system description

[MacGregor, Duncan (GE Energy Management)]

I agree that annotations are better than a meta-file, but what about
borrowing some of the work from multi-release jars and storing the classes
under some hierarchy that matches the OS/CPU/ABI? That would allow for the
output of extract on multiple architectures to be safely combined and
loaded as appropriate.

Duncan.

On 22/12/2015, 05:08, "panama-dev on behalf of John Rose"
<panama-dev-bounces at openjdk.java.net on behalf of john.r.rose at oracle.com>
wrote:

>The output of jextract needs to describe the OS, CPU, and ABI
>that libclang was assuming when it processed the header files.
>
>Since we are using JAR files as output, this means we either
>use some meta-file, or else we annotate all the top level interfaces.
>I think annotations are a good way to go, since they allow jextract
>outputs to be combined safely without worrying about meta-files.
>
>Below is a sketch of a way to organize this information.
>
>Influences are Unix /bin/uname, Python's cpuinfo script,
>and the porting infrastructure from HotSpot and Maxine.
>
>Comments?
>
>‹ John
>
>/** An ABI is determined by an OS and a CPU.
> *  Rarely, one or more option settings
> *  may be needed to resolve ambiguity.
> */
>@interface ABI {
>    /** The operating system where this ABI takes effect. */
>    OS os() default @OS(system=SystemFamily.UNKNOWN);
>    /** The CPU type on which this ABI takes effect. */
>    CPU cpu() default @CPU(arch=CPUArch.UNKNOWN);
>    /** What is the byte order for this ABI? */
>    ByteOrder order() default ByteOrder.UNKNOWN;
>    /** What is the data model for this ABI? */
>    DataModel model() default DataModel.UNKNOWN;
>    /** Option settings, if any, should be of the form "name=value". */
>    String[] options() default {};
>}
>
>/** Enumeration of byte orders.
> *  {@code NATIVE} means the byte order of the end-user platform.
> *  @see 
>https://urldefense.proofpoint.com/v2/url?u=http-3A__en.wikipedia.org_wiki_
>Endianness&d=CwIFaQ&c=IV_clAzoPDE253xZdHuilRgztyh_RiV3wUrLrDQYWSI&r=aV08z5
>NG4zOHLhrrnNlp8QUqO3qoRJCN9uQ9bkMSeqE&m=Nh1Xeq7GEYZyt9eFd485YtVmmpK1uUJ99T
>6pJPILOFw&s=CBmrGUq5FMr_vLqcdqGLWiXbFunUv_hoLyfa-E5kjYQ&e=
> */
>enum ByteOrder { UNKNOWN, NATIVE, LITTLE, BIG }
>
>/** Enumeration of data models determining the length in bits of C types
> *  {@code int}, {@code long}, {@code long long}, and {@code void*}
>(pointers).
> *  {@code NATIVE} means the data model of the end-user platform.
> *  @see 
>https://urldefense.proofpoint.com/v2/url?u=http-3A__en.wikipedia.org_wiki_
>64-2Dbit-5Fcomputing-2364-2Dbit-5Fdata-5Fmodels&d=CwIFaQ&c=IV_clAzoPDE253x
>ZdHuilRgztyh_RiV3wUrLrDQYWSI&r=aV08z5NG4zOHLhrrnNlp8QUqO3qoRJCN9uQ9bkMSeqE
>&m=Nh1Xeq7GEYZyt9eFd485YtVmmpK1uUJ99T6pJPILOFw&s=eH_8xn8vjUISdBo6s_Md5mNSv
>si5BxDDUOgsgoVQeb8&e=
> */
>enum DataModel { UNKNOWN, NATIVE, ILP32, LP64, LLP64, ILP64 }
>
>/** An OS is determined by a system family,
> *  an optional release,
> *  and an optional set of option settings.
> *  The CPU does not need to be specified.
> *  @see 
>https://urldefense.proofpoint.com/v2/url?u=http-3A__en.wikipedia.org_wiki_
>Uname&d=CwIFaQ&c=IV_clAzoPDE253xZdHuilRgztyh_RiV3wUrLrDQYWSI&r=aV08z5NG4zO
>HLhrrnNlp8QUqO3qoRJCN9uQ9bkMSeqE&m=Nh1Xeq7GEYZyt9eFd485YtVmmpK1uUJ99T6pJPI
>LOFw&s=focfYiCl9v-o03UUabQBEa3Echk5_bmyNaeMJQFpE2c&e=
> */
>@interface OS {
>    /** System family, as reported by {@code /bin/uname -s}. */
>    SystemFamily system();
>    /** System release, as reported by {@code /bin/uname -r}. */
>    String release() default "";
>    /** Option settings, if any, should be of the form "name=value". */
>    String[] options() default {};
>}
>
>/** Enumeration of system families, as reported by {@code /bin/uname -s},
>etc. */
>enum SystemFamily { UNKNOWN, LINUX, DARWIN, SOLARIS, WINDOWS }
>
>/** A CPU type as reported by {@code /bin/uname -mpi}.
> *  @see 
>https://urldefense.proofpoint.com/v2/url?u=http-3A__en.wikipedia.org_wiki_
>Uname&d=CwIFaQ&c=IV_clAzoPDE253xZdHuilRgztyh_RiV3wUrLrDQYWSI&r=aV08z5NG4zO
>HLhrrnNlp8QUqO3qoRJCN9uQ9bkMSeqE&m=Nh1Xeq7GEYZyt9eFd485YtVmmpK1uUJ99T6pJPI
>LOFw&s=focfYiCl9v-o03UUabQBEa3Echk5_bmyNaeMJQFpE2c&e=
> */
>@interface CPU {
>    CPUArch arch();
>    String processor() default ""; // /bin/uname -p
>    String platform() default ""; // /bin/uname -i/-m
>    String[] options() default {}; // e.g., {"family=6", "model=58",
>"stepping=9", "brand=Intel(R) Core(TM) i7-3615QM CPU @ 2.30GHz"}
>}
>
>/** Enumeration of ISA families, as reported by {@code /bin/uname -m},
>etc. */
>enum CPUArch { UNKNOWN, X86_64, I386, ARM, SPARC, PPC }
>
>
>////////////////
>// Example use:
>@ABI(os=@OS(system=SystemFamily.DARWIN),
>     cpu=@CPU(arch=CPUArch.X86_64),
>     order=ByteOrder.LITTLE,
>     model=DataModel.LP64)
>interface mylib { }
>////////////////
>