Ejemplo n.º 1
0
func findu1(r *gc.Flow, v *obj.Addr) bool {
	for ; r != nil; r = r.S1 {
		if r.Active != 0 {
			return false
		}
		r.Active = 1
		switch copyu(r.Prog, v, nil) {
		case 1, /* used */
			2, /* read-alter-rewrite */
			4: /* set and used */
			return true

		case 3: /* set */
			return false
		}

		if r.S2 != nil {
			if findu1(r.S2, v) {
				return true
			}
		}
	}

	return false
}
Ejemplo n.º 2
0
// copy1 replaces uses of v2 with v1 starting at r and returns true if
// all uses were rewritten.
func copy1(v1 *obj.Addr, v2 *obj.Addr, r *gc.Flow, f int) bool {
	if uint32(r.Active) == gactive {
		return true
	}
	r.Active = int32(gactive)
	for ; r != nil; r = r.S1 {
		p := r.Prog
		if f == 0 && gc.Uniqp(r) == nil {
			// Multiple predecessors; conservatively
			// assume v1 was set on other path
			f = 1
		}
		t := copyu(p, v2, nil)
		switch t {
		case _ReadWriteSame:
			return false
		case _Write:
			return true
		case _Read, _ReadWriteDiff:
			if f != 0 {
				return false
			}
			if copyu(p, v2, v1) != 0 {
				return false
			}
			if t == _ReadWriteDiff {
				return true
			}
		}
		if f == 0 {
			switch copyu(p, v1, nil) {
			case _ReadWriteSame, _ReadWriteDiff, _Write:
				f = 1
			}
		}
		if r.S2 != nil {
			if !copy1(v1, v2, r.S2, f) {
				return false
			}
		}
	}
	return true
}
Ejemplo n.º 3
0
// copy1 replaces uses of v2 with v1 starting at r and returns true if
// all uses were rewritten.
func copy1(v1 *obj.Addr, v2 *obj.Addr, r *gc.Flow, f bool) bool {
	if uint32(r.Active) == gactive {
		if gc.Debug['P'] != 0 {
			fmt.Printf("act set; return 1\n")
		}
		return true
	}

	r.Active = int32(gactive)
	if gc.Debug['P'] != 0 {
		fmt.Printf("copy1 replace %v with %v f=%v\n", gc.Ctxt.Dconv(v2), gc.Ctxt.Dconv(v1), f)
	}
	for ; r != nil; r = r.S1 {
		p := r.Prog
		if gc.Debug['P'] != 0 {
			fmt.Printf("%v", p)
		}
		if !f && gc.Uniqp(r) == nil {
			// Multiple predecessors; conservatively
			// assume v1 was set on other path
			f = true

			if gc.Debug['P'] != 0 {
				fmt.Printf("; merge; f=%v", f)
			}
		}

		switch t := copyu(p, v2, nil); t {
		case 2: /* rar, can't split */
			if gc.Debug['P'] != 0 {
				fmt.Printf("; %v rar; return 0\n", gc.Ctxt.Dconv(v2))
			}
			return false

		case 3: /* set */
			if gc.Debug['P'] != 0 {
				fmt.Printf("; %v set; return 1\n", gc.Ctxt.Dconv(v2))
			}
			return true

		case 1, /* used, substitute */
			4: /* use and set */
			if f {
				if gc.Debug['P'] == 0 {
					return false
				}
				if t == 4 {
					fmt.Printf("; %v used+set and f=%v; return 0\n", gc.Ctxt.Dconv(v2), f)
				} else {
					fmt.Printf("; %v used and f=%v; return 0\n", gc.Ctxt.Dconv(v2), f)
				}
				return false
			}

			if copyu(p, v2, v1) != 0 {
				if gc.Debug['P'] != 0 {
					fmt.Printf("; sub fail; return 0\n")
				}
				return false
			}

			if gc.Debug['P'] != 0 {
				fmt.Printf("; sub %v->%v\n => %v", gc.Ctxt.Dconv(v2), gc.Ctxt.Dconv(v1), p)
			}
			if t == 4 {
				if gc.Debug['P'] != 0 {
					fmt.Printf("; %v used+set; return 1\n", gc.Ctxt.Dconv(v2))
				}
				return true
			}
		}

		if !f {
			t := copyu(p, v1, nil)
			if t == 2 || t == 3 || t == 4 {
				f = true
				if gc.Debug['P'] != 0 {
					fmt.Printf("; %v set and !f; f=%v", gc.Ctxt.Dconv(v1), f)
				}
			}
		}

		if gc.Debug['P'] != 0 {
			fmt.Printf("\n")
		}
		if r.S2 != nil {
			if !copy1(v1, v2, r.S2, f) {
				return false
			}
		}
	}

	return true
}