github.com/mh-cbon/go@v0.0.0-20160603070303-9e112a3fe4c0/test/escape_map.go (about)

     1  // errorcheck -0 -m -l
     2  
     3  // Copyright 2015 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  // Test escape analysis for maps.
     8  
     9  package escape
    10  
    11  var sink interface{}
    12  
    13  func map0() {
    14  	m := make(map[*int]*int) // ERROR "make\(map\[\*int\]\*int\) does not escape"
    15  	// BAD: i should not escape
    16  	i := 0 // ERROR "moved to heap: i"
    17  	// BAD: j should not escape
    18  	j := 0     // ERROR "moved to heap: j"
    19  	m[&i] = &j // ERROR "&i escapes to heap" "&j escapes to heap"
    20  	_ = m
    21  }
    22  
    23  func map1() *int {
    24  	m := make(map[*int]*int) // ERROR "make\(map\[\*int\]\*int\) does not escape"
    25  	// BAD: i should not escape
    26  	i := 0       // ERROR "moved to heap: i"
    27  	j := 0       // ERROR "moved to heap: j"
    28  	m[&i] = &j   // ERROR "&i escapes to heap" "&j escapes to heap"
    29  	return m[&i] // ERROR "&i does not escape"
    30  }
    31  
    32  func map2() map[*int]*int {
    33  	m := make(map[*int]*int) // ERROR "make\(map\[\*int\]\*int\) escapes to heap"
    34  	i := 0                   // ERROR "moved to heap: i"
    35  	j := 0                   // ERROR "moved to heap: j"
    36  	m[&i] = &j               // ERROR "&i escapes to heap" "&j escapes to heap"
    37  	return m
    38  }
    39  
    40  func map3() []*int {
    41  	m := make(map[*int]*int) // ERROR "make\(map\[\*int\]\*int\) does not escape"
    42  	i := 0                   // ERROR "moved to heap: i"
    43  	// BAD: j should not escape
    44  	j := 0     // ERROR "moved to heap: j"
    45  	m[&i] = &j // ERROR "&i escapes to heap" "&j escapes to heap"
    46  	var r []*int
    47  	for k := range m {
    48  		r = append(r, k)
    49  	}
    50  	return r
    51  }
    52  
    53  func map4() []*int {
    54  	m := make(map[*int]*int) // ERROR "make\(map\[\*int\]\*int\) does not escape"
    55  	// BAD: i should not escape
    56  	i := 0     // ERROR "moved to heap: i"
    57  	j := 0     // ERROR "moved to heap: j"
    58  	m[&i] = &j // ERROR "&i escapes to heap" "&j escapes to heap"
    59  	var r []*int
    60  	for k, v := range m {
    61  		// We want to test exactly "for k, v := range m" rather than "for _, v := range m".
    62  		// The following if is merely to use (but not leak) k.
    63  		if k != nil {
    64  			r = append(r, v)
    65  		}
    66  	}
    67  	return r
    68  }
    69  
    70  func map5(m map[*int]*int) { // ERROR "m does not escape"
    71  	i := 0     // ERROR "moved to heap: i"
    72  	j := 0     // ERROR "moved to heap: j"
    73  	m[&i] = &j // ERROR "&i escapes to heap" "&j escapes to heap"
    74  }
    75  
    76  func map6(m map[*int]*int) { // ERROR "m does not escape"
    77  	if m != nil {
    78  		m = make(map[*int]*int) // ERROR "make\(map\[\*int\]\*int\) does not escape"
    79  	}
    80  	i := 0     // ERROR "moved to heap: i"
    81  	j := 0     // ERROR "moved to heap: j"
    82  	m[&i] = &j // ERROR "&i escapes to heap" "&j escapes to heap"
    83  }
    84  
    85  func map7() {
    86  	// BAD: i should not escape
    87  	i := 0 // ERROR "moved to heap: i"
    88  	// BAD: j should not escape
    89  	j := 0                     // ERROR "moved to heap: j"
    90  	m := map[*int]*int{&i: &j} // ERROR "&i escapes to heap" "&j escapes to heap" "literal does not escape"
    91  	_ = m
    92  }
    93  
    94  func map8() {
    95  	i := 0                     // ERROR "moved to heap: i"
    96  	j := 0                     // ERROR "moved to heap: j"
    97  	m := map[*int]*int{&i: &j} // ERROR "&i escapes to heap" "&j escapes to heap" "literal escapes to heap"
    98  	sink = m // ERROR "m escapes to heap"
    99  }
   100  
   101  func map9() *int {
   102  	// BAD: i should not escape
   103  	i := 0                     // ERROR "moved to heap: i"
   104  	j := 0                     // ERROR "moved to heap: j"
   105  	m := map[*int]*int{&i: &j} // ERROR "&i escapes to heap" "&j escapes to heap" "literal does not escape"
   106  	return m[nil]
   107  }