OS-Specific Toolchain not listening to config values

[zhiayang]

Hello. After what seems like an eternity (4 years actually, might as well be), I can finally compile and run a simple program:

Code: Select all

int main()
{
        return 0;
}

without too much trouble on my part. So the other day I was adding features to my libc, when I was getting a bunch of errors.
Turns out gcc (stupidly) adds 'extern "C"' around headers in sysroot/usr/include, even if they're .hpp headers.

so sortie tells me about NO_IMPLICIT_EXTERN_C that I have to define in gcc/config/myos.h, and so I define it and recompile my toolchain. No dice. So between adding "extern "C++" " around my C++ headers and just not putting them in the sysroot, i chose the latter.

This morning I managed to get the above program (return 0) to compile. Except the executable is about 2.3 mb large. Remembering my early experiences, I again realised that LD wasn't heeding the script in ld/emulparams/elf64myos.sh. I specifically set that one parameter for max page size to 0x1000.

So, I both need a linker script (LD doesn't listen to the config about where to put the .text section) and a -Wl,-z,-max-page-size=0x1000 option, so it's definitely not as easy as 'g++ file.c -o file.x'

What's the issue? I followed the OS Specific Toolchain article almost to the letter, except for a couple of differences:
1. I used --with-sysroot=sysroot when configuring (according to sortie), and placed a couple of important header files in sysroot/usr/include.
2. I didn't build my libc in that step, but I build it together with my kernel, and it goes in sysroot/usr/lib.
3. Therefore, I copied the crt*.s files from Creating a C Library, and also put them in sysroot/usr/lib.

Incidentally, LD also doesn't seem to find libraries in 'sysroot/usr/lib' without an explicit '-L' parameter, but GCC can.

Any help?

Relevant files:
binutils-2.24/ld/emulparams/elf64myos.h

Code: Select all

. ${srcdir}/emulparams/plt_unwind.sh
SCRIPT_NAME=elf
ELFSIZE=64
OUTPUT_FORMAT="elf64-x86-64"
NO_REL_RELOCS=yes
MAXPAGESIZE=0x1000
COMMONPAGESIZE=0x1000
TEXT_START_ADDR=0x40000000
LARGE_DATA_ADDR=0x80020000000
ARCH="i386:x86-64"
MACHINE=
TEMPLATE_NAME=elf32
GENERATE_SHLIB_SCRIPT=yes
GENERATE_PIE_SCRIPT=yes
LARGE_SECTIONS=yes
NO_SMALL_DATA=yes
IREL_IN_PLT=

gcc-4.9.1/gcc/config/myos.h

Code: Select all

#undef TARGET_EXECUTABLE_SUFFIX
#define TARGET_EXECUTABLE_SUFFIX ".oex"

#error "LOLWHAT"

#undef TARGET_ORIONX
#define TARGET_ORIONX 1

#undef NO_IMPLICIT_EXTERN_C
#define NO_IMPLICIT_EXTERN_C 1

#define TARGET_OS_CPP_BUILTINS()		\
  do						\
    {						\
      builtin_define ("__ORIONX__");		\
      builtin_assert ("__unix__");		\
      builtin_assert ("system=orionx");		\
      builtin_assert ("system=unix");		\
    }						\
  while (0)

^ Note the #error "LOLWHAT", which sortie told me to put -- good call on his part, no error during building means gcc isn't using that file at all.

Thanks.

[zhiayang]

Solved now, I was building for x86_64-myos-elf instead of just x86_64-myos.

Again, solved with the help of sortie on #osdev.