From a978e26b8338e044dbc5e0f4624f2fe047eec5df Mon Sep 17 00:00:00 2001
From: Ian Lance Taylor <iant@golang.org>
Date: Thu, 5 Oct 2017 16:39:38 +0000
Subject: [PATCH] elf.c (elf_zlib_fetch): Change pval argument to uint64_t *.
* elf.c (elf_zlib_fetch): Change pval argument to uint64_t *.
Read a four byte integer.
(elf_zlib_inflate): Change val to uint64_t. Align pin to a 32-bit
boundary before ever calling elf_zlib_fetch.
* ztest.c (test_large): Simplify print statements a bit.
From-SVN: r253456
---
libbacktrace/ChangeLog | 8 +++++++
libbacktrace/elf.c | 49 +++++++++++++++++++++++++++++++-----------
libbacktrace/ztest.c | 6 +++---
3 files changed, 47 insertions(+), 16 deletions(-)
diff --git a/libbacktrace/ChangeLog b/libbacktrace/ChangeLog
index 27024b7ea40f..7aadc7353ef2 100644
--- a/libbacktrace/ChangeLog
+++ b/libbacktrace/ChangeLog
@@ -1,3 +1,11 @@
+2017-10-05 Ian Lance Taylor <iant@golang.org>
+
+ * elf.c (elf_zlib_fetch): Change pval argument to uint64_t *.
+ Read a four byte integer.
+ (elf_zlib_inflate): Change val to uint64_t. Align pin to a 32-bit
+ boundary before ever calling elf_zlib_fetch.
+ * ztest.c (test_large): Simplify print statements a bit.
+
2017-10-02 Ian Lance Taylor <iant@golang.org>
* ztest.c: #include <errno.h>.
diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c
index bfedca9a9cbb..06823fcf59b6 100644
--- a/libbacktrace/elf.c
+++ b/libbacktrace/elf.c
@@ -1031,11 +1031,12 @@ elf_zlib_failed(void)
static int
elf_zlib_fetch (const unsigned char **ppin, const unsigned char *pinend,
- uint32_t *pval, unsigned int *pbits)
+ uint64_t *pval, unsigned int *pbits)
{
unsigned int bits;
const unsigned char *pin;
- uint32_t val;
+ uint64_t val;
+ uint32_t next;
bits = *pbits;
if (bits >= 15)
@@ -1043,20 +1044,25 @@ elf_zlib_fetch (const unsigned char **ppin, const unsigned char *pinend,
pin = *ppin;
val = *pval;
- if (unlikely (pinend - pin < 2))
+ if (unlikely (pinend - pin < 4))
{
elf_zlib_failed ();
return 0;
}
- val |= pin[0] << bits;
- val |= pin[1] << (bits + 8);
- bits += 16;
- pin += 2;
- /* We will need the next two bytes soon. We ask for high temporal
- locality because we will need the whole cache line soon. */
- __builtin_prefetch (pin, 0, 3);
- __builtin_prefetch (pin + 1, 0, 3);
+ /* We've ensured that PIN is aligned. */
+ next = *(const uint32_t *)pin;
+
+#if __BYTE_ORDER == __ORDER_BIG_ENDIAN
+ next = __builtin_bswap32 (next);
+#endif
+
+ val |= (uint64_t)next << bits;
+ bits += 32;
+ pin += 4;
+
+ /* We will need the next four bytes soon. */
+ __builtin_prefetch (pin, 0, 0);
*ppin = pin;
*pval = val;
@@ -1566,7 +1572,7 @@ elf_zlib_inflate (const unsigned char *pin, size_t sin, uint16_t *zdebug_table,
poutend = pout + sout;
while ((pinend - pin) > 4)
{
- uint32_t val;
+ uint64_t val;
unsigned int bits;
int last;
@@ -1601,10 +1607,19 @@ elf_zlib_inflate (const unsigned char *pin, size_t sin, uint16_t *zdebug_table,
}
pin += 2;
- /* Read blocks until one is marked last. */
+ /* Align PIN to a 32-bit boundary. */
val = 0;
bits = 0;
+ while ((((uintptr_t) pin) & 3) != 0)
+ {
+ val |= (uint64_t)*pin << bits;
+ bits += 8;
+ ++pin;
+ }
+
+ /* Read blocks until one is marked last. */
+
last = 0;
while (!last)
@@ -1671,6 +1686,14 @@ elf_zlib_inflate (const unsigned char *pin, size_t sin, uint16_t *zdebug_table,
pout += len;
pin += len;
+ /* Align PIN. */
+ while ((((uintptr_t) pin) & 3) != 0)
+ {
+ val |= (uint64_t)*pin << bits;
+ bits += 8;
+ ++pin;
+ }
+
/* Go around to read the next block. */
continue;
}
diff --git a/libbacktrace/ztest.c b/libbacktrace/ztest.c
index e2ab524825ca..7226d6a0a36c 100644
--- a/libbacktrace/ztest.c
+++ b/libbacktrace/ztest.c
@@ -432,9 +432,9 @@ test_large (struct backtrace_state *state)
ctime = average_time (ctimes, trials);
ztime = average_time (ztimes, trials);
- printf ("backtrace time: %zu ns\n", ctime);
- printf ("zlib time: : %zu ns\n", ztime);
- printf ("percentage : %g\n", (double) ztime / (double) ctime);
+ printf ("backtrace: %zu ns\n", ctime);
+ printf ("zlib : %zu ns\n", ztime);
+ printf ("ratio : %g\n", (double) ztime / (double) ctime);
return;
--
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