187185 2018-06-29 10:53:23 -0700 [lldb-webkit] Non-empty strings may be pretty-printed as empty 2018-06-29 16:19:49 -0700 1 1 1 Unclassified WebKit Tools / Tests WebKit Local Build Mac Unspecified RESOLVED FIXED InRadar P2 Normal --- 1 dbates dbates darin lforschler msaboff saam simon.fraser webkit-bug-importer ysuzuki oldest_to_newest 1437829 0 dbates 2018-06-29 10:53:23 -0700 Today, I set a breakpoint at <https://trac.webkit.org/browser/trunk/Source/WebCore/platform/network/cocoa/ResourceRequestCocoa.mm?rev=233316#L91>. Using a debug built of WebKit, I started MiniBrowser and opened a new WK2 window. When the breakpoint was hit I ran `p m_url.string()`. LLDB emitted the following: (lldb) p m_url.string() (const WTF::String) $9 = { length = 0, contents = '' } { m_impl = { m_ptr = 0x000000011ce6fb18 { length = 0, is8bit = 0, contents = '' } } } But m_url.string() is not an empty string: (lldb) p m_url.string().isEmpty() (bool) $10 = false I am using Xcode 10.0 (10L177m) on macOS Mojave (18A323). 1437830 1 dbates 2018-06-29 10:53:59 -0700 $ Tools/Scripts/dump-class-layout -c Debug JavaScriptCore StringImpl Found 1 types matching "StringImpl" in "/Volumes/.../WebKitBuild/Debug/JavaScriptCore.framework/JavaScriptCore" for x86_64 +0 { 24} StringImpl +0 { 24} WTF::StringImplShape +0 < 4> unsigned int m_refCount; +4 < 4> unsigned int m_length; +8 < 8> WTF::StringImplShape::(anonymous union) None; +16 < 4> unsigned int m_hashAndFlags; +20 < 4> <PADDING> +20 < 4> <PADDING> Total byte size: 24 Total pad bytes: 8 Padding percentage: 33.33 % 1437834 2 dbates 2018-06-29 10:56:24 -0700 dump-class-layout does not have an issue resolving that WTF::StringImpl is effectively a WTF::StringImplShape. The LLDB repl seems to have an issue with this. 1437836 3 343923 dbates 2018-06-29 11:05:50 -0700 Created attachment 343923 Patch 1437962 4 dbates 2018-06-29 16:18:03 -0700 Committed r233375: <https://trac.webkit.org/changeset/233375> 1437964 5 webkit-bug-importer 2018-06-29 16:19:49 -0700 <rdar://problem/41657759> 343923 2018-06-29 11:05:50 -0700 2018-06-29 16:13:09 -0700 Patch bug-187185-20180629110549.patch text/plain 2725 dbates U3VidmVyc2lvbiBSZXZpc2lvbjogMjMzMzE2CmRpZmYgLS1naXQgYS9Ub29scy9DaGFuZ2VMb2cg Yi9Ub29scy9DaGFuZ2VMb2cKaW5kZXggYjQ3NmM2NTVjNjI5ODY5NTVhMzU3ODQ5MmEzZDhkYzc4 ZjFmZjI4NC4uOWJlNmIxNmYyNTkxMzhkZjFiMzU4MDEyNWM3YjhmNmRkZDEyOTE3NSAxMDA2NDQK LS0tIGEvVG9vbHMvQ2hhbmdlTG9nCisrKyBiL1Rvb2xzL0NoYW5nZUxvZwpAQCAtMSwzICsxLDIz IEBACisyMDE4LTA2LTI5ICBEYW5pZWwgQmF0ZXMgIDxkYWJhdGVzQGFwcGxlLmNvbT4KKworICAg ICAgICBbbGxkYi13ZWJraXRdIE5vbi1lbXB0eSBzdHJpbmdzIG1heSBiZSBwcmV0dHktcHJpbnRl ZCBhcyBlbXB0eQorICAgICAgICBodHRwczovL2J1Z3Mud2Via2l0Lm9yZy9zaG93X2J1Zy5jZ2k/ aWQ9MTg3MTg1CisKKyAgICAgICAgUmV2aWV3ZWQgYnkgTk9CT0RZIChPT1BTISkuCisKKyAgICAg ICAgRm9yIHNvbWUgcmVhc29uIGxsZGIoMSkgc29tZXRpbWVzIGhhcyBhbiBpc3N1ZSBhY2Nlc3Np bmcgbWVtYmVycyBvZiBXVEY6OlN0cmluZ0ltcGxTaGFwZQorICAgICAgICB2aWEgYSBXVEY6OlN0 cmluZ0ltcGwgcG9pbnRlciAod2h5PykuIEV4cGxpY2l0bHkgY2FzdGluZyBhIFdURjo6U3RyaW5n SW1wbCogdG8gYQorICAgICAgICBXVEY6OlN0cmluZ0ltcGxTaGFwZSogYmVmb3JlIGFjY2Vzc2lu ZyBzdWNoIG1lbWJlcnMgbWFrZXMgTExEQiBoYXBweS4KKworICAgICAgICBJIHRyaWVkIHdyaXRp bmcgYSB0ZXN0IGZvciB0aGlzIGJvdGggZm9yIHRoZSBMTFZNIHByb2plY3QgYW5kIExMREIgdG8g bm8gYXZhaWwuIEkgaGF2ZSBvbmx5CisgICAgICAgIGJlZW4gYWJsZSB0byByZXByb2R1Y2UgdGhp cyBidWcgc3BvcmFkaWNhbGx5IGR1cmluZyBteSBXZWJDb3JlL1dlYktpdCBkZWJ1Z2dpbmcgc2Vz c2lvbnMgc28KKyAgICAgICAgZmFyLgorCisgICAgICAgICogbGxkYi9sbGRiX3dlYmtpdC5weToK KyAgICAgICAgKFdURlN0cmluZ0ltcGxQcm92aWRlci5fX2luaXRfXyk6IEV4cGxpY2l0bHkgY2Fz dCB0aGUgV1RGOjpTdHJpbmdJbXBsKiB0byBXVEY6OlN0cmluZ0ltcGxTaGFwZSouCisgICAgICAg IChXVEZTdHJpbmdJbXBsUHJvdmlkZXIuZ2V0X2RhdGE4KTogVXBkYXRlIGNvZGUgbm93IHRoYXQg d2UgYXJlIGRpcmVjdGx5IGFjY2Vzc2luZyBXVEY6OlN0cmluZ0ltcGxTaGFwZSouCisgICAgICAg IChXVEZTdHJpbmdJbXBsUHJvdmlkZXIuZ2V0X2RhdGExNik6IERpdHRvLgorCiAyMDE4LTA2LTI4 ICBEYW5pZWwgQmF0ZXMgIDxkYWJhdGVzQGFwcGxlLmNvbT4KIAogICAgICAgICBGaXggdGhlIGlP UyBidWlsZCBmb2xsb3dpbmcgcjIzMzI5OQpkaWZmIC0tZ2l0IGEvVG9vbHMvbGxkYi9sbGRiX3dl YmtpdC5weSBiL1Rvb2xzL2xsZGIvbGxkYl93ZWJraXQucHkKaW5kZXggMzRjNjRjMzQ1MzI5ZTA2 YTc1ODMwOTE2OTA3ZDMxYzdjNzRmNTM3Ni4uNTJmYjdhNDQzMmM0N2UwNTkzZDQ4ZjM2M2M3NTU5 Mjg5MGVkMzg4OSAxMDA2NDQKLS0tIGEvVG9vbHMvbGxkYi9sbGRiX3dlYmtpdC5weQorKysgYi9U b29scy9sbGRiL2xsZGJfd2Via2l0LnB5CkBAIC0yMzEsMTYgKzIzMSwxOSBAQCBkZWYgbHN0cmlu Z190b19zdHJpbmcodmFsb2JqLCBlcnJvciwgbGVuZ3RoPU5vbmUpOgogCiBjbGFzcyBXVEZTdHJp bmdJbXBsUHJvdmlkZXI6CiAgICAgZGVmIF9faW5pdF9fKHNlbGYsIHZhbG9iaiwgZGljdCk6Ci0g ICAgICAgIHNlbGYudmFsb2JqID0gdmFsb2JqCisgICAgICAgICMgRklYTUU6IEZvciBzb21lIHJl YXNvbiBsbGRiKDEpIHNvbWV0aW1lcyBoYXMgYW4gaXNzdWUgYWNjZXNzaW5nIG1lbWJlcnMgb2Yg V1RGOjpTdHJpbmdJbXBsU2hhcGUKKyAgICAgICAgIyB2aWEgYSBXVEY6OlN0cmluZ0ltcGwgcG9p bnRlciAod2h5PykuIEFzIGEgd29ya2Fyb3VuZCB3ZSBleHBsaWNpdGx5IGNhc3QgdG8gV1RGOjpT dHJpbmdJbXBsU2hhcGUqLgorICAgICAgICBzdHJpbmdfaW1wbF9zaGFwZV9wdHJfdHlwZSA9IHZh bG9iai5HZXRUYXJnZXQoKS5GaW5kRmlyc3RUeXBlKCdXVEY6OlN0cmluZ0ltcGxTaGFwZScpLkdl dFBvaW50ZXJUeXBlKCkKKyAgICAgICAgc2VsZi52YWxvYmogPSB2YWxvYmouQ2FzdChzdHJpbmdf aW1wbF9zaGFwZV9wdHJfdHlwZSkKIAogICAgIGRlZiBnZXRfbGVuZ3RoKHNlbGYpOgogICAgICAg ICByZXR1cm4gc2VsZi52YWxvYmouR2V0Q2hpbGRNZW1iZXJXaXRoTmFtZSgnbV9sZW5ndGgnKS5H ZXRWYWx1ZUFzVW5zaWduZWQoMCkKIAogICAgIGRlZiBnZXRfZGF0YTgoc2VsZik6Ci0gICAgICAg IHJldHVybiBzZWxmLnZhbG9iai5HZXRDaGlsZEF0SW5kZXgoMCkuR2V0Q2hpbGRBdEluZGV4KDIp LkdldENoaWxkTWVtYmVyV2l0aE5hbWUoJ21fZGF0YTgnKQorICAgICAgICByZXR1cm4gc2VsZi52 YWxvYmouR2V0Q2hpbGRBdEluZGV4KDIpLkdldENoaWxkTWVtYmVyV2l0aE5hbWUoJ21fZGF0YTgn KQogCiAgICAgZGVmIGdldF9kYXRhMTYoc2VsZik6Ci0gICAgICAgIHJldHVybiBzZWxmLnZhbG9i ai5HZXRDaGlsZEF0SW5kZXgoMCkuR2V0Q2hpbGRBdEluZGV4KDIpLkdldENoaWxkTWVtYmVyV2l0 aE5hbWUoJ21fZGF0YTE2JykKKyAgICAgICAgcmV0dXJuIHNlbGYudmFsb2JqLkdldENoaWxkQXRJ bmRleCgyKS5HZXRDaGlsZE1lbWJlcldpdGhOYW1lKCdtX2RhdGExNicpCiAKICAgICBkZWYgdG9f c3RyaW5nKHNlbGYpOgogICAgICAgICBlcnJvciA9IGxsZGIuU0JFcnJvcigpCg==