The current checkstack.pl script has a few problems, stemming from the
overly simplistic attempt at parsing objdump output with regular
expresions: For example, on x86_64 it doesn't take the push
instruction into account, making it consistently underestimate the
real stack use, and it also doesn't capture stack pointer adjustments
of exactly 128 bytes [1].
Since newer gcc (>= 4.6) knows about -fstack-usage, we might as well
take the information straight from the horse's mouth. This patch
introduces scripts/stackusage, which is a simple wrapper for running
make with EXTRA_CFLAGS set to -fstack-usage. Example use is
scripts/stackusage -o out.su -- -j8 fs/ext4/
Arguments after -- are passed to make. Afterwards, we find all newly
created .su files, massage them a little, sort by stack use and
concatenate the result to a single output file.
[1] Since gcc encodes that by
48 83 c4 80 add $0xffffffffffffff80,%rsp
and not
48 81 ec 80 00 00 00 sub $0x80,%rsp
since -128 fits in an imm8.
Signed-off-by: Rasmus Villemoes <[email protected]>
---
scripts/stackusage | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
create mode 100755 scripts/stackusage
diff --git a/scripts/stackusage b/scripts/stackusage
new file mode 100755
index 000000000000..d631af648ae7
--- /dev/null
+++ b/scripts/stackusage
@@ -0,0 +1,40 @@
+#!/bin/sh
+
+outfile=""
+now=`date +%s`
+
+while [ $# -gt 0 ]
+do
+ case "$1" in
+ -o)
+ outfile="$2"
+ echo "$outfile"
+ shift 2;;
+ -h)
+ echo "usage: $0 [-o outfile] -- <make options/args>"
+ exit 0;;
+ --)
+ shift
+ break;;
+ -*)
+ echo >&2 "usage: $0 [-o outfile] -- <make options/args>"
+ exit 1;;
+ *) break;;
+ esac
+done
+
+if [ -z "$outfile" ]
+then
+ outfile=`mktemp --tmpdir stackusage.$$.XXXX`
+fi
+
+make EXTRA_CFLAGS="-fstack-usage" "$@"
+
+# Prepend directory name to file names, remove line/column
+# information, make file/function/size/type properly tab-separated.
+find . -name '*.su' -newermt "@${now}" -print | \
+ xargs perl -MFile::Basename -pe \
+ '$d = dirname($ARGV); s#([^:]+):([0-9]+:){2}#$d/$1\t#;' | \
+ sort -k3,3nr > "${outfile}"
+
+echo "$0: output written to ${outfile}"
--
2.1.3
On 2015-06-21 03:10, Rasmus Villemoes wrote:
> The current checkstack.pl script has a few problems, stemming from the
> overly simplistic attempt at parsing objdump output with regular
> expresions: For example, on x86_64 it doesn't take the push
> instruction into account, making it consistently underestimate the
> real stack use, and it also doesn't capture stack pointer adjustments
> of exactly 128 bytes [1].
>
> Since newer gcc (>= 4.6) knows about -fstack-usage, we might as well
> take the information straight from the horse's mouth. This patch
> introduces scripts/stackusage, which is a simple wrapper for running
> make with EXTRA_CFLAGS set to -fstack-usage. Example use is
>
> scripts/stackusage -o out.su -- -j8 fs/ext4/
>
> Arguments after -- are passed to make. Afterwards, we find all newly
> created .su files, massage them a little, sort by stack use and
> concatenate the result to a single output file.
>
> [1] Since gcc encodes that by
>
> 48 83 c4 80 add $0xffffffffffffff80,%rsp
>
> and not
>
> 48 81 ec 80 00 00 00 sub $0x80,%rsp
>
> since -128 fits in an imm8.
>
> Signed-off-by: Rasmus Villemoes <[email protected]>
> ---
> scripts/stackusage | 40 ++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 40 insertions(+)
> create mode 100755 scripts/stackusage
>
> diff --git a/scripts/stackusage b/scripts/stackusage
> new file mode 100755
> index 000000000000..d631af648ae7
> --- /dev/null
> +++ b/scripts/stackusage
> @@ -0,0 +1,40 @@
> +#!/bin/sh
> +
> +outfile=""
> +now=`date +%s`
> +
> +while [ $# -gt 0 ]
> +do
> + case "$1" in
> + -o)
> + outfile="$2"
> + echo "$outfile"
> + shift 2;;
> + -h)
> + echo "usage: $0 [-o outfile] -- <make options/args>"
> + exit 0;;
> + --)
> + shift
> + break;;
> + -*)
> + echo >&2 "usage: $0 [-o outfile] -- <make options/args>"
> + exit 1;;
> + *) break;;
> + esac
> +done
> +
> +if [ -z "$outfile" ]
> +then
> + outfile=`mktemp --tmpdir stackusage.$$.XXXX`
> +fi
> +
> +make EXTRA_CFLAGS="-fstack-usage" "$@"
EXTRA_CFLAGS is reserved for use by Makefiles, please use KCFLAGS
instead. I wonder whether it worked at all, because EXTRA_CFLAGS is
reset by scripts/Makefile.build.
Michal
On Tue, Jun 23 2015, Michal Marek <[email protected]> wrote:
>
> EXTRA_CFLAGS is reserved for use by Makefiles, please use KCFLAGS
> instead.
Will do, thanks. Maybe Documentation/SubmitChecklist and
Documentation/development-process/4.Coding wants to be updated.
> I wonder whether it worked at all, because EXTRA_CFLAGS is
> reset by scripts/Makefile.build.
It did indeed work, but only because I passed the setting on the make
command line and not via the environment. I think one needs an override
directive to actually override the settings from the command line:
$ cat Makefile
VAR1 := a1
VAR2 := a2
override VAR3 := a3
override VAR4 := a4
all:
@echo $(VAR1) $(VAR2) $(VAR3) $(VAR4)
$ VAR1=b1 VAR3=b3 make VAR2=b2 VAR4=b4 all
a1 b2 a3 a4