// Based on cmd/internal/obj/ppc64/obj9.go.
//
// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
// Portions Copyright © 1995-1997 C H Forsyth ([email protected])
// Portions Copyright © 1997-1999 Vita Nuova Limited
// Portions Copyright © 2000-2008 Vita Nuova Holdings Limited (www.vitanuova.com)
// Portions Copyright © 2004,2006 Bruce Ellis
// Portions Copyright © 2005-2007 C H Forsyth ([email protected])
// Revisions Copyright © 2000-2008 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 s390x
import (
"cmd/internal/obj"
"cmd/internal/objabi"
"cmd/internal/sys"
"math"
)
func progedit(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) {
p.From.Class = 0
p.To.Class = 0
c := ctxtz{ctxt: ctxt, newprog: newprog}
// Rewrite BR/BL to symbol as TYPE_BRANCH.
switch p.As {
case ABR, ABL, obj.ARET, obj.ADUFFZERO, obj.ADUFFCOPY:
if p.To.Sym != nil {
p.To.Type = obj.TYPE_BRANCH
}
}
// Rewrite float constants to values stored in memory unless they are +0.
switch p.As {
case AFMOVS:
if p.From.Type == obj.TYPE_FCONST {
f32 := float32(p.From.Val.(float64))
if math.Float32bits(f32) == 0 { // +0
break
}
p.From.Type = obj.TYPE_MEM
p.From.Sym = ctxt.Float32Sym(f32)
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
case AFMOVD:
if p.From.Type == obj.TYPE_FCONST {
f64 := p.From.Val.(float64)
if math.Float64bits(f64) == 0 { // +0
break
}
p.From.Type = obj.TYPE_MEM
p.From.Sym = ctxt.Float64Sym(f64)
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
// put constants not loadable by LOAD IMMEDIATE into memory
case AMOVD:
if p.From.Type == obj.TYPE_CONST {
val := p.From.Offset
if int64(int32(val)) != val &&
int64(uint32(val)) != val &&
int64(uint64(val)&(0xffffffff<<32)) != val {
p.From.Type = obj.TYPE_MEM
p.From.Sym = ctxt.Int64Sym(p.From.Offset)
p.From.Name = obj.NAME_EXTERN
p.From.Offset = 0
}
}
}
// Rewrite SUB constants into ADD.
switch p.As {
case ASUBC:
if p.From.Type == obj.TYPE_CONST && isint32(-p.From.Offset) {
p.From.Offset = -p.From.Offset
p.As = AADDC
}
case ASUB:
if p.From.Type == obj.TYPE_CONST && isint32(-p.From.Offset) {
p.From.Offset = -p.From.Offset
p.As = AADD
}
}
if c.ctxt.Flag_dynlink {
c.rewriteToUseGot(p)
}
}
// Rewrite p, if necessary, to access global data via the global offset table.
func (c *ctxtz) rewriteToUseGot(p *obj.Prog) {
// At the moment EXRL instructions are not emitted by the compiler and only reference local symbols in
// assembly code.
if p.As == AEXRL {
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.
// Rewrites must not clobber flags and therefore cannot use the
// ADD instruction.
if p.From.Type == obj.TYPE_ADDR && p.From.Name == obj.NAME_EXTERN && !p.From.Sym.Local() {
// MOVD $sym, Rx becomes MOVD sym@GOT, Rx
// MOVD $sym+<off>, Rx becomes MOVD sym@GOT, Rx or REGTMP2; MOVD $<off>(Rx or REGTMP2), Rx
if p.To.Type != obj.TYPE_REG || p.As != AMOVD {
c.ctxt.Diag("do not know how to handle LEA-type insn to non-register in %v with -dynlink", p)
}
p.From.Type = obj.TYPE_MEM
p.From.Name = obj.NAME_GOTREF
q := p
if p.From.Offset != 0 {
target := p.To.Reg
if target == REG_R0 {
// Cannot use R0 as input to address calculation.
// REGTMP might be used by the assembler.
p.To.Reg = REGTMP2
}
q = obj.Appendp(q, c.newprog)
q.As = AMOVD
q.From.Type = obj.TYPE_ADDR
q.From.Offset = p.From.Offset
q.From.Reg = p.To.Reg
q.To.Type = obj.TYPE_REG
q.To.Reg = target
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
// MOVD sym, Ry becomes MOVD sym@GOT, REGTMP2; MOVD (REGTMP2), Ry
// MOVD Ry, sym becomes MOVD sym@GOT, REGTMP2; MOVD Ry, (REGTMP2)
// 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 = AMOVD
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 = REGTMP2
p2.As = p.As
p2.From = p.From
p2.To = p.To
if p.From.Name == obj.NAME_EXTERN {
p2.From.Reg = REGTMP2
p2.From.Name = obj.NAME_NONE
p2.From.Sym = nil
} else if p.To.Name == obj.NAME_EXTERN {
p2.To.Reg = REGTMP2
p2.To.Name = obj.NAME_NONE
p2.To.Sym = nil
} else {
return
}
obj.Nopout(p)
}
func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
// TODO(minux): add morestack short-cuts with small fixed frame-size.
if cursym.Func.Text == nil || cursym.Func.Text.Link == nil {
return
}
c := ctxtz{ctxt: ctxt, cursym: cursym, newprog: newprog}
p := c.cursym.Func.Text
textstksiz := p.To.Offset
if textstksiz == -8 {
// Compatibility hack.
p.From.Sym.Set(obj.AttrNoFrame, true)
textstksiz = 0
}
if textstksiz%8 != 0 {
c.ctxt.Diag("frame size %d not a multiple of 8", textstksiz)
}
if p.From.Sym.NoFrame() {
if textstksiz != 0 {
c.ctxt.Diag("NOFRAME functions must have a frame size of 0, not %d", textstksiz)
}
}
c.cursym.Func.Args = p.To.Val.(int32)
c.cursym.Func.Locals = int32(textstksiz)
/*
* find leaf subroutines
* strip NOPs
* expand RET
*/
var q *obj.Prog
for p := c.cursym.Func.Text; p != nil; p = p.Link {
switch p.As {
case obj.ATEXT:
q = p
p.Mark |= LEAF
case ABL, ABCL:
q = p
c.cursym.Func.Text.Mark &^= LEAF
fallthrough
case ABC,
ABEQ,
ABGE,
ABGT,
ABLE,
ABLT,
ABLEU,
ABLTU,
ABNE,
ABR,
ABVC,
ABVS,
ACMPBEQ,
ACMPBGE,
ACMPBGT,
ACMPBLE,
ACMPBLT,
ACMPBNE,
ACMPUBEQ,
ACMPUBGE,
ACMPUBGT,
ACMPUBLE,
ACMPUBLT,
ACMPUBNE:
q = p
p.Mark |= BRANCH
if p.Pcond != nil {
q := p.Pcond
for q.As == obj.ANOP {
q = q.Link
p.Pcond = q
}
}
case obj.ANOP:
q.Link = p.Link /* q is non-nop */
p.Link.Mark |= p.Mark
default:
q = p
}
}
autosize := int32(0)
var pLast *obj.Prog
var pPre *obj.Prog
var pPreempt *obj.Prog
wasSplit := false
for p := c.cursym.Func.Text; p != nil; p = p.Link {
pLast = p
switch p.As {
case obj.ATEXT:
autosize = int32(textstksiz)
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 += int32(c.ctxt.FixedFrameSize())
}
if p.Mark&LEAF != 0 && autosize < objabi.StackSmall {
// A leaf function with a small stack can be marked
// NOSPLIT, avoiding a stack check.
p.From.Sym.Set(obj.AttrNoSplit, true)
}
p.To.Offset = int64(autosize)
q := p
if !p.From.Sym.NoSplit() {
p, pPreempt = c.stacksplitPre(p, autosize) // emit pre part of split check
pPre = p
wasSplit = true //need post part of split
}
if autosize != 0 {
// Make sure to save link register for non-empty frame, even if
// it is a leaf function, so that traceback works.
// 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.
q = obj.Appendp(p, c.newprog)
q.As = AMOVD
q.From.Type = obj.TYPE_REG
q.From.Reg = REG_LR
q.To.Type = obj.TYPE_MEM
q.To.Reg = REGSP
q.To.Offset = int64(-autosize)
q = obj.Appendp(q, c.newprog)
q.As = AMOVD
q.From.Type = obj.TYPE_ADDR
q.From.Offset = int64(-autosize)
q.From.Reg = REGSP // not actually needed - REGSP is assumed if no reg is provided
q.To.Type = obj.TYPE_REG
q.To.Reg = REGSP
q.Spadj = autosize
} else if c.cursym.Func.Text.Mark&LEAF == 0 {
// A very few functions that do not return to their caller
// (e.g. gogo) are not identified as leaves but still have
// no frame.
c.cursym.Func.Text.Mark |= LEAF
}
if c.cursym.Func.Text.Mark&LEAF != 0 {
c.cursym.Set(obj.AttrLeaf, true)
break
}
if c.cursym.Func.Text.From.Sym.Wrapper() {
// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
//
// MOVD g_panic(g), R3
// CMP R3, $0
// BEQ end
// MOVD panic_argp(R3), R4
// ADD $(autosize+8), R1, R5
// CMP R4, R5
// BNE end
// ADD $8, R1, R6
// MOVD R6, panic_argp(R3)
// end:
// NOP
//
// The NOP is needed to give the jumps somewhere to land.
// It is a liblink NOP, not a s390x NOP: it encodes to 0 instruction bytes.
q = obj.Appendp(q, c.newprog)
q.As = AMOVD
q.From.Type = obj.TYPE_MEM
q.From.Reg = REGG
q.From.Offset = 4 * int64(c.ctxt.Arch.PtrSize) // G.panic
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_R3
q = obj.Appendp(q, c.newprog)
q.As = ACMP
q.From.Type = obj.TYPE_REG
q.From.Reg = REG_R3
q.To.Type = obj.TYPE_CONST
q.To.Offset = 0
q = obj.Appendp(q, c.newprog)
q.As = ABEQ
q.To.Type = obj.TYPE_BRANCH
p1 := q
q = obj.Appendp(q, c.newprog)
q.As = AMOVD
q.From.Type = obj.TYPE_MEM
q.From.Reg = REG_R3
q.From.Offset = 0 // Panic.argp
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_R4
q = obj.Appendp(q, c.newprog)
q.As = AADD
q.From.Type = obj.TYPE_CONST
q.From.Offset = int64(autosize) + c.ctxt.FixedFrameSize()
q.Reg = REGSP
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_R5
q = obj.Appendp(q, c.newprog)
q.As = ACMP
q.From.Type = obj.TYPE_REG
q.From.Reg = REG_R4
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_R5
q = obj.Appendp(q, c.newprog)
q.As = ABNE
q.To.Type = obj.TYPE_BRANCH
p2 := q
q = obj.Appendp(q, c.newprog)
q.As = AADD
q.From.Type = obj.TYPE_CONST
q.From.Offset = c.ctxt.FixedFrameSize()
q.Reg = REGSP
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_R6
q = obj.Appendp(q, c.newprog)
q.As = AMOVD
q.From.Type = obj.TYPE_REG
q.From.Reg = REG_R6
q.To.Type = obj.TYPE_MEM
q.To.Reg = REG_R3
q.To.Offset = 0 // Panic.argp
q = obj.Appendp(q, c.newprog)
q.As = obj.ANOP
p1.Pcond = q
p2.Pcond = q
}
case obj.ARET:
retTarget := p.To.Sym
if c.cursym.Func.Text.Mark&LEAF != 0 {
if autosize == 0 {
p.As = ABR
p.From = obj.Addr{}
if retTarget == nil {
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_LR
} else {
p.To.Type = obj.TYPE_BRANCH
p.To.Sym = retTarget
}
p.Mark |= BRANCH
break
}
p.As = AADD
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(autosize)
p.To.Type = obj.TYPE_REG
p.To.Reg = REGSP
p.Spadj = -autosize
q = obj.Appendp(p, c.newprog)
q.As = ABR
q.From = obj.Addr{}
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_LR
q.Mark |= BRANCH
q.Spadj = autosize
break
}
p.As = AMOVD
p.From.Type = obj.TYPE_MEM
p.From.Reg = REGSP
p.From.Offset = 0
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_LR
q = p
if autosize != 0 {
q = obj.Appendp(q, c.newprog)
q.As = AADD
q.From.Type = obj.TYPE_CONST
q.From.Offset = int64(autosize)
q.To.Type = obj.TYPE_REG
q.To.Reg = REGSP
q.Spadj = -autosize
}
q = obj.Appendp(q, c.newprog)
q.As = ABR
q.From = obj.Addr{}
if retTarget == nil {
q.To.Type = obj.TYPE_REG
q.To.Reg = REG_LR
} else {
q.To.Type = obj.TYPE_BRANCH
q.To.Sym = retTarget
}
q.Mark |= BRANCH
q.Spadj = autosize
case AADD:
if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.From.Type == obj.TYPE_CONST {
p.Spadj = int32(-p.From.Offset)
}
case obj.AGETCALLERPC:
if cursym.Leaf() {
/* MOVD LR, Rd */
p.As = AMOVD
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_LR
} else {
/* MOVD (RSP), Rd */
p.As = AMOVD
p.From.Type = obj.TYPE_MEM
p.From.Reg = REGSP
}
}
}
if wasSplit {
c.stacksplitPost(pLast, pPre, pPreempt, autosize) // emit post part of split check
}
}
func (c *ctxtz) stacksplitPre(p *obj.Prog, framesize int32) (*obj.Prog, *obj.Prog) {
var q *obj.Prog
// MOVD g_stackguard(g), R3
p = obj.Appendp(p, c.newprog)
p.As = AMOVD
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_R3
q = nil
if framesize <= objabi.StackSmall {
// small stack: SP < stackguard
// CMP stackguard, SP
//p.To.Type = obj.TYPE_REG
//p.To.Reg = REGSP
// q1: BLT done
p = obj.Appendp(p, c.newprog)
//q1 = p
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R3
p.Reg = REGSP
p.As = ACMPUBGE
p.To.Type = obj.TYPE_BRANCH
//p = obj.Appendp(ctxt, p)
//p.As = ACMPU
//p.From.Type = obj.TYPE_REG
//p.From.Reg = REG_R3
//p.To.Type = obj.TYPE_REG
//p.To.Reg = REGSP
//p = obj.Appendp(ctxt, p)
//p.As = ABGE
//p.To.Type = obj.TYPE_BRANCH
} else if framesize <= objabi.StackBig {
// large stack: SP-framesize < stackguard-StackSmall
// ADD $-(framesize-StackSmall), SP, R4
// CMP stackguard, R4
p = obj.Appendp(p, c.newprog)
p.As = AADD
p.From.Type = obj.TYPE_CONST
p.From.Offset = -(int64(framesize) - objabi.StackSmall)
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R4
p = obj.Appendp(p, c.newprog)
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R3
p.Reg = REG_R4
p.As = ACMPUBGE
p.To.Type = obj.TYPE_BRANCH
} else {
// Such a large stack we need to protect against wraparound.
// If SP is close to zero:
// SP-stackguard+StackGuard <= framesize + (StackGuard-StackSmall)
// The +StackGuard on both sides is required to keep the left side positive:
// SP is allowed to be slightly below stackguard. See stack.h.
//
// Preemption sets stackguard to StackPreempt, a very large value.
// That breaks the math above, so we have to check for that explicitly.
// // stackguard is R3
// CMP R3, $StackPreempt
// BEQ label-of-call-to-morestack
// ADD $StackGuard, SP, R4
// SUB R3, R4
// MOVD $(framesize+(StackGuard-StackSmall)), TEMP
// CMPUBGE TEMP, R4
p = obj.Appendp(p, c.newprog)
p.As = ACMP
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R3
p.To.Type = obj.TYPE_CONST
p.To.Offset = objabi.StackPreempt
p = obj.Appendp(p, c.newprog)
q = p
p.As = ABEQ
p.To.Type = obj.TYPE_BRANCH
p = obj.Appendp(p, c.newprog)
p.As = AADD
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(objabi.StackGuard)
p.Reg = REGSP
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R4
p = obj.Appendp(p, c.newprog)
p.As = ASUB
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_R3
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R4
p = obj.Appendp(p, c.newprog)
p.As = AMOVD
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(framesize) + int64(objabi.StackGuard) - objabi.StackSmall
p.To.Type = obj.TYPE_REG
p.To.Reg = REGTMP
p = obj.Appendp(p, c.newprog)
p.From.Type = obj.TYPE_REG
p.From.Reg = REGTMP
p.Reg = REG_R4
p.As = ACMPUBGE
p.To.Type = obj.TYPE_BRANCH
}
return p, q
}
func (c *ctxtz) stacksplitPost(p *obj.Prog, pPre *obj.Prog, pPreempt *obj.Prog, framesize int32) *obj.Prog {
// 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(p, c.newprog)
spfix.As = obj.ANOP
spfix.Spadj = -framesize
pcdata := c.ctxt.EmitEntryLiveness(c.cursym, spfix, c.newprog)
// MOVD LR, R5
p = obj.Appendp(pcdata, c.newprog)
pPre.Pcond = p
p.As = AMOVD
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_LR
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_R5
if pPreempt != nil {
pPreempt.Pcond = p
}
// BL runtime.morestack(SB)
p = obj.Appendp(p, c.newprog)
p.As = ABL
p.To.Type = obj.TYPE_BRANCH
if c.cursym.CFunc() {
p.To.Sym = c.ctxt.Lookup("runtime.morestackc")
} else if !c.cursym.Func.Text.From.Sym.NeedCtxt() {
p.To.Sym = c.ctxt.Lookup("runtime.morestack_noctxt")
} else {
p.To.Sym = c.ctxt.Lookup("runtime.morestack")
}
// BR start
p = obj.Appendp(p, c.newprog)
p.As = ABR
p.To.Type = obj.TYPE_BRANCH
p.Pcond = c.cursym.Func.Text.Link
return p
}
var unaryDst = map[obj.As]bool{
ASTCK: true,
ASTCKC: true,
ASTCKE: true,
ASTCKF: true,
ANEG: true,
ANEGW: true,
AVONE: true,
AVZERO: true,
}
var Links390x = obj.LinkArch{
Arch: sys.ArchS390X,
Init: buildop,
Preprocess: preprocess,
Assemble: spanz,
Progedit: progedit,
UnaryDst: unaryDst,
DWARFRegisters: S390XDWARFRegisters,
}
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