[Mono-dev] [PATCH] more support for Google Native Client

Zoltan Varga vargaz at gmail.com
Thu Jan 6 05:34:58 EST 2011


Hi,

  I merged your changes to mono's master except for the following:
runtime/mono-wrapper.in
mono/mini/genmdesc.c
nacl/

                               Zoltan

On Thu, Jan 6, 2011 at 2:22 AM, Elijah Taylor <elijahtaylor at google.com>wrote:

> Ok, I'll check out the changes/info you mentioned and go through the files
> that auto-merged, too.  Probably won't get this done for at least a day or
> so, but I'll rebase again once I've fixed it.  Hopefully by that point
> something else won't have broken too :)
>
> -Elijah
>
>
> On Wed, Jan 5, 2011 at 5:19 PM, Zoltan Varga <vargaz at gmail.com> wrote:
>
>> Hi,
>>
>>   This should work as follows: every aot image contains a MonoAotFileInfo
>> structure,
>> emitted in emit_file_info () in aot-compiler.c,  which has a 'flags'
>> field, and the MONO_AOT_FILE_FLAG_FULL_AOT flag should be set in
>> this field. At runtime, check_usable() in aot-runtime.c checks this flag.
>>
>>                         Zoltan
>>
>> On Thu, Jan 6, 2011 at 2:10 AM, Zoltan Varga <vargaz at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> On Thu, Jan 6, 2011 at 1:24 AM, Elijah Taylor <elijahtaylor at google.com>wrote:
>>>
>>>> Zoltan,
>>>>
>>>> I've rebased from mono's master branch and fixed all merge conflicts,
>>>> but something that's gone in since I first forked has now broken NaCl AOT
>>>> compilation for me.  On amd64 the compiler just crashes and I'm looking into
>>>> that, nut on x86 I'm getting this: Can't use AOT image 'mscorlib' in
>>>> aot-only mode because it is not compiled with --aot=full. But I'm
>>>> compiling with --aot=full,static,nodebug,ntrampolines=4096
>>>>
>>>> If need be I can pick through the AOT changes that have gone in, but I
>>>> was hoping you or someone on this list would be able to tell me the major
>>>> changes to AOT from the past 3 weeks and some ideas about what might be
>>>> getting in my way.  Can you shed any light?
>>>>
>>>>
>>> There was a big reorganization in the AOT file format to reduce the
>>> number of global symbols exported from the aot images. No idea why this is
>>> causing problems. make fullaotcheck and make fsacheck still seems to work
>>> for me on x86. I fixed a uninitilized memory error in 88d676ffd425def3,
>>> maybe that will help.
>>>
>>>                                     Zoltan
>>>
>>>>  -Elijah
>>>>
>>>>
>>>>
>>>> On Wed, Jan 5, 2011 at 3:51 PM, Zoltan Varga <vargaz at gmail.com> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>>   I think the current code looks ok, and we should think about how to
>>>>> merge it into mono trunk. As a first step, could you rebase your master
>>>>> branch on top of master to fix the few conflicts which has surfaced due to
>>>>> changes to mono master ?
>>>>>
>>>>>                  Zoltan
>>>>>
>>>>> On Wed, Jan 5, 2011 at 8:23 PM, Elijah Taylor <elijahtaylor at google.com
>>>>> > wrote:
>>>>>
>>>>>> Hi Zoltan,
>>>>>>
>>>>>> I've addressed all of the issues you pointed out (minus genmdesc.c:
>>>>>> __nacl_suspend_thread_if_needed, but that doesn't need to be merged in at
>>>>>> this time, it can remain in my local repository only).  Please take another
>>>>>> look at your earliest convenience and let me know if there's anything else
>>>>>> you need from me.
>>>>>>
>>>>>> -Elijah
>>>>>>
>>>>>>
>>>>>> On Tue, Jan 4, 2011 at 10:55 AM, Elijah Taylor <
>>>>>> elijahtaylor at google.com> wrote:
>>>>>>
>>>>>>> Replies inline:
>>>>>>>
>>>>>>> On Tue, Jan 4, 2011 at 10:30 AM, Zoltan Varga <vargaz at gmail.com>wrote:
>>>>>>>
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>>   Some comments:
>>>>>>>> - the patch changes IMT_REG to AMD64_R11 in the non-nacl case, I'm
>>>>>>>> not sure thats
>>>>>>>>   intentional.
>>>>>>>>
>>>>>>>
>>>>>>> Has this changed in the last six months on the Mono side?  IIRC I
>>>>>>> didn't mean to change anything like this.  The reason I made explicit
>>>>>>> defines was so code in aot-compiler and mini-amd64 could share defines over
>>>>>>> which reg was the one we jump through and which was a scratch reg.  I'll
>>>>>>> diff vs Mono head revision and make it correct.
>>>>>>>
>>>>>>>
>>>>>>>> - you could define __mono_ilp32__ in the nacl/amd64 case, and use
>>>>>>>> that instead of
>>>>>>>>   defined(__native_client_codegen__) && defined(TARGET_AMD64) in a
>>>>>>>> few places.
>>>>>>>>
>>>>>>>
>>>>>>> That sounds reasonable.  I'm assuming you mean non-arch specific
>>>>>>> areas like mini.c, aot-*.c, method-to-ir.c, etc?  Are there any other major
>>>>>>> consequences to defining __mono_ilp32__ ?
>>>>>>>
>>>>>>>
>>>>>>>> - it would be better to define nacl_global_codeman_validate () as a
>>>>>>>> no-op in the non-nacl case, so its callers wouldn't need #ifdefs.
>>>>>>>>
>>>>>>>
>>>>>>> I'll fix this.
>>>>>>>
>>>>>>>
>>>>>>>> - genmdesc.c contains this change, which is probably not needed:
>>>>>>>> +void __nacl_suspend_thread_if_needed() {}
>>>>>>>> +
>>>>>>>>
>>>>>>>
>>>>>>> It is needed temporarily due to a preliminary GC implementation, we
>>>>>>> don't have to submit it this way.  Eventually (soon) we won't need it at
>>>>>>> all.
>>>>>>>
>>>>>>>
>>>>>>>> - you could use sizeof(mgreg_t) instead of SIZEOF_REGISTER to be
>>>>>>>> consistent with
>>>>>>>>   the usage of sizeof(gpointer).
>>>>>>>>
>>>>>>>
>>>>>>> Sounds good.  I'll try to use sizeof for all compiled code and only
>>>>>>> use SIZEOF_REGISTER/SIZEOF_VOID_P for pre-processor directives only.
>>>>>>>
>>>>>>>
>>>>>>>> Other than these, I think the changes look fine, they aren't that
>>>>>>>> disruptive, since they don't
>>>>>>>> change the non-nacl behavior at all.
>>>>>>>>
>>>>>>>>
>>>>>>> Great!  I was worried just based on LOC changed that it might get
>>>>>>> more resistance.  In truth I'm more worried about future Mono changes
>>>>>>> accidentally breaking NaCl behavior.  I'm planning on getting some automated
>>>>>>> testing implemented soon to combat this though.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> On Tue, Dec 21, 2010 at 9:12 PM, Elijah Taylor <
>>>>>>>> elijahtaylor at google.com> wrote:
>>>>>>>>
>>>>>>>>> Greetings Mono developers!
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> *[tl;dr  very large patch for Native Client<http://www.chromium.org/nativeclient> support
>>>>>>>>> hosted here <https://github.com/elijahtaylor/mono>, would love
>>>>>>>>> feedback and many eyes to look at it]
>>>>>>>>> *
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I'm back with another round of changes for supporting Google's
>>>>>>>>> Native Client (NaCl), including support for amd64, JIT compilation, and
>>>>>>>>> Garbage Collection.  It's a large set of changes, forked on Dec 14 in github
>>>>>>>>> @ https://github.com/elijahtaylor/mono.  I would appreciate
>>>>>>>>> feedback on these changes... to facilitate this, I'll try to explain the
>>>>>>>>> largest changes by feature (please email if clarification is needed):
>>>>>>>>>
>>>>>>>>> *1) amd64 codegen*
>>>>>>>>>
>>>>>>>>>    - Rules located here:
>>>>>>>>>    http://www.chromium.org/nativeclient/design-documents/nacl-sfi-model-on-x86-64-systems
>>>>>>>>>       - Removed %r15 from register allocation, LMF save/restore,
>>>>>>>>>       etc.  (r15 is special and not modifiable by untrusted code)
>>>>>>>>>       - Sandbox all data access through membase address mode.  If
>>>>>>>>>       not %rsp or %rbp relative, re-write as clearing upper 32-bits + memindex
>>>>>>>>>       addressing
>>>>>>>>>       - align functions, call sites
>>>>>>>>>       - Sandbox returns and all indirect jumps (need to be 32-byte
>>>>>>>>>       aligned, cleared upper 32-bits)
>>>>>>>>>       - Never omit frame pointer as general operations to rbp
>>>>>>>>>       aren't allowed
>>>>>>>>>
>>>>>>>>> *2) NaCl x86-64 is ILP32 (this is the largest set of changes and
>>>>>>>>> may make some mono devs unhappy)*
>>>>>>>>>
>>>>>>>>>    - Set SIZEOF_REGISTER == 8 while sizeof(gpointer) == 4 for NaCl
>>>>>>>>>    amd64 (we can use 8-byte instructions, but pointers are 4-bytes)
>>>>>>>>>    - Re-write large portions of mini-amd64.c, tramp-amd64.c,
>>>>>>>>>    exceptions-amd64.c, mini.c, method-to-ir.c to use appropriate sizes
>>>>>>>>>    (SIZEOF_REGISTER, sizeof(gpointer), literal '8').  *These
>>>>>>>>>    changes are disruptive, but ultimately they should be more correct than what
>>>>>>>>>    was there before.  *It's our opinion that these changes
>>>>>>>>>    actually improve Mono despite their impact.
>>>>>>>>>    - We only generate NaCl amd64 code from an ILP32 machine
>>>>>>>>>    (either a 32-bit application for AOT code, or NaCl runtime JIT), so we may
>>>>>>>>>    not have caught all of the [8 <--> SIZEOF_REGISTER] conversions, but we
>>>>>>>>>    likely caught most of the [sizeof(gpointer) <--> SIZEOF_REGISTER] and [8
>>>>>>>>>    <--> sizeof(gpointer)] changes that are necessary.
>>>>>>>>>    - Change atomic operations and default pointer directives to
>>>>>>>>>    use 32-bit instructions (long instead of quad)
>>>>>>>>>    - Change default operations to use 32-bit integers/pointers
>>>>>>>>>    (eg, OP_LOAD_MEMBASE uses 4-bytes instead of 8)
>>>>>>>>>
>>>>>>>>> *3) JIT support for NaCl*
>>>>>>>>>
>>>>>>>>>    - Since we're unable to emit code directly in its final
>>>>>>>>>    executable location, we instead:
>>>>>>>>>       - reserve a buffer on the heap
>>>>>>>>>       - create a hash table entry mapping the temp location and
>>>>>>>>>       final location
>>>>>>>>>       - modify all non-local patches relative to the final
>>>>>>>>>       location
>>>>>>>>>       - request the NaCl runtime to install the created code in
>>>>>>>>>       the final location
>>>>>>>>>    - See mono/utils/mono-codeman.c changes for more detail.
>>>>>>>>>    - For every codeman *reserve*, we must add a codeman *validate*call in order to install the method/trampoline/blob in the final location
>>>>>>>>>    (as well as validate it for NaCl, pad it out, etc)
>>>>>>>>>    - We don't delete or reuse code  (we can, but it's icky and the
>>>>>>>>>    benefits don't outweigh the cost)
>>>>>>>>>    - Backpatching changed to use NaCl syscalls to modify existing
>>>>>>>>>    dynamic code
>>>>>>>>>
>>>>>>>>> *4) GC support for NaCl (boehm only)*
>>>>>>>>>
>>>>>>>>>    - NaCl compiler and Mono code generator both emit
>>>>>>>>>    instrumentation at GC "safe points" (back branches and function prologs),
>>>>>>>>>    for cooperative thread parking (we're not allowed to send and receive
>>>>>>>>>    signals)
>>>>>>>>>    - Added new opcode OP_NACL_GC_SAFE_POINT to handle mono
>>>>>>>>>    instrumentation
>>>>>>>>>    - modified pthread_stop_world.c and pthread_support.c somewhat
>>>>>>>>>    extensively to support this new way of stopping the world
>>>>>>>>>    - wrapped pthread_exit because NaCl doesn't support pthread
>>>>>>>>>    cleanup functions
>>>>>>>>>    - added machine type NACL to libgc with machine specific
>>>>>>>>>    defines
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> *5) Misc bug fixes (not NaCl-specific)*
>>>>>>>>>
>>>>>>>>>    - fix *x86_memindex_emit* when disp is 32-bit
>>>>>>>>>    - properly exclude code in libgc/gc_dlopen.c when
>>>>>>>>>    DYNAMIC_LOADING not defined
>>>>>>>>>    - properly exclude code based on DISABLE_SOCKETS by including
>>>>>>>>>    config.h before checking define
>>>>>>>>>    - clean up calculation of offset for amd64 AOT specific
>>>>>>>>>    trampoline args
>>>>>>>>>    - fix bug in *mono_bblock_insert_before_ins* when trying to
>>>>>>>>>    insert an instruction to the beginning of an existing basic block.
>>>>>>>>>    - fix small typo bug in genmdesc.pl which kept amd64 from being
>>>>>>>>>    able to be a target of cross compiling
>>>>>>>>>    - fix struct passing in amd64 with sizeof(struct) == 16 when
>>>>>>>>>    fields aren't 8-byte aligned (eg, first field is 12 bytes, second field is 4
>>>>>>>>>    bytes), pass on stack instead of in registers (mini-amd64.c:*
>>>>>>>>>    add_valuetype*)
>>>>>>>>>    - add extra checks to mini-amd64.c:*mono_arch_emit_exceptions*to keep exception/R4/R8 emitting from overflowing a buffer silently
>>>>>>>>>    - fix bugs in *new_codechunk* and *
>>>>>>>>>    mono_code_manager_reserve_align* which allowed unaligned code
>>>>>>>>>    to be allocated.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I know we're close to holidays so I don't have any delusions that
>>>>>>>>> these changes will get in by the end of the year :)  Please feel free to
>>>>>>>>> pick apart these changes and let me know if there are things that should be
>>>>>>>>> changed.
>>>>>>>>>
>>>>>>>>> -Elijah
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> Mono-devel-list mailing list
>>>>>>>>> Mono-devel-list at lists.ximian.com
>>>>>>>>> http://lists.ximian.com/mailman/listinfo/mono-devel-list
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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