実践 9 つのメモリリークどう見つける？/ How to detect 9 types of memory leaks?

࣮ફ ͭͷϝϞϦϦʔΫ   Ͳ͏ݟ͚ͭΔʁ J045FTU0OMJOF,VOJXBL

ϝϞϦϦʔΫͱ͸ 2

ϝϞϦϦʔΫͱ͸ɺ΋͏࢖༻͞Εͳ͍   Ϧιʔε͕ϝϞϦʹ֬อ͞Εଓ͚Δ͜ͱ IUUQTFOXJLJQFEJBPSHXJLJ.FNPSZ@MFBLΛ๜༁ɾཁ໿ͨ͠΋ͷɻ೔ຊޠͷํ͸   ͋·Γ͍͍આ໌Ͱ͸ͳ͔ͬͨʜ 3

ϝϞϦϦʔΫ͕͋Δͱɺ࢖͑ΔϝϞϦ͕   ঃʑʹݮ͍ͬͯ͘ ͢ΔͱϝϞϦϓϨογϟʔ͕֤ΞϓϦʹ   ͔͚ΒΕɺͦΕͰ΋ϝϞϦ͕଍Βͳ͍ͱ   ΞϓϦ͕KFUTBNʢւʹϙΠʣ͞ΕΔ ৄ͘͠͸ʮ*EFOUJGZJOHIJHINFNPSZVTFXJUIKFUTBNFWFOUSFQPSUTʯΛࢀরɻ  
IUUQTEFWFMPQFSBQQMFDPNEPDVNFOUBUJPOYDPEFJEFOUJGZJOHIJHINFNPSZVTFXJUIKFUTBNFWFOUSFQPSUT 4

Α͏͢ΔʹϝϞϦϦʔΫͷ͋ΔΞϓϦΛ   ௕࣌ؒ࢖͏ͱڧ੍ऴྃ͞ΕΔˡࠔΔ 5

ϝϞϦϦʔΫ͸Կ͕   ݪҼͰى͜Δͷ͔ 6

॥؀ࢀর 4XJGU͸ࢀরΧ΢ϯτํࣜͳͷͰɺ   ॥؀ࢀর͕͋Δͱ॥؀ࢀরύε্ͷ   ΦϒδΣΫτͷࢀরΧ΢ϯτ͕ʹ   ͳΒͣͥΜͿղ์͞Εͳ͍ 7

ߪಡղআ๨Ε ΋͏Πϕϯτ͕͜ͳ͍ͷʹߪಡΛ   ଓ͚Δͱɺ॥؀ࢀরͰ͸ͳ͍͕   ΋͏࢖ΘΕͳ͍Ϧιʔε͕ϝϞϦʹ   ࢒Γଓ͚ΔͷͰϝϞϦϦʔΫʹͳΔ 8

ϝϞϦϦʔΫΛ   Ͳ͏ݟ͚ͭΔ͔ 9

10 ϝϞϦϦʔΫʹΑΔڧ੍ऴྃͷൃੜΛ஌Δ ϝϞϦϦʔΫ͕ൃੜ͍ͯ͠Δ৔ॴΛߜΓࠐΉ ϝϞϦϦʔΫͷݪҼΛಛఆ͢Δ

11 ϝϞϦϦʔΫ͕ൃੜ͍ͯ͠Δ৔ॴΛߜΓࠐΉ ϝϞϦϦʔΫͷݪҼΛಛఆ͢Δ ࠓ೔ͷൃද͸͜͜ ϝϞϦϦʔΫʹΑΔڧ੍ऴྃͷൃੜΛ஌Δ

9DPEFͷ%FCVH/BWJHBUPS 9DPEFͷ%FCVH.FNPSZ(SBQI *OTUSVNFOUTͷ-FBLT UBSVOPO9$5"TTFSU/P-FBL 12 1 2 3 4

9DPEFͷ%FCVH/BWJHBUPSͷϝϞϦάϥϑ ϝϞϦ࢖༻ྔΛݟΒΕΔ͕   ஫ҙ͕ඞཁʢޙड़ʣ 13 1

9DPEFͷ%FCVH.FNPSZ(SBQI ͜ͷϘλϯΛԡ͢ͱग़Δ΍ͭ 14 2

ΦϒδΣΫτͷࢀরάϥϑΛݟΒΕΔ 15 9DPEFͷ%FCVH.FNPSZ(SBQI 2

ϝϞϦϦʔΫΛݕग़͢Δͱҹ͕ͭ͘ 16 9DPEFͷ%FCVH.FNPSZ(SBQI 2

*OTUSVNFOUTͷ-FBLT ͜ͷϘλϯΛԡ͢ͱग़Δ΍ͭ 17 3

18 3 ϝϞϦϦʔΫΛࣗಈݕग़ͯ͠ఆظతʹݕࠪ݁ՌͷϚʔΫ͕ग़Δ ʜϦʔΫͳ͠ ʜ৽ϦʔΫ͋Γ ʜ৽ϦʔΫͳ͠ *OTUSVNFOUTͷ-FBLT ϝϞϦͷ࢖༻ྔάϥϑ͕ݟΒΕΔ

UBSVOPO9$5"TTFSU/P-FBL 19 4

ϝϞϦϦʔΫΛݕग़͢Δͱςετ͕ࣦഊ͢Δ 20 UBSVOPO9$5"TTFSU/P-FBL 4

ϝϞϦϦʔΫΛݕग़͢Δͱςετ͕ࣦഊ͢Δ 21 UBSVOPO9$5"TTFSU/P-FBL 4

͜ΕΒͷπʔϧΛ࢖ͬͯͭͷ ϝϞϦϦʔΫΛݟͯΈ·͠ΐ͏ 22

ͭͷϝϞϦϦʔΫΛൃੜͤ͞Δ   ΞϓϦΛ༻ҙ͠·ͨ͠ 23

,VOJXBL.FNPSZ-FBL1MBZHSPVOE ʮ&YFSDJTF9ʯΛλοϓ͢Δͱɺ   ͞·͟·ͳछྨͷϝϞϦϦʔΫΛ   Ҿ͖ى͜͠·͢ 24

&YFSDJTF public class Exercise1_1 { var value: Any? private let
weight = Weight1() } public static func exercise1_1() -> Exercise1_1 { let x = Exercise1_1() x.value = x return x } ॥؀ࢀরΛͭ͘Δ άϥϑͷมԽΛΘ͔Γ΍͘͢   ͢ΔͨΊͷେ͖ͳΦϒδΣΫτ 25

&YFSDJTF class Weight1 { private var data: [UInt64] = Array(
  repeating: 0, count: 1024 * 1024 ) } ͓Αͦ.J#ͷ༰ྔΛ֬อ 26

9DPEFͷ%FCVH/BWJHBUPS 27 1

&YFSDJTFΛλοϓ͢Δͱ   ૿͑ͨ··ݮΒͳ͍ ʢϝϞϦϦʔΫ͍ͯ͠Δʣ 28 1

9DPEFͷ%FCVH.FNPSZ(SBQI 29 2

ϝϞϦϦʔΫͷࣗಈݕ஌ʹҾ͔͔ͬͬͨ ॥؀ࢀরͷ༷ࢠΛڭ͑ͯ͘ΕΔ 30 2

*OTUSVNFOUTͷ-FBLT 31 3

ϝϞϦϦʔΫͷࣗಈݕ஌ʹҾ͔͔ͬͬͨ ૿͑ͨ··ݮ͍ͬͯͳ͍ʢϦʔΫ͍ͯ͠Δʣ 32 3

9$5"TTFSU/P-FBL 33 4

ϝϞϦϦʔΫΛݕ஌ͨ͠ 34 4

&YFSDJTF·ͱΊ %FCVH/BWJHBUPS %FCVH.FNPSZ (SBQI *OTUSVNFOUT ͷϝϞϦάϥϑ *OTUSVNFOUTͷࣗಈ ݕ஌ 9$5"TTFSU/P-FBL ✅
✅ ✅ ✅ ✅ 35

&YFSDJTF @implementation Weight2 - (id)init { if (self = [super
init]) { size_t size8MiB = 8*1024*1024; void* mem = malloc(size8MiB); if (mem == NULL) { return self; } // NOTE: Avoid memory overcommit. memset(mem, size8MiB, 1); _mem = mem; } return self; } NBMMPDͰಉ͡༰ྔͷϝϞϦΛ   ֬อ͍ͯ͠Δ 37

ΜʁͳΜ͔มΘͬͨʜ͔ʁ ʢ஫ɿಉ͡༰ྔΛϝϞϦϦʔΫͯ͠·͢ʣ 39 1

ϝϞϦϦʔΫͷࣗಈݕ஌ʹҾ͔͔ͬͬͨ ॥؀ࢀরͷ༷ࢠΛڭ͑ͯ͘ΕΔ 41 2

ϝϞϦϦʔΫͷࣗಈݕ஌ʹҾ͔͔ͬͬͨ ૿͑ͨ··ݮ͍ͬͯͳ͍ʢϦʔΫ͍ͯ͠Δʣ 43 3

&YFSDJTF·ͱΊ %FCVH/BWJHBUPS %FCVH.FNPSZ (SBQI *OTUSVNFOUT ͷϝϞϦάϥϑ *OTUSVNFOUTͷࣗಈ ݕ஌ 9$5"TTFSU/P-FBL 🤔
✅ ✅ ✅ ✅ 46 NBMMPDͰ֬อ͞ΕͨϝϞϦ͕දࣔ͞Εͳ͍

&YFSDJTF class Weight3 { private let data = Data(count: 8
* 1024 * 1024) } 48 %BUBͰಉ͡༰ྔͷϝϞϦΛ֬อ

✅ ✅ ✅ ✅ 51 %BUBͰ֬อ͞ΕͨϝϞϦ͕දࣔ͞Εͳ͍

&YFSDJTF public static func exercise2() -> Exercise2 { let x
= Exercise2() var values = [Any]() values.append(Weight2() as Any) for _ in 0..<100 { values.append(Exercise2()) } let y = Indirect() values.append(y) y.value = ["y": x] for _ in 0..<100 { values.append(Exercise2()) } x.value = values return x άϥϑͷมԽΛΘ͔Γ΍͘͢   ͢ΔͨΊͷେ͖ͳΦϒδΣΫτ ॥؀ࢀরΛ௥Ճ ແؔ܎ͳࢀরΛͨ͘͞Μ௥Ճ ແؔ܎ͳࢀরΛͨ͘͞Μ௥Ճ 52

✅ ✅ ✅ ✅ 53

&YFSDJTF public static func exercise3() -> Exercise3 { let x
= Exercise3() let y = Indirect() x.value = y var prev = y for _ in 0..<100 { let z = Indirect() prev.value = z prev = z } prev.value = x ௕େͳ॥؀ࢀরύεΛઃఆ 54

ϝϞϦϦʔΫͷࣗಈݕ஌ʹҾ͔͔ͬΒͳ͍ʂ 58 2

ϝϞϦϦʔΫͷࣗಈݕ஌ʹҾ͔͔ͬΒͳ͍ʂ ૿͑ͨ··ݮ͍ͬͯͳ͍ʢϦʔΫ͍ͯ͠Δʣ 60 3

❌ ✅ ❌ ✅ ௕େͳ॥؀ࢀর͸ݕ஌Ͱ͖ͣ ௕େͳ॥؀ࢀর͸ݕ஌Ͱ͖ͣ 63

&YFSDJTF public class Exercise4 { var value: Any? private let
weight = Weight1() init() { let x = Indirect() x.value = { _ = self } self.value = x } } Ϋϩʔδϟ͕ࣗ਎ΛڧࢀরͰ   Ωϟϓνϟͯ͠॥؀ࢀরͤ͞Δ 64

✅ ✅ ✅ ✅ 65

&YFSDJTF public static func exercise5() -> Exercise5_1 { let x
= Exercise5_1() let y = Exercise5_2.init(x) x.value = y return x } 0CKFDUJWF$ͱ4XJGUͷؒͰ   ॥؀ࢀরͤ͞Δ 66

✅ ✅ ✅ ✅ 67

&YFSDJTF public class Exercise6: EventHubObserver { private let weight =
Weight2() init() { EventHub.shared.add(observer: self) } deinit { EventHub.shared.removeObserver(observer: self) } } EFJOJUͰߪಡղআ͢Δ͜ͱΛ   ҙਤͨ͠ίʔυ͕ͩɺ   ͦ΋ͦ΋ߪಡղআ͞Εͳ͍ͱ   ࢀর͕࢒͍ͬͯͯEFJOJU͕   ૸Βͳ͍ͷͰϝϞϦϦʔΫ͢Δ 68

❌ ✅ ❌ ✅ ॥؀ࢀরͰ͸ͳ͍ͷͰݕ஌Ͱ͖ͣ ॥؀ࢀরͰ͸ͳ͍ͷͰݕ஌Ͱ͖ͣ 69

&YFSDJTF public class Exercise7 { var value: Any? private let
weight = Weight2() public class Indirect: CustomReflectable { var value: Any? public var customMirror: Mirror { return Mirror(self, children: []) } } .JSSPS SF fl FDUJOH Ͱ   Կ΋TUPSFEQSPQ͕   ͳ͍ͱࡨ֮ͤ͞Δ 70

✅ ✅ ✅ ❌ .JSSPSʹґଘ͍ͯ͠ΔͷͰ$VTUPN3F fl FDUBCMF͕   ࣮૷͞Ε͍ͯΔΦϒδΣΫτͰ͸ෆਖ਼֬ͳ݁ՌʹͳΔ 71

&YFSDJTF·ͱΊ &YFSDJTF %FCVH/BWJHBUPS %FCVH.FNPSZ (SBQI *OTUSVNFOUT ͷϝϞϦάϥϑ *OTUSVNFOUTͷ   ࣗಈݕ஌
9$5"TTFSU/P-FBL ✅ ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ❌ ✅ ❌ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ❌ ✅ ❌ ✅ 🤔 ✅ ✅ ✅ ❌ 72

9$5"TTFSU/P-FBL ✅ ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ❌ ✅ ❌ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ❌ ✅ ❌ ✅ 🤔 ✅ ✅ ✅ ❌ NBMMPDͰ֬อ͞ΕͨϝϞϦ΍%BUBͳͲͷϝϞϦ   ࢖༻ྔ͕ݟ͑ͳ͍ɻϝϞϦϦʔΫͯ͠ͳ͍Α͏ʹ   ݟ͑ͯ΋ϝϞϦϦʔΫ͍ͯ͠Δ͜ͱ͕͋Γ͏Δ 73

9$5"TTFSU/P-FBL ✅ ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ❌ ✅ ❌ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ❌ ✅ ❌ ✅ 🤔 ✅ ✅ ✅ ❌ ॥؀ࢀরύε͕௕͍৔߹΍ɺߪಡͷ   ղআ๨Ε͸ݕ஌Ͱ͖ͳ͍ɻࣗಈݕ஌Ͱ   ϝϞϦϦʔΫ͕͋ΔͱݴΘΕͨ৔߹͸   ৴༻ͯ͠ྑ͍͕ɺٯ͸ա৴ͯ͠͸͍͚ͳ͍ 74

9$5"TTFSU/P-FBL ✅ ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ❌ ✅ ❌ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ❌ ✅ ❌ ✅ 🤔 ✅ ✅ ✅ ❌ ҆ఆͯ͠ϝϞϦͷ࢖༻ྔͷ૿ݮΛ   ֬ೝͰ͖͍ͯΔɻϝϞϦϦʔΫͷ   ༗ແΛௐ΂͍ͨͳΒ·ͣ͜ΕΛݟΔ΂͖ 75

9$5"TTFSU/P-FBL ✅ ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ❌ ✅ ❌ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ❌ ✅ ❌ ✅ 🤔 ✅ ✅ ✅ ❌ ॥؀ࢀরύε͕௕͍৔߹΍ɺߪಡͷ   ղআ๨Ε͸ݕ஌Ͱ͖ͳ͍ɻࣗಈݕ஌Ͱ   ϝϞϦϦʔΫ͕͋Δͱࢦఠ͞Εͨ৔߹͸   ৴༻ͯ͠Α͍͕ɺͳ͍ͱࢦఠ͞Εͨ৔߹ ͸ա৴ͯ͠͸͍͚ͳ͍ 76

9$5"TTFSU/P-FBL ✅ ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ❌ ✅ ❌ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ✅ ✅ ✅ ✅ 🤔 ❌ ✅ ❌ ✅ 🤔 ✅ ✅ ✅ ❌ ·Εʹ$VTUPN3F fl FDUBCMFΛ࣮૷͍ͯ͠Δ   ΦϒδΣΫτ͕͋ΔͷͰ஫ҙ͕ඞཁɻ ϝϞϦϦʔΫ͕͋Δͱࢦఠ͞Εͨ৔߹͸   ৴༻Ͱ͖Δ͕ɺͳ͍ͱࢦఠ͞Εͨ৔߹͸   ա৴ͯ͠͸͍͚ͳ͍ 77

·ͱΊ wϝϞϦϦʔΫΛ୳͢ʹ͸·ͣ*OTUSVNFOUTͷ-FBLTͷ   ϝϞϦ࢖༻ྔάϥϑΛݟΔͱΑ͍ wͦΕҎ֎ͷํ๏͸ϝϞϦϦʔΫ͕͋ͬͯ΋ݟམͱ͢   Մೳੑ͕͋ΔͷͰɺ݁ՌΛա৴͠ͳ͍ํ͕Α͍ 78

実践 9 つのメモリリークどう見つける？/ How to detect 9 types of ...

実践 9 つのメモリリークどう見つける？/ How to detect 9 types of memory leaks?

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