runtime: assume precisestack, copystack, StackCopyAlways, ScanStackByFrames
Commit to stack copying for stack growth.
We're carrying around a surprising amount of cruft from older schemes.
I am confident that precise stack scans and stack copying are here to stay.
Delete fallback code for when precise stack info is disabled.
Delete fallback code for when copying stacks is disabled.
Delete fallback code for when StackCopyAlways is disabled.
Delete Stktop chain - there is only one stack segment now.
Delete M.moreargp, M.moreargsize, M.moreframesize, M.cret.
Delete G.writenbuf (unrelated, just dead).
Delete runtime.lessstack, runtime.oldstack.
Delete many amd64 morestack variants.
Delete initialization of morestack frame/arg sizes (shortens split prologue!).
Replace G's stackguard/stackbase/stack0/stacksize/
syscallstack/syscallguard/forkstackguard with simple stack
bounds (lo, hi).
Update liblink, runtime/cgo for adjustments to G.
LGTM=khr
R=khr, bradfitz
CC=golang-codereviews, iant, r
https://golang.org/cl/137410043
diff --git a/src/runtime/cgo/gcc_openbsd_amd64.c b/src/runtime/cgo/gcc_openbsd_amd64.c
index 5f0d3bb..35b359b 100644
--- a/src/runtime/cgo/gcc_openbsd_amd64.c
+++ b/src/runtime/cgo/gcc_openbsd_amd64.c
@@ -92,7 +92,7 @@
setg_gcc = setg;
pthread_attr_init(&attr);
pthread_attr_getstacksize(&attr, &size);
- g->stackguard = (uintptr)&attr - size + 4096;
+ g->stacklo = (uintptr)&attr - size + 4096;
pthread_attr_destroy(&attr);
// Locate symbol for the system pthread_create function.
@@ -127,7 +127,8 @@
pthread_attr_init(&attr);
pthread_attr_getstacksize(&attr, &size);
- ts->g->stackguard = size;
+ // Leave stacklo=0 and set stackhi=size; mstack will do the rest.
+ ts->g->stackhi = size;
err = sys_pthread_create(&p, &attr, threadentry, ts);
pthread_sigmask(SIG_SETMASK, &oset, nil);
@@ -148,14 +149,6 @@
ts = *(ThreadStart*)v;
free(v);
- ts.g->stackbase = (uintptr)&ts;
-
- /*
- * _cgo_sys_thread_start set stackguard to stack size;
- * change to actual guard pointer.
- */
- ts.g->stackguard = (uintptr)&ts - ts.g->stackguard + 4096;
-
/*
* Set specific keys.
*/
