[M3devel] "C-generating backend progress report, that nobody asked for" :)

[Antony Hosking]

Stock debuggers are designed for C.  They generally will not be able to grok M3.  Better to use M3 run-time type information as per m3gdb.  See 10.1145/143103.143112.


On Sep 9, 2012, at 4:07 PM, Jay <jay.krell at cornell.edu> wrote:

> The current method stinks for stock debugging. As I understand, globals are combined into structs & the fields all have generated names, & global records are flattened therein.
> 
> 
> It works. But stock debuggers see garbage.
> 
> 
>  - Jay (briefly/pocket-sized-computer-aka-phone)
> 
> On Sep 9, 2012, at 12:22 PM, Antony Hosking <hosking at cs.purdue.edu> wrote:
> 
>> I mis-spoke.  I think LLVM can cope with much the same as we currently have.  Front-end will continue to compute alignments and layouts.  We can assert the front-end’s datalayout by passing it to LLVM explicitly, which will complain if it does not match the actual target.  This is a rather nice feature of LLVM in that it allows us to retain control while having LLVM optimize accordingly.
>> 
>> On Sep 9, 2012, at 11:05 AM, Antony Hosking <hosking at cs.purdue.edu> wrote:
>> 
>>> Yes, agreed, these need to be properly typed too.
>>> First step will be to lift the M3CG interface.
>>> Problem: The compiler needs to control layout so that the run-time system knows where to find things.  This means that we need to assert alignments and layouts produced by the backend are the same as those in the front-end.  LLVM has nice ways to do this.  How will we do it in the C backend?  Does C have sufficient control over alignment?
>>> 
>>> On Sep 9, 2012, at 10:53 AM, Jay <jay.krell at cornell.edu> wrote:
>>> 
>>>> Btw, can this include "segment"/globals? Can they each be separate named variables? At least some of them?
>>>> 
>>>> 
>>>>  - Jay (briefly/pocket-sized-computer-aka-phone)
>>>> 
>>>> On Sep 9, 2012, at 7:48 AM, Antony Hosking <hosking at cs.purdue.edu> wrote:
>>>> 
>>>>> I’m looking at it...
>>>>> 
>>>>> First step is to lift slightly the level of M3CG to use properly typed memory access, instead of untyped address + offset.
>>>>> 
>>>>> On Sep 9, 2012, at 2:32 AM, Dragiša Durić <dragisha at m3w.org> wrote:
>>>>> 
>>>>>> I hope somebody will take on LLVM :).
>>>>>> 
>>>>> 
>>> 
>> 

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