On Wed, 22 Mar 2023 14:07:14 GMT, Per Minborg <pminb...@openjdk.org> wrote:
>> Back to @PaulSandoz question - "how does the caller know what the structure >> contains?". The caller typically doesn't care too much about what the >> returned struct is. But it might care about which "values" can be captured. >> That said, the set of such interesting values, is not too surprising. As >> demonstrated in the example in the `Linker.capturedCallState` method, once >> the client knows the name (and "errno" is likely to be 90% case), everything >> else follows from there - as the layout can be used to obtain var handles >> for the required values. >> >> But, perhaps, now that I write this, I realize that what @PaulSandoz might >> _really_ be asking is: how do I know that e.g. the returned struct will not >> contain e.g. nested structs, sequences, or other non-sense. So we might >> specify (in a normative way) that the returned layout is a struct layout, >> whose member layouts are one or more value layouts (possibly with some added >> padding layouts). The names of the value layouts reflect the names of the >> values that can be captured. >> >> And _then_ we show an example of the layout we return for Windows/x64 (as >> that's more interesting). > > I've updated the specs as per how I interpret the comments above. Let me know > your thoughts on this. This is much clearer. Are the names of the struct members guaranteed to be symbols that can be found up via the linker's default lookup? i.e. a small set of important global variables. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/13079#discussion_r1152550849
