[LLVMdev] Canonical compilers for building LLVM?

[David Blaikie]

On Fri, Jun 8, 2012 at 2:13 AM, Patrik Hägglund H
<patrik.h.hagglund at ericsson.com> wrote:
> Compiling LLVM with gcc, 4.3 and upwards, seems to give compile warnings. Is
> there any canonical gcc version that should be used (for building trunk)?
>
> From http://llvm.org/docs/HowToReleaseLLVM.html#release-build:
>
>   The builds of llvm, clang, and dragonegg must be free of errors and
> warnings in Debug, Release+Asserts, and Release builds.

I believe this hasn't been true for a while, notably there are several
instances of GCC's -Wmaybe-uninitialized warning that we just don't
fix (I could argue that they are legitimate bugs/represent UB at least
in a few cases & I've fixed a few real bugs it's found, but not
everyone agrees these are worth addressing). More importantly our bots
don't build with -Werror, so the build doesn't stay warning-clean
except by the work of developers - & most of us self-host, building
LLVM & Clang with a recent build of Clang (some of us do this with
-Werror, so the whole build is usually fairly 'clang -Werror' clean)

>   The table below specifies which compilers are used for each Arch/OS
> combination when qualifying the build of llvm, clang, and dragonegg.
>   [...]
>   x86-64        Linux   gcc 4.2.X, gcc 4.3.X
>
> This seems not to be true for the 3.1 release. I get ~10 warnings building
> llvm+clang, Release+Asserts using the gcc-4.3.4 version provided by SLED11.1
> on x86-64.
>
> /Patrik Hägglund
>
>
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