RFR: JDK-8034788 Rewrite toolchain.m4 to support multiple toolchains per platform (original) (raw)

Henry Jen henry.jen at oracle.com
Fri Feb 14 19:50:15 UTC 2014

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

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