[patch] Fix x86_64 toolchain

[xyzzy]

The x86_64 toolchain currently fails to build.

The first build failure appears to be a ​problem with GCC's build system: it defaults to having multilib enabled, but if it is explicitly enabled with --enable-multilib as Haiku's build script does, the build fails. The patch to Haiku trunk removes --enable-multilib for the x86_64 target, I'm not sure if this issue affects the other targets that specify --enable-multilib.

A second build failure occurs due to the use of the TARGET_64BIT definition in preprocessor conditionals in the haiku64.h configuration file for GCC, as it is no longer a compile-time constant. The patch to buildtools fixes this, and also includes some other changes I made to the x86_64 target definition to be more correct.

[bonefish]

Alex, thanks for the patch. Although a few Haiku developers have meddled with gcc, I believe none of us is anything close to an expert. So reviewing the patch is not really trivial. Would you mind walking us through the changes? Just a short sentence for each, explaining what changed why.

Please note: I'm rather busy with real life ATM, so, unless someone else takes action, don't hold your breath for anything to happen very soon.

[xyzzy]

I don't claim to be an expert in GCC either ;) Basically what I did was changed it so that it matches the existing i386 Haiku target when generating 32-bit code, and changed some things to match x86-64.h for 64-bit code.

I'll go through each change in the buildtools patch:

• First one just changes TARGET_64BIT to TARGET_64BIT_DEFAULT, as I said TARGET_64BIT is not a compile-time constant.
• Second one just changes the comment to say that DEFAULT_PCC_STRUCT_RETURN is necessary: it is currently set on the Haiku i386 target, the ABI specifies that structs and unions must be returned in memory. When compiling 64-bit code, GCC just ignores this definition.
• Third one just changes the builtin definitions to not treat TARGET_64BIT as a constant. Also removes the definition of __x86_64__, this is set in GCC's i386-c.c.
• Fourth one changes LINK_SPEC not to be set using TARGET_64BIT. I've also removed -z max-page-size as I don't believe it should be necessary: the default page size is 2MB but this won't result in large binaries, it just changes the alignment of the sections and would make it easier to map binaries using large pages in the future.
• The next changes change it to match x86-64.h to handle some x86_64 ABI stuff.
• Finally, the last change just removes TARGET_64BIT around the debugging definitions. These are all set for the i386 target anyway so there's no need for a conditional round them.

[bonefish]

Thanks for the explanations. Please redo the patches with git format-patch so you'll get credited correctly. Your previous explanations are a good base for the commit message. :-)

[xyzzy]

Patch to build cross tools script for x86_64

[bonefish]

The buildtools patch doesn't apply. Please rebase it.

[xyzzy]

Patch to build tools for x86_64

[xyzzy]

Sorry, didn't think there would have been any changes to the x86_64 target files so didn't pull before creating the patch. Uploaded a new one.

[korli]

About haiku-x86_64-cross-tools.patch, I know gcc build has a problem with building zlib as part of a cross compiler for arm because of multilib. A workaround is to use the system zlib, which I think is acceptable, even on Haiku.

[xyzzy]

That's the same issue as I was getting for x86_64. I don't know whether multilib is on by default for ARM if you don't enable it explicitly (it is for x86_64). If you'd prefer to change it to use the system zlib instead then I think that would work for x86_64.

[bonefish]

Thanks, applied both patches as btrev43030 and hrev43954 respectively.

No clue about the ARM build. I don't even know what multilib would target in this case.