That's a surprisingly tricky thing to do, despite sounding simple. You could add a new runtime function (e.g. LogComparison) which you call at the beginning of CodeStubAssembler::Equal, passing it the LHS and RHS. A bigger cannon that you could use on this mosquito is to enable ignition tracing (v8_enable_trace_ignition = true in gn args) and run your code with `--no-opt --trace-ignition`, which will print a line for every bytecode executed that you can then grep through.
On Mon, Mar 4, 2019 at 4:52 PM <examm...@gmail.com> wrote: > Thanks > > in fact what i want to do is to log all comparisons at excecution. What is > the best way to do that ? > > Le lundi 4 mars 2019 13:15:53 UTC+1, Leszek Swirski a écrit : >> >> --force-slow-path is a bit confusing, and maybe not well named, I believe >> it only affects some builtins (regex etc.) >> >> For some more detail, a lot of functionality in V8 is implemented >> multiple times -- common, simpler fast paths (e.g. comparing numbers as you >> are) are implemented in "assembly" (which used to be actual machine code, >> now it's mostly CSA <https://v8.dev/docs/csa-builtins> or Torque >> <https://v8.dev/docs/torque-builtins> code), less common "slow" paths >> (e.g. comparing BigInts) will go to the "runtime" (i.e. into the C++ code). >> These runtime functions also have fast and slow paths (which are really >> more like medium speed and extra slow), and the flag you mentioned is for >> forcing those slow paths. >> >> For specifically comparison, you probably want to hook into >> CodeStubAssembler::Equal >> <https://cs.chromium.org/chromium/src/v8/src/code-stub-assembler.cc?type=cs&q=CodeStubAssembler::Equal&sq=package:chromium&g=0&l=11680>, >> though keep in mind that the linked code is *generating* the comparison >> code, not *calculating* or executing it. You'll also want to disable >> optimisation (--no-opt) to make sure you don't enter optimized code (which >> inlines the comparison). >> >> - Leszek >> >> On Mon, Mar 4, 2019 at 9:49 AM <exam...@gmail.com> wrote: >> >>> I have tried to add --force-slow-path argument and it does not change >>> anything >>> >>> Le lundi 4 mars 2019 08:56:09 UTC+1, exam...@gmail.com a écrit : >>>> >>>> Thanks >>>> >>>> What do you mean by 'slow path' ? >>>> Where should i put some code in order to hook comparisons operators ? >>>> >>> -- >>> -- >>> v8-dev mailing list >>> v8-...@googlegroups.com >>> 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 v8-dev+un...@googlegroups.com. >>> For more options, visit https://groups.google.com/d/optout. >>> >> -- > -- > v8-dev mailing list > v8-dev@googlegroups.com > 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 v8-dev+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- -- v8-dev mailing list v8-dev@googlegroups.com 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 v8-dev+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
