diff options
Diffstat (limited to 'vendor/github.com/google/gops/internal/obj/arm/obj5.go')
| -rw-r--r-- | vendor/github.com/google/gops/internal/obj/arm/obj5.go | 1055 |
1 files changed, 1055 insertions, 0 deletions
diff --git a/vendor/github.com/google/gops/internal/obj/arm/obj5.go b/vendor/github.com/google/gops/internal/obj/arm/obj5.go new file mode 100644 index 00000000..2c4e39b7 --- /dev/null +++ b/vendor/github.com/google/gops/internal/obj/arm/obj5.go @@ -0,0 +1,1055 @@ +// Derived from Inferno utils/5c/swt.c +// https://bitbucket.org/inferno-os/inferno-os/src/default/utils/5c/swt.c +// +// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved. +// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net) +// Portions Copyright © 1997-1999 Vita Nuova Limited +// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com) +// Portions Copyright © 2004,2006 Bruce Ellis +// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net) +// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others +// Portions Copyright © 2009 The Go Authors. All rights reserved. +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in +// all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +// THE SOFTWARE. + +package arm + +import ( + "fmt" + "log" + "math" + + "github.com/google/gops/internal/obj" + "github.com/google/gops/internal/sys" +) + +var progedit_tlsfallback *obj.LSym + +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 obj.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) + } +} + +// 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) +} + +// Prog.mark +const ( + FOLL = 1 << 0 + LABEL = 1 << 1 + LEAF = 1 << 2 +) + +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 { + ctxt.Logf("save suppressed in: %s\n", cursym.Name) + } + + cursym.Text.Mark |= LEAF + } + + if cursym.Text.Mark&LEAF != 0 { + cursym.Set(obj.AttrLeaf, 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, R8 */ + 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 = REG_R8 + 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 isfloatreg(a *obj.Addr) bool { + return a.Type == obj.TYPE_REG && REG_F0 <= a.Reg && a.Reg <= REG_F15 +} + +func softfloat(ctxt *obj.Link, cursym *obj.LSym) { + if obj.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, + ANEGF, + ANEGD: + 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 stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32) *obj.Prog { + // MOVW g_stackguard(g), R1 + p = obj.Appendp(ctxt, p) + + p.As = AMOVW + p.From.Type = obj.TYPE_MEM + p.From.Reg = REGG + p.From.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0 + if ctxt.Cursym.CFunc() { + p.From.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1 + } + p.To.Type = obj.TYPE_REG + p.To.Reg = REG_R1 + + if framesize <= obj.StackSmall { + // small stack: SP < stackguard + // CMP stackguard, SP + p = obj.Appendp(ctxt, p) + + p.As = ACMP + p.From.Type = obj.TYPE_REG + p.From.Reg = REG_R1 + p.Reg = REGSP + } else if framesize <= obj.StackBig { + // large stack: SP-framesize < stackguard-StackSmall + // MOVW $-framesize(SP), R2 + // CMP stackguard, R2 + p = obj.Appendp(ctxt, p) + + p.As = AMOVW + p.From.Type = obj.TYPE_ADDR + p.From.Reg = REGSP + p.From.Offset = int64(-framesize) + p.To.Type = obj.TYPE_REG + p.To.Reg = REG_R2 + + p = obj.Appendp(ctxt, p) + p.As = ACMP + p.From.Type = obj.TYPE_REG + p.From.Reg = REG_R1 + p.Reg = REG_R2 + } else { + // Such a large stack we need to protect against wraparound + // if SP is close to zero. + // SP-stackguard+StackGuard < framesize + (StackGuard-StackSmall) + // The +StackGuard on both sides is required to keep the left side positive: + // SP is allowed to be slightly below stackguard. See stack.h. + // CMP $StackPreempt, R1 + // MOVW.NE $StackGuard(SP), R2 + // SUB.NE R1, R2 + // MOVW.NE $(framesize+(StackGuard-StackSmall)), R3 + // CMP.NE R3, R2 + p = obj.Appendp(ctxt, p) + + p.As = ACMP + p.From.Type = obj.TYPE_CONST + p.From.Offset = int64(uint32(obj.StackPreempt & (1<<32 - 1))) + p.Reg = REG_R1 + + p = obj.Appendp(ctxt, p) + p.As = AMOVW + p.From.Type = obj.TYPE_ADDR + p.From.Reg = REGSP + p.From.Offset = obj.StackGuard + p.To.Type = obj.TYPE_REG + p.To.Reg = REG_R2 + p.Scond = C_SCOND_NE + + p = obj.Appendp(ctxt, p) + p.As = ASUB + p.From.Type = obj.TYPE_REG + p.From.Reg = REG_R1 + p.To.Type = obj.TYPE_REG + p.To.Reg = REG_R2 + p.Scond = C_SCOND_NE + + p = obj.Appendp(ctxt, p) + p.As = AMOVW + p.From.Type = obj.TYPE_ADDR + p.From.Offset = int64(framesize) + (obj.StackGuard - obj.StackSmall) + p.To.Type = obj.TYPE_REG + p.To.Reg = REG_R3 + p.Scond = C_SCOND_NE + + p = obj.Appendp(ctxt, p) + p.As = ACMP + p.From.Type = obj.TYPE_REG + p.From.Reg = REG_R3 + p.Reg = REG_R2 + p.Scond = C_SCOND_NE + } + + // BLS call-to-morestack + bls := obj.Appendp(ctxt, p) + bls.As = ABLS + bls.To.Type = obj.TYPE_BRANCH + + var last *obj.Prog + for last = ctxt.Cursym.Text; last.Link != nil; last = last.Link { + } + + // Now we are at the end of the function, but logically + // we are still in function prologue. We need to fix the + // SP data and PCDATA. + spfix := obj.Appendp(ctxt, last) + spfix.As = obj.ANOP + spfix.Spadj = -framesize + + pcdata := obj.Appendp(ctxt, spfix) + pcdata.Lineno = ctxt.Cursym.Text.Lineno + pcdata.Mode = ctxt.Cursym.Text.Mode + pcdata.As = obj.APCDATA + pcdata.From.Type = obj.TYPE_CONST + pcdata.From.Offset = obj.PCDATA_StackMapIndex + pcdata.To.Type = obj.TYPE_CONST + pcdata.To.Offset = -1 // pcdata starts at -1 at function entry + + // MOVW LR, R3 + movw := obj.Appendp(ctxt, pcdata) + movw.As = AMOVW + movw.From.Type = obj.TYPE_REG + movw.From.Reg = REGLINK + movw.To.Type = obj.TYPE_REG + movw.To.Reg = REG_R3 + + bls.Pcond = movw + + // BL runtime.morestack + call := obj.Appendp(ctxt, movw) + call.As = obj.ACALL + call.To.Type = obj.TYPE_BRANCH + morestack := "runtime.morestack" + switch { + case ctxt.Cursym.CFunc(): + morestack = "runtime.morestackc" + case ctxt.Cursym.Text.From3.Offset&obj.NEEDCTXT == 0: + morestack = "runtime.morestack_noctxt" + } + call.To.Sym = obj.Linklookup(ctxt, morestack, 0) + + // B start + b := obj.Appendp(ctxt, call) + b.As = obj.AJMP + b.To.Type = obj.TYPE_BRANCH + b.Pcond = ctxt.Cursym.Text.Link + b.Spadj = +framesize + + return bls +} + +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 relinv(a obj.As) obj.As { + switch a { + case ABEQ: + return ABNE + case ABNE: + return ABEQ + case ABCS: + return ABCC + case ABHS: + return ABLO + case ABCC: + return ABCS + case ABLO: + return ABHS + case ABMI: + return ABPL + case ABPL: + return ABMI + case ABVS: + return ABVC + case ABVC: + return ABVS + case ABHI: + return ABLS + case ABLS: + return ABHI + case ABGE: + return ABLT + case ABLT: + return ABGE + case ABGT: + return ABLE + case ABLE: + return ABGT + } + + log.Fatalf("unknown relation: %s", Anames[a]) + return 0 +} + +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 +} + +var unaryDst = map[obj.As]bool{ + ASWI: true, + AWORD: true, +} + +var Linkarm = obj.LinkArch{ + Arch: sys.ArchARM, + Preprocess: preprocess, + Assemble: span5, + Follow: follow, + Progedit: progedit, + UnaryDst: unaryDst, +} |