@@ -14,13 +14,14 @@ fi
TMPC="${TMPDIR1}/qemu-conf-${RANDOM}-$$-${RANDOM}.c"
TMPB="qemu-conf-${RANDOM}-$$-${RANDOM}"
TMPO="${TMPDIR1}/${TMPB}.o"
+TMPCXX="${TMPDIR1}/${TMPB}.cxx"
TMPL="${TMPDIR1}/${TMPB}.lo"
TMPA="${TMPDIR1}/lib${TMPB}.la"
TMPE="${TMPDIR1}/qemu-conf-${RANDOM}-$$-${RANDOM}.exe"
# NB: do not call "exit" in the trap handler; this is buggy with some shells;
# see <1285349658-3122-1-git-send-email-loic.minier@linaro.org>
-trap "rm -f $TMPC $TMPO $TMPE" EXIT INT QUIT TERM
+trap "rm -f $TMPC $TMPO $TMPCXX $TMPE" EXIT INT QUIT TERM
rm -f config.log
# Print a helpful header at the top of config.log
@@ -54,10 +55,13 @@ error_exit() {
exit 1
}
-do_cc() {
- # Run the compiler, capturing its output to the log.
- echo $cc "$@" >> config.log
- $cc "$@" >> config.log 2>&1 || return $?
+do_compiler() {
+ # Run the compiler, capturing its output to the log. First argument
+ # is compiler binary to execute.
+ local compiler="$1"
+ shift
+ echo $compiler "$@" >> config.log
+ $compiler "$@" >> config.log 2>&1 || return $?
# Test passed. If this is an --enable-werror build, rerun
# the test with -Werror and bail out if it fails. This
# makes warning-generating-errors in configure test code
@@ -71,14 +75,39 @@ do_cc() {
return 0
;;
esac
- echo $cc -Werror "$@" >> config.log
- $cc -Werror "$@" >> config.log 2>&1 && return $?
+ echo $compiler -Werror "$@" >> config.log
+ $compiler -Werror "$@" >> config.log 2>&1 && return $?
error_exit "configure test passed without -Werror but failed with -Werror." \
"This is probably a bug in the configure script. The failing command" \
"will be at the bottom of config.log." \
"You can run configure with --disable-werror to bypass this check."
}
+do_cc() {
+ do_compiler "$cc" "$@"
+}
+
+do_cxx() {
+ do_compiler "$cxx" "$@"
+}
+
+update_cxxflags() {
+ # Set QEMU_CXXFLAGS from QEMU_CFLAGS by filtering out those
+ # options which some versions of GCC's C++ compiler complain about
+ # because they only make sense for C programs.
+ QEMU_CXXFLAGS=
+ for arg in $QEMU_CFLAGS; do
+ case $arg in
+ -Wstrict-prototypes|-Wmissing-prototypes|-Wnested-externs|\
+ -Wold-style-declaration|-Wold-style-definition|-Wredundant-decls)
+ ;;
+ *)
+ QEMU_CXXFLAGS=${QEMU_CXXFLAGS:+$QEMU_CXXFLAGS }$arg
+ ;;
+ esac
+ done
+}
+
compile_object() {
do_cc $QEMU_CFLAGS -c -o $TMPO $TMPC
}
@@ -1320,6 +1349,19 @@ if test "$ARCH" = "unknown"; then
fi
fi
+# Consult white-list to determine whether to enable werror
+# by default. Only enable by default for git builds
+z_version=`cut -f3 -d. $source_path/VERSION`
+
+if test -z "$werror" ; then
+ if test -d "$source_path/.git" -a \
+ "$linux" = "yes" ; then
+ werror="yes"
+ else
+ werror="no"
+ fi
+fi
+
# check that the C compiler works.
cat > $TMPC <<EOF
int main(void) { return 0; }
@@ -1340,14 +1382,16 @@ EOF
compile_object
- cat > $TMPC <<EOF
+ cat > $TMPCXX <<EOF
extern "C" {
int c_function(void);
}
int c_function(void) { return 42; }
EOF
- if (cc=$cxx do_cc $QEMU_CFLAGS -o $TMPE $TMPC $TMPO $LDFLAGS); then
+ update_cxxflags
+
+ if do_cxx $QEMU_CXXFLAGS -o $TMPE $TMPCXX $TMPO $LDFLAGS; then
# C++ compiler $cxx works ok with C compiler $cc
:
else
@@ -1360,19 +1404,6 @@ else
cxx=
fi
-# Consult white-list to determine whether to enable werror
-# by default. Only enable by default for git builds
-z_version=`cut -f3 -d. $source_path/VERSION`
-
-if test -z "$werror" ; then
- if test -d "$source_path/.git" -a \
- "$linux" = "yes" ; then
- werror="yes"
- else
- werror="no"
- fi
-fi
-
gcc_flags="-Wold-style-declaration -Wold-style-definition -Wtype-limits"
gcc_flags="-Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers $gcc_flags"
gcc_flags="-Wmissing-include-dirs -Wempty-body -Wnested-externs $gcc_flags"
gcc's C++ compiler complains about being passed some -W options which make sense for C but not for C++. This means we mustn't try a C++ compile with QEMU_CFLAGS, but only with a filtered version that removes the offending options. This filtering was already being done for uses of C++ in the build itself, but was omitted for the "does C++ work?" configure test. This only showed up when doing builds which explicitly enabled -Werror with --enable-werror, because the "do the compilers work" tests were mistakenly placed above the "default werror based on whether compiling from git" code. Another error in this category is that clang warns if you ask it to compile C++ code from a file named "foo.c". Further, because we were running do_cc in a subshell in the condition part of an "if", the error_exit inside do_compiler wouldn't terminate configure and we would plunge on regardless. Fix this complex of errors: 1. Move the default-werror code up so that there are no invocations of compile_object and friends between it and the point where we set $werror explicitly based on the --enable-werror command line option. 2. Provide a mechanism for filtering QEMU_CFLAGS to create QEMU_CXXFLAGS, and use it for the test we run here. 3. Provide a do_cxx function to run a test with the C++ compiler rather than doing cute tricks with subshells and do_cc. 4. Use a new temporary file TMPCXX for the C++ program fragment. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- Changes v1->v2: item 4, use TMPCXX for the C++ source so that clang doesn't warn (and trigger build failure if -Werror) configure | 75 ++++++++++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 53 insertions(+), 22 deletions(-)