Anton, can you add this to https://source.chromium.org/chromium/chromium/src/+/main:docs/linux/debugging.md ?
On Tue, Oct 11, 2022 at 10:19 AM Anton Bikineev <bikin...@chromium.org> wrote: > I'm now submitting a CL > <https://chromium-review.googlesource.com/c/v8/v8/+/3945108> that adds > some quick gdb helpers: > > (gdb) source v8/tools/gdbinit > # Print Member: > (gdb) cpm *<member-name>* > # Print Compressed Pointer: > (gdb) cpcp *<compressed-32-bit-value>* > > It currently erases the pointee type, but this can be improved in the > future. > > On Tue, Oct 11, 2022 at 4:05 PM Anton Bikineev <bikin...@chromium.org> > wrote: > >> Which should hopefully be callable from the debugger and not eliminated >>> by the linker? >> >> We can apply __attribute__((used,retain)) to make sure that the linker >> doesn't strip the functions with --gc-sections, same as did >> <https://chromium-review.googlesource.com/c/v8/v8/+/3932179> for V8 >> helpers (a week ago :) ). I'll prepare a CL. >> >> On Mon, Oct 10, 2022 at 8:45 PM Daniel Cheng <dch...@chromium.org> wrote: >> >>> For now, I guess it should be sufficient to add something >>> to v8/include/cppgc/internal/member-storage.h like >>> >>> #ifndef NDEBUG // DCHECK_IS_ON() would be nicer, but not sure what v8 >>> uses >>> extern "C" void* DecompressPointerForDebugger(uint32_t value) { >>> return cppgc::internal::CompressedPointer::Decompress(value); >>> } >>> #endif >>> >>> Which should hopefully be callable from the debugger and not eliminated >>> by the linker? >>> >>> Daniel >>> >>> On Mon, 10 Oct 2022 at 11:32, Stefan Zager <sza...@chromium.org> wrote: >>> >>>> I ran into this today, and it's pretty frustrating: >>>> >>>> (rr) p inner_node_ >>>> >>>> $11 = { >>>> >>>> <cppgc::internal::MemberBase> = { >>>> >>>> raw_ = { >>>> >>>> static kCompressedSentinel = 1, >>>> >>>> value_ = 2148082696 <(214)%20808-2696> >>>> >>>> } >>>> >>>> }, >>>> >>>> <cppgc::internal::DisabledCheckingPolicy> = {<No data fields>}, <No >>>> data fields>} >>>> (rr) p inner_node_.Load() >>>> >>>> Couldn't find method blink::Member<blink::Node>::Load >>>> >>>> (rr) p inner_node_.raw_.Load() >>>> >>>> Cannot evaluate function -- may be inlined >>>> >>>> (rr) p >>>> cppgc::internal::CompressedPointer::Decompress(inner_node_.raw_.value_) >>>> >>>> Cannot evaluate function -- may be inlined >>>> >>>> (rr) >>>> >>>> I found that I can avoid the issue with this in args.gn: >>>> >>>> cppgc_enable_caged_heap = false >>>> cppgc_enable_pointer_compression = false >>>> >>>> ... but I would prefer a better solution. >>>> >>>> On Mon, Oct 10, 2022 at 10:22 AM Ian Kilpatrick < >>>> ikilpatr...@chromium.org> wrote: >>>> >>>>> Is there a bug to follow regarding the debuggability of the pointers? >>>>> >>>>> Ian >>>>> >>>>> On Thu, Sep 22, 2022 at 11:10 AM Anton Bikineev <bikin...@chromium.org> >>>>> wrote: >>>>> >>>>>> There is "cppgc::internal::CompressedPointer::Decompress(void*)". I >>>>>> would, however, hide it behind a simpler name in .gdbinit. >>>>>> >>>>>> On Thu, Sep 22, 2022 at 5:51 PM Daniel Cheng <dch...@chromium.org> >>>>>> wrote: >>>>>> >>>>>>> Is there a callable C++ function that can turn a compressed pointer >>>>>>> into the actual pointer value? >>>>>>> >>>>>>> Daniel >>>>>>> >>>>>>> On Thu, 22 Sept 2022 at 08:43, Anton Bikineev <bikin...@chromium.org> >>>>>>> wrote: >>>>>>> >>>>>>>> We have plans to provide more debugging tooling for Oilpan. I >>>>>>>> haven't had a need to examine compressed pointers myself, however I see >>>>>>>> that some simple gdb/windbg function that'd follow pointers would be >>>>>>>> useful. >>>>>>>> >>>>>>>> On Thu, Sep 22, 2022 at 1:14 AM Kentaro Hara <hara...@chromium.org> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> +Michael Lippautz <mlippa...@chromium.org> >>>>>>>>> >>>>>>>>> 2022年9月22日(木) 4:01 'Daniel Libby' via blink-dev < >>>>>>>>> blink-dev@chromium.org>: >>>>>>>>> >>>>>>>>>> https://crrev.com/c/3835682 enabled pointer compression for >>>>>>>>>> Blink Member<> pointers. How are folks handling these while >>>>>>>>>> debugging (either live or crash dumps)? Is there some tooling >>>>>>>>>> available >>>>>>>>>> that will look up and apply the cage base? >>>>>>>>>> >>>>>>>>>> I didn't see anything mentioned in >>>>>>>>>> https://docs.google.com/document/d/1neGN8Jq-1JLrWK3cvwRIfrSjLgE0Srjv-uq7Ze38Iao/edit# >>>>>>>>>> but maybe there are better known tools/techniques from v8 (which >>>>>>>>>> IIUC has >>>>>>>>>> had compressed pointers for some time now). >>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> You received this message because you are subscribed to the >>>>>>>>>> Google Groups "blink-dev" group. >>>>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>>>> send an email to blink-dev+unsubscr...@chromium.org. >>>>>>>>>> To view this discussion on the web visit >>>>>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/4b3e5bbb-134a-4483-9a1e-8e33fbc6f38en%40chromium.org >>>>>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/4b3e5bbb-134a-4483-9a1e-8e33fbc6f38en%40chromium.org?utm_medium=email&utm_source=footer> >>>>>>>>>> . >>>>>>>>>> >>>>>>>>> -- >>>>>>>>> You received this message because you are subscribed to the Google >>>>>>>>> Groups "blink-dev" group. >>>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>>> send an email to blink-dev+unsubscr...@chromium.org. >>>>>>>>> To view this discussion on the web visit >>>>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABg10jxSdx3JzWvTC2j7RUEcw01P9gTRhT%3DnftwehY3br4qNWA%40mail.gmail.com >>>>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABg10jxSdx3JzWvTC2j7RUEcw01P9gTRhT%3DnftwehY3br4qNWA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>>>>> . >>>>>>>>> >>>>>>>> -- >>>>>>>> You received this message because you are subscribed to the Google >>>>>>>> Groups "blink-dev" group. >>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>> send an email to blink-dev+unsubscr...@chromium.org. >>>>>>>> To view this discussion on the web visit >>>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABH6udYH6VGy8Ooz6ZLZWpWR_LjjQfu1xh-AMBvWoyAnArojbA%40mail.gmail.com >>>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABH6udYH6VGy8Ooz6ZLZWpWR_LjjQfu1xh-AMBvWoyAnArojbA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>>>> . >>>>>>>> >>>>>>> -- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "blink-dev" group. >>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>> send an email to blink-dev+unsubscr...@chromium.org. >>>>>> To view this discussion on the web visit >>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABH6udZS_4iw6Vhb%3Dtf0J9qgV%3DbwbcWAu%2B--Xt9dYrDpqDecXw%40mail.gmail.com >>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABH6udZS_4iw6Vhb%3Dtf0J9qgV%3DbwbcWAu%2B--Xt9dYrDpqDecXw%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>> . >>>>>> >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "blink-dev" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to blink-dev+unsubscr...@chromium.org. >>>>> To view this discussion on the web visit >>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAJL3UpQ%2BiPOAMX6ONDxRm9UG0zFRkScw1%3DdALFGdKJOUiAUpEw%40mail.gmail.com >>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAJL3UpQ%2BiPOAMX6ONDxRm9UG0zFRkScw1%3DdALFGdKJOUiAUpEw%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> -- > You received this message because you are subscribed to the Google Groups > "blink-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to blink-dev+unsubscr...@chromium.org. > To view this discussion on the web visit > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABH6udZ7rMMqmsZ98RbS21yG_DBXXtnoOVYnO4oV%3Dno3tFvNug%40mail.gmail.com > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABH6udZ7rMMqmsZ98RbS21yG_DBXXtnoOVYnO4oV%3Dno3tFvNug%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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