commit 4e0a51c210ededa82809756ca1cc72b1fb1def8d
author Carl Shapiro <cshapiro@google.com> Tue May 28 17:59:10 2013 -0700
committer Carl Shapiro <cshapiro@google.com> Tue May 28 17:59:10 2013 -0700
tree 73e39d7d22cc17088ea10bcd2bc0ce165b45ef0d
parent 8bbb08533dab0dcf627db0b76ba65c3fb9b1d682

cmd/5l, cmd/6l, cmd/8l, cmd/gc, runtime: generate and use bitmaps of argument pointer locations

With this change the compiler emits a bitmap for each function
covering its stack frame arguments area.  If an argument word
is known to contain a pointer, a bit is set.  The garbage
collector reads this information when scanning the stack by
frames and uses it to ignores locations known to not contain a
pointer.

R=golang-dev, bradfitz, daniel.morsing, dvyukov, khr, khr, iant, cshapiro
CC=golang-dev
https://golang.org/cl/9223046