[Mono-dev] [PATCH] more support for Google Native Client
Elijah Taylor
elijahtaylor at google.com
Thu Jan 6 14:41:45 EST 2011
Page alignment would be good enough, but I wasn't clear because I had
forgotten some details. When I saw this behavior we were using the "dummy"
implementation of mono_valloc which falls back on malloc, which I don't
believe we use anymore for the AOT compiler since it's a native app.
This code is probably not necessary for NaCl anymore, but if anyone is using
this dummy implementation then it's still a valid fix.
On Thu, Jan 6, 2011 at 11:31 AM, Zoltan Varga <vargaz at gmail.com> wrote:
> Hi,
>
> Its fixed now, it was missing a (uintptr_t) cast around align_mask.
> mono_valloc () is supposed to return pagesize aligned memory, isn't that
> enough ?
>
> Zoltan
>
> On Thu, Jan 6, 2011 at 8:14 PM, Elijah Taylor <elijahtaylor at google.com>wrote:
>
>> This bit of code runs for our AOT compiler, but not for our JIT (in that
>> case, it's a native 32-bit app that defines __native_client_codegen__).
>>
>> The problem is that chunk->data isn't guaranteed to be aligned to
>> MIN_ALIGN **or** the alignment you pass into *
>> mono_code_manager_reserve_align* if you use mono_valloc instead of
>> dlmemalign in *new_codechunk*. But chunk->pos is aligned to the
>> alignment passed in, so the returned pointer could be misaligned.
>>
>> As you can see in the alloc function I adjusted it to give MIN_ALIGN - 1
>> extra bytes to account for this slop, and there's an identical piece to this
>> below for new codechunks that are allocated. I'm curious why this is
>> causing problems for non-nacl builds... if chunk->data is aligned this
>> should essentially be a no-op, and if it's not aligned, this code is
>> supposed to fix that. Is there a simple test I can run to see the failure?
>>
>>
>> On Thu, Jan 6, 2011 at 3:43 AM, Zoltan Varga <vargaz at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> I had to revert this change, as it was causing crashes on amd64:
>>> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>>> @@ -357,8 +494,10 @@ mono_code_manager_reserve_align (MonoCodeManager
>>> *cman, int size, int alignment)
>>> for (chunk = cman->current; chunk; chunk = chunk->next) {
>>> if (ALIGN_INT (chunk->pos, alignment) + size <= chunk->size) {
>>> chunk->pos = ALIGN_INT (chunk->pos, alignment);
>>> - ptr = chunk->data + chunk->pos;
>>> - chunk->pos += size;
>>> + /* Align the chunk->data we add to chunk->pos */
>>> + /* or we can't guarantee proper alignment */
>>> + ptr = (void*)((((uintptr_t)chunk->data + align_mask) & ~align_mask) +
>>> chunk->pos);
>>> + chunk->pos = ((char*)ptr - chunk->data) + size;
>>> return ptr;
>>> }
>>> }
>>> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>
>>> it was inside a #ifndef native_client, so why is this needed ?
>>>
>>> Zoltan
>>>
>>> On Thu, Jan 6, 2011 at 11:34 AM, Zoltan Varga <vargaz at gmail.com> wrote:
>>>
>>>> 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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