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Commit 69bda632 authored by Findit's avatar Findit Committed by Copybara-Service
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Revert "[zlib] Re-sync with zlib 1.2.12, patch 13 of N" 

This reverts commit 096d2447f2fdecf9693db32ba50858d5e31cca34.

Reason for revert:
Findit (https://goo.gl/kROfz5) identified this CL at revision 096d2447f2fdecf9693db32ba50858d5e31cca34 as
the culprit for failures in the continuous build including:

Sample Failed Build: https://ci.chromium.org/b/8815840511093637041
Sample Failed Step: compile

If it is a false positive, please report it at https://bugs.chromium.org/p/chromium/issues/entry?status=Available&comment=Datastore+key+for+the+culprit+entity%3A+chromium.googlesource.com%2Fchromium%2Fsrc%2Frefs%2Fheads%2Fmain%2F096d2447f2fdecf9693db32ba50858d5e31cca34&labels=Test-Findit-Wrong&components=Tools%3ETest%3EFindIt&summary=Wrongly+blame+096d2447f2fdecf9693db32ba50858d5e31cca34

Original change's description:
> [zlib] Re-sync with zlib 1.2.12, patch 13 of N
>
> Ported:
> - Add use of the ARMv8 crc32 instructions when requested.
> - Use ARM crc32 instructions if the ARM architecture has them.
> - Explicitly note that the 32-bit check values are 32 bits.
>
> Bug: 1032721
> Change-Id: Ic988198b20de6f59c5fbcd3d37a33d2594380b28
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3607170


> Reviewed-by: default avatarNoel Gordon <noel@chromium.org>
> Commit-Queue: Adenilson Cavalcanti <cavalcantii@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#996030}

Change-Id: Ic2edd4bdc8c8f5538414ce8e71b8666e271752df
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1032721
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3607182


Reviewed-by: default avatarChristopher Lam <calamity@chromium.org>
Commit-Queue: Christopher Lam <calamity@chromium.org>
Owners-Override: Christopher Lam <calamity@chromium.org>
Cr-Commit-Position: refs/heads/main@{#996033}
NOKEYCHECK=True
GitOrigin-RevId: 7acb20d251cd57c13e3f04fa41be7b9c83d06d5e
parent 1efc3c8f
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crc32.c
+ 0
− 118
View file @ 69bda632
......@@ -622,122 +622,6 @@ const z_crc_t FAR * ZEXPORT get_crc_table()
return (const z_crc_t FAR *)crc_table;
}
/* =========================================================================
* Use ARM machine instructions if available. This will compute the CRC about
* ten times faster than the braided calculation. This code does not check for
* the presence of the CRC instruction at run time. __ARM_FEATURE_CRC32 will
* only be defined if the compilation specifies an ARM processor architecture
* that has the instructions. For example, compiling with -march=armv8.1-a or
* -march=armv8-a+crc, or -march=native if the compile machine has the crc32
* instructions.
*/
#if defined(__aarch64__) && defined(__ARM_FEATURE_CRC32) && W == 8
/*
Constants empirically determined to maximize speed. These values are from
measurements on a Cortex-A57. Your mileage may vary.
*/
#define Z_BATCH 3990 /* number of words in a batch */
#define Z_BATCH_ZEROS 0xa10d3d0c /* computed from Z_BATCH = 3990 */
#define Z_BATCH_MIN 800 /* fewest words in a final batch */
unsigned long ZEXPORT crc32_z(crc, buf, len)
unsigned long crc;
const unsigned char FAR *buf;
z_size_t len;
{
z_crc_t val;
z_word_t crc1, crc2;
const z_word_t *word;
z_word_t val0, val1, val2;
z_size_t last, last2, i;
z_size_t num;
/* Return initial CRC, if requested. */
if (buf == Z_NULL) return 0;
#ifdef DYNAMIC_CRC_TABLE
once(&made, make_crc_table);
#endif /* DYNAMIC_CRC_TABLE */
/* Pre-condition the CRC */
crc ^= 0xffffffff;
/* Compute the CRC up to a word boundary. */
while (len && ((z_size_t)buf & 7) != 0) {
len--;
val = *buf++;
__asm__ volatile("crc32b %w0, %w0, %w1" : "+r"(crc) : "r"(val));
}
/* Prepare to compute the CRC on full 64-bit words word[0..num-1]. */
word = (z_word_t const *)buf;
num = len >> 3;
len &= 7;
/* Do three interleaved CRCs to realize the throughput of one crc32x
instruction per cycle. Each CRC is calcuated on Z_BATCH words. The three
CRCs are combined into a single CRC after each set of batches. */
while (num >= 3 * Z_BATCH) {
crc1 = 0;
crc2 = 0;
for (i = 0; i < Z_BATCH; i++) {
val0 = word[i];
val1 = word[i + Z_BATCH];
val2 = word[i + 2 * Z_BATCH];
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc) : "r"(val0));
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc1) : "r"(val1));
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc2) : "r"(val2));
}
word += 3 * Z_BATCH;
num -= 3 * Z_BATCH;
crc = multmodp(Z_BATCH_ZEROS, crc) ^ crc1;
crc = multmodp(Z_BATCH_ZEROS, crc) ^ crc2;
}
/* Do one last smaller batch with the remaining words, if there are enough
to pay for the combination of CRCs. */
last = num / 3;
if (last >= Z_BATCH_MIN) {
last2 = last << 1;
crc1 = 0;
crc2 = 0;
for (i = 0; i < last; i++) {
val0 = word[i];
val1 = word[i + last];
val2 = word[i + last2];
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc) : "r"(val0));
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc1) : "r"(val1));
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc2) : "r"(val2));
}
word += 3 * last;
num -= 3 * last;
val = x2nmodp(last, 6);
crc = multmodp(val, crc) ^ crc1;
crc = multmodp(val, crc) ^ crc2;
}
/* Compute the CRC on any remaining words. */
for (i = 0; i < num; i++) {
val0 = word[i];
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc) : "r"(val0));
}
word += num;
/* Complete the CRC on any remaining bytes. */
buf = (const unsigned char FAR *)word;
while (len) {
len--;
val = *buf++;
__asm__ volatile("crc32b %w0, %w0, %w1" : "+r"(crc) : "r"(val));
}
/* Return the CRC, post-conditioned. */
return crc ^ 0xffffffff;
}
#else
/* ========================================================================= */
unsigned long ZEXPORT crc32_z(crc, buf, len)
unsigned long crc;
......@@ -1090,8 +974,6 @@ unsigned long ZEXPORT crc32_z(crc, buf, len)
return crc ^ 0xffffffff;
}
#endif
/* ========================================================================= */
unsigned long ZEXPORT crc32(crc, buf, len)
unsigned long crc;
......
zlib.h
+ 5
− 7
View file @ 69bda632
......@@ -1690,9 +1690,8 @@ ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
/*
Update a running Adler-32 checksum with the bytes buf[0..len-1] and
return the updated checksum. An Adler-32 value is in the range of a 32-bit
unsigned integer. If buf is Z_NULL, this function returns the required
initial value for the checksum.
return the updated checksum. If buf is Z_NULL, this function returns the
required initial value for the checksum.
An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
much faster.
......@@ -1728,10 +1727,9 @@ ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
/*
Update a running CRC-32 with the bytes buf[0..len-1] and return the
updated CRC-32. A CRC-32 value is in the range of a 32-bit unsigned integer.
If buf is Z_NULL, this function returns the required initial value for the
crc. Pre- and post-conditioning (one's complement) is performed within this
function so it shouldn't be done by the application.
updated CRC-32. If buf is Z_NULL, this function returns the required
initial value for the crc. Pre- and post-conditioning (one's complement) is
performed within this function so it shouldn't be done by the application.
Usage example:
......
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