bitcode / bytecode

Hi list,

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.

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.

Hi Ariel,

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.

Anyone,

can you say what was the reason to rename bytecode? I am still interesting in

2010/9/29 Duncan Sands <baldrick@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.

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. :slight_smile:

-bw

The format is literally a bitstream, not a bytestream. See this document for more details:
http://llvm.org/docs/BitCodeFormat.html

-Chris

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

We don't do anything tricky, feel free to look at the source in llvm/lib/Bitcode.

-Chris