src/cmd/internal/obj/arm64/obj7.go

   1 // cmd/7l/noop.c, cmd/7l/obj.c, cmd/ld/pass.c from Vita Nuova.
   2 // https://code.google.com/p/ken-cc/source/browse/
   3 //
   4 //      Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
   5 //      Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
   6 //      Portions Copyright © 1997-1999 Vita Nuova Limited
   7 //      Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
   8 //      Portions Copyright © 2004,2006 Bruce Ellis
   9 //      Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
  10 //      Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
  11 //      Portions Copyright © 2009 The Go Authors. All rights reserved.
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining a copy
  14 // of this software and associated documentation files (the "Software"), to deal
  15 // in the Software without restriction, including without limitation the rights
  16 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  17 // copies of the Software, and to permit persons to whom the Software is
  18 // furnished to do so, subject to the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be included in
  21 // all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  24 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  25 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  26 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  27 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  28 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  29 // THE SOFTWARE.
  30
  31 package arm64
  32
  33 import (
  34         "cmd/internal/obj"
  35         "cmd/internal/objabi"
  36         "cmd/internal/src"
  37         "cmd/internal/sys"
  38         "internal/buildcfg"
  39         "log"
  40         "math"
  41 )
  42
  43 var complements = []obj.As{
  44         AADD:  ASUB,
  45         AADDW: ASUBW,
  46         ASUB:  AADD,
  47         ASUBW: AADDW,
  48         ACMP:  ACMN,
  49         ACMPW: ACMNW,
  50         ACMN:  ACMP,
  51         ACMNW: ACMPW,
  52 }
  53
  54 // zrReplace is the set of instructions for which $0 in the From operand
  55 // should be replaced with REGZERO.
  56 var zrReplace = map[obj.As]bool{
  57         AMOVD:  true,
  58         AMOVW:  true,
  59         AMOVWU: true,
  60         AMOVH:  true,
  61         AMOVHU: true,
  62         AMOVB:  true,
  63         AMOVBU: true,
  64         ASBC:   true,
  65         ASBCW:  true,
  66         ASBCS:  true,
  67         ASBCSW: true,
  68         AADC:   true,
  69         AADCW:  true,
  70         AADCS:  true,
  71         AADCSW: true,
  72 }
  73
  74 func (c *ctxt7) stacksplit(p *obj.Prog, framesize int32) *obj.Prog {
  75         if c.ctxt.Flag_maymorestack != "" {
  76                 p = c.cursym.Func().SpillRegisterArgs(p, c.newprog)
  77
  78                 // Save LR and make room for FP, REGCTXT. Leave room
  79                 // for caller's saved FP.
  80                 const frameSize = 32
  81                 p = obj.Appendp(p, c.newprog)
  82                 p.As = AMOVD
  83                 p.From.Type = obj.TYPE_REG
  84                 p.From.Reg = REGLINK
  85                 p.To.Type = obj.TYPE_MEM
  86                 p.Scond = C_XPRE
  87                 p.To.Offset = -frameSize
  88                 p.To.Reg = REGSP
  89                 p.Spadj = frameSize
  90
  91                 // Save FP.
  92                 p = obj.Appendp(p, c.newprog)
  93                 p.As = AMOVD
  94                 p.From.Type = obj.TYPE_REG
  95                 p.From.Reg = REGFP
  96                 p.To.Type = obj.TYPE_MEM
  97                 p.To.Reg = REGSP
  98                 p.To.Offset = -8
  99
 100                 p = obj.Appendp(p, c.newprog)
 101                 p.As = ASUB
 102                 p.From.Type = obj.TYPE_CONST
 103                 p.From.Offset = 8
 104                 p.Reg = REGSP
 105                 p.To.Type = obj.TYPE_REG
 106                 p.To.Reg = REGFP
 107
 108                 // Save REGCTXT (for simplicity we do this whether or
 109                 // not we need it.)
 110                 p = obj.Appendp(p, c.newprog)
 111                 p.As = AMOVD
 112                 p.From.Type = obj.TYPE_REG
 113                 p.From.Reg = REGCTXT
 114                 p.To.Type = obj.TYPE_MEM
 115                 p.To.Reg = REGSP
 116                 p.To.Offset = 8
 117
 118                 // BL maymorestack
 119                 p = obj.Appendp(p, c.newprog)
 120                 p.As = ABL
 121                 p.To.Type = obj.TYPE_BRANCH
 122                 // See ../x86/obj6.go
 123                 p.To.Sym = c.ctxt.LookupABI(c.ctxt.Flag_maymorestack, c.cursym.ABI())
 124
 125                 // Restore REGCTXT.
 126                 p = obj.Appendp(p, c.newprog)
 127                 p.As = AMOVD
 128                 p.From.Type = obj.TYPE_MEM
 129                 p.From.Reg = REGSP
 130                 p.From.Offset = 8
 131                 p.To.Type = obj.TYPE_REG
 132                 p.To.Reg = REGCTXT
 133
 134                 // Restore FP.
 135                 p = obj.Appendp(p, c.newprog)
 136                 p.As = AMOVD
 137                 p.From.Type = obj.TYPE_MEM
 138                 p.From.Reg = REGSP
 139                 p.From.Offset = -8
 140                 p.To.Type = obj.TYPE_REG
 141                 p.To.Reg = REGFP
 142
 143                 // Restore LR and SP.
 144                 p = obj.Appendp(p, c.newprog)
 145                 p.As = AMOVD
 146                 p.From.Type = obj.TYPE_MEM
 147                 p.Scond = C_XPOST
 148                 p.From.Offset = frameSize
 149                 p.From.Reg = REGSP
 150                 p.To.Type = obj.TYPE_REG
 151                 p.To.Reg = REGLINK
 152                 p.Spadj = -frameSize
 153
 154                 p = c.cursym.Func().UnspillRegisterArgs(p, c.newprog)
 155         }
 156
 157         // Jump back to here after morestack returns.
 158         startPred := p
 159
 160         // MOV  g_stackguard(g), RT1
 161         p = obj.Appendp(p, c.newprog)
 162
 163         p.As = AMOVD
 164         p.From.Type = obj.TYPE_MEM
 165         p.From.Reg = REGG
 166         p.From.Offset = 2 * int64(c.ctxt.Arch.PtrSize) // G.stackguard0
 167         if c.cursym.CFunc() {
 168                 p.From.Offset = 3 * int64(c.ctxt.Arch.PtrSize) // G.stackguard1
 169         }
 170         p.To.Type = obj.TYPE_REG
 171         p.To.Reg = REGRT1
 172
 173         // Mark the stack bound check and morestack call async nonpreemptible.
 174         // If we get preempted here, when resumed the preemption request is
 175         // cleared, but we'll still call morestack, which will double the stack
 176         // unnecessarily. See issue #35470.
 177         p = c.ctxt.StartUnsafePoint(p, c.newprog)
 178
 179         q := (*obj.Prog)(nil)
 180         if framesize <= objabi.StackSmall {
 181                 // small stack: SP < stackguard
 182                 //      CMP     stackguard, SP
 183
 184                 p = obj.Appendp(p, c.newprog)
 185                 p.As = ACMP
 186                 p.From.Type = obj.TYPE_REG
 187                 p.From.Reg = REGRT1
 188                 p.Reg = REGSP
 189         } else if framesize <= objabi.StackBig {
 190                 // large stack: SP-framesize < stackguard-StackSmall
 191                 //      SUB     $(framesize-StackSmall), SP, RT2
 192                 //      CMP     stackguard, RT2
 193                 p = obj.Appendp(p, c.newprog)
 194
 195                 p.As = ASUB
 196                 p.From.Type = obj.TYPE_CONST
 197                 p.From.Offset = int64(framesize) - objabi.StackSmall
 198                 p.Reg = REGSP
 199                 p.To.Type = obj.TYPE_REG
 200                 p.To.Reg = REGRT2
 201
 202                 p = obj.Appendp(p, c.newprog)
 203                 p.As = ACMP
 204                 p.From.Type = obj.TYPE_REG
 205                 p.From.Reg = REGRT1
 206                 p.Reg = REGRT2
 207         } else {
 208                 // Such a large stack we need to protect against underflow.
 209                 // The runtime guarantees SP > objabi.StackBig, but
 210                 // framesize is large enough that SP-framesize may
 211                 // underflow, causing a direct comparison with the
 212                 // stack guard to incorrectly succeed. We explicitly
 213                 // guard against underflow.
 214                 //
 215                 //      SUBS    $(framesize-StackSmall), SP, RT2
 216                 //      // On underflow, jump to morestack
 217                 //      BLO     label_of_call_to_morestack
 218                 //      CMP     stackguard, RT2
 219
 220                 p = obj.Appendp(p, c.newprog)
 221                 p.As = ASUBS
 222                 p.From.Type = obj.TYPE_CONST
 223                 p.From.Offset = int64(framesize) - objabi.StackSmall
 224                 p.Reg = REGSP
 225                 p.To.Type = obj.TYPE_REG
 226                 p.To.Reg = REGRT2
 227
 228                 p = obj.Appendp(p, c.newprog)
 229                 q = p
 230                 p.As = ABLO
 231                 p.To.Type = obj.TYPE_BRANCH
 232
 233                 p = obj.Appendp(p, c.newprog)
 234                 p.As = ACMP
 235                 p.From.Type = obj.TYPE_REG
 236                 p.From.Reg = REGRT1
 237                 p.Reg = REGRT2
 238         }
 239
 240         // BLS  do-morestack
 241         bls := obj.Appendp(p, c.newprog)
 242         bls.As = ABLS
 243         bls.To.Type = obj.TYPE_BRANCH
 244
 245         end := c.ctxt.EndUnsafePoint(bls, c.newprog, -1)
 246
 247         var last *obj.Prog
 248         for last = c.cursym.Func().Text; last.Link != nil; last = last.Link {
 249         }
 250
 251         // Now we are at the end of the function, but logically
 252         // we are still in function prologue. We need to fix the
 253         // SP data and PCDATA.
 254         spfix := obj.Appendp(last, c.newprog)
 255         spfix.As = obj.ANOP
 256         spfix.Spadj = -framesize
 257
 258         pcdata := c.ctxt.EmitEntryStackMap(c.cursym, spfix, c.newprog)
 259         pcdata = c.ctxt.StartUnsafePoint(pcdata, c.newprog)
 260
 261         if q != nil {
 262                 q.To.SetTarget(pcdata)
 263         }
 264         bls.To.SetTarget(pcdata)
 265
 266         spill := c.cursym.Func().SpillRegisterArgs(pcdata, c.newprog)
 267
 268         // MOV  LR, R3
 269         movlr := obj.Appendp(spill, c.newprog)
 270         movlr.As = AMOVD
 271         movlr.From.Type = obj.TYPE_REG
 272         movlr.From.Reg = REGLINK
 273         movlr.To.Type = obj.TYPE_REG
 274         movlr.To.Reg = REG_R3
 275
 276         debug := movlr
 277         if false {
 278                 debug = obj.Appendp(debug, c.newprog)
 279                 debug.As = AMOVD
 280                 debug.From.Type = obj.TYPE_CONST
 281                 debug.From.Offset = int64(framesize)
 282                 debug.To.Type = obj.TYPE_REG
 283                 debug.To.Reg = REGTMP
 284         }
 285
 286         // BL   runtime.morestack(SB)
 287         call := obj.Appendp(debug, c.newprog)
 288         call.As = ABL
 289         call.To.Type = obj.TYPE_BRANCH
 290         morestack := "runtime.morestack"
 291         switch {
 292         case c.cursym.CFunc():
 293                 morestack = "runtime.morestackc"
 294         case !c.cursym.Func().Text.From.Sym.NeedCtxt():
 295                 morestack = "runtime.morestack_noctxt"
 296         }
 297         call.To.Sym = c.ctxt.Lookup(morestack)
 298
 299         unspill := c.cursym.Func().UnspillRegisterArgs(call, c.newprog)
 300         pcdata = c.ctxt.EndUnsafePoint(unspill, c.newprog, -1)
 301
 302         // B    start
 303         jmp := obj.Appendp(pcdata, c.newprog)
 304         jmp.As = AB
 305         jmp.To.Type = obj.TYPE_BRANCH
 306         jmp.To.SetTarget(startPred.Link)
 307         jmp.Spadj = +framesize
 308
 309         return end
 310 }
 311
 312 func progedit(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) {
 313         c := ctxt7{ctxt: ctxt, newprog: newprog}
 314
 315         p.From.Class = 0
 316         p.To.Class = 0
 317
 318         // Previously we rewrote $0 to ZR, but we have now removed this change.
 319         // In order to be compatible with some previous legal instruction formats,
 320         // reserve the previous conversion for some specific instructions.
 321         if p.From.Type == obj.TYPE_CONST && p.From.Offset == 0 && zrReplace[p.As] {
 322                 p.From.Type = obj.TYPE_REG
 323                 p.From.Reg = REGZERO
 324         }
 325
 326         // Rewrite BR/BL to symbol as TYPE_BRANCH.
 327         switch p.As {
 328         case AB,
 329                 ABL,
 330                 obj.ARET,
 331                 obj.ADUFFZERO,
 332                 obj.ADUFFCOPY:
 333                 if p.To.Sym != nil {
 334                         p.To.Type = obj.TYPE_BRANCH
 335                 }
 336                 break
 337         }
 338
 339         // Rewrite float constants to values stored in memory.
 340         switch p.As {
 341         case AFMOVS:
 342                 if p.From.Type == obj.TYPE_FCONST {
 343                         f64 := p.From.Val.(float64)
 344                         f32 := float32(f64)
 345                         if c.chipfloat7(f64) > 0 {
 346                                 break
 347                         }
 348                         if math.Float32bits(f32) == 0 {
 349                                 p.From.Type = obj.TYPE_REG
 350                                 p.From.Reg = REGZERO
 351                                 break
 352                         }
 353                         p.From.Type = obj.TYPE_MEM
 354                         p.From.Sym = c.ctxt.Float32Sym(f32)
 355                         p.From.Name = obj.NAME_EXTERN
 356                         p.From.Offset = 0
 357                 }
 358
 359         case AFMOVD:
 360                 if p.From.Type == obj.TYPE_FCONST {
 361                         f64 := p.From.Val.(float64)
 362                         if c.chipfloat7(f64) > 0 {
 363                                 break
 364                         }
 365                         if math.Float64bits(f64) == 0 {
 366                                 p.From.Type = obj.TYPE_REG
 367                                 p.From.Reg = REGZERO
 368                                 break
 369                         }
 370                         p.From.Type = obj.TYPE_MEM
 371                         p.From.Sym = c.ctxt.Float64Sym(f64)
 372                         p.From.Name = obj.NAME_EXTERN
 373                         p.From.Offset = 0
 374                 }
 375
 376                 break
 377         }
 378
 379         // Rewrite negative immediates as positive immediates with
 380         // complementary instruction.
 381         switch p.As {
 382         case AADD, ASUB, ACMP, ACMN:
 383                 if p.From.Type == obj.TYPE_CONST && p.From.Offset < 0 && p.From.Offset != -1<<63 {
 384                         p.From.Offset = -p.From.Offset
 385                         p.As = complements[p.As]
 386                 }
 387         case AADDW, ASUBW, ACMPW, ACMNW:
 388                 if p.From.Type == obj.TYPE_CONST && p.From.Offset < 0 && int32(p.From.Offset) != -1<<31 {
 389                         p.From.Offset = -p.From.Offset
 390                         p.As = complements[p.As]
 391                 }
 392         }
 393
 394         if c.ctxt.Flag_dynlink {
 395                 c.rewriteToUseGot(p)
 396         }
 397 }
 398
 399 // Rewrite p, if necessary, to access global data via the global offset table.
 400 func (c *ctxt7) rewriteToUseGot(p *obj.Prog) {
 401         if p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
 402                 //     ADUFFxxx $offset
 403                 // becomes
 404                 //     MOVD runtime.duffxxx@GOT, REGTMP
 405                 //     ADD $offset, REGTMP
 406                 //     CALL REGTMP
 407                 var sym *obj.LSym
 408                 if p.As == obj.ADUFFZERO {
 409                         sym = c.ctxt.LookupABI("runtime.duffzero", obj.ABIInternal)
 410                 } else {
 411                         sym = c.ctxt.LookupABI("runtime.duffcopy", obj.ABIInternal)
 412                 }
 413                 offset := p.To.Offset
 414                 p.As = AMOVD
 415                 p.From.Type = obj.TYPE_MEM
 416                 p.From.Name = obj.NAME_GOTREF
 417                 p.From.Sym = sym
 418                 p.To.Type = obj.TYPE_REG
 419                 p.To.Reg = REGTMP
 420                 p.To.Name = obj.NAME_NONE
 421                 p.To.Offset = 0
 422                 p.To.Sym = nil
 423                 p1 := obj.Appendp(p, c.newprog)
 424                 p1.As = AADD
 425                 p1.From.Type = obj.TYPE_CONST
 426                 p1.From.Offset = offset
 427                 p1.To.Type = obj.TYPE_REG
 428                 p1.To.Reg = REGTMP
 429                 p2 := obj.Appendp(p1, c.newprog)
 430                 p2.As = obj.ACALL
 431                 p2.To.Type = obj.TYPE_REG
 432                 p2.To.Reg = REGTMP
 433         }
 434
 435         // We only care about global data: NAME_EXTERN means a global
 436         // symbol in the Go sense, and p.Sym.Local is true for a few
 437         // internally defined symbols.
 438         if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() {
 439                 // MOVD $sym, Rx becomes MOVD sym@GOT, Rx
 440                 // MOVD $sym+<off>, Rx becomes MOVD sym@GOT, Rx; ADD <off>, Rx
 441                 if p.As != AMOVD {
 442                         c.ctxt.Diag("do not know how to handle TYPE_ADDR in %v with -dynlink", p)
 443                 }
 444                 if p.To.Type != obj.TYPE_REG {
 445                         c.ctxt.Diag("do not know how to handle LEAQ-type insn to non-register in %v with -dynlink", p)
 446                 }
 447                 p.From.Type = obj.TYPE_MEM
 448                 p.From.Name = obj.NAME_GOTREF
 449                 if p.From.Offset != 0 {
 450                         q := obj.Appendp(p, c.newprog)
 451                         q.As = AADD
 452                         q.From.Type = obj.TYPE_CONST
 453                         q.From.Offset = p.From.Offset
 454                         q.To = p.To
 455                         p.From.Offset = 0
 456                 }
 457         }
 458         if p.GetFrom3() != nil && p.GetFrom3().Name == obj.NAME_EXTERN {
 459                 c.ctxt.Diag("don't know how to handle %v with -dynlink", p)
 460         }
 461         var source *obj.Addr
 462         // MOVx sym, Ry becomes MOVD sym@GOT, REGTMP; MOVx (REGTMP), Ry
 463         // MOVx Ry, sym becomes MOVD sym@GOT, REGTMP; MOVD Ry, (REGTMP)
 464         // An addition may be inserted between the two MOVs if there is an offset.
 465         if p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() {
 466                 if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local() {
 467                         c.ctxt.Diag("cannot handle NAME_EXTERN on both sides in %v with -dynlink", p)
 468                 }
 469                 source = &p.From
 470         } else if p.To.Name == obj.NAME_EXTERN && !p.To.Sym.Local() {
 471                 source = &p.To
 472         } else {
 473                 return
 474         }
 475         if p.As == obj.ATEXT || p.As == obj.AFUNCDATA || p.As == obj.ACALL || p.As == obj.ARET || p.As == obj.AJMP {
 476                 return
 477         }
 478         if source.Sym.Type == objabi.STLSBSS {
 479                 return
 480         }
 481         if source.Type != obj.TYPE_MEM {
 482                 c.ctxt.Diag("don't know how to handle %v with -dynlink", p)
 483         }
 484         p1 := obj.Appendp(p, c.newprog)
 485         p2 := obj.Appendp(p1, c.newprog)
 486         p1.As = AMOVD
 487         p1.From.Type = obj.TYPE_MEM
 488         p1.From.Sym = source.Sym
 489         p1.From.Name = obj.NAME_GOTREF
 490         p1.To.Type = obj.TYPE_REG
 491         p1.To.Reg = REGTMP
 492
 493         p2.As = p.As
 494         p2.From = p.From
 495         p2.To = p.To
 496         if p.From.Name == obj.NAME_EXTERN {
 497                 p2.From.Reg = REGTMP
 498                 p2.From.Name = obj.NAME_NONE
 499                 p2.From.Sym = nil
 500         } else if p.To.Name == obj.NAME_EXTERN {
 501                 p2.To.Reg = REGTMP
 502                 p2.To.Name = obj.NAME_NONE
 503                 p2.To.Sym = nil
 504         } else {
 505                 return
 506         }
 507         obj.Nopout(p)
 508 }
 509
 510 func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 511         if cursym.Func().Text == nil || cursym.Func().Text.Link == nil {
 512                 return
 513         }
 514
 515         c := ctxt7{ctxt: ctxt, newprog: newprog, cursym: cursym}
 516
 517         p := c.cursym.Func().Text
 518         textstksiz := p.To.Offset
 519         if textstksiz == -8 {
 520                 // Historical way to mark NOFRAME.
 521                 p.From.Sym.Set(obj.AttrNoFrame, true)
 522                 textstksiz = 0
 523         }
 524         if textstksiz < 0 {
 525                 c.ctxt.Diag("negative frame size %d - did you mean NOFRAME?", textstksiz)
 526         }
 527         if p.From.Sym.NoFrame() {
 528                 if textstksiz != 0 {
 529                         c.ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", textstksiz)
 530                 }
 531         }
 532
 533         c.cursym.Func().Args = p.To.Val.(int32)
 534         c.cursym.Func().Locals = int32(textstksiz)
 535
 536         /*
 537          * find leaf subroutines
 538          */
 539         for p := c.cursym.Func().Text; p != nil; p = p.Link {
 540                 switch p.As {
 541                 case obj.ATEXT:
 542                         p.Mark |= LEAF
 543
 544                 case ABL,
 545                         obj.ADUFFZERO,
 546                         obj.ADUFFCOPY:
 547                         c.cursym.Func().Text.Mark &^= LEAF
 548                 }
 549         }
 550
 551         var q *obj.Prog
 552         var q1 *obj.Prog
 553         var retjmp *obj.LSym
 554         for p := c.cursym.Func().Text; p != nil; p = p.Link {
 555                 o := p.As
 556                 switch o {
 557                 case obj.ATEXT:
 558                         c.cursym.Func().Text = p
 559                         c.autosize = int32(textstksiz)
 560
 561                         if p.Mark&LEAF != 0 && c.autosize == 0 {
 562                                 // A leaf function with no locals has no frame.
 563                                 p.From.Sym.Set(obj.AttrNoFrame, true)
 564                         }
 565
 566                         if !p.From.Sym.NoFrame() {
 567                                 // If there is a stack frame at all, it includes
 568                                 // space to save the LR.
 569                                 c.autosize += 8
 570                         }
 571
 572                         if c.autosize != 0 {
 573                                 extrasize := int32(0)
 574                                 if c.autosize%16 == 8 {
 575                                         // Allocate extra 8 bytes on the frame top to save FP
 576                                         extrasize = 8
 577                                 } else if c.autosize&(16-1) == 0 {
 578                                         // Allocate extra 16 bytes to save FP for the old frame whose size is 8 mod 16
 579                                         extrasize = 16
 580                                 } else {
 581                                         c.ctxt.Diag("%v: unaligned frame size %d - must be 16 aligned", p, c.autosize-8)
 582                                 }
 583                                 c.autosize += extrasize
 584                                 c.cursym.Func().Locals += extrasize
 585
 586                                 // low 32 bits for autosize
 587                                 // high 32 bits for extrasize
 588                                 p.To.Offset = int64(c.autosize) | int64(extrasize)<<32
 589                         } else {
 590                                 // NOFRAME
 591                                 p.To.Offset = 0
 592                         }
 593
 594                         if c.autosize == 0 && c.cursym.Func().Text.Mark&LEAF == 0 {
 595                                 if c.ctxt.Debugvlog {
 596                                         c.ctxt.Logf("save suppressed in: %s\n", c.cursym.Func().Text.From.Sym.Name)
 597                                 }
 598                                 c.cursym.Func().Text.Mark |= LEAF
 599                         }
 600
 601                         if cursym.Func().Text.Mark&LEAF != 0 {
 602                                 cursym.Set(obj.AttrLeaf, true)
 603                                 if p.From.Sym.NoFrame() {
 604                                         break
 605                                 }
 606                         }
 607
 608                         if p.Mark&LEAF != 0 && c.autosize < objabi.StackSmall {
 609                                 // A leaf function with a small stack can be marked
 610                                 // NOSPLIT, avoiding a stack check.
 611                                 p.From.Sym.Set(obj.AttrNoSplit, true)
 612                         }
 613
 614                         if !p.From.Sym.NoSplit() {
 615                                 p = c.stacksplit(p, c.autosize) // emit split check
 616                         }
 617
 618                         var prologueEnd *obj.Prog
 619
 620                         aoffset := c.autosize
 621                         if aoffset > 0xf0 {
 622                                 // MOVD.W offset variant range is -0x100 to 0xf8, SP should be 16-byte aligned.
 623                                 // so the maximum aoffset value is 0xf0.
 624                                 aoffset = 0xf0
 625                         }
 626
 627                         // Frame is non-empty. Make sure to save link register, even if
 628                         // it is a leaf function, so that traceback works.
 629                         q = p
 630                         if c.autosize > aoffset {
 631                                 // Frame size is too large for a MOVD.W instruction. Store the frame pointer
 632                                 // register and link register before decrementing SP, so if a signal comes
 633                                 // during the execution of the function prologue, the traceback code will
 634                                 // not see a half-updated stack frame.
 635
 636                                 // SUB $autosize, RSP, R20
 637                                 q1 = obj.Appendp(q, c.newprog)
 638                                 q1.Pos = p.Pos
 639                                 q1.As = ASUB
 640                                 q1.From.Type = obj.TYPE_CONST
 641                                 q1.From.Offset = int64(c.autosize)
 642                                 q1.Reg = REGSP
 643                                 q1.To.Type = obj.TYPE_REG
 644                                 q1.To.Reg = REG_R20
 645
 646                                 prologueEnd = q1
 647
 648                                 // STP (R29, R30), -8(R20)
 649                                 q1 = obj.Appendp(q1, c.newprog)
 650                                 q1.Pos = p.Pos
 651                                 q1.As = ASTP
 652                                 q1.From.Type = obj.TYPE_REGREG
 653                                 q1.From.Reg = REGFP
 654                                 q1.From.Offset = REGLINK
 655                                 q1.To.Type = obj.TYPE_MEM
 656                                 q1.To.Reg = REG_R20
 657                                 q1.To.Offset = -8
 658
 659                                 // This is not async preemptible, as if we open a frame
 660                                 // at the current SP, it will clobber the saved LR.
 661                                 q1 = c.ctxt.StartUnsafePoint(q1, c.newprog)
 662
 663                                 // MOVD R20, RSP
 664                                 q1 = obj.Appendp(q1, c.newprog)
 665                                 q1.Pos = p.Pos
 666                                 q1.As = AMOVD
 667                                 q1.From.Type = obj.TYPE_REG
 668                                 q1.From.Reg = REG_R20
 669                                 q1.To.Type = obj.TYPE_REG
 670                                 q1.To.Reg = REGSP
 671                                 q1.Spadj = c.autosize
 672
 673                                 q1 = c.ctxt.EndUnsafePoint(q1, c.newprog, -1)
 674
 675                                 if buildcfg.GOOS == "ios" {
 676                                         // iOS does not support SA_ONSTACK. We will run the signal handler
 677                                         // on the G stack. If we write below SP, it may be clobbered by
 678                                         // the signal handler. So we save FP and LR after decrementing SP.
 679                                         // STP (R29, R30), -8(RSP)
 680                                         q1 = obj.Appendp(q1, c.newprog)
 681                                         q1.Pos = p.Pos
 682                                         q1.As = ASTP
 683                                         q1.From.Type = obj.TYPE_REGREG
 684                                         q1.From.Reg = REGFP
 685                                         q1.From.Offset = REGLINK
 686                                         q1.To.Type = obj.TYPE_MEM
 687                                         q1.To.Reg = REGSP
 688                                         q1.To.Offset = -8
 689                                 }
 690                         } else {
 691                                 // small frame, update SP and save LR in a single MOVD.W instruction.
 692                                 // So if a signal comes during the execution of the function prologue,
 693                                 // the traceback code will not see a half-updated stack frame.
 694                                 // Also, on Linux, in a cgo binary we may get a SIGSETXID signal
 695                                 // early on before the signal stack is set, as glibc doesn't allow
 696                                 // us to block SIGSETXID. So it is important that we don't write below
 697                                 // the SP until the signal stack is set.
 698                                 // Luckily, all the functions from thread entry to setting the signal
 699                                 // stack have small frames.
 700                                 q1 = obj.Appendp(q, c.newprog)
 701                                 q1.As = AMOVD
 702                                 q1.Pos = p.Pos
 703                                 q1.From.Type = obj.TYPE_REG
 704                                 q1.From.Reg = REGLINK
 705                                 q1.To.Type = obj.TYPE_MEM
 706                                 q1.Scond = C_XPRE
 707                                 q1.To.Offset = int64(-aoffset)
 708                                 q1.To.Reg = REGSP
 709                                 q1.Spadj = aoffset
 710
 711                                 prologueEnd = q1
 712
 713                                 // Frame pointer.
 714                                 q1 = obj.Appendp(q1, c.newprog)
 715                                 q1.Pos = p.Pos
 716                                 q1.As = AMOVD
 717                                 q1.From.Type = obj.TYPE_REG
 718                                 q1.From.Reg = REGFP
 719                                 q1.To.Type = obj.TYPE_MEM
 720                                 q1.To.Reg = REGSP
 721                                 q1.To.Offset = -8
 722                         }
 723
 724                         prologueEnd.Pos = prologueEnd.Pos.WithXlogue(src.PosPrologueEnd)
 725
 726                         q1 = obj.Appendp(q1, c.newprog)
 727                         q1.Pos = p.Pos
 728                         q1.As = ASUB
 729                         q1.From.Type = obj.TYPE_CONST
 730                         q1.From.Offset = 8
 731                         q1.Reg = REGSP
 732                         q1.To.Type = obj.TYPE_REG
 733                         q1.To.Reg = REGFP
 734
 735                         if c.cursym.Func().Text.From.Sym.Wrapper() {
 736                                 // if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
 737                                 //
 738                                 //      MOV  g_panic(g), RT1
 739                                 //      CBNZ checkargp
 740                                 // end:
 741                                 //      NOP
 742                                 // ... function body ...
 743                                 // checkargp:
 744                                 //      MOV  panic_argp(RT1), RT2
 745                                 //      ADD  $(autosize+8), RSP, R20
 746                                 //      CMP  RT2, R20
 747                                 //      BNE  end
 748                                 //      ADD  $8, RSP, R20
 749                                 //      MOVD R20, panic_argp(RT1)
 750                                 //      B    end
 751                                 //
 752                                 // The NOP is needed to give the jumps somewhere to land.
 753                                 // It is a liblink NOP, not an ARM64 NOP: it encodes to 0 instruction bytes.
 754                                 q = q1
 755
 756                                 // MOV g_panic(g), RT1
 757                                 q = obj.Appendp(q, c.newprog)
 758                                 q.As = AMOVD
 759                                 q.From.Type = obj.TYPE_MEM
 760                                 q.From.Reg = REGG
 761                                 q.From.Offset = 4 * int64(c.ctxt.Arch.PtrSize) // G.panic
 762                                 q.To.Type = obj.TYPE_REG
 763                                 q.To.Reg = REGRT1
 764
 765                                 // CBNZ RT1, checkargp
 766                                 cbnz := obj.Appendp(q, c.newprog)
 767                                 cbnz.As = ACBNZ
 768                                 cbnz.From.Type = obj.TYPE_REG
 769                                 cbnz.From.Reg = REGRT1
 770                                 cbnz.To.Type = obj.TYPE_BRANCH
 771
 772                                 // Empty branch target at the top of the function body
 773                                 end := obj.Appendp(cbnz, c.newprog)
 774                                 end.As = obj.ANOP
 775
 776                                 // find the end of the function
 777                                 var last *obj.Prog
 778                                 for last = end; last.Link != nil; last = last.Link {
 779                                 }
 780
 781                                 // MOV panic_argp(RT1), RT2
 782                                 mov := obj.Appendp(last, c.newprog)
 783                                 mov.As = AMOVD
 784                                 mov.From.Type = obj.TYPE_MEM
 785                                 mov.From.Reg = REGRT1
 786                                 mov.From.Offset = 0 // Panic.argp
 787                                 mov.To.Type = obj.TYPE_REG
 788                                 mov.To.Reg = REGRT2
 789
 790                                 // CBNZ branches to the MOV above
 791                                 cbnz.To.SetTarget(mov)
 792
 793                                 // ADD $(autosize+8), SP, R20
 794                                 q = obj.Appendp(mov, c.newprog)
 795                                 q.As = AADD
 796                                 q.From.Type = obj.TYPE_CONST
 797                                 q.From.Offset = int64(c.autosize) + 8
 798                                 q.Reg = REGSP
 799                                 q.To.Type = obj.TYPE_REG
 800                                 q.To.Reg = REG_R20
 801
 802                                 // CMP RT2, R20
 803                                 q = obj.Appendp(q, c.newprog)
 804                                 q.As = ACMP
 805                                 q.From.Type = obj.TYPE_REG
 806                                 q.From.Reg = REGRT2
 807                                 q.Reg = REG_R20
 808
 809                                 // BNE end
 810                                 q = obj.Appendp(q, c.newprog)
 811                                 q.As = ABNE
 812                                 q.To.Type = obj.TYPE_BRANCH
 813                                 q.To.SetTarget(end)
 814
 815                                 // ADD $8, SP, R20
 816                                 q = obj.Appendp(q, c.newprog)
 817                                 q.As = AADD
 818                                 q.From.Type = obj.TYPE_CONST
 819                                 q.From.Offset = 8
 820                                 q.Reg = REGSP
 821                                 q.To.Type = obj.TYPE_REG
 822                                 q.To.Reg = REG_R20
 823
 824                                 // MOV R20, panic_argp(RT1)
 825                                 q = obj.Appendp(q, c.newprog)
 826                                 q.As = AMOVD
 827                                 q.From.Type = obj.TYPE_REG
 828                                 q.From.Reg = REG_R20
 829                                 q.To.Type = obj.TYPE_MEM
 830                                 q.To.Reg = REGRT1
 831                                 q.To.Offset = 0 // Panic.argp
 832
 833                                 // B end
 834                                 q = obj.Appendp(q, c.newprog)
 835                                 q.As = AB
 836                                 q.To.Type = obj.TYPE_BRANCH
 837                                 q.To.SetTarget(end)
 838                         }
 839
 840                 case obj.ARET:
 841                         nocache(p)
 842                         if p.From.Type == obj.TYPE_CONST {
 843                                 c.ctxt.Diag("using BECOME (%v) is not supported!", p)
 844                                 break
 845                         }
 846
 847                         retjmp = p.To.Sym
 848                         p.To = obj.Addr{}
 849                         if c.cursym.Func().Text.Mark&LEAF != 0 {
 850                                 if c.autosize != 0 {
 851                                         p.As = AADD
 852                                         p.From.Type = obj.TYPE_CONST
 853                                         p.From.Offset = int64(c.autosize)
 854                                         p.To.Type = obj.TYPE_REG
 855                                         p.To.Reg = REGSP
 856                                         p.Spadj = -c.autosize
 857
 858                                         // Frame pointer.
 859                                         p = obj.Appendp(p, c.newprog)
 860                                         p.As = ASUB
 861                                         p.From.Type = obj.TYPE_CONST
 862                                         p.From.Offset = 8
 863                                         p.Reg = REGSP
 864                                         p.To.Type = obj.TYPE_REG
 865                                         p.To.Reg = REGFP
 866                                 }
 867                         } else {
 868                                 aoffset := c.autosize
 869                                 // LDP -8(RSP), (R29, R30)
 870                                 p.As = ALDP
 871                                 p.From.Type = obj.TYPE_MEM
 872                                 p.From.Offset = -8
 873                                 p.From.Reg = REGSP
 874                                 p.To.Type = obj.TYPE_REGREG
 875                                 p.To.Reg = REGFP
 876                                 p.To.Offset = REGLINK
 877
 878                                 // ADD $aoffset, RSP, RSP
 879                                 q = newprog()
 880                                 q.As = AADD
 881                                 q.From.Type = obj.TYPE_CONST
 882                                 q.From.Offset = int64(aoffset)
 883                                 q.To.Type = obj.TYPE_REG
 884                                 q.To.Reg = REGSP
 885                                 q.Spadj = -aoffset
 886                                 q.Pos = p.Pos
 887                                 q.Link = p.Link
 888                                 p.Link = q
 889                                 p = q
 890                         }
 891
 892                         // If enabled, this code emits 'MOV PC, R27' before every 'MOV LR, PC',
 893                         // so that if you are debugging a low-level crash where PC and LR are zero,
 894                         // you can look at R27 to see what jumped to the zero.
 895                         // This is useful when bringing up Go on a new system.
 896                         // (There is similar code in ../ppc64/obj9.go:/if.false.)
 897                         const debugRETZERO = false
 898                         if debugRETZERO {
 899                                 if p.As != obj.ARET {
 900                                         q = newprog()
 901                                         q.Pos = p.Pos
 902                                         q.Link = p.Link
 903                                         p.Link = q
 904                                         p = q
 905                                 }
 906                                 p.As = AADR
 907                                 p.From.Type = obj.TYPE_BRANCH
 908                                 p.From.Offset = 0
 909                                 p.To.Type = obj.TYPE_REG
 910                                 p.To.Reg = REGTMP
 911
 912                         }
 913
 914                         if p.As != obj.ARET {
 915                                 q = newprog()
 916                                 q.Pos = p.Pos
 917                                 q.Link = p.Link
 918                                 p.Link = q
 919                                 p = q
 920                         }
 921
 922                         if retjmp != nil { // retjmp
 923                                 p.As = AB
 924                                 p.To.Type = obj.TYPE_BRANCH
 925                                 p.To.Sym = retjmp
 926                                 p.Spadj = +c.autosize
 927                                 break
 928                         }
 929
 930                         p.As = obj.ARET
 931                         p.To.Type = obj.TYPE_MEM
 932                         p.To.Offset = 0
 933                         p.To.Reg = REGLINK
 934                         p.Spadj = +c.autosize
 935
 936                 case AADD, ASUB:
 937                         if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.From.Type == obj.TYPE_CONST {
 938                                 if p.As == AADD {
 939                                         p.Spadj = int32(-p.From.Offset)
 940                                 } else {
 941                                         p.Spadj = int32(+p.From.Offset)
 942                                 }
 943                         }
 944
 945                 case obj.AGETCALLERPC:
 946                         if cursym.Leaf() {
 947                                 /* MOVD LR, Rd */
 948                                 p.As = AMOVD
 949                                 p.From.Type = obj.TYPE_REG
 950                                 p.From.Reg = REGLINK
 951                         } else {
 952                                 /* MOVD (RSP), Rd */
 953                                 p.As = AMOVD
 954                                 p.From.Type = obj.TYPE_MEM
 955                                 p.From.Reg = REGSP
 956                         }
 957
 958                 case obj.ADUFFCOPY:
 959                         //  ADR ret_addr, R27
 960                         //  STP (FP, R27), -24(SP)
 961                         //  SUB 24, SP, FP
 962                         //  DUFFCOPY
 963                         // ret_addr:
 964                         //  SUB 8, SP, FP
 965
 966                         q1 := p
 967                         // copy DUFFCOPY from q1 to q4
 968                         q4 := obj.Appendp(p, c.newprog)
 969                         q4.Pos = p.Pos
 970                         q4.As = obj.ADUFFCOPY
 971                         q4.To = p.To
 972
 973                         q1.As = AADR
 974                         q1.From.Type = obj.TYPE_BRANCH
 975                         q1.To.Type = obj.TYPE_REG
 976                         q1.To.Reg = REG_R27
 977
 978                         q2 := obj.Appendp(q1, c.newprog)
 979                         q2.Pos = p.Pos
 980                         q2.As = ASTP
 981                         q2.From.Type = obj.TYPE_REGREG
 982                         q2.From.Reg = REGFP
 983                         q2.From.Offset = int64(REG_R27)
 984                         q2.To.Type = obj.TYPE_MEM
 985                         q2.To.Reg = REGSP
 986                         q2.To.Offset = -24
 987
 988                         // maintain FP for DUFFCOPY
 989                         q3 := obj.Appendp(q2, c.newprog)
 990                         q3.Pos = p.Pos
 991                         q3.As = ASUB
 992                         q3.From.Type = obj.TYPE_CONST
 993                         q3.From.Offset = 24
 994                         q3.Reg = REGSP
 995                         q3.To.Type = obj.TYPE_REG
 996                         q3.To.Reg = REGFP
 997
 998                         q5 := obj.Appendp(q4, c.newprog)
 999                         q5.Pos = p.Pos
1000                         q5.As = ASUB
1001                         q5.From.Type = obj.TYPE_CONST
1002                         q5.From.Offset = 8
1003                         q5.Reg = REGSP
1004                         q5.To.Type = obj.TYPE_REG
1005                         q5.To.Reg = REGFP
1006                         q1.From.SetTarget(q5)
1007                         p = q5
1008
1009                 case obj.ADUFFZERO:
1010                         //  ADR ret_addr, R27
1011                         //  STP (FP, R27), -24(SP)
1012                         //  SUB 24, SP, FP
1013                         //  DUFFZERO
1014                         // ret_addr:
1015                         //  SUB 8, SP, FP
1016
1017                         q1 := p
1018                         // copy DUFFZERO from q1 to q4
1019                         q4 := obj.Appendp(p, c.newprog)
1020                         q4.Pos = p.Pos
1021                         q4.As = obj.ADUFFZERO
1022                         q4.To = p.To
1023
1024                         q1.As = AADR
1025                         q1.From.Type = obj.TYPE_BRANCH
1026                         q1.To.Type = obj.TYPE_REG
1027                         q1.To.Reg = REG_R27
1028
1029                         q2 := obj.Appendp(q1, c.newprog)
1030                         q2.Pos = p.Pos
1031                         q2.As = ASTP
1032                         q2.From.Type = obj.TYPE_REGREG
1033                         q2.From.Reg = REGFP
1034                         q2.From.Offset = int64(REG_R27)
1035                         q2.To.Type = obj.TYPE_MEM
1036                         q2.To.Reg = REGSP
1037                         q2.To.Offset = -24
1038
1039                         // maintain FP for DUFFZERO
1040                         q3 := obj.Appendp(q2, c.newprog)
1041                         q3.Pos = p.Pos
1042                         q3.As = ASUB
1043                         q3.From.Type = obj.TYPE_CONST
1044                         q3.From.Offset = 24
1045                         q3.Reg = REGSP
1046                         q3.To.Type = obj.TYPE_REG
1047                         q3.To.Reg = REGFP
1048
1049                         q5 := obj.Appendp(q4, c.newprog)
1050                         q5.Pos = p.Pos
1051                         q5.As = ASUB
1052                         q5.From.Type = obj.TYPE_CONST
1053                         q5.From.Offset = 8
1054                         q5.Reg = REGSP
1055                         q5.To.Type = obj.TYPE_REG
1056                         q5.To.Reg = REGFP
1057                         q1.From.SetTarget(q5)
1058                         p = q5
1059                 }
1060
1061                 if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.Spadj == 0 {
1062                         f := c.cursym.Func()
1063                         if f.FuncFlag&objabi.FuncFlag_SPWRITE == 0 {
1064                                 c.cursym.Func().FuncFlag |= objabi.FuncFlag_SPWRITE
1065                                 if ctxt.Debugvlog || !ctxt.IsAsm {
1066                                         ctxt.Logf("auto-SPWRITE: %s %v\n", c.cursym.Name, p)
1067                                         if !ctxt.IsAsm {
1068                                                 ctxt.Diag("invalid auto-SPWRITE in non-assembly")
1069                                                 ctxt.DiagFlush()
1070                                                 log.Fatalf("bad SPWRITE")
1071                                         }
1072                                 }
1073                         }
1074                 }
1075                 if p.From.Type == obj.TYPE_SHIFT && (p.To.Reg == REG_RSP || p.Reg == REG_RSP) {
1076                         offset := p.From.Offset
1077                         op := offset & (3 << 22)
1078                         if op != SHIFT_LL {
1079                                 ctxt.Diag("illegal combination: %v", p)
1080                         }
1081                         r := (offset >> 16) & 31
1082                         shift := (offset >> 10) & 63
1083                         if shift > 4 {
1084                                 // the shift amount is out of range, in order to avoid repeated error
1085                                 // reportings, don't call ctxt.Diag, because asmout case 27 has the
1086                                 // same check.
1087                                 shift = 7
1088                         }
1089                         p.From.Type = obj.TYPE_REG
1090                         p.From.Reg = int16(REG_LSL + r + (shift&7)<<5)
1091                         p.From.Offset = 0
1092                 }
1093         }
1094 }
1095
1096 func nocache(p *obj.Prog) {
1097         p.Optab = 0
1098         p.From.Class = 0
1099         p.To.Class = 0
1100 }
1101
1102 var unaryDst = map[obj.As]bool{
1103         AWORD:  true,
1104         ADWORD: true,
1105         ABL:    true,
1106         AB:     true,
1107         ACLREX: true,
1108 }
1109
1110 var Linkarm64 = obj.LinkArch{
1111         Arch:           sys.ArchARM64,
1112         Init:           buildop,
1113         Preprocess:     preprocess,
1114         Assemble:       span7,
1115         Progedit:       progedit,
1116         UnaryDst:       unaryDst,
1117         DWARFRegisters: ARM64DWARFRegisters,
1118 }