[LLVMdev] bitcode / bytecode
Ariel Feinerman
As long as I know English the word "bit" is a "small pice", . Why in set of documentation ir is "bytecode", in other set or llvm source is "bitecode"?
What is the right? Different people call the same thing such differently.
--
best regards
Ariel
Duncan Sands
> As long as I know English the word "bit" is a "small pice", . Why in set of
> documentation ir is "bytecode", in other set or llvm source is "bitecode"?
> What is the right? Different people call the same thing such differently.
it used to be called bytecode, now it is called bitcode, but not all
documents were updated it seems.
Ciao,
Duncan.
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Duncan Sands
> can you say what was the reason to rename bytecode? I am still interesting in
you forgot to send this to the mailing list, so I have (probably someone there
knows better than I). I think the reason is that bitcode is bit-packed, i.e.
you can have multiple pieces of information stored in one byte, so byte code
was a misnomer.
Ciao,
Duncan.
>
> 2010/9/29 Duncan Sands <bald...@free.fr <mailto:bald...@free.fr>>
>
> Hi Ariel,
>
> > As long as I know English the word "bit" is a "small pice", . Why in set of
> > documentation ir is "bytecode", in other set or llvm source is "bitecode"?
> > What is the right? Different people call the same thing such differently.
>
> it used to be called bytecode, now it is called bitcode, but not all
> documents were updated it seems.
>
> Ciao,
>
> Duncan.
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>
>
>
> --
> best regards
> Ariel
Ariel Feinerman
can you say what was the reason to rename bytecode? I am still interesting in
best regards
Ariel
Bill Wendling
-bw
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Chris Lattner
On Sep 29, 2010, at 3:12 PM, Bill Wendling wrote:
> Chris rewrote the original LLVM bytecode into it's present bitcode form. The newer code is much smaller than the previous form. That would be my guess for why he chose to call it bitcode. Of course, he can say for himself. :-)
The format is literally a bitstream, not a bytestream. See this document for more details:
http://llvm.org/docs/BitCodeFormat.html
-Chris
Joachim Durchholz
>
> The format is literally a bitstream, not a bytestream. See this document for more details:
> http://llvm.org/docs/BitCodeFormat.html
Ah... something I always meant to ask: How does the LLVM infrastructure
deal with the added overhead of packing/unpacking a bitstream?
Ignore it since modern CPUs can deal with that?
Some ingenious algorithm?
Last time I heard about a bitstream format was with the i432, where
hindsight lore has it that bitstreams are just too complicated to
maintain, but I guess some things might have changed since then.
Regards,
Jo
Chris Lattner
On Sep 30, 2010, at 5:26 AM, Joachim Durchholz wrote:
> Am 30.09.2010 00:34, schrieb Chris Lattner:
>>
>> The format is literally a bitstream, not a bytestream. See this document for more details:
>> http://llvm.org/docs/BitCodeFormat.html
>
> Ah... something I always meant to ask: How does the LLVM infrastructure
> deal with the added overhead of packing/unpacking a bitstream?
> Ignore it since modern CPUs can deal with that?
> Some ingenious algorithm?
We don't do anything tricky, feel free to look at the source in llvm/lib/Bitcode.
-Chris