src: slim down node_v8_platform-inl.h

[lilsweetcaligula]

De-inline and move big functions from node_v8_platform-inl.h to help reduce the binary size.

Non-functional change.

Refs: #43712

[lilsweetcaligula]

Method definitions like this - wherein a method is non-inline if NODE_USE_V8_PLATFORM but inline otherwise - have been intentionally kept in the .h file, as opposed to moving them to a .cc file.

The idea being - to prevent confusion and mistakes due to code duplication of the NODE_USE_V8_PLATFORM if-else construct, e.g.:

// src/node_v8_platform.h

class NodeTraceStateObserver {

#if NODE_USE_V8_PLATFORM
  void Initialize(int thread_pool_size);
#else
  inline void Initialize(int thread_pool_size);
#endif // NODE_USE_V8_PLATFORM

}

// src/node_v8_platform.cc

#if NODE_USE_V8_PLATFORM
void NodeTraceStateObserver::Initialize(int thread_pool_size) {
  // ...
}
#else
inline void NodeTraceStateObserver::Initialize(int thread_pool_size) {
  // ...
}
#endif // NODE_USE_V8_PLATFORM

[lilsweetcaligula]

Ran the cpp linter. My bad for force-pushing.

[bnoordhuis]

Moving code from foo-inl.h file to foo.h doesn't fix the code bloat problem. In fact, it probably makes it worse because foo.h is normally included more often than foo-inl.h.

The goal of #43712 is to move method definitions that are too big/infrequently called/etc. from foo.h or foo-inl.h to foo.cc.

[lilsweetcaligula]

@bnoordhuis
Noted, thank you for taking a look. I have proceeded to extract the definitions of the de-inlined functions into a separate .cc file (pushed the commit for reference). However upon comparing the binary size (i.e. du ./out/Release/node) against the main branch, I have realized that the size did not change. As such, is it correct to assume that it makes no sense to proceed with further refactoring of node_v8_platform-inl.h? (And you are correct, - turns out, before the extraction the size was even 4 bytes bigger, yikes...)

Generally speaking, should binary size be the "go-to" litmus test when evaluating usefulness of this kind of refactor? My C++ is a bit rusty but I intend to continue working on #43712 to completion.

[bnoordhuis]

Yes, binary size is the decisive criterion. If moving code from a .h to a .cc makes no meaningful difference, then it likely means that code is not called from many places; there are probably just one or two call sites.

I'm 85% sure that applies to node_v8_platform-inl.h. Most includes of that file could probably be switched to node_v8_platform.h to no ill effect.

[lilsweetcaligula]

@bnoordhuis Noted. Thank you. Closing the PR.