// cmd/7l/noop.c, cmd/7l/obj.c, cmd/ld/pass.c from Vita Nuova.
-// https://code.google.com/p/ken-cc/source/browse/
+// https://bitbucket.org/plan9-from-bell-labs/9-cc/src/master/
//
// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
"cmd/internal/objabi"
"cmd/internal/src"
"cmd/internal/sys"
+ "internal/abi"
"internal/buildcfg"
"log"
"math"
)
-var complements = []obj.As{
- AADD: ASUB,
- AADDW: ASUBW,
- ASUB: AADD,
- ASUBW: AADDW,
- ACMP: ACMN,
- ACMPW: ACMNW,
- ACMN: ACMP,
- ACMNW: ACMPW,
+// zrReplace is the set of instructions for which $0 in the From operand
+// should be replaced with REGZERO.
+var zrReplace = map[obj.As]bool{
+ AMOVD: true,
+ AMOVW: true,
+ AMOVWU: true,
+ AMOVH: true,
+ AMOVHU: true,
+ AMOVB: true,
+ AMOVBU: true,
+ ASBC: true,
+ ASBCW: true,
+ ASBCS: true,
+ ASBCSW: true,
+ AADC: true,
+ AADCW: true,
+ AADCS: true,
+ AADCSW: true,
+ AFMOVD: true,
+ AFMOVS: true,
+ AMSR: true,
}
func (c *ctxt7) stacksplit(p *obj.Prog, framesize int32) *obj.Prog {
+ if c.ctxt.Flag_maymorestack != "" {
+ p = c.cursym.Func().SpillRegisterArgs(p, c.newprog)
+
+ // Save LR and make room for FP, REGCTXT. Leave room
+ // for caller's saved FP.
+ const frameSize = 32
+ p = obj.Appendp(p, c.newprog)
+ p.As = AMOVD
+ p.From.Type = obj.TYPE_REG
+ p.From.Reg = REGLINK
+ p.To.Type = obj.TYPE_MEM
+ p.Scond = C_XPRE
+ p.To.Offset = -frameSize
+ p.To.Reg = REGSP
+ p.Spadj = frameSize
+
+ // Save FP.
+ p = obj.Appendp(p, c.newprog)
+ p.As = AMOVD
+ p.From.Type = obj.TYPE_REG
+ p.From.Reg = REGFP
+ p.To.Type = obj.TYPE_MEM
+ p.To.Reg = REGSP
+ p.To.Offset = -8
+
+ p = obj.Appendp(p, c.newprog)
+ p.As = ASUB
+ p.From.Type = obj.TYPE_CONST
+ p.From.Offset = 8
+ p.Reg = REGSP
+ p.To.Type = obj.TYPE_REG
+ p.To.Reg = REGFP
+
+ // Save REGCTXT (for simplicity we do this whether or
+ // not we need it.)
+ p = obj.Appendp(p, c.newprog)
+ p.As = AMOVD
+ p.From.Type = obj.TYPE_REG
+ p.From.Reg = REGCTXT
+ p.To.Type = obj.TYPE_MEM
+ p.To.Reg = REGSP
+ p.To.Offset = 8
+
+ // BL maymorestack
+ p = obj.Appendp(p, c.newprog)
+ p.As = ABL
+ 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.
+ p = obj.Appendp(p, c.newprog)
+ p.As = AMOVD
+ p.From.Type = obj.TYPE_MEM
+ p.From.Reg = REGSP
+ p.From.Offset = 8
+ p.To.Type = obj.TYPE_REG
+ p.To.Reg = REGCTXT
+
+ // Restore FP.
+ p = obj.Appendp(p, c.newprog)
+ p.As = AMOVD
+ p.From.Type = obj.TYPE_MEM
+ p.From.Reg = REGSP
+ p.From.Offset = -8
+ p.To.Type = obj.TYPE_REG
+ p.To.Reg = REGFP
+
+ // Restore LR and SP.
+ p = obj.Appendp(p, c.newprog)
+ p.As = AMOVD
+ p.From.Type = obj.TYPE_MEM
+ p.Scond = C_XPOST
+ p.From.Offset = frameSize
+ p.From.Reg = REGSP
+ p.To.Type = obj.TYPE_REG
+ p.To.Reg = REGLINK
+ p.Spadj = -frameSize
+
+ p = c.cursym.Func().UnspillRegisterArgs(p, c.newprog)
+ }
+
+ // Jump back to here after morestack returns.
+ startPred := p
+
// MOV g_stackguard(g), RT1
p = obj.Appendp(p, c.newprog)
p = c.ctxt.StartUnsafePoint(p, c.newprog)
q := (*obj.Prog)(nil)
- if framesize <= objabi.StackSmall {
+ if framesize <= abi.StackSmall {
// small stack: SP < stackguard
- // MOV SP, RT2
- // CMP stackguard, RT2
- p = obj.Appendp(p, c.newprog)
-
- p.As = AMOVD
- p.From.Type = obj.TYPE_REG
- p.From.Reg = REGSP
- p.To.Type = obj.TYPE_REG
- p.To.Reg = REGRT2
+ // CMP stackguard, SP
p = obj.Appendp(p, c.newprog)
p.As = ACMP
p.From.Type = obj.TYPE_REG
p.From.Reg = REGRT1
- p.Reg = REGRT2
- } else if framesize <= objabi.StackBig {
+ p.Reg = REGSP
+ } else if framesize <= abi.StackBig {
// large stack: SP-framesize < stackguard-StackSmall
// SUB $(framesize-StackSmall), SP, RT2
// CMP stackguard, RT2
p.As = ASUB
p.From.Type = obj.TYPE_CONST
- p.From.Offset = int64(framesize) - objabi.StackSmall
+ p.From.Offset = int64(framesize) - abi.StackSmall
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REGRT2
p = obj.Appendp(p, c.newprog)
p.As = ASUBS
p.From.Type = obj.TYPE_CONST
- p.From.Offset = int64(framesize) - objabi.StackSmall
+ p.From.Offset = int64(framesize) - abi.StackSmall
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REGRT2
}
call.To.Sym = c.ctxt.Lookup(morestack)
- unspill := c.cursym.Func().UnspillRegisterArgs(call, c.newprog)
- pcdata = c.ctxt.EndUnsafePoint(unspill, c.newprog, -1)
+ // The instructions which unspill regs should be preemptible.
+ pcdata = c.ctxt.EndUnsafePoint(call, c.newprog, -1)
+ unspill := c.cursym.Func().UnspillRegisterArgs(pcdata, c.newprog)
// B start
- jmp := obj.Appendp(pcdata, c.newprog)
+ jmp := obj.Appendp(unspill, c.newprog)
jmp.As = AB
jmp.To.Type = obj.TYPE_BRANCH
- jmp.To.SetTarget(c.cursym.Func().Text.Link)
+ jmp.To.SetTarget(startPred.Link)
jmp.Spadj = +framesize
return end
p.From.Class = 0
p.To.Class = 0
- // $0 results in C_ZCON, which matches both C_REG and various
- // C_xCON, however the C_REG cases in asmout don't expect a
- // constant, so they will use the register fields and assemble
- // a R0. To prevent that, rewrite $0 as ZR.
- if p.From.Type == obj.TYPE_CONST && p.From.Offset == 0 {
+ // Previously we rewrote $0 to ZR, but we have now removed this change.
+ // In order to be compatible with some previous legal instruction formats,
+ // reserve the previous conversion for some specific instructions.
+ if p.From.Type == obj.TYPE_CONST && p.From.Offset == 0 && zrReplace[p.As] {
p.From.Type = obj.TYPE_REG
p.From.Reg = REGZERO
}
- if p.To.Type == obj.TYPE_CONST && p.To.Offset == 0 {
- p.To.Type = obj.TYPE_REG
- p.To.Reg = REGZERO
- }
// Rewrite BR/BL to symbol as TYPE_BRANCH.
switch p.As {
break
}
- // Rewrite float constants to values stored in memory.
+ // Rewrite float and vector constants to values stored in memory.
switch p.As {
+ case AVMOVS:
+ if p.From.Type == obj.TYPE_CONST {
+ p.From.Type = obj.TYPE_MEM
+ p.From.Sym = c.ctxt.Int32Sym(p.From.Offset)
+ p.From.Name = obj.NAME_EXTERN
+ p.From.Offset = 0
+ }
+
+ case AVMOVD:
+ if p.From.Type == obj.TYPE_CONST {
+ p.From.Type = obj.TYPE_MEM
+ p.From.Sym = c.ctxt.Int64Sym(p.From.Offset)
+ p.From.Name = obj.NAME_EXTERN
+ p.From.Offset = 0
+ }
+
+ case AVMOVQ:
+ if p.From.Type == obj.TYPE_CONST {
+ p.From.Type = obj.TYPE_MEM
+ p.From.Sym = c.ctxt.Int128Sym(p.GetFrom3().Offset, p.From.Offset)
+ p.From.Name = obj.NAME_EXTERN
+ p.From.Offset = 0
+ p.RestArgs = nil
+ }
+
case AFMOVS:
if p.From.Type == obj.TYPE_FCONST {
f64 := p.From.Val.(float64)
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
-
- break
- }
-
- // Rewrite negative immediates as positive immediates with
- // complementary instruction.
- switch p.As {
- case AADD, ASUB, ACMP, ACMN:
- if p.From.Type == obj.TYPE_CONST && p.From.Offset < 0 && p.From.Offset != -1<<63 {
- p.From.Offset = -p.From.Offset
- p.As = complements[p.As]
- }
- case AADDW, ASUBW, ACMPW, ACMNW:
- if p.From.Type == obj.TYPE_CONST && p.From.Offset < 0 && int32(p.From.Offset) != -1<<31 {
- p.From.Offset = -p.From.Offset
- p.As = complements[p.As]
- }
- }
-
- // For 32-bit instruction with constant, rewrite
- // the high 32-bit to be a repetition of the low
- // 32-bit, so that the BITCON test can be shared
- // for both 32-bit and 64-bit. 32-bit ops will
- // zero the high 32-bit of the destination register
- // anyway.
- if (isANDWop(p.As) || isADDWop(p.As) || p.As == AMOVW) && p.From.Type == obj.TYPE_CONST {
- v := p.From.Offset & 0xffffffff
- p.From.Offset = v | v<<32
}
if c.ctxt.Flag_dynlink {
}
}
- if p.Mark&LEAF != 0 && c.autosize < objabi.StackSmall {
+ if p.Mark&LEAF != 0 && c.autosize < abi.StackSmall {
// A leaf function with a small stack can be marked
// NOSPLIT, avoiding a stack check.
p.From.Sym.Set(obj.AttrNoSplit, true)
var prologueEnd *obj.Prog
aoffset := c.autosize
- if aoffset > 0xF0 {
- aoffset = 0xF0
+ if aoffset > 0xf0 {
+ // MOVD.W offset variant range is -0x100 to 0xf8, SP should be 16-byte aligned.
+ // so the maximum aoffset value is 0xf0.
+ aoffset = 0xf0
}
// Frame is non-empty. Make sure to save link register, even if
// it is a leaf function, so that traceback works.
q = p
if c.autosize > aoffset {
- // Frame size is too large for a MOVD.W instruction.
- // Store link register before decrementing SP, so if a signal comes
- // during the execution of the function prologue, the traceback
- // code will not see a half-updated stack frame.
- // This sequence is not async preemptible, as if we open a frame
- // at the current SP, it will clobber the saved LR.
- q = c.ctxt.StartUnsafePoint(q, c.newprog)
+ // Frame size is too large for a MOVD.W instruction. Store the frame pointer
+ // register and link register before decrementing SP, so if a signal comes
+ // during the execution of the function prologue, the traceback code will
+ // not see a half-updated stack frame.
- q = obj.Appendp(q, c.newprog)
- q.Pos = p.Pos
- q.As = ASUB
- q.From.Type = obj.TYPE_CONST
- q.From.Offset = int64(c.autosize)
- q.Reg = REGSP
- q.To.Type = obj.TYPE_REG
- q.To.Reg = REGTMP
+ // SUB $autosize, RSP, R20
+ q1 = obj.Appendp(q, c.newprog)
+ q1.Pos = p.Pos
+ q1.As = ASUB
+ q1.From.Type = obj.TYPE_CONST
+ q1.From.Offset = int64(c.autosize)
+ q1.Reg = REGSP
+ q1.To.Type = obj.TYPE_REG
+ q1.To.Reg = REG_R20
- prologueEnd = q
+ prologueEnd = q1
- q = obj.Appendp(q, c.newprog)
- q.Pos = p.Pos
- q.As = AMOVD
- q.From.Type = obj.TYPE_REG
- q.From.Reg = REGLINK
- q.To.Type = obj.TYPE_MEM
- q.To.Reg = REGTMP
+ // STP (R29, R30), -8(R20)
+ q1 = obj.Appendp(q1, c.newprog)
+ q1.Pos = p.Pos
+ q1.As = ASTP
+ q1.From.Type = obj.TYPE_REGREG
+ q1.From.Reg = REGFP
+ q1.From.Offset = REGLINK
+ q1.To.Type = obj.TYPE_MEM
+ q1.To.Reg = REG_R20
+ q1.To.Offset = -8
- q1 = obj.Appendp(q, c.newprog)
+ // This is not async preemptible, as if we open a frame
+ // at the current SP, it will clobber the saved LR.
+ q1 = c.ctxt.StartUnsafePoint(q1, c.newprog)
+
+ // MOVD R20, RSP
+ q1 = obj.Appendp(q1, c.newprog)
q1.Pos = p.Pos
q1.As = AMOVD
q1.From.Type = obj.TYPE_REG
- q1.From.Reg = REGTMP
+ q1.From.Reg = REG_R20
q1.To.Type = obj.TYPE_REG
q1.To.Reg = REGSP
q1.Spadj = c.autosize
+ q1 = c.ctxt.EndUnsafePoint(q1, c.newprog, -1)
+
if buildcfg.GOOS == "ios" {
// iOS does not support SA_ONSTACK. We will run the signal handler
// on the G stack. If we write below SP, it may be clobbered by
- // the signal handler. So we save LR after decrementing SP.
+ // the signal handler. So we save FP and LR after decrementing SP.
+ // STP (R29, R30), -8(RSP)
q1 = obj.Appendp(q1, c.newprog)
q1.Pos = p.Pos
- q1.As = AMOVD
- q1.From.Type = obj.TYPE_REG
- q1.From.Reg = REGLINK
+ q1.As = ASTP
+ q1.From.Type = obj.TYPE_REGREG
+ q1.From.Reg = REGFP
+ q1.From.Offset = REGLINK
q1.To.Type = obj.TYPE_MEM
q1.To.Reg = REGSP
+ q1.To.Offset = -8
}
-
- q1 = c.ctxt.EndUnsafePoint(q1, c.newprog, -1)
} else {
- // small frame, update SP and save LR in a single MOVD.W instruction
+ // small frame, update SP and save LR in a single MOVD.W instruction.
+ // So if a signal comes during the execution of the function prologue,
+ // the traceback code will not see a half-updated stack frame.
+ // Also, on Linux, in a cgo binary we may get a SIGSETXID signal
+ // early on before the signal stack is set, as glibc doesn't allow
+ // us to block SIGSETXID. So it is important that we don't write below
+ // the SP until the signal stack is set.
+ // Luckily, all the functions from thread entry to setting the signal
+ // stack have small frames.
q1 = obj.Appendp(q, c.newprog)
q1.As = AMOVD
q1.Pos = p.Pos
q1.Spadj = aoffset
prologueEnd = q1
+
+ // Frame pointer.
+ q1 = obj.Appendp(q1, c.newprog)
+ q1.Pos = p.Pos
+ q1.As = AMOVD
+ q1.From.Type = obj.TYPE_REG
+ q1.From.Reg = REGFP
+ q1.To.Type = obj.TYPE_MEM
+ q1.To.Reg = REGSP
+ q1.To.Offset = -8
}
prologueEnd.Pos = prologueEnd.Pos.WithXlogue(src.PosPrologueEnd)
- // Frame pointer.
- q1 = obj.Appendp(q1, c.newprog)
- q1.Pos = p.Pos
- q1.As = AMOVD
- q1.From.Type = obj.TYPE_REG
- q1.From.Reg = REGFP
- q1.To.Type = obj.TYPE_MEM
- q1.To.Reg = REGSP
- q1.To.Offset = -8
-
q1 = obj.Appendp(q1, c.newprog)
q1.Pos = p.Pos
q1.As = ASUB
p.To = obj.Addr{}
if c.cursym.Func().Text.Mark&LEAF != 0 {
if c.autosize != 0 {
+ // Restore frame pointer.
+ // ADD $framesize-8, RSP, R29
p.As = AADD
p.From.Type = obj.TYPE_CONST
- p.From.Offset = int64(c.autosize)
+ p.From.Offset = int64(c.autosize) - 8
+ p.Reg = REGSP
p.To.Type = obj.TYPE_REG
- p.To.Reg = REGSP
- p.Spadj = -c.autosize
+ p.To.Reg = REGFP
- // Frame pointer.
+ // Pop stack frame.
+ // ADD $framesize, RSP, RSP
p = obj.Appendp(p, c.newprog)
- p.As = ASUB
+ p.As = AADD
p.From.Type = obj.TYPE_CONST
- p.From.Offset = 8
- p.Reg = REGSP
+ p.From.Offset = int64(c.autosize)
p.To.Type = obj.TYPE_REG
- p.To.Reg = REGFP
+ p.To.Reg = REGSP
+ p.Spadj = -c.autosize
}
} else {
- /* want write-back pre-indexed SP+autosize -> SP, loading REGLINK*/
-
- // Frame pointer.
- p.As = AMOVD
+ aoffset := c.autosize
+ // LDP -8(RSP), (R29, R30)
+ p.As = ALDP
p.From.Type = obj.TYPE_MEM
- p.From.Reg = REGSP
p.From.Offset = -8
- p.To.Type = obj.TYPE_REG
+ p.From.Reg = REGSP
+ p.To.Type = obj.TYPE_REGREG
p.To.Reg = REGFP
- p = obj.Appendp(p, c.newprog)
-
- aoffset := c.autosize
-
- if aoffset <= 0xF0 {
- p.As = AMOVD
- p.From.Type = obj.TYPE_MEM
- p.Scond = C_XPOST
- p.From.Offset = int64(aoffset)
- p.From.Reg = REGSP
- p.To.Type = obj.TYPE_REG
- p.To.Reg = REGLINK
- p.Spadj = -aoffset
- } else {
- p.As = AMOVD
- p.From.Type = obj.TYPE_MEM
- p.From.Offset = 0
- p.From.Reg = REGSP
- p.To.Type = obj.TYPE_REG
- p.To.Reg = REGLINK
+ p.To.Offset = REGLINK
- q = newprog()
- q.As = AADD
- q.From.Type = obj.TYPE_CONST
- q.From.Offset = int64(aoffset)
- q.To.Type = obj.TYPE_REG
- q.To.Reg = REGSP
- q.Link = p.Link
- q.Spadj = int32(-q.From.Offset)
- q.Pos = p.Pos
- p.Link = q
- p = q
- }
+ // ADD $aoffset, RSP, RSP
+ q = newprog()
+ q.As = AADD
+ q.From.Type = obj.TYPE_CONST
+ q.From.Offset = int64(aoffset)
+ q.To.Type = obj.TYPE_REG
+ q.To.Reg = REGSP
+ q.Spadj = -aoffset
+ q.Pos = p.Pos
+ q.Link = p.Link
+ p.Link = q
+ p = q
}
// If enabled, this code emits 'MOV PC, R27' before every 'MOV LR, PC',
if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.Spadj == 0 {
f := c.cursym.Func()
- if f.FuncFlag&objabi.FuncFlag_SPWRITE == 0 {
- c.cursym.Func().FuncFlag |= objabi.FuncFlag_SPWRITE
+ 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 {
}
}
}
+ if p.From.Type == obj.TYPE_SHIFT && (p.To.Reg == REG_RSP || p.Reg == REG_RSP) {
+ offset := p.From.Offset
+ op := offset & (3 << 22)
+ if op != SHIFT_LL {
+ ctxt.Diag("illegal combination: %v", p)
+ }
+ r := (offset >> 16) & 31
+ shift := (offset >> 10) & 63
+ if shift > 4 {
+ // the shift amount is out of range, in order to avoid repeated error
+ // reportings, don't call ctxt.Diag, because asmout case 27 has the
+ // same check.
+ shift = 7
+ }
+ p.From.Type = obj.TYPE_REG
+ p.From.Reg = int16(REG_LSL + r + (shift&7)<<5)
+ p.From.Offset = 0
+ }
}
}