From: Oleg Tolmatcev <oleg.tolmatcev@gmail.com>
To: binutils@sourceware.org
Subject: [PATCH] make coff_compute_checksum faster
Date: Thu, 27 Apr 2023 20:24:48 +0200 [thread overview]
Message-ID: <CACcXsZjzrLPP5Ngo2bt20hkCQF+uvZ2syNvz5rW-bha_mDTfQw@mail.gmail.com> (raw)
This makes linking faster by reading 8 MB of data at once instead of
reading 2 bytes at once. This drastically reduces the number of system
calls.
---
bfd/coffcode.h | 52 ++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 44 insertions(+), 8 deletions(-)
diff --git a/bfd/coffcode.h b/bfd/coffcode.h
index 19a5ce18..8118ff47 100644
--- a/bfd/coffcode.h
+++ b/bfd/coffcode.h
@@ -3361,30 +3361,66 @@ coff_read_word (bfd *abfd, unsigned int
*value, unsigned int *pelength)
return true;
}
+static bool
+coff_read_word_from_buffer (unsigned char *b, int buf_size,
+ unsigned int *value, unsigned int *pelength)
+{
+
+ if (buf_size < 1)
+ {
+ *value = 0;
+ return false;
+ }
+
+ if (buf_size == 1)
+ *value = (unsigned int)b[0];
+ else
+ *value = (unsigned int)(b[0] + (b[1] << 8));
+
+ *pelength += buf_size == 1 ? 1 : 2;
+
+ return true;
+}
+
static unsigned int
coff_compute_checksum (bfd *abfd, unsigned int *pelength)
{
- bool more_data;
file_ptr filepos;
unsigned int value;
unsigned int total;
+ unsigned char *buf;
+ unsigned char *cur_buf;
+ int buf_size;
+ int cur_buf_size;
total = 0;
*pelength = 0;
- filepos = (file_ptr) 0;
+ filepos = (file_ptr)0;
+ buf = (unsigned char *)bfd_malloc (0x800000);
+ if (buf == NULL)
+ return 0;
do
{
if (bfd_seek (abfd, filepos, SEEK_SET) != 0)
- return 0;
+ return 0;
- more_data = coff_read_word (abfd, &value, pelength);
- total += value;
- total = 0xffff & (total + (total >> 0x10));
- filepos += 2;
+ buf_size = bfd_bread (buf, 0x800000, abfd);
+ cur_buf_size = buf_size;
+ cur_buf = buf;
+ while (cur_buf_size > 0)
+ {
+ coff_read_word_from_buffer (cur_buf, cur_buf_size, &value, pelength);
+ cur_buf += 2;
+ cur_buf_size -= 2;
+ total += value;
+ total = 0xffff & (total + (total >> 0x10));
+ }
+ filepos += buf_size;
}
- while (more_data);
+ while (buf_size > 0);
+ free (buf);
return (0xffff & (total + (total >> 0x10)));
}
--
2.40.0.windows.1
next reply other threads:[~2023-04-27 18:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-27 18:24 Oleg Tolmatcev [this message]
2023-05-03 14:39 ` Nick Clifton
2023-05-03 18:10 ` Oleg Tolmatcev
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