CVS commit: src/usr.bin/make

["Roland Illig" <rillig%netbsd.org@localhost>]

Module Name:    src
Committed By:   rillig
Date:           Mon Dec 13 05:25:04 UTC 2021

Modified Files:
        src/usr.bin/make: main.c make.h parse.c str.c str.h

Log Message:
make: fix memory leak for filenames in .for loops (since 2013-06-18)

Previously, each time a .for directive pushed its buffer on the input
file stack, the current filename was duplicated.  This was a waste of
memory.

The name of a file is typically only used while it is read in.  There is
one situation when the filename is needed for longer, which is when a
target is defined.

Since .for loops are implemented as a special form of included files,
each .for loop duplicated the current filename as well.

$ cat << EOF > for.mk
.for i in 1 2 3 4 5 6 7 8 9 0
.for i in 1 2 3 4 5 6 7 8 9 0
.for i in 1 2 3 4 5 6 7 8 9 0
.for i in 1 2 3 4 5 6 7 8 9 0
.for i in 1 2 3 4 5 6 7 8 9 0
.for i in 1 2 3 4 5 6 7 8 9 0
.for i in 1 2 3 4 5 6 7 8 9 0
.endfor
.endfor
.endfor
.endfor
.endfor
.endfor
.endfor

all:
        @ps -o rsz -p ${.MAKE.PID}
EOF

$ make-2021.12.13.03.55.16 -r -f for.mk
  RSZ
10720

$ ./make -r -f for.mk
 RSZ
1716

The difference is 8 MB, which amounts to 1 million .for loops.


To generate a diff of this commit:
cvs rdiff -u -r1.541 -r1.542 src/usr.bin/make/main.c
cvs rdiff -u -r1.270 -r1.271 src/usr.bin/make/make.h
cvs rdiff -u -r1.575 -r1.576 src/usr.bin/make/parse.c
cvs rdiff -u -r1.86 -r1.87 src/usr.bin/make/str.c
cvs rdiff -u -r1.13 -r1.14 src/usr.bin/make/str.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.