Bug 182081

Summary:

[Win] MSVC doesn't seem to like "friend class NeverDestroyed<Foo>"

Product:

WebKit

Reporter:

Fujii Hironori <fujii.hironori>

Component:

WebKit Misc.

Assignee:

Fujii Hironori <fujii.hironori>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

achristensen, basuke, bfulgham, commit-queue, jiewen_tan, pvollan, webkit-bug-importer, Yousuke.Kimoto, ysuzuki

Priority:

Keywords:

InRadar

Version:

WebKit Nightly Build

Hardware:

Unspecified

OS:

Unspecified

Bug Depends on:

Bug Blocks:

177202

Attachments:

Description	Flags
Patch	none

Fujii Hironori

Reported 2018-01-24 18:27:44 PST

[Win] MSVC doesn't seem to like "friend class NeverDestroyed<Foo>" While trying to build WebKit2 for Windows (Bug 181885), I see a lot of compilation errors that NeverDestroyed is not a friend like following: > 1>------ Build started: Project: WebKit (WebKit\WebKit), Configuration: Debug x64 ------ > 1>NetworkProcess.cpp > 1>C:\webkit\gb\WebKitBuild\Debug\DerivedSources\ForwardingHeaders\wtf/NeverDestroyed.h(50): error C2248: 'WebKit::NetworkProcess::NetworkProcess': cannot access private member declared in class 'WebKit::NetworkProcess' > 1>C:\webkit\gb\Source\WebKit\NetworkProcess\NetworkProcess.cpp(104): note: see declaration of 'WebKit::NetworkProcess::NetworkProcess' > 1>c:\webkit\gb\source\webkit\networkprocess\NetworkProcess.h(79): note: see declaration of 'WebKit::NetworkProcess' > 1>C:\webkit\gb\Source\WebKit\NetworkProcess\NetworkProcess.cpp(100): note: see reference to function template instantiation 'WTF::NeverDestroyed<WebKit::NetworkProcess>::NeverDestroyed<>(void)' being compiled > 1>C:\webkit\gb\Source\WebKit\NetworkProcess\NetworkProcess.cpp(100): note: see reference to function template instantiation 'WTF::NeverDestroyed<WebKit::NetworkProcess>::NeverDestroyed<>(void)' being compiled > 1>Done building project "WebKit.vcxproj" -- FAILED. > ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== If I apply a following patch, it can build: > diff --git a/Source/WebKit/NetworkProcess/NetworkProcess.h b/Source/WebKit/NetworkProcess/NetworkProcess.h > index a9c9818dd03..15a7469cb23 100644 > --- a/Source/WebKit/NetworkProcess/NetworkProcess.h > +++ b/Source/WebKit/NetworkProcess/NetworkProcess.h > @@ -78,8 +78,8 @@ class Cache; > > class NetworkProcess : public ChildProcess, private DownloadManager::Client { > WTF_MAKE_NONCOPYABLE(NetworkProcess); > - friend class NeverDestroyed<NetworkProcess>; > - friend class NeverDestroyed<DownloadManager>; > + friend NeverDestroyed<NetworkProcess>; > + friend NeverDestroyed<DownloadManager>; > public: > static NetworkProcess& singleton(); >

Attachments
Patch (13.73 KB, patch) 2018-02-01 17:43 PST, Fujii Hironori	no flags	Details Formatted Diff Diff
View All Add attachment proposed patch, testcase, etc.

Fujii Hironori

Comment 1 2018-01-24 18:29:33 PST

(In reply to Fujii Hironori from comment #0) > [Win] MSVC doesn't seem to like "friend class NeverDestroyed<Foo>" > > While trying to build WebKit2 for Windows (Bug 181885), Incorrect bug id. it's Bug 177202.

Fujii Hironori

Comment 2 2018-01-24 18:52:06 PST

I can't find an answer in this page. friend declaration - cppreference.com http://en.cppreference.com/w/cpp/language/friend

Fujii Hironori

Comment 3 2018-01-24 19:22:13 PST

https://timsong-cpp.github.io/cppwp/n4140/temp.friend > template<class T> class task; > template<class T> task<T>* preempt(task<T>*); > > template<class T> class task { > friend void next_time(); > friend void process(task<T>*); > friend task<T>* preempt<T>(task<T>*); > template<class C> friend int func(C); > > friend class task<int>; > template<class P> friend class frd; > }; [...] > [...] Similarly, each specialization of the task class template has the class template specialization task<int> as a friend, [...] If I understand correctly, "friend class NeverDestroyed<Foo>" is a valid style.

Fujii Hironori

Comment 4 2018-01-24 19:26:58 PST

Specifying command line switch /std:c++14, /std:c++17 or /std:c++latest doesn't help at all. (I'm using VS 2017 version 15.5.2)

Fujii Hironori

Comment 5 2018-01-24 21:09:31 PST

Repro: <https://gist.github.com/fujii/fea40827887237053b537f48807a8963> The template friend class, which belongs to a different namespace, can't access private member if its friend declaration is specified without the namespace and with class keyword. I sent a bug report to MS compiler team.

Fujii Hironori

Comment 6 2018-01-25 18:53:37 PST

I got their reply: > Looks like this is already fixed with VS2017 15.6 preview 3. I also confirmed this problem was fixed by it.

Fujii Hironori

Comment 7 2018-02-01 17:26:57 PST

can't wait VS2017 15.6 release. reopen.

Fujii Hironori

Comment 8 2018-02-01 17:43:26 PST

Created attachment 332926 [details] Patch

Yusuke Suzuki

Comment 9 2018-02-02 09:13:40 PST

Comment on attachment 332926 [details] Patch r=me