对“__GLOBAL_OFFSET_TABLE”的未定义引用

Question

I have added -fno-pie in the CFLAGS, but it still shows this error:

ld -melf_i386 -T linker.ld -o kernel.bin start.o kernel.o console.o utils.o
kernel.o: In function `_main':
kernel.C:(.text+0x16): undefined reference to `__GLOBAL_OFFSET_TABLE_'
makefile:30: recipe for target 'kernel.bin' failed
make: *** [kernel.bin] Error 1

The make file is shown below:

GCC_OPTIONS = -m32 -fno-pie -nostdlib -fno-builtin -nostartfiles -nodefaultlibs -fno-exceptions -fno-rtti -fno-stack-protector -fleading-underscore -fno-asynchronous-unwind-tables

all: kernel.bin

clean:
    rm -f *.o *.bin

# ==== KERNEL ENTRY POINT ====

start.o: start.asm
    nasm -f aout -o start.o start.asm

# ==== UTILITIES ====

utils.o: utils.H utils.C
    gcc $(GCC_OPTIONS) -c -o utils.o utils.C

# ==== DEVICES ====

console.o: console.H console.C
    gcc $(GCC_OPTIONS) -c -o console.o console.C

# ==== KERNEL MAIN FILE ====

kernel.o: kernel.C
    gcc $(GCC_OPTIONS) -c -o kernel.o kernel.C


kernel.bin: start.o kernel.o console.o utils.o linker.ld
    ld -melf_i386 -T linker.ld -o kernel.bin start.o kernel.o console.o utils.o

May I ask help for this question?

Thank you in advance.

Answer 1

First thing that striked me was "why you're using .C (capitalized) extension for .c file, it's reserved for C++?". So I made a test:

# with `-fno-rtti'
$ export CFLAGS1="-m32 -fno-pie -nostdlib -fno-builtin -nostartfiles -nodefaultlibs -fno-exceptions -fno-rtti -fno-stack-protector -fleading-underscore -fno-asynchronous-unwind-tables"
# without `-fno-rtti'
$ export CFLAGS2="-m32 -fno-pie -nostdlib -fno-builtin -nostartfiles -nodefaultlibs -fno-exceptions  -fno-stack-protector -fleading-underscore -fno-asynchronous-unwind-tables"
$ mv kernel.C kernel1.C
$ cp kernel.C kernel2.c
$ gcc $CFLAGS1 -c -o kernel1.C.o kernel1.C

$ gcc $CFLAGS1 -c -o kernel2.c.o kernel2.c
cc1: warning: command line option '-fno-rtti' is valid for C++/ObjC++ but not for C
$ gcc $CFLAGS2 -c -o kernel2.c.o kernel2.c

So I bet if you decapitalize your extensions form .C into .c and .H into .h you'll get better results. GCC is fussy in this regard. If you want C code use gcc and .c extension, if you want C++ use g++ and .C or .cc or .cpp or .cxx .

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Also I think you should use gcc instead of ld as link command. Ld is usually "stupid" and gcc knows better.

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PS. Let me know which one is/is not right. If wrong I will remove answer to not confuse audience.