saveourtool/kompiledb

Recognize `-nostdinc`, `-nostdinc++` & friends for Clang and GCC

0x6675636b796f75676974687562 opened this issue · 0 comments

0x6675636b796f75676974687562 commented

There're 3 categories of standard headers:

  1. The standard C library
  2. The standard C++ library
  3. Compiler-specific built-in headers

The -no...inc switches have the following meaning in Clang and GCC:

Switch Included headers, C (-xc) Included headers, C++ (-xc++)
-nostdinc Empty list C++ (Clang) or empty list (GCC)
-nostdinc++ C, compiler built-in C, compiler built-in
-nostdlibinc Compiler built-in only Compiler built-in only
-nobuiltininc C C, C++

The one-liner to find out the built-in include directories:

${CC} ${CFLAGS} -v -E -o- - </dev/null 2>&1 >/dev/null | grep -F '#include <...> search starts here:' -A 99 | grep '^\s' | xargs -rn1 realpath | sort -u

CFLAGS must specify the language (-xc or -xc++) and, optionally, may include -nostdinc and/or nostdinc++.

GCC

C (-xc)

Default (no directories excluded)

Standard C library and compiler built-in includes:

/usr/include
/usr/include/x86_64-linux-gnu
/usr/lib/gcc/x86_64-linux-gnu/10/include
/usr/local/include

-nostdinc

Empty list.

-nostdinc++

Standard C library and compiler built-in includes:

/usr/include
/usr/include/x86_64-linux-gnu
/usr/lib/gcc/x86_64-linux-gnu/10/include
/usr/local/include

C (-xc++)

Default (no directories excluded)

Standard C and C++ library and compiler built-in includes:

/usr/include
/usr/include/c++/10
/usr/include/c++/10/backward
/usr/include/x86_64-linux-gnu
/usr/include/x86_64-linux-gnu/c++/10
/usr/lib/gcc/x86_64-linux-gnu/10/include
/usr/local/include

-nostdinc

Empty list.

-nostdinc++

Standard C library and compiler built-in includes:

/usr/include
/usr/include/x86_64-linux-gnu
/usr/lib/gcc/x86_64-linux-gnu/10/include
/usr/local/include

Clang

C (-xc)

Default (no directories excluded)

Standard C library and compiler built-in includes:

/usr/include
/usr/include/x86_64-linux-gnu
/usr/lib/llvm-11/lib/clang/11.0.1/include
/usr/local/include

-nostdinc

Empty list.

-nostdinc++

Standard C library and compiler built-in includes:

/usr/include
/usr/include/x86_64-linux-gnu
/usr/lib/llvm-11/lib/clang/11.0.1/include
/usr/local/include

-nostdlibinc

Compiler built-in includes:

/usr/lib/llvm-11/lib/clang/11.0.1/include

-nobuiltininc

Standard C library includes:

/usr/include
/usr/include/x86_64-linux-gnu
/usr/local/include

C (-xc++)

Default (no directories excluded)

Standard C and C++ library and compiler built-in includes:

/usr/include
/usr/include/c++/10
/usr/include/c++/10/backward
/usr/include/x86_64-linux-gnu
/usr/include/x86_64-linux-gnu/c++/10
/usr/lib/llvm-11/lib/clang/11.0.1/include
/usr/local/include

-nostdinc

Standard C++ library includes:

/usr/include/c++/10
/usr/include/c++/10/backward
/usr/include/x86_64-linux-gnu/c++/10

-nostdinc++

Standard C library and compiler built-in includes:

/usr/include
/usr/include/x86_64-linux-gnu
/usr/lib/llvm-11/lib/clang/11.0.1/include
/usr/local/include

-nostdlibinc

Compiler built-in includes:

/usr/lib/llvm-11/lib/clang/11.0.1/include

-nobuiltininc

Standard C and C++ library includes:

/usr/include
/usr/include/c++/10
/usr/include/c++/10/backward
/usr/include/x86_64-linux-gnu
/usr/include/x86_64-linux-gnu/c++/10
/usr/local/include