https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65820
Bug ID: 65820
Summary: escape backslashes in .d file
Product: gcc
Version: 4.8.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: other
Assignee: unassigned at gcc dot gnu.org
Reporter: paul_robinson at playstation dot sony.com
gcc should escape backslashes when writing a .d file, because that's
what GNU make expects.
(Yes, I know special characters in filenames are a bad idea...)
There are various scenarios, this one seems to be the easiest to
demonstrate.
$ gcc --version
gcc (Ubuntu 4.8.2-19ubuntu1) 4.8.2
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ make --version
GNU Make 3.81
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
This program built for x86_64-pc-linux-gnu
$ cat quote.c
#include "a\\b.h"
$ # BTW that's two backslashes, not one escaped backslash; C11 6.4.7.
$ touch a\\\\b.h
$ gcc -c -MMD quote.c
$ # But the .d file just copies the string literally.
$ cat quote.d
quote.o: quote.c a\\b.h
$ rm a\\\\b.h
$ # Make properly doesn't find the nonexistent file....
$ make -f quote.d quote.o
make: *** No rule to make target `a\\b.h', needed by `quote.o'. Stop.
$ # Accidentally create the wrong number of backslashes...
$ touch a\\b.h
$ # ...make will interpret a\\b.h as a\b.h, even though gcc doesn't.
$ make -f quote.d quote.o
cc -c -o quote.o quote.c
quote.c:1:18: fatal error: a\\b.h: No such file or directory
#include "a\\b.h"
^
compilation terminated.
make: *** [quote.o] Error 1
$
If I modify the .d file to escape backslashes, it works properly.
$ cat quote.d
quote.o: quote.c a\\\\b.h
$ touch a\\\\b.h
$ ls
a\\b.h quote.c quote.d
$ make -f quote.d quote.o
cc -c -o quote.o quote.c
$
