// Derived from Inferno utils/5c/swt.c // https://bitbucket.org/inferno-os/inferno-os/src/master/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 ( "cmd/internal/obj" "cmd/internal/objabi" "cmd/internal/sys" "internal/abi" "internal/buildcfg" "log" ) var progedit_tlsfallback *obj.LSym func progedit(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) { p.From.Class = 0 p.To.Class = 0 c := ctxt5{ctxt: ctxt, newprog: newprog} // 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, , 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 buildcfg.GOARM.Version < 7 { // Replace it with BL runtime.read_tls_fallback(SB) for ARM CPUs that lack the tls extension. if progedit_tlsfallback == nil { progedit_tlsfallback = ctxt.Lookup("runtime.read_tls_fallback") } // 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(p, newprog) p.As = ABL p.To.Type = obj.TYPE_BRANCH p.To.Sym = progedit_tlsfallback p.To.Offset = 0 // MOVW R11, LR p = obj.Appendp(p, newprog) 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 && c.chipfloat5(p.From.Val.(float64)) < 0 && (c.chipzero5(p.From.Val.(float64)) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) { f32 := float32(p.From.Val.(float64)) p.From.Type = obj.TYPE_MEM p.From.Sym = ctxt.Float32Sym(f32) p.From.Name = obj.NAME_EXTERN p.From.Offset = 0 } case AMOVD: if p.From.Type == obj.TYPE_FCONST && c.chipfloat5(p.From.Val.(float64)) < 0 && (c.chipzero5(p.From.Val.(float64)) < 0 || p.Scond&C_SCOND != C_SCOND_NONE) { p.From.Type = obj.TYPE_MEM p.From.Sym = ctxt.Float64Sym(p.From.Val.(float64)) p.From.Name = obj.NAME_EXTERN p.From.Offset = 0 } } if ctxt.Flag_dynlink { c.rewriteToUseGot(p) } } // Rewrite p, if necessary, to access global data via the global offset table. func (c *ctxt5) rewriteToUseGot(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 = c.ctxt.Lookup("runtime.duffzero") } else { sym = c.ctxt.Lookup("runtime.duffcopy") } 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(p, c.newprog) 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(p1, c.newprog) 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+, Rx becomes MOVW sym@GOT, Rx; ADD , Rx if p.As != AMOVW { c.ctxt.Diag("do not know how to handle TYPE_ADDR in %v with -dynlink", p) } if p.To.Type != obj.TYPE_REG { c.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(p, c.newprog) 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.GetFrom3() != nil && p.GetFrom3().Name == obj.NAME_EXTERN { c.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() { c.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 == objabi.STLSBSS { return } if source.Type != obj.TYPE_MEM { c.ctxt.Diag("don't know how to handle %v with -dynlink", p) } p1 := obj.Appendp(p, c.newprog) p2 := obj.Appendp(p1, c.newprog) 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, newprog obj.ProgAlloc) { autosize := int32(0) if cursym.Func().Text == nil || cursym.Func().Text.Link == nil { return } c := ctxt5{ctxt: ctxt, cursym: cursym, newprog: newprog} p := c.cursym.Func().Text autoffset := int32(p.To.Offset) if autoffset == -4 { // Historical way to mark NOFRAME. p.From.Sym.Set(obj.AttrNoFrame, true) autoffset = 0 } if autoffset < 0 || autoffset%4 != 0 { c.ctxt.Diag("frame size %d not 0 or a positive multiple of 4", autoffset) } if p.From.Sym.NoFrame() { if autoffset != 0 { c.ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", autoffset) } } cursym.Func().Locals = autoffset cursym.Func().Args = p.To.Val.(int32) /* * find leaf subroutines */ for p := cursym.Func().Text; p != nil; p = p.Link { switch p.As { case obj.ATEXT: p.Mark |= LEAF case ADIV, ADIVU, AMOD, AMODU: cursym.Func().Text.Mark &^= LEAF case ABL, ABX, obj.ADUFFZERO, obj.ADUFFCOPY: cursym.Func().Text.Mark &^= LEAF } } var q2 *obj.Prog for p := cursym.Func().Text; p != nil; p = p.Link { o := p.As switch o { case obj.ATEXT: autosize = autoffset if p.Mark&LEAF != 0 && autosize == 0 { // A leaf function with no locals has no frame. p.From.Sym.Set(obj.AttrNoFrame, true) } if !p.From.Sym.NoFrame() { // If there is a stack frame at all, it includes // space to save the LR. autosize += 4 } if autosize == 0 && cursym.Func().Text.Mark&LEAF == 0 { // A very few functions that do not return to their caller // are not identified as leaves but still have no frame. if ctxt.Debugvlog { ctxt.Logf("save suppressed in: %s\n", cursym.Name) } cursym.Func().Text.Mark |= LEAF } // FP offsets need an updated p.To.Offset. p.To.Offset = int64(autosize) - 4 if cursym.Func().Text.Mark&LEAF != 0 { cursym.Set(obj.AttrLeaf, true) if p.From.Sym.NoFrame() { break } } if !p.From.Sym.NoSplit() { p = c.stacksplit(p, autosize) // emit split check } // MOVW.W R14,$-autosize(SP) p = obj.Appendp(p, c.newprog) 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.Func().Text.From.Sym.Wrapper() { // if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame // // MOVW g_panic(g), R1 // CMP $0, R1 // B.NE checkargp // end: // NOP // ... function ... // checkargp: // 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) // B end // // 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(p, newprog) 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(p, newprog) p.As = ACMP p.From.Type = obj.TYPE_CONST p.From.Offset = 0 p.Reg = REG_R1 // B.NE checkargp bne := obj.Appendp(p, newprog) bne.As = ABNE bne.To.Type = obj.TYPE_BRANCH // end: NOP end := obj.Appendp(bne, newprog) end.As = obj.ANOP // find end of function var last *obj.Prog for last = end; last.Link != nil; last = last.Link { } // MOVW panic_argp(R1), R2 mov := obj.Appendp(last, newprog) mov.As = AMOVW mov.From.Type = obj.TYPE_MEM mov.From.Reg = REG_R1 mov.From.Offset = 0 // Panic.argp mov.To.Type = obj.TYPE_REG mov.To.Reg = REG_R2 // B.NE branch target is MOVW above bne.To.SetTarget(mov) // ADD $(autosize+4), R13, R3 p = obj.Appendp(mov, newprog) 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 // CMP R2, R3 p = obj.Appendp(p, newprog) p.As = ACMP p.From.Type = obj.TYPE_REG p.From.Reg = REG_R2 p.Reg = REG_R3 // B.NE end p = obj.Appendp(p, newprog) p.As = ABNE p.To.Type = obj.TYPE_BRANCH p.To.SetTarget(end) // ADD $4, R13, R4 p = obj.Appendp(p, newprog) 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 // MOVW R4, panic_argp(R1) p = obj.Appendp(p, newprog) 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 // B end p = obj.Appendp(p, newprog) p.As = AB p.To.Type = obj.TYPE_BRANCH p.To.SetTarget(end) // reset for subsequent passes p = end } case obj.ARET: nocache(p) if cursym.Func().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(p, newprog) q2.As = AB q2.To.Type = obj.TYPE_BRANCH q2.To.Sym = p.To.Sym p.To.Sym = nil p.To.Name = obj.NAME_NONE p = q2 } case AADD: if p.From.Type == obj.TYPE_CONST && p.From.Reg == 0 && p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP { p.Spadj = int32(-p.From.Offset) } case ASUB: if p.From.Type == obj.TYPE_CONST && p.From.Reg == 0 && p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP { p.Spadj = int32(p.From.Offset) } case ADIV, ADIVU, AMOD, AMODU: if cursym.Func().Text.From.Sym.NoSplit() { ctxt.Diag("cannot divide in NOSPLIT function") } const debugdivmod = false if debugdivmod { break } if p.From.Type != obj.TYPE_REG { break } if p.To.Type != obj.TYPE_REG { break } // Make copy because we overwrite p below. q1 := *p if q1.Reg == REGTMP || q1.Reg == 0 && q1.To.Reg == REGTMP { ctxt.Diag("div already using REGTMP: %v", p) } /* MOV m(g),REGTMP */ p.As = AMOVW p.Pos = q1.Pos p.From.Type = obj.TYPE_MEM p.From.Reg = REGG p.From.Offset = 6 * 4 // offset of g.m p.Reg = 0 p.To.Type = obj.TYPE_REG p.To.Reg = REGTMP /* MOV a,m_divmod(REGTMP) */ p = obj.Appendp(p, newprog) p.As = AMOVW p.Pos = q1.Pos p.From.Type = obj.TYPE_REG p.From.Reg = q1.From.Reg p.To.Type = obj.TYPE_MEM p.To.Reg = REGTMP p.To.Offset = 8 * 4 // offset of m.divmod /* MOV b, R8 */ p = obj.Appendp(p, newprog) p.As = AMOVW p.Pos = q1.Pos p.From.Type = obj.TYPE_REG p.From.Reg = q1.Reg if q1.Reg == 0 { p.From.Reg = q1.To.Reg } p.To.Type = obj.TYPE_REG p.To.Reg = REG_R8 p.To.Offset = 0 /* CALL appropriate */ p = obj.Appendp(p, newprog) p.As = ABL p.Pos = q1.Pos p.To.Type = obj.TYPE_BRANCH switch o { case ADIV: p.To.Sym = symdiv case ADIVU: p.To.Sym = symdivu case AMOD: p.To.Sym = symmod case AMODU: p.To.Sym = symmodu } /* MOV REGTMP, b */ p = obj.Appendp(p, newprog) p.As = AMOVW p.Pos = q1.Pos p.From.Type = obj.TYPE_REG p.From.Reg = REGTMP p.From.Offset = 0 p.To.Type = obj.TYPE_REG p.To.Reg = q1.To.Reg case AMOVW: if (p.Scond&C_WBIT != 0) && p.To.Type == obj.TYPE_MEM && p.To.Reg == REGSP { p.Spadj = int32(-p.To.Offset) } if (p.Scond&C_PBIT != 0) && p.From.Type == obj.TYPE_MEM && p.From.Reg == REGSP && p.To.Reg != REGPC { p.Spadj = int32(-p.From.Offset) } if p.From.Type == obj.TYPE_ADDR && p.From.Reg == REGSP && p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP { p.Spadj = int32(-p.From.Offset) } case obj.AGETCALLERPC: if cursym.Leaf() { /* MOVW LR, Rd */ p.As = AMOVW p.From.Type = obj.TYPE_REG p.From.Reg = REGLINK } else { /* MOVW (RSP), Rd */ p.As = AMOVW p.From.Type = obj.TYPE_MEM p.From.Reg = REGSP } } if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.Spadj == 0 { f := c.cursym.Func() if f.FuncFlag&abi.FuncFlagSPWrite == 0 { c.cursym.Func().FuncFlag |= abi.FuncFlagSPWrite if ctxt.Debugvlog || !ctxt.IsAsm { ctxt.Logf("auto-SPWRITE: %s %v\n", c.cursym.Name, p) if !ctxt.IsAsm { ctxt.Diag("invalid auto-SPWRITE in non-assembly") ctxt.DiagFlush() log.Fatalf("bad SPWRITE") } } } } } } func (c *ctxt5) stacksplit(p *obj.Prog, framesize int32) *obj.Prog { if c.ctxt.Flag_maymorestack != "" { // Save LR and make room for REGCTXT. const frameSize = 8 // MOVW.W R14,$-8(SP) p = obj.Appendp(p, c.newprog) 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 = -frameSize p.To.Reg = REGSP p.Spadj = frameSize // MOVW REGCTXT, 4(SP) p = obj.Appendp(p, c.newprog) p.As = AMOVW p.From.Type = obj.TYPE_REG p.From.Reg = REGCTXT p.To.Type = obj.TYPE_MEM p.To.Offset = 4 p.To.Reg = REGSP // CALL maymorestack p = obj.Appendp(p, c.newprog) p.As = obj.ACALL p.To.Type = obj.TYPE_BRANCH // See ../x86/obj6.go p.To.Sym = c.ctxt.LookupABI(c.ctxt.Flag_maymorestack, c.cursym.ABI()) // Restore REGCTXT and LR. // MOVW 4(SP), REGCTXT p = obj.Appendp(p, c.newprog) p.As = AMOVW p.From.Type = obj.TYPE_MEM p.From.Offset = 4 p.From.Reg = REGSP p.To.Type = obj.TYPE_REG p.To.Reg = REGCTXT // MOVW.P 8(SP), R14 p.As = AMOVW p.Scond |= C_PBIT p.From.Type = obj.TYPE_MEM p.From.Offset = frameSize p.From.Reg = REGSP p.To.Type = obj.TYPE_REG p.To.Reg = REGLINK p.Spadj = -frameSize } // Jump back to here after morestack returns. startPred := p // MOVW g_stackguard(g), R1 p = obj.Appendp(p, c.newprog) p.As = AMOVW p.From.Type = obj.TYPE_MEM p.From.Reg = REGG p.From.Offset = 2 * int64(c.ctxt.Arch.PtrSize) // G.stackguard0 if c.cursym.CFunc() { p.From.Offset = 3 * int64(c.ctxt.Arch.PtrSize) // G.stackguard1 } p.To.Type = obj.TYPE_REG p.To.Reg = REG_R1 // Mark the stack bound check and morestack call async nonpreemptible. // If we get preempted here, when resumed the preemption request is // cleared, but we'll still call morestack, which will double the stack // unnecessarily. See issue #35470. p = c.ctxt.StartUnsafePoint(p, c.newprog) if framesize <= abi.StackSmall { // small stack: SP < stackguard // CMP stackguard, SP p = obj.Appendp(p, c.newprog) p.As = ACMP p.From.Type = obj.TYPE_REG p.From.Reg = REG_R1 p.Reg = REGSP } else if framesize <= abi.StackBig { // large stack: SP-framesize < stackguard-StackSmall // MOVW $-(framesize-StackSmall)(SP), R2 // CMP stackguard, R2 p = obj.Appendp(p, c.newprog) p.As = AMOVW p.From.Type = obj.TYPE_ADDR p.From.Reg = REGSP p.From.Offset = -(int64(framesize) - abi.StackSmall) p.To.Type = obj.TYPE_REG p.To.Reg = REG_R2 p = obj.Appendp(p, c.newprog) p.As = ACMP p.From.Type = obj.TYPE_REG p.From.Reg = REG_R1 p.Reg = REG_R2 } else { // Such a large stack we need to protect against underflow. // The runtime guarantees SP > objabi.StackBig, but // framesize is large enough that SP-framesize may // underflow, causing a direct comparison with the // stack guard to incorrectly succeed. We explicitly // guard against underflow. // // // Try subtracting from SP and check for underflow. // // If this underflows, it sets C to 0. // SUB.S $(framesize-StackSmall), SP, R2 // // If C is 1 (unsigned >=), compare with guard. // CMP.HS stackguard, R2 p = obj.Appendp(p, c.newprog) p.As = ASUB p.Scond = C_SBIT p.From.Type = obj.TYPE_CONST p.From.Offset = int64(framesize) - abi.StackSmall p.Reg = REGSP p.To.Type = obj.TYPE_REG p.To.Reg = REG_R2 p = obj.Appendp(p, c.newprog) p.As = ACMP p.Scond = C_SCOND_HS p.From.Type = obj.TYPE_REG p.From.Reg = REG_R1 p.Reg = REG_R2 } // BLS call-to-morestack (C is 0 or Z is 1) bls := obj.Appendp(p, c.newprog) bls.As = ABLS bls.To.Type = obj.TYPE_BRANCH end := c.ctxt.EndUnsafePoint(bls, c.newprog, -1) var last *obj.Prog for last = c.cursym.Func().Text; last.Link != nil; last = last.Link { } // Now we are at the end of the function, but logically // we are still in function prologue. We need to fix the // SP data and PCDATA. spfix := obj.Appendp(last, c.newprog) spfix.As = obj.ANOP spfix.Spadj = -framesize pcdata := c.ctxt.EmitEntryStackMap(c.cursym, spfix, c.newprog) pcdata = c.ctxt.StartUnsafePoint(pcdata, c.newprog) // MOVW LR, R3 movw := obj.Appendp(pcdata, c.newprog) movw.As = AMOVW movw.From.Type = obj.TYPE_REG movw.From.Reg = REGLINK movw.To.Type = obj.TYPE_REG movw.To.Reg = REG_R3 bls.To.SetTarget(movw) // BL runtime.morestack call := obj.Appendp(movw, c.newprog) call.As = obj.ACALL call.To.Type = obj.TYPE_BRANCH morestack := "runtime.morestack" switch { case c.cursym.CFunc(): morestack = "runtime.morestackc" case !c.cursym.Func().Text.From.Sym.NeedCtxt(): morestack = "runtime.morestack_noctxt" } call.To.Sym = c.ctxt.Lookup(morestack) pcdata = c.ctxt.EndUnsafePoint(call, c.newprog, -1) // B start b := obj.Appendp(pcdata, c.newprog) b.As = obj.AJMP b.To.Type = obj.TYPE_BRANCH b.To.SetTarget(startPred.Link) b.Spadj = +framesize return end } var unaryDst = map[obj.As]bool{ ASWI: true, AWORD: true, } var Linkarm = obj.LinkArch{ Arch: sys.ArchARM, Init: buildop, Preprocess: preprocess, Assemble: span5, Progedit: progedit, UnaryDst: unaryDst, DWARFRegisters: ARMDWARFRegisters, }