ptest() was using this idea already.
As far as I can see, this is safe. Ttestsuite passes.
One downside is that a temporary from e.g. printf invocation
won't be freed until the next printf call.
function old new delta
awk_printf 481 468 -13
as_regex 137 111 -26
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-39) Total: -39 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
It seems to be designed to reduce overhead of malloc's auxiliary data,
by allocating at least 64 variables as a block.
With "struct var" being about 20-32 bytes long (32/64 bits),
malloc overhead for one temporary indeed is high, ~33% more memory used
than needed.
function old new delta
evaluate 3137 3145 +8
modprobe_main 798 803 +5
exec_builtin 1414 1419 +5
awk_printf 476 481 +5
as_regex 132 137 +5
EMSG_INTERNAL_ERROR 15 - -15
nvfree 169 116 -53
nvalloc 145 - -145
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 5/1 up/down: 28/-213) Total: -185 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
hash_find(): do not caclculate hash twice. Do not divide - can use
cheap multiply-by-8 shift.
nextword(): do not repeatedly increment in-memory value, do it in register,
then store final result.
hashwalk_init(): do not strlen() twice.
function old new delta
hash_search3 - 49 +49
hash_find 259 281 +22
nextword 19 16 -3
evaluate 3141 3137 -4
hash_search 54 28 -26
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/3 up/down: 71/-33) Total: 38 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
We can free them after they are no longer needed.
(Currently, being a NOEXEC applet is much larger waste of memory
for the case of long-running awk script).
function old new delta
awk_main 831 827 -4
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Accepting nonsense like "--4", and even "-- -4" is confusing.
function old new delta
parse_expr 917 938 +21
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Second reference to a field reallocs/moves Fields[] array, but first ref
still tries to use the element where it was before move.
function old new delta
fsrealloc 94 106 +12
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Treat the output of printf as binary rather than a null-terminated
string so that NUL characters can be output.
This is considered to be a GNU extension, though it's also available
in mawk and FreeBSD's awk.
function old new delta
evaluate 3487 3504 +17
awk_printf 504 519 +15
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 32/0) Total: 32 bytes
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Back in 2007, commit 0c97c9d437 ("'simple' error message functions by
Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower
overhead call to bb_perror_msg() when only a string was being printed
with no parameters. This saves space for some CPU architectures because
it avoids the overhead of a call to a variadic function. However there
has never been a simple version of bb_error_msg(), and since 2007 many
new calls to bb_perror_msg() have been added that only take a single
parameter and so could have been using bb_simple_perror_message().
This changeset introduces 'simple' versions of bb_info_msg(),
bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and
bb_herror_msg_and_die(), and replaces all calls that only take a
single parameter, or use something like ("%s", arg), with calls to the
corresponding 'simple' version.
Since it is likely that single parameter calls to the variadic functions
may be accidentally reintroduced in the future a new debugging config
option WARN_SIMPLE_MSG has been introduced. This uses some macro magic
which will cause any such calls to generate a warning, but this is
turned off by default to avoid use of the unpleasant macros in normal
circumstances.
This is a large changeset due to the number of calls that have been
replaced. The only files that contain changes other than simple
substitution of function calls are libbb.h, libbb/herror_msg.c,
libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c,
networking/udhcp/common.h and util-linux/mdev.c additonal macros have
been added for logging so that single parameter and multiple parameter
logging variants exist.
The amount of space saved varies considerably by architecture, and was
found to be as follows (for 'defconfig' using GCC 7.4):
Arm: -92 bytes
MIPS: -52 bytes
PPC: -1836 bytes
x86_64: -938 bytes
Note that for the MIPS architecture only an exception had to be made
disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h)
because it made these files larger on MIPS.
Signed-off-by: James Byrne <james.byrne@origamienergy.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Unlike exit and return, delete strictly requires an arg, and derefs a
null pointer if executed without one.
Signed-off-by: Brian Foley <bpfoley@google.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Avoids an uninit pointer deref for some malformed ternary exprs.
Add a test that would crash in busybox before this fix.
Signed-off-by: Brian Foley <bpfoley@google.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
