With clang if the main file is <stdin>, the first non-main-file
dependency is not listed in the -MP output. Although it was fixed
on clang-16 [1], this change adds portability for older version.
[1] https://github.com/llvm/llvm-project/commit/
ff9576f74514b836e1ba0268409a2ecb919d7118
Reviewed-by: Fangrui Song <maskray@google.com>
# copy of those headers in Makerules.
if test -n "$CXX"; then
find_cxx_header () {
- echo "#include <$1>" | $CXX -M -MP -x c++ - 2>/dev/null \
- | sed -n "\,$1:,{s/:\$//;p}"
+ echo "#include <$1>" | $CXX -H -fsyntax-only -x c++ - 2>&1 \
+ | $AWK '$1 == "."{print $2}'
}
CXX_CSTDLIB_HEADER="$(find_cxx_header cstdlib)"
CXX_CMATH_HEADER="$(find_cxx_header cmath)"
# copy of those headers in Makerules.
if test -n "$CXX"; then
find_cxx_header () {
- echo "#include <$1>" | $CXX -M -MP -x c++ - 2>/dev/null \
- | sed -n "\,$1:,{s/:\$//;p}"
+ echo "#include <$1>" | $CXX -H -fsyntax-only -x c++ - 2>&1 \
+ | $AWK '$1 == "."{print $2}'
}
CXX_CSTDLIB_HEADER="$(find_cxx_header cstdlib)"
CXX_CMATH_HEADER="$(find_cxx_header cmath)"