[PATCH] fix zero builds for "unknown" architectures

[David Holmes]

Is this considered too hackish (assuming it works):

const char* search_string = IA32_ONLY("model name"; // ) \
                             AMD64_ONLY("model name"; //) \
                             IA64_ONLY("";//) \
                             SPARC_ONLY("cpu"; //) \
                             ARM32_ONLY("Processor"; //) \
                             PPC_ONLY("Processor"; //) \
                             AARCH64_ONLY("Processor"; //) \
                             "Processor";

The idea being that if any _ONLY is defined the "default" becomes part 
of a comment.

The strncpy case could also add a

const char* cpu_string = ... IA32_ONLY(...) ...

Though looking at all the Elf stuff earlier in the file I have to wonder 
whether we can consolidate some of this arch related stuff somehow.

David

On 10/09/2015 9:59 AM, David Holmes wrote:
> On 10/09/2015 2:56 AM, Coleen Phillimore wrote:
>>
>> I think I like patch #1 better.   I will sponsor it and make sure it
>> works on my machine.   Thank you for fixing this on the other platforms.
>
> I think there should be a way to detect an unknown arch via the build
> mechanics. I would think an unknown arch would also impact includes of
> <os>_<arch> headers ... unless the "arch" is Zero in that case? In which
> case maybe we should be checking for Zero here?
>
> Also need to check the ARM versus ARM32 - as with PPC/PPC32/PPC64 I
> think plain ARM means 32-bit or 64-bit, but Aarch64 covers 64-bit.
>
> David
>
>> Coleen
>>
>> On 9/9/15 12:19 PM, Matthias Klose wrote:
>>> seen with jdk9 / tag jdk9-b80.  zero builds which don't match one of
>>> the hotspot
>>> architectures fail to build in src/os/linux/vm/os_linux.cpp, because
>>> there is no
>>> default / or else clause:
>>>
>>> const char* search_string = IA32_ONLY("model name") AMD64_ONLY("model
>>> name")
>>>                              IA64_ONLY("") SPARC_ONLY("cpu")
>>>                              ARM32_ONLY("Processor")
>>> PPC_ONLY("Processor")
>>> AARCH64_ONLY("Processor");
>>>
>>> and:
>>>
>>>    strncpy(cpuinfo, IA32_ONLY("x86_32") AMD64_ONLY("x86_32")
>>>                     IA64_ONLY("IA64") SPARC_ONLY("sparcv9")
>>>                     ARM32_ONLY("ARM") PPC_ONLY("PPC64")
>>> AARCH64_ONLY("AArch64"),
>>> length);
>>>
>>> attached are two alternate patches how to fix this, either by not
>>> using the
>>> *_ONLY macros, or by defining an UNKOWN_ARCH_ONLY macro.
>>>
>>> Two other issues:
>>>   - The zero builds only define ARM, not ARM32, so the clause
>>>     should be ARM_ONLY (or at least an ARM_ONLY added).
>>>   - The cpuinfo string seems to be wrong for AMD64_ONLY.
>>>
>>> Verified that zero builds without errors with on of these patches.
>>>
>>> Attaching both patches.
>>>
>>>    Matthias
>>>
>>