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3de3f57c6

Denys Vlasenko

2009-09-06

FAILED Duration: 28s

Subject

Revert "unlzma: speedup, by Pascal Bellard (pascal.bellard AT ads-lu.com)"

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

archival/Config.in +2 -2 archival/libunarchive/decompress_unlzma.c +96 -58

archival/Config.in+2 -2

@@ -298,8 +298,8 @@ config FEATURE_LZMA_FAST
	default n
	depends on UNLZMA
	help
-	This option reduces decompression time by about 25% at the cost of
-	a 1K bigger binary.
+	This option reduces decompression time by about 33% at the cost of
+	a 2K bigger binary.

	config UNZIP
	bool "unzip"

archival/libunarchive/decompress_unlzma.c+96 -58

@@ -8,15 +8,14 @@
	*
	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
	*/
+
	#include "libbb.h"
	#include "unarchive.h"

	#if ENABLE_FEATURE_LZMA_FAST
	# define speed_inline ALWAYS_INLINE
-	# define size_inline
	#else
	# define speed_inline
-	# define size_inline ALWAYS_INLINE
	#endif


@@ -45,8 +44,8 @@ typedef struct {
	#define RC_MODEL_TOTAL_BITS 11


-	/* Called twice: once at startup (LZMA_FAST only) and once in rc_normalize() */
-	static size_inline void rc_read(rc_t *rc)
+	/* Called twice: once at startup and once in rc_normalize() */
+	static void rc_read(rc_t *rc)
	{
	int buffer_size = safe_read(rc->fd, RC_BUFFER, RC_BUFFER_SIZE);
	if (buffer_size <= 0)
@@ -55,17 +54,8 @@ static size_inline void rc_read(rc_t *rc)
	rc->buffer_end = RC_BUFFER + buffer_size;
	}

-	/* Called twice, but one callsite is in speed_inline'd rc_is_bit_1() */
-	static void rc_do_normalize(rc_t *rc)
-	{
-	if (rc->ptr >= rc->buffer_end)
-	rc_read(rc);
-	rc->range <<= 8;
-	rc->code = (rc->code << 8) \| *rc->ptr++;
-	}
-
	/* Called once */
-	static ALWAYS_INLINE rc_t* rc_init(int fd) /, int buffer_size) /
+	static rc_t* rc_init(int fd) /, int buffer_size) /
	{
	int i;
	rc_t *rc;
@@ -73,18 +63,17 @@ static ALWAYS_INLINE rc_t* rc_init(int fd) /, int buffer_size) /
	rc = xmalloc(sizeof(*rc) + RC_BUFFER_SIZE);

	rc->fd = fd;
+	/* rc->buffer_size = buffer_size; */
+	rc->buffer_end = RC_BUFFER + RC_BUFFER_SIZE;
	rc->ptr = rc->buffer_end;

+	rc->code = 0;
+	rc->range = 0xFFFFFFFF;
	for (i = 0; i < 5; i++) {
-	#if ENABLE_FEATURE_LZMA_FAST
	if (rc->ptr >= rc->buffer_end)
	rc_read(rc);
	rc->code = (rc->code << 8) \| *rc->ptr++;
-	#else
-	rc_do_normalize(rc);
-	#endif
	}
-	rc->range = 0xFFFFFFFF;
	return rc;
	}

@@ -94,6 +83,14 @@ static ALWAYS_INLINE void rc_free(rc_t *rc)
	free(rc);
	}

+	/* Called twice, but one callsite is in speed_inline'd rc_is_bit_0_helper() */
+	static void rc_do_normalize(rc_t *rc)
+	{
+	if (rc->ptr >= rc->buffer_end)
+	rc_read(rc);
+	rc->range <<= 8;
+	rc->code = (rc->code << 8) \| *rc->ptr++;
+	}
	static ALWAYS_INLINE void rc_normalize(rc_t *rc)
	{
	if (rc->range < (1 << RC_TOP_BITS)) {
@@ -101,28 +98,49 @@ static ALWAYS_INLINE void rc_normalize(rc_t *rc)
	}
	}

-	/* rc_is_bit_1 is called 9 times */
-	static speed_inline int rc_is_bit_1(rc_t rc, uint16_t p)
+	/* rc_is_bit_0 is called 9 times */
+	/* Why rc_is_bit_0_helper exists?
+	* Because we want to always expose (rc->code < rc->bound) to optimizer.
+	* Thus rc_is_bit_0 is always inlined, and rc_is_bit_0_helper is inlined
+	* only if we compile for speed.
+	*/
+	static speed_inline uint32_t rc_is_bit_0_helper(rc_t rc, uint16_t p)
	{
	rc_normalize(rc);
	rc->bound = p (rc->range >> RC_MODEL_TOTAL_BITS);
-	if (rc->code < rc->bound) {
-	rc->range = rc->bound;
-	p += ((1 << RC_MODEL_TOTAL_BITS) - p) >> RC_MOVE_BITS;
-	return 0;
-	}
+	return rc->bound;
+	}
+	static ALWAYS_INLINE int rc_is_bit_0(rc_t rc, uint16_t p)
+	{
+	uint32_t t = rc_is_bit_0_helper(rc, p);
+	return rc->code < t;
+	}
+
+	/* Called ~10 times, but very small, thus inlined */
+	static speed_inline void rc_update_bit_0(rc_t rc, uint16_t p)
+	{
+	rc->range = rc->bound;
+	p += ((1 << RC_MODEL_TOTAL_BITS) - p) >> RC_MOVE_BITS;
+	}
+	static speed_inline void rc_update_bit_1(rc_t rc, uint16_t p)
+	{
	rc->range -= rc->bound;
	rc->code -= rc->bound;
	p -= p >> RC_MOVE_BITS;
-	return 1;
	}

	/* Called 4 times in unlzma loop */
-	static speed_inline int rc_get_bit(rc_t rc, uint16_t p, int *symbol)
+	static int rc_get_bit(rc_t rc, uint16_t p, int *symbol)
	{
-	int ret = rc_is_bit_1(rc, p);
-	symbol = symbol * 2 + ret;
-	return ret;
+	if (rc_is_bit_0(rc, p)) {
+	rc_update_bit_0(rc, p);
+	symbol = 2;
+	return 0;
+	} else {
+	rc_update_bit_1(rc, p);
+	symbol = symbol * 2 + 1;
+	return 1;
+	}
	}

	/* Called once */
@@ -248,13 +266,13 @@ unpack_lzma_stream(int src_fd, int dst_fd)
	header.dst_size = SWAP_LE64(header.dst_size);

	if (header.dict_size == 0)
-	header.dict_size++;
+	header.dict_size = 1;

	buffer = xmalloc(MIN(header.dst_size, header.dict_size));

	num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
	p = xmalloc(num_probs * sizeof(*p));
-	num_probs += LZMA_LITERAL - LZMA_BASE_SIZE;
+	num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
	for (i = 0; i < num_probs; i++)
	p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;

@@ -264,8 +282,9 @@ unpack_lzma_stream(int src_fd, int dst_fd)
	int pos_state = (buffer_pos + global_pos) & pos_state_mask;

	prob = p + LZMA_IS_MATCH + (state << LZMA_NUM_POS_BITS_MAX) + pos_state;
-	if (!rc_is_bit_1(rc, prob)) {
+	if (rc_is_bit_0(rc, prob)) {
	mi = 1;
+	rc_update_bit_0(rc, prob);
	prob = (p + LZMA_LITERAL
	+ (LZMA_LIT_SIZE * ((((buffer_pos + global_pos) & literal_pos_mask) << lc)
	+ (previous_byte >> (8 - lc))
@@ -321,21 +340,27 @@ unpack_lzma_stream(int src_fd, int dst_fd)
	int offset;
	uint16_t *prob_len;

+	rc_update_bit_1(rc, prob);
	prob = p + LZMA_IS_REP + state;
-	if (!rc_is_bit_1(rc, prob)) {
+	if (rc_is_bit_0(rc, prob)) {
+	rc_update_bit_0(rc, prob);
	rep3 = rep2;
	rep2 = rep1;
	rep1 = rep0;
	state = state < LZMA_NUM_LIT_STATES ? 0 : 3;
	prob = p + LZMA_LEN_CODER;
	} else {
-	prob += LZMA_IS_REP_G0 - LZMA_IS_REP;
-	if (!rc_is_bit_1(rc, prob)) {
+	rc_update_bit_1(rc, prob);
+	prob = p + LZMA_IS_REP_G0 + state;
+	if (rc_is_bit_0(rc, prob)) {
+	rc_update_bit_0(rc, prob);
	prob = (p + LZMA_IS_REP_0_LONG
	+ (state << LZMA_NUM_POS_BITS_MAX)
	+ pos_state
	);
-	if (!rc_is_bit_1(rc, prob)) {
+	if (rc_is_bit_0(rc, prob)) {
+	rc_update_bit_0(rc, prob);
+
	state = state < LZMA_NUM_LIT_STATES ? 9 : 11;
	#if ENABLE_FEATURE_LZMA_FAST
	pos = buffer_pos - rep0;
@@ -347,16 +372,25 @@ unpack_lzma_stream(int src_fd, int dst_fd)
	len = 1;
	goto string;
	#endif
+	} else {
+	rc_update_bit_1(rc, prob);
	}
	} else {
	uint32_t distance;

-	prob += LZMA_IS_REP_G1 - LZMA_IS_REP_G0;
-	distance = rep1;
-	if (rc_is_bit_1(rc, prob)) {
-	prob += LZMA_IS_REP_G2 - LZMA_IS_REP_G1;
-	distance = rep2;
-	if (rc_is_bit_1(rc, prob)) {
+	rc_update_bit_1(rc, prob);
+	prob = p + LZMA_IS_REP_G1 + state;
+	if (rc_is_bit_0(rc, prob)) {
+	rc_update_bit_0(rc, prob);
+	distance = rep1;
+	} else {
+	rc_update_bit_1(rc, prob);
+	prob = p + LZMA_IS_REP_G2 + state;
+	if (rc_is_bit_0(rc, prob)) {
+	rc_update_bit_0(rc, prob);
+	distance = rep2;
+	} else {
+	rc_update_bit_1(rc, prob);
	distance = rep3;
	rep3 = rep2;
	}
@@ -370,20 +404,24 @@ unpack_lzma_stream(int src_fd, int dst_fd)
	}

	prob_len = prob + LZMA_LEN_CHOICE;
-	if (!rc_is_bit_1(rc, prob_len)) {
-	prob_len += LZMA_LEN_LOW - LZMA_LEN_CHOICE
-	+ (pos_state << LZMA_LEN_NUM_LOW_BITS);
+	if (rc_is_bit_0(rc, prob_len)) {
+	rc_update_bit_0(rc, prob_len);
+	prob_len = (prob + LZMA_LEN_LOW
+	+ (pos_state << LZMA_LEN_NUM_LOW_BITS));
	offset = 0;
	num_bits = LZMA_LEN_NUM_LOW_BITS;
	} else {
-	prob_len += LZMA_LEN_CHOICE_2 - LZMA_LEN_CHOICE;
-	if (!rc_is_bit_1(rc, prob_len)) {
-	prob_len += LZMA_LEN_MID - LZMA_LEN_CHOICE_2
-	+ (pos_state << LZMA_LEN_NUM_MID_BITS);
+	rc_update_bit_1(rc, prob_len);
+	prob_len = prob + LZMA_LEN_CHOICE_2;
+	if (rc_is_bit_0(rc, prob_len)) {
+	rc_update_bit_0(rc, prob_len);
+	prob_len = (prob + LZMA_LEN_MID
+	+ (pos_state << LZMA_LEN_NUM_MID_BITS));
	offset = 1 << LZMA_LEN_NUM_LOW_BITS;
	num_bits = LZMA_LEN_NUM_MID_BITS;
	} else {
-	prob_len += LZMA_LEN_HIGH - LZMA_LEN_CHOICE_2;
+	rc_update_bit_1(rc, prob_len);
+	prob_len = prob + LZMA_LEN_HIGH;
	offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
	+ (1 << LZMA_LEN_NUM_MID_BITS));
	num_bits = LZMA_LEN_NUM_HIGH_BITS;
@@ -400,20 +438,19 @@ unpack_lzma_stream(int src_fd, int dst_fd)
	((len < LZMA_NUM_LEN_TO_POS_STATES ? len :
	LZMA_NUM_LEN_TO_POS_STATES - 1)
	<< LZMA_NUM_POS_SLOT_BITS);
-	rc_bit_tree_decode(rc, prob,
-	LZMA_NUM_POS_SLOT_BITS, &pos_slot);
-	rep0 = pos_slot;
+	rc_bit_tree_decode(rc, prob, LZMA_NUM_POS_SLOT_BITS,
+	&pos_slot);
	if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
	num_bits = (pos_slot >> 1) - 1;
	rep0 = 2 \| (pos_slot & 1);
-	prob = p + LZMA_ALIGN;
	if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
	rep0 <<= num_bits;
-	prob += LZMA_SPEC_POS - LZMA_ALIGN - 1 + rep0 - pos_slot;
+	prob = p + LZMA_SPEC_POS + rep0 - pos_slot - 1;
	} else {
	num_bits -= LZMA_NUM_ALIGN_BITS;
	while (num_bits--)
	rep0 = (rep0 << 1) \| rc_direct_bit(rc);
+	prob = p + LZMA_ALIGN;
	rep0 <<= LZMA_NUM_ALIGN_BITS;
	num_bits = LZMA_NUM_ALIGN_BITS;
	}
@@ -424,7 +461,8 @@ unpack_lzma_stream(int src_fd, int dst_fd)
	rep0 \|= i;
	i <<= 1;
	}
-	}
+	} else
+	rep0 = pos_slot;
	if (++rep0 == 0)
	break;
	}