[LLVMdev] [cfe-dev] RFC: Upcoming Build System Changes

[Óscar Fuentes]

Nico Weber <thakis at chromium.org> writes:

> On Tue, Nov 1, 2011 at 3:09 PM, David A. Greene <greened at obbligato.org> wrote:
>> Óscar Fuentes <ofv at wanadoo.es> writes:
>>
>>> Okay, we can get rid of recursive make. However, as pointed out
>>> elsewhere, removing recursive make will not make a difference on the
>>> LLVM build. What David Greene says probably is related to difference
>>> sizes among his compiler and LLVM.
>
> I doubt that's true: Chromium's empty build is faster than llvm's
> (only tried the make build, not the cmake build), and chromium's code
> base is considerably larger.

What David was saying is that Cray's compiler *non-empty* build ends
sooner than the LLVM *empty* build completes. Well, if only a small
translation unit needs to be compiled into a small executable (no long
compiler/linker waits) it may be possible but, again, it only speaks
about the relative sizes of LLVM/Cray's compiler.

WRT your Chromium example, the crux is not so much about what is faster,
but about what is considered slow. Chromium's empty build being faster
than LLVM is of no significance if LLVM's empty build can't be
considered annoyingly slow. And I wouldn't say that 1.3 seconds on a
rather ordinary desktop is annoyingly slow.