deps: update V8 to 7.9

[targos]

Chrome release date: Dec 10th, 2019

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/26090/
V8: https://ci.nodejs.org/job/node-test-commit-v8-linux/2559/

[targos]

11:31:00 ../deps/v8/src/base/macros.h:236:33: error: 'is_trivially_copyable' is not a member of 'std'
11:31:00    static constexpr bool value = std::is_trivially_copyable<T>::value;
11:31:00                                  ^

This error is concerning. If I'm reading the documentation correctly, this was added in C++17.

@nodejs/v8 according to https://chromium-cpp.appspot.com/, C++17 is not yet supported in Chromium. Is it going to change soon?

[psmarshall]

@backes Maybe you have an idea

[backes]

The documentation you link sais: (since C++11)
Note that v8 requires C++14 now, which should be supported by all toolchains we care about (including node).

[gengjiawen]

on macOS, https://ci.nodejs.org/job/node-test-commit-osx/nodes=osx1011/29417/console

17:19:10 ../deps/v8/src/compiler/serializer-for-background-compilation.cc:390:12: error: constructor for 'v8::internal::compiler::Callee' must explicitly initialize the const member 'blueprint_'
17:19:10   explicit Callee(Handle<JSFunction> jsfunction) : jsfunction_(jsfunction) {}
17:19:10            ^
17:19:10 ../deps/v8/src/compiler/serializer-for-background-compilation.cc:415:43: note: 'blueprint_' declared here
17:19:10   base::Optional<FunctionBlueprint> const blueprint_;
17:19:10                                           ^
17:19:10 ../deps/v8/src/compiler/serializer-for-background-compilation.cc:391:12: error: constructor for 'v8::internal::compiler::Callee' must explicitly initialize the const member 'jsfunction_'
17:19:10   explicit Callee(FunctionBlueprint const& blueprint) : blueprint_(blueprint) {}
17:19:10            ^
17:19:10 ../deps/v8/src/compiler/serializer-for-background-compilation.cc:414:33: note: 'jsfunction_' declared here
17:19:10   MaybeHandle<JSFunction> const jsfunction_;

[targos]

@backes there is this thing in the documentation:

but maybe it's not what is being used here, I'm not able to tell

[addaleax]

@targos No, V8 is only using the C++11 variant (is_trivially_copyable, not is_trivially_copyable_v).

I think the macros.h header may just be missing an #include <type_traits>.

[backes]

@addaleax Ack, but I would vote for putting that header in the file that uses base::is_trivially_copyable instead.
Can you point me to the exact error output, so I can create a CL on v8's side? Or you just create one and send it to me for review.

[targos]

the error comes from this job: https://ci.nodejs.org/job/node-test-commit-v8-linux/2559/nodes=benchmark,v8test=v8test/console

11:31:00 In file included from ../deps/v8/src/base/lazy-instance.h:73:0,
11:31:00                  from ../deps/v8/src/base/platform/condition-variable.h:9,
11:31:00                  from ../deps/v8/src/libplatform/default-foreground-task-runner.h:13,
11:31:00                  from ../deps/v8/src/libplatform/default-foreground-task-runner.cc:5:
11:31:00 ../deps/v8/src/base/macros.h:236:33: error: 'is_trivially_copyable' is not a member of 'std'
11:31:00    static constexpr bool value = std::is_trivially_copyable<T>::value;
11:31:00                                  ^
11:31:00 ../deps/v8/src/base/macros.h:236:33: note: suggested alternative:
11:31:00 In file included from ../deps/v8/src/base/lazy-instance.h:73:0,
11:31:00                  from ../deps/v8/src/base/platform/condition-variable.h:9,
11:31:00                  from ../deps/v8/src/libplatform/default-foreground-task-runner.h:13,
11:31:00                  from ../deps/v8/src/libplatform/default-foreground-task-runner.cc:5:
11:31:00 ../deps/v8/src/base/macros.h:209:8: note:   'v8::base::is_trivially_copyable'
11:31:00  struct is_trivially_copyable {
11:31:00         ^
11:31:00 In file included from ../deps/v8/src/base/lazy-instance.h:73:0,
11:31:00                  from ../deps/v8/src/base/platform/condition-variable.h:9,
11:31:00                  from ../deps/v8/src/libplatform/default-foreground-task-runner.h:13,
11:31:00                  from ../deps/v8/src/libplatform/default-foreground-task-runner.cc:5:
11:31:00 ../deps/v8/src/base/macros.h:236:61: error: expected primary-expression before '>' token
11:31:00    static constexpr bool value = std::is_trivially_copyable<T>::value;
11:31:00                                                              ^
11:31:00 ../deps/v8/src/base/macros.h:236:62: error: '::value' has not been declared
11:31:00    static constexpr bool value = std::is_trivially_copyable<T>::value;
11:31:00                                                               ^
11:31:00 make[2]: *** [/home/iojs/build/workspace/node-test-commit-v8-linux/nodes/benchmark/v8test/v8test/out/Release/obj.target/v8_libplatform/deps/v8/src/libplatform/default-foreground-task-runner.o] Error 1

[backes]

Ok, looking into macros.h, we really use more type traits internally there. I created a CL to include <type_traits> in macros.h: https://crrev.com/c/1868622

[targos]

Thanks!

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/26095/
V8: https://ci.nodejs.org/job/node-test-commit-v8-linux/2561/

[targos]

So, this isn't enough to make it work in our CI

@nodejs/build : could you please check the compiler version on the machine used here: https://ci.nodejs.org/job/node-test-commit-v8-linux/2561/nodes=benchmark,v8test=v8test/console

./configure says it's too old:

17:58:00 + ./configure
17:58:02 Node configure: Found Python 2.7.6...
17:58:02 WARNING: C++ compiler too old, need g++ 6.3.0 or clang++ 8.0.0 (CXX=g++)

[richardlau]

So, this isn't enough to make it work in our CI

@nodejs/build : could you please check the compiler version on the machine used here: https://ci.nodejs.org/job/node-test-commit-v8-linux/2561/nodes=benchmark,v8test=v8test/console

./configure says it's too old:

17:58:00 + ./configure
17:58:02 Node configure: Found Python 2.7.6...
17:58:02 WARNING: C++ compiler too old, need g++ 6.3.0 or clang++ 8.0.0 (CXX=g++)

Don't know what version is on the build machine but I've PR'ed a change to configure so we don't have to work it out next time: #30028

[rvagg]

Wait, configure says that clang 8.0.0 is a minimum but that's not documented in BUILDING.md, as far as I can tell, configure is the only place this is documented.

I'm trying to work out whether to knock out FreeBSD from >=13.x or >=14.x, it only comes with clang 6.0.0 but our docs say FreeBSD >=11 is supported.

I think this means we should just exclude FreeBSD from >=14.x but maybe this is going to be bnackported to 13.x in which case we should probably be prepared now. Does someone want to get BUILDING.md into better shape wrt clang and also probably FreeBSD while you're at it?

[richardlau]

Wait, configure says that clang 8.0.0 is a minimum but that's not documented in BUILDING.md, as far as I can tell, configure is the only place this is documented.

It was bumped up to 8.0.0 (previously 3.4.2) for Node.js 12 to match the LLVM version in XCode 8 for macOS: #26719 (comment)

[backes]

re std::is_trivially_copyable:
This standard library function was not supported in the stdlibc++ 4.8, see https://gcc.gnu.org/onlinedocs/gcc-4.8.3/libstdc++/manual/manual/status.html#status.iso.2011.
We remove support for gcc <5 in this CL: https://crrev.com/c/1786283

Since node requires GCC 6.3, this shouldn't be a problem though. Except if some bot is using an unsupported GCC version.