[LLVMdev] DragonEgg 3.0 with GCC 4.7

[Duncan Sands]

Hi Eric,

> I've been trying to package DragonEgg for Fedora Linux.  Fedora 16 has
> LLVM 2.9 and GCC 4.6, but not the necessary GCC patches.  If I build
> LLVM 3.0 on Fedora 16, then I can build DragonEgg 3.0, and it works
> fine.  However, I can't submit that to the repository.
>
> On the other hand, Fedora 17, which just entered Beta, has LLVM 3.0 and
> GCC 4.7.  I wasn't able to build DragonEgg 3.0 with GCC 4.7 due to an
> error compiling Backend.cpp, but yesterday I saw that commit #152558
> fixes this.

it was a warning not an error, but perhaps you build with -Werror?

   However, now when I try to build DragonEgg, I get a lot of
> other errors.

I've started porting dragonegg to gcc-4.7 (I fixed a few things this weekend
already).  The same-body alias implementation changed substantially it seems,
and I also see a lot of compile failures in Convert.cpp related to
synchronization primitives, probably coming from the GCC changes made to
support C++-11 atomics.  These two will require time, thought and care to
update right.  ABIHack.inc is also failing to compile, but this looks
to be a mild problem.

That said, getting it compiling is not the same as having it work well, or even
work at all.  For example, if gcc-4.7 is bootstrapped then it compiles itself
using the first-stage C++ compiler which means that all names are mangled, while
if gcc-4.7 is not bootstrapped then names are not mangled because it is compiled
as C.  Currently dragonegg expects names to not be mangled, but it will somehow
have to detect gcc's with mangled names otherwise it will fail miserably.

Ciao, Duncan.

> On the one hand, I don't expect there to be any official support for
> DragonEgg 3.0 with GCC 4.7.  On the other hand, it would be nice to get
> DragonEgg into Fedora 17 rather than having to wait another six months
> for LLVM 3.1 to land in Fedora 18.  Would anyone care to look at the
> build problems I'm seeing?  Perhaps these problems were already fixed in
> other commits in the repository.
>
> Some of the errors I'm getting are:
>
> /builddir/build/BUILD/dragonegg-3.0.src/src/Trees.cpp: In function 'uint64_t getFieldOffsetInBits(tree)':
> /builddir/build/BUILD/dragonegg-3.0.src/src/Trees.cpp:191:56: error: 'BITS_PER_UNIT' was not declared in this scope
>
> /builddir/build/BUILD/dragonegg-3.0.src/src/DefaultABI.cpp: In member function 'void DefaultABI::HandleArgument(tree, std::vector<llvm::Type*, std::allocator<llvm::Type*>   >&, llvm::Attributes*)':
> /builddir/build/BUILD/dragonegg-3.0.src/src/DefaultABI.cpp:223:14: error: 'TARGET_64BIT' was not declared in this scope
> In file included from /usr/lib/gcc/x86_64-redhat-linux/4.7.0/plugin/include/tm_p.h:5:0,
>                    from /builddir/build/BUILD/dragonegg-3.0.src/src/Constants.cpp:52:
> /usr/lib/gcc/x86_64-redhat-linux/4.7.0/plugin/include/tm-preds.h:191:13: error: use of enum 'reg_class' without previous declaration
> /usr/lib/gcc/x86_64-redhat-linux/4.7.0/plugin/include/tm-preds.h:191:68: error: invalid type in declaration before ';' token
> /builddir/build/BUILD/dragonegg-3.0.src/src/Constants.cpp: In member function '{anonymous}::BitSlice {anonymous}::BitSlice::ExtendRange(SignedRange, llvm::TargetFolder&) const':
> /builddir/build/BUILD/dragonegg-3.0.src/src/Constants.cpp:188:7: error: 'BYTES_BIG_ENDIAN' was not declared in this scope
> /builddir/build/BUILD/dragonegg-3.0.src/src/Constants.cpp: In member function '{anonymous}::BitSlice {anonymous}::BitSlice::ReduceRange(SignedRange, llvm::TargetFolder&) const':
>
>
> The full build log is at:
>
> http://koji.fedoraproject.org/koji/getfile?taskID=3925063&name=build.log
>
> Once i can get DragonEgg into Fedora, I'm hoping to convince the package
> maintainers for GCC in Red Hat Enterprise Linux 6 to include the patch
> to GCC 4.4 necessary to build DragonEgg 2.8, since I expect it will be a
> long time (years!) before LLVM 3.x shows up in RHEL7.
>
> Thanks!
> Eric
>
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