%v", p.Pc, p.Line(), Aconv(p.As), Dconv(p, 0, &p.From), p.From.Scale, Dconv(p, 0, &p.To)) case ATEXT: if p.From.Scale != 0 { str = fmt.Sprintf("%.5d (%v)\t%v\t%v,%d,%v", p.Pc, p.Line(), Aconv(p.As), Dconv(p, 0, &p.From), p.From.Scale, Dconv(p, fmtLong, &p.To)) break } str = fmt.Sprintf("%.5d (%v)\t%v\t%v,%v", p.Pc, p.Line(), Aconv(p.As), Dconv(p, 0, &p.From), Dconv(p, fmtLong, &p.To)) default: str = fmt.Sprintf("%.5d (%v)\t%v\t%v,%v", p.Pc, p.Line(), Aconv(p.As), Dconv(p, 0, &p.From), Dconv(p, 0, &p.To)) break } fp += str return fp }
func xfol(ctxt *liblink.Link, p *liblink.Prog, last **liblink.Prog) { var q *liblink.Prog var r *liblink.Prog var a int var i int loop: if p == nil { return } a = p.As if a == AB { q = p.Pcond if q != nil && q.As != 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; (func() { i++; q = q.Link })() { if q == *last || q == nil { break } a = q.As if a == ANOP { i-- continue } if a == AB || (a == ARET && q.Scond == C_SCOND_NONE) || a == ARFE || a == AUNDEF { goto copy } if q.Pcond == nil || (q.Pcond.Mark&FOLL != 0) { continue } if a != ABEQ && a != ABNE { continue } copy: for { r = ctxt.Prg() *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 == ARET && q.Scond == C_SCOND_NONE) || a == ARFE || a == 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.Prg() q.As = a q.Lineno = p.Lineno q.To.Typ = D_BRANCH q.To.Offset = p.Pc q.Pcond = p p = q } p.Mark |= FOLL (*last).Link = p *last = p if a == AB || (a == ARET && p.Scond == C_SCOND_NONE) || a == ARFE || a == AUNDEF { return } if p.Pcond != nil { if a != ABL && a != ABX && p.Link != nil { q = liblink.Brchain(ctxt, p.Link) if a != ATEXT && a != ABCASE { if q != nil && (q.Mark&FOLL != 0) { p.As = relinv(a) p.Link = p.Pcond p.Pcond = q } } xfol(ctxt, p.Link, last) q = liblink.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 progedit(ctxt *liblink.Link, p *liblink.Prog) { var literal string var s *liblink.LSym var tlsfallback *liblink.LSym p.From.Class = 0 p.To.Class = 0 // Rewrite B/BL to symbol as D_BRANCH. switch p.As { case AB, ABL, ADUFFZERO, ADUFFCOPY: if p.To.Typ == D_OREG && (p.To.Name == D_EXTERN || p.To.Name == D_STATIC) && p.To.Sym != nil { p.To.Typ = D_BRANCH } break } // Replace TLS register fetches on older ARM procesors. switch p.As { // If the instruction matches MRC 15, 0, <reg>, C13, C0, 3, replace it. case AMRC: if ctxt.Goarm < 7 && p.To.Offset&0xffff0fff == 0xee1d0f70 { tlsfallback = liblink.Linklookup(ctxt, "runtime.read_tls_fallback", 0) // BL runtime.read_tls_fallback(SB) p.As = ABL p.To.Typ = D_BRANCH p.To.Sym = tlsfallback p.To.Offset = 0 } else { // Otherwise, MRC/MCR instructions need no further treatment. p.As = AWORD } break } // Rewrite float constants to values stored in memory. switch p.As { case AMOVF: if p.From.Typ == D_FCONST && chipfloat5(ctxt, p.From.U.Dval) < 0 && (chipzero5(ctxt, p.From.U.Dval) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) { var i32 uint32 var f32 float32 f32 = float32(p.From.U.Dval) i32 = math.Float32bits(f32) literal = fmt.Sprintf("$f32.%08x", i32) s = liblink.Linklookup(ctxt, literal, 0) if s.Typ == 0 { s.Typ = liblink.SRODATA liblink.Adduint32(ctxt, s, i32) s.Reachable = 0 } p.From.Typ = D_OREG p.From.Sym = s p.From.Name = D_EXTERN p.From.Offset = 0 } case AMOVD: if p.From.Typ == D_FCONST && chipfloat5(ctxt, p.From.U.Dval) < 0 && (chipzero5(ctxt, p.From.U.Dval) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) { var i64 uint64 i64 = math.Float64bits(p.From.U.Dval) literal = fmt.Sprintf("$f64.%016x", uint64(i64)) s = liblink.Linklookup(ctxt, literal, 0) if s.Typ == 0 { s.Typ = liblink.SRODATA liblink.Adduint64(ctxt, s, i64) s.Reachable = 0 } p.From.Typ = D_OREG p.From.Sym = s p.From.Name = D_EXTERN p.From.Offset = 0 } break } if ctxt.Flag_shared != 0 { // Shared libraries use R_ARM_TLS_IE32 instead of // R_ARM_TLS_LE32, replacing the link time constant TLS offset in // runtime.tlsg with an address to a GOT entry containing the // offset. Rewrite $runtime.tlsg(SB) to runtime.tlsg(SB) to // compensate. if ctxt.Tlsg == nil { ctxt.Tlsg = liblink.Linklookup(ctxt, "runtime.tlsg", 0) } if p.From.Typ == D_CONST && p.From.Name == D_EXTERN && p.From.Sym == ctxt.Tlsg { p.From.Typ = D_OREG } if p.To.Typ == D_CONST && p.To.Name == D_EXTERN && p.To.Sym == ctxt.Tlsg { p.To.Typ = D_OREG } } }
func settextflag(p *liblink.Prog, f int) { p.Reg = f }
func addstacksplit(ctxt *liblink.Link, cursym *liblink.LSym) { var p *liblink.Prog var q *liblink.Prog var autoffset int64 var deltasp int64 var a int if ctxt.Symmorestack[0] == nil { ctxt.Symmorestack[0] = liblink.Linklookup(ctxt, "runtime.morestack", 0) ctxt.Symmorestack[1] = liblink.Linklookup(ctxt, "runtime.morestack_noctxt", 0) } if ctxt.Headtype == liblink.Hplan9 && ctxt.Plan9privates == nil { ctxt.Plan9privates = liblink.Linklookup(ctxt, "_privates", 0) } ctxt.Cursym = cursym if cursym.Text == nil || cursym.Text.Link == nil { return } p = cursym.Text autoffset = p.To.Offset if autoffset < 0 { autoffset = 0 } cursym.Locals = autoffset cursym.Args = p.To.Offset2 q = nil if p.From.Scale&liblink.NOSPLIT == 0 || (p.From.Scale&liblink.WRAPPER != 0) { p = liblink.Appendp(ctxt, p) p = load_g_cx(ctxt, p) // load g into CX } if cursym.Text.From.Scale&liblink.NOSPLIT == 0 { p = stacksplit(ctxt, p, autoffset, bool2int(cursym.Text.From.Scale&liblink.NEEDCTXT == 0), &q) // emit split check } if autoffset != 0 { p = liblink.Appendp(ctxt, p) p.As = AADJSP p.From.Typ = D_CONST p.From.Offset = autoffset p.Spadj = autoffset } else { // zero-byte stack adjustment. // Insert a fake non-zero adjustment so that stkcheck can // recognize the end of the stack-splitting prolog. p = liblink.Appendp(ctxt, p) p.As = ANOP p.Spadj = -ctxt.Arch.Ptrsize p = liblink.Appendp(ctxt, p) p.As = ANOP p.Spadj = ctxt.Arch.Ptrsize } if q != nil { q.Pcond = p } deltasp = autoffset if cursym.Text.From.Scale&liblink.WRAPPER != 0 { // g->panicwrap += autoffset + ctxt->arch->ptrsize; p = liblink.Appendp(ctxt, p) p.As = AADDL p.From.Typ = D_CONST p.From.Offset = autoffset + ctxt.Arch.Ptrsize p.To.Typ = D_INDIR + D_CX p.To.Offset = 2 * ctxt.Arch.Ptrsize } if ctxt.Debugzerostack != 0 && autoffset != 0 && cursym.Text.From.Scale&liblink.NOSPLIT == 0 { // 8l -Z means zero the stack frame on entry. // This slows down function calls but can help avoid // false positives in garbage collection. p = liblink.Appendp(ctxt, p) p.As = AMOVL p.From.Typ = D_SP p.To.Typ = D_DI p = liblink.Appendp(ctxt, p) p.As = AMOVL p.From.Typ = D_CONST p.From.Offset = autoffset / 4 p.To.Typ = D_CX p = liblink.Appendp(ctxt, p) p.As = AMOVL p.From.Typ = D_CONST p.From.Offset = 0 p.To.Typ = D_AX p = liblink.Appendp(ctxt, p) p.As = AREP p = liblink.Appendp(ctxt, p) p.As = ASTOSL } for ; p != nil; p = p.Link { a = p.From.Typ if a == D_AUTO { p.From.Offset += deltasp } if a == D_PARAM { p.From.Offset += deltasp + 4 } a = p.To.Typ if a == D_AUTO { p.To.Offset += deltasp } if a == D_PARAM { p.To.Offset += deltasp + 4 } switch p.As { default: continue case APUSHL, APUSHFL: deltasp += 4 p.Spadj = 4 continue case APUSHW, APUSHFW: deltasp += 2 p.Spadj = 2 continue case APOPL, APOPFL: deltasp -= 4 p.Spadj = -4 continue case APOPW, APOPFW: deltasp -= 2 p.Spadj = -2 continue case ARET: break } if autoffset != deltasp { ctxt.Diag("unbalanced PUSH/POP") } if cursym.Text.From.Scale&liblink.WRAPPER != 0 { p = load_g_cx(ctxt, p) p = liblink.Appendp(ctxt, p) // g->panicwrap -= autoffset + ctxt->arch->ptrsize; p.As = ASUBL p.From.Typ = D_CONST p.From.Offset = autoffset + ctxt.Arch.Ptrsize p.To.Typ = D_INDIR + D_CX p.To.Offset = 2 * ctxt.Arch.Ptrsize p = liblink.Appendp(ctxt, p) p.As = ARET } if autoffset != 0 { p.As = AADJSP p.From.Typ = D_CONST p.From.Offset = -autoffset p.Spadj = -autoffset p = liblink.Appendp(ctxt, p) p.As = ARET // If there are instructions following // this ARET, they come from a branch // with the same stackframe, so undo // the cleanup. p.Spadj = +autoffset } if p.To.Sym != nil { // retjmp p.As = AJMP } } }
func nopout(p *liblink.Prog) { p.As = ANOP p.From.Typ = D_NONE p.To.Typ = D_NONE }
func addstacksplit(ctxt *liblink.Link, cursym *liblink.LSym) { var p *liblink.Prog var pl *liblink.Prog var q *liblink.Prog var q1 *liblink.Prog var q2 *liblink.Prog var o int var autosize int64 var autoffset int64 autosize = 0 if ctxt.Symmorestack[0] == nil { ctxt.Symmorestack[0] = liblink.Linklookup(ctxt, "runtime.morestack", 0) ctxt.Symmorestack[1] = liblink.Linklookup(ctxt, "runtime.morestack_noctxt", 0) } q = nil ctxt.Cursym = cursym if cursym.Text == nil || cursym.Text.Link == nil { return } softfloat(ctxt, cursym) p = cursym.Text autoffset = p.To.Offset if autoffset < 0 { autoffset = 0 } cursym.Locals = autoffset cursym.Args = p.To.Offset2 if ctxt.Debugzerostack != 0 { if autoffset != 0 && p.Reg&liblink.NOSPLIT == 0 { // MOVW $4(R13), R1 p = liblink.Appendp(ctxt, p) p.As = AMOVW p.From.Typ = D_CONST p.From.Reg = 13 p.From.Offset = 4 p.To.Typ = D_REG p.To.Reg = 1 // MOVW $n(R13), R2 p = liblink.Appendp(ctxt, p) p.As = AMOVW p.From.Typ = D_CONST p.From.Reg = 13 p.From.Offset = 4 + autoffset p.To.Typ = D_REG p.To.Reg = 2 // MOVW $0, R3 p = liblink.Appendp(ctxt, p) p.As = AMOVW p.From.Typ = D_CONST p.From.Offset = 0 p.To.Typ = D_REG p.To.Reg = 3 // L: // MOVW.nil R3, 0(R1) +4 // CMP R1, R2 // BNE L pl = liblink.Appendp(ctxt, p) p = pl p.As = AMOVW p.From.Typ = D_REG p.From.Reg = 3 p.To.Typ = D_OREG p.To.Reg = 1 p.To.Offset = 4 p.Scond |= C_PBIT p = liblink.Appendp(ctxt, p) p.As = ACMP p.From.Typ = D_REG p.From.Reg = 1 p.Reg = 2 p = liblink.Appendp(ctxt, p) p.As = ABNE p.To.Typ = D_BRANCH p.Pcond = pl } } /* * find leaf subroutines * strip NOPs * expand RET * expand BECOME pseudo */ for p = cursym.Text; p != nil; p = p.Link { switch p.As { case ACASE: if ctxt.Flag_shared != 0 { linkcase(p) } case ATEXT: p.Mark |= LEAF case ARET: break case ADIV, ADIVU, AMOD, AMODU: q = p if ctxt.Sym_div == nil { initdiv(ctxt) } cursym.Text.Mark &^= LEAF continue case ANOP: q1 = p.Link q.Link = q1 /* q is non-nop */ if q1 != nil { q1.Mark |= p.Mark } continue case ABL, ABX, ADUFFZERO, ADUFFCOPY: cursym.Text.Mark &^= LEAF fallthrough case ABCASE, AB, ABEQ, ABNE, ABCS, ABHS, ABCC, ABLO, ABMI, ABPL, ABVS, ABVC, ABHI, ABLS, ABGE, ABLT, ABGT, ABLE: q1 = p.Pcond if q1 != nil { for q1.As == ANOP { q1 = q1.Link p.Pcond = q1 } } break } q = p } for p = cursym.Text; p != nil; p = p.Link { o = p.As switch o { case ATEXT: autosize = p.To.Offset + 4 if autosize <= 4 { if cursym.Text.Mark&LEAF != 0 { p.To.Offset = -4 autosize = 0 } } if autosize == 0 && cursym.Text.Mark&LEAF == 0 { if ctxt.Debugvlog != 0 { fmt.Fprintf(ctxt.Bso, "save suppressed in: %s\n", cursym.Name) liblink.Bflush(ctxt.Bso) } cursym.Text.Mark |= LEAF } if cursym.Text.Mark&LEAF != 0 { cursym.Leaf = 1 if autosize == 0 { break } } if p.Reg&liblink.NOSPLIT == 0 { p = stacksplit(ctxt, p, autosize, bool2int(cursym.Text.Reg&liblink.NEEDCTXT == 0)) // emit split check } // MOVW.W R14,$-autosize(SP) p = liblink.Appendp(ctxt, p) p.As = AMOVW p.Scond |= C_WBIT p.From.Typ = D_REG p.From.Reg = REGLINK p.To.Typ = D_OREG p.To.Offset = -autosize p.To.Reg = REGSP p.Spadj = autosize if cursym.Text.Reg&liblink.WRAPPER != 0 { // g->panicwrap += autosize; // MOVW panicwrap_offset(g), R3 // ADD $autosize, R3 // MOVW R3 panicwrap_offset(g) p = liblink.Appendp(ctxt, p) p.As = AMOVW p.From.Typ = D_OREG p.From.Reg = REGG p.From.Offset = 2 * ctxt.Arch.Ptrsize p.To.Typ = D_REG p.To.Reg = 3 p = liblink.Appendp(ctxt, p) p.As = AADD p.From.Typ = D_CONST p.From.Offset = autosize p.To.Typ = D_REG p.To.Reg = 3 p = liblink.Appendp(ctxt, p) p.As = AMOVW p.From.Typ = D_REG p.From.Reg = 3 p.To.Typ = D_OREG p.To.Reg = REGG p.To.Offset = 2 * ctxt.Arch.Ptrsize } case ARET: nocache_obj5(p) if cursym.Text.Mark&LEAF != 0 { if autosize == 0 { p.As = AB p.From = zprg_obj5.From if p.To.Sym != nil { // retjmp p.To.Typ = D_BRANCH } else { p.To.Typ = D_OREG p.To.Offset = 0 p.To.Reg = REGLINK } break } } if cursym.Text.Reg&liblink.WRAPPER != 0 { var scond int // Preserve original RET's cond, to allow RET.EQ // in the implementation of reflect.call. scond = p.Scond p.Scond = C_SCOND_NONE // g->panicwrap -= autosize; // MOVW panicwrap_offset(g), R3 // SUB $autosize, R3 // MOVW R3 panicwrap_offset(g) p.As = AMOVW p.From.Typ = D_OREG p.From.Reg = REGG p.From.Offset = 2 * ctxt.Arch.Ptrsize p.To.Typ = D_REG p.To.Reg = 3 p = liblink.Appendp(ctxt, p) p.As = ASUB p.From.Typ = D_CONST p.From.Offset = autosize p.To.Typ = D_REG p.To.Reg = 3 p = liblink.Appendp(ctxt, p) p.As = AMOVW p.From.Typ = D_REG p.From.Reg = 3 p.To.Typ = D_OREG p.To.Reg = REGG p.To.Offset = 2 * ctxt.Arch.Ptrsize p = liblink.Appendp(ctxt, p) p.Scond = scond } p.As = AMOVW p.Scond |= C_PBIT p.From.Typ = D_OREG p.From.Offset = autosize p.From.Reg = REGSP p.To.Typ = D_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 = liblink.Appendp(ctxt, p) q2.As = AB q2.To.Typ = D_BRANCH q2.To.Sym = p.To.Sym p.To.Sym = nil p = q2 } case AADD: if p.From.Typ == D_CONST && p.From.Reg == NREG && p.To.Typ == D_REG && p.To.Reg == REGSP { p.Spadj = -p.From.Offset } case ASUB: if p.From.Typ == D_CONST && p.From.Reg == NREG && p.To.Typ == D_REG && p.To.Reg == REGSP { p.Spadj = p.From.Offset } case ADIV, ADIVU, AMOD, AMODU: if ctxt.Debugdivmod != 0 { break } if p.From.Typ != D_REG { break } if p.To.Typ != D_REG { break } q1 = p /* MOV a,4(SP) */ p = liblink.Appendp(ctxt, p) p.As = AMOVW p.Lineno = q1.Lineno p.From.Typ = D_REG p.From.Reg = q1.From.Reg p.To.Typ = D_OREG p.To.Reg = REGSP p.To.Offset = 4 /* MOV b,REGTMP */ p = liblink.Appendp(ctxt, p) p.As = AMOVW p.Lineno = q1.Lineno p.From.Typ = D_REG p.From.Reg = q1.Reg if q1.Reg == NREG { p.From.Reg = q1.To.Reg } p.To.Typ = D_REG p.To.Reg = REGTMP p.To.Offset = 0 /* CALL appropriate */ p = liblink.Appendp(ctxt, p) p.As = ABL p.Lineno = q1.Lineno p.To.Typ = D_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 break } /* MOV REGTMP, b */ p = liblink.Appendp(ctxt, p) p.As = AMOVW p.Lineno = q1.Lineno p.From.Typ = D_REG p.From.Reg = REGTMP p.From.Offset = 0 p.To.Typ = D_REG p.To.Reg = q1.To.Reg /* ADD $8,SP */ p = liblink.Appendp(ctxt, p) p.As = AADD p.Lineno = q1.Lineno p.From.Typ = D_CONST p.From.Reg = NREG p.From.Offset = 8 p.Reg = NREG p.To.Typ = D_REG p.To.Reg = REGSP p.Spadj = -8 /* Keep saved LR at 0(SP) after SP change. */ /* MOVW 0(SP), REGTMP; MOVW REGTMP, -8!(SP) */ /* TODO: Remove SP adjustments; see issue 6699. */ q1.As = AMOVW q1.From.Typ = D_OREG q1.From.Reg = REGSP q1.From.Offset = 0 q1.Reg = NREG q1.To.Typ = D_REG q1.To.Reg = REGTMP /* SUB $8,SP */ q1 = liblink.Appendp(ctxt, q1) q1.As = AMOVW q1.From.Typ = D_REG q1.From.Reg = REGTMP q1.Reg = NREG q1.To.Typ = D_OREG q1.To.Reg = REGSP q1.To.Offset = -8 q1.Scond |= C_WBIT q1.Spadj = 8 case AMOVW: if (p.Scond&C_WBIT != 0) && p.To.Typ == D_OREG && p.To.Reg == REGSP { p.Spadj = -p.To.Offset } if (p.Scond&C_PBIT != 0) && p.From.Typ == D_OREG && p.From.Reg == REGSP && p.To.Reg != REGPC { p.Spadj = -p.From.Offset } if p.From.Typ == D_CONST && p.From.Reg == REGSP && p.To.Typ == D_REG && p.To.Reg == REGSP { p.Spadj = -p.From.Offset } break } } }
func nocache_obj5(p *liblink.Prog) { p.Optab = 0 p.From.Class = 0 p.To.Class = 0 }
func progedit(ctxt *liblink.Link, p *liblink.Prog) { var literal string var s *liblink.LSym var q *liblink.Prog // See obj6.c for discussion of TLS. if canuselocaltls(ctxt) { // Reduce TLS initial exec model to TLS local exec model. // Sequences like // MOVL TLS, BX // ... off(BX)(TLS*1) ... // become // NOP // ... off(TLS) ... if p.As == AMOVL && p.From.Typ == D_TLS && D_AX <= p.To.Typ && p.To.Typ <= D_DI { p.As = ANOP p.From.Typ = D_NONE p.To.Typ = D_NONE } if p.From.Index == D_TLS && D_INDIR+D_AX <= p.From.Typ && p.From.Typ <= D_INDIR+D_DI { p.From.Typ = D_INDIR + D_TLS p.From.Scale = 0 p.From.Index = D_NONE } if p.To.Index == D_TLS && D_INDIR+D_AX <= p.To.Typ && p.To.Typ <= D_INDIR+D_DI { p.To.Typ = D_INDIR + D_TLS p.To.Scale = 0 p.To.Index = D_NONE } } else { // As a courtesy to the C compilers, rewrite TLS local exec load as TLS initial exec load. // The instruction // MOVL off(TLS), BX // becomes the sequence // MOVL TLS, BX // MOVL off(BX)(TLS*1), BX // This allows the C compilers to emit references to m and g using the direct off(TLS) form. if p.As == AMOVL && p.From.Typ == D_INDIR+D_TLS && D_AX <= p.To.Typ && p.To.Typ <= D_DI { q = liblink.Appendp(ctxt, p) q.As = p.As q.From = p.From q.From.Typ = D_INDIR + p.To.Typ q.From.Index = D_TLS q.From.Scale = 2 // TODO: use 1 q.To = p.To p.From.Typ = D_TLS p.From.Index = D_NONE p.From.Offset = 0 } } // TODO: Remove. if ctxt.Headtype == liblink.Hplan9 { if p.From.Scale == 1 && p.From.Index == D_TLS { p.From.Scale = 2 } if p.To.Scale == 1 && p.To.Index == D_TLS { p.To.Scale = 2 } } // Rewrite CALL/JMP/RET to symbol as D_BRANCH. switch p.As { case ACALL, AJMP, ARET: if (p.To.Typ == D_EXTERN || p.To.Typ == D_STATIC) && p.To.Sym != nil { p.To.Typ = D_BRANCH } break } // Rewrite float constants to values stored in memory. switch p.As { case AFMOVF, AFADDF, AFSUBF, AFSUBRF, AFMULF, AFDIVF, AFDIVRF, AFCOMF, AFCOMFP, AMOVSS, AADDSS, ASUBSS, AMULSS, ADIVSS, ACOMISS, AUCOMISS: if p.From.Typ == D_FCONST { var i32 uint32 var f32 float32 f32 = float32(p.From.U.Dval) i32 = math.Float32bits(f32) literal = fmt.Sprintf("$f32.%08x", uint32(i32)) s = liblink.Linklookup(ctxt, literal, 0) if s.Typ == 0 { s.Typ = liblink.SRODATA liblink.Adduint32(ctxt, s, i32) s.Reachable = 0 } p.From.Typ = D_EXTERN p.From.Sym = s p.From.Offset = 0 } case AFMOVD, AFADDD, AFSUBD, AFSUBRD, AFMULD, AFDIVD, AFDIVRD, AFCOMD, AFCOMDP, AMOVSD, AADDSD, ASUBSD, AMULSD, ADIVSD, ACOMISD, AUCOMISD: if p.From.Typ == D_FCONST { var i64 uint64 i64 = math.Float64bits(p.From.U.Dval) literal = fmt.Sprintf("$f64.%016x", uint64(i64)) s = liblink.Linklookup(ctxt, literal, 0) if s.Typ == 0 { s.Typ = liblink.SRODATA liblink.Adduint64(ctxt, s, i64) s.Reachable = 0 } p.From.Typ = D_EXTERN p.From.Sym = s p.From.Offset = 0 } break } }
func xfol(ctxt *liblink.Link, p *liblink.Prog, last **liblink.Prog) { var q *liblink.Prog var i int var a int loop: if p == nil { return } if p.As == AJMP { q = p.Pcond if q != nil && q.As != ATEXT { /* mark instruction as done and continue layout at target of jump */ p.Mark = 1 p = q if p.Mark == 0 { goto loop } } } if p.Mark != 0 { /* * p goes here, but already used it elsewhere. * copy up to 4 instructions or else branch to other copy. */ i = 0 q = p for ; i < 4; (func() { i++; q = q.Link })() { if q == nil { break } if q == *last { break } a = q.As if a == ANOP { i-- continue } if nofollow(a) || pushpop(a) != 0 { break // NOTE(rsc): arm does goto copy } if q.Pcond == nil || q.Pcond.Mark != 0 { continue } if a == ACALL || a == ALOOP { continue } for { if p.As == ANOP { p = p.Link continue } q = liblink.Copyp(ctxt, p) p = p.Link q.Mark = 1 (*last).Link = q *last = q if q.As != a || q.Pcond == nil || q.Pcond.Mark != 0 { continue } q.As = relinv(q.As) p = q.Pcond q.Pcond = q.Link q.Link = p xfol(ctxt, q.Link, last) p = q.Link if p.Mark != 0 { return } goto loop /* */ } } q = ctxt.Prg() q.As = AJMP q.Lineno = p.Lineno q.To.Typ = D_BRANCH q.To.Offset = p.Pc q.Pcond = p p = q } /* emit p */ p.Mark = 1 (*last).Link = p *last = p a = p.As /* continue loop with what comes after p */ if nofollow(a) { return } if p.Pcond != nil && a != ACALL { /* * some kind of conditional branch. * recurse to follow one path. * continue loop on the other. */ q = liblink.Brchain(ctxt, p.Pcond) if q != nil { p.Pcond = q } q = liblink.Brchain(ctxt, p.Link) if q != nil { p.Link = q } if p.From.Typ == D_CONST { if p.From.Offset == 1 { /* * expect conditional jump to be taken. * rewrite so that's the fall-through case. */ p.As = relinv(a) q = p.Link p.Link = p.Pcond p.Pcond = q } } else { q = p.Link if q.Mark != 0 { if a != ALOOP { p.As = relinv(a) p.Link = p.Pcond p.Pcond = q } } } xfol(ctxt, p.Link, last) if p.Pcond.Mark != 0 { return } p = p.Pcond goto loop } p = p.Link goto loop }
// Append code to p to check for stack split. // Appends to (does not overwrite) p. // Assumes g is in CX. // Returns last new instruction. // On return, *jmpok is the instruction that should jump // to the stack frame allocation if no split is needed. func stacksplit(ctxt *liblink.Link, p *liblink.Prog, framesize int64, noctxt int, jmpok **liblink.Prog) *liblink.Prog { var q *liblink.Prog var q1 *liblink.Prog var arg int if ctxt.Debugstack != 0 { // 8l -K means check not only for stack // overflow but stack underflow. // On underflow, INT 3 (breakpoint). // Underflow itself is rare but this also // catches out-of-sync stack guard info. p = liblink.Appendp(ctxt, p) p.As = ACMPL p.From.Typ = D_INDIR + D_CX p.From.Offset = 4 p.To.Typ = D_SP p = liblink.Appendp(ctxt, p) p.As = AJCC p.To.Typ = D_BRANCH p.To.Offset = 4 q1 = p p = liblink.Appendp(ctxt, p) p.As = AINT p.From.Typ = D_CONST p.From.Offset = 3 p = liblink.Appendp(ctxt, p) p.As = ANOP q1.Pcond = p } q1 = nil if framesize <= liblink.StackSmall { // small stack: SP <= stackguard // CMPL SP, stackguard p = liblink.Appendp(ctxt, p) p.As = ACMPL p.From.Typ = D_SP p.To.Typ = D_INDIR + D_CX } else if framesize <= liblink.StackBig { // large stack: SP-framesize <= stackguard-StackSmall // LEAL -(framesize-StackSmall)(SP), AX // CMPL AX, stackguard p = liblink.Appendp(ctxt, p) p.As = ALEAL p.From.Typ = D_INDIR + D_SP p.From.Offset = -(framesize - liblink.StackSmall) p.To.Typ = D_AX p = liblink.Appendp(ctxt, p) p.As = ACMPL p.From.Typ = D_AX p.To.Typ = D_INDIR + D_CX } else { // Such a large stack we need to protect against wraparound // if SP is close to zero. // SP-stackguard+StackGuard <= framesize + (StackGuard-StackSmall) // The +StackGuard on both sides is required to keep the left side positive: // SP is allowed to be slightly below stackguard. See stack.h. // // Preemption sets stackguard to StackPreempt, a very large value. // That breaks the math above, so we have to check for that explicitly. // MOVL stackguard, CX // CMPL CX, $StackPreempt // JEQ label-of-call-to-morestack // LEAL StackGuard(SP), AX // SUBL stackguard, AX // CMPL AX, $(framesize+(StackGuard-StackSmall)) p = liblink.Appendp(ctxt, p) p.As = AMOVL p.From.Typ = D_INDIR + D_CX p.From.Offset = 0 p.To.Typ = D_SI p = liblink.Appendp(ctxt, p) p.As = ACMPL p.From.Typ = D_SI p.To.Typ = D_CONST p.To.Offset = int64(uint32(liblink.StackPreempt & 0xFFFFFFFF)) p = liblink.Appendp(ctxt, p) p.As = AJEQ p.To.Typ = D_BRANCH q1 = p p = liblink.Appendp(ctxt, p) p.As = ALEAL p.From.Typ = D_INDIR + D_SP p.From.Offset = liblink.StackGuard p.To.Typ = D_AX p = liblink.Appendp(ctxt, p) p.As = ASUBL p.From.Typ = D_SI p.From.Offset = 0 p.To.Typ = D_AX p = liblink.Appendp(ctxt, p) p.As = ACMPL p.From.Typ = D_AX p.To.Typ = D_CONST p.To.Offset = framesize + (liblink.StackGuard - liblink.StackSmall) } // common p = liblink.Appendp(ctxt, p) p.As = AJHI p.To.Typ = D_BRANCH p.To.Offset = 4 q = p p = liblink.Appendp(ctxt, p) // save frame size in DI p.As = AMOVL p.To.Typ = D_DI p.From.Typ = D_CONST // If we ask for more stack, we'll get a minimum of StackMin bytes. // We need a stack frame large enough to hold the top-of-stack data, // the function arguments+results, our caller's PC, our frame, // a word for the return PC of the next call, and then the StackLimit bytes // that must be available on entry to any function called from a function // that did a stack check. If StackMin is enough, don't ask for a specific // amount: then we can use the custom functions and save a few // instructions. if int64(liblink.StackTop+ctxt.Cursym.Text.To.Offset2)+ctxt.Arch.Ptrsize+framesize+ctxt.Arch.Ptrsize+liblink.StackLimit >= liblink.StackMin { p.From.Offset = (framesize + 7) &^ 7 } arg = ctxt.Cursym.Text.To.Offset2 if arg == 1 { // special marker for known 0 arg = 0 } if arg&3 != 0 { ctxt.Diag("misaligned argument size in stack split") } p = liblink.Appendp(ctxt, p) // save arg size in AX p.As = AMOVL p.To.Typ = D_AX p.From.Typ = D_CONST p.From.Offset = int64(arg) p = liblink.Appendp(ctxt, p) p.As = ACALL p.To.Typ = D_BRANCH p.To.Sym = ctxt.Symmorestack[noctxt] p = liblink.Appendp(ctxt, p) p.As = AJMP p.To.Typ = D_BRANCH p.Pcond = ctxt.Cursym.Text.Link if q != nil { q.Pcond = p.Link } if q1 != nil { q1.Pcond = q.Link } *jmpok = q return p }
func softfloat(ctxt *liblink.Link, cursym *liblink.LSym) { var p *liblink.Prog var next *liblink.Prog var symsfloat *liblink.LSym var wasfloat int if ctxt.Goarm > 5 { return } symsfloat = liblink.Linklookup(ctxt, "_sfloat", 0) wasfloat = 0 for p = cursym.Text; p != nil; p = p.Link { if p.Pcond != nil { p.Pcond.Mark |= LABEL } } for p = cursym.Text; p != nil; p = p.Link { switch p.As { case AMOVW: if p.To.Typ == D_FREG || p.From.Typ == D_FREG { 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.Prg() *next = *p // BL _sfloat(SB) *p = zprg_obj5 p.Ctxt = ctxt p.Link = next p.As = ABL p.To.Typ = D_BRANCH p.To.Sym = symsfloat p.Lineno = next.Lineno p = next wasfloat = 1 } continue notsoft: wasfloat = 0 } }
func addstacksplit(ctxt *liblink.Link, cursym *liblink.LSym) { var p *liblink.Prog var q *liblink.Prog var q1 *liblink.Prog var autoffset int64 var deltasp int64 var a int var pcsize int var i uint32 var textstksiz int64 var textarg int64 if ctxt.Tlsg == nil { ctxt.Tlsg = liblink.Linklookup(ctxt, "runtime.tlsg", 0) } if ctxt.Symmorestack[0] == nil { if len(morename) > len(ctxt.Symmorestack) { log.Fatalf("Link.symmorestack needs at least %d elements", len(morename)) } for i = 0; i < uint32(len(morename)); i++ { ctxt.Symmorestack[i] = liblink.Linklookup(ctxt, morename[i], 0) } } if ctxt.Headtype == liblink.Hplan9 && ctxt.Plan9privates == nil { ctxt.Plan9privates = liblink.Linklookup(ctxt, "_privates", 0) } ctxt.Cursym = cursym if cursym.Text == nil || cursym.Text.Link == nil { return } p = cursym.Text parsetextconst(p.To.Offset, &textstksiz, &textarg) autoffset = textstksiz if autoffset < 0 { autoffset = 0 } cursym.Args = int(p.To.Offset >> 32) cursym.Locals = textstksiz if autoffset < liblink.StackSmall && p.From.Scale&liblink.NOSPLIT == 0 { for q = p; q != nil; q = q.Link { if q.As == ACALL { goto noleaf } if (q.As == ADUFFCOPY || q.As == ADUFFZERO) && autoffset >= liblink.StackSmall-8 { goto noleaf } } p.From.Scale |= liblink.NOSPLIT noleaf: } q = nil if p.From.Scale&liblink.NOSPLIT == 0 || (p.From.Scale&liblink.WRAPPER != 0) { p = liblink.Appendp(ctxt, p) p = load_g_cx(ctxt, p) // load g into CX } if cursym.Text.From.Scale&liblink.NOSPLIT == 0 { p = stacksplit(ctxt, p, autoffset, textarg, bool2int(cursym.Text.From.Scale&liblink.NEEDCTXT == 0), &q) // emit split check } if autoffset != 0 { if autoffset%int64(ctxt.Arch.Regsize) != 0 { ctxt.Diag("unaligned stack size %d", autoffset) } p = liblink.Appendp(ctxt, p) p.As = AADJSP p.From.Typ = D_CONST p.From.Offset = autoffset p.Spadj = autoffset } else { // zero-byte stack adjustment. // Insert a fake non-zero adjustment so that stkcheck can // recognize the end of the stack-splitting prolog. p = liblink.Appendp(ctxt, p) p.As = ANOP p.Spadj = -ctxt.Arch.Ptrsize p = liblink.Appendp(ctxt, p) p.As = ANOP p.Spadj = ctxt.Arch.Ptrsize } if q != nil { q.Pcond = p } deltasp = autoffset if cursym.Text.From.Scale&liblink.WRAPPER != 0 { // g->panicwrap += autoffset + ctxt->arch->regsize; p = liblink.Appendp(ctxt, p) p.As = AADDL p.From.Typ = D_CONST p.From.Offset = autoffset + int64(ctxt.Arch.Regsize) indir_cx(ctxt, &p.To) p.To.Offset = 2 * ctxt.Arch.Ptrsize } if ctxt.Debugstack > 1 && autoffset != 0 { // 6l -K -K means double-check for stack overflow // even after calling morestack and even if the // function is marked as nosplit. p = liblink.Appendp(ctxt, p) p.As = AMOVQ indir_cx(ctxt, &p.From) p.From.Offset = 0 p.To.Typ = D_BX p = liblink.Appendp(ctxt, p) p.As = ASUBQ p.From.Typ = D_CONST p.From.Offset = liblink.StackSmall + 32 p.To.Typ = D_BX p = liblink.Appendp(ctxt, p) p.As = ACMPQ p.From.Typ = D_SP p.To.Typ = D_BX p = liblink.Appendp(ctxt, p) p.As = AJHI p.To.Typ = D_BRANCH q1 = p p = liblink.Appendp(ctxt, p) p.As = AINT p.From.Typ = D_CONST p.From.Offset = 3 p = liblink.Appendp(ctxt, p) p.As = ANOP q1.Pcond = p } if ctxt.Debugzerostack != 0 && autoffset != 0 && cursym.Text.From.Scale&liblink.NOSPLIT == 0 { // 6l -Z means zero the stack frame on entry. // This slows down function calls but can help avoid // false positives in garbage collection. p = liblink.Appendp(ctxt, p) p.As = AMOVQ p.From.Typ = D_SP p.To.Typ = D_DI p = liblink.Appendp(ctxt, p) p.As = AMOVQ p.From.Typ = D_CONST p.From.Offset = autoffset / 8 p.To.Typ = D_CX p = liblink.Appendp(ctxt, p) p.As = AMOVQ p.From.Typ = D_CONST p.From.Offset = 0 p.To.Typ = D_AX p = liblink.Appendp(ctxt, p) p.As = AREP p = liblink.Appendp(ctxt, p) p.As = ASTOSQ } for ; p != nil; p = p.Link { pcsize = p.Mode / 8 a = p.From.Typ if a == D_AUTO { p.From.Offset += deltasp } if a == D_PARAM { p.From.Offset += deltasp + int64(pcsize) } a = p.To.Typ if a == D_AUTO { p.To.Offset += deltasp } if a == D_PARAM { p.To.Offset += deltasp + int64(pcsize) } switch p.As { default: continue case APUSHL, APUSHFL: deltasp += 4 p.Spadj = 4 continue case APUSHQ, APUSHFQ: deltasp += 8 p.Spadj = 8 continue case APUSHW, APUSHFW: deltasp += 2 p.Spadj = 2 continue case APOPL, APOPFL: deltasp -= 4 p.Spadj = -4 continue case APOPQ, APOPFQ: deltasp -= 8 p.Spadj = -8 continue case APOPW, APOPFW: deltasp -= 2 p.Spadj = -2 continue case ARET: break } if autoffset != deltasp { ctxt.Diag("unbalanced PUSH/POP") } if cursym.Text.From.Scale&liblink.WRAPPER != 0 { p = load_g_cx(ctxt, p) p = liblink.Appendp(ctxt, p) // g->panicwrap -= autoffset + ctxt->arch->regsize; p.As = ASUBL p.From.Typ = D_CONST p.From.Offset = autoffset + int64(ctxt.Arch.Regsize) indir_cx(ctxt, &p.To) p.To.Offset = 2 * ctxt.Arch.Ptrsize p = liblink.Appendp(ctxt, p) p.As = ARET } if autoffset != 0 { p.As = AADJSP p.From.Typ = D_CONST p.From.Offset = -autoffset p.Spadj = -autoffset p = liblink.Appendp(ctxt, p) p.As = ARET // If there are instructions following // this ARET, they come from a branch // with the same stackframe, so undo // the cleanup. p.Spadj = +autoffset } if p.To.Sym != nil { // retjmp p.As = AJMP } } } func indir_cx(ctxt *liblink.Link, a *liblink.Addr) { if ctxt.Headtype == liblink.Hnacl { a.Typ = D_INDIR + D_R15 a.Index = D_CX a.Scale = 1 return } a.Typ = D_INDIR + D_CX } // Append code to p to load g into cx. // Overwrites p with the first instruction (no first appendp). // Overwriting p is unusual but it lets use this in both the // prologue (caller must call appendp first) and in the epilogue. // Returns last new instruction. func load_g_cx(ctxt *liblink.Link, p *liblink.Prog) *liblink.Prog { var next *liblink.Prog p.As = AMOVQ if ctxt.Arch.Ptrsize == 4 { p.As = AMOVL } p.From.Typ = D_INDIR + D_TLS p.From.Offset = 0 p.To.Typ = D_CX next = p.Link progedit(ctxt, p) for p.Link != next { p = p.Link } if p.From.Index == D_TLS { p.From.Scale = 2 } return p } // Append code to p to check for stack split. // Appends to (does not overwrite) p. // Assumes g is in CX. // Returns last new instruction. // On return, *jmpok is the instruction that should jump // to the stack frame allocation if no split is needed. func stacksplit(ctxt *liblink.Link, p *liblink.Prog, framesize int64, textarg int64, noctxt int, jmpok **liblink.Prog) *liblink.Prog { var q *liblink.Prog var q1 *liblink.Prog var moreconst1 int64 var moreconst2 int64 var i uint32 var cmp int var lea int var mov int var sub int cmp = ACMPQ lea = ALEAQ mov = AMOVQ sub = ASUBQ if ctxt.Headtype == liblink.Hnacl { cmp = ACMPL lea = ALEAL mov = AMOVL sub = ASUBL } if ctxt.Debugstack != 0 { // 6l -K means check not only for stack // overflow but stack underflow. // On underflow, INT 3 (breakpoint). // Underflow itself is rare but this also // catches out-of-sync stack guard info p = liblink.Appendp(ctxt, p) p.As = cmp indir_cx(ctxt, &p.From) p.From.Offset = 8 p.To.Typ = D_SP p = liblink.Appendp(ctxt, p) p.As = AJHI p.To.Typ = D_BRANCH p.To.Offset = 4 q1 = p p = liblink.Appendp(ctxt, p) p.As = AINT p.From.Typ = D_CONST p.From.Offset = 3 p = liblink.Appendp(ctxt, p) p.As = ANOP q1.Pcond = p } q1 = nil if framesize <= liblink.StackSmall { // small stack: SP <= stackguard // CMPQ SP, stackguard p = liblink.Appendp(ctxt, p) p.As = cmp p.From.Typ = D_SP indir_cx(ctxt, &p.To) } else if framesize <= liblink.StackBig { // large stack: SP-framesize <= stackguard-StackSmall // LEAQ -xxx(SP), AX // CMPQ AX, stackguard p = liblink.Appendp(ctxt, p) p.As = lea p.From.Typ = D_INDIR + D_SP p.From.Offset = -(framesize - liblink.StackSmall) p.To.Typ = D_AX p = liblink.Appendp(ctxt, p) p.As = cmp p.From.Typ = D_AX indir_cx(ctxt, &p.To) } else { // Such a large stack we need to protect against wraparound. // If SP is close to zero: // SP-stackguard+StackGuard <= framesize + (StackGuard-StackSmall) // The +StackGuard on both sides is required to keep the left side positive: // SP is allowed to be slightly below stackguard. See stack.h. // // Preemption sets stackguard to StackPreempt, a very large value. // That breaks the math above, so we have to check for that explicitly. // MOVQ stackguard, CX // CMPQ CX, $StackPreempt // JEQ label-of-call-to-morestack // LEAQ StackGuard(SP), AX // SUBQ CX, AX // CMPQ AX, $(framesize+(StackGuard-StackSmall)) p = liblink.Appendp(ctxt, p) p.As = mov indir_cx(ctxt, &p.From) p.From.Offset = 0 p.To.Typ = D_SI p = liblink.Appendp(ctxt, p) p.As = cmp p.From.Typ = D_SI p.To.Typ = D_CONST p.To.Offset = liblink.StackPreempt p = liblink.Appendp(ctxt, p) p.As = AJEQ p.To.Typ = D_BRANCH q1 = p p = liblink.Appendp(ctxt, p) p.As = lea p.From.Typ = D_INDIR + D_SP p.From.Offset = liblink.StackGuard p.To.Typ = D_AX p = liblink.Appendp(ctxt, p) p.As = sub p.From.Typ = D_SI p.To.Typ = D_AX p = liblink.Appendp(ctxt, p) p.As = cmp p.From.Typ = D_AX p.To.Typ = D_CONST p.To.Offset = framesize + (liblink.StackGuard - liblink.StackSmall) } // common p = liblink.Appendp(ctxt, p) p.As = AJHI p.To.Typ = D_BRANCH q = p // If we ask for more stack, we'll get a minimum of StackMin bytes. // We need a stack frame large enough to hold the top-of-stack data, // the function arguments+results, our caller's PC, our frame, // a word for the return PC of the next call, and then the StackLimit bytes // that must be available on entry to any function called from a function // that did a stack check. If StackMin is enough, don't ask for a specific // amount: then we can use the custom functions and save a few // instructions. moreconst1 = 0 if liblink.StackTop+textarg+ctxt.Arch.Ptrsize+framesize+ctxt.Arch.Ptrsize+liblink.StackLimit >= liblink.StackMin { moreconst1 = framesize } moreconst2 = textarg if moreconst2 == 1 { // special marker moreconst2 = 0 } if moreconst2&7 != 0 { ctxt.Diag("misaligned argument size in stack split") } // 4 varieties varieties (const1==0 cross const2==0) // and 6 subvarieties of (const1==0 and const2!=0) p = liblink.Appendp(ctxt, p) if moreconst1 == 0 && moreconst2 == 0 { p.As = ACALL p.To.Typ = D_BRANCH p.To.Sym = ctxt.Symmorestack[0*2+noctxt] } else if moreconst1 != 0 && moreconst2 == 0 { p.As = AMOVL p.From.Typ = D_CONST p.From.Offset = moreconst1 p.To.Typ = D_AX p = liblink.Appendp(ctxt, p) p.As = ACALL p.To.Typ = D_BRANCH p.To.Sym = ctxt.Symmorestack[1*2+noctxt] } else if moreconst1 == 0 && moreconst2 <= 48 && moreconst2%8 == 0 { i = uint32(moreconst2/8 + 3) p.As = ACALL p.To.Typ = D_BRANCH p.To.Sym = ctxt.Symmorestack[i*2+uint32(noctxt)] } else if moreconst1 == 0 && moreconst2 != 0 { p.As = AMOVL p.From.Typ = D_CONST p.From.Offset = moreconst2 p.To.Typ = D_AX p = liblink.Appendp(ctxt, p) p.As = ACALL p.To.Typ = D_BRANCH p.To.Sym = ctxt.Symmorestack[2*2+noctxt] } else { // Pass framesize and argsize. p.As = AMOVQ p.From.Typ = D_CONST p.From.Offset = int64(uint64(moreconst2) << 32) p.From.Offset |= moreconst1 p.To.Typ = D_AX p = liblink.Appendp(ctxt, p) p.As = ACALL p.To.Typ = D_BRANCH p.To.Sym = ctxt.Symmorestack[3*2+noctxt] } p = liblink.Appendp(ctxt, p) p.As = AJMP p.To.Typ = D_BRANCH p.Pcond = ctxt.Cursym.Text.Link if q != nil { q.Pcond = p.Link } if q1 != nil { q1.Pcond = q.Link } *jmpok = q return p } func follow(ctxt *liblink.Link, s *liblink.LSym) { var firstp *liblink.Prog var lastp *liblink.Prog ctxt.Cursym = s firstp = ctxt.Prg() lastp = firstp xfol(ctxt, s.Text, &lastp) lastp.Link = nil s.Text = firstp.Link } func nofollow(a int) bool { switch a { case AJMP, ARET, AIRETL, AIRETQ, AIRETW, ARETFL, ARETFQ, ARETFW, AUNDEF: return true } return false } func pushpop(a int) int { switch a { case APUSHL, APUSHFL, APUSHQ, APUSHFQ, APUSHW, APUSHFW, APOPL, APOPFL, APOPQ, APOPFQ, APOPW, APOPFW: return 1 } return 0 } func relinv(a int) int { switch a { case AJEQ: return AJNE case AJNE: return AJEQ case AJLE: return AJGT case AJLS: return AJHI case AJLT: return AJGE case AJMI: return AJPL case AJGE: return AJLT case AJPL: return AJMI case AJGT: return AJLE case AJHI: return AJLS case AJCS: return AJCC case AJCC: return AJCS case AJPS: return AJPC case AJPC: return AJPS case AJOS: return AJOC case AJOC: return AJOS } log.Fatalf("unknown relation: %s", Anames6[a]) return 0 } func xfol(ctxt *liblink.Link, p *liblink.Prog, last **liblink.Prog) { var q *liblink.Prog var i int var a int loop: if p == nil { return } if p.As == AJMP { q = p.Pcond if q != nil && q.As != ATEXT { /* mark instruction as done and continue layout at target of jump */ p.Mark = 1 p = q if p.Mark == 0 { goto loop } } } if p.Mark != 0 { /* * p goes here, but already used it elsewhere. * copy up to 4 instructions or else branch to other copy. */ i = 0 q = p for ; i < 4; (func() { i++; q = q.Link })() { if q == nil { break } if q == *last { break } a = q.As if a == ANOP { i-- continue } if nofollow(a) || pushpop(a) != 0 { break // NOTE(rsc): arm does goto copy } if q.Pcond == nil || q.Pcond.Mark != 0 { continue } if a == ACALL || a == ALOOP { continue } for { if p.As == ANOP { p = p.Link continue } q = liblink.Copyp(ctxt, p) p = p.Link q.Mark = 1 (*last).Link = q *last = q if q.As != a || q.Pcond == nil || q.Pcond.Mark != 0 { continue } q.As = relinv(q.As) p = q.Pcond q.Pcond = q.Link q.Link = p xfol(ctxt, q.Link, last) p = q.Link if p.Mark != 0 { return } goto loop /* */ } } q = ctxt.Prg() q.As = AJMP q.Lineno = p.Lineno q.To.Typ = D_BRANCH q.To.Offset = p.Pc q.Pcond = p p = q } /* emit p */ p.Mark = 1 (*last).Link = p *last = p a = p.As /* continue loop with what comes after p */ if nofollow(a) { return } if p.Pcond != nil && a != ACALL { /* * some kind of conditional branch. * recurse to follow one path. * continue loop on the other. */ q = liblink.Brchain(ctxt, p.Pcond) if q != nil { p.Pcond = q } q = liblink.Brchain(ctxt, p.Link) if q != nil { p.Link = q } if p.From.Typ == D_CONST { if p.From.Offset == 1 { /* * expect conditional jump to be taken. * rewrite so that's the fall-through case. */ p.As = relinv(a) q = p.Link p.Link = p.Pcond p.Pcond = q } } else { q = p.Link if q.Mark != 0 { if a != ALOOP { p.As = relinv(a) p.Link = p.Pcond p.Pcond = q } } } xfol(ctxt, p.Link, last) if p.Pcond.Mark != 0 { return } p = p.Pcond goto loop } p = p.Link goto loop } func prg() *liblink.Prog { var p *liblink.Prog p = new(liblink.Prog) *p = zprg return p } var Linkamd64 = liblink.LinkArch{ Name: "amd64", Thechar: '6', ByteOrder: binary.LittleEndian, Pconv: Pconv, Addstacksplit: addstacksplit, Assemble: span6, Datasize: datasize, Follow: follow, Iscall: iscall, Isdata: isdata, Prg: prg, Progedit: progedit, Settextflag: settextflag, Symtype: symtype, Textflag: textflag, Minlc: 1, Ptrsize: 8, Regsize: 8, D_ADDR: D_ADDR, D_AUTO: D_AUTO, D_BRANCH: D_BRANCH, D_CONST: D_CONST, D_EXTERN: D_EXTERN, D_FCONST: D_FCONST, D_NONE: D_NONE, D_PARAM: D_PARAM, D_SCONST: D_SCONST, D_STATIC: D_STATIC, ACALL: ACALL, ADATA: ADATA, AEND: AEND, AFUNCDATA: AFUNCDATA, AGLOBL: AGLOBL, AJMP: AJMP, ANOP: ANOP, APCDATA: APCDATA, ARET: ARET, ATEXT: ATEXT, ATYPE: ATYPE, AUSEFIELD: AUSEFIELD, } var Linkamd64p32 = liblink.LinkArch{ Name: "amd64p32", Thechar: '6', ByteOrder: binary.LittleEndian, Pconv: Pconv, Addstacksplit: addstacksplit, Assemble: span6, Datasize: datasize, Follow: follow, Iscall: iscall, Isdata: isdata, Prg: prg, Progedit: progedit, Settextflag: settextflag, Symtype: symtype, Textflag: textflag, Minlc: 1, Ptrsize: 4, Regsize: 8, D_ADDR: D_ADDR, D_AUTO: D_AUTO, D_BRANCH: D_BRANCH, D_CONST: D_CONST, D_EXTERN: D_EXTERN, D_FCONST: D_FCONST, D_NONE: D_NONE, D_PARAM: D_PARAM, D_SCONST: D_SCONST, D_STATIC: D_STATIC, ACALL: ACALL, ADATA: ADATA, AEND: AEND, AFUNCDATA: AFUNCDATA, AGLOBL: AGLOBL, AJMP: AJMP, ANOP: ANOP, APCDATA: APCDATA, ARET: ARET, ATEXT: ATEXT, ATYPE: ATYPE, AUSEFIELD: AUSEFIELD, }
func stacksplit(ctxt *liblink.Link, p *liblink.Prog, framesize int64, noctxt int) *liblink.Prog { var arg int // MOVW g_stackguard(g), R1 p = liblink.Appendp(ctxt, p) p.As = AMOVW p.From.Typ = D_OREG p.From.Reg = REGG p.To.Typ = D_REG p.To.Reg = 1 if framesize <= liblink.StackSmall { // small stack: SP < stackguard // CMP stackguard, SP p = liblink.Appendp(ctxt, p) p.As = ACMP p.From.Typ = D_REG p.From.Reg = 1 p.Reg = REGSP } else if framesize <= liblink.StackBig { // large stack: SP-framesize < stackguard-StackSmall // MOVW $-framesize(SP), R2 // CMP stackguard, R2 p = liblink.Appendp(ctxt, p) p.As = AMOVW p.From.Typ = D_CONST p.From.Reg = REGSP p.From.Offset = -framesize p.To.Typ = D_REG p.To.Reg = 2 p = liblink.Appendp(ctxt, p) p.As = ACMP p.From.Typ = D_REG p.From.Reg = 1 p.Reg = 2 } else { // Such a large stack we need to protect against wraparound // if SP is close to zero. // SP-stackguard+StackGuard < framesize + (StackGuard-StackSmall) // The +StackGuard on both sides is required to keep the left side positive: // SP is allowed to be slightly below stackguard. See stack.h. // CMP $StackPreempt, R1 // MOVW.NE $StackGuard(SP), R2 // SUB.NE R1, R2 // MOVW.NE $(framesize+(StackGuard-StackSmall)), R3 // CMP.NE R3, R2 p = liblink.Appendp(ctxt, p) p.As = ACMP p.From.Typ = D_CONST p.From.Offset = int64(uint32(liblink.StackPreempt & 0xFFFFFFFF)) p.Reg = 1 p = liblink.Appendp(ctxt, p) p.As = AMOVW p.From.Typ = D_CONST p.From.Reg = REGSP p.From.Offset = liblink.StackGuard p.To.Typ = D_REG p.To.Reg = 2 p.Scond = C_SCOND_NE p = liblink.Appendp(ctxt, p) p.As = ASUB p.From.Typ = D_REG p.From.Reg = 1 p.To.Typ = D_REG p.To.Reg = 2 p.Scond = C_SCOND_NE p = liblink.Appendp(ctxt, p) p.As = AMOVW p.From.Typ = D_CONST p.From.Offset = framesize + (liblink.StackGuard - liblink.StackSmall) p.To.Typ = D_REG p.To.Reg = 3 p.Scond = C_SCOND_NE p = liblink.Appendp(ctxt, p) p.As = ACMP p.From.Typ = D_REG p.From.Reg = 3 p.Reg = 2 p.Scond = C_SCOND_NE } // MOVW.LS $framesize, R1 p = liblink.Appendp(ctxt, p) p.As = AMOVW p.Scond = C_SCOND_LS p.From.Typ = D_CONST p.From.Offset = framesize p.To.Typ = D_REG p.To.Reg = 1 // MOVW.LS $args, R2 p = liblink.Appendp(ctxt, p) p.As = AMOVW p.Scond = C_SCOND_LS p.From.Typ = D_CONST arg = ctxt.Cursym.Text.To.Offset2 if arg == 1 { // special marker for known 0 arg = 0 } if arg&3 != 0 { ctxt.Diag("misaligned argument size in stack split") } p.From.Offset = int64(arg) p.To.Typ = D_REG p.To.Reg = 2 // MOVW.LS R14, R3 p = liblink.Appendp(ctxt, p) p.As = AMOVW p.Scond = C_SCOND_LS p.From.Typ = D_REG p.From.Reg = REGLINK p.To.Typ = D_REG p.To.Reg = 3 // BL.LS runtime.morestack(SB) // modifies LR, returns with LO still asserted p = liblink.Appendp(ctxt, p) p.As = ABL p.Scond = C_SCOND_LS p.To.Typ = D_BRANCH p.To.Sym = ctxt.Symmorestack[noctxt] // BLS start p = liblink.Appendp(ctxt, p) p.As = ABLS p.To.Typ = D_BRANCH p.Pcond = ctxt.Cursym.Text.Link return p }
func progedit(ctxt *liblink.Link, p *liblink.Prog) { var literal string var s *liblink.LSym var q *liblink.Prog // 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 8(AX)(TLS*1), CX // load m 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 8(TLS), CX // load m into CX // // The 2-instruction and 1-instruction forms correspond roughly to // ELF TLS initial exec mode and ELF TLS local exec mode, respectively. // // We applies this rewrite on systems that support the 1-instruction form. // The decision is made using only the operating system (and probably // the -shared flag, eventually), 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. if canuselocaltls(ctxt) { // Reduce TLS initial exec model to TLS local exec model. // 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.Typ == D_TLS && D_AX <= p.To.Typ && p.To.Typ <= D_R15 && ctxt.Headtype != liblink.Hsolaris { nopout(p) } if p.From.Index == D_TLS && D_INDIR+D_AX <= p.From.Typ && p.From.Typ <= D_INDIR+D_R15 { p.From.Typ = D_INDIR + D_TLS p.From.Scale = 0 p.From.Index = D_NONE } if p.To.Index == D_TLS && D_INDIR+D_AX <= p.To.Typ && p.To.Typ <= D_INDIR+D_R15 { p.To.Typ = D_INDIR + D_TLS p.To.Scale = 0 p.To.Index = D_NONE } } else { // As a courtesy to the C compilers, rewrite TLS local exec load as TLS initial exec load. // The instruction // MOVQ off(TLS), BX // becomes the sequence // MOVQ TLS, BX // MOVQ off(BX)(TLS*1), BX // This allows the C compilers to emit references to m and g using the direct off(TLS) form. if (p.As == AMOVQ || p.As == AMOVL) && p.From.Typ == D_INDIR+D_TLS && D_AX <= p.To.Typ && p.To.Typ <= D_R15 { q = liblink.Appendp(ctxt, p) q.As = p.As q.From = p.From q.From.Typ = D_INDIR + p.To.Typ q.From.Index = D_TLS q.From.Scale = 2 // TODO: use 1 q.To = p.To p.From.Typ = D_TLS p.From.Index = D_NONE p.From.Offset = 0 } } // TODO: Remove. if ctxt.Headtype == liblink.Hwindows || ctxt.Headtype == liblink.Hplan9 { if p.From.Scale == 1 && p.From.Index == D_TLS { p.From.Scale = 2 } if p.To.Scale == 1 && p.To.Index == D_TLS { p.To.Scale = 2 } } if ctxt.Headtype == liblink.Hnacl { nacladdr(ctxt, p, &p.From) nacladdr(ctxt, p, &p.To) } // Maintain information about code generation mode. if ctxt.Mode == 0 { ctxt.Mode = 64 } p.Mode = ctxt.Mode switch p.As { case AMODE: if p.From.Typ == D_CONST || p.From.Typ == D_INDIR+D_NONE { switch int(p.From.Offset) { case 16, 32, 64: ctxt.Mode = int(p.From.Offset) break } } nopout(p) break } // Rewrite CALL/JMP/RET to symbol as D_BRANCH. switch p.As { case ACALL, AJMP, ARET: if (p.To.Typ == D_EXTERN || p.To.Typ == D_STATIC) && p.To.Sym != nil { p.To.Typ = D_BRANCH } break } // Rewrite float constants to values stored in memory. switch p.As { case AFMOVF, AFADDF, AFSUBF, AFSUBRF, AFMULF, AFDIVF, AFDIVRF, AFCOMF, AFCOMFP, AMOVSS, AADDSS, ASUBSS, AMULSS, ADIVSS, ACOMISS, AUCOMISS: if p.From.Typ == D_FCONST { var i32 uint32 var f32 float32 f32 = float32(p.From.U.Dval) i32 = math.Float32bits(f32) literal = fmt.Sprintf("$f32.%08x", uint32(i32)) s = liblink.Linklookup(ctxt, literal, 0) if s.Typ == 0 { s.Typ = liblink.SRODATA liblink.Adduint32(ctxt, s, i32) s.Reachable = 0 } p.From.Typ = D_EXTERN p.From.Sym = s p.From.Offset = 0 } case AFMOVD, AFADDD, AFSUBD, AFSUBRD, AFMULD, AFDIVD, AFDIVRD, AFCOMD, AFCOMDP, AMOVSD, AADDSD, ASUBSD, AMULSD, ADIVSD, ACOMISD, AUCOMISD: if p.From.Typ == D_FCONST { var i64 uint64 i64 = math.Float64bits(p.From.U.Dval) literal = fmt.Sprintf("$f64.%016x", uint64(i64)) s = liblink.Linklookup(ctxt, literal, 0) if s.Typ == 0 { s.Typ = liblink.SRODATA liblink.Adduint64(ctxt, s, i64) s.Reachable = 0 } p.From.Typ = D_EXTERN p.From.Sym = s p.From.Offset = 0 } break } }
func Pconv(p *liblink.Prog) string { var str string var sc string var fp string var a int var s int a = p.As s = p.Scond sc = extra[s&C_SCOND] if s&C_SBIT != 0 { sc += ".S" } if s&C_PBIT != 0 { sc += ".P" } if s&C_WBIT != 0 { sc += ".W" } if s&C_UBIT != 0 { /* ambiguous with FBIT */ sc += ".U" } if a == AMOVM { if p.From.Typ == D_CONST { str = fmt.Sprintf("%.5d (%v)\t%v%s\t%v,%v", p.Pc, p.Line(), Aconv(a), sc, RAconv(&p.From), Dconv(p, 0, &p.To)) } else if p.To.Typ == D_CONST { str = fmt.Sprintf("%.5d (%v)\t%v%s\t%v,%v", p.Pc, p.Line(), Aconv(a), sc, Dconv(p, 0, &p.From), RAconv(&p.To)) } else { str = fmt.Sprintf("%.5d (%v)\t%v%s\t%v,%v", p.Pc, p.Line(), Aconv(a), sc, Dconv(p, 0, &p.From), Dconv(p, 0, &p.To)) } } else if a == ADATA { str = fmt.Sprintf("%.5d (%v)\t%v\t%v/%d,%v", p.Pc, p.Line(), Aconv(a), Dconv(p, 0, &p.From), p.Reg, Dconv(p, 0, &p.To)) } else if p.As == ATEXT { str = fmt.Sprintf("%.5d (%v)\t%v\t%v,%d,%v", p.Pc, p.Line(), Aconv(a), Dconv(p, 0, &p.From), p.Reg, Dconv(p, 0, &p.To)) } else if p.Reg == NREG { str = fmt.Sprintf("%.5d (%v)\t%v%s\t%v,%v", p.Pc, p.Line(), Aconv(a), sc, Dconv(p, 0, &p.From), Dconv(p, 0, &p.To)) } else if p.From.Typ != D_FREG { str = fmt.Sprintf("%.5d (%v)\t%v%s\t%v,R%d,%v", p.Pc, p.Line(), Aconv(a), sc, Dconv(p, 0, &p.From), p.Reg, Dconv(p, 0, &p.To)) } else { str = fmt.Sprintf("%.5d (%v)\t%v%s\t%v,F%d,%v", p.Pc, p.Line(), Aconv(a), sc, Dconv(p, 0, &p.From), p.Reg, Dconv(p, 0, &p.To)) } fp += str return fp }