Example #1
0
func readprog(b *bufio.Reader, p *liblink.Prog) {
	if !undef[p] {
		panic("double-def")
	}
	delete(undef, p)
	p.Pc = rdint(b)
	p.Lineno = int(rdint(b))
	p.Link = rdprog(b)
	p.As = int(rdint(b))
	p.Reg = int(rdint(b))
	p.Scond = int(rdint(b))
	p.Width = int8(rdint(b))
	readaddr(b, &p.From)
	readaddr(b, &p.To)
}
Example #2
0
func stacksplit(ctxt *liblink.Link, p *liblink.Prog, framesize int64, noctxt int) *liblink.Prog {
	var arg int
	// MOVW			g_stackguard(g), R1
	p = liblink.Appendp(ctxt, p)
	p.As = AMOVW
	p.From.Typ = D_OREG
	p.From.Reg = REGG
	p.To.Typ = D_REG
	p.To.Reg = 1
	if framesize <= liblink.StackSmall {
		// small stack: SP < stackguard
		//	CMP	stackguard, SP
		p = liblink.Appendp(ctxt, p)
		p.As = ACMP
		p.From.Typ = D_REG
		p.From.Reg = 1
		p.Reg = REGSP
	} else if framesize <= liblink.StackBig {
		// large stack: SP-framesize < stackguard-StackSmall
		//	MOVW $-framesize(SP), R2
		//	CMP stackguard, R2
		p = liblink.Appendp(ctxt, p)
		p.As = AMOVW
		p.From.Typ = D_CONST
		p.From.Reg = REGSP
		p.From.Offset = -framesize
		p.To.Typ = D_REG
		p.To.Reg = 2
		p = liblink.Appendp(ctxt, p)
		p.As = ACMP
		p.From.Typ = D_REG
		p.From.Reg = 1
		p.Reg = 2
	} 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.
		//	CMP $StackPreempt, R1
		//	MOVW.NE $StackGuard(SP), R2
		//	SUB.NE R1, R2
		//	MOVW.NE $(framesize+(StackGuard-StackSmall)), R3
		//	CMP.NE R3, R2
		p = liblink.Appendp(ctxt, p)
		p.As = ACMP
		p.From.Typ = D_CONST
		p.From.Offset = int64(uint32(liblink.StackPreempt & 0xFFFFFFFF))
		p.Reg = 1
		p = liblink.Appendp(ctxt, p)
		p.As = AMOVW
		p.From.Typ = D_CONST
		p.From.Reg = REGSP
		p.From.Offset = liblink.StackGuard
		p.To.Typ = D_REG
		p.To.Reg = 2
		p.Scond = C_SCOND_NE
		p = liblink.Appendp(ctxt, p)
		p.As = ASUB
		p.From.Typ = D_REG
		p.From.Reg = 1
		p.To.Typ = D_REG
		p.To.Reg = 2
		p.Scond = C_SCOND_NE
		p = liblink.Appendp(ctxt, p)
		p.As = AMOVW
		p.From.Typ = D_CONST
		p.From.Offset = framesize + (liblink.StackGuard - liblink.StackSmall)
		p.To.Typ = D_REG
		p.To.Reg = 3
		p.Scond = C_SCOND_NE
		p = liblink.Appendp(ctxt, p)
		p.As = ACMP
		p.From.Typ = D_REG
		p.From.Reg = 3
		p.Reg = 2
		p.Scond = C_SCOND_NE
	}
	// MOVW.LS		$framesize, R1
	p = liblink.Appendp(ctxt, p)
	p.As = AMOVW
	p.Scond = C_SCOND_LS
	p.From.Typ = D_CONST
	p.From.Offset = framesize
	p.To.Typ = D_REG
	p.To.Reg = 1
	// MOVW.LS		$args, R2
	p = liblink.Appendp(ctxt, p)
	p.As = AMOVW
	p.Scond = C_SCOND_LS
	p.From.Typ = D_CONST
	arg = ctxt.Cursym.Text.To.Offset2
	if arg == 1 { // special marker for known 0
		arg = 0
	}
	if arg&3 != 0 {
		ctxt.Diag("misaligned argument size in stack split")
	}
	p.From.Offset = int64(arg)
	p.To.Typ = D_REG
	p.To.Reg = 2
	// MOVW.LS	R14, R3
	p = liblink.Appendp(ctxt, p)
	p.As = AMOVW
	p.Scond = C_SCOND_LS
	p.From.Typ = D_REG
	p.From.Reg = REGLINK
	p.To.Typ = D_REG
	p.To.Reg = 3
	// BL.LS		runtime.morestack(SB) // modifies LR, returns with LO still asserted
	p = liblink.Appendp(ctxt, p)
	p.As = ABL
	p.Scond = C_SCOND_LS
	p.To.Typ = D_BRANCH
	p.To.Sym = ctxt.Symmorestack[noctxt]
	// BLS	start
	p = liblink.Appendp(ctxt, p)
	p.As = ABLS
	p.To.Typ = D_BRANCH
	p.Pcond = ctxt.Cursym.Text.Link
	return p
}
Example #3
0
func addstacksplit(ctxt *liblink.Link, cursym *liblink.LSym) {
	var p *liblink.Prog
	var pl *liblink.Prog
	var q *liblink.Prog
	var q1 *liblink.Prog
	var q2 *liblink.Prog
	var o int
	var autosize int64
	var autoffset int64
	autosize = 0
	if ctxt.Symmorestack[0] == nil {
		ctxt.Symmorestack[0] = liblink.Linklookup(ctxt, "runtime.morestack", 0)
		ctxt.Symmorestack[1] = liblink.Linklookup(ctxt, "runtime.morestack_noctxt", 0)
	}
	q = nil
	ctxt.Cursym = cursym
	if cursym.Text == nil || cursym.Text.Link == nil {
		return
	}
	softfloat(ctxt, cursym)
	p = cursym.Text
	autoffset = p.To.Offset
	if autoffset < 0 {
		autoffset = 0
	}
	cursym.Locals = autoffset
	cursym.Args = p.To.Offset2
	if ctxt.Debugzerostack != 0 {
		if autoffset != 0 && p.Reg&liblink.NOSPLIT == 0 {
			// MOVW $4(R13), R1
			p = liblink.Appendp(ctxt, p)
			p.As = AMOVW
			p.From.Typ = D_CONST
			p.From.Reg = 13
			p.From.Offset = 4
			p.To.Typ = D_REG
			p.To.Reg = 1
			// MOVW $n(R13), R2
			p = liblink.Appendp(ctxt, p)
			p.As = AMOVW
			p.From.Typ = D_CONST
			p.From.Reg = 13
			p.From.Offset = 4 + autoffset
			p.To.Typ = D_REG
			p.To.Reg = 2
			// MOVW $0, R3
			p = liblink.Appendp(ctxt, p)
			p.As = AMOVW
			p.From.Typ = D_CONST
			p.From.Offset = 0
			p.To.Typ = D_REG
			p.To.Reg = 3
			// L:
			//	MOVW.nil R3, 0(R1) +4
			//	CMP R1, R2
			//	BNE L
			pl = liblink.Appendp(ctxt, p)
			p = pl
			p.As = AMOVW
			p.From.Typ = D_REG
			p.From.Reg = 3
			p.To.Typ = D_OREG
			p.To.Reg = 1
			p.To.Offset = 4
			p.Scond |= C_PBIT
			p = liblink.Appendp(ctxt, p)
			p.As = ACMP
			p.From.Typ = D_REG
			p.From.Reg = 1
			p.Reg = 2
			p = liblink.Appendp(ctxt, p)
			p.As = ABNE
			p.To.Typ = D_BRANCH
			p.Pcond = pl
		}
	}
	/*
	 * find leaf subroutines
	 * strip NOPs
	 * expand RET
	 * expand BECOME pseudo
	 */
	for p = cursym.Text; p != nil; p = p.Link {
		switch p.As {
		case ACASE:
			if ctxt.Flag_shared != 0 {
				linkcase(p)
			}
		case ATEXT:
			p.Mark |= LEAF
		case ARET:
			break
		case ADIV,
			ADIVU,
			AMOD,
			AMODU:
			q = p
			if ctxt.Sym_div == nil {
				initdiv(ctxt)
			}
			cursym.Text.Mark &^= LEAF
			continue
		case ANOP:
			q1 = p.Link
			q.Link = q1 /* q is non-nop */
			if q1 != nil {
				q1.Mark |= p.Mark
			}
			continue
		case ABL,
			ABX,
			ADUFFZERO,
			ADUFFCOPY:
			cursym.Text.Mark &^= LEAF
			fallthrough
		case ABCASE,
			AB,
			ABEQ,
			ABNE,
			ABCS,
			ABHS,
			ABCC,
			ABLO,
			ABMI,
			ABPL,
			ABVS,
			ABVC,
			ABHI,
			ABLS,
			ABGE,
			ABLT,
			ABGT,
			ABLE:
			q1 = p.Pcond
			if q1 != nil {
				for q1.As == ANOP {
					q1 = q1.Link
					p.Pcond = q1
				}
			}
			break
		}
		q = p
	}
	for p = cursym.Text; p != nil; p = p.Link {
		o = p.As
		switch o {
		case ATEXT:
			autosize = p.To.Offset + 4
			if autosize <= 4 {
				if cursym.Text.Mark&LEAF != 0 {
					p.To.Offset = -4
					autosize = 0
				}
			}
			if autosize == 0 && cursym.Text.Mark&LEAF == 0 {
				if ctxt.Debugvlog != 0 {
					fmt.Fprintf(ctxt.Bso, "save suppressed in: %s\n", cursym.Name)
					liblink.Bflush(ctxt.Bso)
				}
				cursym.Text.Mark |= LEAF
			}
			if cursym.Text.Mark&LEAF != 0 {
				cursym.Leaf = 1
				if autosize == 0 {
					break
				}
			}
			if p.Reg&liblink.NOSPLIT == 0 {
				p = stacksplit(ctxt, p, autosize, bool2int(cursym.Text.Reg&liblink.NEEDCTXT == 0)) // emit split check
			}
			// MOVW.W		R14,$-autosize(SP)
			p = liblink.Appendp(ctxt, p)
			p.As = AMOVW
			p.Scond |= C_WBIT
			p.From.Typ = D_REG
			p.From.Reg = REGLINK
			p.To.Typ = D_OREG
			p.To.Offset = -autosize
			p.To.Reg = REGSP
			p.Spadj = autosize
			if cursym.Text.Reg&liblink.WRAPPER != 0 {
				// g->panicwrap += autosize;
				// MOVW panicwrap_offset(g), R3
				// ADD $autosize, R3
				// MOVW R3 panicwrap_offset(g)
				p = liblink.Appendp(ctxt, p)
				p.As = AMOVW
				p.From.Typ = D_OREG
				p.From.Reg = REGG
				p.From.Offset = 2 * ctxt.Arch.Ptrsize
				p.To.Typ = D_REG
				p.To.Reg = 3
				p = liblink.Appendp(ctxt, p)
				p.As = AADD
				p.From.Typ = D_CONST
				p.From.Offset = autosize
				p.To.Typ = D_REG
				p.To.Reg = 3
				p = liblink.Appendp(ctxt, p)
				p.As = AMOVW
				p.From.Typ = D_REG
				p.From.Reg = 3
				p.To.Typ = D_OREG
				p.To.Reg = REGG
				p.To.Offset = 2 * ctxt.Arch.Ptrsize
			}
		case ARET:
			nocache_obj5(p)
			if cursym.Text.Mark&LEAF != 0 {
				if autosize == 0 {
					p.As = AB
					p.From = zprg_obj5.From
					if p.To.Sym != nil { // retjmp
						p.To.Typ = D_BRANCH
					} else {
						p.To.Typ = D_OREG
						p.To.Offset = 0
						p.To.Reg = REGLINK
					}
					break
				}
			}
			if cursym.Text.Reg&liblink.WRAPPER != 0 {
				var scond int
				// Preserve original RET's cond, to allow RET.EQ
				// in the implementation of reflect.call.
				scond = p.Scond
				p.Scond = C_SCOND_NONE
				// g->panicwrap -= autosize;
				// MOVW panicwrap_offset(g), R3
				// SUB $autosize, R3
				// MOVW R3 panicwrap_offset(g)
				p.As = AMOVW
				p.From.Typ = D_OREG
				p.From.Reg = REGG
				p.From.Offset = 2 * ctxt.Arch.Ptrsize
				p.To.Typ = D_REG
				p.To.Reg = 3
				p = liblink.Appendp(ctxt, p)
				p.As = ASUB
				p.From.Typ = D_CONST
				p.From.Offset = autosize
				p.To.Typ = D_REG
				p.To.Reg = 3
				p = liblink.Appendp(ctxt, p)
				p.As = AMOVW
				p.From.Typ = D_REG
				p.From.Reg = 3
				p.To.Typ = D_OREG
				p.To.Reg = REGG
				p.To.Offset = 2 * ctxt.Arch.Ptrsize
				p = liblink.Appendp(ctxt, p)
				p.Scond = scond
			}
			p.As = AMOVW
			p.Scond |= C_PBIT
			p.From.Typ = D_OREG
			p.From.Offset = autosize
			p.From.Reg = REGSP
			p.To.Typ = D_REG
			p.To.Reg = REGPC
			// If there are instructions following
			// this ARET, they come from a branch
			// with the same stackframe, so no spadj.
			if p.To.Sym != nil { // retjmp
				p.To.Reg = REGLINK
				q2 = liblink.Appendp(ctxt, p)
				q2.As = AB
				q2.To.Typ = D_BRANCH
				q2.To.Sym = p.To.Sym
				p.To.Sym = nil
				p = q2
			}
		case AADD:
			if p.From.Typ == D_CONST && p.From.Reg == NREG && p.To.Typ == D_REG && p.To.Reg == REGSP {
				p.Spadj = -p.From.Offset
			}
		case ASUB:
			if p.From.Typ == D_CONST && p.From.Reg == NREG && p.To.Typ == D_REG && p.To.Reg == REGSP {
				p.Spadj = p.From.Offset
			}
		case ADIV,
			ADIVU,
			AMOD,
			AMODU:
			if ctxt.Debugdivmod != 0 {
				break
			}
			if p.From.Typ != D_REG {
				break
			}
			if p.To.Typ != D_REG {
				break
			}
			q1 = p
			/* MOV a,4(SP) */
			p = liblink.Appendp(ctxt, p)
			p.As = AMOVW
			p.Lineno = q1.Lineno
			p.From.Typ = D_REG
			p.From.Reg = q1.From.Reg
			p.To.Typ = D_OREG
			p.To.Reg = REGSP
			p.To.Offset = 4
			/* MOV b,REGTMP */
			p = liblink.Appendp(ctxt, p)
			p.As = AMOVW
			p.Lineno = q1.Lineno
			p.From.Typ = D_REG
			p.From.Reg = q1.Reg
			if q1.Reg == NREG {
				p.From.Reg = q1.To.Reg
			}
			p.To.Typ = D_REG
			p.To.Reg = REGTMP
			p.To.Offset = 0
			/* CALL appropriate */
			p = liblink.Appendp(ctxt, p)
			p.As = ABL
			p.Lineno = q1.Lineno
			p.To.Typ = D_BRANCH
			switch o {
			case ADIV:
				p.To.Sym = ctxt.Sym_div
			case ADIVU:
				p.To.Sym = ctxt.Sym_divu
			case AMOD:
				p.To.Sym = ctxt.Sym_mod
			case AMODU:
				p.To.Sym = ctxt.Sym_modu
				break
			}
			/* MOV REGTMP, b */
			p = liblink.Appendp(ctxt, p)
			p.As = AMOVW
			p.Lineno = q1.Lineno
			p.From.Typ = D_REG
			p.From.Reg = REGTMP
			p.From.Offset = 0
			p.To.Typ = D_REG
			p.To.Reg = q1.To.Reg
			/* ADD $8,SP */
			p = liblink.Appendp(ctxt, p)
			p.As = AADD
			p.Lineno = q1.Lineno
			p.From.Typ = D_CONST
			p.From.Reg = NREG
			p.From.Offset = 8
			p.Reg = NREG
			p.To.Typ = D_REG
			p.To.Reg = REGSP
			p.Spadj = -8
			/* Keep saved LR at 0(SP) after SP change. */
			/* MOVW 0(SP), REGTMP; MOVW REGTMP, -8!(SP) */
			/* TODO: Remove SP adjustments; see issue 6699. */
			q1.As = AMOVW
			q1.From.Typ = D_OREG
			q1.From.Reg = REGSP
			q1.From.Offset = 0
			q1.Reg = NREG
			q1.To.Typ = D_REG
			q1.To.Reg = REGTMP
			/* SUB $8,SP */
			q1 = liblink.Appendp(ctxt, q1)
			q1.As = AMOVW
			q1.From.Typ = D_REG
			q1.From.Reg = REGTMP
			q1.Reg = NREG
			q1.To.Typ = D_OREG
			q1.To.Reg = REGSP
			q1.To.Offset = -8
			q1.Scond |= C_WBIT
			q1.Spadj = 8
		case AMOVW:
			if (p.Scond&C_WBIT != 0) && p.To.Typ == D_OREG && p.To.Reg == REGSP {
				p.Spadj = -p.To.Offset
			}
			if (p.Scond&C_PBIT != 0) && p.From.Typ == D_OREG && p.From.Reg == REGSP && p.To.Reg != REGPC {
				p.Spadj = -p.From.Offset
			}
			if p.From.Typ == D_CONST && p.From.Reg == REGSP && p.To.Typ == D_REG && p.To.Reg == REGSP {
				p.Spadj = -p.From.Offset
			}
			break
		}
	}
}