Thanks very much, Jakob! That was immensely helpful. ~ jf
On Wednesday, October 8, 2014 12:54:33 PM UTC-4, Jakob Kummerow wrote: > > On Wed, Oct 8, 2014 at 5:56 PM, John Feminella <[email protected] <javascript:>> > wrote: > >> As an educational exercise, I'd like to inspect disassembled JS generated >> by JS, and compare both the optimized and unoptimized versions to see what >> changes and what doesn't. >> >> In Vyacheslav Egorov's JSConf 2012 excellent slides ( >> http://s3.mrale.ph/jsconf2012.pdf) he recommends compiling V8 like so: >> >> ===== >> make ia32.release objectprint=on \ >> disassembler=on >> >> out/ia32.release/d8 --print-opt-code \ >> --code-comments \ >> --trace-hydrogen \ >> test.js >> ===== >> >> which will enable the disassembler for introspection by the curious. >> >> I'm having a little trouble understanding the current state of affairs, >> though: >> >> 0. Is this the best way of doing things? How do I generate the >> *unoptimized* JS versus the *optimized* JS for test.js in this example? >> > > I guess by "optimized JS" you mean "optimized machine code". Try > "out/ia32.release/d8 > --help | grep print | grep code". You probably want "--print-opt-code > --print-unopt-code". > > 1. Are Hydrogen and Crankshaft still relevant? >> > > Yes. > > >> For example, my limited understanding is that TurboFan will be replacing >> Hydrogen: https://codereview.chromium.org/426233002 >> > > > Is there somewhere I can read about the relevance and lifecycle of >> different pieces like Hydrogen and Crankshaft and how they play a role in >> code generation/optimization? >> > > The short version is "full codegen, then Hydrogen". wingolog.org has some > more in-depth articles. > > >> 2. Why does Vyacheslav suggest using --trace-hydrogen? Is that needed to >> see the disassembly? >> > > No, it's needed for other things (c1visualizer, ir-hydra). > -- -- v8-users mailing list [email protected] http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" 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.
