On Wed, Oct 8, 2014 at 5:56 PM, John Feminella <j...@jxf.me> 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 v8-users@googlegroups.com 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 v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
