| commit | 22deed0d6aa6688424346ecf1339687a1a54f10c | |
| author | ian <ian@138bc75d-0d04-0410-961f-82ee72b054a4> | |
| Fri, 23 Jun 2017 16:03:49 +0000 (23 16:03 +0000) | ||
| committer | ian <ian@138bc75d-0d04-0410-961f-82ee72b054a4> | |
| Fri, 23 Jun 2017 16:03:49 +0000 (23 16:03 +0000) | ||
| tree | 3f8b464d9ac9de6affa319ea9639ee19ef983302 | treesnapshot (tar.gz zip) |
| parent | 2e376e459d7dde2c0481460c580c4ec9470e7827 | commitdiff |
compiler: add go:notinheap magic comment
Implement go:notinheap as the gc compiler does. A type marked as
go:notinheap may not live in the heap, and does not require a write
barrier. Struct and array types that incorporate notinheap types are
themselves notinheap. Allocating a value of a notinheap type on the
heap is an error.
This is not just an optimization. There is code where a write barrier
may not occur that was getting a write barrier with gccgo but not gc,
because the types in question were notinheap. The case I found was
setting the mcache field in exitsyscallfast.
Reviewed-on: https://go-review.googlesource.com/46490
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@249594 138bc75d-0d04-0410-961f-82ee72b054a4
Implement go:notinheap as the gc compiler does. A type marked as
go:notinheap may not live in the heap, and does not require a write
barrier. Struct and array types that incorporate notinheap types are
themselves notinheap. Allocating a value of a notinheap type on the
heap is an error.
This is not just an optimization. There is code where a write barrier
may not occur that was getting a write barrier with gccgo but not gc,
because the types in question were notinheap. The case I found was
setting the mcache field in exitsyscallfast.
Reviewed-on: https://go-review.googlesource.com/46490
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@249594 138bc75d-0d04-0410-961f-82ee72b054a4