{"id":45638,"date":"2023-08-24T04:03:22","date_gmt":"2023-02-28T11:44:35","guid":{"rendered":"https:\/\/www.silicloud.com\/zh\/blog\/45638-2\/"},"modified":"2024-04-30T19:51:22","modified_gmt":"2024-04-30T11:51:22","slug":"45638-2","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/zh\/blog\/45638-2\/","title":{"rendered":""},"content":{"rendered":"<p>\u672c\u8a18\u4e8b\u3067\u306f\uff0crustc\u304c\u751f\u6210\u3059\u308b\u30b3\u30fc\u30c9\u306b\u3064\u3044\u3066\u306e\u8abf\u67fb\u3092\u884c\u3063\u3066\u3044\u307e\u3059\uff0e<\/p>\n<p>\u8a18\u4e8b\u306f\u968f\u6642\u66f4\u65b0\u3055\u308c\u307e\u3059\uff0e<\/p>\n<p>\u6700\u521d\u306e\u8a18\u4e8b\u3092\u66f8\u3044\u305f\u6642\u70b9\u3067\uff0cRust Playground\u3067\u4f7f\u7528\u3055\u308c\u3066\u3044\u305frustc\u306e\u30d0\u30fc\u30b8\u30e7\u30f3\u306f\u4ee5\u4e0b\u306e\u901a\u308a\u3067\u3059\uff0e<\/p>\n<ul class=\"post-ul\">\n<li style=\"list-style-type: none;\">\n<ul class=\"post-ul\">Stable: 1.29.2<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<ul class=\"post-ul\">\n<li style=\"list-style-type: none;\">\n<ul class=\"post-ul\">Beta: 1.30.0-beta.15 (590121930fc942315c84)<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<ul class=\"post-ul\">Nightly: 1.31.0-nightly (14f42a732ff9562fb5f0)<\/ul>\n<h1>String::from()<\/h1>\n<p>Rust Playground<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">fn<\/span> <span class=\"nf\">main<\/span><span class=\"p\">()<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"k\">let<\/span> <span class=\"n\">s<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">String<\/span><span class=\"p\">::<\/span><span class=\"nf\">from<\/span><span class=\"p\">(<\/span><span class=\"s\">\"world!\"<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"nd\">println!<\/span><span class=\"p\">(<\/span><span class=\"s\">\"Hello, {}\"<\/span><span class=\"p\">,<\/span> <span class=\"n\">s<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<p>String\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306f\uff0c\u30d2\u30fc\u30d7\u3067\u306f\u306a\u304f\u30b9\u30bf\u30c3\u30af\u4e0a\u306b\u78ba\u4fdd\u3055\u308c\u307e\u3059\uff0e\u6587\u5b57\u5217\u3092\u683c\u7d0d\u3059\u308b\u305f\u3081\u306e\u9818\u57df\u306f\uff0c\u30d2\u30fc\u30d7\u304b\u3089\u5272\u308a\u5f53\u3066\u3089\u308c\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code>  <span class=\"nv\">%s<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"p\">...<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@\"_ZN87_$LT$alloc..string..String$u20$as$u20$core..convert..From$LT$$RF$$u27$a$u20$str$GT$$GT$4from17h0e73539cabf31215E\"<\/span><span class=\"p\">(<\/span><span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">*<\/span> <span class=\"k\">noalias<\/span> <span class=\"k\">nocapture<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">sret<\/span> <span class=\"k\">dereferenceable<\/span><span class=\"p\">(<\/span><span class=\"m\">24<\/span><span class=\"p\">)<\/span> <span class=\"nv\">%s<\/span><span class=\"p\">,<\/span> <span class=\"p\">[<\/span><span class=\"m\">0<\/span> <span class=\"p\">x<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">]*<\/span> <span class=\"k\">noalias<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">readonly<\/span> <span class=\"k\">bitcast<\/span> <span class=\"p\">(&lt;{<\/span> <span class=\"p\">[<\/span><span class=\"m\">6<\/span> <span class=\"p\">x<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">]<\/span> <span class=\"p\">}&gt;*<\/span> <span class=\"vg\">@byte_str.1<\/span> <span class=\"k\">to<\/span> <span class=\"p\">[<\/span><span class=\"m\">0<\/span> <span class=\"p\">x<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">]*),<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">6<\/span><span class=\"p\">)<\/span>\r\n<\/code><\/pre>\n<h2>Mutability<\/h2>\n<p>\u8a18\u4e8b\u306e\u8da3\u65e8\u304b\u3089\u306f\u5916\u308c\u3066\u3057\u307e\u3044\u307e\u3059\u304c\uff0c\u5909\u6570\u306e\u30df\u30e5\u30fc\u30bf\u30d3\u30ea\u30c6\u30a3\u306b\u3064\u3044\u3066\u8a00\u53ca\u3057\u3066\u304a\u304d\u307e\u3059\uff0e<\/p>\n<p>\u4e00\u822c\u306b\uff0c\u3042\u308b\u5909\u6570\u306b\u3064\u3044\u3066immutable\u3067\u3042\u308b\u3068\u8a00\u3063\u305f\u5834\u5408\uff0c\u4ee5\u4e0b\u306e\uff12\u3064\u306e\u3069\u3061\u3089\u304b\uff0c\u307e\u305f\u306f\u4e21\u65b9\u3092\u610f\u5473\u3059\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\uff0e<\/p>\n<ol>\n<li style=\"list-style-type: none;\">\n<ol>\u5909\u6570\u306b\u306f\uff11\u5ea6\u3057\u304b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u30d0\u30a4\u30f3\u30c9\u3067\u304d\u306a\u3044\uff08C\/C++\u306echar* const\u306b\u76f8\u5f53\uff09<\/ol>\n<\/li>\n<\/ol>\n<p>&nbsp;<\/p>\n<ol>\u5909\u6570\u306b\u30d0\u30a4\u30f3\u30c9\u3055\u308c\u305f\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u66f8\u304d\u63db\u3048\u308b\u3053\u3068\u304c\u3067\u304d\u306a\u3044\uff08C\/C++\u306econst char*\u306b\u76f8\u5f53\uff09<\/ol>\n<p>\u4f8b\u3048\u3070\u5148\u7a0b\u306e\u4f8b\u3067\u8003\u3048\u308b\u3068\uff0c\u4ee5\u4e0b\u306e\u6587\u306f<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">let<\/span> <span class=\"n\">s<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">String<\/span><span class=\"p\">::<\/span><span class=\"nf\">from<\/span><span class=\"p\">(<\/span><span class=\"s\">\"world!\"<\/span><span class=\"p\">);<\/span>\r\n<\/code><\/pre>\n<p>s\u306b\u306f\u4e00\u5ea6\u3057\u304b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u30d0\u30a4\u30f3\u30c9\u3067\u304d\u306a\u3044<\/p>\n<p>s\u306b\u30d0\u30a4\u30f3\u30c9\u3055\u308c\u308bString\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u66f8\u304d\u63db\u3048\u308b\u3053\u3068\u304c\u3067\u304d\u306a\u3044<\/p>\n<p>\u3068\u3044\u3046\u3053\u3068\u3092\u610f\u5473\u3057\u307e\u3059\uff0e\u305d\u306e\u305f\u3081\uff0c\u5f8c\u8005\u306e\u5236\u7d04\u306e\u307f\u304c\u5fc5\u8981\u306a\u5834\u5408\u306f\uff0clet\u3067s\u3092\u518d\u5b9a\u7fa9\u3059\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\uff08\u5225\u306e\u578b\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u4f7f\u7528\u3057\u3066\u3044\u308b\u5834\u5408\u306f\uff0c\u518d\u5b9a\u7fa9\u304c\u4e0d\u8981\u306a\u5834\u5408\u304c\u3042\u308b\u304b\u3082\u3057\u308c\u307e\u305b\u3093\uff09\uff0e<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">let<\/span> <span class=\"n\">s<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">String<\/span><span class=\"p\">::<\/span><span class=\"nf\">from<\/span><span class=\"p\">(<\/span><span class=\"s\">\"foo\"<\/span><span class=\"p\">);<\/span>\r\n<span class=\"c\">\/\/ s(\"foo\")\u306b\u5bfe\u3059\u308b\u51e6\u7406\u3092\u5b9f\u884c<\/span>\r\n\r\n<span class=\"k\">let<\/span> <span class=\"n\">s<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">String<\/span><span class=\"p\">::<\/span><span class=\"nf\">from<\/span><span class=\"p\">(<\/span><span class=\"s\">\"bar\"<\/span><span class=\"p\">);<\/span>  <span class=\"c\">\/\/ s\u3092\u518d\u5b9a\u7fa9\uff08\u30eb\u30fc\u30d7\u5185\u306e\u51e6\u7406\u306a\u3069\u3067\u3053\u306e\u3088\u3046\u306b\u66f8\u304f\u3053\u3068\u304c\u591a\u3044\u3068\u601d\u3044\u307e\u3059\uff09<\/span>\r\n<\/code><\/pre>\n<p>\u305f\u3060\uff0cRust\u306e\u5909\u6570\u306emutability\u3092\uff0c\u30b9\u30bf\u30c3\u30af\u4e0a\u306b\u78ba\u4fdd\u3055\u308c\u305f\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\uff08\u30e1\u30e2\u30ea\u9818\u57df\uff09\u306b\u95a2\u3059\u308b\u3082\u306e\u3060\u3068\u89e3\u91c8\u3059\u3079\u304d\u3067\u306f\u306a\u3044\u3068\u8003\u3048\u307e\u3059\uff0e\u305d\u306e\u3088\u3046\u306b\u89e3\u91c8\u3059\u308b\u3053\u3068\u3067\u3082<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">let<\/span> <span class=\"n\">s<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">String<\/span><span class=\"p\">::<\/span><span class=\"nf\">from<\/span><span class=\"p\">(<\/span><span class=\"s\">\"world\"<\/span><span class=\"p\">);<\/span>  <span class=\"c\">\/\/ \u30b9\u30bf\u30c3\u30af\u4e0a\u306b`String`\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u914d\u7f6e\u3057\uff0c\u305d\u308c\u306fimmutable<\/span>\r\n<span class=\"n\">s<\/span><span class=\"nf\">.push<\/span><span class=\"p\">(<\/span><span class=\"sc\">'!'<\/span><span class=\"p\">);<\/span>  <span class=\"c\">\/\/ \u9577\u3055\u306b\u95a2\u3059\u308b\u30d5\u30a3\u30fc\u30eb\u30c9\u304c\u30b9\u30bf\u30c3\u30af\u4e0a\u306b\u5b58\u5728\u3059\u308b\u304c\uff0c\u305d\u306e\u9818\u57df\u306f\u66f8\u304d\u63db\u3048\u3089\u308c\u306a\u3044<\/span>\r\n<\/code><\/pre>\n<p>\u304c\u30b3\u30f3\u30d1\u30a4\u30eb\u30a8\u30e9\u30fc\u3068\u306a\u308b\u3053\u3068\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u304c\u53ef\u80fd\u3067\u3059\uff0e\u3057\u304b\u3057\uff0c\u4f8b\u3048\u3070String::from()\u304c\u300cString\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u30d2\u30fc\u30d7\u4e0a\u306b\u914d\u7f6e\u3057\uff0c\u305d\u306e\u30a2\u30c9\u30ec\u30b9\u3092\u30b9\u30bf\u30c3\u30af\u4e0a\u306b\u78ba\u4fdd\u3055\u308c\u305f\u30d0\u30a4\u30f3\u30c9\u5148\u5909\u6570\u306e\u305f\u3081\u306e\u30e1\u30e2\u30ea\u9818\u57df\u306b\u66f8\u304d\u8fbc\u3080\u300d\u3068\u3044\u3046\u5b9f\u88c5\u306b\u306a\u3063\u3066\u3044\u305f\u3068\u3059\u308b\u3068\uff0c\u4e0a\u8a18\u306e\u3088\u3046\u306b\u89e3\u91c8\u3059\u308b\u3053\u3068\u304c\u3067\u304d\u306a\u304f\u306a\u308a\u307e\u3059\uff0e<\/p>\n<p>\u305d\u306e\u305f\u3081\uff0cpush()\u304c\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u5b9a\u7fa9\u3055\u308c\u3066\u3044\u308b\u305f\u3081\u30b3\u30f3\u30d1\u30a4\u30eb\u30a8\u30e9\u30fc\u306b\u306a\u308b\u3068\u89e3\u91c8\u3059\u3079\u304d\u3067\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">pub<\/span> <span class=\"k\">fn<\/span> <span class=\"nf\">push<\/span><span class=\"p\">(<\/span><span class=\"o\">&amp;<\/span><span class=\"k\">mut<\/span> <span class=\"k\">self<\/span><span class=\"p\">,<\/span> <span class=\"n\">ch<\/span><span class=\"p\">:<\/span> <span class=\"nb\">char<\/span><span class=\"p\">)<\/span> <span class=\"p\">{}<\/span>  <span class=\"c\">\/\/ self\u306e\u578b\u306f&amp;mut String<\/span>\r\n<\/code><\/pre>\n<p>\u578b\u306b\u5bfe\u3059\u308b\u5236\u7d04\u306f\uff0c\u305d\u306e\u578b\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c\u3069\u306e\u3088\u3046\u306b\u5b9f\u88c5\u3055\u308c\u3066\u3044\u308b\u306e\u304b\uff08\u4eca\u306e\u4f8b\u3060\u3068\uff0cString\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c\u30b9\u30bf\u30c3\u30af\u4e0a\u306b\u78ba\u4fdd\u3055\u308c\u308b\u306e\u304b\uff0c\u30d2\u30fc\u30d7\u4e0a\u306b\u78ba\u4fdd\u3055\u308c\u305d\u306e\u30a2\u30c9\u30ec\u30b9\u306e\u307f\u304c\u30b9\u30bf\u30c3\u30af\u4e0a\u306e\u5909\u6570\u306b\u4fdd\u5b58\u3055\u308c\u308b\u306e\u304b\uff0c\u306a\u3069\uff09\u306a\u3069\u306e\u8a73\u7d30\u306b\u95a2\u308f\u3089\u306a\u3044\u62bd\u8c61\u7684\u306a\u6982\u5ff5\u3067\u3042\u308a\uff0cRust\u306b\u304a\u3051\u308bmutability\u3068\u306f\u578b\u306b\u5bfe\u3059\u308b\u5236\u7d04\u3092\u610f\u5473\u3057\u3066\u3044\u308b\u3068\u8003\u3048\u308b\u3079\u304d\u3067\u3059\uff0e<\/p>\n<p>\u3061\u306a\u307f\u306b\uff0cTRPL First Edition\u306b\u306f\u4e0a\u8a18\u306b\u95a2\u9023\u3059\u308b\u8a18\u8ff0\u304c\uff13\u7ae0\u3067\u51fa\u3066\u304d\u307e\u3059\u304c\uff0c\u65b0\u3057\u3044TRPL\u3067\u306f\u300cexterior mutability\u300d\u306b\u95a2\u3059\u308b\u8a18\u8ff0\u306f\u306a\u304f\u306a\u3063\u3066\u3044\u307e\u3059\uff08\u300cinterior mutability\u300d\u306f\uff11\uff15\u7ae0\u3067\u51fa\u3066\u304d\u307e\u3059\uff09\uff0e\u524a\u9664\u3057\u305f\u7406\u7531\u306f\u4e0d\u660e\u3067\u3059\u304c\uff08GitHub\u306e\u5c65\u6b74\u3092\u898b\u308c\u3070\u78ba\u8a8d\u3067\u304d\u305d\u3046\u3067\u3059\u304c\uff09\uff0c\u91cd\u8981\u306a\u6982\u5ff5\u306a\u306e\u3067\uff13\u7ae0\u3067\u8aac\u660e\u3057\u3066\u304a\u3044\u305f\u307b\u3046\u304c\u826f\u3044\u3088\u3046\u306a\u6c17\u304c\u3057\u307e\u3059\uff0e<\/p>\n<h1>String\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u6240\u6709\u6a29\u306e\u79fb\u52d5<\/h1>\n<p>Rust Playground<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">fn<\/span> <span class=\"nf\">main<\/span><span class=\"p\">()<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"k\">let<\/span> <span class=\"n\">s1<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">String<\/span><span class=\"p\">::<\/span><span class=\"nf\">from<\/span><span class=\"p\">(<\/span><span class=\"s\">\"world!\"<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"nf\">hello<\/span><span class=\"p\">(<\/span><span class=\"n\">s1<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"k\">fn<\/span> <span class=\"nf\">hello<\/span><span class=\"p\">(<\/span><span class=\"n\">s<\/span><span class=\"p\">:<\/span> <span class=\"nb\">String<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"nd\">println!<\/span><span class=\"p\">(<\/span><span class=\"s\">\"hello, {}\"<\/span><span class=\"p\">,<\/span> <span class=\"n\">s<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<p>\u6240\u6709\u6a29\u304c\u79fb\u52d5\u3057\uff0chello(s1)\u4ee5\u964d\u306bs1\u3092\u4f7f\u7528\u3059\u308b\u3068\u30b3\u30f3\u30d1\u30a4\u30eb\u30a8\u30e9\u30fc\u3068\u306a\u308a\u307e\u3059\uff0e\u305d\u306e\u305f\u3081\uff0cs\u3068s1\u306f\u30b9\u30bf\u30c3\u30af\u4e0a\u306e\u540c\u4e00String\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u4f7f\u7528\u3059\u308b\u3088\u3046\u306a\u6700\u9069\u5316\u304c\u884c\u308f\u308c\u308b\u3053\u3068\u3092\u671f\u5f85\u3057\u3066\u3044\u305f\u306e\u3067\u3059\u304c\uff0c\u5b9f\u969b\u306fhello()\u547c\u3073\u51fa\u3057\u524d\u306b\u30b3\u30d4\u30fc\u304c\u767a\u751f\u3057\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code>  <span class=\"nv\">%_3<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"nv\">%s1<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"nv\">%0<\/span> <span class=\"p\">=<\/span> <span class=\"k\">bitcast<\/span> <span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">*<\/span> <span class=\"nv\">%s1<\/span> <span class=\"k\">to<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span>\r\n  <span class=\"p\">...<\/span>\r\n  <span class=\"nv\">%1<\/span> <span class=\"p\">=<\/span> <span class=\"k\">bitcast<\/span> <span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">*<\/span> <span class=\"nv\">%_3<\/span> <span class=\"k\">to<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@llvm.lifetime.start.p0i8<\/span><span class=\"p\">(<\/span><span class=\"kt\">i64<\/span> <span class=\"m\">24<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"k\">nonnull<\/span> <span class=\"nv\">%1<\/span><span class=\"p\">)<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@llvm.memcpy.p0i8.p0i8.i64<\/span><span class=\"p\">(<\/span><span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span> <span class=\"nv\">%1<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span> <span class=\"nv\">%0<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">24<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i1<\/span> <span class=\"k\">false<\/span><span class=\"p\">)<\/span>\r\n<\/code><\/pre>\n<p>\u30a2\u30bb\u30f3\u30d6\u30ea\u30b3\u30fc\u30c9\u3067\u3082\u30b3\u30d4\u30fc\u304c\u78ba\u8a8d\u3067\u304d\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code>playground::main:\r\n    pushq   %rbx\r\n    subq    $112, %rsp\r\n    leaq    .Lbyte_str.1(%rip), %rsi\r\n    leaq    88(%rsp), %rdi\r\n    movl    $6, %edx\r\n    callq   &lt;alloc::string::String as core::convert::From&lt;&amp;'a str&gt;&gt;::from@PLT\r\n    movq    104(%rsp), %rax\r\n    movq    %rax, 16(%rsp)\r\n    movups  88(%rsp), %xmm0\r\n    movaps  %xmm0, (%rsp)\r\n<\/code><\/pre>\n<p>Nightly Version\u3067\u30b3\u30f3\u30d1\u30a4\u30eb\u3059\u308b\u3068\uff0cString\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u30b3\u30d4\u30fc\u3059\u308b\u30b3\u30fc\u30c9\u304c\u306a\u304f\u306a\u308b\u306e\u3067\uff0c\u6539\u5584\u3055\u308c\u305f\u306e\u304b\u3082\u3057\u308c\u307e\u305b\u3093\uff0e<\/p>\n<h1>String\u30aa\u30d6\u30b8\u30a7\u30af\u306e\u501f\u7528<\/h1>\n<p>Rust Playground<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">fn<\/span> <span class=\"nf\">main<\/span><span class=\"p\">()<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"k\">let<\/span> <span class=\"n\">s1<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">String<\/span><span class=\"p\">::<\/span><span class=\"nf\">from<\/span><span class=\"p\">(<\/span><span class=\"s\">\"world!\"<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"nf\">hello<\/span><span class=\"p\">(<\/span><span class=\"o\">&amp;<\/span><span class=\"n\">s1<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"k\">fn<\/span> <span class=\"nf\">hello<\/span><span class=\"p\">(<\/span><span class=\"n\">s<\/span><span class=\"p\">:<\/span> <span class=\"o\">&amp;<\/span><span class=\"nb\">String<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"nd\">println!<\/span><span class=\"p\">(<\/span><span class=\"s\">\"Hello, {}\"<\/span><span class=\"p\">,<\/span> <span class=\"n\">s<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<p>String\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u501f\u7528\u3059\u308b\u3088\u3046\u306b\u5909\u66f4\u3059\u308b\u3068\uff0c\u30b3\u30d4\u30fc\u3057\u306a\u304f\u306a\u308a\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code>  <span class=\"nv\">%s1<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"nv\">%0<\/span> <span class=\"p\">=<\/span> <span class=\"k\">bitcast<\/span> <span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">*<\/span> <span class=\"nv\">%s1<\/span> <span class=\"k\">to<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span>\r\n  <span class=\"p\">...<\/span>\r\n<\/code><\/pre>\n<p>\u6240\u6709\u6a29\u304c\u79fb\u52d5\u3059\u308b\u5834\u5408\u306b\u5b58\u5728\u3057\u305f%_3\u3084llvm.memcpy\u306f\u306a\u304f\u306a\u3063\u3066\u3044\u307e\u3059\uff0e<\/p>\n<p>fmt()\u306e\u5f15\u6570\u306e\u578b\u304c%&#8221;alloc::string::String&#8221;**\u306b\u306a\u3063\u3066\u3044\u308b\u70b9\u304c\u6c17\u306b\u306a\u308a\u307e\u3059\uff0e\u6240\u6709\u6a29\u304c\u79fb\u52d5\u3059\u308b\u5834\u5408\u306f%&#8221;alloc::string::String&#8221;*\u3067\u3057\u305f\uff0e<\/p>\n<p>%&#8221;alloc::string::String&#8221;**\u3068\u306a\u3063\u3066\u3044\u308b\u305f\u3081\uff0c\u6240\u6709\u6a29\u304c\u79fb\u52d5\u3059\u308b\u5834\u5408\u306e\u30b3\u30fc\u30c9\u3068\u6bd4\u3079\u3066\uff0c\u30a2\u30c9\u30ec\u30b9\u53c2\u7167\u304c\uff11\u56de\u5897\u3048\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code>&lt;&amp;'a T as core::fmt::Display&gt;::fmt:\r\n    movq    %rsi, %rax\r\n    movq    (%rdi), %rcx\r\n    movq    (%rcx), %rdi\r\n    movq    16(%rcx), %rsi\r\n    movq    %rax, %rdx\r\n    jmp &lt;str as core::fmt::Display&gt;::fmt@PLT\r\n<\/code><\/pre>\n<p>LLVM IR\u306e\u30c7\u30d0\u30c3\u30b0\u30d3\u30eb\u30c9\u306ehello()\u3092\u78ba\u8a8d\u3057\u307e\u3057\u305f\u304c\uff0c\u5f15\u6570\u306e\u578b\u306f\u4e88\u60f3\u901a\u308a%&#8221;alloc::string::String&#8221;*\u3068\u306a\u3063\u3066\u3044\u307e\u3057\u305f\uff0e\u3057\u304b\u3057\uff0c\u76f4\u63a5\u5f15\u6570\u3092\u4f7f\u7528\u3059\u308b\u306e\u3067\u306f\u306a\u304f\uff0c\u30b9\u30bf\u30c3\u30af\u4e0a\u306b%&#8221;alloc::string::String&#8221;*\u3092\u683c\u7d0d\u3059\u308b\u305f\u3081\u306e\u9818\u57df\u3092\u78ba\u4fdd\u3057\u5024\u3092\u30b3\u30d4\u30fc\u3057\u3066\u3044\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code><span class=\"c1\">; playground::hello<\/span>\r\n<span class=\"c1\">; Function Attrs: uwtable<\/span>\r\n<span class=\"k\">define<\/span> <span class=\"k\">internal<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@_ZN10playground5hello17hb8df0bc2cde9eedcE<\/span><span class=\"p\">(<\/span><span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">*<\/span> <span class=\"k\">noalias<\/span> <span class=\"k\">readonly<\/span> <span class=\"k\">dereferenceable<\/span><span class=\"p\">(<\/span><span class=\"m\">24<\/span><span class=\"p\">))<\/span> <span class=\"k\">unnamed_addr<\/span> <span class=\"vg\">#0<\/span> <span class=\"nv\">!dbg<\/span> <span class=\"nv\">!749<\/span> <span class=\"p\">{<\/span>\r\n<span class=\"nl\">start:<\/span>\r\n  <span class=\"nv\">%arg0<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">**,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"nv\">%_11<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"kt\">i64<\/span><span class=\"p\">*,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"nv\">%_10<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"p\">[<\/span><span class=\"m\">1<\/span> <span class=\"p\">x<\/span> <span class=\"p\">{<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*,<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"p\">}],<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"nv\">%_3<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"nv\">%\"core::fmt::Arguments\"<\/span><span class=\"p\">,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"nv\">%s<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">*,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"k\">store<\/span> <span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">*<\/span> <span class=\"nv\">%0<\/span><span class=\"p\">,<\/span> <span class=\"nv\">%\"alloc::string::String\"<\/span><span class=\"p\">**<\/span> <span class=\"nv\">%s<\/span><span class=\"p\">,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n<\/code><\/pre>\n<p>\u308f\u3056\u308f\u3056\u3053\u306e\u3088\u3046\u306b\u3059\u308b\u7406\u7531\u304c\u79c1\u306b\u306f\u601d\u3044\u3064\u304d\u307e\u305b\u3093\uff0e\u3082\u3057\u7406\u7531\u304c\u5206\u304b\u308b\u4eba\u304c\u3044\u305f\u3089\u6559\u3048\u3066\u304f\u3060\u3055\u3044\uff0e @lo48576\u3055\u3093\u306b\u6559\u3048\u3066\u3044\u305f\u3060\u304d\u307e\u3057\u305f\uff0eprintln!()\u306f\u51fa\u529b\u5bfe\u8c61\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u501f\u7528\u3059\u308b\u305f\u3081\uff0c&amp;&amp;String\u3068\u306a\u308b\u305f\u3081\u3067\u3059\uff0e<\/p>\n<h1>Array and Vec<\/h1>\n<p>Rust\u3067\u30d7\u30ed\u30b0\u30e9\u30e0\u3092\u66f8\u3044\u3066\u3044\u308b\u65b9\u306f\u77e5\u3063\u3066\u3044\u308b\u3053\u3068\u3060\u3068\u601d\u308f\u308c\u307e\u3059\u304c\uff0cArray\u306f\u30b9\u30bf\u30c3\u30af\u4e0a\u306b\uff08\u3082\u3057\u304f\u306ftext\u307e\u305f\u306fdata\u30bb\u30af\u30b7\u30e7\u30f3\uff09\uff0cVec\u306f\u30d2\u30fc\u30d7\u4e0a\u306b\u8981\u7d20\u3092\u914d\u7f6e\u3057\u307e\u3059\uff0e<\/p>\n<p>C++\u306estd::vector\u306f\uff0c\u8981\u7d20\u3092\u30b9\u30bf\u30c3\u30af\u4e0a\u306b\u914d\u7f6e\u3059\u308b\u3088\u3046\u306b\u30b3\u30f3\u30d1\u30a4\u30eb\u3055\u308c\u308b\u5834\u5408\u304c\u3042\u308b\u3088\u3046\u3067\u3059\u304c\uff0cVec\u306f\u5fc5\u305a\u30d2\u30fc\u30d7\u4e0a\u306b\u8981\u7d20\u3092\u914d\u7f6e\u3057\u307e\u3059\uff0e<\/p>\n<p>Rust Playground<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">fn<\/span> <span class=\"nf\">main<\/span><span class=\"p\">()<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"k\">let<\/span> <span class=\"n\">v<\/span> <span class=\"o\">=<\/span> <span class=\"nd\">vec!<\/span><span class=\"p\">[<\/span><span class=\"mi\">1<\/span><span class=\"p\">,<\/span> <span class=\"mi\">2<\/span><span class=\"p\">,<\/span> <span class=\"mi\">3<\/span><span class=\"p\">,<\/span> <span class=\"mi\">4<\/span><span class=\"p\">];<\/span>\r\n    <span class=\"k\">for<\/span> <span class=\"n\">i<\/span> <span class=\"n\">in<\/span> <span class=\"n\">v<\/span> <span class=\"p\">{<\/span>\r\n        <span class=\"nd\">println!<\/span><span class=\"p\">(<\/span><span class=\"s\">\"{}\"<\/span><span class=\"p\">,<\/span> <span class=\"n\">i<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"p\">}<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<pre class=\"post-pre\"><code>playground::main:\r\n        ...\r\n        callq __rust_alloc@PLT\r\n        ...\r\n<\/code><\/pre>\n<p>rustc\u5185\u306b\u306f\u660e\u78ba\u306a\u57fa\u6e96\u304c\u5b58\u5728\u3059\u308b\u306e\u3060\u3068\u601d\u3044\u307e\u3059\u304c\uff0c\u30d6\u30ed\u30c3\u30af\u5185\u306e\u6587\uff08\u307e\u305f\u306f\u5f0f\uff09\u304c\u5c11\u306a\u304f\uff0c\u8981\u7d20\u6570\u3082\u5c0f\u3055\u3044\u5834\u5408\u306f\uff0c\u30eb\u30fc\u30d7\u3092\u5c55\u958b\u3059\u308b\u3088\u3046\u3067\u3059\uff0e\u5b9a\u6570\u30c6\u30fc\u30d6\u30eb\u3082\u4f5c\u6210\u3055\u308c\u3066\u3044\u308b\u3088\u3046\u306a\u306e\u3067\uff0c\u3082\u3046\u3053\u3053\u307e\u3067\u3084\u3063\u305f\u3089__rust_alloc\u3082\u6d88\u305b\u308b\u3093\u3058\u3083\u306a\u3044\u304b\u3068\u601d\u3063\u3066\u3057\u307e\u3046\u306e\u3067\u3059\u304c\uff0c\u591a\u5206\u79c1\u304c\u6c17\u4ed8\u3044\u3066\u3044\u306a\u3044\u3060\u3051\u3067\u6d88\u305b\u306a\u3044\u7406\u7531\u304c\u3042\u308b\u306e\u3067\u3057\u3087\u3046\uff0e<\/p>\n<p>\u4f59\u8ac7\u3067\u3059\u304c\uff0cString\u306fVec\u3067\u5b9f\u88c5\u3055\u308c\u3066\u3044\u308b\u306e\u3067\uff0c\u6587\u5b57\u5217\u306f\u5fc5\u305a\u30d2\u30fc\u30d7\u4e0a\u306b\u914d\u7f6e\u3055\u308c\u307e\u3059\uff0eC++\u306estd::string\u306fstd::vector\u3068\u540c\u69d8\u306b\u5c0f\u3055\u3044\u6587\u5b57\u5217\u306f\u30b9\u30bf\u30c3\u30af\u4e0a\u306b\u914d\u7f6e\u3057\u307e\u3059\u304c\uff0cString\u3067\u306f\u305d\u306e\u3088\u3046\u306a\u3053\u3068\u306f\u8d77\u3053\u308a\u307e\u305b\u3093\uff0e\u30d2\u30fc\u30d7\u306b\u914d\u7f6e\u3057\u305f\u304f\u306a\u3044\u5834\u5408\u306f\uff0c\u30b9\u30e9\u30a4\u30b9\u3092\u4f7f\u3046\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\uff0e<\/p>\n<h1>Box\u3068\u30c8\u30ec\u30a4\u30c8\u30aa\u30d6\u30b8\u30a7\u30af\u30c8<\/h1>\n<p>\u3042\u308b\u30c8\u30ec\u30a4\u30c8\u3092\u5b9f\u88c5\u3059\u308b\u578b\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092Box::new()\u3067\u30d2\u30fc\u30d7\u4e0a\u306b\u78ba\u4fdd\u3057\uff0cBox&lt;\u578b&gt;\u306e\u5909\u6570\u306b\u675f\u7e1b\u3059\u308b\u3053\u3068\u3092\u8003\u3048\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">trait<\/span> <span class=\"n\">Shape<\/span> <span class=\"p\">{}<\/span>\r\n<span class=\"k\">struct<\/span> <span class=\"n\">Rectangle<\/span> <span class=\"p\">{<\/span> <span class=\"n\">width<\/span><span class=\"p\">:<\/span> <span class=\"nb\">u32<\/span><span class=\"p\">,<\/span> <span class=\"n\">height<\/span><span class=\"p\">:<\/span> <span class=\"nb\">u32<\/span> <span class=\"p\">}<\/span>\r\n<span class=\"k\">impl<\/span> <span class=\"n\">Shape<\/span> <span class=\"k\">for<\/span> <span class=\"n\">Rectangle<\/span> <span class=\"p\">{}<\/span>\r\n\r\n<span class=\"k\">let<\/span> <span class=\"n\">rect<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">Box<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"nn\">Rectangle<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"mi\">10<\/span><span class=\"p\">,<\/span> <span class=\"mi\">10<\/span><span class=\"p\">));<\/span>\r\n<\/code><\/pre>\n<p>\u5909\u6570rect\u306fBox\u578b\u3067\uff0c\u30b3\u30f3\u30d1\u30a4\u30eb\u5f8c\u306f\u30dd\u30a4\u30f3\u30bf\u30fc\u3068\u306a\u308a\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code><span class=\"c1\">; \u7c21\u5358\u306a\u30b3\u30fc\u30c9\u3060\u3068\u6700\u9069\u5316\u3067\u6d88\u3048\u3066\u3057\u307e\u3046\u306e\u3067\uff0c\u30c7\u30d0\u30c3\u30b0\u30d3\u30eb\u30c9\u3067\u78ba\u8a8d\u3057\u3066\u304f\u3060\u3055\u3044<\/span>\r\n  <span class=\"nv\">%rect<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"p\">{<\/span> <span class=\"kt\">i32<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i32<\/span> <span class=\"p\">}*,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n<\/code><\/pre>\n<p>\u3067\u306f\uff0c\u4ee5\u4e0b\u306e\u3088\u3046\u306bBox&lt;\u30c8\u30ec\u30a4\u30c8&gt;\u306e\u5909\u6570\u306b\u675f\u7e1b\u3057\u305f\u5834\u5408\u306f\u3069\u3046\u306a\u308b\u3068\u601d\u3044\u307e\u3059\u304b\uff1f<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">trait<\/span> <span class=\"n\">Shape<\/span> <span class=\"p\">{}<\/span>\r\n<span class=\"k\">struct<\/span> <span class=\"n\">Rectangle<\/span> <span class=\"p\">{<\/span> <span class=\"n\">width<\/span><span class=\"p\">:<\/span> <span class=\"nb\">u32<\/span><span class=\"p\">,<\/span> <span class=\"n\">height<\/span><span class=\"p\">:<\/span> <span class=\"nb\">u32<\/span> <span class=\"p\">}<\/span>\r\n<span class=\"k\">impl<\/span> <span class=\"n\">Shape<\/span> <span class=\"k\">for<\/span> <span class=\"n\">Rectangle<\/span> <span class=\"p\">{}<\/span>\r\n\r\n<span class=\"k\">let<\/span> <span class=\"n\">shape<\/span><span class=\"p\">:<\/span> <span class=\"nb\">Box<\/span><span class=\"o\">&lt;<\/span><span class=\"n\">Shape<\/span><span class=\"o\">&gt;<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">Box<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"nn\">Rectangle<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"mi\">10<\/span><span class=\"p\">,<\/span> <span class=\"mi\">10<\/span><span class=\"p\">));<\/span>\r\n<\/code><\/pre>\n<p>\u7d20\u76f4\u306b\u8003\u3048\u308b\u3068\u30c8\u30ec\u30a4\u30c8\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3078\u306e\u30dd\u30a4\u30f3\u30bf\u30fc\u306b\u306a\u308a\u305d\u3046\u3067\u3059\u304c\uff0c\u30c8\u30ec\u30a4\u30c8\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u305d\u306e\u3082\u306e\u306b\u306a\u308a\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code>  <span class=\"nv\">%shape<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"p\">{<\/span> <span class=\"p\">{}*,<\/span> <span class=\"p\">[<\/span><span class=\"m\">3<\/span> <span class=\"p\">x<\/span> <span class=\"kt\">i64<\/span><span class=\"p\">]*<\/span> <span class=\"p\">},<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n<\/code><\/pre>\n<p>\u30ea\u30ea\u30fc\u30b9\u30d3\u30eb\u30c9\u3067\u3082\u540c\u3058\u7d50\u679c\u306b\u306a\u308a\u307e\u3059\uff0eNightly\u3067\u3082\u540c\u3058\u3067\u3057\u305f\uff0e<\/p>\n<p>\uff11\u3064\u306e\u30dd\u30a4\u30f3\u30bf\u30fc\u306b\u30b3\u30f3\u30d1\u30a4\u30eb\u3055\u308c\u308b\u3053\u3068\u3092\u671f\u5f85\u3057\u3066Box&lt;\u30c8\u30ec\u30a4\u30c8&gt;\u578b\u3092\u4f7f\u3063\u3066\u3044\u308b\u5834\u5408\uff0c\u4ee5\u4e0b\u306e\u70b9\u306b\u6ce8\u610f\u304c\u5fc5\u8981\u3067\u3059\uff0e<\/p>\n<ul class=\"post-ul\">\n<li style=\"list-style-type: none;\">\n<ul class=\"post-ul\">\u30c7\u30fc\u30bf\u30b5\u30a4\u30ba\u304c\u4e88\u60f3\u3088\u308a\u30dd\u30a4\u30f3\u30bf\u30fc\uff11\u3064\u5206\u3060\u3051\u5927\u304d\u304f\u306a\u3063\u3066\u3044\u308b<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<ul class=\"post-ul\">\u30a2\u30c9\u30ec\u30b9\u53c2\u7167\u56de\u6570\u304c\u4e88\u60f3\u3088\u308a\uff11\u56de\u5c11\u306a\u304f\u306a\u3063\u3066\u3044\u308b<\/ul>\n<p>\u3069\u3046\u305b\u30b5\u30a4\u30ba\u304c\u5897\u3048\u308b\u306a\u3089\uff0cenum\u3092\u4f7f\u3063\u305f\u30bf\u30b0\u4ed8\u304d\u30dd\u30a4\u30f3\u30bf\u30fc\u306b\u3057\u3066\u3057\u307e\u3063\u305f\u307b\u3046\u304c\u826f\u3044\u30b1\u30fc\u30b9\u306f\u3042\u308b\u3067\u3057\u3087\u3046\uff0e<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">enum<\/span> <span class=\"n\">Geometry<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"nf\">Triangle<\/span><span class=\"p\">(<\/span><span class=\"nb\">Box<\/span><span class=\"o\">&lt;<\/span><span class=\"n\">Triangle<\/span><span class=\"o\">&gt;<\/span><span class=\"p\">),<\/span>\r\n    <span class=\"nf\">Rectangle<\/span><span class=\"p\">(<\/span><span class=\"nb\">Box<\/span><span class=\"o\">&lt;<\/span><span class=\"n\">Rectangle<\/span><span class=\"o\">&gt;<\/span><span class=\"p\">),<\/span>\r\n    <span class=\"o\">...<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"k\">let<\/span> <span class=\"n\">geom<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">Geometry<\/span><span class=\"p\">::<\/span><span class=\"nf\">Rectangle<\/span><span class=\"p\">(<\/span><span class=\"nn\">Box<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"nn\">Rectangle<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"mi\">10<\/span><span class=\"p\">,<\/span> <span class=\"mi\">10<\/span><span class=\"p\">)));<\/span>\r\n<\/code><\/pre>\n<pre class=\"post-pre\"><code>  <span class=\"nv\">%geom<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"p\">{<\/span> <span class=\"kt\">i64<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"p\">},<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n<\/code><\/pre>\n<p>\u30a4\u30f3\u30bf\u30fc\u30d5\u30a7\u30fc\u30b9\u3092\u7dba\u9e97\u306b\u62bd\u51fa\u53ef\u80fd\u306a\u5834\u5408\u306fBox&lt;\u30c8\u30ec\u30a4\u30c8&gt;\u3067\uff0c\u30c0\u30a6\u30f3\u30ad\u30e3\u30b9\u30c8\u3092\u591a\u7528\u3059\u308b\u30b1\u30fc\u30b9\uff08\u3053\u306e\u3088\u3046\u306a\u5834\u5408\u306f\u305d\u3082\u305d\u3082\u59a5\u5f53\u306a\u30c8\u30ec\u30a4\u30c8\u306f\u5b58\u5728\u3057\u306a\u3044\u3067\u3057\u3087\u3046\u304c\uff09\u306f\u30bf\u30b0\u4ed8\u304d\u30dd\u30a4\u30f3\u30bf\u30fc\u3092\u4f7f\u3046\u306e\u304c\u3088\u3044\u3067\u3057\u3087\u3046\uff0e<\/p>\n<h1>\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u30b3\u30d4\u30fc<\/h1>\n<p>Rust\u3067\u306f\uff0c\u4e00\u898b\u6700\u9069\u5316\u3067\u9664\u53bb\u3067\u304d\u305d\u3046\u306a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u30b3\u30d4\u30fc\u304c\u884c\u308f\u308c\u308b\u30b1\u30fc\u30b9\u304c\u3044\u304f\u3064\u304b\u5b58\u5728\u3059\u308b\u3088\u3046\u3067\u3059\uff0e<\/p>\n<h2>Box::new()\u3068\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u521d\u671f\u5316<\/h2>\n<p>\u95a2\u9023\u30b5\u30a4\u30c8<\/p>\n<ul class=\"post-ul\">cargo asm\u3067Rust\u306e\u30e1\u30e2\u30ea\u5468\u308a\u6700\u9069\u5316\u3092\u30c1\u30a7\u30c3\u30af | \u03baeen\u306eHappy Hac\u03baing Blog<\/ul>\n<p>\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092Box::new()\u3067\u30d2\u30fc\u30d7\u4e0a\u306b\u78ba\u4fdd\u3057\u305f\u5834\u5408\uff0c<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">struct<\/span> <span class=\"n\">X<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"n\">x<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i32<\/span><span class=\"p\">,<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"k\">fn<\/span> <span class=\"nf\">main<\/span><span class=\"p\">()<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"k\">let<\/span> <span class=\"n\">data<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">Box<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"n\">X<\/span> <span class=\"p\">{<\/span> <span class=\"n\">x<\/span><span class=\"p\">:<\/span> <span class=\"mi\">112<\/span> <span class=\"p\">});<\/span>\r\n    <span class=\"nd\">println!<\/span><span class=\"p\">(<\/span><span class=\"s\">\"{}\"<\/span><span class=\"p\">,<\/span> <span class=\"n\">data<\/span><span class=\"py\">.x<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<p>__rust_alloc\u5f8c\u306b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u521d\u671f\u5316\u304c\u884c\u308f\u308c\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code>  <span class=\"nv\">%0<\/span> <span class=\"p\">=<\/span> <span class=\"k\">tail<\/span> <span class=\"k\">call<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"vg\">@__rust_alloc<\/span><span class=\"p\">(<\/span><span class=\"kt\">i64<\/span> <span class=\"m\">4<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">4<\/span><span class=\"p\">)<\/span> <span class=\"vg\">#7<\/span>\r\n  <span class=\"p\">...<\/span>\r\n  <span class=\"nv\">%2<\/span> <span class=\"p\">=<\/span> <span class=\"k\">bitcast<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"nv\">%0<\/span> <span class=\"k\">to<\/span> <span class=\"kt\">i32<\/span><span class=\"p\">*<\/span>\r\n  <span class=\"k\">store<\/span> <span class=\"kt\">i32<\/span> <span class=\"m\">112<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i32<\/span><span class=\"p\">*<\/span> <span class=\"nv\">%2<\/span><span class=\"p\">,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">4<\/span>\r\n<\/code><\/pre>\n<p>\u30bf\u30d7\u30eb\u3082\u540c\u69d8\u306e\u7d50\u679c\u306b\u306a\u308a\u307e\u3059\uff0e<\/p>\n<p>\u3057\u304b\u3057\uff0c\u914d\u5217\u306f\u9055\u3044\u307e\u3059\uff0e\u914d\u5217\u306e\u5834\u5408\uff0c\u914d\u5217\u306e\u30b5\u30a4\u30ba\u304c\u304c\uff19\u30d0\u30a4\u30c8\u4ee5\u4e0a\u306b\u306a\u308b\u3068<\/p>\n<ul class=\"post-ul\">\n<li style=\"list-style-type: none;\">\n<ul class=\"post-ul\">\u30b9\u30bf\u30c3\u30af\u4e0a\u306b\u914d\u5217\u3092\u78ba\u4fdd\u3057\uff0c\u3053\u308c\u3092\u521d\u671f\u5316<\/ul>\n<\/li>\n<\/ul>\n<p>__rust_alloc\u3067\u30d2\u30fc\u30d7\u4e0a\u306b\u914d\u5217\u306e\u30e1\u30e2\u30ea\u3092\u78ba\u4fdd<br \/>\n\u30b9\u30bf\u30c3\u30af\u4e0a\u306e\u914d\u5217\u3092\u30d2\u30fc\u30d7\u306b\u30b3\u30d4\u30fc<\/p>\n<p>\u3068\u3044\u3046\u52d5\u4f5c\u306b\u306a\u308a\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">fn<\/span> <span class=\"nf\">main<\/span><span class=\"p\">()<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"k\">let<\/span> <span class=\"n\">data<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">Box<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">([<\/span><span class=\"mi\">112u8<\/span><span class=\"p\">;<\/span> <span class=\"mi\">9<\/span><span class=\"p\">]);<\/span>\r\n    <span class=\"nd\">println!<\/span><span class=\"p\">(<\/span><span class=\"s\">\"{}\"<\/span><span class=\"p\">,<\/span> <span class=\"n\">data<\/span><span class=\"p\">[<\/span><span class=\"mi\">0<\/span><span class=\"p\">]);<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<pre class=\"post-pre\"><code>  <span class=\"nv\">%_2<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"p\">[<\/span><span class=\"m\">9<\/span> <span class=\"p\">x<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">],<\/span> <span class=\"k\">align<\/span> <span class=\"m\">1<\/span>\r\n  <span class=\"nv\">%data<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"p\">[<\/span><span class=\"m\">9<\/span> <span class=\"p\">x<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">]*,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"p\">...<\/span>\r\n  <span class=\"nv\">%_2.0.sroa_idx6<\/span> <span class=\"p\">=<\/span> <span class=\"k\">getelementptr<\/span> <span class=\"k\">inbounds<\/span> <span class=\"p\">[<\/span><span class=\"m\">9<\/span> <span class=\"p\">x<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">],<\/span> <span class=\"p\">[<\/span><span class=\"m\">9<\/span> <span class=\"p\">x<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">]*<\/span> <span class=\"nv\">%_2<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">0<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">0<\/span>\r\n  <span class=\"p\">...<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@llvm.memset.p0i8.i64<\/span><span class=\"p\">(<\/span><span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">align<\/span> <span class=\"m\">1<\/span> <span class=\"nv\">%_2.0.sroa_idx6<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i8<\/span> <span class=\"m\">112<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">9<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i1<\/span> <span class=\"k\">false<\/span><span class=\"p\">)<\/span>\r\n  <span class=\"nv\">%1<\/span> <span class=\"p\">=<\/span> <span class=\"k\">tail<\/span> <span class=\"k\">call<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"vg\">@__rust_alloc<\/span><span class=\"p\">(<\/span><span class=\"kt\">i64<\/span> <span class=\"m\">9<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">1<\/span><span class=\"p\">)<\/span> <span class=\"vg\">#7<\/span><span class=\"p\">,<\/span> <span class=\"nv\">!noalias<\/span> <span class=\"nv\">!5<\/span>\r\n  <span class=\"p\">...<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@llvm.memcpy.p0i8.p0i8.i64<\/span><span class=\"p\">(<\/span><span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">align<\/span> <span class=\"m\">1<\/span> <span class=\"nv\">%1<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">align<\/span> <span class=\"m\">1<\/span> <span class=\"nv\">%_2.0.sroa_idx6<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">9<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i1<\/span> <span class=\"k\">false<\/span><span class=\"p\">)<\/span> <span class=\"vg\">#7<\/span>\r\n<\/code><\/pre>\n<p>\u3053\u306e\u52d5\u4f5c\u306b\u95a2\u9023\u3059\u308bIssue\u304c\u767b\u9332\u6e08\u307f\u3067\u3059\uff0e<\/p>\n<ul class=\"post-ul\">Boxed array initialisation with Box::new does not seem to optimise properly #41831<\/ul>\n<p>\u985e\u4f3c\u306e\u554f\u984c\u3068\u3057\u3066\uff0cBox&lt;[T; N]&gt;\u306eclone\u306e\u30b3\u30f3\u30d1\u30a4\u30eb\u7d50\u679c\u304c\u767b\u9332\u3055\u308c\u3066\u307e\u3059\uff0e<\/p>\n<p>Box::new()\u306b\u3064\u3044\u3066\u8aac\u660e\u3057\u307e\u3057\u305f\u304c\uff0c\u540c\u69d8\u306e\u554f\u984c\u306fRc::new()\u306a\u3069\u3067\u3082\u767a\u751f\u3057\u307e\u3059\uff0e<\/p>\n<h3>\u95a2\u6570\u547c\u3073\u51fa\u3057\u9806\u5e8f\u306e\u4e00\u8cab\u6027<\/h3>\n<p>Box::new(X::new())\u304c\u3069\u306e\u3088\u3046\u306a\u30b3\u30fc\u30c9\u306b\u30b3\u30f3\u30d1\u30a4\u30eb\u3055\u308c\u308b\u306e\u304b\u306f\u78ba\u8a8d\u304c\u5fc5\u8981\u3067\u3059\uff0e<\/p>\n<p>\u666e\u901a\u306b\u8003\u3048\u308b\u3068\uff0c\u4ed6\u306e\u95a2\u6570\u306e\u547c\u3073\u51fa\u3057\u9806\u3068\u306e\u4e00\u8cab\u6027\u304b\u3089<\/p>\n<ol>\n<li style=\"list-style-type: none;\">\n<ol>X::new()<\/ol>\n<\/li>\n<\/ol>\n<p>&nbsp;<\/p>\n<ol>Box::new()<\/ol>\n<p>\u306e\u9806\u756a\u3067\u547c\u3073\u51fa\u3057\u304c\u884c\u308f\u308c\u308b\u3079\u304d\u3067\u3059\uff0e<\/p>\n<p>Rust\u306b\u306fC++\u306e\u7d99\u627f\u306e\u3088\u3046\u306a\u6a5f\u80fd\u304c\u5b58\u5728\u305b\u305a\uff0c\u305d\u306e\u4ee3\u66ff\u3068\u3057\u3066<\/p>\n<pre class=\"post-pre\"><code><span class=\"c\">\/\/ C++\u3067\u306e`class T: public Base {};`\u306b\u76f8\u5f53<\/span>\r\n<span class=\"k\">struct<\/span> <span class=\"n\">Base<\/span><span class=\"o\">&lt;<\/span><span class=\"n\">T<\/span><span class=\"o\">&gt;<\/span> <span class=\"p\">{<\/span>\r\n  <span class=\"n\">data<\/span><span class=\"p\">:<\/span> <span class=\"n\">T<\/span><span class=\"p\">,<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<p>\u306e\u3088\u3046\u306a\u66f8\u304d\u65b9\u3092\u3059\u308b\u3053\u3068\u304c\u3088\u304f\u3042\u308a\u307e\u3059\uff0e\u305d\u306e\u305f\u3081\uff0c\u30a2\u30b0\u30ec\u30c3\u30b7\u30d6\u306a\u6700\u9069\u5316\u306e\u305f\u3081\u306b\uff0c\u4e0a\u8a18\u306e\u547c\u3073\u51fa\u3057\u9806\u5e8f\u306e\u4e00\u8cab\u6027\u3092\u72a0\u7272\u306b\u3059\u308b\u3053\u3068\u306b\u306a\u308a\u305d\u3046\u3067\u3059\uff0e<\/p>\n<p>\u5b9f\u969b\uff0cX::new()\u3092\u5b9f\u88c5\u3057\u3066\u78ba\u8a8d\u3057\u3066\u307f\u308b\u3068\uff0cBox::new(X { .. })\u306e\u5834\u5408\u3068\u540c\u69d8\u306b\uff0c__rust_alloc\u5f8c\u306b\u30d2\u30fc\u30d7\u4e0a\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u521d\u671f\u5316\u3059\u308b\u30b3\u30fc\u30c9\u304c\u751f\u6210\u3055\u308c\u308b\u3053\u3068\u304c\u5206\u304b\u308a\u307e\u3059\uff0e<\/p>\n<p>\u672a\u691c\u8a3c\u3067\u3059\u304c\uff0c\uff08\u30a4\u30f3\u30e9\u30a4\u30f3\u5c55\u958b\u3067\u304d\u306a\u3044\u304f\u3089\u3044\uff09\u3082\u3063\u3068\u8907\u96d1\u306anew()\u3092\u5b9f\u88c5\u3059\u308b\u3068\uff0cX::new()\u306e\u7d50\u679c\u3092\u30b9\u30bf\u30c3\u30af\u4e0a\u306b\u4e00\u5ea6\u4fdd\u5b58\u3059\u308b\u304b\u3082\u3057\u308c\u307e\u305b\u3093\uff08\u691c\u8a3c\u304c\u5fc5\u8981\u3060\u3068\u8003\u3048\u3066\u3044\u307e\u3059\uff09\uff0e<\/p>\n<h3>\u691c\u8a3c\u3057\u3066\u307f\u307e\u3057\u305f<\/h3>\n<p>X::new()\u306b#[inline(never)]\u3092\u3064\u3051\u3066\u691c\u8a3c\u3057\u3066\u307f\u307e\u3057\u305f\uff0e<\/p>\n<p>Rust Playground<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">struct<\/span> <span class=\"n\">X<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"n\">x1<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i64<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">x2<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i64<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">x3<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i64<\/span><span class=\"p\">,<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"k\">impl<\/span> <span class=\"n\">X<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"nd\">#[inline(never)]<\/span>\r\n    <span class=\"k\">fn<\/span> <span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"n\">x<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i64<\/span><span class=\"p\">)<\/span> <span class=\"k\">-&gt;<\/span> <span class=\"n\">X<\/span> <span class=\"p\">{<\/span>\r\n        <span class=\"n\">X<\/span> <span class=\"p\">{<\/span> <span class=\"n\">x1<\/span><span class=\"p\">:<\/span> <span class=\"n\">x<\/span><span class=\"p\">,<\/span> <span class=\"n\">x2<\/span><span class=\"p\">:<\/span> <span class=\"n\">x<\/span><span class=\"p\">,<\/span> <span class=\"n\">x3<\/span><span class=\"p\">:<\/span> <span class=\"n\">x<\/span><span class=\"p\">,<\/span> <span class=\"p\">}<\/span>\r\n    <span class=\"p\">}<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"k\">fn<\/span> <span class=\"nf\">main<\/span><span class=\"p\">()<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"k\">let<\/span> <span class=\"n\">data<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">Box<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"nn\">X<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"mi\">112<\/span><span class=\"p\">));<\/span>\r\n    <span class=\"nd\">println!<\/span><span class=\"p\">(<\/span><span class=\"s\">\"{}\"<\/span><span class=\"p\">,<\/span> <span class=\"n\">data<\/span><span class=\"py\">.x1<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<p>\u69cb\u9020\u4f53\u306e\u30b5\u30a4\u30ba\u304c\u5c0f\u3055\u3044\u3068#[inline(never)]\u3092\u3064\u3051\u3066\u3082X::new()\u304c\u306a\u304f\u306a\u308b\u306e\u3067\uff0c\u30b5\u30a4\u30ba\u3092\u5927\u304d\u304f\u3057\u3066\u3042\u308a\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code>  <span class=\"nv\">%_2<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"nv\">%X<\/span><span class=\"p\">,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"p\">...<\/span>\r\n  <span class=\"nv\">%1<\/span> <span class=\"p\">=<\/span> <span class=\"k\">bitcast<\/span> <span class=\"nv\">%X<\/span><span class=\"p\">*<\/span> <span class=\"nv\">%_2<\/span> <span class=\"k\">to<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span>\r\n  <span class=\"p\">...<\/span>\r\n<span class=\"c1\">; call playground::X::new<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"k\">fastcc<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@_ZN10playground1X3new17hd1b418a35221643aE<\/span><span class=\"p\">(<\/span><span class=\"nv\">%X<\/span><span class=\"p\">*<\/span> <span class=\"k\">noalias<\/span> <span class=\"k\">nocapture<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">dereferenceable<\/span><span class=\"p\">(<\/span><span class=\"m\">24<\/span><span class=\"p\">)<\/span> <span class=\"nv\">%_2<\/span><span class=\"p\">)<\/span>\r\n  <span class=\"nv\">%2<\/span> <span class=\"p\">=<\/span> <span class=\"k\">tail<\/span> <span class=\"k\">call<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"vg\">@__rust_alloc<\/span><span class=\"p\">(<\/span><span class=\"kt\">i64<\/span> <span class=\"m\">24<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">8<\/span><span class=\"p\">)<\/span> <span class=\"vg\">#8<\/span><span class=\"p\">,<\/span> <span class=\"nv\">!noalias<\/span> <span class=\"nv\">!5<\/span>\r\n  <span class=\"p\">...<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@llvm.memcpy.p0i8.p0i8.i64<\/span><span class=\"p\">(<\/span><span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span> <span class=\"nv\">%2<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span> <span class=\"nv\">%1<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">24<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i1<\/span> <span class=\"k\">false<\/span><span class=\"p\">)<\/span> <span class=\"vg\">#8<\/span>\r\n<\/code><\/pre>\n<p>\u30b9\u30bf\u30c3\u30af\u4e0a\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u5bfe\u3057\u3066X::new()\u3092\u547c\u3073\u51fa\u3057\uff0c\u305d\u308c\u3092Box::new()\u3067\u78ba\u4fdd\u3057\u3066\u30d2\u30fc\u30d7\u4e0a\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u30b3\u30d4\u30fc\u3057\u3066\u3044\u307e\u3059\uff0e<\/p>\n<p>\u3053\u306e\u3053\u3068\u304b\u3089\uff0c\u5927\u304d\u306a\u69cb\u9020\u4f53\u3092\u4f7f\u3046\u3088\u3046\u306a\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u3067\u306f\uff0c\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u751f\u6210\u30b3\u30b9\u30c8\u304cC\/C++\u306b\u6bd4\u3079\u3066\u5927\u304d\u304f\u306a\u308a\u307e\u3059\uff0e\u4f55\u3088\u308a\uff0c\u30b9\u30bf\u30c3\u30af\u306e\u6d88\u8cbb\u3092\u907f\u3051\u308b\u305f\u3081\u30d2\u30fc\u30d7\u304b\u3089\u78ba\u4fdd\u3057\u3088\u3046\u3068\u3057\u3066Box::new()\u306b\u7f6e\u304d\u63db\u3048\u305f\u3068\u3057\u3066\u3082\uff0c\u6539\u5584\u3055\u308c\u306a\u3044\u3068\u3044\u3046\u70b9\u304c\u4e00\u756a\u5927\u304d\u306a\u554f\u984c\u3067\u3059\uff0e<\/p>\n<h3>box\u69cb\u6587<\/h3>\n<p>box\u3092\u4f7f\u3048\u3070Box::new()\u306b\u95a2\u3057\u3066\u306f\u6539\u5584\u53ef\u80fd\u3067\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code><span class=\"nd\">#![feature(box_syntax)]<\/span>  <span class=\"c\">\/\/ added<\/span>\r\n\r\n<span class=\"k\">struct<\/span> <span class=\"n\">X<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"n\">x1<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i64<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">x2<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i64<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">x3<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i64<\/span><span class=\"p\">,<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"k\">impl<\/span> <span class=\"n\">X<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"nd\">#[inline(never)]<\/span>\r\n    <span class=\"k\">fn<\/span> <span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"n\">x<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i64<\/span><span class=\"p\">)<\/span> <span class=\"k\">-&gt;<\/span> <span class=\"n\">X<\/span> <span class=\"p\">{<\/span>\r\n        <span class=\"n\">X<\/span> <span class=\"p\">{<\/span> <span class=\"n\">x1<\/span><span class=\"p\">:<\/span> <span class=\"n\">x<\/span><span class=\"p\">,<\/span> <span class=\"n\">x2<\/span><span class=\"p\">:<\/span> <span class=\"n\">x<\/span><span class=\"p\">,<\/span> <span class=\"n\">x3<\/span><span class=\"p\">:<\/span> <span class=\"n\">x<\/span><span class=\"p\">,<\/span> <span class=\"p\">}<\/span>\r\n    <span class=\"p\">}<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"k\">fn<\/span> <span class=\"nf\">main<\/span><span class=\"p\">()<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"k\">let<\/span> <span class=\"n\">data<\/span> <span class=\"o\">=<\/span> <span class=\"k\">box<\/span> <span class=\"nn\">X<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"mi\">112<\/span><span class=\"p\">);<\/span>  <span class=\"c\">\/\/ modified<\/span>\r\n    <span class=\"nd\">println!<\/span><span class=\"p\">(<\/span><span class=\"s\">\"{}\"<\/span><span class=\"p\">,<\/span> <span class=\"n\">data<\/span><span class=\"py\">.x1<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<p>\u4e0a\u8a18\u306e\u3088\u3046\u306b\u66f8\u304d\u63db\u3048\uff0cNightly\u3067\u30d3\u30eb\u30c9\u3059\u308b\u3068<\/p>\n<pre class=\"post-pre\"><code>  <span class=\"nv\">%data<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"nv\">%X<\/span><span class=\"p\">*,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"p\">...<\/span>\r\n  <span class=\"nv\">%1<\/span> <span class=\"p\">=<\/span> <span class=\"k\">tail<\/span> <span class=\"k\">call<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"vg\">@__rust_alloc<\/span><span class=\"p\">(<\/span><span class=\"kt\">i64<\/span> <span class=\"m\">24<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">8<\/span><span class=\"p\">)<\/span> <span class=\"vg\">#8<\/span>\r\n  <span class=\"p\">...<\/span>\r\n  <span class=\"nv\">%3<\/span> <span class=\"p\">=<\/span> <span class=\"k\">bitcast<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"nv\">%1<\/span> <span class=\"k\">to<\/span> <span class=\"nv\">%X<\/span><span class=\"p\">*<\/span>\r\n<span class=\"c1\">; call playground::X::new<\/span>\r\n  <span class=\"k\">tail<\/span> <span class=\"k\">call<\/span> <span class=\"k\">fastcc<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@_ZN10playground1X3new17h0ce0962a98843dbaE<\/span><span class=\"p\">(<\/span><span class=\"nv\">%X<\/span><span class=\"p\">*<\/span> <span class=\"k\">noalias<\/span> <span class=\"k\">nocapture<\/span> <span class=\"k\">dereferenceable<\/span><span class=\"p\">(<\/span><span class=\"m\">24<\/span><span class=\"p\">)<\/span> <span class=\"nv\">%3<\/span><span class=\"p\">)<\/span>\r\n  <span class=\"nv\">%4<\/span> <span class=\"p\">=<\/span> <span class=\"k\">bitcast<\/span> <span class=\"nv\">%X<\/span><span class=\"p\">**<\/span> <span class=\"nv\">%data<\/span> <span class=\"k\">to<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">**<\/span>\r\n  <span class=\"k\">store<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"nv\">%1<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">**<\/span> <span class=\"nv\">%4<\/span><span class=\"p\">,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n\r\n<\/code><\/pre>\n<p>\u30b9\u30bf\u30c3\u30af\u4e0a\u306b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u78ba\u4fdd\u305b\u305a\uff0c\u30d2\u30fc\u30d7\u4e0a\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u5bfe\u3057\u3066X::new()\u304c\u547c\u3073\u51fa\u3055\u308c\u307e\u3059\uff0e\u307e\u305f\uff0c\u95a2\u6570\u547c\u3073\u51fa\u3057\u9806\u5e8f\u306e\u4e00\u8cab\u6027\u3082\u4fdd\u305f\u308c\u307e\u3059\uff0e<\/p>\n<h3>\u914d\u7f6e\u69cb\u6587<\/h3>\n<p>Box::new()\u306e\u554f\u984c\u306fbox\u3092\u4f7f\u3046\u3053\u3068\u3067\u89e3\u6c7a\u3067\u304d\u307e\u3059\u304c\uff0cRc::new()\u306a\u3069\u4ed6\u306b\u3082\u30d2\u30fc\u30d7\u304b\u3089\u30e1\u30e2\u30ea\u3092\u5272\u308a\u5f53\u3066\u308b\u95a2\u6570\u306f\u5b58\u5728\u3057\u307e\u3059\uff0e\u3053\u308c\u3089\u306b\u3064\u3044\u3066\u306f\u5f53\u7136box\u3067\u306f\u554f\u984c\u3092\u89e3\u6c7a\u3067\u304d\u307e\u305b\u3093\uff0e<\/p>\n<p>\u4e00\u9023\u306e\u30b3\u30d4\u30fc\u30b3\u30b9\u30c8\u306e\u554f\u984c\u3092\u89e3\u6c7a\u3059\u308b\u305f\u3081\u914d\u7f6e\u69cb\u6587\u304c\u63d0\u6848\u3055\u308c\u3066\u3044\u307e\u3057\u305f\uff0e<\/p>\n<ul class=\"post-ul\">\n<li style=\"list-style-type: none;\">\n<ul class=\"post-ul\">Tracking issue for placement new \u00b7 Issue #27779 \u00b7 rust-lang\/rust<\/ul>\n<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<ul class=\"post-ul\">Rust\u306e\u914d\u7f6e\u69cb\u6587\u3068box\u69cb\u6587 &#8211; \u7c21\u6f54\u306aQ<\/ul>\n<p>\u3057\u304b\u3057\uff0c\u6700\u7d42\u7684\u306b\u306funstable\u304b\u3089\u3082\u524a\u9664\u3055\u308c\u305f\u3088\u3046\u3067\u3059\uff0e<\/p>\n<ul class=\"post-ul\">Remove all unstable placement features by aidanhs \u00b7 Pull Request #48333 \u00b7 rust-lang\/rust<\/ul>\n<p>\u3061\u306a\u307f\u306b\uff0cRc::new()\u306f\uff0c\u30d2\u30fc\u30d7\u304b\u3089\u30e1\u30e2\u30ea\u3092\u5272\u308a\u5f53\u3066\u308b\u305f\u3081\u306bbox\u69cb\u6587\u3092\u4f7f\u7528\u3057\u3066\u3044\u307e\u3059\u304c\uff0c\u30a4\u30f3\u30e9\u30a4\u30f3\u5c55\u958b\u3055\u308c\u306a\u3044\u305f\u3081\u30b9\u30bf\u30c3\u30af\u4e0a\u306b\u4e00\u6642\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c\u4f5c\u6210\u3055\u308c\u307e\u3059\uff0e\u591a\u5206\uff0c\u30a4\u30f3\u30e9\u30a4\u30f3\u5c55\u958b\u3059\u308c\u3070\u6539\u5584\u3055\u308c\u308b\u3068\u601d\u308f\u308c\u307e\u3059\uff0e<\/p>\n<h2>\u623b\u308a\u5024\u306e\u4ee3\u5165<\/h2>\n<p>\u95a2\u6570\u306e\u623b\u308a\u5024\u3092\u4ee3\u5165\u3059\u308b\u5834\u5408\uff0c\u4f59\u8a08\u306a\u30b9\u30bf\u30c3\u30af\u304b\u3089\u306e\u30b3\u30d4\u30fc\u304c\u767a\u751f\u3059\u308b\u5834\u5408\u304c\u3042\u308a\u307e\u3059\uff0e<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">struct<\/span> <span class=\"n\">X<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"n\">x1<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i64<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">x2<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i64<\/span><span class=\"p\">,<\/span>\r\n    <span class=\"n\">x3<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i64<\/span><span class=\"p\">,<\/span>  <span class=\"c\">\/\/ \u3053\u308c\u3092\u6d88\u3059\u3068\u30ec\u30b8\u30b9\u30bf\u3060\u3051\u3067\u30b3\u30d4\u30fc\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u308a\uff0c\u30b9\u30bf\u30c3\u30af\u304b\u3089\u306e\u30b3\u30d4\u30fc\u56de\u6570\u304c\u6e1b\u308b<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"k\">impl<\/span> <span class=\"n\">X<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"nd\">#[inline(never)]<\/span>\r\n    <span class=\"k\">fn<\/span> <span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"n\">x<\/span><span class=\"p\">:<\/span> <span class=\"nb\">i64<\/span><span class=\"p\">)<\/span> <span class=\"k\">-&gt;<\/span> <span class=\"n\">X<\/span> <span class=\"p\">{<\/span>\r\n        <span class=\"n\">X<\/span> <span class=\"p\">{<\/span> <span class=\"n\">x1<\/span><span class=\"p\">:<\/span> <span class=\"n\">x<\/span><span class=\"p\">,<\/span> <span class=\"n\">x2<\/span><span class=\"p\">:<\/span> <span class=\"n\">x<\/span><span class=\"p\">,<\/span> <span class=\"n\">x3<\/span><span class=\"p\">:<\/span> <span class=\"n\">x<\/span><span class=\"p\">,<\/span> <span class=\"p\">}<\/span>\r\n    <span class=\"p\">}<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"nd\">#[inline(never)]<\/span>\r\n<span class=\"k\">fn<\/span> <span class=\"nf\">p<\/span><span class=\"p\">(<\/span><span class=\"n\">x<\/span><span class=\"p\">:<\/span> <span class=\"o\">&amp;<\/span><span class=\"n\">X<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"nd\">println!<\/span><span class=\"p\">(<\/span><span class=\"s\">\"{}\"<\/span><span class=\"p\">,<\/span> <span class=\"n\">x<\/span><span class=\"py\">.x1<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"k\">fn<\/span> <span class=\"nf\">main<\/span><span class=\"p\">()<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"k\">let<\/span> <span class=\"k\">mut<\/span> <span class=\"n\">data<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">X<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"mi\">112<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"nf\">p<\/span><span class=\"p\">(<\/span><span class=\"o\">&amp;<\/span><span class=\"n\">data<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"n\">data<\/span> <span class=\"o\">=<\/span> <span class=\"nn\">X<\/span><span class=\"p\">::<\/span><span class=\"nf\">new<\/span><span class=\"p\">(<\/span><span class=\"mi\">123<\/span><span class=\"p\">);<\/span>\r\n    <span class=\"nf\">p<\/span><span class=\"p\">(<\/span><span class=\"o\">&amp;<\/span><span class=\"n\">data<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<pre class=\"post-pre\"><code>  <span class=\"nv\">%_5<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"nv\">%X<\/span><span class=\"p\">,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"nv\">%data<\/span> <span class=\"p\">=<\/span> <span class=\"k\">alloca<\/span> <span class=\"nv\">%X<\/span><span class=\"p\">,<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span>\r\n  <span class=\"p\">...<\/span>\r\n<span class=\"c1\">; call playground::X::new<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"k\">fastcc<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@_ZN10playground1X3new17h4bea4d29da321a4dE<\/span><span class=\"p\">(<\/span><span class=\"nv\">%X<\/span><span class=\"p\">*<\/span> <span class=\"k\">noalias<\/span> <span class=\"k\">nocapture<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">dereferenceable<\/span><span class=\"p\">(<\/span><span class=\"m\">24<\/span><span class=\"p\">)<\/span> <span class=\"nv\">%data<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">112<\/span><span class=\"p\">)<\/span>\r\n<span class=\"c1\">; call playground::p<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"k\">fastcc<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@_ZN10playground1p17hdbe1cc8eb37ada0dE<\/span><span class=\"p\">(<\/span><span class=\"nv\">%X<\/span><span class=\"p\">*<\/span> <span class=\"k\">noalias<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">readonly<\/span> <span class=\"k\">dereferenceable<\/span><span class=\"p\">(<\/span><span class=\"m\">24<\/span><span class=\"p\">)<\/span> <span class=\"nv\">%data<\/span><span class=\"p\">)<\/span>\r\n  <span class=\"nv\">%1<\/span> <span class=\"p\">=<\/span> <span class=\"k\">bitcast<\/span> <span class=\"nv\">%X<\/span><span class=\"p\">*<\/span> <span class=\"nv\">%_5<\/span> <span class=\"k\">to<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@llvm.lifetime.start.p0i8<\/span><span class=\"p\">(<\/span><span class=\"kt\">i64<\/span> <span class=\"m\">24<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"k\">nonnull<\/span> <span class=\"nv\">%1<\/span><span class=\"p\">)<\/span>\r\n<span class=\"c1\">; call playground::X::new<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"k\">fastcc<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@_ZN10playground1X3new17h4bea4d29da321a4dE<\/span><span class=\"p\">(<\/span><span class=\"nv\">%X<\/span><span class=\"p\">*<\/span> <span class=\"k\">noalias<\/span> <span class=\"k\">nocapture<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">dereferenceable<\/span><span class=\"p\">(<\/span><span class=\"m\">24<\/span><span class=\"p\">)<\/span> <span class=\"nv\">%_5<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">123<\/span><span class=\"p\">)<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@llvm.memcpy.p0i8.p0i8.i64<\/span><span class=\"p\">(<\/span><span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span> <span class=\"nv\">%0<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"k\">nonnull<\/span> <span class=\"k\">align<\/span> <span class=\"m\">8<\/span> <span class=\"nv\">%1<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i64<\/span> <span class=\"m\">24<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i1<\/span> <span class=\"k\">false<\/span><span class=\"p\">)<\/span>\r\n  <span class=\"k\">call<\/span> <span class=\"kt\">void<\/span> <span class=\"vg\">@llvm.lifetime.end.p0i8<\/span><span class=\"p\">(<\/span><span class=\"kt\">i64<\/span> <span class=\"m\">24<\/span><span class=\"p\">,<\/span> <span class=\"kt\">i8<\/span><span class=\"p\">*<\/span> <span class=\"k\">nonnull<\/span> <span class=\"nv\">%1<\/span><span class=\"p\">)<\/span>\r\n<\/code><\/pre>\n<p>C++\u306b\u306foperator=\u304c\u3042\u308b\u306e\u3067\u7406\u89e3\u3067\u304d\u308b\u306e\u3067\u3059\u304c\uff0cRust\u306b\u306f\u8a72\u5f53\u3059\u308b\u3082\u306e\u304c\u306a\u3044\u306e\u3067\u6700\u9069\u5316\u3067\u30b9\u30bf\u30c3\u30af\u304b\u3089\u306e\u30b3\u30d4\u30fc\u3092\u306a\u304f\u3059\u3053\u3068\u304c\u53ef\u80fd\u306a\u3088\u3046\u306b\u601d\u308f\u308c\u307e\u3059\uff0e\u305d\u308c\u3068\u3082\uff0cCopy\u3084Clone\u3092\u8003\u616e\u3059\u308b\u3068\u30b9\u30bf\u30c3\u30af\u304b\u3089\u306e\u30b3\u30d4\u30fc\u304c\u5fc5\u8981\u306a\u306e\u3067\u3057\u3087\u3046\u304b\uff1f<\/p>\n<h1>\u501f\u7528\u3068\u6700\u9069\u5316<\/h1>\n<p>\u6240\u6709\u6a29\u306e\u7dad\u6301\u306e\u305f\u3081\uff0c\u95a2\u6570\u547c\u3073\u51fa\u3057\u6642\u306b\u53c2\u7167\u3092\u6e21\u3059\u3053\u3068\u306f\u591a\u3005\u3042\u308b\u3068\u601d\u3044\u307e\u3059\uff0e\u3057\u304b\u3057\uff0c\u3053\u308c\u304c\u539f\u56e0\u3067C\/C++\u306b\u6bd4\u3079\u3066\u6700\u9069\u5316\u304c\u9032\u307e\u306a\u3044\u3053\u3068\u304c\u3042\u308b\u3088\u3046\u3067\u3059\uff0e<\/p>\n<p>\u4f8b\u3048\u3070\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u30b3\u30fc\u30c9\u306f<\/p>\n<pre class=\"post-pre\"><code><span class=\"nd\">#[inline(never)]<\/span>\r\n<span class=\"k\">fn<\/span> <span class=\"nf\">p<\/span><span class=\"p\">(<\/span><span class=\"n\">x<\/span><span class=\"p\">:<\/span> <span class=\"o\">&amp;<\/span><span class=\"nb\">i32<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"nd\">println!<\/span><span class=\"p\">(<\/span><span class=\"s\">\"{}\"<\/span><span class=\"p\">,<\/span> <span class=\"n\">x<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"k\">fn<\/span> <span class=\"nf\">main<\/span><span class=\"p\">()<\/span> <span class=\"p\">{<\/span>\r\n    <span class=\"k\">let<\/span> <span class=\"n\">d<\/span> <span class=\"o\">=<\/span> <span class=\"mi\">1<\/span><span class=\"p\">;<\/span>\r\n    <span class=\"nf\">p<\/span><span class=\"p\">(<\/span><span class=\"o\">&amp;<\/span><span class=\"n\">d<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<pre class=\"post-pre\"><code>playground::main:\r\n    pushq   %rax\r\n    movl    $1, 4(%rsp)\r\n    leaq    4(%rsp), %rdi\r\n    callq   playground::p\r\n    popq    %rax\r\n    retq\r\n<\/code><\/pre>\n<p>\u306e\u3088\u3046\u306b\u4e00\u5ea6\u30b9\u30bf\u30c3\u30af\u306b\u5024\u3092\u66f8\u304d\u8fbc\u307f\uff0c\u66f8\u304d\u8fbc\u307f\u5148\u30a2\u30c9\u30ec\u30b9\u3092\u5f15\u6570\u3068\u3057\u3066\u95a2\u6570\u3092\u547c\u3073\u51fa\u3059\u3088\u3046\u306b\u30b3\u30f3\u30d1\u30a4\u30eb\u3055\u308c\u307e\u3059\uff0e\u7d20\u76f4\u306a\u7d50\u679c\u3067\u3059\uff0e<\/p>\n<p>\u3068\u3053\u308d\u304c\uff0cC\/C++\u3067\u540c\u3058\u3088\u3046\u306a\u30b3\u30fc\u30c9\u3092\u66f8\u304f\u3068\uff08\u4ee5\u4e0b\u306fC\u306e\u4f8b\u3067\u3059\u304c\uff0cC++\u3067\u3082\u57fa\u672c\u7684\u306b\u306f\u540c\u3058\u3067\u3059\uff09\uff0c<\/p>\n<pre class=\"post-pre\"><code><span class=\"cp\">#include &lt;stdio.h&gt;\r\n<\/span>\r\n<span class=\"k\">static<\/span> <span class=\"kt\">void<\/span> <span class=\"nf\">__attribute__<\/span> <span class=\"p\">((<\/span><span class=\"n\">noinline<\/span><span class=\"p\">))<\/span> <span class=\"n\">p<\/span><span class=\"p\">(<\/span><span class=\"kt\">int<\/span><span class=\"o\">*<\/span> <span class=\"n\">x<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\r\n  <span class=\"n\">printf<\/span><span class=\"p\">(<\/span><span class=\"s\">\"%d<\/span><span class=\"se\">\\n<\/span><span class=\"s\">\"<\/span><span class=\"p\">,<\/span> <span class=\"o\">*<\/span><span class=\"n\">x<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"kt\">int<\/span> <span class=\"nf\">main<\/span><span class=\"p\">(<\/span><span class=\"kt\">int<\/span> <span class=\"n\">argc<\/span><span class=\"p\">,<\/span> <span class=\"kt\">char<\/span><span class=\"o\">**<\/span> <span class=\"n\">argv<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\r\n  <span class=\"kt\">int<\/span> <span class=\"n\">a<\/span> <span class=\"o\">=<\/span> <span class=\"mi\">1<\/span><span class=\"p\">;<\/span>\r\n  <span class=\"n\">p<\/span><span class=\"p\">(<\/span><span class=\"o\">&amp;<\/span><span class=\"n\">a<\/span><span class=\"p\">);<\/span>\r\n  <span class=\"k\">return<\/span> <span class=\"mi\">0<\/span><span class=\"p\">;<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<pre class=\"post-pre\"><code>_main:                                  ## @main\r\n    .cfi_startproc\r\n## %bb.0:\r\n    pushq   %rbp\r\n    .cfi_def_cfa_offset 16\r\n    .cfi_offset %rbp, -16\r\n    movq    %rsp, %rbp\r\n    .cfi_def_cfa_register %rbp\r\n    movl    $1, %edi\r\n    callq   _p\r\n    xorl    %eax, %eax\r\n    popq    %rbp\r\n    retq\r\n    .cfi_endproc\r\n<\/code><\/pre>\n<p>\u5373\u5024\u3067\u95a2\u6570\u3092\u547c\u3073\u51fa\u3059\u3088\u3046\u306b\u66f8\u304d\u63db\u3048\u3089\u308c\u307e\u3059\uff08\u547c\u3073\u51fa\u3055\u308c\u308b\u95a2\u6570\u306e\u30b3\u30fc\u30c9\u3082\u542b\u3081\u3066\uff09\uff0e\u304b\u306a\u308a\u30a2\u30b0\u30ec\u30c3\u30b7\u30d6\u3067\u3059\uff0e<\/p>\n<p>\u3057\u304b\u3057\uff0c\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u5909\u66f4\u3059\u308b\u3068<\/p>\n<pre class=\"post-pre\"><code><span class=\"cp\">#include &lt;stdio.h&gt;\r\n<\/span>\r\n<span class=\"k\">static<\/span> <span class=\"kt\">void<\/span> <span class=\"nf\">__attribute__<\/span> <span class=\"p\">((<\/span><span class=\"n\">noinline<\/span><span class=\"p\">))<\/span> <span class=\"n\">p<\/span><span class=\"p\">(<\/span><span class=\"kt\">int<\/span><span class=\"o\">*<\/span> <span class=\"n\">x<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\r\n  <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"n\">x<\/span> <span class=\"o\">!=<\/span> <span class=\"nb\">NULL<\/span><span class=\"p\">)<\/span>  <span class=\"c1\">\/\/ \u8ffd\u52a0<\/span>\r\n    <span class=\"n\">printf<\/span><span class=\"p\">(<\/span><span class=\"s\">\"%d<\/span><span class=\"se\">\\n<\/span><span class=\"s\">\"<\/span><span class=\"p\">,<\/span> <span class=\"o\">*<\/span><span class=\"n\">x<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"kt\">int<\/span> <span class=\"nf\">main<\/span><span class=\"p\">(<\/span><span class=\"kt\">int<\/span> <span class=\"n\">argc<\/span><span class=\"p\">,<\/span> <span class=\"kt\">char<\/span><span class=\"o\">**<\/span> <span class=\"n\">argv<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\r\n  <span class=\"kt\">int<\/span> <span class=\"n\">a<\/span> <span class=\"o\">=<\/span> <span class=\"mi\">1<\/span><span class=\"p\">;<\/span>\r\n  <span class=\"n\">p<\/span><span class=\"p\">(<\/span><span class=\"o\">&amp;<\/span><span class=\"n\">a<\/span><span class=\"p\">);<\/span>\r\n  <span class=\"k\">return<\/span> <span class=\"mi\">0<\/span><span class=\"p\">;<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<pre class=\"post-pre\"><code>_main:                                  ## @main\r\n    .cfi_startproc\r\n## %bb.0:\r\n    pushq   %rbp\r\n    .cfi_def_cfa_offset 16\r\n    .cfi_offset %rbp, -16\r\n    movq    %rsp, %rbp\r\n    .cfi_def_cfa_register %rbp\r\n    subq    $16, %rsp\r\n    movl    $1, -4(%rbp)\r\n    leaq    -4(%rbp), %rdi\r\n    callq   _p\r\n    xorl    %eax, %eax\r\n    addq    $16, %rsp\r\n    popq    %rbp\r\n    retq\r\n    .cfi_endproc\r\n<\/code><\/pre>\n<p>Rust\u306e\u4f8b\u3068\u540c\u3058\u3088\u3046\u306b\u30b9\u30bf\u30c3\u30af\u4e0a\u306e\u30a2\u30c9\u30ec\u30b9\u3092\u6e21\u3059\u3088\u3046\u306b\u306a\u308a\u307e\u3059\uff0e\u63a8\u6e2c\u306b\u3059\u304e\u307e\u305b\u3093\u304c\uff0cRust\u306e\u4f8b\u306f\uff0c\u5185\u90e8\u7684\u306b\u306fNULL\u30c1\u30a7\u30c3\u30af\u3092\u4f34\u3046\u3088\u3046\u306a\u30d7\u30ed\u30b0\u30e9\u30e0\u306b\u5c55\u958b\u3055\u308c\u3066\u3044\u308b\u3068\u8003\u3048\u3089\u308c\u307e\u3059\uff0eRust\u3067\u306f\u501f\u7528\u304cNULL\u306b\u306a\u308b\u3053\u3068\u306f\u3042\u308a\u3048\u306a\u3044\u306e\u3067\u3059\u304c\uff0e<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u672c\u8a18\u4e8b\u3067\u306f\uff0crustc\u304c\u751f\u6210\u3059\u308b\u30b3\u30fc\u30c9\u306b\u3064\u3044\u3066\u306e\u8abf\u67fb\u3092\u884c\u3063\u3066\u3044\u307e\u3059\uff0e \u8a18\u4e8b\u306f\u968f\u6642\u66f4\u65b0\u3055\u308c\u307e\u3059\uff0e \u6700\u521d\u306e\u8a18\u4e8b\u3092\u66f8 [&hellip;]<\/p>\n","protected":false},"author":10,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-45638","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v21.5 (Yoast SEO v21.5) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>- Blog - Silicon Cloud<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.silicloud.com\/zh\/blog\/45638-2\/\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:description\" content=\"\u672c\u8a18\u4e8b\u3067\u306f\uff0crustc\u304c\u751f\u6210\u3059\u308b\u30b3\u30fc\u30c9\u306b\u3064\u3044\u3066\u306e\u8abf\u67fb\u3092\u884c\u3063\u3066\u3044\u307e\u3059\uff0e \u8a18\u4e8b\u306f\u968f\u6642\u66f4\u65b0\u3055\u308c\u307e\u3059\uff0e \u6700\u521d\u306e\u8a18\u4e8b\u3092\u66f8 [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.silicloud.com\/zh\/blog\/45638-2\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog - Silicon Cloud\" \/>\n<meta property=\"article:published_time\" content=\"2023-02-28T11:44:35+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2024-04-30T11:51:22+00:00\" \/>\n<meta name=\"author\" content=\"\u5b87, \u534e\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u4f5c\u8005\" \/>\n\t<meta name=\"twitter:data1\" content=\"\u5b87, \u534e\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4\" \/>\n\t<meta name=\"twitter:data2\" content=\"7 \u5206\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.silicloud.com\/zh\/blog\/45638-2\/\",\"url\":\"https:\/\/www.silicloud.com\/zh\/blog\/45638-2\/\",\"name\":\"- Blog - Silicon Cloud\",\"isPartOf\":{\"@id\":\"https:\/\/www.silicloud.com\/zh\/blog\/#website\"},\"datePublished\":\"2023-02-28T11:44:35+00:00\",\"dateModified\":\"2024-04-30T11:51:22+00:00\",\"author\":{\"@id\":\"https:\/\/www.silicloud.com\/zh\/blog\/#\/schema\/person\/513018e4e121d3add1b7c5de8be21458\"},\"inLanguage\":\"zh-Hans\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.silicloud.com\/zh\/blog\/45638-2\/\"]}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.silicloud.com\/zh\/blog\/#website\",\"url\":\"https:\/\/www.silicloud.com\/zh\/blog\/\",\"name\":\"Blog - Silicon 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