| // Based on cmd/internal/obj/ppc64/obj9.go. |
| // |
| // 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 © 2000-2008 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 © 2000-2008 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" |
| "log" |
| "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, |
| ABRC, |
| ABEQ, |
| ABGE, |
| ABGT, |
| ABLE, |
| ABLT, |
| ABLEU, |
| ABLTU, |
| ABNE, |
| ABR, |
| ABVC, |
| ABVS, |
| ACRJ, |
| ACGRJ, |
| ACLRJ, |
| ACLGRJ, |
| ACIJ, |
| ACGIJ, |
| ACLIJ, |
| ACLGIJ, |
| ACMPBEQ, |
| ACMPBGE, |
| ACMPBGT, |
| ACMPBLE, |
| ACMPBLT, |
| ACMPBNE, |
| ACMPUBEQ, |
| ACMPUBGE, |
| ACMPUBGT, |
| ACMPUBLE, |
| ACMPUBLT, |
| ACMPUBNE: |
| q = p |
| p.Mark |= BRANCH |
| |
| default: |
| q = p |
| } |
| } |
| |
| autosize := int32(0) |
| var pLast *obj.Prog |
| var pPre *obj.Prog |
| var pPreempt *obj.Prog |
| var pCheck *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.Arch.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, pCheck = c.stacksplitPre(p, autosize) // emit pre part of split check |
| pPre = p |
| p = c.ctxt.EndUnsafePoint(p, c.newprog, -1) |
| 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. |
| // 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(p, c.newprog) |
| |
| q = obj.Appendp(q, 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 |
| |
| q = c.ctxt.EndUnsafePoint(q, c.newprog, -1) |
| |
| // 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 a signal may land on the current stack and clobber |
| // the content below the SP. We store the LR again after the SP is |
| // decremented. |
| q = obj.Appendp(q, 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 = 0 |
| } 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.Arch.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.Arch.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.To.SetTarget(q) |
| p2.To.SetTarget(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{} |
| 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 |
| break |
| } |
| |
| p.As = AMOVD |
| p.From.Type = obj.TYPE_MEM |
| p.From.Reg = REGSP |
| p.From.Offset = 0 |
| p.To = obj.Addr{ |
| Type: obj.TYPE_REG, |
| 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 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 ctxt.Debugvlog || !ctxt.IsAsm { |
| ctxt.Logf("auto-SPWRITE: %s\n", c.cursym.Name) |
| if !ctxt.IsAsm { |
| ctxt.Diag("invalid auto-SPWRITE in non-assembly") |
| ctxt.DiagFlush() |
| log.Fatalf("bad SPWRITE") |
| } |
| } |
| } |
| } |
| } |
| if wasSplit { |
| c.stacksplitPost(pLast, pPre, pPreempt, pCheck, autosize) // emit post part of split check |
| } |
| } |
| |
| // stacksplitPre generates the function stack check prologue following |
| // Prog p (which should be the TEXT Prog). It returns one or two |
| // branch Progs that must be patched to jump to the morestack epilogue, |
| // and the Prog that starts the morestack check. |
| func (c *ctxtz) stacksplitPre(p *obj.Prog, framesize int32) (pPre, pPreempt, pCheck *obj.Prog) { |
| if c.ctxt.Flag_maymorestack != "" { |
| // Save LR and REGCTXT |
| const frameSize = 16 |
| p = c.ctxt.StartUnsafePoint(p, c.newprog) |
| // MOVD LR, -16(SP) |
| p = obj.Appendp(p, c.newprog) |
| p.As = AMOVD |
| p.From = obj.Addr{Type: obj.TYPE_REG, Reg: REG_LR} |
| p.To = obj.Addr{Type: obj.TYPE_MEM, Reg: REGSP, Offset: -frameSize} |
| // MOVD $-16(SP), SP |
| p = obj.Appendp(p, c.newprog) |
| p.As = AMOVD |
| p.From = obj.Addr{Type: obj.TYPE_ADDR, Offset: -frameSize, Reg: REGSP} |
| p.To = obj.Addr{Type: obj.TYPE_REG, Reg: REGSP} |
| p.Spadj = frameSize |
| // MOVD REGCTXT, 8(SP) |
| p = obj.Appendp(p, c.newprog) |
| p.As = AMOVD |
| p.From = obj.Addr{Type: obj.TYPE_REG, Reg: REGCTXT} |
| p.To = obj.Addr{Type: obj.TYPE_MEM, Reg: REGSP, Offset: 8} |
| |
| // BL maymorestack |
| p = obj.Appendp(p, c.newprog) |
| p.As = ABL |
| // See ../x86/obj6.go |
| sym := c.ctxt.LookupABI(c.ctxt.Flag_maymorestack, c.cursym.ABI()) |
| p.To = obj.Addr{Type: obj.TYPE_BRANCH, Sym: sym} |
| |
| // Restore LR and REGCTXT |
| |
| // MOVD REGCTXT, 8(SP) |
| p = obj.Appendp(p, c.newprog) |
| p.As = AMOVD |
| p.From = obj.Addr{Type: obj.TYPE_MEM, Reg: REGSP, Offset: 8} |
| p.To = obj.Addr{Type: obj.TYPE_REG, Reg: REGCTXT} |
| // MOVD (SP), LR |
| p = obj.Appendp(p, c.newprog) |
| p.As = AMOVD |
| p.From = obj.Addr{Type: obj.TYPE_MEM, Reg: REGSP, Offset: 0} |
| p.To = obj.Addr{Type: obj.TYPE_REG, Reg: REG_LR} |
| // MOVD $16(SP), SP |
| p = obj.Appendp(p, c.newprog) |
| p.As = AMOVD |
| p.From = obj.Addr{Type: obj.TYPE_CONST, Reg: REGSP, Offset: frameSize} |
| p.To = obj.Addr{Type: obj.TYPE_REG, Reg: REGSP} |
| p.Spadj = -frameSize |
| |
| p = c.ctxt.EndUnsafePoint(p, c.newprog, -1) |
| } |
| |
| // MOVD g_stackguard(g), R3 |
| p = obj.Appendp(p, c.newprog) |
| // Jump back to here after morestack returns. |
| pCheck = p |
| |
| 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 |
| |
| // 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 <= objabi.StackSmall { |
| // small stack: SP < stackguard |
| // CMPUBGE stackguard, SP, label-of-call-to-morestack |
| |
| p = obj.Appendp(p, c.newprog) |
| p.From.Type = obj.TYPE_REG |
| p.From.Reg = REG_R3 |
| p.Reg = REGSP |
| p.As = ACMPUBGE |
| p.To.Type = obj.TYPE_BRANCH |
| |
| return p, nil, pCheck |
| } |
| |
| // large stack: SP-framesize < stackguard-StackSmall |
| |
| offset := int64(framesize) - objabi.StackSmall |
| if framesize > objabi.StackBig { |
| // 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. |
| // |
| // MOVD $(framesize-StackSmall), R4 |
| // CMPUBLT SP, R4, label-of-call-to-morestack |
| |
| p = obj.Appendp(p, c.newprog) |
| p.As = AMOVD |
| p.From.Type = obj.TYPE_CONST |
| p.From.Offset = offset |
| p.To.Type = obj.TYPE_REG |
| p.To.Reg = REG_R4 |
| |
| p = obj.Appendp(p, c.newprog) |
| pPreempt = p |
| p.As = ACMPUBLT |
| p.From.Type = obj.TYPE_REG |
| p.From.Reg = REGSP |
| p.Reg = REG_R4 |
| p.To.Type = obj.TYPE_BRANCH |
| } |
| |
| // Check against the stack guard. We've ensured this won't underflow. |
| // ADD $-(framesize-StackSmall), SP, R4 |
| // CMPUBGE stackguard, R4, label-of-call-to-morestack |
| p = obj.Appendp(p, c.newprog) |
| p.As = AADD |
| p.From.Type = obj.TYPE_CONST |
| p.From.Offset = -offset |
| 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 |
| |
| return p, pPreempt, pCheck |
| } |
| |
| // stacksplitPost generates the function epilogue that calls morestack |
| // and returns the new last instruction in the function. |
| // |
| // p is the last Prog in the function. pPre and pPreempt, if non-nil, |
| // are the instructions that branch to the epilogue. This will fill in |
| // their branch targets. pCheck is the Prog that begins the stack check. |
| func (c *ctxtz) stacksplitPost(p *obj.Prog, pPre, pPreempt, pCheck *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.EmitEntryStackMap(c.cursym, spfix, c.newprog) |
| pcdata = c.ctxt.StartUnsafePoint(pcdata, c.newprog) |
| |
| // MOVD LR, R5 |
| p = obj.Appendp(pcdata, c.newprog) |
| pPre.To.SetTarget(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.To.SetTarget(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") |
| } |
| |
| p = c.ctxt.EndUnsafePoint(p, c.newprog, -1) |
| |
| // BR pCheck |
| p = obj.Appendp(p, c.newprog) |
| |
| p.As = ABR |
| p.To.Type = obj.TYPE_BRANCH |
| p.To.SetTarget(pCheck) |
| 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, |
| } |
