We need to change the interface value representation for
concurrent garbage collection, so that there is no ambiguity
about whether the data word holds a pointer or scalar.
This CL does NOT make any representation changes.
Instead, it removes representation assumptions from
various pieces of code throughout the tree.
The isdirectiface function in cmd/gc/subr.c is now
the only place that decides that policy.
The policy propagates out from there in the reflect
metadata, as a new flag in the internal kind value.
A follow-up CL will change the representation by
changing the isdirectiface function. If that CL causes
problems, it will be easy to roll back.
Update #8405.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews, r
https://golang.org/cl/129090043
A user reported heavy contention on fmt's printer cache. Avoid
fmt.Sprint. We have to do reflection anyway, and there was
already an asString function to use strconv, so use it.
This CL also eliminates a redundant allocation + copy when
scanning into *[]byte (avoiding the intermediate string)
and avoids an extra alloc when assigning to a caller's RawBytes
(trying to reuse the caller's memory).
Fixes#7086
R=golang-codereviews, nightlyone
CC=golang-codereviews
https://golang.org/cl/50240044
Make the copy directly in the convert switch instead of an extra loop.
Also stops converting nil-[]byte to zero-[]byte when assigning to *interface
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7962044
E.g conversions from numeric types to RawBytes are missing, what makes RawBytes unusable in some cases.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7783046
- convert from nil pointers to the nil interface{}
- dereference non-nil pointers
- convert from nil interface{}s to nil pointers
- allocate pointers for non-nil interface{}s
- tests for all of the above
R=golang-dev, bradfitz, rsc, rogpeppe
CC=golang-dev
https://golang.org/cl/5630052
