In GCCGO and gollvm, the logic for allocating one byte for the last field is:
1. the last field has zero size
2. the struct itself does not have zero size
3. the last field is not blank
this commit adds the last two conditions to runtime.structToFFI.
For golang/go#55146
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/431735
This only matters on systems that pass a struct with a single pointer
field differently than passing a single pointer. I noticed it on
32-bit PPC, where the reflect package TestDirectIfaceMethod failed.
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/195878
From-SVN: r275814
The gc compiler has started permitting go:linkname comments with a
single argument to mean that a function should be externally visible
outside the package. Implement this in the Go frontend.
Change the libgo runtime package to use it, rather than repeating the
name just to export a function.
Remove a couple of unnecessary go:linkname comments on declarations.
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/192197
From-SVN: r275239
CL 157557 changes the compiler to add one byte padding to
non-empty struct ending with a zero-sized field. Add the same
padding to the FFI type, so reflect.Call works.
This fixes test/fixedbugs/issue26335.go in the main repo.
Reviewed-on: https://go-review.googlesource.com/c/158018
From-SVN: r267956
The libffi library doesn't understand zero-sized objects.
When we see a zero-sized field in a struct, just skip it when
converting to the FFI data structures. There is no value to pass in
any case, so not telling libffi about the field doesn't affect
anything.
The test case for this is https://golang.org/cl/123316.
Fixesgolang/go#26335
Reviewed-on: https://go-review.googlesource.com/123335
From-SVN: r262651
As we move toward the Go 1.7 garbage collector, it's essential that all
allocation of values that can contain Go pointers be done using the
correct type descriptor. That is simplest if we do all such allocation
in Go code. This rewrites the code that converts from a Go type to a
libffi CIF into Go.
Reviewed-on: https://go-review.googlesource.com/33353
From-SVN: r242578
