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b3f1379509
Encode hashes as bytes, not varint In a few places, we store hashes as `u64` or `u128` and then apply `derive(Decodable, Encodable)` to the enclosing struct/enum. It is more efficient to encode hashes directly than try to apply some varint encoding. This PR adds two new types `Hash64` and `Hash128` which are produced by `StableHasher` and replace every use of storing a `u64` or `u128` that represents a hash. Distribution of the byte lengths of leb128 encodings, from `x build --stage 2` with `incremental = true` Before: ``` ( 1) 373418203 (53.7%, 53.7%): 1 ( 2) 196240113 (28.2%, 81.9%): 3 ( 3) 108157958 (15.6%, 97.5%): 2 ( 4) 17213120 ( 2.5%, 99.9%): 4 ( 5) 223614 ( 0.0%,100.0%): 9 ( 6) 216262 ( 0.0%,100.0%): 10 ( 7) 15447 ( 0.0%,100.0%): 5 ( 8) 3633 ( 0.0%,100.0%): 19 ( 9) 3030 ( 0.0%,100.0%): 8 ( 10) 1167 ( 0.0%,100.0%): 18 ( 11) 1032 ( 0.0%,100.0%): 7 ( 12) 1003 ( 0.0%,100.0%): 6 ( 13) 10 ( 0.0%,100.0%): 16 ( 14) 10 ( 0.0%,100.0%): 17 ( 15) 5 ( 0.0%,100.0%): 12 ( 16) 4 ( 0.0%,100.0%): 14 ``` After: ``` ( 1) 372939136 (53.7%, 53.7%): 1 ( 2) 196240140 (28.3%, 82.0%): 3 ( 3) 108014969 (15.6%, 97.5%): 2 ( 4) 17192375 ( 2.5%,100.0%): 4 ( 5) 435 ( 0.0%,100.0%): 5 ( 6) 83 ( 0.0%,100.0%): 18 ( 7) 79 ( 0.0%,100.0%): 10 ( 8) 50 ( 0.0%,100.0%): 9 ( 9) 6 ( 0.0%,100.0%): 19 ``` The remaining 9 or 10 and 18 or 19 are `u64` and `u128` respectively that have the high bits set. As far as I can tell these are coming primarily from `SwitchTargets`. |
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| .. | ||
| back | ||
| coverageinfo | ||
| debuginfo | ||
| llvm | ||
| abi.rs | ||
| allocator.rs | ||
| asm.rs | ||
| attributes.rs | ||
| base.rs | ||
| builder.rs | ||
| callee.rs | ||
| common.rs | ||
| consts.rs | ||
| context.rs | ||
| declare.rs | ||
| errors.rs | ||
| intrinsic.rs | ||
| lib.rs | ||
| llvm_util.rs | ||
| mono_item.rs | ||
| type_.rs | ||
| type_of.rs | ||
| va_arg.rs | ||
| value.rs | ||