diff options
Diffstat (limited to 'src/cmd/internal/obj/arm/obj5.go')
| -rw-r--r-- | src/cmd/internal/obj/arm/obj5.go | 839 |
1 files changed, 839 insertions, 0 deletions
diff --git a/src/cmd/internal/obj/arm/obj5.go b/src/cmd/internal/obj/arm/obj5.go new file mode 100644 index 0000000..def4f52 --- /dev/null +++ b/src/cmd/internal/obj/arm/obj5.go @@ -0,0 +1,839 @@ +// 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, <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 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+<off>, Rx becomes MOVW sym@GOT, Rx; ADD <off>, 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, +} |