3GB kernel binary!

[Colonel Kernel]

Wow, something went really wrong here. For a long time I've been running two parallel builds of my kernel -- one that passes -D NDEBUG to gcc (my "free" build) and one without (my "checked" build). I added -O3 to the compiler settings for my free build, and suddenly my kernel binary grows from 23KB to 3GB!

I'm guessing there is something subtle that I don't understand about my linker script, since my kernel is linked to run in the higher half. Here it is:

Code: Select all

ENTRY (StartPrecursor)

OUTPUT_FORMAT(binary)
SECTIONS
{
    . = 0xC0100000;

    .text :
    {
        *(.text)
        *(.rodata)
    }

    .data ALIGN (0x1000) :
    {
        *(.data)
    }

    .bss :
    {
        _sbss = .;
        *(COMMON)
        *(.bss)
        _ebss = .;
    }
}

Are there any magical sections I'm not aware of that would only show up when compiling with -O3 (or any of the -O's, they all do the same thing)? BTW, I'm using a gcc cross-compiler (built from gcc 3.4.1 sources according to the instructions on the OS FAQ).

[pradeep]

Well i really don't know the answer but the same question was posted long back and i think it was answered by Pype.Clicker better he could give you the answer

[Colonel Kernel]

Thanks for mentioning Pype's name -- that finally got me some results in the forum's search function.

Apparently, using -O3 was causing some of the string constants to go in sections named .rodata.strx.y. This fixed it:

Code: Select all

ENTRY (StartPrecursor)

OUTPUT_FORMAT(binary)
SECTIONS
{
    . = 0xC0100000;

    .text :
    {
        *(.text)
        *(.rodata*)               /* <--- aha! */
    }

    .data ALIGN (0x1000) :
    {
        *(.data)
    }

    .bss :
    {
        _sbss = .;
        *(COMMON)
        *(.bss)
        _ebss = .;
    }
}

[Pype.Clicker]

;D ROFL. Just invoke my name and your kernel will automagically debug
For I am the mighty wizard of OS. How wizzy your OS is, the wizard has a wizzer for your for nothing is too wizzy for the wize wizard of OS. ;D

(seems i'm in a hilarous-like-BI day )

[DruG5t0r3]

Follow the binary brick wall ;D

[0Scoder]

lol, could be an advert for broadband: Follow the megabit road could be a nice slogan

[Pype.Clicker]

@oscoder: i suppose "follow the white megrabit" will hit broader audience
@drugstore: actually, it's "The Road of Yellow Bits".