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| author | Ian Lance Taylor <ian@gcc.gnu.org> | 2019-08-23 22:38:58 +0000 |
|---|---|---|
| committer | Ian Lance Taylor <ian@gcc.gnu.org> | 2019-08-23 22:38:58 +0000 |
| commit | 6ae361ae458d4056d6c36fa42f1775c417457b10 (patch) | |
| tree | 2abbeb7a9dc1276b8a53259a89738319fdee0f45 /libgo | |
| parent | 457dac402027dd7e14543fbd59a75858422cf6c6 (diff) | |
compiler: record pointer var values to remove write barriers
Record when a local pointer variable is set to a value such that
indirecting through the pointer does not require a write barrier. Use
that to eliminate write barriers when indirecting through that local
pointer variable. Only keep this information per-block, so it's not
all that applicable.
This reduces the number of write barriers generated when compiling the
runtime package from 553 to 524.
The point of this is to eliminate a bad write barrier in the bytes
function in runtime/print.go. Mark that function nowritebarrier so
that the problem does not recur.
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/191581
From-SVN: r274890
Diffstat (limited to 'libgo')
| -rw-r--r-- | libgo/go/runtime/print.go | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/libgo/go/runtime/print.go b/libgo/go/runtime/print.go index 8c396442862..14d546d6d33 100644 --- a/libgo/go/runtime/print.go +++ b/libgo/go/runtime/print.go @@ -35,6 +35,7 @@ import ( // should use printhex instead of printuint (decimal). type hex uint64 +//go:nowritebarrier func bytes(s string) (ret []byte) { rp := (*slice)(unsafe.Pointer(&ret)) sp := stringStructOf(&s) |