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Unified Diff: third_party/zlib/fill_window_sse.c

Issue 677713002: Reland "Integrate SIMD optimisations for zlib" (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Add MSan suppression, prevent crc_fold_copy reading outside allocated memory, inline insert_string_… Created 6 years, 2 months ago
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Index: third_party/zlib/fill_window_sse.c
diff --git a/third_party/zlib/fill_window_sse.c b/third_party/zlib/fill_window_sse.c
new file mode 100644
index 0000000000000000000000000000000000000000..949ccce1ba9ccc83ceb07922428b22b6c8eb6ca1
--- /dev/null
+++ b/third_party/zlib/fill_window_sse.c
@@ -0,0 +1,175 @@
+/*
+ * Fill Window with SSE2-optimized hash shifting
+ *
+ * Copyright (C) 2013 Intel Corporation
+ * Authors:
+ * Arjan van de Ven <arjan@linux.intel.com>
+ * Jim Kukunas <james.t.kukunas@linux.intel.com>
+ *
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+#include <immintrin.h>
+#include "deflate.h"
+
+#define UPDATE_HASH(s,h,i) \
+ {\
+ if (s->level < 6) { \
+ h = (3483 * (s->window[i]) +\
+ 23081* (s->window[i+1]) +\
+ 6954 * (s->window[i+2]) +\
+ 20947* (s->window[i+3])) & s->hash_mask;\
+ } else {\
+ h = (25881* (s->window[i]) +\
+ 24674* (s->window[i+1]) +\
+ 25811* (s->window[i+2])) & s->hash_mask;\
+ }\
+ }\
+
+extern int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
+
+void fill_window_sse(deflate_state *s)
+{
+ const __m128i xmm_wsize = _mm_set1_epi16(s->w_size);
+
+ register unsigned n;
+ register Posf *p;
+ unsigned more; /* Amount of free space at the end of the window. */
+ uInt wsize = s->w_size;
+
+ Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead");
+
+ do {
+ more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
+
+ /* Deal with !@#$% 64K limit: */
+ if (sizeof(int) <= 2) {
+ if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
+ more = wsize;
+
+ } else if (more == (unsigned)(-1)) {
+ /* Very unlikely, but possible on 16 bit machine if
+ * strstart == 0 && lookahead == 1 (input done a byte at time)
+ */
+ more--;
+ }
+ }
+
+ /* If the window is almost full and there is insufficient lookahead,
+ * move the upper half to the lower one to make room in the upper half.
+ */
+ if (s->strstart >= wsize+MAX_DIST(s)) {
+
+ zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
+ s->match_start -= wsize;
+ s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
+ s->block_start -= (long) wsize;
+
+ /* Slide the hash table (could be avoided with 32 bit values
+ at the expense of memory usage). We slide even when level == 0
+ to keep the hash table consistent if we switch back to level > 0
+ later. (Using level 0 permanently is not an optimal usage of
+ zlib, so we don't care about this pathological case.)
+ */
+ n = s->hash_size;
+ p = &s->head[n];
+ p -= 8;
+ do {
+ __m128i value, result;
+
+ value = _mm_loadu_si128((__m128i *)p);
+ result = _mm_subs_epu16(value, xmm_wsize);
+ _mm_storeu_si128((__m128i *)p, result);
+
+ p -= 8;
+ n -= 8;
+ } while (n > 0);
+
+ n = wsize;
+#ifndef FASTEST
+ p = &s->prev[n];
+ p -= 8;
+ do {
+ __m128i value, result;
+
+ value = _mm_loadu_si128((__m128i *)p);
+ result = _mm_subs_epu16(value, xmm_wsize);
+ _mm_storeu_si128((__m128i *)p, result);
+
+ p -= 8;
+ n -= 8;
+ } while (n > 0);
+#endif
+ more += wsize;
+ }
+ if (s->strm->avail_in == 0) break;
+
+ /* If there was no sliding:
+ * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
+ * more == window_size - lookahead - strstart
+ * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
+ * => more >= window_size - 2*WSIZE + 2
+ * In the BIG_MEM or MMAP case (not yet supported),
+ * window_size == input_size + MIN_LOOKAHEAD &&
+ * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
+ * Otherwise, window_size == 2*WSIZE so more >= 2.
+ * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
+ */
+ Assert(more >= 2, "more < 2");
+
+ n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
+ s->lookahead += n;
+
+ /* Initialize the hash value now that we have some input: */
+ if (s->lookahead >= MIN_MATCH) {
+ uInt str = s->strstart;
+ s->ins_h = s->window[str];
+ if (str >= 1)
+ UPDATE_HASH(s, s->ins_h, str + 1 - (MIN_MATCH-1));
+#if MIN_MATCH != 3
+ Call UPDATE_HASH() MIN_MATCH-3 more times
+#endif
+ }
+ /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
+ * but this is not important since only literal bytes will be emitted.
+ */
+
+ } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
+
+ /* If the WIN_INIT bytes after the end of the current data have never been
+ * written, then zero those bytes in order to avoid memory check reports of
+ * the use of uninitialized (or uninitialised as Julian writes) bytes by
+ * the longest match routines. Update the high water mark for the next
+ * time through here. WIN_INIT is set to MAX_MATCH since the longest match
+ * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
+ */
+ if (s->high_water < s->window_size) {
+ ulg curr = s->strstart + (ulg)(s->lookahead);
+ ulg init;
+
+ if (s->high_water < curr) {
+ /* Previous high water mark below current data -- zero WIN_INIT
+ * bytes or up to end of window, whichever is less.
+ */
+ init = s->window_size - curr;
+ if (init > WIN_INIT)
+ init = WIN_INIT;
+ zmemzero(s->window + curr, (unsigned)init);
+ s->high_water = curr + init;
+ }
+ else if (s->high_water < (ulg)curr + WIN_INIT) {
+ /* High water mark at or above current data, but below current data
+ * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
+ * to end of window, whichever is less.
+ */
+ init = (ulg)curr + WIN_INIT - s->high_water;
+ if (init > s->window_size - s->high_water)
+ init = s->window_size - s->high_water;
+ zmemzero(s->window + s->high_water, (unsigned)init);
+ s->high_water += init;
+ }
+ }
+
+ Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
+ "not enough room for search");
+}

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