OSDev.org

Combuster wrote:Can't reproduce error. I took the build script, created the missing directories, replaced the harcoded paths to gcc and ld (not good), and replaced qemu with qemu-system-i386. Kernel got started without error but wasn't particularly interesting.

In other words: Go fix your tools.

I used the following tool from my system. Make sure your versions are at least that.
Binutils 2.18
GCC 4.1.2
mkisofs 3.00
qemu 1.0-r3

requimrar wrote:I changed things around and it still works. Bad voodoo. Well either way it's solved, although we didn't get the cause, which I would like to.

Blacklight wrote:

requimrar wrote:I changed things around and it still works. Bad voodoo. Well either way it's solved, although we didn't get the cause, which I would like to.

That doesn't mean you've fixed it. That just means that something happened to stop the bug from occurring. It could resurface at any time down the road, and when it does, you won't have any idea where it is.

I suggest you un-"fix" it, build yourself a brand new set of tools (because, as Combuster says, they're likely broken), and try again. That way, if it fixes it, you've learned a valuable lesson.

I had to change some things

build yourself a brand new set of tools (because, as Combuster says, they're likely broken).

piranha wrote:

I had to change some things

build yourself a brand new set of tools (because, as Combuster says, they're likely broken).

What exactly did you change?

-JL

requimrar wrote:The wiki says not to use the llvm compiler, but all the gcc-4.2 compilers were just aliases to the llvm compiler.

GCC Cross-Compiler wrote:MacOS users, beware

The makefiles of binutils and GCC use the `$(CC)` variable to invoke the compiler. On MacOS, this resolves to `gcc` by default, which is actually not the "real thing", but `llvm-gcc`. That wouldn't be so bad, but `llvm-gcc` is not able to compile the GCC sources into a functional binary. (Bugs have been reported, but that doesn't help you here and now.)

MacOS does have a "real" GCC installed, too. You just have to tell `make` to use it instead of `llvm-gcc`:

Code: Select all

# This is only necessary for MacOS users.
export CC=/usr/bin/gcc-4.2
export CXX=/usr/bin/g++-4.2
export CPP=/usr/bin/cpp-4.2
export LD=/usr/bin/gcc-4.2

Solar wrote:

requimrar wrote:The wiki says not to use the llvm compiler, but all the gcc-4.2 compilers were just aliases to the llvm compiler.

Please be precise: Are you saying that the following part of the Wiki does not indeed work on a Mac?

GCC Cross-Compiler wrote:MacOS users, beware

The makefiles of binutils and GCC use the `$(CC)` variable to invoke the compiler. On MacOS, this resolves to `gcc` by default, which is actually not the "real thing", but `llvm-gcc`. That wouldn't be so bad, but `llvm-gcc` is not able to compile the GCC sources into a functional binary. (Bugs have been reported, but that doesn't help you here and now.)

MacOS does have a "real" GCC installed, too. You just have to tell `make` to use it instead of `llvm-gcc`:

Code: Select all

# This is only necessary for MacOS users.
export CC=/usr/bin/gcc-4.2
export CXX=/usr/bin/g++-4.2
export CPP=/usr/bin/cpp-4.2
export LD=/usr/bin/gcc-4.2

requimrar wrote:I used the llvm compiler in all 4 export's and yes, it does compile.

GCC Cross-Compiler wrote:[...] `llvm-gcc` is not able to compile the GCC sources into a functional binary. (Bugs have been reported, but that doesn't help you here and now.)

Solar wrote:

requimrar wrote:I used the llvm compiler in all 4 export's and yes, it does compile.

That was never in doubt. The tutorial says:

GCC Cross-Compiler wrote:[...] `llvm-gcc` is not able to compile the GCC sources into a functional binary. (Bugs have been reported, but that doesn't help you here and now.)

So either you have a non-functional GCC binary (i.e., compiling it worked allright, but the GCC binary you got won't work correctly, if at all). Or llvm resolved the bugs. In the former case, you are working from flawed assumptions, in the latter case our Wiki needs updating. Either way, another round of testing your assumptions is in order.

requimrar wrote:Just in case you want to replicate my setup...

berkus wrote:

requimrar wrote:I used the llvm compiler in all 4 export's and yes, it does compile.

You might be lying about gcc-4.2 being llvm-gcc though:

Code: Select all

$ /usr/bin/gcc-4.2 --version
i686-apple-darwin11-gcc-4.2.1 (GCC) 4.2.1 (Apple Inc. build 5666) (dot 3)

What's on yours?

/usr/llvm-gcc-4.2/bin/

Thread model: posix
gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.9.00)

requimrar wrote:If someone has the time... and is using OSX (I think berkus?)

I don't think that it's the tools that are causing it, but just to make sure, can someone else test them for me? I only have one machine. :/

Blacklight wrote: Fire up a VM running Ubuntu and try building on there. If it works, it's your tools. If it doesn't, it's your code.

Ten bucks says it's the tools.

Why do we need one?
Creating a dedicated (cross-)compiler for your OS development work can save you many headaches. If
...
... your bootloader stubbornly insists that it can't read your kernel binary...

TARGET=i586-elf

TARGET=x86_64-elf

requimrar wrote:You can't actually do the latter on a 32-bit system, can you?

I don't think that it's the tools that are causing it, but just to make sure, can someone else test them for me? I only have one machine. :/