Thank again Jakob. > Of course you can also use a debugger of your choice, interrupt the > program when it's in the state you want to inspect, and start disassembling > whatever you're interested in. > Actually, I can't use print function in gdb with d8. I compile v8 in debug mode. What should I do to provide debug symbols in full-codegen in other v8 parts? On Tuesday, February 16, 2016 at 3:50:01 PM UTC+6, Jakob Kummerow wrote: > > On Tue, Feb 16, 2016 at 10:38 AM, <[email protected] <javascript:>> wrote: > >> 1) 0x36c28f53eecf 47 e8cc92fdff call 0x36c28f5181a0 ;; code: >> contextual, LOAD_IC, GENERIC >> Who does generate this stub? Full-codegen? >> > > No, the IC system. You can start reading in LoadIC::Load in src/ic/ic.cc > and trace your way to the various HandlerCompilers, but be warned: there's > a lot of complexity there. > > >> 2) As I undertood the effictive code is placed in IC stub? >> > > Depends on what you mean by "effective code". Originally you said you > wanted to understand full codegen. Stubs are not part of full codegen. > > >> If this is true then where can I see the stub's code? >> > > --print-code-stubs. However, for this specific example, you won't see a > stub there, because loading properties from numbers is handled specially. > > Of course you can also use a debugger of your choice, interrupt the > program when it's in the state you want to inspect, and start disassembling > whatever you're interested in. > > >> On Tuesday, February 16, 2016 at 3:18:07 PM UTC+6, Jakob Kummerow wrote: >> >>> On Tue, Feb 16, 2016 at 10:08 AM, <[email protected]> wrote: >>> >>>> Thank Jakob. >>>> >>>> Consider much more easier function: >>>> >>>> >>>> function foo(o) { >>>> return o.x; >>>> } >>>> >>>> >>>> print(foo(37)); >>>> >>>> >>>> listing <http://pastebin.com/u0ZM8C3w> >>>> >>>> I've got two question: >>>> 1) 0x36c28f53eecf 47 e8cc92fdff call 0x36c28f5181a0 ;; >>>> code: contextual, LOAD_IC, GENERIC >>>> Does that code create new IC stub? Where is the check for IC placed? >>>> >>> >>> That's the call to the IC stub. The stub is created elsewhere >>> (dynamically, as needed). All the type checks happen inside the stub, not >>> in the enclosing function. >>> >>> >>>> >>>> I believe that check should looks like: >>>> if (actual_type1 == int) -> generate IC stub for int, if it exists then >>>> we call it >>>> if (actual_type1 == double) ... >>>> >>> >>> More like: >>> if (hidden class of o == previously seen hidden class) { call previously >>> generated handler } >>> else miss /* call into C++ to create a new handler for the new hidden >>> class */ >>> >>> At least that's the standard "monomorphic" case. The IC system is quite >>> flexible, each IC can be in one of many different states. >>> >>> >>>> 2) How to remove lines that looks like debug *. For example : debug: >>>> statement 19 >>>> >>> >>> They're just comments, part of the --code-comments output. Their purpose >>> is to make it easier for you to trace machine instructions back to the >>> JavaScript source. >>> >>> >>>> On Tuesday, February 16, 2016 at 2:31:58 PM UTC+6, Jakob Kummerow wrote: >>>>> >>>>> On Tue, Feb 16, 2016 at 8:10 AM, <[email protected]> wrote: >>>>> >>>>>> Thank Ben, but I need to some example: >>>>>> >>>>>> function add(a, b) { >>>>>> return a + b; >>>>>> } >>>>>> >>>>>> >>>>>> print(add(37, 73)); >>>>>> I execute this code via d8. >>>>>> >>>>>> What is context in that case? >>>>>> >>>>> >>>>> Your function "add" is so simple that it doesn't need a context, and >>>>> indeed no context is allocated. >>>>> >>>>> >>>>>> I've got the asm listing via --print-code: listing >>>>>> <http://pastebin.com/NhWyhRDK> >>>>>> Actually I can't understand why the listing consists so many codes? >>>>>> The adder function is very simple. >>>>>> >>>>>> 0xda955b3eff6 150 49ba0000000025000000 REX.W movq r10,0x2500000000 >>>>>> 0xda955b3f000 160 4152 push r10 >>>>>> 0xda955b3f002 162 49ba0000000049000000 REX.W movq r10,0x4900000000 >>>>>> 0xda955b3f00c 172 4152 push r10 >>>>>> 0xda955b3f00e 174 48ba0000000007000000 REX.W movq rdx,0x700000000 >>>>>> 0xda955b3f018 184 488b7c2418 REX.W movq rdi,[rsp+0x18] >>>>>> 0xda955b3f01d 189 e85efcffff call 0xda955b3ec80 ;; code: >>>>>> CALL_IC, GENERIC >>>>>> 0xda955b3f022 194 488b75f8 REX.W movq rsi,[rbp-0x8] >>>>>> 0xda955b3f026 198 48890424 REX.W movq [rsp],rax >>>>>> >>>>>> >>>>> ^ That's the compiled top-level code. The compiled code for function >>>>> "add" is in lines 109 - 170 in your pastebin. You can tell either by >>>>> looking at the "--- Raw source ---" section, or at the "name = add" line. >>>>> >>>>> If you run with --code-comments, you'll get comments embedded into the >>>>> code that'll explain what each section was generated for. >>>>> >>>>> >>>>>> On Monday, February 15, 2016 at 11:14:58 PM UTC+6, Ben Noordhuis >>>>>> wrote: >>>>>> >>>>>>> On Mon, Feb 15, 2016 at 1:57 PM, <[email protected]> wrote: >>>>>>> > Hi all! >>>>>>> > >>>>>>> > I'm trying to understand the full-codegen compiler in v8. >>>>>>> > >>>>>>> > Ok, I've taken the full-codegen code for x64 architecture. >>>>>>> > >>>>>>> > As I can see in code, it does following things: >>>>>>> > Build x64 frame >>>>>>> > Allocate locals >>>>>>> > And then allocate context <- this is magic for me >>>>>>> > >>>>>>> > The code's: >>>>>>> > >>>>>>> > // Possibly allocate a local context. >>>>>>> > >>>>>>> > if (info->scope()->num_heap_slots() > 0) { >>>>>>> > >>>>>>> > Comment cmnt(masm_, "[ Allocate context"); >>>>>>> > >>>>>>> > bool need_write_barrier = true; >>>>>>> > >>>>>>> > int slots = info->scope()->num_heap_slots() - >>>>>>> > Context::MIN_CONTEXT_SLOTS; >>>>>>> > >>>>>>> > // Argument to NewContext is the function, which is still in >>>>>>> rdi. >>>>>>> > >>>>>>> > ... >>>>>>> > >>>>>>> > >>>>>>> > What does the full-codegen does here? >>>>>>> >>>>>>> The context it allocates is the storage for a function's free >>>>>>> variables. V8's garbage collector is generational; the write >>>>>>> barrier >>>>>>> is for tracking object references from the old space to the new >>>>>>> space. >>>>>>> >>>>>> -- >>>>>> >>>>> -- >> -- >> 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. >> > >
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