On Tuesday, May 16, 2017 at 9:05:41 PM UTC+8, Camillo Bruni wrote: > > FYI, the code in src/builtin/builtin-*-gen.cc is no longer shipped and > is neither performance critical as it is only used to create the code stubs > for the snapshot. >
I am aware of that. I noted that in one comment of the CL, but forgot to re-mention it again in this thread. src/runtime/runtime-regexp.cc and other codes also use a bit of std::function + lambda, so this refactoring will still benefit snapshot build slightly. By the way, Official Node.js binary is built with snapshot or nosnaphot configuration? > > On Tue, May 16, 2017 at 2:52 PM <[email protected] <javascript:>> wrote: > >> On Tuesday, May 16, 2017 at 8:34:43 PM UTC+8, Jochen Eisinger wrote: >>> >>> Thanks for the summary! >>> >>> I'm wondering whether you also plan other refactoring work for V8? >>> >> >> No, I only have plan for this refactoring for now. >> >> >>> >>> Also, why not just import base::Bind and friends from Chromium? >>> >> >> Chromium's implementation uses many other Chromium-specific features like >> weak_ptr<>, we might end up introducing more code than V8 actually needs. >> As far as I can see, CodeAssemblerCallback seems to be the only use case of >> std::function that might benefit from Chromium's Callable<>. >> >> >>> >>> On Tue, May 16, 2017 at 2:04 PM <[email protected]> wrote: >>> >>>> Hi V8 devs, >>>> >>>> I saw a few functions in src/builtin/builtin-*-gen.cc and >>>> src/code-stub-assembler.h uses quite a few std::function as a parameter, >>>> then pass lambda function to these functions to avoid code duplication as >>>> much as possible. std::function was used because raw function pointer >>>> can't >>>> accept lambda function. >>>> >>>> However, because std::function is really powerful, it comes with a cost >>>> in terms of code size and overhead when calling std::function. >>>> >>>> I am working on introducing function_view to src/base, a lightweight >>>> callable reference that can accept normal and lambda function. >>>> >>>> function_view is adapted from [1] >>>> <https://vittorioromeo.info/index/blog/passing_functions_to_functions.html>. >>>> >>>> I have changed it so that it can be compiled with C++11, which is the >>>> minimum compiler support requirement to build Chromium. >>>> >>>> Note: >>>> >>>> The callable itself must be alive longer or equal to the life time of >>>> function_view object. Therefore, function_view is not a universal >>>> replacement for the general-purpose std::function. >>>> >>>> If you need to store lambda function as class property, std::function >>>> is still needed. Use case like [2] >>>> <https://cs.chromium.org/chromium/src/v8/src/compiler/code-assembler.h?type=cs&l=601> >>>> >>>> cannot be replaced with function_view. >>>> >>>> Chromium do have a very powerful library to store callback at >>>> https://cs.chromium.org/chromium/src/base/bind_internal.h >>>> (std::function is banned in Chromium). >>>> >>>> Plan: >>>> >>>> - Add base::function_view implementation to src/base/functional.h >>>> - Convert std::function to base::function_view in >>>> src/builtin/builtin-*-gen.cc and maybe other parts of src/* if >>>> appropriate. >>>> Usage of std::function in test/* will be ignored. >>>> - Add documentation. >>>> - Add unittest. >>>> >>>> src/compiler/s390/instruction-selector-s390.cc also uses a lot of >>>> std::function + lambda, but because I can't test on this platform myself, >>>> I >>>> don't feel safe to change it. It looks like dry run does not have bot for >>>> s390. >>>> >>>> WIP CL: >>>> >>>> https://chromium-review.googlesource.com/c/505653/ >>>> >>>> [1]: >>>> https://vittorioromeo.info/index/blog/passing_functions_to_functions.html >>>> [2]: >>>> https://cs.chromium.org/chromium/src/v8/src/compiler/code-assembler.h?type=cs&l=601 >>>> >>>> Sincerely, >>>> Rong Jie >>>> >>> -- >> -- >> v8-dev mailing list >> [email protected] <javascript:> >> http://groups.google.com/group/v8-dev >> --- >> You received this message because you are subscribed to the Google Groups >> "v8-dev" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > -- > Camillo Bruni | Software Engineer, V8 | Google Germany GmbH | Erika-Mann > Str. 33, 80636 München > Registergericht und -nummer: Hamburg, HRB 86891 | Sitz der Gesellschaft: > Hamburg | Geschäftsführer: Matthew Scott Sucherman, Paul Terence Manicle > -- -- v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
