Ejemplo n.º 1
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
		}
	}
}
Ejemplo n.º 2
0
func progedit(ctxt *liblink.Link, p *liblink.Prog) {
	var literal string
	var s *liblink.LSym
	var q *liblink.Prog
	// Thread-local storage references use the TLS pseudo-register.
	// As a register, TLS refers to the thread-local storage base, and it
	// can only be loaded into another register:
	//
	//         MOVQ TLS, AX
	//
	// An offset from the thread-local storage base is written off(reg)(TLS*1).
	// Semantically it is off(reg), but the (TLS*1) annotation marks this as
	// indexing from the loaded TLS base. This emits a relocation so that
	// if the linker needs to adjust the offset, it can. For example:
	//
	//         MOVQ TLS, AX
	//         MOVQ 8(AX)(TLS*1), CX // load m into CX
	//
	// On systems that support direct access to the TLS memory, this
	// pair of instructions can be reduced to a direct TLS memory reference:
	//
	//         MOVQ 8(TLS), CX // load m into CX
	//
	// The 2-instruction and 1-instruction forms correspond roughly to
	// ELF TLS initial exec mode and ELF TLS local exec mode, respectively.
	//
	// We applies this rewrite on systems that support the 1-instruction form.
	// The decision is made using only the operating system (and probably
	// the -shared flag, eventually), not the link mode. If some link modes
	// on a particular operating system require the 2-instruction form,
	// then all builds for that operating system will use the 2-instruction
	// form, so that the link mode decision can be delayed to link time.
	//
	// In this way, all supported systems use identical instructions to
	// access TLS, and they are rewritten appropriately first here in
	// liblink and then finally using relocations in the linker.
	if canuselocaltls(ctxt) {
		// Reduce TLS initial exec model to TLS local exec model.
		// Sequences like
		//	MOVQ TLS, BX
		//	... off(BX)(TLS*1) ...
		// become
		//	NOP
		//	... off(TLS) ...
		//
		// TODO(rsc): Remove the Hsolaris special case. It exists only to
		// guarantee we are producing byte-identical binaries as before this code.
		// But it should be unnecessary.
		if (p.As == AMOVQ || p.As == AMOVL) && p.From.Typ == D_TLS && D_AX <= p.To.Typ && p.To.Typ <= D_R15 && ctxt.Headtype != liblink.Hsolaris {
			nopout(p)
		}
		if p.From.Index == D_TLS && D_INDIR+D_AX <= p.From.Typ && p.From.Typ <= D_INDIR+D_R15 {
			p.From.Typ = D_INDIR + D_TLS
			p.From.Scale = 0
			p.From.Index = D_NONE
		}
		if p.To.Index == D_TLS && D_INDIR+D_AX <= p.To.Typ && p.To.Typ <= D_INDIR+D_R15 {
			p.To.Typ = D_INDIR + D_TLS
			p.To.Scale = 0
			p.To.Index = D_NONE
		}
	} else {
		// As a courtesy to the C compilers, rewrite TLS local exec load as TLS initial exec load.
		// The instruction
		//	MOVQ off(TLS), BX
		// becomes the sequence
		//	MOVQ TLS, BX
		//	MOVQ off(BX)(TLS*1), BX
		// This allows the C compilers to emit references to m and g using the direct off(TLS) form.
		if (p.As == AMOVQ || p.As == AMOVL) && p.From.Typ == D_INDIR+D_TLS && D_AX <= p.To.Typ && p.To.Typ <= D_R15 {
			q = liblink.Appendp(ctxt, p)
			q.As = p.As
			q.From = p.From
			q.From.Typ = D_INDIR + p.To.Typ
			q.From.Index = D_TLS
			q.From.Scale = 2 // TODO: use 1
			q.To = p.To
			p.From.Typ = D_TLS
			p.From.Index = D_NONE
			p.From.Offset = 0
		}
	}
	// TODO: Remove.
	if ctxt.Headtype == liblink.Hwindows || ctxt.Headtype == liblink.Hplan9 {
		if p.From.Scale == 1 && p.From.Index == D_TLS {
			p.From.Scale = 2
		}
		if p.To.Scale == 1 && p.To.Index == D_TLS {
			p.To.Scale = 2
		}
	}
	if ctxt.Headtype == liblink.Hnacl {
		nacladdr(ctxt, p, &p.From)
		nacladdr(ctxt, p, &p.To)
	}
	// Maintain information about code generation mode.
	if ctxt.Mode == 0 {
		ctxt.Mode = 64
	}
	p.Mode = ctxt.Mode
	switch p.As {
	case AMODE:
		if p.From.Typ == D_CONST || p.From.Typ == D_INDIR+D_NONE {
			switch int(p.From.Offset) {
			case 16,
				32,
				64:
				ctxt.Mode = int(p.From.Offset)
				break
			}
		}
		nopout(p)
		break
	}
	// Rewrite CALL/JMP/RET to symbol as D_BRANCH.
	switch p.As {
	case ACALL,
		AJMP,
		ARET:
		if (p.To.Typ == D_EXTERN || p.To.Typ == D_STATIC) && p.To.Sym != nil {
			p.To.Typ = D_BRANCH
		}
		break
	}
	// Rewrite float constants to values stored in memory.
	switch p.As {
	case AFMOVF,
		AFADDF,
		AFSUBF,
		AFSUBRF,
		AFMULF,
		AFDIVF,
		AFDIVRF,
		AFCOMF,
		AFCOMFP,
		AMOVSS,
		AADDSS,
		ASUBSS,
		AMULSS,
		ADIVSS,
		ACOMISS,
		AUCOMISS:
		if p.From.Typ == D_FCONST {
			var i32 uint32
			var f32 float32
			f32 = float32(p.From.U.Dval)
			i32 = math.Float32bits(f32)
			literal = fmt.Sprintf("$f32.%08x", uint32(i32))
			s = liblink.Linklookup(ctxt, literal, 0)
			if s.Typ == 0 {
				s.Typ = liblink.SRODATA
				liblink.Adduint32(ctxt, s, i32)
				s.Reachable = 0
			}
			p.From.Typ = D_EXTERN
			p.From.Sym = s
			p.From.Offset = 0
		}
	case AFMOVD,
		AFADDD,
		AFSUBD,
		AFSUBRD,
		AFMULD,
		AFDIVD,
		AFDIVRD,
		AFCOMD,
		AFCOMDP,
		AMOVSD,
		AADDSD,
		ASUBSD,
		AMULSD,
		ADIVSD,
		ACOMISD,
		AUCOMISD:
		if p.From.Typ == D_FCONST {
			var i64 uint64
			i64 = math.Float64bits(p.From.U.Dval)
			literal = fmt.Sprintf("$f64.%016x", uint64(i64))
			s = liblink.Linklookup(ctxt, literal, 0)
			if s.Typ == 0 {
				s.Typ = liblink.SRODATA
				liblink.Adduint64(ctxt, s, i64)
				s.Reachable = 0
			}
			p.From.Typ = D_EXTERN
			p.From.Sym = s
			p.From.Offset = 0
		}
		break
	}
}
Ejemplo n.º 3
0
func progedit(ctxt *liblink.Link, p *liblink.Prog) {
	var literal string
	var s *liblink.LSym
	var q *liblink.Prog
	// See obj6.c for discussion of TLS.
	if canuselocaltls(ctxt) {
		// Reduce TLS initial exec model to TLS local exec model.
		// Sequences like
		//	MOVL TLS, BX
		//	... off(BX)(TLS*1) ...
		// become
		//	NOP
		//	... off(TLS) ...
		if p.As == AMOVL && p.From.Typ == D_TLS && D_AX <= p.To.Typ && p.To.Typ <= D_DI {
			p.As = ANOP
			p.From.Typ = D_NONE
			p.To.Typ = D_NONE
		}
		if p.From.Index == D_TLS && D_INDIR+D_AX <= p.From.Typ && p.From.Typ <= D_INDIR+D_DI {
			p.From.Typ = D_INDIR + D_TLS
			p.From.Scale = 0
			p.From.Index = D_NONE
		}
		if p.To.Index == D_TLS && D_INDIR+D_AX <= p.To.Typ && p.To.Typ <= D_INDIR+D_DI {
			p.To.Typ = D_INDIR + D_TLS
			p.To.Scale = 0
			p.To.Index = D_NONE
		}
	} else {
		// As a courtesy to the C compilers, rewrite TLS local exec load as TLS initial exec load.
		// The instruction
		//	MOVL off(TLS), BX
		// becomes the sequence
		//	MOVL TLS, BX
		//	MOVL off(BX)(TLS*1), BX
		// This allows the C compilers to emit references to m and g using the direct off(TLS) form.
		if p.As == AMOVL && p.From.Typ == D_INDIR+D_TLS && D_AX <= p.To.Typ && p.To.Typ <= D_DI {
			q = liblink.Appendp(ctxt, p)
			q.As = p.As
			q.From = p.From
			q.From.Typ = D_INDIR + p.To.Typ
			q.From.Index = D_TLS
			q.From.Scale = 2 // TODO: use 1
			q.To = p.To
			p.From.Typ = D_TLS
			p.From.Index = D_NONE
			p.From.Offset = 0
		}
	}
	// TODO: Remove.
	if ctxt.Headtype == liblink.Hplan9 {
		if p.From.Scale == 1 && p.From.Index == D_TLS {
			p.From.Scale = 2
		}
		if p.To.Scale == 1 && p.To.Index == D_TLS {
			p.To.Scale = 2
		}
	}
	// Rewrite CALL/JMP/RET to symbol as D_BRANCH.
	switch p.As {
	case ACALL,
		AJMP,
		ARET:
		if (p.To.Typ == D_EXTERN || p.To.Typ == D_STATIC) && p.To.Sym != nil {
			p.To.Typ = D_BRANCH
		}
		break
	}
	// Rewrite float constants to values stored in memory.
	switch p.As {
	case AFMOVF,
		AFADDF,
		AFSUBF,
		AFSUBRF,
		AFMULF,
		AFDIVF,
		AFDIVRF,
		AFCOMF,
		AFCOMFP,
		AMOVSS,
		AADDSS,
		ASUBSS,
		AMULSS,
		ADIVSS,
		ACOMISS,
		AUCOMISS:
		if p.From.Typ == D_FCONST {
			var i32 uint32
			var f32 float32
			f32 = float32(p.From.U.Dval)
			i32 = math.Float32bits(f32)
			literal = fmt.Sprintf("$f32.%08x", uint32(i32))
			s = liblink.Linklookup(ctxt, literal, 0)
			if s.Typ == 0 {
				s.Typ = liblink.SRODATA
				liblink.Adduint32(ctxt, s, i32)
				s.Reachable = 0
			}
			p.From.Typ = D_EXTERN
			p.From.Sym = s
			p.From.Offset = 0
		}
	case AFMOVD,
		AFADDD,
		AFSUBD,
		AFSUBRD,
		AFMULD,
		AFDIVD,
		AFDIVRD,
		AFCOMD,
		AFCOMDP,
		AMOVSD,
		AADDSD,
		ASUBSD,
		AMULSD,
		ADIVSD,
		ACOMISD,
		AUCOMISD:
		if p.From.Typ == D_FCONST {
			var i64 uint64
			i64 = math.Float64bits(p.From.U.Dval)
			literal = fmt.Sprintf("$f64.%016x", uint64(i64))
			s = liblink.Linklookup(ctxt, literal, 0)
			if s.Typ == 0 {
				s.Typ = liblink.SRODATA
				liblink.Adduint64(ctxt, s, i64)
				s.Reachable = 0
			}
			p.From.Typ = D_EXTERN
			p.From.Sym = s
			p.From.Offset = 0
		}
		break
	}
}