[llvm-branch-commits] [llvm] [Support] Integrate SipHash.cpp into libSupport. (PR #94394)
Ahmed Bougacha via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Wed Jun 5 11:01:37 PDT 2024
https://github.com/ahmedbougacha updated https://github.com/llvm/llvm-project/pull/94394
>From 1e9a3fde97d907c3cd6be33db91d1c18c7236ffb Mon Sep 17 00:00:00 2001
From: Ahmed Bougacha <ahmed at bougacha.org>
Date: Tue, 4 Jun 2024 12:41:47 -0700
Subject: [PATCH 1/4] [Support] Reformat SipHash.cpp to match libSupport.
While there, give it our usual file header and an acknowledgement,
and remove the imported README.md.SipHash.
---
llvm/lib/Support/README.md.SipHash | 126 --------------
llvm/lib/Support/SipHash.cpp | 264 ++++++++++++++---------------
2 files changed, 129 insertions(+), 261 deletions(-)
delete mode 100644 llvm/lib/Support/README.md.SipHash
diff --git a/llvm/lib/Support/README.md.SipHash b/llvm/lib/Support/README.md.SipHash
deleted file mode 100644
index 4de3cd1854681..0000000000000
--- a/llvm/lib/Support/README.md.SipHash
+++ /dev/null
@@ -1,126 +0,0 @@
-# SipHash
-
-[](http://creativecommons.org/publicdomain/zero/1.0/)
-
-[](https://opensource.org/licenses/MIT)
-
-
-SipHash is a family of pseudorandom functions (PRFs) optimized for speed on short messages.
-This is the reference C code of SipHash: portable, simple, optimized for clarity and debugging.
-
-SipHash was designed in 2012 by [Jean-Philippe Aumasson](https://aumasson.jp)
-and [Daniel J. Bernstein](https://cr.yp.to) as a defense against [hash-flooding
-DoS attacks](https://aumasson.jp/siphash/siphashdos_29c3_slides.pdf).
-
-SipHash is:
-
-* *Simpler and faster* on short messages than previous cryptographic
-algorithms, such as MACs based on universal hashing.
-
-* *Competitive in performance* with insecure non-cryptographic algorithms, such as [fhhash](https://github.com/cbreeden/fxhash).
-
-* *Cryptographically secure*, with no sign of weakness despite multiple [cryptanalysis](https://eprint.iacr.org/2019/865) [projects](https://eprint.iacr.org/2019/865) by leading cryptographers.
-
-* *Battle-tested*, with successful integration in OSs (Linux kernel, OpenBSD,
-FreeBSD, FreeRTOS), languages (Perl, Python, Ruby, etc.), libraries (OpenSSL libcrypto,
-Sodium, etc.) and applications (Wireguard, Redis, etc.).
-
-As a secure pseudorandom function (a.k.a. keyed hash function), SipHash can also be used as a secure message authentication code (MAC).
-But SipHash is *not a hash* in the sense of general-purpose key-less hash function such as BLAKE3 or SHA-3.
-SipHash should therefore always be used with a secret key in order to be secure.
-
-
-## Variants
-
-The default SipHash is *SipHash-2-4*: it takes a 128-bit key, does 2 compression
-rounds, 4 finalization rounds, and returns a 64-bit tag.
-
-Variants can use a different number of rounds. For example, we proposed *SipHash-4-8* as a conservative version.
-
-The following versions are not described in the paper but were designed and analyzed to fulfill applications' needs:
-
-* *SipHash-128* returns a 128-bit tag instead of 64-bit. Versions with specified number of rounds are SipHash-2-4-128, SipHash4-8-128, and so on.
-
-* *HalfSipHash* works with 32-bit words instead of 64-bit, takes a 64-bit key,
-and returns 32-bit or 64-bit tags. For example, HalfSipHash-2-4-32 has 2
-compression rounds, 4 finalization rounds, and returns a 32-bit tag.
-
-
-## Security
-
-(Half)SipHash-*c*-*d* with *c* ≥ 2 and *d* ≥ 4 is expected to provide the maximum PRF
-security for any function with the same key and output size.
-
-The standard PRF security goal allow the attacker access to the output of SipHash on messages chosen adaptively by the attacker.
-
-Security is limited by the key size (128 bits for SipHash), such that
-attackers searching 2<sup>*s*</sup> keys have chance 2<sup>*s*−128</sup> of finding
-the SipHash key.
-Security is also limited by the output size. In particular, when
-SipHash is used as a MAC, an attacker who blindly tries 2<sup>*s*</sup> tags will
-succeed with probability 2<sup>*s*-*t*</sup>, if *t* is that tag's bit size.
-
-
-## Research
-
-* [Research paper](https://www.aumasson.jp/siphash/siphash.pdf) "SipHash: a fast short-input PRF" (accepted at INDOCRYPT 2012)
-* [Slides](https://cr.yp.to/talks/2012.12.12/slides.pdf) of the presentation of SipHash at INDOCRYPT 2012 (Bernstein)
-* [Slides](https://www.aumasson.jp/siphash/siphash_slides.pdf) of the presentation of SipHash at the DIAC workshop (Aumasson)
-
-
-## Usage
-
-Running
-
-```sh
- make
-```
-
-will build tests for
-
-* SipHash-2-4-64
-* SipHash-2-4-128
-* HalfSipHash-2-4-32
-* HalfSipHash-2-4-64
-
-
-```C
- ./test
-```
-
-verifies 64 test vectors, and
-
-```C
- ./debug
-```
-
-does the same and prints intermediate values.
-
-The code can be adapted to implement SipHash-*c*-*d*, the version of SipHash
-with *c* compression rounds and *d* finalization rounds, by defining `cROUNDS`
-or `dROUNDS` when compiling. This can be done with `-D` command line arguments
-to many compilers such as below.
-
-```sh
-gcc -Wall --std=c99 -DcROUNDS=2 -DdROUNDS=4 siphash.c halfsiphash.c test.c -o test
-```
-
-The `makefile` also takes *c* and *d* rounds values as parameters.
-
-```sh
-make cROUNDS=2 dROUNDS=4
-```
-
-Obviously, if the number of rounds is modified then the test vectors
-won't verify.
-
-## Intellectual property
-
-This code is copyright (c) 2014-2023 Jean-Philippe Aumasson, Daniel J.
-Bernstein. It is multi-licensed under
-
-* [CC0](./LICENCE_CC0)
-* [MIT](./LICENSE_MIT).
-* [Apache 2.0 with LLVM exceptions](./LICENSE_A2LLVM).
-
diff --git a/llvm/lib/Support/SipHash.cpp b/llvm/lib/Support/SipHash.cpp
index c6d16e205521d..f31023740011f 100644
--- a/llvm/lib/Support/SipHash.cpp
+++ b/llvm/lib/Support/SipHash.cpp
@@ -1,25 +1,19 @@
-/*
- SipHash reference C implementation
-
- Copyright (c) 2012-2022 Jean-Philippe Aumasson
- <jeanphilippe.aumasson at gmail.com>
- Copyright (c) 2012-2014 Daniel J. Bernstein <djb at cr.yp.to>
-
- To the extent possible under law, the author(s) have dedicated all copyright
- and related and neighboring rights to this software to the public domain
- worldwide. This software is distributed without any warranty.
-
- You should have received a copy of the CC0 Public Domain Dedication along
- with
- this software. If not, see
- <http://creativecommons.org/publicdomain/zero/1.0/>.
- */
+//===--- SipHash.cpp - An ABI-stable string hash --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
#include "siphash.h"
#include <assert.h>
#include <stddef.h>
#include <stdint.h>
+// Lightly adapted from the SipHash reference C implementation by
+// Jean-Philippe Aumasson and Daniel J. Bernstein.
+
/* default: SipHash-2-4 */
#ifndef cROUNDS
#define cROUNDS 2
@@ -31,49 +25,49 @@
#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
#define U32TO8_LE(p, v) \
- (p)[0] = (uint8_t)((v)); \
- (p)[1] = (uint8_t)((v) >> 8); \
- (p)[2] = (uint8_t)((v) >> 16); \
- (p)[3] = (uint8_t)((v) >> 24);
+ (p)[0] = (uint8_t)((v)); \
+ (p)[1] = (uint8_t)((v) >> 8); \
+ (p)[2] = (uint8_t)((v) >> 16); \
+ (p)[3] = (uint8_t)((v) >> 24);
#define U64TO8_LE(p, v) \
- U32TO8_LE((p), (uint32_t)((v))); \
- U32TO8_LE((p) + 4, (uint32_t)((v) >> 32));
+ U32TO8_LE((p), (uint32_t)((v))); \
+ U32TO8_LE((p) + 4, (uint32_t)((v) >> 32));
#define U8TO64_LE(p) \
- (((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) | \
- ((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) | \
- ((uint64_t)((p)[4]) << 32) | ((uint64_t)((p)[5]) << 40) | \
- ((uint64_t)((p)[6]) << 48) | ((uint64_t)((p)[7]) << 56))
+ (((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) | \
+ ((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) | \
+ ((uint64_t)((p)[4]) << 32) | ((uint64_t)((p)[5]) << 40) | \
+ ((uint64_t)((p)[6]) << 48) | ((uint64_t)((p)[7]) << 56))
#define SIPROUND \
- do { \
- v0 += v1; \
- v1 = ROTL(v1, 13); \
- v1 ^= v0; \
- v0 = ROTL(v0, 32); \
- v2 += v3; \
- v3 = ROTL(v3, 16); \
- v3 ^= v2; \
- v0 += v3; \
- v3 = ROTL(v3, 21); \
- v3 ^= v0; \
- v2 += v1; \
- v1 = ROTL(v1, 17); \
- v1 ^= v2; \
- v2 = ROTL(v2, 32); \
- } while (0)
+ do { \
+ v0 += v1; \
+ v1 = ROTL(v1, 13); \
+ v1 ^= v0; \
+ v0 = ROTL(v0, 32); \
+ v2 += v3; \
+ v3 = ROTL(v3, 16); \
+ v3 ^= v2; \
+ v0 += v3; \
+ v3 = ROTL(v3, 21); \
+ v3 ^= v0; \
+ v2 += v1; \
+ v1 = ROTL(v1, 17); \
+ v1 ^= v2; \
+ v2 = ROTL(v2, 32); \
+ } while (0)
#ifdef DEBUG_SIPHASH
#include <stdio.h>
#define TRACE \
- do { \
- printf("(%3zu) v0 %016" PRIx64 "\n", inlen, v0); \
- printf("(%3zu) v1 %016" PRIx64 "\n", inlen, v1); \
- printf("(%3zu) v2 %016" PRIx64 "\n", inlen, v2); \
- printf("(%3zu) v3 %016" PRIx64 "\n", inlen, v3); \
- } while (0)
+ do { \
+ printf("(%3zu) v0 %016" PRIx64 "\n", inlen, v0); \
+ printf("(%3zu) v1 %016" PRIx64 "\n", inlen, v1); \
+ printf("(%3zu) v2 %016" PRIx64 "\n", inlen, v2); \
+ printf("(%3zu) v3 %016" PRIx64 "\n", inlen, v3); \
+ } while (0)
#else
#define TRACE
#endif
@@ -82,104 +76,104 @@
Computes a SipHash value
*in: pointer to input data (read-only)
inlen: input data length in bytes (any size_t value)
- *k: pointer to the key data (read-only), must be 16 bytes
+ *k: pointer to the key data (read-only), must be 16 bytes
*out: pointer to output data (write-only), outlen bytes must be allocated
outlen: length of the output in bytes, must be 8 or 16
*/
int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
const size_t outlen) {
- const unsigned char *ni = (const unsigned char *)in;
- const unsigned char *kk = (const unsigned char *)k;
-
- assert((outlen == 8) || (outlen == 16));
- uint64_t v0 = UINT64_C(0x736f6d6570736575);
- uint64_t v1 = UINT64_C(0x646f72616e646f6d);
- uint64_t v2 = UINT64_C(0x6c7967656e657261);
- uint64_t v3 = UINT64_C(0x7465646279746573);
- uint64_t k0 = U8TO64_LE(kk);
- uint64_t k1 = U8TO64_LE(kk + 8);
- uint64_t m;
- int i;
- const unsigned char *end = ni + inlen - (inlen % sizeof(uint64_t));
- const int left = inlen & 7;
- uint64_t b = ((uint64_t)inlen) << 56;
- v3 ^= k1;
- v2 ^= k0;
- v1 ^= k1;
- v0 ^= k0;
-
- if (outlen == 16)
- v1 ^= 0xee;
-
- for (; ni != end; ni += 8) {
- m = U8TO64_LE(ni);
- v3 ^= m;
-
- TRACE;
- for (i = 0; i < cROUNDS; ++i)
- SIPROUND;
-
- v0 ^= m;
- }
-
- switch (left) {
- case 7:
- b |= ((uint64_t)ni[6]) << 48;
- /* FALLTHRU */
- case 6:
- b |= ((uint64_t)ni[5]) << 40;
- /* FALLTHRU */
- case 5:
- b |= ((uint64_t)ni[4]) << 32;
- /* FALLTHRU */
- case 4:
- b |= ((uint64_t)ni[3]) << 24;
- /* FALLTHRU */
- case 3:
- b |= ((uint64_t)ni[2]) << 16;
- /* FALLTHRU */
- case 2:
- b |= ((uint64_t)ni[1]) << 8;
- /* FALLTHRU */
- case 1:
- b |= ((uint64_t)ni[0]);
- break;
- case 0:
- break;
- }
-
- v3 ^= b;
+ const unsigned char *ni = (const unsigned char *)in;
+ const unsigned char *kk = (const unsigned char *)k;
+
+ assert((outlen == 8) || (outlen == 16));
+ uint64_t v0 = UINT64_C(0x736f6d6570736575);
+ uint64_t v1 = UINT64_C(0x646f72616e646f6d);
+ uint64_t v2 = UINT64_C(0x6c7967656e657261);
+ uint64_t v3 = UINT64_C(0x7465646279746573);
+ uint64_t k0 = U8TO64_LE(kk);
+ uint64_t k1 = U8TO64_LE(kk + 8);
+ uint64_t m;
+ int i;
+ const unsigned char *end = ni + inlen - (inlen % sizeof(uint64_t));
+ const int left = inlen & 7;
+ uint64_t b = ((uint64_t)inlen) << 56;
+ v3 ^= k1;
+ v2 ^= k0;
+ v1 ^= k1;
+ v0 ^= k0;
+
+ if (outlen == 16)
+ v1 ^= 0xee;
+
+ for (; ni != end; ni += 8) {
+ m = U8TO64_LE(ni);
+ v3 ^= m;
TRACE;
for (i = 0; i < cROUNDS; ++i)
- SIPROUND;
-
- v0 ^= b;
-
- if (outlen == 16)
- v2 ^= 0xee;
- else
- v2 ^= 0xff;
-
- TRACE;
- for (i = 0; i < dROUNDS; ++i)
- SIPROUND;
-
- b = v0 ^ v1 ^ v2 ^ v3;
- U64TO8_LE(out, b);
-
- if (outlen == 8)
- return 0;
+ SIPROUND;
+
+ v0 ^= m;
+ }
+
+ switch (left) {
+ case 7:
+ b |= ((uint64_t)ni[6]) << 48;
+ /* FALLTHRU */
+ case 6:
+ b |= ((uint64_t)ni[5]) << 40;
+ /* FALLTHRU */
+ case 5:
+ b |= ((uint64_t)ni[4]) << 32;
+ /* FALLTHRU */
+ case 4:
+ b |= ((uint64_t)ni[3]) << 24;
+ /* FALLTHRU */
+ case 3:
+ b |= ((uint64_t)ni[2]) << 16;
+ /* FALLTHRU */
+ case 2:
+ b |= ((uint64_t)ni[1]) << 8;
+ /* FALLTHRU */
+ case 1:
+ b |= ((uint64_t)ni[0]);
+ break;
+ case 0:
+ break;
+ }
+
+ v3 ^= b;
+
+ TRACE;
+ for (i = 0; i < cROUNDS; ++i)
+ SIPROUND;
+
+ v0 ^= b;
+
+ if (outlen == 16)
+ v2 ^= 0xee;
+ else
+ v2 ^= 0xff;
+
+ TRACE;
+ for (i = 0; i < dROUNDS; ++i)
+ SIPROUND;
+
+ b = v0 ^ v1 ^ v2 ^ v3;
+ U64TO8_LE(out, b);
+
+ if (outlen == 8)
+ return 0;
- v1 ^= 0xdd;
+ v1 ^= 0xdd;
- TRACE;
- for (i = 0; i < dROUNDS; ++i)
- SIPROUND;
+ TRACE;
+ for (i = 0; i < dROUNDS; ++i)
+ SIPROUND;
- b = v0 ^ v1 ^ v2 ^ v3;
- U64TO8_LE(out + 8, b);
+ b = v0 ^ v1 ^ v2 ^ v3;
+ U64TO8_LE(out + 8, b);
- return 0;
+ return 0;
}
>From 3d4f7dcaf8e9c4ad666f84b4ba7c8c742c336896 Mon Sep 17 00:00:00 2001
From: Ahmed Bougacha <ahmed at bougacha.org>
Date: Tue, 4 Jun 2024 12:45:37 -0700
Subject: [PATCH 2/4] [Support] Remove SipHash tracing support.
---
llvm/lib/Support/SipHash.cpp | 18 ------------------
1 file changed, 18 deletions(-)
diff --git a/llvm/lib/Support/SipHash.cpp b/llvm/lib/Support/SipHash.cpp
index f31023740011f..b7cc692b7d6b4 100644
--- a/llvm/lib/Support/SipHash.cpp
+++ b/llvm/lib/Support/SipHash.cpp
@@ -58,20 +58,6 @@
v2 = ROTL(v2, 32); \
} while (0)
-#ifdef DEBUG_SIPHASH
-#include <stdio.h>
-
-#define TRACE \
- do { \
- printf("(%3zu) v0 %016" PRIx64 "\n", inlen, v0); \
- printf("(%3zu) v1 %016" PRIx64 "\n", inlen, v1); \
- printf("(%3zu) v2 %016" PRIx64 "\n", inlen, v2); \
- printf("(%3zu) v3 %016" PRIx64 "\n", inlen, v3); \
- } while (0)
-#else
-#define TRACE
-#endif
-
/*
Computes a SipHash value
*in: pointer to input data (read-only)
@@ -110,7 +96,6 @@ int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
m = U8TO64_LE(ni);
v3 ^= m;
- TRACE;
for (i = 0; i < cROUNDS; ++i)
SIPROUND;
@@ -145,7 +130,6 @@ int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
v3 ^= b;
- TRACE;
for (i = 0; i < cROUNDS; ++i)
SIPROUND;
@@ -156,7 +140,6 @@ int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
else
v2 ^= 0xff;
- TRACE;
for (i = 0; i < dROUNDS; ++i)
SIPROUND;
@@ -168,7 +151,6 @@ int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
v1 ^= 0xdd;
- TRACE;
for (i = 0; i < dROUNDS; ++i)
SIPROUND;
>From 6679d54b2d1b037c849aea3cf04507e5390adc49 Mon Sep 17 00:00:00 2001
From: Ahmed Bougacha <ahmed at bougacha.org>
Date: Tue, 4 Jun 2024 12:48:11 -0700
Subject: [PATCH 3/4] [Support] Integrate SipHash.cpp into libSupport.
Start building it as part of the library, with some minor
tweaks compared to the reference implementation:
- templatize cROUNDS/dROUNDS, as well as 8B/16B result type
- replace assert with static_assert
- return the result directly, as uint64_t/uint128_t
- remove big-endian support
- use LLVM_FALLTHROUGH
The siphash function itself isn't used yet, and will be in a follow-up
commit.
---
llvm/lib/Support/CMakeLists.txt | 4 +-
llvm/lib/Support/SipHash.cpp | 66 ++++++++++-----------------------
2 files changed, 21 insertions(+), 49 deletions(-)
diff --git a/llvm/lib/Support/CMakeLists.txt b/llvm/lib/Support/CMakeLists.txt
index 7cc01a5399911..f5f8447d48d01 100644
--- a/llvm/lib/Support/CMakeLists.txt
+++ b/llvm/lib/Support/CMakeLists.txt
@@ -127,9 +127,6 @@ endif()
add_subdirectory(BLAKE3)
-# Temporarily ignore SipHash.cpp before we fully integrate it into LLVMSupport.
-set(LLVM_OPTIONAL_SOURCES SipHash.cpp)
-
add_llvm_component_library(LLVMSupport
ABIBreak.cpp
AMDGPUMetadata.cpp
@@ -226,6 +223,7 @@ add_llvm_component_library(LLVMSupport
SHA1.cpp
SHA256.cpp
Signposts.cpp
+ SipHash.cpp
SmallPtrSet.cpp
SmallVector.cpp
SourceMgr.cpp
diff --git a/llvm/lib/Support/SipHash.cpp b/llvm/lib/Support/SipHash.cpp
index b7cc692b7d6b4..ef882ae4d8745 100644
--- a/llvm/lib/Support/SipHash.cpp
+++ b/llvm/lib/Support/SipHash.cpp
@@ -6,34 +6,14 @@
//
//===----------------------------------------------------------------------===//
-#include "siphash.h"
-#include <assert.h>
-#include <stddef.h>
-#include <stdint.h>
+#include "llvm/Support/Compiler.h"
+#include <cstdint>
// Lightly adapted from the SipHash reference C implementation by
// Jean-Philippe Aumasson and Daniel J. Bernstein.
-/* default: SipHash-2-4 */
-#ifndef cROUNDS
-#define cROUNDS 2
-#endif
-#ifndef dROUNDS
-#define dROUNDS 4
-#endif
-
#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
-#define U32TO8_LE(p, v) \
- (p)[0] = (uint8_t)((v)); \
- (p)[1] = (uint8_t)((v) >> 8); \
- (p)[2] = (uint8_t)((v) >> 16); \
- (p)[3] = (uint8_t)((v) >> 24);
-
-#define U64TO8_LE(p, v) \
- U32TO8_LE((p), (uint32_t)((v))); \
- U32TO8_LE((p) + 4, (uint32_t)((v) >> 32));
-
#define U8TO64_LE(p) \
(((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) | \
((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) | \
@@ -58,21 +38,15 @@
v2 = ROTL(v2, 32); \
} while (0)
-/*
- Computes a SipHash value
- *in: pointer to input data (read-only)
- inlen: input data length in bytes (any size_t value)
- *k: pointer to the key data (read-only), must be 16 bytes
- *out: pointer to output data (write-only), outlen bytes must be allocated
- outlen: length of the output in bytes, must be 8 or 16
-*/
-int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
- const size_t outlen) {
+template <int cROUNDS, int dROUNDS, class ResultTy>
+static inline ResultTy siphash(const unsigned char *in, uint64_t inlen,
+ const unsigned char (&k)[16]) {
const unsigned char *ni = (const unsigned char *)in;
const unsigned char *kk = (const unsigned char *)k;
- assert((outlen == 8) || (outlen == 16));
+ static_assert(sizeof(ResultTy) == 8 || sizeof(ResultTy) == 16,
+ "result type should be uint64_t or uint128_t");
uint64_t v0 = UINT64_C(0x736f6d6570736575);
uint64_t v1 = UINT64_C(0x646f72616e646f6d);
uint64_t v2 = UINT64_C(0x6c7967656e657261);
@@ -89,7 +63,7 @@ int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
v1 ^= k1;
v0 ^= k0;
- if (outlen == 16)
+ if (sizeof(ResultTy) == 16)
v1 ^= 0xee;
for (; ni != end; ni += 8) {
@@ -105,22 +79,22 @@ int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
switch (left) {
case 7:
b |= ((uint64_t)ni[6]) << 48;
- /* FALLTHRU */
+ LLVM_FALLTHROUGH;
case 6:
b |= ((uint64_t)ni[5]) << 40;
- /* FALLTHRU */
+ LLVM_FALLTHROUGH;
case 5:
b |= ((uint64_t)ni[4]) << 32;
- /* FALLTHRU */
+ LLVM_FALLTHROUGH;
case 4:
b |= ((uint64_t)ni[3]) << 24;
- /* FALLTHRU */
+ LLVM_FALLTHROUGH;
case 3:
b |= ((uint64_t)ni[2]) << 16;
- /* FALLTHRU */
+ LLVM_FALLTHROUGH;
case 2:
b |= ((uint64_t)ni[1]) << 8;
- /* FALLTHRU */
+ LLVM_FALLTHROUGH;
case 1:
b |= ((uint64_t)ni[0]);
break;
@@ -135,7 +109,7 @@ int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
v0 ^= b;
- if (outlen == 16)
+ if (sizeof(ResultTy) == 16)
v2 ^= 0xee;
else
v2 ^= 0xff;
@@ -144,10 +118,10 @@ int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
SIPROUND;
b = v0 ^ v1 ^ v2 ^ v3;
- U64TO8_LE(out, b);
- if (outlen == 8)
- return 0;
+ uint64_t firstHalf = b;
+ if (sizeof(ResultTy) == 8)
+ return firstHalf;
v1 ^= 0xdd;
@@ -155,7 +129,7 @@ int siphash(const void *in, const size_t inlen, const void *k, uint8_t *out,
SIPROUND;
b = v0 ^ v1 ^ v2 ^ v3;
- U64TO8_LE(out + 8, b);
+ uint64_t secondHalf = b;
- return 0;
+ return firstHalf | (ResultTy(secondHalf) << (sizeof(ResultTy) == 8 ? 0 : 64));
}
>From acb8f3c319165bac2315cabe735cd8beccac046e Mon Sep 17 00:00:00 2001
From: Ahmed Bougacha <ahmed at bougacha.org>
Date: Wed, 5 Jun 2024 10:12:28 -0700
Subject: [PATCH 4/4] Address review feedback.
- add back github link to ref. impl.
- add back function doc comment
- use anon. namespace
- use constexpr outlen, avoid or workaround
---
llvm/lib/Support/SipHash.cpp | 34 ++++++++++++++++++++++++----------
1 file changed, 24 insertions(+), 10 deletions(-)
diff --git a/llvm/lib/Support/SipHash.cpp b/llvm/lib/Support/SipHash.cpp
index ef882ae4d8745..fe6c28de2f591 100644
--- a/llvm/lib/Support/SipHash.cpp
+++ b/llvm/lib/Support/SipHash.cpp
@@ -9,8 +9,9 @@
#include "llvm/Support/Compiler.h"
#include <cstdint>
-// Lightly adapted from the SipHash reference C implementation by
-// Jean-Philippe Aumasson and Daniel J. Bernstein.
+// Lightly adapted from the SipHash reference C implementation:
+// https://github.com/veorq/SipHash
+// by Jean-Philippe Aumasson and Daniel J. Bernstein
#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
@@ -38,15 +39,26 @@
v2 = ROTL(v2, 32); \
} while (0)
+namespace {
+
+/// Computes a SipHash value
+///
+/// \param in: pointer to input data (read-only)
+/// \param inlen: input data length in bytes (any size_t value)
+/// \param k: reference to the key data 16-byte array (read-only)
+/// \returns output data, must be 8 or 16 bytes
+///
template <int cROUNDS, int dROUNDS, class ResultTy>
-static inline ResultTy siphash(const unsigned char *in, uint64_t inlen,
- const unsigned char (&k)[16]) {
+ResultTy siphash(const unsigned char *in, uint64_t inlen,
+ const unsigned char (&k)[16]) {
const unsigned char *ni = (const unsigned char *)in;
const unsigned char *kk = (const unsigned char *)k;
- static_assert(sizeof(ResultTy) == 8 || sizeof(ResultTy) == 16,
+ constexpr size_t outlen = sizeof(ResultTy);
+ static_assert(outlen == 8 || outlen == 16,
"result type should be uint64_t or uint128_t");
+
uint64_t v0 = UINT64_C(0x736f6d6570736575);
uint64_t v1 = UINT64_C(0x646f72616e646f6d);
uint64_t v2 = UINT64_C(0x6c7967656e657261);
@@ -63,7 +75,7 @@ static inline ResultTy siphash(const unsigned char *in, uint64_t inlen,
v1 ^= k1;
v0 ^= k0;
- if (sizeof(ResultTy) == 16)
+ if (outlen == 16)
v1 ^= 0xee;
for (; ni != end; ni += 8) {
@@ -109,7 +121,7 @@ static inline ResultTy siphash(const unsigned char *in, uint64_t inlen,
v0 ^= b;
- if (sizeof(ResultTy) == 16)
+ if (outlen == 16)
v2 ^= 0xee;
else
v2 ^= 0xff;
@@ -118,9 +130,9 @@ static inline ResultTy siphash(const unsigned char *in, uint64_t inlen,
SIPROUND;
b = v0 ^ v1 ^ v2 ^ v3;
-
uint64_t firstHalf = b;
- if (sizeof(ResultTy) == 8)
+
+ if (outlen == 8)
return firstHalf;
v1 ^= 0xdd;
@@ -131,5 +143,7 @@ static inline ResultTy siphash(const unsigned char *in, uint64_t inlen,
b = v0 ^ v1 ^ v2 ^ v3;
uint64_t secondHalf = b;
- return firstHalf | (ResultTy(secondHalf) << (sizeof(ResultTy) == 8 ? 0 : 64));
+ return firstHalf | (ResultTy(secondHalf) << 64);
}
+
+} // end anonymous namespace
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