libgo: update to Go 1.8 release candidate 1

    
    Compiler changes:
      * Change map assignment to use mapassign and assign value directly.
      * Change string iteration to use decoderune, faster for ASCII strings.
      * Change makeslice to take int, and use makeslice64 for larger values.
      * Add new noverflow field to hmap struct used for maps.
    
    Unresolved problems, to be fixed later:
      * Commented out test in go/types/sizes_test.go that doesn't compile.
      * Commented out reflect.TestStructOf test for padding after zero-sized field.
    
    Reviewed-on: https://go-review.googlesource.com/35231

gotools/:
	Updates for Go 1.8rc1.
	* Makefile.am (go_cmd_go_files): Add bug.go.
	(s-zdefaultcc): Write defaultPkgConfig.
	* Makefile.in: Rebuild.

From-SVN: r244456

1 files changed, 16 insertions, 10 deletions

diff --git a/libgo/go/context/context.go b/libgo/go/context/context.go
index f8ce9cc..0aa7c24 100644
--- a/libgo/go/context/context.go
+++ b/libgo/go/context/context.go
@@ -159,9 +159,9 @@ var DeadlineExceeded error = deadlineExceededError{}
 
 type deadlineExceededError struct{}
 
-func (deadlineExceededError) Error() string { return "context deadline exceeded" }
-
-func (deadlineExceededError) Timeout() bool { return true }
+func (deadlineExceededError) Error() string   { return "context deadline exceeded" }
+func (deadlineExceededError) Timeout() bool   { return true }
+func (deadlineExceededError) Temporary() bool { return true }
 
 // An emptyCtx is never canceled, has no values, and has no deadline. It is not
 // struct{}, since vars of this type must have distinct addresses.
@@ -252,9 +252,9 @@ func propagateCancel(parent Context, child canceler) {
 			child.cancel(false, p.err)
 		} else {
 			if p.children == nil {
-				p.children = make(map[canceler]bool)
+				p.children = make(map[canceler]struct{})
 			}
-			p.children[child] = true
+			p.children[child] = struct{}{}
 		}
 		p.mu.Unlock()
 	} else {
@@ -314,8 +314,8 @@ type cancelCtx struct {
 	done chan struct{} // closed by the first cancel call.
 
 	mu       sync.Mutex
-	children map[canceler]bool // set to nil by the first cancel call
-	err      error             // set to non-nil by the first cancel call
+	children map[canceler]struct{} // set to nil by the first cancel call
+	err      error                 // set to non-nil by the first cancel call
 }
 
 func (c *cancelCtx) Done() <-chan struct{} {
@@ -376,7 +376,7 @@ func WithDeadline(parent Context, deadline time.Time) (Context, CancelFunc) {
 		deadline:  deadline,
 	}
 	propagateCancel(parent, c)
-	d := deadline.Sub(time.Now())
+	d := time.Until(deadline)
 	if d <= 0 {
 		c.cancel(true, DeadlineExceeded) // deadline has already passed
 		return c, func() { c.cancel(true, Canceled) }
@@ -406,7 +406,7 @@ func (c *timerCtx) Deadline() (deadline time.Time, ok bool) {
 }
 
 func (c *timerCtx) String() string {
-	return fmt.Sprintf("%v.WithDeadline(%s [%s])", c.cancelCtx.Context, c.deadline, c.deadline.Sub(time.Now()))
+	return fmt.Sprintf("%v.WithDeadline(%s [%s])", c.cancelCtx.Context, c.deadline, time.Until(c.deadline))
 }
 
 func (c *timerCtx) cancel(removeFromParent bool, err error) {
@@ -443,7 +443,13 @@ func WithTimeout(parent Context, timeout time.Duration) (Context, CancelFunc) {
 // Use context Values only for request-scoped data that transits processes and
 // APIs, not for passing optional parameters to functions.
 //
-// The provided key must be comparable.
+// The provided key must be comparable and should not be of type
+// string or any other built-in type to avoid collisions between
+// packages using context. Users of WithValue should define their own
+// types for keys. To avoid allocating when assigning to an
+// interface{}, context keys often have concrete type
+// struct{}. Alternatively, exported context key variables' static
+// type should be a pointer or interface.
 func WithValue(parent Context, key, val interface{}) Context {
 	if key == nil {
 		panic("nil key")