[llvm-dev] unable to compile llvm with gcc 4.7.4

[via llvm-dev]

On Wed, Oct 12, 2016 at 07:15:39PM +0100, Renato Golin wrote:
> On 12 October 2016 at 18:37,  <sylvain.bertrand at gmail.com> wrote:
> > Suggestion is not clear answer. How such a decision taken? Is there a board of
> > people which have to vote to valid the choice of minimal gcc (and clang) version
> > effective?
> 
> We don't have such process, unfortunately. :)
> 
> 
> > If gcc 4.7 (last 1-step C boostrap-able c++-ish compiler) is phased out, then,
> > to bootstrap llvm from a C compiler/runtime, gcc(4.7.4) + gcc(version>=4.8)
> > will have to be setup first.
> 
> I want to understand your constraints, as I think this is a unique
> case that I wasn't considering.

It's my custom distro. My goal is to make it boostrap-able with tinycc (or any
little C compiler alternative) as a one-man reasonable job. With the removal of
gcc 4.7 support now official, I would need to have a 3 step bootstrap, adding a
modern gcc (which is guaranted to compile with iso c++98-ish gcc 4.7.4, feature
that clang cannot guaranted anymore).

I'm targetting llvm only for its AMDGPU backend (AMD southern island GPU
architecture). Hacking the build system made me manage to compile llvm libs
with gcc 4.7.4:
	- I removed libLTO, all tools except llvm-config.
	- all tools except llvm-config.
Till mesa compiles and runs fine, I don't care about the rest of llvm.

----

BTW, the llvm build system is kind of weird. libLTO and tools are llvmbuild.txt
components, I though I could deal only with llvmbuild.txt files to disable them, but
I had to deal with CMakefile.txt files too. Expected?

-- 
Sylvain