https://github.com/angerman/data-bitcode

Data.BitCode
https://github.com/angerman/data-bitcode

Last synced: 14 days ago
JSON representation

Data.BitCode

• Host: GitHub
• URL: https://github.com/angerman/data-bitcode
• Owner: angerman
• License: bsd-3-clause
• Created: 2016-08-06T00:27:13.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2017-11-10T06:46:46.000Z (about 7 years ago)
• Last Synced: 2024-11-14T02:03:59.829Z (about 2 months ago)
• Language: HTML
• Size: 1.32 MB
• Stars: 4
• Watchers: 5
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
# Data.Bitstream

*This is an alternative implementation to the `[Bool]` heavy solution in

[Data.BitCode](https://github.com/angerman/data-bitcode).*

`Data.Bitstream` is a LLVM bitcode serializer. The module takes bitcode

records and turns them into the bitcode bitstream, which is then written

to disk as bytes.

## Bitcode

LLVM Bitcode is a series of bits emitted into a stream. This does not 

need to align with bytes. Notably bytes on disk usually store their least

significant bit last, while it would come first in bitcode. Example:

| byte           | `de`       | `c0`      | `17`       | `0b`       |

| bits on disk   | `11011110` | `1100000` | `00010111` | `00001011` |

| bits in stream | `01111011` | `0000011` | `11101000` | `00001011` |

However flipping the bytes in the `ByteString` prior to writing to disk

seems rather cheap (~16M/s) (see `bench.html`).

## Building 

With [Data.BitCode](https://github.com/angerman/data-bitcode) and

[Data.BitCode.LLVM](https://gihtub.com/angerman/data-bitcode-llvm), checked

out in the same directory as

[Data.Bistream](https://github.com/angerman/data-bitstream), this module should

be buildable with `cabal new-build` (see also the `cabal.project` file).

## Testing

`cabal new-test` should run a series of tests, trying to produce bitcode and

ensure some basic validity of the `Bitstream`.

## Benchmarking

`cabal new-bench` should try to do some rather expensive, yet common bit

concatinations on `Bitstream` and the underlying `Stream` data types. The

benchmark has two parts. One is a synthetic which tries some simple 

concatination. And the other one is a real world benchmark which attempts

to build the object file for `main = putStrLn 'Hello World'` by taking the

serialized bitcode records for said program and runs them through the

serializer.

## Profiling

The module also contains the `test` executable. Which takes a serialized

bitcode record file as input and runs the `Bitstream` serializer over it.

`cabal new-build --enable-profiling` should produce the profiled binary.

```

$(find dist-newstyle -name "test" -type f) bench/data/Main.bcbin +RTS -P

```

should produce the `test.prof` profile.

*I like [viewprof](https://hackage.haskell.org/package/viewprof) a lot for

viewing haskell profiles*