[foreign-abi] RFR 8228486: Add ABI-specific layout constants

[Jorn Vernee]

The tests pass on Windows. Overall the patch looks good

- in TestUpcall you seem to be using the SysV.C_POINTER constant instead 
of the magic one.

- Do we need to distinguish between POINTER and INTEGER class? Shouldn't 
this just be about in which register it's passed? It looks like the 
isPointer predicate is only used in the tests in order to construct 
dummy arguments, is there another way around this? (e.g. checking that 
the carrier is a MemoryAddress).

Some things that I can look into:

* We can mark vararg arguments with a layout annotation on Windows to be 
able to support vargargs on Windows as well.

* I think some of the code in Window's CallingSequenceBuilderImpl could 
be removed at this point (e.g. the x87 stuff), since it's not supported 
by the Windows C ABI any ways.

Jorn

On 2019-07-22 19:23, Maurizio Cimadamore wrote:
> Hi,
> the recent push for JDK-8228447, as expected, broke the foreign-abi
> branch, since that branch depended on the ValueLayout::isIntegral
> accessor.
> 
> This patch replaces that logic with the custom layout annotation logic
> discussed in [1]:
> 
> http://cr.openjdk.java.net/~mcimadamore/panama/8228486/
> 
> This patch makes the following changes:
> 
> * introduces three set of annotated layout constants, one for supported 
> ABI
> * the annotations point directly at the ABI-specific argument classes
> * I've consolidated ArgumentClass a bit, so that now there's a common,
> ABI-agnostic super-interface with some general predicates
> * AddressLayout has been removed (we can just look for 
> argumentClass::isPointer)
> * the tests have been tweaked to use the new ABI-specific constants;
> since the test has to work across platforms, all ABI test use a new
> interface which imports the 'right' set of constants
> 
> While the patch might be a bit raw (I've only tested on Linux x64), I
> like where this is going.
> 
> Maurizio