[Bug preprocessor/54600] New: Header file missing from dependency file.

[mr.duncan.moore at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54600

             Bug #: 54600
           Summary: Header file missing from dependency file.
    Classification: Unclassified
           Product: gcc
           Version: 4.5.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: preprocessor
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: mr.duncan.mo...@gmail.com


In this simplified example, the local unistd.h is absent from the dependency
file.

% gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-pc-cygwin/4.5.3/lto-wrapper.exe
Target: i686-pc-cygwin
Configured with:
/gnu/gcc/releases/respins/4.5.3-3/gcc4-4.5.3-3/src/gcc-4.5.3/configure
--srcdir=/gnu/gcc/releases/respins/4.5.3-3/gcc4-4.5.3-3/src/gcc-4.5.3
--prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin
--libexecdir=/usr/lib --datadir=/usr/share --localstatedir=/var
--sysconfdir=/etc --datarootdir=/usr/share --docdir=/usr/share/doc/gcc4 -C
--datadir=/usr/share --infodir=/usr/share/info --mandir=/usr/share/man -v
--with-gmp=/usr --with-mpfr=/usr --enable-bootstrap
--enable-version-specific-runtime-libs --libexecdir=/usr/lib --enable-static
--enable-shared --enable-shared-libgcc --disable-__cxa_atexit --with-gnu-ld
--with-gnu-as --with-dwarf2 --disable-sjlj-exceptions
--enable-languages=ada,c,c++,fortran,java,lto,objc,obj-c++ --enable-graphite
--enable-lto --enable-java-awt=gtk --disable-symvers --enable-libjava
--program-suffix=-4 --enable-libgomp --enable-libssp --enable-libada
--enable-threads=posix --with-arch=i686 --with-tune=generic
--enable-libgcj-sublibs CC=gcc-4 CXX=g++-4 CC_FOR_TARGET=gcc-4
CXX_FOR_TARGET=g++-4 GNATMAKE_FOR_TARGET=gnatmake GNATBIND_FOR_TARGET=gnatbind
--with-ecj-jar=/usr/share/java/ecj.jar
Thread model: posix
gcc version 4.5.3 (GCC)

% cat xyz.c
#include <fcntl.h>

% cat fcntl.h
#pragma GCC system_header
#include <unistd.h>

% cat unistd.h
dummy error line

% gcc -E -MMD -I. -o xyz.i xyz.c

The local unistd.h is included:

% cat xyz.i
# 1 "xyz.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "xyz.c"
# 1 "./fcntl.h" 1

# 2 "./fcntl.h" 3
# 1 "./unistd.h" 1 3
dummy error line
# 2 "./fcntl.h" 2 3
# 1 "xyz.c" 2

, but not put in the dependency file:

% cat xyz.d
xyz.o: xyz.c fcntl.h

I would expect:

% cat xyz.d
xyz.o: xyz.c fcntl.h unistd.h

Note that replacing -MMD by -MD gives the expected dependency file.