On 02/13/2014 12:41 AM, Magnus Ihse Bursie wrote:
Henry,
- Do we want to allow convention name cc and CC and detect what it
is or simply ask for explicit choice as it is imeplemted now?
Although I don't think it's likely for a system to install, say
gcc, as cc instead of create a symbolic link alias for gcc, I
cannot be sure.
I didn't say so in my previous mail, but one follow-up functionality
I'm planning to implement is to set compiler using CC or CXX. In this
case, we'll try to detect toolchain type automatically. But unless we
specify CC explicitly like that, I believe the best way is to default
to a toolchain and try to detect it using conventional names, e.g.
bcc.
I think this is important to recent parfait effort as well or any
wrapping tools for compiler.
- I understand clang is not a goal for this patch. From experience,
it's almost work like gcc. Does it make sense to have gcc flags as
a fallback? This bring up the question before, should we have a
fallback default to unknown toolchain? Even if we check for
supported toolchain, all such setting should probably still be
defensive with gcc as default. Otherwise, I can configure with
clang but quite a few setting would be missing.
I do not like the idea of a fallback like that. If we cannot detect
the compiler, then things are likely to go wrong. And one core value
in the configure thinking is that if it should fail, it should fail
early, in the configure step, not in make.
The one reason I can see for not enforcing us to detect compiler
correctly is if you're adding support for a new compiler, like clang,
and have not bothered to write the new detection code yet. In that
case, you'll just have to comment out the check.
I agree we should fail early, and what I meant to say is that we need to
have a catch-all on those toolchain specific setting code to either have
an error or minimum default(perhaps a nop, which is probably what is
implemented already).
The thinking is to make sure we won't miss any spot that need to be
modified when adding a new toolchain support.
Cheers,
Henry
