libgo: update to 1.8.3 release

    
    Reviewed-on: https://go-review.googlesource.com/45150

From-SVN: r249033

3 files changed, 15 insertions, 2 deletions

diff --git a/libgo/go/runtime/malloc.go b/libgo/go/runtime/malloc.go
index ed25782..05a69c9 100644
--- a/libgo/go/runtime/malloc.go
+++ b/libgo/go/runtime/malloc.go
@@ -412,10 +412,12 @@ func (h *mheap) sysAlloc(n uintptr) unsafe.Pointer {
 			if p == 0 {
 				return nil
 			}
+			// p can be just about anywhere in the address
+			// space, including before arena_end.
 			if p == h.arena_end {
 				h.arena_end = new_end
 				h.arena_reserved = reserved
-			} else if h.arena_start <= p && p+p_size-h.arena_start-1 <= _MaxArena32 {
+			} else if h.arena_end < p && p+p_size-h.arena_start-1 <= _MaxArena32 {
 				// Keep everything page-aligned.
 				// Our pages are bigger than hardware pages.
 				h.arena_end = p + p_size
@@ -425,6 +427,16 @@ func (h *mheap) sysAlloc(n uintptr) unsafe.Pointer {
 				h.arena_used = used
 				h.arena_reserved = reserved
 			} else {
+				// We got a mapping, but it's not
+				// linear with our current arena, so
+				// we can't use it.
+				//
+				// TODO: Make it possible to allocate
+				// from this. We can't decrease
+				// arena_used, but we could introduce
+				// a new variable for the current
+				// allocation position.
+
 				// We haven't added this allocation to
 				// the stats, so subtract it from a
 				// fake stat (but avoid underflow).
diff --git a/libgo/go/runtime/mbitmap.go b/libgo/go/runtime/mbitmap.go
index 2b00493..a7ccc65 100644
--- a/libgo/go/runtime/mbitmap.go
+++ b/libgo/go/runtime/mbitmap.go
@@ -374,6 +374,7 @@ func heapBitsForAddr(addr uintptr) heapBits {
 // heapBitsForSpan returns the heapBits for the span base address base.
 func heapBitsForSpan(base uintptr) (hbits heapBits) {
 	if base < mheap_.arena_start || base >= mheap_.arena_used {
+		print("runtime: base ", hex(base), " not in range [", hex(mheap_.arena_start), ",", hex(mheap_.arena_used), ")\n")
 		throw("heapBitsForSpan: base out of range")
 	}
 	return heapBitsForAddr(base)
diff --git a/libgo/go/runtime/mgc.go b/libgo/go/runtime/mgc.go
index f828e7c..5cee12d 100644
--- a/libgo/go/runtime/mgc.go
+++ b/libgo/go/runtime/mgc.go
@@ -1908,7 +1908,7 @@ func gchelper() {
 		traceGCScanDone()
 	}
 
-	nproc := work.nproc // work.nproc can change right after we increment work.ndone
+	nproc := atomic.Load(&work.nproc) // work.nproc can change right after we increment work.ndone
 	if atomic.Xadd(&work.ndone, +1) == nproc-1 {
 		notewakeup(&work.alldone)
 	}